It is composed of valve body, valve stem, butterfly plate and sealing ring. The valve body is usually cylindrical, providing space for the rotation of the butterfly plate; the valve stem is connected to the butterfly plate to transmit the rotational power; the sealing ring is installed on the valve body or butterfly plate to seal and prevent fluid leakage.
The butterfly valve has a simple and compact structure, small size, light weight. it is easy to install and disassemble, greatly reduces the difficulty and cost of construction and maintenance.
The ball valve has excellent sealing performance,it can effectively prevent fluid leakage in both low-pressure and high-pressure environments. This is benefit for the close contact between the ball and the seal and the good processing accuracy.
At the same time, the ball valve has low fluid resistance, because when the valve is opened, the channel is straight-through, the fluid can flow through without obstruction, and the pressure loss is extremely small,In particularly suitable for occasions with strict requirements on fluid resistance.
In addition, the ball valve has a long service life. Due to the small wear of the ball and seal, it can operate stably for a long time under normal use and maintenance.
Flange connection is one of the commonly used connection methods for butterfly valves and ball valves.
Since the butterfly valve has a compact structure and small size, the flange size used with the butterfly valve is relatively small.
During installation, the flange of the butterfly valve is fixed to the pipe flange by bolts, and a sealing gasket is installed in the middle to ensure the sealing of the connection.
When the ball valve is connected by flange, the flange structure is relatively thick. The ball and valve body of the ball valve are heavy, and need a stronger flange to support and fix. The flange of the ball valve is usually larger in size and thickness to ensure stable operation under high pressure and large diameter conditions.
Compared with the butterfly valve, the flange connection of the ball valve is more stable, but it is relatively difficult to install and disassemble, and requires more space.
Wafer connection is a unique connection method for butterfly valves, It is generally not used for ball valves. There are no flanges on both sides of the valve body of the wafer butterfly valve. Instead, the butterfly valve is clamped in the middle by two pipe flanges and fastened with bolts.
The biggest advantage of this connection method is that it saves space. Since here is not need additional flange space, the wafer butterfly valve can be installed in a pipeline system with a small space.
At the same time, the butterfly valve with wafer connection is light in weight and easy to install, which can effectively reduce the installation cost and construction difficulty.
Welding connection is more common in the application of ball valves. The ball valve with welding connection directly welds the valve body and the pipeline together to form a whole, which has extremely high connection strength and sealing.
This connection method is suitable for high temperature, high pressure, flammable and explosive working conditions with extremely high sealing requirements.
Once the welded ball valve is installed, there is almost no risk of leakage and it can operate stably for a long time.
However, the installation cost of welding connection is high, and it is more difficult to repair and replace. It requires cutting the pipeline, which causes greater damage to the pipeline system.
The maintenance cost and time cost are relatively high. In contrast, butterfly valves are rarely connected by welding due to the characteristics of structure and material, unless it is required by some special working conditions.
In small-diameter pipelines, both butterfly valves and ball valves may use threaded connections, but there are also differences between this two type valve.
When butterfly valves use threaded connections, they are usually suitable for some low-pressure and small-flow occasions. Their threaded structure is relatively simple and easy to install and disassemble, but their sealing performance is relatively weak, they are prone to leakage under high-pressure conditions.
The threaded connection of ball valves is suitable for small-diameter, medium- and low-pressure pipeline systems. Compared with butterfly valves, the threaded connection of ball valves performs better in sealing and reliability, but the cost will be higher.
Butterfly valves have obvious advantages in cost. They have a simple structure, fewer parts, and a relatively easy production process, so butterfly valves manufacturing cost is lower. Both the raw material cost and the processing cost are lower than ball valves cost.
In small engineering projects or occasions with strict cost control, the low price of butterfly valves can effectively reduce the project budget. Butterfly valves are easy to install, and the required installation materials and labor costs are relatively small, further saving overall costs.
In contrast, due to the complex structure of ball valves, high processing precision requirements for the ball and seals, high raw material costs and manufacturing costs, the market price of ball valves is generally higher than butterfly valves.
The butterfly valve has small size and light in weight, more flexible and convenient during installation. The butterfly valve has various connection methods, especially the clamp connection, which can be quickly installed in a small space, it is particularly suitable for renovation projects or occasions in limited space.
The ball valve with large weight and volume, requires professional lifting equipment during installation, and need high technical requirements for installation space and construction personnel.
In some complex installation environments, the installation of ball valves may be restricted, while butterfly valves can easily cope with it.
The opening and closing process of butterfly valves only requires rotating the valve stem 90°. The operation is simple and fast, the valve can be opened and closed in a short time. This fast opening and closing feature makes butterfly valves have obvious advantages in occasions where fluids need to be cut off urgently.
