These function valves allow air pressure to gradually increase when a compressed air line is restarted after it has been vented for any reason (i.e. at the end of work, after an emergency stop or when adjusting the system). This gradual pressure increase, or slow start prevents shocks to the system which can occur when full working pressure is immediately introduced, thus saving wear and preventing injury to users or components. Each cylinder thus protected gradually returns to the position it stopped when the system was vented.
Working pressure: 40 to 150 PSI
Temperature Range: 5°F to 140°F
Sutable fluids: compressed air
Body: nickel-plated brass
Base: nickel-plated brass with thread sealant on tapered components
Pneumatic Slow Start System Isolating Valves are mounted on the FRL outlet. These versions protect the whole downstream installation.
All cylinders downstream of the slow start fitting pressurize simultaneously when the system is pressurized after an emergency stop.
They return to their end-of-stroke position one after the other depending on their resistive forces.
When the system has been vented, pressure is at zero. After the system air is restarted, the pneumatic slow start valve allows a gradual buildup of pressure into the system. System cylinders slowly return to their extended or retracted positions.
An adjustable needle valve is utilized to accomplish the gradual buildup of pressure in the system. Adjusting the needle valve sets the rate of fill. The setting is determined by the requirements of the installation.
When the pressure in the system is at 2/3 its maximum, the slow start valve fully opens. The operating pressure is maintained and a full flow rate is assumed until the system air is cut off and vented.
The system isolating slow start valve is mounted directly to the outlet port of the system isolation valve. Thus it protects the entire system from mechanical shock. The rate of pressurization will be common to all cylinders in the system. The speed at which each cylinder moves depends on the resistive forces acting against it.
Adjustment requires only basic tools:
1. Secure the piston with a 5.5mm (7/32") open end wrench.
2. Adjust the needle (valve opening time) using a hex key while holding the piston with the open end wrench.
3. A 1.5mm hex key is required for the 1/4" size and a 2.5mm hex key is required for the 3/8" size. Wrench flats are 5.5mm on both sizes of valves. Maximum torque for hex key: 8 in. lb.