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An electric discharge as a trap for diffusion-pump vacuum systems
Classified abstracts 584--597 consistently poor results. The configurations involving barium plating gave results placed between these extremes. (Author) T W Flafley, Report NASA-TN-D-2304, Goddard Space Flight
Center, Greenbelt, Md, USA, June 1964.
24. Valves 24 : 42 584. Glass stopcock for the metering of gases. (USSR) Conventional stopcocks give a non-uniform gas flow owing to interaction between the gas and the lubricant, the latter gradually blocking the passage. A new design incorporates a partly-lubricated stopper: the upper third of its length is lubricated for hermetic purposes, while the rest is unlubricated and serves as a " c h o k e " system. With the help of this new design a stable and even gas flow can be achieved, the flow being almost linearly dependent on the angle of rotation of the stopper. A I Subbotin, ZavodLabor, 11, 1965, 1421. 24 : 23 585. Vacuum valves without bellows. (USSR) The construction of medium- and high-vacuum valves not involving metal bellows and ground joints is described. The valve seal consists of vacuum-rubber hosing operating in both tension and compression, which can be replaced as required without dismantling the valve. Valves of this kind have been used successfully in X-ray spectrographs and vacuum-evaporation systems; they are simpler and more reliable than conventional bellows. B Ya Petrenko and A M Zherdev, Pribory i Tekh Eksper, 6, Nov-Dec
1965, 207, (in Russian). 24 586. Adjustable high vacuum stopcock valves. (USA) New high vacuum stopcock valves are made of hard borosilicate glass with a Teflon stem and Viton O-rings. Needle-type valves have special threads inside the knurled handle and on the valve stem to facilitate opening and closing. Opening can be adjusted from fine to coarse. Anon, Scientific Glass Apparatus Co Ltd, Bloomfield, N J, USA. 24 587. Flow characteristics of control valves. (Great Britain) Measurement of air flow rate through each of a series of 2 in. control valves with valve diameters of ¼ in., ½ in., and ¼ in. were obtained at various valve settings, and for various pressure ratios ranging from no-flow to choked-flow conditions. T J Black and A Brown, The Engineer, Nov 1965, 874-876.
25. Baffles, traps and refrigeration equipment 25 : 17
" C r e a c h e r " cryogenic refrigerator. See abstract n u m b e r 523. 25 588. New apparatus. Thermoelectric vacuum traps. (USSR) A new form of vacuum trap based on thermoelectric cooling is described. These traps are designed to replace liquid-nitrogen traps for freezing out the residual vapour of the working liquid in oil-jet diffusion pumps. Arrangements for using these in connection with a n u m b e r of standard pumps are described. The construction is such that the traps may easily be removed and replaced without major dismantling. The vacuum attainable by using the new traps is comparable with that given by liquid nitrogen and in various other respects the new traps are superior. The principal parameters of typical thermoelectric traps are tabulated. Anon, Pribory i Tekh Eksper, 6, Nov-Dec 1965, 223, (in Russian). 25 : 21 589. High-vacuum traps for oil-vapour diffusion pumps. (USSR) Experiments on the escape of oil from oil-vapour diffusion pumps through various types of condensation trap are described. Methods of protecting the evacuated volume from oil vapour (water traps, nitrogen traps, etc) are compared and discussed. Because of the high rate of oil evaporation from the surface, water-cooled traps can be made fairly highly conducting; they also have various other advantages. Combinations of traps, eg, water q- nitrogen, are valuable for special purposes. N M Baryshova, Pribory i Tekh Eksper, 6, Nov-Dec 1965, 139, (in
Russian). 25 590. Vacuum traps. (USA) A survey of available vacuum baffles and traps. 13 Brown, Instrums and Control System, 38 (11), Nov 1965, 95-96.
25 591. An electric discharge as a trap for diffusion-pump vacuum systems. (USA) An electric discharge is used as a trap for a diffusion pump using DC-704 silicon oil pump fluid. The discharge cracks the pump-fluid vapour thus taking it out of the system. In the process much hydrogen and some lighter gases are evolved. R O Adams, US At Energy Comm, RFP-572, 1965, 9pages. 25 592. Cryomaster. (USA) "Cryomaster" is an integrated system for maintaining and controlling low temperatures without using liquid cryogens. The unit permits easy and rapid cryogenic temperature measurements without previously required liquids, storage dewars, working dewars, or transfer lines. Any selected temperature within the range 25 to 300°K can be attained, and accuracy can be maintained to ±0.01 ° K. Temperature is varied with a single control in the Cryomaster, and its refrigerator engine is charged at the factory with helium gas - - n o further liquids or gases are required. Anon, Malaker Corp, High Bridge, N J, USA. 25:16 593. A simple zeolite trap. ( U S S R ) A zeolite trap enabling a vacuum of 10 -7 tort to be obtained in vacuum systems without the use of liquid nitrogen is described. The main features of the trap are based on that of Stack and Knauer (Rev Scient Instrum, 37, 1963, 438), except that artificial zeolite of the type available in the USSR was used. Initial faults in the vacu u m system as yet prevent the full potentialities of the zeolite from being realized. One reference. B A Gerasimov, Pribory i Tekh Eksper, 5,243.
