Abstract:
A connector system for reducing particulate matter may include a first unit for supplying signals and a second unit for receiving and/or relaying the signals. The signals may be for power generation and/or communications. A coupling may be positioned between the first unit and second unit. The coupling may include a center pin attached to the first unit and for receiving a signal at a first potential. The coupling may further include an outer case attached to the first unit and for receiving a signal at a second potential. The coupling may also have a seal and a spring. The seal and spring may surround the outer case. The spring may engage the second unit and may pass signals between the first unit and the second unit. The spring may comprise a canted coil spring for supporting load forces and for passing electrical current.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. provisional patent application Ser. No. 61/704,698, filed Sep. 24, 2012, which is herein incorporated by reference. 
     
    
     DESCRIPTION OF THE RELATED ART 
       [0002]    Some radiation generators, such as the neutron generators for the oil field services industry, are particularly limited in size and shape. These radiation generators often use high voltage power supplies. To ease manufacturing of the neutron generators and their respective power supplies, each high voltage power supply and the radiation tube for the neutron generator are usually assembled separately and connected during the last steps of the assembly. 
         [0003]    Making a connection between the radiation tube and power supply for a neutron generator easily “breakable” allows the manufacturing and the maintenance of such systems having these two components much easier. However, separate physical components may be challenging in order to fulfill all end-use environmental requirements (space, ruggedness, etc.), such as those found in rough environments, like an oil drilling operation. 
         [0004]    Some breakable designs employ springs which may have push buttons to disengage the two elements. In such configurations, the spring and the button usually must be “protected” behind a metal part in order to prevent corona discharge. Consequently, under shock and vibration in rough environments, like in a drilling operation, the button will usually hit and rub on internal parts of the assembly which often creates metal dust. 
         [0005]    In other conventional solutions, the spring may be removed while the button may be substituted with a slightly oversized version made from conductive rubber. Such a conventional solution may reduce metal dust but usually such a design may create conductive rubber particulates which may have the same effect as the metal dust problem described above. 
         [0006]    Due to these issues, other conventional solutions have been redesigned and replaced with a hardwired solution which may make the assembly thereof somewhat difficult. One main reason for the failures of the conventional designs which generate metal dust and/or conductive rubber particulates is the fact that the two parts may often move with respect to each other in high vibration/shock environments, such as in an oil drilling context. As these two parts move with respect to each other, they can easily hit and rub each other which may lead to wear and the generation of particulate materials which may contaminate the electrical environment, and in some cases, establish the potential for corona discharge or a high voltage breakdown. 
       SUMMARY OF THE DISCLOSURE 
       [0007]    A connector system for reducing particulate matter may include a first unit for supplying electrical power and/or communication signals and a second unit for receiving the electrical power and/or relaying the communication signals. A breakable coupling may be positioned between the first unit and second unit. The coupling may include a center pin attached to the first unit and for receiving signals at a first potential. The coupling may further include an outer case attached to the first unit and for receiving signals at a second potential. The coupling may also have a seal and a spring. The seal and spring may surround the outer case. The spring may engage the second unit and may pass the electrical power at the second potential between the first unit and the second unit. The spring may comprise a canted coil spring for supporting load forces and for passing electrical current. However, other springs, such as, but not limited to, leaf springs, fingerstocks, and appropriately shaped wire springs (round, polygonal shape, oval shape, or others) may be employed. 
         [0008]    The first unit may comprise a power supply for an electronic radiation generator used in an oil well drilling environment. Electronic radiation generators may use high voltages at about or above 50 kV. This high voltage power supply may be connected to a radiation tube (that may comprise a neutron tube, an x-ray tube, or other similar radiation tube). The radiation tube may be the second unit referenced above and described below. For ease of manufacturing, the high voltage power supply and the radiation tube may be assembled separately and then joined together in an insulated housing. There are several ways to connect these two subassemblies. 
