GB190306392A - Improvements in Pumps. - Google Patents

Abstract

6392. Behrisch, M. March 19. Concussion, preventing; pump valves.-Relatee to a method of preventing " knocking" in the valves and reciprocating parts of piston or plunger pumps, whether driven by steam, electricity, or other power. Fig. 1 shows a sectional view of the device and Fig. 2 a similar view of a modification. The usual sudden change of pressure that takes place, when the piston or plunger reverses its direction of motion, is prevented by allowing the delivery valve D to remain open for a short interval after the piston has reversed. The piston K opens the valve without shock by means of the spring A and rod B ; when the piston has reversed, the valve closes gradually by the action of the two springs F, A, and the back pressure on the piston due to the liquid also gradually decreases as the valve closes. In the modification, an annular piece R takes the place of the rod B, this form overcoming the necessity of having a valve-actuating rod, as B in the first form, working in a stuffing-box or a liquid-tight opening. To avoid great back-flow velocities, the valve is constructed so that the quantity of water forced out or displaced by the valve closing is equal to, or even larger than, the amount of water which can flow back into the pump chamber at the beginning of the back stroke of the piston.