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The sealing characteristics and principle of eccentric butterfly valve

July 26, 2021

Basic knowledge of eccentric butterfly valve: eccentric butterfly valve, also called offset butterfly valve; Eccentric butterfly valves can be divided into various types, generally single eccentric sealing butterfly valves, double eccentric sealing butterfly valves, and triple eccentric sealing butterfly valves.
Features of single eccentric sealing butterfly valve:
In order to solve the problem of squeezing between the butterfly plate and the valve seat of the concentric butterfly valve, a single eccentric butterfly valve was produced. Disperse and reduce the excessive squeezing between the upper and lower ends of the butterfly plate and the valve seat. However, because the single eccentric structure does not disappear during the entire opening and closing process of the valve, the scratching phenomenon between the butterfly plate and the valve seat has not disappeared, and the application range is similar to that of the concentric butterfly valve, so it is not used much.

Double eccentric-lug butterfly valve-D72F-150lbP-stainless steel (4)

The single eccentric sealing butterfly valve has the following characteristics:
1. It has a sealing structure with reliable performance and long service life.
2. It has a truss structure with small flow resistance, good rigidity and small pressure loss.
3. The valve plate sealing ring is easy to replace and easy to maintain.
4. The valve plate sealing ring adopts a “T”-shaped structure, and the sealing pair is linearly sealed.
5. The bottom end of the valve adopts bimetal thrust washer, which has excellent thrust performance.
6. The valve can be installed vertically or horizontally, with good applicability.
7. This type of valve is recommended to be used in one direction, and it can be used in two directions when the reverse sealing requirements are not strict.
8. When the valve is completely closed, the leakage of the seal test is zero.
9. Replace the valve plate sealing ring, O-ring, valve body, valve plate, shaft and other materials, which can be applied to a variety of media and different temperatures.
Features of double eccentric sealing butterfly valve:
On the basis of the single eccentric butterfly valve, the double eccentric butterfly valve is the most widely used double eccentric butterfly valve. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved. The scraping is greatly reduced, and at the same time, the double eccentric butterfly valve can also use a metal seat, which improves the application of the butterfly valve in the high temperature field. But because its sealing principle is a positional sealing structure, that is, the sealing surface of the butterfly plate and the valve seat is in line contact, and the elastic deformation caused by the butterfly plate squeezing the valve seat produces a sealing effect, so the closed position is very demanding (especially metal Valve seat), low pressure bearing capacity, which is why traditionally people think that butterfly valves are not resistant to high pressure and have large leakage.
The main features of the double eccentric butterfly valve are as follows:

1. Adopting full flow design, not affected by impurity jamming. The conjoined “O”-shaped sealing line at both ends makes the pipeline installation without gaskets and maintains a reliable seal. Different materials can be selected according to different usage requirements.
2. The butterfly plate material adopts streamlined design, which can be used in two directions, with low flow resistance and excellent flow characteristics.
3. The shaft pin adopts the unpinning structure, which can tightly combine the butterfly valve stems without weakening the strength of the shaft and has good interchangeability.
4. The valve body connection can be applied to ANSI125/150, DIN2501 PN10/16, JISB2210 10K, JIS G5527 7.5K standards.
Features of triple eccentric sealing butterfly valve:

triple offset butterfly valve-double flange- (4)

1. API specifications
2. Double safety structure
3. No dead zone design
4. Body valve seat structure
5. Thin layer valve seat structure
6. Replaceable seal pair
7. Balanced fixed structure
8. Intrinsic refractory structure
9. High sealing packing structure
The structural feature of the triple eccentric butterfly valve is that while the double eccentric valve stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the cylinder axis of the body, that is to say, after the third eccentricity, the butterfly plate seals The cross-section is no longer a true circle, but an ellipse, and the shape of the sealing surface is therefore asymmetrical. One side is inclined to the center line of the body, and the other side is parallel to the center line of the body. The biggest feature of this third eccentricity is that the sealing structure is fundamentally changed. It is no longer a positional seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely relies on the contact surface pressure of the valve seat to achieve the seal. Therefore, the problem of zero leakage of the metal valve seat is solved in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance is also solved. Since its inception, the triple eccentric butterfly valve itself has undergone a process of self-improvement and continuous development in order to meet the increasingly severe requirements of working conditions. Even if the highest zero leakage is required, the triple eccentric butterfly valve can theoretically be achieved, but in fact it still relies on careful design and precision manufacturing.
Related knowledge: features of eccentric butterfly valve; Installation instructions of double eccentric butterfly valve

