Scroll type fluid displacement apparatus with surface treated spiral element

DETAILED DESCRIPTION It is a primary object of this invention to provide an improved scroll type fluid displacement apparatus which provides excellent sealing and anti-wearing.
It is another object of this invention to provide a scroll type fluid displacement apparatus in which increased dimensional accuracy in manufacturing the scrolls can be achieved.
It is still another object of this invention to provide a scroll type fluid displacement apparatus in which friction between the spiral elements is reduced.
It is still another object of this invention to provide a scroll type fluid displacement apparatus which is simple in construction and light in weight to achieve the above described objects.
A scroll type fluid displacement apparatus according to this invention includes a pair of scrolls each comprising a circular end plate and a spiral wrap extending from one side of the circular end plate.
The spiral elements interfit at an angular and radial offset to make a plurality of line contacts to define at least one pair of sealed off fluid pockets.
A driving mechanism is operatively connected to one of the scrolls to effect the orbital motion of one scroll while simultaneously preventing rotation.
As a result, the volume of the fluid pockets changes due to the orbital motion of the one scroll.
Both scrolls are formed of aluminum or an aluminum alloy, and at least the orbiting scroll, is treated by alumite, but only after its surface is finished by electrolytic polishing or chemical polishing.
Further objects, features and other aspects of this invention will be understood from the detailed description of the preferred embodiments of this invention referring to the annexed drawings.