Abstract:
An arrangement for drying material in a selected drying location by a heated and flowing drying stream wherein the temperature and relative humidity levels of the drying stream are sensed upstream and downstream of such selected drying location and are relatively and comparatively controlled to arrive at a selected treated material moisture with comparatively minimal energy input.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a material drying arrangement and more particularly to a unified apparatus and method for drying materials such as fabric in a selected location with a drying stream modulated in flow and temperature by a blower and heating member, respectively, which are controlled in accordance with coordinated sensed upstream and downstream temperatures and relative humidity. 
     It is known in the prior art to utilize dryer apparatus responsive to either or both sensed temperatures and relative humidities. In this regard, attention is directed to U.S. Pat. No. 4,086,707, issued to S. Bochan on May 2, 1978, U.S. Pat. No. 4,231,166, issued to S. L. McMillan on Nov. 4, 1980; U.S. Pat. No. 4,267,643, issued to J. C. Hariedon on May 19, 1981 and U.S. Pat. No. 4,891,893, issued to R. K. Narang on Jan. 9, 1990. These four patents teach various arrangements for clothes dryers responsive to sensed temperatures in heated drying air. Attention is further direct to U.S. Pat. No. 6,079,121, issued to P. S. Khadkikar, et al, on Jun. 27, 2000 and U.S. Pat. No. 6,122,840, issued to N. W. Chbat et al on Sep. 26, 2000, both of which teach arrangements wherein clothes dryers are responsive to humidity changes. In addition, attention is directed to the three U.S. Pat. No. 5,315,765, issued to M. Holst et al on May 31, 1994, U.S. Pat. No. 6,098,310, issued to Y-T Chen et al on Aug. 8, 2000 and to U.S. Pat. No. 6,141,887 issued to Y-T Chen et al on Nov. 7, 2000, all three of which patents teach clothes dryer arrangement wherein clothes dryers are responsive to both sensed temperatures and humidities—it being noted that U.S. Pat. No. 5,315,765, senses temperature and humidity at both clothes dryer intake and exhaust. Finally, attention is directed—as of general interest—to the clothes dryer arrangements of U.S. Pat. No. 4,546,554, issued to N. J. Bullock et al on Oct. 15, 1985 and U.S. Pat. No. 6,115,680, issued to W. D. Barritt on Sep. 19, 2000, it being noted that the majority of the above referenced patents are directed to clothes dryer structure adapted in residential usage wherein clothes drying loads are substantially less than the larger loads familiar in commercial drying situations. 
     The present invention provides a unique material drying arrangement which can be utilized for both commercial and residential drying, which provides a novel healing and ventilating arrangement requiring a minimum of novel parts to construct and maintain and which provides a minimum of novel steps to operate. The present invention further provides for comparatively more efficient, economical, and straight forward operational control with a comparatively larger energy savings, efficiently utilizing less energy with the efficient consumption of lower amounts of gas and electrical energy. 
     It is to be understood that various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein. 
     BRIEF SUMMARY OF THE INVENTION 
     More particularly the present invention provides a unique and novel material dryer apparatus including a housing with a drying basket disposed therein and having a drying stream heater and blower associated therewith, a control arrangement for the dryer apparatus comprising: temperature sensing means disposed to sense the drying stream temperatures entering upstream and exiting downstream the drying means; relative humidity sensing means disposed to sense the drying stream relative humidity entering upstream and existing downstream the drying basket; and control means connected to the temperature sensing means and the relative humidity sensing mean, the control means being connected to the heater and the blower to cooperatively and intermittently modulate drying heat input and drying stream volume delivery in the heater and the blower with respect to each other and in accordance with sensed temperatures and relative humidity levels entering upstream and exiting downstream the said dryer basket. 
     Further, the present invention provides a unique and novel method of drying material to a selected moisture level comprising: introducing the material in a drying zone; measuring the temperature and relative humidity of a material drying stream passing through the drying zone along both at the upstream inlet and downstream outlet of the drying zone; and cooperatively and intermittently controlling the heating and flow of the drying stream passed through the drying zone with respect to measured upstream and downstream temperature and relative humidity whereby material removed from said drying zone has a select moisture level for further treatment with selected drying of the material being accomplished at an optimal energy level. 
