gate valve manufacturer Archives

What are the advantages of gate valves-resilient & metal seated

April 15, 2022

The gate valve has an opening and closing gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

valve is sealed by the contact between the valve seat and the gate plate. Usually, the sealing surface will be surfacing with metal materials to increase wear resistance, such as surfacing 1Cr13, STL6, stainless steel, etc. The gate has a rigid gate and an elastic gate. According to the different gates, the gate valve is divided into a rigid gate valve and an elastic gate valve.
Gate valve is a kind of valve with a large number of consultations every day. It is often used in water supply systems. The advantages of gate valves are:
1. Small flow resistance. The medium channel inside the valve body is straight, and the medium flows in a straight line. When the gate is fully opened, the internal resistance of the valve body channel is almost zero, and the flow resistance is very small.
2, opening and closing labor-saving. Whether the gate valve is open or closed, the movement direction of the gate is perpendicular to the flow direction of the medium, and the resistance of the gate to the lifting movement is also very small, and it is very labor-saving to open and close.
3. The full opening and full closing of the gate valve requires a long stroke, and the closing time is relatively long, which also makes the water hammer phenomenon less likely to occur.
4. The two sides of the gate valve channel are symmetrical, and the installation is not restricted by the flow direction of the medium, which is convenient for installation.
5. The shape is simple, the length of the structure is short, the manufacturing process is good, and the scope of application is wide.
6. Wide range of uses, gate valves are made of gray cast iron, ductile iron, cast steel, stainless steel, forged steel and other materials. Different materials can be used in different working conditions and environments, and have a wide range of applications.
Precautions for installation and use of gate valve
1. The handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.
2. The double gate gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is at the top).
3. The gate valve with bypass valve should open the bypass valve before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).
4. The gate valve with transmission mechanism shall be installed according to the provisions of the product instruction manual.
5. If the valve is frequently switched on and off, lubricate it at least once a month.
6. The gate valve is only used to fully open and fully close the medium on various pipelines or equipment, and is not allowed to be used for throttling.
7. For gate valves with handwheels or handles, auxiliary levers should not be added during operation (if the sealing is not tight, the sealing surface or other parts should be checked and repaired). Turn the handwheel and handle clockwise to close, and vice versa. The gate valve with transmission mechanism should be used in accordance with the stipulations in the product instruction manual.

gate valve (3)

The difference between a metal seated gate valve and a resilient seated gate valve:

What are the differences between hard sealing gate valves and soft sealing gate valves? This article will introduce you.

material difference:
The material of the hard sealing gate valve body is mainly cast steel, stainless steel and forged steel. The gate plate and internal flow channel seal are all made of Stellite alloy accumulation welding.
The material of the soft-sealed gate valve body is mostly cast iron, the valve plate is covered with rubber, the appearance of the soft-sealed gate valve, and the valve wall of the flow channel side are all sprayed with electrostatic powder. Not only is the appearance beautiful, but more importantly, the smoothness of the flow channel and the inner valve wall ensures that the rubber-lined gate will not be affected by the roughness of the inner valve wall when opening and closing.

difference in use:
Soft-sealed gate valve is suitable for non-corrosive gas-liquid medium at normal temperature (≤80℃). Such as water, air, oil, water treatment sewage and other pipelines. And has a good sealing effect, almost zero leakage can be achieved.
The hard-sealed gate valve is suitable for high temperature (≤425℃) with slightly corrosive gas and liquid. Such as steam, heat transfer oil, sewage, petroleum, chemical industry, metallurgy, pipeline. Can have a certain degree of wear resistance.

To sum up, the difference between a soft-sealed gate valve and a hard-sealed gate valve is that the sealing performance of the soft-sealed gate valve is better than that of the hard-sealed gate valve, but the temperature and wear resistance of the hard-sealed gate valve is better than that of the soft-sealed gate valve. Each has advantages and disadvantages.

