Quality Control & Testing Procedure Information Product Category: Strainers

Quality Control and Testing Procedures for Strainers

Strainers are essential components in fluid systems, designed to remove debris and contaminants to protect downstream equipment. The following quality control (QC) and testing procedures ensure that strainers meet performance, reliability, and safety requirements.

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1. Material Inspection

• Objective: Verify the quality and suitability of materials used in the strainer construction.
• Procedure:
  • Review material certificates (MTC) for compliance with ASTM, ASME, or equivalent standards.
  • Conduct chemical composition tests on metallic components (e.g., body, cover, screen) to ensure material properties like corrosion and temperature resistance.
  • Inspect seals and gaskets for compatibility with fluid types and temperature ranges.

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2. Dimensional Verification

• Objective: Ensure that the strainer dimensions meet design and specification tolerances.
• Procedure:
  • Measure key dimensions such as body length, flange size, and screen aperture using calipers, micrometers, and coordinate measuring machines (CMM).
  • Verify end connection types and dimensions (flanges, threads) as per ASME B16.5, DIN, or ISO standards.

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3. Visual and Surface Inspection

• Objective: Identify any visible defects or imperfections that may compromise performance.
• Procedure:
  • Inspect for cracks, dents, casting defects, or poor finishing on the body and cover.
  • Perform dye penetrant testing (DPT) or magnetic particle testing (MPT) for welds and joints to detect hidden defects.
  • Check screen or mesh for uniformity, proper alignment, and the absence of damage or tears.

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4. Mesh and Perforation Testing

• Objective: Ensure that the strainer screen or mesh meets specified filtration requirements.
• Procedure:
  • Measure the mesh size or perforation diameter using a microscope or precision gauge.
  • Verify the open area percentage against design specifications for optimal flow and filtration.
  • Conduct tensile strength testing for the mesh material to confirm durability.

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5. Pressure and Leak Testing

• Objective: Ensure the strainer can withstand operating pressures without leaks or deformation.
• Procedure:
  • Perform hydrostatic pressure testing at 1.5 times the maximum operating pressure.
  • Conduct pneumatic pressure tests with air or inert gas to detect leaks at joints, flanges, and seals.
  • Use a soap solution or bubble method to identify potential leakage points.

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6. Flow Testing

• Objective: Verify the strainer’s performance under real-world flow conditions.
• Procedure:
  • Simulate flow conditions using the intended fluid or a substitute with similar viscosity and density.
  • Measure pressure drop across the strainer to ensure it falls within acceptable limits.
  • Test for clogging by gradually introducing debris and monitoring strainer performance.

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7. Corrosion Resistance Testing

• Objective: Ensure materials and coatings resist corrosion in specified environments.
• Procedure:
  • Conduct a salt spray test (ASTM B117) for external corrosion resistance.
  • Test for chemical compatibility using the fluid specified in the design.
  • Inspect coatings or treatments (e.g., galvanization, epoxy coating) for uniformity and adhesion.

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8. Functional Testing

• Objective: Confirm that the strainer operates correctly and protects downstream systems.
• Procedure:
  • Test strainer cover or closure for proper fit and ease of access for cleaning.
  • Verify the integrity of sealing elements (e.g., gaskets, O-rings) to ensure leak-tight performance.
  • Check for proper assembly of all components, including the screen, body, and cover.

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9. Environmental and Durability Testing

• Objective: Assess the strainer’s performance under varying environmental conditions.
• Procedure:
  • Conduct thermal cycling tests to simulate expansion and contraction at temperature extremes.
  • Perform vibration testing to evaluate performance under operational stress.
  • Test for UV resistance for strainers used in outdoor installations.

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10. Final Inspection

• Objective: Ensure the strainer is defect-free and meets customer specifications.
• Procedure:
  • Conduct a visual inspection of all surfaces, welds, and connections.
  • Verify labeling and markings, including pressure rating, size, and material grade.
  • Ensure all accessories (e.g., gaskets, bolts, documentation) are included and correctly packaged.

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11. Packaging and Shipping Inspection

• Objective: Protect the strainer from damage during handling and transportation.
• Procedure:
  • Use protective packaging to prevent scratches, dents, and contamination.
  • Label the packaging with handling instructions (e.g., “Fragile,” “Keep Upright”).
  • Include user manuals, installation guides, and quality certificates in the shipment.

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Documentation and Certification

• Objective: Provide customers with assurance of quality and compliance.
• Procedure:
  • Maintain records of material test reports, inspection results, and calibration certificates.
  • Issue pressure test certificates and quality assurance documents with each unit.
  • Ensure compliance with industry standards such as ASME, API, or ISO.

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Relevant Standards

• ASME B31.3: Process piping code
• ASTM A182/A105: Standards for materials used in strainer construction
• ISO 9001: Quality management systems
• API 614: Standards for lubrication and sealing systems, including strainers
• ASTM B117: Salt spray test for corrosion resistance

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Key Considerations

• Customization: Adapt QC procedures to match specific customer or application requirements.
• Traceability: Assign unique serial numbers for each strainer to facilitate traceability.
• Calibration: Use calibrated equipment for all measurements and tests.

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