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All-metal sealed vacuum connections
Classified
abstracts
1497-1509
by a synchroscope. The apparatus is manufactured Mikroskouov i Elektroavtomatiki, Sumv. USSR. V A Zelentsov, Pribory (in Russian).
Tekh Eksier,
li’(2),
by Zavodsk El
March-April
1967, 247 22
1497. Vacuum gauge.
(Germany) This operates on the radiometer principle, has an elongated perpendicular heated surface in a fixed position relative to the housing which supports a measuring element whose surface is parallel to and a short distance from the heated surface. The heating means are so arranged as to create a temperature gradient along the heated surface and the measuring element is suspended from a dynamometer which measures the pressure-dependent radiometer and/or lifting forces. (Author) Edwards High Vacuum Ltd, German Patent 1,240,300, Patent Abstr, 7 (24) part D, 21st June 1967, 3. 22 1498. Miniiture
ionisation
gauge.
(Great Britain) This gauge is capable of measuring pressures between 3 x 10-l and lo-lo torr and consists of a cylindrical envelope of 20 cm3 maximum volume, a closed base end and open opposite end. An accelerating grid anode electrode consists of a hollow cylindrical open fine wire grid 0.002 inches in diameter and 0.040 inch square spacing, positioned concentrically in the tube. A pair of thermionic emissive electrode filaments are external to and spaced apart from the grid. All connectors extend externally through the base and a thin wire probe ion collector is positioned concentrically in the space defined by the grid. General Electric Co. Erit Patent 1.067.468. 7 (21) oart D., , , Patent Abstr. _.,. 26th May 1967, 5. 22 1499. Ion current measuring apparatus. (Great Britain)
Suitable for ion gauges, mass spectrometers etc, to determine weak ionisation currents, the device includes an electrode which emits secondary electrons and a sensitive element for measuring the emitted electrons. A heater is arranged for continuous baking of the electrode during operation of the apparatus and a permanent magnet applies a field to the space between the electrode and electron-sensitive element. Leybold Holding A G, &it Patent 1,071,645, Patent Abstr, 7 (26) part D, 30th June 1967, 12.
23. PLUMBING 1500. New approaches to joints, vacuum systems. (France)
closure
and bake-out
23 : 28 in ultrahigh
Further experiments in the application of seals having “induced elasticity” are described. These seals consist of two concentric gaskets, of a metal having a high elastic limit, with the annuler space between them closely fitted by an aluminium ring of rectangular cross-section. Under deformation by flanges etc, a measure of elastic response is induced in the otherwise inelastic gasket seal, by the central aluminium ring. This principle has been applied to large diameter valves, bakeable to 400°C. A novel bakeout method for ultrahigh vacuum systems utilizes a plasma-sprayed alumina coating (about 0.1 mm thick) on the stainless steel walls with a further conductive film of nickel or titanium. Direct current heating of the conductive nickel film allows 400°C to be attained in a few minutes and bake-out may be completed in several cycles. Ultimate pressures in the ultrahigh vacuum range are unaffected by this treatment and, as well as lowering the power-consumption, the baking time may be reduced by half. R Bernard et al, Le We, 22 (128), March/Apd 1967,91-94 (in French). 23
plain-ended tubes and metal tubes is described. Wtth tube diameter variations of 0.5 mm these connections have a leakage of lO-1o lusec after 60 disconnections. S I Gendel et al, Pribory Tekh Eksper, 11 (2), March-April 1967, 223 (in Russian). 23 1503. Versatile sample holder for Bat samples at extremes of temperature in high vacuum. (USA)
A relatively simple, cheap and expedient way of containing such samples by means of reinforced stainless steel is described. The type of stainless steel is of no great consequence, so long as its surface is clean and all welds are of the inert arc type. E Y Weissman, Rev Sci Instrum, 38, 1967, 565. 23 1504. A simple mercury cut-off for use in gas admission to evacuated systems. (Great Britain) A modified mercury cut-off is described which allows the transference of gas from one limb to the other when there is a pressure difference between the limbs. D H T Spencer, J Sci Instrum, 44, 1967, 295. 23 1505. Device for providing a vacuum-tight passageway. (USA) Suitable for the introduction of a workpiece having an irregular shape, the device comprises a static seal consisting of a cylindrical casing with a coaxial rim forming an annular space and pressure chamber. A cylindrical elastic membrane surrounds the workpiece and is secured at its edges between the casing and the rim. A pressure difference is created thus providing a vacuum-tight application of the membrane against the workpiece or rim. A mechanism coaxial with the rim, locks the workpiece relative to the casing with a dynamic seal between the enclosure and casing and there is a means for rotating the casing. Comm 1’Energie Atomique, US Patent 2,323,788, Patent Office, 839 (l), 6th June 1967, 215.
Official
23 1502. All-metal se&d
vacuum connections.
