This is because the water entering the pump applies additional pressure at the suction.
Well pump head pressure.
Total dynamic head tdh.
Or the pressure that is required for an application if a pressure tank is not used e g.
When a pump is started up with an open valve there is initially little system head pressure acting in opposition to the pump head capacity curve.
This is because the pump must use energy to bring the water to the level of the pump.
To monitor and control your pump your pump should have a suction pressure gauge and a discharge pressure gauge installed on the pump.
Whether you re pumping water or a heavy caustic solution the head achieved will be the same.
The average pressure in a domestic water system with a pressure tank used.
Considering the thermal regime in the study area calculations indicate a pressure loss of about 4 2 bar since a well head pressure whp of about 15 8 103 kpa during the oxidizer injection and of 3 6 bar taking into account the ucg operation at slightly sub hydrostatic pressure in the target coal seam which is expected to be in an acceptable range for the chosen liner diameters and well dimensions.
If the water level is higher than the pump then the suction head is negative and pump head will increase.
In this study it was decided to apply inner liner diameters of about 8 9 cm 3 and.
Given the lower system head the intersection of the h q curve with the system head curve is out towards the right end of the h q curve at or near runout.
The discharge pressure of the pump should be approximately equivalent to the total dynamic head tdh required by the system tanks pipes elbows valves flanges and fittings.
Conversely if the pump is located above the water to be pumped then the suction head is positive and the pump head will decrease.
Where p pressure psi h head ft.