gate valve Archives

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

What are the taboos when installing valves

August 25, 2021

The valve is an important component in the fluid pipeline, and it is also a relatively fragile pipeline control device. Installing a valve is a technical task. It seems easy. In fact, there are many details to pay attention to. If there are some contraindications when installing the valve, it is serious. It will cause immeasurable consequences. This article will explain this problem to help you install valves safely and produce safely.

manual valve installation site-method

Taboos during valve installation
1. During winter construction, the valve shall be hydrostatically tested in a sub-zero temperature environment.
Possible consequences: due to the rapid freezing in the tube during the hydraulic test, the tube freezes.
The correct method: try to do a hydraulic test on the valve before the winter as soon as possible. After the pressure test, the water inside and outside the valve must be cleaned to prevent the valve from freezing and cracking in winter. If it is necessary to do a water pressure test in winter, it needs to be carried out indoors at a temperature above zero. Similarly, the water must be removed after the pressure test.

2. The sewage, rainwater, and condensate pipes for concealed installation are not subject to closed-water tests.
Possible consequences: Once there is a problem with the pipeline, it can not be found in time, and there will be water leakage, which will cause losses to the user.
The correct method: For concealed sewage, rainwater, condensate pipes, etc., closed water tests must be performed in strict accordance with the specifications to ensure that there is no leakage.

3. The flange of the butterfly valve can be replaced by the flange of the ordinary valve at will.
Possible consequences: Because the size of the flange of the butterfly valve is different from that of the ordinary valve, the disc of the butterfly valve is relatively large. If the inner diameter of the flange is too small, it will affect the opening and closing of the butterfly valve and cannot open normally , And eventually damage the valve. Measures: Correct method: Process and install the flange according to the actual size of the butterfly valve flange.

4. The valve installation method is wrong, for example, the installation direction is wrong, and the installation is not carried out in the direction indicated by the valve instruction.
Possible consequences: valve operation failure, difficult opening and closing, troublesome maintenance, leakage of valve body seal.
Correct method: When installing the valve, install it in strict accordance with the valve installation manual. After the installation is completed, check it against the manual.

5. The installed valves, specifications and models do not meet the design requirements.
Possible consequences: affect the normal use of the valve, or even damage the valve and cause losses.
The correct method: Before installing the valve, you must fully understand the working conditions and environment of the construction, and at the same time, you must be familiar with the application range of various valves, and select the valve model and specifications in strict accordance with the requirements of the working conditions.

6. Before installing the valve, the quality inspection of the valve was not carried out in accordance with the regulations.
Possible consequences: Failure to conduct quality inspection on valves, resulting in unqualified valves being installed on pipelines, increasing the possibility of pipeline leakage, and also increasing potential safety hazards in production.
Correct method: Before the valve is installed, the valve must be strictly inspected. The test should be 10% of the total number of valve products in each batch to ensure that the valve meets various national standards.

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

Introduction to basic knowledge of gate valve

August 16, 2021

The gate valve is one of the important pipe fittings in the pipeline for conveying fluid media. The gate valve is mainly used for cutting off the medium. It can only be fully opened or fully opened, and cannot be used for flow adjustment. Its opening and closing part is a gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate has two sealing surfaces. When the gate valve is closed, the sealing surface of the gate can be pressed to the other side only by the pressure of the medium. The valve seat is sealed, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, it needs to rely on the external force of the medium to force the gate to the valve seat to ensure the tightness of the sealing surface.

BS5163-BB-NRS-soft seated-wedge gate valve-DN200-PN16-handwheel (1)nt

The gate valve has a wide range of uses, and has applications in petroleum, petrochemical, chemical, metallurgical, electric power, water conservancy, urban construction, fire protection, coal and other industries. Gate valve is also a valve with distinct advantages and disadvantages.

Advantages of gate valve
1. After the gate valve is opened, the medium channel inside the valve body is straight, without any obstruction, and the flow resistance is very small.
2. When opening and closing, the movement direction of the gate valve is perpendicular to the flow direction of the medium, the pressure is small, and the opening and closing is labor-saving.
3. The height of the gate valve is large, so the opening and closing time is longer, and water hammer is not easy to occur.
4. The two sides of the gate valve channel are symmetrical, and the medium can flow in any direction on both sides, so the installation of the gate valve is very convenient.
5. The length of the structure is short, the manufacturing process is good, and the scope of application is wide.

Disadvantages of gate valve
1. The sealing surface of the gate valve is very easy to wear, which affects the service life of the valve, and it is troublesome to maintain.
2. The structure of the gate valve is more complicated, and it is also troublesome to process, especially the sealing surface on the gate seat is not easy to process, and there are many parts, so the price is more expensive.
3. The overall size is large, a certain amount of space is required for opening, and the opening and closing time is long.

