Patent Publication Number: US-11655763-B1

Title: Direct drive unit removal system and associated methods

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Non-Provisional application Ser. No. 17/936,885, filed Sep. 30, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” which is a continuation of U.S. Non-Provisional application Ser. No. 17/883,693, filed Aug. 9, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,512,642, issued Nov. 29, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/808,792, filed Jun. 24, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,473,503, issued Oct. 18, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/720,390, filed Apr. 14, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,401,865, issued Aug. 2, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/671,734, filed Feb. 15, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,346,280, issued May 31, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/204,338, filed Mar. 17, 2021, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,319,878, issued May 3, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/154,601, filed Jan. 21, 2021, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,982,596, issued Apr. 20, 2021, which is a divisional of U.S. Non-Provisional application Ser. No. 17/122,433, filed Dec. 15, 2020, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,961,912, issued Mar. 30, 2021, which is a divisional of U.S. Non-Provisional application Ser. No. 15/929,924, filed May 29, 2020, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,895,202, issued Jan. 19, 2021, which claims the benefit of and priority to U.S. Provisional Application No. 62/899,975, filed Sep. 13, 2019, titled “TURBINE REMOVAL SYSTEM,” the entire disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     This disclosure relates to embodiments of systems and methods for the removal and/or positioning of a direct drive unit housed in an enclosure, such as a direct drive turbine (DDT) when connected to a gearbox for driving a driveshaft, which, in turn, may be connected to a pump such as for use in a hydraulic fracturing system. 
     Traditional fracturing pumping fleets have had fuel supplied from a single fuel source. In such units, when a unit runs low on fuel (for example diesel), that unit is shutdown while another stand by unit is brought in, refueled, and then put into service. Some inefficiencies included in this process are that the unit once low on primary fuel must be stopped, refueled while another unit is simultaneously being introduced into its place to make up for the loss of the pumping power that the unit provides. This may affect the pumping performance during a section as well as requiring human intervention to perform the refueling, lining up suction and discharge valves. This may require multiple personnel to relay back the information so the process is performed in the correct series of steps. Using a single fuel source also limits the ability for the fracturing fleet to make it continuously through a section when low on fuel which results in delays in pumping completion. 
     In addition, in cases where the unit needs to be taken offline for maintenance or replacement, significant disassembly is required to remove the unit from its enclosure and to install a replacement unit, potentially resulting in excessive downtime. In some cases, the entire trailer and enclosure need to be removed from the site so a new, fully equipped trailer may be moved into place. 
     Accordingly, it may be seen that a need exists for more efficient ways of accessing the drive units for maintenance purposes and/or replacement with minimum disruption to the system operations and the surrounding equipment. The present disclosure addresses these and other related and unrelated problems in the art. 
     SUMMARY OF THE DISCLOSURE 
     According to one embodiment of the disclosure, a method of removing a direct drive unit (DDU) housed in an enclosure. The DDU includes a gearbox and a turbine engine connected to the gearbox for driving a driveshaft connected to a pump for use in high-pressure, high-power hydraulic fracturing operations. The method may include accessing the enclosure. The enclosure contains air inlet ducting connected to the turbine engine and air exhaust ducting connected to the turbine engine. The method may further include disconnecting the turbine engine from the air inlet ducting, disconnecting the turbine engine from at least one fuel line, disconnecting the gearbox from the driveshaft, disconnecting the turbine engine from at least one exhaust flange connected to the air exhaust ducting, and operating a DDU positioner assembly to position the DDU for withdrawal from the enclosure, and removing the DDU from the enclosure. 
     According to another embodiment of the disclosure, a direct drive unit (DDU) positioner assembly is disclosed for positioning a DDU housed in an enclosure for removal from the enclosure. The DDU includes a gearbox and a turbine engine connected to the gearbox for driving a driveshaft connected to a pump for use in high-pressure, high-power hydraulic fracturing operations. The DDU positioner assembly may include a plurality of longitudinal rails extending in a longitudinal direction along the central axis of the DDU and a plurality of lateral rails extending in a lateral direction transverse to the longitudinal direction. The DDU positioner assembly may further include a platform slidably connected to the plurality of lateral rails. The plurality of longitudinal rails may be mounted on the platform and the DDU may be slidably connected to the longitudinal rails. The DDU may be movable in the longitudinal direction along the longitudinal rails and the platform may be movable in the lateral direction along the lateral rails. 
