Abstract:
A method and apparatus for preventing a dense liquid such as diesel fuel from being dispensed into a storage tank that contains a less dense liquid, such as gasoline fuel and vice versa. The unloading process happens by gravity through a vertical down hole. The invention uses the gravitational flow of the fluid, a movable float that is moved by contact with a fluid of a predetermined density, and a magnetic member to activate the stopping feature.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention (Technical Field) 
   The present invention relates to fuel distribution and more particularly to a method and apparatus that prevents a wrong fuel product being dispensed into a storage tank. 
   2. Background Art 
   Presently there is a need for an apparatus or method to keep fuel tanker drivers from delivering the wrong fuel to a storage tank. Storage tanks are located in gas stations, truck stops, pipeline terminals, and refineries. Most storage tanks are underground, so it is impossible to visually determine what type of fuel the storage tank contains. Today most storage tanks are marked or color coded to alert the delivery person as to what type of fuel is contained within the tanks; however wrong deliveries still occur. In addition, delivery tankers have several compartments separated from each other to make it possible to transport different kinds of fuels at the same time such as gasoline and diesel. Due to the inattention of the driver, sometimes the driver unloads the wrong product into the wrong storage tank. When this happens, the intermixed fuel cannot be used because it will cause significant damage to any vehicle using the intermixed fuel. The same disastrous results occur with the use of the wrong fuel in a vehicle. In addition, an apparatus and/or method to prevent a wrong type of fuel from being dispensed from a holding tank to a vehicle tank are also necessary and can be accomplished with the present invention. 
   Several attempts have been made to solve a similar problem; however they are very complicated, costly, and require a separate power source for use. One of these prior art devices is discussed in U.S. Pat. No. 4,537,232. This device teaches an apparatus and method to disrupt the flow of the fluid upon detection of a nonconforming liquid. The device shuts down an electric pump, thus preventing the fluid from flowing. The device could not be used in an underground tank or down a filler hole and function completely on its own due to its size. The device needs electric wiring and power. It is designed to work on liquids that are pumped and are traveling upwards. Furthermore, it uses a two-step process; it shuts down a pump with an actuator, which in turn stops the flow. The device does not use the natural flow of the liquid to activate the flow-stopping feature. 
   Other prior art devices are disclosed in U.S. Pat. Nos. 4,632,139 and 4,865,070. Each of these devices separates liquids that are already mixed; they do not prevent mixing of unlike liquids. Further, they only work with liquids that do not mix with each other. The floating element in these devices is the actual stopper of the fluid and is not used to stop the flow of the wrong liquid down a filler tube or hole. 
   Other prior art devices use a floating device that sinks in a light liquid and floats in a dense liquid. The device is described in U.S. Pat. No. 4,537,232. However, as with other prior art devises, the stopping feature operates in one mode. For instance, they will only prevent a less dense fluid from flowing, but do not operate in a second mode; preventing a more dense fluid from flowing. The present invention operates in both modes. The floating device carries a prism to direct light to a photo electric cell or a magnet to disrupt electric power to stop a pump. 
   The present invention is a unique apparatus that prevents a wrong fluid from flowing, because fuels like gasoline and diesel mix very easily. The invention uses a one step process with no extraneous devices. It uses gravity to operate. The invention operates completely in a filler tube or down hole. It does not need electrical power, and it prevents the mixing of liquids that mix with each other. The invention activates a stopper that shuts down the flow of a liquid that flows by gravity. 
   SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION) 
   Delivering and unloading a wrong fuel product to a gas station or truck stop is not a common mistake, but when it happens it is very costly. To install a transmix prevention lock (TPL) in a fuel storage tank would eliminate this problem. The apparatus fits down a filler tube or down hole, stops the flow of a wrong fluid from flowing, and allows a right type of fluid to flow. The invention uses the gravitational flow of the fluid, a movable float that is moved by contact with a fluid of a predetermined density and magnetic member to activate the stopping feature. The present invention is easy to install and reset without causing any type of safety hazard. Once installed it does not need to be changed and requires minimal maintenance. The invention can also be used in cars, trucks or any gasoline or diesel powered equipment to prevent pumping the wrong fuel into the fuel tank. 
