Paxman Portable Steam Engines, &C.
Catalogue No. 700A - December 1913
This page reproduces, with a few minor amendments and omissions, the text of Paxman's December 1913 catalogue of its Portable Steam Engines. At that time the company offered a number of variants, each in a range of power outputs. The types advertised were: single cylinder, double cylinder (equal sized cylinders each operating at the same steam pressure), log-burning, straw-burning, semi-portable and compound. Catalogue 700A also gives brief details of the Company's traction engines.
More information on Paxman portables is be found on the page Surviving Paxman Portable Steam Engines and the various pages linked from it.
No.700A
Portable
Steam Engines, &c.
Manufactured by
Davey, Paxman & Co., Ltd.
COLCHESTER, England.
| London Office : 78 QUEEN VICTORIA STREET, E.C. Telegraphic Address: "PAXMAN, CANNON, LONDON." Telephone: No. 697 Bank. |
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.
DECEMBER, 1913
The Best Engine.
AMONGST the numerous and important awards which we have received for the general excellence and economical working of our manufactures, the prizes received from the Royal Agricultural Society of England take a high place. As evidence of the extreme economy obtainable with Portable Engines, we give below an extract from the Judges' Report on the results of the last great Competitive Trials held by the Royal Agricultural Society, which were open to all makers of portable engines :-
"The Trials commenced on Tuesday, the 5th July, the first engine got into position being Davey, Paxman & Company's 8 H.P. Single-Cylinder Portable. This engine was run at 132 revolutions and a pressure of 105-lbs., with a brake load of 17 horse-power. It ran for 4 hrs. 23 mins. of actual time, with a supply of 193-lbs. of coal, equivalent to a consumption of 2.6-lbs. of coal per horse-power per hour, beating the previous best Cardiff record of 2.79-lbs., and thus early leading everyone interested in the trials to anticipate some remarkable results when the Compound Engines should make their appearance.
There is little to say about the general behaviour of the Davey Paxman simple engine during its trial. The steam pressure and speed hardly varied at all from start to finish, while the engine ran quietly and smoothly, requiring very little attention, the lubrication being, for the most part, automatic, and the governor controlling the speed absolutely.
The Compound Portable Engine (8 H.P.) which came to the brake on the 8th July, naturally excited much interest and attention, after the exceptional performance of the Paxman simple engine.
The two engines differ from each other materially in construction. In the former, the various parts of the engine are fixed to the boiler in the usual way, while in the latter these parts are carried upon a wrought-iron 'bed-plate,' which is entirely independent of the boiler except for its support.
The engine was run at 134 revolutions, with a pressure of 150-lbs., and a brake load of 20 horse-power. Nothing worthy of remark occurred during the trial run, which was characterised by perfect smoothness of working, and great regularity of speed, the governor having perfect control of the engine.
Quite a crowd of experts and others interested in the competition filled the shed towards the end of this trial, when, amidst some excitement, it began to be understood that the run would undoubtedly prove a phenomenal one. At the end of the prescribed four hours, and doing a duty of twenty horses, only 168-lbs. of coal had been called for, while, on the coal supply being stopped, and none of the ashes yet used, it was evident that the 'run down' would be a long one. Finally the engine was stopped at 4 hrs. 28 mins. actual, and 4 hrs. 39¾ mins. mechanical time, the coal used being 168-lbs., equal to a consumption of only 1.85-lbs. of coal per horse-power per hour.
As the result of these trials, the Judges awarded the prize of £200 to Davey, Paxman & Co. Ltd., for the Compound Portable Engine, and the prize of £100 to the same firm for their Simple Portable Engine."
(NOTE: The trials referred to above were those held during the Royal Agricultural Show at Newcastle upon Tyne in 1887.)
Paxman Portable Engine, Single Cylinder.
Paxman Portable Engines.
The well-known type of Portable Engine on four travelling wheels is probably (with the exception of the Locomotive) the best known and most widely used engine in the world. Of substantial design and construction, with a minimum of working parts, and so simple that no skilled attention is required for its management, the Portable Engine is eminently adapted for the many and varying purposes to which it is put, such as pioneer work in the "bush" in countries where roads, good or bad, are practically non-existent, for driving thrashing machines and agricultural machinery generally, for pumping purposes, for portable electric-lighting plants, for contractors and general construction work. A great feature in its favour is the fact that owing to the demand for the standard type of Portable Engine, delivery can generally be obtained from stock.
