Gasified facilities must have protection systems against possible leakage and ignition of gas. There can be many reasons for this, and one of them is a fire in the room. A fire causes an increase in temperature that can reach the flammable limit of the gas and cause it to explode. To prevent this, special valves have been developed to cut off the gas supply in the event of a fire.
Thermal shut-off valve: purpose
The automatic type of valve that shuts off the gas pipeline to all gas-powered appliances during a fire is called a thermal shut-off valve. This device reduces the risk of explosions, injury and physical damage.
The installation of KTZ thermal shut-off valves is regulated by the standards set forth in the fire safety rules. They prescribe:
- To equip any types of natural gas pipelines, regardless of their complexity, branching and the number of consumer devices with temperature-sensitive control and supply cut-off systems.
- Use as protective devices valves designed to operate when the ambient temperature reaches 100degrees Celsius.
- Install thermal blocking modules at the entrance to the room.
Valves are marked in the form of KTZ with a number after it. The number indicates the diameter of the gas supply pipe on which this valve can be installed.
Operation principle
Thermo-shutoff valve consists of a body with a threaded connection, a fusible insert, a spring mechanism and an element (shutter) in the form of a plate or a ball that closes the channel.
In the initial state, at normal room temperature, the shut-off element of the valve is cocked and held by a fusible link. When ignited, the overall temperature rises, reaching its mark of 85-100 degrees leads to the melting of the insert and the release of the cut-off mechanism. The latter, in turn, under the action of a spring, blocks the gas flow channel.
Thermal shut-off valve (KTZ) can work with any gases. After operation, it is replaced with a new one. It is possible to replace the fusible insert with another and further use the product.
Installation rules
In order for the thermal shut-off valve to work reliably, you must follow the rules for its installation:
- Threaded valves must be installed in lines with a pressure not higher than 0.6 MPa. Flanged valves withstand pressure up to 1.6 MPa.
- The flow capacity of the valve must be at least as large as the flow capacity of the gas line.
- Install the thermal shut-off valve onthe gas pipeline is needed in the very first place, and then the rest of the fittings.
- KTZ should be installed indoors and protect fittings that are not designed for high heat.
- The valve axis can be positioned in any direction.
- Take into account the flow of gas, the direction of which is indicated on the body of the device.
- Installation of the valve in places close to heating elements, the air temperature near which can exceed 53 degrees, is excluded.
- The built-in thermal shut-off valve must be checked for leaks.
- After installing the KTZ, it should not be subjected to additional pipe pressure by bending or unscrewing the device.
- Access to the valve must be free and unobstructed.
Conclusion
When buying a thermal shut-off valve, you should make sure that the channel cut-off mechanism has not worked, which sometimes happens during transportation. With complex gas distribution inside the premises and the presence of several fuel consumers located in different parts of the building, it is recommended to install several shut-off valves for each branch.
