Isotech Nitrogen Boiling Point Apparatus

Isotech nitrogen boiling point apparatus

Isotech nitrogen boiling point apparatus is specially designed to achieve and maintain the liquid/vapour equilibrium (boiling point) of nitrogen or argon. This is for calibrating thermometers on the international temperature scale of 1990. The boiling point apparatus is freestanding and cooled with liquid nitrogen or liquid argon, which must be provided by the user. Both fluids are suitable for this purpose. Liquid nitrogen is generally cheaper and more readily available than liquid argon.

The device does not require a mains connection. The boiling point apparatus remains indefinitely on the liquid/vapour balance of nitrogen (-195,798 °C) or argon (-185,8468 °C), provided that the gas used is topped up.

ITS-90 specifies the triple point of argon (-189.3442 °C), such as the lower end of the lung voice standard platinum resistance thermometer range. As a practical issue, the realization of this triple point is a costly and complicated process both in time and material.

Isotech Model 18205 comparator is designed for precisely this comparison calibration. It consists of a stainless steel Dewar, an internal equalization block with wells for three thermometers, top connections for filling and checking the level of coolant, a pressure relief valve and a manifold that can be used to thermally link the thermometers under test to the helium gas equalization block (optional).