Introduction to the experience of pre-service inspection of condenser copper pipes

Abstract: The experience introduction information of pre-service testing of condenser copper pipes is provided by excellent flowmeter and flowmeter manufacturers and quotation manufacturers. The deterioration of the condensed water quality during the operation of the unit is mostly caused by the rupture or perforation of the steel pipe, which causes the circulating water to leak into the steam side. In severe cases, it will cause a large area of ​​scaling in the heated noodle house of the boiler, causing bulge leakage. The cold wall of Yunfu Power Plant Unit 1 occurred in 1994. Area drum kit. For more flowmeter manufacturers to select models and price quotations, you are welcome to inquire. The following is an introduction to the experience of pre-service testing of condenser copper pipes. The deterioration of the condensed water quality during the operation of the unit is mostly caused by the rupture or perforation of the steel pipe, which causes the circulating water to leak into the steam side. In severe cases, it will cause a large area of ​​scaling in the heated noodle house of the boiler, causing bulge leakage. The cold wall of Yunfu Power Plant Unit 1 occurred in 1994. The source of the area bulge leak is the condenser copper tube leak. There are two main reasons for the leakage of the condenser copper tube: First, there is a quality problem in the new copper tube itself. Second, the circulating water quality is poor. Controlling the quality of the newly installed copper pipes is an important means to prevent early leakage of the condenser. In the article 'Preventing the Exposure Accidents of Large-capacity Boiler Pressure-bearing Components' in 'Twenty Key Requirements for Preventing Major Accidents in Electric Power Production', it is also clearly required that a comprehensive inspection and inspection should be carried out before installing the condenser copper pipes. 1 Copper tube production process 1.1 Production process of copper tube Production process of copper tube: copper billet—extrusion—rough pull—Straightening—fine pull—cut—Eddy Current Testing—heat treatment—Ammonia fumigation, mechanical property test—Finished packing. 1.2 Eddy current testing process Eddy current testing processes are as follows: a) testing equipment A-scanning eddy current flaw detector, mechanical transmission device, through-type coil. b) Detection frequencyφ25mm×The detection frequency of 24kHz is selected for the 1mm HSn70-1 brass tube;φ25mm×The detection frequency of 35kHz is selected for the BFe10-1-1 white copper tube of 1mm. c) The standard sample aperture isφA group of standard holes of 0.8mm, each group is sampled evenly on three circles. d) The transmission speed is 1.5m/s. e) The terminal delay time is 0.2s. f) Process standard implementation GB5248—85 'Eddy Current Testing Methods for Copper and Copper Alloy Seamless Tubes'. 1.3 Ammonia fumigation, mechanical performance test and eddy current test results The ammonia fumigation test of HSn70-1 brass tube is generally qualified. The copper pipe flaring, flattening and tensile test data conform to GB8890—88 Technical requirements in 'Copper Alloy Tubes for Heat Exchangers'. The pass rate of eddy current inspection of HSn70-1 brass tube is between 60% and 70%, and the pass rate of eddy current inspection of BFe10-1-1 white copper tube is between 40% and 50%. 2 Factors Affecting Product Quality 2.1 Timing of Eddy Current Testing In the production process, the eddy current testing process is arranged before heat treatment. There is a reason for the manufacturer to arrange this way. The yield of copper tubes is not high. If it is arranged after heat treatment, it is bound to Increase heat treatment equipment, man-hours and costs, but this arrangement is unfavorable to the quality control of copper tubes, and copper tubes with defects such as cracks and overheating generated from eddy current testing to the completion of heat treatment cannot be selected. When the copper tube of the condenser of Yunfu Power Plant Unit 1 was replaced, 6 cracked copper tubes were found by eddy current testing before installation. After analysis by the manufacturer's technicians, it was explained that the copper tubes produced great internal stress during the drawing process. The purpose of heat treatment It is to eliminate the internal stress and increase the elongation, but if the heat treatment is not timely or the heat treatment process is improper, those copper tubes with micro-cracks themselves may crack under the action of internal stress. 2.2 Eddy current testing equipment With the development of eddy current testing technology, the current eddy current testing equipment generally adopts the impedance plan analysis method. The manufacturer's eddy current testing equipment adopts the A-scan analysis method. The defect signal detected by the eddy current on the screen is displayed in one dimension, and the influence of the eddy current field on the impedance of the probe coil is a vector, including the change of the resistance and reactance components, which is a two-dimensional information that is amplitude and phase angle. When the eddy current field passes through defects located at different depths from the surface, the mode and phase of the eddy current signal are also different. Obviously, the disadvantage of one-dimensional display is that the defects that are not harmful (shallow and large) will generate large signals, so that , a defect with a large hazard (deep and small area) will generate a small signal, so that a defect with a large hazard will be missed because of its small area. 2.3 Eddy current testing process In the eddy current testing process, the copper tubes are mechanically conveyed, and the unqualified copper tubes will be automatically separated. The principle is that when the defect signal exceeds the set waste judgment line, the separation function will act. However, when the copper tube enters and leaves the detection coil, the end will generate a strong signal, which far exceeds the set waste judgment line. In order to realize the automatic separation function of the unqualified copper tube, a set of The terminal signal delay function device, the general delay time is 0.2s.

If you are sourcing for product development or manufacturing operations, you won't miss Beijing Sincerity Automatic Equipment Co., Ltd's list of offer.

Beijing Sincerity Automatic Equipment Co., Ltd is proud to be recognized as some of the most important and influential providers for global customers.Visit us at Sincerity Flow Meter.

Beijing Sincerity Automatic Equipment Co., Ltd has been making a name for itself as a producer of some of the finest in the China, and it has been singing its praises for some time.

The major classifications of are u shape coriolis mass flow meter, endress hauser ultrasonic flow meter, endress hauser coriolis mass flow meter and tuning fork liquid density meter machines.

Natural has the distinct rosemount vortex flow meter which is irreplaceable.