Ventilation – Workstation ventilator – Spray booth
Patent
1993-05-28
1995-03-07
Joyce, Harold
Ventilation
Workstation ventilator
Spray booth
454 53, B05B 1512
Patent
active
053952855
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to an apparatus and method of dehumidifying a body of air within a chamber.
A number of processes suffer because the chamber in which these processes are performed has too great a moisture content. Such processes include the spray painting of articles such as vehicles in a spray booth.
Venting the spray booth may be sufficient where the chamber has been used to prewash, for example, a vehicle because the humidity outside the chamber is lower than inside the chamber and therefore the humidity can be reduced to equal that of outside the chamber. However frequently the humidity outside of the chamber is sufficiently high to adversely affect the quality of the finish achieved and it is desirable to further reduce the humidity of air within the spray booth, and simply venting air through the booth does not achieve a sufficient reduction in humidity.
One method of decreasing relative humidity under these circumstances is the provision of a cooling plate wherein a refrigeration unit is used to cool the cooling plate so that moisture condenses out of the air within the chamber, and is then diverted into a collecting tank or a drain. A problem with this means of removing of moisture from the chamber is that the provision of a refrigeration plant is expensive, bulky and is energy consuming to operate.
One object of this invention is to provide an arrangement or a method for reducing relative humidity of a body of air within a chamber in a simple yet effective manner.
A further object of one form of this invention is to provide for a method of spray painting with reduced relative humidity.
SUMMARY OF THE INVENTION
The invention could be said to reside in an arrangement for reducing relative humidity a body of air within a substantially sealed chamber, said sealed chamber including an external recirculating duct positioned to recirculate said body of air through the chamber, a heater means to heat the air either in said duct or said chamber, said duct including an inlet and an outlet with air flow directed from the chamber into the inlet and out of the outlet into the chamber, said duct having an exchange aperture opening to an outside and located between the inlet and outlet and so positioned that a reduction in relative humidity is achieved on heating and recirculating the body of air through the recirculation duct with substantially no ingress of air from outside.
Preferably said exchange aperture faces the direction of air flow in the recirculating duct, the fan means being positioned downstream of the exchange aperture to draw air away from the exchange aperture.
Preferably the direction of airflow approaching the exchange aperture is upwards, and changes direction to leave the exchange aperture lateral to the initial direction.
Preferably the heater means is located within the duct and downstream of said exchange aperture.
It is found in such an arrangement that the relative humidity drops upon heating of the air and upon recirculating of the air through the duct and past the exchange aperture. The drop in humidity within such a chamber with the heating and recirculation of the air is greater than expected simply with the increase in temperature.
An explanation of this phenomenon is not entirely clear however experimentation has shown that the provision of the aperture facing the direction of air flow in the first portion of the duct appears to be crucial to the invention. The provision of a negative pressure in the second portion of the duct so that air is pulled into the second portion appears to have a beneficial effect.
It would seem likely that the air drawn through the first portion of the duct in part mixes with colder air from the environment immediately outside of the aperture, so as to have a condensing effect at the interface therebetween, the condensed moisture being dissipated into the atmosphere from immediately outside of the aperture. The exchange aperture being positioned to face the outside environment enhancing the mixing and condensation
REFERENCES:
patent: 1748863 (1930-02-01), Burke
patent: 2440627 (1945-08-01), Bahnson, Jr.
patent: 2517499 (1950-08-01), McGrath
patent: 3395972 (1968-08-01), Hardison
patent: 4587427 (1986-05-01), Beierling et al.
patent: 4987952 (1991-01-01), Beal et al.
Joyce Harold
Monarch Industries (Aust) Pty. Ltd.
LandOfFree
Dehumidifier does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dehumidifier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dehumidifier will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1402914