         [0009]    The inventive method and system may comprise at least one way to connect the two subassemblies, as described above, that includes the high voltage power supply and the radiation tube. The inventive connector system may be decoupled easily but it may limit any amount of dust that may be created by incidental rubbing of materials of the system during vibration. The inventive method and system may trap dust in areas of the connector which is not as sensitive to the high voltage environment. 
         [0010]    This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    In the Figures, like reference numerals refer to like parts throughout the various views unless otherwise indicated. For reference numerals with letter character designations such as “ 102 A” or “ 102 B”, the letter character designations may differentiate two like parts or elements present in the same figure. Letter character designations for reference numerals may be omitted when it is intended that a reference numeral to encompass all parts having the same reference numeral in all figures. 
           [0012]      FIG. 1A  is a schematic view of a downhole logging tool and associated surface instrumentation; 
           [0013]      FIG. 1B  is a diagram of a neutron generator illustrated in  FIG. 1A  and which has an inventive connector system; 
           [0014]      FIG. 2A  is a cross-sectional view of one aspect of an inventive connector system that may couple the high voltage power supply and the radiation tube illustrated in  FIG. 2A ; 
           [0015]      FIG. 2B  is a side view of a spring that may be employed in the inventive connector system illustrated in  FIG. 2A ; 
           [0016]      FIG. 2C  is a flow chart illustrating a method for reducing and/or eliminating particulate matter in connector systems for a wellsite drilling operation. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Referring initially to  FIG. 1A , a neutron generator  10  may be used as part of a logging tool  111  as shown. The logging tool  111  may be used in a drilling operation as understood by one of ordinary skill in the art. 
         [0018]    The neutron generator  10  may be housed in a sonde  118 . The sonde  118  may include electrical components, e.g., downhole telemetry circuits  112 , neutron generator control circuitry  114 , at least one radiation detector (for example, two shown as  116 A,  116 B) and possibly other system components are housed within the sonde  118 . The sonde  118  may be configured to be drawn through a borehole  120 . 
         [0019]    The borehole  120  is illustrated as including a steel casing  122  and a surrounding cement annulus  124 . The sonde  118 , in many situations, is suspended in the borehole  120  by cable, coiled tubing or other means (labeled  126 ). A multi-conductor power supply cable  130  is carried by the suspension means  126  and provides electrical power from the surface (provided by power supply circuitry  132 ) downhole to the sonde  118  and the electrical components therein, which include the downhole telemetry circuits  112 , neutron generator control circuitry  114 , radiation detectors  116 A,  116 B, and the neutron generator  10 . 
         [0020]    The neutron generator  10  may comprise the inventive connector system  204  (illustrated with dashed lines in  FIG. 1A ) described in further detail below. The neutron generator  10  is, in most cases, operated to emit neutrons in order to irradiate the formation adjacent the sonde  118  with such neutrons. Neutrons and/or photons that return from the formation are detected by the radiation detectors  116 A,  116 B. The output of the radiation detectors  116 A,  116 B are communicated to the surface by cooperation of downhole telemetry circuitry  112  and surface telemetry circuitry  132 , and analyzed by a signal analyzer  134  to obtain information regarding the formation  101 . 
         [0021]    Oil, gas, water and the elements of the geological formations  101  possess distinctive radiation signatures that permit identification of such geological formations  101 . The neutron generator  10  of this disclosure can be used in conjunction with other logging tools, such as those described in U.S. Pat. Nos. 4,794,792; 4,721,853; and 4,600,838; and 5,313,504. 
         [0022]      FIG. 1B  is a functional block diagram illustrating a high voltage power supply  206  coupled to a radiation tube  202  utilizing an inventive connector system  204 . The connector system  204  along with the high voltage power supply  206  and radiation tube  202  may form the neutron generator  10  as described above. 
         [0023]    As noted previously, the power supply  206  and the radiation tube  202  may be manufactured separately and in different locations. The power supply  206  and tube  202  may be coupled by the inventive connector system  204  before these elements are coupled together to form the neutron generator  10  and lowered down into a borehole  120  for a drilling operation. 
