Pre-Action valve

The Inbal Pneumatically Actuated, Double Interlocked, Preaction Valve utilizes an Inbal Dry Pipe Valve and a pneumatic pilot system. The Inbal Valve is controlled by pressure maintained in the pneumatic release system and supervisory pressure maintained in the sprinkler piping system.

The Inbal Double Interlocked Preaction Valve will open to fill the sprinkler system with water only after both of the following occurrences: Activation of the release system and relieving of supervisory pressure from the sprinkler system. As soon as the releasing system and the sprinkler piping are reset, the Inbal Double Interlocked Preaction Valve resetting is merely done by activating the reset knobs. If only the pneumatic release system operates, an alarm will activate but the Inbal Valve will not open. If the sprinkler piping is damaged or a sprinkler is broken or fused but the pneumatic release system has not activated, an alarm will activate without opening the Inbal Valve.

The dry pilot line of closed sprinklers with a fixed temperature release is located over the protected area and it is pressurized with compressed air or nitrogen. The dry pilot line is connected to one of the Pneumatic Actuators in the Inbal control trim, which is normally held closed by the pressure maintained in the release system. The other Pneumatic Actuator is held closed by the supervisory pressure in the sprinkler piping system.

The Inbal Preaction Valve is used for automatic or manual operation as a refrigerated area system or when it is essential to prevent accidental water discharge.

The Inbal Double Interlocked, Preaction Valve is available in sizes 11⁄2″ (40 mm) to 12″ (300 mm). The valves have threaded, flanged, grooved, or wafer inlet and outlet ends and can be used in vertical or horizontal installation. The standard material Inbal Preaction Valve is rated to 300 psi (21 bar).

The only moving part in the Inbal Automatic Water Control Valve, when it operates, is the reinforced sleeve which forms a drip-tight seal with the corrosion resistant core. It has a smooth opening to prevent any water hammer in the piping system.
The unique design and variety of materials and coatings make the Inbal Double Interlocked Preaction Valve dependable for a prolonged period of service regardless of water quality.