Title:
Centrifugal pump systems
Kind Code:
A1


Abstract:
A pumping system for pumping a mixture, e.g. a drilling fluid mixture, containing liquid and solids, the pumping system including a container, centrifugal pump apparatus for pumping the mixture, the pump apparatus including a pump shaft, a drive motor, a shaft packing structure, and bearing apparatus around the pump shaft, the packing structure, bearing apparatus and part of the pump shaft within an enclosed non-vented housing. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 CFR 1.72(b).



Inventors:
Love, William Wray (Montgomery, TX, US)
Angelle, Clinton James (Breaux Bridge, LA, US)
Application Number:
11/977424
Publication Date:
04/30/2009
Filing Date:
10/24/2007
Primary Class:
Other Classes:
417/423.12
International Classes:
F04D25/00
View Patent Images:
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Primary Examiner:
WIEHE, NATHANIEL EDWARD
Attorney, Agent or Firm:
National Oilwell Varco (Houston, TX, US)
Claims:
What is claimed is:

1. A pumping system for pumping a drilling mixture containing liquid drilling fluid and solids entrained in the liquid drilling fluid, the pumping system comprising a container for receiving and holding the drilling mixture, centrifugal pump apparatus for transferring the drilling mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, a housing, the housing comprising an enclosed non-vented structure, and the packing structure, bearing apparatus and part of the pump shaft within the housing.

2. The pumping system of claim 1 further comprising seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing.

3. The pumping system of claim 1 further comprising a lubricant port through the housing for providing lubricant to the bearing apparatus.

4. The pumping system of claim 3 further comprising lubricant within the housing for lubricating the bearing apparatus, the lubricant expandable upon heating to increase pressure within the housing to inhibit contaminants from entering the housing through the pump-shaft/housing interface.

5. The pumping system of claim 2 wherein the seal apparatus contains at least one seal.

6. The pumping system of claim 1 wherein the packing structure surrounds the pump shaft and maintains the bearing apparatus in position adjacent the pump shaft and above the packing structure.

7. The pumping system of claim 6 wherein the packing structure inhibits contaminants from flowing to the bearing apparatus.

8. The pumping system of claim 6 further comprising a retainer with a base and a cylinder, the cylinder encircling a portion of the drive shaft and the base abutting a bottom of the packing structure.

9. The pumping system of claim 8 wherein the retainer acts as a barrier inhibiting contaminants from contacting the pump shaft.

10. The pumping system of claim 8 further comprising seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing, the seal apparatus including at least one seal, and the at least one seal sealingly contacting an exterior surface of the retainer ring's cylinder.

11. The pumping system of claim 6 wherein the packing structure comprises at least one seal, and at least one retainer ring for holding the seal in a sealing position.

12. The pumping system of claim 11 wherein the at least one retainer ring has a ring diameter, the bearing apparatus has a bearing diameter, and the ring diameter is greater than the bearing diameter.

13. The pumping system of claim 8 further comprising impeller apparatus on the pump shaft, the impeller apparatus abutting the retainer.

14. The pumping system of claim 8 wherein the retainer supports and guides the pump shaft in the event of failure of the bearing apparatus.

15. The pumping system of claim 11 further comprising a grease port for introducing grease into the housing for the at least one seal of the seal apparatus.

16. The pumping system of claim 12 further comprising grease adjacent the at least one seal, the grease under pressure to provide a positive internal pressure at a location of the packing structure.

17. A pumping system for pumping a drilling mixture containing liquid drilling fluid and solids entrained in the liquid drilling fluid, the pumping system comprising a container for receiving and holding the drilling mixture, centrifugal pump apparatus for transferring the drilling mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, a housing, the housing comprising an enclosed non-vented structure, the packing structure, bearing apparatus and part of the pump shaft within the housing, seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing, the packing structure surrounds the pump shaft and maintains the bearing apparatus in position adjacent the pump shaft and above the packing structure, the packing structure inhibits contaminants from flowing to the bearing apparatus, a retainer with a base and a cylinder, the cylinder encircling a portion of the drive shaft and the base abutting a bottom of the packing structure, and the retainer acts as a barrier inhibiting contaminants from contacting the pump shaft.

18. A centrifugal pump apparatus comprising a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft, bearing apparatus around the pump shaft, a housing comprising a non-vented housing, and the packing structure, bearing apparatus and part of the pump shaft within the housing.

