Pneumatic control system emergency valve - has selector member positions changed by impulse or manual control

摘要

The emergency valve is for a pneumatic or hydraulic control system, particularly for pneumatic doors. A housing with an inlet and two outlet unions has two two-position selector members working in bores. In the common first position of the members a free passage is formed between the inlet and the first outlet unions, and in the second position of the first member this passage is shut, a free passage being simultaneously formed between the inlet and the second outlet, also one between the first and second outlets. In the second position of the second member a throttled passage is formed between the inlet and the first member. Impulse-operated devices change the members over together from the first to the second positions, and separately in the reverse direction, and there is also a manual control changing them over together to the second positions.