In the case of our single-cylinder type, the engine-work is mounted on the top of the boiler, the cylinder being bolted to a mild or cast-steel seating riveted to the boiler shell. The crankshaft bearings are carried on mild steel-plate brackets riveted to the boiler barrel in such a manner that the boiler is relieved of any undue strain, thereby lengthening its life, and the objectionable practice of bolt holes passing through the boiler plates is entirely avoided. Another great advantage is that the engine can be taken off the boiler and shipped separately, thus considerably reducing the cost of freight, and facilitating transport over difficult country. The mounting of the engine at destination is an easy matter, there being only two small joints to make for the steam and water connections, and a few bolts to be put in.
Our single-cylinder portable engines are now made suitable for a working pressure of 120 lb. per square inch, instead of the usual 100 lb., with a proportionate increase in the power developed.
We have received numerous and important awards for the excellent construction and economical working of our portable and other engines, and would parlicularly draw our customers' attention to the results of the last competitive trials open to all makers held by the Royal Agricultural Society at Newcastle-on-Tyne, quoted on page 3, when we obtained the only prizes offered, viz., the £200 prize for the best compound and the £100 prize for the best single-cylinder portable engine. After exhaustive trials carried out by the Society of Arts, we were also awarded the only Gold Medal for steam engines and boilers.
Both engine work and boilers are constructed with the greatest care, of the best quality material, they are equal in finish to the best classes of fixed and locomotive steam engines, and our engines can be seen working in practically every country in the world.
Cylinder. The cylinder is jacketed, and cast complete with steam chest. A truly-bored liner, of specially hard cold blast iron is forced into the cylinder case, forming a durable working barrel for the piston. The port areas are large, so that the steam generated in the boiler is admitted to the cylinder at nearly full boiler pressure, without wire-drawing and consequent loss of power. The cylinder is bolted to a seating riveted to the boiler barrel, and the lubrication is effected by means of an efficient lubricator. An automatic sight-feed lubricator can be supplied for the cylinder if required at an extra charge.
Piston. The Piston is of an improved type, fitted with metallic expansion rings.
Bored Guide. The crosshead runs in a circular guide, in place of the old system of flat slide bars.
Crosshead and Piston Rod are of steel, and the former is fitted with adjustable slippers to fit the bored guide.
Variable Expansion Eccentric. The slide-valve eccentric sheave is adjustable, and the cut-off may be varied between one-quarter an five-eighths of the stroke, in proportion to the power required from the engine, thus effecting a notable economy in the quantity of steam used. This adjustable sheave also permits the direction of rotation to be reversed. The speed of the engine is controlled by our improved throttle governor, which is so arranged that the steam distribution obtained is very similar to that of an ordinary automatic expansion gear.
Direction Of Rotation. The direction of rotation of all our single-cylinder and double-cylinder portable engines is anti-clockwise, looking at the pump side ; in the case of all semi-portable engines and compound portable engines, it is "clockwise," unless of course it is otherwise desired.
Connecting Rod. Gun-metal bearings are fitted to the connecting rod, held in place by straps of ample cross-sectional area to safely withstand the working strains of the engine. Adjusting cotters are provided, so that the wear can be taken up from time to time.
Crankshaft. The Crankshaft is of mild steel, drawn from the solid bloom, and bent into the required shape by powerful hydraulic machinery, which compresses the material together as it is bent, and produces forgings of the greatest strength. The crankshaft is long enough to take a pulley on the side opposite to the flywheel.
Crankshaft Brackets. Crankshaft brackets are made of mild steel plates, firmly riveted to the barrel, and having a large bearing surface upon the boiler. Heavy cast-iron plummer blocks are provided, fitted with adjustable gun-metal bearings, having ample wearing surface, the lubrication being automatic, by means of chains running in an oil bath. The plummer blocks are connected to the cylinder by longitudinal stay rods, turned and polished. The bolt holes in the crankshaft brackets are of oval shape, to allow for the expansion of the boiler plates, which does away with a frequent cause of heated bearings.
Link-Motion Reversing Gear. When the engine is required for winding, hauling, or other work in which the direction of rotation has to be reversed frequently, it should be fitted with link-motion reversing gear.
Automatic Expansion Gear. Where very great economy is a desideratum on account of the high price of fuel, and where the load is a varying one, we recommend the adoption of the Paxman Automatic Expansion Gear, identical with that fitted to our portable engines which obtained the only prizes offered at the last Royal Agricultural Society's trials, previously referred to.
Feed Pump. The Feed Pump is of the Paxman single-acting type, fitted with brass valves and valve seats. It is simple in design, not liable to derangement, and a special cock is provided, enabling the pump to be entirely disconnected from the boiler ; by this means the valves can be cleaned whilst the engine is under steam.
