- Email: [email protected]
1694. Furnaces for vacuum heat treatment
Classified abstracts 1694--1710 The results of the determination of the pumping speed employing conventional methods deviate from the product ACef based on concepts of the kinetic theory of gases, where A C e ~ A Vav/4 is the conductance of an orifice, if the capture probability f is not small. This deviation may be attributed to the technique of pressure measurement. In order to obtain proportionality between capture probability and speed with a unique constant of proportionality in the whole range 0~f--~ 1 it is recommended that the pumping speed be defined using the pressure of a large vessel at a place where the isotropic state is maintained to a high degree. This speed is named intrinsic speed and it may be measured using Knudsen's large chamber fitted with a proper gas inlet system. The considerations presented in this paper are intended as a contribution to an international standardization of the speed measurement of high vacuum pumps. R Buhl, J Vac Sci Technol, 3 (3), 1966, 83-91. 2l 1694. Furnaces for vacuum heat treatment. (USA) Review of applications and types of furnaces, including vacuum annealing of refractory materials, Cu, and stainless steels, hardening of high speed and die steels, vacuum brazing techniques and sintering of WC. F J Becket, A TB Met, 5 (5), 1965, 159-164. 21 1695. Tubular oven for a 250°C short-cycle vacuum heat treatment.
(USA) To increase the heat transfer, which in a vacuum must occur by radiation, articles under treatment are placed in double-walled cylinders of small diameter in proportion to their length. L Maurice, ATB Met, 5 (5), 1965, 165-169 (in French). 21 1696. On the use of a diffusion pump oil in mechanical pumps. (USA) Use of Dow Coming DC 704 or 705 oil in the mechanical fore-pump was shown to reduce considerably the backstreaming problem from the oil normally used in mechanical pumps. T W Haas and A G Jackson, J Vac Sci Technol, 3 (3), 1966, 168-169. 21 1697. Titanium filaments for sublimation pumps. (USA) The performance of an alloy of 85 per cent Ti and 15 per cent Mo as a filament material for subliming Ti in getter pumps is described. Using 2.1 mm diameter filaments, evaporation rates of up to I rag/ cm/min have been achieved at filament currents of 57 A. The upper limit in the evaporation rate is caused by filament failure which is attributed to crystal growth but at values below this limit the evaporation is extremely uniform and reproducible. G M McCracken and N A Pashley, J Vac Sci Technol, 3 (3), 1966,
96-98. 21 1698. Cryosorption pumping of hydrogen at 20°K. II. Development and performance of cryosorption panels. (USA) The development of eryosorption panels consisting of molecular sieve adsorbents bonded to refrigerated aluminiurn plates is described, The pumping of hydrogen by cryosorption panels at temperatures near 20°K has been shown to be efficient and practical. This technique can be scaled up without difficulty for use in large vacuum chambers. S A Stern et ai, J Vac Sci Technol, 3 (3), 1966, 99-106. 21 1699. Liquid-ring vacuum pumps and boiling control. (USA) In removing noncondensables from sugar solutions a vacuum pump with a seal of water may be utilized, because of its ability to condense vapours during compression. The liquid seal is in dynamic and intimate contact with the in coming air-vapour mixture. Anon, Sugar Azucar, 60 (12), 1965, 34-37. 21 : 30 1700. Selecting vacuum equipment for the thin-film processing line. II. Diffusion ion pumped systems. (USA) Comprehensive survey of vacuum equipment describing and comparing diffusion and ion pumped evaporation systems. Various vacuum measuring devices are considered including ionization gauges. A L Hobson, Electronic Packaging and Production, 6, 1966, 34-39. 21 1701. Adsorption pumps. (Italy) The operating principles of the adsorption pump are outlined and some data obtained in the application of the adsorption pump are presented. V Chimenti, Laboratorio Nazionale di Frascati, Italy, 1966, 16 pages.
