Articles from 'The Engineer' magazine

The Engineer, 21st July, 1871.

The Royal Agricultural Society's Show at Wolverhampton

Messrs. Joseph Evans and Sons, of Wolverhampton, who exhibited for the first time, have made a very good beginning, and give promise of taking a very prominent position as pump manufacturers. Their 6 horsepower high pressure pumping engine has the pump and steam cylinder on the same bed plate. We will only remark that it is effective in design, and well and strongly made.

A bucket and plunger pump, No. 5592, to be driven by horse power, has one end of the connecting rod working the plunger, secured to the circumference of a disc; this not only simplifies the construction of the machine, but as it does away with all gearing, renders the machinery less liable to breakage in case the horse should prove restive. They also display a great many lift and force pumps of various descriptions, amongst which I may particularise No. 6617. This is a 4 inch rotary lift and force pump. A block on the crankshaft moves a long wrought iron link, up and down. The link is fixed at one side to an upright arm, attached to the pump barrel, and is left free at the other end, and to it is fastened the pump rod, the consequence of this arrangement being, that the return stroke, in which no labour is expended, is made very quickly.


The Engineer. 25th August, 1871.

Steam Pumping Engine, Messrs. J. Evans & Sons, Culwell Foundry, Wolverhampton

In the accompanying engraving we illustrate a neatly arranged pumping engine exhibited by Messrs. J. Evans and Sons at Wolverhampton, during the show.

The engine is six nominal horsepower, non-condensing, and is fitted with an 8 inch diameter cylinder, 16 inch stroke. The crankshaft carries a pinion 7 inches in diameter, working into a 28 inch spur wheel on the pump crank. The pump is double acting, bucket and plunger, 8 inches diameter, and the plunger is 5.625 inches diameter, with 10 inch stroke.

The valve on the bucket end of the plunger is of India-rubber, and in the form of a belt, which covers the ingress holes. In the forward stroke, the valve closes on the holes in the plunger, and in the backward stroke expands with the pressure of the water, passing through the holes to the front end of pump, thence to the delivery pipe.

The suction and delivery valves are of the ordinary flap kind, and the bucket is metallic, with a gun metal ring. The cranks, etc. are of best wrought scrap iron, and the piston rod and connecting pin of steel.

It is designed for supplying estates, mansions, public institutions, etc. and may be arranged for various heights for lifting and forcing water. By disconnecting the piston, the machinery may be used for any purpose to which an ordinary steam engine is applied. The workmanship is very good, and the same may be said of the design.


The Engineer. 28th July, 1876.

The Royal Agricultural Society's Show at Birmingham

In my notice of steam pumps last week, I omitted to refer to one which is novel, in the sense that it has not been exhibited before. This is the 'Reliable' steam pump, exhibited by Messrs. Joseph Evans & Sons of Wolverhampton. The most noteworthy feature about this pump is the fact that in lieu of ordinary clacks the pump is fitted with a slide valve. This valve is worked by an eccentric on the crankshaft, which shaft is driven by a dog link intervening between the steam and pump cylinders. The pump worked very well, and appears to be adapted for pumping thick fluids.


The Engineer. 22nd July, 1881.

Exhibits at the Royal Agricultural Society's Show, Derby

Messrs. J. Evans and Sons, of Wolverhampton, showed Tonkin's patent pump at work. This pump is another of the multitudinous class of steam pumps with steam moved valves, first invented about twenty years since. It is very silent and quiet in its action. They also exhibited some good rotary donkey pumps, coarse and strong, and well fitted for rough work.


The Engineer. 16th December, 1881.

The Cornish Steam Pump
Messrs. Joseph Evans & Sons, Wolverhampton, Engineers

The engraving illustrates a new type of steam pump, manufactured by Messrs. Joseph Evans and Sons, of Wolverhampton, and Queen Victoria Street, London.

Its Motion will be readily understood from the drawing. As the piston approaches the end of its stroke, say from right to left, the steam from the cylinder is admitted by the ports K and M to the left of the small plunger G, moving it to the right, by which means the right end of the large plunger D is placed in communication with the exhaust through the ports N, and the left end with the interior of the steam chest B, from which steam is admitted through the ports R and Q, causing the plunger D, together with the common slide valve F., to be carried over to the opposite end of the steam chest, thereby reversing the motion of the main piston; a similar motion takes place at the opposite end.

