57. New methods of producing and measuring vacuum in the electrical vacuum industry

57. New methods of producing and measuring vacuum in the electrical vacuum industry

Classified abstracts 47-59 20 : 25 47. Advances in vacuum and cryogenics. (USA) A review of recent trends, applications, and developments in the use o...

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Classified abstracts 47-59 20 : 25 47. Advances in vacuum and cryogenics. (USA) A review of recent trends, applications, and developments in the use of vacuum and cryogenic techniques, is presented. H A Steinherz and M H Hablanian, Ind Research, June 1966, 75-82.

20 48. Large dielectric vacuum facility. (USA) A large dielectric-walled vacuum vessel capable of low ultimate pressures and suitable for simulation of space operations is described. Constructional details of the 50 ft Plexiglass vacuum tank are presented. R G Jahn, Am lnst Aeronautics, 4, 1966, 1135. 20 49. Vacuum devices for the manufacture of semiconductors developed by Tesla Roznov, Czechoslovakia. (Czechoslovakia) The vacuum coater UP311/A is described in detail. This coater is used in " m e s a " technology and operates at a pressure of the order of 10-s torr. Brief mention is made of other available vacuum devices. J Mrazek, Jemn Mech Opt, 11 (6), Aug 1966, 236-237 (in Czech). 20 50. High vacuum systems for emission type electron microscopy.

(Czechoslovakia) A n experimental evacuating system used to verify the possibility of evacuating the immersion lens to 10-8 torr, without baking, is described. The system is fitted with a titanium getter pump, an orbitron type titanium p u m p and with a high frequency residual gas analyzer similar to the Farvitron type mass spectrometer. Typical mass spectra of the system are given. (Czechoslovakia) A Delong, Jemn Mech Opt, 11 (8), Aug 1966, 244-245 (in Czech). 20 51. Device for experiments at high temperature in vacuum or neutral gas conditions. (USSR) A chamber of internal dimensions 145 diameter by 420 m m which operates at 104 to 10-6 tort with temperature controlled up to 1200°C (resistance heating) is briefly described. V L Cherkasskiy et al, Zavodsk Lab, 32 (8), 1966, 1018-1019 (in

Russian). 20:37 52. Apparatus for studying the electron emission of worked metals.

(USSR) A new system for recording the electron emission of worked metals in vacuo is described. The vacuum is provided by a conventional backing-pump a n d diffusion-pump unit, and a specially-designed valve system enables the desired atmosphere to be admitted to the working chamber without cooling the diffusion pump. A working value of at least 2 × 10-5 torr is maintained throughout the experiments, which may last up to 30 hours. V S Kortov and R I Mints, Zavodsk Lab, 32 (9), 1966,1144 (in Russian). 20 53. New construction of a vacuum suction device. (USSR) The design of a new suction device with a simplified evacuation mechanism is described. This consists of a body with an attached elastic chamber communicating with the body through an opening closed with a valve; a spring rod in the valve moves vertically in the barrel. A n equation giving the vacuum for picking up objects with the suction device is presented. Picking up may be effected either with or without a signalling system; with such a system the whole operation of the device may be automated, objects being subjected to technological operations and counted at the same time. V M Leibovich and M Ya Shapil'skii, Mekh i Avtomat Proizv, No 1,

1966, 25 (in Russian). 20 54. A survey of vacuum evaporation devices manufactured by Laboratorni Pristroje, Prague, Czechoslovakia. (Czechoslovakia) After a short historical outline of vacuum coater manufacture at Laboratorni Pristroje (formerly Fysma), Prague, since 1942, a description of the current product range is given. The equipment described includes a small unit for the preparation of samples for electron microscopy: stainless steel bell jars of diameter 400 and 600 m m operating at pressures of the order of 10-5 torr. A similar bell jar using an oil diffusion p u m p with a liquid nitrogen baffle reaches a pressure of 10'e torr. All coaters are equipped with a combined thermocouple-Penning vacuum gauge, a resistance heated evaporator, a needle valve with controlled gas flow rate 10-e to 1 torr/litresee -1 a n d a device for optical checking of thin films. All these coaters are commercially available. (Czechoslovakia) 54

