codziennosc: Cryopump

Evidence: 100 • authority: 72

A cryopump or a "cryogenic pump" is a vacuum pump that traps gases and vapours by condensing them on a cold surface, but are only effective on some gases. The effectiveness depends on the freezing and boiling points of the gas relative to the cryopump's temperature. They are sometimes used to block particular contaminants, for example in front of a diffusion pump to trap backstreaming oil, or in front of a McLeod gauge to keep out water. In this function, they are called a cryotrap, waterpump or cold trap, even though the physical mechanism is the same as for a cryopump. Cryotrapping can also refer to a somewhat different effect, where molecules will increase their residence time on a cold…

Evidence: 42 • authority: 80

Trap for Use with Oil Diffusion Pump

Evidence: 42 • authority: 80

LINE RECORDER MASS SPECTROMETER OPERATION WITH AN OIL DIFFUSION PUMP AND CARBON TRAP

Evidence: 42 • authority: 72

In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases (hydrogen, oxygen, and nitrogen) into a liquid or solid. The most common objective is to prevent vapors being evacuated from an experiment from entering a vacuum pump where they would condense and contaminate it. Particularly large cold traps are necessary when removing large amounts of liquid as in freeze drying. Cold traps also refer to the application of cooled surfaces or baffles to prevent oil vapours from flowing from a pump and into a chamber. In such a case, a baffle or a section of pipe containing a number of cooled vanes, will be attached to the inlet of an existing pumping system.…

Evidence: 42 • authority: 72

Diffusion pumps are high-vacuum pumps that use high-speed vapor jets to direct gas molecules to the exhaust. Invented by Wolfgang Gaede in 1915, they are used to produce high and ultra-high vacuums. Because they cannot discharge directly into the atmosphere, they require a mechanical backing pump. The original design used mercury as the working fluid. The design was subsequently improved by Irving Langmuir. Modern diffusion pumps typically use silicone, hydrocarbon, or polyphenyl ether oils as working fluids. A major disadvantage of diffusion pumps is the tendency of the working fluid to backstream into the vacuum chamber, potentially contaminating sensitive equipment.