Related products: Electric triple eccentric butterfly valve Pneumatic triple eccentric butterfly 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 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

Gate valve model meaning and representation method

July 22, 2021

Gate valve model representation method | Gate valve model meaning
Explanation of the meaning of the gate valve model:

pneumatic gate valve (3)

Gate valve is one of the more common types of shut-off valves. It is generally suitable for full-open or full-close two-position operation control. It is mainly used to close the medium in the pipeline. It is usually called a cut-off valve or a blocking valve. With the increase in demand for valves and the expansion of demand in the machinery industry, gate valves have become an indispensable part of modern industrial control systems. For more and more complex working conditions and harsh use requirements, the correct selection of gate valve models is related to the adaptability of the pipeline medium and an important guarantee for the safety of the working conditions. The user should have a detailed understanding of the method of preparing the gate valve model to avoid problems such as selecting the wrong model, placing the wrong order, and unclear technical parameters resulting in replacement and return.
This compilation method is the representation method of the standard gate valve model in my country. It mainly explains in detail 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 and need to be explained separately.
The method of formulating and expressing gate valve model:
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.

Knife-gate-valve-1-

Example of preparing gate valve model:
PZ973H-16C Electric Wafer Type Knife Gate Valve

1. PZ: stands for knife gate valve;
2. 9: indicates that the transmission mode is electric;
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. 16: Indicates that the nominal pressure is 1.6MPa;
7. C: Indicates that the valve body material is carbon 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

Principle of Globe Valve (Figure)

July 21, 2021

Globe Valve is also called stop valve, shut-off valve. The opening and closing part of the globe valve is a plug-shaped valve disc, the sealing surface is flat or cone, and the valve disc moves linearly along the centerline of the fluid. The movement form of the valve stem includes a lifting rod type (the valve stem is raised and lowered, the hand wheel does not lift), and there is a lifting rotating rod type (the hand wheel and the valve stem rotate and lift together, and the nut is set on the valve body). The stop valve is only suitable for fully open and fully closed, adjustment and throttling are not allowed.
Brief introduction to the principle of the globe valve:

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

To put it simply, the principle of the globe valve is to use the torsion of the valve stem to give a downward pressure on the sealing surface, and rely on the pressure of the valve stem to make the disc sealing surface and the valve seat sealing surface closely fit to prevent the inflow of the medium or adjust the flow rate of the medium. . The opening and closing part of the stop valve is a cylindrical valve disc, the sealing surface is flat or conical, and the valve disc moves linearly along the center line of the fluid. The movement mode of the valve stem includes a lifting rod type (the valve stem is raised and lowered, and the hand wheel does not lift), and there is also a lifting rotating rod type

Schematic diagram of shut-off valve (closed state)

(the hand wheel and the valve stem rotate and lift together, and the nut is set on the valve body). The globe 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.

The working principle of the stop valve:
We assume that there is a pipe with a lid. Water flows in from the bottom of the pipe and flows out toward the nozzle. The lid of the outlet pipe is equivalent to the closing part of the shut-off valve. If the pipe lid is lifted up by hand, the water will flow out. When the cap is closed, the water stops flowing, which is equivalent to the working principle of a shut-off valve.

The shut-off valve relies on rotating the hand wheel to make the valve stem rise and fall, and drive the valve disc to make a linear displacement parallel to the flow direction of the medium to achieve the purpose of opening and closing. The handwheel rotates in a clockwise direction, and the working medium enters from the channel under the valve disc. At this time, the applied sealing force must be equal to or greater than the sum of the required specific pressure generated on the sealing surface and the upward force of the medium.

Schematic diagram of shut-off valve (open state)

When the shut-off valve is opened, when the opening height of the disc is 25% to 30% of the nominal diameter, the flow has reached the maximum, indicating that the valve has reached the fully open position. Therefore, the fully open position of the shut-off valve should be determined by the stroke of the valve disc.
Note:
1. The shut-off valve only allows the medium to flow in one direction, and has directionality when installed. ,
2. The function of the shut-off valve is either 0 or 1, either through or not through. In other words, the shut-off valve is only suitable for fully open and fully closed, and adjustment and throttling are not recommended.