21 1702. Backstreaming from oil diffusion pumps. (USA) A program was conducted to evaluate the backstreaming characteristics of oil diffusion pumps in well baffled systems, and turbomolecular pumps. W N Langdon, IH Res lnst, Chicago, 1966, 17 pa.~es. 21 1703. Extreme vacuum technology including cryosorption, diffusion pumps and pressure calibration studies. (USA) The research tasks of this program relate to the development and application of extreme vacuum science and technology. The tasks range from the production and calibration of extreme vacuum to a study of the eryosorption process. P J Bryant and G M Gosselin, Midwest Research Inst, Kansas City,
1966, 56 pages. 21 1704. Vapour-jet vacuum pumps in process technology. (Germany) Of all types of jet pumps, the vapour jet vacuum pumps are considered as becoming increasingly important. The construction and the operation of such pumps is cxplained in detail on characteristic efficiency, pressure drop, and velocity curves. The performances of vapour-jet vacuum pumps in process technology are discussed and 5 types of pump are described in detail A Hnpe, Chem Ing'r Tech, 38 (3), 1966, 247-249 (in German): 21 1705. Low density boundary layer control by liquid hydrogen cryopumping. (USA) W N Maedermatt et al, ARO Inc, Arnoht Air Force Station, Term,
1966. 21 1706. Orhitron--a new principle in ion pumping. (USA) Orbitron is an electrostatic device in which electrons are emitted from a filament with sufficient angular momentum so that they orbit around a central electrode which is at a positive potential and which is mounted concentrically inside another hollow cylinder that is grounded. Based on the principle of the orbitron, the ion vacuum pump is a completely electrostatic pump. Maintaining constant speed in the ultrahigh vacuum range, the elimination of a magnet enables design of smaller and lighter ion pumps. J S Maliakal and R G Herh, Research/Development, June 1966, 17~
54-57. 21 1707. The pumping theory of diffusion pumps. (Hungary) The study of the pumping effect is approached with aid of the kinetic theory of nonuniform gases. An equation is derived and solved for an ideal gas. The model seems to favour pump-types with high compression ratio stages. The complete solution of the problem is to determine the optimum jet for a given pressure range, the cross sections of nozzle and pump chamber and the necessary boiler input. G Toth, Acta Phys Acad Sci Hung, 20, 1966, 99-114 (in English). 21 1708. Graphical method for the determination of the pumping speed of Roots pumps as a function of backing pump. (Germany) The graphic method is based on the calculations of W Armbuster and A Lorenz. The characteristics of forepumps and Roots pumps are plotted on a right-angled system of coordinates with log-log division. The two families or curves referring to the Roots pumps run roughly diagonally on the table, one curve each of the two families belonging to one Roots pump. Determination of the pumping speed or pump combinations is explained by consecutive drawing of five straight lines. A Kirehner, Vakuum-Technik, 15, 1966, 144-147 (in German). 21 : 22 : 25 1709. New Zeiss Jena products in the Spring Leipzig Fair 1966.
(Czechoslovakia) This paper contains a description of some optical apparatus and following vacuum devices: cold trap type DSO 32, high vacuum unit HVAO-6/30/ll, containing oil diffusion pump with the speed of 30 1/see-j, measuring unit type HVMK-6, containing 2 thermistor gauge and one Penning gauge bakeable at 400°C. Photographs are included. (G.D.R.) R Jobst, Jemna Mech Opt, 11, (3), Mar 1966, 95-98 (in Czech). 21 1710. Getter-ion pumps with direct heated titanium evaporator. (USSR)
509
(USA) To increase the heat transfer, which in a vacuum must occur by radiation, articles under treatment are placed in double-walled cylinders of small diameter in proportion to their length. L Maurice, ATB Met, 5 (5), 1965, 165-169 (in French). 21 1696. On the use of a diffusion pump oil in mechanical pumps. (USA) Use of Dow Coming DC 704 or 705 oil in the mechanical fore-pump was shown to reduce considerably the backstreaming problem from the oil normally used in mechanical pumps. T W Haas and A G Jackson, J Vac Sci Technol, 3 (3), 1966, 168-169. 21 1697. Titanium filaments for sublimation pumps. (USA) The performance of an alloy of 85 per cent Ti and 15 per cent Mo as a filament material for subliming Ti in getter pumps is described. Using 2.1 mm diameter filaments, evaporation rates of up to I rag/ cm/min have been achieved at filament currents of 57 A. The upper limit in the evaporation rate is caused by filament failure which is attributed to crystal growth but at values below this limit the evaporation is extremely uniform and reproducible. G M McCracken and N A Pashley, J Vac Sci Technol, 3 (3), 1966,
96-98. 21 1698. Cryosorption pumping of hydrogen at 20°K. II. Development and performance of cryosorption panels. (USA) The development of eryosorption panels consisting of molecular sieve adsorbents bonded to refrigerated aluminiurn plates is described, The pumping of hydrogen by cryosorption panels at temperatures near 20°K has been shown to be efficient and practical. This technique can be scaled up without difficulty for use in large vacuum chambers. S A Stern et ai, J Vac Sci Technol, 3 (3), 1966, 99-106. 21 1699. Liquid-ring vacuum pumps and boiling control. (USA) In removing noncondensables from sugar solutions a vacuum pump with a seal of water may be utilized, because of its ability to condense vapours during compression. The liquid seal is in dynamic and intimate contact with the in coming air-vapour mixture. Anon, Sugar Azucar, 60 (12), 1965, 34-37. 21 : 30 1700. Selecting vacuum equipment for the thin-film processing line. II. Diffusion ion pumped systems. (USA) Comprehensive survey of vacuum equipment describing and comparing diffusion and ion pumped evaporation systems. Various vacuum measuring devices are considered including ionization gauges. A L Hobson, Electronic Packaging and Production, 6, 1966, 34-39. 21 1701. Adsorption pumps. (Italy) The operating principles of the adsorption pump are outlined and some data obtained in the application of the adsorption pump are presented. V Chimenti, Laboratorio Nazionale di Frascati, Italy, 1966, 16 pages.
