OVERPRESSURE VALVE FOR HYDRAULIC MEMBERS TO BE USED AT MINING ADVANTAGEOUSLY AT COAL MINING

摘要

A valve assembly for a mine pit prop has a pressure relief valve (7, 12, and a load indicator (22, 23) contained in a single housing (1). The valve shutoff member (7) and seat (12) are both displaced, against a restoring force, by fluid pressure at the high pressure side 4 of the valve until the shutoff member (7) abuts shoulder 9 and thereby loses contact with the valve seat (12) to open the valve. The load indicator (22, 23) shows externally of the housing (1) the movement of the shutoff member (7) and seat (12). Adjustment of a screwthreaded abutment (25) axially along the housing (1) alters the response pressure of the valve and at the same time, the reading base (29) for the indicator (22). IMAGE