422 KIN EM A TICS OF MA CHINEE Y.
101.
Eve's Chamber-wheel Gear. Plate XXXVII. Fig. 1.
The old chamber-wheel train of an American, Eve, gives us what is really the foundation, as to form, of that of Evrard. In this machine (Fig. 1, PL XXXVII.), which was patented in England in 1825,* the pump-wheels are essentially two unequal spur-wheels having a diametral ratio 1 : 3. The cylindric axoids of the bodies a and b, whose shafts are connected beyond the chamber by a pair of common spur-wheels whose diameters are as 3 : 1, roll together at mn, while the teeth of the wheel a carry the fluid in the direction of the arrow. On the line of centres they pass the space of b with higher pair-closure, in precisely the way described in connection with Fig. 2, PL XXXV.
In France Ganahl obtained a patent in 1826 for a machine very similar to that of Eve ; he intended it both as a motor and a pump.-f- He made, however, the wheel b conical, like the plug of a cock. We can see the idea which led to this form of construc- tion, the inventor looked upon the wheel a as a piston -wheel, and b as a valve arrangement. Ganahl's machine is strictly a chamber- wheel train formed from a pair of bevel wheels.
102.
Revillion's Chamber-wheel Gear. Plate XXXVII. Fig. 2.
The general principle enunciated in 93 that a chamber- wheel train could be made from any form of the mechanism. (E z 2 ) includes also the case of screw-wheels. This has been known for a long time, and many attempts have been made to apply it
- Ewbank, Hydraulic and other Machines, 1870, p. 287, also specially Bataille
and Jullien, Machines a Vapeur, vol. i., 1847-9, p. 440, where other forms are also mentioned.
f Propagation Industrielle, vol. iii. 1868, p. 55.