Precautions for installation and use 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 sluice gate valve should be installed vertically, that is, with the hand wheel facing upwards.
3. The gate valve with bypass valve should be opened before opening, the purpose is to balance the pressure difference between the inlet and outlet.
4. The gate valve with transmission mechanism should be installed strictly in accordance with the product manual.
5. If the gate valve is switched frequently, lubricate at least once a month.
6. The gate valve is not suitable for regulating or throttling.

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 NRS gate valve and RS gate valve

August 11, 2021

NRS gate valve, means Non-rising Stem gate valve; RS gate valve, means Rising stem gate valve. you can see the difference in appearance on below photos.

Gate valve is one of the most common valves in piping systems. Because it can only be fully open and fully open, gate valves are commonly used when the fluid medium in the pipeline needs to be cut off. The operation of the gate valve does not need to be so frequent. Gate valves are widely used because they can be divided into many types. Different gate valve types have certain differences in use. This article mainly analyzes the difference between the RS gate valve and the NRS gate valve.

rising stem gate valve-RS-BB OS&Y (3)

Gate valves are classified according to the type of stem, which can be divided into two types: RS gate valve and NRS gate valve. The two are different in transmission mode, valve body structure, installation space, application range, etc.
1. The difference in the transmission mode. The transmission mode of the RS gate valve is that the handwheel drives the nut to rotate in place, and the valve stem rises and falls linearly. Through the threaded drive of the valve stem and the steering wheel, the valve flap is raised and lowered to complete the switch; the NRS gate valve is manual The wheel drives the valve stem to rotate. The hand wheel and the valve stem are connected together and relatively immovable. There are threads in the gate, and the valve stem rotates at a fixed point to drive the gate to rise and fall.
Second, the difference in structure, the structure of the rising stem gate valve is that the stem nut is on the bonnet or bracket. When the gate is opened and closed, the stem nut is rotated to realize the lifting of the stem. The structure of the NRS gate valve is that the stem nut is in the valve body and is in direct contact with the medium; when opening and closing the gate, it is realized by rotating the stem.

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

Third, the difference in installation space, the rising stem gate valve requires a larger installation space due to the stem; the height of the NRS gate valve is small, and it will not take up too much space during installation.
Fourth, the difference in application scope, the structure of the rising stem gate valve is beneficial to the lubrication of the stem, and the degree of opening and closing is obvious; the stem thread of the NRS stem gate valve is not only unable to be lubricated, but it is directly corroded by the medium and is easily damaged. Therefore, the RS gate valve is more The NRS stem gate valve has a wider range of applications.

The above is the difference between the RS gate valve and the NRS gate valve. Next, I will introduce you a little common sense, how to judge the RS gate valve and the NRS gate valve:

The stem of the RS gate valve drives the gate to move up and down together. The drive thread on the stem is outside the valve body. The opening and closing and position of the gate can be intuitively judged according to the movement direction and position of the stem; the drive thread of the NRS gate valve is located on the valve. Inside the body, during the opening and closing process, the valve stem only rotates, the gate moves up and down in the valve body, and the valve opens and closes until the steering wheel does not rotate.

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

Ways to Extend the Service Life of Valves

August 10, 2021

In industrial production, we always want to reduce costs, increase production capacity, and maximize profits. In addition to vigorously developing scientific and technological productivity, in daily work, paying attention to some small details, avoiding waste, can also reduce costs. Valves are disposable items and have their own service life. Once this period has passed, they must be replaced with new ones. Frequent replacement of valves will increase our production costs. Therefore, extending the service life of the valve can also maximize our production benefits. This article will start with the selection of the valve and tell us how to maximize the service life of the valve during the process of valve maintenance.

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

Valve selection
Getting the best performance level of the valve is the first step in ensuring the life of the valve, so we have to make sure that the right valve is selected and used in the right place. In many cases, the main reason for valve leakage and failure is the wrong valve design or the wrong material of construction. Therefore, when selecting a valve, you must be clear about the parameters of the pipelined medium, use temperature, pressure, etc., and select the correct and appropriate valve according to the parameters.

Valve installation
After purchasing a suitable valve, pay special attention to the installation. On-site technicians may cause further damage to the valve when removing the valve end cover. When the end cover is removed, dust and foreign matter will be deposited in the valve, which may cause Damage to the ball and valve seat, and cause leakage once installed. So do not open the end cap without special reason.
Incorrect hoisting of pneumatic valves or electric valves will damage the actuators and valves. When transporting the valve on site, there is a lifting ring on the valve. Do not lift the valve or actuator through the valve stem. Therefore, during the installation phase, the most important step is to purge the pipeline before it is pressurized.

Valve maintenance
After the valve is installed, frequent maintenance is required to prevent the valve and drive equipment from malfunctioning. Every month, the valve in operation should be moisturized to optimize the performance of the valve.