     It is to be understood that one or more changes can be made by one skilled in the art in one or more of the several parts of the apparatus disclosed herein and in one or more of the several steps of the method disclosed herein without departing from the scope or spirit of the present invention. Further, it is to be understood the unique and novel unified apparatus and method as disclosed is not to be considered as limited to fabric treatment such as clothing or garments but can be utilized in other heating and ventilating environments where temperature and relative humidity control are involved. Moreover, although the unified arrangement herein disclosed has significant energy saving capabilities in commercial environments it would also have such similar capabilities in residential environments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which disclose a schematic arrangement of one embodiment of the present invention: 
     FIG. 1 is an isometric, broken away partial view of a portion of the novel drying apparatus of the present invention, disclosing portions of the front, rear and one side of the novel drying apparatus; 
     FIG. 2 is a front end vertical view of the novel drying apparatus of FIG. 1; 
     FIG. 3 is a schematic broken away vertical side view of the novel drying apparatus of FIG. 1; 
     FIG. 4 is a rear end vertical view of the novel drying apparatus of FIG. 1; 
     FIG. 5 is a schematic, broken away, vertical front sectional view of the line of stream drying flow view of the novel drying apparatus of FIGS. 1-4, and; 
     FIG. 6 is a schematic, electrical circuit for the novel drying apparatus of FIGS.  1 - 5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the unique and novel commercial dryer arrangement as disclosed in the broken away, isometric view of FIG. 1, a rectangularly shaped dryer housing  2 , which can be formed from any one of several strong, substantially rigid materials, such as a suitably coated sheet metal, can be seen. Housing  2  serves to define a large drying chamber  3  and an upper chamber  4  partitioned by horizontal partition  5 . As can be seen in the broken away schematic view of FIG. 5, drying chamber  3  serves to include a motor driven, reciprocating rotatable perforated drying basket  6  which holds and rotates the materials to be heat dried. The materials to be heat dried are passed to dryer basket  6  through the hinged door  7  at the front end of housing  2 , the door  7  being provided with a transparent glass or plastic material viewing sealed porthole  8  (FIG.  2 ). 
     Again, referring to FIG. 1 of the drawings, the partitioned, upper chamber  4 , incorporates a gas feed pipe  9  feeding burners  10  (FIG.  5 ). Pipe  9  is connected to a suitable external gas supply source (not shown). Gas feed pipe  9  incorporates a gas valve  11 , which is controlled in an intermittent manner described hereinafter through a humidity and temperature control sensor  21  and  22  and which also is disposed in chambers  3  and  4 . Chamber  4  is provided with a rear chamber inlet  13  (FIG. 1) through which a suitable drying fluid to be heated, such as ambient air, can be introduced into chamber  4 . Chamber  4  includes a secondary chamber  14 , which serves as a heating unit with ambient air passing from chamber  4  into secondary unit  14  (FIG.  5 ). It is to be understood that fabric material can be inserted through hinged door  7  with porthole  8  (FIG. 3) into the motor driven, perforated, rotatable drying basket  6  (FIG.  5 ). 
     Disposed in the lower portion of chamber  3 , defined by housing  2  is a rotatable motor driven centrifugal blower  16  (FIGS. 1,  3 ,  4  and  5 ) which serves to draw a heated drying stream from gas heating drying chamber  14  into chamber  3  through motor driven rotatable perforated drying basket  6  over the fabric materials inserted into the drying basket  6  and ultimately through the blower inlet  17  of blower  16  (FIG. 5) and through exhaust outlet  18 , in housing  2  (FIGS. 1 and 5) the exhaust outlet of fan or blower  16  being connected thereto. 
     As can be seen in FIGS. 3 and 4 of the drawings, a temperature and humidity sensor  21  is provided in the lower drying chamber  3 , serving to sense the exhaust temperatures and relative humidity in compatible intermittent cooperation with temperature and humidity sensor  22  in upper chamber  4  above partition  5 , all in accordance with the present invention and the inventive circuitry described hereinafter. In this regard, it is to be noted that a suitable programmable humidity and temperature circuitry controller  23  is mounted on the upper front face of housing  2  (FIG. 2) and that a reversing motor inverter  24  (FIG. 3) is suitably mounted below partition  5  in the upper rear of housing or cabinet  2  (FIGS.  3  and  4 ), these two units  23  and  24  being an important part of the inventive circuitry  26  of FIG. 6 as described hereinafter. 
     In accordance with the present invention, it is to be noted that the blower motor speed for blower  16  can operate in the low frequency range of approximately thirty (30) Hertz (Hz) to a high frequency range of approximately sixty Hertz. The heater can operate in such embodiment in the high heating range of approximately one hundred eighty thousand (180,000) British Thermal Units (BTU) to the Low heating range of approximately seventy-eight-thousand (78,000) British Thermal Units (BTU). In this regard, it is to be further noted that control  23  can be provided with multiple relative humidity settings and temperature control settings which can range up to ten (10) relative humidity settings and for temperature settings in the Fahrenheit range of approximately thirty two (32) to one hundred ninety seven (197) degrees Fahrenheit (F°). It is to be understood that the High and Low intermittent frequency ranges and BTU ranges can be varied by one skilled in the art according with material and dryer demands. 
     Referring to the inventive circuitry  26  of the present invention, a three (3) phase (PH) line L 1 , L 2 , L 3  is disclosed capable of carrying two hundred (200) to six hundred (600) volts (v) is disclosed for use with commercial dryers. It is to be understood that the present inventive circuitry could be employed with lower voltage single or three-phase circuitry delivery. Lines L 1 , L 2 , L 3  can be seen as directly connected to fan or blower motor  27  for the centrifugal fan or blower  16  through normally open variable speed drive contacts  28 ,  29 , and  31  respectively. 
