Shellab SHC28R-2 User Manual
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THEORY OF OPERATION
These humidity chambers are designed to maintain temperature and relative humidity at set
points controllable by the operator at the front panel. Air is constantly being circulated
through the chamber, monitored for comparison to set points and treated if necessary.
On all units, heating is done by electric resistance heaters that turn off and on for
temperature control. On the R units with cooling (SHC10R (HC9R), SHC10R-2 (HC9R-2),
SHC28R (HC30R), SHC28R-2 (HC30R-2)) the refrigeration compressor is continuously
active.
Chamber humidification is achieved by means of a low-pressure vapor generator injecting
water vapor into the chamber through a small orifice. The water vapor is introduced into the
chamber at the blower discharge.
It should be noted that even though the unit does incorporate an exhaust system to assist
in achieving humidity close to ambient, the unit has no way of achieving humidity lower than
that which the ambient environment will allow.
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