Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

# Water Control Valves - Flow Factor Kv Diagram

## Sizing of water control valves - SI units

The flow factor Kv for control valves in water systems can be estimated from the diagram below:

• 1 bar = 1x105 Pa (N/m2)

### Example - a Water Valve and Kv value

The maximum pressure drop through a modulating control valve in a water flow system is designed to be 100 kPa. The flow through the valve is 5 liter/s. The required kv value for the valve can be estimated as indicated in the diagram below to approximately 20.

Note - larger valves (with larger Kv) reduces the maximum pressure modulating spans - limiting the ability to provide a stable process control. As a consequence - control valves are often one to two dimensions below the dimensions of the connecting pipes.

Example - with a water flow of 5 liter/s the pipe size would be in the range 3 - 4 inches (80 - 100 mm nominal). A control valve would be in the size kv ~ 20 - or in the range 2 - 3 inches (50 - 80 mm nominal).

## Related Topics

• ### Control Valve Sizing

Control Valve terminology, bodies, trim, flow characteristics, Cv and Kv sizing, noise, actuators, positioners and more.
• ### Fluid Mechanics

The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.

## Related Documents

• ### Ball Valves - Flow Coefficients Cv

Flow coefficients - Cv - for typical ball valves - reduced and full bore.
• ### Control Valves - Adding Flow Coefficients for Valves in Series or Parallel

How to add flow coefficients for control valves in series or parallel.
• ### Flow Coefficient Cv vs. Flow Factor Kv

Comparing flow coefficients Cv to flow factors Kv.
• ### Liquid, Steam and Gas - Flow Coefficients Cv

Calculate flow coefficients for the design of control valves - Imperial units.
• ### Liquid, Steam and Gas - Flow Factor Kv

Calculate flow factor Kv for liquids, steam and gases - metric units.
• ### Straight Through Diaphragm Valves - Flow Coefficients

Flow coefficients - Cv - and flow factors - Kv - for straight through diaphragm valves.
• ### Valve Authority

The valve authority expresses the ratio between pressure drop across the control valve compared to total pressure drop across the whole system.
• ### Valves Types - Operating Size Ranges

Types of valves and their typical operating sizes.
• ### Water Control Valves - Flow Coefficient Cv Diagram

Sizing of water control valves - Imperial units.
• ### Water Control Valves - Kv Calculation

Designing water process control valves and their Kv values.

## Search

Search is the most efficient way to navigate the Engineering ToolBox.

## Engineering ToolBox - SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

About the Engineering ToolBox!

We don't collect information from our users. More about

We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy here.

You can change your privacy settings by clicking the following button: .

## Citation

• The Engineering ToolBox (2008). Water Control Valves - Flow Factor Kv Diagram. [online] Available at: https://www.engineeringtoolbox.com/water-valve-kv-diagram-d_325.html [Accessed Day Month Year].

Modify the access date according your visit.

7.25.9

.