Abstract:
A gas dryer includes a first opening structure forming a cooling pathway fluidly connected to the first opening; a first thermoelectric device thermally connected to the structure forming the cooling pathway and a heat exchanger. A condensate drain is located near an end of the cooling pathway and configured to drain condensate formed when a fluid is cooled along the cooling pathway. A structure forming a warming pathway is located between the condensate drain and a second opening, and a second thermoelectric device thermally connected between the structure forming cooling pathway and the structure forming the warming pathway and connected to exchange heat between the cooling pathway and the warming pathway. A method of drying a gas is provided.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an air or gas dryer. More particularly, the present invention relates to a method and apparatus for drying air used in pneumatic tools. 
     BACKGROUND OF THE INVENTION 
     Pneumatic tools use compressed air to provide power to the tool. Pneumatic tools are often made of metal components that are susceptible to rust or other corrosion when in contact with moisture. As a result, it is desired that the air used in the pneumatic tools have the moisture in the air removed as much as is practical. Often air used in pneumatic systems may be dried using desiccants. However, when a dew point is over 32° F. mechanical refrigeration is often used. Mechanical refrigeration cools the air which then lowers the dew point. As the air cools, the moisture in the air will condense. The condensate can be separated from the air. The air is then heated back up to a desired temperature. Thus heated air is considered a dry or dried air due to the fact that moisture originally found in that air has been removed. Standard mechanical refrigeration apparatuses involve high energy using components, such as, a compressor to compress a refrigerant which is later expanded as part of the refrigeration cycle. In addition, the use of refrigerants may be undesirable due to potential environmental harm that may occur should the refrigerant leak. Further, mechanical refrigeration systems include many moving parts which wear and need to be maintained and/or replaced over time. As a result, it may be desired to dry air by cooling it and re-heating it without the use of a typical mechanical refrigeration system. 
     Accordingly, it is desirable to provide a method and apparatus that can cool and reheat air without the use of mechanical refrigeration systems. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by the embodiments of the present invention. Wherein in one aspect an apparatus is provided that in some embodiments provides cooling and in some embodiments heating of air and or to dry the air without the use of typical mechanical refrigeration systems. 
     In accordance with one embodiment of the present invention, a gas dryer is provided. The gas dryer includes a first opening; structure forming a cooling pathway fluidly connected to the first opening; a first thermoelectric device thermally connected to the structure forming the cooling pathway and a heat exchanger; a condensate drain located near an end of the cooling pathway and configured to drain condensate formed when a fluid is cooled along the cooling pathway; a structure forming a warming pathway located between the condensate drain and a second opening; and a second thermoelectric device thermally connected between the structure forming cooling pathway and the structure forming the warming pathway and connected to exchange heat between the cooling pathway and the warming pathway. 
     In accordance with another embodiment of the present invention, a method of drying a gas is provided. The method includes: directing the gas through a cooling pathway; removing heat from the gas in the cooling pathway with a first thermoelectric device to a heat exchanger; condensing a fluid out of the gas; draining the condensed fluid from the gas; directing the gas though a warming pathway; 
     removing heat from gas in the cooling pathway with a second thermoelectric device and inserting that heat into gas in the warming pathway. 
     In accordance with yet another embodiment of the present invention, a gas dryer is provided. The gas dryer includes a first opening; structure forming a cooling pathway fluidly connected to the first opening; a first means for moving heat device thermally connected to the structure forming the cooling pathway and a heat exchanging means; a means for draining a liquid located near an end of the cooling pathway and configured to drain condensate formed when a fluid is cooled along the cooling pathway; a structure forming a warming pathway located between the means for draining a fluid and a second opening; and a second means for moving heat thermally connected between the structure forming cooling pathway and the structure forming the warming pathway and connected to exchange heat between the cooling pathway and the warming pathway. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an air or gas dryer according to an embodiment of the invention. 
         FIG. 2  is an exploded perspective view of the gas dryer shown in  FIG. 1 . 
         FIG. 3  is an enlarged perspective view of some of the components of the air dryer shown in  FIGS. 1 and 2 . 
         FIG. 4  is a schematic diagram showing various components of the gas dryer and how the gas flows through the gas dryer. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments of the invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a gas dryer. 
       FIG. 1  illustrates an example embodiment of a gas dryer  10 . A gas dryer  10  may include a housing  11 . The housing  11  may be metal, plastic, or any other suitable substance. The housing  11  provides protection for the interior components of the gas dryer  10 . 
