A marine stainless steel valve is a device used to control the pressure, flow and flow direction of the fluid in the ship's pipeline to meet the environmental conditions of the ship. A valve is the control device of the fluid pipeline. Its basic function is to connect or cut off the flow of the medium in the pipeline, change the flow of the medium and the flow direction of the medium, adjust the pressure and flow of the medium, and protect the normal operation of the equipment in the pipeline. The failures of marine stainless steel valves generally include failures of valve body bonnets, packing and gaskets.
Common failures and causes of valve bodies and bonnets
The common failures of the valve body and bonnet are nothing more than breakage, sand holes, aging and corrosion. The reasons for these failures may be as follows:
Common failures and causes of valve bodies and bonnets
The common failures of the valve body and bonnet are nothing more than breakage, sand holes, aging and corrosion. The reasons for these failures may be as follows:
- The main reasons for the damage to the valve body and the bonnet are the small safety factor, unreasonable structure, internal stress concentration, poor design factors and poor manufacturing quality, such as uneven thickness, uneven material, too brittle welding seams, great internal stress, improper installation, skewed positions, improper selection of the valve, too high water hammer pressure, poor maintenance, breaking due to not good insulation in the winter and damage due to great external force.
- The cause of sand holes is mainly poor manufacturing quality.
- The cause of corrosion or aging is mainly poor manufacturing quality, poor corrosion protection and maintenance, and not timely replacement and maintenance.
Common failures and causes of packing
The common failures of packing mainly include too small pre-tightening force applied to the packing, failures of fasteners, damage to the sealing surface of the valve stem and failures of packing. The reasons for these failures may be as follows:
- There are several reasons for the pretightening force on the packing being too small: insufficient packing, insufficient filling of packing, wear, aging and improper filling, no preload clearance, skewed pressing sleeve, rust, and mixed impurities making the thread not tighten well.
- The reasons for the failure of the fasteners are: breaking of the glands, pressing nuts, bolts, ears and other parts, being loosened due to vibration, damage due to corrosion, uneven force, excessive force, improper operation of the fastener and poor maintenance.
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