Advantages of Center-line Lug Wafer Butterfly Valve

The wafer-type butterfly valve with centerline lugs, as a widely used fluid control device, its manufacturing quality directly affects the valve's performance, service life, as well as the safety and reliability of the system. Therefore, strict quality inspection and control during the manufacturing process are crucial.

I. Quality Control of Raw Materials

Raw materials are the foundation for manufacturing wafer-type butterfly valves with centerline lugs, and their quality directly impacts the performance of the final product. The main raw materials for manufacturing such valves include valve body materials (e.g., ductile iron, stainless steel, etc.), valve seat materials (e.g., rubber, polytetrafluoroethylene, etc.), and valve stem materials (e.g., stainless steel, etc.).

• Valve body materials: Ductile iron is one of the commonly used valve body materials, featuring good strength and toughness. During procurement, strict inspection of its chemical composition and mechanical properties should be conducted to ensure compliance with relevant standards. For example, the tensile strength, elongation, and other indicators of ductile iron should meet the specified values to guarantee the strength and reliability of the valve body under working pressure.

• Valve seat materials: The sealing performance of the valve seat is one of the key characteristics of the wafer-type butterfly valve with centerline lugs. Rubber valve seats should have good elasticity, wear resistance, and corrosion resistance. Meanwhile, indicators such as hardness and compression set rate need to be controlled to ensure the stability and durability of the sealing performance.

• Valve stem materials: Valve stems are usually made of stainless steel, and their chemical composition and mechanical properties should meet standard requirements to ensure the strength and corrosion resistance of the valve stem, preventing valve failure due to stem corrosion or insufficient strength.

II. Quality Control During the Manufacturing Process

• Control of casting process: The casting quality of the valve body directly affects the overall performance of the valve. During the casting process, strict control of casting process parameters such as pouring temperature, pouring speed, and cooling rate should be implemented to avoid casting defects like shrinkage cavities, shrinkage porosity, and sand inclusion. At the same time, non-destructive testing such as ultrasonic testing and X-ray testing should be performed on the castings to promptly detect and handle internal defects.

• Control of machining accuracy: The machining accuracy of the components of the wafer-type butterfly valve with centerline lugs is crucial for its sealing performance and operational performance. For example, the machining accuracy of the valve body's sealing surface and the fitting accuracy between the valve stem and the valve seat need to be strictly controlled. During the machining process, high-precision machining equipment such as CNC lathes and machining centers should be used, and regular maintenance and calibration of the equipment should be carried out to ensure the stability of machining accuracy. In addition, dimensional inspection of the machined components should be conducted to ensure they meet the design requirements.

• Control of assembly quality: Assembly is a key link in the manufacturing process of the wafer-type butterfly valve with centerline lugs. During assembly, operations should be strictly in accordance with the assembly process requirements to ensure the correct installation and fitting of all components. For example, the installation of the valve seat should ensure its tight fit with the sealing surface of the valve body, and the installation of the valve stem should ensure that its concentricity and fitting clearance with the valve seat meet the requirements. Meanwhile, sealing tests and operational performance tests should be conducted on the assembled valve to ensure its sealing performance and operational flexibility.

III. Quality Inspection Methods

• Appearance inspection: Appearance inspection is the first step in quality inspection, mainly checking whether there are defects such as cracks, sand holes, and air holes on the valve surface, and whether the surface treatment meets the requirements. For example, for valves with surface coating, the uniformity and adhesion of the coating should be inspected to ensure that the coating can effectively protect the valve from corrosion.

• Dimensional inspection: Dimensional inspection is an important means to ensure the machining accuracy of valve components. Inspection tools such as vernier calipers, micrometers, and coordinate measuring machines can be used to measure various key dimensions of the valve, such as the size of the valve body's sealing surface and the diameter and length of the valve stem, to ensure they meet the design drawings and standard requirements.

• Sealing test: The sealing test is a key link in detecting the sealing performance of the wafer-type butterfly valve with centerline lugs. Usually, the method of water pressure test or air pressure test is adopted. The valve is placed under test pressure, and whether there is leakage at the sealing parts is observed. For different media and working pressures, appropriate test pressure and test medium should be selected according to relevant standards. For example, for butterfly valves in drinking water systems, water is usually used as the test medium, the test pressure is 1.5 times the nominal pressure, and the duration is not less than 5 minutes to ensure the sealing performance of the valve in actual use.

• Operational performance test: The operational performance test mainly checks whether the valve opens and closes flexibly and whether the operating torque meets the requirements. Tests can be conducted through manual operation or using an actuator, and the torque changes during the opening and closing of the valve are recorded to ensure its operational performance meets the design requirements. For large-diameter or high-pressure butterfly valves, cycle tests should also be conducted to simulate the frequent operation of the valve in actual use and verify the stability and reliability of its operational performance.

• Material inspection: For the quality control of raw materials, methods such as spectral analysis and chemical analysis can be used to detect whether their chemical composition meets the standard requirements. At the same time, mechanical property tests such as tensile tests and hardness tests should be conducted on raw materials to ensure their mechanical properties meet the specified indicators. In addition, for non-metallic materials such as rubber, aging tests and medium resistance tests should be carried out to evaluate their performance changes during long-term use.