• Common malfunctions and their causes of general & automatic valves
Common malfunctions and their causes of general & automatic valves

Common malfunctions and their causes of general & automatic valves

  • 12 11, 2018

Common malfunction and its causes of general valves 

1. Causes & Maintenance Methods of Stuffing Box Leakage
Causes of Stuffing Box Leakage Maintenance Methods
Incorrect Packing (Such as spinning the tube) Pack correctly.
Deformation, Corrosion or Rust of the Valve Stem Repair or change it for a new one.
Aging of the Stuffing Change the stuffing.
Inappropriate Operation or Pushing too Hard Operate stably.

2. Causes & Maintenance Methods of Valve Stem Malfunction
Causes of Valve Stem Malfunction Maintenance Methods
Damage, Corrosion of Valve Stem Replace the part.
Bent or Twisted Valve Stem Do not pry handwheel with long handled tools when the valve is hard to open; Replace the valve stem.
Slant Valve-Stem Nut Replace the part or the valve.
Rusty and Stuck Outdoor Valve Enhance maintenance; Rotate the handwheel regularly.

3. Causes & Maintenance Methods of Leak Seal
Causes of Leak Seal Maintenance Methods
Abrasion of Sealing Surface, Minor Corrosion Regularly grind it.
Improper Closing, Bad Connection with Sealing Surface Slowly open and close it a couple of times.
Bent or Twisted Valve Stem, Sealing Surfaces not Focusing on the Center Line Repair or replace.
Impurities in Valve Opening Open the valve, clean the impurities, and then slowly turn it off; Install a filter if necessary.
Loose Connection among Seal Ring, Valve Body and Valve Clack Repair.
Loose Connection Between Valve Clack and Valve Stem Repair or replace the part.

4. Causes & Maintenance Methods of Other Malfunctions
Other Malfunctions Causes Maintenance Methods
Gasket Leak Inadaptable Gasket, Losing Efficacy Because of the Affection of Media in Daily Used Change to an adaptable one.
Cracked Valve Damage from Cryogenic Temperature, Pushing too Hard Preserve heat, install evenly.
Broken Handwheel High Impact, Pry with Long Handled Tools, Attrited Chamfer  Prevent hitting, evenly open in the correct direction, rasp the square hole or replace the handwheel.
Cracked Gland Unbalanced Force in Tightening the Gland Symmetrically screw down the nut.
Malfunctioned Disc Rusty Wedge Gate Losing Sealability, Broken Upper Wedge of the Double Disc Regularly grind it or replace to carbon steel wedge.

Common malfunctions & causes of automatic valves

1. Common malfunctions, causes, preventive measures and maintenance methods of check valves
Common Malfunctions of Check Valve Causes Maintenance Methods
Medium Backflow Leaky Sealing Surface Between Valve Core and Valve Body Grind the sealing surface.
Impurities Between Valve Core and Valve Body Remove the impurities.
Unopenable Valve Core Sticky Furr on Sealing Surface Clear away the furr.
Rusty Spindle Polish the spindle.
Frangibility of Valve Clack
Unbalanced Force from Pressure		 Use valve clack with ductile materials.

2. Common malfunctions, causes, preventive measures and maintenance methods of steam trap valves
Common Malfunctions of Steam Trap Causes Maintenance Methods
Unable to Drain Low Pressure of Steam Adjust pressure.
Steam and Condensate Water not Entering the Steam Trap Check if the valve is closed or clogged.
Light Weight of Float Add suitable weight or replace it.
Valve Stem Stuck with Casing Pipe Repair or Replace.
Clogging Clean it, install a filter.
Broken Isothermal Valve Core Replace it.
Steam Leakage Worn Valve Core and Body Grind the sealing surface.
Drain Hole Unable to Close Automatically Check if there's dirt clogging.
Small Volume of Float Increase its volume.
Falling Temperature Condensate Water Remaining Replace the steam trap.
Install a steam trap.

3. Common malfunctions, causes, preventive measures and maintenance methods of relief valves
Common Malfunctions of Relief Valve Causes Maintenance Methods
Unstable Pressure Impulse-type: Unsuitable Valve Diameter, High Pressure Difference Change to a proper relief valve.
Spring-loaded Type: Unfitted Regulating Spring Change to a proper regulating spring.
Valve Clogging Impurities Remove the impurities, install a filter in front of the valve.
Rusty Plunger Repair the plunger
Useless Valve Rusty Plunger Repair the plunger
Broken Spring (under the  valve clack of the main valve) Replace the spring.
Valve Handle (impulse-type) Stuck in the Closed Position Overhaul.
Impurities or Severe Corrosion Between the Valve Clack and Valve Body Remove the impurities, regularly grind the sealing surface.
Diaphragm Losing Efficacy Replace it.
Unadjustable Pressure Malfunction of Regulating Spring Replace.
Leakage on the Cap, Unstable Pressure Overhaul, replace the gasket.
Worn or Corroded Plunger, Air Cylinder Overhaul the air cylinder, change the piston ring.
Condensate Water Loosen the plug, empty the condensate water.

4. Common malfunctions, causes, preventive measures and maintenance methods of safety valves​​​
Common Malfunctions of Safety valve Causes Maintenance Methods
Leaking Sealing Surface Impurities or Worn Sealing Surface Between the Valve Core and Body Remove the impurities or grind the surface.
Obliquitous Center Line of the Valve Rod Rectify the center line.
Unopenable Valve even with Exceeded Working Pressure Stuck Lever or Rusty Dowel Overhaul
Moved Hammer (lever-type) Adjust the position of the hammer.
Distortion or Losing Efficacy of the Spring due to High Temperature Replace the Spring
The Valve Core Pasting on the Valve Body Regularly test exhaust emissions.
Valve Opening Without Sufficient Working Pressure The Lever Hammer Moving Inward Adjust its position.
Not Springy Enough (spring-type) Tighten up or replace the spring.
Unable to Close Automatically Obliquitous Lever (lever-type) Repair.
Curve Spring (spring-type) Adjust the spring.
Obliquitous Valve Core or Valve Rod Adjust.
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