Paxman-Lentz Steam Engines

On this page:
An introduction to Paxman-Lentz engines
Dr Hugo Lenz
The Key Features of The Lentz Engine.
Transcript of Paxman-Lentz Steam Engines brochure of 1915 with detailed descriptions of the engines' features and tables of dimensions and power outputs.
Listing of Paxman-Lentz Engine Orders and Installations, including details of customers and applications.
Details of Conversions to Lentz Valve Gear undertaken by Paxman on other makers' engines.

Related Pages:
Paxman and Steam Engineering • Paxman-Lentz Steam Engine - No 18581 • Surviving Paxman Stationary Steam Engines • Lentz Valves for Locomotives

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Introduction

Designed by Dr Hugo Lenz, the first Lentz engine was shown at the Como Exhibition of 1899 where it won first prize. The following year, at the Paris Exhibition, it was awarded the Grand Prix and its inventor the Gold Medal. The early application of Lentz valve gear in installations such as the City of Rome Electric Station, the International Electric Company's central station in Vienna, and the Municipal Electrical Station also in Vienna, demonstrated major fuel savings and rapidly led to its wider adoption. Lentz engines were built by a number of manufacturers in mainland Europe, notably MAN in Germany, by Davey, Paxman & Co in England, and by Erie City Iron Works, Pennsylvania in the USA.

Paxman started making Lentz engines in 1907 and built about 130 of them by the time the last was despatched in 1934. Most were horizontal tandem compound types. The others were 10 cross-coupled compounds, 2 coupled tandem compounds, 12 single cylinder engines and 2 verticals. Details of all these are given in the table of orders and installations lower down this page.

Paxman-Lentz in build at Colchester
The above photograph of a large compound Paxman-Lentz in build at Colchester is dated October 1930.
The Paxman photographic archive index indicates that it is of a 500HP cross compound for 'driving a duplex
ammonia compressor with a 300 ton capacity'. It must therefore be No 23594 made for the
Lightfoot Refrigeration Co for a butter store in Auckland, New Zealand.

A major application of Paxman-Lentz engines was in the field of electrical power generation, the generators being driven directly from the crankshaft. A good number were supplied for driving refrigeration compressors which were made by Paxman for the Linde British Refrigeration Co and its successor, the Lightfoot Refrigeration Co. Others were supplied for driving machinery in mills and factories in a diverse range of industries. Details of the various applications can be found in the orders and installations table referred to above.

Surviving Paxman-Lentz Engines

Only two Paxman-Lentz engines are known to have survived. Photographs and a technical description of one, No 18581, can be found on the page Paxman-Lentz Steam Engine - No 18581. Details and a photograph of the other, No 18842, are shown on the Surviving Paxman Stationary Steam Engines page.

Dr Hugo Lenz (1859 - 1944)

Dr Hugo Lenz was born in South Africa in 1859. When he was six years old his father died and the family returned to their native Germany. Lenz trained and worked in Prussia as a naval engineer before setting up his own engine business in Vienna when he was aged 28. Later in life, during the 1920s, he is believed to have had an experimental workshop in or near Paxman's Standard Ironworks on Hythe Hill. Although there was no 't' in Lenz's surname, his engines and patents were always called 'Lentz' as this was thought easier for English-speaking people to pronounce.

Key Features of The Lentz Engine

During the latter part of the nineteenth century the use of high-pressure superheated steam was increasingly adopted for steam engines to improve their efficiency. The slide valve, which had been widely used on early steam engines, was not satisfactory for controlling superheated steam. Consequently the drop-valve, actuated by trip gear, became the conventional solution for large stationary engines. However it was not suitable for high-speed running and had another major weakness. When the trip mechanism released the valve to shut off steam to the cylinder, the valve was forced sharply onto its seat by a strong coil spring. Not only did this make it noisy but the constant shocks and hammering resulted in rapid wear to the valve and its seat. Steam tightness of the valve quickly deteriorated necessitating frequent expensive maintenance. To lessen the impact of the valve upon its seat, a dashpot was generally fitted to check its descent. This was a compromise running counter to the purpose of trip gear which was to ensure rapid closing of the valve and a quick cut-off of steam to the cylinder.

In addition to the requirement for engines to operate satisfactorily on superheated steam, the close governing of an engine's speed became an important issue in the late nineteenth century. A rapidly growing application of large steam engines was electrical power generation where it was essential to maintain a constant speed under conditions of varying load to minimise fluctuations in voltage and current.

Key features of the engine developed by Lenz were its great economy in steam consumption, due to its suitability for operating with high-pressure superheated steam, and its ability to run continuously and quietly at high piston and crankshaft speeds.Lentz Valve These characteristics were derived from Lenz's patent valve gear, using poppet valves and positive valve gear, which provided greater control over the operation of the steam inlet valves. The engine embodied two other patents: the 'inertia' type governor, which enabled the engine to maintain a steady, constant speed under varying loads, and frictionless metallic packing. These distinctive features of the Lentz engine are described in detail in the following sections of this page and in the transcript of the 1915 Paxman-Lentz brochure below.

Lentz Valve Gear

The Lentz system overcame the limitations of the drop-valve arrangement by using poppet valves, each operated by a cam lever moved by an eccentric on the governor shaft. The valve was raised by the cam acting on a roller fitted to the valve spindle at 90°. During the entire travel of the valve the roller was kept in contact with the cam by means of a light spring in the bonnet above the valve. The cleverly designed profile of the cam allowed a prompt and full opening movement. More importantly, it allowed the valve to be rapidly lowered onto its seat in a smooth controlled manner. The cam did not move clear of the roller until after the valve was seated. This 'positive valve motion' was free from shock, making the gear entirely silent even when the engine was running at the highest speeds.

Right: Cross-sectional view of Lentz poppet valve, valve spindle and operating cam

Lentz engines were double acting, having four valves per cylinder: an admission valve on top and an exhaust valve underneath at each end of the cylinder. Lentz valve gear allowed exceptionally economical use of steam and high speeds which were not possible with trip gear. It also proved very reliable, giving long service with minimal maintenance.

The Lentz Governor

The Lentz engine was controlled by an inertia type governor mounted on the side shaft which was driven through gearing from the main crankshaft. The governor was directly connected to the two eccentrics which operated the valves on the high pressure cylinder. Extremely sensitive to variations in load, it provided excellent speed stability which was particularly important in electrical power generation applications.

Lentz Frictionless Metallic Packing

The use of high temperature superheated steam under high pressure placed greater demands not only on valve gear but also on joints around piston rods and valve spindles. Overcoming steam leakage through these joints, wear around them which accelerated leakage and the need for frequent maintenance, were major engineering challenges.

Lentz Metallic PackingHugo Lenz devised a new system for piston rod packing. Unlike many other metallic packings then available for use with superheated steam, it was frictionless, free from wear, free from risks of rod heating and from the need for constant maintenance. Some other types of packing relied on springs for their tightness, but springs rapidly lost their elasticity in contact with superheated steam and required frequent renewal.

The Lentz patent packing consisted of a series of cast-iron annular distance pieces, turned and ground dead true which fitted over the piston rod, but did not touch it. In between the distance pieces were a number of square section cast-iron rings, ground to fit the piston rod exactly. The alternate rings and distance pieces formed a series of chambers or voids where any steam leaking through the joint could expand and lose pressure. (The chambers were supplied with oil under pressure and drained.) Any steam escaping from the front chamber entered the second and there expanded. A small quantity might even escape to the third chamber where it expanded further but the last ring never showing the slightest leakage.

The design of the valve spindle joint was rather simpler but based on the same principle of steam losing more of its pressure each time it expands. The valve spindle was ground to fit inside a long bush. Grooves were turned on the spindle to form a labyrinth of chambers where any steam leaking into the joint could successively expand and lose pressure sufficiently to prevent it reaching the other end of the bush.

These arrangements did away with the need for stuffing boxes and soft packing. They were effective with the highest pressure of superheated steam, showing negligible wear and preserving steam tightness indefinitely.



Paxman-Lentz Brochure of 1915 - Publication No 723

NOTE: Not all the illustrations in the original publication are reproduced in the following transcript.

No.723

Paxman-Lentz
Steam Engines.

Manufactured by
Davey, Paxman & Co., Ltd.
COLCHESTER, England.


      London Office :
78 QUEEN VICTORIA STREET, E.C.
Telegraphic Address: "Paxman, Cannon, London."
Telephone: City 6787 and 6788.
Head Office & Works :
   COLCHESTER.
Telegraphic Address: "Paxman, Colchester."
Telephone: No.52.

Codes used :
A B C (4th and 5th editions), A1, Engineering (1st and 2nd editions), Lieber's,
Moreing & Neal, and Private Codes.

MAY, 1915


Introduction.

THE Lentz type of engine was well-known, and its advantages widely recognised on the Continent for some years before we took up its manufacture. The first engine of this type was exhibited at the Paris Exhibition of 1900, where it was awarded the Grand Prix, and the Inventor the Gold Medal. Since that date, its record has been brilliant and unbroken, and up to the end of 1910, the total horse-power of engines fitted with this valve gear made and supplied was over 3,000,000.

The economy of the Lentz engine is striking, and its success was instantaneous. At the City of Rome Electric Station, the Lentz valve gear was applied to four of their existing engines. As a result, the output was increased by 25%, without any increase in the boiler power being necessary!

