Removable Packing Gland Assembly

The present disclosure relates generally to fluid pumps and, for example, to a removable packing gland assembly.

Hydraulic fracturing is a well stimulation technique that typically involves pumping hydraulic fracturing fluid into a wellbore at a rate and a pressure (e.g., up to 15,000 pounds per square inch (psi)) sufficient to form fractures in a rock formation surrounding the wellbore. This well stimulation technique often enhances the natural fracturing of a rock formation to increase the permeability of the rock formation, thereby improving recovery of water, oil, natural gas, and/or other fluids.

Positive displacement pumps are commonly used for high pressure hydrocarbon recovery applications, such as injecting hydraulic fracturing fluid down the wellbore. A positive displacement pump typically has two sections, a power end and a fluid end. The power end includes a crankshaft powered by an engine or another power source that drives plungers of the fluid end. The fluid end includes cylinders into which the plungers operate to allow fluid into fluid chambers and then forcibly push out from the fluid chambers at a high pressure to a discharge manifold, which may be in fluid communication with a well head. A seal assembly, also called a packing, packing assembly, or stuffing box, may be disposed in a packing bore of a cylinder chamber to prevent leakage of fluid from around a plunger during pumping operations. Over time, the packing bore may experience excessive wear due to high applied pressures and reciprocation of the plunger, which can lead to leaks and/or failure of the packing bore. Repair of the packing bore is difficult, and in cases of severe wear, the entire fluid end may be replaced.

The removable packing gland assembly of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.

A fluid end for a fluid pump may include a fluid end block defining a fluid chamber and a packing gland assembly. The packing gland assembly may include a packing gland housing, interfaced with the fluid chamber, defining a bore extending from a front end to a rear end of the packing gland housing. The packing gland housing may include a flange having a front face, that defines the front end of the packing gland housing, and a rear face. The flange may define a plurality of apertures that extend from the front face of the flange to the rear face of the flange. The packing gland housing may include a mating neck extending from the flange to rear end of the packing gland housing. The mating neck may define a stepped circumferential surface having one or more steps, and may define a circumferential groove. The packing gland assembly may include a sealing ring disposed in the circumferential groove, and a plurality of fasteners extending through the plurality of apertures and into the fluid end block to connect the packing gland housing to the fluid end block.

A packing gland assembly may include a packing gland housing defining a bore extending from a front end to a rear end of the packing gland housing. The packing gland housing may include a flange having a front face, that defines the front end of the packing gland housing, and a rear face. The flange may define a plurality of apertures that extend from the front face of the flange to the rear face of the flange. The packing gland housing may include a mating neck extending from the flange to the rear end of the packing gland housing. The mating neck may define a stepped circumferential surface having one or more steps, and may define a circumferential groove.

A fluid pump may include a power end and a fluid end coupled to the power end. The fluid end may include a fluid end block defining a fluid chamber and a packing gland assembly. The packing gland assembly may include a packing gland housing, interfaced with the fluid chamber, defining a bore extending from a front end to a rear end of the packing gland housing. The packing gland housing may include a flange defining a plurality of apertures, and a mating neck extending from the flange. The mating neck may define a stepped circumferential surface having one or more steps, and may define a circumferential groove. The mating neck may have a face that defines the rear end of the packing gland housing, and the face of the mating neck may directly abut against the fluid end block. The packing gland assembly may include a sealing ring disposed in the circumferential groove, and a plurality of fasteners extending through the plurality of apertures and into the fluid end block to connect the packing gland housing to the fluid end block.

This disclosure relates to a removable packing gland assembly, which is applicable to any reciprocating pump. For example, the reciprocating pump may be used in a hydraulic fracturing application.

is a cross-sectional view of an example prior art fluid endof a fluid pump.shows a top half of the cross-sectional view; a bottom half of the cross-sectional view may be identical or similar to the top half. As shown, the fluid endincludes a fluid cylinder, a packing glandconnected to the fluid cylinderby one or more bolts, and a plungerconfigured to reciprocate within the fluid cylinderand the packing gland. The plungerincludes a plunger pilot, and a plunger or pony rod clamp shoulder.

Packing, including a lantern ring, a female adapter, a peek adapter, a pressure ring, a header ring, and/or a steel spacer, is disposed within the packing glandaround the plunger. A packing nutis secured to an interior surface of the packing glandand maintains the packing in a proper position. A wiper sealis positioned between the packing nutand the plunger. The packing glandincludes a lube oil or grease inletto lubricate the packing.