Feed-Water Heater. This is arranged with combined nozzles, so that the return water from the pump, in passing back to the feed-water tank condenses a portion of the exhaust steam escaping from the engine, and raises the temperature of the feed water to the highest degree consistent with lifting same through the suction pipe to pump, and it is then passed into the boiler in a highly heated state. This arrangement effects a saving of coal, besides saving the boiler plates from the strain of unequal expansion set up when cold feed is forced into the boiler.
Lubrication. As in the case of all our engines, great care is bestowed upon the lubricating arrangements of our portables, enabling them to make long runs without the necessity of stopping to oil.
Boiler. The Boiler is of the locomotive multitubular type, constructed throughout of the best ductile mild steel. The edges of all plates are carefully machined, and all rivet holes are drilled in place. The boilers of the single-cylinder and double-cylinder portable engines are now made suitable for a working pressure of 120 lb. per square inch, without any extra charge, and they are of ample size for supplying the necessary steam for the engine. They are hydraulically tested before leaving the Works to a pressure of 220 lb. per square inch.
Firebox. We were the first firm to introduce the use of steel plates for fireboxes, and for many years we were the only makers following this practice. The life of these steel fireboxes is about three times that of those previously made in iron. Our present-day practice is the result of long years of experience, and we obtain a special ductile steel, having a very low percentage of carbon, with all the hardening carbon eliminated. This, combined with the very perfect system of machine flanging and annealing practised at our Works, enables us to supply fireboxes of superior quality, the life of which is considerably prolonged by the special selection and treatment they undergo in the hands of workmen trained to exercise every possible care throughout all the operations of manufacture.
Fusible Plug. A Fusible Plug of improved construction is fitted in the crown plate of every firebox, to guard against accident in the case low water.
Tubes. These are of the best materials and are fitted in the boiler on an improved principle, rendering them more durable, and less liable to breakage. The use of ferrules is entirely dispensed with, as these are unnecessary if the work is sound and properly fitted, our practice in this respect being now followed by the leading locomotive makers.
Blast Pipe. Blast Pipe to chimney, and cock, is provided for convenience in getting up steam.
Barrel. The Barrel of the boiler is lagged with non-conducting material, wood, and sheet-iron, and is neatly painted, lined out and varnished in the best style.
Testing. All our portable engines are most carefully tested under steam before leaving the Works, and a Certificate of Test is supplied, if required.
Travelling Wheels. The wrought-iron carriage and travelling wheels on which each engine is mounted are practically indestructible, and are very suitable for use in hot climates. Horse-pole, bullock-pole, or shafts for horses are provided at the option of the purchaser.
Packing. For short sea voyages to European and Mediterranean ports, our usual practice is to despatch portable engines mounted on their wheels, merely protecting the fittings, &c., by boarding. For long sea voyages, we dismount the engine work entirely from the boiler, packing the engine in separate cases to keep the weight of the individual lifts as low as possible so as to keep down the freight charges. For shipment to distant countries, we can also adopt another method, as shown on page 22, where will be seen an illustration of a portable engine completely packed in a single case, suitable for a long sea voyage, followed by a long journey by road. On arrival at the port of disembarkment, the case can be mounted on wheels, and transported inland by road, this method being found more convenient than our usual close packing, as it obviates the necessity of having the engines erected at port of arrival, as would be the case if the engines were dismantled and packed in different cases, and though the sea freight is heavier, this is frequently compensated for by the saving in the cost of erection.
Fittings and Mountings. Fittings and Mountings are of the best quality, and comprise : Starting valve, two safety valves, one set of water gauges, one set of test cocks, steam pressure gauge, steam whistle, lubricator for cylinder, large lubricators for wearing parts, cylinder drain cocks, pet cock on pump, blow-off cock, fusible plug, manhole, mudholes and their covers, one length chimney with wire spark arrester.
Accessories. The following accessories are also included in our price for the engine : Large waterproof cover, funnel for filling the boiler, tube brush and rod, firing tools, suction and delivery hose, skid and chain, tool box containing a complete set of spanners, oil can, spare gauge glasses and collars, and instruction book.
Spares for Abroad. The following are the spares which we recommend for engines exported to distant countries were replacements would be difficult to procure : 2 pair crankshaft bearing brasses; *1 pair brasses for large-end connecting rod; *1 pair brasses for small end of ditto; *1 pair eccentric straps for slide valve; 1 pair eccentric straps for pump; *2 piston rings; 1 set firebars; 6 gauge glasses; 12 indiarubber collars for ditto; 1 set pump valves; 1 pump plunger; 6 boiler tubes. In the case of items marked *, twice the quantity is required for double-cylinder engines.