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

Electric globe valve selection and application

July 20, 2021

Electric shut-off valve selection, Electric shut-off valve application, globe valve also named shut off valve or cut off valve.
Advantages of electric shut-off valve:
Once the electric shut-off valve is in the open state, there is no contact between its valve seat and the sealing surface of the disc, so its sealing surface is less mechanically worn, because most of the electric shut-off valves have relatively easy repairs. Or there is no need to remove the entire valve from the pipeline when replacing the sealing

electric globe valve

element,which is very suitable for the occasion where the valve and the pipeline are welded together. The most obvious advantage is that during the opening and closing process, the friction between the disc and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant. The opening height is generally only 1/4 of the diameter of the valve seat passage, so it is much smaller than the gate valve. Usually there is only one sealing surface on the valve body and the valve flap, so the manufacturing process is better and it is easy to maintain. The flow direction of the medium through this type of valve has changed, so the flow resistance of the electric shut-off valve is higher than that of other valves.

Selection of electric shut-off valve:
Commonly used electric globe valves are electric straight-through globe valves, electric throttle valves, electric angle globe valves, electric DC globe valves, electric plunger globe valves, etc. In addition to electric throttle valves, other electric globe valves generally do not Make high-pressure choices.
1. Angle type electric shut-off valve; in the angle type electric shut-off 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 of the electric shut-off valve.
2. DC type electric shut-off valve; electric shut-off valve in the DC type or Y-shaped electric shut-off valve, the flow passage of the valve body is in a diagonal line with the main flow path, so that the degree of damage to the flow state is smaller than that of the conventional electric shut-off valve, so it passes The pressure loss of the valve is correspondingly small.
3. Plunger type electric shut-off valve: This type of electric shut-off valve is a modification of the conventional electric shut-off 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 and the valve stem are connected, and the sealing is achieved by two elastic sealing rings sleeved on the plunger. The two elastic sealing rings are separated by a sleeve ring, and the sealing ring around the plunger is pressed firmly by the load exerted on the bonnet by the bonnet nut.
Electric shut-off valve application:
If the electric shut-off valve is used in high-pressure occasions, it is generally connected by butt welding, or electric angle type shut-off valve is used. According to the material, you can choose carbon steel or 304 stainless steel. If the temperature is relatively high, you need to choose chromium-molybdenum steel or chromium-molybdenum-vanadium steel. The typical J941Y-170V electric high temperature and high pressure stop valve used in power plants.

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

Ball valve installation and maintenance methods

July 19, 2021

Ball valve installation:
1. It must be confirmed that the pipeline and valve have been cleaned before operation.
2. The actuator operation of the valve drives the valve stem to complete rotation according to the size of the input signal: when it rotates 1/4 turn (900) in the forward direction, the valve is closed. When the reverse rotation is 1/4 turn (900), the valve opens.

fixed ball valve

3. When the direction indicator arrow of the actuator is parallel to the pipeline, the valve opens; when the arrow is perpendicular to the pipeline, the valve closes.
Ball valve repair:
Longer service life and maintenance-free time will depend on several factors: under normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data. Note: When the ball valve is closed, the fluid pressure in the valve body It still exists. Before maintenance, remove the pipeline pressure and leave the valve in the open position. Before maintenance, disconnect the power supply or air supply. Before maintenance, disconnect the actuator from the bracket.

electric ball valve

1. Packing lock If the packing culvert is slightly leaking, the valve stem nut must be locked. Note: Do not lock, usually lock 1/4 ring to 1 ring, the leakage will stop.
2. Replace the valve seat and seal
A. Disassembly Keep the valve in the half-open position to flush out the dangerous substances that may exist inside and outside the valve. Close the ball valve, remove the bolts and nuts of the flanges on both sides, and completely remove the valve from the pipeline. Disassemble the drive device-actuator, connecting bracket, lock washer, stem nut, butterfly shrapnel, glam, wear-resistant sheet, stem packing in order. Remove the body cover connecting bolts and nuts, separate the valve cover from the valve body, and remove the valve cover gasket. Make sure that the valve ball is in the “off” position. This will make it easier to take it out of the valve body, and then remove the valve seat. Gently push the valve stem down from the hole in the valve body until it is completely taken out, and then take out the O-ring and packing ring. Note: Please operate carefully to avoid scratching the surface of the valve stem and the packing seal of the valve.
B. Reassembly Clean and inspect the parts under investigation. It is strongly recommended to replace the valve seat and bonnet gaskets and seals with spare parts kits. Reverse the order of disassembly and assembly. Use the specified torque to tighten the flange bolts crosswise. Tighten the nut with the specified torque. After installing the actuator, rotate the valve stem to drive the valve core to rotate the corresponding input signal to make the valve open and close. If possible, after installing the pipeline, test the sealing pressure and performance of the valve according to the standard.
Related knowledge: The role of the ball valve The working principle of the ball 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 role and use of the ball valve