A sealing D-ringis positioned between the packing glandand the fluid cylinderto seal fluid in the fluid cylinder. A steel pressure ringis positioned in a gap between the packing glandand the fluid cylinderto further seal fluid in the fluid cylinder.

is a diagram illustrating a cross-sectional view of an example fluid pump. In some implementations, the fluid pumpmay be mounted on a trailer to facilitate transportation of the fluid pumpbetween operational sites. The fluid pumpmay be a reciprocating pump, as shown.

The fluid pumpincludes a power endand a fluid endhaving a fluid end block. The fluid endmay be connected to the power endby stay rods. The fluid end blockdefines one or more fluid chambers(only one shown). For example, the fluid pumpmay include one, two, three, four, five, or more fluid chambersand associated components. A fluid chambermay sometimes be referred to as a “bore” of the fluid pump.

The fluid pumpincludes a suction valvethat is configured to control fluid suction into the fluid chamber. Similarly, the fluid pumpincludes a discharge valvethat is configured to control fluid discharge from the fluid chamber. During a suction stroke of a plunger, fluid is allowed to flow from a suction manifoldthrough the suction valveand into the fluid chamber. The fluid is then pumped in response to a discharge stroke (e.g., a forward stroke) of the plungerand flows through the discharge valveinto a discharge port. The discharge portmay be fluidly coupled to a wellbore to supply high pressure fluid to the wellbore for fracturing rock formations and other uses. In operation, the reciprocating plungermoves in a plunger boreand is driven by the power endof the fluid pump.

The power endmay include a crankshaftthat is rotated by a gearbox output(illustrated by a single gear, but may be more than one gear). A gearbox inputis coupled to a transmission (not shown) and a power source (not shown), such as a diesel engine, to rotate the gearbox inputduring operation. A connecting rodmechanically connects the crankshaftto a crossheadvia a wrist pin end. The crossheadis mounted within a stationary crosshead housing, which constrains the crossheadto linear reciprocating movement. A pony rodconnects to the crossheadand has its opposite end connected to the plungerto enable reciprocating movement of the plunger. The plungermay be one of a plurality of plungers, such as, for example, three or five plungers, depending on the size of the fluid pump(e.g., three cylinder, five cylinder, etc.) and the number of fluid chambers.

The plungerextends through the plunger boreso as to interface and otherwise extend within the fluid chamber. In operation, movement of the crankshaftcauses the plungerto reciprocate within, or move linearly toward and away from, the fluid chamber. As the plungertranslates away from the fluid chamber(a suction stroke of the plunger), the pressure of the fluid inside the fluid chamberdecreases, which creates a pressure differential across the suction valve. The pressure differential across the suction valveenables actuation (e.g., opening) of the suction valveto allow the fluid to enter the fluid chamberfrom the suction manifold(e.g., the fluid is pressurized to a low pressure, such as 80 psi, by an outside system, such as a centrifugal pump, and pushed through the suction manifold). The pumped fluid is pushed into the fluid chamberas the plungercontinues to translate away from the fluid chamber. As the plungerchanges directions and moves toward the fluid chamber(a discharge stroke of the plunger), the fluid pressure inside the fluid chamberincreases, which creates a pressure differential across the discharge valve. Fluid pressure inside the fluid chambercontinues to increase as the plungerapproaches the fluid chamberuntil the pressure differential across the discharge valveis great enough to actuate (e.g., open) the discharge valveand enable the fluid to exit the fluid chamber.

A packing gland housingis connected to the fluid end blockinterfacing with the fluid chamber. A packingis disposed in a packing bore of the packing gland housingand surrounds the plunger, which extends through the packing gland housing. A packing nutis threaded into the packing gland housing, and acts to retain the packingin the proper position within the packing bore. When properly positioned, the packingand the packing nutmaintain the necessary pressure between the plungerand the packing, and prevent the packing bore from leaking. In some implementations, a replaceable sleeve or liner may be positioned in the packing bore interfacing with the packing.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating a perspective view of an example fluid endof the fluid pump. As shown, the fluid endincludes a fluid end blockand one or more packing gland assembliesconnected to the fluid end block. For example, as shown, five packing gland assembliesmay be connected to the fluid end block, one at each fluid chamber(e.g., one at each cylinder) of the fluid end block. However, the fluid endmay include a different number of packing gland assemblies(e.g., three packing gland assemblies), depending on the size of the fluid pump(e.g., three cylinder, five cylinder, etc.) and the number of fluid chambers.