Finally, there are some caveats:
1. Make sure that the start of the valve and the material list of valve control accessories conform to our specification sheet.
2. The valve packaging must be inspected to ensure that the exterior of the valve and components are intact during the transportation process, and all grease fittings are present.
3. Ensure that the valve process connection is covered to prevent dust and debris from entering the body cavity.
4. Pay attention to the valve manufacturer’s instructions for lifting and transporting the valve.
Tanghai Valve, a high-quality valve manufacturer, has better quality and longer service life. Escort your production work.

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

Gate valve structure diagram and working principle

August 4, 2021

Gate valve structure; Working principle of gate valve
Gate valve /stop valve structure:
The gate valve refers to a valve in which the gate closing member moves along the vertical direction of the center line

rising stem gate valve-open and closed position

of the passage. Generally, it consists of valve body, valve seat, valve stem, gate, valve cover, and sealing ring. It can be transformed into a variety of electric gate valves and pneumatic gate valves by equipping transmission devices and gate valves. It is used for full-open and full-close cut-off, and cannot be used for adjustment and throttling. ,
Gate valve structure diagram Gate valve working principle:
The gate of the gate valve moves linearly with the valve stem. Usually there is a trapezoidal thread on the lifting rod. Through the nut on the top of the valve and the guide groove on the valve body, the rotary motion is changed into linear motion, that is, the operating torque is changed. For operating thrust. When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, rely on the medium pressure to press the sealing surface of the gate to the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, the gate must be forced against the seat by external force to ensure the sealing performance of the sealing surface.

gate valve working diagram-3D GIF animated presentation

When the gate valve is opened, when the lift height of the gate is equal to 1:1 times the valve diameter, the fluid passage is completely unblocked, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as the mark, that is, the unmovable position, as its fully open position. In order to take into account the lock-up phenomenon caused by temperature changes, it is usually opened to the top position, and then rewind 1/2-1 circle, as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the gate (ie stroke).

Non-rising stem(NRS) and rising stem(RS) gate valve

August 4, 2021

structures and differences of Non-rising stem(NRS) gate valve and rising stem(RS) gate valve
RS gate valve structure picture, NRS gate valve structure picture

non-rising stem gate valve-open and close position

RS gate valve and NRS gate valve are different from the transmission mode. RS gate valve is a handwheel that drives a nut to rotate in place, and the stem is linearly raised and lowered to complete the switch; NRS gate valve is a handwheel that drives the stem to rotate, and there are threads in the gate. Nut) to move up and down to complete

the switch.
Structural principle of gate valve:
1. NRS gate valve structure: The stem nut is in the valve body and is in direct contact with the medium. When opening and closing the gate, it is realized by rotating the valve stem.
2. RS gate valve structure: the stem nut is on the bonnet or bracket. When opening and closing the gate, the stem nut is rotated to realize the lifting of the stem.

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

The difference between RS gate valve and NRS gate valve:
1. RS gate valve can see the screw, but NRS can not see the screw;
2. The RS gate valve raises or lowers the disc through the threaded transmission of the valve stem and the steering wheel; when the NRS gate valve is switched on and off, the steering wheel and the valve stem are connected and relatively immobile. It drives the valve through the rotation of the valve stem at a fixed point. The flap is lifted up and down to complete the opening and closing;
3. The transmission thread of the NRS gate valve is located inside the valve body. During the opening and closing process, the valve stem only rotates, and the gate is raised and lowered in the valve body; the valve stem of the RS gate valve drives the gate to rise and fall together, and the drive thread on the valve stem Outside the valve body, the opening and closing and position of the gate can be intuitively judged according to the movement direction and position of the valve stem;

rising stem gate valve-RS-BB OS&Y (3)

4. The height of the NRS gate valve is small; the RS gate valve requires a larger installation space;
5. The structure of the RS gate valve is beneficial to the lubrication of the valve stem, and the degree of opening and closing is obvious; the thread of the valve stem of the NRS gate valve is not only unable to be lubricated, but it is directly corroded by the medium and is easily damaged. Therefore, the RS gate valve is more widely used.