     According to yet another embodiment of the disclosure, a direct drive unit (DDU) positioner assembly is disclosed for positioning a DDU housed in an enclosure for removal from the enclosure. The DDU includes a gearbox and a turbine engine connected to the gearbox for driving a driveshaft connected to a pump for use in high-pressure, high-power, hydraulic fracturing operations. The DDU positioner assembly may include a platform connected to a support of the gearbox and mounted on an enclosure base of the enclosure. The enclosure base may have a plurality of lubrication grooves for facilitating sliding movement of the platform relative to the enclosure base. The DDU positioner assembly may include a lubricator to convey lubricant to the lubrication grooves. The platform may be fixedly attached to the enclosure base by one or more fasteners during operation of the DDU and in slidable engagement with the enclosure base upon removal of the one or more fasteners. 
     Those skilled in the art will appreciate the benefits of various additional embodiments reading the following detailed description of the embodiments with reference to the below-listed drawing figures. It is within the scope of the present disclosure that the above-discussed aspects be provided both individually and in various combinations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings may be expanded or reduced to more clearly illustrate the embodiments of the disclosure. 
         FIG.  1 A  is a schematic diagram of a pumping unit according to an embodiment of the disclosure. 
         FIG.  1 B  is a schematic diagram of a layout of a fluid pumping system according to an embodiment of the disclosure. 
         FIG.  2    is a perspective view of an enclosure for housing a direct drive unit (DDU) according to an embodiment of the disclosure. 
         FIG.  3    is a top plan view of the enclosure housing the DDU according to an embodiment of the disclosure. 
         FIG.  4    is a side elevation view of the DDU mounted on a DDU positioner assembly according to a first embodiment of the disclosure. 
         FIG.  5    is an end elevation view of the DDU of  FIG.  4    according to a first embodiment of the disclosure. 
         FIG.  6 A  is a perspective view of the DDU of  FIG.  4    in a first position according to a first embodiment of the disclosure. 
         FIG.  6 B  is a perspective view of the DDU of  FIG.  6 A  moved to a second position according to a first embodiment of the disclosure. 
         FIG.  6 C  is a perspective view of the DDU of  FIG.  6 B  moved to a third position according to a first embodiment of the disclosure. 
         FIG.  7    is a side elevation view of the DDU mounted on a DDU positioner assembly according to a second embodiment of the disclosure. 
         FIG.  8 A  is a perspective view of the DDU of  FIG.  7    in a first position according to a second embodiment of the disclosure. 
         FIG.  8 B  is a perspective view of the DDU of  FIG.  8 A  moved to a second position according to a second embodiment of the disclosure. 
         FIG.  8 C  is a perspective view of the DDU of  FIG.  8 B  moved to a third position according to a second embodiment of the disclosure. 
         FIG.  9    is an enlarged detail of a portion of the DDU positioner assembly according to a second embodiment of the disclosure. 
         FIG.  10    is a detail of a portion of the DDU positioner assembly according to a second embodiment. 
         FIG.  11    is a side elevation view of the DDU mounted on a DDU positioner assembly according to a third embodiment of the disclosure. 
         FIG.  12 A  is a perspective view of the DDU of  FIG.  11    in a first position according to a third embodiment of the disclosure. 
         FIG.  12 B  is a perspective view of the DDU of  FIG.  12 A  moved to a second position according to a third embodiment of the disclosure. 
         FIG.  12 C  is a perspective view of the DDU of  FIG.  12 B  moved to a third position according to a third embodiment of the disclosure. 
     
    
    
     Corresponding parts are designated by corresponding reference numbers throughout the drawings. 
     DETAILED DESCRIPTION 
     Generally, this disclosure is directed to a direct drive unit (DDU) positioner assembly, positioning system, removal system, and/or associated mechanisms that will allow a DDU including a gearbox and a turbine engine connected to the gearbox to be detached from surrounding equipment and removed through the side of an enclosure housing the direct drive unit. The system will allow for inspections, maintenance, or even a complete exchange of the direct drive unit with another if necessary. 
       FIG.  1 A  illustrates a schematic view of a pumping unit  11  for use in a high-pressure, high power, fluid pumping system  13  ( FIG.  1 B ) for use in hydraulic fracturing operations according to one embodiment of the disclosure.  FIG.  1 B  shows a typical pad layout of the pumping units  11  (indicated as FP 1 , FP 2 , FP 3 , FP 4 , FP 5 , FP 6 , FP 7 , FP 8 ) with the pumping units all operatively connected to a manifold M that is operatively connected to a wellhead W. By way of an example, the system  13  is a hydraulic fracturing application that may be sized to achieve a maximum rated horsepower of 24,000 HP for the pumping system  13 , including a quantity of eight (8) 3000 horsepower (HP) pumping units  11  that may be used in one embodiment of the disclosure. It will be understood that the fluid pumping system  13  may include associated service equipment such as hoses, connections, and assemblies, among other devices and tools. As shown in  FIG.  1   , each of the pumping units  11  are mounted on a trailer  15  for transport and positioning at the jobsite. Each pumping unit  11  includes an enclosure  21  that houses a direct drive unit (DDU)  23  including a gas turbine engine  25  operatively connected to a gearbox  27 . The pumping unit  11  has a driveshaft  31  operatively connected to the gearbox  27 . The pumping unit  11  includes a high-pressure, high-power, reciprocating positive displacement pump  33  that is operatively connected to the DDU  23  via the driveshaft  31 . In one embodiment, the pumping unit  11  is mounted on the trailer  15  adjacent the DDU  23 . The trailer  15  includes other associated components such as a turbine exhaust duct  35  operatively connected to the gas turbine engine  25 , air intake duct  37  operatively connected to the gas turbine, and other associated equipment hoses, connections, etc. to facilitate operation of the fluid pumping unit  11 . 
