Process for making a probe sheet

Claim 1

A method of manufacturing a disposable sheath for a temperature sensing probe comprising the steps of producing a tapered mandrel having the interior shape of the sheath to be produced; positioning said mandrel to be in a cavity shaped to conform to the outer shape of the sheath to be produced such that said mandrel is spaced a distance from the cavity wall corresponding to the desired wall thickness of the sheath, the distance between the tapered mandrel and the cavity wall adjacent to the small end of the mandrel is not larger than about 0.012 inch, the distance at the large end of the mandrel is at least about 0.039 inch and the distance at the small tip end of the mandrel is less than about 0.002 inch; injecting a suitable plastic selected from the group consisting of styrene, polypropylene and polyethylene into the space between the cavity and the mandrel at the tip end of the sheath through an orifice having a diameter of from 0.007 inch to 0.021 inch; cutting off flow through the orifice; and withdrawing the mandrel from the orifice while the plastic is in a moldable condition whereby the wall thickness adjacent a closed tip of the sheath is drawn down and the tip is fully enclosed said wall thickness at the top being such that rapid heat transfer will be obtained therethrough.

Claim 2

A method of manufacturing a disposable sheath for a temperature sensing probe comprising the steps of producing a tapered mandrel having the interior shape of the sheath to be produced; positioning said mandrel to be in a cavity shaped to conform to the outer shape of the sheath to be produced such that said mandrel is spaced a distance from the cavity wall corresponding to the desired wall thickness of the sheath, the distance between the tapered mandrel and the cavity wall adjacent to the small end of the mandrel is not larger than about 0.012 inch, the distance at the large end of the mandrel is at least about 0.039 inch and the distance at the small tip end of the mandrel is less than about 0.002 inch; injecting a suitable plastic selected from the group consisting of styrene, polypropylene and polyethylene into the space between the cavity and the mandrel at the tip end of the sheath through an orifice having a diameter of from 0.007 inch to 0.021 inch; cutting off flow through the orifice; and withdrawing the mandrel from the orifice while the plastic is in a moldable condition whereby the wall thickness adjacent a closed tip of the sheath is drawn down and the tip is fully enclosed said wall thickness at the top being such that rapid heat transfer will be obtained therethrough.