Temperature Humdity Chambers - What you Need to Know Before Purchasing.

Temperature Humidity Chambers are available from a number
of manufacturers such as Thermotron, Tenney, Espec, Blue
M, Despatch, Ransco, TestEquity, Associated
Environmental, Bemco, Cincinnati Sub Zero, BMA, Lunaire
etc. When purchasing a Temperature Humidity Chamber,
there are a number of things to consider amongst which
are:

(a) Minimum Internal Dimensions of Chamber. This will be
determined by the size of the product to be tested.

(b)Temperature Range required for the test you intend
performing. The maximum range of a Temperature Humidity
Chamber is normally from -73C to +200C. However, to
accomplish this complete range the chamber will need to
have two compressors in what is referred to as a "cascade
refrigeration system". If only one compressor is used,
then a temperature range of down to approximately -35C is
possible. Remember though that humidity testing can not
be performed below 0C (freezing point) and that any
testing below 0C will be possible for temperature only
testing (humidity function will be disabled).
Temperature Humidity Chambers are also available without
any refrigeration at all. The lowest temperatures at
which testing can be performed without refrigeration is
normally about 12C above ambient.

(c) Humidity Range required for the test you intend
performing.
Although most Temperature Humidity Chambers claim that
they have a humidity range of 20% to 95%, what is often
overlooked is the temperature range at which these
humidity levels can be achieved.
For example, at 25C, the lowest humidity obtainable by
most chambers with refrigeration will be about 45%
(unless a dehumidifier package is installed). As one
increases the temperature above 25C, lower humidity
levels than 45% can be achieved. Normally graphs are
provided by the manufacturer indicating the temperature
versus humidity range of the chamber.

(d) Water Recycling System - If you do not have a drain
available to drain the excess water used to create the
humidity, you should consider a water recycling system
consisting of a water storage container, demineralizer
cartridge and recycling pump. This will recycle the
water so that a drain is not required. Remember,
demineralized water should be used for Temperature
Humidity Chambers, not deionized water!

This information has been brought to you by LR
Environmental Equipment Co. Inc. which carries the
largest inventory of Certified Refurbished Environmental
Test Chambers and Industrial Ovens in the World.

Should you require more information, they can be contacted at
800-574-2748. Purchased a Certified Refurbished
Temperature Humidity Chamber from a reputable company
such as LR Environmental who has been in business for
over 40 years can save you a fortune while removing the
risks when purchasing used.
http://www.lre.com/test/temperature-humidity-chambers/temperature-humidity-chambers-all.htm