New type of insulating flange development and use

　Since the reform and opening up, along with our country socialist market economy steady development, pipeline gas business in the urban construction of the application of the growing popularity. For gas pipeline engineering construction and protection work is becoming more and more important, and the corresponding pipe insulation flange application more and more common. How to look for a kind of insulation performance is good, low cost of insulating flange appears especially important, this paper introduces a new structure, low cost, use agile and convenient new type of insulating flange. 1. The old insulation flange structure and characteristics of the old type I insulation flange structure is in two pieces of butt welding plane flanges with flange insulation gasket and fastening bolt on the insulation sleeve and insulation bolt gasket composition. The flange insulation gasket material choose oil resistant rubber asbestos board, chloroprene rubber, neoprene rubber sheet fabric base and ptfe etc materials manufacturing. Insulation bolt sets and bolt insulation gasket high strength of the phenolic laminated fabric swatch and compresses for control. Its characteristic is: good rigidity, insulation performance is stable, need to have special installation position special installation, cost is high. 2. The development of new type of insulating flange of our old insulation flange structure ShiYongXing improvement. In the city gas transmission and distribution engineering, city gas transmission and distribution engineering in low pressure (PN acuities were 2.5 MPa), the pipeline pressure PN acuities were 0.4 MPa on the characteristics of improvement. In the network transmission and distribution engineering using steel plane flange instead of butt welding plane flange, flange insulation gasket using teflon, oil resistant rubber asbestos sheet, neoprene rubber materials manufacturing, and fastening bolt insulation sleeve and insulation pad will combine into one, and shorten the insulation sleeve half make monolithic high strength insulation sleeve pad. Will wear cushion cover steel flange bolt hole to expand to wear insulation sleeve cushion; To ensure cushion cover inside aperture for raw steel flange used bolt requirements, so we make a special function of steel flange, after assembly became new insulation flange. It can be installed alone, also can be connected together with the valve installation; Not only saves the cost of the project, and save the installation position, is a simple and applicable new insulation flange, and the cost of special low. 3. Insulation principle and properties of insulating flange working principle is to use insulating flange, the insulation gasket and high strength insulation sleeve mat electric insulation property of insulating flange on both sides of the electric insulation to work. According to the engineering practice, we of the insulation flange insulation performance according to the insulation flange design technical regulations (SY/T0516-1997) and the related requirements of the buried steel pipeline cathodic protection parameters test method "(SYJ23-86) of the test method, test results show that the insulation gasket and fastening bolt insulation sleeve pad in insulating work between the surface resistance can meet the standard requirement. 4. Use this kind of insulating flange on the cathodic protection of pipeline network building and building valve place for potential dividing (area) the isolation of buried pipe valve used in well. For buried pipeline network of dividing (area) isolation can more clearly grasp the tablet (area) network of cathodic protection; On cathodic protection (area) dividing evaluation, according to different cathodic protection situation of processing; When adjacent piece (area) protection potential the same (or similar) and to reach the protection potential requirements, can be used across the insulation flange on both sides connected undertake unity protection; When adjacent piece (area) protection potential difference is bigger and can not reach the protection potential requirements of the tablet (area), but will reach protection potential requirements of the tablet (area) for special treatment to meet the requirements, so later shall run. 5. Strong applicability and the method of the production of insulating flange in oil and gas pressure PN was 2.5 MPa long pipeline, yard, etc used in the insulation flange is the same. Just put the flange to the corresponding level of special flange can, use the same method. 6. Conclusion (1) the new type of insulating flange structure new, applicability, low cost. (2) it is not only the city gas transmission and distribution engineering electric insulation isolation; But also for long distance pipeline, set gas pipeline and transmission and distribution station and the need for electrical insulating isolated places.