1. The structure of the shut-off valve is simpler than that of the gate valve. It’s easy to manufacture and repair.

2. The sealing surface of the shut-off valve is not easy for wear and abrasion. The sealing performance is good. There is no relative sliding between the valve flap and the sealing surface of the valve body when sanitary shut-off valve is opened or closed so that neither the wear nor the abrasion is serious.

The sealing performance is good. The service life is long. The area of the sealing surface is small, and the structure is relatively simple. The required hours for manufacturing the sealing surface and the expensive materials required for the sealing ring are both less than those of the gate valve.

3. When the shut-off valve is opened or closed, the stroke of the valve flap is small, so the height of the shut-off valve is lower than that of the gate valve, but its structural length of it is longer than that of the gate valve.

4. The opening and closing torque of the shut-off valve is large, so it takes some effort to open and close the valve, and it takes some time to open and close the valve.

5. The fluid resistance of the shut-off valve is large, due to the fact that the medium channel inside the valve body is winding. The bigger the fluid resistance, the more the momentum is consumed.

6. Shut-off valve is not suitable for a medium that has particles, large viscosity, and is easy to coke.

7. The regulating performance of the shut-off valve is relatively poor.

8. When the nominal pressure PN is equal to or less than 16MPa, downstream is commonly used, with the medium moving upwards from below the valve flap. When the nominal pressure PN is equal to or larger than 20MPa, countercurrent is commonly used, with the medium moving downwards from above the valve flap to increase the sealing performance. When in use, the medium of the shut-off valve can only move in a single direction, the flow direction of it can’t be changed.

9. When the shut-off valve is fully open, the valve flap is often affected by erosion.
10. Shut-off valve uses screw thread to move the valve flap, so it is unlikely that the valve will suddenly open or close, which makes the “water hammer” phenomenon less likely to occur.

The shut-off valve is suitable for transmitting liquid and gas medium under various pressure and temperature conditions, but it is not suitable for transmitting liquid that contains solid precipitation or precipitation of liquid crystals.

The shut-off valve is well suited for shut-off, regulation, and throttling. And it can be used in most medium systems. various Shut-off valves have been researched and developed to meet the needs of petrochemical, power, metallurgy, urban construction, chemical, and other sectors.

The post What are the Uses of Shut-off Valve? appeared first on Adamant Valves.

When the medium enters the valve from below the valve gate, the resistance the operating force needs to overcome is the friction between the valve stem and stuffing as well as the propulsion produced by the pressure of the medium. The force used to close the valve is bigger than the force used to open the valve, so the diameter of the valve needs to be big, otherwise, the valve stem will be bent.

There’re three types of connection methods: flange connection, threaded connection, and welded connection. Since the appearance of self-sealing valves, the flow direction of the medium of shut-off valves is changed to entering from above the valve gate.

In this case, under the pressure of the medium, the force used to close the valve is small while the force used to open the valve is big, so the diameter of the valve stem can be reduced accordingly. Meanwhile, under the influence of the medium, this type of valve is also more compact.

The opening and closing member of the shut-off valve is a plug-shaped sanitary valve gate. Its sealing surface is flat or sea-coned. The valve gate shuttles along the centerline of the valve seat. The movement of the valve stem includes an up-and-down rotating rod type, used for controlling the flow of various fluids like air, water, steam, corrosive media, mud, oil, liquid metal, and radioactive media.

Thus, this type of shut-off valve is very suitable for cutting off or regulating, or throttling.

This type of valve is very suitable for regulating the flow because the opening and closing distance of the valve stem is relatively short and has very reliable cutting-off functions and because the change in the valve seat is proportional to the distance of the valve gate.

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Its selection principle is:

1. In a pipeline or device of high temperature and high-pressure medium, it is suitable to use a sanitary shut-off valve. For example, it can be used in the high-temperature, high-pressure pipelines of thermal power plants, nuclear power plants, and petrochemical systems.

2. It can be used in pipelines that don’t have a strict requirement for flow resistance, namely, the occasion where there’s not much consideration for pressure loss.

3. For small-size valves, we can choose needle valve, meter valve, sampling valve, and pressure gauge valve.

4. It’s suitable to be used in pipelines where there’s flow regulation or pressure regulation, with the loose requirement for the regulating precision, and where the diameter of the pipeline is small.

5. High pressure angled shut-off valve and high pressure angled throttle whose nominal pressure is 16MPa and 32MPa respectively are suitable to be used in small chemical fertilizer and large chemical fertilizer in synthetic industrial production.

6. In the desalinization workshop of Alumina Bayer-method production and pipelines that are prone to coke, it’s preferable to use a direct flow type shut-off valve or direct flow type throttle that has a separate valve body, a removable valve seat, and a hard alloy sealing pair.

7. In water supply and heating projects of urban construction, for pipelines with small nominal diameter, shut-off valve, balance valve, and plunger valve can be used.

