GPVs are used to model situations and devices where the flow-to-headloss relationship is specified by you rather than using the standard hydraulic formulas. To specify a discharge coefficient, change the Coefficient Type to Discharge Coefficient. If you donвЂ™t know the headloss coefficient, you can also use the discharge coefficient, which will be automatically converted to an equivalent headloss coefficient in the program. A TCV is a valve that has a minor loss associated with it where the minor loss can change in magnitude according to the controls that are implemented for the valve.

TCVs are used as controlled minor losses. FCVs do not limit the minimum flow rate or negative flow rate (flow from the To Pipe to the From Pipe). These valves do not automatically check flow and will actually boost the pressure in the direction of reverse flow to achieve a downstream grade that is lower than the upstream grade by a set amount.ДЇCVs are used to limit the maximum flow rate through the valve from upstream to downstream. PBVs are used to force a specified pressure (head) drop across the valve. The valve can be in one of three states: partially opened (i.e., active) to maintain its pressure setting on its upstream side when the downstream pressure is below this value fully open if the downstream pressure is above the setting closed if the pressure on the downstream side exceeds that on the upstream side (i.e., reverse flow is not allowed). If the head upstream is lower than the valve setting, the valve will open fully.ДЄ Pressure Sustaining Valve (PSV) is used to maintain a set pressure at a specific point in the pipe network.

If the downstream grade rises above the set value, the PRV will close. PRVs throttle to prevent the downstream hydraulic grade from exceeding a set value.

Watercad v8i minor loss in pipes