Among the several kinds of valve types, the check valve would be a popular option. It would be used for closing the pipes along with preventing the backflow. The backflow would occur when any substance in the pipe would flow in the opposite direction, especially when the valve is closed. You would come across wide varieties of valves. Some of them would be inclusive of check valves, cone check valves, stop-check valves, Sanitary Valves and disk check valve and more.
In a standard valve, the command given to open at a specific point would not require any feedback for verifying whether the valve has opened to that position or not. However, with the use of valve positioner, the positioner would read the command given to open the valve. It would then verify the position and readjust it. The command would be carried out until it would come to the precise position as required by the command. It would enable great precision in the adjustment.
Several categories of valves
Apart from the valve positioners, you would come across wide varieties of valves. There would be several categories of valves available in the market.
The foremost category would be a common one. A ball in the shell of the value would fit tightly against the side of valve from where the water would come in. The ball would be pushed against the spring when the water moves through the pipe and pushes the ball. It would enable the water to go through the valve. In event of you turning off the water, the ball would be pushed in the place through the spring. It would help you keep the water from flowing through the pipe in the backward direction.
The second kind would be the product encompassing override control. It would stop the flow despite the flow of pressure or direction. However, it would also deliberately shut by an external mechanism. It would prevent any flow despite the pressure pushing it forward.
The third kind would be similar to check valves. However, the plug sealing the valve would be shaped similar to a cone. It would also be called lift check value whereby the disc, also called a lift would be lifted off the seat through high pressure of upstream fluid enabling the flow to the downstream side.
The fourth kind would be the disk valve that would be called as swing check valve. It would operate in similar manner as the cone and ball valves. The plug settling over the opening would be the disk.