Absperrklappe mit Gegengewicht

The safety butterfly valve used generally in order to protect a pump or a turbine and permits an opening and/or a closing according with the process. The counterweight actuator consists of a weight fixed to an arm, which is mounted on the shaft of the valve. The opening and the upholding in opening make by a hydraulic jack. The weight closes the valve when the pressure of the jack is out.


The hydraulic power pack and the electrical cubicle are fixed on the same frame. To operate many valves is possible with the same equipment: in this case each valve has got an independent circuit, but with a common pressure supply.

The valve is holded in opening with the hydraulic pressure, it is necessary to compensate the internal hydraulic leakages, risponsable of a falling pressure and then a, not desirable, progressive closing of the valve. Two different technologies can make this « leakage control cycle » (Automatic cycle) :

a) Technology with limit switch : When the « leakage control » switch, located few degrees before the « opening » limit switch, switches on, the hydraulic pump starts. This technology is supplied in standard.

b) Technology with accumulator. A « low pressure » pressure gauge starts the hydraulic pump in order to blow up the accumulator.

Technical data

158106 - Technical sheet - JMC Masse Motrice

Product sheet JMC Butterfly Valve with Counterweight SAPAG-VALVES-0032-ENG-2302