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Valve Specifications
Note: Hung diaphragm constructions do not require a minimum pressure differential, however, may notyield maximum flow rates at low-pressure differentials. Minimum Operating Pressure Differential The minimum operating pressure differential is required to fully open the
valve and keep it open. For 2-way
valves with a floating diaphragm, the
valve may start to close below the minimum pressure differential. For 3
and 4-way
valves, the minimum operating pressure differential is measured between the pressure and
exhaust ports and must be maintained through the operating cycle to ensure complete transfer from one
position to the other. Maximum Operating Pressure Differential (MOPD) Maximum Ambient Temperature The maximum operating pressure differential refers to the maximum difference in pressure between the
inlet and outlet ports, against which the solenoid can safely operate the
valve. If the pressure at the outlet
is not known, it is safest to regard the supply pressure as the MOPD. Minimum Ambient Temperature The maximum ambient temperature is 140ËšF (60ËšC). This limit is based on continuous energization with the
maximum fluid temperatures as shown on each catalog page. Response Time The nominal limitation of 32ËšF (0ËšC) is advisable for any
valve that might contain moisture (water vapor).
Where freezing water is not a factor, the minimum ambient temperature of the products listed in this catalog is 14ËšF (-10ËšC). Special constructions are available with low temperature elastomers to provide
service at -40ËšF (-40ËšC) ambient temperatures. Consult ASCO for more information. Response time from fully closed to fully open or vice versa depends on
valve size, operating mode, fluids,
temperature, inlet pressure, and pressure drop. The response times for Next Generation are defined as:Small direct acting
valves – 10 to 60 msecLarge direct acting
valves – 25 to 90 msec Internally pilot operated
valves: - Small diaphragm types – 20 to 100 msec- Large diaphragm types – 80 to 150 msec
- Small piston types – 80 to 150 msec
- Large piston types – 105 to 200 msecOperation on liquids has relatively little effect on small direct acting
valves, however, response times oflarge direct acting and internally piloted
valves may be lengthened by 50% to 100%. Viscosity All
valves with a pressure rating for light oil are designed for use with oils rated for a maximum of 300
SSU's with the following exceptions:Series 8314, 8317, 8321 – 45 SSUSeries 8345 – 50 SSU
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