Market development and use: New insulating flange

Since reform and opening, with the socialist market economy, sustainable and stable development, gas pipeline construction business in the city increasing popularity of the application. On the gas pipeline construction and protection has become increasingly important, with pipes to match the increasing application of insulating flange. How to find a good insulation and low cost of insulating flange is particularly important, this paper presents a new structure, low cost and easy to use a new type of insulating flange.
An old structure and characteristics of insulating flange
Old-fashioned form of type Ⅰ insulating flange is between two pieces of welded flange gasket and installation of insulation in the fastening flange connecting bolt insulation kits to install insulated bolts and gasket composition. The structure of assembly drawing shown in Figure 1, the flange gasket material selection, oil resistant rubber insulation asbestos, neoprene rubber sheets, neoprene fabric-based boards and PTFE and other materials. Insulating sleeve and bolts bolt high strength insulating gasket phenolic cloth laminated board and pressure piping production. Its characteristics are: steel, good insulation, the need for specialized expertise to install the installation location, and high cost.
2 The development of new insulating flange
Our old structure was insulated flange type for improvement. In the city gas distribution projects, city gas distribution works for low pressure (PN ≤ 2.5MPa), PN ≤ 0.4MPa pressure pipe network to improve the characteristics. Transmission and distribution projects in the pipeline used to replace steel flange welded flange, flange gasket with PTFE insulation, oil resistant asbestos rubber sheets, neoprene and other materials, and the bolts fastening the insulation will be two sets of pads and insulation into one, and reduce the insulating cover half of the insulation made of high-intensity sets the overall style pad. Figure 2, will wear a set of pads steel flange bolt holes extending through insulating sleeve can Pad; to ensure cover pad aperture used for the original steel flange bolts requirements, so we made a special role in the Steel Plate Lan, became a new type of insulating flange after assembly, its structure shown installed in Figure 3,4. It can be installed separately, it can be installed to connect the valve; not only cost savings but also saving on-site installation location, is a simple application of a new type of insulating flange, and particularly low cost.
3 Principle and performance insulation
The working principle of insulating flange is insulated using insulating gaskets and flanges of high strength insulating cover gasket flange insulation electric insulation properties of insulation on both sides of the work carried out. According to engineering practice, we insulation of the insulated flange by "insulating flange design provides" (SY/T0516--1997) of the request and "buried steel pipeline cathodic protection parameters of test methods" (SYJ23- 86) in the test methods, test results show that: insulating spacer and the insulating sleeve pad fastening bolts work in insulation between the surface of the resistance value can meet the requirement.
4 Usage
Such cathodic protection insulating flange during the transmission and distribution networks, and in need of Louzhuang valve potential sub-plate (area) isolated buried pipe and valve to use the well. For underground transmission and distribution network of sub-pieces (regions) isolation can be more clearly grasp the film (District) pipeline cathodic protection situation; on the cathodic protection fragment (zone) to evaluate the cathodic protection for different processing conditions; When the adjacent slice (area) of the protection potential of the same (or similar) and to protect the potential demand, cross-section can be connected on both sides of the insulated flange unified protection; when the adjacent slice (area) protection potential difference is large and potential has not reach the required chip (area), it can not protect the potential required to reach film (area) for special treatment until it meets the requirements until later contiguous run.
5 applicability
Produced by the methods of insulating flange on the oil pressure PN ≥ 2.5MPa Tanaka, long distance pipeline, station, etc. still apply with the insulating flange. Just flange into the corresponding level of special flanges can be, to use exactly the same.
6 Conclusion
(1) the new insulating flange structure of the new species, applicability and low cost.
(2) It does not only apply to the city gas distribution projects in the electrical insulation isolation; but also for long-distance pipeline, set gas pipeline transmission and distribution station electrical insulation such as the need for isolated areas