Lubrication system for a plunger/packing set of a fluid end

Abstract

A lubrication system for a plunger/packing set of a fluid end has a lubricating fluid reservoir, a pump cooperative with the lubricating fluid reservoir so as to pump a lubricating fluid from the lubricating fluid reservoir toward the plunger/packing set, a primary pressure transducer cooperative with the pump so as to measure a pressure of the lubricating fluid exiting the fluid pump, a secondary pressure transducer cooperative with the fluid end so as to measure a pressure of the lubricating fluid exiting the plunger/packing set, and a controller connected to the second pressure transducer so as to obtain a representation of the pressure measured by the secondary pressure transducer.

Claims

1. A lubrication system comprising: a fluid end having a plunger/packing set therein; a lubricating fluid reservoir; a pump cooperative with said lubricating fluid reservoir so as to pump a lubricating fluid from said lubricating fluid reservoir toward said plunger/packing set, said fluid end having a lubricating fluid inlet and a lubricating fluid outlet; a primary pressure transducer cooperative with said pump so as to measure a pressure of the lubricating fluid exiting said pump and before the lubricating fluid inlet of said fluid end; a secondary pressure transducer cooperative with said fluid end so as to measure a pressure of the lubricating fluid exiting said plunger/packing set; and a controller connected to said secondary pressure transducer so as to obtain a representation of the pressure of the lubricating fluid measured by said secondary pressure transducer.

2. The lubrication system of claim 1, said fluid end comprising a plurality of plunger/packing sets, the lubrication system further comprising: a manifold connected by a conduit to said pump, said manifold receiving the lubricating fluid therein; and a plurality of lines extending from said manifold to each of said plurality of plunger/packing sets.

3. The lubrication system of claim 2, said secondary pressure transducer comprising: a plurality of secondary pressure transducers cooperative with the lubricating fluid exiting said plurality of plunger/packing sets, said plurality of secondary pressure transducers being connected to said controller.

4. The lubrication system of claim 2, further comprising: a plurality of check valves mounted on said plurality of lines extending from said manifold, said plurality of check valves preventing a flow of lubricating fluid toward said, manifold.

5. The lubrication system of claim 3, said plurality of secondary pressure transducers having respectively a plurality of conduits extending from said plurality of plunger/packing set, each of said plurality of conduits having a bleed valve thereon.

6. The lubrication system of claim 1, further comprising: a collection tray position downstream of said fluid end, said collection tray adapted to receive the lubricating fluid after exiting said fluid end.

7. The lubrication system of claim 2, further comprising: a relief valve connected to the conduit in a location downstream of said primary pressure transducer, said relief valve limiting a pressure of the lubricating fluid passing to said fluid end.

8. The lubrication system of claim 7, said relief valve limiting the fluid pressure to no more than 100 p.s.i.

9. The lubrication system of claim 7, said relief valve cooperative with said reservoir so as to return excess pressures of the lubricating fluid back to said reservoir.

10. The lubrication system of claim 3, said controller monitoring the fluid pressure at the plurality of secondary pressure transducers and at the primary pressure transducer.

11. The lubrication system of claim 1, further comprising: a two speed motor connected to said pump so as to drive said pump selectively at either a first speed or a second speed.

12. The lubrication system of claim 1, further comprising: a fill line connected to said reservoir, said fill line adapted to add lubrication fluid to an interior of said reservoir.

13. The lubrication of system of claim 1, further comprising: a data cable connected to said controller, said data cable adapted to transmit data from said controller to a remote location.

14. A process for lubricating a fluid end, the process comprising: flowing a lubricating fluid from a reservoir to a plunger/packing set of the fluid end; measuring a pressure of the lubricating fluid as the lubricating fluid flows from the reservoir to the plunger/packing set; lubricating the plunger/packing set in the fluid end with a portion of the lubricating fluid; passing a remainder of the lubricating fluid outwardly of the plunger/packing set; measuring a pressure of the remainder of the lubricating fluid that passes outwardly of the plunger/packing set; and monitoring the measured pressures so as to determine a condition of the plunger/packing set within the fluid end.

15. The process of claim 14, the pressure of the lubricating fluid flowing to the plunger/packing set of the fluid end being no more than 100 p.s.i.

16. The process of claim 14, the step of flowing the lubricating fluid comprising: flowing the lubricating fluid from the reservoir into a manifold.

17. The process of claim 16, the fluid end having a plurality of plunger/packing sets, the step of flowing further comprising: flowing the lubricating fluid from the manifold through a plurality of lines to the plurality of plunger/packing sets, the step of lubricating comprising lubricating the plurality of plunger/packing sets.

18. The process of claim 17, the step of measuring the pressure of the remainder of the lubricating fluid comprising: measuring the fluid pressure of the remainder of the lubricating fluid from each of the plurality of plunger/packing sets.

19. The process of claim 18, the step of monitoring comprising: monitoring the measured fluid pressure of the remainder of the lubricating fluid from each of the plurality of plunger/packing sets so as to determine differences in fluid pressure between each of the plurality of plunger/packing sets.