(USSR) The design of indium wire sealed connections between glass or metal
US 23
1506. Dry seal for rotary shaft.
(USA)
This vacuum seal for a high speed rotary shaft, extends through a housing and has a part surrounding and contacting the shaft while static, A support for this part enables it to expand away from the shaft from the heat of friction upon rotation, before the heat becomes destructive. The spacing from the shaft during operation is sufficient to permit flow of a thin film of gas at atmospheric pressure into the housing between shaft and seal. The seal is formed entirely of a single piece of material. Technical Operations Inc, US Patent 3,325,172, Patent Ofice, 839 (2), 13th Juhe 1967, 645.
Official
Gaz
US
24. VALVES 24 1507. Three-way valves.
(USA)
Three body types were developed for 3-way valves, namely the double-ported bodies which had plugs outside the seat rings, singleported bodies which had a seat ring in the added port with plugs between the seat rings, and 3-way 3-position valves. C S Beard, Znstrum Control, 40, 1967, 115-l 19. 24 1508. All-glass syringe type valves for use in ultrahigh vacuum systems. (USA)
A new design of all-glass conductance valve embodying a syringe is described and illustrated diagrammatically. Particular advantages of this syringe vave are compactness and versatility. A M Cutteridge and P E Nel, Rev Sci Znstrum, 38, 1967, 554-555. 24
1501. Rubber-lead seal.
(USSR) A rubber ring of rectangular section is coated on three sides with a thin foil of lead or other metal. Vacuum sealing is effected by the metal foil so that the rubber is used only to exert pressure on the foil. In this manner, gases desorbed from the rubber are prevented from entering the vacuum system. The design of flanges for these seals is also described. V S Gumenyuk, Pribory Tekh Eksper, 11 (2), March-April 1967, 221-222 (in Russian).
Gaz
1509. Spiral liquid cooled ballle for shielding diffusion pumps.
(USA) The diffusion pump, which is connected to a cryogenically cooled chamber, has an inlet extending axially of the flow, while a cover is spaced and extends laterally of the flow. A first baffle, which can be cooled, is mounted on the housing and consists of a number of laterahy spaced baffle members disposed in overlapping optical tight relationship to optically insulate the interior of the chamber from the pump. A second baffle between this and the pump consists of a spiral cooling conduit mounted on a spiral member of successive coils overlapping to optically insulate. Warmer coolant is connected to the spiral. The cover is placed across the small end of the spiral, so 537
abstracts
1497-1509
by a synchroscope. The apparatus is manufactured Mikroskouov i Elektroavtomatiki, Sumv. USSR. V A Zelentsov, Pribory (in Russian).
Tekh Eksier,
li’(2),
by Zavodsk El
March-April
1967, 247 22
1497. Vacuum gauge.
(Germany) This operates on the radiometer principle, has an elongated perpendicular heated surface in a fixed position relative to the housing which supports a measuring element whose surface is parallel to and a short distance from the heated surface. The heating means are so arranged as to create a temperature gradient along the heated surface and the measuring element is suspended from a dynamometer which measures the pressure-dependent radiometer and/or lifting forces. (Author) Edwards High Vacuum Ltd, German Patent 1,240,300, Patent Abstr, 7 (24) part D, 21st June 1967, 3. 22 1498. Miniiture
ionisation
gauge.
(Great Britain) This gauge is capable of measuring pressures between 3 x 10-l and lo-lo torr and consists of a cylindrical envelope of 20 cm3 maximum volume, a closed base end and open opposite end. An accelerating grid anode electrode consists of a hollow cylindrical open fine wire grid 0.002 inches in diameter and 0.040 inch square spacing, positioned concentrically in the tube. A pair of thermionic emissive electrode filaments are external to and spaced apart from the grid. All connectors extend externally through the base and a thin wire probe ion collector is positioned concentrically in the space defined by the grid. General Electric Co. Erit Patent 1.067.468. 7 (21) oart D., , , Patent Abstr. _.,. 26th May 1967, 5. 22 1499. Ion current measuring apparatus. (Great Britain)
Suitable for ion gauges, mass spectrometers etc, to determine weak ionisation currents, the device includes an electrode which emits secondary electrons and a sensitive element for measuring the emitted electrons. A heater is arranged for continuous baking of the electrode during operation of the apparatus and a permanent magnet applies a field to the space between the electrode and electron-sensitive element. Leybold Holding A G, &it Patent 1,071,645, Patent Abstr, 7 (26) part D, 30th June 1967, 12.
