18.7.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



weight and tlie pressure of tlie expanding steam upon the small pis- 

 tun (tlie pump pistons at the same time make tlieir down stroke) ; at 

 the end of tlie up stroke a pause of one or two seconds is requisite, 

 to enable the valves of the pump pistons to fall out, so that upon the 

 down stroke of the steam piston they may take their load of water 

 •without shock. During this time it is necessary to sustain the great 

 crosshead and its load of dead weight at the point to which it was 

 elevated bv the up stroke, as otherwise it would fall back until the 

 fTipanded steam under the small piston was compressed to a density 

 enual to the pressure per square inch of the load lifted, or would 

 cause a very vioh'nt shock upon the pump valves by suddenly throw- 

 ing them out against the sides of the pumps. To avoid these evils, 

 the hydraulic apparatus D F was devised. 



Hydraulic Jlpparnliis. — When the engine makes its up stroke, the 

 plunger poles F (whicli form part of the dead weight) are lifted, and 

 the water from the stand pipes and reservoirs ci' Hows through the 

 valves d", and follows up the plunger poles as fast as they are ele- 

 vated. At the end of the stroke the spherical valves instantly close, 

 and the dead weight is suspended exactly at the point at which it had 

 arrived — and, of course, if the valves are tight, could be maintained 

 there for any given period ; in consequence of all strain being thus 

 removed, there is no pressure to close the valves of the pump pistons 

 beyond their own weight ; therefore, they fall out without the slight- 

 est shock. To make the down stroke, the equilibrium steam valve 

 Q, and the hydraulic valve O are opened simtdlaiuoushj : the water 

 from beneath the plungers escapes to the stand pipes and reservoirs 

 by the pipes d"", and the steam from the small cylinder passes by the 

 pipe q, round to the upper side of the sm;ill and annular pistons, puts 

 tlie pressure on the small piston in equilibrium, and presses upon the 

 annular piston (benealh which a constant vacuum is maintained), in 

 aid of the dead weight now resting upon the inner ends of the pump 

 balances: by the united eftbrt, the pump pistons are elevated and the 

 water discharged. Before the next stroke is made, the eduction 

 valve is opened and a vacuum formed over both pistons. 



So well does the hydraulic apparatus just described, effect the ob- 

 ject for which it was designed, that the Haarlem-mer Meer Commis- 

 sioners have decided to use only eight pumps, but of 73-iu. diam., for 

 the other engines; the chief reason for the adoption of the 63-inch 

 p-umps for the Leeghwater Engine having been the fear of the shocks 

 to which such large pump pistons are ordinarily liable. 



Buikrs. — The Leeghwater Engine is furnished vvith five cylindrical 

 boilers, each 30 feet long and 6 feet diameter, with a central fire lube, 

 4 feet diameter : a return flue passes under the boilers to the front, 

 and then splits along the sides. Over the boilers is a steam chamber, 

 4 ft. G in. diameter and 42 feet in length, communicating with each 

 boiler; from thence a steam pipe, of 2 feet diameter, conducts the 

 steam to the engine. Tlie steam space in the chamber, boilers, and 

 pipe is nearly I32U cubic feet, and as the engine draws its supplies 

 from such an immense reservoir of steam, no "primage" takes place, 

 and a very uniform pressure upon the piston is obtained until the in- 

 duction valve closes. These boilers have produced steam enough to 

 work the engine to the net power of 400 horses. The Cruquius and 

 Van Lynden Engines will have boilers capable of working to 500 

 horses' power if required. 



The Drainage. — Prior to the constructiou of the engine-house, &c. 

 an earthern dam of a semi-circular form was thrown out into the 

 lake, to enclose about ij acres; after the water was pumped out 

 from within the dam, a strong piled foundation was made, and the 

 masonry commenced at the depth of 21 feet below the surface of the 

 lake : a small steam engine was erected to evacuate the water from 

 the dam. When the Leeghwater was completed, the Commissioners 

 determined to test its merits fully before deciding on the construction 

 of the other engines upon the same model ; and as they had the means 

 of evacuating the water within the dam to any level required, the 

 Leeghwater could be tried and worked continuously under any cir- 

 cumstances, precisely similar to those which will occur during the 

 drainage of the lake, if, instead of discharging the w'ater from the 

 pumps into the upper caual, it was allowed to lall back again to the 

 level from whence it was derived. 



