Leakage of valve body and bonnet

Reason:

1. The casting quality of cast iron parts is low, and there are problems such as sand holes, loose organization and slag inclusion on the valve body and valve cover body;

2, the day cold frost crack;

3, the welding is not good, there are slag inclusion, not welding, stress cracks and other defects;

4. The cast iron valve is damaged after being hit by a heavy object.

Maintenance tips:

1, improve the casting quality, before installation in strict accordance with the provisions of the strength test;

2, the temperature is in.0Temperature or 0 ℃ below the valve, should take insulation or mixing heat, stop the use of the valve to drain the water;

3. The welds of the valve body and the bonnet composed of welding shall be carried out according to the relevant welding operation procedures, and the flaw detection and strength test shall be carried out after welding;

4. It is forbidden to push and place heavy objects on the valve, and it is not allowed to hit cast iron and non-metallic valves with hand hammer. The installation of large-diameter valves should have brackets.

Leakage at the packing

The leakage of the valve, the packing accounted for a great proportion.

Reason:

1. Improper selection of packing, not resistant to medium corrosion, not resistant to the use of high pressure or vacuum, high temperature or low temperature;

2. Improper installation of packing, there are problems such as replacing large with small, poor spiral winding joints, tightening and loosening;

3, the filler exceeds the use period, has been aging, loss of elasticity;

4, the valve stem precision is not high, there are bending, corrosion, wear and other defects;

5. The number of packing rings is insufficient, and the gland is not pressed;

6, the gland, bolts, and other parts are damaged, so that the gland can not be pressed;

7, improper operation, excessive force, etc;

8, the gland tilt, the gap between the gland and the stem is too large or too small, resulting in valve stem wear, packing damage.

Maintenance tips:

1. The material and type of the filler shall be selected strictly according to the working conditions;

2, according to the relevant provisions of the correct installation of packing, packing should be placed ring by ring compression, joints should be 30 ℃ or45℃;

3. The filler with too long service life, aging and damage should be replaced in time;

4, stem bending, wear should be timely straightening, repair, serious damage to the timely replacement;

5, the packing should be installed according to the specified number of turns, the gland should be symmetrical and evenly tight, the pressure sleeve should have5mmAbove pre-tightening clearance;

Damaged glands, bolts and other parts should be repaired or replaced in time;

7, strictly abide by the operating rules, in addition to the impact type handwheel, with uniform speed normal force operation;

8. The gland bolts should be tightened evenly and symmetrically. If the gap between the gland and the valve stem is too small, the gap should be appropriately expanded; the gap between the gland and the valve stem is too large and should be replaced.

Leakage of sealing surface

Reason:

1, the sealing surface grinding is not smooth, can not form a close line;

2. The top center of the connection between the valve stem and the closing part is suspended, incorrect or worn;

3. The valve stem is bent or the assembly is not correct, so that the closing part is skewed or not in the middle;

4. Improper selection of the material quantity of the sealing surface or failure to select the valve according to the working conditions.

Maintenance tips:

1. Correctly select the material and type of gasket according to the working conditions;

2, carefully adjusted, smooth operation;

3. The bolts should be screwed evenly and symmetrically, and a torque wrench should be used if necessary. The pre-tightening force should meet the requirements and cannot be too large or small. There shall be a certain pre-tightening clearance between flange and threaded connection;

4. Gasket assembly should be aligned and evenly stressed. Overlapping and double gaskets are not allowed for gaskets;

5, static sealing surface corrosion, damage processing, processing quality is not high, should be repaired, grinding, coloring inspection, so that the static sealing surface meets the relevant requirements;

6. When installing the gasket, pay attention to cleaning. The sealing surface should be cleaned with kerosene, and the gasket should not fall to the ground.

high pressure valve

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    Wuhan Xiete Valve Technology Co., Ltd.Focus on all kinds of valves,Filter,Gas drainer,Throttle orifice plateIt is a professional manufacturing enterprise integrating R & D, production, sales and after-sales, with 20 years of rich experience in the industry. It owns the Xiete valve brand, builds the best R & D professional team in the industry, and has a number of independently designed and developed patented products. Provide customers with the bestValve function customization solution, and has successfully provided professional design customization services for many enterprises and institutions. At the same time, Wuhan Xiete Valve Technology Co., Ltd. has obtained ISO9001 quality system certification and TS special equipment license. Our product types, complete styles, quality assurance, factory direct sales, economical, convenient and fast to provide customers with one-stop service!

 

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