Shell Boilers -
Part 5：Safety Appurtenances and Instruments
鍋殼鍋爐
第5部分：安全附件和儀表
1 Scope
This Part of GB/T L 6507 specifies the requirements of setting and selecting etc. for safety appurtenances and instruments of shell boilers, including safety valve, pressure measuring device, water level measuring device, temperature measuring device, blowdown and drainage device and safety protection system.
This Part is applicable to the shell boilers defined within the scope of GB/T 16508.1.
2 Normative References
The following documents are essential for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 1576 Water Quality for Industrial Boilers
GB/T 12145 Quality Criterion of Water and Steam for Generating Unit and Steam Power Equipment
GB/T 12241 Safety Valves - General Requirements
GB 13271 Emission Standard of Air Pollutants for Coal-burning Boilers
GB 50041 Code for Design of Boiler Plant
TSG G0001 Boiler Safety Technical Supervision Administration Regulation
TSG G0002 Supervision Administration Regulation on Energy Conservation Technology for Boiler
TSG ZF 001 Safety Valve - Safety Technical Supervision Administration Regulation
3 Terminologies and Definitions
For the purposes of this document, the following terminologies and definitions apply.
3.1
Safety appurtenances
Auxiliary appurtenances and instruments for the safety operation of boilers include safety valves, pressure measuring devices, water level measuring devices, temperature measuring devices, water level alarms, blowdown devices, interlock protection devices and main valves etc.
3.2
Instruments
The device used for measurement solely or together with other equipment.
3.3
Safety ignition duration
The safety time for which the ignition flame of the burner is ignited, namely the maximum permissible duration of the ignition fuel control valve in open state where no ignition flame appears.
3.4
Safety flameout duration
The time interval from the flame extinction to the time when the main fuel control valve starts to close where the burner flames out during the operation.
4 Basic Requirements
4.1 Safety appurtenances and metering instruments for boilers shall meet the requirements of relevant laws and regulations and respective product standards and meet those specified in TSG G0001 Boiler Safety Technical Supervision Administration Regulation and TSG G0002 Supervision Administration Regulation on Energy Conservation Technology for Boiler, ensuring the high-efficient, safe and reliable operation of boilers.
4.2 All necessary parts as required in drawings and technical documents of boilers shall be equipped with measuring devices for pressure, water level and temperature. All those devices shall be safe, reliable and accurate and be provided with proper measuring range and local and remote transmission measuring devices for pressure, water level and temperature as required in regulations.
5 Safety Valves
5.1 Basic requirements
5.1.1 Technical requirements for the manufacturing license of safety valves, product type test, nameplate and quality certificate shall be in accordance with those specified in TSG ZF 001 Safety Technical Supervision Regulation for Safety Valve .
5.1.2 Each boiler shall be installed with at least two safety valves (including boiler drum and superheater safety valve). In case of any of the following conditions, only one safety valve may be installed:
a) The steam boiler whose rated evaporation is less than or equal to 0.5 t/h;
b) The steam boiler with a reliable overpressure interlock protection device and rated evaporation less than 4t/h ;
c) Hot water boiler with a rated thermal power less than or equal to 2.8 MW.
5.2 Selection of safety valve
5.2.1 For safety valve of steam boilers, fall-lift spring safety valve, lever safety valve or controlled safety valves (pulsed safety valve, pneumatic safety valve, hydraulic safety valve and electromagnetic safety valve etc.) shall be adopted and all these valves selected shall meet those specified in TSG ZF 001 Safety Technical Supervision Regulation for Safety Valve and the requirements of corresponding technical standards.
5.2.2 For steam boilers whose rated operating pressure is less than or equal to 0.1 MPa, dead weight safety valve or water-sealed safety equipment may be adopted. In case that hot water boiler is equipped with water-sealed safety equipment, safety valve may not be installed. The inner diameter of sealing water tube for water-sealed safety equipment shall be determined in accordance with the rated evaporation (rated thermal power) and rated operating pressure of boilers and no less than 25mm. The sealing water tubes of water-sealed safety equipment shall not be provided with valves, but anti-freezing measures.
5.3 Total discharge of safety valves
5.3.1 The total discharge of safety valves on the steam boiler shell and superheater shall be greater than rated evaporating capacity of boiler; after all those valves are opened, steam pressure in the shell shall not exceed 1.1 times of design pressure. The discharge amount of safety valve at superheater outlet shall guarantee that the superheater has sufficient cooling. The flow channel diameter of safety valve for steam boiler shall not be less than 20mm. The discharge amount shall be determined in accordance with one of the following methods:
Foreword I
1 Scope
2 Normative References
3 Terminologies and Definitions
4 Basic Requirements
5 Safety Valves
6 Pressure Measuring Device
7 Water Level Measuring Device
8 Temperature Measuring Device
9 Blowdown and Drainage Device
10 Safety Protection Devices
11 Monitoring & Metering Instrument
12 Other Requirements
