Abstract:
Systems and methods for automatically regulating the flow of fumes suctioned through a welding fume gun are provided. In certain embodiments, an automatic flow control assembly includes a vacuum system configured to suction a vacuum fume flow through an internal passage of a welding fume gun. The automatic flow control assembly also includes a sensor configured to measure a parameter related to the vacuum fume flow. The automatic flow control assembly further includes a flow regulation device configured to regulate an ambient air flow introduced into the vacuum fume flow. In addition, the automatic flow control assembly includes control circuitry configured to control the flow regulation device based at least in part on the measured parameter related to the vacuum fume flow.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from and the benefit of U.S. Provisional Application Ser. No. 61/643,071, entitled “AUTOMATIC FLOW REGULATOR FOR FUME GUN,” filed May 4, 2012, which is hereby incorporated by reference in its entirety for all purposes. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to welding guns and, more particularly, to an automatic flow regulator for use in a welding fume gun. 
         [0003]    During a welding process, fumes and other particulates are introduced into the work environment that can be undesirable to the workplace environment. For example, in welding processes that utilize shielding gas, it is important that the shielding gas envelopes the weld in order to get a good weld. In order to remove the fumes and particulates that are generated during the welding process, a suction device may be added to the process. Such welding guns are often referred to as fume guns (i.e., welding torches with integrated fume removal features). However, conventional fume guns typically do not offer vacuum flow regulation to enable optimal vacuum flow. Rather, conventional vacuum systems used with fume guns often operate at only one setting (or a limited number of discrete settings). 
       BRIEF DESCRIPTION 
       [0004]    In one embodiment, an automatic flow control assembly includes a vacuum system configured to suction a vacuum fume flow through an internal passage of a welding fume gun. The automatic flow control assembly also includes a sensor configured to measure a parameter related to the vacuum fume flow. The automatic flow control assembly further includes a flow regulation device configured to regulate an ambient air flow introduced into the vacuum fume flow. In addition, the automatic flow control assembly includes control circuitry configured to control the flow regulation device based at least in part on the measured parameter related to the vacuum fume flow. 
         [0005]    In another embodiment, a method includes measuring a parameter related to a vacuum fume flow suctioned from a welding fume gun by a vacuum system. The method also includes regulating an ambient air flow introduced into the vacuum fume flow based at least in part on the measured parameter related to the vacuum fume flow. 
         [0006]    In another embodiment, an automatic flow control assembly includes a welding fume gun, which includes an internal passage configured to facilitate suctioning of welding fumes from a welding workpiece. The automatic flow control assembly also includes a vacuum and weld cable assembly that connects the welding fume gun to a welding system. In addition, the automatic flow control assembly includes a vacuum system assembly connected to the vacuum and weld cable assembly. The vacuum system assembly includes a vacuum system configured to generate a vacuum to suction the welding fumes through the internal passage of the welding fume gun, the vacuum and weld cable assembly, and a vacuum transfer tube of the vacuum system assembly. The vacuum transfer tube connects the vacuum and weld cable assembly to the vacuum system. The vacuum system assembly also includes a pitot tube sensor at least partially disposed in the vacuum transfer tube. The pitot tube sensor is configured to measure a pressure differential associated with a flow of the welding fumes through the vacuum transfer tube. The vacuum system assembly further includes a butterfly valve actuated by a servo motor. The butterfly valve and the servo motor are disposed in an ambient air flow line adjacent the vacuum transfer tube. The butterfly valve is configured to regulate a flow of ambient air into the flow of welding fumes through the vacuum transfer tube. In addition, the vacuum system assembly includes control circuitry configured to control actuation of the servo motor based at least in part on the pressure differential measured by the pitot tube sensor. 
     
    
     
       DRAWINGS 
         [0007]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0008]      FIG. 1  is a schematic diagram of an embodiment of an automatic flow control assembly in accordance with aspects of the present disclosure; 
           [0009]      FIG. 2  is a cross-sectional side view of an embodiment of the automatic flow control assembly in accordance with aspects of the present disclosure; 
           [0010]      FIG. 3  is a side view of an embodiment of the automatic flow control assembly in accordance with aspects of the present disclosure; 
           [0011]      FIG. 4  is a side view of an embodiment of the automatic flow control assembly in accordance with aspects of the present disclosure; and 
           [0012]      FIG. 5  is a perspective view of an embodiment of the automatic flow control assembly in accordance with aspects of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The embodiments described herein include a fume gun and associated vacuum system that enable optimized vacuum flow to remove fumes and other particulates from a welding process. As such, the embodiments described herein provide a minimal amount of vacuum as to not waste energy, but still maintain acceptable smoke capture efficiency. Further, the embodiments described herein provide a minimal amount of vacuum as to not interfere with the shielding gas flow and/or the weld puddle. In particular, the vacuum flow may be maintained at a target setpoint regardless of upstream changes (e.g., filter clogging, system load changes such as fume guns being added or removed, vacuum tubing restriction changes such as kinks, and so forth). Therefore, the embodiments described herein achieve automatic regulation of vacuum flow for a fume gun to provide optimal vacuum flow. 