At the International Electric Company's central station in Vienna, nineteen cross-compound engines fitted with piston valves, totalling about 20,000 h.p., were altered to the new Lentz system between 1900 and 1903. New high-pressure cylinders were supplied to each engine, the speed increased, and new alternators supplied at a cost of some £20,000, and the whole of this outlay was recouped in one year by the resultant economy in coal consumption.

At the Municipal Electrical Station in Vienna there were installed six horizontal quadruple-expansion engines fitted with a continental type of trip-gear, the total horse-power of the engines being about 24,000. The high-pressure cylinder of each engine was converted to the Lentz system, and as a result of this change, a saving of £650 per annum was effected on each engine by the decreased coal consumption.

Results such as the foregoing need no comment. We ourselves have now been manufacturing the Lentz type of engine for several years, and during that time have put down a large number of installations, which are giving uniformly good results.

The Paxman-Lentz engine is specially designed to give the greatest economy by using high pressures and superheated steam. It is also proportioned and constructed for continuous running at a high piston speed and revolution, all parts being made suitable for working satisfactorily under these conditions.

By the adoption of this engine a large amount of power can be put down with a minimum of floor space and foundation, thus making a great reduction in initial cost in buildings, etc.

ELECTRIC GENERATING PLANT. We have supplied a large number of these engines for electrical installations, the generators being driven direct from the shaft, for which they are eminently suitable.

MILL ENGINES. The Paxman-Lentz engine is also largely used for mill driving, for which purpose we have put down a great number. Where desired the speeds may be modified to suit requirements and general conditions. The powers developed, will of course vary with any alteration in speed, the duties given in tables on pages 17, 20 and 21 are based on the normal standard speeds, for which the engines are designed.

We give below some of the factories and works at which we have put down the Lentz engines, and can arrange for intending purchasers to inspect same in operation by appointment.

Electric Light Stations
Tramway Stations
Linen & Woollen Mills
Engineering Works
Chocolate Works
Refrigerating Plants
Flour Mills
Patent Fuel Works
Collieries
Fan Driving
Bacon Factories
Chemical Works
Timber Mills
Saw Mills
Rubber Works
Brick Works
Furniture Works
 

With regard to the illustrations contained in this catalogue (not included on this page) they are all taken from engines made. It must, however, be understood that we do not bind ourselves in future engines to the exact details as shown. Modifications may be made from time to time as experience dictates.

Special Advantages offered by the Paxman-Lentz Engines.

High Speed.
Silent Running.
Extreme Economy in Steam Consumption.
Close governing by patent Inertia Governor.
Patent Metallic Packing.
No soft Packing used ; no springs.
Positive motion to Valves — no jar or hammering.
Massive design of Bed.
Forced Lubrication.
Simplicity. Elegance of Design.
Suitable for the highest temperatures of Superheated Steam.
Large Power Output, compared with Floor Space occupied.
Accessibility of Working Parts.

Guarantee:
In lieu of any warranty implied by law, we expressly guarantee to repair or replace any part which within a period not exceeding twelve months from delivery may prove to be defective through bad material or workmanship ; but the engines are supplied on the condition that we shall not be liable for any losses incurred through stoppages, nor from any direct or consequential damages arising from such defect, and subject to oil approved by us having been used for the plant. Delivery of such replacements, in the case of engines abroad, will be made f.o.b. English shipping port.


Paxman-Lentz Steam Engines.

General Design. The machining of all parts is done with the most perfect and modern tools to exact gauges and limits, so that there is no trouble in supplying spare parts. Our tools and men are quite accustomed to work to one two-thousandth part of an inch.

Frame. The frame of the engine is very substantial, and is of the Giant girder type, with a very large surface resting upon the foundations, to ensure the utmost stability. It is capable of rigidly withstanding all the working strains of the engine. It will be noticed from the small illustration at the side that there is a very large bearing surface upon the concrete foundation under the crank-pin.

Cylinder. The cylinder rests upon sole plates embedded in the foundation. The feet of the cylinder are free to slide with the varying temperature of the main castings. The piston body is machined in a special manner, so as to ensure a large bearing surface upon the bottom of the cylinder. Non-conducting composition is used for covering the cylinder body, and the whole is neatly lagged with planished sheet steel.

Crankshaft. The crankshaft is of the best forged steel, of not less than 30 tons tensile, turned and polished all over.

Main Bearing. The main bearing is cast in one piece with the bedplate. The shell of the bearing is in four parts, fitted together, and lined with anti-friction metal. To remove the bottom portion, it is simply necessary to raise the crankshaft a fraction of an inch from its bed. Both main and outer bearings are provided with chain-oiling lubrication, and the oil can be renewed while the engine is running.

Valves. There are two admission and two exhaust valves to each cylinder, which are actuated by four independent eccentrics operated by the side shaft. This side shaft is driven by the conical surface shown at "A," and is really a friction drive pure and simple, the purpose of the bevel gearing being merely to ensure the correct setting of the valves being preserved ; the drive is therefore perfectly noiseless.

It will be noticed from the design in the next figure that these valves are free to lift easily in the case of any abnormal pressure arising within the cylinder, and each admission valve therefore also serves the purpose of a relief valve. Great care is taken in their design, and they are of such a form that even should distortion take place under excessive heat, this in no way affects the tightness of the valve, neither does it interfere with its easy working.

sectional view of Lentz valveValve Gear. This very novel and important detail of the Paxman-Lentz engine is shown in section by the illustration overleaf (see right). There are no stuffing boxes to the valve spindles, which are ground to fit the long bushes shown. Grooves are turned on the spindles to form a labyrinth packing, from which there is no leakage. The usual soft packing, with its attendant troubles and constant leakage, is thus done away with.

With the Paxman-Lentz valve gear, no dash-pot is used. The valve is raised by the cam lever "A," acting upon the roller "B," this lever being moved by the eccentric, and the whole movement is accomplished without noise or hammering. The roller "B" is always kept in close contact with the cam or lever "A" during the travel of the valve, by means of the spring shown in the bonnet. The cam does not move clear of the roller until after the valve is seated, and consequently, even when the engine is running at the highest speeds, the gear is entirely silent. In the Paxman-Lentz engines, the friction to which the valve is exposed is to all intents and purposes nil. The advantages of this system will be immediately recognised by the most casual observer, however slight his experience of valve gears.

In the case of a drop-valve engine actuated by trip-gear, the valve is suddenly released by the tripping action of the mechanism, and the valve is forced sharply upon its seat by the pressure of a strong coil spring. In order to diminish the damaging effect upon the valve and seat occasioned by this hammering action, its descent is checked by means of a dash-pot, and in precisely as much as the dash-pot is used, so the trip-gear fails in its original intention, which is to ensure the rapid closing of the steam admission valves. The whole complicated system is thus a compromise between, on the one hand, a sharp and clean cut-off obtained by the valve being hammered down violently upon its seat by the pressure of the spring, and, on the other hand, a gradual cut-off obtained by means of the retarding action of the dash-pot. With the Paxman-Lentz positive valve gear, on the contrary, there is no tripping movement, but the valve is lowered gently on to its seat by means of the cam (the profile of which is so shaped as to allow this to be done rapidly), and when the valve is seated, and not until then, the cam moves clear of the roller. This system renders quite permissible the employment of such high piston speeds and revolutions (even in the case of very large engines) as would be unattainable and quite out of the question with trip-gear.

We give on next page a diagram (omitted on this page) comparing the Paxman-Lentz positive valve gear with the ordinary trip gear, from which the striking simplicity and superiority of our gear is at once apparent.

Lubrication. All the parts subject to wear are efficiently lubricated; and forced lubrication, by means of a patent mechanically-driven oil pump of the sight-feed type, is provided for the valve chests, packing, and pistons. Oil trays are fitted wherever necessary, to prevent any possibility of the oil reaching the foundations.

Governor. The governor is another patented detail in connection with these engines, and is extremely sensitive to the slightest variation in the load. It is of the "inertia" type, mounted on the side shaft, and directly connected to the two high-pressure steam eccentrics ; these eccentrics are mounted on a sliding block keyed to the shaft, the governor controlling their eccentricity, and consequently varying the cut-off. The governor is shown in section below.

sectional illustration of Lentz governor

It consists of a heavy inertia ring "A," and two centrifugal weights "B" connected by a flat steel spring, which can be removed and replaced in a few minutes. The two weights "B B" are fitted to the carrier "C" fixed to the side shaft, the weights and the carrier being attached to the outer ring "A" (in the case of the weights by knee joints formed by "D" and "E," and in the case of the carrier by a spring) which performs the action of a flywheel. When the least variation of load, and consequently of speed, takes place, the inertia of the outer ring which tends to keep its speed constant, causes it to move relatively to the carrier, and by moving the eccentrics alters the cut-off to suit the changing load.

The governor regulates within an exceptionally short period, and the momentary change of speed due to the load being thrown on or off is only slightly in excess of the permanent change. Below, is given a speed diagram (omitted on this page) showing graphically the very slight alteration in speed occasioned by throwing the load suddenly off or on the engine, the resultant change of speed being hardly perceptible. The action of the Paxman-Lentz governor is immediate, and it combines extreme sensibility with a perfect stability only comparable with the best turbines.