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

Video of resilient seated gate valve:

How many types of gate valves? gate valve classification

January 6, 2022

How many kinds of gate valves are there? Which gate valve is suitable for which occasion? How many kinds of gate valves are there?

Commonly used gate valves are as follows:

DIN-F4-BB-NRS-soft seated-wedge gate valve-DN100-PN16-copper holding ring-handwheel (3)

1. Gray iron gate valve: including gray iron open rod gate valve and gray iron dark rod gate valve, this gate valve is suitable for municipal construction, water treatment, water supply and drainage, water conservancy engineering and other fields.

2 ductile iron gate valve: usually for soft seal gate valve, and divided into exposed rod and hidden rod. This kind of gate valve is mainly used in sewage treatment, building fire control, water supply and drainage engineering and other municipal engineering pipeline.

Gray cast iron gate valves and ball valve gate valves are cast iron gate valves. These gate valves are mostly used in normal temperature and low pressure pipelines, and the medium used is mostly water.

3 carbon steel gate valve and stainless steel gate valve: these two kinds of gate valves are used in high temperature and high pressure pipelines, the use of medium for steam, oil and so on. Applications include petroleum, chemical, metallurgy and so on.

4. Knife gate valve: suitable for all kinds of fluid media such as pulp, mud, sewage, powder, syrup, coal pulp, ash, slag-water mixture, etc.

Knife gate valve (6)

The above are just a few common gate valves. In fact, gate valves are not only the above, according to the structure of gate valves, different standards, connection, drive, etc., can be divided into many types.

According to the structure:

1. Implicit stem gate valve: stem nut is placed inside the valve body, in direct contact with the medium, often fixed on the gate. Through the rotation of the stem, the stem nut drives the lubrication plate up and down to complete the opening and closing.

2. Plain stem gate valve: the stem trapezoidal thread is placed outside the valve body, on the upper part of the stem. By rotating stem nut, stem drives gate synchronous rise and fall, realize valve opening and closing, easy to identify the valve. On and off state to avoid misoperation.

3. Flat gate valve: the sealing face is parallel to the vertical center line, so the valve body is parallel to the sealing face on the gate. This valve is the most common type of double gate.

4. Wedge valve: the sealing face is at a certain Angle with the vertical center line, that is, the two sealing faces are wedge valves.

According to different standards: gb gate valve, American standard gate valve, German standard gate valve, Japanese standard gate valve.

According to the connection mode: flange gate valve, welding gate valve, threaded gate valve.

According to the pressure grade: high pressure gate valve, medium pressure gate valve, low pressure gate valve.

According to the driving mode: electric gate valve, pneumatic gate valve, manual gate valve.

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

Video of knife gate valve:

Video of resilient seated gate valve:

Can cast steel gate valves and 304 stainless steel gate valves be universal?

October 27, 2021

Commonly used cast steel gate valves and 304 stainless steel gate valves are made of steel, and some customers think that stainless steel gate valves are more expensive than cast steel. Can they be universal if they have similar

electric stainless steel gate valve

performance. This is not possible. The two valves cannot be used universally, because the media they are applicable to are still different.
Stainless steel gate valve is more corrosion-resistant and durable! It can still easily hold media with high acid and alkali content, and can be applied to special media. Cast steel gate valves will not work. They are not resistant to acid and alkali. If they are in a medium with high acid and alkali content, they will rust after a while, and they will rust after a while. Cast steel gate valves are more suitable for common media, such as power plants.
Regarding the fact that stainless steel gate valves are more expensive than cast steel gate valves, it also requires specific analysis and cannot be summarized simply. For example, if you use high-density high-quality cast steel gate valves to compare with regular 304 stainless steel gate valves, the cast steel gate valves are more expensive. If it is a lower quality cast steel gate valve compared with a regular 304 stainless steel gate valve, then the stainless steel gate valve is expensive. So we still have to choose according to our own working conditions and make a good budget.

