Some of the most common 2-way valve symbols are ball valves, butterfly valves, plug valves, gate, valves, etc.
The direction of flow is shown by the arrowhead on the line symbols. Two-way valves can be recognized by the two triangles that point towards each other, such as the gate valve symbol seen in figure 2. This makes it incredibly easy to read a diagram once the user knows what each symbol means. The valve symbols used in a P&ID diagram are standardized and the same globally. How do I read valve symbols and P&ID diagrams? How do I read valve symbols and P&ID diagrams?.The symbol typically consists of the actual valve symbol, and the actuation method such as pneumatic, hydraulic, or electric. In each process and instrumentation diagram, valves have specific symbols that make them easy to recognize. In order to trace faults, isolate equipment and locate items for maintenance, the ability to read P&IDs is essential. The diagram indicates the flow directions, safety and control measures, and pressure ratings of a system through visual symbols. The Process and instrumentation diagram, commonly known as a P&ID, shows the connections between process equipment. Figure 1: A process and instrumentation diagram
