Abstract:
An enclosure for natural gas wellheads includes a fixed enclosure portion and a removable enclosure portion. The removable enclosure portion facilitates access to the wellhead, while the fixed enclosure portion protects the wellhead&#39;s computer and meter systems. The enclosure provides ventilation to prevent accumulation of natural gas within the enclosure in the event of a leak, and electrical grounding to prevent static electricity discharges in the presence of natural gas.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is an enclosure for natural gas wellheads, providing protection, ease of access to the wellhead components, electrical grounding, and ventilation to prevent danger in the event of leaks. 
     2. Description of the Related Art 
     Natural gas wellheads are frequently enclosed by either fiberglass enclosures that must be lifted off the wellhead to gain access to the various components, or with make-shift plywood structures. Such enclosures not only impede access to the wellhead, but may also fail to provide proper ventilation to permit natural gas to exit the enclosure in the event of a leak, and also fail to provide electrical grounding to prevent static electricity sparks in the presence of natural gas. 
     Various housings for wellheads have been proposed in an attempt to overcome some of these disadvantages. For example, U.S. Pat. No. 4,335,740, issued to J. W. Boley on Jun. 22, 1982, describes an underground wellhead bunker. Such an underground bunker does not provide the ease of access to the wellhead components that removal of a portion of the housing can provide. 
     U.S. Pat. No. 5,960,592, issued to P. F. Lilienthal, II, et al. on Oct. 5, 1999, describes a protective enclosure for outdoor equipment. The enclosure includes a plurality of hollow panels, which are assembled, and possibly filled, at the site of the equipment. The equipment is then installed within the cabinet. This enclosure fails to provide ease of installation over pre-existing equipment, and means for accessing and servicing this equipment. 
     U.S. Pat. No. 6,176,046, issued to T. G. Quine et al. on Jan. 23, 2001, describes a portable, pre-manufactured, modular natural gas delivery station. The delivery station will typically be a modular building including a gas metering and regulating room, an odorant room, a boiler room, an energy generation room, and an electrical and control room. These rooms will typically contain gas piping with a gas inlet and outlet, a metering unit, a heat exchanger, a natural gas-powered generator, and a control unit. The building described by this patent has no features to facilitate removal of a portion of the building for access to the equipment, for example, to perform additional drilling. 
     Examples of other enclosures include U.S. Pat. No. 5,331,778, issued to A. Mazpule et al. on Jul. 26, 1994, describing a portable enclosure; U.S. Pat. No. 5,921,043, issued to H. C. McDonald, on Jul. 13, 1999, describing a pre-fabricated enclosed building; U.S. Pat. No. 6,009,673, issued to E. D. Adams on Jan. 4, 2000, describing a modular hunting blind; U.S. Pat. No. 6,058,660, issued to W. F. Melton on May 9, 2000, describing a portable garage; U.S. Pat. No. 6,102,230, issued to S. Gould on Aug. 15, 2000, describing an enclosure system; and European Pat. Application 0,481,246 published Apr. 22, 1992, describing a public laboratory. 
     Accordingly, an enclosure for natural gas wellheads having various doors dimensioned and configured to permit access to the wellhead, removable enclosure portions to facilitate access to larger portions of the wellhead, ventilation, and electrical grounding is desired. 
     SUMMARY OF THE INVENTION 
     The present invention is an enclosure for natural gas wellheads having a fixed portion dimensioned and configured to be entered by a person, and a removable portion dimensioned and configured to enclose the wellhead itself. 
     The enclosure of the present invention is mounted on a base frame, with the fixed portion including a floor. The frame includes a channel on each side, dimensioned and configured to receive the sides of the removable portion, and a plurality of clamps dimensioned and configured to secure the removable portion to the frame. The removable enclosure portion includes a hatch dimensioned and configured to provide access to the wellhead, and a plurality of handles to facilitate removal and installation of the removable portion. 
