Vacuum News

It provides a primary calibration standard covering a gas flow range

from 0.1 to 2000 cm3 min’ and operates by a volume displacement

method giving an accuracy of 0.25% traceable to NBS. It is priced at

less than f900. only a tenth of the cost of other pnmary standard

volumetric displacement flow calibrators.

Chell Instruments Ltd.

Tudor House, Grammar School Road, North Walsham,

Norfolk NR28 9JH

Tel 0692 402488

Telex 97198 Chell G

New Maglev turbomolecular pumps offer high performance

A new series of turbomolecular pumps features magnetic levrtatron of

the rotor, which therefore does not run in frictional contact with

bearings. This means that no lubricant is needed for the rotary

mechamsm, so the high vacuum produced by the pumps IS

completely free from hydrocarbon contaminants.

A second important advantage of this technrque in the pumps, lust

introduced by Edwards High Vacuum, is that it results in an extremely

low level of noise and vibration. Peak-to-peak vibration level IS less

than 0.05 pm.

Compnstng a pump unrt and a control unrt, the new turbomolecular

desrgn is available in three models, with pumping speeds of 270, 340

and 2000 I s-’ (for nitrogen). The two smaller models are particularly

versatile for fitting tnto systems because they can be mounted in any

orientation

Edwards Hugh Vacuum,

Manor Royal, Crawley, West Sussex RHlO 2LW

Tel 0293 28844

Telex 87123 Edivac G

New two-stage rotary vacuum pump

Edwards High Vacuum has added yet another pump size to its

popular and proven EM range of direct-drive rotary vacuum pumps.

The E2M28 is a two-stage model with a displacement of

32.2 m3 h ’ It offers a useful pumping capacity between Edwards

existing E2M18 and E2M40 models.

Featuring roller bearings in a rugged, rndustrial construction, the

E2M28 is made in high quality corrosion-resistant materials and

combines its high capacity with compact dimensions. It is capable of

producing an ultimate vacuum of 1 x 10 4 mbar.

A new addition to Edwards EM range of direct-drive rotary vacuum

pumps. The E2M28 is a two-stage model with a displacement of

32.2 m3 h- I. A complete range of easy-to-fit accessories to protect

both the pump and environment are available.

Like all other EM series rotary pumps, the E2M28 Incorporates an

advanced, positive-pressure lubricatron system usrng an integral

high-capacity oil pump. This ensures reliable running even at high

gas loads. The Edwards lubrication system has proved partrcularly

successful in enabling these high vacuum pumps to cope with

today’s rugged industrial applications, for example semrconductor

processing.

Available for the E2M28 IS a complete range of easy-to-frt

accessories to protect both pump and environment and the pump

itself is built to exacting safety standards. Users can fit the pump

confidently, In the knowledge that it IS backed-up by Edwards’

International service network

Edwards High Vacuum,

Manor Royal, Crawley, West Sussex RHlO 2LW

Computer-controlled test equipment for vacuum switches

Vacuum swatches. or Interrupters, are used In rndustrral power control

for swrtching high voltage, high current electrical circuits, typically rn

the region of 3300 V at 400 A ac. To achieve the required electrical

performance and prevent oxidation of the contacts during opening

and closing, the body of each switch forms a vacuum chamber which

IS sealed for the life of the switch.

W A Technology of Cambridge has designed automatrc,

microprocessor-controlled test equipment for a major manufacturer of

these switches with a development programme partially funded by a

grant from the Department of Trade & Industry’s Microelectronics

Applicatron project. The machrne carries out an essential magnetron

test to measure vacuum pressure by applyrng a crossed electnc and

magnetic field measurement of the current passed indicates the

vacuum

WA Technology,

Temporary address

Umt 134, Cambridge Science Park, Milton Road,

Cambridge CB4 4GD

Tel 0223 862212

The new prethinning instrument for TEM specimen preparation

We are pleased to announce the arrival of the VCR DrmplerTM Into

the European market. This instrument has proven to be extremely

successful in Northern America, as well over 50 machrnes are in

The new prethinning instrument for TEM specimen preparation.

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