   A primary object of the present invention is to provide a method and apparatus to prevent a wrong fluid from flowing into a container. 
   Another object of the present invention is to provide a fail-safe method and apparatus that is self contained and does not require a power source. 
   Yet another object of the present invention is to provide a TPL that activates in a very short period of time. 
   A primary advantage of the present invention is its simplicity to manufacture and use. 
   Another advantage of the present invention is that it is inexpensive to manufacture. 
   Yet another advantage of the present invention is that it is easy to install and reset. 
   Other objects, advantages, and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings: 
       FIG. 1  shows the preferred embodiment of the invention in an open or flowing position. 
       FIG. 2  shows the embodiment of  FIG. 1  in a closed or non-flowing position. 
       FIG. 3  is an alternative embodiment of the invention in an open or flowing position 
       FIG. 4  shows the embodiment of  FIG. 3  in a closed or non-flowing position. 
       FIG. 5  shows an alternative embodiment for the activation mechanism. 
       FIG. 6  shows an alternative embodiment for the fluid injectors of  FIGS. 3 and 4 . 
       FIG. 7  is a top view of the embodiment of  FIG. 1 . 
       FIG. 8  is a top view of the embodiment of  FIG. 3 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Best Modes for Carrying out the Invention 
     FIGS. 1 and 2  show the first embodiment of the invention. This embodiment is used to activate the flow stopping action if a denser fluid is added. For example, if the tank is required to have gasoline and diesel is introduced, the invention is used to prevent the diesel from entering the tank.  FIG. 1  shows the apparatus in a flowing or non-activated state and  FIG. 2  shows the apparatus obstructing the flow or activated state. TPL  100  is placed inside of a down hole or filler tube  118  of a storage tank. TPL  100  is held in position by supporting bracket  102  that holds activation tube  104  substantially in the middle of filler tube  118 . Although the embodiment of  FIGS. 1 and 2  show a supporting bracket  102  consisting of a collar wedged onto a flange of filler tube  118 , different affixing devices that are well known in the art can be used. The illustration is not meant to limit this feature. Activation tube  104  has an open end  124  for receiving the fluid and a closed bottom end  126  for containing the introduced fluid. Attached to the bottom of activation tube  104  is shaft  114  with spring-loaded stopper  116 .  FIG. 1  shows spring-loaded stopper  116  in a liquid flowing or folded position. Inside activation tube  104  is floating structure  112  that floats in a first liquid type and sinks in a second liquid type. For example, a floating structure that floats in diesel but sinks in gasoline. Floating structure  112  is smaller in diameter than activation tube  104  so it can move freely up or down inside activation tube  104 . In the flowing or non-activated state, floating structure  112  sits on closed bottom end  126  of activation tube  104 . A first magnetic member  110  is affixed to upper end  128  of floating structure  112 . A second magnetic member  106  is affixed inside the top part of activation tube  104  at a predetermined distance from first magnetic member  110  to prevent the magnetic attraction from each other in the flowing mode. A first end of unlocking pin  108  is positioned between magnetic members  106  and  110 , and a second end of unlocking pin  108  exits from closed bottom end  126  of activation tube  104  through a small exit aperture  122  and into release mechanism  130  which holds stopper  116  in a folded position. 
   In operation, the delivery person places TPL  100  into filler tube  118 , as shown. When gasoline is introduced into filler tube  118 , activation tube  104  fills with gasoline and floating structure  112  stays on bottom end  126  of activation tube  104  since it is heavier than gasoline. If diesel fuel is introduced into filler tube  118 , activation tube  104  fills with diesel and since floating structure  112  is lighter than diesel, it floats and moves upwards. This in turn, moves first magnetic member  110  towards second magnetic member  106 . Floating structure  112  with affixed first magnetic member  110  contacts unlocking pin  108 . At a predetermined point, the magnetic attraction from the two magnetic members  106  and  110  is provided. The magnetic attraction and the force of the floating structure  112  causes unlocking pin  108  to move upward, activating release mechanism  130  which opens stopper  116  and stops the flow of the diesel fuel as shown in  FIG. 2 . To reset TPL  100 , the delivery person has to close the unloading valve on the tanker truck, empty the hose and unhook it from filler tube  118 . He lifts TPL  100  out of the filler tube  118 , separates second magnetic member  106  from first magnetic member  110  by pulling unlocking pin  108  downwards or out of activation tube  104  until the floating structure  112  falls back to closed bottom end  126  of the activation tube  104 , then he folds stopper  116  and secures it with unlocking pin  108 . He can then set TPL  100  back into filler tube  118  and continue filling the tank with the correct fuel. 