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The so-called “duplex stainless steel” is a kind of steel in which the ferrite phase and the austenite phase each accounts for half of the solid solution.

Usually, the small amount of phase is no less than 30%. Since there is a ferrite phase and austenite phase in the duplex stainless steel, it has relatively high strength and resistance to chloride stress corrosion associated with ferritic stainless steel, and excellent toughness and welding performance associated with austenitic stainless steel.

The features of all-forged duplex stainless steel shutoff valves:

1. The valve uses overall forging or forged welding structure and passes the non-destructive testing. It undergoes solid solution processing. The composition of the materials is fine. The product’s appearance is good.

2. The valve sealing is spray-welded hard alloy. Nickel-based solder powder, Stellite alloy, tungsten carbide, and other materials can be spray-welded. The hardness can be as high as HRC65. It has excellent wear and corrosion resistance, which improves the service life of the valve.

3. Due to the characteristics of duplex steel material itself, the valve has a strong resistance to hydrogen sulfide and chloride corrosion.

4. Considering the requirement on the strength of sanitary ball valve stem caused by increased opening and closing torque after the high-temperature deposition of the water-coal slurry medium, when designing duplex steel ball valve stems, 1740H deposition hardened stainless steel is used. This material can achieve a pretty high strength after the deposition hardening process, which meets the real-life requirements of valves.

5. All-forged duplex stainless steel shutoff valves use fixed balls. The force on the sealing pairs by the medium is significantly smaller than that of the floating ball, leading to decreased opening and closing torque.

The valve seat is designed to be a closed structure, which can effectively prevent the spring failure caused by deposition and fouling. The sealing ring uses flexible graphite or plastic alloy. The material has a very good sealing performance and high temperature-resistant performance. (flexible graphite can be up to 800 degrees Celsius and plastic alloy can reach 3000 degrees Celsius) The valve stem uses deposition hardened stainless steel.

The post The Features of Duplex Stainless Steel Shutoff Valves appeared first on Adamant Valves.

Sanitary shut-off valve is a kind of valve whose closing member (valve flap) moves along the centerline of the valve seat. Based on the type of movement of the valve flap, the change of valve seat opening is proportional to the valve flap stroke. Because the opening and closing stroke of the valve stem of this type of valve is relatively short, with a very reliable shut-off function, and because the change of valve seat opening is proportional to the valve flap stroke, which is very suitable for flow regulation, this type of valve is very suitable for shut-off, regulating, and throttling.

Once the valve flap of the shut-off valve is removed from the closing position, there is no longer contact between the valve seat and the sealing surface of the valve flap, so its sealing surface has very small mechanical wear. Therefore, it has an excellent sealing performance.

The disadvantage is that particles in a flowing medium may be stuck between sealing surfaces. However, this problem can be solved by turning the valve flap into a steel ball or porcelain ball. Because the valve seat and valve flap of most shut-off valves are easy to repair and replace, and because there’s no need to remove the entire valve from the pipeline when repairing or replacing sealing components, it’s very suitable for shut-off valves to be used in occasions where the valve and pipeline are welded.

Since the flow direction changes when the medium flows through this type of valve, the minimum flow resistance of the shut-off valve is also slightly higher than that of most other types of valves. However, the situation can be improved according to the structure of the valve body and the valve stem layout relative to the inlet and outlet channels.

Meanwhile, because the stroke between opening and closing of the valve flap of the shut-off valve is small, and because the sealing surface can sustain multiple times of opening and closing, it is very suitable for occasions where there’s a need for frequent opening and closing.

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The bellows-sealed shut-off valve is a highly specialized valve used to control flow rates in many industrial processing systems. It is suitable for various working condition pipelines in petroleum, chemical, pharmaceutical, fertilizer, electric power, and other industries to cut off or connect pipeline mediums.

The critical component of a bellows sealed sanitary shut-off valve—metal bellows—is welded at its lower end with the valve stem component and at the higher end with the connection plate, forming a metal barrier between the fluid medium and the atmosphere to ensure zero leakage of the valve stem. The valve flap and the sealing surface of the valve body undergo precision grinding and a 100% pressure test after assembly to achieve zero leakage. As an auxiliary sealing, the stuffing box remains on the bellows, increasing reliability and safety. The metal bellows of these high-pressure valves are multi-layered structures. Through hydraulic forming, these durable units can be guaranteed to perform at least ten thousand on/off full strokes at maximum pressure.

bellows sealed sanitary shutoff divert valves

Six Advantages of Bellows Sealed Shut Off Valves

The bellows seal design eliminates the shortcomings of rapid aging and easy leakage of common valve stem packing seals. It improves energy efficiency, increases the safety of production equipment, reduces maintenance costs and frequency, and provides more outstanding cleanliness and safety, making these valves useful in many industrial working environments.

