INTERNAL PRESSURE CHANGEABLE TYPE PRESSURE CAP AND AN AIRTIGHT CONTAINER THEREFOR

摘要

According to the present invention, an internal pressure changeable type pressure cap comprises: a cap body (10) wherein a cap screw (20) is arranged in a certain section of an inner circumference; a first spring (40) to increase or decrease a valve opening pressure of a positive pressure valve (30) by increasing or decreasing a compressive strain in accordance to the increase or decrease of an engagement section of the cap screw (20); a second spring (60) to set a magnitude of a negative pressure applied to a negative pressure valve (50) connected to the positive pressure valve (30), wherein compressive strain of the first spring (40) can be adjusted to a length of a screw engagement section formed with a filler neck (120) of an airtight container (100); and in an elastic coefficient state of the first spring (40) by increasing or decreasing a valve opening pressure of the positive valve (30) to approximately 08-1.5 bar by changing the compressive strain, and an internal pressure changeable type pressure cap used for various types of different airtight containers (100).