| Description | Savery type engine for raising the water on to a double bucket reversing water wheel.
Perspective sketch of boiler and engine, n.s. Ink wash
Legend under the drawing;
A The boiler 6 feet diamerer in the middle, 9 feet deep
B Cylinder, 18 inches bore, 6 feet long
C Regulator
D Cistern of cold water
E Pipe to supply the boiler (as there is a constant evaporation of steam) with cold water from the cistern D
F Warning pipe, its use being to gage the water in the boiler
G Steam clack
H A plug to let all the water out of the boiler occasionally
I Stema pipe
K Chimney
LLL Roller handle and wheel etc to raise and let kown a damper to stop the flues and deaden the fire under the boiler
M Manhole to enter into the boiler
N Injection pipe
O Injection cock
P Snifting clack
Q Two bucketts or clacks. The flanch Q R is always under water at the extremity of which at R is a door which (with the assistance of the wqter) shuts the same air tight
S Trough alsways full of water
T Fire place under boiler
UU Two cisterns at the bottom of which at WW are tow valves fixed to the iron chains and rods X X X X
Y Cast iron pipe
Z The great axis on which is immovably fixed the overshot wheel a a 12 feet diameter, with two setts of floats, one of them inverted
at b b are two circular iron plates fixed on opposite sides of the axis Z raised with wood about a foot above the same which alternately rise the iron rods c c by which means the regulator and injection cock are opened and shut.
d d d d An iron rod fixed at one end to the roller m t g and at the other end to a plate of iron 1 which presses on the roller m by which means the whole motion of the wheel and axis are stopped tho' the water should still run into the floats of the wheel
One of the clacks W being opened, the water flowing through i into the floats of that side of the wheel will bring up the loaded buckett f and let down the unloaded one, which stopped and the other clack being opened, the water flowing through h and into the floats on the other side of the wheel will make the wheel and axis turn backwards and of course let down the buckett f and bring up the other buckett from the bottom.
N.B. The Valves W W are opened and shut at pleasure (by the person who takes the buckett out of the pit) by means of the iron rods X X and by drawing the iron rod at n, the whole wheel and axis at any time may entirely be stopped, which is occasioned by the pressure of the iron hoop l on the roller m.
As to the motion of the fire engine, it is evident that when the iron rods c c are by means of the iron plates at b b alterntely raised, which turns the regulator and injuction cock C and O, steam and cold water rushes into the cylinder B, the steam thro' the steam pipe I and cold water thro' the injetion pipe N (the air that is not rarified forcing itself thro' the snifting clack P) and perfors a perfect vacuum. The water at o being pressed by the external air (a vacuum being at B) will rush itself into the pipe Y at p and force open the clack Q will occupy the space B in the cylinder. Now the pressure of the water in B will open the door at R and with great violence run thro' the trough S into the cistern U U. The quantity of water returned into the cistern by means of the fire engine is so much that a very small addition of fresh water will keep the wheel perpetually in motion.
It should be observed that the inside of the upper flanch of the cylinder W [query B?] at x is entirely shut except a small hole in the upper side at y; now when cold water is let in by means of the injection cock, being confined, will thro' the small hole mentioned enter the cylinder in a streight line, till it meets with the thin iron plate z (which is fastened by a screw to the inside of the cylinder) which causes it to spread and to fall like a dizzling rain all over the inside of the cylinder and condenses the steam: the air at the same time as mentioned before rushing out at the snifting clack. Nothing then remains within the cylinder but a perfect vacuum. |