21 1702. Backstreaming from oil diffusion pumps. (USA) A program was conducted to evaluate the backstreaming characteristics of oil diffusion pumps in well baffled systems, and turbomolecular pumps. W N Langdon, IH Res lnst, Chicago, 1966, 17 pa.~es. 21 1703. Extreme vacuum technology including cryosorption, diffusion pumps and pressure calibration studies. (USA) The research tasks of this program relate to the development and application of extreme vacuum science and technology. The tasks range from the production and calibration of extreme vacuum to a study of the eryosorption process. P J Bryant and G M Gosselin, Midwest Research Inst, Kansas City,
1966, 56 pages. 21 1704. Vapour-jet vacuum pumps in process technology. (Germany) Of all types of jet pumps, the vapour jet vacuum pumps are considered as becoming increasingly important. The construction and the operation of such pumps is cxplained in detail on characteristic efficiency, pressure drop, and velocity curves. The performances of vapour-jet vacuum pumps in process technology are discussed and 5 types of pump are described in detail A Hnpe, Chem Ing'r Tech, 38 (3), 1966, 247-249 (in German): 21 1705. Low density boundary layer control by liquid hydrogen cryopumping. (USA) W N Maedermatt et al, ARO Inc, Arnoht Air Force Station, Term,
1966. 21 1706. Orhitron--a new principle in ion pumping. (USA) Orbitron is an electrostatic device in which electrons are emitted from a filament with sufficient angular momentum so that they orbit around a central electrode which is at a positive potential and which is mounted concentrically inside another hollow cylinder that is grounded. Based on the principle of the orbitron, the ion vacuum pump is a completely electrostatic pump. Maintaining constant speed in the ultrahigh vacuum range, the elimination of a magnet enables design of smaller and lighter ion pumps. J S Maliakal and R G Herh, Research/Development, June 1966, 17~
54-57. 21 1707. The pumping theory of diffusion pumps. (Hungary) The study of the pumping effect is approached with aid of the kinetic theory of nonuniform gases. An equation is derived and solved for an ideal gas. The model seems to favour pump-types with high compression ratio stages. The complete solution of the problem is to determine the optimum jet for a given pressure range, the cross sections of nozzle and pump chamber and the necessary boiler input. G Toth, Acta Phys Acad Sci Hung, 20, 1966, 99-114 (in English). 21 1708. Graphical method for the determination of the pumping speed of Roots pumps as a function of backing pump. (Germany) The graphic method is based on the calculations of W Armbuster and A Lorenz. The characteristics of forepumps and Roots pumps are plotted on a right-angled system of coordinates with log-log division. The two families or curves referring to the Roots pumps run roughly diagonally on the table, one curve each of the two families belonging to one Roots pump. Determination of the pumping speed or pump combinations is explained by consecutive drawing of five straight lines. A Kirehner, Vakuum-Technik, 15, 1966, 144-147 (in German). 21 : 22 : 25 1709. New Zeiss Jena products in the Spring Leipzig Fair 1966.
(Czechoslovakia) This paper contains a description of some optical apparatus and following vacuum devices: cold trap type DSO 32, high vacuum unit HVAO-6/30/ll, containing oil diffusion pump with the speed of 30 1/see-j, measuring unit type HVMK-6, containing 2 thermistor gauge and one Penning gauge bakeable at 400°C. Photographs are included. (G.D.R.) R Jobst, Jemna Mech Opt, 11, (3), Mar 1966, 95-98 (in Czech). 21 1710. Getter-ion pumps with direct heated titanium evaporator. (USSR)
509