devices for sampling and concen trating impurities. Water of this high purity is achieved by ion exchange demineralization and deaeration plus care ful handling and storage in resist ant equipment. Even in subcritical plants, re quirements are high. Electrical re sistance of 18,000,000 ohm-cm. is attained regularly. This is higher than that obtained in several labor atory distillations using quartz ves sels. In nuclear energy plants, high purity water is needed, as dissolved solids might become radioactive from circulating in the nuclear re actor. In this application, not only must the water be very pure but the materials of construction used must be of a type which will not intro duce objectionable metallic ions or particles into the coolant stream. Purification steps for water for nuclear reactor use consist of a se quence of cation exchange soften ing, evaporation, mixed bed deionization, decarbonation to remove carbon dioxide gas, deaeration, and finally the "zero treatment" with hydrazine to reduce oxygen concen tration to practically zero. Many other industries require high purity water. In the manufac ture of transistor and television tubes, impurities in the parts per billion range can cause serious de fects in the end product. In the manufacture of pharma ceuticals, USP specifications limit dissolved solids to 5 p.p.m. In the photographic industry high purity water is essential in the manufac ture of paper, film, gelatin, etc. In making ceramics, impurities in water leave marks in the final product; in porcelain enamel, such impurities affect the workability of the enamel; in electroplating, dis solved materials create problems. For a common material taken for granted by so many, water is cer tainly no common material to the chemist. If recent history is any indication, more effective means of purifying water will be needed and methods for determining its purity will have to become more sensitive.
HEVI-DUTY "Multiple Unit"
CRUCIBLE FURNACES Temperatures to 2300° F. Designed for •
Melting Small Quantities of Metals
•
Pyrometer Calibrations
•
Heating All Materials Contained in Crucibles
Laboratory technicians using Hevi-Duty Crucible Furnaces find they give the de pendable service demanded by exacting re search. Improved insulation and sturdy, long-life heating element construction are a few of the advantageous features. MU CRUCIBLE FURNACES TO 1850° F.
Write for Bulletin 1246.
Chamber Heating
Type
Dia.
HOT CRUCIBLE FURNACES TO 2300° F. HDT-304*
3"
χ 4"
$170.00'
HDT-506*
5"
χ 6"
270.00*
HDT-812*
8" χ 12" * Requires α Transformer.
430.00*
Furnace Price
Deep
82
2%"x4"
84
3"
$ 47.50
86
3"
χ 5"
71.00
506
5"
χ 6"
110.00
58.00
x3'/2"
FOR GENERAL AND SPECIALIZED LABORATORY APPLICATIONS
Hevi-Duty
"G-07-PT" FURNACE temperatures to 2600° F. This furnace is designed for high-temperature work where accurate control and uniform ity a r e i m p o r t a n t . Controls, which provide 48 temperature gradients, and an indicating pyrometer a r e located in the pyramid base. For greatest uni formity in the heating chamber, three heating elements are in stalled o v e r a n d t h r e e a r e beneath the refractory muffle. Write for Bulletin 957 for full details. Type
Watts
Chamber W.
L.
G-07-PT 4" 3500 7" •Operating voltage either 115 or 230 A.C. only.
HEVI-DUTY HEVI-DUTY
$585.00
Β TP
A DIVISION OF
C
ELECTRIC
Industrial Furnaces and Ovens. Electric and Fuel
Price
H.
23