PN40-DN100 cast steel WCB gate valve photo

The types of stainless steel gate valves can be divided into wedge gate valves and parallel gate valves according to the sealing surface configuration. Wedge gate valves can be divided into: single gate, double gate and elastic gate; parallel gate gate valves It can be divided into single gate type and double gate type. Divided according to the thread position of the valve stem, it can be divided into two types: open stem gate valve and dark stem gate valve. This type of valve should generally be installed horizontally in the pipeline.
To find a good gate valve product, first of all, a good manufacturer is very important. Tanghai Valve has focused on the production of gate valves for 24 years, with rich experience and good feedback from product users. It is your intimate valve procurement expert. You are welcome to visit the factory!

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

What are the connection methods of gate valves for hydropower stations

September 29, 2021

Gate valves used in hydropower stations are often in a relatively special working environment, which also puts forward high requirements on the quality of the gate valves. Among them, the connection method it uses is also an important process composition. What we are going to share today is about the connection method of gate valves for hydropower stations.

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

The most common connection method used in gate valves of hydropower stations is mainly flange connection. This connection method is usually two flange pieces plus a number of fastening bolts and nuts, and the pipes are connected by pressing the middle flange gasket. Why do you think that flange connection is the most suitable method for gate valves in hydropower stations? This is mainly because the flange connection can withstand high-strength tensile, compression, torsion and shear resistance. The flange connection is a detachable joint, which has the advantages of convenient disassembly, high connection strength, and good tightness.
According to the shape of the joint surface, the flange connection can be divided into: smooth type, used for gate valves with low pressure; concave-convex type; tongue and groove type: widely used in corrosive media, with better sealing effect; trapezoidal groove type: Use an oval metal ring as a washer, which is used for gate valves with a working pressure of ≥64 kg/cm², or high-temperature gate valves; lens type: the washer is in the shape of a lens and is made of metal. Used for high-pressure gate valves or high-temperature gate valves with working pressure ≥100 kg/cm²; O-ring type: This is a newer form of flange connection, which is developed with the appearance of various rubber O-rings As a result, it is more reliable than ordinary flat gaskets in terms of sealing effect. In addition to flange connection, there is also threaded connection or ferrule connection, which is a simple connection method that can reliably prevent leakage and so on.
After a brief introduction, do you have your own ideas for the selection of gate valves for hydropower stations? If you need a gate valve for a hydropower station, please first consider Tanghai Valve. The gate valve produced by Tanghai Valve is mainly used in normal temperature and pressure environment, professional and high-quality, and professional technicians will give reasonable suggestions according to your working conditions, so that you can easily choose the right one. Of valve products, you are welcome to contact us at any time.

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

Design Features of Electric Gate Valve

September 9, 2021

An electric gate valve is a gate valve that uses an electric actuator to control the opening and closing of the valve. Its structure can be divided into upper and lower parts, the upper part is the electric actuator, and the lower part is the gate valve body. Connect the electric actuator and the gate valve, after installation and debugging, it becomes an electric gate valve. The electric gate valve uses electric energy to realize the opening and closing of the valve, so as to control the interception and circulation of the pipeline medium.

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

The switching speed of the electric gate valve can be adjusted, the structure is relatively simple, and the maintenance is easier. Its design structure also has its own characteristics.
1. The electric gate valve adopts pressure self-tightening seal, which has excellent sealing performance and is reliable and safe to use.
2. The electric gate valve adopts a double gate with a universal roof structure in the middle, which can automatically adjust the degree of sealing between the gate and the valve seat to ensure the sealing performance of the valve. At the same time, this structure is very convenient to maintain and save costs.
3. The sealing surface of the gate and the valve seat is made of cobalt-chromium-tungsten cemented carbide by plasma spray welding. The sealing surface has high hardness, and is very wear-resistant and corrosion-resistant, which prolongs the service life of the valve.
4. The valve stem is made of nitrided steel, and the surface is nitrided, which has high hardness, good performance and long life.
5. The electric device of the electric gate valve is equipped with a torque control mechanism, an on-site operating mechanism and a hand and electric switching mechanism. It can also carry out remote operation and intelligent control. It is suitable for use in situations where manual operation is difficult or the pipeline environment is complex and dangerous.
6. When the electric gate valve is used for the first time, during installation and debugging, it is necessary to manually open the valve to about half of the position, so as to avoid the valve or electrical equipment damage due to the reverse connection of the motor phase sequence.

