26 connect the plurality of pumping units 40 to the outlet manifold 100.

Each pumping unit 40 includes a pump 44 driven by a driver 42 (which may be referred to herein as a “prime mover”). Pump 44 may include any suitable fluid pumping device or assembly for pressurizing the fracturing fluid (with or without proppant and/or other additives entrained therein) to the pressures associated with a hydraulic fracturing operation. For instance, in some embodiments, the pump 44 may be configured to pressurize the fracturing fluid (again, with or without proppant and/or other additives entrained therein) to a pressure of about 9000 pounds per square inch (psi) or higher. Thus, pump 44 may be referred to herein as a “hydraulic fracturing pump” 44. In some embodiments, pump 44 may include a positive displacement pump, centrifugal pump, or other suitable pump types. Driver 42 may include any suitable motor or engine that is configured to drive or actuate the corresponding pump 44 during operations. For instance, in some embodiments, driver 42 may include a diesel engine, a turbine (such as a gas turbine, steam turbine, etc.), an electric motor, or some combination thereof. During operations, within each pumping unit 40, the driver 42 may actuate the pump 44 to draw fracturing fluid into the pump 44 via the corresponding inlet conduit 24 and to pressurize and output the fracturing fluid from the pump 44 via the corresponding outlet conduit 26.

The outlet manifold 100 is described in more detail below. However, generally speaking the pressurized fracturing fluid is received by the outlet manifold 100 via the outlet conduits 26. The outlet manifold 100 directs the pressurized fracturing fluid toward the wellhead 102 such that it may access the subterranean formation 103 as previously described. During the hydraulic fracturing operations, fracturing fluid may be emitted from the wellbore via the wellhead 102 and recycled back to the storage vessels 12 through one or more recycle conduits 16. In some embodiments, the fracturing fluid output from the wellhead 102 may be routed through one or more filtering or separation assemblies or devices (not shown) to remove additives, proppant, and/or other fluids or solids (such as, rock chips, formation fluids, etc.) that may be entrained within the fracturing fluid, prior to recycling the fracturing fluid to the storage vessels 12.

FIGS. 2 and 3 show the outlet manifold 100 of hydraulic fracturing system 10 of FIG. 1 according to some embodiments. The outlet manifold 100 is an elongate member having a central or longitudinal axis 105, a first or upstream end 100a, and a second or downstream end 100b opposite upstream end 100a. As used herein, the terms “upstream” and “downstream” are used to denote the general flow direction of fracturing fluid through the outlet manifold 100 during operations, according to some embodiments. This convention is used herein for clarity and convenience when describing the outlet manifold 100 and the components and assemblies thereof. An outlet 106 is positioned at the downstream end 100b that is fluidly connected to the wellhead 102 (FIG. 1).

In addition, outlet manifold 100 includes a plurality of tubular manifold sections 110 and a plurality of flow cross junctions 130 interleaved between the plurality of manifold sections 110 along the longitudinal axis 105. More particularly, each manifold section 110 extends axially between axially adjacent flow cross junctions 130.

Manifold sections 110 are elongate tubular members that are coaxially aligned along the longitudinal axis 105 (so that the manifold sections 110 may be referred to herein as “elongate manifold sections”). As is best shown in FIG. 3, each manifold section 110 includes a first or upstream end 110a, a second or downstream end 110b opposite upstream end 110a, and a throughbore 112 extending axially between the ends 110a, 110b. Some of the ends 110a, 110b are connected to an axially adjacent flow cross junction 130 along outlet manifold 100. For instance, at least one of the ends 110a, 110b of each manifold section 110 may be connected to a corresponding, axially adjacent flow cross junction 130 via flanges 114; however, other connection mechanisms are contemplated (such as a threaded connection, clamped connection, welded connection, etc.).

