Patent ID: 8628238

Claim:
An apparatus for use as an evaporation or boil-off flow measuring device for determining thermal performance of a testing material, comprising: a cold mass assembly comprising: an inner vessel having a top, a bottom, a sidewall defining a testing chamber, and a sidewall for receiving a testing material, an upper guard chamber positioned at the top of the inner vessel, and a lower guard chamber positioned at the bottom of the inner vessel; an outer vacuum chamber enclosing the inner vessel and the testing material; a plurality of liquid conduits for receiving a liquid refrigerant having a normal boiling point below ambient temperature and for venting gas, each of the plurality of liquid conduits communicating through the outer vacuum chamber to a respective one of the testing chamber, the upper guard chamber, and the lower guard chamber; and a system of heater elements mounted on a sleeve mounted inside the outer vacuum chamber to provide warm temperature control.