NOTE. - The description and illustrations of our engines contained in this catalogue are liable to alteration from time to time in consequence of improvements which we are always striving to effect.
Special Equipment.
Enlarged firebox, colonial type
Specially long log-burning firebox, as illustrated on page 18
Step grate for burning sawdust mixed with wood, shavings, &c.
Injector and fittings
Hand feed pump
Link-motion reversing gear
Screw brake to hind wheels
Chimney lifter, with winding drum and wire rope, which is specially recommended for raising chimneys fitted with heavy spiral sparkcatcher
Spiral spark arrester as shown on page 28
Lever chimney lifter
Lagging top of firebox
Lever lifting chocks
Jet condenser and air pump
Tubular feed-water heater
Second flywheel
Cylinder drain pipes leading into ashpan
Driving pulley
Self-acting, condenser type, sight-feed lubricator for cylinder
Mechanical oil-pump lubricator for cylinder
Paxman Portable Engines. Single Cylinder.
| Nominal Horse Power | Brake Horse Power | Cylinder | Flywheel | ||||
|---|---|---|---|---|---|---|---|
| Economical Load | Max Cont Load | Diam. | Stroke | Diam. | Face | Speed rpm | |
| 2 | 4 | 5½ | 4¾" | 8" | 3' 6" | 4½" | 210 |
| 2½ | 6 | 8½ | 5¾" | 8½" | 3' 6" | 4½" | 200 |
| 3 | 8 | 11½ | 6½" | 10" | 4' 0" | 5" | 170 |
| 4 | 10 | 13½ | 7" | 12" | 4' 6" | 6" | 140 |
| 5 | 13 | 17 | 7¾" | 12" | 4' 6" | 6½" | 140 |
| 6 | 16 | 20 | 8¾" | 12" | 5' 0" | 6½" | 140 |
| 7 | 19 | 23 | 9¼" | 12" | 5' 0" | 7" | 140 |
| 8 | 22 | 27 | 10" | 12" | 5' 0" | 7½" | 140 |
| 10 | 28 | 35 | 11" | 14" | 5' 6" | 8" | 130 |
| 12 | 36 | 46 | 12" | 16" | 5' 9" | 9" | 125 |
The above range of engines comprise the following improvements, and others fully described on preceding pages :—
Working pressure, 120 lb. per square inch.
No bolt holes passing through boiler plates or consequent leakages.
Bored crosshead guide, retaining the oil.
Sensitive high-speed governor.
Feed-water heater.
Crankshaft bearings fitted with Paxman's improved system of self-oiling chain lubrication, as shown on page 9.
Variable expansion eccentric, by which means the cut-off may be varied to suit the load and the direction of rotation reversed.
Efficient sparkcatcher.
Full equipment, as mentioned on pages 6 to 13.
Paxman Portable Engines. Double Cylinder.
| Nominal Horse Power | Brake Horse Power | Cylinder | Flywheel | ||||
|---|---|---|---|---|---|---|---|
| Economical Load | Max Cont Load | Diam. | Stroke | Diam. | Face | Speed rpm | |
| 8 | 20 | 27 | 7" | 12" | 5' 0" | 7½" | 140 |
| 10 | 26 | 34 | 7¾" | 12" | 5' 0" | 8" | 140 |
| 12 | 32 | 40 | 8¾" | 12" | 5' 0" | 9" | 140 |
| 14 | 39 | 48 | 9¼" | 14" | 5' 6" | 9" | 125 |
| 16 | 46 | 56 | 10" | 14" | 5' 6" | 10" | 125 |
| 20 | 57 | 71 | 11" | 16" | 6' 0" | 11" | 115 |
| 25 | 72 | 90 | 12" | 18" | 6' 6" | 12" | 110 |
| 30 | 84 | 110 | 13" | 18" | 6' 6" | 14" | 110 |
The above range of engines comprise the following improvements, and others fully described on preceding pages :—
Working pressure, 120 lb. per square inch.
No bolt holes passing through boiler plates or consequent leakages.
Bored crosshead guide, retaining the oil.
Sensitive high-speed governor.
Feed-water heater.
Crankshaft bearings fitted with Paxman's improved system of self-oiling chain lubrication, as shown on page 9.
Variable expansion eccentrics, by which means the cut-off may be varied to suit the load and the direction of rotation reversed.