A hand-wheel is provided at the end of the side shaft, to enable the speed of the engine to be altered while running, by adjusting the tension of the governor spring.

sectional view of Lentz metallic packingPacking. The piston-rod packing is made on the Lentz patent system. By eliminating springs, friction is reduced to a minimum, and as the packing is free from wear perfect steam-tightness is assured. The packing is shown in detail below (see right). It consists of a series of cast-iron annular distance pieces, turned and ground dead true. These annular distance pieces fit over the piston-rod, but do not touch it, whilst between the chambers are a number of square-section cast-iron rings, ground to fit the piston-rod exactly, forming with the distance pieces a series of chambers which are supplied with oil under pressure, and efficiently drained. Any steam escaping from the front chamber enters the second chamber, and there expands ; a small quantity may even escape to the third chamber, where it would undergo a further expansion, and so on ; but the last ring will never show the slightest leakage.

Many metallic packings which have been put on the market for use with superheated steam, owing to their construction, are more or less defective, because wherever there is friction there is wear, liability of the rod heating, useless work, and consequent constant attention. Packings which depend for tightness upon springs are subject to yet a further drawback, in that springs lose their elasticity rapidly in contact with superheated steam, and require frequent renewal.

Superheat. The Paxman-Lentz engine is specially suitable for use with the highest temperature of superheated steam. All valve and cylinder cover joints are made metal-to-metal, no soft packing of any kind being used, either for the stop valve, or any other part of the engine whatsoever.

Steam Consumption. The economy in steam consumption which is obtainable with engines of the Lentz type is unequalled by any other steam engine at present on the market, and the details given on page 3 of the Introduction are conclusive evidence as to this statement. The following figures are the results of some tests carried out on our engines :—

Duty of Engine.
(i.h.p.)
Pressure at Engine
Stop Valve. (lbs.)
Added Superheat.
(Fahrenheit)
Vacuum.Steam per i.h.p. per hour.
Superheated.Saturated.
366170150°26½"I0.4 lb.12.3 lb.
300140150°27"10.35 lb. 
600170100°25"10.91 lb. 
600170150°25"10.59 lb. 
570150175°27½"10.34 lb. 
425170150°Non Condg.13.45 lb. 
215170150°Non Condg.14.0 lb. 
537168175°24.25"10.38 lb. 
200170none26"13.25 lb.
250150150°25"10.44 lb. 

The first results mentioned above were obtained from a 27½" stroke engine, within two days of first running it, and an overload of 33.33 per cent. was easily obtained.

The results mentioned on the second line of the above table were from the tandem compound engine illustrated on page 24, when tested after working 10 months continuously in a flour mill ; the other results were obtained from engines driving Electric Generators direct coupled.

From these examples, it will be seen that even with a moderate steam pressure, the Paxman-Lentz engine is extremely economical, and this economy is maintained under actual working conditions.

Condensers. Wherever possible the adoption of a condenser is strongly recommended, as by this means an economy of at least 15 per cent. is obtained. The condensing apparatus itself can be placed in various positions with reference to the engine, to suit the space available, water level, and other local conditions. The type of air pump we employ embodies several original features, which have proved highly satisfactory in practice. The valves themselves consist of annular metallic rings, having a very small lift, and these give adequate area for the passage of the condensed steam and water ; and by reason of their small lift and weight are capable of working with the engines at the speeds listed in this catalogue. The air-pump piston is of the trunk type, and is made of gunmetal.

It is very often the case that air pumps and condensers do not receive the same care and attention either in design or construction, as practice has shown to be necessary for such adjuncts ; but upon our condensers the same scrupulous care is bestowed as is given to all parts of the engine, and the important questions of access and easy renewal have been most carefully kept in view.


Duties and Sizes of
The Paxman-Lentz Single-Cylinder Engines
CylinderFlywheel *Indicated Horse Power
Dia.
(in.)
Stroke
(in.)
Dia.Rev per
Minute
Non-CondensingCondensing
80 lbs.140 lbs.80 lbs.140 lbs.
Norm.Max.Norm.Max.Norm.Max.Norm.Max.
13248' 0"19010414613021099150128217
14248' 0"190122170154248116177150255
15¼27½9' 0"170157218197318149227193328
1627½9' 0"170164227205332155237200342
16¾309' 6"155176246222358168256217368
17¾309' 6"155202288252405190290246419
1933½11' 0"145239333300486227346293500
2033½11' 0"145266370333540252384326555
20½3612' 0"135280390350568266405344565
21½3612' 0"135310430387628293448380646
22½4213' 6"115333463417676315482408695
23½4213' 6"115365507456740345527446760
24½4815' 0"100394547493798373568482820
25½4815' 0"100428595535865405618524892
285416' 0"9052173465010554927536381086
295416' 0"9056178070011355308106871170

NOTES relating to Single-Cylinder Engines table above:
The catalogue shows IHPs for steam pressures of 80, 90, 100, 120 and 140 lbs per square inch. In the table above the IHPs for steam pressures of 90, 100 and 120 psi have been omitted.
* The catalogue does not give the weights of flywheels, saying only that these will be "According to requirements".

Duties and Sizes of
The Paxman-Lentz Compound Tandem & Coupled Engines
CylindersFlywheel *Indicated Horse Power
Dia. (in.)Stroke
(in.)
Dia.Rev per
Minute
Non-CondensingCondensing
High
Press
Low
Press
100 lbs.170 lbs.100 lbs.170 lbs.
Norm.Max.Norm.Max.Norm.Max.Norm.Max.
915½187' 6"210105115155175120132148166
10½17187' 6"210126137190210145160180200
11¼18½217' 6"200166180250277190210235260
1220217' 6"200195210290325220245275305
1321½248' 0"190245265365410277310345385
1423248' 0"190280305420470315350395440
15¼2527½9' 0"170340370510565380425480530
1626½27½9' 0"170380417575635430480540600
16¾27¾309' 6"155415455620685470525590655
17¾29¼309' 6"155460500690760525585655725
1931¼33½11' 0"145550595825910625700780870
2032¾33½11' 0"1456056559001000685765855950
20½343612' 0"13565071097510807408259251030
21½35½3612' 0"1357107751075117580590010101120
22½37½4213' 6"11578586011901300900100011201240
23½394213' 6"11585093012901400975108012101340
24½414815' 0"1009301020142015601070118513301475
25½434815' 0"10010251125156017001175130014601620
28465416' 0"9011901300180019701380150017001880
29485416' 0"9013001420197021401470165018502050

NOTES relating to Compound Engines table above:
The 18" and 21" stroke sizes were not made as Coupled Engines.
The catalogue shows IHPs for steam pressures of 100, 110, 120, 130, 140, 150, 160 and 170 lbs per square inch. In the table above the IHPs for steam pressures of 110, 120, 130, 140, 150 and 160 psi have been omitted.
* The catalogue does not give the weights of flywheels, saying only that these will be "According to requirements".



Paxman-Lentz Engine Orders and Installations

Details of the orders, customers and applications of the approximately 130 Paxman-Lentz engines built at Colchester are given in the table below. The information in this, and the subsequent table of Lentz conversions, is almost entirely the work of the late Graham Smart of Stourbridge, West Midlands. Graham spent a considerable amount of time at Colchester researching Paxman's Lentz engines and it is good to make the fruit of his considerable labours more widely available.

Abbreviations used in the table below:
HTC = Horizontal Tandem Compound   VC = Vertical Compound   SC = Single Cylinder
CC = Cross Compound Engine   CT = Coupled Tandem   SLV = Special Locomotive Valves
LH = left hand;   RH = right hand;   S/H = Second hand

