Abstract:
Heating systems and methods of preventing freeze-ups of underground tank systems. In septic underground tank systems, bacteria activity is enhanced by raising the temperature within the bacteria&#39;s environment. The preferred heater system includes a thermostatic control unit with a temperature sensor which may be selectively located to sense the temperature within a portion of the underground tank system. The heating systems and methods are particularly useful in mound or drainfield septic systems as well as underground water tanks.

Description:
BACKGROUND OF THE DISCLOSURE 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to heating systems. Particularly, the present invention relates to heating systems for the prevention of underground tank system freeze-ups and to enhance bacterial activity in septic system tanks. More particularly, the present invention relates to a heating system having a thermostatic control unit which may be selectively located to sense the temperature within a portion of an underground tank system containing a fluid subject to freeze-up. 
         [0003]    2. Description of the Related Art 
         [0004]    Previously, it was common to bury septic tanks deep in the ground. Due to current government regulations, septic tanks are now often installed very shallow. This is to help limit the amount of sewage that seeps into the water supply. In many areas, during cold winter months, frost penetrates several feet into the ground. This makes septic systems buried shallow in the ground very vulnerable to freezing, especially septic systems that are not used daily. 
         [0005]    Freezing can occur anywhere within a septic system. Particularly, if there is a sag in the pipe, the sag is often the cause as the standing water freezes and then builds as water trickles past until the pipe is completely blocked. When a septic system freezes, the flow of effluent from the septic tank is obstructed, causing the septic system to back up and become inoperative. Additionally, freezing or near freezing septic tanks have significantly reduced bacterial activity. Decreased bacterial activity results in a slowing of the natural decomposition of organic solids in the tank. 
         [0006]    Another common area of freeze-up is where the sewage enters the drainfield, at which point the pipe connects to a drop box. The drop box is usually less than 3 feet underground and always has water in it. This area will freeze when surrounded by frozen ground. When the drop box water freezes, ice builds up as water trickles from the septic tank, eventually blocking the pipe. 
         [0007]    In traditional mound systems or systems with lift stations, which utilize a pump to force sewage under pressure into an elevated, earthen mound, freezing can occur between the house and the tank, within the tank or lift station itself, after the lift station, and/or in the mound. The most common area where freezing occurs is the lift station and the discharge pipe that leads from the lift station pump to the mound. If the pipe that goes to the mound freezes, it is often because the weep hole in the pipe has frozen shut, preventing the residual water from draining back into the lift station. 
         [0008]    There are generally two known ways to remedy a frozen septic system, both of which are costly, time consuming and inconvenient. The first remedy is to have a plumber jet or steam the underground pipes, usually a few times during the cold spell. This is an effective way to unclog the pipes, but there are risks of overstressing the pipe and joints. The amount of pressure and heat used in this method can exceed 2000 psi and 500° F. Sewer pipe is typically not designed to sustain such extreme temperature. This remedy usually requires multiple service calls because the pipe eventually refreezes since nothing is done to prevent future freezing. 
         [0009]    The second remedy is to have your tank pumped regularly while your pipes are clogged and allow the ground to thaw at its natural pace. This method is inconvenient, unpredictable and requires careful restricted use of water to minimize the risk of pipes backing up sewage into the home. 
         [0010]    To address freeze-ups in septic systems, heated systems for the prevention of freeze-ups have been devised. One such system is taught in U.S. Pat. No. 6,869,533 (2005, Norgaard). This known system includes a heater, fan and thermostat in an enclosure located above ground that is interconnected with a cleanout pipe of a traditional drainfield system. The thermostat measures the outdoor temperature such that the heater will be activated when the outdoor temperature reaches a predetermined level in which the septic fluid would be likely to freeze. Hot air is then transferred from the heater to the respective cleanout pipe and circulated through the drop box and into a drainfield. 
         [0011]    In some areas having particularly rocky soil making it difficult to install drop box manifolds and sewage distribution pipes in a drainfield at acceptable depths underground, mound type septic systems are utilized. Such systems are provided with an earthen mound above normal ground level which serves as a drainfield into which sewage from a septic tank is direct by a lift pump. Mound systems are also subject to freeze-ups particularly in the pump housing and the pump discharge pipe as the mound systems are not insulated by a substantial amount of earthen material. 
         [0012]    There are additional types of underground liquid storage tanks that are susceptible to freeze ups. One such type of underground liquid storage tank is an underground water storage tank commonly used, for example, in Canada and Alaska. In these areas, the rocky earth generally makes drilling wells very difficult and the quality of the ground water is often poor such that alternative water sources are desired. Known underground water storage tanks typically include a tank enclosure interconnected to at least two access pipes accessible from above ground. Underground, a water line interconnects the tank enclosure to the house or other building. Just as with the known septic systems mentioned above, these known water tanks can freeze up in cold winter months resulting in inaccessibility to water and/or water line breakage. 
