What causes the degumming of progressive cavity pumps Stator /screw pump stator degumming
| Core cause investigation | Detailed Cause Analysis |
| Material and Process Defects | 1. Inadequate surface treatment of metal shell 2. Improper adhesive selection or curing process 3. Poor compatibility between rubber, metal and adhesive |
| Abnormal Operating Conditions | 1. Medium corrosion or rubber swelling 2. Internal stress caused by severe temperature fluctuation 3. Pressure overload or frequent impact 4. High-temperature ablation due to dry running |
| Improper Installation and Operation | 1. Coaxiality deviation between rotor and stator 2. Solid impurities in medium abrade the bonding surface |
Detailed Explanations Core Causes for Stator Debonding of Progressive Cavity Pumps
The core causes for stator debonding of progressive cavity pumps are divided into three categories, with detailed explanations as follows
1.Screw pump stator Material and Process Defects
This category refers to the inherent quality problems of the stator itself during manufacturing, which directly lead to insufficient bonding strength between the rubber bushing and the metal shell.
1)Inadequate surface treatment of metal shell
The inner wall of the metal shell is not thoroughly cleaned to remove oil stains, rust, and other contaminants. Without processes like sandblasting to increase surface roughness, the adhesive cannot form a firm mechanical interlocking structure with the metal surface, resulting in weak initial bonding force.
2)Improper adhesive selection or curing process
Selecting an adhesive that is not compatible with the stator rubber and metal material will fail to form stable chemical bonds. In addition, insufficient or excessive curing temperature, as well as insufficient curing time, will cause the adhesive to fail to reach its designed bonding strength, leaving hidden dangers of debonding.
3)Poor compatibility between rubber, metal and adhesive
2.Abnormal Operating Conditions
This category refers to the damage to the bonding layer caused by the pump operating beyond the designed working parameters for a long time.
1)Medium corrosion or rubber swelling
When conveying corrosive media such as strong acids, strong alkalis, or organic solvents, the medium will penetrate the bonding interface, corrode the adhesive layer, and destroy its chemical structure. Meanwhile, some media will cause the rubber bushing to swell or shrink, generating deformation stress at the bonding interface and tearing the bonding layer.
2)Internal stress caused by severe temperature fluctuation
Rubber, adhesive, and metal have different coefficients of thermal expansion and contraction. Frequent and drastic changes in the temperature of the conveying medium or the operating environment will cause the three materials to expand and contract inconsistently, generating continuous internal stress at the bonding interface. This stress will gradually fatigue the bonding layer and lead to debonding.
3)Pressure overload or frequent impact
Long-term operation of the pump at a pressure exceeding the rated value will cause the stator rubber to be subjected to excessive extrusion force, and the bonding interface will bear continuous tensile stress. In addition, frequent start-stop operations of the pump will cause periodic pressure shocks to the stator, which will repeatedly impact the bonding layer and accelerate its failure.
4)High-temperature ablation due to dry running
Dry running of the pump without medium lubrication will cause intense friction between the rotor and the stator rubber. A large amount of heat generated by friction will rapidly increase the temperature of the bonding interface, causing the adhesive to decompose and carbonize, and directly leading to the debonding and even falling off of the rubber bushing.
3.Improper Installation and Operation
This category refers to the damage to the stator bonding structure caused by human factors during installation and daily operation.
1)Coaxiality deviation between rotor and stator
If the rotor and stator are not aligned concentrically during installation, the pump will produce eccentric operation during operation. This will cause uneven radial force on the stator rubber bushing, and the local bonding interface will bear excessive shear force for a long time, which will gradually damage the bonding layer and cause debonding.
2)Solid impurities in medium abrade the bonding surface
Solid particles such as sand and gravel mixed in the conveying medium will enter the gap between the rotor and stator, and continuously grind the edge of the bonding interface between the rubber bushing and the metal shell during the operation of the pump. This will wear away the adhesive at the edge, and the damage will gradually extend to the entire bonding surface, resulting in debonding.
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