     In the illustrated embodiment, the gas turbine engine  25  is a Vericor Model TF50F bi-fuel turbine; however, the direct drive unit  23  may include other gas turbines or suitable drive units, systems, and/or mechanisms suitable for use as a hydraulic fracturing pump drive without departing from the disclosure. The gas turbine engine  25  is cantilever mounted to the gearbox  27  with the gearbox supported by the floor  41  of the enclosure  21 . The gearbox  27  may be a reduction helical gearbox that has a constant running power rating of 5500 SHP and intermittent power output of 5850 SHP, or other suitable gearbox. It should also be noted that, while the disclosure primarily describes the systems and mechanisms for use with direct drive units  23  to operate fracturing pumping units  33 , the disclosed systems and mechanisms may also be directed to other equipment within the well stimulation industry such as, for example, blenders, cementing units, power generators and related equipment, without departing from the scope of the disclosure. 
       FIG.  2    illustrates the enclosure  21  that houses the direct drive unit  23  in an interior space  46  of the enclosure. In one embodiment, the enclosure has access doors  45  for removal of the DDU  23  from the enclosure and/or other components within the enclosure. The enclosure  21  provides sound attenuation of the DDU  23  during operation. 
     As shown in  FIG.  3   , the direct drive unit  23  and the enclosure  21  has a longitudinal axis L 1  and a lateral axis L 2  transverse to the longitudinal axis.  FIG.  3    illustrates a top view of the enclosure  21  with the DDU  23  shown attached to the driveshaft  31  that extends through an opening  48  in a first longitudinal end  47  of the enclosure. An air exhaust assembly  35  extends through a second longitudinal end  49  of the enclosure. The DDU  23  has a central axis CL extending in the longitudinal direction L 1  that extends through the centerline of the unit and is aligned with the centerline of the driveshaft  31 . The gearbox  27  includes an outlet flange  50  that is connected to the driveshaft  31 . The gas turbine engine  25  has two air inlet ports  51 ,  53  on a respective lateral side of the central axis CL and an exhaust duct flange  54  that connects the gas turbine engine to the air exhaust assembly  35  at the longitudinal end  49  of the enclosure  21 . In one embodiment, the access doors  45  are mounted on a first lateral side  55  of the enclosure  21 , but the enclosure may have additional access doors on a second lateral side  57  of the enclosure, or the access doors may be positioned only on the second lateral side without departing from the scope of this disclosure. The gas turbine engine  25  may include polymer expansion joints  61 ,  63  connected to air inlet ports  51 ,  53 , to facilitate the removal of the gas turbine engine from the enclosure  21 . The gas turbine engine  25  may include various fuel lines, communication lines, hydraulic and pneumatic connections, and other connections or accessories needed for operation of the gas turbine engine without departing from the disclosure. Such connections may utilize quick disconnect fittings and check valves to facilitate disconnection of the gas turbine engine  25  during removal of the DDU  23  from the enclosure  21 . Further, such connections such as fuel lines and hydraulic lines may run to a single bulkhead (not shown) within or near the enclosure to allow for quick disconnection by locating these connections in a common location. 