19. A method for pumping a mixture containing liquid and solids, the method comprising feeding the mixture from a container for receiving and holding the mixture to a centrifugal pump apparatus for transferring the mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a housing, a packing structure around the pump shaft and bearing apparatus around the pump shaft, the housing comprising a non-vented housing, the packing structure, bearing apparatus and part of the pump shaft within the housing, and with the centrifugal pump, pumping the mixture from the container.

20. A pumping system for pumping a mixture containing liquid and solids, the pumping system comprising a container for receiving and holding the mixture, centrifugal pump apparatus for transferring the mixture from the container, the centrifugal pump apparatus including housing, a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, the housing comprising a non-vented enclosure, and the packing structure, bearing apparatus and part of the pump shaft within the housing.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to centrifugal pumps; to systems using them; and, in certain particular aspects, to such systems for pumping solids-laden drilling fluids.

2. Description of Related Art

The prior art discloses a wide variety of centrifugal pumps; systems that employ them; and systems with such pumps for pumping drilling fluid laden with drilled solids and other solid components; for example, and not by way of limitation, see U.S. Pat. Nos. 5,456,580; 5,662,807; 5,846,440; 6,096,228; 6,170,580; 6,179,071; 6,276,824; 6,345,672; 6,406,255; and 6,808,354, all of said patents incorporated fully herein for all purposes.

Pumping systems which employ centrifugal pumps are used to pump mixtures and slurries that contain solids. In certain particular aspects, such systems pump fluids used in the drilling of earth wellbores, tunneling and excavating. Drilling fluids can contain hazardous material, oil, solids, debris, rock, and shale cuttings.

The safe and efficient handling of drilling fluid and its proper disposal result in significant expense in drilling a wellbore.

There has long been a need, recognized by the present inventors, for effective and efficient systems employing centrifugal pumps for pumping mixtures with solids therein. There has long been a need, recognized by the present inventors, for effective and efficient systems for pumping solids-laden drilling fluids.

BRIEF SUMMARY OF THE INVENTION

The present invention discloses, in certain aspects, systems for pumping mixtures with solids therein. In certain aspects, such systems include a container or tank for receiving and holding the mixture; apparatus for moving the mixture within and from the container; and one or more centrifugal pumps for transferring the mixture from the container to storage or disposal (and/or to mix the mixture within the container to make it homogeneous).

In certain aspects the mixture contained within a container is a slurry which includes a fluid or fluids and solids in the fluid. In one particular aspect, the mixture is a slurry of drilling fluid from a wellbore with solids (e.g. drilled cuttings, drilled debris, etc.) therein.

In certain particular aspects, the present invention discloses a centrifugal pump with a packing structure for a pump shaft. The packing structure includes seals that act as containment barriers to prevent outside contamination from entering a pump housing and contacting the shaft and other parts. In certain aspects, the packing structure is sealed within a non-vented space below bearings, a space in which a positive pressure is maintained. Also, with seals isolated and under pressure, and located in a non-vented space, as temperature builds up during operation, lubricant adjacent the seals expands, increasing pressure as compared to pressure external to the packing structure, which contributes to maintaining the seals in isolation and to prohibiting contaminants from entering the system and flowing to the bearings. Thus, the life of parts, e.g. shafts and bearings, can be extended.

In certain aspects, the present invention discloses pumping systems for pumping a drilling mixture containing liquid drilling fluid and solids (e.g., debris, drilled cuttings, etc.) entrained in the liquid drilling fluid, the pumping systems including: a container for receiving and holding the drilling mixture; centrifugal pump apparatus for transferring the drilling mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, a housing, the housing comprising an enclosed non-vented structure; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

The present invention discloses, in certain aspects, centrifugal pump apparatus including: a pump shaft; a motor to drive the pump shaft; a packing structure around the pump shaft; bearing apparatus for the pump shaft; a non-vented housing able to contain lubricant and/or grease under pressure; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

In certain aspects, the present invention discloses methods for pumping a mixture containing liquid and solids (in one particular aspect, a mixture of drilling fluid and drilled solids), the method including: feeding the mixture from a container for receiving and holding the mixture to a centrifugal pump apparatus for transferring the mixture from the container, the centrifugal pump apparatus being any according to the present invention; and with the centrifugal pump, pumping the mixture from the container.