         [0014]    In order to ensure that the shielding gas and/or the weld puddle is not disturbed, the vacuum flow level is maintained below a maximum level Q max , which will be different depending on the shielding gas flow, welding parameters, environmental factors, and so forth. However, in order to achieve an acceptable capture efficiency, the vacuum flow is maintained above a minimum level Q min . Therefore, the maximum and minimum levels Qmax and Qmin of the vacuum flow form an acceptable window of operation, which the embodiments described herein are capable of automatically maintaining without intervention from an operator. Conversely, as discussed above, conventional fume guns include vacuum systems that are typically oversized (i.e., that provide too much vacuum flow) and, as such, do not provide optimal vacuum flow. 
         [0015]    In general, the embodiments described herein provide a bypass upstream of the fume gun, which is used to adjust the vacuum flow from the fume gun. In particular, the vacuum flow from the fume gun is measured and automatically (electronically or mechanically) adjusted with a variable valve (requiring little to no input from the operator). The variable valve bleeds air into the vacuum system at an appropriate flow rate such that the vacuum system can continue to operate at the same vacuum rate, while the vacuum rate from the fume gun is adjusted. As such, the embodiments described herein generally include multiple components, namely, a measurement system that measures the vacuum flow from the fume gun, and a flow control system that regulates the vacuum flow from the automatic flow control assembly (e.g., that includes the vacuum system). 
         [0016]    Turning now to the figures,  FIG. 1  is a schematic diagram of an embodiment of an automatic flow control assembly  10  in accordance with aspects of the present disclosure. As illustrated, the automatic flow control assembly  10  is connected to a fume gun  12  (e.g., a welding torch) attached to a vacuum and weld cable assembly  14  (e.g., including a tube disposed around a weld cable  32 ). In turn, the vacuum and weld cable assembly  14  is attached to a vacuum transfer attachment  16  (e.g., a T-junction) that connects the fume gun  12  to a vacuum system assembly  18 , which includes a vacuum transfer tube  20  and a vacuum system  22 . In addition, the vacuum and weld cable assembly  14  and/or the vacuum transfer attachment  16  are attached to a power pin  24  that connects the fume gun  12  to a welding system (e.g., a welding power source and/or welding wire feeder, and so forth), which supplies the fume gun  12  with welding supplies, such as electrical current, shielding gas, welding wire, and so forth, depending on the particular needs of the welding process being performed using the fume gun  12 . 
         [0017]    As described in greater detail below, the vacuum transfer attachment  16  includes a vacuum flow passage  26  configured to route a vacuum flow from a vacuum flow passage  28  of the vacuum and weld cable assembly  14  into the vacuum transfer tube  20 . In certain embodiments, the vacuum flow passages  26 ,  28  of the vacuum transfer attachment  16  and the vacuum and weld cable assembly  14  are generally mating concentric tubular passages that surround a central passage  30  of the vacuum transfer attachment  16  and a weld cable  32  through the vacuum and weld cable assembly  14 , respectively. The weld cable  32  facilitates the electrical current, shielding gas, welding wire, and so forth, to flow from the welding system to the fume gun  12 . In general, the vacuum system  22  provides the vacuum that induces (e.g., suctions) the vacuum flow from the fume gun  12  through the vacuum flow passages  26 ,  28 . 
         [0018]    As also described in greater detail below, each of one or more sensors  34 ,  36 ,  38 ,  40  measures one or more parameters of the vacuum flow (e.g., pressure, pressure differential, flow rate, and so forth), and one or more automatic flow regulators  42 ,  44 ,  46  adjust the vacuum flow based on the measured vacuum flow parameters and, in certain embodiments, based on welding settings and/or real-time parameters such as welding process type (e.g., metal inert gas (MIG), tungsten inert gas (TIG), and so forth), voltage, current, wire feed speed, wire diameter, workpiece material thickness, and so forth, associated with the fume gun  12 . Although illustrated in  FIG. 1  as having four sensors  34 ,  36 ,  38 ,  40  and three automatic flow regulators  42 ,  44 ,  46 , the automatic flow control assembly  10  may include any number of sensors and automatic flow regulators. In certain embodiments (e.g., the embodiments illustrated in  FIGS. 2-5 ), the automatic flow control assembly  10  may include only one sensor and one automatic flow regulator. In certain embodiments, regardless of the numbers of sensors and automatic flow regulators used, the automatic flow regulators are located upstream of the sensors. 
