May 19, 1916. THE COLLIERY GUARDIAN. 945 THE SOLID PISTON HUMPHREY PUMP. The superficial appearance of the Humphrey pump which we illustrate is very different from the well-known form, where the main feature is a relatively long water column enclosed in a pipe. In our issue of March 20, 1913, the typical Humphrey pump was described fully, and detailed drawings of the large installation for the Metropolitan Water Board at Chingford were given. In pumps of that type the fuel gases were burned or “ exploded ” above the water, which was thus forced downward, round two bends in the water column, and thus upwards to the delivery. In the pumps now illustrated the continuity or rela- tionship to the water column pumps lies in what is really the basic novelty of the idea, namely, the deliberate interposition of mass between the “explosion ” and the _ POWER Pts ton BvPpEft. V* I Intake C HAMber P/STON Rop. &AKK/NI I Fig. 1.—Sectional Elevation op Combustion Cylinder. work, thus limiting the resulting velocities to within practicable limits. The mass which in the typical pump is supplied in the form of a column of the liquid itself, is, in this instance, applied in the form of reciprocating metal partis, and full advantage is taken of the modifica- tion in the design by making the expansion of the burning gases lift the masses directly upwards. In all Humphrey pumps the energy given out by the ignited charge in any cycle does the work of that cycle in raising water, and also stores energy for carrying through the remaining operations. For the pump now described the two-stroke cycle has been chosen, and the combined masses including and raised by the working piston are directly connected to ia simple bucket or plunger pump. This is single-acting, and practically the whole of the energy put into the raising of the parts moving with the piston is returned to give the initial compression of the new charge. The following description, referring to fig. 1, will give an accurate idea of the method of working. The pump consists of two parts, a two-stroke cycle combustion cylinder at the top, and a single-acting water cylinder vertically beneath the combustion chamber. ' The explosion of the charge in the combustion cylinder forces up the piston, which is connected through the piston rod, crossheads and vertical rods to the pump bucket rod. This causes the pump bucket to rise, and water enters through a suction valve, and flows into the pump through the suction pipe, that already in the pump being discharged through the delivery pipe. Meanwhile, the fuel mixture in the mixing chamber and above the piston becomes slightly compressed. A little before the piston uncovers the intake ports, the exhaust valve is opened by a simple cam gear, the cam being attached to one of the reciprocating rods which connects the cross- heads. The opening of the exhaust valve allows the larger portion of the hot exhaust products to escape. The piston, crossheads, vertical rods and bucket rise still higher, and the piston uncovers the intake ports, thus allowing the slightly compressed combustible mix- ture in the mixing chamber to pass through the intake ports and sweep out the remaining products of combus- tion in the cylinder, filling the latter with a fresh combustible charge. The piston and attached parts then come to rest. These parts, which are of considerable weight, now commence the downward stroke. The intake porta are first covered by the piston, and a little later the exhaust valve closes, the further downward movement of the piston compressing the combustible charge in the cylinder. This compression is continued until the energy absorbed in the operation equals that given out by the falling masses, whereupon the moving parts come to rest again. Meanwhile, fresh combustible mixture is drawn into the mixture chamber, past an ordinary non- return valve, which closes when the moving parts come to rest. At the water end, during the downward stroke, the suction valve is first closed, a second valve being then opened to allow water to pass through into the upper portion of the pump. All the useful work is done during the expansion of the hot gases, and while the reciprocating parts are moving upwards. During the downward stroke, excepting for the slight friction, including that caused by water passing through the pump valve, the whole of the work given out by the falling masses is available for compressing -a new charge in the cylinder; and just before the masses come to rest, ignition is effected by any ordinary method, whereupon the moving masses are again forced upwards to commence a fresh cycle. An electrical contact maker may be connected to a battery and trembler coil, or a magneto, similarly fixed, may be used. Governing arrangements are provided which reduce the supply of mixture if the piston tends to move too far upwards; and when the piston passes the intake ports the extension of the cylinder above these ports becomes isolated, and forms a very efficient elastic cushion, which prevents the masses, rising much higher. Another cushion or resilient buffer is provided on the cylinder head. This does not come into action during the normal working of the pump, but when the pump is standing at rest, the whole weight of the reciprocating parts is supported by this buffer. Starting is effected by simply raising the reciprocating parte by means of a barring lever, thus introducing a combustible charge, and then allowing the reciprocating parts to fall under the action of gravitation, so as to compress the new charge, which is then ignited. So far as the power end of the pump is concerned, this can be standardised for a number of different outputs of water raised to a greater or less height, according to requirements. For example, the 3 in. pump shown in fig. 2 is made in a series of nine combinations of the same combustion cylinder, and its accompanying parts with pump ends of various diameters giving a range of head from 170ft. down to 8 ft., with corresponding quantities of water from 575 gals, per hour up to 9,200 gals, per hour. In a larger size (6in. pump) the stan- dard list of head and quantity ranges from 500 ft. with Fig. 2.