International standard for flange in flange tubular heater
The flange size of flange type electric tubular heater is generally in accordance with international standards, which is usually expressed by DN. In the international standard flange, according to the different pressure, it is divided into 1.mpa and 2.0MPa flange with different pressure index. The unit of flange DN in flange type electric heating pipe is MPa in international system of units and kgf / cm2 in engineering unit system.
Generally speaking, the international standard flange includes the following parameters: Generally speaking, the parameters include the outer diameter of flange plate, the diameter of hole center circle, the diameter of bolt hole, the number of bolt holes, the thickness of flange, the theoretical weight, etc. The outer diameter of the heating pipe with seamless steel pipe is indicated by the letter D, followed by the dimension and wall thickness of the external diameter. For example, the wall thickness of seamless steel pipe with outer diameter of 108 is 5mm, which is indicated by d108 * 5, which is shown in the design drawing 1 The nominal diameter is generally expressed by nominal diameter. The nominal diameter is a standard artificially specified for the convenience of design, manufacture and maintenance. Compared with the nominal diameter, it is the specification name of the pipe (or pipe fitting). The nominal diameter of the pipe in the flange type electric heating pipe is not equal to its inner diameter and outer diameter. For example, the seamless steel pipe with nominal diameter of 100 mm is 102 * 5, 108 * 5, etc., 108 is the outer diameter of the pipe, and 5 is the wall of the pipe Therefore, the inner diameter of the steel pipe is (108 * 5-5) = 98mm, but it is not exactly equal to the difference between the outer diameter of the steel pipe minus twice the wall thickness. It can also be said that the nominal diameter is close to the inner diameter, but not equal to the inner diameter The nominal diameter is used in the design drawings for the specification name of a pipe diameter. The purpose is to determine the structural dimensions and connecting ruler of pipes, pipe fittings, valves, flanges, gaskets, etc. in the flange type electric heating pipe according to the nominal diameter The nominal diameter is indicated by the symbol DN. If the outer diameter is used in the design drawing, the pipe specification comparison table should also be made to indicate the nominal diameter and wall thickness of the pipe in a flange type electric heating pipe.
When designing and manufacturing the flange electric tubular heater, the customer is generally required to confirm whether the size of the flange plate is the national standard flange. If it is not, the diameter and quantity of the hole center circle, the diameter and quantity of the bolt hole, as well as the thickness of the flange should be confirmed. When selecting the heating pipe, the diameter and quantity of the heating pipe should be considered Considering the diameter of the pipe and the number of flange plates, the appropriate size should be selected.
