THE CIVIL ENGINEER AND VRCHITECFS JOURNAL. 



[Jan. 



DESCRIPTION OF THE ENGINES. 



Tlie Leeghrvater Engine, as shown in Figs. 1, 2, ami 5 of tlie accom- 

 panying Enpriivings, Plates 1 and 2, has two st>»am cylinders A and C, 

 one within the other, united to the same bottom X, but tlie inner one 

 is not attached at the top, a clear space of li inch existing between 

 it and the cover, whicli serves for both cylinders. Thel.irge cylinder 

 A, is 144-37 inches diameter and li inch thick, and C, the small cy- 

 linder, 81-25 inches diameter and 1| inch thick ; both are tnilv bored 

 out, and the small cylinder is also turned on its outer circumference. 

 B is a steam j.icket for the large cylinder, cast in 13 segments — which 

 is again enveloped by a wooden casing I, having 4 inches of peat 

 ashes between them. 



Pisloris. — The small cylinder C is fitted with a plain piston of 5474 81 

 square inches area, and the large cylinder A is occupied bv an 

 annular piston of 10,323-3lj square inches area. The areas of the two 

 cylinders, after deducting ■172"S square inches for the thickness of 

 small cylinder, are as 1 to 2-S5. The internal and external packings 

 ofthe pistons consist of hard cast iron segments at bottom, with gasket 

 above, pressed down by glands, also in segments ; the open spaces in 

 the pistons cc are filled with cast iron plates, and the tops of tlie 

 pistons have moveable cast iron covers. 



Cap or Crosshead. — The pistons are connected to the great cap or 

 crosshead G by the main |)iston rod Y, of 12 inclies diameter, and by 

 four small rods y of 4-5 inches diameter (figs. I and 5). The great cap 

 G has a circular body i) feet G inches diameter, divided into eight 

 compartments, which can be filled with cast iron weights; from its 

 centre a guide spindle z passes through a stuffing box placed in tlie 

 centre of a great beam of timber 2 feet square, which passes across 

 the engine-house, and is secured to its walls; there are two other 

 guide rods, 6, which pass tlirough stuffing boxes in the arms of the 

 great cap G, and are secured to the upper and lower spring beams. 



Plungers. — Suspended from the arms of the great cap are two 

 9-in. plunger poles F, working in plunger cases D; attached to D are 

 two valve nozzles d", connected with stand pipes d', by two branch 

 pipes r/'"; the valve nozzles are connected with each other and an 

 hydrostatic equilibrium valve nozzle O, from the bottom of which a 

 branch piece is connected with the stand pipes d' by the pipes d"". 

 The exterior surfaces ofthe plunger cases D, are turned truly, so as to 

 allow the rini^s ee to slide up and down freely; the rings are sus- 

 pended from the great crosshead by rods v, and are furnished with cross 

 bearings, on which the jaws of the two air-pump balance beams E 

 rest: the inner ends of these b.dance beams move in a perfectly verti- 

 ciil line, and the outer ends are furnished with rollers working between 

 guides, to allow for the variation of the beams during the up or down 

 stroke. 



Air Pump, — Frotn the centre of the air-pump balances, the two 

 air-pump plunger pistons n' are suspended (fig.2); diameter of plunger 

 pistons 40 in., stroke 5 feet; the two air-pumps N are united bv a 

 branch piece with the bottom of the cmidenser M. The condenser has 

 an intermittant injection by a valve S-ni. diameter, and a constant in- 

 jection by another valve of 3-in. diameter. R is the condenser cis- 

 tern. 



Pipes and Valves. — L is the steam pipe (2 feet diameter) from the 

 boilers; in it is placed a double-beat governor valve of 16-in. diam- 

 eter. 



P, the induction valve, IG-in. diameter and nozzle. 

 Q, Equilibrium valve, 2U-in. diameter and nozzle. 

 S, Eduction valve, 2lj-in. diameter and nozzle. 



5, Equilibrium steam pipe. 

 The induction and equilibrium nozzles are each connected to a sepa- 

 rate port cast in the cylinder's bottom. The eduction nozzle is con- 

 nected by a pipe M, 3i-iii. diameter, to the branch-pipe M of the 

 condenser. The pipe M is also connected to the bottom of the cy- 

 linder, in which a purt is cast, which communicates with the space 

 under the annular piston; by this arrangement a constant vacuum is 

 maintained beneath that piston. 