The cushioning of the plunger valves is most effectively performed by means of small ports, through which steam direct from the steam chest flows upon the end of the plunger towards the completion of its stroke, and this prevents it striking up the covers and caps; the exhaust steam from the plunger G passes through the small port S, and thence into the main exhaust through N. The steam chest being placed on the side of the cylinder, and the bottom of the steam port on the same level as the bottom of the cylinder, the whole of the condensed water is carried out at every stroke of the piston, whereby the necessity for drain cocks is avoided. This appears to be a simple and efficient pump, well adapted for doing a great deal of work under trying conditions. There are few parts to get out of order, and the whole machine will obviously stand knocking about without injury.


The Engineer. 20th May, 1892.

Letters to the Editor

Condenser Valves

Sir, In reading your very interesting article on condensers in the current issue of your paper, we notice a mention of some firms using valves with serrated edges. In fairness to ourselves, will you kindly mention that the serrated valves are our patent, and explain that the object of such serrations is to cause the valve rubber to partly rotate on the grating at each discharge, thus distributing the wear equally over the whole face. We send you a sample rubber, and you will notice that the serrations are diagonal, not parallel with the axis. This simple device prolongs the life of the rubber quite twice as long. The turning action also has the effect of sweeping off the face any foreign substance.

Wolverhampton, May 18th. Joseph Evans and Sons.


The Engineer. 7th October, 1892.

Compound Condensing Duplex Pumping Engines For The Water Supply of Managua, Nicaragua
Messrs. Joseph Evans & Sons, Wolverhampton. Engineers

The pumping engine illustrated above has been designed on the duplex principle, with Messrs. Joseph Evans and Sons' improvements. There are two 12 inch diameter high pressure, two 20 inch diameter low pressure steam cylinders, and two 12 inch diameter water cylinders, all 12 inch stroke. The lever motion for working the valve gear is fitted with telescopic pieces, having long bearing surfaces, which are readily oiled from a lubricator provided at the top of each. This arrangement dispenses with the usual radius links and pin joints, thus reducing the number of wearing parts. The steam cylinders throughout are lagged with sheet steel, packed with slag wool, and secured by brass bands, making a very neat and efficient covering. Cushioning valves are fitted to each cylinder, also a sight feed lubricator, and additional lubricators for the low pressure cylinders and stuffing sleeves. The water cylinders are fitted with easily removable barrels, secured in place by set screws, and are provided with deep buckets and cup leathers.

The water valves are of Evans' patent rotating disc type, with brass gratings and guards. The water from the delivery branch is passed through the tubes of a surface condenser. For convenience of space this latter is placed at right angles with the centre line of the main engine. The barrel of the condenser is of wrought iron, double riveted in the longitudinal seam, and doors of the full diameter of the condenser are provided at either end for access to the tubes. The exhausts from the low pressure cylinders are brought together by means of a forked piece, and led through a two way valve, the latter being provided for the purpose of turning the exhaust either to the atmosphere or to the condenser, as desired.

The air pumps are on Messrs. Evans' Cornish principle, with Tonkin's patent steam cylinders, each steam cylinder being 5 inches in diameter, and each air pump barrel 8 inches diameter, all 12 inch stroke. The air pump barrels are fitted with gun metal liners. The valves are on Messrs. Evans' patent rotating system. All valves are above the water cylinder, and the capacity is so adjusted that the water level does not fall below the top of the pistons, consequently a very efficient air pump is the result. Either one of the air pumps could on emergency do the work. The engines are capable of delivering over 50,000 gallons of water per hour. They have to draw their water from a lake l,000ft. distant, through a 12 inch diameter suction pipe, and deliver through 6,000ft. of 12 inch delivery pipe to the reservoir 180 feet above the pumps. The working steam pressure is 90 lb. per square inch. The engines were made for the Nicaragua Company, Leadenhall Street, London, E.C., under the supervision of Mr. Heber Duckham, A.M.I.C.E., and are for the extension of the water supply to the town of Managua.


