Check Valve, Diaphragm Valve - Directional Flow Valve

The third type of valve is used to control the flow of fluid. Lined Check Valve can ensure that the fluid can only flow in one direction, that is, the pressure increases. In the most common design, the pressure of the upstream fluid forces a spring-loaded lifting plate to open, allowing the fluid to pass. If the downstream pressure or reverse pressure increases, the lifting plate is pushed back into the valve seat and prevents the fluid from passing in the opposite direction. Check valves can also be configured with fixed or fixed or adjustable cracking pressure.
Some ball valves and rubber-lined fluorine-lined diaphragm valves are designed with multiple channels. In most channel valves, the fluid can only enter the valve from one inlet, but can flow out from one of multiple outlets depending on the position of the actuator. Multi-channel valves can freely choose whether to set the shut-off position.
Overpressure protection valve
This type of valve prevents the system pressure from exceeding a certain preset value. This valve can be divided into two major categories: relief valves and bursting butterflies.
One type of relief valve is called a proportional relief valve. It has a vent on the valve body that leads to the outside. When the pressure in the system exceeds a certain value preset by the operator, the vent is opened. The quantitative release of fluid relies on the spring-loaded tail seat. When the system pressure returns to the preset level, the vent closes.
Safety relief valves open quickly and release the system medium. Due to their critical safety protection function, regulations require the installation of such valves in some applications. Safety relief valves, proportional relief valves and check valves are not interchangeable because they have different functions.
Exploding butterflies are mainly used to protect sampling cylinders from overpressure. Overpressure may occur if the temperature rises during the conveying process. Similar to the relief valve, the bursting butterfly is connected to the outside world. When the pressure reaches a certain value preset by the operator, the metal diaphragm will rupture. Once this action is activated, the bursting butterfly must be replaced. Some regulations related to material transmission stipulate that compressed gas cylinders must be equipped with pressure relief valves. Exploding butterflies are a more economical choice in such applications.