1. Double sealing design

Sealed by the bellows and packing, if the bellows fail, the stem packing will remain intact and leak-free.

2. Structurally sound

The robust structural integrity provides reliable sealing and excellent leakproof performance.

3. Zero fluid loss

Leak-free performance results in no fluid loss, which reduces energy consumption, promotes environmental friendliness, and improves plant equipment safety for employees.

4. Extra durability

The sealing surface is coated with co-based cemented carbide for wear resistance, corrosion resistance, friction resistance, long service life, reduced maintenance time, and reduced operating costs.

5. Leak-free performance

The sturdy and durable bellows seal design ensures zero leakage of the valve stem and provides maintenance-free conditions.

6. Corrosion & friction resistance

The stop valve stem is quenched and tempered, and the surface is nitridated for superior anti-corrosion and anti-friction properties.

Conclusion — Sanitary Shutoff Valves

These sanitary shutoff valves are pneumatically or manually operated and offered in a wide variety of body configurations. When stopping or diverting flow in a processing system, this series single-seat valve line provides a flexible and reliable solution.

Adamant Valves is a trusted supplier of bellows sealed shutoff valves. We can provide a custom build, or you can choose from our existing inventory of body and disc materials such as AISI 304, AISI 316L, 304L, and 316 materials. Automated or manual operation valves are available according to your needs. 

Thank you for reading our article. We hope it can help you better understand the advantages of bellows sealed shut-off valves. If you want to learn more about sanitary valves, we would like to advise you to visit Adamant Valves for more information.

The post Six Advantages of Bellows Sealed Shutoff Valves appeared first on Adamant Valves.

Sanitary shutoff valves play a critical role in almost any fluid, gas, or slurry system. We depend on shutoff valves to provide dependable on and off functionality and specific flow rates in residential, commercial, and institutional applications. While many are utilized routinely, they can also provide safety measures in emergency situations to prevent further outflow. This is why it’s so important to pressure test a sanitary shutoff valve.

The strength test for sanitary shut-off valves is very similar to the pressure testing methods for diaphragm valves. To pressure test a sanitary shutoff valve, we usually put assembled valves in the pressure testing rack, open the valve flap, pour in the medium to the specified value, and check for any leakage at the valve body and valve cover. The strength test can also be conducted individually.

how to pressure test a shutoff valve

For the sealing performance test, place the valve stem of the shut-off valve in a vertical position. Open the valve flap and introduce the fluid or gas medium to the specified value from the bottom of the valve flap. Check the stuffing and gasket. Close the valve flap after the valve is qualified, and open the other end to check for any leakage.

If both the strength test and sealing performance test need to be conducted, we can first conduct the strength test, then lower the pressure to the specified value of the sealing performance test. Check the stuffing and gasket. Then close the valve flap, and open the outlet to check if there is leakage at the sealing surface.

Pressure test method of shut-off valve and throttle valve

For the strength test of the shut-off valve and throttle valve, the assembled valve is usually placed in the pressure test frame, the valve disc is opened, the medium is injected to the specified value, and the body and bonnet are checked for sweating and leakage. The strength test can also be carried out on a single piece.

The shut-off valve is used for the sealing tests. During the test, the valve stem of the stop valve is in a vertical position, the valve disc is opened, and the medium is introduced from the lower end of the valve disc to the specified value. Check the packing and gasket. After passing, close the disc and open the other end to check for leakage. If the valve strength and sealing test are to be done, the strength test can be done first and then depressurized to the specified value of the sealing test. Check the packing and gasket, then close the valve disc and open the outlet end to check whether the sealing surface leaks.

How does a shutoff valve work?

Shut-off valves rely on the pressure of the valve stem to force the sealing surfaces of the valve flap and the valve seat fit tightly together and prevents the medium from flowing through.

Sanitary shut-off valves only allow one-way flow of the medium and require directional installation. Structurally, they are usually longer than gate valves and they offer higher fluid resistance. However, the sealing reliability is not great for extended durations, which is why they are normally used for emergency shutdown situations. There are three types of shut-off valves: straight-through, right angle, and straight-flow oblique type.

What is the purpose of a shutoff valve?

The shutoff valve is one of the most widely used types of valves and plays the important role of cutting off and throttling the medium in the pipeline. Shutoff valves are often used for quick system shutdown in emergency situations. Its biggest advantage, and the reason why it is so popular, is the low-friction performance of sealing surfaces throughout the opening and closing process. With a narrow opening and durable design, they are easy to manufacture, install, and maintain. It is not only suitable for medium and low-pressure applications but also works reliably in high-pressure systems.