The present invention discloses, in certain aspects, pumping systems for pumping a mixture containing liquid and solids, the pumping systems including: a container for receiving and holding the mixture; centrifugal pump apparatus for transferring the mixture from the container; the centrifugal pump apparatus including a non-vented housing that is able to hold pressure.

What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain preferred embodiments of the invention, there are other objects and purposes which will be readily apparent to one of skill in this art who has the benefit of this invention's teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:

New, useful, unique, efficient, non-obvious pumping systems; methods of their use; and centrifugal pump apparatus for use with them;

Such pumping systems with a pump having an isolated packing structure with a relatively high internal pressure which effectively prevents contaminants from entering the system and flowing to items above the packing structure, e.g. preserving vital parts, e.g. bearings and shafts;

Such pumping systems and methods in which a packing structure is located in a non-vented space; and

In certain aspects, such a pump in which lubricant heated during operation increases pressure on the packing structure.

Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.

The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention's realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of certain preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent's object to claim this invention no matter how others may later attempt to disguise it by variations in form, changes, or additions of further improvements.

The Abstract that is part hereof is to enable the U.S. Patent and Trademark Office and the public generally, and scientists, engineers, researchers, and practitioners in the art who are not familiar with patent terms or legal terms of phraseology to determine quickly from a cursory inspection or review the nature and general area of the disclosure of this invention. The Abstract is neither intended to define the invention, which is done by the claims, nor is it intended to be limiting of the scope of the invention in any way.

It will be understood that the various embodiments of the present invention may include one, some, or all of the disclosed, described, and/or enumerated improvements and/or technical advantages and/or elements in claims to this invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. These drawings illustrate certain preferred embodiments and are not to be used to improperly limit the scope of the invention which may have other equally effective or legally equivalent embodiments.

FIG. 1 is a perspective view of a pumping system according to the present invention.

FIG. 2 is a perspective view of the system of FIG. 1.

FIG. 3 is a side schematic side view of part of the system of FIG. 1.

FIG. 4 is a perspective view of a pump according to the present invention of the system of FIG. 1.

FIG. 5 is a front view of the pump of FIG. 4.

FIG. 6 is an underside view of the pumps of FIG. 4.

FIG. 7 is a cutaway view along line 7-7 of FIG. 5.

FIG. 8 is a cross-sectional view of the pump along line 8-8 of FIG. 6.

FIG. 9A is a side view of a pump according to the present invention.

FIG. 9B is a cross-sectional view along line 9B-9B of the pump of FIG. 9A.

FIG. 9C is an enlarged view of part of the pump of FIG. 9B.

FIG. 10A is an exploded perspective view of part of the pump of FIG. 9A.

FIG. 10B is an enlarged perspective view of part of the pump of FIG. 10A.

FIG. 11 is a cross-section view of a prior art seal useful with the pump of FIG. 9A.

Presently preferred embodiments of the invention are shown in the above-identified figures and described in detail below. Various aspects and features of embodiments of the invention are described below and some are set out in the dependent claims. Any combination of aspects and/or features described below or shown in the dependent claims can be used except where such aspects and/or features are mutually exclusive. It should be understood that the appended drawings and description herein are of preferred embodiments and are not intended to limit the invention or the appended claims. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. In showing and describing the preferred embodiments, like or identical reference numerals are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

As used herein and throughout all the various portions (and headings) of this patent, the terms “invention”, “present invention” and variations thereof mean one or more embodiment, and are not intended to mean the claimed invention of any particular appended claim(s) or all of the appended claims. Accordingly, the subject or topic of each such reference is not automatically or necessarily part of, or required by, any particular claim(s) merely because of such reference. So long as they are not mutually exclusive or contradictory any aspect or feature or combination of aspects or features of any embodiment disclosed herein may be used in any other embodiment disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-2 illustrate a system 10 according to the present invention which has a container 8; a handling system 4; and an auger 6. Any suitable container or tank of any configuration and dimensions may be used. As shown, the container 8 is an elongated tank for receiving and holding a mixture with liquid and solids. In certain particular aspects, the container 8 is designed so that it can be easily transported from location to location; e.g., land locations, on an offshore platform, or to and from other remote locations.

