Below are some definitions and conversion factors for the three valve flow coefficients Kv, Cv and Qn.
What is the Kv Value?
Kv value is the metric measure for the flow of a valve. It is defined as:
The volume flow in cubic metres per hour of water at a temperature of
between 5° and 40° celsius with a pressure drop across the valve
of 1 bar.
What is the Cv Value?
Cv is the imperial measure for the flow of a valve. It is defined as:
The volume flow in US gallons per minute of water at a temperature of
60° fahrenheit with a pressure drop across the valve of 1 psi.
What is the Qn Value?
Qn value is used in pneumatics to define the flow of a valve. It is defined as:
The volume flow in litres per minute of air at a temperature of 20° celsius,
with an input pressure of 6 bar and a pressure drop across the valve of 1 bar.
Converting between Kv, Cv & Qn
Kv = 0.86 x Cv
Kv = Qn / 1078
Cv = Kv / 0.86
Cv = Qn x 0.0008
Qn = Kv x 1078
Qn = Cv / 0.0008
Security & Payment Options
We accept online payments using Paypal or payments on account.
Alternatively you can use our offline payment system and we will contact you to either arrange payment or to open an account for you.
Credit card details are entered on a secure page (https secure padlock). They are fully encrypted using the most sophisticated e-payment software and also incorporate Verified by Visa & MasterCard SecureCode to ensure that your payment is secure.
We aim to deliver your order as quickly as possible subject to stock availability and payment authorisation.
Orders are processed immediately and despatched at 5pm (3pm for Post) on the same working day. Orders placed after the despatch time or on non-working days are processed and despatched on the next working day.