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The Kelvin water dropper, invented by Scottish scientist William Thomson (Lord Kelvin) in 1867, [1] is a type of electrostatic generator. Kelvin referred to the device as his water-dropping condenser. The apparatus is variously called the Kelvin hydroelectric generator, the Kelvin electrostatic generator, or Lord Kelvin's thunderstorm.
Nitrogen generators are used in hypoxic air fire prevention systems to produce air with a low oxygen content which will suppress a fire. To prevent corrosion, nitrogen generators are used in place of or in conjunction with a compressed air system to provide supervisory nitrogen gas in place of air for dry pipe and pre-action fire sprinkler systems.
The temperature of liquid nitrogen can readily be reduced to its freezing point −210 °C (−346 °F; 63 K) by placing it in a vacuum chamber pumped by a vacuum pump. [2] Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of ...
When performed on a larger scale, this technique is called freeze-drying, and the cold trap is referred to as the condenser. Cold traps are also used in cryopump systems to generate hard vacua by condensing the major constituents of the atmosphere (nitrogen, oxygen, carbon dioxide and water) into their liquid or solid forms.
Nitrogen, argon, helium and other inert gases are commonly used. To maximize this process called sparging , the solution is stirred vigorously and bubbled for a long time. Because helium is not very soluble in most liquids, it is particularly useful to reduce the risk of bubbles in high-performance liquid chromatography (HPLC) systems.
With this variant of PSA developed for use in laboratory nitrogen generators, nitrogen gas is produced into two steps: in the first step, the compressed air is forced to pass through a carbon molecular sieve to produce nitrogen at a purity of approximately 98%; in the second step this nitrogen is forced to pass into a second carbon molecular ...
Two procedures for degassing are common. The first is known as freeze-pump-thaw — the solvent is frozen under liquid nitrogen, and a vacuum is applied. Thereafter, the stopcock is closed and the solvent is thawed in warm water, allowing trapped bubbles of gas to escape. [4] The second procedure is to simply subject the solvent to a vacuum.
In an incident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were sealed with brass plugs. As a result, the tank failed catastrophically and exploded. [3] Secondly, if a dewar is left open to the air for extended periods, atmospheric chemicals can condense or freeze on contact with the cryogenic material.