Abstract:
According to embodiments of the invention, a submersible pump cable includes a conductive air line that is configured to transport both an electrical current and pressurized air.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of copending U.S. application Ser. No. 10/925,665, filed on 24 Aug. 2004, entitled SUBMERSIBLE PUMP CABLE WITH AIR LINE. 
     
    
     BACKGROUND  
       [0002]     1. Technical Field  
         [0003]     This disclosure relates in general to submersible cables for pump applications, and more particularly, to improved submersible cables that have a combined air line and electrical lead.  
         [0004]     2. Description of the Related Art  
         [0005]     Submersible pump cable is well-known in the art. As the name implies, submersible pump cable is used to supply electrical power to submersible pumps. Submersible pump cable is used within the well casing, and a typical operating environment with temperatures between −40° and 75° C., in circuits not exceeding 600 V. One type of submersible pump cable, known as the twisted type, consists of four copper conductors, either solid or stranded, that are insulated with a PolyVinyl Chloride (PVC) sheath. The conductors and their PVC sheaths have a circular cross-section. One of the conductors is typically used as a ground connection. The four conductors, with their associated sheaths, are twisted around each other to form the submersible pump cable.  
         [0006]     Another type of submersible pump cable used for heavy duty applications is the flat jacketed type. For this type of cable, each of the conductors and their PVC sheaths are laid out side-by-side, that is, parallel to each other. A flat PVC jacket is disposed around the outside of the circular PVC sheaths. The flat PVC jacket provides an additional measure of abrasion resistance.  
         [0007]     Because the water table varies throughout the year, it is oftentimes desirable to know how much water is available to pump. For example, a submersible pump may be at the bottom of a well that is 300 feet deep. During a wet winter, the water table may be, for example, 50 feet below the ground surface. In other words, the pump is submerged under 250 feet of water. During a dry summer, however, the water table may drop, for example, by 50 feet. Consequently, the pump is now submerged under 200 feet of water.  
         [0008]     Based upon the amount of water that is available, a pump may be adjusted to operate at a selected pumping rate. For example, one particular pump may be adjusted to pump between 5 gallons/minute to 100 gallons/minute. Other pumps may have different pumping rates. The fastest pumping rate might be used when the submerged depth of the pump is at a maximum and the slowest pumping rate might be used when the submerged depth of the pump is at a minimum.  
         [0009]     A conventional way of determining how deep the pump is submerged below the surface of the water is by using an air line. The air line is nothing more than a hollow tube. One end of the air line is attached to the pump when it is submerged, but the end of the air line remains open to allow liquid and gas to pass through the end of the air line. The other end of the air line may be coupled to a pressure gauge and an air pump. The air pump is configured to occasionally pump air through the air line until all the liquid is expelled from the air line. The pressure gauge records the air pressure required to clear the liquid from the air line.  
         [0010]     It is well known that 1 pound per square inch (p.s.i.) of pressure will raise a column of water by 2.31 feet. Conversely, a column of water 1 foot tall exerts a pressure of 0.434 p.s.i. Using these figures and the air pressure that was recorded by the pressure gauge, a calculation of the depth that the pump is submerged may be obtained. For example, if the pressure gauge records a pressure of 27.0 p.s.i., the pump lies submerged at a depth of 63.0 feet [(27.0 p.s.i.)×(2.31 feet/p.s.i.)=62.99 feet].  
         [0011]     Currently, conventional air lines and conventional submersible pump cables are manufactured separately. Embodiments of the invention address this and other disadvantages of the conventional art. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective diagram illustrating a flat jacket submersible pump cable that is combined with an air line according to some embodiments of the invention.  
         [0013]      FIG. 2  is a perspective diagram illustrating a twisted submersible pump cable that is combined with an air line according to other embodiments of the invention.  
         [0014]      FIG. 3  is a perspective diagram illustrating a flat jacket submersible pump cable having a conductive air line according to some other embodiments of the invention.  
         [0015]      FIG. 4  is a perspective diagram illustrating a conductive air line suitable for use with submersible pump cables according to some other embodiments of the invention.  
         [0016]      FIG. 5  is a cross-sectional diagram illustrating a twisted type submersible pump cable having a conductive air line according to some other embodiments of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]     Embodiments of the invention provide a combined submersible pump cable and air line. Consequently, the air line benefits from being protected by one or more of the conductors, PVC sheathing, and/or PVC jacket of the submersible pump cable. By incorporating the pump cable and air line into one combined cable, embodiments of the invention provide additional convenience and increased protection to the air line compared to the conventional art.  
         [0018]     In the following detailed description, numerous exemplary embodiments of the invention will be described with reference to the attached FIGURES. Although the specification below may refer to “an”, “one”, “another”, or “some” embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature described only applies to a single embodiment.  
         [0019]      FIG. 1  is a perspective diagram illustrating a flat jacket submersible pump cable that is combined with an air line according to some embodiments of the invention.  
         [0020]     The submersible pump cable  100  includes four conductors  110  and one air line  130 . The conductors  110  may be composed of a single large copper wire or many small strands of copper wire twisted together. In alternative embodiments other metals may be used to form the conductors  110 .  
