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- Copyright
- Copyright © IOP Publishing Ltd
- ISSN
- 0950-7671
- DOI
- 10.1088/0950-7671/22/10/110
- Publisher site
- See Article on Publisher Site
Abstract
Physical Laboratory to the nearest I'O" C. They are: tin 232~c This firm announces that it has recently modified its standard lead 327' C., zinc 41g0 c., aluminium 659' c. and sodium chlo,.&' multi-colour ' L' recorder to incorporate a synchronous motor 801" C. The hypsometer tube (for 100' c. test) consists of 8 long drive from a.c. mains. This recorder is suitable for measuring UP closed metal vessel with an entry tube and escape vent at the top to six points, all the records being made on one chart in as many A flange on the outer tube fits into a recess at the top ofthe funace: different colours. The complete driving and chopper-bar mechanism When using this, and when it is desired to increase the rate of is now operated by means of a self-contained synchronous motor, cooling, a resistance with a ten-position contact arm is put in se,,is a separate master clock and rectifier being no longer necessary. with the furnace winding. The overall dimensions of the apparatus are 144 in. high end Pyrometer Testing Furnace. Wild-Bafield Electric Fur- 101 in. in diameter. naces Ltd., Elecfurn Works, Watford By-Pass, Watford, Presswe Sealing Zip Fastener. The B. F. Goodrich Herts. Company, Akron, Ohio, U.S.A. This equipment is intended for tests of pyrometers according to the British Standard Code 1041-1943, by the primary or freezing- The Pressure Sealing Zipper is a new rubber constm&,n point method of determination. The furnace has a rolled cylindrical applied to metal slide fasteners which makes them waterproof and steel case for floor or bench prevents escape of air or gases. The construction is of overlappi,,g mounting housing an intemally rubber lips which have such initial pressures built into them that grooved refractory chamber they seal against any pressure which the structural strength of the backed by insulating brick. A slide fastener will withstand. The lips are placed on either side of lifting handle is provided on the the article to be sealed, depending on where the pressure is exerted. case. The heating element con- Used on the outside they make the article waterproof and prevent sists of a helix of high-grade the entrance of air or gases. Used on the inside they prevent the nickel chromium alloy, carried escape of air, gases, or liquids held in the vessel. in the grooves of the inner re- Three pressure-seal zipper styles are being manufactured, two fractory with lead-outs brought being of the non-separating type, the first sealing along its entin to a plug at the base of the fur- length but open at the top, the second sealing along its entire length nace. The furnace topis recessed and at both ends. In the first, which is used in such'applications and fitted with an annular heat- as exposure suits, the slider is operated from either or both sides; resisting plate to receive the in the second, originally developed as a closure for pressure vesseb, container. A light Elecfurnite it is operated from the side opposite the sealing lips. The third cover is provided to conserve construction is of the separating type, which seals for the entin heat, fitting over the furnace length but not at the ends, with the slider operating from either or opening and container. An ex- both sides. tension tube with a clip is provided for securing to the immersion tube when required. A sliding damper at the bottom of the furnace enables one to ac- celerate cooling when necessary. The furnace (1.5 kW.) is suit- Pressure Sealing Zip ]:astener able for operation on zoo/zgo V. single-phase a.c. and for a maxi- The new rubber Pressure Sealing Zipper can be applied to mum temperature of 900" C. Pyrometer testing fumace metal, fabric, or sheet rubber, providing suHicient clearance ia The containers for the melts allowed for operation of rhe fastener. Installation can be BCCOIII- are of metallized mild steel, 7.4 in, diameter and 7 in. deep, flanged plished either by stitching or cementing, depending on the applim- at the top to hold them securely and centrally in the heating tion. The pressure seals, it is stated, are effective in a wide tem- chamber, and fitted with a handle for easy withdrawal of the con- perature range, not cracking when bent at -70" F., nor becoming tainer from the furnace. The container is designed to take a cover soft at 150a F. Weathering and ageing characteristics are stated to plate into which is welded a metallized mild steel immersion tube be excellent. It is pointed out that one of the great advantages of with a closed end held centrally in the melt and permanently fixed the sealing lip construction is that it conforms to changes in position to obtain the correct depth of immersion for its diameter. of the sealing wall, withstanding stresses caused by these move- The containers are supplied filled with high purity materials, the ments. freezing points of which have been certified by the National Correspondence THERMAL LAG IN FURNACE CONTROL AS soon as air transport facilities are available it is proposed bo Mr K. Hoselitz's use of a small mutual inductance to minimize the experiment with the transport of animal semen from this COU~ effects of thermal lag in furnace control (described in your May to such countries as Australia, East Africa, and South America. issue) is a useful and interesting application of the Gouy principle For this purpose it will be necessary to maintain the semen at I (J. Phys. Radium, 3rd series, 6, p. 479 (1897)). temperature of approximately +5' C for a period of about 8eW Readers who are interested in the theoretical aspects of the days. During this period extremes of temperature may be en. principle will find it discussed in relation to liquid expansion countered, in the air and at points of call in the tropics. Som8 regulators by Sligh (J. Aw. Chetn. Soc. 4a, p. 60 (1920)). means of maintaining a controlled low temperature will be necesaacg. Among other applications, the Gouy method is found in the The semen will be packed in a sealed glass vessel of about ZO~ Tirill vibrating voltage regulator, the Parsons 'puff governor' and capacity. The apparatus should be self contained, light and not some arrangements of astatic electronicvoltage regulators. Fairchild bulky and able to withstand vibration and shock. I should be gird (Instmmenzs, XI, p. 305 (1937)) discusses the advantages of the method. to receive suggestions from readers which will be treated in She ROOSEVELT GRIFFITHS confidence. Funds are available for experimental development. ARTHUR WALm Metallurgical Department School of Agriculture University College of Swansea Cambridge c 198 1
Journal
Journal of Scientific Instruments – IOP Publishing
Published: Oct 1, 1945