Valves are an indispensable component of industrial equipment, which control the flow rate, pressure, and direction of fluid media, and have functions such as shut-off, regulation, and control.
Valves play an important role in industrial production processes. Therefore, selecting and installing valves correctly is of great significance for the normal operation of production.
1、 Principles for selecting valves:
1. Select based on conditions such as temperature, pressure, type of medium, and corrosiveness;
2. Select according to the nature of the job: for those with high vacuum requirements, high vacuum or large-diameter butterfly valves should be used;
3. According to the pipeline transportation capacity, it is generally recommended to use gate valves for low-pressure pipelines; High pressure pipes should use shut-off valves or ball check valves;
4. Select based on economic accounting (including price);
5. Select according to the pipeline layout: whether it is a horizontal or vertical pipeline, and whether it is exposed or concealed.
2、 Selection of commonly used regulating valves:
1. Ordinary straight through single seat adjustment:
The flow characteristic is linear, with an adjustable ratio of 100:1~200:1, suitable for use in low flow situations. This type of valve has a simple and compact structure, but its flow area is limited to a certain extent and it is not suitable to use small flow throttling elements.
2. The sleeve type straight through single seat adjustable valve can be installed at any position, and its flow characteristics can be changed according to the needs by changing the shape of the throttle to meet the requirements of different working conditions. This type of regulating valve has a large flow area and a relatively large adjustable ratio, so it can be used in high-pressure gas applications.
3. The structural characteristics of this type of regulating door with angle type three-way double hole plate are as follows: the three channels are connected by two 90 ° elbows, and there is a circular throttling element and a circular chamber composed of a central cone between the two 90 ° elbows in the middle channel. When opened, the volume of the middle annular chamber changes; After closing, the cross-sectional area of the two 90 ° elbows also changes accordingly to achieve control over the airflow. Due to the fact that each channel has a certain flow cross-section, its total flow cross-section can reach 10m3/ H or above; Moreover, there is no relative motion between the channels, which can eliminate energy loss caused by leakage; In addition, due to the different cross-sectional areas of each channel, the pressure difference between them is compensated, thereby achieving the goal of energy conservation for the entire system.
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