424 



SCIENTIFIC NEWS. 



[May 4, 1888. 



of ^apetrjf, Hectares, etc* 



INSTITUTION OF CIVIL ENGINEERS. 

 At the meeting on the 24th of April, the President, Mr. 

 Bruce, being in the chair, the paper read was on " The 

 Distribution of Hydraulic Power in London," by Mr. 

 Edward Bayzand Ellington, M. Inst. C.E. 



The author observed that water-power was no new 

 force, but that, as formerly understood, it was limited in 

 its application to systems of mechanism suitable for the 

 low pressures found in Nature. The effects obtained 

 by the use of high pressure were so different in degree 

 from all previous experience that a new name was 

 needed and had been found in the term " Hydraulic 

 Power." Bramah's genius produced the hydraulic-press, 

 and he clearly foresaw the future development and great 

 capabilities of his system ; but it was reserved for Lord 

 Armstrong to work out and superintend the intricate 

 details that had to be developed before the system could 

 be made fully serviceable. The public supply of 

 hydraulic power in London constituted the latest develop- 

 ment of this system. The hydraulic power was supplied 

 through mains charged by pumping at a pressure of 

 700 lbs. per square inch. The first and largest pumping- 

 station had been erected on a site known as Falcon 

 Wharf, about 200 yards east of Blackfriars Bridge. The 

 engine-house at present contained four sets of pumping- 

 engines, each set being capable of exerting 200 indicated 

 H.P. The engines were vertical-compound, of a type 

 comprising the advantages of a three-throw pump with 

 direct connection between the pump-plungers and the 

 steam-pistons. Each set of engines would deliver 240 

 gallons of water per minute into the accumulators, 

 at 750 lbs. pressure per square inch, at a piston- 

 speed of 200 feet per minute. This was the normal 

 speed of working, but when required they could be 

 worked at 250 feet per minute, the maximum delivery 

 being 300 gallons per minute. The condensing water 

 was obtained from storage-tanks over the engine-house, 

 and was returned by circulating-pumps to one or other 

 of those tanks. The water delivered into the mains 

 was maintained all the year round at temperatures of 

 between 60*^ and 85°. The boilers were of the doubled- 

 flued Lancashire type, and were made of steel. The 

 reservoir of power consisted of accumulators. The 

 accumulators at the pumping-station were two in number, 

 each having a ram 20 inches in diameter, and of 23-feet 

 stroke. The weight-cases were of wrought-iron, and 

 were filled with iron slag. The total weight of the case 

 and load on each ram was approximately 106 tons, corre- 

 sponding to a pressure of 750 lbs. per square inch. The 

 storage-tanks formed the roofs for the engine and boiler- 

 houses. The water for the power-supply was obtained 

 from the River Thames, and was pumped into the tank 

 over the engines. The water passed through the filtering- 

 apparatus by gravity into the filtered water-tank over the 

 boiler-house, which was 7 feet below the level of the 

 unfiltered-water tank. The filters consisted of cast-iron 

 cylinders, and each contained a movable perforated piston 

 and a perforated diaphragm, between which was intro- 

 duced a quantity of broken sponge ; the sponge was com- 

 pressed by means of hydraulic pressure from the mains. 

 The deUvery of power-water from the Falcon Wharf 

 pumping-station was through four 6-inch mains. The most 



distant point of the mains from the accumulators was 

 at the west end of Victoria Street, and was 5,320 yards, 

 or just over three miles. To provide for all frictional loss 

 in the pipes and valves, the accumulators had been loaded 

 to 750 lbs., the stated pressure supplied being 700 lbs. per 

 square inch. ; The total length of the mains at present laid 

 was nearly twenty-seven miles. The mains were laid in 

 circuit, and there were stop-valves at about every 400 

 yards, so that any such section of main could be isolated. 

 The method employed for detecting leakage was based 

 upon an automatic record of the number of gallons 

 delivered into the mains, and in cases of abnormal 

 increase during the night, if found to arise -during the 

 early hours of the morning, the mains were tested. The 

 power-water used was invariably registered through 

 meters on the exhaust-pipes from the machines, and 

 from the meters passed to the drains. There was a 

 sliding-scale of charges from 8s. to 2S. per 1,000 gallons 

 at 700 lbs. pressure per square inch, designed to meet, as 

 nearly as possible, the variable conditions and require- 

 ments of consumers. The more continuous the use, the 

 lower the charges. The scale was intended chiefly for 

 intermittently-acting machinery, and experience had fully 

 proved that these rates were sufficiently low to effect a 

 large saving to the consumer in almost all cases, whether 

 for a large or small plant. The author believed any idea 

 of supplying power from a central source, at rates much 

 below these, to be chimerical. The practical efficiency 

 of the hydraulic system might be fixed at from 50 to 60 

 per cent, of the power developed at the central station. 

 No other method of transmission would, to say the least, 

 show a better result ; and the general convenience and 

 simplicity of the hydraulic system was such that its use 

 would hardly be affected, even if there were no direct 

 economy in the cost of working. 



In addition to the general supply of hydraulic power, 

 in the City and adjoining districts, to the six hundred 

 and fifty machines at present worked, a new departure 

 had been taken by the application of hydraulic power to 

 an estate at Kensington-court, the name given to an area 

 of about seven acres facing Kensington-gardens. Seventy 

 houses and dwellings were to be built on this estate, of 

 which thirty had been already erected. Each house was 

 fitted with a hydraulic lift, taking the place of a back 

 staircase, and the power-supply was provided on the 

 estate expressly for working these lifts. The driven 

 machinery was as of great importance to an economical 

 and satisfactory result as the distributing-plant, but this 

 obvious fact was not always understood. General re- 

 gulations had been prepared by the author, defining the 

 conditions to be observed by manufacturers in fitting up 

 machinery for connection to the power-mains. They 

 were intended to secure safety, and an efficient registra- 

 tion of the quantity of power used ; but they left the 

 question of the economy and of the efficiency of the 

 machines to be settled between the consumers and the 

 makers. In London more lifts were working from the 

 mains, and more power was used by them, than by any 

 other description of machinery. The number of all 

 classes at present at work was over four hundred. The 

 principal types in use were fully described. In some 

 cases there had been, by adopting the public supply, a 

 saving in the cost of working of about 30 per cent., as 

 compared with the steam pumping-plant previously in 

 use. Lifts were now becoming so general, and the 

 number of persons who used them was so great, that the 

 author considered it necessary to urge the importance of 



