The eccentric reducer is internally cut at the ends of the nozzle, and is generally used for horizontal liquid pipes. When the eccentric pipe reducer is cut upward, it is called top flat installation. It is generally used for pump inlet, which is good for exhausting. The cut point is down to the bottom. It is generally used for adjusting the valve installation and using the drain.
The concentric reducer facilitates fluid flow and has less interference with the fluid flow regime when the diameter is reduced, so the gas and the vertically flowing liquid conduit use concentric reducer diameter reduction. Because the eccentric reducer is flat on one side, it is good for exhausting or draining, which is convenient for driving and overhauling. Therefore, the horizontally installed liquid pipeline generally uses an eccentric reducer. The roundness of the reducer shall not be greater than 1% of the outer diameter of the corresponding end, and the allowable deviation shall be ±3 mm; the allowable deviation of the reducer size shall comply with the provisions of Table 4.2.2-3.
The flowmeter of the corresponding caliber can be selected according to the actual flow rate of the process pipeline corresponding to the flow rate in the above table, and the flowmeter with the same caliber specification as the process pipeline can be selected as much as possible. The inlet of the pump inlet reducer should be installed so that the gas does not accumulate at the variable diameter to avoid cavitation due to improper installation. When the horizontal inlet pipe of the pump is reduced in diameter, an eccentric reducer should be used. When the pipe is pumped horizontally from bottom to top, the reducer should be "flat"; when the pipe is pumped horizontally from top to bottom, the reducer should be "bottom flat" to prevent gas from being at the pump inlet reducer. Accumulation, eccentric reducers are also installed in a "top flat" manner, even if the pipe is pumped horizontally from top to bottom. The pump that transports the medium with impurities at the end or side suction, when the suction speed is lower than the sedimentation speed of the impurities, the diameter of the reducer should be the same as the diameter of the nozzle that is inserted into the tank.
The stress distribution of the reducer:
The bending moment caused by the area pressure difference at the end of the different diameter tube causes the big end to be relatively open and the small end to shrink relative to each other.
The standard of the reducer:
There are two main systems for the international pipe flange standard, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by the American ANSI pipe flange. In addition, there are Japanese JIS pipe flanges, but they are generally only used for public works in petrochemical plants, and have little impact internationally. Now introduce the national pipe flanges as follows:
European system pipe flange represented by Germany and the former Soviet Union
American system pipe flange standard, represented by ANSI B16.5 and ANSI B 16.47
British and French pipe flange standards, the two countries have two casing flange standards.
In summary, the internationally accepted pipe flange standard can be summarized as two different, non-interchangeable pipe flange systems: a European pipe flange system represented by Germany; the other is represented by the United States. American pipe flange system.
IOS7005-1 is a standard promulgated by the International Organization for Standardization in 1992. This standard is actually a standard for pipe flanges that combines two series of pipe flanges from the United States and Germany.