       FIG.  4    is a side elevation view of the DDU  23  as viewed from the lateral side  55  of the enclosure  21 , with the DDU being mounted on a DDU positioner assembly or DDU positioning system  101  ( FIGS.  4 - 6 C ) for positioning the DDU for withdrawal or removal from the enclosure through the access doors  45 . In one embodiment, the DDU positioner assembly  101  comprises a platform  103  slidably mounted to overlie two lateral rails  105 ,  107  mounted to overlie the floor  41  of the enclosure  21  and extending laterally across the enclosure generally between the lateral sides  55 ,  57 . The DDU positioner assembly  101  comprises two longitudinal rails  109 ,  111  mounted to overlie the platform  103  and extending in the longitudinal direction L 1 . The DDU  23  is slidably mounted on the longitudinal rails  109 ,  111  for positioning the DDU in the longitudinal direction L 1 . In one embodiment, the DDU positioner assembly  101  includes lateral guide rollers  115 ,  117  mounted on a respective lateral rail  105 ,  107 , and longitudinal guide rollers  121 ,  123  mounted on a respective longitudinal rail  109 ,  111 . The platform  103  is connected to the lateral guide rollers  115 ,  117  to allow slidable movement and positioning of the DDU  23  mounted on the platform in the lateral direction L 2  via the lateral rails  105 ,  107 . The longitudinal guide rollers  121 ,  123  are connected to a mounting base  127  of the gearbox  27  to allow slidable movement and positioning of the DDU  23  in the longitudinal direction L 1  via the longitudinal rails  109 ,  111 . In one embodiment, the DDU positioner assembly  101  includes four lateral guide rollers  115 ,  117  and four longitudinal guide rollers  121 ,  123 , but more or less than eight guide rollers may be provided without departing from the scope of the disclosure. Further, more or less than two longitudinal rails  109 ,  111 , and more or less than two lateral rails  105 ,  107  may be provided without departing from the scope of the disclosure. In one embodiment, the guide rollers  115 ,  117 ,  121 ,  123  may be a caged ball type linear motion (LM) Guide, model number SPS20LR available from THK America Inc., or any similar make or model number without departing from the scope of the disclosure. The DDU positioner assembly  101  may be equipped with locking mechanisms  128  mounted on a respective guide roller  115 ,  117 ,  121 ,  123 . The locking mechanisms  128  may be spring loaded and will default to the locked position to allow the DDU  23  to be secured in the operating position. The locking mechanism  128  may be otherwise located on the positioning system  101  without departing from the disclosure. 
     Exemplary loading calculations for sizing the guide rails  105 ,  107 ,  109 ,  111  are shown below and are based on the Vericor TF50F turbine parameters as follows: approximate turbine weight, 1475 lbs.; approximate fuel system weight, 85 lbs.; approximate gearbox weight, 4000 lbs.; for a total approximate weight of 5559 lbs. Various other parameters may be applicable based on the make, model, and size of the gas turbine engine  25 . 
     Because of the arrangement the direct drive unit  23  including the gas turbine engine  25  cantilever mounted onto the gearbox  27  and extending in the longitudinal direction L 1  from the gearbox, there is added load put onto the rear lateral guide rollers  115  and the rear longitudinal guide rollers  121 ,  123  (the guide rollers mounted closest to the gas turbine engine). Accordingly, an increased load rating may be applied to the rear guide rollers  115 ,  121 ,  123  if required. The calculation of the cantilever load and the reaction forces may be calculated with the formulas shown below, which may also be used for further design and implementation of the disclosed removal mechanisms.
 
Maximum Reaction at the fixed end may be expressed as:  R   A   =qL.  
         where: R A =reaction force in A (N, lb), q=uniform distributed load (N/m, N/mm, lb/in), and L=length of cantilever beam (m, mm, in).
 
Maximum Moment at the fixed end may be expressed as  M   A   =−qL   2 /2
 
Maximum Deflection at the end may be expressed as δ B   =qL   4 /(8 EI ).
   where: δ B =maximum deflection in B (m, mm, in).       

     In one embodiment, the longitudinal guide rollers  121 ,  123  connected to the support structure  127  of the gearbox  27  are positioned between each pair of the lateral guide rollers  115 ,  117  to ensure equal weight distribution over the platform  103  and to avoid cantilever loading the platform. Different configurations of platforms, sliders, rails and mounts are contemplated and considered within the scope of the disclosure. The configurations of the DDU positioner assembly  101  may vary to suit a particular DDU  23  with various alternative combinations of makes, model, and sizes of the gas turbine engine  25  and the gearbox  27 . 
     In one embodiment, the guide rails  105 ,  107 ,  109 ,  111  are made from a steel composition that has been mill finished and shot blasted to protect the rail from the high heat environment within the turbine enclosure  21  and ensure strength retention under the exposed temperatures. In one embodiment, the platform  103  is constructed out of a composite material; however, other materials are contemplated and considered within the scope of the disclosure, such as but not limited to, steel or stainless steel. The guide rails  105 ,  107 ,  109 ,  111 , platform  103 , and/or other components of the DDU positioner assembly  101  may be made of various other suitable materials without departing from the scope of the disclosure. 
