Comprehensive analysis of pressure piping component type testing for general valves

General valves encompass a wide range of types including gate valves, globe valves, throttle valves, check valves, ball valves, butterfly valves, diaphragm valves, plug valves, piston valves, solenoid valves (electromagnetic drive open/close structures), sewage valves, drain valves, plug valves, and disk valves. To ensure the safety, reliability, and longevity of these components in pressure piping systems, a detailed type testing process is essential.

premium ball valves

Technical Document Review

1.Design Conditions:

Usage conditions, product standards, and technical requirements for special applications.

2.Material Selection:

Suitability of materials for the body, sealing elements, and other parts against design conditions.

3.Sealing Structure:

Compliance of the sealing structure type and sealing element selection with design conditions.

4.Strength Verification:

Strength calculations for the body (when not specified in standards), connections, and moving parts, including operational force or torque.

5.Material Forming:

Forming methods and technical requirements for body materials (e.g., casting methods and defect acceptance levels, forging methods and grades).

6.Technical Requirements for Welding, Heat Treatment, and Nondestructive Testing:

Correctness of technical requirements for processes involving welding, heat treatment, and nondestructive testing.

7.Inspection and Testing Procedures:

Accuracy of inspection and testing procedures outlined in technical documents.

Valves

Inspection and Testing

1.Appearance and Marking Inspection:

Checking the external appearance and markings of the valves.

2.Mechanical Properties and Chemical Composition:

Testing the mechanical properties of iron body materials and the chemical composition of other body materials.

3.Dimensional Verification:

Measuring minimum wall thickness of the body, minimum diameter of the stem, and thread dimensions of connections.

4.Strength and Sealing Tests:

Conducting strength and sealing tests on the valves.

5.Operational Tests at Room Temperature:

Performing open/close operations under pressure: 100 cycles for solenoid valves, 20 cycles for check valves, and 5 cycles for plug valves.

6.Tensile Testing for Steel Gate Valves:

Conducting tensile tests on the open/close components (for nominal diameter DN ≤ 200mm and nominal pressure PN ≤ 16.0MPa).

7.Hardness Testing of Welded Sealing Surfaces:

Testing the hardness of welded sealing surfaces (e.g., gate valve gates, globe valve disks, check valve disks, butterfly valve bodies or disks, and metal-seated ball valve seats and balls).

8.Anti-Static Performance Test (where applicable):

Testing the anti-static performance of valves.

9.Vibration Resistance Test (where applicable):

Testing the vibration resistance of valves.

10.Emission Testing:

Conducting emission tests for valves with bellows stem sealing structures.

11.Low-Temperature Testing (where applicable):

Performing tests in low-temperature environments.

Sampling Rules

1.Sampling for Type Testing:

Selecting 2 different specifications from similar typical structures for type testing. The sampling base should not be less than 5 units. Additional samples may be required to cover pressure, size, and temperature parameters.

2.High-Pressure and Large-Diameter Valves:

For valves with PN ≥ 10MPa and PN × DN ≥ 5000MPa·mm or DN ≥ 1000mm, the sampling base should not be less than 2 units.

Coverage Criteria

1.Structural Coverage:

Globe valves can cover throttle valves; other valve types cannot cover each other.

2.Specification and Pressure Rating Coverage:

Coverage rules based on nominal pressure (PN) and nominal size (DN):

PN ≤ 4.0MPa: PN* ≤ PN, DN* ≤ 2DN

4.0MPa < PN < 10.0MPa: PN* < 10.0MPa, DN* ≤ 2DN

10.0MPa ≤ PN ≤ 16.0MPa: PN* ≤ 16.0MPa, DN* ≤ 2DN

16.0MPa < PN ≤ 32.0MPa: PN* ≤ 32.0MPa, DN* ≤ 2DN

PN > 32.0MPa: PN* ≤ PN, DN* ≤ 2DN

Special notes apply for specific pressure ratings and sizes.

3.Applicable Temperature Range:

The temperature range should be determined based on the type-tested samples, ensuring that the design temperature is not lower than -46°C.

This comprehensive type testing process ensures that general valves used in pressure piping systems meet stringent safety and performance standards, thereby enhancing the reliability and efficiency of industrial operations.