J Buril, Jemn Mech Opt, 11 (8), Aug 1966, 232-236 (in Czech). 20 55. Method of obtaining a high vacuum. (USSR) A new method of obtaining high vacuum in a comparatively short time without heavy power consumption is described. The volume to be evacuated is first filled with the vapour of a low-temperature liquid, which is then pumped out, the whole process being repeated a number of times. This facilitates the removal of adsorbed gases. The working substance may be water vapour or the vapours of alcohol, zinc, cadmium, etc.; the cooling agents may include liquid nitrogen, helium, carbon dioxide, etc. The method is especially valuable in connection with industrial vacuum lines. U I Ivanov, USSR Patent No 176,356, Appl 6th Dec 1962,publ'd lOth

Jan 1966.

21. Pumps and pump fluids 21 : 37 Cryostat for tensile-testing metals at the boiling point of liquid helium. See abstract number 211. 21:22 56. Mercury diffusion pump with vacuum gauge. (USSR) Difficulties encountered in the measurement of gas pressures in mercury-diffusion-pump systems are discussed; the high partial pressure of the mercury relative to the partial pressure of the residual gases distorts the readings of electrical vacuum gauges. These difficulties may be overcome by means of a new mercury diffusion pump incorporating a thermal vacuum gauge, in which the partial pressure of the gas being evacuated is measured continuously throughout the operation. The construction of the new p u m p is described in detail, together with the results of preliminary tests and instructions for adjusting the thermal vacuum gauge. F I Butaev and A A Pertsev, Elektrotekhnika, No 9,1966, 58 (in Russian). 21:22 57. New methods of producing and measuring vacuum in the electrical vacuum industry. (USSR) Recent advances in the use of electrical-discharge pumps for evacuating electronic apparatus are reviewed. The favourable characteristics of these pumps include the "purity" of the vacuum (absence of gases harmful to the apparatus), high limiting vacuum (10 -s torr), the absence of low temperature traps, simplicity in use and the absence of moving parts, long life and the absence of noise, instantaneous starting and stopping, and easy adaptability to automation. Another useful feature is the fact that the current through the p u m p is a direct measure of pressure; special supplementary vacuum gauges are therefore not required. Yu V Orlov, "Construction of Electronic Apparatus", publ'd by

"Energiya", Moscow, 1966, 127-136 (in Russian). 2l 58. Oil-free evacuation of electrical vacuum apparatus. (USSR) Centralized industrial vacuum equipment entirely free from oil pumps is described. Evacuation is effected entirely by means of sorption pumps. The principal components of the system are: carbon adsorption pumps, ion-sorption pumps, magnetic-discharge pumps, vacuum valves, pumping sockets, and measuring devices. The vacuum valves are made entirely of metal (stainless steel/copper etc.) and are demountable. The pumping speed depends on the type of adsorbent and is largely determined by the thermal conductivity of the adsorption layer. Activated carbon is particularly favourable. Carbon sorption pumps have a good pumping speed with respect to water vapour and carbon dioxide and are especially useful in the vacuum treatment of oxide cathodes. G A Vostrov et al, "Construction of Electronic Apparatus", publ'd by

"Energiya", Moscow, 1966, 119-126 (in Russian). 21 59. Fundamental constructional elements of vacuum technology in the production programme of Laboratorni Pristroje, Prague, Czechoslovakia. (Czechoslovakia) Contemporary mechanical rotary pumps RV 5/2 and RV 20/2, with speeds 5 m3hour-1 and 20 m3hour-x, respectively, and oil diffusion pumps series D O V (speeds from I0 litre/sec -a to 500 litre/sec -z) using silicon oil type Wacker A P 25. All described elements are commercially available. J Buril, Jemn Mech Opt, 11 (8), Aug 1966, 250-252 (in Czech).