26. Automatic protective and control equipment 26:33 Control of switching in the vacuum system of a mass spectrometer. See abstract n u m b e r 640. 26:31 594. Vaeuum switches for use in eontaetors. (Great Britain) Anon, AE1, 5 (6), Nov-Dec 1965, 311-315.
27. Leak detectors and leak detection 27 : 22
Residual gas analysis by mass spectrometry. See abstract n u m b e r 560. 27 : 22 595. Muss-spectrometric leak detector of high sensitivity (MKh1102).
(USSR) A new type of mass-spectrometric leak detector (MKh1102) is described. Apart from its high sensitivity, this has a n u m b e r of other advantages over conventional types, including a linear characteristic and simple calibration, low background, and great stability with respect to time. The measuring system consists of four units: de amplifier, analyzer supply system, pressure gauge, and external control, each situated in its own chassis. The technological parameters of the new system are tabulated for comparison alongside those of the PTI-6 leak detector. Three references. V A Pavlenko et al, Pribory i Tekh Eksper, 5, 190. 27 : 56 596. Portable leak detector. (USA) Portable mass-spectrometer type helium leak detector will, according to manufacturer, detect one part helium in 10 million parts air. Assembly comprises gun-electrometer optics module in stainlesssteel housing, and portable solid-state electronics module that contains all controls and power supply. Anon, Mikros Div of Varian Associates, Capitol Highway, Portland,
Oregon. 27 597. Automatic leak tests. (USA) Leak test stations have a single, two-position switch that automatically controls the entire test cycle, making it simple for anyone to operate. A sensitivity of 5 x 10 -1= (Model MD-120A) and 1 x 10-11 std. cc/sec (Model MD-100A) is reported at full pumping speed. Testing cycle is started by moving the switch to "test" position; at termination, the switch is moved to "rest" position. The machine then automatically prepares itself for the next cycle. Anon, Vacuum Instruments Co, Stepar Place, Hungington, Station,
NY.
225
Center, Greenbelt, Md, USA, June 1964.
24. Valves 24 : 42 584. Glass stopcock for the metering of gases. (USSR) Conventional stopcocks give a non-uniform gas flow owing to interaction between the gas and the lubricant, the latter gradually blocking the passage. A new design incorporates a partly-lubricated stopper: the upper third of its length is lubricated for hermetic purposes, while the rest is unlubricated and serves as a " c h o k e " system. With the help of this new design a stable and even gas flow can be achieved, the flow being almost linearly dependent on the angle of rotation of the stopper. A I Subbotin, ZavodLabor, 11, 1965, 1421. 24 : 23 585. Vacuum valves without bellows. (USSR) The construction of medium- and high-vacuum valves not involving metal bellows and ground joints is described. The valve seal consists of vacuum-rubber hosing operating in both tension and compression, which can be replaced as required without dismantling the valve. Valves of this kind have been used successfully in X-ray spectrographs and vacuum-evaporation systems; they are simpler and more reliable than conventional bellows. B Ya Petrenko and A M Zherdev, Pribory i Tekh Eksper, 6, Nov-Dec
1965, 207, (in Russian). 24 586. Adjustable high vacuum stopcock valves. (USA) New high vacuum stopcock valves are made of hard borosilicate glass with a Teflon stem and Viton O-rings. Needle-type valves have special threads inside the knurled handle and on the valve stem to facilitate opening and closing. Opening can be adjusted from fine to coarse. Anon, Scientific Glass Apparatus Co Ltd, Bloomfield, N J, USA. 24 587. Flow characteristics of control valves. (Great Britain) Measurement of air flow rate through each of a series of 2 in. control valves with valve diameters of ¼ in., ½ in., and ¼ in. were obtained at various valve settings, and for various pressure ratios ranging from no-flow to choked-flow conditions. T J Black and A Brown, The Engineer, Nov 1965, 874-876.