As shown in FIGS. 2-4, flow cross junctions 130 are axially spaced along longitudinal axis 105 and axially interleaved between the plurality of manifold sections 110 as previously described. During operations, the flow cross junctions 130 provide a plurality of inlets for pressurized fracturing fluid to enter the outlet manifold 100. As best shown in FIG. 4, each flow cross junction 130 includes a central axis 139 that is aligned with longitudinal axis 105 when flow cross junction 130 is connected within manifold 100. In addition, flow cross junction 130 includes a first or upstream end 130a, a second or downstream end 130b opposite upstream end 130a, and a radially outer surface 130c (or more simply “outer surface” 130c) extending axially between ends 130a, 130b relative to axis 139. A first or main flow bore 132 extends axially between the ends 130a, 130b relative to axis 139. The main flow bores 132 of flow cross junctions 130 are aligned and fluidly connected with the throughbores 112 of the axially adjacent manifold sections 110 along outlet manifold 100 such that the throughbores 112 and main flow bores 132 together define a manifold flow path 104 that extends through the outlet manifold 100 between the upstream end 100a and the downstream end 100b (and outlet 106) along axis 105 of manifold 100.

As shown in FIG. 3, in some embodiments, the manifold flow path 104 may be blocked by a blind or cap 108 at the upstream end 100a of outlet manifold 100 so that fracturing fluid may not flow out of outlet manifold 100 via the upstream end 100a. In the embodiment shown in FIG. 3, the upstream end 100a is defined by an upstream end 110a of one of the manifold sections 110. In some embodiments, the upstream end 100a of outlet manifold 100 may be defined by an upstream end 130a of one of the flow cross junctions 130 (such as the most upstream of the flow cross junctions 130). In some of these embodiments, the main flow bore 132 of the flow cross junction 130 defining or including the upstream end 100a of outlet manifold 100 may not extend fully to upstream end 100a (and the corresponding upstream end 130a) and cap 108 may be omitted. In addition, the downstream end 100b of outlet manifold 100 may define the outlet 106 of the manifold flow path 104. Specifically, in some embodiments, the downstream end 100b is defined by a downstream end 110b of one of the manifold sections 110. In some embodiments, the downstream end 100b may be defined by a downstream end 130b of one of the flow cross junctions 130 (such as the most downstream of the flow cross junctions 130).

In addition, as shown in FIG. 4, each flow cross junction 130 includes a plurality of inlet flow bores 134, 136 that extend from the radially outer surface 130c to the main flow bore 132. In particular, in some embodiments, a first inlet flow bore 134 and a second inlet flow bore 136 each extend radially from radially outer surface 130c to main flow bore 132 relative to axis 139 and axis 105. The inlet flow bores 134, 136 of the flow cross junctions 130 provide inlet flow paths into the manifold flow path 104 for the fracturing fluid output from the plurality of pumping units 40 during operations (FIG. 1).

In some embodiments, one or more of the flow cross junctions 130 may include a single inlet flow bore (such as inlet flow bore 134 or inlet flow bore 136) or may include more than two inlet flow bores. For instance, FIGS. 5 and 6 illustrate embodiments of the flow cross junction 130 that include more than two inlet flow bores. Specifically, FIG. 5 shows an embodiment of flow cross junction 130 that includes three inlet flow bores 131 in place of the inlet flow bores 134, 136. In addition, FIG. 6 shows an embodiment of flow cross junction 130 that includes four inlet flow bores 131 in place of the inlet flow bores 134, 136.

FIGS. 4 and 7-12 illustrate one of the flow cross junctions 130 of the manifold 100 shown in FIGS. 2 and 3 in greater detail according to some embodiments. The upstream end 130a and the downstream end 130b each include a plurality of mounting bores 133. The mounting bores 133 each extend axially into the flow cross junction 130 relative to axis 139 from the corresponding end 130a, 130b. The mounting bores 133 may also be circumferentially spaced (such as evenly circumferentially spaced) about axis 139 along each end 130a, 130b. The mounting bores 133 may be threaded (and thus may include internal threads) such that each mounting bore 133 may threadably receive a threaded stud 115 (FIG. 4), or other connection member, for connecting ends 130a, 130b to elongate manifold sections 110 via flanges 114 (FIGS. 2 and 3) as previously described.

