Repair and assembly of meibiao valve [2014-12-03

Having a long service life and no maintenance period will depend on the following factors: normal working conditions, harmonious temperature/pressure ratios, and reasonable corrosion data

Note:

The pressure fluid in the body of the ball valve is still present in the closed state

Relieve pipe pressure and keep valve in open position before repair and assembly of valve

Disconnect the power supply or gas source before repair and assembly of the valve

Disconnect the actuator from the bracket prior to repair

The demolition and decomposing operation can be carried out only when the upper and lower pipes of the ball valve are found to be free of pressure

The sealing surface of the parts must be carefully avoided when decomposing and reassembling, especially non-metal parts. Special tools should be used when the o-ring is removed

Bolts in the flange must be tightened symmetrically, gradually and uniformly, moisture sensor probe, stainless steel electric heat pipe PT100 sensor, cast aluminum heater, heating ring and fluid electromagnetic valve

The 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). Clean non-metal parts with clean water or alcohol

The individual parts that separate can be cleaned by immersion washing. Metal parts with undecomposed nonmetal parts can be cleaned with clean, fine and clean soiled silks with detergent (to avoid fiber falling off and sticking to the parts). When cleaning, all the grease, dirt, glue, dust, etc. that adhere to the wall surface must be removed

The non-metal parts should be taken out of the cleaning agent immediately after cleaning and should not be soaked for a long time

After cleaning, the cleaned wall should be assembled after the detergent has volatilized (it can be cleaned with non-immersed silks), but it should not be used for a long time, otherwise it will rust and be polluted by dust

The new parts also need to be cleaned before assembly

Run lubricated with grease. The grease shall be compatible with ball valve metal material, rubber parts, plastic parts and working medium. When the working medium is gas, for example, special 221 grease can be used. Apply a thin layer of grease to the surface of the sealing groove, a thin layer of grease to the rubber seal, and a thin layer of grease to the sealing cover and friction surface of the valve stem

Dust and other impurities, foreign substances and other pollution, adhesion or retention on the surface of parts or into the inner cavity shall not be allowed during assembly

1) the stuffing should be tightened

Tighten stem nut again if microleakage occurs in packing area.

Note: do not lock too tight, usually another 1/4 ~ 1 turn lock, leakage will stop.

2) replace seats and seals

A), remove the

Keep the valve in a semi-open position to flush and remove potentially dangerous substances from inside and outside the valve body.

Close the ball valve, remove the connecting bolts and nuts from the flange on both sides, and remove the valve completely from the line.

Remove drive device in sequence - actuator, connecting bracket, anti-loose washer, stem nut, butterfly spring, gannan, wear-resistant disc, stem packing.

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

Make sure the ball is in the "off" position, which makes it easier to take it out of the body and then out of the seat.

Gently push the stem down from the hole in the valve body until it is fully removed, then remove the o-ring and stuffing under the stem.

Note: please operate carefully to avoid rubbing the stem surface and sealing parts of the valve body stuffing box.

B) reassemble

Clean and inspect the removed parts. It is strongly recommended to replace the seat and bonnet gaskets with spare parts.

Assemble in the opposite order of disassembly.

Cross lock flange connection bolts with specified torque.

Lock stem nut with specified torque.

After installing the actuator, enter the corresponding signal and drive the valve core to rotate by rotating the stem to open and close the valve.

If possible, perform pressure seal and performance tests on the valve in accordance with relevant standards prior to reloading the pipe.

1, the principle of

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

2. Applicable places

A low pressure, small diameter pipe used to cut off water flow and change the distribution of water flow or a place requiring quick opening and closing