Optionally, the container 8 has a pair of rails 18 supported by braces 20. The handling system 4, which moves on the rails 18, is mounted on a platform or trolley 22 which has a set of wheels 24. The platform 22 has a pair of sprocket wheels 26 which are propelled by a motor and which engage the rails 18 to move the handling system 4 back and forth from one end of the container 8 to the other.

The handling system 4 includes a shovel 28 for moving material within and from one end to the other end of the container.

The handling system 4 includes a pump system 30 according to the present invention for pumping material from the container 8. The pump system 30 includes at least one pump according to the present invention.

As shown in FIG. 2, the handling system 4 and the shovel 28 have moved within the container 8, pushing material toward one end of the container 8. Here the auger 6 may be activated to move material from the container 8.

FIG. 3 shows shovel 28 connected to a boom ladder 40, extending from a first extension member 42. The boom ladder 40 and the first extension member 42 are pivotally attached by a pin 44. The first extension member 42 is attached to the platform 22. A shovel blade 48 is attached to a second extension member 46. An optional detachable shovel blade 50 is attached to the boom member 40 via a third extension member 52.

The pump system 30 includes a pump motor 54 which is adapted to a pump case cylinder 56. A guard 58 is, optionally, included so that a suction inlet 60 is raised enough off the bottom so that large solids do not enter the pump or block off the suction inlet 60. A disposal conduit 62, leading from the pump case cylinder 56, conducts material to a swivel joint conduit 64 for ultimate disposal. Optionally, an oscillator 70 oscillates the boom ladder 40.

Referring now to FIG. 4, the motor 54 of the pump system 30 is operatively associated with an impeller assembly 200. The pump motor 54 may be any suitable commercially available motor. The shaft from the motor extends to the pump case cylinder 56, with the impeller 200 encased within the pump case cylinder 56. A shaft cover 250 extends from the motor 54 to a top 252 of the pump case cylinder 56. The cover 250 contains supports and a top flange 254 and a bottom flange 256, with the top flange 254 connected to a motor flange 258. Lines for the motor include an input line 260 and output line 262 for hydraulic power fluid input and output.

The disposal conduit 62 leads from the pump case cylinder 56. The pump case cylinder 56 has an extension section 264 that stretches to the generally vertically oriented disposal conduit 62. The extension section 264 also extends to a slurry gate 122 with a passage 124. Brackets 265, 266 are used for mounting the hydraulic motor and legs 58. FIG. 5 depicts the impeller assembly 200 and the protrusion of blade ends from a pump case bottom 267. The slurry gate 122 provides an outlet for the system.

In FIG. 6, the underside portion of the pump system 30 is illustrated and the impeller assembly 200 is shown projecting from the bottom of the pump case. The extension section 264 extends from the cylindrical pump case cylinder 56. The slurry gate 122 contains a rod 268 that is used to position the gate in an open or closed position. Alternatively, an hydraulic cylinder apparatus is used to move the gate. The pump both mixes the slurry and discharges it.

As shown in FIG. 7, a plate 202 is disposed within the pump case cylinder 56. An outer periphery 270 is placed in relatively close relationship with an inner cylindrical wall 272 of the pump case cylinder 56. Material (e.g. mixture; slurry) enters the pump case cylinder 56 from a center inlet area 208 and is directed through the impeller assembly 200 and outward towards the inner wall 272 due to the centrifugal force generated by rotation. Arrows 274 depicted the travel area of the slurry about the inner circular wall 272 to the extension section 264 which in turn allows passage to the disposal conduit 62. The extension section 264 and the disposal conduit 62 are in fluid communication with one another. The material is then lifted by the pump system 30 up into and out of the conduit 62.

FIG. 8 shows the pump system 30 with a rotative shaft 276 that extends from the motor 54. The shaft cover 250 is generally a cylindrical member with an inner bore. The inner bore has disposed therein a first set of roller bearings 278 and second set of roller bearings 280 that are separated by a spacer 282. The shaft 276 is threadedly connected to the impeller assembly 200 so that, when the shaft 276 is rotated by the motor, the impeller assembly 200 and associated blades rotate thereby loading the pump case cylinder 56 with the material as previously described.

A generally circular opening 284 is at the bottom 267 of the case 56. In one aspect, a wear plate 286 is, optionally, added which adds to the structure and reinforces the pump case 56 thereby protecting from the erosional forces produced during pumping. The slurry gate 124 provides a mixing outlet for the material.

