Hydraulic Pump Sizing Calculator

Hydraulic Pump Displacement Formula:

\[ Disp_{ps} = \frac{Q \times 231}{RPM_{ps}} \]

Pump Displacement (Disp_ps):

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1. What is Hydraulic Pump Displacement?

Hydraulic pump displacement refers to the volume of fluid that a pump can deliver per revolution of its input shaft. It is a critical parameter in hydraulic system design that determines the pump's flow output capacity at a given speed.

2. How Does the Calculator Work?

The calculator uses the hydraulic pump displacement formula:

\[ Disp_{ps} = \frac{Q \times 231}{RPM_{ps}} \]

Where:

\( Disp_{ps} \) — Pump displacement (cubic inches per revolution)
\( Q \) — Flow rate (gallons per minute)
\( RPM_{ps} \) — Revolutions per minute
231 — Conversion factor (cubic inches per gallon)

Explanation: This formula calculates the theoretical displacement needed from a hydraulic pump to achieve a specific flow rate at a given rotational speed.

3. Importance of Pump Sizing

Details: Proper hydraulic pump sizing is essential for system efficiency, performance, and longevity. Undersized pumps cannot deliver required flow, while oversized pumps waste energy and increase costs.

4. Using the Calculator

Tips: Enter flow rate in gallons per minute and pump speed in revolutions per minute. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is 231 used in the formula?
A: 231 is the conversion factor from gallons to cubic inches (1 gallon = 231 cubic inches), necessary for consistent units in the calculation.

Q2: What is typical pump displacement range?
A: Hydraulic pump displacements typically range from 0.1 to 20+ cubic inches per revolution, depending on pump type and application requirements.

Q3: How does pump displacement affect system pressure?
A: Pump displacement determines flow rate, while system pressure is determined by the load resistance. The two are independent but both affect hydraulic power output.

Q4: Can this formula be used for all pump types?
A: This formula provides theoretical displacement for positive displacement pumps (gear, vane, piston). Actual flow may vary due to efficiency factors and pump design.

Q5: How do I account for pump efficiency?
A: For actual flow requirements, divide the theoretical flow by the pump's volumetric efficiency (typically 85-95% for most hydraulic pumps).