Efficient sparkcatcher.
Full equipment, as mentioned on pages 6 to 13.
Paxman Portable Engine with Log-Burning Firebox.
Log-Burning Portable Engines.
We illustrate on the opposite page (see above) our special log-burning portable engine, which is equipped with a specially long firebox for burning wood logs. These engines are made on exactly the same lines as the standard portable engines described on the preceding pages, the only special feature being this long firebox, which is of suitable size for taking logs from 3 to 4½ feet in length.
It will be recognised by every engineer at all conversant with boiler practice that this special form of locomotive type boiler is immeasurably superior to the circular boilers sometimes supplied by other firms for the same purpose, and we suggest a careful comparison of the b.h.p. given off, not merely the nominal horse-power, which is an antiquated term and rather misleading. The circular-firebox portable is far from being as efficient as the loco. type, for whereas the former will only give off from one and a half to twice the nominal horse-power as a maximum, our portable engines on loco. type boilers will give off more than three times the N.H.P. The circular-firebox boiler cannot be forced like the loco. type, and it is also very liable to prime.
The firehole is square, and of such a size as to easily admit large logs.
The travelling wheels and carriage upon which the engines are mounted are of wrought iron, practically indestructible, and very suitable for rough country.
The code word indicating this specially long log-burning firebox is Ablegentur, which should be added to the code word indicating the size of portable engine taken from the preceding tables.
Paxman Portable Engine,
Fitted with Head & Schemioth's Straw-Burning Apparatus.
Straw-Burning Portable Engines.
The illustration opposite (see above) shows a single-cylinder portable engine, equipped with Colonial size firebox and Head and Schemioth's straw-burning apparatus for feeding the straw automatically into the firebox. This type of engine is largely supplied to countries where straw, cotton stalks, reeds, etc., are plentiful, and can be used exclusively as fuel. The apparatus consists of a long feed trough in front of the firehole, and two rollers, the lower one of which is driven automatically by a belt from the engine crankshaft. A baffle plate is arranged inside the firebox to ensure perfect combustion of the straw, and to prevent the tubes becoming choked by particles of straw ; the baffle plate also prevents the possibility of cold air reaching the tubeplate. The ashpan is kept covered with water (by means of a pipe leading from the pump delivery) to extinguish sparks dropping through the grate, thus preventing the possibility of the surrounding straw being fired.
The type of spiral sparkcatcher, illustrated on page 20, is specially recommended for all portable engines intended for straw-burning, on account of its great efficiency. It is also advisable to have a special chimney lifter (with winding drum and wire rope) fitted, on account of the combined weight of chimney and sparkcatcher.
The engines can be used for burning coal, by fitting the ordinary firedoor and additional grate bars, which are included in our price. In countries where coal and wood are dear, and straw is a waste product, to be got rid of by some means or other, these straw-burning portable engines are unquestionably the best and most economical means of power for thrashing purposes. The feeding apparatus is automatic, and the stoking can be performed by one man. The consumption of straw is roughly three to four times the weight of coal.
Paxman Portable Engines.
Fitted with "Head & Schemioth's" Straw-burning Apparatus.
Single Cylinder.
| Nominal Horse Power | Brake Horse Power | Cylinder | Flywheel | ||||
|---|---|---|---|---|---|---|---|
| Economical Load | Max Cont Load | Diam. | Stroke | Diam. | Face | Speed rpm | |
| 4 | 9 | 12 | 7" | 12" | 4' 6" | 6" | 140 |
| 5 | 12 | 16 | 7¾" | 12" | 4' 6" | 6½" | 140 |
| 6 | 14 | 18 | 8¾" | 12" | 5' 0" | 6½" | 140 |
| 7 | 17 | 21 | 9¼" | 12" | 5' 0" | 7" | 140 |
| 8 | 20 | 24 | 10" | 12" | 5' 0" | 7½" | 140 |
| 10 | 25 | 32 | 11" | 14" | 5' 6" | 8" | 130 |
| 12 | 31 | 41 | 12" | 16" | 5' 9" | 9" | 125 |
The above range of engines comprise the following improvements, and others fully described on preceding pages :—
Working pressure, 120 lb. per square inch.
No bolt holes passing through boiler plates or consequent leakages.
Bored crosshead guide, retaining the oil.
Sensitive high-speed governor.
Feed-water heater.
Crankshaft bearings fitted with Paxman's improved system of self-oiling chain lubrication, as shown on page 9.
Variable expansion eccentric, by which means the cut-off may be varied to suit the load and the direction of rotation reversed.
