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Requirements of various sealing materials for pneumatic gate valves

This article would like to discuss with you some of the material requirements of pneumatic gate valves, including the

pneumatic gate valve (3)

pneumatic gate valve (3)

material of the valve body, stem, stem bushing, nut, sealing surface and packing of the pneumatic gate valve. Each of them is an important component to ensure the good sealing performance of the valve. The quality of the sealing is the main criterion for evaluating the quality of the valve. Let’s share the standard requirements of various materials for pneumatic valves.
Let’s take a look at the valve body, valve stem, nut and other requirements. The material of the valve body should be mainly ductile iron, and the grade and actual physical and chemical test data of the cast iron should be indicated. The stem material strives to be stainless steel, and large-diameter gate valves should also be stainless steel embedded valve stems. The material of the stem bushing should not be greater in hardness and strength than the stem, and will not form electrochemical corrosion with the stem and valve body under water immersion. The nut material is made of cast lead brass or cast aluminum bronze, and the hardness and strength should be greater than that of the valve stem.
Let’s look at the material of the sealing surface of the pneumatic gate valve. We know that different types of pneumatic valves will require different sealing methods and materials because they are applicable to different working conditions. The sealing material is mainly divided into soft seal and hard seal. The soft seal is mainly an elastic seal based on rubber and plastic, and the hard seal is a rigid metal-to-metal seal. Take the ordinary wedge-type soft-seal gate valve as an example. The manufacturer’s fixing method, grinding method, physical chemistry and sanitary inspection data of the valve plate lining material should be clearly explained. And mark the valve body, the sealing surface material and the valve plate sealing surface material. Their physical and chemical testing data, especially the hygienic requirements, anti-aging performance, and wear resistance of rubber. Take the rubber soft sealing gate valve as an example, usually use nitrile butadiene rubber and EPDM rubber, etc. It is strictly forbidden to mix with reclaimed rubber.
Finally, the valve shaft packing has a great relationship with the sealing performance of the gate valve. Many leaks are caused by improper use of fillers. Since the pneumatic valves in the pipe network are usually opened and closed infrequently, the packing is required to be inactive for several years, the packing does not age, and the sealing effect is maintained for a long time. Therefore, the packing cannot be too tight or too loose. The valve shaft packing should also have a good sealing effect when it is subjected to frequent opening and closing. If the packing needs to be replaced, the pneumatic valve design should consider measures that can be replaced under water pressure. Therefore, the valve shaft packing is not to be replaced or not replaced for more than ten years.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Correct installation method of pneumatic gate valve

Good valve products also need correct use and maintenance to ensure a good working condition and service life of the product, and pneumatic gate valves are no exception. The working state of the pneumatic gate valve directly affects the operation of the engineering system. Pneumatic gate valves have been widely used in metallurgy,

pneumatic gate valve (3)

pneumatic gate valve (3)

petrochemical and other fields. What we want to share today is how to properly use and maintain pneumatic gate valves to maintain their stability and reliability advantages in work. The details are as follows:
First of all, in order to ensure the normal operation of the pneumatic gate valve in the pipeline system and the safe operation of the system, we first need to do some work before the installation. For example, before installing a new valve, check whether the markings on the valve conform to the design requirements. At the same time, the basic error limit, full stroke deviation, return difference, dead zone, leakage rate, etc. are debugged. This is a new valve for pneumatic gate valves. If the pneumatic gate valve in the original system has been overhauled, in addition to completing the above work, the stuffing box and connections of the old gate valve should be checked for tightness. From the on-site use point of view, many problems in the operation of the system are often not caused by the quality of the valve itself, but because of the improper installation of the valve. This also includes factors such as the device environment, improper location and orientation of the device, or unclean piping.

Therefore, the following aspects should be paid attention to when installing the pneumatic gate valve:
1. Waterproof and cooling measures should be taken in the open air or high temperature places with strong sunlight. Where there is an earthquake source, stay away from the earthquake source or increase earthquake-proof measures.
2. Pneumatic gate valve can be installed tilted under special circumstances, but if the tilt angle is large or the weight of the valve itself is too large, it must be reinforced and supported.
3. The pipeline for installing the gate valve should not be too high from the ground. If the pipeline height exceeds 2m, a platform should be set up as far as possible to facilitate the operation of the handwheel and maintenance.
4. Before starting the valve for the first time, the pipeline must be cleaned to remove dirt and welding slag. Because if impurities in the pipeline pass through the valve with the medium at high speed, it is easy to cause damage to the sealing surface and cause leakage. After installation, the valve should also be cleaned to prevent impurities from getting stuck in the valve body. Remember to restore the original neutral position after using the handwheel mechanism.
5. The installation position of the pneumatic gate valve must meet the process requirements. In order to facilitate the later maintenance, it is better to add a bypass line to the valve, which is to continue the production during the maintenance process.
6. The electrical part of the pneumatic gate valve should be implemented in accordance with the construction requirements of the relevant electrical equipment. This should be communicated more with the manufacturer, strictly in accordance with the manufacturer’s technical requirements.
7. The reducer of the actuator of the pneumatic gate valve should be lubricated after disassembly and repair. Generally, low-speed motors should not be disassembled, washed and refueled. After the motor is assembled, check whether the valve position conforms to the valve position opening indication.
The above are some precautions before, during, and after installation of electrical gate valves, which have a very important impact on the service life and use effect of the gate valve, and we need to pay attention to it. For more information about gate valves, please contact Tanghai online customer service for professional answers.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Pneumatic gate valve model preparation method

