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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

Working principle and movement mode of gate valve

August 13, 2020

The gate valve is a gate for opening and closing. The movement direction of the gate is perpendicular to the direction

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of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate valve is sealed through the contact between the valve seat and the gate plate. Usually, the sealing surface will be welded with metal materials to increase wear resistance, such as 1Cr13, STL6, stainless steel, etc. The gate has a rigid gate and an elastic gate. According to the difference of the gate, the gate valve is divided into a rigid gate valve and an elastic gate valve.

Working principle of gate valve:
The opening and closing part of the gate valve is a 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 has two sealing surfaces. The two sealing surfaces of the most commonly used model gate valve form a wedge. The wedge angle varies with valve parameters, usually 5°, and 2°52′ when the medium temperature is not high. The gate of the wedge gate valve can be made into a whole, called a rigid gate; it can also be made into a gate that can produce slight deformation to improve its manufacturability and compensate for the deviation of the sealing surface angle during the processing. The plate is called an elastic gate. When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, relying 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. The gate valve of the gate valve moves linearly with the valve stem, which is called the lifting stem gate valve, also called the rising stem gate valve. 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 turned into operating thrust. When the valve is opened, when the lift height of the gate is equal to 1:1 times the valve diameter, the fluid channel 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 position where it cannot be opened, as its fully open position. In order to take into account the locking phenomenon of temperature changes, it is usually opened to the top position, and then back 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, that is, the stroke. In some gate valves, the stem nut is set on the gate, and the rotation of the handwheel drives the rotation of the valve stem to lift the gate. This kind of valve is called a rotating stem gate valve, or a dark stem gate valve.

Movement mode of gate valve:
When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, only 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.

Movement mode: The gate of the gate valve moves linearly with the valve stem, which is also called the rising stem gate valve. 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 into operating thrust. When the valve is opened, when the lift height of the gate is equal to 1:1 times the valve diameter, the fluid channel 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 position where it cannot be opened, as its fully open position. In order to take into account the locking phenomenon due to temperature changes, it is usually opened to the top position, and then rewind 1/2-1 turn, as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the gate (i.e. stroke). Some gate valve stem nuts are set on the gate, and the rotation of the handwheel drives the rotation of the valve stem to lift the gate. This kind of valve is called Rotating stem gate valve or dark stem gate valve.

The difference between globe valve and check valve

August 13, 2020

With the development of high-tech industry, various valves are often used in daily life. Today we will understand the difference between globe valves and check valves.

The difference between globe valve and check valve:
1. Check valve and stop valve are not the same thing, the difference between the two is mainly that the structure is

Globe valve (6)

very different.

2. The check valve is a one-way valve, which automatically prevents the fluid from flowing in the reverse direction, without a knob, and cannot artificially block the forward flow.

3. The stop valve has a knob, which can artificially control the forward flow. Due to its special structure, even if there is no artificial pipe valve, the fluid cannot flow in the reverse direction.

Globe valve:

The globe valve, also known as the shut-off valve, is a forced sealing valve, so when the valve is closed, pressure must be applied to the disc to force the sealing surface to not leak. When the medium enters the valve from below the valve

lift-swing-check-valve-2

disc, the resistance that the operating force needs to overcome is the friction force of the valve stem and the packing and the thrust generated by the pressure of the medium. The force of closing the valve is greater than the force of opening the valve, so the valve stem The diameter of the valve must be large, otherwise the valve stem will bend failure.
working principle of globe valve:
The globe valve, also called the cut-off valve, is one of the most widely used valves. The reason why it is so popular is that the friction between the sealing surfaces is small during the opening and closing process, which is relatively durable, has a low opening height, and is easy to manufacture. , Easy maintenance, not only suitable for medium and low pressure, but also suitable for high pressure. The closing principle of the globe valve is to rely on the pressure of the valve stem to make the sealing surface of the disc and the sealing surface of the valve seat tightly fit to prevent the medium from flowing. Our country’s valve “Sanhua” once stipulated that the flow direction of the stop valve should be from top to bottom, so there is directionality when installing. The structural length of the stop valve is longer than that of the gate valve, and the fluid resistance is large, and the sealing reliability is not strong during long-term operation.

