How do you calculate gpm on a CV?
Cv by definition is the number of gallons per minute (GPM) a valve will flow with a 1 psi pressure drop across the valve. For example a valve with a Cv of 10 will flow 10 GPM with a 1 psi pressure drop. The formula used to select the valve Cv with the specified differential pressure is: Cv=GPM/((SQ RT(P)).
How do you calculate valve flow rate?
Control Valve SizingControl Valve Sizing. When sizing a control valve, the most common approach is to calculate the flow coefficient, Cv which is a measure of the capacity of the valve body and trim. C = Q/N1 * (1/0) / (P)1/0 is the relative density.Fluid Density: 965.4 kg/m3.Flow Rate (Q): 360 m3/h.C = Q/N1 * (1/0) / (P)
What is CV in piping?
The flow coefficient, or Cv, is a universal capacity index and is simply defined as “the number of US gallons of water per minute at 60F that will flow through a valve with a pressure drop of one psi. Sometimes “pressure drop” is described as pressure differential or “delta P”.
What does CV mean in HVAC?
What is a CV rating?
The Cv rating for each valve is listed in the tables found in the valve catalog. The definition of Cv is the # of gallons of water that will flow through the valve with a 1 PSI pressure differential when the valve is open. The equations below can be used to determine: Flow Rate, given the Cv and ΔP.
How can pressure and flow rate be controlled?
For every pressure, the pump will only deliver one specific flow rate. Therefore, to control the flow of a centrifugal pump, simply set the output pressure to the point on the P-V diagram that allows the pump to deliver the desired flow rate. The output pressure of the pump is set using a back pressure regulator.
What is the relation between pressure and flow rate?
Fluid velocity will change if the internal flow area changes. For example, if the pipe size is reduced, the velocity will increase and act to decrease the static pressure. If the flow area increases through an expansion or diffuser, the velocity will decrease and result in an increase in the static pressure.
Does flow increase with pressure?
Higher pressure causes increased flow rate. If the flow rate increases, it is caused by increased pressure.