New type safety valve

Abstract

The new type safety valve as an indirectly acting valve is a superpressure protecting device. It includes three separated parts of one main valve installed in forward direction, one supplementary valve installed in reverse direction and one release controlling valve connected into one integral through pulse pipes with serially connected trap filter. The main valve and the supplementary valve are leakless safety valves and the release controlling valve may be manual, solenoid or pneumatic one. The new type safety valve has simple structure, low manufacture cost, stable performance and long service life.

Description

1. Technical field [0001] The invention relates to a safety valve, especially an indirect-acting safety valve in which the main valve and the auxiliary valve are separately set. [0002] The safety valve is an essential overpressure protection device for all pressure vessels or systems with variable pressure media inside. [0003] The object of the present invention is to provide a new type of indirect acting safety valve especially used in the nuclear reactor overpressure protection system using light water as the reactor coolant. Its working principle is shown in FIG. 1 . When the valve inlet nozzle contains pressure medium water or steam, the medium causes the main valve disc [2] to generate an upward force, which forms together with the force of the main valve pre-tension spring [7] on the main valve disc [2] The sealing force between the main disc [2] and the main valve seat [49] increases with the increase of system pressure (see Figure 3). At the same time, the water ...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of the integral or split vertical formal installation is that the main spring that plays a controlling role is subjected to the high temperature of the pressure medium for a long time. Due to the high temperature relaxation and deformation of the spring, the opening pressure setting of the valve is easy to drift.

[0006] The disadvantage of the overall flip-chip plus condensate seal is that when the safety valve is activated to discharge high-temperature pressure medium, the body of the main valve will be subject to strong thermal shock, especially for thick-walled valve bodies.

Because the thermal shock stress is proportional to the cube of the valve body wall thickness, as the valve body wall thickness increases, the thermal shock stress value increases rapidly, and the unacceptable thermal shock stress limits the increase of the valve body wall thickness, thereby limiting the valve's performance. The increase of the displacement and the increase of the temperature of the medium used

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