Patent Publication Number: US-9403538-B2

Title: Efficient sand tub heater

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 61/684,012, filed Aug. 16, 2012 and entitled “Efficient Sand Tube Heater”. The aforementioned application is incorporated by reference in its entirety herein. 
    
    
     BACKGROUND 
     Sand tubes are used to increase the amount of friction between a railroad track and the wheel of a train. Sand tubes are located at the front of a wheel and disperse sand along the track to allow greater friction during cold and icy weather between the wheel of the train and track. Sand tubes without heating systems require manually hitting the sand tube to break up the ice inside the tube. This can cause severe damage to the sand tube rendering the sand tube inoperable. United States Federal Regulations require that all trains to have sand tubes operable at all times and there is a significant fine if the tubes are frozen when inspected. 
     Typical prior art such as that shown in U.S. Pat. No. 1,528,552 implement heating systems for keeping the sand inside the sand tubes above freezing temperature to ensure that the sand is not frozen during operation. The prior art disclosed in U.S. Pat. No. 1,528,552 implements an electrical heated medium coiled around the lower portion of the sand tube. The electrical heated medium is then encased in a structure. The structure is then filled with a loose fire retardant material such as asbestos. 
     The prior art in U.S. Pat. No. 1,528,552 has disadvantages and difficulties in implementing an efficient and properly functioning sand tube. The heating element is not in constant connection to the sand tube, therefore does not efficiently heat the sand inside of the tube. Additionally, the structure surrounding the heating element is difficult to maintain when repairs are needed. 
     Another such prior art reference U.S. Pat. No. 2,654,622 discloses a heating system which uses hot liquid traveling through coils wrapped around the sand tube and forced air provided by the locomotive to keep the sand from freezing and to keep the sand dispensing tube freely operable. This invention has difficulties and disadvantages in that the heating coils do not rise to a sufficient heat temperature to keep the sand from freezing during very low temperatures. Therefore, even with such methods of heating the sand, the sand tube can still freeze where the hot water inside the coils does not sufficiently heat the sand inside of the tube. 
     Other methods of heating the sand inside the tube include using engine exhaust, heat provided off of the engine, or other circulated heated liquids. However, these methods fail to properly heat the sand to an adequate temperature during extreme cold. 
     SUMMARY 
     In accordance with one embodiment, a system for heating and dispersing sand in front of a vehicle&#39;s wheels including a sand tube, a flexible heating element coiled around the sand tube, a heat sensitive sheathing wrapped around the sand tube and flexible heating element, and an electrical thermostat controller coupled to the electrical heating element. The heat sensitive sheathing is shrunk around the electrical heating element and sand tube to insure constant contact between the sand tube and electrical heating element. The thermostat controller is controlled by an operator to vary the amount of heat produced by the electrical heating element. 
     In accordance with one embodiment, a method for heating and dispersing sand in front of a vehicle&#39;s wheels including wrapping a flexible electrical heating element around a tube for holding and dispersing sand; wrapping a heat sensitive sheathing around the tube and flexible electrical heating element; applying heat to the heat sensitive sheathing to compact the flexible electrical heating element so that it is in constant contact with the tube. The electrical heating element is then coupled to a thermostat controller to allow exact control of the heat provided by the electrical heating element. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows an exemplary heated sand tube system. 
         FIG. 2  shows a cross sectional view of an exemplary heated sand tube system. 
         FIG. 3  shows an exemplary implementation of a heated sand tube system. 
         FIG. 4  depicts a method for manufacturing an efficient sand tube heater, in one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  shows one exemplary sand tube system  100  for dispersing sand for use in a vehicle. The sand tube  102  is for example sized and shaped to fit onto a locomotive train. Although not illustrated, sand tube  102  may further have a valve at the distal end such to control distribution of the sand. The sand tube  102  is then wrapped with a flexible electrical heating element  104 . In one embodiment, electrical heating element  104  may reach temperatures up to 400 degrees Fahrenheit. For example, electrical heating element  104  can be realized, by using an Asr Duo-Tape® as manufactured by HTS/Amptek Company. Electrical heating element  104  is then coupled to a thermostat controller  106  to produce temperatures of up to 400 degrees Fahrenheit. The thermostat controller  106  is capable of allowing an exact control of temperature. The thermostat controller  106  may be realized, in one embodiment, using a TX Series CE 0081 thermostat controller available from Barksdale, Inc. The sand tube  102  and electrical heating element  104  are then wrapped with a heat sensitive sheathing  108 . Heat is then applied to the heat sensitive sheathing  108  which causes the heat sensitive sheathing  108  to shrink around the electrical heating element  104  and sand tube  102 . As the heat sensitive sheathing  108  shrinks, the sheathing causes the electrical heating element  104  to come into direct contact with the sand tube  102  ensuring an efficient conduction of heat from the heating element  104  to the sand tube  102 . The heat sensitive sheathing  108  is also made of sufficient durability and thickness to protect the electrical heating element  104  from damage during operation of the locomotive. 
       FIG. 2  shows an exemplary cross sectional view  200  of the sand tube system  100  after heat is applied to the heat sensitive sheathing  108 . As shown in  FIG. 2 , the heat sensitive sheathing  108  fully surrounds the electrical heating element  104  and sand tube  102 . Additionally, the electrical heating element  104  is in direct contact with sand tube  102 . 
       FIG. 3  shows exemplary implementation of sand tube system  100  as used in conjunction with a locomotive  300 . Sand tube system  100  is mounted in front of the locomotive wheel  302 . Multiple sand tube systems  100  may be implemented on the locomotive  300  in front of each wheel  302 ( 1 ) and  302 ( 2 ). Thermostat controller  106  may be coupled to electrical heating element  102  in such a way that the thermostat controller  106  is located in the cab of the locomotive to allow the operator of the locomotive to exactly control the temperature of the electrical heating element  102  without leaving the cab. Sand tube system  100  insures that the sand inside sand tube  102  is not frozen and can be applied to track  304  while the locomotive  300  is in use thus properly keeping the sand tube in compliance with federal regulations. 
       FIG. 4  depicts an exemplary method  400  for manufacturing an efficient sand tube heater, in one embodiment. 
     In step  402 , a sand tube is wrapped with a flexible electrical heating element. For example, flexible heating element  104  is wrapped around sand tube  102 , of  FIGS. 1-3 . In one embodiment, flexible heating element is closely wrapped such that substantially the entire outer surface of the sand tube is covered by flexible heating element. In another embodiment, the flexible heating element is wrapped such that there are gaps between each wrapped portion of the heating element (i.e. as illustrated in  FIG. 1 ). 
     In step  404 , sand tube and surrounding flexible heating element of step  402  is surrounded with a heat sensitive sheathing. For example, flexible heating element  104  wrapped around sand tube  102  is surrounded with heat sensitive sheathing  108 , of  FIGS. 1-2 . 
     In step  406 , heat is applied to the heat sensitive sheathing such that the heat sensitive sheathing shrinks around the flexible heating element and sand tube. This causes the flexible heating element to tightly wrap around the sand tube such that the flexible heating element remains in constant contact with the sand tube. For example, heat is applied to heat sensitive sheathing  108  such that flexible heating element  104  remains in contact with sand tube  102  as illustrated in  FIG. 1 . 
     In optional step  408 , the flexible heating element is coupled to a thermostat controller. For example, flexible heating element  104  is coupled to electrical thermostat controller  106  as illustrated in  FIG. 1 . Further, in one embodiment, electrical thermostat controller  106  is located within the operator cab of a locomotive as illustrated in  FIG. 3 . 
     Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween.