Valve Selection Guide
Valve Terms
- Breaking Pressure:
The minimum pressure required to produce flow through a valve.
- Duty Cycle:
100% duty cycle is defined as continuous operation without any damage occurring. For intermittent duty cycle (<100%), alternate energized and de-energized state at regular intervals to allow the valve to completely cool down to room temperature.
F = active concentration / total concentration
- Flow Patterns:
A diagram showing how flow can be directed using a particular valve. (See the “Flow Patterns” box below for further explanation.)
- Normally Closed:
Valve stays closed in de-energized state; opens when energized.
- Normally Open:
Valve stays open in de-energized state; closes when energized.
- Pressure Differential or Pressure Drop:
The difference between the inlet and the outlet pressure through a valve. The outlet pressure is lower than the inlet pressure due to the restriction caused by the valve.
- Three-Way Valve:
Has three ports. Depending on the particular valve, all three ports may be open, two ports may be open, or all ports may be closed.
- Two-Way Valve:
Has a single inlet port and a single outlet port.
Selecting your Valve
- Choose a valve type depending on your application. Our manual valve selection includes ball, check, diaphragm, elliptic, metering, needle, pinch, plug, pressure relief, and stopcock valves. Our actuated valve selection includes electrically actuated ball, elliptic, pinch, proportioning, and general-purpose solenoid valves.
- Consider your fluid type (liquid or gas) and its characteristics to determine compatible valve materials. Teflon
withstands many harsh or corrosive chemicals. For safety reasons, always use metal valves for pressurized gases. - Determine the temperature, pressure, and flow rate under which your valve will be operating. In general, metal valves withstand higher temperatures and pressures than plastic valves.
- For solenoid valves, consider response time and length of time valve will be energized. Continuous (100%) duty solenoid valves are best for frequent on/off cycling. Choose normally closed or normally open depending on the state the valve will be in most often.
- Consider your maintenance requirements. Ball valves resist plugging and are easiest to service.