         [0024]      FIG. 2A  is a cross-sectional view of one aspect of an inventive connector system  204  that may couple the high voltage power supply  206  and the radiation tube  202  illustrated in  FIG. 2A . The high voltage power supply  206  referenced in  FIG. 2A  will be characterized as a second unit  206  while the radiation tube  202  will be characterized as a first unit  202 . The reason why these two elements have been generically characterized in this figure is because the inventive connector system  204  is not limited to the types of elements which are coupled together and connector system  204  is also not limited to the direction in which electrical current flows through the system  204 . 
         [0025]    The first unit  202  may be attached to the center pin  208  and a first outer case  224  of the connector system  204 . The center pin  208  may be separated from the first outer case  224  by a first insulating member  216  which circumnavigates a substantial portion or most of the pin  208 . The first insulating member  216  may keep the center pin  208  at a different electrical potential relative to a first body portion  210  which is part of the first unit  202 . 
         [0026]    A first electrical potential or voltage potential having a first polarity, like a negative polarity as indicated with a minus (“−”) sign in the drawings, may be supplied to a bottom portion of a receiving cylinder or hollow member  220  of the second unit  206  while a second electrical potential or voltage having a second polarity, like a positive polarity as indicated with a plus (“+”) sign in the drawings, may be supplied to the center pin  208 . The receiving cylinder  220  which receives and mates with the first outer case  224  both may have a negative polarity as indicated in the drawings. 
         [0027]    These potentials provided as illustrated in  FIG. 2A  may support power and/or bi- directional communications signals as understood by one of ordinary skill in the art. That is, the connector system  204  may support two-way communications signals or powering signals between the first unit  202  and second unit  204 , or both. 
         [0028]    The second unit  206  may comprise the receiving cylinder  220  which is designed to mate with or receive a second insulating member  223  that is part of the second unit  206 . The receiving cylinder or hollow member  220  mates with or receives the first outer case  224 . The second insulating member  223  of the second unit  206  may come in direct contact with the first insulating member  216  which surrounds the center pin  208  that is part of the first unit  202 . The second unit  206  may further comprise a second outer case  222  (having no shading) made from metal which receives and comes in direct electrical contact with the center pin  208  described above. 
         [0029]    The first outer case  224  for the first unit  202  may comprise a first groove  232  that may support a first fluid seal  212 A. The first fluid seal  212 A may comprise an O-ring. According to one aspect, this first groove  232  may be present in the first outer case  224  and not in the receiving cylinder  220  of the second unit  206 . In another aspect (not illustrated), the first groove  232  may be formed in either the outer case  224  or the receiving cylinder  220  or both. 
         [0030]    The center pin  208  may comprise a second groove  234  that may support a second fluid seal  212 B. The second fluid seal  212 B may also comprise an O-ring like the first fluid seal  212 A, however, this second fluid seal  212 B may have a diameter which is smaller than the diameter of the first fluid seal  212 A. The second groove  234  may be present in the center pin  208  and not in the second outer case  222  of the second unit  206 . However, according to another aspect (not illustrated), the second groove  234  may be present in either the center pin  209  or in the second outer case  222  or both. 
         [0031]    The first outer case  224  of the first unit  202  may further comprise a third groove  226  that supports a first canted coil spring  214 . This third groove  226  may be present in both the first outer case  224  of the first unit  202  and the receiving cylinder  220  of the second unit  206 . With the third groove  226  present in both the first outer case  224  of the first unit  202  and the receiving cylinder  220  of the second unit  206 , then the canted coil spring  214  may provide for a latching contact between these two members. 
         [0032]    The center pin  208  of the first unit  202 A may further comprise a fourth groove  228  that supports a second canted coil spring  218 . However, this second canted coil spring  218  may be designed to provide an electrical contact and not any mechanical latching function. Such a design may be achieved when the fourth groove  228  is present within either of the center pin  208  or the second outer case  222  for the second unit  206 . However, one of ordinary skill in the art recognizes that the second canted coil spring  218  may be provided to support a mechanical latching function in other alternative embodiments not illustrated. 