In some embodiments, the first inlet flow bore 134 extends along a first axis 135 and the second inlet flow bore 136 extends along a second axis 137. The first axis 135 and the second axis 137 (and thus also the first inlet flow bore 134 and the second inlet flow bore 136, respectively) are radially opposite one another about the axis 139 (and thus also axis 105), and each axis 135, 137 extends radially with respect to axis 139. Thus, the axes 135, 137 are aligned along a common radially extending plane relative to axis 139. In some embodiments, axes 135, 137 may be axially offset from one another along axis 139 such the axes 135, 137 lie in different radially extending planes relative to axis 139. In addition, in some embodiments, one or both of the axes 135, 137 may not extend radially relative to axis 139. For instance, one or both of the axes 135, 137 (and thus also the inlet flow bores 134, 136, respectively) may extend at an angle (such as at an acute angle) relative to the axis 139. In addition, in some embodiments, one or both of the inlet flow bores 134, 136 may be curved.

In some embodiments, the outer surface 130c is a cylindrical surface that extends axially between the ends 130a, 130b relative to axis 139. However, other shapes are contemplated for outer surface 130c in other embodiments. For instance, in some embodiments, the outer surface 130c may include a polygonal cross-section (such as pentagonal, hexagonal, octagonal, etc.) along a plane passing radially through the central axis 139 so that the radially outer surface 130c may be a polygonal surface. The outer surface 130c may include one or more (such as one or a plurality of) flats or facets 138 formed therein. As will be described in more detail below, the facets 138 may form flat surface areas along the otherwise curved, cylindrical outer surface 130c that may be used to form or machine one or more inlet flow bores (such as, inlet flow bores 134, 136) and/or to provide engagement surfaces for lifting or supporting the flow cross junction 130 during operations. Because the outer surface 130c may be a cylindrical surface in some embodiments, the facets 138 may form or define radially inwardly extending recesses in the outer surface 130c.

The flow cross junction 130 may include a total axial length L₁₃₀that is measured axially (with respect to the axis 139) from the upstream end 130a to the downstream end 130b. In addition, the outer surface 130c may have an outer diameter (such as a maximum outer diameter) D₁₃₀that extends radially across the flow cross junction 130 with respect to the axis 139. In some embodiments, the outer diameter D₁₃₀may be greater than the axial length L₁₃₀. For instance, in some embodiments, the ratio of the axial length L₁₃₀to the outer diameter D₁₃₀(L₁₃₀/D₁₃₀) may be less than 1.

In some embodiments, one or more parameters or dimensions of the flow cross junction 130 may be selected to minimize a total size and weight of the flow cross junction 130 while still maintaining a sufficient amount of material to contain the high pressures associated with a hydraulic fracturing operation (or other fluid delivery operation as described herein). For instance, in some embodiments, parameters such as the outer diameter D₁₃₀and the number of mounting bores 133 may selected to comply with specifications set by trade associations such as, for instance, the American Petroleum Institute (API). In some embodiments, the outer diameter D₁₃₀and number of mounting bores 133 (among other parameters) may be selected to comply with API 6A specification for wellhead and tree equipment (see, for instance, Tables E.5 of API specification 6A including specifications for flanges to withstand 15,000 psi pressure).

As best shown in FIG. 4, in some embodiments, the flanges 114 of the elongate manifold members 110 may also be sized per the same specifications as the parameters of the flow cross junction 130 (e.g., such as API specification 6A as noted above). As a result, an outer diameter D₁₁₄of the flanges 114 may be the same (or substantially the same) as the outer diameter D₁₃₀of flow cross junction 130. Accordingly, the cylindrical radially outer surface 130c of the flow cross junction 130 may be flush (or co-planar) with a radially outer, cylindrical surface 117 of the flanges 114.

As best shown in FIG. 12, in some embodiments, the length L₁₃₀of the flow cross junction 130 may be selected to provide a minimum wall thickness (in the axial direction with respect to axis 139) about the inlet flow bores 134, 136 and to accommodate the mounting bores 133 for the threaded studs 115. For instance, in some embodiments, the mounting bores 133 may extend a minimum axial length L₁₃₃into the flow cross junction 130 from the ends 130a, 130b. The minimum axial length L₁₃₃may be selected to ensure sufficient threaded engagement between the studs 115 and mounting bores 133 to compress the flanges 114 of elongate manifold sections 110 into the ends 130a, 130b to thereby form fluid-tight connections therebetween (FIG. 4). In some embodiments, the minimum axial length L₁₃₃may be in a range from about 1.500 inches (in) to about 1.625 in. The minimum wall thickness about the inlet flow bores 134, 136 may be determined based on a stress analysis of the flow cross junction 130 at the expected fluid pressures (such as at about 9,000 psi or higher as previously described). Thus, the total axial length L₁₃₀of the flow cross junction 130 may be selected in some embodiments to provide the minimum axial length L₁₃₃for the mounting bores 133 and the minimum wall thickness about the inlet flow bores 134, 136.