The pump system 30 includes a packing structure 170 according to the present invention which may be any packing structure according to the present invention disclosed herein. The packing structure 170 surrounds the shaft 276.

FIGS. 9A and 9B show a pump system 300 according to the present invention which has a driving shaft 332 driven by a motor 334. The driving shaft 332 is connected to an impeller assembly (not shown; any suitable impeller, e.g., but not limited to, like the impeller assembly 200, FIG. 7).

The driving shaft 332 extends through a housing 336 and has a lower threaded end 338 for connection to an impeller assembly. The motor 334 is mounted on a plate 342. Flanges 344 are connected to the housing 336 and a base 346.

A bearing spacer 350 spaces-apart upper bearings 352 and lower bearings 354 which facilitate rotation of the driving shaft 332. Lubricant is contained in a space 356 and encompasses the bearings. This lubricant (e.g. high viscosity lubricant e.g., gear oil) is introduced into the space 356 through a port 358 which is closed off with a plug 362 (e.g. once the space is devoid of air). A removable snap ring 364 holds the bearings 352, 354 and the bearing spacer 350 in place. Lubricant can flow from the port 358 down to the lowest of the lower bearings 354. The space 356 includes the bearings 352, 354 and the open area below the bearings 352 and space above the bearings 354.

A packing structure 310 according to the present invention surrounds the driving shaft 332; maintains the bearings in place; and prevents contaminants from entering the space 356 which could damage or erode parts of the system, e.g. the shaft 332 and/or the bearings.

FIGS. 9C, 10A and 10B show the packing structure 310 in detail. According to the present invention, at least one seal can be used and at least one seal retainer ring can be used. As shown in FIG. 9B and FIG. 9C there are a plurality of seals 311, 312, 313, 314 held in place by retainer rings or “floor members,” a top floor member 316 and a bottom floor member 318. In certain aspects the seals 311-314 are made of hard rubber and steel and the floor members are made of high wear resistant material such as, e.g., 4140 steel. A single floor member may be used. The floor members have cutouts or recesses R for the seals. The floor members 316, 318 are exteriorly threaded and engage interior threading 337a and 337b on the housing 336. A retainer or “hat” 322 is used between the exterior of the shaft 332 and the seals 311-314. A top end of the retainer 322 abuts a shoulder 332a of the shaft 332. The retainer has a base 322b and a cylinder 322c. The cylinder 322c encircles part of the shaft 332. The retainer 322 rotates with the shaft 332. An impeller (e.g. an impeller/assembly as in FIG. 4) will abut the retainer 322, locking it in place and sealing the bearing housing. The retainer 322 acts as a barrier inhibiting or preventing contaminants and debris from contacting the pump shaft.

The upper and lower floors exceed the interior diameter of the bearings and provide housings for the double set of seals that isolate the bearing area. The floor members also act as temporary supports and guides for the shaft 332, e.g. if a bearing failure occurs. This auxiliary back-up support and guidance function allows for the pump operation to continue until a safe shut down can be made for replacement.

To pressurize the seals 311-314 against the shaft 332, grease under pressure is introduced through a grease fitting 324 into the space occupied by the seals 311-314 and the floor members 316, 318. The pressure of this grease, confined about the seals, provides a positive internal pressure at the location of the packing structure 310. This positive internal pressure is greater than atmospheric pressure external to the bearing housing and is greater than an increased external pressure, e.g. such an increased pressure caused by suction created by impeller turbulence. It is within the scope of the present invention to use one, two, three, four, five, six or more of the seals 311-314 and/or to use one, two, three or more of the floor members 316, 318. A seal hammer can be used to install the seals evenly in the floor members.

FIG. 11 shows a seal member 360 which has a body 326 with a rubber ring 364 in a recess 366. In one aspect, the seal member 360 is used with the rubber ring 364 facing upwardly. The seal 311 prevents bearing lubricant from flowing down into the packing system 300. Any suitable seal may be used instead of the seal members 360.

