Abstract:
This disclosure is directed to a backpack comprising a frame with straps and surrounding side wall for easy attachment on a diver. A first gas storage tank stores either oxygen or air, which is input through an inlet line. With a pressure regulator, it delivers a flow of gas to feed the diver while diving. As the pressure drops in the gas tank, a secondary source of oxygen is then operated and delivers a flow of oxygen to the diver so that the diver is able to receive supplemental oxygen stored in the gas storage tank formed by electric current flowing through a pair of spaced terminals. The terminals form oxygen by disassociation of water. The oxygen is bubbled upwardly in a chamber, pass though a hydrophobic valve, delivered into the gas storage tank, and supplements the oxygen supply.

Description:
BACKGROUND OF THE DISCLOSURE 
     This disclosure is directed to a backpack for use by a diver. The backpack is sized so that it fits on the back of an average sized adult. It is supported at a convenient location. It provides assistance to the diver in several ways. First, it is equipped with a battery which is electrically charged on the shore. The backpack includes two tanks in it. One is reserved for oxygen. It can be precharged on shore. It can be charged with pure oxygen or with air from the atmosphere to provide an initial charge of oxygen. The backpack thus provides a charged cylinder filled with air or oxygen which enables the user to stay under water for a specified interval. When that tank runs low, the system then notes the drop in tank pressure, and at that time switches on a battery. The battery in conjunction with two electrodes deployed at spaced locations in a chamber then receives water and converts that water into oxygen and hydrogen. The two electrodes are spaced apart. They are located at a spacing prompting the bubbles to rise in the chamber. The bubbles formed by the disassociation of water into the two component gases are segregated by appropriate electrode spacing in the chamber. This enables the oxygen to be collected, compressed and stored to the tank for the diver. This will extend the duration of use. 
     Interestingly, the hydrogen which is formed by the disassociation can be used in any one of three different ways. Among other things, it can be used to power a motor, or it can be used as an expansion chamber fluid. By inflating an expansion chamber, thereby making the backpack larger, buoyancy is changed. The buoyancy prompts a force floating the diver because the change in the buoyancy of the backpack will then help bring the diver back to the surface. Accordingly, the hydrogen created by the disassociation will later, nevertheless, have value. The value of the hydrogen is therefore appropriately noted and is used in any of the several ways just mentioned. 
     To put a scale on this structure, assume that the system incorporates an oxygen tank which holds an adequate supply. By positioning a battery in the backpack and using the battery for water disassociation into oxygen, the same tank can be steadily recharged while the diver is consuming the gas of the original charge. Commonly, the equipment would have to be retrieved to the surface after a typical one hour interval. Through the use of the disclosed system, a continuous recharge can be initiated. The swimming interval can be extended to the extent that the charge in the battery permits. 
     In one important aspect, the present apparatus is a completely self contained mobile device which does not impede or otherwise slow down the diver. It is a system which is relatively compact. While compact, it can be constructed readily for easy mounting on the back so that the swimmer is not aware that it is present. Yet, while small and compact, it can carry a charge which is able to sustain the swimmer for a much longer interval. To be sure, heavy wall, high pressure gas cylinders can be used to extend the swimming duration. These heavy cylinders may seem easy to handle under water. They are, however, often made of very thick walls to define a relatively heavy structure. In this instance, a lighter gauge storage tank can be used. While lighter in wall thickness and lighter in total weight, a longer duration is obtained through the use of the battery powered system which furnishes a discharge of oxygen so that a small tank or a large tank at a lower pressure, hence a lighter weight tank, can be progressively refilled during use. Since refilling occurs ratably, the system of the present disclosure need not operate at high speed. Rather, it can generate enough oxygen to make up for oxygen consumption at a controlled rate, a rate typically in the range of 25% to 60% of the rate at which the swimmer requires oxygen. By using it as a booster to add to an initial charge, smaller equipment can be used. Thinner walls in the equipment can be used so that the aggregate weight in reduced. Finally, it has the value of forming an added byproduct (hydrogen gas) which can be used elsewhere in the system. One use of the generated hydrogen is to power a motor which assists the swimmer by providing a motive force. Another use operate a hydrogen or gas powered motor to sound a motor powered marker such as an alarm marker. Another use is to inflate an expansion chamber so that buoyancy can be increased at the flip of a switch, thereby changing the buoyancy of the diver and quickly returning the diver to the surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     So that the manner in which the above recited features, advantages and objects of the present invention are attained can be understood in detail, more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. 
