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VEB Labortechnik
Vacuum
news
mass ranges: M=I to 7; M=6 to 60 and M=25 to 250. Residual gas components of up to I per cent of the total gas load can be detected. Penning cold cathode gauges MGT 406 and MGT 706. are sensitive to discharae currents of up to 100 PA. With these instruments it is possible to take logarithmic pressure readings in the range lo-” to lO-B torr. The MGT 706 is a stageless extension of the MGT 406, working on another measurement principle, and is capable of pressures between 10 torr and IO-’ torr. In addition, other high vacuum equipment was shown, eg: valves, feedthroughs flange connections, thermal conductors and diaphragm vacuum gauges, halide leak deteclors,-rotary pumps with nominal pumping sneed of 350 m’/h and Roots _ Dumns _ of UD to 15,000 ma/h. A scale model of industrial impregnation eauipment comnleted the largest vacuum s&h at the Leipzig Spring Fair. In addition, Dreyer u Holland-Merten exhibited. in another hall. a nortable vacuum oil purification device Type 8.81 with a capacity of 500-800 litres/h, specially suitable for use in the purification of transformer oil. VEB Carl Zeiss, Jena exhibited a high vacuum evanorator HBA 12012. distinguished in’ particular by its ‘receiver (diameter x height 250 x 250). During the evaporation process all parts of the equipment could be observed through a wellimplosion-proof transparent designed bell-jar. The evaporator is specially suitable for the deposition of specimen holders used for successive investigations under an electron microscope. From the extensive general and technical programme of this firm, the two electron microscopes EF 4 (incorporating a 120 litre/sec oil diffusion pump) and the EF 5 should be mentioned. These are of wide application in research on crystallization and growth processes of evaporated films. VEB Laborteehnik, Ilmenau, exhibited a small rotarv numn and one- and two-stage gas ballast-pumps Type 1 DSl and Type 2 DSl with directlv connected motor (single block) and pumping speed of 1.2 m3/h. A well designed two-stage gas ballast pump Type 2 DS2 with V-belt drive, open or closed, was exhibited. Finally, a two-stage gas ballast pump Type VZ 3, with vertically constructed motors in both pump stages, was also shown.
Wiegand, Merseburg, exhibited a collective stand for chemical plant, several corrosionresistant ejector pumps and vacuum evaooratinn equipment. Not in the area of the technical fair, but in the Main Fair Hall. several glass diffusion pumps were on display. VEB JENAer Jena showed pump with a less than IO-’
Glaswerk
Schott II Gen of a two-stage oil diffusion speed of 12-14 litre/sec at torr.
Handwerkgenossenschaft Schmiedefeld, Rennsteig showed a three-stage mercury
diffusion pump RD 6 of novel design which was particularly distinguished by the fact that the boiler was externally heated. Pumping speed 6 litres/sec. Frithjof, Frauenwald i Thiir showed various
two and three-stage mercury diffusion pumps (Q 100, Q 150, Q 190) with pumping speeds of between 7 and 10 litreslsec at 1O-s torr.
