1. Check Valve: It reduces the excessive pressure in the container by automatically opening the valve to discharge gas.
(1) Advantages: Only the part of the pressure in the
Pressure Vessel that is higher than the specified pressure is discharged, and when the pressure in the vessel drops to the normal operating pressure, it will automatically close, so it can avoid having to discharge all the gas once the vessel is overpressured. waste and production disruption. The device itself can be reused many times and is relatively easy to install and adjust.
(2) Disadvantages: The sealing performance is poor. Even a Check Valve that meets the regulations will inevitably have slight leakage under normal working pressure; due to the inertia of springs, etc., there is a lag in the opening of the valve, so the pressure relief response is slow. slow. In addition, if the Check Valve is used as a medium for some unclean gases, the valve may be clogged and the valve disc may be stuck.
(3) Scope of application: It is suitable for equipment with relatively clean gas media, such as air, water vapor, etc. It is not suitable for equipment with toxic media; it cannot be used for equipment where violent chemical reactions may occur in the equipment, causing the pressure to rise sharply. device of.
(4) When selecting a Check Valve, its discharge volume must be greater than the safe discharge volume of the equipment. The structural form of the Check Valve should be selected according to the process conditions of the equipment and the characteristics of the working medium, and the appropriate Check Valve should be selected according to the maximum allowable working pressure.
Note: The safe discharge amount of a pressure vessel refers to the amount of gas that must be released per unit time to ensure that the pressure of the pressure vessel does not increase when it is overpressured. The displacement of the Check Valve refers to the discharge volume per unit time under the discharge pressure when the Check Valve is in the fully open state.
2. Bursting disc: It uses the bursting element to break under high pressure to discharge gas.
(1) Advantages: good sealing performance, no leakage when the container is working normally; the rupture disc has a high rupture speed, so the pressure relief response is fast; if the medium contains oil and other debris, it will not affect the operating pressure of the device components Influence.
(2) Disadvantages: After the pressure relief action is completed, the blasting components cannot continue to be used. Once the container is overpressured, it is forced to stop operating; the blasting components are in a high stress state for a long time and are prone to premature failure due to fatigue, so the component life is relatively long. short and needs to be replaced regularly. In addition, the operating pressure of blasting components is difficult to accurately predict and strictly control.
(3) Scope of application: It is suitable for use in containers where chemical reactions may occur with a sharp increase in pressure, or where the medium is highly toxic. It is not easy to be used in liquefied gas storage tanks. It is also not easy to use for containers with large pressure fluctuations, that is, containers with more opportunities for overpressure.
