Apparatus for differential thermal analysis

Claim 2

Apparatus for differential thermal analysis, which comprises a cylindrical block of thermally conductive material having a longitudinal central cylindrical cavity extending axially from one end of the block into but not through The block, means for introducing discrete slugs of a liquified gas into the central cavity comprising two concentric tubes mounted in the cavity by means of a gastight seal, both tubes being open at the ends inside the cavity, the inner tube extending further into the cavity than the outer tube and being connected at its outer end by means of small bore heat-insulating tubing to a sealed reservoir of liquified gas and the outer tube being connected at its outer end by means of small bore tubing to a vent valve, a plurality of longitudinal cavities around the central cavity and extending from the same end of the block as the central cavity into but not through the block, and means for measuring the temperature in each of the radially disposed cavities.

Claim 3

Apparatus for differential thermal analysis, which comprises a block of thermally conductive material having a longitudinal central cavity extending axially from one end of the block into but not through the block; a sealed reservoir for liquified gas having an outlet and a valve in said outlet for controlling flow of liquified gas out of said reservoir; means for introducing discrete slugs of a liquified gas into the central cavity comprising two concentric tubes mounted in the cavity by means of a gastight seal, both tubes being open at the ends inside the cavity, the inner tube extending further into the cavity than the outer tube, flexible small bore heat-insulating tubing connecting said reservoir outlet valve and said outer end of said inner tube and providing a path for flow of liquified gas from said reservoir to said central cavity through said inner tube, the thickness and thermal conductivity of the tubing wall being such that the heat transfer from ambient atmosphere to the bore wall causes partial vaporization of liquified gas passing therethrough, and a vent valve for controlling flow of vaporized liquified gas from said central cavity through said outer tube, said vent valve being connected to the outer end of the outer tube by flexible small bore heat-insulating tubing, whereby closing or opening of said vent valve decreases or increases, respectively, the pressure differential between the sealed reservoir and the central cavity; a plurality of longitudinal cavities around the central cavity and extending from the same end of the block as the central cavity into but not through the block; and means for measuring the temperature in each of the radially disposed cavities.

Claim 4

Apparatus for differential thermal analysis, which comprises a block of thermally conductive material having a longitudinal central cavity extending axially from one end of the block into but not through the block; a sealed reservoir for liquified gas having an outlet and a valve in said outlet for controlling flow of liquified gas out of said reservoir; means for introducing discrete slugs of a liquified gas into the central cavity comprising two concentric tubes mounted in the cavity by means of a gastight seal, both tubes being open at the ends inside the cavity, the inner tube extending further into the cavity than the outer tube, flexible small bore heat-insulating tubing connecting said reservoir outlet valve and said outer end of said inner tube and providing a path for flow of liquified gas from said reservoir to said central cavity through said inner tube, the thickness and thermal conductivity of the tubing wall being such that the heat transfer from ambient atmosphere to the bore wall causes partial vaporization of liquified gas passing therethrough, and a vent valve for controlling flow of vaporized liquified gas from said central cavity through said outer tube, said vent valve being connected to the outer end of the outer tube by flexible small bore heat-insulating tubing, whereby closing or opening of said vent valve decreases or increases, respectively, the pressure differential between the sealed reservoir and the central cavity; a plurality of longitudinal cavities around the central cavity and extending from the same end of the block as the central cavity into but not through the block; and means for measuring the temperature in each of the radially disposed cavities.

Claim 5

Apparatus according to claim 2, wherein said small bore tubing has a bore of about 2 mm., a wall thickness of about 1 mm. and is made of polyvinyl chloride.

Claim 6

Apparatus according to claim 2, including means for heating said block.

Claim 7

Apparatus according to claim 4, wherein said small bore tubing has a bore of about 2 mm., a wall thickness of about 1 mm. and is made of polyvinyl chloride.

Claim 8

Apparatus according to claim 5, wherein said block is a cylindrical block, said central cavity is a cylindrical cavity, and three longitudinal cavities are provided symmetrically disposed around said central cavity.