Filter protecting a ball valve sensitive to particles of grit - which interfere with its two supplementary control valves

摘要

The valve, which fits a WC cistern, is opened and closed by a diaphragm moving away from, and towards, a seating: the movements of this diaphragm are dependent on the pressure in the chamber behind it, which pressure is determined by two small supplementary valves, one in the rear wall of the chamber and the other in the diaphragm itself. The rear wall valve is operated by the float in the cistern. When it closes, pressure builds up in the chamber, and the diaphragm moves forward, closing first the mian valve and then the valve at its own centre. A filter is installed in the supply, upstream of the diaphragm, to protect the supplementary valves. The filter is in the shape of a thimble, with mesh panels let into the sides, and a flange at the bottom to hold it in place.