Safety relief valve
The safety relief valve (SBV) is a safety relief device with special tasks within gas pressure regulating systems . In a pressure line, it protects the downstream system against excessively high pressures. The structure of a safety relief valve corresponds to that of a safety valve .
tasks
A safety relief valve is installed after gas pressure regulators to prevent the permissible pressure from being exceeded in downstream systems. This could e.g. B. occur as a result of leakage within the controller or thermal expansion of the gas.
In the case of gas connections in houses, the safety relief valve is also installed downstream of the pressure regulator to ensure that the high pressure in the pipe network cannot get into the customer line even if the pressure regulator is defective. Otherwise, the preset gas / combustion air ratio on the combustion device would change and, in the case of substoichiometric combustion, unburned gases, e.g. B. the poisonous carbon monoxide arise.
In addition, the safety relief valve is used to prevent a safety shut-off valve (SSV) from closing prematurely in the event of a significant change in consumption and delayed controller behavior . The response pressure of the SBV is below the closing pressure of the SAV in order to be able to evacuate small amounts of gas before the SAV closes.
conditions
The response pressure of a safety relief valve is set by the valve pressure spring or its preload and must be approved in Germany by a notified body .
Full stroke SBV for heat exchangers
The full-lift SBV is a special form of the SBV. It opens 100% with a pressure increase of only 15%. These SBVs are mainly used to protect heat exchangers so that both mass flows can be discharged without increasing pressure in the event of a burst pipe.