The Enginer. 1st September, 1893.

Compound Duplex Pumping Engines
Messrs. Joseph Evans & Sons, Wolverhampton. Engineers

We illustrate above a pair of fine compound duplex pumping engines constructed by Messrs. Joseph Evans and Son, of Wolverhampton. The engines are tandem, and fitted with a condenser, not shown, on a lower level. The dotted lines show the exhaust pipe. As regards the main valve motion, we may mention that the high pressure cylinders are worked on the ordinary Tonkin's patent steam moved valve system, and the main internal steam plunger in the high pressure steam chest is fitted with a slide spindle, which drives the low pressure slide valve through an arrangement of compensating levers. The object of this lever motion is two-fold. In the first place, the low-pressure slide valve face stands out considerably farther from the centre line of the engine than the high pressure face, and the lever is a convenient method of bringing in the centres to suit. In the second place, the width of the ports and the travel of the valve is greater in the low pressure cylinders than in the high pressure, and it will be noticed that the horizontal vibrating lever is pivoted at the end nearest the centre of the engine, but the thrust is taken at an intermediate point between the pivot and the outer end; in other words, it is a lever of the second order.

It will be observed from the engraving that the steam chests are low down on the cylinders, and the bottom of the steam port is below the bottom of the cylinder in each case, the special object of this arrangement being to drain the cylinder through the exhaust without the necessity of drain cocks, and the arrangement which Messrs. Evans adopt entirely in their direct acting steam cylinders is found to answer admirably.

The crossover pipes on the high pressure steam cylinders are for the purpose of operating the slide valves so as to drive the duplex motion which is affected as follows:
Both sides of the engine travel together, but the left hand side is half the length of the stroke in advance of the right hand side, consequently one side of the engine only reverses itself at a time, the other side at the instant of it neighbour's reversal is in the centre of its travel and going at full velocity, hence the water column is kept in motion and there is no appreciable alteration in the flow of delivery. Should it happen from any cause that one side of the engine became disabled, the cross over pipes can be shut off by means of the cocks provided and shown outside the high pressure steam cylinders when the valve motion of each cylinder would be worked on its own account as an ordinary double action pump, the disabled half being meanwhile shut off both as regards the steam and water connections, suitable valves being provided for the purpose, and any repairs needed could be effected at once, while the remaining available half of the engine cou1d continue to work.

In the pumping engine under notice there are outside packed double-action rams, each 14 inches in diameter, with tail rods at the outer ends to equalise the displacement, and also to carry part of the weight of the rams. The water valves are of the patent rotating rubber disc type, working on brass gratings and the lift regulated by suitable saucer shaped guards. The rubber discs which are of special quality, arrived at after much experimenting, are serrated on the edges diagonally; the water in upward flow impinges on the diagonal serrations, and, on the reaction turbine principle, causes the rubbers to partly rotate on each beat, thereby equalising the wear all over the faces. It is stated that cases are known where, after being in wear for six or eight months, they have become reduced in thickness more than 50 percent, and yet perfectly even all over the face. A valve has been sent us by the makers which fully substantiates this statement. The centre boss of the valve guard fits in the centre hole of the rubber and forms a bush, thereby preventing the wear due to rotation coming on the rubber. A small amount of lift is allowed in the centre of the valve so that there may be free rotation.

Though not shown in the engraving, there are independent air pump condensers in connection with the engine. The condensers are placed on a lower level than the main engine bed, to give a good fall for the condensation water from the steam cylinders. The condensers are of the injection type, with a large condensing chamber. The air pump barrels are 10 inches in diameter by a 24 inch stroke, gun metal lined. The steam cylinders, which are on Tonkin's patent, direct acting system, are each 8 inches in diameter by a 24 inch stroke, and are carried on strong distance pieces overhung from the condenser ends. Convenient doors and covers are provided throughout to pumps, cylinders, condensers, etc. for ready access to the internal portions.