Order
Date
Order
No
Engine
No
Engine DetailsCustomerEngine DutyDate
Sent
Drwg
Ref.
27-02-06787112874HTC 300 IHP
19" & 31½" x 33½" LH
E Marriage & Son
Felixstowe Dock
Suffolk
Rope drive to drive flour mill.
16 ropes.
(see Note 1 for more on this installation.
10-04-07 
23-05-0679843
engs
HTC 800 IHP
20" & 32¾" x 33½" LH
Crompton & Co
for Madras, India
Crankshaft generator - 500kW per engine.
For power station.
10-09-07 
23-05-0679852
engs
HTC 400 IHP
14½" & 24½" x 27½" LH
Crompton & Co
for Madras, India
Crankshaft generator - 250kW per engine.
For power station.
? 
23-05-0679862
engs
HTC 800 IHP
20" & 32¾" x 33½"
Crompton & Co
for Madras, India
Crankshaft generator - 500kW per engine.
For power station.
20-03-08 
23-05-0679872
engs
HTC 400 IHP
14½" & 24½" x 27½"
Crompton & Co
for Madras, India
Crankshaft generator - 250kW per engine.
For power station.
13-05-08 
14-09-068102?VC 150 rpm 875 bhp
27" & 47" x 20"
Electrical Construction Co, Wolverhampton
for City & S London Rly
Direct coupled to two 300kw DC dynamos (in tandem).
Stockwell Power Station, London
24-10-07 
21-10-07860414584CC 100 rpm 400 bhp
19" & 31¼" x 33½"
Strain & Robertson, Glasgow
for Officina Maria, Iquique, Chile
Rope drive to Siemens-Schuckert Alternator. 525V at 375 rpm.08-09-08 
14-07-088846?VC 140 rpm
5½" & 9" x 7"
City & Guilds of London Inst
Finsbury Technical College
Laboratory Test Engine (by 1932 at University College, Gower Street, London.)
Paxman microfilm records show this order was for "2 x vertical single crank double acting high speed open type … to be arranged so that they can be connected together by a coupling shaft when required to run as a compound engine." The HP cylinder to be 5½" x 7" and the LP to be 9" x 7", to run at 400rpm. The drawings were to be approved by Prof Coker. Paxman was also to supply 'test bars' 3" square by 6 foot long "for experiments in conductivity such as described in proceedings of Institute of Civil Engineers Vol 131 - 1891-8 on the law of condensation of steam, etc." The test bars were made of cylinder metal and also the liner metal. The instructions were that the cylinder material test bars were to be cast at the same time as the cylinders and covers.
20-09-09 
12-08-08888014873HTC 140 rpm 150 bhp
11¼" & 18½" x 20"
Davidson & Co, Sirocco Works, Belfast
for Shipley Colliery
Direct coupled to colliery ventilation fan.10-03-092009/2A
14-06-09914815170HTC 57 rpm 205 bhp
16¾" & 27¾" x 30"
Linde British Refrigeration
for Canning Town, London
Direct coupled to 15½" x 30" ammonia compressor on LH side of engine.29-09-09 
21-06-09916515190CC 180 rpm 300kW
16" & 26½" x 27½"
Thos F Craddock Esq, Leadenhall St, London EC
for Calcutta, India
Crankshaft generator.
Dick Kerr dynamo - 300kW.
13-12-09 
21-09-09922715256HTC 170 rpm 400 bhp
16" & 26½" x 27½"
Cwmaman Colliery Co Ltd
Aberaman, South Wales
Direct coupled to colliery ventilation fan (Sirocco).05-08-10 
25-11-09927315301HTC 57 rpm 205 bhp
16¾" & 27¾" x 30"
Linde British Refrigeration Co
for St Petersburg, Russia
Direct coupled to 15½" x 30" ammonia compressor on LH side of engine.
(Repeat of O/No 9148)
13-04-10 
07-02-10932915358HTC 120 rpm 300 IHP
16" & 26½" x 27½" LH
J S Fry & Sons Ltd, Wapping, Bristol
S/H in 1932 to McCall Brothers (woollen cloth manufacturers), Victoria Mills, Trowbridge
12' dia. flywheel grooved for 7 x 2" diameter ropes. At Trowbridge, drive from flywheel by 5 vee belts to Bruce Peebles & Co alternator, 500kVA, 440 volts, 656 amps.
Superheated. Steam pressure 160 psi. Surface condenser.
Engine stopped on 28 June 1961 and scrapped in June 1974.
12-05-10 
04-04-10936515394HTC 80 rpm
19" & 31¼" x 33½" RH
Stoate & Son, Somerset
(sold 8/25 via Geo Cohen & Sons)
Rope drive to factory 23076
13-04-10942815456HTC 900 IHP
19" & 31¼" x 33½" RH
AEG Electrical Co
for Uruguay
Crankshaft generator
(Power station)
03-10-10 
13-04-10942915457HTC 900 IHP
19" & 31¼" x 33½" RH
AEG Electrical Co
for Uruguay
Crankshaft generator
(Power station)
01-11-10 
13-04-10943015458HTC 450 IHP
14" & 23" x 24" RH
AEG Electrical Co
for Uruguay
Crankshaft generator
(Power station)
01-11-10 
13-04-10943115459HTC 450 IHP
14" & 23" x 24"
AEG Electrical Co
for Uruguay
Crankshaft generator
(Power station)
18-11-10 
03-09-10962015648HTC
12" & 20" x 21" RH
Chas & Thos Harris
Calne, Wiltshire
Crankshaft generator
(Bacon factory)
  
20-02-111086516893HTC 180 rpm 619 IHP
16" & 26½" x 27½" LH
Powell Duffryn Coal Co
for Penallta Colliery, South Wales
Direct coupled to colliery ventilation fan via Croft & Perkins coupling.  
25-02-111087616904HTC 135 rpm 500 bhp
17¾" & 29¼" x 30"
Bedwas Navigation Colliery Co
Bedwas, South Wales
Direct coupled to colliery ventilation fan via Hele-Shaw friction clutch.  
05-04-1110967 HTC
16" & 26½" x 27½"
Bath & West Counties Show
held Cardiff 31/5 to 5/6
(Engine built to O/No 10865 used - minus flywheel)
 22-05-11 
17-08-1111153 HTC 120 rpm 275 bhp
16" & 26½" x 27½"
Union Cold Storage Co
for Riga, Russia
Rope drive (to ammonia compressor?)
14 x 1½" dia ropes.
  
25-09-111123117259HTC 170 rpm 375kW
16" & 26½" x 27½"
Apperley & CurtisCrankshaft alternator (Siemens)15-05-1223015
23090
27-09-111123717265HTC 160 rpm 120kW
12" & 20" x 21"
Vestey Brothers
for Albert Dock, Liverpool
Crankshaft mounted DC dynamo (Crompton).04-01-1223012
14-05-121162817657HTC 185 rpm
160/170 bhp
12" & 20" x 21"
Raymond Allen Ltd, Cirencester
S/H to Samuel Salter, Homemill, Trowbridge
Rope drive to factory
8 x 1½" dia ropes
31-08-12 
25-05-121163917668HTC 147 rpm 180 IHP
12" & 20" x 21"
Plymouth Co-operative Flour Mills
S/H to Vestey Bros - see O/N 13141
Rope drive to flour mill
6 x 1¾" diameter ropes
28-09-1223379
23448
04-06-121167117701HTC 135 rpm
230-265 IHP
14" & 23" x 24"
Henry Workman Ltd
Woodchester Sawmills, Stroud, Glos
Rope drive to sawmill
10 x 1½" dia ropes
07-02-1323523
15-07-121173817768HTC 175 rpm 170 IHP
12" & 20" x 21"
Welch Margetson & Co
London
Rope drive07-05-13 
08-07-121174317773HTC 170 rpm
220-270 IHP
12" & 20" x 21"
Woodworkers Co
Chalford, Glos.
Rope drive
8 x 1½" dia ropes
01-02-13 
15-07-121174617776HTC 200 rpm
247-320 IHP
12" & 20" x 21"
E Sherry
Homerton, London.
(HP cyl of this engine exhib at Royal Show, Bristol, Jul 1913. O/No 12220)
Crankshaft generator and rope drive from flywheel
6 x 1.3/8" dia ropes
05-12-1323671
25-07-121175117781HTC 100/115 rpm
220-300 IHP
16" & 26½" x 24"
Powell Duffryn Coal Co
for Fforchaman Colliery, South Wales
Direct coupled to colliery ventilation fan via Zodel-Voith flexible coupling.19-03-13 
25-07-121175217782HTC 100/115 rpm
220-300 IHP
16" & 26½" x 27½"
Powell Duffryn Coal Co
for Aberaman Colliery, South Wales
Direct coupled to colliery ventilation fan via Zodel-Voith flexible coupling.08-04-13 
31-08-121184217872HTC 134 rpm
247-330 IHP
16" & 26½" x 27½"
Powell Duffryn Coal Co
for Cwm Neol Colliery, Aberdare, S Wales
Driving colliery ventilation fan by ropes from flywheel
12 x 1½" dia ropes
27-06-13 
04-11-121193917969HTC 60 rpm 264 bhp
20" & 32¾" x 33½"
(Standard 30" str bed used)
Linde British Refrigeration Co
for Vestey Brothers
Direct coupled to 18½" x 36" ammonia compressor - driven from outer end of crankshaft.27-02-13 
04-11-121194017970HTC 57 rpm 230 bhp
19" & 31½" x 33½"
Linde British Refrigeration Co
for Vestey Brothers
Direct coupled to 15½" x 30" ammonia compressor - driven from outer end of crankshaft.15-05-13 
04-11-121194117971HTC 57 rpm 130 bhp
15¼" & 25" x 27½"
Linde British Refrigeration Co
for Vestey Brothers
Direct coupled to 15½" x 30" ammonia compressor - driven from outer end of crankshaft.15-05-13 
04-11-121194217972HTC 57 rpm 230 bhp
19" & 31½" x 33½"
Linde British Refrigeration Co
for Vestey Brothers
Repeat of Order No 1194007-11-13 
04-11-121194317973HTC 57 rpm 130 bhp
15¼" & 25" x 27½"
Linde British Refrigeration Co
for Vestey Brothers
Repeat of Order No 1194107-11-13 
04-11-121194417974HTC 78 rpm 140 bhp
14" & 23" x 24"
Linde British Refrigeration Co
for Vestey Brothers,
sent to Battersea
Direct coupled to 13½" x 24½" ammonia compressor - driven from outer end of crankshaft.24-02-13 
06-01-131202418054CC 150 rpm 350kW
17¾" & 29¼" x 30"
Buxton, Cassina & Cie
for Pelotas, Argentina (Pelotas Tramways & Lighting)
Driving crankshaft DC generator (BT-H) for town tramways and lighting03-02-1423876
23950
06-01-131202518055CC 150 rpm 350kW
17¾" & 29¼" x 30"
As aboveAs above12-02-1423876
23950
03-02-131208618116HTC 170 rpm 450 bhp
16" & 26½" x 27½"
Ffaldau Collieries Co
Pontycymmer, S Wales
Direct coupled to 176" diameter mine ventilation fan.19-09-1323822
23834
27-03-131214318173HTC 145 rpm 700 bhp
20" & 32¾" x 33½"
Davidson & Co, Belfast
for Great Western Colliery Co, Cwm Colliery, Pontypridd
Direct coupled to "Sirocco" mine ventilation fan.05-03-1423922
15-04-131218018210HTC 210 rpm
100kW (148 bhp)
10½" & 17" x 18"
John Barker & Co Ltd
Kensington, London
(S/H to Welch Margetson & Co. 15-7-25)
Driving crankshaft generator - electricity supply for department store.22-11-1324112
15-04-131218118211HTC 190 rpm
250kW (362 bhp)
14" & 23" x 24"
John Barker - as above
(S/H to Union Cold Storage, Rockhampton, in 1925)
Driving crankshaft generator - electricity supply for department store.22-10-1324112
15-04-131218218212HTC 190 rpm
250kW (362 bhp)
14" & 23" x 24"
John Barker - as above
(S/H to Gomme, High Wycombe, Sept 1926)
As above.
(Order Nos 12180-12182 situated in basement of store.)
06-11-1324112
01-05-131222518255HTC 115 rpm 120 bhp
12" & 20" x 21"
F Skurray & Son
Town Flour Mills, Swindon, Wilts.
Driving flour mill by ropes. Flywheel grooved for 10 x 1¼" dia ropes.04-09-13 
09-12-1312502 HTC
16" & 26½" x 27½"
(Stock Order No 666)
for Universal (1914) Exhibition
Nottingham
Order cancelled..  
29-12-131252818558HTC 170 rpm 350 IHP
16" & 26½" x 27½"
Sussex Brick & Estates Ltd
Sussex
Driving brickworks by ropes. Flywheel grooved for 10 x 1½" dia ropes.17-02-1424364
26-01-141254718577HTC 150 rpm 500 bhp
17¾" & 29¼" x 30"
J M V Money Kent
for Cape Copper Co, Calcutta. (Later to Chasnalla Colliery, India)
Driving crankshaft generator (by Phoenix Dynamo Mfg Co, Bradford. 3-phase alternator - 300V)19-01-15 
26-01-141254818578HTC 150 rpm 500 bhp
17¾" & 29¼" x 30"
As aboveAs above19-01-15 
12-02-141255118581HTC 200 rpm
10½" & 17" x 18"
Poppe & Co
Isleworth, Mddx
(Second hand to Thomas Glenister & Co, furniture manufacturers, Temple Works, High Wycombe, in 1927)
Driving rubber processing machinery by gears (gears supplied by David Bridge).

