Polyurethane sleeve, Dnepropetrovsk region.

Polyurethane sleeves are transparent, flexible tubes with a metal spiral soldered into their wall. Metal — spring steel or steel covered with copper. The second option is better. There are also two ways of producing such sleeves: by gluing the walls and soldering them. The process of gluing with the help of a special glue is mainly used. The wall thickness of polyurethane sleeves is from 0.4 mm to 3 mm, but there are also special polyurethane pipes with a wall thickness of up to 5 mm. The thickness is selected in accordance with the operating conditions.
(//tractor-service.com)
When using light powders,hose with a wall thickness of 0.4 mm is suitable. And in the case of a woodworking four-sided machine, it is better to buy sleeves made of polyurethane with a thicker wall - from 0.9 to 1.2 mm. If it isgrain or fraction, then a sleeve with a wall thickness of 2 or 2.5 mm is needed.
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