A first diaphragm and a second diaphragm are disposed between a valve element and a body, a diaphragm chamber is formed between the first diaphragm and the second diaphragm, the first diaphragm separates a valve chamber from the diaphragm chamber, and the second diaphragm separates the diaphragm chamber from a back pressure chamber. The diaphragm chamber communicates with an output port, the valve chamber and the back pressure chamber communicate with an input port. A difference between an effective pressure receiving area of the first diaphragm and an effective pressure receiving area of the second diaphragm is equivalent to a passage area in a valve seat.

A first diaphragm and a second diaphragm are disposed between a valve element and a body, a diaphragm chamber is formed between the first diaphragm and the second diaphragm, the first diaphragm separates a valve chamber from the diaphragm chamber, and the second diaphragm separates the diaphragm chamber from a back pressure chamber. The diaphragm chamber communicates with an output port, the valve chamber and the back pressure chamber communicate with an input port. A difference between an effective pressure receiving area of the first diaphragm and an effective pressure receiving area of the second diaphragm is equivalent to a passage area in a valve seat.

An actuator of a regulator is connected to one end of a valve rod. The actuator includes a shell, a limiting component, a diaphragm assembly, and an elastic element. The diaphragm assembly is movably sleeved on the valve rod. Further, the elastic element is coupled to the diaphragm assembly and is movably sleeved between the diaphragm assembly and a tip of one end of the valve rod, in a compressed state. An inner diameter of a portion of the limiting component is smaller than an outer diameter of an upper portion of the diaphragm assembly. The limiting component is located above the diaphragm assembly.

An actuator of a regulator is provided. The actuator is connected to one end of a valve rod (212/312). The actuator comprises a shell (203/303); a limiting component (205/305), the limiting component (205/305) being disposed on an inner wall of the shell (203/303); a diaphragm assembly (204/304), the diaphragm assembly (204/304) being accommodated in the shell (203/303), and the diaphragm assembly (204/304) being movably sleeved on the valve rod (212/312); and an elastic element (226/326), the elastic element (226/326) being accommodated in the shell (203/303), and the elastic element (226/326) being coupled to the diaphragm assembly (204/304), and being movably sleeved, between the diaphragm assembly (204/304) and a tip of one end of the valve rod (212/312), on the valve rod (212/312) in a compressed mode. An inner diameter of a portion, making contact with the shell (203/303), of the limiting component (205/305) is smaller than an outer diameter of an upper portion of the diaphragm assembly (204/304), and the limiting component (205/305) is located above the diaphragm assembly (204/304). A fluid regulator having the actuator is provided. By means of the actuator, the technical problem that a valve rod, a valve flap and a valve port are deformed and even damaged due to extremely large stress in the regulator is solved, the valve rod, the valve flap and the valve port of a valve element assembly are buffered to a certain extent when bearing extremely large stress, and therefore damage is avoided.