Valve factory inspection requirements

When mass manufacturing a certain specification of valve, authoritative institutions should be commissioned to conduct the following performance tests:

1. The opening and closing torque of the valve under working pressure conditions.

2. The continuous opening and closing times that can ensure the valve is tightly closed under working pressure conditions.

3. Detection of flow resistance coefficient of valves under pipeline water delivery conditions.

Valves should undergo the following tests before leaving the factory:

1. When the valve is in the open position, the valve body should withstand an internal pressure test of twice the working pressure value of the valve.

2. When the valve is closed, both sides can withstand 1.1 times the working pressure value of the valve without leakage; But for metal sealed butterfly valves, the leakage value should not exceed the relevant requirements.

Internal and external anti-corrosion of valves:

1. The inside and outside of the valve body (including the gearbox) should first be shot blasted, sandblasted, and rust removed, striving for electrostatic spraying of powder non-toxic epoxy resin with a thickness of at least 0.3mm. When it is difficult to electrostatically spray non-toxic epoxy resin on extra large valves, similar non-toxic epoxy paint should also be brushed or sprayed.

2. The interior of the valve body and various parts of the valve plate require comprehensive anti-corrosion measures. On the one hand, immersion in water will not corrode, and there will be no electrochemical corrosion between the two metals; Smooth surface on both sides reduces water resistance.

3. The hygiene requirements for anti-corrosion epoxy resin or paint inside the valve body should be accompanied by testing reports from relevant authoritative authorities. The chemical and physical properties should also meet relevant requirements.

Valve appearance requirements:

1. The coating on the valve body should be uniform and there should be no peeling or bubbles.

2. The valve body should be kept clean and free from oil stains and other contaminants.

3. The nameplate on the valve body should be clear and legible, with the full name of the manufacturer, production time, factory time, valve specifications and models, the name and number of the valve testing standard, and the inspector number for factory inspection.

4. The valve stem handwheel should indicate the opening and closing direction of the valve, and it should be clear and concise; For one-way valves, the direction of water flow should be clearly indicated on the valve body.

Valve packaging and transportation:

1. Lightweight blocking plates should be installed on both sides of the valve for secure sealing.

2. Small and medium-sized valves should be tied with grass ropes and transported in containers.

3. Large caliber valves also come with simple wooden frame fixation packaging to prevent damage during transportation.