【2025 Diagram Analysis】Installation location and orientation of control valves
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The last edit to this post was made by zhoudingshengs on 2025-5-30 at 08:52. The comparison diagram of the installation locations for the control valve is shown below; installation location ① is the optimal position, that is, vertical installation； Installation location ⑤ is the worst option, and it should be avoided as much as possible ； Installation location ② is a secondary option. If there is not enough space, locations ③ and ④ can be chosen.
General regulations and requirements for the installation of control valves: 1. The installation of control valves shall be carried out in accordance with the provisions of the design drawings and design documents. 2. The installation of control valves shall comply with the provisions of relevant standards, such as the Specifications for Construction and Acceptance of Industrial Automation Instruments, and the Specifications for Construction and Acceptance of Electrical Equipment Installation Projects. 3. The equipment required for the installation of control valves, auxiliary equipment, and main materials shall comply with the relevant provisions of ** or industry standards.
The isolation valves upstream and downstream of the control valve, as well as the bypass valve, should be installed simultaneously with the control valve. Typically, there should be a straight pipe section of 10–20D upstream, and a straight pipe section of 4–7D downstream. D is the nominal diameter of the pipe. There are various ways to connect the shut-off valves upstream and downstream of the control valve, as well as the bypass valves; the figure shows six common connection schemes for control valves.
Scheme A features a compact structural layout, occupies less space, is easy to maintain and operate, and allows for easy venting or drainage of the system. However, it often fails to provide sufficient straight pipe sections, which leads to increased noise levels.
Scheme B requires a larger floor space; the position of the control valve can be installed either at the top or at the bottom, which makes it easy to meet operational requirements, but it is difficult to ensure the presence of straight pipe sections.
The structure of Option C is suitable for angle valves; it reduces the number of elbows, requires less space, and allows for a longer upstream straight pipe section in relation to the flow direction measured at the inlet.
Plan D is similar to Plan B and requires a large area.
The structure of Scheme E is suitable for angle valves; compared to Scheme C, the upstream straight pipe section is shorter, which is not conducive to fluid stability.
The installation of the valve positioner should ensure that the signal feedback can accurately and promptly reflect the valve position and any changes in it.