Patent Publication Number: US-2009221228-A1

Title: Wood stove radon reduction system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 11/423,180, filed Jun. 9, 2006 which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of wood stoves. 
     2. Description of the Prior Art 
     In certain areas of the country, radon collects in the basements of buildings. Typically, a blower connected to a collection tube extending outwardly from the building is operable to force the radon gas from the building. The collection tube may extend into the basement or beneath the basement or building slab. A blower is required adding not only to the initial cost of the system but also requiring maintenance and electricity. What is needed is a radon collection system that will use the heat within the heating system to force the radon from the building. Further, there is a need to combine such as system with a wood burning stove or candle burning due to likelihood of power failure in warm weather. Disclosed herein is such a combination and system. 
     U.S. Pat. No. 4,877,182 issued to Pugh et al. discloses a typical crawl space ventilation system to eliminate radon gas from the building. U.S. Pat. No. 4,905,579 issued to Dame discloses a plurality of blowers with control valves to control the pressure within the building thereby controlling the flow of radon into the building. U.S. Pat. No. 3,175,552 issued to Sutton discloses a wood burning fireplace having a blower motor for forcing air via the burning logs through the heating outlets extending throughout the room. In order to accelerate the draft out of the chimney of an incinerator, U.S. Pat. No. 3,134,345 issued to King discloses a blower for accelerating the draft through the chimney of the incinerator. Preheated air is ejected into the furnace combustion chamber in U.S. Pat. No. 4,262,608 issued to Jackson. 
     A number of combinations of heating systems and radon collection systems have been combined in an attempt to minimize radon gas within a building. For example, U.S. Pat. No. 5,191,874 issued to McWilliams discloses a blower for collecting radon gas from inside the building and then directing the gas to the gas outlet of a furnace. U.S. Pat. No. 4,244,686 issued to Scott discloses a method of improving the operating economy of a furnace by supplying to the heating chamber various gases including radon gas. Further, U.S. Pat. No. 4,920,866 issued to Hoban discloses the combination of a wood stove with a tube for collecting radon gas within a building which is injected into the outlet of the stove. 
     Wood stoves include a door which may be pivoted open for insertion of wood into the combustion chamber. By using such a stove, I have combined a radon collection tube which may be conveniently inserted via the door to direct the radon gas directly into the combustion chamber. Thus, the radon collection system may be conveniently connected or disconnected from the stove by positioning the radon collection tube through the door opening while at the same time inserting additional wood into the combustion chamber. 
     In moderate climates, the wood burning stove is not utilized to heat the building at all times since the outside ambient air is sufficiently warm not to require the heating of the interior air of the building. In these cases, wood burning stoves do not have wood burning within the combustion chamber at all times and instead the air within the combustion chamber is relatively cool. In such a condition, the stove does not expel radon from the building. I have therefore devised a method and heating system which utilizes a lighted candle within the combustion chamber when the chamber is void of burning wood and similar materials. A candle has sufficient heat to warm the gas within the combustion chamber thereby drawing the cooler radon gas within the radon collecting tube leading into the chamber; however, the candle does not generate enough heat to heat the building. Thus, the system is operable to remove radon from the building both when burning wood and heating the building and in a non-heating condition by placing a lighted candle within the stove. 
     SUMMARY OF THE INVENTION 
     One embodiment of the present invention is a stove for reducing radon gas in a building both when the stove is in a first condition heating the building and in a second condition not heating the building. The stove&#39;s main body has a combustion chamber and an opening leading into the chamber. A door is mounted to the stove&#39;s main body and is movable from a first position uncovering the opening to a second position extending across the opening. A radon collecting tube is mounted to the stove&#39;s main body and has a proximal end opening into the chamber and a distal end opening into the building. Burning wood is located in the chamber when the stove is in a first condition heating the building and gas within the chamber to draw radon gas from the tube into the chamber. A burning candle is located in the chamber when the stove is in a second condition not heating the building to heat gas within the chamber to draw radon gas from the tube into the chamber. 
