Among the various types of valves, ball valves and gate valves are the two most widely used in the industrial sector. Each of them has its own advantages: The most prominent feature of the ball valve is “rapid opening and closing”, which is particularly suitable for scenarios that require frequent switching of the on-off state; while the gate valve excels in precisely regulating the flow and handling high-pressure conditions.
However, industrial scenarios are complex and diverse, and the requirements of different systems vary greatly. How to select the appropriate valve to precisely match the actual needs and avoid cost waste or safety hazards caused by incorrect selection has become a core issue that many enterprises and engineering technicians must carefully consider.
The core structure of a ball valve is not complicated. It mainly consists of a ball, a valve seat, a valve stem, a valve body, and a driving device (commonly manual, electric or pneumatic).
Among these components, the ball is the “core component” that controls the flow of the medium – the center of the ball has a hole approximately the same diameter as the pipeline. When the valve stem rotates, it can drive the ball to rotate together. The valve seat is usually made of elastic materials (such as polytetrafluoroethylene soft seal) or metal materials (such as stainless steel hard seal), closely adhering to the surface of the ball to ensure a good sealing effect and prevent medium leakage.
As for the valve stem, its function is to transmit the driving force, and it also has a sealing structure on its own, which can prevent the medium from leaking through the gap between the valve stem and the valve body.
From the perspective of the working principle, the operation of a ball valve is very intuitive: by rotating the valve stem to drive the ball to rotate 90 degrees, the control of the medium flow can be achieved. When the hole on the ball is aligned with the axis of the pipeline, the medium can smoothly pass through the hole, and at this time, the valve is in the fully open state; when the ball rotates 90 degrees, the hole is perpendicular to the axis of the pipeline, and the surface of the ball will block the medium channel, and the valve is in the closed state.
This “90-degree rotation for opening and closing” method gives the ball valve the core advantage of “fast opening and closing” – compared to many other valves, its opening and closing time is extremely short, usually only taking a few seconds to complete the operation. Therefore, in scenarios where frequent switching or rapid cutting off of the medium is required, ball valves are particularly suitable. In addition, this structure can also reduce the retention time of the medium inside the valve and lower the risk of impurities accumulating in the valve.
The core components of a gate valve include a gate plate, a valve seat, a valve stem, a handwheel (or electric/pneumatic actuator), and a valve body. Among them, the gate plate is the key to controlling the flow rate. According to its structure, it is mainly divided into wedge gate plates and parallel gate plates.
Wedge gate plates are more suitable for high-pressure scenarios—they can achieve a good sealing effect by fitting tightly with the valve seat through the wedge surface. Parallel gate plates are mostly used in low-pressure conditions, relying on the elastic deformation of the valve seats on both sides to compensate for the sealing gap and ensure sealing performance.
One end of the valve stem is connected to the gate plate, and the other end is connected to the handwheel (or actuator). When the handwheel is turned, the valve stem can drive the gate plate to move up and down along the axis of the valve body, thereby regulating the flow rate of the medium.
The working principle of a gate valve is “flow control through the lifting and lowering of the gate plate”: when the gate plate is fully lifted, the valve is fully open, and the medium can flow unobstructed along the pipe; as the gate plate gradually descends, the gap between it and the valve body becomes smaller and smaller, and the flow rate of the medium decreases accordingly; when the gate plate is fully pressed against the valve seat, the medium channel is completely blocked, and the valve is closed.
Different from the “rotational on-off” method of ball valves, the “linear regulation” feature of gate valves gives them an advantage in precise flow control—by slightly adjusting the lifting height of the gate plate, the flow rate of the medium can be finely controlled. Therefore, in industrial scenarios that require stable output flow rates, such as boiler feedwater systems, gate valves are often the preferred choice.
In the process of oil and gas extraction and transportation, ball valves can be regarded as the “core controllers”. It is well known that media such as oil and gas not only have high pressure (usually exceeding 10MPa), but are also volatile. Once leakage occurs, the consequences would be unimaginable. The high-pressure sealing structure of ball valves, such as metal hard-sealed ball bodies, can effectively prevent medium leakage. Meanwhile, oil and gas pipelines often need to switch the transportation direction.
At this time, the “quick open and quick close” feature of ball valves can come in handy, responding quickly to changes in working conditions, reducing the retention time of the medium in the pipeline, and lowering safety risks. Please provide the text you would like translated.
In water supply and drainage systems and sewage treatment equipment, the adaptability of ball valves is also prominent. On the one hand, the medium in water treatment inevitably contains impurities such as sand and suspended solids. If the valve is prone to accumulate impurities, it may clog the pipeline. The full bore design of ball valves can prevent impurity accumulation and significantly reduce the risk of valve blockage. On the other hand, during the sewage treatment process, it is often necessary to switch between aeration and backwashing processes. If the valve opens and closes too slowly, it will affect the treatment efficiency.
The “quick open and quick close” capability of ball valves can precisely address this issue, shorten the process switching time, and enhance the treatment efficiency. Please provide the text you would like translated.
In chemical production, many of the media used are highly corrosive liquids (such as acid and alkali solutions) or toxic gases. Therefore, there are particularly high requirements for the corrosion resistance and sealing performance of valves. Ball valves perform exceptionally well in this regard: they can be made from corrosion-resistant materials, such as valve bodies lined with Hastelloy or fluoroplastics, which can withstand even strong corrosive media. Additionally, their “face-to-face sealing” structure ensures zero leakage, with a leakage rate typically below 1×10⁻⁶ mL/s, effectively preventing the leakage of toxic media and avoiding potential safety incidents.
In power systems such as thermal power and nuclear power, gate valves are often used in critical sections such as boiler feedwater and steam pipelines. Taking the boiler feedwater system as an example, it requires a stable flow output to maintain the water level balance in the boiler. If the flow fluctuates, it may affect the normal operation of the boiler.
The precise flow regulation capability of gate valves allows for maintaining a stable feedwater flow by simply adjusting the height of the gate plate. Moreover, the medium in steam pipelines typically has a temperature exceeding 300°C and a pressure over 16MPa, representing high-temperature and high-pressure conditions. The combination of the wedge-shaped gate plate and metal valve seat in gate valves can maintain excellent sealing stability in such harsh environments, preventing steam leakage.
In municipal pipeline systems for urban water supply and drainage, large-diameter gate valves (typically with diameters exceeding DN300) are indispensable core control components. The main water supply pipelines in cities need to stably convey large volumes of water for a long time, and water demand varies with time.
At this point, the linear flow regulation characteristic of gate valves comes into play—it can precisely adjust the water supply volume according to the water demand at different times, prevent significant fluctuations in pipeline pressure, and ensure stable water supply for residents.
In addition, most municipal pipelines are buried underground and are subject to external loads such as road traffic and soil settlement. Gate valves have high structural strength, can withstand these external forces, and have a long maintenance cycle (requiring infrequent inspections and repairs), making them well-suited for the long-term operation requirements of municipal engineering.