         [0019]    As used herein, the term “upstream” is generally intended to mean closer to the vacuum system  22  than to the fume gun  12  along the vacuum flow path from the fume gun  12 , the vacuum and weld cable assembly  14 , the vacuum transfer attachment  16 , the vacuum transfer tube  20 , and the vacuum system  22 . Conversely, the term “downstream” is generally intended to mean closer to the fume gun  12  than to the vacuum system  22  along the vacuum flow path from the fume gun  12 , the vacuum and weld cable assembly  14 , the vacuum transfer attachment  16 , the vacuum transfer tube  20 , and the vacuum system  22 . 
         [0020]    As illustrated in  FIG. 1 , the sensors  34 ,  36 ,  38 ,  40  and automatic flow regulators  42 ,  44 ,  46  may be located at any number of locations in the automatic flow control assembly  10 . For example, in certain embodiments, a sensor  34  may be located in a handle  48  of the fume gun  12 , for example, at a downstream location (e.g., adjacent a neck  50  of the fume gun  12 ) of the handle  48 . In certain embodiments, the vacuum and weld cable assembly  14  may include a diameter increase  52  upstream of the handle  48  of the fume gun  12 . In certain embodiments, a sensor  36  may be located near the diameter increase  52  (e.g., at a location proximate to, and downstream from, the diameter increase  52 ) of the vacuum and weld cable assembly  14 . In certain embodiments, a sensor  38  may be located near where the vacuum transfer attachment  16  connects to the vacuum transfer tube  20  (e.g., either in the vacuum transfer attachment  16  proximate to the vacuum transfer tube  20 , or in the vacuum transfer tube  20  proximate to the vacuum transfer attachment  16 ). In certain embodiments, a sensor  40  may be located in the vacuum transfer tube  20  proximate to the vacuum system  22 . 
         [0021]    In addition, in certain embodiments, an automatic flow regulator  42  may be located near the diameter increase  52  (e.g., at a location proximate to, and upstream from, the diameter increase  52 ) of the vacuum and weld cable assembly  14 . In certain embodiments, an automatic flow regulator  44  may be located in the vacuum transfer tube  20  (e.g., at a downstream location of the vacuum transfer tube  20  proximate to the vacuum transfer attachment  16 ). In certain embodiments, an automatic flow regulator  46  may be located near where the vacuum transfer tube  20  connects to the vacuum system  22 . The automatic flow regulators  42 ,  44 ,  46  function as bypasses, which allow or block a flow of ambient air into the vacuum flow, thereby adjusting the vacuum flow from the fume gun  12  while maintaining the vacuum flow through the vacuum system  22  relatively constant. As such, the embodiments described herein may be retrofit into existing vacuum systems that operate at only one setting (or a limited number of discrete settings). 
         [0022]    As described above, in certain embodiments, the automatic flow control assembly  10  may include only one sensor and only one automatic flow regulator. For example,  FIGS. 2-5  are various illustrations of embodiments of the automatic flow control assembly  10  having one sensor  48  and one automatic flow regulator  50 . In particular, both the sensor  48  and the automatic flow regulator  50  illustrated in  FIGS. 2-5  are located in the vacuum transfer tube  20 . More specifically, the sensor  48  is located in the vacuum transfer tube  20  between the vacuum transfer attachment  16  and the automatic flow regulator  50 , and the automatic flow regulator  50  is located in the vacuum transfer tube  20  between the sensor  48  and the vacuum system  22 . It should be noted that the sensor  48  illustrated in  FIGS. 2-5  and the sensors  34 ,  36 ,  38 ,  40  illustrated in  FIG. 1  are intended to be substantially similar, and the automatic flow regulator  50  illustrated in  FIGS. 2-5  and the automatic flow regulators  42 ,  44 ,  46  illustrated in  FIG. 1  are intended to be substantially similar. 
