HIGH-CAPACITY FLUID PUMP

Abstract

A high-capacity fluid pump comprising a dedicated lubrication system in fluid communication with the pump's drive assembly to reduce wear of internal components within the gearbox, as well as a drive shaft-supported impeller and outboard head to reduce deflection. Moreover, the blades of the outboard head are preferably shaped to decrease the inlet's cross section and stabilize incoming fluid, thereby reducing cavitation, pre-rotation, and turbulent flow at the pump inlet and increasing the overall velocity of incoming fluid.

Claims

1. A high-capacity water pump comprising: a. a drive assembly comprising a drive shaft operatively coupled to a gearbox., wherein the gearbox comprises a plurality of gears; b. a fluid pump assembly operatively coupled to the drive assembly, the fluid pump assembly comprising: a volute, an outboard head attached to the volute, and an impeller positioned within the volute and coupled to the drive shaft; c. a lubrication system in fluid communication with the gearbox, the lubrication system comprising: an oil pump; a plurality of gearbox inlet nozzles each positioned proximate to one of the plurality of gears; and a plurality of hoses connecting the oil pump to the plurality of gearbox inlet nozzles.

2. The pump of claim 1, wherein the lubrication system further comprises a splitter, the splitter operatively connecting the oil pump to the plurality of hoses.

3. The pump of claim 2, wherein the lubrication system further comprises a cooler, the cooler operatively connecting the oil pump to the splitter.

4. The pump of claim 1, wherein the outboard head comprises an annular inlet subdivided into a plurality of apertures by a plurality of fixed blades extending from a central nose, the central nose comprising a cavity.

5. The pump of claim 4, wherein a distal end of the drive shaft extends into the cavity of the central nose, and wherein the drive assembly further comprises a sacrificial bushing mounted to the distal end of the drive shaft.

6. A pump comprising: a. a drive assembly comprising a drive shaft operatively coupled to a gearbox, wherein the gearbox comprises one or more gears; b. a lubrication system in fluid communication with the drive assembly, wherein the lubrication system comprises a lubricant pump; and c. a fluid pump assembly comprising a head with an inlet, wherein the head further comprises at least one blade extending from a central nose and dividing the inlet into at least two apertures, and wherein a distal end of the drive shaft extends into a cavity formed in the central nose.

7. (canceled)

8. The pump of claim 6, wherein the lubrication system further comprises one or more gearbox inlet nozzles positioned proximate to the one or more gears.

9. The pump of claim 8, wherein the lubrication system further comprises one or more hoses connecting the lubricant pump to the one or more gearbox inlet nozzles.

10. The pump of claim 6, wherein the drive assembly further comprises a sacrificial bushing mounted to the distal end of the drive shaft.

11. A pump comprising: a. a drive assembly comprising a drive shaft; b. a lubrication system in fluid communication with the drive assembly, wherein the lubrication system comprises a lubricant pump; and c. a fluid pump assembly comprising a head with an inlet, wherein the head comprises: i. at least one blade dividing the inlet into at least two apertures, and; ii. a cavity shaped to house a rotatable sacrificial bushing, wherein the drive shaft is attached to the sacrificial bushing.

12. (canceled)

13. (canceled)

14. (canceled)

15. The pump of claim 11, wherein the at least one blade has a length in a direction orthogonal to a plane of the inlet for reducing pre-rotation of fluid around a central axis of the inlet.

16. The pump of claim 11, wherein the fluid pump assembly further comprises an impeller positioned on the drive shaft between a biasing member and a support member, and wherein the impeller is positioned on the drive shaft such that the biasing member is at least partially compressed.

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, and which, together with the detailed description below, are incorporated in and form part of the specification, serve to illustrate further various embodiments and to explain various principles and advantages in accordance with the present invention:

[0025] FIG. 1 is a front perspective view of one embodiment of a pump in a split drive configuration.

[0026] FIG. 2 is a rear perspective view of the pump of FIG. 1.

[0027] FIG. 3 is an exploded view of the pump of FIG. 1.

[0028] FIGS. 4A-B are lubricant flow diagrams.

[0029] FIG. 4C is a coolant flow diagram.

[0030] FIG. 5 is a front perspective view of one embodiment of a pump in a direct drive configuration.