     It is an object of the present invention to combine a wood stove with a radon collection system. 
     A further object of the present invention is to provide a new and improved wood stove. 
     Yet an additional object of the present invention is to provide a radon collection system that may easily be adapted to a conventional wood stove. 
     A further object of the present invention is to provide a heating system which is operable to withdraw radon from the building when the system is both in a heating mode and a non-heating mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a fragmentary schematic representation of the stove and radon collection system incorporating the present invention installed within a building. 
         FIG. 2  is an enlarged front view of the stove of  FIG. 1  with the stove door shown in the open position. 
         FIG. 3  is a side view looking in the direction of arrows  3 - 3  of  FIG. 2  with the radon collection tube removed from the stove. 
         FIG. 4  is the same view as  FIG. 3  only showing the stove door partially closed with the radon collection tube installed between the door and stove. 
         FIG. 5  is an enlarged fragmentary top view looking in the direction of arrows  5 - 5  of  FIG. 4  and viewed in the direction of the arrows. 
         FIG. 6  is a fragmentary and enlarged view of the radon collection tube  21  mounted in the stored position on the stove. 
         FIG. 7  is the same view as  FIG. 2  only showing a pile of wood on fire within the combustion chamber. 
         FIG. 8  is the same view as  FIG. 2  only showing a lit candle within the combustion chamber. 
         FIG. 9  is a top view of the stove of  FIG. 2  showing the cook top. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring now more particularly to the  FIG. 1 , there is shown in fragment a building  10  having a roof  11 , an interior room  12 , and basement  13 . A wood stove  16  is positioned within room  12  and has a conventional outlet flue  17  extending through the roof  11  to allow the exhaust gases from the stove to escape the building. A radon collection system  18  is provided to collect radon gas from the basement by a perforated tube  19 , in turn, connected by conduit  20  and tube  21  that extends between the stove door  30  and the main body  23  of stove  16  allowing the radon gas to enter the combustion chamber of the stove. A second conduit  24  extends through the roof  11  allowing gas collected by tube  19  to exit the building when valve  25  is positioned to allow the gas to flow from tube  19  through conduit  24  while blocking flow of gas into tube  20 . Likewise, valve  25  has a second position blocking flow of gas from tube  19  through conduit  24  but allowing the gas to flow from tube  19  through conduit  20  to tube  21 . An optional inlet tube  26  extends through the wall of the house to the external environment with a fan  27  provided to blow external air into the basement  13  thereby pressurizing the basement and forcing the radon from the building. 
     Wood stove  16  has a main body  23  positioned atop a base  28  ( FIG. 2 ) spacing the main body of the stove above the floor. A combustion chamber  29  is formed within main body  23  with exhaust outlet  17  leading therefrom. Door  30  is pivotally mounted by conventional hinges  31  and  32  to the front  33  of the stove. The door may be pivoted from an open position ( FIG. 2 ) through an intermediate position ( FIG. 4 ) to a completely closed position overlapping opening  34  leading into combustion chamber  29 . A handle  35  ( FIG. 1 ) is provided on the exterior surface of door  30  to facilitate the opening and closing of the door. 
     Wall  36  ( FIGS. 2 and 3 ) extends around opening  34  and projects outwardly from the forward facing surface  37  of the stove main body  23 . Wall  36  has a lower portion  38  and an upper portion  39  extending across respectively the bottom and top of opening  34 . Further, a pair of side portions  40  and  41  ( FIG. 2 ) extend vertically along the opposite sides of opening  34 . Portions  38  through  41  form a ledge  42  ( FIG. 3 ) that extends around the opening. Side portion  40  includes a recess  43  formed therein to receive tube  21  connected to the radon collection system. 