       FIGS.  6 A- 6 B  illustrate an exemplary method of removing the direct drive unit  23  from the enclosure  21  utilizing the DDU positioner assembly  101 .  FIG.  6 A  shows the DDU  23  in a first/operating position for operation with the pump  33  of the pumping unit  11 . The method includes accessing the enclosure  21  and disconnecting the gas turbine engine  25  from the air inlet ducting  37 . The flanges  51 ,  53  may be disconnected from the air inlet ducting  37  and the expansion joints  61 ,  63  flexed to allow separation of the DDU  23  from the air inlet ducting. The gas turbine engine  25  may be disconnected from the air exhaust ducting  35  by disconnecting the exhaust duct flange  54  from the air exhaust ducting. Corresponding hoses, piping, wiring, and cabling including fuel lines, electrical lines, hydraulic lines, control lines or any other connection that is needed for operation of the gas turbine engine  25  may also be disconnected so that the gas turbine engine is free to move without damaging any of the operational connections needed for operation of the gas turbine engine. For example, the air bleed off valve ducting may be removed from the turbine engine  25  and secured at a location free of interference with movement of the turbine engine. Alternatively, some hoses, piping, wiring, etc. may include enough slack or flexibility so that the DDU  23  may be initially moved before complete disconnection of the connections from the gas turbine engine  25  are required for removal of the DDU from the enclosure  21 . The gearbox  27  may be disconnected from the driveshaft  31  by disconnecting the outlet flange  50  from the driveshaft. In one embodiment, the driveshaft  31  may be a slip-fit driveshaft allowing the driveshaft to contract to facilitate disconnection from the DDU  23 . In one embodiment, the driveshaft  31  may be a 390 Series, GWB Model 390.80 driveshaft available Dana Corporation, or other suitable driveshaft. The gearbox  27  may be disconnected from any other connections needed for operation of the DDU  23  to obtain freedom of movement of the gearbox without damaging any of the operating connections. 
     Once the gas turbine engine  25  is disconnected from the respective connections and the gearbox  27  is disconnected from the driveshaft  31 , the DDU positioner assembly  101  is operated to position the direct drive unit  23  for withdrawal from the enclosure  21 . As shown in  FIG.  6 B , the DDU  23  is positioned in a second position where the DDU is first moved in the longitudinal direction L 1  in the direction of arrow A 1  by sliding the DDU along the longitudinal rails  109 ,  111 . In one embodiment, prior to initial movement of the DDU  23  in the longitudinal direction L 1 , the longitudinal locks  128  associated with the longitudinal guide rollers  121 ,  123  must be released to allow the movement of the DDU in the longitudinal direction. After the movement of the DDU  23  in the longitudinal direction L 1  to the second position, the longitudinal locks  128  may be reengaged to lock the longitudinal guide rollers  121 ,  123  and prevent further or additional unwanted movement of the DDU  23  along the longitudinal rails  109 ,  111 , and the lateral locks  128  associated with the lateral guide rollers  115 ,  117  may be disengaged to allow lateral movement of the DDU  23 . Next, the platform  103  may be moved to a third position by moving in the lateral direction L 2  in the direction of arrow A 2  ( FIG.  6 C ) by sliding movement of the lateral guide rollers  115 ,  117  along the lateral guide rails  105 ,  107 . The DDU  23  is mounted to the platform  103  and moves with the platform in the lateral direction L 2  to the third position of  FIG.  6 C . As shown in  FIGS.  3  and  5   , the lateral guide rails  105 ,  107  may extend to the access doors  45  in either side  55 ,  57  of the enclosure  21 . In some embodiments, lateral guide rail extensions  107 ′ ( FIG.  5   ) may be used to extend outside of the enclosure  21  to allow the platform  103  and DDU  23  to be slid out of the enclosure onto an adjacent supporting structure or vehicle (e.g., maintenance inspection platform or other suitable structure), or the platform  103  and DDU  23  may be accessed through the access doors  45  of the enclosure  21  by a lifting mechanism (e.g., a forklift, crane, or other suitable lifting mechanism) to fully remove the DDU from the enclosure. The various method steps described herein for the method of positioning or removing the DDU  23  may be otherwise performed in an alternative order or simultaneously, or more or less steps may be used without departing from the scope of the disclosure. 
       FIGS.  7 - 10    illustrates a second embodiment of a DDU positioner assembly or system  201  for positioning the direct drive unit  23  housed in the enclosure  21 . In the illustrated embodiment, the DDU  23  includes a gas turbine engine  25  and a gearbox  27  identical to the first embodiment of the disclosure, but the DDU positioner assembly  201  may be used to position a DDU that is alternatively configured without departing from the disclosure. As such, like or similar reference numbers will be used to describe identical or similar features between the two embodiments. 
