Patent ID: 8066497
Filing Date: 2011-11-29
Classification: F01C,F04C

Abstract:
1. A positive-displacement pump comprising: a first side surface; a second side surface; a contour ring including a first axial side and a second axial side mounted between the first and second side surfaces so that a chamber is formed defined by an inner surface of the contour ring, the first side surface and the second side surface and so the first axial side is adjacent to the first side surface and the second axial side is adjacent to the second side surface; a pump element situated within the chamber and rotatable between the first and second side surfaces; and a coating on at least one of the first side surface and the second side surface, the coating not extending beyond a radial abutting surface of at least one of the first axial side and the second axial side of the contour ring and is only provided in a subarea of the area of the at least one of the first side surface and the second side surface abutting the contour ring.