How does a globe valve work? Urgent. How does a globe valve work?

How does a globe valve work? Urgent.

This article analyzes the working principle of globe valves in detail. If you think it is helpful to you, please raise your hand and give the American Weidun VTON valve stop valve a thumbs up!

The opening and closing parts of the stop valve (globe valve) are plug-shaped discs, which are flat or sea cone surfaces on the seal, and the disc moves in a straight line along the center line of the valve seat. The movement form of the valve stem, (common name: dark rod), there are also lifting and rotating rod types, which can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media.

As a result, this type of shut-off valve valve is ideal for shut-off or regulation and throttling. This type of valve is very suitable for regulating the flow rate because the stem opening or closing stroke is relatively short, and because it has a very reliable shut-off function, and because the change of the seat port is proportional to the stroke of the disc.

Shut-off valves can be used in most material step system software. It has developed various forms of globe valves for various main purposes in petrochemical industry, electric power engineering, metallurgical industry, urban construction, chemical plants and other units.

The application of globe valve is extremely extensive, but because the opening and closing torque is very large, the structure length is long, the general nominal pipe diameter is limited to DN250m or less, and it also reaches DN400mm, but it is necessary to pay attention to the direction of the inlet and outlet when using. In general, most of the shut-off valve materials below DN15OMM are injected directly below the piston valve, while most of the shut-off valve materials above DN250m are injected from the top of the piston valve. It is fully considered to be triggered by the shut-off torque of the gate valve.

In order to reduce the torque of opening or closing, the shut-off valve above 250m is generally equipped with an internal bypass valve or an external intake valve.

Shut-off valves can also be used for flow regulation.

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following are the top ten domestic first-line valve brand manufacturers in 2022-2023, but for reference only: Suzhou Neway Valve Co., Ltd., Shanghai Guanlong Valve Machinery, Shanghai Qizhong Valve Manufacturing.

Sanhua, Suyan, Shentong, Suvalve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

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 fit tightly to prevent the flow of medium.

Answer: The opening and closing parts of the gate valve are the gate plate, the direction of movement of the gate plate is perpendicular to the direction of the fluid, and the gate valve can only be fully opened and closed, and cannot be adjusted and throttled. The ram has two sealing surfaces, and the most commonly used mode gate valve has two sealing surfaces forming a wedge, and the wedge angle varies with the valve parameters, usually 5°, and 2°52 when the medium temperature is not high'。The gate plate of the wedge gate valve can be made into a whole, which is called a rigid gate; It can also be made into a ram that can produce a slight amount of deformation to improve its manufacturability and make up for the deviation of the sealing surface angle in the processing process, which is called an elastic ram.

When the gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, the sealing surface of the ram plate is pressed to the valve seat on the other side by relying on the medium pressure to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves are forcibly sealed, that is, when the valve is closed, the ram should be forcibly pressed against the valve seat by external force to ensure the tightness of the sealing surface. If the gate plate of the gate valve moves in a straight line with the valve stem, it is called the lifting rod gate valve, also known as the open rod gate valve.

Usually there is a trapezoidal thread on the lifting rod, which changes the rotary motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, the operating torque into operating thrust. When the valve is opened, when the ram lift height is equal to 1:1 times the valve diameter, the flow of the fluid is completely unobstructed, but this position cannot be monitored during operation.

In actual use, it is marked by the apex of the valve stem, that is, the position that cannot be opened, as its fully open position. In order to account for the lock-up phenomenon of temperature changes, it is usually rewound back to the apex position and then reverses 1 2 1 turns as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the ram, that is, the stroke.

Some gate valves, the stem nut is located on the gate, and the handwheel rotates to drive the valve stem to rotate, and the gate plate is lifted, this kind of valve is called the rotary rod gate valve, or called the dark rod gate valve.

Electric globe valve and flange gate valve are the same type of valves, composed of electric actuator or pneumatic actuator and globe valve, the difference is that its closing part is a valve body, and the valve body rotates around the center line of the valve body to achieve opening and closing.

Gate valves are mainly used in pipelines to cut off, distribute and change the flow direction of the medium. The two-piece ball valve and the three-piece ball valve are a new type of valves that have been widely used in recent years.

Electric globe valve, also known as electric shut-off door, is the most widely used valve, and electric ball valve is different, it is widely popular, because the friction between the sealing surfaces in the opening and closing process is small, relatively durable, the opening height is not large, easy to manufacture, easy to maintain, not only suitable for low pressure, but also suitable for high pressure.

The closing principle of the electric globe valve is to rotate the valve lever by electric thrust to make the sealing surface of the valve disc and the sealing surface of the valve seat fit tightly to prevent the flow of medium.

The electric shut-off valve allows only one-way flow of media and is directional when installed. The structural length of the globe valve is greater than that of the gate valve, and the fluid resistance is large, and the sealing reliability is not strong during long-term operation.

The globe valve is a forced seal valve, so when the valve is closed, pressure must be applied to the disc to force the sealing surface not to leak. When the medium enters the valve six from the bottom of the valve disc, the resistance that the operating force needs to overcome is the friction force of the valve stem and the packing material and the thrust generated by the pressure of the medium, and the force of closing the valve is greater than the force of opening the valve, so the diameter of the valve stem should be larger, otherwise the fault of the top bend of the valve stem will occur. In recent years, after the emergence of the self-sealing valve, the medium flow direction of the globe valve has been changed from the top of the disc to enter the valve cavity, at this time, under the action of medium pressure, the force of closing the valve is small, and the force of opening the valve is large, and the diameter of the valve stem can be reduced accordingly.

At the same time, under the action of the medium, this form of valve is also tighter. China's valve "three to give" has stipulated that the flow direction of the globe valve is all top-down.