What Causes Stator Rubber Aging in Single Screw Pumps?

 What Causes Stator Rubber Aging in Single Screw Pumps?

single screw pump, progressive cavity pump stator, stator rubber aging, screw pump maintenance, Shanghai Shangcheng Pump Valve

Description:

Rubber stators in single screw pumps may age or fail over time. This article explains the real causes of stator rubber aging, including dry running, chemical corrosion, high temperature, and abrasive wear.

What Causes Stator Rubber Aging in Single Screw Pumps?

Single screw pumps, also known as progressive cavity pumps, are widely used in industries such as wastewater treatment, food processing, and chemical transfer. These pumps are particularly suitable for handling high-viscosity fluids and media containing solids.

One of the key components of this pump is the rubber stator, which works together with the rotating rotor to form sealed cavities that move fluid through the pump. However, during long-term operation, the stator rubber may gradually age, harden, or crack.

In many cases, stator failure is not caused by natural wear alone but by several operational factors.

1. Chemical Incompatibility with the Pumped Medium

The stator is usually made from materials such as NBR, EPDM, or fluororubber. If the pumped fluid contains solvents, oils, or corrosive chemicals, these substances may react with the rubber material.

Possible effects include:

Rubber swelling

Hardening or softening

Loss of elasticity

Over time, these chemical reactions can significantly accelerate stator aging.

2. Dry Running and Excessive Friction

Single screw pumps rely on the pumped fluid for lubrication and cooling. If the pump runs without sufficient liquid, the rotor and stator will rub directly against each other.

This friction generates heat rapidly, which can lead to:

Rubber burning or deformation

Surface cracking

Permanent stator damage

Dry running is one of the most common reasons for stator failure in progressive cavity pumps.

3. High Operating Temperature

Rubber materials have specific temperature limits. If the pumped fluid temperature exceeds the recommended range for a long period, the rubber structure may degrade.

Typical signs of temperature-related aging include:

Hardening of the stator surface

Reduced elasticity

Increased internal leakage

Selecting the correct stator material is especially important in high-temperature applications.

4. Abrasive Wear from Solid Particles

Many single screw pumps are used to handle sludge, slurry, or fluids containing sand and solid particles. These particles can continuously wear the inner surface of the stator.

When abrasive wear combines with rubber aging, the stator may lose its sealing capability much faster.

5. Excessive Pressure or Speed

Operating the pump at high pressure or excessive rotational speed increases mechanical stress on the stator. Over time, this can cause fatigue and structural damage to the rubber lining.

Proper pump sizing and correct operating conditions are therefore essential for extending stator life.

Conclusion

Rubber stator aging in single screw pumps is usually the result of several combined factors, including chemical incompatibility, dry running, high temperature, abrasive wear, and excessive operating stress.

Careful pump selection, proper material choice, and correct operating procedures can significantly improve stator service life.

Shanghai Shangcheng Pump Valve Manufacturing Co., Ltd. provides reliable single screw pump solutions designed for different industrial applications and complex working conditions.

Learn more about single screw pump products here:

https://www.scpv.cn/luoganbeng/