A packing gland assemblymay include a packing gland housingand/or a packing nutsecured to (e.g., threaded into) the packing gland housing. A plurality of holesmay be located along a rim of the packing nut, which may be used to tighten or loosen the packing nutwith respect to the packing gland housing. In some implementations, the packing gland assemblymay include a nut lockconfigured to engage with the packing nut, thereby restricting rotation of the packing nut. For example, the nut lockmay include an extendable pin that can be extended into a holeof the packing nut, thereby rotationally locking a position of the packing nut.

The packing gland assemblyincludes a plurality of fasteners(e.g., a plurality of bolts) to connect (e.g., fasten) the packing gland housingto the fluid end block. In this way, the packing gland housingcan be removed from the fluid end blockto facilitate repair or replacement of the packing gland housing. Accordingly, failure of a packing bore can be resolved more efficiently through removal of the packing gland assembly, rather than replacement of the entire fluid end. Moreover, by using a removable packing gland assembly, the fluid end blockcan be fabricated using a smaller raw starting block compared to a raw starting block that would be used to fabricate a fluid end block with integrated packing glands, thereby conserving a significant amount of material.

In some implementations, the fluid end blockis composed of a first material, and the packing gland housingis composed of a second material different from the first material. For example, the first material may be a first steel composition and the second material may be a second steel composition. This may facilitate simplified and lower-cost manufacturing of the packing gland housing.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating a perspective view of an example packing gland housing. The packing gland housingdefines a bore. The boreextends from a front end(e.g., a first end) to a rear end(e.g., a second end) of the packing gland housing. The boremay define an inner circumferential surface and an outer circumferential surface of the packing gland housing(e.g., the packing gland housingmay be annularly shaped). The boremay define a packing bore of the packing gland housing(e.g., where packing is filled) and/or define at least a portion of the plunger bore.

As shown, the packing gland housingincludes a plurality of aperturesconfigured to receive respective fasteners. The aperturesmay be located in the packing gland housingaround the bore. In some implementations, a portis defined through the packing gland housingfor introducing lube oil or grease into the bore.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating a cross-sectional view of the packing gland housingoftaken along line B-B. As shown, the packing gland housinghas a flangeand a mating neckextending from the flange. The flangeand the mating neckmay be an integral unit.

The flangemay have an overall annular shape, or another shape such as a hexagonal shape or octagonal shape. The flangehas a front face(e.g., a front annular face) that defines the front endof the packing gland housing, and a rear face(e.g., a rear annular face). The front faceand the rear faceof the flangedefine a thickness of the flange. The aperturesmay be defined in the flangeextending from the front faceto the rear faceof the flange. The aperturesmay be threaded to facilitate engagement with threads on the fasteners. In some examples, an aperturemay include a countersunk section and a threaded section. The front faceof the flangealso defining the front endof the packing gland housinggives the flangea significant thickness, which reduces movement of the packing gland housingand improves a seal strength between the packing gland housingand the fluid end block.

The mating neckmay extend from the flange(e.g., from the rear faceof the flange) to the rear endof the packing gland housing. For example, a faceof the mating neckmay define the rear endof the packing gland housing. The mating neckis configured for insertion into the fluid end block(e.g., such that the boreis aligned with a cylinder of the fluid end block). To achieve this, the mating neckdefines a stepped circumferential surface having one or more steps. Moreover, the mating neckdefines a circumferential grooveconfigured to receive a sealing ring, as described herein. The step(s)may be located between the circumferential grooveand the flange. In some implementations, the mating neckhas at least two steps. For example, a first stepmay project from the circumferential groove, and a second stepmay extend from the rear faceof the flange.