Efficient sparkcatcher.
Full equipment, as mentioned on pages 6 to 13, and on page 21.
Paxman Semi-Portable Engines.
These semi-portable engines are in all respects similar in design and construction to the Portable type described in the preceding pages, with the exception that in lieu of travelling wheels and under-carriage, they are mounted on a cast-iron ash pan under the firebox, and on a tank base, serving as a feed-water tank, under the smokebox end of the engine. The fittings and mountings are the same as for the portable type with the exception that waterproof cover, funnel, lockchain and skid, box for tools are not supplied with semi-portable engines.
These engines are very compact, and easily set to work, no expensive chimney or foundation being required, as they can be set down on concrete or stones without brickwork. The length of fixed chimney included in our price for semi-portable engines is 12 feet, or if desired, a hinged portable engine chimney can be supplied.
For places where no skilled labour is available for erecting, and for abroad, this semi-portable type of engine is to be specially recommended ; and it is particularly suitable for export, possessing as it does many advantages in the way of price and simplicity over a stationary engine and separate boiler.
Our semi-portable engines are fitted with axle lugs and turnplates, so that by attaching wheels and undergear they can easily be converted into portable engines.
At an extra price, we can fit a copper coil in the tank base under the smokebox, through which the exhaust steam passes, heating the feed water to a very high degree but without allowing it to come into direct contact with the exhaust steam.
Paxman Semi-Portable Engine, Single Cylinder.
Paxman Semi-Portable Engines. Single Cylinder.
(Power outputs, dimensions and 'improvements' as for standard Single Cylinder Portables above.)
Paxman Semi-Portable Engines. Double Cylinder.
(Power outputs, dimensions and 'improvements' as for standard Double Cylinder Portables above.)
Compound Portable Engines.
The design of the Paxman compound portable engine, as will be seen from the illustration opposite (see below), is the ideal one for the high pressure at which these engines work, and is immensely superior to any other make of compound portable engine offered to the public. The engine, which is in all respects an independent engine built on a channel steel frame, similar to our "Colchester" type, is bolted to four steel brackets projecting from the boiler. It will be seen therefore that the boiler in this case simply supports the WEIGHT of the engine, and is in no way subjected to the working strains of the latter, a point of extreme importance when the high working pressure of the boiler is borne in mind. The engine may be removed from the boiler by simply unscrewing a few nuts, and can then be used separately as an ordinary horizontal fixed engine. For export, the packages can be considerably reduced by this means, which effects a great saving in the freight.
The compound type of portable is to be recommended wherever economy of fuel and water is of great importance ; in addition, the engine can be started in practically any position of the cranks. The cylinders are cast in one piece and each is provided with a separate steam chest and slide valve. The ratio of the cylinders is such that the work done by the engine is about equally divided between them.
Paxman's Automatic Expansion Gear is fitted to the high-pressure cylinder, ensuring a great economy in steam consumption.
The Boilers are of ample size, and suitable for a working pressure of 140 lb. per square inch. The construction is generally similar to those of the single-cylinder portable engines, as previously described.
Paxman Portable Engine, Compound.
Portable Engines. Compound.
| Nominal Horse Power | Brake Horse Power | Diameter of Cylinders | Stroke | Flywheel | ||||
|---|---|---|---|---|---|---|---|---|
| Econom'l Load | Maximum Load | High Pressure | Low Pressure | Diam. | Face | Speed rpm | ||
| 8 | 19 | 23 | 5½" | 9" | 14" | 5' 0" | 7" | 155 |
| 10 | 26 | 30 | 6½" | 10½" | 14" | 5' 0" | 8" | 155 |
| 12 | 30 | 35 | 7" | 11¼" | 14" | 5' 0" | 9" | 155 |
| 16 | 40 | 48 | 8" | 13" | 14" | 5' 6" | 10" | 155 |
| 20 | 50 | 60 | 9" | 14½" | 16" | 6' 0" | 11" | 135 |
| 25 | 65 | 78 | 10" | 16½" | 18" | 7' 0" | 12" | 120 |
| 30 | 75 | 90 | 11" | 17½" | 18" | 7' 0" | 14" | 120 |
Semi-Portable Engines. Compound.
(Power outputs and dimensions as for standard Compound Portables above.)
Paxman Traction Engines.
The English design of Traction Engine is well known and its advantages in the way of efficiency and substantial construction fully recognised in all countries where this type of engine can be satisfactorily employed.
The Paxman Improved Traction Engines are distinguished for Great strength in all parts subjected to strain, most accurate workmanship, silent running on the road, extreme economy of fuel and absence of leakages, accessibility, the utmost efficiency, and great hauling capacity.