   A second embodiment of the present invention is shown in  FIGS. 3 and 4 . This embodiment is for the opposite uses of  FIGS. 1 and 2 . This embodiment is for stopping a less dense fluid from flowing. For example, if the tank contains diesel, this embodiment prevents gasoline from being introduced into the tank. As with the first embodiment, TPL  200  is affixed in filler tube  218  with supporting bracket  202  for holding activation tube  204  substantially in the middle of filler tube  218 . Activation tube  204  has an open end  232  for receiving the liquid and closed bottom end  234 . As shown, activation tube  204  has a separating wall  224  and forming chambers  228  and  230 . Separating wall  224  is provided to keep floating structure  212  from sinking too far and to permit magnet  210  to move upwards. The lower part of activation tube  204  can be threaded  236  to accommodate second and shorter tube  238 . Activation tube  204  comprises long chamber  230 , and second or shorter tube  238  comprises a lower and shorter chamber  228 . Contained within lower chamber  228  is first magnetic member  210  which is connected to unlocking pin  208 . First magnetic member  210  is smaller in diameter than the inside diameter of lower chamber  228  so first magnetic member  210  with unlocking pin  208  can move freely up or down. Spring-loaded stopper  216  is attached to the lower part of the lower chamber  228 . One end of the unlocking pin  208  exits lower chamber  228  through small exit aperture  222  and keeps spring-loaded stopper  216  in a folded position. Inside top chamber  230  is a floating structure  212  with a second magnetic member  206  mounted on its lower part. Floating structure  212  can move freely up or down within top chamber  230 . When TPL  200  is being placed into the filler tube  218 , activation tube  204  is filled with diesel fuel, which makes floating structure  212  float inside of the activation tube  204 . A top wall  226  is provided to restrain the floating structure  212  at a desired height when it is in floating position. In addition liquid injector  242  is provided to introduce the liquid inside activation tube  204  and maintain top wall  226 . This allows the fluid or diesel fuel in this case to flow into filler tube  218  and fill the storage tank. 
   If gasoline is introduced into filler tube  218  and also activation tube  204  the gasoline will mix with the diesel or fill the inside of the activation tube  204 , thus changing the density of the liquid inside activation tube  204 , causing floating structure  212  to sink to the bottom of activation tube  204 . When floating structure  212  reaches a predetermined distance close to the bottom of activation tube  204 , second magnetic member  206  will pull up or attract first magnetic member  210  in lower chamber  228 . Since unlocking pin  208  is attached to first magnetic member  2110 , as first magnetic member  210  moves upwards, it will pull up unlocking pin  208 , activating release mechanism  240 , causing spring-loaded stopper  216  to open and in turn shuts down the flow of gasoline. To reset TPL  200  the operator has to close the unloading valve on the tanker, empty the hose and remove TPL  200  from filler tube  218  empty the fluid from activation tube  204  and unscrew bottom chamber  228  from the top chamber  230 . The operator separates second magnetic member  206  from first magnetic member  210 , fills up activation tube  204  with diesel which makes floating structure  212  float. Then he folds stopper  216  and secures it with unlocking pin  208  and then reattaches shorter tube  238  and TPL  200  is ready for another filling operation. 
   Supporting brackets  102  and  202  are configured to hold and keep activation tubes  104  and  204  in place. Although the figures show specific embodiments, supporting brackets  102  and  202  can vary in size, shape or form as long they are strong enough and allow the fuel to flow freely into filler tube  118  and  218  and into activation tubes  104  and  204 . The preferred activation tubes  104  and  204  are constructed from a non-magnetic material. Small exit aperture  122  and  222  is preferably bigger in diameter than the unlocking pin  108  and  208 , to allow movement of unlocking pin  108  and  208  and also to allow liquid to drain out of activation tube  104 . Small exit aperture  122  cannot be big enough to create a suction force by the draining fluid since that would affect the floating ability of floating structures  112 . On the upper part of tubes  104  and  204  are air or diesel release apertures  120  and  220 . When the flowing liquid is introduced into tube  104  and  204 , the displaced air or diesel exits through the air or diesel release apertures  120  and  220 . 
