The spring is also used in the water level pressure switch, the principle is as follows: the spring depends on the two heads of the inner diameter card mounted on the reed above the external force (ie, water pressure conversion value) acting on the reed, when the appropriate size (ie, a certain water pressure) , The deformation of the spring can make the reed elastic deformation, so that the plug is connected, and then through the circuit conversion, the switch can achieve the purpose of controlling the water level value. In addition to the general requirements, the following technical requirements are required:
(1) both ends of the grinding, grinding the amount of not less than a wire diameter, and the end without step;
(2) Size d ± 0.07 Check the four different diameter positions with 0.2 × d ± 0.07 pass gauge;
(3) spring two ends and circle, in the work circle pressure and circle before the head can not be indented into the work circle.
In this structure, the work circle for the cylindrical coil spring, the head and circle, made of conical. Its main advantages are: spring processing technology is simple, low cost.
The main drawback is that in the process of spring grinding, due to the influence of the helix angle φ, the inner diameter d ± 0.07 is easy to accent. If the spring manufacturer with manual grinding, diameter and vertical degree is more difficult to guarantee. In this way, between the spring and the reed will produce a relative radial string, due to the instability of the force transmission, the stability of the switch water level is difficult to guarantee.