     The fixed enclosure portion contains the total flow computer, the V-cone measurement meter, the water turbine measurement meter, and a building vent. The gas and water pipelines extending upward from the ground at the wellhead continue into the fixed portion of the enclosure, proceeding through the meters and onward to storage and/or distribution systems as is well-known in the art of natural gas extraction. An opening defined in one side of the fixed enclosure portion communicates with one end of the removable enclosure portion. The floor of the fixed enclosure portion includes a hole dimensioned and configured to permit the gas and water pipes to reenter the ground. The fixed enclosure portion also includes one or more vents to permit natural gas to exit the fixed enclosure portion, preventing build-up of natural gas within the enclosure if a leak should occur. Additionally, the enclosure includes grounding lugs dimensioned and configured to provide for the discharge of static electricity, thereby preventing electrical sparks from occurring in close proximity to the natural gas. 
     The wellhead enclosure of the present invention offers several advantages over presently known enclosures. The removable portion covering the wellhead itself permits performing simple operations, for example, cleaning strainers, or checking to ensure that the wellhead is working properly, by merely opening the hatch. More difficult operations, for example, redrilling the well, drilling the well to a deeper depth, or checking the water pump located within the well, are facilitated by removal of the removable enclosure portion. The total flow computer and meters are provided with the best possible protection from outside weather conditions and unauthorized tampering by their location within the fixed enclosure portion. 
     It is therefore an aspect of the present invention to provide a natural gas wellhead enclosure having a fixed portion dimensioned and configured to protect peripheral devices, and a removable enclosure portion dimensioned and configured to protect the wellhead itself. 
     It is another aspect of the present invention to provide a natural gas wellhead enclosure having means for ventilating the enclosure, thereby preventing build-up of natural gas within the enclosure in the event of a leak. 
     It is a further aspect of the present invention to provide a natural gas wellhead enclosure having electrical grounding, preventing static electricity discharges in the presence of natural gas. 
     These and other aspects of the invention will become apparent through the following description and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front isometric view of a natural gas wellhead enclosure according to the present invention, illustrating the removable enclosure portion attached to the fixed enclosure portion. 
     FIG. 2 is a rear isometric view of a natural gas wellhead enclosure according to the present invention, illustrating the removable enclosure portion removed. 
     FIG. 3 is a front isometric view of the frame for a natural gas wellhead enclosure according to the present invention. 
     FIG. 4 is an isometric view of a clamp for securing the removable enclosure portion of a natural gas wellhead enclosure according to the present invention to its support frame. 
     FIG. 5 is a front view of a grounding lug for a natural gas wellhead enclosure according to the present invention. 
     FIG. 6 is an end view of one of the two unistruts that may be utilized to secure peripheral devices to a natural gas wellhead enclosure according to the present invention. 
    
    
     Like reference numbers denote like elements throughout the drawings. 
     DETAILED DESCRIPTION 
     The present invention is an improved enclosure for natural gas wellheads. 
     Referring to FIGS. 1 and 2, the wellhead enclosure  10  includes a fixed enclosure portion  12 , and a removable enclosure portion  14 . The fixed enclosure portion  12  includes a floor  16 , a front  18 , a pair of sides  20 ,  22 , a back  24 , and a ceiling  26 . The front  18 , sides  20 ,  22 , and back  24 , which may be made out of a strong, rigid material, for example, steel, and may include insulation, for example, foil insulation, on their inner surfaces. A door  28  is provided to permit a person to enter the enclosure  12 . Referring to FIG. 3, the fixed enclosure  12  also defines an opening  30 , dimensioned and configured to communicate with the removable enclosure portion  14 . The opening  30  may be surrounded by a guide lip  32 , dimensioned and configured to fit just inside and/or abut the open end  34  of the removable enclosure  14 . The door  28  and opening  30  may be located on any of the front  18 , side  20 , side  22 , or back  24  of the fixed enclosure portion  12 , provided that the door  28  and opening  30  should not be located on the same panel  18 ,  20 ,  22 ,  24 , and the opening  30  should correspond to the portion of the support frame  36  extending under the removable enclosure portion  14 . The fixed enclosure portion  12  may also include a pair of unistruts  38  (FIGS. 2,  6 ), dimensioned and configured to secure peripheral devices, for example, the driver  40  and circuit breaker  42 . The floor  16  defines an opening  44 , dimensioned and configured to permit piping to enter the ground. The fixed enclosure portion  12  also includes one or more vents  46 ,  48 . 
