Oil seal differential pressure valve, also known as the lifting rod gate valve (also known as rod valve). Trapezoidal thread is usually on the lifting rod, through the valve at the top of the nut and the guide groove on the valve body, the rotary motion into a linear motion, that is, the operating torque into the thrust. When the valve is opened, the fluid path is completely clear when the ram height is equal to 1: 1 of the valve diameter, but this position can not be monitored during operation. The actual use is based on the top of the valve stem as a sign, that is, an open position, as its fully open position. To consider the temperature change lock phenomenon, usually in the open to the top position, and then back 1 / 2-1 lap, as a fully open valve position. Therefore, the valve fully open position, according to the gate position (ie travel> to determine.

Soft seal valve general requirements:

1, soft seal gate valve specifications and categories should be consistent with the requirements of the pipeline design documents.

2, the type of soft seal gate valve should be marked on the basis of GB number requirements. If the enterprise standard, should indicate the relevant description of the model.

3, the working pressure of the soft seal gate valve, the required working pressure ≥ pipe, without affecting the price of the premise, the valve can withstand the working pressure should be greater than the actual pressure of the pipeline; soft seal gate valve on any side should be able to withstand the closure of the situation 1.1 times the valve working pressure without leakage; valve open condition, the valve body should be able to withstand the double valve pressure requirements.

4, oil seal valve manufacturing standards, should be based on the national standard number, if the enterprise standards, procurement contracts should be accompanied by corporate documents.

Soft seal gate valve material:

1, the body material, should be ductile iron, cast steel, stainless steel, 316L-based, and indicate the grades and the actual physical and chemical testing of cast iron.

2, stem material, and strive to stainless steel stem (2CR13), large-diameter valve should also be stainless steel embedded valve stem.

3, nut material, the use of cast aluminum brass or cast aluminum bronze, and the hardness and strength are greater than the stem.

4, stem bushing material, the hardness and strength should not be greater than the stem, and in the water soaking conditions with the stem, the valve body does not form electrochemical corrosion.

5, the sealing surface of the material

â‘  different types of soft seal gate valve, seal and material requirements vary;

â‘¡ ordinary wedge gate valve, copper ring material, fixed way, grinding methods should be described;

â‘¢ soft seal gate valve, valve lining rubber material physical and chemical and health testing data;

6, valve shaft packing

â‘  Due to the soft seal gate valve in the pipe network, it is usually not frequent to open and close, requiring the packing to be inactive within a few years, the packing is not aged, and the sealing effect is maintained for a long time;

â‘¡ valve shaft packing should also withstand frequent opening and closing, the sealing effect of the good;

â‘¢ In view of the above requirements, the valve shaft filler for life or do not change for more than 10 years;

â‘£ If the packing needs to be replaced, the pneumatic valve design should consider the measures that can be replaced under the condition of water pressure.

Oil seal differential pressure valve operating mechanism

1, soft seal gate valve opening and closing direction of operation, should be closed clockwise.

2, due to the pneumatic valve in the pipe network, often manual opening and closing, opening and closing speed should not be too much, that is, large-diameter valves should be within 200-600 turn.

3, in order to facilitate a person's opening and closing operations, the plumbing pressure conditions, the maximum opening and closing torque should be 240N-m.

4, soft seal gate valve opening and closing operation side should be square tenon, and size standardization, and facing the ground, so that people can directly operate from the ground. Valves with wheels are not suitable for underground pipe networks.

5, soft seal gate valve opening and closing of the display plate

â‘  soft seal gate valve opening and closing of the scale line should be cast in the gearbox cover or switch the direction of the display after the shell, all toward the ground, the scale line brush on phosphor, to show eye-catching;

â‘¡ indicating the material of the needle plate in the management of better available stainless steel plate, otherwise painted steel, do not use aluminum production;

â‘¢ indicates needle plate eye-catching, fixed firmly, once the opening and closing adjustment is accurate, should rivet lock.

6, If the soft seal gate valve buried deeper, the operating mechanism and the display panel from the ground distance ≥ 1.5m, should be equipped with additional rod facilities, and fixed firmly, so that people from the ground to observe and operate. In other words, pipe network valve opening and closing operation, should not go down to work.

Oil seal differential pressure valve performance testing

1, the valve manufactured in a batch size, the authoritative agencies should be commissioned to test the following properties:

â‘  valve opening and closing moment under the conditions of work pressure;

â‘¡ in the working pressure conditions, to ensure that the valve closed tight opening and closing times;

â‘¢ valve in the pipeline under the water flow resistance coefficient of detection.

2, the valve should be carried out in the factory the following test:

â‘  valve in the open condition, the valve body pressure should withstand twice the pressure test;

â‘¡ closed the valve, both sides were 1.1 times the valve pressure, no leakage; but the metal seal butterfly valve, the leakage value is not greater than the relevant requirements.

Oil seal differential pressure valve inside and outside corrosion

1, the valve body (including variable speed transmission box) inside and outside, the first shot blasting sand rust, and strive to electrostatic spray powder non-toxic epoxy resin, the thickness of 0.3mm above. Extra-large valve electrostatic spraying non-toxic epoxy resin difficulties, should also be brushing, spraying similar non-toxic epoxy paint.

2, all parts of the valve body and the valve plate requires a full anti-corrosion, on the one hand soaked in water will not rust, electrochemical corrosion between the two metals does not produce; two smooth surface to reduce the water resistance.

3, the body of the anti-corrosion epoxy resin or paint the health requirements, there should be the corresponding authority of the test report. Chemical and physical properties should also meet the relevant requirements.

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