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

Representation method of electric gate valve model

July 27, 2021

Representation method of electric gate valve model; model name modification method; code name modification method
The electric gate valve is composed of an electric actuator and a gate valve body. The gate plate is controlled by the

gate valve (1)

power supply pressure to perform up and down linear operation to connect or close the fluid medium in the pipeline. The applicable pressure, temperature and caliber range are large, and it is especially suitable for Medium and large diameter pipes. Electric gate valves can be divided into various series. The actuators have on-off type and intelligent type, and the structure is very changeable. When selecting the type, the user should be familiar with the electric gate valve model preparation instructions to avoid selecting the wrong model, placing the wrong order and technology Unknown parameters caused problems such as exchange and return.
Electric 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.
The method of preparing the model of the electric gate valve:
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

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.

electric stainless steel gate valve

Description of electric gate valve model preparation:
Z941H-16P Stainless steel electric flange gate valve1. Z: represents gate valve;
2. 9: indicates that the transmission mode is electric;
3. 4: The connection method is flange connection;
4. 1: The structure is an open pole wedge single gate;
5. H: The sealing material is stainless steel;
6. 16: Indicates that the nominal pressure is 1.6MPa;
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

The difference between globe valve and gate valve

July 23, 2021

The difference between globe valve and gate valve, The difference between gate valve and globe valve

From the structure:
The length of the gate valve is shorter than that of the stop valve, and the height is higher than that of the stop valve. The installation of the rising stem gate valve should pay attention to the height. This should be paid attention to when the installation space is limited. The gate valve can be tightly closed with the sealing surface depending on the medium pressure, so as to achieve the effect of no leakage. When opening and closing, the valve core and the valve seat sealing surface are always in contact and rub against each other, so the sealing surface is easy to wear. When the gate valve is close to closing, the pressure difference between the front and rear of the pipeline is large, which makes the sealing surface wear more serious.

globe valve structure diagram

gate valve structure diagram

In principle:
The difference between the globe valve and the gate valve in principle is that the globe valve is a rising stem type, and the hand wheel rotates and rises together with the stem. In the gate valve, the hand wheel rotates and the valve stem moves upward. The flow rate is different, the gate valve is required to be fully open or fully closed, but the stop valve is not required. The shut-off valve has specified inlet and outlet directions; the gate valve has no inlet and outlet direction requirements.
Schematic diagram of gate valve Schematic diagram of globe valve
Explanation: The flow part of the gate valve is also the same as the straight pipe, but a gate is set in the pipe. If the gate is lifted up, the door will be fully opened, and the fluid of the stop valve will turn inside the valve. A 180-degree bend, usually the fluid enters from one side of the valve and after entering the valve, the fluid flows upward at a 90-degree angle, and then flows through the upper part of the valve body and then turns a 90-degree flow out, just as the fluid flows inside the valve. A cover is added to the upper outlet, the cover is closed and the door is closed, and the valve is opened when the cover is opened.

From the flow up:
The shut-off valve is low in and high out. From the outside, it is obvious that the pipeline is not on the horizontal line of one phase. The gate valve flow path is on a horizontal line. The stroke of the gate valve is larger than that of the stop valve.

globe cut-off valve working diagram-3D GIF animated presentation-flow direction

Explanation: From the perspective of flow resistance, the flow resistance of the gate valve is small when it is fully opened, and the flow resistance of the load stop valve is large. The flow resistance coefficient of ordinary gate valve is about 0.08~0.12, the opening and closing force is small, and the medium can flow in two directions. The flow resistance of ordinary globe valves is 3-5 times that of gate valves. When opening and closing, it needs to be forced to close to achieve the seal. The valve core of the stop valve does not contact the sealing surface when it is completely closed, so the wear of the sealing surface is very small. The stop valve that needs to add an actuator due to the main flow force should pay attention to the torque control mechanism Adjustment.

gate valve working diagram-3D GIF animated presentation-flow direction

From the installation:
1. The flow direction of the gate valve is the same when entering from both sides.
2. There are two ways to install the shut-off valve. One is that the medium can enter from below the valve core. The advantage is that the packing is not stressed when the valve is closed, which can prolong the service life of the packing and can be piped in front of the valve. Under pressure, the packing should be replaced; the disadvantage is that the driving torque of the valve is relatively large, which is about 1 times that of the upper flow, and the axial force on the valve stem is large, and the valve stem is easy to bend. Therefore, this method is generally only suitable for small-diameter stop valves (below DN50). For stop valves above DN200, the medium flows in from above. (The electric shut-off valve generally adopts the way that the medium enters from above.) The shortcoming of the medium entering method from above is just the opposite of that of the downward entering method.

From the sealing surface:
The sealing surface of the globe valve is a small trapezoidal side of the valve core (see the shape of the valve core for details). Once the valve core falls off, it is equivalent to closing the valve (if the pressure difference is large, of course the closing is not tight, but the anti-reverse effect is not bad). The gate valve is sealed by the side of the valve core gate plate, the sealing effect is not as good as the stop valve, and the valve core will not be closed like the stop valve when the valve core falls off.

You can check the detailed data sheet /specification /structure diagram /sizes /materials of

globe valve on:https://www.tanghaivalve.com/wp-content/uploads/2021/05/500-api-jis-globe-valve-cast-steel-forged-steel.pdf gate valve: https://www.tanghaivalve.com/wp-content/uploads/2021/05/301-data-sheet-gate-valve-th-valve.pdf

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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