What are the areas of attention for the daily maintenance of ball valves?

With a longer service life and maintenance-free period, it will depend on the following factors: normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data.

When the ball valve is closed, there is still pressure fluid inside the valve body.

Before maintenance: release pipeline pressure and keep valve in open position; disconnect power or gas source; disconnect actuator from bracket

Before disassembly and decomposition operation can be carried out, it must be ascertained that the upstream and downstream pipes of the ball valve have been removed pressure.

When decomposing and reassembling, care must be taken to prevent damage to the sealing surface of parts, especially non-metallic parts. Special tools should be used when removing O-rings.

Bolts on flanges must be tightened symmetrically, step by step and evenly during assembly.

Cleaning agent should be compatible with rubber parts, plastic parts, metal parts and working media (such as gas) in ball valves. When the working medium is gas, the metal parts can be cleaned with gasoline (GB484-89). Non-metallic parts should be removed from the cleaning agent immediately after cleaning with pure water or alcohol. It is not allowed to soak and clean for a long time and assemble after volatilization of the cleaning agent on the washed wall (which can be wiped with silk cloth without soaking detergent), but it should not be shelved for a long time. Otherwise, new parts which will rust and be polluted by dust should not be allowed to clean and assemble before assembly. Debris, fibers, grease (except for specified use) dust and other impurities, foreign bodies and other contamination, adherence or stay on the surface of the parts or enter the cavity, if there is micro-leakage at the filler, the valve stem nut must be locked again.

Note: Do not lock too tightly, usually lock 1/4 to 1 turn again, the leak will stop.

A), dismantling

Make the valve in the half-open position, flush and remove the dangerous substances that may exist inside and outside the valve body.

Close the ball valve, remove the connecting bolts and nuts on both flanges, and then remove the valve completely from the pipeline.

Disassemble the driving device in sequence - actuator, connecting bracket, anti-loosening washer, stem nut, butterfly spring, Gnan, wear-resistant plate, stem packing.

Remove the cover connecting bolts and nuts, separate the cover from the body, and remove the cover washer.

Confirm that the ball is in the "off" position, which makes it easier to remove it from the valve body and then from the seat.

The stem is pushed downward from the hole in the body until it is completely removed, and then the O-ring and the packing under the stem are removed.

Note: Please operate cautiously to avoid scratching the stem surface and the sealing part of the body packing box.

B) reassembly

Clean and inspect the parts and remove them. It is strongly recommended to replace the seats and cover gaskets of spare parts packages.

Assemble in reverse order of disassembly.

Cross-lock flange bolts with specified torque.

Lock the stem nut with specified torque.

After the actuator is installed, the corresponding signal is input to drive the spool by rotating the stem.

Rotate to open and close the valve.

If possible, test the pressure seal and performance of the valve according to the relevant standards before installing the pipeline.

1, principle

The opening and closing part of the ball valve is a sphere, which rotates around the center line of the valve body to open and close.

2. Place of application

Low pressure, small caliber pipes are used to cut off water flow and change the distribution of water flow or places requiring quick opening and closing.

3, characteristics

1) Small flow resistance;

2) simple structure;

3) Small size and light weight;

4) The sealing surface material of the ball valve is plastic and has good sealing performance.

5) Easy to operate, quick to open and close, easy to control over a long distance;

6) Easy maintenance, sealing rings are generally mobile, easy to disassemble and replace;

7) When fully open or fully closed, the sealing surface of the ball and seat is isolated from the medium, and the medium passing through will not cause the erosion of the sealing surface of the valve.

4, classification1) The commonly used ball valves are divided into floating ball valves, fixed ball valves and lifting rod ball valves according to their working principles.2) Ball valves can be divided into straight-through type, three-way type and right-angle type according to their channel position. The latter two kinds of ball valves are used to distribute the medium and change the flow direction of the medium.5. Key Points of Construction and Installation1) Installation location, height, import and export direction must meet the design requirements, the connection should be firm and tight.2) All kinds of manual valves installed on the insulation pipeline shall not have downward handles.3) Appearance inspection must be carried out before the valve is installed. The nameplate of the valve should conform to the current national standard "General Valve Mark" GB 12220. For valves with working pressure greater than 1.0 MPa and cutting off effect on main pipe, strength and tightness test should be carried out before installation, and the valves can be used only after they are qualified. In the strength test, the test pressure is 1.5 times of the nominal pressure, and the duration is not less than 5 minutes. The valve shell and packing should be qualified without leakage. The test pressure is 1.1 times of the nominal pressure in the tightness test, and the test pressure should meet the requirements of GB 50243 standard for the duration of the test, with no leakage on the valve sealing surface as the qualification.4) Install gasket between valve flange and pipeline flange according to pipeline design requirements.5) Ball valves with belt drive mechanism shall be installed according to the specifications of the product.