| 摘要 |
A fire extinguisher includes a pressure vessel containing an extinguishing agent and pressurized gas and a valve remotely operated by a manual control at the outlet end of the delivery hose for controlling the discharge of the extinguishing agent from the pressure vessel to the delivery hose. This discharge control valve is opened and closed by a pneumatic cylinder operated by pressurized gas from a valve pneumatically operated by a manually actuated valve mounted near the outlet end of the delivery hose. For purging the hose of accumulated dry chemical, a second valve is positioned in the discharge conduit between the discharge control valve and the hose and is arranged to open and close simultaneously with the main discharge valve responsive to actuation of the valve at the outlet end of the discharge hose; a second manually actuated valve is provided to permit the second valve in the discharge conduit to be opened even though the main discharge valve is closed, and there is a gas pressure line from the pressure vessel to the discharge conduit between the main discharge control valve and the second control valve therein whereby gas pressure from the vessel is introduced into the discharge conduit when the main valve therein is closed to purge the discharge hose of dry chemical therein and to fluidize dry chemical in the discharge conduit when the main valve is open. The system also includes a three-way manually actuated vent valve in the line connecting the pressure vessel to the pressure gauge whereby prior to testing pressure the pressure gauge can be exhausted and sticking eliminated, so as to assure an accurate pressure reading at any time.
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