Vacuum
LMD925
News
miniature
linear
motion
drive
vacuum of IO -4 torr. Their and 20.5 m3/h respectively.
Vacuum Generators Ltd have recently announced an addition to their range of miniature Ultra High Vacuum components. The LMD925 is a linear motion drive mounted on a 1.33 in. mini FC flange, giving a total movement of 25 mm. Suitable for use down to the 10 -‘I torr range, this device is bakable to 350°C, and will
displacements
are 7 m3/h,
14.6
m3/h
Cooling running, which is achieved by use of an integral fan-cooled heat exchanger (a unique feature of EDM pumps) produces significant advantages : it contributes to the cleanliness of the vacuum system bv reducing back-streaming and it also, by increasing oil viscosity, contributes to quiet operation and improved reliability. An advanced lubrication system is fitted to EDM pumps which ensures the best possible ultimate vacuum under all conditions and also improves the ability of the pumps to deal with vapour. This is achieved by metering only clean, degassed oil to the high vacuum stage, and by automatically increasing oil flow to the low vacuum stage when required under gas ballasting conditions. Ultimate vacuum under full gas ballast is 10 -z torr for all pumps. An automatic valve oil-suck-back when of a power failure.
isolates the vacuum system EDM pumps are switched
and prevents off or in the event
All three pumps are constructed to metric measurements. They are available as 220 V single phase 50 Hz, or 380-440 V 3 phase 50 Hz models, but motors can easily be changed if alternative voltages are required. Edwards High Vacuum Circle number 43 on Reader Enquiry Service card
Two new Edwards
high-frequency
spark
testers
from
Edwards High Vacuum (part of BOC Ltd) have introduced two new high-frequency spark testers, the type ST4M, which has an output frequency of 3.8 mHz and output voltage variable up to 30 kV, and the ST2OOK, with output frequency of 200 kHz and output voltage variable up to 50 kV. Both are designed for maximum operator safety, with advanced insulation and safety devices. They are both suitable for leak location on glass vacuum systems, insulation testing, leakage path removal, ozone production, excitation of gas discharge lamps, and providing high frequency power supplies for laboratory use.
Miniature
linear
motion
The STM4 takes the form of a light (3 kg) generator suitable for portable or bench-mounted operation with a hand-held test unit weighing about $ kg. All controls, including earth return socket for the test unit lead, are mounted on the front of the generator case to simplify operation.
drive
find many applications where space is restricteti. of the drive in its extended position is 180 mm, thimble is calibrated for accurate positioning. A motorized version confined or hazardous
is also available, environments.
Circle
New direct-drive efficient
allowing
The overall length and the drive remote
number
42 on Reader
vacuum
pumps
operation
Vacuum Generators Enquiry Service
are quiet
in Ltd card
and
Three new direct-drive vacuum pumps from Edwards High Vacuum (part of BOC Ltd) are claimed to be quieter and cooler in operation than any other equivalent pumps available. They are claimed also to be exceptionally efficient and remarkably free from vibration. The pumps, which are of the 2-stage type, EDM6, EDM12 and EDM20. They all have 76
are designated an ultimate obtainable
The ST2OOK is a completely self-contained hand-held pistol unit weighing less than 14 kg, with a tough polypropylene case built to withstand rough treatment in an industrial environment. Very suitable for use in areas with restricted access, it has a 150 mm screw-in probe-other shapes and sizes of probe can be fitted if required. All controls are mounted in the handle : double-pole on-off switch, voltage selection plug and voltage control. Edwards High Vacuum Circle number 44 on Reader Enquiry Service card
New
pirani
gauge
A new range of low cost vacuum gauges by The General Engineering Co (Radcliffe)
is now Ltd.
being
introduced
The PlR.2 Pirani gauge is a compact, robust, portable unit which is also suitable for panel mounting. Used in conjunction with the PGH.4 gauge head, which will shortly be available with a Kleinflange termination, pressures in the 1 torr to 10 -3 torr range can be measured. To improve readability two scales are used and the gauge accommodates two heads.