     In one embodiment, the DDU positioner assembly  201  includes a platform  203  that supports the gearbox  27  and has a top surface  205 , a bottom surface  207 , two sides  208 , and two ends  210 . The gearbox  27  is fixedly mounted to the top surface  205  of the platform  203 . The platform  203  is slidably mounted on the base  41  of the enclosure  21  with the bottom surface  207  of the platform being in slidable engagement with the floor of the enclosure. In a first or operating position ( FIGS.  7  and  8 A ) of the direct drive unit  23 , the platform  203  is fixedly attached to the base  41  by a plurality of fasteners  211 . Upon removal of the fasteners  211 , the platform  203  is capable of slidable movement with respect to the base  41 . The platform  203  is connected to the support structure  127  of the gearbox  27  so that the drive unit  23  moves with the platform. In one embodiment, the platform  203  has two lifting openings  215 ,  217  extending between respective sides  208  of the platform. As shown in  FIG.  7   , the lifting opening  215  towards the front of the gearbox  27  (closest to the drive shaft flange  50 ) is spaced a first distance D 1  from a centerline CT of the gearbox and the lifting opening  217  towards the rear of the gearbox (closest to the gas turbine engine  25 ) is spaced a second distance from the centerline CT of the gearbox, with the distance D 2  being greater than the distance D 2 . The rear lifting opening  217  is farther from the centerline CT of the gearbox  27  because of the cantilever mounted gas turbine engine  25  that shifts the center of gravity of the DDU  23  from the centerline CT of the gearbox in the longitudinal direction toward the gas turbine engine. The platform  203  may be otherwise configured and/or arranged without departing from the scope of the disclosure. 
     In one embodiment, the DDU positioner assembly  201  includes a lubricator or lubrication system  221  ( FIG.  9   ) to convey lubricant (e.g., grease or other suitable lubricant) from a lubricant reservoir  244  to a location between the bottom surface  207  of the platform  201  and the base  41  of the enclosure. The DDU positioner assembly  201  includes a lubrication portion  225  ( FIG.  10   ) of the base  41  below the platform  203 . As shown in  FIG.  10   , the portion  225  of the base  41  includes a plurality of lubrication grooves  227 . The lubrication grooves  227  are in fluid communication with the lubricator  221  so that the lubricator provides lubricant to the grooves to facilitate sliding engagement between the platform  203  and the portion  225  of the base  41 . The lubricator  221  includes a source of lubricant  244 , tubing  243 , and other required components (e.g., pump, controls, etc.) for delivering the lubricant to the lubrication portion  225  at a sufficiently high pressure for lubricant to fill the grooves  227  of the lubrication portion  225 . In one embodiment, the lubricator  221  may be an automatic lubricator such as a model TLMP lubricator available from SKF Corporation, or the lubricator may be any other suitable lubricator including other automatic lubricators or manual lubricators without departing from the scope of the disclosure. In one embodiment, the lubrication portion  225  of the base  41  is an integral portion with the base or the floor of the enclosure  21 , but the lubrication portion  225  may be a separate pad or component that is mounted between the base and the platform without departing from the disclosure. The lubricator  221  may be mounted inside the enclosure  21  or at least partially outside the enclosure without departing from the scope of the disclosure. 
     In one embodiment, the DDU positioner assembly  201  includes drive fasteners  241  mounted at one end  210  of the platform  203 . In the illustrated embodiment, the drive fasteners  241  include a bracket  245  mounted to the floor  41  of the enclosure  21  and an impact screw  247  operatively connected to the bracket and the platform  203 . The drive fasteners  241  may have other components and be otherwise arranged without departing from the disclosure. Further, more or less than two drive fasteners  241  may be provided without departing from the disclosure. 
       FIGS.  8 A- 9    illustrate an exemplary method of removing the DDU  23  from the enclosure  21  utilizing the DDU positioner assembly  201  of the second embodiment. The method is similar to the method of the first embodiment, in that the gas turbine engine  25  is disconnected from the air inlet ducting  37 , the air exhaust ducting  35 , and from other corresponding connections and components in a similar manner as discussed above for the first embodiment so that the gas turbine engine is free to move without damaging any of the operational connections and components needed for operation of the gas turbine engine. Further, the gearbox  27  is disconnected from the driveshaft  31  in a similar manner as the first embodiment, so that the DDU  23  has clearance for movement in the longitudinal direction L 1  without interference with the driveshaft. 
