What is the box on this pneumatic ball valve used for?

This box is typically the actuator installed on a pneumatic ball valve, used to control the opening and closing of the ball valve. The actuator drives the rotation of the ball valve using compressed air, thereby enabling control over the fluid flow path. This setup allows the ball valve to be operated remotely or automatically, improving the efficiency and safety of the system. .

It should be used for on-site valve position indication and remote transmission of valve position feedback

What was said upstairs is correct; this refers to the valve positioner and remote feedback.

The one below with the label “KITZ” is a cylinder; cylinders are divided into linear cylinders and rotary cylinders. The cylinder on the cut-off valve is a rotary cylinder. A control signal is sent to the solenoid valve in order to regulate whether air flows into the cylinder or not. When a signal is present, air enters the cylinder, and under the pressure of the compressed air inside the cylinder, it overcomes the force of the spring and rotates, thereby opening or closing the valve (if it is a gas-operated valve). Once the signal is lost, the cylinder returns to its original position due to the action of the spring. The box above is connected to a shaft; when it moves, rotation causes it to open or close, thereby enabling the feedback signal to be activated. This indicates that the valve is open or closed in place. In control systems, this signal is used to detect whether the valve has moved to its proper position, thereby determining whether to proceed with the next action. If a hydrogenation reaction is carried out by introducing hydrogen from the bottom, there are two shut-off valves in the gas inlet channel for safety reasons. One valve remains open throughout the reaction, while the other valve controls whether air is allowed to enter the reactor. If the pressure of the air intake source is low, or if the heating rate of the reactor temperature is abnormal, or if the reactor temperature is too high, it will trigger a safety interlock response. At this point, you first need to close the cut-off valve that is closest to the reactor, check that it is indeed closed, and then close the other cut-off valve. Also, when opening it, do it in reverse order: first open the cut-off valve that is farther from the kettle, then check whether this valve has opened fully, and then open the other valve.