Valves are control components in fluid delivery systems, with functions such as shutoff, regulation, diversion, backflow prevention, pressure stabilization, diversion or overflow pressure relief. Valves used in fluid control systems come in a wide variety of varieties and specifications, from the simplest shutoff valves to the various valves used in extremely complex automatic control systems. Valves 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.
Classification and use of butterfly valves:
1. Butterfly valves are also called butterfly valves. As the name suggests, its key components are like butterflies facing the wind and rotating freely.
2. The disc of a butterfly valve is a disc that rotates around an axis in the valve seat. The size of the rotation angle is the opening and closing degree of the valve.
3. Butterfly valves are lightweight and save materials compared to other valves. They have a simple structure, open and close quickly, can be used for cutting off and throttling, have low fluid resistance, and are labor-saving to operate. Butterfly valves can be made into large diameters. Where butterfly valves can be used, it is best not to use gate valves, because butterfly valves are more economical than gate valves and have better adjustability. At present, butterfly valves are widely used in hot water pipelines.
Classification and use of ball valves:
1. The working principle of ball valves is to make the valve open or closed by rotating the valve ring. Ball valves are light and small in size, can be made into large diameters, have reliable sealing, simple structure, and are easy to maintain. The sealing surface and the spherical surface are often in a closed state and are not easily eroded by the medium. They are widely used in various industries.
2. Ball valves are divided into two categories, one is floating ball type and the other is fixed ball type.
Classification and use of gate valves:
Gate valves, also called gate valves, are widely used valves.
1. Its closing principle is that the gate sealing surface and the valve seat sealing surface are highly smooth, flat and consistent, and fit each other, which can prevent the medium from flowing through, and rely on the top mold, spring or gate mold shape to enhance the sealing effect. It mainly plays a cutting role in the pipeline.
2. Its advantages are: small fluid resistance, easy opening and closing, can be used in the case of two-way flow of the medium, no directionality, the sealing surface is not easy to erode when fully opened, and the structure length is short. It is not only suitable for small valves, but also for large valves.
3. Gate valves are divided into two categories according to the valve stem thread, one is the rising stem type, and the other is the concealed stem type.
4. According to the gate structure, it is also divided into two categories, one is parallel and the other is mode.
Classification and use of globe valves:
Globe valve, is the most widely used valve. It is popular because of the small friction between the sealing surfaces during opening and closing, relatively durable, small opening height, easy manufacturing, convenient maintenance, and is suitable not only for medium and low pressure, but also for high pressure.
1. Its closing principle is to rely on the valve stem pressure to make the valve disc sealing surface and the valve seat sealing surface fit tightly to prevent the flow of medium.
2. The globe valve only allows the medium to flow in one direction and has directionality when installed. Its structural length is greater than that of the gate valve, and the fluid resistance is large. When it is running for a long time, the sealing reliability is not strong.
3. globe valves are divided into three categories: straight-through, right-angle and direct current oblique stop valves.
Check valve classification and uses:
1. Check valve is a valve that automatically opens and closes by the force of the fluid itself. Its function is to prevent the medium from flowing back. It has many names, such as non-return valve, one-way valve, one-way valve, etc. It can be divided into two categories according to its structure.
(1) Lifting type: The valve disc moves along the vertical center line of the valve body. There are two types of this type of check valve: one is horizontal, installed in horizontal pipes, and the valve body shape is similar to that of a stop valve; the other is vertical, installed in vertical pipes.
(2) Swing type: The valve disc rotates around the pin outside the seat. This type of valve has single disc, double disc and multi-disc, but the principle is the same.
2. The water suction bottom valve of the water pump suction pipe is a deformation of the check valve. Its structure is the same as the above two types of check valves, except that its lower end is open to allow water to enter.
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