Check valve:

Check valve refers to the valve that automatically opens and closes the disc depending on the flow of the medium itself to prevent the medium from flowing back, also known as check valve, one-way valve, reverse flow valve, and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and the discharge of the container medium.

working principle of check valve:
Check valve refers to the valve that automatically opens and closes the disc depending on the flow of the medium itself to prevent the medium from flowing back. It is also called check valve, one-way valve, reverse flow valve and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and the discharge of the container medium. The check valve can also be used to supply the auxiliary system whose pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).

Valve manufacturers recommend:
Tanghai Valve Factory is a technological enterprise that produces globe valves and check valves. It designs and produces according to your needs, and provides you with professional, high-quality, low-priced valve products. Welcome to call us for quotations.

Electric globe valves’ structural features and installation attention

August 12, 2020

Structural features of electric globe valve:

1. Open and close without friction. This function completely solves the problem of traditional valves affecting the

Globe valve (6)

sealing due to mutual friction between the sealing surfaces.

2. Top-mounted structure. The valves installed on the pipeline can be directly inspected and repaired online, which can effectively reduce device shutdown and reduce costs.

3. Single valve seat design. Eliminates the problem that the medium in the valve cavity affects the safety of use due to abnormal pressure increase.

4. Low torque design. The valve stem with special structure design can be opened and closed easily with only a small handle.

5. Wedge-shaped sealing structure. The valve relies on the mechanical force provided by the valve stem to press the ball wedge onto the valve seat to seal, so that the sealing performance of the valve is not affected by changes in pipeline pressure, and the sealing performance is reliably guaranteed under various working conditions.

6. Self-cleaning structure of the sealing surface. When the ball is tilted away from the valve seat, the fluid in the pipeline passes through the sealing surface of the ball evenly at 360°, which not only eliminates the local erosion of the valve seat by the high-speed fluid, but also washes away the accumulation on the sealing surface to achieve the purpose of self-cleaning .

7. The valve body and bonnet with valve diameter below DN50 are die forgings, and the valve body and bonnet above DN65 are steel castings.

8. The connection forms of the valve body and the bonnet are different, clamp pin shaft connection, flange gasket connection and self-sealing thread connection.

9. The sealing surfaces of the valve seat and the valve disc are all made of plasma spray welding or surfacing welding of cobalt-chromium-tungsten cemented carbide. The sealing surface has high hardness, wear resistance, scratch resistance and long service life.

10. The valve stem material is nitrided steel. After nitriding, the surface of the stem has high hardness, wear resistance, scratch resistance, corrosion resistance and long service life.

Electric shut-off valve installation attention:

1. Pay attention to the flow direction of the medium when installing the valve, and install it strictly in the direction indicated by the valve flow direction arrow.

2. The valve can be installed at any position of the pipeline, and at the same time, choose a carbon steel or alloy steel valve according to the temperature of the medium and the medium.

3. The electric globe valve should be installed vertically as far as possible, with the valve stem upward.

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 and working principle of electric globe valve

August 12, 2020

Features of electric globe valve:

The fluid resistance is small, and its resistance coefficient is equal to that of a pipe section of the same length.
Globe valve (9)
Simple structure, small size and light weight. Electric globe valve
It is tight and reliable. The sealing surface material of the gate valve is widely used plastic, and it has good sealing performance. It has also been widely used in vacuum systems.
It is easy to operate and open and close quickly. It only needs to rotate 90° from fully open to fully closed, which is convenient for remote control.
The maintenance is convenient, the gate valve has a simple structure, the sealing ring is generally movable, and it is convenient to disassemble and replace.
When fully open or fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, and the medium will not cause erosion of the valve sealing surface when the medium passes.
It has a wide range of applications, with a diameter ranging from a few millimeters to a few meters, and can be applied from high vacuum to high pressure.

Electric globe valve classification:

According to its channel position, it can be divided into straight-through type and right-angle type.

Working principle of electric globe valve:

The working principle of the electric shut-off valve is to make the valve unblocked or blocked by rotating the valve. The gate valve switch is light, small in size, can be made into a large diameter, reliable in sealing, simple in structure, convenient in maintenance, the sealing surface and the spherical surface are often closed, and it is not easy to be eroded by the medium. It is widely used in various industries.