As shown in FIGS. 4 and 7-13, a plurality of fluid coupling assemblies 150 are connected to each flow cross junction 130. For instance, a fluid coupling assembly 150 is connected to each of the inlet flow bores 134, 136 to provide a connection for a conduit connected to an output of pump of the hydraulic fracturing system 10 (FIG. 1). Each fluid coupling assembly 150 includes a coupling adapter 180 that is removably inserted within and extended outward from a corresponding one of the inlet flow bores 134, 136. Further details of embodiments of the inlet flow bores 134, 136 and coupling adapter 180 are provided below according to some embodiments.

FIG. 14 shows the first inlet flow bore 134 of flow cross junction 130 according to some embodiments. It should be appreciated that, in some embodiments, the second inlet flow bore 136 may be configured the same as the first inlet flow bore 134 shown in FIG. 14 such that the following description of embodiments of the first inlet flow bore 134 may be applied to describe embodiments of the second inlet flow bore 136. Thus, the features of first inlet flow bore 134 described herein and shown in the drawings (such as FIG. 14) may also be included within the second inlet flow bore 136 in some embodiments.

First inlet flow bore 134 has a first or outer opening 161 positioned at or along the outer surface 130c (particularly along the corresponding one of the facets 138) and a second or inner opening 163 positioned at the intersection between the first inlet flow bore 134 and the main flow bore 132 (FIG. 4). An internal shoulder 166 is formed within the first inlet flow bore 134. The internal shoulder 166 extends radially inward toward the central axis 155 and circumferentially about the central axis 135 within the first inlet flow bore 134. The internal shoulder 166 separates the first inlet flow bore 134 into a first or outer portion 134a extending axially from the outer opening 161 to the internal shoulder 166 and a second or inner portion 134b extending axially from the internal shoulder 166 to the inner opening 163.

The outer portion 134a of first inlet flow bore 134 includes a cylindrical surface 169 extending axially from outer opening 161 along axis 135 and internal threads 168 positioned axially between the cylindrical surface 169 and the internal shoulder 166. Internal threads 168 may include one or more grooves that extend radially into first inlet flow bore 134 and helically about the central axis 135.

A radially extending circumferential ledge or seat 165 is formed on the internal shoulder 166 within the outer portion 164a. A gasket 174 (or junk ring) may be positioned on the seat 165 that may sealingly engage both the internal shoulder 166 and the coupling adapter 180 (FIGS. 4 and 13) to prevent or at least restrict the leakage of fracturing fluid out of flow cross junction 130, between the coupling adapter 180 and the inlet flow bore 134 during operations.

Inner portion 134b includes a cylindrical surface 170 extending axially from internal shoulder 166 to the inner opening 163. In some embodiments, the cylindrical surface 170 and inner opening 163 may have an inner diameter that is the same as a minimum inner diameter of the internal shoulder 166. As a result, the cylindrical surface 170 may be flush and continuous with a radially inner surface of the internal shoulder 166. In some embodiments, the inner portion 134b may have a surface (such as a cylindrical surface) that has an inner diameter that is greater than or less than a minimum inner diameter of the internal shoulder 166. Thus, in some embodiments, the inner portion 134b may have one or more surfaces that have a variable (such as increasing or decreasing) inner diameter, such as a frustoconical surface (or chamfer), a curved surface, etc.

The facet 138 along outer surface 130c that is associated with the fluid coupling assembly 150 may be a planar surface that extends radially relative to central axis 135 and circumferentially about the outer opening 161 of first inlet flow bore 134. A plurality of mounting bores 159 extend axially into the flow cross junction 130 from the facet 138 and may be arranged about the outer opening 161. The mounting bores 159 may be threaded (at least partially) such that they may receive one or more threaded mounting members (such as, mounting members 212 described herein) during operations. In some embodiments, mounting bores 159 may be evenly circumferentially spaced about axis 155 along the corresponding facet 138.

