Diaphragm Valve User Manual.doc

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Ⅰ. Applications and main performance parameters 1. The rubber-lined diaphragm valve is suitable for use as a valve element to control the flow of media in pipelines carrying generally corrosive fluids at operating temperatures ≤65°C. 2. Main performance parameters: Model, Bore (mm), Operating pressure (MPa), Test pressure, Test temperature, Sealing strength. G41J-6: 25~150, 0.6, 0.66, 0.9, Room temperature; G41J-10: 25~200, 1.0, 1.1, 1.5, Room temperature. II. Principle of operation and structural features: 3. This valve consists of a valve body, valve cover, valve stem, valve disc, diaphragm, and driving components. The basic structure is shown in Figure 1.4. The valve is opened and closed by rotating the handwheel. When the handwheel is rotated clockwise, the valve disc descends, cutting off the flow path ； Conversely, the valve opens. 5. When diaphragm valves are used in steam pipelines with operating temperatures ≤ 120°C, heat-resistant rubber should be selected for the diaphragm material, and this should be specified when placing the order. Ⅲ. Maintenance, Installation, and Usage Precautions 1. Valves should be stored in a dry and well-ventilated area; stacking them is strictly prohibited. 2. Both ends of the passage for the inventory valve must be sealed to prevent foreign objects from entering the interior and damaging the sealing components. It should also be kept away from oils or other flammable substances. 3. The machined metal surfaces of this valve should be cleaned of dirt and coated with rust preventive oil. The oil cup needs to be regularly filled with lubricating grease. 4. Do not apply any greasy substances to the surface of the gasket layer or rubber diaphragm, to prevent rubber swelling and thus affect the service life of the valve. 5. During storage or when the valve is not in use, turn the handwheel counterclockwise to keep the valve in a slightly open position, thereby preventing the diaphragm from losing its elasticity due to prolonged pressure. 6. During transportation or installation, the slings must not be tied to the handwheel or valve stem. It is also strictly prohibited to collide it with other metals or hard objects to prevent damage to the parts and the rubber lining. 7. Before installation, it is necessary to carefully verify that the operating conditions of the pipeline and the type of medium used are compatible with the applicable range of this valve, in order to avoid unnecessary losses or even accidents resulting from inappropriate selection. 8. Apart from being unsuitable for use in vacuum pipelines, this valve can be installed at any position in the pipeline to allow two-way flow, provided that ease of operation and maintenance is ensured. 9. Before installation, the interior cavity of the valve body should be cleaned thoroughly to prevent dirt from causing blockages or damaging the sealing components, and it is also necessary to check that all the connecting bolts are tightened evenly. 10. During operation, it is necessary to regularly inspect the components in contact with the medium, and replace wear-prone parts periodically based on actual usage conditions. 11. When replacing the diaphragm, care should be taken not to tighten or loosen it too much. 12. If this valve is used in pipelines that operate intermittently, the parts in contact with the medium should be cleaned during periods of inactivity to extend its service life. 13. When manually operating the valve, do not use auxiliary levers to open or close it, to avoid excessive torque that may damage the driving components or sealing parts. 14. Valves that have been overhauled must undergo a sealing test in accordance with relevant testing regulations and pass it before they can be installed after use. -1- IV. Possible Failures and Solutions Possible Failures Causes Solutions Rigid rotation of the handwheel Δ Dirt accumulated on the valve stem or damaged threads Δ Worn or cracked valve stem nut Δ Bent valve stem Δ Damaged bearings Δ Remove dirt, repair the threads, and apply lubricant Δ Replace the valve stem nut Δ Straighten or replace the valve stem Δ Replace the bearings Leakage at the connection between the valve body and the valve cover Δ Inconsistent tightening of the connecting bolts Δ Damaged rubber lining on the valve body Δ Tighten evenly; the valve body needs to be replaced Leakage between the sealing surfaces Δ Dirt accumulated between the sealing surfaces Δ Slight damage to the sealing surfaces Δ Diaphragm is too tight or too loose Δ Severe corrosion or damage to the diaphragm Δ Damaged rubber lining on the sealing surfaces Δ Remove dirt without damaging the sealing surfaces Δ Repair them to their original shape Δ Adjust the tightness of the diaphragm appropriately Δ Replace the diaphragm Δ The valve body needs to be replaced Figure 1: Rubber-lined diaphragm valve -2-