Patent ID: 8636484
Filing Date: 2014-01-28
Classification: F04B

Abstract:
1. A bellows plunger, comprising: a tubular body having a first closed end integrally formed as a single piece with the tubular body and an opposite, second open end, the tubular body comprising a side wall having a shape defining at least one ridge extending continuously and helically about a longitudinal axis of the tubular body from a location proximate the first closed end to a location proximate the second open end, wherein, upon formation of the tubular body, the side wall of the tubular body has an inner surface defining a valley extending continuously and helically about the longitudinal axis of the tubular body, at least one of a width and a depth of the valley increasing in a direction extending from the location proximate the first closed end to the location proximate the second open end; an insert comprising a cavity defined by a closed end wall, a radial side wall, and an inner wall parallel to the closed end wall, the insert disposed within the first closed end of the tubular body; and an opening extending through the inner wall and providing fluid communication between an interior region of the tubular body and the cavity.