25. Baffles, traps and refrigeration equipment 25 : 17
" C r e a c h e r " cryogenic refrigerator. See abstract n u m b e r 523. 25 588. New apparatus. Thermoelectric vacuum traps. (USSR) A new form of vacuum trap based on thermoelectric cooling is described. These traps are designed to replace liquid-nitrogen traps for freezing out the residual vapour of the working liquid in oil-jet diffusion pumps. Arrangements for using these in connection with a n u m b e r of standard pumps are described. The construction is such that the traps may easily be removed and replaced without major dismantling. The vacuum attainable by using the new traps is comparable with that given by liquid nitrogen and in various other respects the new traps are superior. The principal parameters of typical thermoelectric traps are tabulated. Anon, Pribory i Tekh Eksper, 6, Nov-Dec 1965, 223, (in Russian). 25 : 21 589. High-vacuum traps for oil-vapour diffusion pumps. (USSR) Experiments on the escape of oil from oil-vapour diffusion pumps through various types of condensation trap are described. Methods of protecting the evacuated volume from oil vapour (water traps, nitrogen traps, etc) are compared and discussed. Because of the high rate of oil evaporation from the surface, water-cooled traps can be made fairly highly conducting; they also have various other advantages. Combinations of traps, eg, water q- nitrogen, are valuable for special purposes. N M Baryshova, Pribory i Tekh Eksper, 6, Nov-Dec 1965, 139, (in
Russian). 25 590. Vacuum traps. (USA) A survey of available vacuum baffles and traps. 13 Brown, Instrums and Control System, 38 (11), Nov 1965, 95-96.
25 591. An electric discharge as a trap for diffusion-pump vacuum systems. (USA) An electric discharge is used as a trap for a diffusion pump using DC-704 silicon oil pump fluid. The discharge cracks the pump-fluid vapour thus taking it out of the system. In the process much hydrogen and some lighter gases are evolved. R O Adams, US At Energy Comm, RFP-572, 1965, 9pages. 25 592. Cryomaster. (USA) "Cryomaster" is an integrated system for maintaining and controlling low temperatures without using liquid cryogens. The unit permits easy and rapid cryogenic temperature measurements without previously required liquids, storage dewars, working dewars, or transfer lines. Any selected temperature within the range 25 to 300°K can be attained, and accuracy can be maintained to ±0.01 ° K. Temperature is varied with a single control in the Cryomaster, and its refrigerator engine is charged at the factory with helium gas - - n o further liquids or gases are required. Anon, Malaker Corp, High Bridge, N J, USA. 25:16 593. A simple zeolite trap. ( U S S R ) A zeolite trap enabling a vacuum of 10 -7 tort to be obtained in vacuum systems without the use of liquid nitrogen is described. The main features of the trap are based on that of Stack and Knauer (Rev Scient Instrum, 37, 1963, 438), except that artificial zeolite of the type available in the USSR was used. Initial faults in the vacu u m system as yet prevent the full potentialities of the zeolite from being realized. One reference. B A Gerasimov, Pribory i Tekh Eksper, 5,243.
26. Automatic protective and control equipment 26:33 Control of switching in the vacuum system of a mass spectrometer. See abstract n u m b e r 640. 26:31 594. Vaeuum switches for use in eontaetors. (Great Britain) Anon, AE1, 5 (6), Nov-Dec 1965, 311-315.
27. Leak detectors and leak detection 27 : 22
Residual gas analysis by mass spectrometry. See abstract n u m b e r 560. 27 : 22 595. Muss-spectrometric leak detector of high sensitivity (MKh1102).
(USSR) A new type of mass-spectrometric leak detector (MKh1102) is described. Apart from its high sensitivity, this has a n u m b e r of other advantages over conventional types, including a linear characteristic and simple calibration, low background, and great stability with respect to time. The measuring system consists of four units: de amplifier, analyzer supply system, pressure gauge, and external control, each situated in its own chassis. The technological parameters of the new system are tabulated for comparison alongside those of the PTI-6 leak detector. Three references. V A Pavlenko et al, Pribory i Tekh Eksper, 5, 190. 27 : 56 596. Portable leak detector. (USA) Portable mass-spectrometer type helium leak detector will, according to manufacturer, detect one part helium in 10 million parts air. Assembly comprises gun-electrometer optics module in stainlesssteel housing, and portable solid-state electronics module that contains all controls and power supply. Anon, Mikros Div of Varian Associates, Capitol Highway, Portland,
Oregon. 27 597. Automatic leak tests. (USA) Leak test stations have a single, two-position switch that automatically controls the entire test cycle, making it simple for anyone to operate. A sensitivity of 5 x 10 -1= (Model MD-120A) and 1 x 10-11 std. cc/sec (Model MD-100A) is reported at full pumping speed. Testing cycle is started by moving the switch to "test" position; at termination, the switch is moved to "rest" position. The machine then automatically prepares itself for the next cycle. Anon, Vacuum Instruments Co, Stepar Place, Hungington, Station,
NY.
225