Double-disc reducer (concentric reducer flange / eccentric reducer flange)

Steel-plastic pipe fittings are also called plastic-steel composite pipe fittings. The main raw materials are seamless steel pipes and Q235 steel plates. They are welded after curling. After welding, grinding, sandblasting and other processes, the pipe fittings are sent to the spraying factory for pickling. After phosphating, plastic powder is sprayed on the inner and outer walls of the pipe fittings (called electrostatic spraying). After high-temperature drying at 230C-250C in the furnace, it is firmly attached to the inner and outer walls. The general coating thickness is between 0.2mm-0.3mm. This coating has good adhesion, strong corrosion resistance, strong acid and alkali resistance, smooth inside and outside of the pipe, and no adhesion to any substance, which effectively reduces the resistance during transportation.

Interface type: Both interfaces are flanges, but the diameters of the two flanges are different (one large and one small).

Use method:

Concentric reducer: Used for pipes that need to connect different pipe diameters but require center line alignment. Commonly used in vertical or horizontal pipes where the fluid state is not required.

Eccentric reducer:

Flat bottom: Used in horizontal pipes to keep the bottom elevation of the pipe consistent and prevent gas accumulation at the diameter change (such as the pump inlet).

Flat top: Used in horizontal pipes to keep the top elevation of the pipe consistent and prevent liquid from being retained at the diameter change (such as the drain pipe).

Side flat: Less common, used in special space restrictions.

Installation precautions:

Confirm type: Be sure to confirm whether it is concentric or eccentric (and the direction of eccentricity) before installation.

Flow direction: Pay attention to the flow direction arrow marked on the reducer (if any) or install according to the designed flow direction (usually from the large end to the small end to reduce resistance loss, but not absolutely).

Eccentric direction:

Horizontal installation: The "flat edge" (straight edge) of the eccentric reducer must be installed strictly in accordance with the design requirements (top flat, bottom flat or side flat). Reverse installation is absolutely not allowed! Otherwise, the meaning of the eccentric design will be lost, and even gas or liquid blockage will occur.

Vertical installation: Concentric reducers are usually used. If eccentricity is used, the design intent must be clear (such as side flat to avoid obstacles).

Flange connection: Follow the standard flange connection precautions (flange face, gasket, bolts, centering, torque). Note that the center circle diameters of the bolt holes of the two flanges may be different (flanges of corresponding pressure levels need to be matched).

Support: Additional stress may be generated at the reducer, and good support should be provided near the reducer.