Technical
and industrial
developments Roots pumps using Huhrich type rotors Two new series of Roots pumps have been announced by the French firm Alcatel develoned in collaboration with Polvsius GmbH (Germany). The novel feature of these pumps lies in the configuration of the rotors which in conventional types are of variable curvature. In the Hubrich design, which is employed in the AlcatelPolvsius numns. the blade nrofile is such that the &r&&e is at all-points mathematically circular. This means that throughout the entire cycle of the two rotors, each is geometrically tangential to the other and to the stator. The rotors are fabricated entirely by milling and high precision arindina. The advantages claimed for the new deiign include: reduction of tolerance values to a minimum by virtue of the high precision of the machining process; the gas channel for either suction or compression is much longer than that of conventional Roots pumps; the internal leakage is very low; practical throughputs are very close to the swept volume and high compression ratios can be accommodated without loss of performance; multiple pumping systems are more economic since the devices required for mechanical linkage are minimal; and since the fabrication process is not dependent on cutting tools, the production range of this type of Roots pump is virtually unlimited. The largest model in the present production range has a swept volume of 130.000 ms/hr. These pumps are not intended ‘for use as industrial booster pumps. All joints are flange-type and of “vacuum” quality and the diameter of the suction channels are designed for throughputs in the region of molecular flow. Also the internal gastightness between the lubricated gear case and the compression chamber has been carefullv studied to avoid oil contamination. In response to the variety of requirements encountered in vacuum technology, two different series of Alcatel-Polvsius pumps have been produced: the MIV series in which the motor operates under vacuum and the MAV series which are shaft-driven. The MIV series are designed for high vacuum operation and work best at low pressures with a low-powered motor. Due to the superior gas-tightness of these pumps, pressures in the 1O-6 torr range are easily attained by two MIV pumps with a
Alcatel-Polysius Roofs pump
two-stage forepump. The absence of rotation through ioints reduces maintenance to a minimum: The MAV series are nowered bv an exterior driving shaft and are not intended to operate at pressures below 10-a torr. Here the accent is on pump capacity and it is in this series that the 130,000 m’/hr model has been produced. Applications include metallurgical vacuum degassing, drying before impregnation of cables, fusion experiments and wind tunnels. Alcatel, France Circle number 45 on Reader Enquiry Service card
Leybold Vacuum Ltd have announced a new series of diffusion pumps, designated the Leyboditf series, which replace their existing DO pumps. The new series feature the following design modifications: (a) with the same main dimensions and the same inner diameter of the high vacuum flange, the pumping speed of the Leybodiffpumps is considerably higher than on the DO pumps; (b) the pump body and the connection flanges are made of stainless steel; (c) the new pumps are equipped with the new space-saving clamp flanges (LF), recently introduced in vacuum technology; (d) the cooling water is fed through a copper coil soldered to the pump body; (e) a thermal nrotection switch. which responds to overheating of the pump and switches off the heater, is fixed to the cooling coil; (f) a stirrer system, operated by the oil vapours, is fixed in the vertical axis of the jet assembly. It guarantees uniform evaporation of the oil and eliminates pressure oscillations or pressure bursts completely; (g) all pumps are available with a cold cap baffle; this reduces the oil backstreaming at the high vacuum connection to such an extent that only extremely sensitive methods can detect it at all. 409
news
mass ranges: M=I to 7; M=6 to 60 and M=25 to 250. Residual gas components of up to I per cent of the total gas load can be detected. Penning cold cathode gauges MGT 406 and MGT 706. are sensitive to discharae currents of up to 100 PA. With these instruments it is possible to take logarithmic pressure readings in the range lo-” to lO-B torr. The MGT 706 is a stageless extension of the MGT 406, working on another measurement principle, and is capable of pressures between 10 torr and IO-’ torr. In addition, other high vacuum equipment was shown, eg: valves, feedthroughs flange connections, thermal conductors and diaphragm vacuum gauges, halide leak deteclors,-rotary pumps with nominal pumping sneed of 350 m’/h and Roots _ Dumns _ of UD to 15,000 ma/h. A scale model of industrial impregnation eauipment comnleted the largest vacuum s&h at the Leipzig Spring Fair. In addition, Dreyer u Holland-Merten exhibited. in another hall. a nortable vacuum oil purification device Type 8.81 with a capacity of 500-800 litres/h, specially suitable for use in the purification of transformer oil. VEB Carl Zeiss, Jena exhibited a high vacuum evanorator HBA 12012. distinguished in’ particular by its ‘receiver (diameter x height 250 x 250). During the evaporation process all parts of the equipment could be observed through a wellimplosion-proof transparent designed bell-jar. The evaporator is specially suitable for the deposition of specimen holders used for successive investigations under an electron microscope. From the extensive general and technical programme of this firm, the two electron microscopes EF 4 (incorporating a 120 litre/sec oil diffusion pump) and the EF 5 should be mentioned. These are of wide application in research on crystallization and growth processes of evaporated films. VEB Laborteehnik, Ilmenau, exhibited a small rotarv numn and one- and two-stage gas ballast-pumps Type 1 DSl and Type 2 DSl with directlv connected motor (single block) and pumping speed of 1.2 m3/h. A well designed two-stage gas ballast pump Type 2 DS2 with V-belt drive, open or closed, was exhibited. Finally, a two-stage gas ballast pump Type VZ 3, with vertically constructed motors in both pump stages, was also shown.