—Elevation of Engine and Pump. I 'O 1,500 gals, per hour to 12 ft. head and a delivery of 46,800 gals per hour. Larger sizes are in course of construction. In outlining the principle of working, mention was made of “ masses ” raised by the explosions, but it must be understood that the term is used relatively, and although no special effort has been made to cut down weights, the designs are said to have worked out very favourably in this respect. The pumps are exceptionally light for their output, a point which has a further bear- ing on the question of foundations. These only require to be of very simple construction, -arid the method of •support will bo clear from fig. 2; the two brackets cast on the water end taking the whole weight, and being themselves supported by joists. All that is necessary in arranging the pumps on their foundations is to see that the bottom flange, through which access to the pump valves is obtained, is itself easily accessible. The pump deals with the full range of suction lift possible to any' good bucket or plunger pump, but where water is being raised from a well, and the water stands lower than suction lift distance from the surface, advan- tage dan be taken of the fact- that the bucket rod works always in tension. The combustion end is separately supported at the surface, directly over the well, and the pump end near the rest level of the water; a simple extension of the pump rod with a corresponding reduc- tion of weight elsewhere converts the pump for deep well work. The analogy that these pumps bear to the familiar types of direct acting steam pumps is immediately apparent. It should be realised, however, that they are the first free piston engines on the internal combustion principle to be put into practical service, and therefore an advance in engineering practice of some considerable significance. The absence of any but rectilinear move- ment of parts would naturally seem to result in a long life for the pumps, and experience with them, so far, is stated to have verified this anticipation. It is also to be expected that the same absence of rotating parts and of any side thrust between piston and cylinder or of friction in bearings would lead'to a great measure of economy. This also has been borne out by tests. An interesting point is that, considered as an engine, the pumps have no dead centre in the ordinary sense of the term, and ignition can be timed to occur at any desired point of the stroke. For much the -same reason there is no special limit to be set to the amount of the compression pressure. For example, a 3 in. pump, running on petrol, has been worked entirely by self- ignition, relying solely on the heat of compression to fire the mixture. The pumps are arranged to work either with town gas, producer gas, or petrol; and in the larger sizes simple devices for using paraffin and heavier oil are being worked out. If desired, the same pump may work on any one of these fuels merely by fitting a simple carburetter for petrol, a mixing valve for gas, or a fuel sprayer for oils. Pumps of the above typo are being installed for the water supply of -a colliery village at Haverfordwest, for pumping water at the Bristol Gas Works, and for pump- ing sewage at Ashford. SMALL COALING STATIONS.* At a recent congress in America a report was sub- mitted by Mr. L. Jutton on the most economical appli- ances and the best manner of using them generally obtaining at coaling stations in the United States. There are four types of coaling stations of this class— a platform where the material is unloaded and delivered to the engines by hand shovelling; a stiff-leg derrick with the necessary coal storage and operating plat- forms; a station where cars are pushed up an inclined trestle and the coal unloaded into small pockets and delivered to the engines by gravity; and mechanical coal- ing stations where the coal is dropped by gravity into hoppers and elevated into large pockets by means of buckets or conveyors operated by mechanical power. Of these, the coal platform is only a makeshift. The stiff-leg derrick is probably the one most used at stations where a small amount of coal is handled. The consft-uction is much the same as for any stiff-leg der- rick. The boom, however, is generally rigid, being placed at a fixed angle, and far enough out to properly reach the centre of the track. It is, therefore, neces- sary to use only the main hoist and the swing of the derrick. Adjoining the derrick is a storage platform of proper size and length to store as much coal as is con- sidered necessary at the plant. At one of these stations where the average amount of coal handled per day was 12 tons, the cost of handling per ton Was 17'9 cents, (about 9d.). This station was worked by one man, assisted by the train brakeman in coaling engines. At another station, where the average -amount handled per day was 31’2 tons, the cost of handling per ton was 12’6 cents (6-3d.). Comparatively speaking, the first cost and maintenance of -a derrick station is low. The -third, the inclined trestle type of station, is cheaper to operate than the derrick type, except for small amounts. It costs more than the derrick, and the main- tenance is much more. For small amounts the derrick is better than the trestle type of chute, and for large amounts the mechanical type i-s the better. The mechanical type of station is coming into use more and more, and has many things to commend it for economy of working. At a certain coaling station where an -average of 44’5 tons of coal -is used, the cost of handling is 8-2 cents (4'ld.) per ton. One man is employed in the day time, and one at night. If neces- sary, this amount of coal could be increased by 50 per cent, without increasing the number of men employed. The mechanical plant is high in first cost, and the maintenance may be considerable after the plant gets old. Nevertheless, a good mechanical plant is cheap to operate, and has many pointe in its favour even when a small amount of coal is used. In general, the cost of handling coal at small coaling stations is heavy, as a certain amount of labour is neces- sary, no matter how small the amount of coal handled. It seems advisable where small coaling stations are necessary that some further occupation should be found for the men employed in the coaling plant. Where conditions allow, a water station can be operated advantageously in connection with the coaling station. If the two facilities are properly placed with respect to each other, and the most improved machinery is installed at both plants, one man in the' day time and one at night can work the combined plant where the coal con- sumption amounts to about one car load per day and the water consumption to about 40,000 gals, per day. * Railway Gazette. The late Mr. W. C. Shackleford, Burnt Green, Worcester- shire, managing director of the Metropolitan Carriage and Wagon Works, and formerly manager of the Lancaster Wagon Works, left property valued at £69,725.