[0031] FIG. 6 is a rear perspective view of the pump of FIG. 5.

[0032] FIG. 7A is an exploded view of one embodiment of an output drive assembly and fluid pump assembly.

[0033] FIGS. 7B-C are front and rear views of the outboard head of FIG. 7A.

[0034] FIG. 7D is a detail view of FIG. 7C.

[0035] FIG. 8 is a cross section of one embodiment of a fluid pump assembly.

DESCRIPTION OF REFERENCE NUMERALS

[0036] 100 . . . high-capacity pump

[0037] 150 . . . motor

[0038] 160 . . . tank

[0039] 200 . . . drive assembly

[0040] 205 . . . gearbox

[0041] 210 . . . pressure release valve

[0042] 220 . . . front input drive

[0043] 221 . . . input drive housing

[0044] 222 . . . input drive gear

[0045] 223 . . . input drive cap

[0046] 230 . . . transmission assembly

[0047] 232 . . . transmission shifter

[0048] 234 . . . transmission shaft

[0049] 240 . . . accessory drive

[0050] 241 . . . accessory drive cap

[0051] 242 . . . accessory drive gear

[0052] 250 . . . upper output drive

[0053] 251 . . . upper output drive cap

[0054] 252 . . . upper output gear

[0055] 253 . . . upper output bearing assembly

[0056] 254 . . . drive shaft

[0057] 254a . . . threaded portion of drive shaft 254

[0058] 255 . . . nut

[0059] 260 . . . idler gear

[0060] 270 . . . lower output drive

[0061] 300 . . . lubrication system

[0062] 302 . . . gearbox inlet port

[0063] 303 . . . gearbox outlet port

[0064] 304 . . . hose

[0065] 310 . . . lubricant pump

[0066] 312 . . . lubricant pump inlet hose

[0067] 314 . . . lubricant pump outlet hose

[0068] 316 . . . lubricant collection container

[0069] 318 . . . lubricant filter

[0070] 320 . . . directional port

[0071] 330 . . . splitter

[0072] 332 . . . pressure sensor

[0073] 333 . . . pressure sensor line

[0074] 334 . . . pressure gauge

[0075] 340 . . . cooler

[0076] 342 . . . cooler inlet hose

[0077] 344 . . . cooler outlet hose

[0078] 346 . . . cooler inlet port

[0079] 348 . . . cooler outlet port

[0080] 400 . . . fluid pump assembly

[0081] 410 . . . inboard head

[0082] 420 . . . impeller

[0083] 430 . . . volute

[0084] 432 . . . pump outlet

[0085] 433 . . . aperture for cooler outlet hose 344

[0086] 440 . . . outboard head

[0087] 442 . . . central support member

[0088] 443 . . . first side (curved), nose

[0089] 444 . . . sacrificial bushing

[0090] 445 . . . blade

[0091] 446 . . . first side (curved)

[0092] 447 . . . second side (flat)

[0093] 448 . . . aperture for fluid entering volute 430

[0094] 450 . . . O-ring

[0095] 452 . . . gasket

[0096] 454 . . . wear ring

[0097] 456 . . . biasing member

[0098] 457 . . . seal

DESCRIPTION

[0099] A high-capacity fluid pump featuring a dedicated lubrication system and stabilized fluid pump assembly components is described herein. The description which follows, and the embodiments described therein, is provided, by way of illustration of examples of particular embodiments of principles and aspects of the present invention. These examples are provided for the purposes of explanation and not of limitationof those principles of the invention. In the description that follows, like parts are marked throughout the specification and the drawings with the same respective reference numerals. As used herein, the term “about” or “approximately” applies to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these temis may include numbers that are rounded to the nearest significant figure. Relational terms such as first and second, top and bottom, right and left, and the like may be used solely to distinguish one component or feature from another component or feature without necessarily requiring or implying any actual such relationship or order between such components and features.

[0100] A high-capacity pump 100 designed according to this disclosure may benefit from reduced wear and increased efficiency. Pump 100 may comprise a drive assembly 200, lubrication system 300, and fluid pump assembly 400.