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

Precautions for installation and use of NRS gate valve

August 26, 2021

NRS gate valve means non-rising stem gate valve; RS gate valve means rising stem gate valve.

Gate valves can be divided into RS gate valves and NRS gate valves according to their appearance structure. This article mainly introduces the NRS gate valve. In the structure of the NRS gate valve, the stem nut is placed inside the valve body and fixed on the gate plate. Through the rotation of the valve stem, the valve stem nut drives the gate plate to move up and down to complete the opening and closing.

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

The trapezoidal thread used in the drive of the concealed stem gate valve is located inside the valve body, so it is not affected by the external environment, but it is easily corroded by the medium circulating in the pipeline, and cannot be directly lubricated, which will damage the valve stem over time. Because the valve stem is located in the valve body, the opening degree of the concealed stem gate valve cannot be directly observed, and an indicator device is required.
The concealed stem gate valve requires a small operating space and is suitable for occasions with limited locations and dense pipelines, such as ships and underground pipelines. So what should be paid attention to during the installation and use of the concealed stem gate valve?
1. Before installation, you must carefully check the various standards of the concealed stem gate valve and whether the diameter meets the requirements for use; pay attention to the valve during transportation to avoid bumps. Before installing the concealed stem gate valve, remove the dirt in the valve body.
2. During installation, the concealed stem gate valve can be directly installed on the pipeline according to the connection method and installed according to the used position. Under normal circumstances, it can be installed at any position of the pipeline, but for future operation and maintenance considerations, choose an appropriate location for installation. The concealed stem gate valve should pay attention to the tightness during installation to prevent leakage and affect the normal operation of the pipeline.
3. The NRS gate valve should always be kept clean during use, and the transmission thread must be regularly lubricated. When a fault is found, it should be stopped immediately to find out the cause and clear the fault.
4. The concealed stem gate valve uses a hand wheel, do not use levers or other tools to avoid damaging the valve parts. Turn the handwheel clockwise to close, and vice versa to open. The dark stem gate valve should be used reasonably to ensure the correct use method and means.
5. The NRS gate valve stored for a long time should be checked regularly. The processing surface that is often

DIN-F4-BB-NRS-soft seated-wedge gate valve-DN100-PN16-copper holding ring-handwheel (3)

exposed should be kept clean, cleaned of dirt, and stored neatly in a ventilated and dry place indoors. It is strictly forbidden to stack or store in the open air.

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

Pneumatic gate valve model preparation method

July 28, 2021

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

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)

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 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

How many types of gate valves?

July 19, 2021

Types and classifications method of gate valves
Gate valve, also called slab valve, is mainly composed of valve body, bonnet, gate, valve stem, valve seat and sealing packing. It is one of the most common valve types in isolation valves. The main purpose of the gate valve is to cut off the fluid. For this reason, it is usually called a “cut off” valve or a “blocking” valve. There are many different structural forms of gate valves, and the types of sealing elements used in them are different. According to the

