Single-stage pumps, also known as screw pumps , are indispensable equipment in the oil and gas, food processing, pharmaceutical, chemical, and refining industries. Their special design allows them to pump highly viscous liquids containing solid particles, corrosive substances, and sensitive materials, making the quality of the pumped medium crucial.
To ensure optimal performance and a long service life, final inspection alone is not sufficient. Inspections must also be carried out during the manufacturing process. These checks ensure that each part is manufactured and assembled according to drawings, standards, and quality requirements.
What is process verification?
Monitoring the manufacturing process includes a series of checks and tests performed at each stage of production using a single pump to ensure that no defects or deviations from the design and quality requirements occur.
In contrast to final inspection at the end of production, process control enables the rapid detection of errors in the same phase and prevents their spread to later phases.
The importance of individual pump process control
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Avoid rework and waste.
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Early detection of defects can reduce costs and time losses.
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Improvement of quality and reliability
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Precise control of components such as rotor, stator and mechanical seal can improve pump performance.
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Complies with international standards
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Sensitive industries (oil and gas, pharmaceuticals and food) only accept equipment that has passed strict quality control.
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Improving operational safety
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Identifying potential defects can prevent serious failures during real-world operation.
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Control of multiple production stages with a single pump
1. Raw material monitoring
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Verification of material test certificates.
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Analyze the chemical composition of minerals (spectroscopic analysis).
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Analysis of the hardness and mechanical properties of materials.
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To ensure the corrosion resistance of stainless steel and its alloys.
2. Control of mechanical parts
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Rotor: Measures diameter, length, and surface tolerances.
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Fixed part: Check the accuracy of the dimensions, the alignment, and the quality of the elastomer.
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Shafts and bearings: Check the surface for smoothness and conformity with the drawings.
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Use precision instruments such as micrometers, digital calipers, and coordinate measuring machines.
3. Heat treatment and coating inspection
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Checking the hardness of the rotor surface after heat treatment.
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Control of the thickness of the corrosion- and wear-resistant coating.
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Perform paint adhesion tests according to ASTM or DIN standards.
4. Welding and primary assembly inspection
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Use non-destructive testing (NDT) methods to check the quality of welds, such as:
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UT (Ultrasound examination)
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Radiation tests (RT)
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Penetration test (PT)
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Make sure the column and moving parts are aligned.
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Check the tightening torque of the screws according to the manufacturer’s instructions.
5. Final assembly inspection
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Check that the rotor and stator are correctly connected to avoid leaks.
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Check the condition of the bearings and mechanical seals.
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To ensure proper lubrication, it must be ensured that the shaft can rotate freely when unloaded.
6. Inspection during painting and application of the topcoat
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Use a paint thickness gauge to check the thickness of the paint.
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Checking the color uniformity and the corrosion protection coating .
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The adhesion of the paint was tested according to ISO 2409.
7. Monitoring and documentation of the technical documentation
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Enter all test results in the quality control sheet.
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Preparation of a final report for submission to the customer or the quality control department.
Tools and methods for quality control in the production process
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Precision measuring instruments : calipers , micrometers and special gauges.
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The coordinate measuring machine is used to check complex dimensions of rotors and stationary parts.
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Non-destructive testing (NDT) is used to detect cracks or porosity.
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Hardness tests are performed to check the mechanical properties.
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Perform hydrostatic pressure tests on sensitive components.
Process control problems with a pump
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Specialists are needed to interpret the test results .
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Precision testing equipment is expensive.
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Some tests take a long time.
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Demonstrates a high sensitivity in the production of complex parts such as rotors and stationary components.
Advantages of applying strict controls in the production process
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Reduction of costs for warranty and customer service.
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This increases the lifespan and efficiency of the individual pumps.
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Increase customer trust and strengthen the manufacturer’s brand.
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It can quickly identify and resolve problems during the production process.
Franklin Electric Mono HD Series
An example checklist for the manufacturing process of a pump
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MTC raw material release -
Dimensional control of mechanical parts
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Rotor surface hardness testing
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Non-destructive testing of protective devices and sensitive components
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Initial inspection of the assembly and part conformity
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Idle shaft power test
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Checking the paint thickness and adhesion
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Recording of the quality control document
The role of control in the production process in various industries
Oil and gas industry
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Make sure the pump is pressure-resistant and resistant to aggressive liquids.
Food and pharmaceutical industries
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Strict controls have been introduced to ensure the purity and quality of materials that come into contact with liquids.
Chemical and petrochemical industry
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Offers resistance to corrosive substances and concentrated chemicals.
Water supply and wastewater disposal
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Check the pump resistance when pumping sludge or wastewater containing solids.
In conclusion
Process control is one of the most important phases of pump quality assurance . This process prevents errors in the final stage through careful inspection of raw materials, machined parts, heat treatment, assembly, and coating.
Besides improving pump quality and lifespan, the correct implementation of these control procedures reduces costs, strengthens customer confidence, and ensures compliance with international standards. Process control is therefore not only a quality requirement but also a long-term investment in product reliability and performance.