A. Opening process of globe check valve:

In the closed position, the valve body is pressed against the valve seat by the mechanical pressure of the valve stem.
When the hand wheel is turned counterclockwise, the valve stem moves in the opposite direction, and the angular plane at the bottom causes the ball to separate from the valve seat.
The valve stem continues to lift and interacts with the guide pin in the spiral groove of the valve stem, so that the ball begins to rotate without friction.
Until it reaches the fully open position, the valve stem is raised to the limit position, and the ball rotates to the fully open position.

B. Closing process of electric globe valve:

When closing, turn the handwheel clockwise, the valve stem begins to drop and the ball leaves the valve seat to start rotating.
Continue to rotate the hand wheel, and the valve stem will be acted on by the guide pin embedded in the upper spiral groove to make the valve stem and the gate rotate 90° at the same time.
When it is about to close, the gate body has rotated 90° without contact with the valve seat.
In the last few turns of the handwheel, the angular plane at the bottom of the valve stem mechanically wedges and presses the sphere to make it tightly press on the valve seat to achieve a complete seal.

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

Comparison of bellows globe valve and ordinary globe valve

August 12, 2020

Comparison of bellows globe valve and ordinary globe valve:

Globe valve (3)

1. Double sealing design (bellows + packing) If the bellows fails, the stem packing will also avoid leakage and meet international sealing standards.
2. There is no fluid loss, reducing energy loss and improving plant equipment safety.
3. Long service life, reduce maintenance times and lower operating costs.
4. The sturdy and durable bellows seal design ensures zero leakage of the valve stem and provides maintenance-free conditions.
5. The gas medium valve seat adopts PTFE soft sealing material to improve the sealing performance of this valve.
6. High temperature resistance≤425℃The valve seat adopts conical hard seal. Achieve airtight performance and zero leakage.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest globe valve manufacturers in China, main products are butterfly valves, check valves, gate valves and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, ISO, GB and other international standards. The main products are butterfly valves, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…), etc. Our products are widely used in various fields such as marine industry, shipbuilding, petrochemical, metallurgy, water treatment, fire fighting, water supply and drainage, etc. The company has won unanimous recognition and praise from customers with high quality and good reputation.

Classification of the globe valves-(2)

August 12, 2020

According to the classification of purposes, the globe valve can be divided into the following types:

12 Globe-valve-4

The fluorine-lined stop valve: it is suitable for various concentrations of aqua regia, sulfuric acid, hydrochloric acid, hydrofluoric acid and various organic acids, strong acids, strong oxidants, and various concentrations of strong alkali organic solvents and other Use on corrosive gas and liquid medium pipelines.

The national standard globe valve: it is the most commonly used product in the globe valve series. The API American standard globe valve and the American standard globe valve implement ANSI and API standards. The sealing surfaces of the disc and seat are made of Stellite cobalt-based hard with different hardness. It is made of alloy surfacing, with reliable sealing, high hardness, wear resistance, high temperature resistance, corrosion resistance, good scratch resistance and long life.

Needle valve: it is a small-caliber instrument valve, which plays a role of opening and closing and precise flow control in the instrument measurement pipeline system. It mainly includes power station instrument series, oil field special series, American standard series, etc.

Cryogenic globe valve: it usually refers to the valve whose working temperature is lower than -110℃, which is widely used in LNG, LPG and other low temperature industries. Since 2008, the globe valve with a suitable temperature of -196℃ can be manufactured, and all parts are pretreated with liquid nitrogen at low temperature to completely avoid seal deformation and leakage during use.

The plunger valve: it is also known as the plunger stop valve. Its sealing surface adopts a radial sealing structure. The load exerted on the valve cover by two elastic sealing rings sleeved on the polished plunger through the connecting bolts of the valve body and the valve cover The elastic sealing ring around the plug compresses the shut-off valve for sealing.

The insulation jacket cut-off valve: it adopts the insulation jacket design, using external heat source to circulate heating outside the valve, which can effectively prevent temperature loss when the medium passes through the valve and ensure the temperature of the medium.

The forged steel globe valve: it is designed and manufactured in accordance with API 602 standards, and provides three bonnet design forms: bolted bonnet, welded bonnet, pressure self-tightening bonnet, users can choose different forms according to their needs, providing RF flanges, NPT thread, SW welding type three connection methods.

