Price reduction of a mass spectrometer

Vacuum News allow, may be combined w~th the facility of separation, to design a hghtweight assembly with a h~gh packing density, for example a stack of power diodes. Thermal balancing heatsmks have a variety of apphcatlons, not the least of which is batch testing a number of solid state devices all at the same temperature. Conventionally, large masses of metal provide the thermally conductive path, heat p~pes give a superior performance In th~s field, m order to maintain a near isothermal surface, design values of the radml flux are kept as low as possible consistent with the geometry of the dewce mounting 0 1 to 1/W cm 2 Js typical w~th temperature vanat~ons of 0 1 to 1 °C respectively An example which embodies remote cooling, hghtwelght heatsmkmg and near ~sothermal operation, ~s the application to card frame units In th~s apphcatmn, the heat from all the DIL packages on the pc board is transferred to the handle, which doubles as a heat sink In the field of microwave components there are many instances where large amounts of heat can be generated in a confined space. Examples include circulators, isolators, rotating joints and dummy loads, as well as such active devices as klystrons, magnetrons, crossed field amplifiers and travelhng wave tubes The current use of heat pipes m this field is mimmal, but the potential is considerable. S u m m a r y . The design parameters of heat pipes may generally be expressed as performance hmlts such as those given in Table 1, rather than as a performance characteristic. The overall thermal performance of a system is usually determined by the heat sink when the heat pipe is operating within those hmlts. Although apphcatlons in electronics are presently potentml rather than current, interest =s at a h=gh and increasing level Current market demands, in large part can be met by water filled, tubular heat p~pes w~th a s~mple woven wire mesh structure. Redpomt Assoc=ates Ltd Circle number 40 on Reader Enquiry Service card

Price reduction of a mass spectrometer Vanan have been able to reduce the price of their CH7 Mass Spectrometer by offering it in a standard configuration, and taking advantage of economies ~n scale of product=on New accessories such as field desorptlon source, chemical ionization source, multmple ion selection and high capacity pumping system are also available. Vanan Associates Ltd Circle number 41 on Reader Enquiry Service card

Vacuum valve system The combined pump-out and safety valve (V15-03-NW) and the magentic service coupling for this valve (V15-01 -NW) have been developed for applications where a number of permanently evacuated h=gh vacuum insulated pieces of equipment are m use (dewar vessels, cryostats, transfer tubes). Vacuum pumping and re-evacuation are carried out by use of a common vacuum service coupling, w~th maximum economy in installation costs and space requmrements.

The construct=on of the pump-out and safety valve prevents inadvertent opening On equipment where accidental pressurization of the vacuum space can occur, a spring-loaded and vented cover ~s fitted to the pump out valve, thus converting ~t to a safety valve In case of accidental pressure rise (above atmospheric) 262

Vacuum valve system V- 15 from R/cot L t d

the plug is automatically hfted off the seat, freeing a vent path through the holes prowded in the cover. The advantages claimed by the manufacturers are tamper-proof system--valve can be opened to atmosphere for re-evacuation or venting only by means of the magnet=c service couphng, economy--one operator for several pump-out ports, adaptabdity-one operator can be used, w~th suitable adapters, to operate smaller pump-out ports of various sizes (i e large d~ameter valve on cryostat and small diameter, valves on transfer lines can be pumped w~th one valve operator), convemence of operation-positive engagement by magnet replaces blind groping for internal threads or bayonet ioints, =mproved performance--seahng of convent=onal valve operators ~s by O-rings on a p~ston shdmg m valve body ('Wdson seal'). Ricor 'packless" construction using a bellows movement demonstrably reduces pressure r=se =n vacuum insulatmn by a factor of approx 25 at pressures m the 1 x 10-5 torr range, as compared to conventmnal valves Ricor Ltd Circle number 42 on Reader Enquiry Serwce card P l a t e seals The seals are of the rubber-to-metal bonded type, having a sealing face on each side of the metal retaining plate

The material specification for both the retaining plate and the rubber seal can be vaned to suit the particular environment m which they are finally sited The seals, can be used for htgh or low pressure apphcatlons. The bonded plate saves the costly operat=on of machimng grooves m the mating faces of the flanges, and the difficult task of fitting extruded or moulded seals. The plates are also very easy to replace, and =t =s merely necessary to remove the fastening bolts--shde out the old plate--and insert the new one Palmer Rubber Products Division Circle number 43 on Reader Enquiry Serwce card

E x h i b i t i o n success Torvac, of Histon (Cambridge) and Skelmersdale in Lancashire, were the only company to sell their exhibit, a CVE 31 B electron beam welder valued at about £10,000, at the recent Exh=bttion of Advanced Welding Techniques at the British Marketing Centre in Tokyo Torvac Ltd Circle number 44 on Reader Enquiry Serwce card