soft seal gate valve Archives

Can a gate valve be used for oxygen as the medium?

November 3, 2021

If the soft-sealed gate valve you purchase will be used for oxygen media, the manufacturer will usually advise you not to do so, and inform you that it is prohibited to use gate valves in oxygen media pipelines in the specification. What

Grooved resilient seated BB NRS wedge gate valve (4)

is the reason for this requirement? In fact, this is mainly related to the movement of the gate valve. The opening and closing method of the gate valve is the vertical movement of the gate. The gate and the valve seat will have strong friction and sparks may be generated. Since the contact between the valve plate and the valve seat is not continuous, it is also Static electricity may occur, which is very dangerous when used in flammable and explosive oxygen media pipelines. Let’s analyze it in detail below.

According to the characteristics of the gate valve: the gate valve should not be used to adjust the flow and pressure, otherwise, the sealing surface will wear out quickly and the tightness will decrease.

Moreover, the gate valve cannot be slowly opened for pressure adjustment, so the gate valve is not suitable for oxygen pipelines. One of the reasons why gate valves are forbidden in peroxygen pipelines is that the sealing surface of the gate valve will fall off from the sealing surface due to friction due to relative movement. Although this seems so trivial to us in normal times, in an environment of high-pressure pure oxygen, these small particles of iron powder are very easy to reach the ignition point and burn, and bury potential safety hazards.

Here, there is one more thing to pay attention to, that is, the safety hazards of the oxygen pipeline are not all to blame on the gate valve. When the pressure difference between the two sides of the valve is large, an explosion accident will also occur. Judging from the lessons learned from the accident, banning the gate valve is actually prohibiting the production of combustibles, and the purpose is the same as the regular removal of rust, degreasing, and banning oil. The need to further control the flow rate, do a good job of static grounding and other measures to eliminate the source of ignition, it has a great relationship with the valve material. Although copper-based alloy gate valves are more effective than cast iron and cast steel gate valves in preventing the production of combustibles, this does not mean that there are no hidden safety hazards. The reason is that there is no control of the fire source, and it is impossible to focus on the safety of the gate valve without controlling the source. The attention to operating pressure and the meticulous maintenance of the entire pipeline at all stages must tighten the nerve of safety, not just considering whether a gate valve is used.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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

Characteristics of soft seal /resilient seated gate valves

September 7, 2021

Title: what are the characteristics of soft seal /resilient seated gate valves?

Traditional gate valves often have water leakage and corrosion. In order to overcome this shortcoming, the soft-seal gate valve appeared. As an updated product of the traditional gate valve, the soft-seal gate valve overcomes the shortcomings of poor sealing performance, poor elasticity, and easy corrosion of general gate valves.
The soft-seal gate valve uses a flexible rubber-wrapped gate, which uses the elastic energy of rubber to produce a small amount of deformation compensation, so that the valve can achieve a good sealing effect. The characteristics of the soft seal gate valve are as follows:

DIN-F5-BB-NRS-soft seated-wedge gate valve (10)

1. The gate is made of integral rubber
Use high-quality rubber to tightly wrap the gate of the soft-seal gate valve as a whole, which improves the sealing performance and is not easy to fall off.
2. The valve body is not easy to rust and corrosion resistant
The use of powder epoxy resin to coat the valve body of the soft-seal gate valve can effectively prevent the valve body from being oxidized, not easy to rust, and also prevent the valve body from being corroded. Soft-seal gate valves are often used in sewage treatment systems.
3. The valve seat is designed with a flat bottom
Traditional gate valves usually have a groove at the bottom of the valve seat. When the medium in the pipeline flows through the valve, impurities and particles contained in the medium will settle and silt in the bottom groove, which will make the valve unable to close tightly and cause leakage. Cause an accident. The bottom of the valve seat of the soft sealing gate valve is designed with a flat bottom and has no groove. After the medium in the pipeline flows through, there will be no siltation of impurities and particles, and the sealing performance of the valve is guaranteed to avoid leakage.
4. Precision casting valve body
The valve body of the soft sealing gate valve adopts precision casting, the size is accurate, and the inside of the valve body does not need to do any fine processing, and the sealing performance of the valve body is guaranteed.
5. Ductile iron valve body, light weight
The soft seal gate valve uses ductile iron as the valve body material. The overall weight of the valve is 20%-30% lighter than the traditional gate valve. The lighter weight makes the soft seal gate valve easier to install and maintain.
6. The inside of the valve body is not easy to be corroded
The valve body of the soft sealing gate valve is coated with non-toxic epoxy resin, and the gate is completely wrapped by rubber, which can effectively prevent the inside of the valve body from being corroded by the medium in the pipeline.
7. Three “O” seal ring seal design
The valve stem of the triple “O” seal ring seal design greatly reduces the friction resistance of the soft seal gate valve when it is closed, and the sealing performance is reliable, and no water leakage occurs; the unique design structure also makes the “O” seal ring It can be replaced under pressure and is maintenance-free.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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

Difference between Soft seal gate valve and hard seal gate valve

July 28, 2020

Soft seal gate valve and hard seal gate valve are two major categories in the gate valve series. Hard seal and soft seal can sometimes compensate for each other, and

13 gate-valve-5

sometimes they are independent of each other. So what is the relationship between soft seal gate valve and hard seal gate valve? What are the main differences? Next, the editor of Tanghai Valve will solve these mysteries for everyone.

1. Sealing material

Soft seal gate valve: the seal pair is made of metal materials on one side and elastic non-metallic materials on the other side, which is called “soft seal”. This kind of seal has good sealing performance, but it is not resistant to high temperature, easy to wear, and has poor mechanical properties.

Hard seal gate valve: The two sides of the seal pair are made of metal materials or other harder materials are called “hard seals”. This kind of seal has poor sealing performance, but has high temperature resistance, abrasion resistance and good mechanical properties.

2. Structure mechanism

The hard seal gate valve is a seal between metal and metal, and the sealing ball and valve seat are both metal. Machining accuracy and craftsmanship are more difficult, and are generally used in high pressure, usually above 35MPa. The soft seal gate valve is a seal between metal and non-metal, such as nylon\tetrafluoroethylene, and the manufacturing standards are the same.

3. Equipment selection

The selection of soft and hard seal gate valves is mainly based on the process medium, temperature and pressure. Generally, the medium contains solid particles or wears or the temperature is higher than 200 degrees. It is best to use hard seals. Valves with a diameter greater than 50 have a larger pressure difference and consider opening the valve torque. , When the torque is large, the fixed hard-seal ball valve should be selected, and its sealing level can reach 6 regardless of the soft or hard seal.

3. Conditions of use

The soft seal gate valve generally has a very high seal, while the hard seal can be high or low according to the requirements; the soft seal needs to be fireproof, because the material of the soft seal will leak at high temperatures, while the hard seal does not have this problem; Seals can generally be made at very high pressures, but soft seals cannot; soft seals cannot be used in some situations due to the problem of the flowing medium. Finally, hard seal valves are generally more expensive than soft seals. As for manufacturing, there is little difference between the two, mainly the difference between the valve seat, the soft seal is non-metallic, and the hard seal is metallic.

Through the above introduction, I believe everyone can understand the difference between soft seal gate valve and hard seal gate valve. With the continuous development of China’s industrial market, it is necessary to understand the difference between soft seal gate valve and hard seal gate valve, which may not only affect Production efficiency may also greatly affect economic efficiency

Posts

Can a gate valve be used for oxygen as the medium?

Characteristics of soft seal /resilient seated gate valves

Difference between Soft seal gate valve and hard seal gate valve

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