20. The process of claim 14, further comprising: relieving pressure in excess of a desired pressure by returning an excess lubricating fluid back to the reservoir before the lubricating fluid flows to the plunger/packing set.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a prior art fluid end assembly.

(2) FIG. 2 is a cross-sectional view showing a reciprocating pump and fluid end assembly employing the lubrication system of the present invention.

(3) FIG. 3 is a diagrammatic illustration of the lubrication system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) Referring to FIG. 2 is a cut-away view that schematically illustrates a plunger pump 10. The plunger pump 10 can be a well service pump and includes a fluid end 12, a power end 14 and a plunger 16. Fluid end 12 has a suction valve 18 and a discharge valve 20 in fluid communication through a first bore 22. A cylinder 24 intersects the first bore 22 and has a port 26. A packing 28 includes a packing gland 30 disposed at port 26. Plunger 16 reciprocates through the packing 28 and the packing gland 30.

(5) The plunger pump 10 has the lubrication system 32 fluidically connected to the packing gland 30. FIG. 2 schematically illustrates the lubrication system 32 having the lubricant 34 (e.g. oil, grease) connected through an inlet port 36 to the packing gland 30. The lubricant 34 is provided under pressure by way of pump 38. The lubricant passes through a check valve 40 to the packing gland 30. Lubrication system 32 further includes a discharge line 42 connected to the packing gland 30 through a discharge port 44. A primary pressure transducer 41 detects fluid pressure in the fluid conduit between the pump 38 and the check valve 40. A secondary pressure transducer 43 detects pressure of the lubricating fluid passing through the discharge line 42. A collection tray 48 is located at the end of the discharge line 42 so as to receive excess lubricant from discharge line 42.

(6) In normal use of the system shown in FIG. 2, the primary pressure transducer 41 measures the pressure of the lubricating fluid passing from the pump 38 to the check valve 40. The check valve 40 prevents the return of lubricating fluid. As will be described hereinafter, the conduit 45 extending from the pump 38 to the plunger 16 and the packing 28 will flow the lubricating fluid to a manifold and then pass to each of the plunger/packing sets within the fluid end. This is shown fully in FIG. 3. The secondary pressure transducer 43 will measure the pressure of the lubricating fluid passing through the discharge line 42. In normal use, a portion of the lubricating fluid will be received by the packing 28 and the plunger 16. The remainder of the lubricating fluid will flow outwardly through the discharge line 42 and into the collection tray 48. A change of the pressure measured by the secondary pressure transducer 43 can be indicative of damage or misalignment of the plunger/packing set. As such, this can be indicative of the need for repair. Ultimately, since the pressure regulator maintains the fluid pressure of the fluid passing through the conduit 45 at 100 p.s.i. or less, and since the secondary pressure transducer 43 measures the pressure of the discharged lubricating fluid, assessments can be properly made as to the conditions of the plunger/packing set within the fluid end 12. For example, if the plunger/packing set refuses to accept the 100 p.s.i. fluid pressure, then this can be indicative of the obstructions in the plunger/packing set. If the pressure sensed by the secondary pressure transducer 43 senses a great difference in pressure between the pressure sensed by the first pressure transducer 41 and the second pressure transducer 43 is beyond expected parameters or varies greatly, then this can be indicative of process pressure and onset of packing or other internal failings.

(7) FIG. 3 is a diagrammatic illustration of the lubricating system 50 of the present invention. This lubricating system 50 includes a reservoir 52, a pump 54, a manifold 56, a plurality of plunger/packing sets 58, a first pressure transducer 60 and a plurality of secondary pressure transducers 62.

(8) Each of the plurality of fluids 58 includes at least one plunger/packing set (as shown in FIG. 2). Each of the fluid ends 58 includes a lubricating fluid inlet 64 and a lubricating fluid outlet 66. The lubricating fluid will pass through the fluid ends 58 so as to properly lubricate the plunger/packing set therein.

(9) The lubricating fluid reservoir 52 has a supply of lubricating fluid, such as grease, therein. A fill line 68 extends to the lubricating fluid reservoir 52 so as to supply additional lubricating fluid to the interior of the reservoir 52, when required. The pump 54 is cooperative with the lubricating fluid reservoir 52. A two speed motor 72 is operatively connected to the pump 54 so as to operate the pump 54 at a first speed or a second speed. One speed is adapted to deliver lubricating fluid from the reservoir 52 to the plurality of plunger/packing sets of the fluid end 58. The other speed is used for the purging of the plunger/packing sets of fluid end 58 and the lines associated therewith. The pump 54 is adapted to deliver the lubricating fluid, under pressure, to the plurality of plunger/packing set of the fluid end 58.

(10) The primary pressure transducer 60 is cooperative with a conduit 74 that extends from the pump 54. The primary pressure transducer 60 measures the pressure of the lubricating fluid exiting the pump 54 prior to entering the lubricating fluid inlet 64 of the fluid end 58. A pressure regulator/relief valve 76 is also connected to the conduit 64. The pressure regulator/relief valve 76 serves to fix the pressure of the lubricating fluid in the conduit 64 to no more than 100 p.s.i. The pressure regulator/relief valve 76 can deliver excess lubricating fluid along line 78 back to the lubricating fluid reservoir 52.