FIG. 15 shows the coupling adapter 180 of one of the fluid coupling assemblies 150 according to some embodiments. According to some embodiments, coupling adapter 180 may be an elongate tubular member that includes a central axis 185, a first end 180a, and a second end 180b opposite the first end 180a. As shown in FIG. 13, the second end 180b may be inserted within the first inlet flow bore 134 (or the second inlet flow bore 136) such that the first end 180a is extended outward from the first inlet flow bore 134 when coupling adapter 180 is connected to the flow cross junction 130. Thus, first end 180a may be referred to herein as the outer end 180a and the second end 180b may be referred to as the inner end 180b of the coupling adapter 180. As shown in FIG. 15, coupling adapter 180 also includes a throughbore 182 and a radially outer surface 180c, each extending generally axially between ends 180a, 180b relative to axis 139.

Throughbore 182 extends axially through the coupling adapter 180 along central axis 185 from the outer end 180a to the inner end 180b. Thus, the throughbore 182 has a first or outer opening 181 positioned at the outer end 180a and a second or inner opening 183 positioned at the inner end 180b. An internal shoulder 184 is defined within the throughbore 182. In some embodiments, the internal shoulder 184 may be positioned axially closer (and more proximate) to the outer end 180a and outer opening 181 than the inner end 180b and inner opening 183. The internal shoulder 184 extends radially inward toward the central axis 185 within throughbore 182.

In addition, throughbore 182 may include a tapered or frustoconical surface 186 (or “chamfer”) that extends from outer end 180a and outer opening 181 and a cylindrical surface 187 extending axially from frustoconical surface 186 to shoulder 184. The frustoconical surface 186 tapers radially inward toward central axis 185 when moving axially from outer end 180a and outer opening 181 toward cylindrical surface 187. Thus, the inner diameter of throughbore 182 may decrease when moving axially from outer end 180a and outer opening 181 toward cylindrical surface 187.

A circumferential or annular groove 189 is positioned along cylindrical surface 187. The annular groove 189 extends both radially into cylindrical surface 187 (and thus radially away from central axis 185) and circumferentially about the central axis 185. In some embodiments (such as the embodiment shown in FIG. 15), the annular groove 189 is positioned on the cylindrical surface 187 at the intersection with internal shoulder 184; however, in some embodiments the annular groove 189 may be axially spaced from the internal shoulder 184 along cylindrical surface 187. The annular groove 189 may be configured to receive an annular sealing member (e.g., an O-ring, seal ring, etc.) therein (such as at least partially therein).

As illustrated by FIG. 4, during operations, a coupling 27 connected to a corresponding one of the outlet conduits 26 shown in FIG. 1 may be inserted into the throughbore 182 from outer opening 181. During this process, the frustoconical surface 186 may guide and center the coupling 27 within the throughbore 182, and the coupling 27 may be compressed into the shoulder 184. An annular seal member 29 positioned on shoulder 184 may sealingly engage with an outer surface of the coupling to prevent or at least restrict leakage of fracturing fluid out of the throughbore 182. As will be described in more detail below, a connector 193 connected to the coupling 27 may engage with coupling adapter 180 to secure the coupling 27 to the coupling adapter 180 during operations.

As shown in FIGS. 13, 15, and 16, an inner end face 191 is defined and positioned on the inner end 180b. The inner end face 191 may be a planar surface that extends radially relative to central axis 185 and circumferentially about the inner opening 183 of throughbore 182.

As shown in FIG. 15, radially outer surface 180c includes a first connection device 188a and a second connection device 190a. The first connection device 188a and second connection device 190a may be any suitable connection feature (such as threads, clamps, etc.). In some embodiments (such as the embodiment shown in FIG. 15), the first connection device 188 includes a first set of external threads 188 and the second connection device 190a includes a second set of external threads 190.