         [0013]    The present invention provides improvements that solve problems with the related art. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention relates to heating systems and thermostatic control units for underground tank systems such as septic systems, water tanks and the like that prevents freezing of fluids located within the system. The heater system is used in conjunction with an underground tank system including a tank enclosure and a pipe connecting the tank enclosure to an access point above ground level. The tank enclosure can be a septic tank, water tank or the like. In preferred embodiments, the heater assembly is adapted for fluid flow connection to the access pipe for easy installation and maintenance. The preferred heater system includes a heater assembly having a heating element for producing hot air and a blower assembly positioned and arranged to direct air in heat exchange relation to the heater assembly and to distribute the hot air. The preferred heater assembly further includes a thermostatic control unit for actuating the heating element. In the most preferred embodiments, the thermostatic control unit has a remotely locatable temperature sensor to sense the temperature within a component of the underground tank system, such as the tank enclosure or cleanout/access pipe, by being located within the component of the underground tank system. The temperature sensor is preferably placed proximate where freeze-ups could occur such that the temperature reading is more accurate and can better predict when heating is required. 
         [0015]    These and various other advantages and features of novelty which characterize the present invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    In the drawings, in which corresponding reference numerals and letters indicate corresponding parts of the various embodiments throughout the several views, and in which the various embodiments generally differ only in the manner described and/or shown, but otherwise include corresponding parts; 
           [0017]      FIG. 1  is schematic view of a septic tank system  10  having a septic tank  16 , a plurality of cleanout pipes  22  and a drainfield treatment area  18 ; 
           [0018]      FIG. 2  is a schematic view of a mound septic tank system  10 ′ having a septic tank  16 , a lift station  26 , a plurality of cleanout pipes  22  and a mound system treatment area  24 ; 
           [0019]      FIG. 3  is a partial, cutaway view of a septic tank heater  12  of the present invention used in conjunction with the underground tank systems shown and described (only one cleanout pipe  22  is shown for clarity); 
           [0020]      FIG. 4  is a partial, cutaway view of the septic tank heater  12  of  FIGS. 1-3 ; 
           [0021]      FIG. 5  is an enlarged view of the lift station  26  of  FIG. 2 ; and 
           [0022]      FIG. 6  is a schematic view of a water storage tank  54  embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]      FIG. 1  is a schematic view of a gravity flow septic system  10  incorporating an embodiment of an underground tank heater system  12  of the present invention (the heater system  12  is shown enlarged for clarity). As shown in  FIG. 1 , the septic system  10  includes a sewer pipe  14 A that extends from a house H to a tank enclosure  16  and then on via a sewer pipe  14 B to a treatment area  18 . In  FIG. 1 , the treatment area  18  is a drainfield and includes a series of drop boxes  20 . As shown, the drop boxes  20  are connected to one another for further distribution of the effluent sewage (not shown). Each drop box  20  typically has a respective cleanout or access pipe  22  to an access port  23  at an above ground level G location. At the house end of the sewer pipe  14 A, the sewer pipe  14 A is connected by way of a soil stack  19  to a vent  20  that typically protrudes from the roof R of the house H. The septic system  10  further includes additional cleanout pipes  22  that run up to or above ground level G from the septic system  10 , for example, from any one or a combination of the septic tank  16 , the sewer pipes  14 A-B, and the drop boxes  20 . 
         [0024]    As  FIG. 2  illustrates, the present invention can be used in septic systems  10 ′ of the mound type having a treatment area  18 ′ within a raised mound system  21 . Mound systems are positioned above ground level G and will generally require lift stations  26  to transport the effluent sewage (not shown) against gravitational forces to a sewage distribution header  24  positioned in the mound  21 . As shown, the lift station  26  can be aligned in parallel connection with the septic tank  16  with a connection pipe  14 C. Alternatively, the lift station  26  can be located within the septic tank  16 . Now also referring to  FIG. 5 , the lift station  26  includes a pump  28  for moving sewage effluent (not shown) upwards towards the mound system treatment area  18 ′. The preferred lift station  26  includes a pump housing  30  and pipe connections  32  made of PVC or the like. One of the pipe connections  32  extends out from the lift station  26  and is connected to discharge pipe  14 B leading to distribution header  24  in the mound  21 . In preferred embodiments, pump  28  transfers the sewage effluent (not shown) from the lift station  26 , through the pipe  32  and  14 B to the mound system for distribution into the treatment area  18 ′. The preferred pump  28  is submersible and includes a liquid level sensor  36 , float switch or the like to activate the pump  28  when the sewage fluid in the lift pump housing  26  reaches a predetermined level. 
