Good triple point of water cells contain only pure water and pure water vapour. (There is almost no residual air left in them.) When a portion of the water is frozen correctly and water coexists within the cell in its three phases, the “triple point of water” is realised. Comtest has on offer Fluke Calibration’s 9210 Triple Point of Water (TPW) maintenance apparatus that provides built-in programming for the simple supercool-and-shake realisation and maintenance of the 5901B mini TPW cell. Simply insert the cell, enter the “freeze mode” through the front panel buttons, and in no time at all the 9210 will audibly alert the user that the mini cell may be removed. Shaking it will initiate the freezing portion of the water. On reinsertion of the cell, the program can be changed to “maintain mode” and then it’s 0,01°C for the balance of the day, with an uncertainty of only +0,0005°C.
Contact Comtest, Tel 010 595-1821, firstname.lastname@example.org
Source: EE plublishers