(11) The conduit 74 is connected to the manifold 56. Manifold 56 allows the lubricating fluid to be delivered along lines 80, 82, 84, 86 and 88 to the plurality of plunger/packing sets fluid end 58. Check valves 90 are positioned on each of the lines 80, 82, 84, 86 and 88 so as to prevent the return flow of lubricating fluid from the plurality of plunger/packing sets of fluid end 58.

(12) The lubricating fluid will pass through the interior of the plurality of fluid end 58 so as to lubricate the plunger/packing set therein. The remaining lubricating fluid will pass outwardly through the lubricating fluid outlet 66 of the plunger/packing set. It will then flow through conduits 92, 94, 96, 98 and 100 to the plurality of secondary pressure transducers 62. Separate secondary pressure transducers 62 are cooperative with the lubricating fluid in each of the conduits 92, 94, 96, 98 and 100 so as to separately measure the pressure of the lubricating fluid therein. Bleed valves 102 are provided on each of the pipes 92, 94, 96, 98 and 100 so as to selectively allow for purging.

(13) Ultimately, any lubricating fluid escaping the system will be received within a collection tray 104.

(14) Importantly, in the present invention, a controller 110 is connected to each of the plurality of secondary pressure transducers 62 and to the primary pressure transducer 60. As such, the pressures measured by the primary pressure transducer 60 and the secondary pressure transducer 62 can be received by the controller 110. A data cable 112 can be connected to the controller 110 so as to deliver this information to a remote location, such as monitoring equipment on a frac truck.

(15) In the present invention, if there is a change of pressure noted amongst the various secondary pressure transducers 62, attention can be directed toward the particular plunger/packing set associated with that pressure transducer. As such, as these changes are noted, repairs can be made or assessments can be made as to the particular fluid end. The notation of such changes can provide a great deal of benefit to operators in order to avoid a premature failure or destruction of the fluid end. Additionally, by limiting the lubricating fluid provided to the plurality of plunger/packing sets, the amount of lubricating fluid consumed by the lubricating system 50 of the present invention can be minimized. There is no need to flow excess lubricating fluid in order to effectively lubricate the system. The amount of lubricating fluid delivered is maintained at a very constant pressure and at an optimal volume.

(16) Lubricating system 50 of the present invention utilizes a single unit to service the plunger/packing sets of various fluid ends. The system pumps lubricating fluid, in normal operation, at 100 p.s.i. which the supplies all of the lubrication required. While the packing is healthy, a fluid end will not accept lubricating fluid at more than 100 p.s.i. The pump 54 pumps lubricating to the manifold 56 attached thereto which is attached the primary pressure transducer 60, the relief valve 76 and the flow line connections for the number of plungers in the fluid end to be serviced. Since the packing does not require more than 100 p.s.i. of lubrication, the pressure relief valve 76 relieves at 100 p.s.i. and allows this excess lubrication fluid to flow and returned to the lubricating fluid reservoir 52. The primary pressure transducer 60 supplies data to the controller 110. The data cable 112 can be installed from the frac truck located control unit to a secondary monitoring unit which can be located in the frac data trailer with other real-time monitoring equipment.

(17) The lubricating fluid that is accepted flows beyond the relief valve 60 through the individual flow line connections 80, 82, 84, 86 and 88 toward the plunger/packing set. The lubricating fluid flowing through each of the flow lines 80, 82, 84, 86 and 88 first passes the check valve 90 and then flows into the individual lower lubrication fluid ports on the bottom of the plunger/packing set. A bleed valve 102 and secondary pressure transducer 62 are attached to the upper lubricating fluid outlet 66 for each of the plunger/packing sets of the fluid ends. The secondary pressure transducer 62 reads and supplies the lubricating fluid pressure detected for each plunger/packing set. This information is then transmitted to the controller 110. The data cable 112 can deliver this information to a secondary monitoring unit located with other real-time monitoring equipment so as to assess the progression of the fracturing or other well servicing operation in progress. Parameters are set within the controller 110 and the remote monitoring units so as to trigger warnings and to provide readouts of pressures available to the field team.

(18) The two speed motor 72 and the pump 54 in conjunction with the manifold provides for variable pump flow and allows for simultaneous purging of all lines without additional equipment.

(19) The lubrication system 50 of the present invention lowers lubrication fluid usage to the amount actually required. This reduces expense and reduces the cost of used lubrication fluid disposal by as much as 50%. The lubrication system 50 lowers purging time and the expense associated therewith. The lubrication system 50 provides a new and safe real-time assessment of lubrication metrics. This allows earlier detection ofpacking failure, the need for packing adjustment, or other conditions of the fluid end or frac pump that would warrant attention. The early detection of packing failure or the need for packing adjustment will allow the fluid ends to be serviced in advance of block damage or failure. As such, the losses associated with block failure can be avoided.

(20) The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction and in the steps of the described method can be made within the scope of the present invention without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.