1. What is Pump Discharge Pressure?

Pump Discharge Pressure (PDP) is the pressure at the outlet of a pump, calculated from Net Positive Suction Head (NPSH), total head, and specific gravity of the fluid. It represents the total pressure the pump must generate to move fluid through the system.

2. How Does the Calculator Work?

The calculator uses the PDP formula:

Where:

• \( PDP \) — Pump Discharge Pressure (psi)
• \( NPSH \) — Net Positive Suction Head (ft)
• \( Head \) — Total Head (ft)
• \( SG \) — Specific Gravity (unitless)
• \( 0.433 \) — Conversion factor from feet of head to psi

Explanation: The formula combines suction pressure with the pressure generated by the pump to overcome system resistance and elevation changes.

3. Importance of PDP Calculation

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

4. Using the Calculator

Tips: Enter NPSH and Head in feet, and Specific Gravity as a unitless value. All values must be non-negative and valid for accurate calculations.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between PDP and system pressure?
A: PDP is the pressure at the pump discharge, while system pressure accounts for all losses throughout the piping system including friction and elevation changes.

Q2: Why is specific gravity important in PDP calculation?
A: Specific gravity affects the fluid density, which directly impacts the pressure generated by a given head of fluid.

Q3: What is the 0.433 conversion factor?
A: This factor converts feet of water column to psi (1 foot of water = 0.433 psi at standard conditions).

Q4: How does NPSH affect pump performance?
A: Adequate NPSH prevents cavitation, which can damage pump components and reduce efficiency.

Q5: When should PDP calculations be performed?
A: During system design, pump selection, troubleshooting performance issues, and when modifying existing systems.