Discharge Pressure Calculator

Discharge Pressure Formula:

\[ PD = PS + (Head \times SG \times 0.433) + Losses \]

Suction Pressure (PS):

psi

Head:

Specific Gravity (SG):

unitless

Losses:

psi

Discharge Pressure (PD):

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1. What is the Discharge Pressure Formula?

The Discharge Pressure formula calculates the total pressure at the discharge point of a pumping system. It accounts for suction pressure, head pressure based on fluid column height and specific gravity, and friction losses in the system.

2. How Does the Calculator Work?

The calculator uses the Discharge Pressure formula:

\[ PD = PS + (Head \times SG \times 0.433) + Losses \]

Where:

\( PD \) — Discharge Pressure (psi)
\( PS \) — Suction Pressure (psi)
\( Head \) — Head height (ft)
\( SG \) — Specific Gravity (unitless)
\( 0.433 \) — Pressure conversion factor (psi/ft)
\( Losses \) — Friction and system losses (psi)

Explanation: The formula calculates the total pressure required at the pump discharge by summing the suction pressure, pressure due to fluid column height, and system pressure losses.

3. Importance of Discharge Pressure Calculation

Details: Accurate discharge pressure calculation is crucial for pump selection, system design, ensuring adequate flow rates, and preventing cavitation or system failure.

4. Using the Calculator

Tips: Enter suction pressure in psi, head in feet, specific gravity (1.0 for water), and system losses in psi. All values must be valid (non-negative for head, SG, and losses).

5. Frequently Asked Questions (FAQ)

Q1: What is the 0.433 factor in the formula?
A: This is the pressure conversion factor that converts feet of head to psi (1 foot of water column = 0.433 psi).

Q2: How do I determine system losses?
A: System losses include friction losses in pipes, valves, fittings, and other components. These are typically calculated using hydraulic tables or software based on flow rate and pipe characteristics.

Q3: What is specific gravity and when does it change?
A: Specific gravity is the ratio of fluid density to water density. It changes with fluid type, temperature, and concentration. Water has SG = 1.0.

Q4: Can this formula be used for all fluids?
A: Yes, the formula works for all fluids when the correct specific gravity is used. The 0.433 factor is based on water, so SG adjusts for other fluids.

Q5: What are typical suction pressure values?
A: Suction pressure depends on the system. Positive values indicate pressurized suction, negative values indicate suction lift conditions.