Socket ended resilient seated wedge gate valve-ductile iron (1)

structure of the sealing element, it can be divided into several different types.
Classified by valve stem:
According to the stem type, it can be divided into bright stem gate valve and dark stem gate valve. The valve stem is the operating part of the gate valve, and its function is to transmit the opening and closing force to the opening and closing parts.
1. The trapezoidal thread of the stem of the rising stem gate valve is placed outside the valve body and located on the upper part of the valve stem. By rotating the stem nut, the valve stem drives the gate plate to rise and fall synchronously to realize the opening and closing of the valve, so it is easy to identify the valve. Open and close state to avoid misoperation. Since the stem nut is outside the body cavity, it is conducive to lubrication, and the opening and closing state is intuitive and obvious, so it is widely used. However, in harsh environments, the exposed threads of the valve stem are susceptible to damage and corrosion, even affecting operation. Its disadvantage is that the height of the valve after opening is large, and a stroke is usually added to the original height of the valve, which requires a lot of operating space.
2. Dark stem gate valve is also called rotating stem gate valve (also called dark stem wedge gate valve). The stem nut is placed inside the valve body and is in direct contact with the medium. It is often fixed on the gate. Through the rotation of the valve stem, the valve stem nut drives the gate to move up and down to complete the opening and closing. Usually there is a trapezoidal thread at the bottom end of the valve stem. Through the thread at the bottom end of the valve and the guide groove on the valve disc, the rotary motion is changed into linear motion, that is, the operating torque is turned into operating thrust. Since the trapezoidal thread used for transmission is located inside the valve body, it is easily corroded by the medium and cannot be lubricated. The opening degree cannot be directly observed, and an indicating device is required. However, its valve stem does not move up and down, and requires a small operating space, so it is suitable for occasions with limited locations and dense pipelines.

gate valve (3)

Classified by structure:
According to the structure type, it can be divided into two types: wedge gate valve and parallel gate valve. That is, a wedge-type gate valve is called a wedge gate valve, and a parallel gate valve is a flat gate valve.
1. The flat gate valve means that the sealing surface is parallel to the vertical centerline, so the sealing surface of the valve body and the gate plate are also parallel to each other. The most common type of this kind of gate valve is the double gate type. In order to make the valve body and the two sealing surfaces of the gate closely contact when closed, a double-sided thrust wedge is often used between the two gates. Most of them are used on low-pressure pipelines such as small pipelines. Parallel gate valves using single gates are also rare but rare.
2. Wedge gate valve means that the sealing surface is at a certain angle to the vertical centerline, that is, the two sealing surfaces are wedge-shaped gate valves. The wedge gate valve has single and double gate plates. The advantage of the double gate type is that the accuracy of the sealing and the angle is lower, the temperature change is not easy to make the gate wedged, and the sealing surface wear can be compensated with gaskets. The disadvantage is that the structure is complex, and it is easy to stick in dry media, and the main reason is that the upper and lower baffles are easy to fall off after years of corrosion.
Classification by other methods:
According to different standards: national standard gate valve, American standard gate valve, German standard gate valve, Japanese standard gate valve
According to the connection method: flanged gate valve, welded gate valve, threaded gate valve (divided into internal thread and external thread)
According to pressure level: high pressure gate valve, low (medium) pressure gate valve According to driving mode: electric gate valve, pneumatic gate valve, manual gate valve
Classified by material: stainless steel gate valve, forged steel gate valve, cast steel gate valve, carbon steel gate valve, cast iron gate valve, copper gate valve (also divided into bronze gate valve, brass gate valve), ceramic gate valve, plastic gate valve

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

The structure and characteristics of bellows gate valve

June 24, 2021

The structure and characteristics of bellows gate valve
The valve stem of the bellows gate valve adopts a double sealing structure of bellows and packing to ensure a leak-free seal at the valve stem. It is used in power stations, natural gas, ammonia, vacuum, refrigeration systems, hot oil, and hot water systems. It is especially suitable for flammable, Pipelines for explosive, toxic and precious media.

rising stem gate valve-OS&Y (3)