The first set of external threads 188 may be more simply referred to herein as “first threads” 188 and the second set of external threads 190 may be more simply referred to herein as “second threads” 190. The first threads 188 and the second threads 190 may be separate and axially spaced from one another along radially outer surface 180c. In addition, the first threads 188 may be positioned axially closer (and more proximate) to outer end 180a than inner end 180b, and second threads 190 may be positioned more proximate to inner end 180b than outer end 180a. For instance, in some embodiments, the first threads 188 are positioned at (and extend axially from) the outer end 180a and the second threads 190 are positioned at (and extend axially from) the inner end 180b. The first threads 188 and the second threads 190 may include one or more grooves that extend radially into radially outer surface 180c and helically about the central axis 185.

An annular groove or recess 192 is axially positioned between the first threads 188 and the second threads 190. The recess 192 extends radially into the radially outer surface 180c toward central axis 185 and defines a radially extending annular external shoulder 194 that faces axially toward the outer end 180a. The annular external shoulder 194 may be more simply referred to herein as an “external shoulder” 194.

A first or outer cylindrical surface 195 extends axially between first threads 188 and annular recess 192, and a second or inner cylindrical surface 196 extends axially between external shoulder 194 and second threads 190. A plurality of engagement bores 197 extend radially into the outer cylindrical surface 195. In some embodiments, the engagement bores 197 are evenly circumferentially spaced about central axis 185 along outer cylindrical surface 195. As will be described in more detail below, engagement bores 197 may engage with a suitable tool (such as a spanner wrench) to facilitate threaded engagement or disengagement of the coupling adapter 180 from one of the inlet flow bores 134, 136 (FIG. 13) during operations.

As shown in FIG. 15, one or more annular seal grooves or recesses 198 are positioned along the inner cylindrical surface 196. The recesses 198 may be axially spaced from one another along inner cylindrical surface 196 and may each be configured to receive an annular seal member 199 (which may include an elastomer seal member such as an O-ring) therein. In some embodiments, each annular seal member 199 may be axially compressed between a pair of seal rings 199a within the corresponding recess 198. As will be described in more detail below, when coupling adapter 180 is inserted within one of the inlet flow bores 134, 136 (FIG. 13), the annular seal members 199 positioned in recesses 198 may sealingly engage the inlet flow bore 134, 136 to prevent or at least restrict the leakage of fracturing fluid from through-passage 164 and coupling adapter 180 during operations.

As illustrated by FIGS. 4, 5, and 13, as previously noted, the coupling adapter 180 may represent the component of the fluid coupling assembly 150 having the highest likelihood of failure during a hydraulic fracturing operation. Thus, the coupling adapters 180 of fluid couplings 150 may be selectively installed or uninstalled from the inlet flow bores 134, 136 during operations. As a result, in the event of a failure of a coupling adapter 180 (such as at the first threads 188), the failed coupling adapter 180 may be readily and quickly removed and replaced without disturbing a flanged connection of the manifold 100 (or other more substantial coupling assembly or mechanism). Accordingly, by separately providing a coupling adapter 180 that is removably inserted within one of the inlet flow bores 134, 136 of flow cross junction 130, personnel may perform a much simpler and safer operation of disconnecting, removing, and replacing the coupling adapter 180 without disconnecting other more bulky connection mechanisms (or flanged connections).

When installing the coupling adapter 180 into the inlet flow bores 134, 136 of flow cross junction 130, the inner end 180b of coupling adapter 180 is inserted through outer opening 161 such that second threads 190 are threadably engaged with the interior threads 168 within the inlet flow bores 134, 136. More particularly, FIGS. 13 and 16 illustrate the coupling adapter 180 installed within the first inlet flow bore 134 (it being understood that a coupling adapter 180 may be installed within the inlet flow bore 136 in the same manner). As may be appreciated from FIGS. 13 and 16, the inner end 180b of coupling adapter 180 is inserted into outer portion 134a of first inlet flow bore 134 until second treads 190 abut or engage with inner threads 168. Thereafter, the coupling adapter 180 is rotated about axis 185 so that second threads 190 threadably engage with interior threads 168 to force coupling adapter 180 axially into inlet flow bore 134 from outer opening 161 along the central axes 135, 185. Threaded engagement of threads 190, 168 continues until inner end face 191 on inner end 180b is engaged with and urged into gasket 174 such that gasket 174 is axially compressed relative to axes 135, 185 between the inner end face 191 (and inner end 180b) and internal shoulder 166, and such that coupling adapter 180 is axially compressed relative to axes 135, 185 against internal shoulder 166 via gasket 174 along arrows 171 in FIG. 13. As previously described, the compression of gasket 174 between inner end face 191 and shoulder 166 (specifically seat 165) may create a fluid-tight seal that prevents or restricts fracturing fluid from leaking out of inlet flow bore 134 or throughbore 182 radially between coupling adapter 180 and outer portion 134a of inlet flow bore 134. During insertion of coupling adapter 180 within outer portion 134a of inlet flow bore 134, a suitable tool such as a spanner wrench may be engaged with the engagement bores 197 on coupling adapter 180 to impart torque to the coupling adapter 180 about the aligned axes 135, 185.