         [0023]    Locating the sensor  48  and the automatic flow regulator  50  in the vacuum transfer tube  20  provides several tangible benefits. For example, locating the sensor  48  in the vacuum transfer tube  20  ensures that the sensor  48  is relatively close to a source of power (e.g., the vacuum system  22 , the welding system to which the weld cable  32  is attached, and so forth). In addition, locating the sensor  48  in the vacuum transfer tube  20  ensures that the sensor  48  remains relatively static, as opposed to being located closer to the fume gun  12 , which is often moved around in order to facilitate welding operations. As such, the sensor  48  is moved around relatively little, thereby enhancing the accuracy of the sensor  48  (e.g., reducing or even eliminating noise in the sensor  48  that may result from excessive movement) and enhancing the durability of the automatic flow control assembly  10 . Furthermore, locating the sensor  48  in the vacuum transfer tube  20 , and not in the fume gun  12  or the vacuum and weld cable assembly  14 , does not add weight to the fume gun  12  or the vacuum and weld cable assembly  14 . 
         [0024]    In addition, locating the automatic flow regulator  50  in the vacuum transfer tube  20  improves the effectiveness of the automatic flow regulator  50  insofar as the vacuum transfer tube  20  has the correct high transfer velocity. Furthermore, the vacuum transfer tube  20  is generally not near the work floor and, as such, locating the automatic flow regulator  50  in the vacuum transfer tube  20  minimizes the amount of debris sucked in through the automatic flow regulator  50 . Moreover, the automatic flow regulator  50  may be more easily oriented in a direction so as to minimize the suction of unwanted debris through the automatic flow regulator  50 . 
         [0025]      FIG. 2  is a cross-sectional side view of an embodiment of the automatic flow control assembly  10  in accordance with aspects of the present disclosure. As illustrated, in certain embodiments, the sensor  48  may include a pitot tube, which may be particularly appropriate for use in the fume gun assembly  10  insofar as pitot tubes are relatively cheap, accurate, and small. It will be understood that the pitot tube sensor  48  includes the pressure line illustrated in  FIGS. 2-5 , which connects the pitot tube dynamic pressure side to a differential sensor that, in certain embodiments, may be located on a control chip  52  (shown in  FIGS. 3 and 5 ). The pitot tube sensor  48  conveys a pressure differential to the control chip  52  on a circuit board assembly  54 . Based on the pressure differential measured by the pitot tube sensor  48 , the control chip  52  determines the corresponding vacuum flow rate (e.g., using calibration curves) through the vacuum transfer tube  20  upstream of a T-junction  56  at which the automatic flow regulator  50  connects to the vacuum transfer tube  20 . Based on this determined vacuum flow rate, the control chip  52  determines an appropriate opening position of a butterfly valve  58  of the automatic flow regulator  50  that will allow a certain amount of ambient air  60  to enter the vacuum transfer tube  20  through the automatic flow regulator  50 . In particular, in certain embodiments, the control chip  52  sends a signal to a servo motor  62  (shown in  FIGS. 3 and 5 ) to cause the butterfly valve  58  to be rotated into an appropriate opening position to allow a specific amount of ambient air  60  into the vacuum transfer tube  20  such that an amount of vacuum flow  64  from the fume gun  12  is either increased or decreased, without modifying an amount of vacuum flow  66  generated by the vacuum system  22 . 
         [0026]    In certain embodiments, automatically controlling the automatic flow regulator  50  in this manner may ensure that a relatively constant vacuum flow  64  from the fume gun  12  is maintained, and that the amount of vacuum flow  64  from the fume gun  12  is lower than the amount of vacuum flow  66  suctioned into the vacuum system  22 . In addition, in certain embodiments, the control chip  52  may control the automatic flow regulator  50  such that the amount of vacuum flow  64  from the fume gun  12  is automatically adjusted to account for certain welding settings and/or real-time parameters such as welding process type (e.g., metal inert gas (MIG), tungsten inert gas (TIG), and so forth), voltage, current, wire feed speed, wire diameter, workpiece material thickness, and so forth, associated with the fume gun  12 . 
         [0027]    Although illustrated in  FIGS. 2-5  as being a pitot tube sensor, in other embodiments, the sensor  48  may be any suitable type of sensor capable of determining a vacuum flow rate in the fume gun  12 , the vacuum and weld cable assembly  14 , the vacuum transfer attachment  16 , the vacuum transfer tube  20 , the vacuum system  22 , or any other component of the automatic flow control assembly  10 . For example, in certain embodiments, the sensor  48  may measure calibrated pressure differential in the handle  48  of the fume gun  12 . In other embodiments, the sensor  48  may be any one of the following: a rotameter, a hotwire anemometer, a mechanical flow meter (e.g. a piston meter, a rotary piston, a turbine flow meter, a Pelton wheel, and so forth), a pressure-based meter (e.g. a pitot tube, a Venturi meter, a multi-hole pressure probe, and so forth), an optical flow meter, a thermal mass flow meter, a vortex flow meter, an electromagnetic flow meter, an ultrasonic flow meter, a coriolis flow meter, or a combination thereof. 
