Maintenance Guides 1 min read

One-way check valve inspection manual: inspection, repair, parts selection

Technical analysis: Check valve inspection checklist: disc wear, hinge pin condition, and seat integrity verification

Керівництво з перевірки клапану з односторонньою пропусканням: огляд, ремонт, вибір запчастин - UNITEC-D Industrial MRO
Керівництво для технічних осіб, які здійснюють технічне обслуговування клапанів з односторонньою пропусканням. Описує, як виконувати перевірку зношування диска, шарнірних болтів та інтегритету сідки.

1. Content and purpose

This manual is intended for technicians servicing check valves in industrial systems using water, gas or liquids. The purpose of this manual is to ensure that a complete inspection of the valve is performed for disc wear, condition of pivot bolts and seat integrity. This maintenance should be performed before the valve is used after a long period of inactivity, after irregular leaks or after a system failure.

2. Safety nets

Disconnect Power and Perform Lockout and Tagout (LOTO): Before removing the valve, ensure that the system is completely shut down and all potential sources of power are removed. Use blocking devices and markings to avoid unexpected power restorations.

Use of PPE: Use gloves, goggles, splash protection and hard hats if working in a noisy or wet environment.

Hazardous Materials Warning: If liquids or gases are used, work under appropriate conditions, using ventilation and respiratory protection.

3. Necessary tools and materials

Tool Specification Quantity
Key with removal 12–17 mm in diameter 1
Multimeter Range 0–500 V 1
Torque tool Range 1–100 Nm 1
Micrometer The range is 0–25 mm 1
Ruler The range is 0–300 mm 1
Oil mixture Special for fluids used in valves 1

4. Pre-service inspection

Point Verification Acceptance/rejection criteria Notes
1 No leaks Leaks should not be detected Use a hose or paper
2 No disc wear Wear should not exceed 0.2 mm Measure using a micrometer
3 Absence of wear of hinge bolts Wear should not exceed 0.15 mm Measure using a micrometer
4 No chips on the mesh Since should not be detected Use a ruler and a micrometer
5 No wear on the valve handle Wear should not exceed 0.1 mm Measure using a micrometer

5. Step by step procedure

  1. Unscrew the valve from the system

    Use a socket wrench to remove the screws that secure the valve to the system. Check that there is no liquid or gas in the system.

    Error: Insufficient unscrewing can lead to liquid or gas leakage.

  2. Removing the valve

    Remove the valve from the housing, using a multimeter, check the condition of any liquid or gas that may remain in the system.

    Error: Improper removal may damage the valve.

  3. Disc wear detection

    Measure the thickness of the disk with a micrometer. Wear should not exceed 0.2 mm. If the wear exceeds this value, the disc is considered unacceptable.

    Error: Incorrect measurement may lead to incorrect acceptance of the valve.

  4. Checking hinge bolts

    Measure the wear of the hinge bolts. Wear should not exceed 0.15 mm. If the wear exceeds this value, the hinge bolts are considered unacceptable.

    Error: Incorrect measurement can lead to incorrect acceptance of hinge bolts.

  5. Checking the integrity of the seed

    Use a micrometer to measure the pitch. Wear should not exceed 0.15 mm. If the wear exceeds this value, the seed is considered unacceptable.

    Error: Incorrect measurement may lead to incorrect acceptance of the seed.

  6. Valve cleaning and lubrication

    Use a special fluid to clean and lubricate the valve. Lubricate in accordance with the technical data sheet of the valve.

    Error: Improper lubrication can lead to rapid valve wear.

  7. Valve installation

    Install the valve into the system using the removal key. Use a torque tool to secure the valve with a torque of 15 Nm.

    Error: Insufficient tightening torque can cause the valve to unscrew.

  8. Leak check

    Use a hose or paper to check for leaks. Leaks should not be detected.

    Bug: Improper validation can cause leaks to be missed.

6. After-service inspection

Test Expected result Actual result Pass/Fail
1 No leaks Leaks should not be detected Pas
2 Disc wear ≤ 0.2 mm Wear should not exceed 0.2 mm Pas
3 Wear of hinge bolts ≤ 0.15 mm Wear should not exceed 0.15 mm Pas
4 Grit wear ≤ 0.15 mm Wear should not exceed 0.15 mm Pas

7. Technical assistance

Symptom A possible reason Restorative action
Leaks during operation Disc or disc wear Replace the disk or seed
Improper opening of the valve Wear of hinge bolts Replace hinge bolts
Valve opening delay Wear of the seat or discs Replace the seat or discs

8. Recommended maintenance schedule

The task Frequency Estimated time Skill level
Checking the valve for wear Monthly 15 minutes Average
Replacement of valve disks 1 time a year 20 minutes Average
Replacement of hinge bolts 1 time a year 25 minutes Average
Replacing the valve seat 1 time a year 30 minutes Average

9. List of spare parts

Description of the spare part Typical specification UNITEC-D category
Valve disc Material: stainless steel, thickness: 0.5–2.0 mm UNITEC-D Cat. 0340
Valve hinge bolt Material: stainless steel, diameter: 6–10 mm UNITEC-D Cat. 0341
Valve seat Material: stainless steel, thickness: 0.5–2.0 mm UNITEC-D Cat. 0342
Lubricating fluid Special for valves with one-way flow UNITEC-D Cat. 0343

For spare parts, open our catalog: https://www.unitecd.com/e-catalog/

10. Links

  • DSTU 2364-97 - General requirements for industrial equipment
  • EN 13445-2:2002 - Standards for enclosures and fittings
  • ISO 1042:1996 - Requirements for one-way valves
  • CE, UkrSEPRO - Certification of conformity
  • OEM documentation from the valve manufacturer

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