At High Wycombe: steam pressure 170 psi; speed 212 rpm; output 220 bhp; 7' dia. flywheel; duty: driving an alternator. Engine stopped 1990 and removed 1996/7. more >
07-08-14 
24-04-141269018720HTC 170 rpm
300kW (437 bhp)
16" & 26½" x 27½"
Douglas Brothers
Bristol
Driving crankshaft generator - Crompton DC machine - 330kW at 220V.15-06-1424540
25372
27-05-1412733Not
built
HTC 165 rpm 225 IHP
12" & 20" x 21"
Golden Valley Ochre Co Ltd
Bristol
Driving factory by ropes
Flywheel grooved for 8 x 1" dia ropes.
(Order transferred to O/No 12835)
  
22-06-141276718797HTC 60 rpm 250 bhp
20" & 35" x 33½"
Vestey Brothers
for Manchuria
(Engine built to O/No 12771 used for this order)
Direct coupled to 15½" x 30" ammonia compressor - 150 bhp.
100 bhp by belt from flywheel
22-04-15 
22-06-141276918799HTC 60 rpm 150 bhp
16" & 30" x 27½"
Vestey Brothers
for Port Darwin, Australia
Direct coupled to 15½" x 30" ammonia compressor03-06-15 
22-06-141277118801HTC 60 rpm 250 bhp
20" & 35" x 33½"
Vestey Brothers
for Nanking, China
Direct coupled to 15½" x 30" ammonia compressor - 150 bhp.
100 bhp by belt from flywheel
14-12-15 
22-06-141277318803HTC 60 rpm 150 bhp
16" & 30" x 27½"
Vestey Brothers
for Auckland, New Zealand
Direct coupled to 15½" x 30" ammonia compressor28-09-15 
30-06-141279718827HTC 200 rpm 220 bhp
12" & 20" x 21"
Avon Rubber Co
Melksham, Wilts
Driving by ropes
Flywheel grooved for 6 x 1½" dia ropes
30-07-15 
15-07-141280618836HTC 155 rpm 600 bhp
16¾" & 29¼" x 30"
Theodore Kipp & Co
Winnipeg, Canada
Driving flour mill by ropes
Flywheel grooved for 14 x 1½" dia ropes plus 175kW c/shaft generator
04-12-1424838
22-07-141281218842CC 155 rpm 570 IHP
17¾" & 29¼" x 30"
Denny Mott & Dickson
for Bangkok
(still at work mid-1990)
Driving teak sawmill by ropes
Flywheel grooved for 17 x 1¼" dia ropes
As at 2009 this engine still exists in Bangkok.
23-02-1524790
12-08-141283518865HTC 120 rpm 210/250 bhp
14" & 23" x 24"
Golden Valley Ochre Co Ltd
Bristol
Driving factory by ropes
Flywheel grooved for 6 x 2" dia ropes.
09-12-1424823
14-08-141283918869HTC 140 rpm 550 bhp
17¾" & 29¼" x 30"
Saxby & Farmer Ltd
Chippenham, Wilts.
Driving factory by ropes
Flywheel grooved for 12 x 1¼" dia ropes.
Plus crankshaft generator - 220kW Crompton
24-04-1524908
17-08-141284318873HTC 135 rpm
20" & 32¾" x 33½"
Lusty & Sons
Bromley-by-Bow, London
Driving woodworking machines by ropes
Two flywheels grooved for 9 x 1¾" dia ropes and 7 x 2" dia ropes.
??-05-1525365
05-08-141284518875HTC 175 rpm 435 IHP
15¼" & 25" x 27½"
Chesham Electric Light & Power Co
Chesham, Bucks.
Driving ECC generator by extension of crankshaft04-05-1524906
16-10-141287218902HTC 60 rpm
20" & 35" x 33½"
Vestey Brothers
for Madagascar
Driving ammonia compressor
(Engine built to O/No 12767 used for this order)
17-11-14 
16-11-141288718917HTC 60 rpm 150 bhp
16" & 30" x 27½"
Vestey Brothers
for Whangarei, New Zealand
Driving ammonia compressor
(Engine built to O/No 12769 used for this order)
29-12-14 
15-04-151297419004HTC 60 rpm 150 bhp
16" & 30" x 27½"
Vestey Brothers
for Auckland, New Zealand - with O/No 12773 (identical unit)
(but order book says sent to Nanking)
Direct coupled to 15½" x 30" ammonia compressor  
26-05-151301519045HTC 130 rpm 375/475 IHP
16" & 26½" x 27½"
Redlers Limited
Gloucester
Rope drive to factory
16 x 1½" dia ropes
11-02-1625327
08-06-151302219052HTC 60 rpm 150 bhp
16" & 30" x 27½"
Vestey Brothers
for Harbin, China
Direct coupled to 15½" x 30" ammonia compressor05-05-16 
06-07-151305519085HTC 60 rpm 250 bhp
20" & 35" x 33½"
Vestey Brothers
replaces O/No 12771 (This order entered in book as Crankshaft & Flywheel for 33½ Lentz)
Direct coupled to 15½" x 30" ammonia compressor - 150 bhp.
100 bhp by belt from flywheel
14-12-15 
21-07-151307119101HTC 60 rpm 260 bhp
20" & 35" x 33½"
Vestey Brothers
for Port Darwin, Australia
Direct coupled to 17½" x 34" ammonia compressor12-12-16 
21-07-151307319103HTC 60 rpm 260 bhp
20" & 35" x 33½"
Vestey Brothers
for Harbin, China
Direct coupled to 17½" x 34" ammonia compressor13-12-18 
29-07-151307919109CC 56/60 rpm
19" & 35" x 30"
Linde British Refrigeration Co
for Wildridge & Sinclair, Christchurch, New Zealand
Direct coupled to two 15½" x 30" ammonia compressors02-06-16 
29-07-151308019110CC 56/60 rpm
19" & 35" x 30"
As aboveAs above
(identical to O/No 13079)
24-07-16 
18-08-151308819118HTC 80 rpm 105 bhp
13" & 21½" x 24"
Linde British Refrigeration Co
for Liverpool
Direct coupled to 13¼" x 23" ammonia compressor30-06-16 
09-09-151310019130HTC 140 rpm 250kW
15¼" & 26½" x 27½"
Avon Rubber Co
Melksham, Wilts
Crankshaft generator (Crompton)07-07-1625485
26-10-151312819158HTC 60 rpm 260 bhp
20" & 35" x 33½"
Vestey Brothers
for Nanking, China
Direct coupled to 15½" x 30" ammonia compressor26-06-16 
11-11-151314117668HTC 160-170 rpm 114kW
12" & 20" x 21"
Vestey Brothers
for Hankow, China
Crankshaft generator
(This engine is No 17668 rebuilt)
23-03-16 
14-03-161316019190HTC 145 rpm 350kW
17¾" & 29¼" x 30"
J S Fry & Son Ltd
Bristol (No 7 factory)
Crankshaft generator (Crompton)31-10-1625775
14-03-161316119191As aboveAs aboveAs above03-03-1725775
14-12-151316819198HTC 170 rpm 140 IHP
10½" & 17" x 18"
Bath & Portland Stone Firms Ltd
for Weymouth, Dorset
Ropes driving factory
9 x 1½" dia ropes
16-07-1825578
25621
25-07-161332919359HTC 170 rpm 210 IHP
11½" & 18½" x 21"
Avon Rubber Co
Melksham, Wilts
Gear drive to rubber processing machinery.
(Spur gear on extended crankshaft)
19-10-1826483
31-08-161337319403HTC 200 rpm 160kW
12" & 20" x 21"
Cox & Co (Engineers) Ltd
Falmouth, Cornwall
Crankshaft generator08-08-1726385
22-03-171353719567HTC 195 rpm 200 bhp
11¼" & 18½" x 21"
Electrical Manufacturers Co
for Russia
Crankshaft generator - Bruce Peebles (supplied by client).
(Used for educational purposes)
 26504
28-08-181381719847HTC 145 rpm 500kW
20" & 32¾" x 33½"
Colchester Corporation
(S/H to Wallpaper Mfgrs Co, Darwen, Lancs - Hollins Paper Mill)
