The rod passes through the disc into an actuator which regulates the movement of the disc, rotating the disc either parallel or perpendicular to the flow of media.

The butterfly valve has a rod and a disc. If you want to learn about more than 18 types of valves in detail, you can buy my course, how to be an expert in piping valves.A butterfly valve is a machine that rotates its disk by a quarter-turn to allow or restrict the flow of media within the diameters of large pipes. Now I will explain to you the specific valve symbol that is used in P&ID and isometric drawings. This arrangement is cost-effective in large-size relief operations. This type uses a small relief valve to operate the main relief valve. Pilot-operated relief valves are just working as relief valves but are used for large-size piping. The vacuum valve prevents damage to the equipment from negative pressure. In the event of over-pressure, this valve release the pressure, and in case a vacuum is created in the tank, this valve allows air to enter the tank. This valve serves the function of the relief valve and vacuum valve. Now the breather valve is used on the cone roof tank. The next symbol is the relief valve used to protect the piping system or equipment from overpressure. In most cases, a globe valve is used as an angle valve. Here in the image above, the first symbol is of angle valve. Watch this video which will explain to you all aspects covered in this article. This type of valve is used in the pump discharge line to ensure the pump will not suffer from low inlet pressure, which leads to cavitation. The last symbol is of automatic recirculation valve. You must be very careful while reading this type of symbol as it can easily be overlooked. You can see that it is the same as a check valve the only difference is the written text below the valve symbol. The next symbol is the excess flow valve. These check valves can be swing check or lift check valves. The subsequent two symbols are a check valve and a stop check valve. Similarly, the next two symbols are for three-way and four-way valves. There are dedicated symbols for a gate, globe, plug, and ball valves which I will explain to you in minutes. Now when you look at the symbol on the drawing, it just gives you an indication that some kind of valve is used, but it will not provide you with information about the type of valve, whether it is a gate, globe, or plug type valve. These symbols are generic in nature - for example, the first symbol of a valve. Here in the image above, you can see commonly used symbols for valves. Gaskets & Spectacle Blinds Expand / Collapse.Pipe Fittings Inspection – Visual & Testings.

Check valve isometric symbol