A valve is used to shut off or control liquids and gases. With the help of valves, the flow rate in a pipeline can be accurately measured and safely separated from the environment. In addition, there are safety valves that, on the other hand, allow large mass flows to pass through in order to quickly compensate for unacceptable pressure conditions, for example in a container. The closing portion of the valves moves approximately parallel to the direction of flow. The flow is interrupted by pressing the sealing surface of the closing part against the bore of the respective valve shape or seal seat. The sealing parts can be, for example, plates, cones, balls or needles.
The different valve types differ in terms of construction and pressure loss, actuation type, task or even the design of the closing body.