Crankshaft generator (Crompton).
For power station.
One source suggests that at Hollins Mill this engine drove line shafting for driving the pulpers and refiners.
08-09-19 
07-02-191387819908HTC 110 rpm 600kW
21½" & 37½" x 36"
(Order book says 17¾" & 29¼" x 36")
Douglas Brothers
Bristol
Crankshaft generator -"Witton" open multi-polar DC generator, 100kW, 220V.14-09-2027313
07-02-191389319923CT 150 rpm 880kW
17¾" & 29¼" x 30"
J M V Money Kent
for Cape Copper Co, India. ("now at Chasnalla Colliery - 1938")
Driving crankshaft generator - Dick Kerr alternator - 40 pole, 880kW, 3300V, 50HZ, 3 phase 27114
18-02-191389819928HTC 80 rpm 102 bhp
13" & 21½" x 24"
Lightfoot Refrigeration Co
for Drogheda
Direct coupled to 13½" x 23" ammonia compressor15-10-1927072
19-02-191390019930As aboveAs above
(Either this or above engine S/H to Rye Eng Co, High Wycombe 01-05-35)
As above
Repeat of order No 13898
29-08-1927072
18-02-191390319933HTC 160 rpm 200kW
14" & 23" x 24"
Co-op Wholesale Society
Wymondham, Norfolk
(No 1 engine)
Crankshaft generator - ECC alternator - 200kW, 440V, 40Hz, 3 phase07-01-2127270
15-04-191392819958CC 128 rpm 600 IHP
21½" & 35" x 33½"
Johnsons Smelting Co
West Bromwich, Staffs.
Ropes driving rolling mill.
14 x 2" dia ropes to 21 foot dia wheel on mill shaft.
09-06-22
to
12-06-22
27480
04-09-191406520095HTC 150 rpm 300kW
16" & 26½" x 27½"
John Berry & Sons
Ashburton, Devon
Crankshaft generator
(Generator supplied under separate contract.
28-01-2127714
13-11-191411720147HTC 160 rpm 200 bhp
12" & 20" x 21"
R H Stotesbury
for Holloway Brothers Ltd, (Clothing Manufacturers)
Stroud, Glos.
Ropes driving dynamo to produce power for DC motors driving factory machinery.
11 x 1¼" dia ropes.
Steam from 14' long x 8' dia Paxman Economic boiler, No 20148, rated 180 psi.
Engine was stopped in 1962 and scrapped in either the last half of 1974 or the first half of 1975.
08-09-21 
22-03-201432920359HTC 125 rpm 500 IHP
17¾" & 29¼" x 30"
Swadeshi Felt Caps & Hosiery Mfg Co Ltd
Hawa, India
(order cancelled but engine built)
Ropes driving factory.
18 x 1½" dia ropes
 27585
30-03-201435220382HP Lentz cylinder
complete with valves & gearing
12" x 21" - same size as order No 12220
To be exhibited at the Royal Show, Darlington 18-06-20 
07-05-201439320423HTC 140 rpm 400 bhp
16" & 26½" x 27½"
Brangwin Clarke & Co Ltd
for Baroda, India
("now with Shri Dinesh Mills, Baroda")
Rope drive to textile mill -
14 x 1½" dia ropes
19-01-22 
20-05-201440120431CC 155 rpm 570 IHP
17¾" & 29¼" x 30"
James Murchie & Co
Bangkok, Thailand
Rope drive to factory -
7 x 1¾" dia ropes
21-06-2127847
24-08-201448720517CT 90 rpm 1,100 bhp
20" & 32¼" x 33½"
(Order book has LP cyl bore as 32¾")
Bechardas Spinning & Weaving Mills
Ahmedabad, India
Rope drive to textile mill -
22 x 1¾" dia ropes
09-12-2128378
28391
21-10-201452220552HTC 67 rpm 207 bhp
17¾" & 29¼" x 30"
Lightfoot Refrigeration Co
for North Road
Direct coupled to 17½" x 30" ammonia compressor11-11-21 
26-11-201453920569HTC 155 rpm 330 IHP
13" & 23" x 24"
Avon Rubber Co
Melksham, Wilts
Gear drive to rubber processing machinery.
(Spur gear on extended crankshaft)
22-02-2228027
15-02-211457220602HTC 130 rpm 200 bhp
14" & 23" x 24"
J King & Co
Canal Road, Kingsland, N London
Rope drive to factory -
11 x 1½" dia ropes
(later intended to drive dynamo from end of crankshaft.)
23-06-2228149
08-03-2114583 24" Paxman-Lentz model engine - made to MO 42763
To be electrically driven.
This order number covers all items to be prepared for the Royal Show at Derby, June/July 1921Demonstration model to show features of the Paxman-Lentz engine.
(Shown at Bath & West of England Show, Bristol, May/June 1921)
14-06-21 
06-06-211462720657HTC 85 rpm 600 IHP
21½" & 35½" x 36"
British Oil & Cake Mills
Greenock, Glasgow
Ropes drive to mills -
Flywheel grooved for 12 x 1¾" dia and 5 x 1.3/8" dia ropes. Also ropewheel for 15 x 1¾" dia ropes
10-01-2328621
28550
07-02-221476920799HTC 160 rpm 200kW
14" & 23" x 24"
Co-op Wholesale Society
Wymondham, Norfolk
(No 2 engine)
Crankshaft generator.
This engine is duplicate of O/No 13903
06-11-2228574
02-08-2315183 HTC 130-150 rpm 400kW
17¾" & 29¼" x 30"
British Empire Exhibition
Wembley
(engine built to O/No 14329 used)
Crankshaft generator - ECC DC generator 440V.07-03-24 
03-09-241550221532HTC 135 rpm 400 IHP
16" & 26½" x 27½"
Yorkshire Amalgamated Products Ltd
Conisbrough, Doncaster (Engine scrapped on site in 1950.)
Rope drive to brickworks -
14 x 1½" dia ropes.
29-12-2429877
31-12-241561021640HTC 105 rpm 600 bhp
20½" & 35½" x 36"
Sussex Brick & Estates Co
Warnham, Sussex
Rope drive to brickworks -
16 x 1¾" dia ropes and 5 x 1¼" dia ropes to dynamo.
08-04-2530075
10-03-251568421714SC 170 rpm 60 bhp
10" x 21"
Maidenhead Laundry
Maidenhead
Driving 40kW ECC generator by coupling outside outer bearing.01-08-2530184
18-05-251577821808HTC 160 rpm 426 IHP
15¼" & 25" x 27½"
Lightfoot Refrigeration Co
for Gladstone, Australia
Direct coupled to 18½" x 26" DA high speed ammonia compressor driven from outer end of crankshaft.04-09-25 
25-06-251583321863SC 200 rpm 60 bhp
10½" x 18"
Lightfoot Refrigeration Co
for Sydney, Australia
Direct coupled to 8½" x 13" DA ammonia compressor driven from outer end of crankshaft.30-09-25 
09-03-2616140Eng
15183
used
HTC 130 rpm 400 IHP
17¾" & 29¼" x 30"
Anglo Siam Corporation
Bangkok
Rope drive to factory -
Flywheel grooved for 18 x 5" circumference coir ropes.
26-06-2630786
30843
31-08-261632122351HTC 150 rpm 250 bhp
14" & 23" x 24"
Aylesford Pottery Co,
Aylesford, Kent.
Second-hand to J W Ward & Son Ltd (sawmill), Bourne End, near Hemel Hempstead, Herts.
At J W Ward, rope drive to General Electric (Schenectady, New York) 150kW alternator.
8' dia. flywheel grooved for 12 ropes but only 4 ropes used at Bourne.
Stopped 1980. Removed for private preservation in 1982. Seen stored outside in 1985. Scrapped c.1990.
30-11 to
02-12-26
 