     According to some embodiments of the invention, the gas dryer  10  includes an air inlet  12 . The gas dryer  10  includes a chiller extrusion  13 . The chiller extrusion  13  maybe made of metal, such as aluminum. In some embodiments the chiller extrusion  13  is made of extruded aluminum. The gas dryer  10  also includes a heat exchanger  14 . The heat exchanger  14  may be a fin heat exchanger which includes fins  16 . Opposite the fins  16  on to the heat exchanger  14  is a hot side  18  which is abutted against a thermal electric device (TE device)  20 . 
     The chiller extrusion  13  terminates with a separator  22 . A separator  22  includes a separator bowl  24  and a separator end cap  26 . Located on the opposite side of the chiller extrusion  13  is a heating extrusion  30 . 
     In some embodiments of the invention, the heating extrusion  30  may also be made of extruded aluminum. In other embodiments of the invention, the heating extrusion  30  may be interchangeable and identical to the chiller extrusion  13 , the only difference being placement within the gas dryer  10 . In other embodiments of the invention the heating extrusion  30  may be different than the chiller extrusion  13 . The heating extrusion  13  connects to an outlet  32 . While the chiller and heating extrusion  13  and  30  are referred to herein as extrusions it is understood that the extrusions  13  and  30  are not limited to actually extruded parts, but may include parts that provide cooling and heating pathways made by any suitable technique. 
     In some embodiments of the invention compressed air or other gas is provided to the inlet  12  as shown by arrow A. The compressed air flows through one or more pathways defined by the chiller extrusion  13 . The gas or compressed air flows through the chiller extrusion  13 . The TE device  20  is provided electric current which causes the TE device on the side facing the chiller extrusion  13  to be cold and the side of the TE device  20  facing the heat exchanger  14  to be hot. Heat is transferred from the gas in the chiller extrusion  13 , into the cool side of the TE device  20 , and then eventually to the heat exchanger  14  and to the fins  16  of heat exchanger. The heat is then dissipated into the ambient air surrounding the gas dryer  10 . 
     As the air or gas flows through the chiller extrusion  13  and cools, moisture condenses and the condensate flows into the separator  22 . After the air is dried by the moisture condensing and draining into the separator  22  the air or gas flows into the heating extrusion  30 . In the heating extrusion, the air or gas is re-heated and then finally is let out of the outlet  32  is indicated by arrow B. 
       FIG. 2  shows and exploded view of the gas dryer  10 . As shown in  FIG. 2  the heat exchanger  14  has a hot side  18  and on the opposite side are fins  16 . The heat exchanger  14  allows heat from the hot side to flow into the fins  16  where the fins  16  contact the ambient air of the gas dryer  10  and dissipate the heat. The hot side  18  includes a flat side  33  which abuts against the TE device  20 . As shown in  FIG. 2 , the TE device  20  includes several TE chips  36 . While four TE chips  36  are shown, the TE device  20  may include any number of TE chips  36 , from one to any desired number. The TE chips  36  may be Peltier devices. One of ordinary skill in the art understands a Peltier device to operate in such a manner such that when provided a voltage, one side gets hot and the other side of the Peltier device gets cold. The TE device  20  is situated so the cold side of the TE chips  36  abuts against the chiller extrusion  13 , when the hot side abuts against the flat surface  33  of the heat exchanger  14 . 
     The separator  22  is comprised of a separator bowl  24  and a separator end cap  26 . A separator bowl  24  and a separator end cap  26  may be screwed together by threads  35 . The separator  22  may attach to both the chiller extrusion  13  and the heating extrusion  30  by separator screws  42 . 
     Insulation  38 , may be located in between the chiller extrusion  13  and the heating extrusion  30 . Hole  40  in the insulation  38  is provided and a second TE device  20  is located within the hole  40 . The second TE Device  20  may also include multiple TE chips  36 . TE chips  36  are oriented so that the cold side of the chip  36  is located against the flat side  34  of the chiller extrusion  13  and the hot side of the TE chips  36  is located against the heating extrusion  30 . 
     The outlet  32  is located in an outlet manifold  44 , which may be attached to the heating extrusion  30  by cap screws  46 . The inlet  12  is part of an inlet manifold  48  which may attach to the chiller extrusion  13  by cap screws  50 . Arrows A and B illustrate the direction of air or gas entering A and exiting B in gas dryer  10 . 
