During the installation process of sanitary diaphragm valves, some common problems may arise, which may affect the performance and lifespan of the valves. The following are the summaries of these problems and the corresponding solutions: 

I. Common Issues Before Installation 

1. Mismatched model and specification 

Question: The operating conditions of the pipeline were not carefully checked against the applicable range of the diaphragm valve, resulting in an incorrect selection of the model and specification. 

Solution: Before installation, it is necessary to carefully verify the operating conditions of the pipeline and the applicable range of the diaphragm valve, ensuring that the selected model and specification are in line with the design requirements. 

2. Insufficient attention paid to the appearance inspection 

Question: The appearance of the diaphragm valve was not thoroughly inspected, resulting in the discovery of damage or deformation of the valve after installation. 

Solution: Before installation, a thorough inspection of the appearance of the diaphragm valve should be conducted to ensure there are no damages, rust, and to check if the diaphragm is intact without any cracks, holes or signs of aging. 

II. Common Issues During Installation 

The connection is not properly fastened. 

Problem: When using bolts to secure the valve body to the pipe flange, insufficient or excessive tightening force was applied, resulting in leakage at the connection point. 

Solution: When using bolts to secure the valve body to the pipe flange, ensure a secure connection but avoid over-tightening which could cause damage. After installation, check if the connection is tight; if it is loose, re-tighten it. 

2. Diaphragm damage 

Question: During the installation process, the diaphragm was damaged due to improper operation or incorrect use of tools. 

Solution: During the installation process, be careful and avoid using sharp tools or exerting excessive force to damage the diaphragm. If the diaphragm is found to be damaged, it should be replaced immediately. 

3. Incorrect installation direction 

Problem: The correct installation direction was not determined according to the installation requirements of the diaphragm valve, resulting in poor valve operation or leakage. 

Solution: Before installation, carefully read the installation manual of the diaphragm valve to ensure that the correct installation direction is determined as per the requirements. After installation, check the opening and closing status of the diaphragm valve to ensure it is flexible and free from any obstruction. 

III. Common Problems After Installation and Their Solutions 

1. Leakage issue 

Reasons: Loose connection, damaged diaphragm, deformed sealing surface, etc. 

Solution measures: Check if the connection points are securely fastened. If they are loose, re-tighten them; Check if the diaphragm is damaged. If so, replace it; Check if the sealing surfaces are deformed or damaged. If so, repair or replace them. 

2. Poor opening and closing functionality 

Reason: The operating mechanism is stuck, the diaphragm is too tight, etc. 

Solution: Check if the operating mechanism is flexible. If there is any obstruction, clean it; check if the diaphragm is too tight. If so, adjust its tightness. 

IV. Other Important Notes 

1. Avoid applying grease: Do not apply grease to the rubber lining layer of the sanitary diaphragm valve and the surface of the rubber diaphragm to prevent the rubber from swelling and affecting the service life of the diaphragm valve. 

2. Protect the handwheel or transmission mechanism: The handwheel or transmission mechanism must not be used for lifting purposes and must not be subject to any collisions. 

3. Correct operation: When operating the sanitary diaphragm valve manually, do not use an auxiliary lever as it may cause excessive torque and damage the driving components or sealing parts. 

4. Storage requirements: Hygienic diaphragm valves should be stored in a dry and well-ventilated indoor area. They must not be piled up. The end channels of the stored diaphragm valves must be sealed, and the valve components should be in a slightly open state. 

In conclusion, when installing a sanitary diaphragm valve, several aspects need to be taken into consideration, including preparation before installation, operations during installation, and inspections and tests after installation. Only by ensuring that each step is correct can the normal operation and service life of the diaphragm valve be guaranteed.