Boiler. The boiler is of the well-tried locomotive multitubular type, especially designed for quick steaming, of ample capacity, and great strength. It is stayed in a similar manner to the best railway locomotive practice. Every boiler is tested under steam to its working pressure of 160 lb. per square inch, and is tested by hydraulic pressure to 260 lb. The boiler barrel, smokebox and smokebox tubeplate are of the best Siemens-Martin steel.
The smokebox is constructed independently of the boiler barrel, so that it can be readily removed when corroded. A brass plug with fusible metal centre is inserted in the firebox crown.
Cylinder. The cylinder is made of specially hard and close-grained cast-iron with the working barrel cast separately, and tightly forced into position by suitable means. The cylinder is bolted down to a planed seat riveted to the boiler barrel ; the steam inlet elbow is cast with the cylinder and bolted down to the same seat, a leaky joint at this point being thus obviated. The cylinder is efficiently steam-jacketed and drained, the passages conducting the steam from the boiler to the stop-valve are so arranged that only dry steam reaches the cylinder, and any tendency to prime is removed, The cylinder sides and top are coated with non-conducting composition and neatly lagged with sheet steel. Two gun-metal lubricators are provided, one for the stop-valve and one over the slide valve. A gun-metal stop-valve is arranged at the highest point in the cylinder.
Safety Valve. A double Ramsbottom safety valve is mounted on the top cover of the cylinder.
Slide Valve. The slide valve is of the "Trick" type, the great advantage of which is that a smaller movement is necessary to give a wide opening of the steam port, thereby decreasing the wear and tear of the slide valve and the valve face.
Trunk Guide. In lieu of the ordinary slide bars, a cylindrical trunk guide is employed, which is bored and faced at one setting, thus securing perfect alignment with the centre line of the cylinder. At one end the guide forms the front cylinder cover, the opposite end rests on the weighbar bracket bolted to a planed seat riveted to the boiler barrel, this seat being of the same height as the cylinder seat. The bored trunk carries a guide for the valve rod.
"Pickering" Governors are mounted on the top of the cylinder. The governor acts directly on to an equilibrium throttle valve within the cylinder, without the intervention of any levers or set screws liable to become lost or deranged in transit. A good feature of this governor allows of the speed of the engine to be increased or decreased within reasonable limits while the engine is running. This type of governor is practically perfect, and its working will be appreciated by all thrashing machine owners.
Crank, Countershaft and Axles are of the best mild steel and of great strength to withstand the wear and tear of road work. The side plates of the firebox shell are carried upward and backward for supporting the bearings for the shafts and main axle. The crankshaft carriages are let into bored recesses of the horn plates, and are fitted with adjustable gun-metal bearings and oil catchers. All the brackets are supplied with castellated nuts and split pins. The bearings for the countershaft and main axle are also turned to fit into bored holes in the horn plates, and bolted thereto with tightly fitting bolts, thus making a thoroughly reliable job. The horn plates are stiffened between with two flanged cross plates.
Gearing. The whole of the gearing including the compensating motion wheels are cast from machine-cut patterns, and are made of the best crucible cast-steel of great strength. The first-motion wheels are placed within the flanged box brackets between the bearings, by means of which a narrow engine is obtained, the gearing subjected to heavy work is more fairly worn and all serious overhanging strains are avoided. The fast and slow speed wheels are riveted together and slide in and out of gear on the square part of the countershaft. The use of feather keys let into the shaft or keys cut out of solid material are discarded, the square shaft being a far more satisfactory arrangement. One lever moves the wheels in or out of gear, and the driver cannot put one set of wheels into gear until the other is drawn out.
Compensating Gear. The compensating gear is fitted to the main axle, and allows the power to be transmitted through both the driving wheels when travelling in a straight course, or turning corners. Three pinions are adopted in the centre plate, and the plate is made of cast steel. The compensating gear can be locked when necessary.
Driving Wheels are each constructed of extra strong steel tee rings with mild steel cross strips, strong spokes and inside tyre plates, the whole riveted together by hydraulic pressure. The hind wheel bosses are fitted with nose caps over the axle ends for keeping the oil in and the dust out.
Brake. A strong strap brake, lined with hard wood blocks, is fitted to the main axie, which is capable of controlling the engine when descending steep gradients.