The special oxygen stop valve: it is made of silicon brass or stainless steel with excellent material, which has the advantages of high mechanical strength, wear resistance, and good safety. Used in oxygen pipelines, it has the best explosion-proof and flame-retardant performance, eliminates the unsafe factors on the oxygen pipelines, and is widely used in the pipeline network of oxygen-using projects such as steel, metallurgy, petrochemical, and chemical industries. In addition to the functions of ordinary valves, it also has its own characteristics. Strict oil prohibition measures are adopted during manufacturing, and all parts are subjected to strict degreasing treatment before installation.

The bellows stop valve: it adopts a shaped stainless steel bellows design. The bellows reciprocating test is 10,000 times without failure, and the sealing performance is reliable. It is suitable for industrial and mining with inflammable, explosive, toxic and harmful media, and can effectively prevent valve leakage.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Details: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

Classification of the globe valves-(1)

August 12, 2020

According to the channel direction, the globe valve is devided into 4 types:

Globe valve (6)

1) Straight-through globe valve.
2) Direct flow stop valve: In direct flow or Y-shaped stop valve, the flow passage of the valve body is in a diagonal line with the main flow passage, so that the damage degree of the flow state is less than that of the conventional stop valve, so the pressure loss through the valve is also corresponding Is too small.
3) Angle type stop valve: In the angle type stop valve, the fluid only needs to change its direction once, so that the pressure drop through this valve is smaller than that of the conventional structure.
4) Plunger type globe valve: This type of globe valve is a variation of the conventional globe valve. In this valve, the disc and valve seat are usually designed based on the plunger principle. The valve clack is polished so that the plunger is connected to the valve stem, and the sealing is achieved by two elastic sealing rings sleeved on the plunger. The two elastic sealing rings are separated by a collar, and the sealing ring around the plunger is pressed firmly by the load exerted on the bonnet by the bonnet nut. The elastic sealing ring can be replaced and can be made of various materials. The valve is mainly used for “open” or “close”, but it is equipped with a special form of plunger or a special collar, which can also be used to adjust the flow .

The position of the thread on the valve stem:

1) Upper threaded stem stop valve: The thread of the stem of the stop valve is on the outside of the valve body. The advantage is that the valve stem is not corroded by the medium and is convenient for lubrication. This structure is more common.

2) Bottom thread stem stop valve: The thread of the stem of the stop valve is in the valve body. The stem thread of this structure is in direct contact with the medium, which is susceptible to corrosion and cannot be lubricated. This structure is used in places with small diameters and low temperatures.

There are many domestic manufacturers of globe valves, and most of the connection sizes are not uniform. It is mainly divided into the following categories: General category based on JB/T2203-1999 “Structural Length of Stop Valves”. At present, most domestic shut-off valve manufacturers design and produce according to this standard. However, this standard is not perfect, and the specifications are not complete. The maximum nominal diameter of a single gate valve is DN1200, and the maximum nominal diameter of a double gate valve is DN1500. According to the specifications of the shut-off valve produced by the manufacturer and the information available, the smallest nominal diameter of the angle-type shut-off valve is DN15, and the nominal diameter of the Z-type straight-through shut-off valve reaches DN2000. After research, the connection size of each manufacturer is not uniform. In order to have a unified standard, users can interchange the same specifications when selecting and installing, it is recommended that China General Machinery Research Institute revise JB/T2203-1999 “Structural Length of Stop Valves”. It is recommended that the design institute and users choose according to the standard, and the stop valve manufacturer should design and manufacture according to the standard.

The working principle and characteristics of the globe valve

August 12, 2020

The globe valve is a tool that relies on the pressure of the valve stem to make the sealing surface of the disc and the sealing surface of the valve seat tightly fit to prevent the flow of the medium. It is a forced sealing valve and is one of the most widely used valves.

According to the direction of the passage, the globe valve is divided into four types: straight-through globe valve, direct-flow globe valve, angle globe valve and plunger globe valve.
1. Working principle of globe valve:

Globe valve (9)

The stop valve, also called the cut-off valve, is one of the most widely used valves. The reason why it is popular is that the friction between the sealing surfaces is small during the opening and closing process, which is relatively durable, has a small opening height, and is easy to manufacture. , Easy maintenance, not only suitable for medium and low pressure, but also suitable for high pressure. The closing principle of the shut-off valve is to rely on the pressure of the valve stem to make the sealing surface of the disc and the sealing surface of the valve seat closely fit, preventing the flow of the medium. Our country’s valve “Sanhua” once stipulated that the flow direction of the stop valve should be from top to bottom, so there is directionality when installing. The structural length of the shut-off valve is longer than that of the gate valve, and the fluid resistance is large, and the sealing reliability is not strong during long-term operation.

