PUMP 



6400 



PUMP 



ignition apparatus are controlled 

 by movements of the water in the 

 combustion chamber. Each of the 

 four larger pumps develops about 

 250 horse-power, and the single 

 smaller pump about 125. 



In the Pulsometer pump, Fig. 12, 

 water is forced up by the direct 

 pressure of steam. The pump has 

 two bottle-shaped chambers A and 

 B, meeting at the top, where steam 

 enters through the steam pipe into 

 the one or the other, according to the 

 position taken by a metal ball nicely 

 balanced on the partition. Each 

 chamber has a suction valve V 1 , 

 V 2 , and a de- 

 livery valve 



Fig. 11. 



kind are installed at the Chingford 

 Pumping Station, to raise water 

 through a height of 30 ft. from the 

 River Lea into the Chingford 

 reservoir. Their united capacity 

 is 180 million gallons a day. The 

 Humphrey pump is a four-stroke 

 internal combustionengineof which 

 the pump barrel is the cylinder, 

 and a column of water, continually 

 added to at the suction end, and 

 subtracted from at the delivery 

 end, is the piston. 



Its working is explained by Fig. 

 11. C is the combustion chamber, 

 V the inlet chamber, with two rings 

 of many valves opening inward, 

 T a stand-p i p e. 

 which forms part E. Exhaust Valves 

 of the connexion He/mission .. 

 between the pump S- Sea vengmg 

 and the deliver? B ' ncfA " 



pipe D. Assuming 

 the pump to be 

 idle, water will 

 stand inside it at 

 the level W.L. of 

 water outside. A 

 charge of gas and 

 air is introduced 

 above the water 

 and ignited. The 

 explosion drives 

 the column of 

 water through 



L., 



Humphrey pump as installed 

 pumping station. See text 



the play pipe into T, up which 

 it rises, losing some of its bulk 

 through D. The momentum is such 

 that the level of the tail end 

 of the column falls low enough to 

 create a partial vacuum in the 

 combustion chamber, and more 

 water enters through the inlet 

 valves, while some air is sucked in 

 through the scavenging valves S. 

 Presently the column comes to 

 rest in the tower, and the water 

 surges back, drives part of the 

 products of combustion and the 

 scavenging air out through the now 

 open exhaust valves, E ; shuts the 

 valves ; and rises into the com- 

 bustion head, compressing the air, 

 etc., which has not escaped and so 

 being brought to rest. The pres- 

 sure thus set up makes the water 

 surge back, though not so vigor- 

 ously as before, and again creates a 

 partial vacuum, which is relieved 

 by a fresh charge of gas entering 

 through valves A and B. The 

 momentum exhausted, the water 

 returns again, compressing the 

 charge, which is ignited electric- 

 ally at the proper moment. An ex- 

 plosion occurs and the cycle begins 

 over again. 'From this brief de- 

 scription it will be seen that water 

 is taken in during the power stroke, 

 and delivered during all strokes as 

 long as the water in T stands above 

 the delivery end of D, which is, of 

 course, on a lower level than the 

 top of T. The valves and the 



i fit 



Suction 

 Pipe 



Fig. 12. Pulso- 

 meter pump, 

 working by steam 

 pressure. See text 



more steam 

 from the suction 

 chamber C 

 through valve V 1 . 

 At the same 

 time steam enters 



Chingford 



(not shown). 

 In the dia- 

 gram, steam is 

 pressing o n 

 the water in 

 A, and forcing 

 it out. When 

 the level has 

 fallen to a 

 certain point, 

 the steam in 

 A begins to 

 escape into the 

 delivery pipe, 

 and condensa- 

 tion begins. 

 The sudden 

 suction first 

 draws the ball 

 across, and 

 closes the top 

 of A against 

 the entry of 

 then draws water 



B, and expels the water 

 from it in turn, till the 

 condensation level is 

 reached, when A begins 

 to discharge again, and 

 B to fill. 



In the air-lift, Fig. 13, 

 compressed air is forced 

 into a plain delivery pipe 

 at a point well below the 



water surface. The air escapes as 

 large bubbles, which form a con- 

 stant succession of elastic pistons 

 and push plugs of water upwards 

 in front of them ; the total volume 

 of water in the delivery pipe above 

 the air entry being at any moment 

 less than would be required to fill 

 it to water level, W L. The effi- 

 ciency of the air-lift decreases as 

 the distance 

 A B increases 

 proportionate- 

 ly to distance 

 B C, since a 

 larger quantity 

 of air is needed to 

 aerate a given vol- 

 ume of water. 



The hydraulic 

 ram is a device for 

 employing the mo- 

 mentum of a volume 

 of moving water to 

 deliver part of the 

 water to a higher 

 level than that of its 

 original head. Fig. 

 14 illustrates the 

 principle. Water 

 falls through pipe 

 A to a ram cham- 

 ber, wherein is a 

 valve V 1 . A delivery 

 valve V' 2 is kept 

 closed while V 1 is open, by the 

 greater pressure of the water in the 

 delivery pipe. When the velocity 

 of water escaping through the open- 

 ings reaches a certain figure, 

 V is suddenly forced up against its 

 seating, and the trapped water 

 opens V", and invades the delivery 

 pipe until its momentum is de- 

 stroyed. Then V 2 closes, and V 1 

 opens again. The proportion of 

 water delivered decreases with in- 

 crease of lift. 



The quantity D delivered will be 

 equal to half the quantity F that 

 enters the ram chamber multiplied 



by y^ m f ee t where WZ=the 



working fall and YX=the total 

 lift from the ram. Thus, if the 

 working fall be 10 ft., the delivery 

 head 100 ft., and F 200 gallons per 



minute: D = ~ X ~ } gallons per 



minute. According to 

 T the Engineers' Year 

 Book a ram actually at 

 work, with a fall of 

 t; only 10 ft., raises water 

 i2 340 ft. through three 

 ^ miles of piping. 



Ram Chamber 



Fig. 14. Pump working on hydraulic ram 

 principle. See text 



