The hydraulic control system is installed to permit rapid actuation of the dry-type magazine sprinkler system. It uses seawater from the firemain for the operating pressure to actuate or secure the magazine sprinkler system.

The hydraulic control system (which is better known as the operating pressure circuit) consists of the control system piping, manual control valve, hydraulically operated remote control valve, spring-loaded lift check valves, and a hydraulically operated check valve (normally used with the diaphragm-operated magazine sprinkler valve) or a power-operated check valve (normally used with the piston-operated magazine sprinkler valve).

Operating Pressure Circuit (Control System Piping)

The operating pressure circuit connects the manual control valves, the hydraulically operated components of the control system, and the magazine sprinkler valve. The operating pressure circuit is divided into an open and a close loop. The open loop transmits operating pressure from the open port of the manual control valve(s) to the operating chamber of the magazine sprinkler valve and the inlet of the hydraulically operated check valve via the hydraulically operated

remote control valve. The close loop transmits operating pressure from the close part of the manual control valve(s) to the operating pressure connections of the hydraulically operated remote control valve and the hydraulically operated check valve.

Manual Control Valves

The manual control valve is a rotary disk plate-type valve that is installed to permit rapid hydraulic operation of the magazine sprinkler valve. Most systems allow manual sprinkler activation and securing from either a local operating station or a remote station. This application uses the three-way, three-position manual control valve (fig. 2-15). Applications that do not incorporate a remote manual control station or an automatic control feature use a three-way, two-position manual control valve.

A locking device, in the form of a key, is installed in the control valve handle to prevent accidental operation of the sprinkler system. The locking key is secured to the handle with a single strand lead wire seal and fastened to the valve cover by means of a safety chain,

Figure 2-15.-Manual control valve.

Hydraulically Operated Remote Control Valve

The hydraulically operated remote control valve (fig. 2-16) is a diaphragm-operated, globe-type valve that is opened by operating pressure acting against the underside of the disk and closed by operating pressure acting on the top of the diaphragm. The purpose of this valve is to permit the magazine sprinkler valve to be secured from an operating station other than the one from which it was actuated Additionally, this valve permits the magazine sprinkler valve to be secured from

Figure 2-16.-HydraulicalIy operated remote control valve

Figure 2-17.-Spring-loaded lift check valve,

any control station when it has been actuated automatically.