         [0021]     The conductors  110  are surrounded by PVC sheaths  120  that have ring-shaped cross sections. As shown in  FIG. 1 , the air line  130  may itself be a PVC sheath that has a ring-shaped cross section. The air line  130  defines a circular void  135  that runs the length of the air line  130 . The circular void  135  and the air line  130  together form the hollow tube that is used to measure the height of the water above the submersible pump.  
         [0022]     The submersible pump cable  100  also includes a flattened PVC jacket  140  that is disposed around the PVC sheaths  120  and the air line  130 . The PVC jacket  140  holds the PVC sheaths  120  and the air line  130  in a side by side, parallel configuration.  
         [0023]     Although in these embodiments the air line  130  is positioned centrally among the conductors  110 , alternative embodiments may have the air line  130  in a different position relative to the conductors  110  and PVC sheaths  120 .  
         [0024]     Consequently, according to the embodiments described above, a submersible pump cable  100  of the flat jacket type may also include an air line  130  within the PVC jacket  140 , thus providing additional durability to the air line  130 . Additional convenience is provided because the air line  130  is incorporated into the submersible pump cable  100 , and the open end of the air line  130  is automatically positioned in a location that is in close proximity to the submerged pump. Thus, a conventional pressure gauge may be attached to the upper end of the air line  130  without the hassle of making sure that the end of a conventional air line is positioned in close proximity to the submerged pump or properly secured to a conventional pump cable.  
         [0025]      FIG. 2  is a perspective diagram illustrating a twisted submersible pump cable that is combined with an air line according to other embodiments of the invention.  
         [0026]     A submersible pump cable  200  includes four conductors  210  and one air line  230 . The conductors  210  may be composed of a single large copper wire or many small strands of copper wire twisted together. In alternative embodiments other metals may be used to form the conductors  210 .  
         [0027]     The conductors  210  are surrounded by PVC sheaths  220  that have ring-shaped cross sections. The air line  230  may itself be a PVC sheath that has a ring-shaped cross section. The air line  230  defines a circular void  235  that runs the length of the air line  230 . The circular void  235  and the air line  230  together form the hollow tube that is used to measure the height of the water above the submersible pump.  
         [0028]     In the embodiments illustrated in  FIG. 2 , the conductors  210  and their protective PVC sheaths  220  are twisted around the air line  230 , thereby protecting it from abrasion. This is the preferred embodiment. However, in alternative embodiments the air line  230  may be in a different position relative to the conductors  210  and PVC sheaths  220 . That is, instead of being centrally located among the twisted conductors  210  and PVC sheaths  220 , the air line  230  may itself be twisted together with the conductors  210  and sheaths  220 .  
         [0029]     Consequently, according to the embodiments described above, a submersible pump cable  200  of the twisted type may also include an air line  230  centrally located among the twisted conductors  110 , thus providing additional durability to the air line  230 . Additionally, since the air line  230  is now part of the submersible pump cable  200 , the open end of the air line  230  is automatically positioned in a location that is in close proximity to the submerged pump. Thus, a conventional pressure gauge may be attached to the upper end of the air line  230  without the hassle of making sure that the end of a conventional air line is positioned in close proximity to the submerged pump or properly secured to a conventional pump cable.  
         [0030]      FIG. 3  is a perspective diagram illustrating a flat jacket submersible pump cable  300  having a conductive air line  330  according to some other embodiments of the invention.  
         [0031]     Referring to  FIG. 3 , the submersible pump cable  300  includes three conductors  310  and one conductive air line  330 . The conductors  310  may be composed of a single large copper wire or many small strands of copper wire twisted together. The conductors  310  are surrounded by insulating sheaths  320  that have ring-shaped cross sections. In some embodiments of the invention, the insulating sheaths  320  may be composed of PVC.  
         [0032]     The conductive air line  330  defines a circular void  335  that runs the length of the conductive air line. The circular void  335  and the conductive air line  330  together form the hollow tube that is used to measure the height of the water above the submersible pump. The conductive air line  330  may be composed of flexible copper tubing, or of some other conductive metal. Thus, the conductive air line  330  is used to supply an electrical signal to the submersible air pump as well as to measure the height of the water above the air pump.  
         [0033]     The submersible pump cable  300  also includes a flattened insulating jacket  340  that is disposed around the insulating sheaths  320  and the conductive air line  330 . The insulating jacket  340  holds the insulating sheaths  320  and the conductive air line  330  in a side by side, parallel configuration. In some embodiments of the invention, the insulating jacket  340  may be composed of PVC.  
         [0034]     In alternative embodiments of the invention, one or more of the conductors  310  and its corresponding insulating sheath  320  may be replaced by another conductive air line  330 . The total number of conductors  310  and conductive air lines  330  present in the submersible pump cable  300  may be more or less than the embodiment illustrated in  FIG. 3 .  
         [0035]     According to other embodiments of the invention, a submersible pump cable may have a number of conductive air lines  330  and no conductors  310 /insulating sheaths  320  whatsoever. In the event that one of the conductive air lines  330  was ever damaged to the point where it ceased to effectively conduct current and/or hold air, an unused conductive air line  330  may be used. For example, for a conventional submersible pump that required four electrical connections and one air tube, a submersible pump cable consisting of six conductive air lines  330  would provide five spare air tubes and two spare electrical connections.  