[0101] A dedicated lubrication system 300 can help reduce wear in a drive assembly 200. Lubrication system 300 preferably pumps lubricant directly on or proximate to gears, bearings, and other moving parts within drive assembly 200. If lubrication system 300 comprises a lubrication collection container 316, such as an oil pan, splash lubrication can operate in parallel with the lubrication system 300 and acts as a backup. Optimal lubrication can reduce wear and promote uniformity of wear across components while increasing their useful life. A lubrication system 300 comprising a cooler 340 can further reduce wear-inducing temperatures and prevent lubricant degradation.

[0102] Wear may be further reduced within an adequately supported and stabilized fluid pump assembly 400. As shown in FIGS. 7A and 8, fluid pump assembly 400 comprises an impeller 420 and outboard head 440. In one embodiment, impeller 420 is rotated by a drive shaft 254, which has a threaded portion 254a. Impeller 420 is positioned on drive shaft 254 between a biasing member 456 and a nut 255, which engages threaded portion 254a. Because nut 255 has a greater outer diameter than an inner diameter of the impeller 420, tensioning nut 255 loads (e.g., compresses) biasing member 456 and thereby stabilizes the impeller 420, preventing deflection. In this or an alternative embodiment, drive shaft 254 also supports and stabilizes outboard head 440. Head 440 comprises central support member 442 housing a sacrificial bushing 444 that is engaged to the threaded portion 254a.

[0103] Increased efficiency may be achieved by increasing laminar flows of fluid across the inlet of fluid pump assembly 400. In one embodiment, the outboard head 440 comprises one or more blades 445 that prevent pre-rotation of fluid entering the inlet. In some forms, central support member 442 comprises a nose member 443 that is curved and to which blades 445 are connected. Blades 445 may also have a curved side 446 facing fluid entering the inlet, reducing drag.

[0104] Turning to the figures, FIGS. 1 and 2 show one form of a high-capacity pump 100 in a split drive configuration suitable for installation on a fire apparatus (not shown), e.g., a fire truck. The pump 100 comprises a drive assembly 200, a lubrication system 300, and fluid pump assembly 400.

[0105] The split drive configured drive assembly 200 is shown in an exploded view in FIG. 3. The motor of a fire apparatus (not shown) may be operably coupled to front input drive 220 to rotate input drive gear 222. Transmission assembly 230, including transmission shifter 232 and transmission shaft 234, causes the input drive gear 222 to engage either lower output drive 270, accessory drive gear 242, or idler gear 260. Lower output drive 270 may be operably coupled to an axle (not shown) to turn the wheels of a fire apparatus. The accessory drive 240 is optional and may be coupled to a shaft (not shown) or other device to operate fire apparatus accessories, such as a hydraulic pump to drive a foam system or air compressor. Because idler gear 260 may engage both input drive gear 222 and upper output gear 252, it is preferably sized to optimize the operation of fluid pump assembly 400. (This gear ratio is a function of the horsepower of the motor and the operational requirements of the fluid pump assembly 400.) Upper output gear 252 rotates drive shaft 254.

[0106] The drive assembly 200 may also comprise a gearbox 205. The gearbox 205 is preferably sealed such that a pressure within gearbox 205 may be greater than atmospheric pressure. The gearbox 205 may comprise pressure release valve 210, accessory drive cap 241, and upper output drive cap 251.

[0107] One form of a lubrication system 300, shown in FIGS. 1-3 and 4A, comprises an oil pump 310. Oil pump 310 is directly connected to splitter 330, which distributes pressurized lubricant across hoses 304. The lubrication system 300 also comprises an oil filter 318 (not shown) positioned in or in fluid communication with an oil pan 316 (not shown).

[0108] Another form of a high-capacity pump 100, shown in FIGS. 5-6, may be in a direct drive configuration suitable for stationary or mobile applications with a dedicated motor 150. The pump 100 comprises a drive assembly 200, a lubrication system 300, and fluid pump assembly 400.

[0109] The drive assembly 200 comprises a gearbox 205, an input drive 220, a gear 260, and an output drive 250. The size of gear 260 is a function of the horsepower of the motor and the operational requirements of the fluid pump assembly 400. The gearbox comprises an input drive housing 221, an input drive cap 223, and an output drive cap 251.