       FIG. 3  is a partial close-up view of the chiller extrusion  13  and the TE device  20  including the TE chips  36 . The chiller extrusion  13  includes threaded holes  52  which allow the cap screws  50  as shown in  FIG. 2  to attach the inlet manifold  48  to the chiller extrusion  30 . The chiller extrusion  30  also includes multiple passage ways  54 . The passage ways are shown as various slots which allow the air or gas to flow through the chiller extrusion  13 . In some embodiments of the invention, the passage ways  54  may be more or fewer than as shown and may have a variety of different shapes. In the embodiment shown in  FIG. 3  and the passage ways  54  are rectangular in cross-section and extend through the length of the chiller extrusion  13 . In other embodiments the passage ways  54  may have other cross-sectional shapes. Preferably the shapes of the passageways  54  are selected to promote heat transfer. 
     As mentioned above, the heating extrusion  30  may be interchangeable and thus identical in size and dimension and composition as the chiller extrusion  13 . Therefore, the description given with respect to the chiller extrusion  13  may also apply to the heating extrusion  30 . One of ordinary skill in the art would understand that the threaded holes  52  would allow the outlet manifold  44  to attach to the heater extrusion  30  in a matter similar to that discussed above with respect to the inlet manifold  48  attaching it to the chiller extrusion  13  with the cap screws  50 . 
     The chiller extrusion  13  also includes a flat surface  34  as discussed above. Also shown in  FIG. 3  is the TE device  20  comprising multiple TE chips  36 . When the TE device  20  is located against the chiller extrusion  13  or, as indicated in  FIG. 2 , against the heating extrusion  30 , a heat transfer paste may be applied to either or both of the extrusions  13  and  30  and the TE device  20  to facilitate heat transfer between the extrusions  13  and  30  and the TE device  20 . A heat transfer paste may also be placed between the TE device  20  and the flat side  33  of the heat exchanger  14 , shown in  FIG. 2 . 
       FIG. 4  is a schematic diagram of a gas dryer  10  having a fan  56  a controller  58 , and sensors  60 . As the gas enters the inlet  12  in the direction of arrow A, the gas moves through the passageways  54  (see  FIG. 3 ) in the chiller extrusion  13 , heat from the gas moves in the direction of Arrows D through the TE chips  36  into the heat exchanger  14 . Heat may also leave the gas in the chiller extrusion  13  by the second set of the TE chips  36  and move to the gas in the heating extrusion  30  as shown by arrows E. Heat leaves the heat exchanger  14  in the direction of arrows C. 
     In some embodiments of the invention, air flows over the heat exchanger  14 , this air flow is provided by the fan  56 . The fan  56  is an optional feature and not all embodiments may include a fan  56 . 
     The fan  56  may be controlled by a controller  58 . A controller  58  may be operably connected to various sensors  60 . Depending upon the data provided by the sensors  60 , the fan  56  and the TE devices  36  may be controlled by the controller  58 . The controller  58  may control the TE chips  36 , providing less or additional current to TE chips  36 . Controlling the TE chips  36  in this manner will cause more or less heat may be moved from the chiller extrusion  13  to either the heat exchanger  14  or into the re-heater  30 . 
     Various TE chips  36  may be controlled as a block in a first set located between the chiller extrusion  13  and heat exchanger  14  and a second set located between the chiller extrusion  13  and the re-heater  30 . In alternate embodiments of the invention, each of the TE chips  36  may be individually controlled by the controller  58 . As the gas moves through the chiller extrusion  13  it cools and moisture condenses and drops in the direction of arrow G into the separator  22  as shown in  FIG. 1  and  FIG. 2 . 
     In some embodiments of the invention, the separator  22  may be connected to a hose or a drain or to drain the condensate away from the gas dryer  10 . Arrow G schematically represents the removal of the condensate from the gas in the gas dryer  10 . 
     The flow of gas from the chiller extrusion  13  is turned and moved in the direction of arrow F. Gas flows into the re-heater  30  (aka the heating extension  30 ). Arrows E show heat being removed from the gas and the chiller extrusion  13  and placed into gas located in the re-heater  30 . Removing the heat generated by the second set of TE chips  36  by using the coldest air or gas temperature rather than ambient air, the performance of these chips is enhanced and a lower air or gas temperature is possible with less energy expended. Insulation  38  is located between both the re-heater  30  and chiller  13  as shown and also maybe located between the re-heater  30  and the housing  11  (housing  11  is not shown in  FIG. 4  but is shown in  FIG. 1 ). The gas is then exited out of the outlet  32  in the direction of arrow B. 
     In some embodiments of the invention, the gas entering the inlet  12 , may be about 100° F. Gas may be cooled down to about 35-40° F. as it reaches the bottom of the chiller  13  just before it enters into the separator  22 . The air or gas may be reheated back up to about 100° F. in the re-heater  30  before it exits the outlet  32 . However, these mentioned temperatures are meant to be examples only, other temperatures may also be used in accordance with the invention. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.