         [0036]      FIG. 4  is a perspective diagram illustrating another conductive air line  400  suitable for use with submersible pump cables according to still other embodiments of the invention. According to these embodiments, the conductive air line  400  consists of a conductive metal sheath  420  covering an air line  430 . In some embodiments, the air line  430  may be composed of plastic. The air line  430  defines a circular void  435  that runs the length of the air line. The circular void  435  and the air line  430  together form the hollow tube that is used to measure the height of the water above the submersible pump. In  FIG. 4 , the conductive metal sheath  420  is shown stripped off of the air line  430  for illustrative purposes.  
         [0037]     The conductive metal sheath  420  covering the air line  430  preferably consists of a conductive metal such as, e.g., copper. The conductive metal sheath  420  is used to provide an electrical connection to an attached submersible pump (not shown). The conductive metal sheath  420  may increase the durability of the air line  430  by protecting it from abrasion. In alternative embodiments of the invention, the conductive metal sheath  420  may consist of a number of smaller, braided metal strands that surround the air line  430 . For example, the conductive metal sheath  420  may consist of a braided copper sheath surrounding the air line  430 .  
         [0038]     The conductive air line  400  may be incorporated into a flat jacket type submersible pump cable, for example, like the submersible pump cable  100  of  FIG. 1 . In this case the flat jacket type submersible cable will have a flattened PVC jacket that is similar to the PVC jacket  140  of  FIG. 1 . The PVC jacket further protects the conductive air line  400  and also prevents the conductive metal sheath  420  from being exposed to the surrounding liquid.  
         [0039]     In alternate embodiments, the conductive air line  400  may be incorporated into a twisted type submersible pump cable, for example, a twisted type submersible cable like the submersible pump cable  200  of  FIG. 2 . In this case the conductive air line  400  preferably has an additional insulative sheath (not shown) surrounding the conductive metal sheath  420  to further protect the air line  430  and also to prevent the conductive metal sheath  420  from being exposed to the surrounding liquid.  
         [0040]      FIG. 5  is a cross-sectional diagram illustrating a twisted type submersible pump cable  500  having a conductive air line  550  according to still other embodiments of the invention.  
         [0041]     Referring to  FIG. 5 , the submersible pump cable  500  includes three conductors  510  and one conductive air line  550 . The conductors  510  may be composed of a single large wire made of conductive metal, such as copper, or they may be composed of many smaller strands of conductive metal wire. The conductors  510  are surrounded by insulating sheaths  520  that have ring-shaped cross sections. In some embodiments of the invention, the insulating sheaths  520  may be composed of PVC.  
         [0042]     The conductive air line  550  defines a circular void  555  that runs the length of the conductive air line. The circular void  555  and the conductive air line  550  together form the hollow tube that is used to measure the height of the water above the submersible pump. The conductive air line  550  may be composed of flexible copper tubing, or of some other conductive metal. Thus, the conductive air line  550  is used to supply an electrical signal to the submersible air pump as well as to measure the height of the water above the air pump.  
         [0043]     Although not shown in  FIG. 5 , the conductive air line  550  and the conductors  510 /insulating sheaths  520  are twisted around each other, similar to the submersible pump cable  200  illustrated in  FIG. 2 . Finally, an insulating jacket  560  surrounds the twisted conductive air line  550  and the insulating sheaths  520  to further protect the conductive air line  550 . In some embodiments of the invention, the insulating jacket  560  may be composed of PVC.  
         [0044]     Similar to the embodiments of the invention described in  FIGS. 1 and 2 , the embodiments described in  FIGS. 3, 4 , and  5  incorporate an air line directly into the submersible pump cable.  
         [0045]     Having described several exemplary embodiments of the invention, it should be apparent that modifications and variations of the described embodiments that do not depart from the inventive concepts disclosed above will be obvious to those of skill in the art.  
         [0046]     For example, the flat jacket type of submersible pump cable and the twisted type of submersible pump cable described above are just two examples of submersible pump cables. Other embodiments of the invention may include an air line together with another type of submersible pump cable.  
         [0047]     As yet another example, embodiments of the invention may also include more than one air line in the submersible pump cable. This would provide a backup air line if one of them became damaged or clogged.  
         [0048]     As another example, in the embodiments described above with respect to  FIG. 1  the protective PVC sheaths for the conductors had approximately the same diameter as the air line. In alternative embodiments, such as the embodiments described in  FIG. 2 , the diameter of the PVC sheaths may be smaller or larger than the diameter of the air line.  
         [0049]     As another example, the embodiments described above were assumed to be used in water pumping application. However, the embodiments described above may work equally well in applications where a liquid other than water is being pumped.  
         [0050]     Finally, it should be apparent that even though the embodiments described above used copper conductors and PVC for the insulating material, alternative embodiments may use conductors of different metals and insulating material of different types.  
         [0051]     Consequently, the scope of the invention should not be limited only to the embodiments described above, but to all embodiments as defined and encompassed by the attached claims.