Temperature sensing apparatus

An apparatus for indicating a condition of its environment and adapted for use in a high temperature oven environment and alternatively for immersion in water, comprising:

• a body enclosing a chamber, said body including a wall having an opening therethrough, said wall having an interior surface and an exterior surface;
• means in said chamber for indicating the condition of the environment in which said apparatus is positioned;
• and
• a valve mounted in said opening, said valve comprising a resilient interior lip portion overlying said interior surface adjacent said opening, a resilient exterior lip portion overlying said exterior surface adjacent said opening, and a resilient membrane portion separating said chamber from said environment and having a slit therethrough, wherein pressure in said chamber is relievable through said slit.

A temperature sensing apparatus for displaying temperatures in an environment where the apparatus is positioned, said apparatus being exposed to periodic temperature fluctuations that include high temperatures, said apparatus comprising:

• a body, said body enclosing a chamber, said body including a wall bounding said chamber having an opening therethrough, said wall having an interior surface and an exterior surface;
• display means on said body for displaying the temperature in the environment wherein said body is positioned;
• and
• pressure relief means mounted in said opening for reliving pressure in said chamber to said environment when said pressure in said chamber exceeds a pressure level, said pressure relief means comprising a resilient exterior lip means for overlying said exterior surface adjacent said opening, a resilient interior lip means for overlying said interior surface adjacent said opening, and a membrane means for separating said chamber from said environment and for closing said opening, said membrane means including a perforation means therethrough for opening said membrane means through said perforation means when said pressure level is exceeded and for closing said membrane means when said pressure has dropped below said pressure level.