A substantial girder bed plate is provided under the steam cylinders and back pump boxes, the forward pump boxes being carried on box feet connected to the back portion by bridge pipes, which latter also serve to tie the pump together. Large air vessels are provided, and all details worked out to best advantage, so as to be as convenient as possible for underground use.

The pumps deliver about 1,400 gallons of water per minute, 360 feet high, with 80 lb. per square inch steam pressure. They are fitted in a large colliery in the Newcastle upon Tyne district where a number of large engines on the same principle, by Messrs. Evans, have been in successful operation for sometime past.


The Engineer. 10th January, 1896.

Letters to the Editor

Drowned Pumps

 It may be in the recollection of your readers that a few weeks ago the Dungannon collieries, Ireland, were suddenly inundated by an enormous body of water tapped from some old workings, and which unfortunately resulted in serious loss of life, besides overwhelming the pumping machinery.

Mr. Donald Munro, the managing engineer of the colliery, advises us that they have been able to start the large Cornish duplex steam pumping engine, supplied by us to the colliery, and that it is working 60 feet under water. We think this will be of interest to those who have to do with underground pumping machinery, and shows in a remarkable manner the capabilities of the direct-acting type of engine.

Joseph Evans & Sons, Wolverhampton. January 8th.


The Engineer. 16th April, 1897.

Letters to the Editor

Sir, If the notice you give of a pump regulator in your last week's issue is intended to bring before your readers a novelty, we would like to say that the same idea has been applied by us upwards of ten years ago on a pumping engine for Leamington Spa, and since then to engines for the Barry Dock, Vale of Leven, and Vale of Glamorgan Waterworks, etc. We claim to "go one better" also, as in addition to controlling the supply, we have provided for the bursting of the delivery main.

Joseph Evans & Sons, Wolverhampton. 7th April, 1897


The Engineer. 6th August, 1897.

Evans Pumping Engine

We illustrate a fine pumping engine for underground working, lately constructed by Messrs. Joseph Evans and Sons, of Wolverhampton, for use in the Miike coal mines in Japan. The engine, as will be seen by the illustration, is of the direct acting type, and consists of two complete compound engines, arranged side by side on bed plates, their steam distribution gear being so arranged that under ordinary conditions the two engines work together on the duplex principle, so as to keep up a continuous flow of water; but when desired the two sets of valve gear can be disconnected, and one of the engines can be kept at work while the other is at rest. The disconnection of the two sets of gear is effected entirely by the manipulation of certain stop valves, and is the work of a very short space of time.

The makers claim for this system that it gives practically the advantages of two engines, the working of the valve gear and the arrangements and strengths of the various parts of the pumps being such that if one engine is stopped for repairs or attention of any sort, the other engine may with safety be run for a time at a greatly increased speed, so that but little pumping capacity is lost until such time as the second engine can again be put into work. The principal dimensions of the engine are as follows:

High pressure steam cylinders, 24 inches diameter; low pressure ditto, 44 inches diameter; stroke, 36 inches. The duty for which the engine was designed is to raise 2,000 gallons of water per minute a height of 600 feet. The water to be dealt with is gritty and impregnated with sulphur, and in consequence is of a strongly corrosive nature, and with a view to resisting this corrosive action, the rams, rods, and other working portions of the pump are made of a specially resistant bronze.

The engine is provided with a surface condenser, having tubes and tube-plates of brass, the water raised by the pumps being employed as cooling water. The condenser is fitted with two independent air pumps of the direct acting type. The steam distribution valve gear of the engines and also of the air pumps is of the well known steam-moved type which Messrs. Evans have manufactured for many years past, the gear of the main engines being Evans and Tonkins' patent modified form of gear for enabling the pumps to work in duplex or independent of each other, as above described.

One steam relay drives both sets of slide valves on high and low pressure cylinders. The pump ends are provided with vacuum chambers on the suction inlets, as well as air vessels placed on the connecting pipes between the delivery valve boxes, and all the valve boxes are arranged so that they can be opened and the valves lifted quite clear of other parts of the machine. The pumps are of the externally-packed plunger type, and all parts of the pumps are arranged so as to be easily accessible.


The Engineer. 5th July, 1901.

