Pressure gradient control for central heating pumps

摘要

The pressure gradient is for control heating pumps with a continuous water heater, regulating valve and electrically driven pump. It operates with a spring-loaded control valve and member coupled to the valve seal to actuate the pump. The valve is in a line to short circuit the pump when the pressure drop exceeds a max. using the member to control the pump rev count. The seal has a cylindrical part which fits to the valve seat to limit the opening at the seal unseats. When the valve is closed, the pump operates until the valve starts to open and then cuts out after a specified period. The member is pref. a pin acting on an induction coil and bearing against the valve seal. A bush on the valve housing has its centreline in the seal continuation and encloses the adjusting trip pin and coil.