Technical requirements for the most popular pneuma

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Technical requirements for purchasing pneumatic valves (II)

4 The operating mechanism of pneumatic valve

4.1 the opening and closing direction of pneumatic valve during operation should be closed clockwise

4.2 since the pneumatic valve in the pipe is often opened and closed manually, the number of opening and closing turns should not be too many, even the large-diameter valve should also be within the turn

4.3 in order to facilitate the opening and closing operation of one person, the maximum opening and closing torque should be 240n-m under the pressure of the plumber

4.4 the opening and closing operating end of pneumatic valve should be square tenon, with standardized size, and face the ground, so that people can operate directly from the ground. Valves with wheel discs are not suitable for underground pipes

4.5 display panel of pneumatic valve opening and closing degree

① the scale line of pneumatic valve opening and closing degree should be cast on the gearbox cover or on the shell of the display panel after changing the direction, all face the ground, and the scale line should be painted with fluorescent powder to show eye-catching

② stainless steel plate can be used when the material of the indicating dial needle is well managed, otherwise it is painted steel plate, and aluminum sheet cannot be used

③ the indicator needle is eye-catching and firmly fixed. Once the opening and closing adjustment is accurate, it should be locked with rivets

4.6 if the pneumatic valve is buried deeply and the distance between the operating mechanism and the display panel from the ground is ≥ 1.5m, the extension rod facility should be set and fixed firmly, so that people can observe and operate from the ground. In other words, the valve in the pipe should not be operated in the well

5. Performance test of pneumatic valve

5.1 when the valve is manufactured in batches of a certain specification, the following performance tests should be entrusted to authoritative institutions:

① the opening and closing torque of the valve under working pressure

② continuous opening and closing times that can ensure tight valve closure under working pressure

③ detection of flow resistance coefficient of valve under pipeline water delivery condition

5.2 the following tests should be carried out before the valve leaves the factory:

① when the valve is open, the valve body should bear the internal pressure test of twice the working pressure value of the valve

② when the valve is closed, both sides bear 1.1 times the working pressure of the valve respectively, and there is no leakage; However, the leakage value of metal sealed butterfly valve is not greater than the relevant requirements

6. Internal and external anti-corrosion of pneumatic valve

6.1 inside and outside the valve body (including the variable-speed transmission box), first of all, the ball should be thrown to remove sand and rust, and strive to electrostatic spray powder non-toxic epoxy resin, with a thickness of more than 0.3mm. When it is difficult to electrostatic spray non-toxic epoxy resin on extra large valves, it is also necessary to brush and spray non-toxic epoxy paint of similar test standards and specifications

6.2 the interior of the valve body and all parts of the valve plate require comprehensive corrosion prevention. On the one hand, it will not rust when immersed in water, and there will be no electrochemical corrosion between the two metals; On the other hand, the smooth surface reduces the overflow resistance

6.3 the sanitary requirements of epoxy resin or paint for anti-corrosion in the valve body should have the test report of the corresponding authority. Chemical and physical properties shall also meet relevant requirements

7. Pneumatic valve packaging and transportation

7.1 both sides of the valve should be set with light blocking plates for fixation

7.2 Small diameter valves shall be "Historically, straw ropes should be tied up and transported in containers.

7.3 large diameter valves are also packed in simple wooden frame solid packaging to avoid damage during transportation.

8. The factory manual of pneumatic valves

pneumatic valves are equipment, and the following relevant data should be marked in the factory manual:

valve specification; model; working pressure; manufacturing standard; valve body material; valve stem material; sealing material; valve shaft packing material Quality; Material of valve rod sleeve; Internal and external anti-corrosion materials; Operation start direction; revolutions; Opening and closing torque under working pressure; Name of manufacturer; date of production; Factory number; Weight; Hole diameter, number of holes and center hole distance of connecting flange; The overall length, width and height of the control ruler are indicated in a graphic way. Jinan assaying recently caused the ranking to drop due to the revision of the station; Flow resistance coefficient of valve; Effective opening and closing times; In your local area, we can let you see the relevant data of valve factory inspection and precautions for installation and maintenance

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