     Tube  21  may be removed from recess  43  to allow door  30  to extend sealingly across opening  34  with the exception that air is allowed to flow through recess  43  into the combustion chamber. When tube  21  is not mounted within recess  43 , it is stored in a vertical position in holder  45  mounted to the front surface  37  of the furnace main body. Holder  45  consists of a semi-circular recess  46  ( FIG. 6 ) forming a pair of outwardly extending arms  47  and  48  between which tube  21  may be positioned. A magnet  49  is mounted on the front surface  37  of the stove and is positioned to magnetically hold the metallic tube  21  in place. Alternatively, a magnet may be mounted to tube  21  to secure the tube to holder  45 . In such a case, magnet  49  is not necessary. 
     In order to position tube  21  to extend into the combustion chamber opening, tube  21  is grasped and pulled apart from holder  45 . The end of tube  21  is then inserted through recess  43  and into the opening  34  allowing gases within the tube to enter the combustion chamber. Suitable magnets  50  are provided on the front surface  37  of the stove main body immediately adjacent recess  43  to magnetically and removably hold tube  21  in recess  43 . 
     The external size of tube  21  is such that when installed within recess  43  it projects outwardly of the end or edge of wall  36 . For example, the radius of recess  43  may be approximately one-half the diameter of tube  21  if a cylindrical tube is utilized thereby providing for the remaining half of the tube to project outwardly from wall  36 . In such a case, stove door  30  will be prevented from closing in a completely sealed position relative to combustion chamber opening  34  creating a gap  51  that extends between the edge  52  ( FIG. 5 ) of wall  36  and the inwardly facing surface of door  30 . In order to limit air flow through gap  51 , a plurality of aluminum sheets are removably mounted to extend from wall  36  across gap  51  and the sides of door  30 . For example, a plurality of aluminum sheets  53  ( FIG. 5 ) are fashioned to fit externally around wall  36  being secured in place by magnets  54  attaching the sheets to the stove. The sheets then extend across gap  51  limiting the flow of air through the gap when the door has been moved to an intermediate position located between an open position depicted in  FIG. 3  and the completely closed position when the tube  21  is removed from recess  43 . Additional magnets may be used to secure aluminum strips  53  to sides  61  of the door. That is, magnets  54  may be used to secure strips  53  directly to the stove or directly to the door. Likewise, magnets  54  may be used to secure the metal strips  53  to both the stove and door with the object being to position and hold the metal strips across gap  51  when the door extends over opening  34  but spaced partially away from the stove main body forming gap  51  due to the presence of tube  21  in recess  43 . Strips  53  may be extended on the outwardly facing surface of portions  38 - 40  to thereby reduce the flow of air via gap  51 . 
     With valve  25  positioned to allow gas flow from tube  18  into conduit  20  and not conduit  24 , any radon within basement  13  is allowed to flow into perforated tube  19  and then into the combustion chamber of the stove when tube  21  is mounted to recess  43 . By turning on fan  27  forcing external air to flow into the basement via conduit  26 , the basement may be purged of radon gas. Tube  21  forms an air spout for collection of air including radon gas within the basement and directing same via opening  34  into the combustion chamber. 
     Combustion within the stove causes the gas within the combustion chamber to be hotter than gas within tubes  21 ,  20  and  19  thereby drawing up air and radon from the basement through tube  19  and eventually out of flue  17 . After valve  25  is closed to tube  20  and opened to tube  24 , spout  21  is removed from recess  43 , the draft is broken and radon will not flow up to stove  16 . No cap is needed to extend across recess  43 . Valve  25  is in a position blocking flow into conduit  20  while allowing gas flow from tube  18  to conduit  24 . 
     Many variations are contemplated and included in the present invention. For example, the drawing depicts a building have a basement; however, the radon collection system may also be used where the building does not have a basement. In such a case, the radon collection tube may be positioned beneath the slab supporting the building. 