Winding Drum. A slip winding drum, having 50 yards of flexible steel wire rope, is mounted on the boss of the brake drum. The rope can be paid out as the engine travels forward, or when the engine has mounted a hill the drum can be set in motion for hauling the load up the incline. The drum is also useful for pulling a thrashing machine out of places inaccessible to the engine. Suitable guide rollers with steel brackets are fitted to the tender side, and the rollers are arranged so that the rope can be taken off at right angles in either direction, clear of the tender.
Feed Pump. An efficient eccentric-driven feed pump of ample capacity is provided, fitted with gun-metal gland, valves, and boxes. This pump is continuous in action, and is not liable to derangement. It is mounted on the hornplate inside the tender, close to the driver, making a very handy arrangement.
Water Lifter. A large steam water lifter, and 26 feet of wire-armoured suction hose with rose, is provided for filling the tank.
Fittings and Mountings are of solid type, mostly Dewrance's well-known high-class patterns, comprising Bourdon pressure gauge with syphon and cock, two sets of asbestos-packed water gauges, blow-off cock, blast tap and pipe to chimney, complete set of firebars, manhole lid and cross-bars, firedoor, mudhole covers and cross-bars, chimney, etc.
Lagging. The barrel is entirely covered with non-conducting composition, lagged with wood and sheet iron and secured by bands.
Painting. The engine and boiler, with the exception of the bright parts, are painted with three coats of good oil colours, lined and varnished.
Equipment. The engines are supplied with the following tools, etc. Three lamps, waterproof cover, complete set of spanners, adjustable spanner, hand hammer, chlsel, piston-ring clips, full set of firing tools consisting of fire shovel, clinker shovel, ash rake and poker, tube brush with rod, bucket, tundish, two oil bottles containing a supply of cylinder and lubricating oil, one oil can, a box of grease, assortment of packing for glands, waste, emery cloth, tank-measuring rod, indiarubber rings, two fusible plugs, two dozen assorted split pins, and one set of asbestos rings for mud-lids, one tool box, set of spuds for use on soft ground, frost spikes, Instruction Book and Summary of Traction Engine law.
Paxman Steam Tractor.
Our improved steam tractor is generally speaking a small traction engine in miniature. It is of the 3-shaft type, and built for running under the Local Government Board's Motor Regulations. The travelling speeds are 3 and 6 miles per hour respectively, and any speed between these two can be run if required.
The tractor is mounted on springs at the front and back end on an efficient plan. As a duplicate feed arrangement, an injector is added in addition to the ordinary feed pump. The engine is fitted with compensating gear, with three bevel pinions. A slip drum, with 50 yards of flexible steel wire rope, is provided. Steel gearing made from machine-cut iron patterns is used throughout. Many of the details are of cast-steel to reduce weight and avoid the possibility of breakages.
Two powerful block brakes act on the periphery of the driving wheels. The outfit consists of 3 lamps, a water lifter, and 25 feet of wire-armoured hose pipe, tools, a pipe from the safety valve to the chimney, waterproof cover, side plates for screening the working parts, horn alarm, etc.
The motor is suitable for dealing with loads of from 5 to 8 tons, or for driving a small thrashing machine.
Paxman Traction Engine.
General Purpose Traction Engines.
| Nominal Horse Power | Brake Horse Power | Cylinder | Flywheel | Speed | Driving Wheels | Weight empty (tons) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Diam. | Stroke | Diam. | Face | RPM | MPH | Diam. | Width | |||
| 4 | 16 | 6" | 9" | 2' 8" | 5" | 200 | 3 & 6 | 4' 6" | 10" | 4¼ |
| 5 | 28 | 8" | 10" | 3' 6" | 5" | 180 | 2 & 4 | 5' 6" | 1' 2" | 7¾ |
| 6 | 30 | 8" | 12" | 4' 6" | 6" | 155 | 2 & 4 | 6' 0" | 1' 4" | 9¼ |
| 7 | 35 | 8½" | 12" | 4' 6" | 6" | 155 | 2 & 4 | 6' 0" | 1' 5" | 9¾ |
| 8 | 40 | 9" | 12" | 4' 6" | 6½" | 155 | 2 & 4 | 6' 6" | 1' 6" | 10¾ |
| 10 | 50 | 10" | 12" | 4' 6" | 6½" | 155 | 2 & 4 | 6' 6" | 1' 6" | 11¼ |
Extra Equipment
Injector
Colonial firebox
Awning over tender only
Awning over the whole engine
Coal or wood rack
Tank under boiler barrel
Mounted on springs, complete
Mounted on springs, on hind axle only
Mounted on springs, on front axle only
Crane and gear, to lift from three to five tons
Page updated: 16 AUG 2008