Heat activated vent

摘要

A heat activated vent for releasing an excess internal pressure in a container which pressure is accompanied by an abnormal rise in an internal temperature of the container uses a spring to store sufficient energy to propel a barb or spike to pierce a thin diaphragm. The spring is retained within a hollow vent housing between an end wall of the housing and a movable plate located within the housing and carrying a diaphragm piercing upright barb. A pierceable thin diaphragm is positioned adjacent to the sharp end of the barb and is arranged to provide a leak proof seal across an open end of the housing. The barb carrying plate is normally retained in a position wherein the barb is spaced from the diaphragm by a rigid pin extending between the plate and the housing and having a lower coefficient of thermal expansion than the housing. In one embodiment of the invention, one end of the pin projects through a hole in the plate and has a radially expanded head which engages the barb carrying plate. The other end of the pin is retained in a hole in the vent housing as a result of a shrink fit in the hole in the housing. The expanded head of the pin may be located on the outside surface of the vent housing while the body of the pin passes through a hole into the vent housing and is retained by a shrink fit in a hole in the plate.