1. What is Pumping Speed?

Pumping speed (S) is a measure of a vacuum pump's ability to remove gas from a system, defined as the volume flow rate of gas at the pump inlet under specified conditions.

2. How Does the Calculator Work?

The calculator uses the basic pumping speed equation:

Where:

• \( S \) — Pumping speed (L/s)
• \( Q \) — Gas load (mbar·L/s)
• \( P \) — Pressure (mbar)

Explanation: The equation shows that pumping speed is directly proportional to the gas load and inversely proportional to the pressure.

3. Importance of Pumping Speed Calculation

Details: Knowing the pumping speed is essential for designing vacuum systems, selecting appropriate pumps, and understanding system performance under different operating conditions.

4. Using the Calculator

Tips: Enter gas load in mbar·L/s and pressure in mbar. Both values must be positive numbers. The calculator will compute the required pumping speed in liters per second (L/s).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical pumping speed range?
A: Pumping speeds vary widely from small pumps (0.1 L/s) to large industrial pumps (10,000+ L/s), depending on application.

Q2: How does temperature affect pumping speed?
A: Pumping speed is typically specified at standard temperature (20-25°C). At different temperatures, gas density changes may affect actual performance.

Q3: What's the difference between pumping speed and throughput?
A: Throughput (Q) is the quantity of gas flowing, while pumping speed (S) is the volume flow rate at a specific pressure.

Q4: Why does pumping speed vary with pressure?
A: Most pumps have different speed characteristics in different pressure regimes (molecular flow, transition flow, viscous flow).

Q5: How do I account for conductance limitations?
A: The effective pumping speed at a chamber is reduced by the conductance of the connecting piping (1/S_effective = 1/S_pump + 1/C).