     It is to be noted, however, that the appended drawings illustrate only typical embodiments of the invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
     The single drawing shows the backpack of the present invention which incorporates oxygen forming equipment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Attention is now directed to the only drawing which shows a backpack  10  constructed in accordance with the present disclosure. It is mounted with a strap  12  reaching around the user. The strap  12  connects with a suitable clasp or buckle  15  which grabs the other end of the strap. One or two straps are typically used. The straps can reach around the waist, around the chest, or they can extend up and over the shoulders and reach around the arms, all as desired by the user. Leg straps also can be conveniently incorporated. As illustrated in the only drawing, the backpack is constructed on a diver supported mounting frame  14  which is essentially a covered board or frame contacted against the back of the user. Typically, the backpack covers the region of the back extending from just below the shoulders down to the area of the waist, and perhaps a bit lower to the hips of the user. The frame  14  defines a structure which is encompassed within a side wall  16 . The side wall  16  has a specified height so that there is an adequate depth within the backpack. The backpack includes a number of components which are mounted on the frame  14 . The components have a size so that they fit within the side wall  16 . The side wall  16  is solid on most of the periphery. The side wall  16  cuts straight across at the top in a segment  18 . The frame  14  also extends up to the straight wall segment  18 . There is a collapsible expansion chamber there which will be discussed in some detail later. 
     The backpack has a small opening at the lower end which opens into a water tank  20 . The tank  20  is provided with water admitted through the opening  22 . The tank has two upwardly extending electrode chambers  21  and  23 . There are electrodes  24  and  26  in the tank. Electrodes  24  and  26  are connected with a battery  30 . The battery  30  is electrically wired so that the electrode  24  forms a disassociation gas product which is essentially oxygen. The oxygen is trapped so that it bubbles upwardly. In like fashion, the other electrode  26  forms a disassociation gas. It is also collected and accumulated, it being noted that both gases rise by gravity in the tank  20 . Preferably, this equipment is used where it is not inverted. There is the risk of collecting gases at the wrong raised portions of the chamber  20 . More will be noted concerning that hereinafter. 
     Duplicate systems are provided for removing the gases from the chamber  20 . The numeral  32  identifies a hydrophobic valve. This is a valve which permits the escape of gas collected in that part of the chamber. Typically, the hydrophobic valve is light weight and buoyant so that it rises if water comes up in that chamber. This prevents the escape of liquid through the valve  32 . It flows from the valve  32  into a pump  34 . The pump  34  is powered by a motor  36  which operates in a manner to be described. That compresses the oxygen to overcome the ambient pressure in the oxygen tank  40 . The tank  40  has an inlet line  38  which has an external fitting, thereby enabling the tank to be provided with an initial charge. An example will be given below. In addition to that, comparable equipment on the other side is also shown. It utilizes the valve  42  which again is a hydrophobic valve and that also operates in conjunction with a pump  44 . This enables the filling of the hydrogen tank  50  with the second gas made by the second electrode. Typically, the tank  50  is similar to the tank  40  except that it can be smaller. Also, it can be smaller and since it does not receive an initial charge, it can be constructed to operate at lower pressures. By that, it stores a much smaller volume and has a good deal less weight. 
     The tank  40  delivers oxygen out through a pressure regulator  52 . In turn, that delivers a flow of gas through the valve  54 . The valve  54  is connected with a gas supply line  56  which connects with the face mask  60 . The face mask provides oxygen for the swimmer. The pressure sensor  48  responds to pressure loss with time (as oxygen is burned) to turn on the battery  30  and start the process; it responds to the tank  40  pressure. 
     Consider a typical sequence of operations. Assume that the tank  40  is initially charged with gas. As a convenience, it can be provided with a mixture of oxygen at the ratio of anywhere from 20%, which is common in the atmosphere, up to maybe 50% or 60%. It is possible to mix the gas so that there is some neutral or essentially inert gas in the tank. The tank  40  is then used as the primary supply tank. As noted, it can be filled with 100% oxygen, or it can be initially charged with any lesser proportion. Assume that it is charged to an arbitrary pressure of 100 psi. While swimming occurs, flow is discharged through the pressure regulator and outlet valve. Flow is delivered through the gas supply line  56  into the face mask for use. Assume for purposes of discussion that the tank is discharged steadily by use from the initial charge of 100 psi. Assume arbitrarily that the pressure drops from 100 psi in the tank to 50 psi. This pressure drop is then sensed by a battery switch  62  which responds to the drop in pressure. It then operates, the dotted line connection in the drawing indicating that the battery switch  62  is operated to thereby connect the battery  30  to the two terminals. The water in the tank  20  is disassociated and forms a stream of oxygen in the form of oxygen bubbles. These bubbles rise and collect under the valve  32 . When there are enough bubbles at that area, they permit the valve to drop because it is a hydrophobic element, and thereby force the oxygen under the valve  32  up though the valve and then through the pump  34 . The pump  34  delivers the oxygen into the tank dependent on the back pressure. 