Pneumatic gate valve model preparation method /naming method /code name modification:
Pneumatic gate valve uses compressed air as the power source. Through the up and down movement of the valve stem, the gate is driven to open and close the valve. It has the advantages of reliable performance, convenient

gate valve

gate valve

operation switching and maintenance, and has been widely used by petroleum, chemical, marine and other departments. For the control of various media. For the application of pneumatic gate valves, structural forms, and valve body materials, users should be familiar with the description of the pneumatic gate valve model preparation to avoid problems such as selecting the wrong model, placing the wrong order, and unclear technical parameters causing exchange and return.
Pneumatic gate valve model preparation instructions are mainly for the detailed explanation of the additional conditions of the gate valve, drive mode, connection form, structural feature, sealing material, pressure level and valve body material. Other customized or special product models are not applicable to this method. , Additional explanation is required. To
Pneumatic gate valve model compilation method:
Additional code for gate valve: WZ means bellows gate valve, DZ cryogenic gate valve, NKZ vacuum gate valve, PZ knife gate valve;
Type of gate valve: Z;
Drive mode: manual without code (usually omitted according to regulations), 2 electro-hydraulic, 3 worm gear, 5-bevel gear transmission, 6 pneumatic, 9-electric;
Connection mode: 4 flange connection, 6 welding, 7 pair clip type;
Structural form: 0 elastic gate, 1 open-rod wedge-type single gate, 2-open-rod wedge-type double gate, 3-open-pole parallel single gate, 4-open-pole parallel double gate, 5 concealed Rod wedge single gate, 6 concealed rod wedge double ram, 7 concealed rod parallel single ram, 9 concealed rod parallel double ram;
Sealing material: W valve body is directly processed, T alloy, X rubber, F fluoroplastic, H-Cr stainless steel, Y cemented carbide, M Monel alloy;
Pressure rating: PN1.0-32Mpa, 16=1.6MPA means the pressure is 16 kg, 150LB-1500LB means the American

Knife gate valve (1)

Knife gate valve (1)

standard pound pressure, 5-63K means the Japanese pressure;
Valve body material: Z-gray cast iron, Q ductile iron, T alloy, C carbon steel, P stainless steel 304, R stainless steel 316, V chromium molybdenum vanadium steel. gas
Description of the model preparation of the moving gate valve:
PZ673H-10P Stainless steel pneumatic wafer type knife gate valve

1. PZ: stands for knife gate valve;
2. 6: It means that the transmission mode is pneumatic;
3. 7: The connection method is a clip-on connection;
4. 3: The structure is an open pole parallel single gate;
5. H: The sealing material is stainless steel;
6, 10: Indicates that the nominal pressure is 1.0MPa;
7. P: indicates that the valve body material is stainless steel.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Working Principle of Pneumatic Gate Valve

Brief introduction of pneumatic gate valve:
The pneumatic gate valve is equipped with a pneumatic actuator, which is driven by compressed air to control the gate valve. The valve core is composed of a wedge-shaped structure and a parallel structure, which is suitable for the emergency cut-off and discharge of gas and liquid pipelines.

pneumatic gate valve (3)

pneumatic gate valve (3)

Working principle of pneumatic gate valve:
When using the air source to operate the gate valve, the small handle of the manual device must be turned to the pneumatic position to open and close the nut and the screw rod. When the compressed air enters from the upper pipeline of the cylinder, the piston and the piston rod in the cylinder are pushed straight When the compressed air enters from the lower pipe, the gas pushes the piston and piston rod in the cylinder to move upwards, and at the same time drives the valve stem to move upwards to open the valve. When there is no air source, the screw rod and the opening and closing nut can be used to open and close the valve. First, the upper and lower intake pipes of the cylinder are in the exhaust state, and the small handle of the manual part is in the manual position, so that the opening and closing nut and the screw are in the manual position. In the normal meshing state, turn the large handwheel at the manual part at this time. When the handwheel is turned clockwise, the valve is closed, and when the handwheel is turned counterclockwise, the valve is opened. When the air source is introduced from the upper air inlet, the valve stem drives the valve plate to move downward, and the valve is closed.
When the air source is introduced from the lower air inlet, the valve stem drives the valve plate to move upward, and the valve opens.
Pneumatic gate valve parameters:
Actuator: cylinder piston structure;
Optional accessories: manual device, filter, solenoid valve, echo device, control box;
Main material: ductile iron, cast steel, stainless steel; Caliber: DN50-500;
Pressure: PN1.6-6.4mpa;
Temperature: Q-29~350℃, C-29~450℃, P-30~540℃;
Medium range: water, steam, petroleum, gas, fluid, medium containing hard particles and impurities.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6

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