Heating liquid in portable tanks

Abstract

A heat exchanger apparatus for a portable tank that has an access opening and an access door removably attachable to seal the access opening. The apparatus includes a cover plate configured to be removably attached to the access opening to seal the access opening, and a heating circuit attached to an inner surface of the cover plate such that when the cover plate is attached to the access opening, the heating circuit extends into an interior of the tank. Input and output ports extend through the cover plate and are connected at inner ends thereof to the heating circuit such that fluid flowing into the input port flows through the heating circuit to the output port. The input and output ports are adapted at outer ends thereof for attachment to a fluid heating system to circulate heating fluid through the heating circuit.

What is claimed is: 
     
         1 . A heat exchanger apparatus for a portable tank, where the portable tank includes an access opening and an access door removably attachable to seal the access opening, the apparatus comprising:
 a cover plate configured to be removably attached to the access opening to seal the access opening;   a heating circuit attached to an inner surface of the cover plate such that when the cover plate is attached to the access opening, the heating circuit extends into an interior of the tank;   input and output ports extending through the cover plate and connected at inner ends thereof to the heating circuit such that fluid flowing into the input port flows through the heating circuit to the output port;   the input and output ports adapted at outer ends thereof for attachment to a fluid heating system to circulate heating fluid through the heating circuit.   
     
     
         2 . The apparatus of  claim 1  wherein the heating circuit comprises a heating conduit extending from the inner surface of the cover plate towards a far wall of the tank opposite the access opening. 
     
     
         3 . The apparatus of  claim 2  wherein the heating circuit comprises a plurality of loops of heating conduit extending back and forth between the far wall and the cover plate. 
     
     
         4 . The apparatus of  claim 3  wherein the heating conduit is provided by corrugated tubing. 
     
     
         5 . The apparatus of  claim 4  wherein the heating conduit is flexible, and comprising a brace member attached to the inner surface of the cover plate and extending toward the far wall, and wherein the heating conduit is supported on the brace member. 
     
     
         6 . The apparatus of  claim 5  comprising a support member mounted on a bottom inner portion of the brace member and adapted to move along a tank floor as the heating circuit moves into the interior of the tank during installation of the cover plate. 
     
     
         7 . The apparatus of  claim 5  wherein the brace member is made from aluminum. 
     
     
         8 . The apparatus of  claim 5  wherein the heating conduit is provided by corrugated stainless steel tubing with a wall thickness less than about 0.015 inches. 
     
     
         9 . The apparatus of  claim 7  wherein the heating conduit is provided a stainless steel portion of a flexible gas line, where the flexible gas line comprises the stainless steel portion covered by a coating. 
     
     
         10 . The apparatus of  claim 4  wherein the heating conduit is substantially rigid. 
     
     
         11 . The apparatus of  claim 10  comprising a support member mounted on a bottom inner portion of the rigid heating conduit and configured to move along a tank floor as the heating circuit moves into the interior of the tank during installation of the cover plate. 
     
     
         12 . The apparatus of  claim 1  wherein the cover plate is made from aluminum. 
     
     
         13 . A method of heating a target liquid in a portable tank, where the portable tank includes an access opening and an access door removably attachable to seal the access opening, the method comprising:
 configuring a cover plate to be removably attached to the access opening to seal the access opening;   attaching a heating circuit to an inner surface of the cover plate such that when the cover plate is attached to the access opening, the heating circuit extends into an interior of the tank;   extending input and output ports through the cover plate and connecting inner ends thereof to the heating circuit;   installing the tank at a desired location;   attaching the cover plate to the access opening such that the heating circuit extends into the interior of the tank, and such that the access opening is sealed;   filling the tank with the target liquid to a level above the heating circuit;   attaching outer ends of the input and output ports to a fluid heating system and circulating heating fluid through the heating circuit.   
     
     
         14 . The method of  claim 13  comprising, when it is desired to move the tank to a different location, removing the target liquid from the tank; removing the cover plate from the access opening and removing the heating circuit from the interior of the tank; loading the tank and the cover plate with the heating circuit on one or more vehicles for transport. 
     
     
         15 . The method of  claim 13  wherein the heating circuit comprises a heating conduit extending from the inner surface of the cover plate towards a far wall of the tank opposite the access opening. 
     
     
         16 . The method of  claim 15  wherein the heating circuit comprises a plurality of loops of heating conduit extending back and forth between the far wall and the cover plate. 
     
     
         17 . The method of  claim 16  wherein the heating conduit is provided by corrugated tubing. 
     
     
         18 . The method of  claim 17  wherein the heating conduit is flexible, and comprising a brace member attached to the inner surface of the cover plate and extending toward the far wall, and wherein the heating conduit is supported on the brace member. 
     
     
         19 . The method of  claim 18  comprising mounting a support member on a bottom inner portion of the brace member and resting the support member on a tank floor as the heating circuit moves into the interior of the tank during installation of the cover plate. 
     
     
         20 . The method of  claim 16  wherein the heating conduit is substantially rigid.