     The support frame  36 , best illustrated in FIG. 3, supports the entire enclosure  10 , extending underneath both the fixed enclosure portion  12  and removable enclosure portion  14 . The support frame  36  preferably includes a pair of main beams  47 , connected by a plurality of cross beams  49 . The main beams  47  may include a guide lip  50 , dimensioned and configured to fit within and/or abut the inside of the bottom  52  of the removable enclosure portion  14 . The frame  36  may also include reinforcement plates, and electrical grounding lugs  56  (FIG.  5 ). A plurality of pipe support members  58  may extend upward from the frame  36 . 
     Referring back to FIGS. 1 and 2, the removable enclosure portion  14  includes a front  60 , a back  62 , a top  64 , and one end  66 , which are preferably made from a strong, rigid material, for example, steel. The end  34  opposite the end  66  is open, providing for communication between the fixed enclosure portion  12  and removable enclosure portion  14  through the opening  30 . The removable enclosure portion  14  includes at least one hatch  68 , dimensioned and configured to permit access to the interior of the enclosure  14 . In the present example, the hatch  68  is illustrated as being defined within the front panel  60 . Alternative embodiments could include the hatch  68 , or additional hatches within the end panel  66 , top panel  64 , or back panel  62 . 
     The removable enclosure portion  14  is secured to the support frame  36  on which it sits by a plurality of clamps  70 , best illustrated in FIG.  4 . One example of a preferred clamp includes a longitudinal member  72 , pivotally secured to a main beam  47 , and having a handle  74  at its upper end. A catch  76  secured to either the front  60  or back  62  of the removable enclosure portion  14 , is dimensioned and configured to mate with a channel  78  defined around the circumference of the elongated member  72 . The removable enclosure portion  14  preferably also includes a plurality of handles  80 , which in the illustrated example are located on the front  60 , back  62 , and end  66 . 
     In use, the removable enclosure portion  14  will cover the wellhead  82 , and the fixed enclosure portion  12  will enclose the wellhead peripherals  84 . If a gas leak should occur, natural gas will exit the enclosure  10  through the vents  46 ,  48 , instead of building up within the enclosure  10 . A person wishing to check the total flow computer, V-cone measurement meter, water turbine measurement meter, or peripheral devices  84 , may open the door  28 , and enter the fixed enclosure portion  12  to do so. Likewise, a person wishing to clean the strainer or verify proper operation of the wellhead may open the hatch  68  to do so. If more extensive work on the wellhead  82  is desired, for example, redrilling the well, drilling the well to a deeper depth, or checking the water pump within the well, the removable portion  14  may be removed. Preferably, the removable portion  14  weighs less than approximately 200 lb., so that it can be removed by one or two people. First, the clamps  70  are unclamped. Second, the removable enclosure  14  is raised and carried, or dragged, from the position illustrated in FIG. 1 wherein it is on top of the support frame, to the position illustrated in FIG. 2, wherein it is substantially removed from the support frame  36 . A pair of individuals may completely lift the removable enclosure portion  14  off of the support frame  36  or the ground utilizing the handles  80  on the front  60  and back  62 . Alternatively, a single individual may drag the removable enclosure portion  14  off of the support frame  36 , and return it to its position on the support frame  36 , utilizing the handles  80  on the end  66 . 
     While a specific embodiment of the invention has been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.