23. PLUMBING 1500. New approaches to joints, vacuum systems. (France)
closure
and bake-out
23 : 28 in ultrahigh
Further experiments in the application of seals having “induced elasticity” are described. These seals consist of two concentric gaskets, of a metal having a high elastic limit, with the annuler space between them closely fitted by an aluminium ring of rectangular cross-section. Under deformation by flanges etc, a measure of elastic response is induced in the otherwise inelastic gasket seal, by the central aluminium ring. This principle has been applied to large diameter valves, bakeable to 400°C. A novel bakeout method for ultrahigh vacuum systems utilizes a plasma-sprayed alumina coating (about 0.1 mm thick) on the stainless steel walls with a further conductive film of nickel or titanium. Direct current heating of the conductive nickel film allows 400°C to be attained in a few minutes and bake-out may be completed in several cycles. Ultimate pressures in the ultrahigh vacuum range are unaffected by this treatment and, as well as lowering the power-consumption, the baking time may be reduced by half. R Bernard et al, Le We, 22 (128), March/Apd 1967,91-94 (in French). 23
plain-ended tubes and metal tubes is described. Wtth tube diameter variations of 0.5 mm these connections have a leakage of lO-1o lusec after 60 disconnections. S I Gendel et al, Pribory Tekh Eksper, 11 (2), March-April 1967, 223 (in Russian). 23 1503. Versatile sample holder for Bat samples at extremes of temperature in high vacuum. (USA)
A relatively simple, cheap and expedient way of containing such samples by means of reinforced stainless steel is described. The type of stainless steel is of no great consequence, so long as its surface is clean and all welds are of the inert arc type. E Y Weissman, Rev Sci Instrum, 38, 1967, 565. 23 1504. A simple mercury cut-off for use in gas admission to evacuated systems. (Great Britain) A modified mercury cut-off is described which allows the transference of gas from one limb to the other when there is a pressure difference between the limbs. D H T Spencer, J Sci Instrum, 44, 1967, 295. 23 1505. Device for providing a vacuum-tight passageway. (USA) Suitable for the introduction of a workpiece having an irregular shape, the device comprises a static seal consisting of a cylindrical casing with a coaxial rim forming an annular space and pressure chamber. A cylindrical elastic membrane surrounds the workpiece and is secured at its edges between the casing and the rim. A pressure difference is created thus providing a vacuum-tight application of the membrane against the workpiece or rim. A mechanism coaxial with the rim, locks the workpiece relative to the casing with a dynamic seal between the enclosure and casing and there is a means for rotating the casing. Comm 1’Energie Atomique, US Patent 2,323,788, Patent Office, 839 (l), 6th June 1967, 215.
Official
23 1502. All-metal se&d
vacuum connections.
(USSR) The design of indium wire sealed connections between glass or metal
US 23
1506. Dry seal for rotary shaft.
(USA)
This vacuum seal for a high speed rotary shaft, extends through a housing and has a part surrounding and contacting the shaft while static, A support for this part enables it to expand away from the shaft from the heat of friction upon rotation, before the heat becomes destructive. The spacing from the shaft during operation is sufficient to permit flow of a thin film of gas at atmospheric pressure into the housing between shaft and seal. The seal is formed entirely of a single piece of material. Technical Operations Inc, US Patent 3,325,172, Patent Ofice, 839 (2), 13th Juhe 1967, 645.
Official
Gaz
US
24. VALVES 24 1507. Three-way valves.
(USA)
Three body types were developed for 3-way valves, namely the double-ported bodies which had plugs outside the seat rings, singleported bodies which had a seat ring in the added port with plugs between the seat rings, and 3-way 3-position valves. C S Beard, Znstrum Control, 40, 1967, 115-l 19. 24 1508. All-glass syringe type valves for use in ultrahigh vacuum systems. (USA)
A new design of all-glass conductance valve embodying a syringe is described and illustrated diagrammatically. Particular advantages of this syringe vave are compactness and versatility. A M Cutteridge and P E Nel, Rev Sci Znstrum, 38, 1967, 554-555. 24
1501. Rubber-lead seal.
(USSR) A rubber ring of rectangular section is coated on three sides with a thin foil of lead or other metal. Vacuum sealing is effected by the metal foil so that the rubber is used only to exert pressure on the foil. In this manner, gases desorbed from the rubber are prevented from entering the vacuum system. The design of flanges for these seals is also described. V S Gumenyuk, Pribory Tekh Eksper, 11 (2), March-April 1967, 221-222 (in Russian).
Gaz
1509. Spiral liquid cooled ballle for shielding diffusion pumps.
(USA) The diffusion pump, which is connected to a cryogenically cooled chamber, has an inlet extending axially of the flow, while a cover is spaced and extends laterally of the flow. A first baffle, which can be cooled, is mounted on the housing and consists of a number of laterahy spaced baffle members disposed in overlapping optical tight relationship to optically insulate the interior of the chamber from the pump. A second baffle between this and the pump consists of a spiral cooling conduit mounted on a spiral member of successive coils overlapping to optically insulate. Warmer coolant is connected to the spiral. The cover is placed across the small end of the spiral, so 537