This invention relates to an airflow distribution system where air is discharged from a relatively thin or shallow plenum chamber into a relatively large work space, chamber, or duct.
One application for this invention is in industrial ovens. Typically, there is a thin, shallow plenum on one or more sides of the oven housing, each with an apertured distribution plate directing air into a relatively large, central work chamber where products are supported for operations such as drying, baking, sterilizing, preheating, dehydrating, and curing.
Uniform air distribution within the oven work space is very important in order to maintain uniformity of temperature and processing times throughout. Conventional ovens have had serious drawbacks from the standpoint of uniformity. FIG. 8 is a schematic representation of typical prior art ovens. This is a composite representation showing, on opposite sides, examples of two conventional air distribution plates which have been used prior to the present invention.
In FIG. 8, the oven 20 has an inlet 22 with heating coils 24. Air flows to relatively thin, shallow plenum chambers 26 and 28 and passes through distribution plates 30 and 32 into a work chamber 34 from which it exits through outlet 36.
Most of these prior art ovens have air distribution plates such as that designated 30 for plenum chamber 28 in FIG. 8. It has an array of openings 38. Typically, the air direction and velocity in the shallow plenum chamber 28 carries through the openings 38 into the work space 34 as shown by the arrows 40 in FIG. 8. The angular components of the individual air streams passing through openings 36 are clearly indicated by arrows 40. Another drawback of openings 38 is that they are not adjustable.
Other prior art ovens have air distribution plates such as that designated 32 shown on the left side of FIG. 8. It has an array of openings 42 each with an angled tab or louver 44. All the tabs or louvers are bent in the same general direction. Airflow is adjustable by bending the tabs and flows into the work chamber generally parallel to the bent tabs in the direction of the arrows 46.
For both of the prior art distribution plates (30 or 32) shown in FIG. 8, the airflow into the work chamber is non-uniform causing heating and processing conditions to vary.