[0110] As shown in FIGS. 5-6 and 4B-C, another form of a lubrication system 300 comprising an oil pump 310 and a cooler 340. Oil pump 310 is connected to cooler 340, which is connected to splitter 330. In this embodiment, cooler 340 circulates water and is connected to water tank 160 and water pump outlet 432. The lubrication system 300 also comprises an oil filter 318 (not shown) positioned in or in fluid communication with an oil pan 316 (not shown).

[0111] If an oil pump 310 is located outside gearbox 205 as shown in FIGS. 1-3 and 5-6, the gearbox 205 may also comprise apertures for gearbox inlet nozzles 302 and gearbox outlet nozzles 303. The apertures for gearbox inlet nozzles 302 are preferably positioned at or near gears or other moving parts of drive assembly 200. The aperture for gearbox outlet nozzle 303 is preferably positioned near a lubrication collection container, such as an oil pan.

[0112] For example, as shown in FIGS. 1-3, the gearbox 205 comprises seven apertures for gearbox inlet nozzles 302 located proximally to front input drive 220 (one aperture), accessory drive 240 (one aperture), upper output drive 250 (three apertures), idler gear 260 (hidden, one aperture), and lower output drive 270 (one aperture). By contrast, FIGS. 5-6 shows gearbox 205 with five apertures for gearbox inlet nozzles 302 located proximally to an output drive (three apertures), idler gear 260 (hidden, one aperture), an input drive cap 223 (one aperture).

[0113] Forms of the fluid pump assembly 400 are shown in 1-2, 5-6, 7A-D and 8 and are suitable for both split drive, direct drive, and other configurations. As shown in FIGS. 7A and 8, a fluid pump assembly 400 may comprise an inboard head 410, an impeller 420, a volute 430, and an outboard head 440.

[0114] One way to couple a drive assembly 200 to a fluid pump assembly 400 is through the attachment of upper output bearing assembly 253 to inboard head 410. Mechanical seal 457 preferably forms a fluid impermeable seal between fluid pump assembly 400 and drive assembly 200, preventing water or other fluid from entering drive assembly 200 and preventing lubricant from entering fluid pump assembly 400. Seal 457 is a wear component that should be replaced from time to time.

[0115] Gaskets 452 and O-rings 450 seal attachments between the volute 430 and inboard head 410 and outboard head 440. Wear rings 454 are positioned between the impeller 420 and inboard head 410 and outboard head 440. Wear rings 454 are wear components that should be replaced from time to time.

[0116] Drive shaft 254 rotates impeller 420. Drive shaft 254 comprises a non-threaded portion (which may comprise a notch to engage impeller 420) and a threaded portion (254a). A biasing member 456, such as a spring, may be positioned on the non-threaded portion proximate to inboard head 410. Nut 255 may engage threaded portion 254a of drive shaft 254 proximate to outboard head 440. Impeller 420 may be positioned between and abut biasing member 456 and nut 255, such that tightening nut 255 loads biasing member 456 and stabilizes impeller 420. Nut 255 may be a jack nut and is preferably formed from a material that is softer than the material composing the impeller 420; for example, if impeller 420 is steel, nut 255 may be brass.

[0117] As shown in FIGS. 2 and 7B-D, outboard head 440 has a first side and second side. On the first side of outboard head 440, best seen in FIGS. 2 and 7C-D, head 440 comprises an inlet of three apertures 448. The inlet is defined by an inner diameter of the outboard head 440 divided by a central support member 442 (with a curved nose 443) connected to three blades 445, each preferably having a substantially curved side 446.

[0118] On the second side of outboard head 440, as shown in FIG. 7B, the central support member 442 has a cavity that houses a sacrificial bushing 444. The second side 447 of blades 445 are preferably substantially flat (i.e., not curved). Onboard head 440 is attached to volute 430 and sacrificial bushing 444 is attached to threaded portion 254a of drive shaft 254.

[0119] Sacrificial bushing 444 supports outboard head 440 and prevents deflection of the fluid pump assembly 400. Sacrificial bushing 444 rotates with drive shaft 254 and a thin film of fluid separates it from central support member 442. Sacrificial bushing 444 is preferably formed from a material that is softer than the material composing the central support member 442; for example, if central support member 442 is steel, sacrificial bushing 444 may be brass.