     There are conditions for which the pump does not need to operate. Consider as an example a diver who is at a depth of 200 feet. Roughly, the pressure at that depth is about 100 psi, ignoring the external atmospheric pressure factor. At an ambient water pressure of 100 psi, water is easily introduced into the tank  20  and continues to fill that tank as the water is disassociated. With the pressure in the tank  20  approximating the prevailing pressure outside the diver, the tank will then experience a pressure of 100 psi. The valve  32  will be forced upwardly by this water pressure as long as water acts against it and it is raised by its own buoyancy. When a large bubble of oxygen accumulates under the valve  32 , it will drop and make a transfer of the gas, not the water, through the pump  34  and into the tank  40 . If at that time the tank  40  pressure is less than the water pressure, there is no need to operate the pump  34 . On the other hand, if the pressure in the tank  40  is high, and it is higher than the prevailing water pressure outside the diver, then it may be necessary to selectively turn on the motor  36  and operate the pump to force oxygen past the valve  32  and into the storage tank  40 . 
     Essentially, the same kind of problem is encountered with the other electrode which forms a discharge of hydrogen gas. There is, however, a substantial difference as a result of the change in scale. The volume of hydrogen gas is much less, and it is much lighter per unit volume. The tank  50  is therefore much smaller. The tank  50  also need not operate at comparable dynamic pressures. If the tank  40  is safely constructed for 200 psi and is routinely operated with a very substantial safety margin, and if it has a capacity of five liters, the tank  50  preferably has a capacity of about one liter and is derated compared to the tank  40 . It can be constructed for operation at half the wall strength and half the pressure, and still have more than ample structural integrity for the task at hand. Moreover, the hydrogen discharge is delivered through a comparable valve  42  and a comparable pump  44 . Again, the same situation is faced, namely, the pump  44  may not be required because the back pressure in the tank  50  may be less than the ambient pressure at the depths of the swimmer. If the tank  50  is essentially at atmospheric pressure, the back pressure problem is substantially eliminated, and in that case, the pump  44  can be omitted or switched off, as the case may be. The hydrogen tank  50  has an associated pressure regulator  63 . It operates with a comparable valve  64 . In this instance, the valve is switched to any of several connections or positions. One use is delivery of the hydrogen from the tank  50  into an expansion chamber  70 . The chamber  70  is constructed to change the buoyancy of the diver. It is crushed or collapsed, it being observed that there is a flexible side wall  72  which extends to the full line shape illustrated, but collapses with a set of pleats represented by the dotted line representation in the drawing. By collapsing, the chamber  70  is reduced to a minimum volume. Expansion can be obtained by the elongation of a pair of expansion springs  74  which are located at the opposite ends of this chamber. Moreover, the expansion chamber in its initial condition is collapsed so that essentially it has nothing in it. The valve  64  connects to the expansion chamber  70  through a feed line  76 . The feed line  76  enables filling that chamber. Since it is filled with hydrogen gas, it is very light and creates a significant change in buoyancy. The chamber  70  is controllably activated by use of a latch  78  which is used by the diver to change the height of the chamber, hence, to change the buoyancy of the chamber. This chamber is optionally filled, as noted, by the gas vented through the line  76 . 
     Another destination for gas subject to control by the valve  64  is delivery of the gas to a motor  80 . The gas can be used simply as a flowing compressed gas to rotate a propeller. It is not uncommon for divers to assist it movement by using a motor driven propeller. This enables swimming at a faster rate. Alternately, the motor  80  can be connected to a motor powered marker  82 . By suitable connection of the motor  80  into the marker  82 , a noise maker can be operated. The noise maker can be used to mark the location of the diver, form signals to other divers in the vicinity, or can be used as a noise maker to frighten threatening fish and other aquatic life.