Inputs

Medium 
 
Flow Rate 
Inlet Pressure 
Outlet Pressure 
Inlet Temperature 
Max. Inlet Pipe Velocity 
Max. Outlet Pipe Velocity 

 Outputs

Flow Coefficient 
 
Min. Inlet Pipe Diameter 
 
Min. Outlet Pipe Diameter 
 
Flow Regime 
 
 
 

 Regulator Sizes

  DN (mm)  50   80   100   150   200   300 
  NPS (") 2 3 4 6 8 12

IP Series
Regulator

IP_image

% Open
(of realisable
range)
        - -
          - -
          - -
Size DN (mm)  50   80   100   150   200   300 
  NPS (")  2 3 4 6 8 12
IM Series
Regulator

IM_image
% Open
(of realisable
range)
        - -
          - -
          - -
Size DN (mm)  50   80   100   150   200   300 
  NPS (") 2 3 4 6 8 12

IHF Series
Regulator

IHF_image

% Open
(of realisable
range)
- -        
  - -        
  - -        

Please consult our team at info@oxford-flow.com for further guidance and information.
 

How to Use the Sizing Calculator

This sizing calculator determines the flow coefficient (Kv or Cv) required to deliver a known flow rate at a known inlet pressure, outlet pressure and inlet temperature. It can be used for both gases and liquids.

If the pressure regulator is required to operate across a range of inlet pressures, flow rates and inlet temperatures, size the PRV using:

the maximum flow rate requirement
the minimum inlet pressure
the maximum inlet temperature
the maximum outlet pressure

For gases, the sizing calculator will display if the flow is choked or unchoked. For liquids, the sizing calculator will display if the flow is cavitating or non-cavitating.

The calculator also displays the minimum inlet and outlet pipe diameter required to satisfy a maximum allowable pipe velocity, which can be set in the input table. A value of 30 m/s is considered as standard. The calculation of minimum pipe diameters does not affect the flow coefficient calculation, and assumes that the outlet temperature is equal to the inlet temperature.

The Oxford Flow pressure regulating valves are shown in the 'Regulator Sizes' table. The 'Fully Open Kv (or Cv​)​​​​​​' is the flow coefficient of the regulator when it is fully open, i.e. it has hit the hard end stop. The 'Max. Realisable K(or Cv​)' is the maximum achievable flow coefficient of the regulator when using an Oxford Flow pilot operated control system. For the IP and IM series, the Max. Realisable Kv is less than the Fully Open Kv at very low pressure differentials. The Max. Realisable Kv equals the Fully Open Kv at higher pressure differentials. For the IHF series, the Max. Realisable Kv always equals the Fully Open Kv.

The percentage that each Oxford Flow regulator is open at the user-specified flow condition is displayed in the Regulator Sizes table. A value of 100% means the regulator is open as far as is possible with the Oxford Flow control system; 0% means that the regulator is fully closed; and greater than 100% means that the regulator cannot deliver the required flow condition. Ideally, select a regulator that is 75-95% open at the maximum flow coefficient condition (the maximum flow coefficient condition as determined using the maximum flow rate, minimum inlet pressure, maximum inlet temperature, and maximum outlet pressure, see previously).

The sizing calculator uses BS EN 60534-2-1 (2011) and a minimum choked pressure ratio (no pressure recovery) from the compressible isentropic flow equations for gases (www.grc.nasa.gov).

Oxford Flow Sizing Calculator v2.1. Copyright © Oxford Flow 2018

Talk to our experts

If you would like to learn more about the solutions Oxford Flow can offer your business, please get in touch. Speak to our pressure and flow control experts to discover elegantly engineered solutions for high-pressure gas and fluid control applications that will increase reliability and reduce costs.