Twin pumps with changeover flap valves - have devices restricting amount for which valves can open

摘要

The twin pumps are particularly for use in a central heating system, having changeover and non-return flap valves on the pressure side. These valves (13) work in conjunction with devices (16) restricting the degree for which they can open. The latter can be stops on the hinge pin for the valves, and so arranged that they can be actuated from outside the pump housing, typically by levers fixed to the hinge pin. The levers can work against scales on the outside of the housing. Alternatively, eccentric or taper pins, extending through the housing and actuated from outside, can be used to restrict valve movement.