[0120] Blades 445 prevent pre-rotation of fluid entering the inlet of outboard head 440 and promote laminar flow across the inlet and into the impeller 420. Blades 445 preferably have a length equal to or less than the length of outboard head 440 (measured along its central axis).

[0121] Various founs of the invention may have various flow paths for fluids moving through or within the high-capacity pump 100, including fluid moving through fluid pump assembly 400, lubricant moving within drive assembly 200 and lubrication system 300, and/or coolant moving through cooler 340.

[0122] One method of moving fluid through a high-capacity pump 100 comprises rotating an impeller 420. Impeller 420 creates low pressure at an inlet of fluid pump assembly 400 (within head 440), causing fluid to move from a tank 160 through the inlet and into impeller 420. Impeller 420 accelerates the fluid by applying a centrifugal force on the fluid within a volute 430. Fluid exits at high speed and pressure at pump outlet 432 (within volute 430).

[0123] One method of moving lubricant within drive assembly 200 comprises pumping lubricant from an oil pan 316. In one embodiment, see FIG. 4A, oil pump 310 draws lubricant through filter 318 positioned in or in fluid communication with oil pan 316, out gearbox outlet port 303, through oil pump 310, across one or more gearbox inlet ports 302, and into gearbox 205. In another embodiment, see FIG. 4B, oil pump 310 draws lubricant through filter 318 positioned in or in fluid communication with oil pan 316, out gearbox outlet port 303, through oil pump 310, cooler 340, and splitter 330, across one or more gearbox inlet ports 302, and into gearbox 205. In both embodiments, once within the gearbox 205, the lubricant lubricates gears, bearings, and other moving parts until the lubricant flows to oil pan 316 and the cycle is repeated. Splash lubrication may proceed concurrently with the lubrication system 300. As shown in FIGS. 1-2 and 5-6, lubricant may also move through directional port 320, pump inlet hose 312, pump outlet hose 314, splitter 330 and/or cooler 340.

[0124] One method of moving coolant, such as water or other suitable fluid, through a lubrication system 300 comprises pumping coolant and lubricant across a heat exchanger within a cooler 340. In one embodiment, see FIG. 4C, coolant may flow from tank 160, through cooler 340, and out pump outlet 432. In another embodiment, see FIGS. 5-6, water may flow from tank 160, into cooler inlet port 346, through cooler inlet hose 342, across a heat exchanger to absorb heat from the lubricant, through cooler outlet hoses 344, and out cooler outlet port 348 to pump outlet 432.

PROPHETIC EXAMPLE 1

[0125] In a split drive configuration (see FIGS. 1-3, 7A-D, and 8), about 5000 to 6500 gal./min. flows through fluid pump assembly 400, entering through outboard head 440, and exiting through pump outlet 432. A fire apparatus with about 600 to 700 horsepower rotates—through drive assembly 200 and front input drive 220—impeller 420, which has an angular velocity of about 2000 to 2400 rotations per minute. Lubrication system 300 is in fluid communication with drive assembly 200 and operates at pressures ranging from about 15 to 30 psi.

PROPHETIC EXAMPLE 2

[0126] In a direct drive configuration (see FIGS. 5-8), about 5000 to 6500 gal./min. flows through fluid pump assembly 400. An engine 150 with about 600 to 800 horsepower engages—through drive assembly 200—impeller 420, which has an angular velocity of about 2000 to 2400 rotations per minute. Lubrication system 300 is in fluid communication with drive assembly 200 and operates at pressures ranging from about 15 to 30 psi.

PROPHETIC EXAMPLE 3

[0127] In either or both of the foregoing examples, lubrication system 300 may also comprise cooler 340 to maintain operating lubrication temperatures below about 180° F.

[0128] Many components described in this disclosure may be optional, regardless of whether they are identified as such. For illustrative purposes, however, some components may be optional or unnecessary depending on the application for which the pump 100 will be used.

[0129] For example, unlike the drive assembly 200 of FIGS. 1-3, the drive assembly 200 of FIGS. 5-6 does not have an accessory drive 240, a lower output drive 270, or a transmission assembly 230. These are optional components for certain applications.