         [0033]    The first canted coil spring  214  may provide a first electrical contact and at the same time locks the receiving cylinder  220  of the second unit  206  to the first outer case  224  of the first unit  202 . The second, non-latching canted coil spring  218  provides a second electrical contact between the center pin  208  and the conduct of outer case  222  of the second unit  206 . Each canted coil spring  214 ,  218  may comprise an off-the-shelf product, such as, but not limited to, springs sold as of this writing as models of the 10X series as shown in the catalog DM9 by Bal seal Engineering Inc. (of Pauling Foothill Ranch, Calif.). 
         [0034]    The two canted coil springs  214 ,  218  may provide uniform loading when compressed radially or axially. The first canted coil spring  214  may deflect while producing loads which makes the first canted coil spring  214  suitable for latching and holding applications. The sliding/holding and connect/disconnect forces for each canted coil spring  214 ,  218  may be controlled by designing the grooves  224 ,  228  holding a respective spring  214 ,  218  as well as the size of each spring  214 ,  218 , wire diameter of each spring  214 ,  218 , and other spring characteristics to meet special mechanical requirements. 
         [0035]    Each canted coil spring  214 ,  216  may be designed to support the functions of holding, aligning, conducting, shielding and/or completing connections for electrical contacts. Each canted coil spring  214 ,  216  may support connect/disconnect force ratios ranging from about 1:1 to about 1:10. 
         [0036]    As noted previously, the first canted coil spring  214  may fulfill two functions of latching (see groove  226  in both parts—in center pin  208  and outer case  224 ) and it may serve as an electrical contact. The second and smaller diameter canted coil spring  218  may be used for an electrical contact (in which groove  228  is present in one of the parts which is the center pin  208  and not in the second conductive case  222  of the second unit  206 ). The latching design described above may have been used for both springs  214 ,  218 , but having just one spring, like first spring  214  serving as the single latching member, may reduce over-constraining of the connector system  204 . 
         [0037]    Since the first canted coil spring  214  loads the receiving cylinder  206  of the second unit  206  and the outer case  224  of the first unit  202  in a radial manner, this first canted coil spring  214  may center or physically align these two parts. Furthermore, the forces of this spring  214  may counter act against any forces due to shocks which may make the outer case  224  of the first unit  202  and receiving cylinder  220  of the second unit  206  hit or rub each other. 
         [0038]    In cases involving acceleration of the units  202 ,  206  and the connector system  204  such as in an oil drilling context which may defeat the force of the first spring  214 , the outer case  224  of the first unit  202  and receiving cylinder  220  of the second unit  206  may still rub and hit each other and possibly create dust and/or particulate matter. To prevent this dust from migrating into areas where it could weaken or damage the system  204 , a dual seal  212  comprising O-rings on either side of the springs  214 ,  218  may effectively trap any particulates/debris. 
         [0039]    In a slightly different embodiment, seals  212  may be replaced by overmolded rubber material. In addition to trapping the dust, the seals  212  may complement the springs  214 ,  218  to absorb any vibrations/shocks. 
         [0040]    Therefore, the connector system  204  may move with respect to the power supply  206  and/or the radiation tube  202 . Furthermore, in order to be able to unlatch the connector system  204  while disassembling the power supply  206 , the power supply  206 , in most cases, may need to apply a force on the connector system  204  greater than the latching force of the latching spring  214 . The system  204 , therefore, has a floating design with limited range. Once the connector system  204  hits the limits of its range of movement, the full force applied to the power supply  206  is transmitted to the connector system  206  and ultimately, to the latching spring  214 . 
         [0041]    A threaded hole  230  may be used to hold two pieces making up the center pin  208  and also to make up the electrical contact with a wire (not illustrated) originating from the first unit  202 . This threaded hole  230  and a corresponding screw (not illustrated) could be removed or replaced with slight variations of the design. 