         [0028]    In addition, although illustrated in  FIGS. 2 and 5  as being a butterfly valve  58 , in other embodiments, the mechanism for adjusting the flow of ambient air  60  through the automatic flow regulator  50  may be any suitable mechanism capable of being actuated to ensure than an appropriate amount of ambient air  60  enters the vacuum system assembly  18  and mixes with the vacuum flow. For example, in certain embodiments, the mechanism for adjusting the flow of ambient air  60  through the automatic flow regulator  50  may be a gate valve, a ball valve, a needle valve, and so forth. 
         [0029]    In certain embodiments, the control chip  52  may include a processor and memory for performing the necessary calculations related to determining the vacuum flow rate, and determining an appropriate amount of ambient air  60  to be allowed into the vacuum system assembly  18 , and for sending signals to the servo motor  62  (or other suitable actuation mechanism) for actuating the butterfly valve  58  (or other flow regulation device) such that the appropriate amount of ambient air  60  enters the vacuum system assembly  18  and mixes with the vacuum flow. The power required to power the control chip  52 , the servo motor  62 , and other components of the vacuum system assembly  18  that require power may be supplied from any number of suitable power sources. For example, in certain embodiments, this power may be supplied by a welding wire feeder from which the fume gun  12  receives welding wire, by the vacuum system  22 , by an external source (e.g., from a power outlet), or may be internally generated within the automatic flow control assembly  10  (e.g., using a turbine). 
         [0030]    The automatic flow control assembly  10  described herein provides several tangible benefits as compared to conventional fume gun assemblies. First, components of the automatic flow control assembly  10  may be easily retrofit into pre-existing fume gun assemblies. For example, in certain situations, it may be possible to simply replace a pre-existing vacuum transfer tube with the vacuum transfer tube  20  described herein (e.g., including the sensor  48 , the automatic flow regulator  50 , the circuit board assembly  54 , and other components directly connected to the vacuum transfer tube  20 ). More specifically, as described above, the vacuum system  22  may be any type of vacuum system, including those capable of operating at only one setting (or a limited number of discrete settings), with the sensor  48 , control chip  52 , and automatic flow regulator  50  automatically adjusting the vacuum flow rate suctioned from the fume gun  12 . 
         [0031]    In addition, the automatic flow control assembly  10  described herein improves the quality of the weld while capturing a high amount of fumes. Furthermore, the automatic flow control assembly  10  described herein has a very low chance of overheating, as opposed to conventional fume gun assemblies. Moreover, the automatic flow control assembly  10  described herein is capable of automatically adjusting the vacuum flow rate such that little to no input is required by the operator of the automatic flow control assembly  10 . More specifically, the automatic flow control assembly  10  takes a flow or pressure measurement and, through electronic controls and processing, adjusts a variable valve that bleeds ambient air into the vacuum system assembly  18 . As such, the automatic flow control assembly  10  may be capable of adjusting the vacuum flow rate from the fume gun  12  to any value from zero to the maximum vacuum flow rate that may be suctioned by the vacuum system  22 . 
         [0032]    As described above, the automatic flow control assembly  10  is configured to adjust the vacuum flow rate suctioned through the fume gun  12  to be less than the vacuum flow rate that the vacuum system  22  is configured to suction. The fume gun  12  is configured to suction weld fumes and other particulates from the weld puddle area to a remote vacuum extraction device (e.g., the vacuum system  22 ). In certain embodiments, the fume gun  12  is capable of suctioning less than approximately 20 cubic feet per minute (cfm) of air, weld fumes, and other particulates, as opposed to conventional fume guns, which typically suction greater than approximately 30 cfm of air, weld fumes, and other particulates. In other words, the fume gun  12  facilitates the use of less powerful vacuum systems, and enables the capture of air, weld fumes, and other particulates with less disruption to the weld shielding gas. 
         [0033]    In certain embodiments, the cross-sectional area of the vacuum flow passage  28  may be less than approximately 0.38 square inches at a location where the fume gun  12  abuts the vacuum and weld cable assembly  14 , as opposed to conventional vacuum flow cables, which may have cross-sectional vacuum areas of 1.1 square inches (or even greater). As such, the vacuum and weld cable assembly  14  may be much smaller than conventional vacuum flow cables. Therefore, the vacuum and weld cable assembly  14  will also be generally lighter and more flexible than conventional vacuum flow cables, thereby reducing the overall cost and enhancing the usability of the vacuum and weld cable assembly  14  and, indeed, the system as a whole. 
         [0034]    While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.