       FIG.  8 A  shows the direct drive unit  23  in the first/operating position. Once the gas turbine engine  25  is disconnected from the respective components and connections and the gearbox  27  is disconnected from the driveshaft  31  and any other connections, the DDU positioner assembly  201  is operated to position the DDU  23  for withdrawal from the enclosure  21 . First, the fasteners  211  fixedly attaching the platform  203  to the base  41  are removed. The lubricator  221  is operated to convey lubricant to the lubrication grooves  227  of the lubrication portion  225  of the base  41 . After a sufficient amount of lubrication is located between the platform  203  and the lubrication portion  225  of the base  41 , the drive fasteners  241  may be operated to move the platform  203  in the longitudinal direction L 1  to a second position ( FIG.  8 B ). As the impact screws  247  of the drive fasteners  241  are turned, the platform  203  is slid in the longitudinal direction L 1  in the direction of arrow A 3  ( FIG.  8 B ). The lubricant provided in the lubrication grooves  227  and between the lubrication portion  225  and the bottom surface  207  of the platform reduces the sliding friction and allows the rotation of the impact screws  247  in the bracket  245  to advance the platform in the direction of arrow A 3 . The platform  203  is moved in the direction of arrow A 3  a sufficient amount to allow access to the lifting openings  215 ,  217  by a lifting mechanism (e.g., forklift)  261  ( FIG.  8 C ). The lifting mechanism  261  may include a forklift or other lifting mechanism that may access the interior  46  of the enclosure through the enclosure access doors  45 . The lifting mechanism  261  is inserted into the lifting openings  215 ,  217  of the platform  203 , and the DDU  23  is lifted and/or slid in the direction of arrow A 4 . The lifting mechanism  261  may move the DDU  23  to the third position ( FIG.  8 C ), or transfer the DDU onto an adjacent supporting structure or vehicle (e.g., maintenance inspection platform or other suitable structure), or completely remove the platform  203  and DDU  23  from the enclosure. The various method steps described herein for the method of positioning or removing the DDU  23  by operating the DDU positioner assembly  201  may be otherwise performed in an alternative order or simultaneously, or more or less steps may be used without departing from the scope of the disclosure. 
       FIGS.  11 - 12 C  illustrate a third embodiment of a DDU positioner assembly or system  301  for positioning the direct drive unit  23  housed in the enclosure  21 . In the illustrated embodiment, the DDU  23  includes a gas turbine engine  25  and a gearbox  27  identical to the first and second embodiments of the disclosure, but the DDU positioner assembly  301  may be used to position a DDU that is alternatively configured without departing from the disclosure as will be understood by those skilled in the art. The DDU positioner assembly  301  is generally similar to the DDU positioner assembly  201  of the second embodiment, except the drive fasteners  241  have been removed and an actuator  341  is added to the DDU positioner assembly of the third embodiment. As such, like or similar reference numbers will be used to describe identical or similar features between the second and third embodiments. 
     As shown in  FIG.  11   , the DDU positioner assembly  301  includes the actuator  341  that has a first end  345  connected to the base  41  of the enclosure  21  and a second end  347  connected to the end  210  of the platform  203 . In one embodiment, the actuator  341  is a hydraulic cylinder that has a piston rod  351  that is extendible from a cylinder body  349  upon operation of the actuator. The actuator  341  may be controlled by a manual control valve or the actuator may be configured for remote operation by connection to corresponding automated control valves. In the illustrated embodiment, one actuator  341  is shown, but the DDU positioner assembly  301  may include more than one actuator without departing from the scope of the disclosure. Further, the actuator  341  may be otherwise located for attachment to the platform  203  without departing from the scope of the disclosure. 
       FIGS.  12 A- 12 C  illustrate an exemplary method of removing the DDU  23  from the enclosure  21  utilizing the DDU positioner assembly  301  of the second embodiment. The method is similar to the method of the utilizing the DDU positioner assembly  201  of the second embodiment, in that the gas turbine engine  25  is disconnected from the air inlet ducting  37 , the air exhaust ducting  35 , and from other corresponding connections and components in a similar manner as discussed above for the first embodiment so that the gas turbine engine is free to move without damaging any of the operational connections and components needed for operation of the gas turbine engine. Further, the gearbox  27  is disconnected from the driveshaft  31  in a similar manner as the first embodiment, so that the DDU  23  has clearance for movement in the longitudinal direction L 1  without interference with the driveshaft. Also, the DDU positioner assembly  301  of the third embodiment includes the lubricator  221  ( FIG.  9   ) for providing lubrication to lubrication grooves  227  of the lubrication portion  225  of the base  41  to facilitate sliding of the platform  203  in the longitudinal direction L 1 , so that the DDU positioner assembly of the third embodiment operates in a similar manner as the DDU positioner assembly  201  of the second embodiment. 