The Hand Gear is connected to the weigh post K, and the plug rod 

 is worked by a lever and shaft T, the outer end of which is slotted 

 and worked by a pin on the sliding ring e. 



Pumps — The engine works eleven pumps of 63-in. diameter ; each 

 pump is furnished with a cast irun balance beam H (fig. I), which 

 radiates from the centre of the piston rod; the inner and outer arms 

 are of equal lengths from the centre gudgeon. The inner ends of the 

 balance beams are furnished with cast iron rollers, working against a 

 plate, fitted with guides for each roller, which is screwed up against 

 the under-side of the great cap; each beam is connected to the cap 

 by two slotted bridles, to ensure simultaneous upward motion during 

 the np-stroke of the engine. From the outer end of the balance 

 beam the pump pistou is suspended by wrought iron rods, 3-in. diam- 



eter and IG feet long, and an additional length of 14 feet of patent 

 chain cable attached to the pump piston. Fig. 3 shows a section of 

 one of the pumps, and fig. 4 an elevation of tue piston. A, working 

 barrel, G3-in. diameter ; B, windbore and clack piece ; C, the piston 

 or bucket; D, bottom valve and seat. 



The pum]) jiiston C is of a jieculiar construction; it is composed 

 of a wrought iron centre piece, 1 inch thick ; firmlv bolted to this 

 piece are two double elbow frames of cast iron, called " the cradles;" 

 the elbows are faced with gnn-metal plates ; the craciles serve to sup- 

 port two wrought iron semi-elliptic valves c c, which occupy the whole 

 area of the pump when they f dl out, and constitute in fict the piston. 

 These valves are edged with wood, having a piece of leather on the 

 upper side secured by a wrought iron gl.md ; the valvos are hung to 

 the centre piece at about 3 inches from their lower edges, so that 

 when they open during the down stroke, any dirt or s ind which has 

 lodged on the bottom may fall through. Attached to the centre piece 

 are two plates of cist iron, which serve as ballast to sink the piston ; 

 these ends are cast with a jaw, in which pieces of wood are secured 

 to prevent friction against the sides of the pump and to give steadi- 

 ness to the piston. These pistons require a weight of 1'4 lb. per 

 square inch of the area of the pump to sink them with the velocity 

 required upon the down stroke. The pump pistons of the Leeghwater 

 are not furnished with guides, as shown in figs. 3 and 4, and work very 

 well without them : but the pistons for the pumps of the Cruquius 

 and Van Lynden engines (now constructing fur the drainage of the 

 lake) will have guides, as shown in the drawings, in consequence of 

 the diameter of the pumps being incre.ised to 73 inches. 



Pump Valves. — The bottom valves have cast iron seats secured to 

 the windbore, the valve beats are of wood, and the valves are simply 

 plates of wrought ircm, 1 inch thick ; the valves are not hung on fixed 

 joints, but are each fixed to a bar, the ends of which are entered ia 

 cast iron slot pieces, allowing a rise of IJ inch, so that the valve can 

 rise altogether from its beat, and give a large water passage all 

 round. 



Power of Engines. — The steam and pump pistons both perform a 

 stroke of 10 feet in length: each pump by calculation should deliver 

 G'02 tons of water per stroke, or GG'22 tons for the eleven pumps; 

 but by actual admeasurement of the quiuitity delivered, it is found to 

 be 03 tons. The loss might be reduced, but probably at the expense 

 of increased friction. 



The Engine House is a massive circular tower, concentric to the 

 cylinders; on its walls are placed the eleven pump balances r.idiating 

 from its centre, shown in the accompanying sketch. The pump 



balances a, h, c, are placed at 120 degrees from each other; dd, ee, ff 

 ^g, are placed opposite each other: therefore, by this arrangement, 

 the equilibrium of the great cap of the engine, under which the inner 

 ends of all the balance's are concentrated, is not in any way disturbed. 

 If any of the puaqis require repairs, the opposite pairs can be easily 

 detached, without causing more than a trivial delay to the working of 

 the engine. 



The Action of the eni:;ine is very simple ; the steam being admitted 

 into the small cylinder, the whole of the dead weight and pump balance 

 beams attached to the great crosshe.id are elevated with it, and the 

 steam being cut oil' at such portion of the stroke as may be required, 

 the remainder is eSected by the momenlura acquired by the dead 