As shown in FIG. 17, in some embodiments, the junk ring 174 may comprise a metallic gasket that is axially captured and compressed between the coupling adapter 180 (particularly inner end 180b) and shoulder 166. As shown in FIG. 17, the junk ring 174 when configured as a metallic gasket or seal may include a central axis 455, a first end 450a, a second end 450b opposite the first end 450a, a throughbore 454 extending between ends 450a, 450b, and a radially outer surface 450c also extending between ends 450a, 450b. The radially outer surface 450c may include a radially extending, annular projection 452 that is positioned axially between ends 450a, 450b along axis 455. In addition, radially outer surface 450c may include a first frustoconical surface 456 extending from the first end 450a to the projection 452 and a second frustoconical surface 458 extending from the projection to the second end 450b. The first frustoconical surface 456 may diverge radially away from the axis 455 when moving axially from the first end 450a toward the projection 452, and the second frustoconical surface 458 may diverge radially away from the axis 455 when moving axially from the second end 450b to the projection 452. When the metallic junk ring 174 is installed within the inlet flow bore 134 (or the inlet flow bore 136) and compressed between the shoulder 166 and inner end 180b of coupling adapter 180, the central axis 455 of junk ring 450 may be generally aligned with the axes 135 (or axis 137), 185.

When the metallic seal junk ring 174 is compressed between the coupling adapter 180 and the shoulder 166, the first frustoconical surface 456 may be engaged with a corresponding and complimentary frustoconical surface (or chamfer) 460 formed within the throughbore 182 of coupling adapter 180, and the second frustoconical surface 458 may be engaged with a corresponding and complimentary frustoconical surface (or chamfer) 462 formed on the shoulder 166. Thus, as may be appreciated in FIG. 17, as the coupling adapter 180 is threadably advanced into the inlet flow bore 134 (or the inlet flow bore 136), the engagement between the frustoconical surfaces 456, 458, 460, 462 may impart a radially inward pressure onto the junk ring 174, and the projection 452 may be axially compressed between the coupling adapter 180 and shoulder 166 (or between seats formed thereon). The radially inward pressure imparted to the junk ring 174 via the engagement of frustoconical surface 456, 458, 460, 462 may be directed normally through the engaged surfaces 452, 460 and normally through the engaged surfaces 454, 462. Thus, the engagement between the frustoconical surfaces 456, 458, 460, 462 and potentially the engagement between coupling adapter 180, shoulder 166 and projection 452 may form a fluid-tight seal between the seal ring 174 that prevents (or at least restricts) the leakage of fracturing fluid out of the through-passage 164 and along the outer surface 180c of coupling adapter 180.

Thus, by threadably engaging the coupling adapter 180 within the first inlet flow bore 134 (or the second inlet flow bore 136), the coupling adapter 180 is axially compressed into the inlet flow bore 134 and against the internal shoulder 166 along the aligned axes 135, 185 (such as along arrows 171 in FIG. 13). Without being limited to this or any other theory, compressing the coupling adapters 180 axially into the inlet flow bores 134, 136 may counter a pressure of the fracturing fluid that may tend to push the coupling adapters 180 out of the inlet flow bores 134, 136 during operations.