   Floating structures  112  and  212  are selected from a specific material that is calibrated to float in a first type of fluid and to sink in a second type of fluid. For example, in the embodiments as described above, a material is selected that floats in diesel fuel and sinks in gasoline. Magnetic members  106 ,  110 ,  206 , and  210  can be any type of magnetic material with sufficient attraction to pull the unlocking pins  108  and  208  from release mechanisms  130  and  240 . The preferred floating structure  112  and  212  is a hollow cylindrical tube constructed from a chemical resistant plastic material. The tube is approximately 5/16 inch in diameter and 4 inches long with 1 mm wall thickness. It is sealed on one side and the other side is similarly sealed with a magnet affixed to the end. The magnet is a neodymium cylinder ¼″×¼″ rare earth magnet. The buoyancy is provided by the air in the tube. The buoyant force on a submerged object is equal to the weight of the fluid that is displaced by the object. For example, if the floating structure is placed in diesel, and the amount of diesel displaced by the floating structure is heavier than the floating structure, then the floating structure will float. If the floating structure is placed in gasoline and the amount of gasoline displaced by the floating structure is lighter than the floating structure, then the floating structure will sink. To construct a floating structure that floats in diesel and sinks in gasoline the gravity of the floating structure should be somewhere between the gravity of the diesel fuel and the gravity of the gasoline fuel. Typical density of diesel fuel is around 0.850 g/cm 3 . The density for gasoline fuel is around 0.735 g/cm 3  and 0.755 g/cm 3 . For this combination the buoyancy for the floating structure should be around 0.800 g/cm 3 . To achieve the desired volume weight, the proportions of the floating structure will vary depending on the material being used to construct it. The floating structure can also have two or more spacers mounted on its side to keep the floating structure in the middle of activation tubes  104  and  204 . The spacers are usually made of the same materials as the floating structure&#39;s tube (not shown). In the alternative, the buoyancy can be provided by the tube material itself and the tube can be a solid material of any shape. Since the density of gasoline and diesel is affected by temperature it is also possible to use two floating structures, one for winter and one for summer with slightly different buoyancies. Although, a preferred embodiment of the floating structure for diesel and gasoline is described above, many other embodiments can be used to accomplish the same results for other fluids that are well known in the art. 
   Stoppers  116  and  216  are designed to stop the flow of the liquid when TPL  100  and  200  is activated. The configuration of stoppers  116  and  216  can be designed to resemble the inner portion of filler tubes  118  and  218 . Although, the figures show a two-piece configuration for stoppers  116  and  216 , other configurations, which are well known in the art, can be used. 
   There are several alternative embodiments for the present invention. In the invention of  FIGS. 1 and 2 , small exit aperture  122  can be just an exit hole and one or several drain holes can be added to the bottom of activation tube  104 . In addition several air release apertures could be added as part of activation tube  104 . On the upper opening of activation tube  104 , a cover can be placed with smaller or bigger openings to control the flow speed of activation tube  104  and to reduce turbulence inside activation tube  104 . Unlocking pin  108  can be placed inside or outside activation tube  104  and it does not have to be a pin, it can also be made of a flexible material like rope, chain, wire, etc. It can also be made out of a tube positioned inside activation tube  104  with an opening in the upper part and bottom part, and it could be used as an unlocking pin and an exit for the air  310  activated by floating structure  308 , at the same time as shown in  FIG. 5 . 
   An alternative embodiment of the invention as shown in  FIG. 6 , liquid injector  326  can have one or several tubes extending into activation tube  204  and one or several injectors can be placed outside activation tube  204 , as shown in  FIG. 6 . Any of these changes with different combinations are possible. It will not change the basic operation of the invention, but it would extend or reduce the activation time of the flow stopping action. 
   The present invention can be used in other applications where it is possible to mix liquids with different densities and the liquids are introduced by gravity or pumped. The invention shuts down the flow of the wrong liquids within 3 or 4 seconds from the start of the flowing procedure. 
   Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above, are hereby incorporated by reference.