A useful sizing request includes fluid properties, required flow with units and reference conditions, inlet/outlet pressure range, temperature, valve function and electrical details. Cv or port size alone cannot establish that a valve will meet the duty.
Give flow data that can be evaluated
State the required flow and units, the medium and temperature, and the upstream and downstream pressures at that flow. For gas, identify the reference conditions used in the flow figure. For oil, include the grade and viscosity information available. If the demand varies, describe minimum, normal and peak operation.
Cv is a flow-capacity reference used with the applicable sizing method and operating conditions. Do not compare a liquid flow value, a gas flow at stated reference conditions and a catalog Cv as if they were the same measurement. Ask for the proposed model to be checked against the actual duty instead of choosing a universal percentage above the pipe demand.
Keep port size, orifice and operating pressure distinct
The connection size defines an installation interface. The internal flow path and valve construction also affect performance. Two valves with the same thread need not have the same capacity or minimum differential-pressure requirement.
For fluid on/off service, compare the 2W model tables and 2WB model data and PDF. Confirm the exact row, especially where a series page summarizes multiple variants. Include low-differential startup or equalized-pressure conditions in the request.
| RFQ field | Useful form of information |
|---|---|
| Medium | Name, concentration, contaminants and viscosity where relevant |
| Flow | Value, units, reference conditions and demand range |
| Pressure | Minimum/normal/maximum inlet and outlet values |
| Temperature | Fluid, ambient and separate cleaning conditions |
| Function | On/off or direction control; normal and loss-of-power state |
| Connection | Size, standard, mounting and space limits |
| Electrical | AC/DC voltage, connector, power/interface limits and duty |
Separate pneumatic directional valves from fluid valves
A 4V200 directional valve routes filtered compressed air to a working device. Its function, flow data and coil specification should be taken from the 4V200 catalog, not copied from another brand or series. Use the 2/2, 3/2 and 5/2 guide to identify the circuit function before comparing model codes.
Verify the coil and control interface
Voltage is only one electrical field. Confirm AC/DC type, connector pinout, duty, coil consumption and any required suppression or interface arrangement for the exact option. If a PLC output will drive the coil, provide its electrical limits and ask the controls designer to check compatibility. Do not assume every low-voltage coil can be driven directly by every PLC output.
Submit one complete sizing request
Attach the operating data, circuit sketch and proposed model or old nameplate. State any required response time or cycle rate as a requirement to be confirmed, rather than borrowing a performance figure from an unrelated valve. For steam duty, use the US(2L) steam selection guide as well. Request confirmation of the selected ordering code and the supporting data before purchase.
Frequently Asked Questions
- FAQ Can I select a valve from pipe size alone?
No. Provide flow, medium, temperature and inlet/outlet pressure as well as connection size. - FAQ Should I always choose the largest Cv?
No. Ask for the model to be evaluated for the required duty and control behavior. A larger catalog value alone does not establish suitability. - FAQ Does 24 V DC guarantee direct PLC compatibility?
No. Confirm coil consumption, output limits, wiring and any required interface or suppression.
Need a quotation?
Send the page link, quantity, drawings and working conditions to Kailing for review.