| 摘要 |
<p>The vessel containing a fire fighting liquid or solid substance, is fitted with a two stage control valve (1). This has a sliding piston (2) at the inlet end, which has a short travel, and a second piston (3) which has a much longer travel. The rod (9) attached to the second piston has a spherical tip (10) which operates the discharge valve. When the first piston reaches the end of its travel, it pushes the second piston forwards. This allows a slow escape of gas, which is relatively safe. Gas then enters through a side inlet (12), passing through a channel (13) behind the second piston, and the discharge valve is then operated.</p> |
