What is the difference between American standard check valves and safety valves

What is the difference between American standard check valves and safety valves
There are significant differences between American standard check valves and safety valves in multiple aspects, mainly reflected in the following aspects:
Function: The main function of the American standard check valve is to prevent medium backflow, prevent pump and drive motor from reversing, and discharge the container medium. American standard check valves are commonly used as bottom valves in pumping equipment or in pipeline systems that require prevention of medium backflow. The main function of safety valves from American standard gate valve manufacturers is to prevent excessive pressure. When the pressure inside the equipment, container or pipeline increases beyond the allowable value, the valve automatically opens and fully discharges to prevent the equipment, container or pipeline and pressure from continuing to rise, providing safety protection.
Structure: The structure of a check valve is relatively simple, usually with only one valve. For example, a lift check valve has a structure similar to a globe valve, but lacks a stem that drives the valve disc. The structure of a safety valve is more complex, and it usually requires collaboration between a main valve and an auxiliary valve.
Working principle: Check valves rely on the flow of medium to open and close. When the medium flows, the valve disc opens; When the medium stops flowing or backflows, the valve disc closes. The safety valve is controlled to open and close by adjusting the pressure. When the pressure of the medium in the equipment or pipeline increases beyond the specified value, the safety valve automatically opens to discharge the medium.
The marking on the valve: Generally, only one arrow is installed on the check valve to indicate the direction of medium flow. And safety valves need to be labeled with relevant parameters, such as pressure, flow rate, temperature, etc., so that users can better understand and control the operation status of the valve.
In summary, there are significant differences between check valves and safety valves in terms of function, structure, working principle, and valve markings. When selecting and using, a comprehensive evaluation should be conducted based on specific process requirements, medium characteristics, and working environment factors to ensure that the valve can function and ensure the safe operation of the system.