Brass valves can be divided into many types according to their structure and characteristics. Different types have their own advantages and disadvantages. When selecting and using valves, we need to fully understand this information so that we can make better choices and ensure that Efficient and safe use of pipeline valves. Today we will learn the advantages and disadvantages of various brass valves.
Table of Contents
1. Brass ball valve
2. Brass gate valve
3. Brass butterfly valve
4. Brass globe valve
5. Brass angle valve
6. Brass safety valve
7. Brass pressure reducing valve
8. Brass check valve
9. Conclusion
1. Brass ball valve
It is evolved from the brass angle valve. Its opening and closing part is a sphere, and the sphere is rotated 90° around the axis of the valve stem to achieve the purpose of opening and closing. Brass ball valves are mainly used for cutting, distributing and changing the flow direction of media on pipelines. Brass ball valves designed with V-shaped openings also have good flow regulation functions.
Advantages
1. Has the lowest flow resistance (actually 0);
2. Because it will not get stuck during work (when there is no lubricant), it can be reliably used in corrosive media and low boiling point liquids;
3. In a wide range of pressure and temperature, it can achieve complete sealing;
4. It can realize rapid opening and closing, and the opening and closing time of some structures is only 0.05~0.1s, so as to ensure that it can be used in the automation system of the test bench. When the brass valve is opened and closed quickly, the operation has no impact;
5. The spherical closure can be automatically positioned at the boundary position;
6. The working medium is reliably sealed on both sides;
7. When fully open and fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, so the medium passing through the brass valve at high speed will not cause erosion of the sealing surface;
8. Compact structure and light weight, it can be considered as the most reasonable brass valve structure for low temperature medium system;
9. The valve body is symmetrical, especially the welded valve body structure, which can well withstand the stress from the pipeline;
10. The closing part can withstand the high pressure difference when closing. ⑾ Brass ball valve with fully welded valve body can be directly buried in the ground, so that the brass valve internals are not corroded, and the maximum service life can reach 30 years. It is the most ideal brass valve for oil and natural gas pipelines.
Disadvantages
1. Because the most important valve seat sealing ring material of brass ball valve is polytetrafluoroethylene, it is inert to almost all chemical substances, and has a small friction coefficient, stable performance, not easy to age, wide temperature range and sealing Comprehensive features of excellent performance. But the physical properties of PTFE, including high coefficient of expansion, susceptibility to cold flow, and poor thermal conductivity, require that seat seal designs must be built around these properties. Therefore, when the sealing material becomes hard, the reliability of the sealing is damaged. Moreover, PTFE has a low temperature resistance grade and can only be used below 180°C. Above this temperature, the sealing material will degrade. In the case of long-term use, it is generally not used at 120 °C.
2. Its adjustment performance is worse than brass globe valve, especially pneumatic valve (or electric valve).
2. Brass gate valve
Brass gate valve refers to a brass valve whose closing member (gate) moves in the vertical direction of the channel axis. It is mainly used to cut off the medium on the pipeline, that is, fully open or fully closed. Generally, brass gate valves cannot be used to regulate flow. It can be applied to low temperature or high temperature and high pressure, and can be used according to different materials of brass valves. However, brass gate valves are generally not used in pipelines for conveying mud and other media.
Advantages
1. The fluid resistance is small;
2. The torque required for opening and closing is small;
3. It can be used on the ring network pipeline where the medium flows in two directions, that is to say, the flow direction of the medium is not restricted;
4. When fully open, the sealing surface is less eroded by the working medium than the brass globe valve;
5. The body structure is relatively simple, and the manufacturing process is better;
6. The length of the structure is relatively short.
Disadvantages
1. The external dimension and opening height are large, and the space required for installation is also large;
2. During the opening and closing process, the sealing surface is relatively rubbed, and the friction loss is relatively large, and even at high temperature, it is easy to cause scratches;
3. Generally, brass gate valves have two sealing surfaces, which adds some difficulties to processing, grinding and maintenance,
4. The opening and closing time is long.
3. Brass butterfly valve
Brass butterfly valve is a kind of brass valve that uses a disc type opening and closing member to reciprocate about 90° to open, close and adjust the fluid channel.