         [0042]    Each of the conductive materials illustrated may be manufactured from metal, such as, but not limited to, steel, aluminum, copper, etc. The conductive materials illustrated in  FIG. 2B  include the center pin  208 ; the first and second canted coil springs  214 ,  218 ; the first outer case  224 ; the contact  210 ; the receiving cylinder  220 ; and the second outer case  222  for the second unit  206 . The non-conductive materials illustrated may be manufactured from conventional dielectric materials such as rubber, plastic, ceramics, and the like. The non-conductive materials illustrated in  FIG. 2A  have been shaded with thin and thick lines. The non-conductive materials include the first insulating member  216 , the second insulating member  224  for the second unit  202 , and the seals  212 . 
         [0043]      FIG. 2B  is a side view of a spring  214 ,  218  that may be employed in the inventive connector system  204  illustrated in  FIG. 2A . As noted above, the springs  214 ,  218  may comprise canted coil springs. The canted coil springs  214 ,  218  may provide uniform loading when compressed radially or axially. The canted coil springs  214 ,  218  are useful embodiment, however, other structures such as, but not limited to, a leaf spring (including fingerstock), or an appropriately shaped round wire spring (polygonal shape, oval shape or other) may be employed without departing from the scope of this disclosure. 
         [0044]      FIG. 2C  is a flow chart illustrating a method  300  for reducing and/or eliminating particulate matter in connector systems  204  for a wellsite drilling operation. Block  305  is the first block of method  300 . In block  305 , a coaxial connector layout may be provided such as illustrated in  FIG. 2A  described above. Next, in block  310 , a first spring  214  may be provided for latching and as an electrical contact. Subsequently, in block  315 , a second spring  218  may be provided to supply an electrical contact and not any latching function as described above in connection with  FIG. 2A . This electrical current may comprise power signals or communication signals or both. In block  320 , the two springs  214 ,  218  may be enclosed with a fluid seal  212  in order to substantially reduce the flow of particulate matter created during vibration of the connector system  204  as described above. The method  300  then ends. 
         [0045]    With this inventive connector system  204  and method  300 , high-voltage contacts may be supported in which the electrical contacts must remain together for long periods of time. The inventive connector system  204  and method  300  may compensate for any thermal expansion mismatch between the different elements (i.e., such as the radiation tube  202 , and housing for the high voltage power supply  206 . 
         [0046]    The inventive connector system  204  and method  300  may endure environmental abuse in an oil drilling context (such as shock vibration, high and low temperature, thermal cycling, etc.). The inventive connector system  204  and method  300  may be designed to fit within a very limited space while also eliminating or substantially reducing any corona discharge. With the inventive connector system  204  method  300 , assembly and disassembly of the units  202 ,  206  being connected may be accomplished very easily. 
         [0047]    Certain steps in the processes or process flows described in this specification naturally precede others for the system and method to function as described. However, the system and method are not limited to the order of the steps described if such order or sequence does not alter the functionality of the system or method. That is, it is recognized that some steps may be performed before, after, or in parallel (substantially simultaneously with) other steps without departing from the scope and spirit of the disclosure. In some instances, certain steps may be omitted or not performed without departing from the system or method. Further, words such as “thereafter”, “then”, “next”, etc. are not intended to limit the order of the steps. These words are simply used to guide the reader through the description of the sample methods described herein. 
         [0048]    Although only a few embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from this system or method. 
         [0049]    For example, a coaxial and cylindrical arrangement are illustrated in  FIG. 2A . The geometrical shape for several members of the system  224  may be different than what is illustrated. That is, the shape for the receiving cylinder/hollow member  220  could be oval or square on the outside and contain two or more inner connections that are shaped to match the first outer case  224 , which could remain to have a cylindrical shape. 
         [0050]    Also, while only a single connector system  224  is illustrated in  FIG. 2A , multiple systems  224  may be used in parallel with one another between the two units  202 ,  206 . Further, multiple inner connections, such as the outer case  224  and center pin  208 , could be nested coaxially, be put side-by-side, or arranged in a pattern as understood by one of ordinary skill in the art. 
         [0051]    Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. 
         [0052]    In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, sixth paragraph for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.