COMMON VALVE TYPES
Solenoid Valves
The families that appear on first RFQs and Chinese export quotes. Shared names are not interchangeable designs.
Choosing Solenoid Valves
A solenoid valve uses an electromagnetic operator, either directly or through a pilot-assisted mechanism. Direct-acting, servo-assisted and coupled designs differ in their differential-pressure requirements. State the circuit function and operating conditions before choosing a coil voltage or port size.
What to include in the RFQ
- Specify normally closed, normally open or a multi-way circuit, with a port diagram.
- Give minimum and maximum inlet pressure and differential pressure, including start-up at zero differential.
- Request the permitted fluid, seal material, contamination limits and flow capacity.
- Identify coil voltage and frequency, duty, environmental protection and any hazardous-area requirement.
A published design example
Bürkert distinguishes ordinary servo-assisted piston valves requiring a minimum differential from coupled arrangements that can open without it; verify the individual variant.
Selection scenario
On a gravity-fed or closed circulation branch, check the smallest differential pressure before selecting a pilot-assisted design. A valve that operates correctly under a pressurized test condition may not open in the intended start-up circuit.
Common selection mismatch
A coil matching the supply voltage does not establish hydraulic compatibility. Minimum differential pressure and the exact function remain separate acceptance fields.