The average depth of the lake is 13 feet below the general level of 

 the surface water of the canal and watercourses conducting to the sea 

 sluices; when the communications between those waters and the lake 

 are closed, the engine will at first have only the head of water caused 

 by the discharge from the pumps, and the friction of the machinery, 

 to overcome ; in this state, all the tilling plates or ballast of the great 

 cap and pistons will be taken out, and counter-balances added to tlie 

 pump balance beams " out of doors," so as to take up as much of the 

 dead weight attached to the great cap as may not be required for 

 working the engine : as the lift becomes greater, the dead weight 



"in doors" will be gradually added. In this manner, the engine was 

 worked for a considerable time, to get all the parts in good working 

 order. A sub-committee of the Commission conducted a series of 

 experiments, and satisfied themselves that the Leeghwater will per- 

 form a duly of 75 million pounds, lifted one foot high, by the con- 

 sumption of 94 lb. of good Welsh coal, whilst exerting a net effective 

 force of 350 horfies' powi'r. With a lift of 13 feet, the engine easily 

 worked the eleven pumps simultaneously; the net load of water lifted 

 being Sl-7 tons, and the discharge G'j tons, per stroke. 



When the bed of the lake is cultivated, the surface of the water In 

 the drains will be kept at IS inches below the general level of the 

 bottom; but in time of winter floods, the waters of the upper level 

 of the country will be raised above their ordinary height : in which 

 case, to keep the bed of the lake drained to the regulated height, 

 the lift and head may be increased to 17 feet. To test the power of 

 the engine under these circumstances (and without regard to the con- 

 sumption of fuel), the whole of the 11 pumps were worked simulta- 

 neously, and the extraordinary quantity of 109 tons net of water was 

 raised per stroke to the height of 10 feet ; but, in practice, it will ba 

 advisable to work a less number of pumps, and increase the number 

 of strokes per minute. 



After numerous and severe trials of the engine, the Commissioners 

 were satisfied that it is capable of performing its work under the most 

 diflScult circumstances that can arise; and immediately determined 

 on having two more engines constructed, of equal size, and on the 

 same model — the only material alteration being in the arrangement of 

 the pumps; the number being reduced to S for each engine, but of 73 

 in. diameter, placed in pairs opposite each other, and the ends of the 

 balance beams projecting over the great cap of the engine (instead of 

 under as in the Leeghwater), to which they will be connected by stout 

 vvrooght-iron straps. The boilers also will be increased in number, 

 and in power nearly 100 horses. All the feed-water will be filtered 

 before passing into the boilers. 



Advantagti of Tito Cylinders.— Mmy persons imagine that the en- 

 gines are constructed with two cylinders to obtain a greater expansion 

 of the steam than would be attainable in one cylinder ; but such is not 

 the case, as no greater economy of steam can be obtained by the use of 

 two cylinders than by one, although greater steadiness of "motion for 

 rotatory engines, and less strain upon the pitwork of a mine-pumping 

 engine, may result from the use of two cylinders. In the Haarlem 

 engines two cylinders are used, because if one cylinder only were em- 

 ployed it would sometimes be necessary to use' a dead weight of 125 

 tons to overcome the resistance of the water load and friction of the 

 engine and pumps ; such a mass of iron or other heavy material would 

 be unmanageable, and no alteration in the force of the engine could be 

 effected but by taking from or adding to the dead weight, which would 

 be a source of great difficulty and inconvenience, when the varying 

 character of the load, during the drainage of the lake, is considered ; 

 particularly as at times the water will be cliarged with so much foreign 

 matter as greatly to add to the friction of the pumps. By the system 

 adopted the maximum dead-weight elevated by the small piston will 

 seldom exceed S5 tons; the additional power required being derived 

 from the pressure of the return steam, at the down stroke, on the an- 

 nular piston ; by varying the expansion and pressure of the steam in 

 the small cylinder, the engiuemancan add to,or diminish the pressure 

 upon the ;mnular piston, so as to meet any case of vnable resistance 

 without the inconvenience and delay attending an alteration of the 

 dead weight; the load is therefore under perfect command at all 

 times. 



quantity of JVater.—The area of the Haarlem Lake is 45,230 acres, 

 the estimated contents to be pumped out about SoO million tons, but 

 should the quantity be increased by any unforeseen cause even to 1000 

 million tons, the whole amount could be evacuated by the three en- 

 gines in about 400 days. 



The bed of the lake when drained must be always kept dry by ma- 

 chinery, and observations continued during 91 years show that the 

 greatest quantity of rain which fell upon the area of the lake in that 

 period would give 36 mill ion tons as the maximum quantity of water 

 to be elevated by the engines in one month; to perform this work 

 would require a force of 10S4 horses' power to be exerted during that 

 period ; the average annual drainage is estimated at 54 million tons. 



The cost of the Leeghwater, buildings, and machinery was 36,000/.; 

 of this amount about 15,000/. are due to the buildings, and certain 

 contingencies. For the foundations 1400 piles were driven to the 

 depth of 40 feet into a bed of hard sand, and a strong platform laid 

 thereon at the depth ot 21 feet below the surface of the lake ; upon 

 this platform at the distance of 22 feet from the engine-house, a'strong 

 wall pierced with arches was constructed, and at 7 feet from'the cop- 

 ing, a stout floor of oak was laid between the wall and the eugine- 



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