       FIG.  12 A  shows the direct drive unit  23  in the first/operating position. Once the gas turbine engine  25  is disconnected from the respective components and connections, and the gearbox  27  is disconnected from the driveshaft  31  and any other connections, the DDU positioner assembly  301  is operated to position the DDU  23  for withdrawal from the enclosure  21 . First, the fasteners  211  fixedly attaching the platform  203  to the base  41  are removed. The lubricator  221  is operated to convey lubricant to the lubrication grooves  227  of the lubrication portion  225  of the base  41 . After a sufficient amount of lubrication is located between the platform  203  and the lubrication portion  225  of the base  41 , the actuator  341  may be operated to move the platform  203  in the longitudinal direction L 1  to a second position ( FIG.  12 B ). The extension of the piston rod  351  of the actuator  341  exerts a force on the platform  203  to slide the platform in the longitudinal direction L 1  in the direction of arrow A 3  ( FIG.  12 B ). The lubricant provided in the lubrication grooves  227  and between the lubrication portion  225  and the bottom surface  207  of the platform reduces the sliding friction and allows the actuator  341  to advance the platform in the direction of arrow A 3 . As with the previous embodiment, the platform  203  is moved in the direction of arrow A 3  a sufficient distance to allow access to the lifting openings  215 ,  217  by a lifting mechanism (e.g., forklift)  261  ( FIG.  8 C ). The lifting mechanism  261  may include a forklift or other lifting mechanism that may access the interior  46  of the enclosure through the enclosure access doors  45 . The lifting mechanism  261  is inserted into the lifting openings  215 ,  217  of the platform  203 , and the DDU  23  is lifted and/or slid in the direction of arrow A 4 . Prior to moving the platform  203  in the direction of arrow A 4 , the actuator  341  may be disconnected from the platform ( FIG.  12 C ) with the first end  347  of the actuator being separated from the platform and the second end  345  of the actuator remaining attached to the floor  41  of the enclosure. Alternatively, the second end  345  of the actuator  341  may be disconnected from the floor  41  of the enclosure and the first end  341  of the actuator may remain attached to the platform  203 , or both ends of the actuator may be disconnected and the actuator removed without departing from the enclosure. 
     The lifting mechanism  261  may move the DDU  23  to the third position ( FIG.  12 C ), or transfer the DDU onto an adjacent supporting structure or vehicle (e.g., maintenance inspection platform or other suitable structure), or completely remove the platform  203  and DDU  23  from the enclosure. The various method steps described herein for the method of positioning or removing the DDU  23  by operating the DDU positioner assembly  301  may be otherwise performed in an alternative order or simultaneously, or more or less steps may be used without departing from the scope of the disclosure. 
     Having now described some illustrative embodiments of the disclosure, it should be apparent to those skilled in the art that the foregoing is merely illustrative and not limiting, having been presented by way of example only. Numerous modifications and other embodiments are within the scope of one of ordinary skill in the art and are contemplated as falling within the scope of the disclosure. In particular, although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. Those skilled in the art should appreciate that the parameters and configurations described herein are exemplary and that actual parameters and/or configurations will depend on the specific application in which the systems and techniques are used. Those skilled in the art should also recognize or be able to ascertain, using no more than routine experimentation, equivalents to the specific embodiments of the disclosure. It is, therefore, to be understood that the embodiments described herein are presented by way of example only and that, within the scope of any appended claims and equivalents thereto; the embodiments of the disclosure may be practiced other than as specifically described. 
     This application is a continuation of U.S. Non-Provisional application Ser. No. 17/936,885, filed Sep. 30, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” which is a continuation of U.S. Non-Provisional application Ser. No. 17/883,693, filed Aug. 9, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,512,642, issued Nov. 29, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/808,792, filed Jun. 24, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,473,503, issued Oct. 18, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/720,390, filed Apr. 14, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,401,865, issued Aug. 2, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/671,734, filed Feb. 15, 2022, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,346,280, issued May 31, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/204,338, filed Mar. 17, 2021, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 11,319,878, issued May 3, 2022, which is a continuation of U.S. Non-Provisional application Ser. No. 17/154,601, filed Jan. 21, 2021, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,982,596, issued Apr. 20, 2021, which is a divisional of U.S. Non-Provisional application Ser. No. 17/122,433, filed Dec. 15, 2020, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,961,912, issued Mar. 30, 2021, which is a divisional of U.S. Non-Provisional application Ser. No. 15/929,924, filed May 29, 2020, titled “DIRECT DRIVE UNIT REMOVAL SYSTEM AND ASSOCIATED METHODS,” now U.S. Pat. No. 10,895,202, issued Jan. 19, 2021, which claims the benefit of and priority to U.S. Provisional Application No. 62/899,975, filed Sep. 13, 2019, titled “TURBINE REMOVAL SYSTEM,” the entire disclosures of which are incorporated herein by reference. 
     Furthermore, the scope of the present disclosure shall be construed to cover various modifications, combinations, additions, alterations, etc., above and to the above-described embodiments, which shall be considered to be within the scope of this disclosure. Accordingly, various features and characteristics as discussed herein may be selectively interchanged and applied to other illustrated and non-illustrated embodiment, and numerous variations, modifications, and additions further may be made thereto without departing from the spirit and scope of the present disclosure as set forth in the appended claims.