In contrast, although ball valves are also opened and closed by rotating the ball, due to their relatively complex structure and large moment of inertia of the ball, in some cases, the opening and closing speed may not be as fast as butterfly valves. Especially in large-diameter ball valves, the time and torque required for opening and closing will increase, affecting their response speed.
The ball valve has good sealing performance, and the close fit between the ball and the seal makes it almost possible to achieve zero leakage in the closed state. Whether in low-pressure or high-pressure environments, ball valves can effectively prevent fluid leakage,so the ball valve widely used in natural gas transportation and petrochemicals industries with extremely high sealing requirements.
Due to the butterfly plate structural characteristics in the valve body, the sealing performance will be affected to a certain extent under high pressure difference conditions, and exit certain degree of leakage risk.
When the ball valve is open, the channel is straight-through, the fluid can flow through without obstruction, with minimal pressure loss. Ball valves are very suitable for strict fluid resistance requirements occasions, such as long-distance pipeline transportation, large-scale water supply and drainage systems, etc. In these systems, low resistance can reduce energy loss and improve transportation efficiency.
However, since the butterfly plate of a butterfly valve occupies a certain space in the valve body, it will generate greater resistance when the fluid flows through, especially when the butterfly plate is in a partially open state, the resistance is more obvious, which will not only increase energy consumption, but also may affect the operating efficiency of the system.
During the opening and closing process of the ball valve, the relative movement between the ball and the seal is small, the contact area is large, and the wear is uniform. Therefore, the ball and seal of the ball valve are less worn, and under normal use and maintenance, it can operate stably for a long time and has a long service life.
During the long-term use of the butterfly valve, the friction between the butterfly plate and the sealing ring is more frequent, especially under frequent opening and closing conditions, the sealing ring is easy to wear, resulting in sealing performance decrease, the sealing ring needs to be replaced regularly, increases maintenance costs and workload.
Due to the ball valve solid structure and good sealing performance, ball valves can adapt to a wider range of pressures and can operate stably from low pressure to high pressure conditions.
Due to structural and material limitations, butterfly valves are usually only suitable for medium and low pressure conditions. Under high pressure conditions, the butterfly plate and sealing ring of the butterfly valve are easily damaged, affecting the normal use and sealing performance of the valve.
the ball valve applicable media is very wide, and it can be used for almost all kinds of different media, including water, oil, gas and some corrosive media. The diversity of its materials and sealing materials enables the ball valve to be selected and customized according to the characteristics of different media.
Although the butterfly valve can also be applied to a variety of media, its use may be limited in some special media, such as high viscosity media, media containing particulate impurities, etc. The butterfly plate is easily worn in these media, affecting the service life and sealing performance of the valve.
In terms of working conditions, butterfly valves are more suitable for medium and low pressure, large-diameter pipeline systems, such as urban water supply and drainage networks, ventilation and air conditioning systems, etc.
In these systems, the fast opening and closing and light and flexible characteristics of butterfly valves can be fully utilized, the medium and low pressure working conditions have relatively low requirements for the sealing performance,butterfly valves can meet the use requirements.
In addition, in some occasions where there are restrictions on installation space, the clamp connection method of butterfly valves also has unique advantages.
In terms of applicable media, butterfly valves are mainly suitable for clean media such as water and air,and some less corrosive media. For media containing particulate impurities or high viscosity, the use of butterfly valves needs to be cautious, because these media are easy to cause wear on the butterfly plate and sealing ring, affecting the performance and service life of the valve.
Ball valves are suitable for a wider range of working conditions, especially in high pressure, high temperature, flammable and explosive, toxic and harmful places with extremely high safety and sealing requirements, such as petrochemical, natural gas transportation, power industry, etc.
The high sealing performance and pressure resistance of ball valves can ensure stable operation under harsh working conditions, ensure the safety of the system. At the same time, ball valves are more advantageous than butterfly valves in fluid resistance strict requirements and precise flow control occasion.
Due to its good sealing performance and structural characteristics, ball valves are more suitable for a wider range of media. In addition to common water, oil, and gas, they can also be used for various corrosive media, such as acid, alkali and other chemical media.
Because the ball valve straight-through channel design of the ball valve reduces the risk of blockage and wear of the medium inside the valve, it can also work normally when handling media containing particulate impurities or high viscosity.
In summary, butterfly valves and ball valves have their own advantages and disadvantages, and play their respective roles under different working conditions and media conditions.
When choosing a valve, you need to consider multiple factors such as cost, installation, performance, applicable working conditions and media to make the most suitable decision.