Bellows gate valve structure:
The bellows, bonnet and stem of the bellows gate valve are welded into one body without seams, so there is no leakage. The action of the valve stem is caused by the deformation of the compressed bellows, not by relative movement. Ordinary gate valves are sealed with packing, the valve stem and packing will slide, and it is easy to leak (spool) at low temperatures. Bellows gate valves do not have this problem.
Structure diagram of bellows gate valve
Bellows gate valves use stainless steel hermetic bellows that can be stretched and compressed instead of packing seals. They are generally used for the transmission of more permeable media, such as valves on hydrogen systems. As long as the bellows are not damaged, there is generally no leakage; while general gate valves Packing is used for sealing, which is prone to leakage.
Features of bellows gate valve:
1: The corrugated gate valve is double-sealed, bellows (stainless steel) + packing, and has better safety performance, so it is often used in systems such as toxic media, flammable and explosive media, high-temperature steam, and hot oil.
2: The switching torque is small, the switching is relatively easy, there is no flow resistance loss, the service life is long, and the appearance is beautiful. Related knowledge: Working principle of gate valves Types and classifications of gate valves

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
related news /knowledge: Comparison of bellows globe valve and ordinary globe valve; Fasteners, fillers and gasket materials of valves;

Gate valve characteristics and installation notes

August 13, 2020

Gate valve characteristics:
Light weight
The body is made of high-grade nodular cast iron, the weight is about 20%~30% less than the weight of traditional

13 gate-valve-5

gate valve, and the installation and maintenance are convenient.

Flat bottom brake seat:
Traditional gate valves often silt in the grooves at the bottom of the valve due to foreign objects such as stones, wood, cement, iron filings, sundries, etc., after the pipe is washed with water, which can easily cause water leakage. The bottom of the gate valve is sealed by elastic seating. It adopts the same flat-bottom design as the water pipe machine, which is not easy to cause debris accumulation and makes the fluid flow unimpeded.

Overall encapsulation:
The gate adopts high-quality rubber for the overall inner and outer rubber. European rubber vulcanization technology enables the vulcanized gate to ensure accurate geometric dimensions, and the rubber and ductile cast gate are firmly connected, not easy to fall off and have good elastic memory.

Precision casting valve body:
The valve body is made of precision casting, and the precise geometric dimensions make the inside of the valve body without any finishing to ensure the sealing of the valve.

Installation Precautions of gate valve:
1. Handwheels, handles and transmission mechanisms are not allowed to be used for lifting, and collisions are strictly prohibited.

2. The double gate valve should be installed vertically (that is, the valve stem is in the vertical position and the handwheel is on the top).

3. The gate valve with a bypass valve should be opened before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).

4. The gate valve with transmission mechanism should be installed according to the product manual.

5. If the valve is frequently opened and closed, lubricate at least once a month.

6. The gate valve is only used for the operation of the medium on various pipelines or equipment, which is fully open and fully closed, and is not allowed to be used for throttling.

7. For gate valves with hand wheels or handles, no auxiliary levers should be added during operation (if the sealing is not tight, the sealing surface or other parts should be checked and repaired). Turn the handwheel and handle clockwise to close, otherwise open. The gate valve with transmission mechanism should be used in accordance with the product manual.

Installation points of gate valve:

1) The installation position, height, and direction of inlet and outlet must meet the design requirements, and the connection should be firm and tight.

2) All kinds of manual valves installed on the thermal insulation pipeline must not handle downwards.

3) Visual inspection must be carried out before the valve is installed. The nameplate of the valve should comply with the current national standard “General Valve Marking” GB 12220. For valves with a working pressure greater than 1.0 MPa and a cut-off function on the main pipe, the strength and tightness performance test should be carried out before installation, and the valve can be used only after it is qualified. During the strength test, the test pressure is 1.5 times the nominal pressure, and the duration is not less than 5 min. The valve housing and packing should be qualified without leakage. During the tightness test, the test pressure is 1.1 times the nominal pressure; the test pressure should meet the requirements of the GB 50243 standard during the test duration, and no leakage on the valve flap sealing surface is qualified.

4) The hand wheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.

5) The gate valve with transmission mechanism should be installed according to the product manual.

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

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