Heat exchange – With timer – programmer – time delay – or condition responsive... – Having heating and cooling capability
Reexamination Certificate
2001-01-24
2003-01-07
Ciric, Ljiljana (Department: 3743)
Heat exchange
With timer, programmer, time delay, or condition responsive...
Having heating and cooling capability
C165S048100, C062S176600
Reexamination Certificate
active
06502629
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to conditioning the forced air of downdraft types of paint booths that are used in the automotive repair industry. Particularly, it relates to an improvement in management, conditioning and control of the air flow in order to improve and maintain comfortable working and breathing environment, thereby ensuring a better level of health and safety for painting personnel. Specific to the invention is the concept of emulating operation of a large-capacity cooling system with multiple smaller air conditioners.
2. Discussion of Relevant Art
Those associated with modern automotive body repair facilities are acquainted with Occupational Health and Safety Act (OSHA) requirements as they pertain to the work environment that must be maintained in the facilities used for painting. Foremost among the health and safety standards are those that deal with the handling, use and disposal of noxious paint and solvent fumes. To this end, there is extensive use of air moving and air conditioning equipment, including that for ventilation as well as humidifying, and heating or cooling the air for paint curing. Most paint facilities consist in rooms or booths that are spacious enough to enclose the object to be painted, while affording adequate space for one or two persons, with spray equipment, to move comfortably about the particular facility. In high production facilities, wherein the two cycles—painting and curing—are run throughout the workday, a cool down problem may occur in most locations in the temperate weather zone. This problem occurs primarily because the curing heat required in the facility (hereafter, “booth”) is not ameliorated rapidly enough to allow comfortable reentry by the painter(s). Ambient humidity and temperature, at the beginning of the day, are readily handled by most systems, during the incipient operation, but not as the day progresses. Consequently, personnel are often subjected to arduous working conditions which, on days of high temperature and/or humidity, create an issue of health and safety.
In this discussion of relevant art, I want to first describe the type of facility that I originally purchased and have subjected to the hereinafter discussed improvements. My booth is a product of S.A.I.M.A.; Arezzo, Italy, imported by Pippa Industries, Paterson, N.J. The equipment provision for this drive-in enclosure is, in the sequence of principal air flow: intake; air ducting; adjacent damper (not in the direct intake air stream); air mover; furnace; a ducting subsystem that communicates with both the intake stream (via an adjacent damper) and the booth ceiling (via a plenum); ceiling filtration; booth enclosure; floor filtration; and an exhaust duct, leading to ambient atmosphere. [There was no air conditioner provided in the original booth.]
During the “baking” or curing cycle, the personnel are evacuated and, by use of the control system, the furnace is activated for high(er) heat and the damper is positioned to partially re-circulate the heated air into the intake stream. Re-circulation of the heated air induces a rapid heat rise to acquire a metal temperature (of the vehicle) of 140° F. (60° C.). Immediately after the curing cycle, the air flow is restored and the damper is repositioned to reinitiate the “paint” cycle. In the original, unimproved system, booth cool down, from about 100° F. to about 75°, took an average of nine minutes or more, depending on outside temperature. During the paint spraying operation, a single air conditioner (“A/C”), that I retrofitted to the original booth, cycled an average of every four minutes, with temperature varying as much as 18° F. On the second painting cycle of the day, recovery to tolerable conditions for personnel was acceptable (about eight minutes). However, as the day progressed, and both ambient outside and equipment temperatures rose, the recovery time became protracted (to as long as, or longer than 20 minutes). Often, on humid days over 85° F., the air conditioning unit failed to recover sufficiently, requiring a shut down in operations and posing, for me, the most significant deficiency in my operation.
I cannot say how other systems, made by other manufacturers, perform; however, a relevant art search has shown the equipment and techniques employed by them and prompted me to disclose my recent improvements.
The systems of interest are downdraft types that essentially provide air through the overhead structure and exhaust through the floor on which the work piece resides. U.S. Pat. No. 5,213,259, issued for Paint Booth Humidity and Temperature Control System, is directed toward a humidity control system that uses a water spray nozzle to rapidly alter the humidity and, consequently, the temperature of air taken into a paint booth through its ceiling. The air is drawn across the work piece, front to rear, and exhausted through the same ceiling. Being of a substantially different draft type than required by my operation, this system is noted only in that no provisions appear to have been made for balancing personnel comfort against high productivity requirements. In U.S. Pat. No. 5,127,574, issued for Spray Booth for Applying Coatings to a Substrate and Control Device Therefore (sic), shows a down draft type paint system that uses an open booth, similar to a laboratory hood, save for the downward flow. It displays only a spraying apparatus and, absent a heat curing setup, is not fully within the purview of my invention. U.S. Pat. No. 3,979,535, issued for Process for the Spray Application of Aqueous Paints by Controlling the temperature of the Air in the Paint Spray Zone is relevant in that it discloses a system for modifying spray air during the painting cycle. This technique is inapplicable to the treatment of booth air, in general; it is cited because it discusses the relationship that environmental humidity bears to ambient temperature and the coating (painting) process.
Two patents having similar tangential relevance, in that working persons are not of particular concern nor employed, are U.S. Pat. Nos. 4,367,787 and 4,616,594, issued for Air Conditioning Apparatus and Method for Paint Spray Booths and Painting Booth, respectively. The first of these consists in a single air conditioner system that uses a multiply-sectioned heat exchanger and partitioned air flow treatment to effectively recover and conserve energy while providing a customized mix of conditioned and unconditioned (bypassed) air to a paint booth (not disclosed). The second employs a single air conditioner, but is concerned only with providing temperature and humidity controlled air to an unmanned or robotic system, and within a very small zone. Of particular interest to me is its similarity to my present system, but for lack of a human element and the sparseness of the area of work.
A most notable deficiency with single, large-capacity air conditioners is that, with the requirement to maintain tolerable work conditions (by keeping the temperature environment within a few degrees), the cooling system must turn on/off frequently. This characteristic is deleterious to all machinery, irrespective of size.
INCORPORATION BY REFERENCE
In the aggregate, U.S. Pat. Nos. 4,616,594, 5,127,574 and 5,213,259 show many of the aspects of the original paint booth facility that I have improved for human comfort and safety, e.g., downdraft type, ceiling and floor filtration, at most a single air conditioner or partial re-circulation. All are hereinafter incorporated by reference.
DEFINITIONS
Terms used herein shall have their standard meanings which are taken ordinarily from the American Heritage Dictionary of the English Language 2000. In the case of a word or term to which is ascribed a particular meaning of art, the word will be used in context, defined, and setoff by quotation marks (“)
BRIEF SUMMARY OF THE INVENTION
I have succeeded in i
Ciric Ljiljana
Morelle Fredric T.
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