New seal user's design kit

Vacuum

News Apart from the speed of operation, Alfa-Lava1 claim that their system is more reliable, durable and accessible than alternatives, since the units can be mounted on a base plate on the side of the vehicle chassis. The vacuum pump is able to cope independently with the problems which can occur in tanker applications, for example flooding with milk if the tanker is overfilled. Alfa-Lava1 Co. Ltd Circle number 37 on Reader Enquiry Service card

Photomultiplier supply from 35 V dc input

provides

up to 1.5 kV

A new high-voltage power supply from Brandenburg Ltd, the Model 455A. is designed for use with photomultipliers, and can provide a positive output up to 1.5 kV from an input voltage of of 35 V dc. The module incorporates a reference voltage source which is compared with a sample of the output voltage to derive a controlled dc supply to a high-frequency inverter. The high-voltage secondary output is fed into a rectifier section and finally through a highly efficient filter. The tolerance on the +35V input ripple content of 5% peak-to-peak. exceed 600 mA under maximum New

bakeable

electromagnetic being coated.

Pirani

vacuum-gauge

beam deflection

head

protects

the cathode

from

DC heating ensures minimum spot size and intensive cooling prevents crucible reactions and any secondary evaporation. Beam power of the EHVI 08 power unit is 7 kW and the EHVl 1 OA 15 kW. Simultaneous operation of up to three evaporation sources in one or more vacuum plants is possible without reciprocal interference. The high voltage range can be changed during evaporation without influencing the emission nt or current or the position of the beam spot. Balzers High Vacuum Ltd Circle number 36 on Reader Enquiry Service card

Improved

pumping

system

for

milk

tankers

An improved exhauster compressor for use in milk collection tankers has been developed by Alfa-Laval’s Industrial Processes Division, in conjunction with the Farm Services Dept. of the Northern Ireland Milk Marketing Board. Called the VP76X compressor extractor unit, it has been specially designed for milk tankers of 2,000 gallons capacity and above. The system has been recommended by the Board’s transport fleet officer, for fitting to ail new milk collection tankers, and the replacement as necessary of older equipment on existing vehicles. The primary advantage of the new equipment, according to the Northern Ireland Board, is that it operates far more rapidly than alternative systems. It is possible to exhaust a 2,000 gallon tanker 4-5 minutes (less in some cases), as opposed to 10 minutes or more previously. This means that on routes where producers are in close proximity, it is possible to hold the vacuum in the tanker between uplifting points, cutting out the need to run the vehicle engine in farm premises. The fact that the VP76X unit and the blower are separated allows the use of an oil lubricated vacuum pump, whereas alternative pumping systems need to be oil free to avoid the risk, when used as a blower system, of introducing oil mist into the milk.

voltage is *I 0%. with a maximum The input current does not load conditions.

The positive output voltage may be preset and the maximum ripple and noise content peak-to-peak at maximum output voltage. better than 2% of output voltage for a load to full load, and line regulation is better than in the dc supply.

between 1 .I -1.5 kV, of the output is 500 mV Load regulation is change from zero 1 %for a *lO% change

The Model 455A will withstand intermittent short circuits and flashovers; input protection is provided by an internal 600 mA quick-blow fuse. The unit is suitable for use in ambient temperatures between O”-+5O’C, and at up to 90% relative humidity. Brandenberg Ltd Circle number 38 on Reader Enquiry Service card

New

panel

mounting

kit for

The standard 2 in. (51 mm) diameter from Schrader Pneumatics, can now new and inexpensive panel mounting

air pressure

gauges

range of air pressure be supplied complete kit.

gauges with a

The kit, which uses a simple two-screw compression fitting, is also suitable for other types of gauge or meter requiring a 2 in. (51 mm) panel cut out, and is available separately. Schrader standard gauges come in 3 pressure ranges and are calibrated in both psig and bar measurements. All have $ in. BSP tapered threads. The ranges are : O-60 psig (O-4 bar), O-200 psig (O-14 bar) and O-300 psig (O-20 bar). Two non-standard (O-l 4 bar) with (O-l 4 bar) with

New

seal

versions are also available : O-200 psig an & in. BSP tapered thread, and O-200 psig side port. a 2 in. BSP taper threaded Schrader Pneumatics Circle number 39 on Reader Enquiry Service card

user’s

design

kit

A new kit containing 4 ultra compact ferrofluidic exclusion seals is now available from Ferrofluidics Corp. The designers may mix-and-match from among any of 7 sizes at his option. EX-4 kit also includes instructions, ferrofluid sealant and applications brush. EX-exclusion vapour, dust,

seals are specially designed particulates, oil contaminants

for exclusion of water and abrasives. 249

Vacuum

News

Applications include textile spindlesglass grinding, disc drives, rotary clutches, electric motors encoders, ice making machines-anywhere that hermetic operation can upgrade reliability and extend life. Standard EX-series units range in sizes from f in. to 13 in. shaft diameters. Seal cross section is only & in. x & in. allowing seal to be used in many retrofit applications as well. Ferrofluids Corp. Circle number 40 on Reader Enquiry Service card

Demonstration Hoy Carbide

of Scot Vat furnace

complex

at

Twenty four representatives from British hard metal producing companies attended a seminar on the new Scot Vat tungsten carbide de-waxing and sintering furnace complex at Hoy Carbides Ltd. The furnace, which was designed (Scotland) Ltd, and manufactured Redlac Ltd, contains many unique

by Vacuum Engineering by their associate company features.