         [0025]    Mound systems are particularly useful in areas where the earth is very rocky and it is difficult to dig deep enough for installing a drainfield. Often, in these areas, the climate is also very cold and the septic systems are prone to freezing in the winter months. To prevent freeze-ups in both ordinary drainfield systems and mound systems, the septic systems  10 ,  10 ′ of the present invention preferably include at least one heater system  12 . As best illustrated in  FIG. 4 , the heater system  12  includes a heating element  40 , preferably an electric coil, located within a casing  42  that at least partially encloses the heater element  40 . An outer housing  41  encloses the heating components, including casing  42 , and is arranged and configured at its bottom end  41 A to form a coupling defining an output port such that the heater assembly can be mounted in a slip fit over the cleanout pipe  22 . The heater system  12  further includes a blower assembly  46  having a motor  46 A driving blower  46 B located above the heating element  40  within housing  41  for directing and circulating warm or hot air down into the septic system  10 ,  10 ′ through the respective access or cleanout pipe  22 . For that purpose an air intake pipe  43  is connected to housing  41  above blower  46 B and is provided with an air intake  43 A. 
         [0026]    The heater assembly  12  further includes a thermostatic control unit  48  to activate the electric heater element  40  and blower motor  46 A. A removable cover  48 A on control unit  48  permits access to the wiring and controls for blower motor  46 A and heating element  40 . A temperature controller (not shown) is housed within the control unit  48 , and may be adjusted to the desired temperature to be maintained within the septic system so as to prevent freeze-ups. The temperature controller preferably includes a sensor  50  that is located within the respective access/cleanout pipe  22 , the septic tank  16  or the lift station  26 , depending on which component of the septic system  10 ,  10 ′ is at risk for freeze-ups. The sensor  50  is preferably attached to a cable or lead wire  52  coupled to the temperature controller and is set to activate the heater system  12  at a predetermined, low temperature that could otherwise cause the septic system  10 ,  10 ′ to undergo freeze-up. That temperature is preferably on the order of 38 degrees F. The heater system may be set to operate for an extended time period, e.g., for as long as two hours, after activation, or to shut-off when a predetermined high temperature has been reached. If the heater assembly operates for a long as two hours, the temperature of the air above the liquid in the tank may rise to above 100 degrees F. In preferred embodiments, the position of the sensor  50  within the septic system can be adjusted, for example, by either lengthening or shortening (raising or lowering) the cable  52 . 
         [0027]    The temperature sensor  50  may be placed within the interior of the septic tank  16  ( FIG. 3 ), inside the lift pump housing  26  ( FIG. 5 ), or within an access pipe  22 . In either sensing position, the actual temperature within the septic system is sensed and controlled. Providing a heater and methods that utilize a thermostatic control unit  48  in such a way as to sense and regulate the temperatue inside the septic system provides for a more accurate reading of the temperature of the septic system, which better predicts freezing conditions and more efficiently controls the heater system. 
         [0028]    The thermostatic control unit  48  may further include a temperature sensor  49  located near the hot air output end of housing  41  by output coupling  41 A. Operation of the heater  40  and blower assembly  46  may be further regulated by the sensor  49  to achieve the desired temperature of warm air discharged through output coupling  41 A. 
         [0029]    A particular benefit realized by the disclosed heating system is increased bacterial activity in the sewage being handled. Bacteria thrive in a warm environment. Heating the sewage to a temperature above 38 degrees F. greatly enchases bacterial formation and activity. Breakdown of the sewage by bacteria is thus significantly improved. 
         [0030]    It will be clear to one of ordinary skill in the art, in light of this disclosure, that the heater system  12  of the present invention will prove useful and effective in many various underground tank systems. Another such underground tank system is illustrated in  FIG. 6 .  FIG. 6  illustrates a water storage tank  54  buried under the ground level G. The water storage tank  54  shown includes a tank enclosure  56  having a fill pipe  58  and a vent pipe  60  leading above the ground level G. The water storage tank  54  further includes a water line or pipe  62  interconnecting the tank enclosure  56  to a house (not shown). The heater assembly  12  of the present invention can be mounted to the fill pipe  58  similarly to how the heater assembly is attached to a cleanout/access pipe as discussed above. The slip fit of heater assembly coupling  41 A over fill pipe  58  permits easy mounting and removal of the heater assembly  12 . Access to fill pipe  58  to refill tank  54  can thus be readily obtained. The temperature sensor  50  is preferably positioned within the tank enclosure  56  to accurately measure the temperature within the tank enclosure  56 . When the heater system  12  is heating the water storage tank  54 , heat produced from the heater system  12  flows down through the fill pipe  58 , into the tank enclosure  56  and vents through the vent pipe  60 . Such heater systems and methods of heating a water tank prevent freeze ups, thus maintaining the water supply and eliminating the associated costs with thawing a freeze-up. 
         [0031]    Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.