As may be appreciated from FIG. 4, the insertion of the coupling adapter 180 within the inlet flow bore 134 may position the outer end 180a, the first threads 188, the engagement bores 197, the annular recess 192, and external shoulder 194 of coupling adapter 180 outside of the inlet flow bore 134 at the outer openings 161. Thus, the first threads 188 are accessible to allow connection to an output of one of the outlet conduits 26 as previously described. For instance, as previously described, a connector 193 (such as a threaded connector, a hammer union, a flanged connector, a clamp, a hub, a swivel, a weld component, etc.) of the coupling 27 may be threadably engaged with the first threads 188 to allow coupling adapter 180 to be connected to the coupling 27 (and thus to one of the outlet conduits 26 (FIG. 1)).

In addition, as shown in FIG. 13, when coupling adapter 180 is inserted and engaged within outer portion 134a of inlet flow bore 134 (or the inlet flow bore 136), the inner cylindrical surface 196 of coupling adapter 180 is engaged with cylindrical surface 169 within outer portion 134a. As a result, the annular sealing members 199 positioned within recesses 198 of coupling adapter 180 may be sealingly engaged between the recesses 198 and cylindrical surface 169 to provide and additional seal to prevent or restrict fracturing fluid from leaking radially between the coupling adapter 180 and the outer portion 134a of inlet flow bore 134.

As shown in FIGS. 13 and 18, after coupling adapter 180 is inserted and engaged within outer portion 134a of inlet flow bore 134 (or inlet flow bore 136) as described above, a retainer ring 204 may be engaged with external shoulder 194 on radially outer surface 130c of flow cross junction 130 to prevent (or restrict) rotation of the coupling adapter 180 within inlet flow bore 134 about axes 135, 185. Specifically, as best shown in FIGS. 18-20, the retainer ring 204 includes a first side 204a, a second side 204b opposite first side 204a, and central opening 206 extending along a central axis 205 between the first side 204a and the second side 204b. In addition, retainer ring 204 includes an annular projection 208 that extends circumferentially about the central opening 206 about central axis 205. Further, retainer ring 204 includes a plurality of mounting apertures 209 that extend axially between sides 204a, 204b that are circumferentially spaced about axis 205. In some embodiments, the mounting apertures 209 are uniformly circumferentially spaced about axis 205. As best shown in FIG. 20, each mounting aperture 209 includes a shoulder 210 (such as an annular shoulder).

As shown in FIGS. 18 and 19, retainer ring 204 may be formed of a plurality of ring segments 203 that may be joined together. In some embodiments, the retainer ring 204 includes two ring segments 203, each extending about 180° about the axis 205 when ring segments 203 are joined together to form the retainer ring 204. However, other numbers and arrangements of ring segments 203 are contemplated. For instance, in some embodiments, retainer ring 204 is formed of more than two ring segments 203. In addition, in some embodiments, the ring segments 203 (whether there are two or more than two) may have different arc lengths about axis 205.

As shown in FIGS. 13, 18, and 20, during operations, the ring segments 203 of retainer ring 204 are joined together about the coupling adapter 180 such that the projection 208 is inserted within the recess 192 on radially outer surface 180c of coupling adapter 180. A plurality of mounting members 212 (such as threaded screws) may be inserted through the mounting apertures 209 and threadably engaged within the mounting bores 159 formed on facet 138 of radially outer surface 130c of flow cross junction 130. The mounting members 212 may engage with the shoulders 210 formed in mounting apertures 209 so that projection 208 is compressed axially into the external shoulder 194 on coupling adapter 180. When retainer ring 204 is connected to flow cross junction 130 so that projection 208 is compressed against external shoulder 194 of coupling adapter 180, the central axis 205 of retainer ring 204 may be aligned with the central axis 185 of coupling adapter 180 and/or the central axis 135 of inlet flow bore 134.

Without being limited to this or any other theory, engaging the retainer ring 204 with the external shoulder 194 of coupling adapter 180 may further secure the coupling adapter 180 within the inlet flow bore 134 or inlet flow bore 136 against the pressure of the fracturing fluid within the outlet manifold 100 during operations as previously described above. In addition, engaging the retainer ring 204 with the external shoulder 194 of coupling adapter 180 may also relieve pressure on the engaged threads 168, 190