Displacement Speed Calculator

Displacement Speed Formula:

\[ V = \frac{Disp \times RPM}{231} \]

Flow (V):

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1. What is the Displacement Speed Formula?

The displacement speed formula calculates flow rate for hydraulic pumps and motors. It determines the volumetric flow rate based on the pump's displacement and rotational speed.

2. How Does the Calculator Work?

The calculator uses the displacement speed formula:

\[ V = \frac{Disp \times RPM}{231} \]

Where:

\( V \) — Flow rate in gallons per minute (GPM)
\( Disp \) — Displacement in cubic inches per revolution (in³/rev)
\( RPM \) — Rotational speed in revolutions per minute

Explanation: The formula converts the volumetric displacement per revolution into flow rate by accounting for the number of revolutions per minute and converting to gallons (231 cubic inches = 1 US gallon).

3. Importance of Flow Calculation

Details: Accurate flow calculation is essential for proper hydraulic system design, pump selection, and ensuring systems operate at optimal efficiency. It helps determine the right pump size for specific applications and prevents system overload or underperformance.

4. Using the Calculator

Tips: Enter displacement in cubic inches per revolution (in³/rev) and RPM values. Both values must be positive numbers. The result will be displayed in gallons per minute (GPM).

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 231 used in the formula?
A: The number 231 represents the cubic inches in one US gallon, which is necessary to convert the result from cubic inches per minute to gallons per minute.

Q2: Can this formula be used for all types of pumps?
A: This formula works best for positive displacement pumps (gear, piston, vane pumps) where displacement is fixed. It may not be accurate for centrifugal pumps or variable displacement pumps operating outside their designed parameters.

Q3: What are typical displacement values for hydraulic pumps?
A: Displacement values vary widely by pump type and size, ranging from small pumps at 0.1-0.5 in³/rev to large industrial pumps at 10-15 in³/rev or more.

Q4: How does temperature affect the calculation?
A: Temperature affects fluid viscosity and pump efficiency but doesn't change the theoretical flow calculation. Actual flow may vary due to these factors in real-world applications.

Q5: Can I use this calculator for hydraulic motors?
A: Yes, the same formula applies to hydraulic motors, where V represents the flow required to achieve a certain rotational speed at a given displacement.