Calibration standard provisions
1、National Quality Supervision Bureau of Boiler Pressure Vessel Supervision Bureau promulgated the "steam boiler safety technology and monitoring procedures"
Section 146, " the boiler safety valve should be at least check once a year. The check should normally be carried out under the boiler running."
2、Issued by the Ministry of Electric Power Industry, "Electric Power Industry Boiler and Pressure Vessel monitoring procedures" (DL612-1996)
9．1．13 Boiler installation and completed repair and the safety valve after the repair, the valve should check the pressure of the starting seat pressure. Charged magnetic assisted operating mechanism of electromagnetic safety valve, in addition to mechanical check, we must also do remote operation of electrical circuit testing and automatic loop pressure relay operation test.
Purely mechanical spring-type check valve can be used to adjust hydraulic device, generally under 75% ~ 80% rated pressure. The safety valve after hydraulic device adjustment, should be at least review to the actual starting seat of the minimum starting seat value of the safety valve.
9．1．14 safety valve should be conducted steam release testing on a regular basis. Boiler safety valve test interval is not more than a small repair interval. electrical circuit test of electromagnetic safety valve should be carried out once a month. All kinds of pressure vessel safety valve discharge steam test should be carried out at least once a year.
9．1．15 It is not allowed to separate safety valve when the boiler is running.
9．1．16 The safety valve boiler without check should have strict prevent overpressure steps when it is in the ignition to start and in the process of checking, and be taken under the supervision of the implementation. When checking, verification officer shall not leave the scene half-way.
3、Promulgated by the State Power Corporation, "to prevent electricity production major accidents 25focus requirements " provisions：
3．2．1 Prevent boiler water scarcity and over-temperature super-pressure operation, strictly prohibited in the insufficient number of water gage (referring to the number of the water level correct instructions of the water gage), run under safety valve solution situation
3．2．4 Boiler overpressure hydraulic pressure testing and setting should be carried out strictly in accordance with procedures
3．2．4．1 Large-capacity boiler over-pressure testing and thermal hydraulic safety valve check should be done to develop specific technical measures, to prevent the step-up too fast or pressure, steam temperature without control cause over-pressure and temperature phenomena.
3．2．4．2 Boiler water pressure in the ultra-pressure water pressure testing and hot safety valve setting, and not test personnel is forbidden to enter the test site
Chapter 4 Prevention of pressure vessel explosion accidents
In order to prevent the occurrence of pressure vessel explosion accidents, we should strictly enforce the "Pressure Vessel Safety Technology supervision order", "Electric Power Industry Boiler and Pressure Vessel monitoring order" (DL 612-1996), "Pressure Vessels using Registration and Management Rules" and other relevant provisions and focused on the followings:
4．1 To prevent over-pressure
4．1．1 1 According to device characteristics and the systems actual situation, develop operational procedures for each pressure vessel. Operating procedures should be clearly the emergency treatment under abnormal condition, to ensure that any pressure vessel operating conditions do not over-pressure, super-temperature operation
4．1．2 All kinds of pressure vessel safety valve should be checked regularly and taken emission test
4．1．3 In the operation of pressure vessels and their safety accessories (such as safety valves, sewage valve, meter monitoring, interlocking, automatic devices, etc.) should be in normal working condition. Pressure vessels with automatic adjustment and protection devices, the withdrawal of its protective devices shall be approved by the chief engineer, after the withdrawal of protection devices, should implement remote control operations and strengthen surveillance, and should be a deadline to resume.
4．1．4 Deaerator running and operating procedures should be consistent with " power plant pressure-type deaerator safety technology provides" (energy security 11991) 709) requirements. Deaerator switch point between the two ends should according to " power plant pressure-type deaerator safety technical requirements" after accounting procedures and define clearly in the running procedures and strictly enforced in operation, it is prohibited high-pressure steam source directly into oximetry.
4．1．10 Cell system, water supply system, deaerator should be equipped with at least two fall lift type safety door, and improve the deaerator automatic voltage regulator and alarm device
4．1．11 Deaerator and other pressure vessels safety valve total emissions capacity should be able to meet their maximum steam entering operating conditions without over-pressure .
4．3 In-service pressure vessels should be combined with equipment, systems maintenance, according to "Pressure Vessel Safety Technology supervision order" and "the power industry boiler pressure vessel monitoring procedures" (DL 612-1996) regulations, to carry out regular inspection system.
4、the PRC National Development and Reform Commission issued the power industry standard "boiler safety valve application guidelines" (DL/T959-2005)
8 On-site verification and adjustment of safety valves
8.1 On-site verification
8.1.1 Boiler installation and completerepair and after the safety valve repair, should check the setting pressure of safety valve.
8.1.2 With magnetic or other supporting operating mechanism safety valve, in addition to mechanical check, we must also do remote operation of electrical circuit testing and automatic loop pressure relay operation test.
8.2 The on-site power plant safety valve calibration methods commonly use hot-line calibration, and can be divided into using specialized equipment (safety valve online constant pressure instrument) to check and step-up jumping verification. Step-jumping check due to poor working conditions, more take-off times, will bring the sealing surface damage, noise pollution, and check safety and other problems.
8.2.1 Purely mechanical spring-loaded safety valve and butterfly spring safety valve can use safety valve online constant pressure instrument to check and adjust. Check adjustments can be taken under the unit to start or run the course load (typically 60% ~ 80% of the rated pressure).
8.2.2 The first after online constant pressure instrument safety valve should deal with the lowest take-off value of the actual take-off safety valve for review, after review, the error value is within the set pressure bias setted in Table 5, the others using safety valves online constant pressure instrument may not have to do real-jump test
8.2.3 on-line constant pressure instrument used and actual jumping value error shall be guaranteed within the allowable scope, and has automatic data recording and processing functions, to prevent human error. on-line constant pressure instrument and being measured safety valve should have a certain safe distance.
8.2.4 the pressure sensors and force sensors of on-line constant pressure instrument should be regularly checked.
8.3 In-service boiler safety valve should be at least checked once a year. Each inspection should be carried out minor repairs cycle, if necessary, verify or emission test should be carried out. All kinds of pressure vessel safety valve should have emission test or online check at least once a year.
8.4 After passing a check valve should be locked or added lead sealing, and recorded in boiler technical log book or pressure vessel technology file.
5、 State administration of Quality Supervision, Inspection and Quarantine promulgated the "safety valve maintenance personnel Examination Program" (TSG ZF002-2005)
The safety valve on-line constant pressure instrument equipment composition and features, working principle, calibration procedures and calibration methods, equipment repair and maintenance and Notes