Conclusion

One key feature of shutoff valves is their plug-in disc which is flat or conical on the sealing surface. The disc moves along the centerline of the valve seat in a straight line. It can be used to control the flow of air, water, steam, various corrosive media, mud, oil, liquid metal, and radioactive media. This type of shut-off valve is very suitable for cut-off, regulation, and throttling. The opening or closing stroke of the valve stem is relatively short, and it has a very reliable cut-off function. Because the change of the valve seat opening is directly proportional to the stroke of the valve disc, it is very suitable for regulating the flow of fluids and gases.

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A shut-off valve is a valve whose closing member moves along the centerline of the valve seat. According to the type of movement of the valve flap, the change of diameter of the valve seat is proportionate to the stroke of the valve flap. Because the opening and closing stroke of the valve stem is relatively short, with a very reliable shut-off function, and because the change of diameter of the valve seat is proportionate to the stroke of valve flap, which is very suitable for flow regulation, this type of sanitary shut-off valve is very suitable for shutting off, regulating or throttling.

The principle of selecting shut-off valves:

1. Shut-off valves should be used on pipelines or devices of high temperature and pressure media, such as thermal power plants, nuclear power plants, high temperature and pressure pipelines of petrochemical systems.

2. Pipelines that aren’t strict about fluid resistance. That is the place where the pressure loss is not a big concern.

3. Needle valve, instrument valve, sampling valve, and pressure gauge valve can be used for small valves.

4. Pipelines where there are flow regulation and pressure regulation, with few requirements for regulation accuracy, and the pipeline diameter is small.

5. High pressure angled shut-off valve and high pressure angled throttle should be used for small chemical fertilizer and large chemical fertilizer in synthetic industrial production.

6. In de silicon workshops and pipelines that are easy to coke, a DC-type electric shut-off valve or DC-type throttle that has a separate valve body, a removable valve seat, and carbide seal should be used.

7. In water supply and heating projects of urban construction, shut-off valve, balance valve or plunger valve can be used for pipelines that have a relatively small nominal diameter.

The post The Principle of Selecting Shut-off Valve appeared first on Adamant Valves.

A needle sanitary shut-off valve is a small gauge globe valve that opens and closes and precisely controls flow in the instrumentation piping system. They are mainly power station instrumentation series, oilfield series, and American standard series.

2. Low-temperature sanitary shut-off valve

Low-temperature globe valves are usually globe valves with operating temperatures below -110 ° C and are widely used in LNG, liquefied petroleum gas, and other cryogenic industries. From 2008 it can be made for the temperature of -196 ℃ cut-off valve, all parts of liquid nitrogen pretreatment at low temperature, completely avoid the use of seal deformation leaks.

3. Plunger sanitary shut-off valve

The sealing surface of a plunger sanitary shut-off valve is a radial seal structure. This valve has two elastic sealing rings that wrap over the polished plunger. The valve body and bonnet connection bolts apply a load on the bonnet, compressing the elastomeric seal around the plunger to seal.

4. Insulation sanitary pinch valve

The design of an insulation sanitary pinch valve uses an external heat source in the outside of the globe valve cycle heating, effectively preventing the media through the shut-off valve temperature loss, to ensure the temperature of the medium.

Next part

The post Sanitary Shut-off Valve Applications (1) appeared first on Adamant Valves.

The high-pressure shut-off valve is mainly used in industries that have high requirements for pressure. The conventional connection method is welding and threading. The high-pressure shut-off valve is mainly used in the chemical and pharmaceutical fields. Since it’s welded, it’s not convenient for replacement. It’s mainly suitable for occasions where the repair is not very frequent and the wear ratio is relatively low.

Sanitary shut-off valve is a kind of valve whose closing member (valve flap) moves along the centerline of the valve seat. According to this type of movement of the valve flap, the change in the opening of the valve seat is proportional to the stroke of the valve flap. Because the opening and closing stroke of the valve stem of this type of valve is relatively short and the shut-off function is very reliable, and because the change in the opening of the valve seat is proportional to the stroke of valve flap, which is very suitable for the regulation of the flow, this type of valve is very suitable for shut-off, regulation, and throttling.

The most prominent advantages of shut-off valve are:

1. During the process of opening and closing, as the friction between the valve flap and the sealing surface of the valve body is smaller than that of the gate valve, it’s very wearable.

2. The opening height is usually only one-fourth of the diameter of the valve seat passage, which is much smaller than that of the gate valve.

3. Usually there’s only one sealing surface on the valve body and valve flap, so the manufacturing technique is good and it’s easy to repair.

Meanwhile, the disadvantages of shut-off valves can’t be ignored. Its main disadvantage is the big flow resistance coefficient, which causes pressure loss. And in hydraulic devices, this kind of pressure loss is particularly obvious.

Conclusion

Thank you for reading our article and we hope it can help you better understand the advantages of ultra high-pressure shut-off valves. If you want to learn more about ultra high-pressure shut-off valves, we would like to advise you to visit Adamant Valve homepage for more information.

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