Wire Rope Driven Treble Ram Pump

In the accompanying engravings we illustrate the latest design of triple ram pump made by Joseph Evans and Sons of Wolverhampton.

It is intended for high lift work in mines, etc. and is arranged to be driven direct by wire rope.

On the left is shown the whole pump; Fig.1 is a section through the valve boxes; and Fig. 2 a section of the rope wheel.

As will be seen, this rope wheel is not of the ordinary grooved type, but is fitted with a tread, and the driving rope goes round the rim one and a half times.

The pump is rated to deliver 18,000 gallons of water per hour against a head of 750 feet.

The general design will readily be seen from the illustrations.

The gearing between the rope pulley and the crank shaft is half shrouded.

The countershaft and crankshaft are of mild steel; the latter, which is provided with circular webs, being cut from the solid and carried in four pedestals fitted with gun metal bearings.

The connecting rods are of steel, fitted at the large ends with gun metal marine heads. The small ends are solid, and are provided with adjustable gun metal bearings.

The pump rams are of close-grained cast iron, and are cottered to the crossheads, which are fitted with slipper blocks carried by adjustable slide bars.

The suction and delivery valve boxes of the pump are interchangeable, as are also the pump barrels, without an unnecessary number of joints, and the stuffing-boxes and glands are bushed with gun metal. The pump valves, which, as will be seen, are of the double beat type, are also of gun metal, and an air vessel is also provided. The whole plant is mounted on cast iron girders forming the bed plate. We understand that this form of bed plate has been found the most suitable for conveying to the destination in mines.

It will doubtless be inquired what ratio of efficiency is to be obtained with this system of driving, and on this point the makers inform us that they have found that where an installation of pumps on this principle is operated near the bottom of a shaft, and near the driving engine, it works out much less in cost than would a similar installation driven electrically.

The reasons for this are that in the former, the losses of the dynamo and motor are omitted, and their first cost saved.

A smaller engine at the surface can moreover be used, since a well arranged wire rope transmission will give to the crankshaft of the pump as much as 90 percent of the brake horsepower of the engine.

Further than this, in the position where this pump was to work, it was calculated by the mine engineer that the first cost of the wire rope transmission would be as nearly as possible the same as the electric cable switchboard, appliances, etc. The net result, therefore, was that a smaller engine could be used, and the dynamo and motor omitted, while the cost of the transmission system was the same as compared with an electrical installation.

In the particular instance of this pump we are informed that a comparison of the two systems showed an estimated saving of nearly 50 percent in first cost, and an ultimate saving of 25 percent in the subsequent working cost of the rope-driven arrangement, as compared with an electrically-driven plant on the same duty.

Of course, if the work of pumping is required to be done at some considerable distance from the source of power, the advantage becomes much more in favour of electricity, because of the upkeep of the rope, and the losses in it. As a fact, however, the cost of upkeep of electric cables in mines is very high. Joseph Evans and Sons inform us that they have supplied a large number of these pumps for various duties, with heads varying from 600 feet to 1,700 feet, for both mines and waterworks.


The Engineer. 4th July, 1902.

Boiler Feed Pumps

For the feeding of the main range of boilers at the Wolverhampton Exhibition, Joseph Evans and Sons have installed a battery of feed pumps. They are fixed in an extension of the boiler house and draw their water from a storage tank which is supplied from the Corporation mains.

Compound Horizontal Feed Pump, Wolverhampton Exhibition.

The boiler pressure is 180 lb. per square inch, and the discharge water passes through a relief valve loaded to 200 lb. per square inch pressure when not required in the boilers. There are in all three feed pumps, all of which are compound, two of them being horizontal and fitted with the makers' patented Cornish system of compound steam cylinders, and double-acting outside packed ram pump ends. The steam cylinders are 9 inches. and 16 inches. in diameter respectively, the rams being 7½ inches in diameter, and all having a stroke of 24 inches.