The present invention, therefore, provides in at least certain embodiments, a pumping system for pumping a drilling mixture containing liquid drilling fluid and solids entrained in the liquid drilling fluid, the pumping system including: a container for receiving and holding the drilling mixture; centrifugal pump apparatus for transferring the drilling mixture from the container; the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft; a housing, the housing which is an enclosed non-vented structure; and the packing structure, bearing apparatus and part of the pump shaft within the housing. Such a system may have one or some, in any possible combination, of the following: seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing; a lubricant port through the housing for providing lubricant to the bearing apparatus; lubricant within the housing for lubricating the bearing apparatus, the lubricant expandable upon heating to increase pressure within the housing to inhibit contaminants from entering the housing through the pump-shaft/housing interface; the seal apparatus containing at least one seal; the packing structure surrounding the pump shaft and maintaining the bearing apparatus in position adjacent the pump shaft and above the packing structure; the packing structure inhibiting contaminants from flowing to the bearing apparatus; a retainer with a base and a cylinder, the cylinder encircling a portion of the drive shaft and the base abutting a bottom of the packing structure; the retainer acting as a barrier inhibiting contaminants from contacting the pump shaft; seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing, the seal apparatus including at least one seal, and the at least one seal sealingly contacting an exterior surface of the retainer ring's cylinder; the packing structure including at least one seal, and at least one retainer ring for holding the seal in a sealing position; the at least one retainer ring having a ring diameter, the bearing apparatus having a bearing diameter, and the ring diameter greater than the bearing diameter; impeller apparatus on the pump shaft, the impeller apparatus abutting the retainer; the retainer supporting and guiding the pump shaft in the event of failure of the bearing apparatus; a grease port for introducing grease into the housing for the at least one seal of the seal apparatus; and/or grease adjacent the at least one seal, the grease under pressure to provide a positive internal pressure at a location of the packing structure.

The present invention, therefore, provides in at least certain embodiments, a pumping system for pumping a drilling mixture containing liquid drilling fluid and solids entrained in the liquid drilling fluid, the pumping system including: a container for receiving and holding the drilling mixture; centrifugal pump apparatus for transferring the drilling mixture from the container; the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft; a housing which is an enclosed non-vented structure; the packing structure, bearing apparatus and part of the pump shaft within the housing; seal apparatus for sealing the housing to prevent the ingress of contaminants into the housing; the packing structure surrounding the pump shaft and maintaining the bearing apparatus in position adjacent the pump shaft and above the packing structure; the packing structure inhibiting contaminants from flowing to the bearing apparatus; a retainer with a base and a cylinder, the cylinder encircling a portion of the drive shaft and the base abutting a bottom of the packing structure; and the retainer acting as a barrier inhibiting contaminants from contacting the pump shaft.

The present invention, therefore, provides in at least certain embodiments, a centrifugal pump apparatus including: a pump shaft; a motor to drive the pump shaft; a packing structure around the pump shaft; bearing apparatus around the pump shaft; a housing which is a non-vented housing; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

The present invention, therefore, provides in at least certain embodiments, a method for pumping a mixture containing liquid and solids, the method including: feeding the mixture from a container for receiving and holding the mixture to a centrifugal pump apparatus for transferring the mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a housing, a packing structure around the pump shaft and bearing apparatus around the pump shaft, the housing comprising a non-vented housing, the packing structure, bearing apparatus and part of the pump shaft within the housing; and, with the centrifugal pump, pumping the mixture from the container.

The present invention, therefore, provides in at least certain embodiments, a pumping system for pumping a mixture containing liquid and solids, the pumping system including: a container for receiving and holding the mixture; centrifugal pump apparatus for transferring the mixture from the container; the centrifugal pump apparatus including housing, a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, the housing being a non-vented enclosure; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein and those covered by the appended claims are well adapted to carry out the objectives and obtain the ends set forth. Certain changes can be made in the subject matter without departing from the spirit and the scope of this invention. It is realized that changes are possible within the scope of this invention and it is further intended that each element or step recited in any of the following claims is to be understood as referring to the step literally and/or to all equivalent elements or steps. The following claims are intended to cover the invention as broadly as legally possible in whatever form it may be utilized. The invention claimed herein is new and novel in accordance with 35 U.S.C. § 102 and satisfies the conditions for patentability in § 102. The invention claimed herein is not obvious in accordance with 35 U.S.C. § 103 and satisfies the conditions for patentability in § 103. This specification and the claims that follow are in accordance with all of the requirements of 35 U.S.C. § 112. The inventors may rely on the Doctrine of Equivalents to determine and assess the scope of their invention and of the claims that follow as they may pertain to apparatus not materially departing from, but outside of, the literal scope of the invention as set forth in the following claims. All patents and applications identified herein are incorporated fully herein for all purposes. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.