Hanbay | Valve Theory


Contact Us | Tel.: 1 800 315 4461

Contact Us | Tel.: 1 800 315 4461







Finding the
Perfect valve

In order to choose the right valve, it’s a question of identifying the type of application that’s needed. For example, needle valves are typically specified for regulating and control applications. Ball valves are used for open / close applications.


Basic valve models
(**each model has multiple variations):

Needle Valve - Gate Valve - Ball Valve - Butterfly Valve
Plug Valve - Disc Valve - Diaphragm Valve


Making the Right Choice

Choosing the right valve requires determining the CV value, max flow, fluid pressure, temperature, media, corrosion resistance and line size. Other factors such as valve availability and cost are just as important. Once you have found your valve from catalogs or other resources, you need to check if it’s available at your budgeted time and cost. Below are the 4 steps to finding the perfect valve.


1. Application - Choose valve type

Gas Media

2. Collect information to calculate CV value:

SG = Specific gravity of gas
p1 = Gas Inlet Pressure
p2 = Gas Outlet Pressure
T = Absolute Temperature
Q = Gas Flow Rate in SCFH

3. Determine CV for Gases

Liquid Media

2. Collect information to calculate CV value:

Q = Flow rate in GPM (US gallons)
G = Specific gravity of liquid
Dp = Pressure drop = inlet - outlet pressure(psi)


3. Determine CV for Liquids

4. Find out if the CV is sized right for your application, consult valve manufacturer’s catalog.



Swagelok’s Integral Bonnet Needle Valve 18 Series Example

For the SS-18RM8 valve, the CV in the catalog text table is given as CV = 1.8.

This is the max CV on an open valve. If you want to find out your CV related to the number of turns open, you have to use the graph. the CV is approx. = 0.75 when the valve is open at 2 turns.


About Us

Established in 1986, Hanbay is a manufacturer of miniature electric valve actuators that can be customized for any application, in any industry.

Hanbay’s electric valve actuators provide precise positioning, with the highest torque, resulting in accurate flow control. Our expertise is in manufacturing compact actuators capable of micro-positioning on miniature valves.

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