     In order to continue to reduce radon within the building both when the stove is in a first condition heating the building and in a second condition not heating the building, there is disclosed herein a system that utilizes burning wood in the combustion chamber for heating the building and the gas within the chamber whereas only a lighted candle is placed in a combustion chamber so as to heat the gas within the chamber but not the building.  FIGS. 6 ,  7  and  8  disclose the same stove shown in  FIG. 2  with the burning wood  70  depicted in the combustion chamber in  FIG. 7  and the lighted candle  71  positioned within the combustion chamber in  FIG. 8 . Thus, the wood stove  16  has a main body  23  positioned atop a base spacing the main body of the stove above the floor. A combustion chamber  29  is formed within main body  23  with exhaust tube  17  leading therefrom. Door  30  is pivotally mounted by conventional hinges  31  and  32  to the front  33  of the stove. The door may be pivoted from an open position ( FIG. 2 ) to an intermediate position ( FIG. 4 ) to a completely closed position overlapping opening  34  leading into combustion chamber  29 . A radon collecting tube  21  is mounted to the stove as previously detailed herein and has a proximal end opening into chamber  29  and a distal end opening into the building such as depicted in  FIG. 1 . The radon collecting tube  21  is connected to a perforated tube  19  located in the basement of the building with a valve  25  operable to control the flow of gas within tube  19  to either the radon collecting tube  21  or an exhaust tube  24 , in turn, venting to the atmosphere. 
     A stack of burning wood  70  ( FIG. 7 ) is located within chamber  29  when the stove is in the first condition for heating the building and the gas located within the chamber thereby elevating the temperature of the gas within chamber  29  as compared to the lower temperature gas within radon collecting tube  21 . The resulting differential in temperature causes the radon gas within tube  21  to flow into chamber  29  and eventually exhausted via exhaust tube  17  leading from the combustion chamber to external of the building. 
     In  FIG. 8 , the burning wood has been replaced with a lighted candle  71  which barely generates enough heat to elevate the gas within chamber  29  when door  30  is closed resting against radon collecting tube  21  with the candle not being of sufficient size to generate heat to heat the building. For example, a typical candle of four to five inches in height and three inches in diameter will heat the gas within chamber  29  when the radon collecting tube  21  extends into opening  34  with door  30  resting against the radon collecting tube as illustrated in  FIG. 4 . On the other hand, a typical house, for example, of 1000 square feet or more, will not have the temperature of the air within the building raised by a single candle burning in the combustion chamber as compared to burning wood positioned within the chamber. On the other hand, the burning candle is adequate to elevate the temperature of the gas within the combustion chamber thereby drawing the relatively cooler radon gas in tube  21  into the chamber and then out exhaust vent  17 . 
     The radon collecting tube  21  extends from the basement as a single tube or a plurality of tubes such as shown in  FIG. 1 . Further, a fresh air conduit  26  leading from external of the building into the basement has a fan  27  ( FIG. 1 ) forcing outside fresh air through the conduit into the basement. As a result, as the air with radon is expelled from the building through exhaust tube  17 , external air flows into the building via conduit  26  eventually replacing all of the radon gas within the building with fresh air. 
     Radon collecting tube  21  is removably held by magnet  50  in recess  43  so as to open into opening  34  leading to the combustion chamber. In this position, door  30  may extend across opening  34 . The radon collecting tube when installed within recess  43  extends outwardly of wall  36 . As a result, door  30  contacts radon collecting tube  21  when the door extends across the opening creating gaps  51  between the door and edge  52  ( FIG. 5 ) of wall  36 . Aluminum sheets  53  ( FIG. 5 ) mounted to wall  36  and door  30  surround the combustion chamber opening limiting flow of air through the gaps between the door and wall  36 . 