12-05-271656922599SC 175 rpm 140 bhp
16" x 21"
Oceana Laundry Co
London
Rope drive to laundry -
Flywheel grooved for 6 x 1¼" dia ropes.
Ropewheel grooved for 9 x 1¼" dia ropes.
19-09-2731572
30-05-271658922619HTC 150 rpm 420 IHP
15¼" & 26½" x 27½"
Anglo Burma Rice Company
for Rangoon, Burma
Rope drive to factory -
16 x 2" dia ropes from ropewheels on extension shaft.
1930 - converted to drive ECC 305kW dynamo.
10-10-2731633
07-02-281681622846SC 190 rpm 100kW
14" x 18"
C & E Morton Ltd
for India
Driving 100kW Crompton-Parkinson DC generator via coupling outside outer bearing.13-08-28
to
15-08-28
32002
27-06-281695122981SC 190 rpm 125 bhp
14½" x 18"
J T Wade & Son
for J C Lane
Rope drive to factory -
Flywheel grooved for 10 x 1" dia ropes.
01-11-2932167
30-06-281695622986SC 180 rpm 120 bhp
15" x 18"
Maxwell Laundry
Long Lane, Bermondsey, London
Rope drive to laundry -
Flywheel grooved for 6 x 1½" dia ropes.
16-10-2932224
26-02-291716723197SC 180 rpm 135 bhp
15" x 18"
Wm Lusty & Sons Ltd
Upper North Street, Poplar, London
Rope drive to factory -
Ropewheel grooved for 8 x 1½" dia ropes.
02-07-2932708
32815
04-03-291717423204HTC 175 rpm 139 bhp
10½" & 17" x 18"
Anglo Burma Rice Company
for Rangoon, Burma
Rope drive to factory -
Flywheel grooved for 7 x 1¼" dia ropes.
30-05-2932682
25-04-291722423254SC 220 rpm 80 bhp
13" x 13" (SLV)
Lightfoot Refrigeration Co
for Wildridge & Sinclair, Sydney, Australia
Direct coupled to 8½" x 13" DA high speed ammonia compressor.
Driven from outer end of crankshaft.
19-08-29 
10-05-291723623266SC 200 rpm 100kW
17" x 18"
Maidenhead District Laundry
for Marlow, Bucks.
Driving 120kW Crompton DC generator via coupling outside outer bearing.03-02-3032829
33291
02-12-291739523425SC 250 rpm 83 bhp
12½" x 13"  (SLV)
Le Roi Dyers & Cleaners Ltd
Romford, Essex
Rope drive to alternator - 33 bhp - 4 x 1" dia ropes.
12" belt drive to laundry mainshaft - 50 bhp.
24-03-3033244
29-05-301756423594CC 80 rpm 500 bhp
21½" & 40" x 36"
Lightfoot Refrigeration Co
for Auckland, New Zealand
Direct coupled (vis-a-vis) to two 18" x 36" ammonia compressors.
Used at butter store.
29-10-30 
14-05-311777523805HTC 150 rpm 1,200 IHP
25" & 37½" x 33½"
"Special Lentz Engine"
Wallpaper Mfrs Ltd
Darwen. Lancashire - Hollins Paper Mills
Crankshaft alternator (BT-H).
Arranged to pass out up to 12,000 lbs/hr steam from receiver at 25 psi.
One source suggests that this engine drove an 800kW 440V DC generator by B-TH.
??-02-3234066
10-11-321801824048SC 180 rpm 120 bhp
15" x 18"
Maxwell Laundry
Long Lane, Bermondsey, London
Rope drive to laundry -
Flywheel grooved for 6 x 1½" dia ropes.
(Duplicate of O/No 16956)
31-03-3334628
20-08-341840924439SC 250 rpm 100 bhp
12" x 13"  (SLV)
Una Star Laundry LtdRope drive to laundry -
4 ropes from 2' 3" dia ropewheel to laundry mainshaft.
14-11-3435291

Conversions to Lentz Valve Gear

Between 1923 and 1936 Paxman carried out over thirty conversions to Lentz valve gear on other manufacturers' steam engines, as detailed in the table below. With very few exceptions the conversions were on engines located in South Wales, mainly in various Works of Richard Thomas & Co. The purpose of these conversions was to achieve more economical steam, and thus fuel, consumption. The table below was amended in February 2012 in the light of information on surviving Paxman General Arrangement (GA) drawings scanned by Mike Gipson for the Paxman archive (580 drawings in total). Reference numbers of relevant GA drawings have also been added.

