Why Screw Pumps Should Never Run Dry: A Common Mistake That Damages Equipment

 Why Screw Pumps Should Never Run Dry: A Common Mistake That Damages Equipment

In many industrial applications, screw pumps are widely used for their stable flow, low pulsation, and ability to handle high-viscosity fluids. However, a common mistake in daily operation often leads to performance decline or even equipment failure:

👉 running the pump dry

Many users think running the pump for a short time without liquid is harmless.

But in reality:

👉 dry running is one of the most damaging conditions for a screw pump

1. Why Screw Pumps Depend on Liquid

A screw pump is a type of positive displacement pump. Its operation is based on:

The rotation of the screw inside the stator

Formation of sealed cavities to move fluid forward

In this process, the fluid itself plays a critical role:

👉 it acts as both the working medium and the lubricant

2. What Happens During Dry Running?

When there is no liquid inside the pump:

The screw and stator come into direct contact

Lubrication is lost

Heat cannot be effectively dissipated

This quickly leads to:

Increased friction

Rapid temperature rise

Material damage

3. The Most Common Result: Stator Damage

The stator in a screw pump is usually made of elastomer materials.

Under dry running conditions:

Heat builds up rapidly

The elastomer softens or deforms

Surface burning or wear may occur

As a result:

👉 pump performance drops significantly or the unit fails completely

4. Performance Degradation Over Time

Not all damage is immediate. In many cases, the process is gradual:

Flow rate decreases

Pressure becomes unstable

Efficiency declines

Eventually:

👉 the pump may no longer meet operational requirements

5. Why This Problem Is Often Misunderstood

One key reason is:

👉 damage from dry running is cumulative

At first:

No obvious signs

Later:

Performance starts to decline

Finally:

Failure occurs

This is often mistaken for normal wear or aging.

6. Common Causes of Dry Running

Dry running usually occurs under these conditions:

Starting the pump without priming

Air entering the suction line

Low fluid level

Blocked suction pipeline

👉 The pump appears to be running, but internally it is operating without lubrication

7. How to Prevent Dry Running

To avoid these issues:

Ensure the pump is filled with liquid before startup

Check suction line sealing

Avoid prolonged no-load operation

Install dry-run protection if possible

8. Conclusion

The reason a screw pump should not run dry can be summarized in one sentence:

👉 No fluid means no lubrication

From an engineering perspective:

Dry running

→ Increased friction

→ Heat buildup

→ Material damage

→ Performance loss or failure

Most pump failures are not sudden—they develop from small operational mistakes.

Understanding and avoiding dry running is essential for maintaining long-term reliability.

For more information on screw pump operation and maintenance, refer to:

👉 https://www.scpv.cn/news/874.html