Some questions from a chemistry beginner regarding xv and xzv
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This post was last edited by Lord Ningguang at 17:11 on January 30, 2025. Both XV and XZV represent shut-off valves. What are the specific differences between them and their respective special functions? What does the code name PB mean, and what is its purpose?
XV usually refers to a regular shut-off valve, which is used to control the opening and closing of fluid flow. Meanwhile, xzv refers to shut-off valves with special purposes; for example, they may have additional safety or regulating functions. The PB code is generally used to denote pressure gauges, which are primarily used to measure and display the pressure within pipes or containers. .
They have different functions. 1. xzv refers to a shut-off valve. In production, it is used for installation on pipelines; it facilitates operation, reduces manual labor intensity, and features high sensitivity. 2. The xv series of self-acting control valves, which are forged steel valves, are mainly suitable for use in the pipelines of various systems in thermal power plants. They can be used to control the flow of various types of fluids, including air, water, steam, various corrosive substances, slurry, oils, liquid metals, and radioactive materials. In layout diagrams, PB usually stands for “wiring arrangement,” referring to the layout and path of the circuit wires. In the renovation drawings, PB clearly indicates the locations of power outlets, switches, etc., as well as the routing of electrical wires. This is crucial for ensuring the safety and functionality of the electrical circuits.
XV generally refers to ordinary control valves, XZV refers to SIS system valves, and PB should be pressure (I’m not quite sure what B means)
According to HG/T 20505-2014: 1. X is not defined; however, industry practice dictates that XV refers to the shut-off valve in the BPCS； 2. Z is a modifier character indicating a SIS system variable; in other words, XZV represents a shut-off valve in the SIS system ； 3. P represents pressure; B is undefined – it is necessary to check the first page of the design documents; it is presumed to be an on-site pressure indication. By the way, don’t speak rashly when you’re not sure; it can easily mislead others.
XV generally refers to the shutdown valve in the process control system, while XZV refers to the shutdown valve in the SIS system. Based on what’s shown in your diagram, PB likely refers to a Panic Button, that is, an emergency stop button for manually controlling this valve on site
This post was last edited by A Bai_ugUmK on 2025-3-13 10:00. VX and VZX may mean the same thing; it depends on the project and the regulations set by the design institute. XV can denote a valve leading to the DCS or SIS, and similarly XZV can also denote a valve leading to the DCS or SIS. It can also be as mentioned above: XV goes to DCS, and XZV goes to SIS. It depends on the specific project regulations. PB; in the legend, P generally denotes pressure, while B is undefined. It is recommended to check the legend of this drawing. In PID control, PB represents the proportional band. But this is a on/off valve, so it shouldn’t be. . . Look at this one below; it’s likely the reset button. The meaning of the letters in PID diagrams: https://bbs.hcbbs.com/thread-3036429-1-1.html (Source: Haichuan Chemical Industry Forum)
There is an irregularity in this diagram: two XZV-62203 units in the diagram violate the principle of unique tag numbers, meaning that a single tag number cannot be assigned to multiple units. In the diagram, XZV-62203 denotes both the cut-off valve and the interlock logic; violating the principle of uniqueness will lead to confusion.