The cleaning methods for sanitary butterfly valves are mainly divided into two categories: online cleaning (CIP) and offline cleaning (manual cleaning).
The specific operating methods and precautions are as follows:
CIP method for online cleaning
CIP cleaning process
Valve status: Ensure that the valve is fully open to avoid the formation of cleaning dead corners in the flow channel.
Cleaning parameters: Use a cleaning solution compatible with the medium, and cycle the cleaning according to the pressure and temperature set by the system for no less than 15 minutes.
Cleaning solution selection: Usually includes alkaline washing (1% -2% concentration), acid washing, etc., temperature controlled at 60-80 ℃, pressure 0.3-0.5MPa.
Final rinsing: After cleaning, rinse residual cleaning agents with purified water or clean water to prevent chemical substances from corroding the valve body or contaminating subsequent media
Key Operating Points
Repeatedly switch: When cleaning, the butterfly valve should be repeatedly "fully open fully closed" 3-5 times to allow the cleaning solution to fully flush the contact gap between the valve plate and the valve body.
Pressure control: Ensure that the cleaning pressure reaches 0.3-0.5MPa for no less than 30 minutes.
Temperature monitoring: Maintain the temperature of the cleaning solution within the range of 60-80 ℃
Offline cleaning (manual cleaning) method
Disassembly and cleaning steps
Safety preparation: Close the upstream and downstream valves, release the internal pressure of the valve body, and disconnect the power or gas source.
Disassembly sequence: Disassemble the body, valve stem, and seals of the pneumatic butterfly valve.
Cleaning tools: Use a clean cloth, brush, and appropriate cleaning agent for cleaning.
Cleaning agent selection
Gentle cleaner: Avoid using corrosive or abrasive cleaners to prevent damage to the valve surface coating or material.
Special cleaning agent: Select cleaning agents that meet hygiene requirements to avoid adverse effects on pipeline media.
Solvent selection: For gas ball valves and sanitary butterfly valves, gasoline can be used for cleaning; Other components are generally cleaned with water.
Special cleaning requirements
surface treatment
Electrolytic polishing: Some stainless steel butterfly valves may have uneven surfaces, but after electrolytic polishing treatment, a bright, smooth and even effect can be achieved.
Degreasing treatment: All components need to be polished, and there should be no machining burrs on the surface; All components of the valve body undergo degreasing treatment.
Acid pickling passivation: After degreasing is completed, acid pickling passivation is carried out, and the cleaning agent does not contain phosphorus; Rinse clean with pure water after pickling and passivation.
drying method
Compressed air drying: After cleaning, dry the flow channel with clean compressed air (0.2MPa) to avoid the growth of microorganisms due to residual cleaning solution.
Non woven wiping: Use non-woven fabric or precision filter paper dipped in analytical pure alcohol to wipe each component until there is no dirty color.
Verification and maintenance after cleaning
performance testing
Sealing test: After closing the valve, apply working pressure to one side of the pipeline and observe if there is any leakage on the other side.
Surface inspection: Touch the inside of the valve body and the surface of the butterfly plate with your hand. If roughness, scratches, or dents are found, they should be repaired in a timely manner.
Flexibility of switch: Manually or electrically operate the valve and observe whether the butterfly plate rotates smoothly without any jamming or abnormal noise.
regular maintenance
Lubrication and maintenance: Add food grade lubricating grease to the valve stem bearing area once a month to avoid using industrial lubricating grease.
Seal inspection: Regularly inspect the seals for cracks, deformations, hardening, or scratches, and replace them immediately if necessary.
Long term shutdown maintenance: If the valve is not in use for a long time, it needs to be cleaned internally and closed in a semi open state (with the butterfly plate rotating 45 °) to avoid long-term compression and deformation of the seal.
Safety precautions
Operational Security
Pressure release: Before maintenance, the cut-off valve in front of the butterfly valve must be closed, and the butterfly valve that needs maintenance must be opened to release the internal pressure of the valve body.
Electrical safety: Electric or pneumatic butterfly valves must first disconnect the power and gas sources.
Personal protection: Operators should wear rubber gloves for cleaning operations.
Environmental Requirements
Storage conditions: Store in a dry and ventilated environment, avoiding direct sunlight and high temperatures.
Anti corrosion treatment: The valve body surface can be coated with a thin layer of food grade anti rust oil (only applicable to the outer surface of non-contact media).
By using the above cleaning methods, the hygiene performance and service life of sanitary butterfly valves can be ensured, meeting the strict requirements of industries such as food and pharmaceuticals.
Sampling testing should be conducted after each cleaning to ensure that the cleaning effect meets the standard requirements.