Each of these two pumps is said to be capable of delivering 8,000 gallons of feed water per hour against full steam pressure, and each to be capable of  providing the maximum amount of water which the boilers are likely to be called upon to evaporate. On the other hand, it is stated that they can run at as low a rate as two piston feet per minute. The valves in the pump end are of the double beat type, and are made of gun metal with flat faces. Each pump has a large air vessel and a vacuum chamber, with the object of reducing shocks both on the suction and delivery sides to a minimum. Indeed, as might be expected from pumps made by this firm, all the three are working with no noticeable noise or vibration of any kind.

The third pump is of a new type. It is a vertical compound pump, having steam cylinders 6 inches and 10 inches diameter, and two 6 inch diameter single-acting rams, all of 12 inch stroke.

This pump possesses some novel features in the valve motion and general arrangement. It is stated to be capable of delivering about 3,500 gallons of water per hour to the boilers, and is intended to deal with the ordinary day load.

The makers, who call this pump the Beam Pump, inform us that this new type of pump has been specially designed for such work as that of electricity supply stations where the load is very variable, altering, perhaps, from the maximum to almost nothing in a short space of time.

They state that some of the more recent types of pump, notably the duplex type, have not proved entirely satisfactory for this class of work, and that while the double-ram flywheel type of pump is satisfactory to a certain extent, it has the disadvantage of not being able when required to run at a sufficiently slow rate of speed.

Moreover, they urge that the length of stroke which can be given to the flywheel type of pump is limited, since, in order to get any length of stroke, the vertical height of the pump itself would be increased beyond reasonable limits.

Vertical Compound Beam Pump.

In the beam feed pump, the crank motion of the flywheel is dispensed with, but the same vertical arrangement of steam cylinders and rams is retained, the two sides being connected together by means of a steel beam vibrating on a central shaft. Each pump ram has a crosshead and slide arrangement so as to allow for the radial motion of the beam. The actual travel of the slipper block is small; for a ram of 12in. stroke it is about l inch. The high pressure cylinder is placed over one ram and the low pressure cylinder over the other.

The steam valve motion is driven by means of a small crank on the end of the beam shaft, connected up by means of a rod to a small ‘L’ shaped lever mounted on a bracket. This lever, in its travel, moves over a small auxiliary valve working in the high pressure steam chest, and so admits steam to either end, as the case may be of a piston working in a small auxiliary cylinder. This piston is coupled by a spindle to both the high and low pressure slide valves, so that, when driven over by the steam, it reverses the slide valves of both steam cylinders simultaneously. The auxiliary valve already mentioned is also a small slide valve, and is so arranged that it uncovers the ports at the extreme end of its travel only. By its use we are informed that the speed of the pump can be reduced down to a mere crawl.


The Engineer. 6th October, 1922.

Electrically Driven Treble-Ram Pump

There has been recently a considerable amount of discussion among mining engineers as to the relative merits of electrically driven reciprocating ram pumps as compared with electrically driven turbine centrifugal pumps, and although the latter have admitted advantages, chiefly in their first cost and the smaller space occupied, many engineers and mining men still hold the opinion that the treble-ram pump is more efficient in power consumption, and is more reliable in operation than the turbine centrifugal type, especially in cases in which a moderate amount of water has to be raised to a considerable height.

Horizontal, Treble-Ram, High-Head Pump.

We illustrate above a treble-ram pump constructed by Joseph Evans and Sons (Wolverhampton Limited, which was installed recently at a colliery in Scotland where the work of pumping had formerly been done by turbine centrifugal pumps. The pump has three 9 inch diameter rams, 12 inch stroke, is fitted with single reduction, double helical, machine moulded gearing, and on the countershaft there is a belt pulley, 5ft. 9in. in diameter.

Power is transmitted from a 24in. diameter pulley on a Metropolitan-Vickers direct current motor by means of a balata belt. The bed plate of the pump is formed of four cast iron longitudinal girders, braced together at the end furthest from the pump barrels by a cross girder, whilst the pump barrels themselves are provided with bracketed feet, which span the girders, and are secured by fitted bolts, thus thoroughly bracing the bed plate girders together at that end. The slides on which the crossheads work also span the girders in the same manner, and thus form additional bracing. The side plates being separate from the bed, can be adjusted vertically to compensate for any wear that may take place.