Wiegand, Merseburg, exhibited a collective stand for chemical plant, several corrosionresistant ejector pumps and vacuum evaooratinn equipment. Not in the area of the technical fair, but in the Main Fair Hall. several glass diffusion pumps were on display. VEB JENAer Jena showed pump with a less than IO-’
Glaswerk
Schott II Gen of a two-stage oil diffusion speed of 12-14 litre/sec at torr.
Handwerkgenossenschaft Schmiedefeld, Rennsteig showed a three-stage mercury
diffusion pump RD 6 of novel design which was particularly distinguished by the fact that the boiler was externally heated. Pumping speed 6 litres/sec. Frithjof, Frauenwald i Thiir showed various
two and three-stage mercury diffusion pumps (Q 100, Q 150, Q 190) with pumping speeds of between 7 and 10 litreslsec at 1O-s torr.
Technical
and industrial
developments Roots pumps using Huhrich type rotors Two new series of Roots pumps have been announced by the French firm Alcatel develoned in collaboration with Polvsius GmbH (Germany). The novel feature of these pumps lies in the configuration of the rotors which in conventional types are of variable curvature. In the Hubrich design, which is employed in the AlcatelPolvsius numns. the blade nrofile is such that the &r&&e is at all-points mathematically circular. This means that throughout the entire cycle of the two rotors, each is geometrically tangential to the other and to the stator. The rotors are fabricated entirely by milling and high precision arindina. The advantages claimed for the new deiign include: reduction of tolerance values to a minimum by virtue of the high precision of the machining process; the gas channel for either suction or compression is much longer than that of conventional Roots pumps; the internal leakage is very low; practical throughputs are very close to the swept volume and high compression ratios can be accommodated without loss of performance; multiple pumping systems are more economic since the devices required for mechanical linkage are minimal; and since the fabrication process is not dependent on cutting tools, the production range of this type of Roots pump is virtually unlimited. The largest model in the present production range has a swept volume of 130.000 ms/hr. These pumps are not intended ‘for use as industrial booster pumps. All joints are flange-type and of “vacuum” quality and the diameter of the suction channels are designed for throughputs in the region of molecular flow. Also the internal gastightness between the lubricated gear case and the compression chamber has been carefullv studied to avoid oil contamination. In response to the variety of requirements encountered in vacuum technology, two different series of Alcatel-Polvsius pumps have been produced: the MIV series in which the motor operates under vacuum and the MAV series which are shaft-driven. The MIV series are designed for high vacuum operation and work best at low pressures with a low-powered motor. Due to the superior gas-tightness of these pumps, pressures in the 1O-6 torr range are easily attained by two MIV pumps with a
Alcatel-Polysius Roofs pump
two-stage forepump. The absence of rotation through ioints reduces maintenance to a minimum: The MAV series are nowered bv an exterior driving shaft and are not intended to operate at pressures below 10-a torr. Here the accent is on pump capacity and it is in this series that the 130,000 m’/hr model has been produced. Applications include metallurgical vacuum degassing, drying before impregnation of cables, fusion experiments and wind tunnels. Alcatel, France Circle number 45 on Reader Enquiry Service card
Leybold Vacuum Ltd have announced a new series of diffusion pumps, designated the Leyboditf series, which replace their existing DO pumps. The new series feature the following design modifications: (a) with the same main dimensions and the same inner diameter of the high vacuum flange, the pumping speed of the Leybodiffpumps is considerably higher than on the DO pumps; (b) the pump body and the connection flanges are made of stainless steel; (c) the new pumps are equipped with the new space-saving clamp flanges (LF), recently introduced in vacuum technology; (d) the cooling water is fed through a copper coil soldered to the pump body; (e) a thermal nrotection switch. which responds to overheating of the pump and switches off the heater, is fixed to the cooling coil; (f) a stirrer system, operated by the oil vapours, is fixed in the vertical axis of the jet assembly. It guarantees uniform evaporation of the oil and eliminates pressure oscillations or pressure bursts completely; (g) all pumps are available with a cold cap baffle; this reduces the oil backstreaming at the high vacuum connection to such an extent that only extremely sensitive methods can detect it at all. 409