It consists of 2 de-waxing furnaces and 2 sintering furnaces. The furnaces are designed to take a charge of 11 in. x 16 in. high and provide 3 heats each in a 24 h period. The complex is fully automatic and is easily capable of producing 1 ton of hardmetal tips per week. The complex has a circular formation with two sintering furnaces each flanked by a de-waxing furnace with a wax collection plant. At the centre is an air-operated hydraulically-assisted carousel loading gear, with a fork-lift mechanism to load and unload the 4 furnaces. Charge handling and the possibility of mechanical damage is therefore reduced to a minimum and little physical effort is needed so female labour can be employed. Operation of the complex is fully automatic, with manual over-ride. All controls are centred in one cubicle and each cycle is pre-planned on the programme control equipment. A 12 point instrument continuously records temperatures in all 4 furnaces and pressures in the sintering furnaces. Mimic diagrams display the cycle stage in each furnace. Interlocks and safety devices protect the complex from failure of services at any part of the cycle. Vacuum Engineering (Scotland) Ltd Circle number 41 on Reader Enquiry Service card

New

range

of stainless

steel

pneumatic

regulators

Designed for use in Chemical Plants, Refineries and similar aggressive and corrosive environments, a new range of stainless Air Pressure Regulators and Filters from LG International have impressive specification.

steel an

The Regulators are designed to maintain an extremely stable and precise pre-selected air pressure, with varying inlet pressure and load requirements. The design of the balanced diaphragm allows fast and accurate response to the screw setting adjustment; a self-relieving feature is standard. An optional micron is incorporated also a pressure gauge of 50 or 63 mm scaled in psi, bar or kg/cm*. Inlet pressure is maximum 150 psi and two models are available for different output ranges. Type 1 = O-50 psi ; Type 2 = O-l 00 psi. Both models can be mounted directly into the line alternatively surface or flush panel mounting plates are supplied. LG International Circle number 42 on Reader Enquiry Service card 250

Microcomputer brings ease of use to AA

unmatched

versatility

and

The Perkin-Elmer Model 460 double beam atomic absorption spectrophotometer combines the latest developments in microprocessor electronics with Perkin-Elmer’s years of experience in atomic absorption. Much of the superb speed and ease of use of the 460 results from the use of a microprocessor, the miniature electronic ‘brain’ which has made possible the new generation of high-powered microcomputers and calculators. Microprocessor electronics make it possible to implement complex calculation and logic programmes simply, quickly and accurately. The Model 460 provides integrated readings in absorbance, concentration, or emission intensity which can be updated continuously or held on the instrument display. Integration times from 0.2 to 60 s can be selected by the operator by merely keying in the desired value on the numerical keyboard and pushing the INTegration time button. The Model 460 can also measure peak height or integrated peak area for determinations with flameless sampling devices and can be used for flame emission as easily as for atomic absorption. The versatility and convenience of the Model 460 is further enhanced by its 6 digit electronic display and compatibility with recorder, printer sequencer or teletypewriter readout facilities. There is also a Double Beam Background Corrector which can be used in conjunction with the element light source for readings simultaneously corrected for background absorption, or else used alone for background only measurements. There is a safe, versatile gas control system incorporated as a standard feature in the Model 460, which provides pressures and flow adjustment and metering. A built in ignition interlock, burner head safety interlock and an automatic nitrous oxide switching system ensure complete safety of operation. However, there is also the option of a high convenience gas control system which provides even more sophisticated features such as pushbutton controls, automatic gas sequencing, automatic flame and pressure sensing, status indicator lights and provision for three oxidant and two fuel gases. Perkin-Elmer Ltd Circle number 43 on Reader Enquiry Service card

First

automatic

sampling

system

for flameless

AA

Perkin-Elmer have just introduced the Model AS-l Automatic Sampling System for flameless atomic absorption spectroscopy. This is the first automatic sample dispenser to be made commercially available for flameless AA and provides many benefits including a higher sample throughput and increased level of precision. With the Model AS-l, up to 30 samples can be analysed discretely once, or as many times as required. The automatic system controls the set programme for the HGA graphite furnace, the AA Spectrophotometer and the sequential numbering on a digital printer, so that a completely automated work station for flameless AA can be established. Two of the greatest advantages for laboratories using this system are the reductions in operator costs and also in the degree of operator skill that would be required for manual sample dispensing. Use of the Model AS-l ensures accurately and precisely dispensed volumes of sample, extremely low risk of contamination as the pipette tip is washed automatically, and repeatable placing of the sample droplet into an exact position in the graphite tube. With the possibility of operator error or fatigue totally eliminated by the automated system, the coefficients of variation for the majority of elements lie below 0.5% and an extremely high level of analytical precision can be achieved. Perkin-Elmer Ltd Circle number 44 on Reader Enquiry Service card