The three working barrels are interchangeable, while all the six valve boxes are also separate and interchangeable with one another, so that in case of mishap or breakage only a comparatively small portion of the pump need be renewed. The crank shaft has four bearings provided with heavy gun metal adjustable steps, giving ample wearing surface, and the pedestals, being separate from the bed plate are independently adjustable so as to ensure proper alignment and facilitate the compensation for any wear that may take place. The connecting rods are of cast steel with adjustable brasses at each end. The crossheads are constructed separate from the rams, and have large slipper area to take the thrust from the connecting rods.

The valves are of the maker's high duty type, having gun metal mitred plates, which are so arranged as to take the main load when the valves close on their seats, but water-tightness on the mitring is not attempted; the slight annular space between the valve plate and the seating is sealed by means of a rubber disc on the back of this valve plate, and superposed thereon is another plate which takes the pressure of the spring. The valve plate works on a renewable stalk, and it will be noticed that the sleeve of this member of the valve is "blind-ended," so that there can be no passage of water in case of wear. From many careful measurements of the discharge water under heavy work, it has been found by the makers that the volumetric efficiency of pumps fitted with these valves is frequently 98 or 99 percent.

In the case of pumps of this construction dealing with water containing grit and foreign material, these valves are found to have considerable advantage. The mitre faces of the metallic portion do not allow grit or similar material to remain on the sloping faces, but if by any chance such material should lodge there, the rubber sealing disc will close over and make the valve water tight in most instances. This type of valve has been used by Messrs. Evans in pumps working against heads up to 1600ft. with quite satisfactory results.

The pump described above was tested under actual working conditions and without any attempt specially to tune it up, and the following results have been furnished by the makers:

Static delivery head against pump, 632.5ft.; friction due to about 750ft. run of 7in. delivery pipe, 6ft.; vertical height of suction, 15ft.; friction through 150ft. run of 7in. suction pipe, two retaining valves and certain bends, 4.5ft. Total head pumped against from all causes, 658ft.; speed of pump crank shaft, 41 revolutions per minute; power consumption, 128 amperes at 485 volts, giving at an efficiency for the motor of 90 per cent., 74.88 horsepower at the motor pulley; weir measurement, 330.6 gallons per minute; calculated theoretical pump displacement, 338.7 gallons per minute; volumetric efficiency of pump, 97.6 percent; horsepower in water raised against the total head from all causes, 65.9; showing a mechanical efficiency for the pump of 88 per cent.

At the same time, a test was carried out on a nominal 300 gallon per minute turbine centrifugal pump, working in the same house and under precisely the same conditions. The turbine pump was found to deliver 260 gallons per minute only, and the current used was 230 amperes at 500 volts, giving a mechanical efficiency therefore of only about 40 percent. The turbine pump has been in use some years, but has had new impellers and other renewals from time to time. The Evans treble-ram pump was ideally designed for a head from 800ft. to 900ft., and would have shown an even higher efficiency on this latter head or if designed for the actual head at which it is now working. The motor driving the Evans pump is also at a disadvantage, seeing that it is of 150 horsepower, whereas it is only called upon to give under 75 horsepower in actual running.


The Engineer. 18th March, 1960.

Multi Cylinder High Speed Hydraulic Pump

A design of high speed hydraulic pump or unit construction and with from three to six cylinders has been produced by Joseph Evans and Sons (Wolverhampton) Limited, for applications where a high-pressure pump of very small capacity is required. A typical example of one of these pumps is shown in our illustration. Each cylinder has an output of 0·6 imperial gallons per minute, and a six cylinder unit would thus have an output of 3·6 imperial gallons per minute. Delivery pressure is 1,000 lb per square inch. The eccentric shaft of the pump, which is mounted on roller bearings, is coupled directly through a flexible coupling to the motor, which runs at a synchronous speed of 1,000 rpm.

The pumps are suitable for operation with water, water/soluble oil mixture, or hydraulic oil as the working medium and the design can be adapted for use with other liquids. The units can be provided with spring-loaded relief valves, or alternatively with automatic unloading valves, which enables them to run light when operating against closed stop valves.

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