July 16, 2021

The function of the ball valve:
The opening and closing part of the ball valve is a round sphere with a hole. The ball core rotates around the axis of the valve stem by 0-90° back and forth to achieve the purpose of opening or closing the valve. Ball valves have many functions. They are generally used to switch off or adjust the medium in the pipeline. Among them, the three-way ball valve can flexibly cut off, distribute and change the flow direction of the medium. The sealing surface of the ball valve is usually closed with the spherical surface, so it is not easy to be eroded by the medium. It is easy to operate and has a simple and compact structure. It can be used in working conditions such as water, natural gas, acid, and solvent.

fixed ball valve

The application of the ball valve:
Ball valves can generally be divided into three categories: floating ball valves, fixed ball valves, and elastic ball valves according to their structure. According to the different sealing performance, it is divided into hard-sealed ball valves and soft-sealed ball valves. The soft-sealed ball valves have better sealing performance and can achieve zero leakage. They are generally used in normal temperature and pressure pipelines with corrosive media, while hard-sealed ball valves are not only It can be used in normal temperature and pressure, as well as pipelines with low temperature and low pressure and high temperature and high pressure.
(1) Floating ball valve
The ball of the floating ball valve is floating and is supported by two valve seats. Under the action of the medium pressure, the ball can produce a certain displacement and tightly adhere to the sealing surface of the valve seat at the outlet end to ensure that the outlet end is sealed. However, if the sphere bears the load of the working medium and is all transmitted to the outlet sealing ring, the sphere may deviate when it is impacted by a higher pressure. Therefore, the ball valve of this structure is generally suitable for normal pressure or low pressure working conditions.
(2) Fixed ball valve

Pneumatic electric high platform ball valve

The name of the fixed ball valve is that the ball is fixed, and when the valve is closed, the ball valve will not move even if it is pressurized. Fixed ball valves are equipped with a floating seat. After being pressured by the medium, the seat will move so that the sealing ring is pressed tightly on the sphere to ensure sealing. Generally, sliding bearings or rolling bearings are installed on the upper and lower shafts of the ball, which can be operated with a small torque and a small torque, and is generally suitable for high-pressure and large-diameter pipelines.
Other common classifications of ball valves, chip ball valves, orbital ball valves, V-shaped ball valves, O-shaped ball valves, cut-off ball valves, three-way ball valves, four-way ball valves, forged steel ball valves, ash unloading ball valves, anti-sulfur ball valves, eccentric ball valves, thermal insulation ball valves, pneumatic Ball valves, electric ball valves, ferrule ball valves, welded ball valves. Among them, the V-shaped ball valve has a shearing effect, which is especially suitable for media containing fibers, small solid particles, slurry and other media. The three-way ball valve can also be divided into T-type and L-type. The T-shape can make the three intersecting pipelines connect to each other or cut off any one of the channels, playing the role of splitting and merging. The L-shape only connects two perpendicular pipes, and cannot connect to the third pipe at the same time, and it mainly plays a role of distribution.
Related knowledge: working principle of ball valve structure diagram of ball 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

Types and classifications of globe valve

July 16, 2021

Type of globe valve / Classification of globe valve
The globe valve, also called the shut off valve or cut-off valve, is the most widely used valve, which is mainly composed of a valve body, a valve clack, a valve cover, and a valve stem. The valve body and valve cover are pressure-bearing parts, and the valve clack and valve stem are internal parts. The shut-off valve is a valve in which the closing part (disc) moves along the center line of the valve seat. According to this movement form of the valve disc, the change of the valve seat port is proportional to the valve disc stroke.

Classification of stop valves:
According to the structure of the valve body, the globe valve is divided into right-angle type, straight-through type and direct-flow type.
1. The right-angle fluid only needs to change its direction once, so that the pressure drop through this valve is smaller

than that of a conventional shut-off valve. The valve body is mostly forged, which is suitable for shut-off valves with smaller passages and higher pressures.

right-angle Globe valve (2)

2. The straight-through type is the most common structure. The medium inlet and outlet channels are 180° in the same direction, but the fluid resistance is the largest.

straight-through Globe valve (9)

3. In the direct-flow or Y-shaped stop valve, the flow channel of the valve body is in an oblique line with the main flow channel, and the fluid resistance is small. It is mostly used for fluids containing solid particles or high viscosity.