     A series of measurements reflect the advantage of placing a lighted candle into the stove combustion chamber. For example, with wood burning in the stove and fan  27  on as shown in the drawings, the radon on the higher first floor of the building measured 5.0 picocuries per liter (pCi/L) while at the same time the radon in the lower basement was 5.4 pCi/L. When the stove is not burning wood, a lighted candle may be placed in the combustion chamber. Measurements were taken in such a case, i.e. the stove was not burning wood and having a lighted candle therein. In such a case, power to the building was turned off due to a storm thereby turning off fan  27  with the lighted candle within the chamber with the radon detected within the combustion chamber rising from 4.9 pCi/L to 9.0 pCi/L to 16.7 pCi/L to 18.4 pCi/L. At the moment the power was turned back on thereby operating fan  27 , the radon initially measured in the combustion chamber was 20.6 pCi/L while the radon in the basement measured 16.2 pCi/L. Over a period of time, with the candle in a lit condition in the combustion chamber and with fan  27  in operation, the radon in the combustion chamber rose from 20.6 pCi/L to 21.7 pCi/L to 21.8 pCi/L while at the same time the radon measured in the basement deceased from 16.2 pCi/L to 14.2 pCi/L to 12.6 pCi/L. With fan  27  in operation to bring fresh air into the basement, the radon in the basement decreased as the heat provided in the combustion chamber by the candle was operable to draw the radon up from the basement and into the combustion chamber. Thus, the radon in the combustion chamber decreased from 21.8 pCi/L to 21.3 pCi/L to 14.7 pCi/L to 6.8pCi/L as it rose up through the stove pipe and eventually stabilizing at 3.7 pCi/L. During the same period of time, the radon in the basement decreased from 12.6 pCi/L to 11.2 pCi/L to 8.1 pCi/L to 4.5 pCi/L and eventually stabilizing at 4.6 pCi/L. In other words, the radon levels in the combustion chamber having the lighted candle therein increased while the radon in the basement decreased until eventually the radon in the combustion chamber began to decrease over a period of time as less radon was available in the basement to withdraw into the combustion chamber. 
     The method of reducing radon in a building includes the step of first providing a stove having a combustion chamber for burning wood with a door movable over the opening of the chamber from a first position whereat the door uncovers the opening to a second positioning extending across the opening. A radon collecting tube opens into the chamber with the opposite end opening into the building. An exhaust tube leads from the chamber to external of the building to exhaust gas within the chamber. The door is moved to the open position with wood located within the chamber being lighted to heat the building and the gas within the chamber thereby drawing radon gas from the radon collecting tube into the chamber and eventually out through the exhaust tube. Immediately after the wood is lit, the door is moved to the position wherein the door extends across the chamber opening. Eventually, the wood is allowed to cool with the stove then being in a non-heating condition. The door may then be opened and a candle is placed into the combustion chamber assuming the chamber is cool and void of the burnable wood. The candle is then lit to heat the gas within the chamber causing sufficient heat in the chamber to draw radon gas from the tube into the chamber. The door is then moved to the position extending across the opening. 
     In one experiment, the candle having a diameter of three inches and being approximately four to five inches in height generated sufficient heat within the combustion chamber to cause the relatively cool radon gas within the radon collecting tube to flow into the combustion chamber while at the same time, the heat generated by the candle was sufficiently small so as to not heat the building and raise the building temperature. Fresh air is forced into the building to replace the gas flowing from the radon collecting tube into the combustion chamber and then out through the exhaust tube. The air may be forced into the building by use of fan  27 . 
     Stove  16  ( FIG. 2 ) includes a top  80  ( FIG. 9 ) with a cook top  81  covering a large opening in stove top  80  leading to the combustion chamber. The cook top  81  is pivotally mounted by a conventional fastener  85  in turn mounted to the top  80  of the stove. Cook top  81  can be lifted up and pivoted atop stove top  80  to the dashed line position  84 . The cook top may be made from cast iron. Removable plates  82  and  83  are mounted to cook top  81  and cover openings extending through cook top  81 . Plates  82  and  83  may be lifted in an upward direction separating from cook top  81  to determine if the candle  71  is lit and also allowing viewing of the condition of the candle as the candle burns. Normally, the candle is inserted into the stove in a lit condition through the front door of the stove although it is possible to insert the candle through an opening normally covered by one of the plates. Plates  82  and  83  may be mounted to cook top  81  in a variety of conventional ways, such as, providing a ledge within each opening upon which plates  82  and  83  may rest when inserted into the openings. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.