As one of the most important cut-off valves, the globe valve plays an important role in the aerospace field. As an important component of aerospace equipment, the shut-off valve realizes the functions of medium transportation, cut-off, and adjustment, and its sealing performance directly affects the safe and reliable operation of aerospace equipment. Studying the influencing factors and influencing rules of the sealing characteristics of typical globe valves has guiding significance for the structural design of the valve sealing pair, thereby improving the sealing performance and reliability of the valve.

2. Globe valve characteristics:

The valve plays an important role in cutting off and throttling the medium in the pipeline. As an extremely important cut-off valve, the valve is sealed by applying a torque to the valve stem, and the valve stem is in the axial direction. The valve clack applies pressure to make the sealing surface of the valve clack closely fit the sealing surface of the valve seat, and prevent the medium from leaking along the gap between the sealing surfaces.

The sealing pair of the globe valve is composed of a valve flap sealing surface and a valve seat sealing surface, and the valve stem drives the valve flap to move vertically along the center line of the valve seat. During the opening and closing process of the globe valve, the opening height is small, the flow is easy to adjust, and the manufacturing and maintenance are convenient, and the pressure application range is wide.

Compared with another commonly used shut-off valve in industrial production, an alarm valve, the shut-off valve is simpler than the former in terms of structure, and is easy to manufacture and maintain. In terms of service life, the sealing surface of the globe valve is not easy to wear and scratch. During the opening and closing process of the valve, there is no relative sliding between the valve disc and the sealing surface of the seat, so the wear and abrasion of the sealing surface are small, so the sealing is improved. During the full closing process of the auxiliary service life stop valve, the disc stroke is small, and its height is relatively small compared to the alarm valve. The shortcoming of the globe valve is that the opening and closing torque is large and it is difficult to achieve rapid opening and closing. Because the flow passage in the valve body is relatively tortuous, the fluid flow resistance is large, and the fluid power is lost in the pipeline.

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

Features and working principle of silent check valve

August 11, 2020

Silent check valve refers to a valve that automatically opens and closes the disc depending on the flow of the medium itself to prevent the medium from flowing back. It is also called check valve, one-way valve, silence check valve, reverse flow valve, and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and discharge the container medium. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).
Features of silent check valve:
1. The valve clack adopts a “bullet” shape design, and the valve body adopts a “waist drum” shape design to improve the flow direction of the medium and reduce the flow resistance coefficient.

2. The valve adopts a short structure. Although the head loss is slightly larger than that of the lift-type silent check valve, it is small in size and inexpensive.

3. Compact structure, non-metallic lubrication sleeve is installed between the guide shaft and the guide frame, and the valve flap can be raised and lowered flexibly without locking phenomenon.

4. The skeleton type rubber sealing ring is directly embedded in the valve body, which avoids the direct erosion of the sealing ring by the medium for a long time, and the service life is si

silent check valve (11)

gnificantly prolonged, and it is strong and durable.

5. The valve flap has a short opening and closing stroke, which can effectively prevent water hammer

6. It is suitable for water supply and drainage system and high-rise building pipe network. It can be installed at the outlet of the pump. The structure is slightly modified, and it can be used as a suction bottom valve, but it is not suitable for sewage pipe network.

7. It has small size, light weight, low fluid resistance, fatigue resistance and long life
working principle of silent check valve:
When the medium flows in the specified direction, the valve flap is opened by the force of the medium; when the medium flows backward, the valve flap is tightly closed with the sealing surface of the valve seat due to the weight of the valve flap and the opposing force of the medium. Closed to achieve the purpose of preventing the backflow of the medium.

Check valve is an automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, and the release of the container medium. Check valves can also be used to supply pipelines for auxiliary systems whose pressure may rise above the system pressure.

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

Posts

Gate valve characteristics and installation notes

Working principle and movement mode of gate valve

The difference between globe valve and check valve

Electric globe valves’ structural features and installation attention

Characteristics and working principle of electric globe valve

Comparison of bellows globe valve and ordinary globe valve

Classification of the globe valves-(2)

Classification of the globe valves-(1)

The working principle and characteristics of the globe valve

Features and working principle of silent check valve

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