Electronics-World-1959-05

www.americanradiohistory.com
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9. Beaded Channel leg (Will not rust
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40 FT. HIGH
LIST
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OTHER MODELS FROM I FT. TO El FT.
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How
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WRItE
today for complete hter
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550 West earner Street Frankfort, Indiana
IN CANADA. Delhi Metal Products Co., Delhi, Ontario
14
OUR "SOUND" CHART
To the Editors:
With reference to your February
issue, we would like you to send us
50 copies of the "Sound" fold -out
page. We are exclusive RCA Industrial
Sound Contractors, and these
would be of tremendous value to our
technicians.
ROBERT MARTIN, President
Otto K. Olesen Electronics Inc.
Montebello, California
To the Editors:
We would like to compliment you on
the design chart entitled "Sound" in
your February issue. This is indeed an
excellent presentation and is especially
helpful in my occupation.
In fact, I liked this chart so much
that I would like to distribute copies
to my staff. I would, therefore, be
most appreciative if you could provide
me with 30 additional copies.
LESLIE C. HEARTZ
Colonel, USAF
Deputy for Communications
& Electronics
United States Air Force
Richards -Gebaur Air Force
Base, Missouri
To the Editors:
Can you tell me what you would
charge for 3000 to 5000 reprints of the
"Sound" gatefold?
HAROLD GLICKMAN
Harold Glickman Advertising
Boston, Massachusetts
We were certainly pleased with the
excellent response that this gatefold
produced. Single copies of the chart
are available at a price of $.15 each
while a lower cost is available on
quantity orders. Address your inquiry
to the Editorial Department of ELEC-
TRONICS WORLD, One Park Art-nue,
New York 16, New York. -Editor.,.
"SPRA -KOAT CIRCUIT COOLER"
To the Editors:
In Mac's Service Shop in your January
issue, mention is made of General
Cement's "Spra -Koat Circuit Cooler."
I would like to express deep concern
about the use of this "Freon" gas. My
trade is refrigeration and I have a
strong basic knowledge of the various
refrigerants that are used. The manufacturers
of "Freon" give many wonderful
characteristics of this gas as
compared to others used for refrigeration.
However, they fail to mention
that when exposed to open flame or
high heat, "Freon" may break down
into toxic gases of chlorine and phosgene.
Spraying a cloud of gas onto a
hot tube may wreck the envelope and,
from our Readers
if the serviceman is in a small area, the
toxic gases produced may be very
dangerous.
Also. if the technician is smoking,
this may be disastrous, especially if one
man tries to demonstrate the effect of
a cold north wind on the back of another
man's neck at the same time.
Finally, if the container is inverted,
there is a chance of squirting a stream
of liquid "Freon" which will burn the
skin.
HENRY BOYCE
San Leandro, California
Although Mac's Service Shop did
point out quite a few of the precautions
mentioned by Reader Boyce, we forwarded
his letter to General Cement.
They in turn sent it along to Du Pont's
Freon Products Division. A small portion
of their reply is as follows.-
Editors.
Dear Mr. Boyce:
Your experiences with "Freon" refrigerant
and the anticipated experience of
someone using "Freon" from the "Spra-
Koat Circuit Cooler" package are quite
different. It is true that, although the
"Freon" compounds are nonflammable.
practically odorless. and are virtually
nontoxic, they do decompose when
heated to sufficiently high temperature.
In the case of "Freon -12," the temperature
of decomposition is just slightly
over 1000 °F, as shown in the Underwriters'
Laboratory report attached. It
is true that the portion of "Freon-12"
which is exposed to this temperature or
higher will decompose into halogen
gases, including hydrogen fluoride, hydrogen
chloride, and slight traces of
phosgene. These gases give ample
warning of their presence because of
their extreme pungent odor. The circumstances
in refrigeration service
work which are most responsible for
producing these halogen products are
the conditions where a halide torch is
used for refrigerant leak detection or
when service lines containing refrigerant
gas are being soldered or welded.
In this latter condition, I might also
point out that the decomposition products
of certain soldering fluxes, lubricant,
and miscellaneous materials also
produce unpleasant and sometimes
dangerous -to- inhalation gases. For this
reason, it should be a part of every
refrigeration serviceman's training
that whenever leak testing or soldering
operations are to be carried out on refrigeration
equipment, adequate ventilation
must be supplied.
The situation is quite different when
using the "Spra-Koat Circuit Cooler."
First of all, the temperature of hot
parts in radio and television equipment
ELECTRONICS WORLD