Patent ID: 7776118

Claim:
A cap for hermetically sealing a receiver drier, the cap comprising: a cap body which includes a coupling portion formed along its outer circumference to be engaged with an opening of a tank of a receiver drier and a flange formed at its lower end portion; a filter including an engagement means that detachably couples the filter with the upper portion of the cap body, an inlet and an outlet to allow a working fluid passing therethrough, and a filter net formed along its circumference; and an O-ring installation means which includes an O-ring seating portion having one side opened along the circumference of an upper portion of the cap body and an O-ring supporting portion that is formed at lower end portion of the filter and closes the opened side of the O-ring seating portion so as to prevent the O-ring from being separated wherein the engagement means includes a protrusion formed at an upper end portion of the cap body and an insertion groove formed at a lower end portion of the filter to correspond to the protrusion, wherein the protrusion further includes a material reducing groove to reduce the amount of material, and wherein the lower end portion of the filter includes a discharge hole that communicates with the material reducing groove.