Advantages
1. Simple structure, small size, light weight, and less consumables, do not use in large-diameter brass valves,
2. Quick opening and closing, small flow resistance,
3. It can be used for medium with suspended solid particles, and can also be used for powdery and granular media according to the strength of the sealing surface. It can be used for two-way opening and closing and adjustment of ventilation and dust removal pipelines, and is widely used in gas pipelines and waterways of metallurgy, light industry, electric power, and petrochemical systems.
Disadvantages
1. The flow adjustment range is not large, when the opening reaches 30%, the flow will enter more than 95%,
2. Due to the limitation of the structure and sealing material of brass butterfly valve, it is not suitable to be used in high temperature and high pressure pipeline system. The general working temperature is below 300℃ and below PN40,
3. The sealing performance is poorer than that of brass ball valve and brass globe valve, so it is used in places where the sealing requirements are not very high.
4. Brass globe valve
Brass globe valve refers to the brass valve whose closing member (valve) moves along the centerline of the valve seat. According to this moving form of the valve disc, the change of the valve seat port is proportional to the valve disc stroke. Because the valve stem of this type of brass valve has a relatively short opening or closing stroke, and has a very reliable cut-off function, and because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for flow regulation. Therefore, this type of brass valve is very adaptable for shut-off or regulation and throttling.
Advantages
1. 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 brass gate valve, so it is wear-resistant.
2. The opening height is generally only 1/4 of the valve seat channel, so it is much smaller than the brass gate valve,
3. Usually there is only one sealing surface on the valve body and valve disc, so the manufacturing process is better and it is easy to maintain,
4. Because its filler is generally a mixture of asbestos and graphite, its temperature resistance grade is higher. General steam brass valves use brass globe valves.
Disadvantages
1. Due to the change in the flow direction of the medium through the brass valve, the minimum flow resistance of the brass globe valve is also higher than that of most other types of brass valves,
2. Due to the longer stroke, the opening speed is slower than that of the brass ball valve.
5. Brass angle valve
Brass angel valve refers to a rotary valve whose closing member is in the shape of a plunger. Through 90° rotation, the channel port on the valve plug is connected or separated from the channel port on the valve body to realize opening or closing. Copper valve. The shape of the valve plug can be cylindrical or conical. The principle is basically similar to that of the brass ball valve. The brass ball valve is developed on the basis of the brass angle valve. It is mainly used in oilfield exploitation and petrochemical industry.
6. Brass safety valve
It is used as an overpressure protection device on a pressurized container, equipment or pipeline. When the pressure in the equipment, container or pipeline rises beyond the allowable value, the brass valve opens automatically, and then discharges in full to prevent the equipment, container or pipeline and the pressure from continuing to rise; when the pressure drops to the specified value, the yellow Copper valves should automatically close in time to protect the safe operation of equipment, containers or pipelines.
7. Brass pressure reducing valve
It is a brass valve that reduces the inlet pressure to a certain required outlet pressure through adjustment, and relies on the energy of the medium itself to automatically keep the outlet pressure stable.
8. Brass check valve
Brass check valve also known as reverse flow valve, check valve, back pressure valve and one-way valve. These brass valves are automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, and belong to an automatic brass valve. Brass check valve is used in the pipeline system, its main function is to prevent the backflow of the medium, prevent the reverse rotation of the pump and the driving motor, and discharge the medium in the container. Check valves can also be used on pipelines that supply supply to auxiliary systems where the pressure may rise above the system pressure. They can be mainly divided into swing type (rotating according to the center of gravity) and lifting type (moving along the axis).
Here below is a professional introductive video for different brass valves for your reference:
Video: What's better - ball valve vs gate valve vs stop valve (source: youtube.com)
9. Conclusion
Here comes to the end of comprehensive comparison to different types of brass valves, which will be helpful when selecting and using valves, we need to fully understand this information so that we can make better choices and ensure that Efficient and safe use of pipeline valves.
NAFCO is one of most specialized brass valve manufacturers in China, with over 20 global service experience.
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