Sanitary diaphragm valves are widely used in industries with high hygiene requirements, such as food, beverage, pharmaceutical, and biotechnology, due to their easy cleaning and sterile operation. Proper use and maintenance are key to ensuring its performance, preventing pollution, and extending its lifespan. The following are the main precautions:

1、 Design selection and installation

1. Material compatibility:

*Confirm that the material of the valve body and diaphragm seal (if applicable) (316L stainless steel) is compatible with the medium being processed (product, CIP/SIP cleaner, sterilizer) to avoid corrosion, leaching, contamination, or diaphragm aging.

*Consider the impact of working temperature range on material properties.

2. Surface smoothness:

*Ensure that the surfaces in contact with the product (valve body cavity, diaphragm contact surface) have sufficient smoothness (usually requiring Ra ≤ 0.8 μ m or better, such as Ra ≤ 0.4 μ m) to reduce microbial adhesion and facilitate cleaning.

*Check whether the inner surface of the welding or connection is smooth and free of defects such as pits and cracks.

3. Structural design:

*Choose a truly self draining design to ensure that the medium does not remain trapped.

*Select the correct connection method (such as clamps, threads, welding, flanges) according to the process requirements to ensure reliable connection, sealing, and easy disassembly and cleaning.

*Confirm that the valve size (diameter) meets the requirements for flow rate and pressure drop.

4. Installation:

*Cleanliness: Before installation, ensure absolute cleanliness inside the valve and connected pipelines, removing all protective grease, debris, welding slag, and other contaminants. Follow strict cleanroom installation procedures.

*Direction: It can usually be installed in any direction, but the best practice is to have the valve stem vertically upward (with the actuator at the top). This helps to empty the medium, reduce fluid accumulation at the diaphragm pit, and prevent the actuator from bearing unnecessary stress. If horizontal installation is necessary, ensure that the actuator is not facing downwards.

*Support: For larger or heavier valves (especially those with pneumatic/electric actuators), provide appropriate pipeline support to avoid excessive pipeline stress on the valve, which may cause leakage or damage.

*Alignment: Ensure that the flange or clamp is correctly aligned when connecting the pipeline to avoid twisting the valve body.

*Diaphragm pre tightening force: Install the diaphragm and valve cover correctly according to the manufacturer's instructions to ensure that the diaphragm is evenly stressed and reaches the specified pre tightening force. Tightness can accelerate diaphragm wear and fatigue, while looseness can lead to leakage.

2、 Operation usage

1. Operating pressure and temperature:

*Strictly adhere to the nominal working pressure (PN10-PN16) and temperature (-10 ℃ -150 ℃, select the corresponding diaphragm temperature according to different temperatures) range of the valve. Pay special attention to the maximum temperature and pressure that the diaphragm material can withstand.

*Avoid severe pressure fluctuations or water hammer impacts, which may damage the diaphragm or valve body.

2. Opening and closing operation:

*Avoid throttling use: Sanitary diaphragm valves are designed for fully open or fully closed states and are not suitable for use as throttling valves. Prolonged partial opening can accelerate diaphragm wear (media flushing), generate vibration and noise, and may make local areas difficult to clean.

*Smooth operation: When manually operating, the valve should be opened or closed smoothly to avoid strong impact. When using the actuator, ensure that its speed is set appropriately.

*Confirm in place: * When closing, ensure that the diaphragm is tightly pressed against the edge of the weir to form a seal; When opening, make sure the diaphragm is lifted away from the flow channel.

3. Medium state:

*Pay attention to whether the medium contains solid particles, fibers, or crystals. Although diaphragm valves can handle some suspended solids, particles that are too large or hard may scratch the diaphragm or sealing surface. Pre filter if necessary.

*Avoid excessive friction and thermal stress on the diaphragm caused by dry operation of the medium (especially at high temperatures).

3、 Cleaning and Sterilization (CIP/SIP)

1. Follow validation procedures: Cleaning and sterilization procedures must be validated to ensure effective removal of residues and microorganisms. The design of the valve must support these procedures.

2. CIP (In Place Cleaning):

*Ensure that the cleaning solution (acid, alkali, water) can wet all surfaces inside the valve.

*Ensure sufficient flow rate, velocity, concentration, temperature, and cleaning time.

*After cleaning, it is necessary to rinse with clean water to remove any residual cleaning agents.

3. SIP (In Situ Sterilization):

*Confirm that all components of the valve (especially the diaphragm) can withstand sterilization temperatures (such as 121 ℃ or higher steam) and pressures.

*Ensure that steam can smoothly pass through the valve and reach all surfaces that require sterilization, and eliminate air (condensate discharge is unobstructed).

*Strictly adhere to the requirements of sterilization temperature, pressure, and holding time.

*The cooling process after sterilization should be smooth to avoid valve deformation or damage caused by vacuum or rapid cooling.

4. Avoid chemical corrosion/aging: * Ensure that the cleaning and sterilizing agents used do not corrode the valve body or accelerate the aging of the diaphragm/seal.

4、 Maintenance and upkeep

1. Regular inspection:

Diaphragm state: This is the most critical point! Regularly check whether the diaphragm has:

*Cracks, incisions, perforations

*Deformation, bulging, and indentation

*Hardening, softening, and loss of elasticity

*Color change (may indicate aging or chemical erosion)

*Surface wear and polishing

*Leakage: Check if there is any leakage (internal leakage) when the valve is closed.

*Valve body/valve cover: Check for corrosion, wear, and mechanical damage.

*Execution mechanism: Check whether the air source of the pneumatic actuator is clean and dry, and whether the cylinder leaks; Check the operating status of the electric actuator; Check if the manual operation is smooth.

*Connectors: Check if the clamps, bolts, and sealing rings (if applicable) are intact and securely fastened.

5、 Storage

1. Clean and dry: Valves (whether new or disassembled) should be stored in a clean and dry environment to avoid dust and moisture pollution.

2. Protection: Import and export should be sealed with clean protective covers. The diaphragm should be in a relaxed state to avoid plastic deformation or stress concentration caused by prolonged compression.

3. Avoid the environment: stay away from direct ultraviolet radiation, ozone sources, high or low temperatures, which can accelerate the aging of membranes and seals.