How to Choose Electric Ball Valves? - Part Two

IV. Performance tests of electric ball valves
1. When the electric ball valve of a certain specification is manufactured in batch, the following performance tests shall be carried out:
① The opening and closing torque of the electric ball valve under the working pressure condition
② The continuous opening and closing times can ensure the close tightness of the electric ball valve under the working pressure condition.
③ The flow resistance coefficient test of the electric ball valve under the water conveyance condition of the pipeline

2. The following tests shall be carried out for the electric ball valve before delivery:
① When the electric ball valve is opened, the valve body shall bear the internal pressure test of twice the working pressure value of the electric ball valve.
② When the electric ball valve is closed, both sides shall bear 1.1 times of the working pressure value of the electric ball valve respectively without leakage. However, the leakage value of the metal sealed butterfly valve shall not be greater than the relevant requirements.

V. Operating mechanism of electric ball valves
1. The opening and closing direction of electric ball valve should be closed clockwise.
2. Since the electric ball valve in the pipe network is often opened and closed manually, the number of opening and closing should not be too much, even the large diameter electric ball valve should be within 200-600 rpm.
3. In order to facilitate the opening and closing operation of one person, the opening and closing torque should be 240n-m under the pipe working pressure condition.
4. The opening and closing operation end of electric ball valves should be square tenon. The size should be standardized, so that people can operate directly from the ground. The electric ball valve with a disc is not suitable for underground pipelines.
5. Indication panel of opening and closing degree of electric ball valves
① The scale line of opening and closing degree of electric ball valves shall be casted on the gearbox cover or the shell of display panel after changing directions. All face the ground, and the scale line shall be painted with fluorescent powder to show eye-catching.
② The material of indication disc needle can be made of stainless steel plate under better management, otherwise it is painted steel plate, and aluminum sheet is not allowed to be used.
③ The indicator disc needle is eye-catching and firmly fixed. Once the opening and closing adjustment is accurate, it should be locked with rivets.
6. If the electric ball valve is buried deeply and the distance between the operating mechanism and the display panel from the ground is more than 1.5m, the extension rod facilities shall be set and fixed firmly so that people can observe and operate from the ground. In other words, the opening and closing operation of electric ball valves in the pipeline is not suitable for well operation.

VI. Packaging and transportation of electric ball valve
1. Both sides of electric ball valve shall be provided with light blocking plates for fixation.
2. Medium and small caliber electric ball valves shall be bundled with straw ropes and transported in containers.
3. The large diameter electric ball valve is also packed with simple wooden frames to avoid collision and damage during transportation.

VII. Internal and external corrosion protection of electric ball valve
1. The inside and outside of the valve body (including transmission box) shall be shot blasted, and snad and rust should be removed. Electrostatic spraying of powdered epoxy resin with thickness of more than 0.3mm shall be made. When it is difficult to spray epoxy resin for super large electric ball valves, similar epoxy paint should be applied and sprayed.
2. The inside of the valve body and all parts of the valve plate are required to be fully protected against corrosion. On the one hand, immersion in water will not cause corrosion, and there will be no electrochemical corrosion between the two metals. On the other hand, the smooth surface will reduce the water resistance.
3. The corresponding inspection report shall be provided for the hygienic requirements of epoxy resin or paint for anticorrosion inside the valve body. The chemical and physical properties should also meet the relevant requirements.

8. Factory instructions of electric ball valves
Electric ball valves are devices, and the following relevant data shall be indicated in the factory instruction: electric ball valve specifications, models, working pressure, manufacturing standards, valve body materials, valve stem materials, sealing materials, valve shaft packing materials, valve rod sleeve materials, internal and external anti-corrosion materials, operation starting directions, revolution, opening and closing torque under working pressure, manufacturer names, dates of manufacture, weights, diameters, numbers of hole and center hole distances of connecting flanges, control dimensions of overall length, width and height indicated in diagram, flow resistance coefficient of electric ball valves, effective opening and closing times, relevant data of factory inspection of electric ball valves and precautions for installation and maintenance.