As further shown in, in some examples, the boremay include multiple sections having different diameters. For example, at a first section of the bore(nearest to the front endof the packing gland housing), the inner circumferential surface of the packing gland housingmay be threaded to engage with threads on the packing nut. A second section of the bore(a middle section) may define the packing bore (e.g., that is not threaded) that can be filled with packing. A third section of the bore(nearest to the rear endof the packing gland housing) may be narrower than the second section to define a ledge of the packing bore on which packing can be stacked.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating an enlarged cross-sectional view of the stepped circumferential surface of the mating neck. As shown, one or more of the stepsmay have a chamfered corner. For example, the stepthat extends from the rear faceof the flangemay have the chamfered corner. Additionally, or alternatively, a leading edge of the faceof the mating neckmay have a chamfered corner. The chamfered corners,may have a length-to-width ratio of X:1, where X>1 or X>2. For example, the chamfered corners,may have a length-to-width ratio of 3:1. The chamfered corners,facilitate guiding of the mating neckinto the fluid end block.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating a cross-sectional view of the fluid endoftaken along line A-A. The fluid endmay include a stepped portthat receives the mating neckof the packing gland housing. For example, the stepped portis matched to (e.g., is an inverse of) the stepped circumferential surface of the mating neck. Thus, with the packing gland housingconnected to the fluid end block, the mating neckof the packing gland housingis received into the stepped portof the fluid end block, the flangeof the packing gland housingabuts an exterior surface of the fluid end block, and the fastenersconnect the packing gland housingand the fluid end block.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

is a diagram illustrating an enlarged cross-sectional view of an interface between the fluid end blockand the packing gland housing. As shown, the faceof the mating neckdirectly abuts against the fluid end block(e.g., without an intervening pressure ring or gasket), thereby providing a flush interface between the mating neckand the fluid end blockthat promotes fluid tightness. To facilitate the flush interface between the fluid end blockand the faceof the mating neck, one or more gapsmay be defined between the stepsof the mating neckand the stepped portof the fluid end block. For example, a profile of the stepped portof the fluid end blockand a profile of the mating neckmay be configured to define the gaps. As an example, the chamfered corners,of the mating neck, as well as similar chamfered cornersof the stepped port(e.g., at a leading edge of the stepped portand/or at a corner of one or more steps of the stepped port), may result in the gaps. The gapsallow maneuverability between the fluid end blockand the packing gland housingto ensure a tight fit at the interface between the faceof the mating neckand the fluid end block.

As further shown, the packing gland assemblymay include a sealing ringdisposed in the circumferential groove. The sealing ringprovides an additional fluid-tight seal between the packing gland housingand the fluid end block. In some implementations, the sealing ringmay have a raised central portion and raised edge portions, thereby defining a channel between a first raised edge portion and the raised central portion and a channel between a second raised edge portion and the raised central portion.

As indicated above,is provided as an example. Other examples may differ from what is described with regard to.

The packing gland assemblydescribed herein may be used with any fluid pump that uses a plunger to pressurize fluid. For example, the packing gland assemblymay be used with a positive displacement pump, such as a reciprocating pump. In particular, the packing gland assemblymay be employed in a fluid pump used in an application relating to oil and gas extraction, such as hydraulic fracturing. The packing gland assemblycan be filled with a packing that surrounds the plunger to prevent leakage of fluid from around the plunger during pumping operations. In general, packing can wear down adjacent surfaces resulting in a “wash boarding” effect that can lead to leaks and seal failure. These surfaces may also experience wear due to high applied pressures within the fluid pump. When a packing gland is integrated with a fluid end block (e.g., as a single unit), the repair of worn surfaces is difficult, and oftentimes the entire fluid end block is replaced when repair is not possible.

The packing gland assemblydescribed herein is removable from the fluid end block. For example, the fastenersthat secure the packing gland housingto the fluid end blockcan be loosened to allow the packing gland housingto be removed for easier repair or replacement. Accordingly, the fluid end blockdoes not need to be scrapped merely because of worn surfaces of the packing gland housing.

Additionally, the packing gland assemblydescribed herein provides improved leak resistance. For example, the front faceof the flangealso defining the front endof the packing gland housinggives the flangea significant thickness, which reduces movement of the packing gland housingrelative to the fluid end blockand improves a seal strength between the packing gland housingand the fluid end block. Furthermore, the stepped circumferential surface of the mating neck, as well as the chamfered corners,define gapsbetween the stepsof the mating neckand the stepped portof the fluid end block, thereby allowing for maneuverability between the fluid end blockand the packing gland housing. This maneuverability ensures a tight fit where the faceof the mating neckdirectly abuts against the fluid end block, thereby improving fluid tightness and reducing leakage.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations. Furthermore, any of the implementations described herein may be combined unless the foregoing disclosure expressly provides a reason that one or more implementations cannot be combined. Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set.

As used herein, “a,” “an,” and a “set” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”). Further, spatially relative terms, such as “front,” “rear,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the apparatus, device, and/or element in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.