Y-shaped Globe valve (1)

Type of stop valve:
According to nominal pressure: vacuum, low pressure, medium pressure, high pressure, ultra high pressure valve, etc.;
According to working temperature: high temperature, medium temperature, normal temperature, low temperature, ultra-low temperature valve, etc.;

According to the driving mode: manual valve, power driven valve (electromagnetic, pneumatic, hydraulic, electric and various linkage valves), automatic valve, etc.;
According to the valve body material: cast iron, cast copper, cast steel, carbon steel, titanium, stainless steel valves, etc.;
By application sector: general purpose valves, power station valves, marine valves, metallurgical valves, pipeline valves, plumbing valves, etc.;
According to the structure: straight-through type, angle type, direct current type, etc.;
According to the connection form: internal thread, external thread, flange, welding,

clamp, clamp, ferrule, etc.;

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

Globe valve structures and design standard

July 15, 2021

Globe valve structure, Globe valve design standard
The shut-off valve is a particularly common shut-off valve, which is mainly used to connect or cut off the medium in the pipeline, and is generally not used to adjust the flow. The globe valve is suitable for a wide range of pressure and temperature, but it is generally used for medium and small diameter pipelines.

Globe valve (2)

Globe valve (1)

Globe valve (9)

Structural principle of globe valve:
1. The center of the inlet and outlet of the shut-off valve are on the same straight line, and the fluid flows like an S-shaped sphere, so it is also called a spherical shut-off valve.
2. When the valve seat of the valve stem descends toward the bottom sealing surface and is pressed down, the medium stops flowing; when the valve stem rises, the medium passes through the flow path from below to above.
Globe valves generally have direction requirements during installation. The flow direction of the medium in the pipeline generally flows from bottom to top through the valve seat port, which is what we often call the so-called “low inlet and high outlet”. The purpose of this is to reduce fluid resistance and save effort in opening. In the closed state, the valve stem and the packing culvert are not in contact with the medium to ensure that the valve stem and the packing culvert are not damaged or leaked.

Globe valve structure diagram Globe valve structure and design standards:

name	Globe valve structure	Globe valve design standard
Typical Forged Steel Globe Valve	1. Flow channel JB/T 7746-1995: Shrinkage hole BS5352-1999: Through hole or shrinkage hole (CL150~800); Through hole (Cl1500) JPI-7S-36-1999: Through hole 2. Valve body and bonnet Connection: flange, thread or welding 3. Connection end JB/T 7746-1995: internal thread, socket welding or flange BS5362-1999: internal thread, socket, flange and butt welding JPI-7S-36- 1999: Internal thread, socket	JB/T 7746-1995 BS 5352-1999 JPI-7S-36-1999
Internal pressure self-sealing forged steel globe valve	1. Flow path: shrinkage hole 2. Connection between valve body and bonnet: internal pressure self-sealing 3. Connection end: butt welding, flange or socket	ASME B16.34-1996
Cast steel globe valve	1. Flow path: angle type, straight-through, direct current (Y type) 2. Connection between valve body and bonnet: flange 3. Connection end: flange or butt welding 4. Various types of discs can be used, Usually exposed rod, there are also a few smaller diameter valves with dark rod	JPI-7S-46-1999 JIS B2071-1999 JIS B2072-1999 JIS B2081-1999 JIS B2082-1999 BS 1873-1999 MSS-SP-42-1999 GB/T 12235-1989 BS 5160-1989
Bellows Sealed Globe Valve	1. Flow path: angle type, straight-through, direct current (Y type) 2. Connection between valve body and bonnet: flange 3. Connection end: flange or butt welding 4. Various types of discs can be used, It is usually an exposed stem, but there are also a few valves with smaller diameters that use double stem seals with concealed stem 5, bellows and packing	ASME B16.34-1996
Angle type high pressure globe valve	1. Flow path: angle type 2. Connection between valve body and bonnet: thread, clamp or welding 3. Various types of discs can be used. For ultra-high pressure valves, internal pressure self-balancing discs are usually used 4. The valve body can adopt integral type, two-piece type 5. Connection end: flange or butt welding	ASME B16.34-1996 GB/T 12235-1989
Lining stop valve	1. Flow channel: angle type, straight-through, direct current (Y type) 2. Connection between valve body and bonnet: flange 3. Connection end: flange or butt welding 4. Lining material is rubber, plastic, etc.	ASME B16.34-1996
Two-way three-way globe valve	1. Flow path: two-way three-way flow path 2. Connection between valve body and bonnet: flange 3. Connection end: flange or butt welding	ASME B16.34-1996
Cast steel discharge stop valve	1. Flow path: straight-through 2. Connecting end: flange 3. Disc: upward or downward expansion 4. Connection between valve body and bonnet: flange	ASME B16.34-1996
Three-way globe valve	1. Flow path: Tee 2. Connecting end: Flange 3. Disc: Plane seal	ASME B16.34-1996
Pressure gauge shut-off valve	1. Flow path: DC, right angle, three-way 2. Connection between valve body and bonnet: integral forging or thread 3. Connection end: external thread, clamp 4. Disc: Cone and flat	ASME B16.34-1996
Water seal stop valve	1. Flow path: DC 2. Connection end: socket welding, butt welding 3. Valve body and bonnet: both forged, with a chromium nickel steel or carbon steel 4. Disc: Cone seal (DN10~25mm) , Plane seal (DN32~200mm)	E101-1999 GB/T 12235-1999 ASME B16.34-1996
Slurry shut-off valve	1. Flow path: DC 2. Connection end: Flange 3. Valve body structure: The valve seat is clamped between the left and right valve bodies, and the left and right valve bodies are connected by bolts. 4. The valve body and the bracket are connected by bolts. 5. The valve cover: CL150 is forged as a whole, CL300 and CL400 are split type, using strut connection. 6. Disc: Cone surface is sealed into plane seal, or throttle type sealing surface is overlaid with hard alloy	GB/T 12235-1989 ASME B16.34-1996
Angle globe valve	1. Flow path: right angle 2. Connection end: flange 3. Valve body and bonnet: forged throttling type. The sleeve is drilled and the piston moves up and down in the sleeve to adjust the flow. 4. Valve body, valve Cover connection: bolt connection	API 6A-2002
Titanium Globe Valve	1. Flow path: straight-through 2. Valve body, bonnet, stuffing box, valve clack, valve stem are made of titanium 3. Valve body and bonnet connection: bolt connection 4. Valve clack is flat seal	GB/T 12235-1989

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

Schematic diagram of electric ball valve structure

July 14, 2021

The electric ball valve has a simple structure and is composed of a few parts. It has the advantages of small size, light weight, small installation size, small driving torque, easy operation and agility, and it can be quickly opened and closed only by rotating 90°. It has a good flow regulating effect and sealing characteristics; in the application range of large and medium caliber, medium and low pressure, the electric ball valve is one of the leading valves, and it is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline. When the electric ball valve is fully opened, there is no resistance when the medium flows through the ball core port, so the pressure drop that occurs through the valve is very small, so it has better flow control characteristics.

O type ball valve O shaped ball core

Electric ball valve structure: There are many types of electric ball valves, which are generally divided into two categories according to different structural forms, namely O-shaped structure and V-shaped structure. The valve ball openings of the two are different, and the application is also different. O-type is generally suitable for shutting off. Use, occasionally adjust, but V-type is more suitable for adjustment (large adjustable ratio).

O-type ball valve structure:
The O-shaped ball valve is equipped with a ball with a middle through hole inside the valve body. A through hole with the same diameter as the pipe diameter is opened on the ball. When it is fully opened, it is a non-block valve with a large flow capacity and no directionality when fluid enters the valve. The sphere can rotate in the sealing seat, and there is a ring-shaped elastic body on both sides of the pipeline direction to achieve sealing. By rotating the ball 90°, the direction of the through hole can be changed, thereby realizing the opening and closing of the ball valve. ,

V-shaped ball valve structure:

V type ball valve, V-shaped ball core

The V-shaped ball valve core has a V-shaped structure. The valve core is a 1/4 spherical shell with a V-shaped gap. With the rotation of the ball, the opening area changes, but the shape of the opening surface is always triangular, and the flow characteristics are similar. Percentage, the adjustable ratio is large. It has the characteristics of large flow capacity, large adjustable range, shearing force, and tight closing. It is especially suitable for working conditions where fluid materials are fibrous. Generally, V-type ball valves are single-sealed ball valves. Not suitable for bidirectional use.
Related knowledge: The difference between O-shaped ball valve and V-shaped ball valve
Related products: Electric V-shaped ball valve Pneumatic O-shaped ball 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

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