Order
Date
Order
No
Customer DetailsDetails of Original EngineDetails of Conversion
11-08-2315189Richard Thomas & Co
Aber Works
"Lamberton Engine"
Horizontal Tandem Compound
22" & 50" x 54"
36-42 rpm
Engine may have been built by Lamberton of Coatbridge, Scotland
Provide new HP cylinder 22" x 54" to fit existing bedplate complete with Lentz inlet and exhaust valves. Paxman large gas engine governor used to control longitudinal position of camshaft to alter cut-off. This type of governor 'discarded' - not used again for conversion job.
GA Drawing - SW1
21-09-2315214Richard Thomas & Co
Aber Works
Llansamlet
"Nevill Engine"
Horizontal Compound
30" stroke
Engine may have been built by Nevill Foundry, Llanelly
Provide Lentz valves for HP cylinder - retain existing cylinder. Fit 7" Pickering governor, Renold chain driven, with safety stop gear.
"To be erected during Easter holidays 1924."
GA Drawing - SW26
26-02-2415353Richard Thomas & Co
Aber Works
"Nevill Engine"
as above
Provide Lentz valves for LP cylinder - retain existing cylinder.
29-10-2415557Richard Thomas & Co
Lydney Works
Vertical Compound
"No 1 Engine"
Provide Lentz steam and exhaust valves for existing LP cylinder. 6" safety stop gear.
29-10-2415558Richard Thomas & Co
Lydney Works
"No 2 Engine"
Horizontal Compound
20.5/16" & 34¾" x 54"
160 psi. 500° F
Provide Lentz valve gear for HP and LP cylinders. 5" Pickering governor with 6" safety stop gear.
GA Drawing - SW63
19-02-2515660Richard Thomas & Co
Cwmfelin Works
"No 5 Engine"
Horizontal Compound
29" & 50" x 54"
36 rpm
Provide Lentz valves and gear to both HP and LP cylinders. No governor supplied. 8" safety stop gear.
19-02-2515661Richard Thomas & Co
Cwmfelin Works
"No 6 Engine"
Horizontal Compound
29" & 56" x 54"
36 rpm
Exactly the same conversion as for No 5 engine above.
19-03-2515697Richard Thomas & Co
Grovesend Works
"Lower Mill Engine"
Horizontal Compound
24" & 46" x 48"
(LP bored 46.1/8")
36 rpm.   150 psi.
Provide new HP and LP cylinders complete with Lentz valves and gear. 6" Pickering governor, chain driven.
GA Drawing - SW141
19-03-2515698Richard Thomas & Co
Grovesend Works
"Upper Mill Engine"
Horizontal Compound
27.7/8" & 52" x 48"
(LP bored 52.1/8")
36 rpm.   150 psi.
Exactly the same conversion as for Lower Mill engine.
7" Pickering governor, chain driven.
Both Lower and Upper Mill conversions "to be completed in August holidays"
GA Drawing - SW143
19-03-2515699Richard Thomas & Co
Raven Works
"No 1 Engine"
Horizontal Compound
19" & ??" x 48"
38 rpm.
Provide Lentz valves and gear to HP cylinder.
"To be similar in every respect to No 1 Engine Lydney LP cylinder which is working satisfactorily". (Order No 15557)
03-04-2515718Richard Thomas & Co
Raven Works
Glanaman
"No 2 Engine"
Vertical Single Cylinder
46" x 54"
Provide Lentz valves and gear to single cylinder.
8" throttle valve - "Special".
GA Drawing - SW105
05-05-2515752Richard Thomas & Co
Ely Works, Llantrisant
"No 1 Engine"
Horizontal Compound
20.5/8" & ??" x 48"
Provide new HP cylinder with Lentz gear and convert existing cylinder to Lentz valves and gear.
Governor not fitted.
GA Drawing - SW153
29-05-2515792Richard Thomas & Co
Cynon Works, Aberdare
Horizontal Compound
24.7/16" & 44" x 48"
Provide Lentz valves and gear to both existing cylinders.
"Existing eccentrics used and rods altered locally to connect to our valve rod ends."
17-07-2515862Richard Thomas & Co
Lydney Works
"No 3 Engine"
Vertical Compound
??" & 50" x 48"
Provide new 50" diameter cylinder and piston with Lentz valves and gear.
No governor supplied.
"Engine to be handed to Paxman 6am 31-7-26 and to be ready Monday 9-8-26."
21-07-2515863Richard Thomas & Co
Cilfrew Works
Horizontal
36" x 48"
(HP bored 36¼")
36-40 rpm.   80 psi.
Provide new 36" diameter cylinder with Lentz valves and gear.
Governor: 5" Pickering - auto cut-off.
GA Drawing - SW226
04-08-2515883Richard Thomas & Co
per Satchell & Co
Cardonnel Works
Horizontal Side-by-Side Compound
26" & 50" x 48"
Provide new HP and LP cylinders complete with pistons, rods, backcovers and Paxman-Lentz gear for fixed cut-off. Also heavy plates for connecting to existing bedplate. Existing governor used with flexible driving wheel, sprocket and chain drive.
GA Drawing - SW234
30-11-2516056Richard Thomas & Co
Lydney Works
"No 2 Engine"
Horizontal Tandem Compound
20.5/16" & 34¾" x 54"
(Engine details as O/No 15558)
Provide new LP cylinder - 40" diameter, with piston, back cover and front cover.
Piston fitted with 3 Ramsbottom rings.
New front and back covers with studs to suit US metallic packings.
Cylinder to be best close grained cast iron.
Tested to 60 psi hydraulic at works.
21-01-2616091Richard Thomas & Co
Aber Works
"Lamberton Engine"
Horizontal Tandem Compound
22" & 50" x 54"
(Engine details as O/No 15189)
Provide Lentz valves and gear to convert LP cylinder to Paxman Lentz, "on same lines as Cwmfelin Nos 5 and 6".
15-02-2716468Llanelly Steel Co (1907) Ltd
Llanelly
Double cylinder rolling mill engine
39" (2) x 54"
80 rpm.   120 psi.
(Suspect this engine is new or rebuilt at builder's works i.e. has Lentz gear from new.)
Complete sets of valve gear - 4 valve boxes - 8 sets of valve gear.
Paxman-Lentz shaft governor to permit 3½% speed variation. Governor to cut-off 0 - 0.6 stroke.
"Client to machine bed for layshaft brackets to carry 3½" diameter layshaft."
GA Drawing - SW272
02-09-2716686Robert Millar & Sons
Montrose, Scotland
Horizontal Cross-Compound
12" & 21" x 32"
80 rpm.   140 psi.
Flywheel 11' 10¾" diameter.
Belt drive
Provide new HP and LP cylinders to dimensions shown, with Paxman-Lentz locomotive type valve boxes. Also tailrod crosshead for air pump drive. Supply one "Bull" open protected type compound DC generator developing 100kW at 480V at 750 rpm. Also intermediate shaft with balanced WI pulleys. Rhodesian Railway valve boxes used (LP cylinder).
New governor fitted.
GA Drawing - SW321.
16-04-2816890Messrs Nevill & Son
for Richard Thomas & Co
Cwmfelin Works
"No 4 Engine"
Horizontal Compound
24" & 46" x 48"
52 rpm.   150 psi.
Provide new HP and LP cylinders. Lentz gear and cages on HP cylinder; locomotive gear on LP cylinder. Also covers and packings.
Existing throttle governor used.
6" safety stop gear.
17-09-2917344Richard Thomas & Co
Cwmfelin Works
"No 2 Engine"
Compound
36 rpm   150 psi.
Provide Lentz valves and gear - fit to existing cylinders "on same lines as for Cwmfelin Nos 5 & 6 engines.
Existing throttle governor.
07-11-2917390Richard Thomas & Co
Edlogan Works
Horizontal Tandem Compound
18" & 34" x 48"
40 rpm   150 psi - 150° S/H
(Later 175 psi ?)
Provide new HP and LP cylinders, both with locomotive type valve gear. Fit new pistons to existing rods.
Existing 5" throttle valve.
6" safety stop gear.
"Same valves and gear as Cwmfelin No 4 - drive altered."
GA Drawing - SW387
10-03-3117740Llanelly Foundry & Engineering Co
for Western Tinplate Works, Llanelly
Vertical Compound
23½" & 42" x 54"
35 rpm.   150 psi. 100° superheat
Provide locomotive valve gear and cages for existing HP cylinder and new LP cylinder with locomotive valve gear (cast with cylinder for LP).
Fitted 6" Hollingdrake governor.
"We guarantee that, provided engine supplied with same quality of steam as heretofore, and same quality of coal burned, to effect an economy of 7 tons of coal per week."
GA Drawing - SW413
07-04-3117752Richard Thomas & Co
for Eagle Tinplate Works, Llanelly (per Nevill)
Single Cylinder ?
21" x 48"
36 rpm   150 psi - 100° superheat
Provide valve box with 4 valve bonnets with gear complete up to and including eccentric and rod.
"Cylinder will be cast by Messrs Nevill."
??-??-??MO 6743British Xylonite Co
Brantham
Manningtree
Essex
"Easton, Anderson Engine"
Engine No 7020
Horizontal Compound
13½" & ??" x ??"
Alteration of valve gear on HP cylinder.
Although drawing SW421 shows a Reference No. 18150, in the surviving copy order book this relates to an Economic boiler, not to this conversion. The MO number on the drawing may refer to a Maintenance Order.
GA Drawings - SW420 and SW421, the latter dated 6th August 1931.
08-04-3217932Fairwood Tinplate Co Ltd
Fairwood Tinplate Works
Horizontal Compound
26" & 48" x 48"
36 rpm   160 psi
Provide new HP and LP cylinders, both with locomotive type gear, new pistons and rods.
6" Hollingdrake governor.
"Guarantee to give 750 IHP at 160 psi with a saving of steam coal of 12-15% present consumption … or that steam consumption will not exceed 10.5 lbs steam/IHP."
GA Drawing - SW448
01-08-3318157Ordered by:
Grovesend Steel & Tinplate Co
Sent to:
Duffryn Steel & Tinplate Co
"No 1 Mill Engine"
Horizontal Cross-Compound
28" & 52½" x 60"
36 rpm   160 psi. 80° superheat
(Engine built by Messrs Fullerton, Hodgart & Barclay, Paisley)
Provide new HP and LP cylinders with new pistons and rods and 2 new cast steel crossheads.
7" Hollingdrake governor & 7" safety stop gear.
"Probably be erected in Xmas stoppage."
"Provide one skilled erector to take full responsibility for re-erection of engine and running for one week, or until such time as guaranteed coal consumption of 31 lbs per box of 108 lbs substance is obtained."
GA Drawing - SW474
08-02-3418260Partridge, Jones & John Paton Ltd
Pontymister
Horizontal Tandem Compound
24" & 40" x 60"
36 rpm   150 psi.
Provide HP and LP cylinders with pistons, distance pieces, covers, all valve gear, steam and receiver pipes.
Existing governor and piston rod to be used.
GA Drawing - SW481
25-06-3518698Eaglebush Tinplate Works Ltd
Eagle Mill
"No 1 Engine"
Horizontal Cross-Compound
28" & 52" x 48"
36 rpm   160 psi.
Superheat to 500° F
Provide HP and LP cylinders with pistons and rods.
Lentz metallic packings throughout.
Provide heavy cast iron adapter for front of bedplate.
"The design to be generally along the lines of the mill engine at Duffryn Works (O/No 18157)."
8" Hollingdrake governor.
"Essential change-over takes place in Xmas holidays 1935."
GA Drawing - SW512
25-06-3518699Eaglebush Tinplate Works Ltd
Eagle Mill
"No 2 Engine"
Horizontal Tandem Compound
28" & 52" x 48"
36 rpm   160 psi.
Provide new HP and LP cylinders with valves, pistons and rods. Lentz metallic packings.
8" throttle valve governor.
"To be installed Easter 1936."
GA Drawing - SW532
19-12-3518878Redbrook Tinplate WorksHorizontal Tandem Compound
16" & 30" x 48"
140 psi.
Provide new HP and LP cylinders, pistons, rods and Lentz packings.
New connecting rod, crosshead and pin.
"To be installed during August holiday 1936."
GA Drawing - SW536
23-03-3618935Partridge, Jones & John Paton Ltd
Osborne Mills
Pontypool
Vertical Single Cylinder
46" x 42"
Provide new LP cylinder with piston, rod, top cover, bottom packing box (Lentz split metallic packing).
"Complete with locomotive type valvebox or locomotive valve chambers embodied in cylinder at our option."
6" Pickering governor - belt drive.
Skim up crankshaft and fit new phosphor-bronze bearings (ex-Llanelly Foundry & Engineering Co).
New forged steel crosshead.
4 cast iron motion bars.
GA Drawing - SW558
09-09-3619032Partridge, Jones & John Paton Ltd"Marine Engine"
Horizontal Compound
23" & ??" x 42"
120 psi at stop valve.
Existing HP cylinder to be sent to Paxman Works to be fitted with new seatings, valves and bonnets.
New layshaft, eccentrics, and layshaft coupling.
* New connecting rod (marine big end).
* New bedplate - top guides to be utilised.
* New mild steel crosshead and slippers.
Re-bore cylinder from 23" to 23½" - fit new piston and rod.
* - to be obtained locally.
GA Drawing - SW572
Notes

Marriage's East Anglia Mills at Felixstowe1.   Engine No 12874 was installed in Marriage's new 'East Anglia Flour Mills' at Felixstowe Dock, Suffolk. Preparation of the site commenced in 1905 and the new mill was completed in 1907.

Right: Marriage's East Anglia Mills at Felixstowe Dock.

A history of the business (a) published in 1940 contains the following: "The engine house, together with its equipment, constitutes one of the most interesting features of the mill. The main engine - a Paxman Lenz tandem compound engine - was built and supplied by Messrs. Davey, Paxman & Co. Ltd., of Colchester. This engine, after thirty-three years of continuous service, has maintained its efficiency to a remarkable degree. The auxiliary plant consists of a Browett Lindley vertical compound engine, direct coupled to an electrical generator, and a Mather & Platt automatic fire pump."

Engine House at East Anglia Mills
The Engine House at East Anglia Mills with the Paxman-Lentz to the right of the picture.

In 1940 a British bomber returning from France crashed into the mill which exploded in flames. A large part of the mill was demolished and it was out of action for two years. It may be that the disaster resulted in the Paxman-Lentz engine being damaged beyond repair. The mill closed in 2005 and was demolished in 2007.

a. The Annals of One Hundred Years of Flour Milling published by E Marriage & Son Ltd of Colchester and Felixstowe (there is no indication of authorship). Printed by Spottiswoode, Ballantyne & Co, Ltd. of Colchester, London and Eton. From the text it is clear the book was published in 1940.


Bibliography
1.Catalogue Illustré des Machines à Vapeur "Paxman," à Grandes Vitesses, À Distribution par Soupapes Accompagnées, Système "Lentz." Paxman-Lentz French catalogue - Publication No 204.
2. Paxman-Lentz Steam Engines, Davey, Paxman & Co Ltd catalogue - Publication No 723, dated May 1915.
3. Paxman-Lentz Steam Engines, Davey, Paxman & Co Ltd catalogue - Publication No 838. Undated but circa 1920/21.

Page updated: 01 MAR 2012