Rotary Pump

Entry

Rotary pump of the push-and-pull principle, consisting of a cylindrical drum with two conduits, one for suction and one for expulsion, and with a crank.

The interior of the drum is not cylindrical but heart-shaped. A large cylinder in the middle touches the wall of the drum where the incoming point of the heart is. The cylinder has a lamella coming out through a slot in the cylinder wall, working as a piston. Cylinder and piston are turned with the crank around the smaller central heart-shaped core, which guides the movement of the piston in such a manner that it always closes the gap between the cylinder and the wall of the drum. When cylinder and piston are turned round, the piston divides the space between the wall of the drum and the cylinder into two chambers, which vary in size according to the position of the piston. Thus a chamber is created that becomes progressively larger, sucking in the fluid from the inlet conduit, then when the piston passes the inlet again the fluid in that part is pushed out through the outlet by the piston. The inner wall is perforated with a number of holes for the outlet and inlet; a number of these have been closed again, suggesting that this pump was altered while testing.

The French engineer Bernard Courthaide proposed a rotative engine with three rotating pistons in an oval cylinder in 1851;¹ this pump bears a great likeness to his design and is possibly by his hand.