[0130] Likewise, some lubrication systems 300 may not comprise a splitter 330 (see FIG. 4A) or a filter 318. Further, in some embodiments, all or part of the lubrication systems 300 may be located within a gearbox 205, eliminating the need for gearbox inlet ports 302 and gearbox outlet port 303.

[0131] While specific embodiments have been described above, many alternative embodiments may be suitable in view of the objects of the foregoing disclosure.

[0132] Although the pump 100 lends itself to large-scale industrial firefighting applications, it could also be used in a municipal setting.

[0133] In alternative embodiments, each drive component with a single aperture for a gearbox inlet port 302 may have plural apertures for plural ports 302. Alternatively, a drive component having plural apertures for plural ports 302 may only have one at that location on the gearbox 205; in which case, the single gearbox inlet port 302 preferably has a wide spraying nozzle to maximize distribution of lubricant within gearbox 205.

[0134] Numerous modifications, substitutions, and omissions may be made to the order of flow within a lubrication system 300. For example, filter 318 may be located outside gearbox 205; FIG. 4A would be modified to show: 205.fwdarw.316.fwdarw.303.fwdarw.318.fwdarw.310.fwdarw.302.fwdarw.205. Numerous alternative orders exist and all are within the scope of this disclosure. Indeed, directional ports 320, splitters 330, and coolers 340 may be interposed almost anywhere between an oil pump 310 and gearbox 205; or they may be omitted.

[0135] Under appropriate conditions, all or part of the lubrication systems 300 of either of the illustrative high-capacity pumps 100 shown may be substituted for the other. For example, the lubrication system 300 of FIGS. 1-3 (without cooler and/or additional hoses 304) may be substituted with suitable modifications for the lubrication system 300 of FIGS. 5-6 (with cooler 340 and/or fewer hoses 304) for the high-capacity pump 100 of FIGS. 5-6. And vice versa.

[0136] Cooler 340 may circulate a fluid other than water, such as radiator fluid, refrigerant, or other suitable fluid.

[0137] Any container suitable for holding oil or other lubricant may serve as an oil pan or lubrication collection pan or container, including a portion of the gearbox 205 itself.

[0138] Blades 445 may have two flat sides, two curved sides, or some blades may have curved or flat sides while others may or may not.

[0139] Finally, many fluid pumps (including high, regular, and smaller capacity pumps) may be retrofitted with all or part of lubrication system 300, and/or with all or some of the components supporting and stabilizing the fluid pump assembly 400, and/or an inlet with one or more blades 445. One of ordinary skill with the benefit of this disclosure would know what modifications, if any, would be necessary to retrofit such existing or future developed systems.

[0140] The foregoing description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form(s) disclosed, and many modifications and other embodiments of the invention set forth in this disclosure will be appreciated by one skilled in the art having the benefit of this disclosure. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. The embodiments shown in the drawings and described above are exemplary of numerous embodiments that may be made within the scope of the appended claims. It is contemplated that numerous other configurations may be used, and the material of each component may be selected from numerous materials other than those specifically disclosed.

[0141] It will be appreciated that in the development of a product or method embodying the invention, the developer must make numerous implementation-specific decisions to achieve the developer's specific goals, such as compliance with manufacturing and business-related constraints, that will vary from one implementation to another. Moreover, it will be appreciated that such a development effort may be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

[0142] This disclosure does not contain a glossary. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. Words and phrases should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art and case law. For example, an embodiment comprising a singular element does not disclaim plural embodiments; i.e., the indefinite articles “a” and “an” carry either a singular or plural meaning and a later reference to the same element reflects the same potential plurality. A structural element that is embodied by a single component or unitary structure may be composed of multiple components. Ordinal designations (first, second, third, etc.) merely serve as a shorthand reference for different components and do not denote any sequential, spatial, or positional relationship between them. Words of approximation such as “about,” “approximately,” or “substantially” refer to a condition or measurement that, when so modified, is understood to not necessarily be absolute or perfect but would be considered close enough by those of ordinary skill in the art to warrant designating the condition as being present or the measurement being satisfied. For example, a numerical value or measurement that is modified by a word of approximation, such as “about” or “approximately,” may vary from the stated value by 1, 2, 3, 4, 5, 6, 7, 10, 12, and up to 15%.

[0143] It is intended that the scope of the invention be defined only by the following claims, as amended, and their equivalents.