     Also, connected across lines L 1 , L 2  and L 3  is the basket motor  32  for rotation of the above-mentioned drying basket  6 . As can be seen, basket motor  32  is connected in parallel to fan motor  27  and to the three-phase lines L 1 , L 2  and L 3 , through line set  34 ,  35  and  36  and line set  37 ,  38  and  39  respectively, with suitable sets of normally open forward drive contacts  41 ,  42  and  43  and normally open reverse contacts  44 ,  46 , and  47  being employed in the two sets of line set  34 ,  35  and  36  and line set  44 ,  46  and  47 , respectively. 
     Connected across lines L 1 , L 2  of the three phase line L 1 , L 2  and L 3  through a twenty four (24) volt (v) step-down transformer  48  are step down lines SL 1  and SL 2 . Four lines,  49 ,  51 ,  52  and  53  extend between SL 1  and SL 2  and two additional lines  54  and  56  extend between line  53  and SL 2 . Connected in line  49  is the above-discussed controller  23  (PROHC). As above noted, this controller  23 , which is fastened to the front face of housing  2  (FIG. 2) serves to modulate the heat and blower  16  through temperature and humidity sensor  21 , located in chamber  3  of housing  2  and the temperature and humidity sensor  22 , located in upper chamber  4  of housing  2 . Extending along line  51  between lines SL 1  and SL 2  and within control  23  is a cycle switch  57 . Line  51  further includes an energy smart relay  58  positioned in line  51  outside dryer control  23 . Line  52  extending between lines SL 1  and SL 2  includes an air switch  59 , outside control  23 , a heat switch  61  within control  23 , and again outside control  23  but in line  52  are basket and bonnet thermostats  62  and  63  respectively. The basket thermostat can be appropriately positioned in chamber  3  of housing  2  proximate drying basket  6  and the bonnet thermostat can be appropriately positioned in chamber  4  of housing  2  above partition  5 . Also positioned in line  52  outside control  53  is a direct spark igniter  64 . Connected to igniter  64  is a line  66 , the opposite end of which line  66  is connected to line SL 2 . A further line  67  extends between line  66  and line SL 2 . Line  66  include an energy smart relay contact  68  and High BTU gas valve  69 . Line  67  includes parallel lines  67 ′ and  67 ″ connecting in parallel with Low BTU main gas valve  71  and a redundant gas valve  72 . 
     Positioned in line  53  extending between lines SL 1  and SL 2  outside dryer control  23  is a lint door switch  73  and a door reed switch  74 . A switch  76  within dryer control  23  serves, when closed, to energize in line  53  forward contactor  77 . In lines  54  extending between line  53  and line SL 2 , a switch  78 , also within dryer control  23 , serves, when closed, to energize reverse contactor  79  in line  54 —both contactors  77  and  79  being outside dryer control  23 . In line  56  which also extends between line  53  and line SL 2 , a fan or blower switch  81  for blower  16  is included in control  23  and outside control  23  in line  56  is a variable speed drive or frequency controller  82 . This variable speed drive  82  or frequency controller includes line  84  having an energy smart relay contact  83  connected in line  84  calling for High blower speed. 
     Finally, connected in the lower portion of dryer control  23  is a rotation sensor  86 , a line  87  including a door reed switch  88  and a lint door switch  89 . Dryer control  23  also includes humidity and temperature sensors  21  and  22 . 
     From the description of this electrical control circuit  26 , it can be seen that the inventive dryer arrangement is capable of a unique control wherein the heat and the blower  16  are efficiently controlled through cooperative intermittent modulation of sensed inlet temperatures and relative humidities which are modulated intermittently with sensed outlet temperatures and relative humidities—all in an efficient, straight forward manner with a minimum of parts and a minimum of operating steps and with a minimum of energy usage and cost. 
     In a typical operation of the inventive arrangement, the temperature and humidity sensors  21  and  22  located in chambers  3  and  4  respectively communicate the measurements of a dryer control  23  which averages these measurements to obtain an operative relative humidity and temperature. The controller  23  is provided with a select number of relative humidity settings—approximately ten (10)—and a definite number of settings for temperatures—between thirty-two (32) to one hundred ninety seven (197) degrees Fahrenheit (F°). At a preset relative humidity (switch point) controller  23  will switch a contact connected to variable speed drive  82 , which is connected to fan motor  27 , allowing the fan motor  27  to run on preset levels of frequency ranging from sixty (60) down to thirty (30) Hertz (Hz). At the same time, contacts also switch a two-stage High-Low gas valve arrangement in lines  66  and  67 —thus resulting in an approximately twenty (20) percent (%) gas usage savings. With the relative humidity switch point set at a High level, the inventive dryer starts with a High BTU input and a Low cubic feet per minute blower  16  input. When the sensors read a preset average relative humidity, controller  23  switches the two-stage High-Low gas valve arrangement so as to obtain a Low Heat input and switches the frequency drive controller to obtain a High cubic feet per minute (cfm) flow.