WO2019059928A1

WO2019059928A1 - A liquid mixture nozzle, a flow system and a method for dispersing particles in a liquid mixture

Info

Publication number: WO2019059928A1
Application number: PCT/US2017/052966
Authority: WO
Inventors: Ashok VELLAIAH RETNASWAMY
Original assignee: Alfa Laval Corporate Ab
Priority date: 2017-09-22
Filing date: 2017-09-22
Publication date: 2019-03-28
Also published as: CN111093816B; CN111093816A

Abstract

A nozzle 30 including a body having a flow inlet and a flow outlet. The nozzle also includes a converging section 32 having a decreasing diameter positioned adjacent the flow inlet, an orifice 33 positioned at a narrow end of the converging section, an intermediate section 35 having a constant diameter positioned adjacent the orifice, and a diverging section 36 having an increasing radius positioned adjacent the intermediate section and the flow outlet. Flow of a liquid through the nozzle results in a flow rate increase of the liquid within the converging section, and a subsequent flow rate decrease of the liquid in the diverging section, thereby facilitating particle dispersion within the liquid.

Description

A LIQUID MIXTURE NOZZLE, A FLOW SYSTEM AND A METHOD FOR DISPERSING PARTICLES IN A LIQUID MIXTURE

Technical Field

This disclosure relates to a liquid mixture nozzle, a flow system and a method for dispersing particles in a liquid mixture. Background Art

Within the oil and gas industry, there are certain needs for mixing particles within a liquid, such as drilling mud. The purpose of the mixing is to achieve homogenization and dispersion of particles in the liquid. A number of technologies for obtaining mixing are used, including rotating shear units, conventional stirring techniques, and vibration based techniques. The mixing is performed in one or more stages and is typically effected in one or more shearing zones where liquid undergoes "shear", which happens when liquid travels with a different velocity relative to an adjacent area or liquid volume.

One example of a mixer type is shown in patent document US3833718 which describes a so called jet mixer. This mixer is used for providing high shear mixing of liquid such as in the preparation of slurry solutions for well treating. The mixing principle is based on forming a shear zone at the confluence of opposing streams of a mixture of liquid and particles. The mixer is based on separating the liquid into two streams and then directing the streams towards each other. The streams are directed into the mixing zone from a location substantially at right angles to each other to cause mixing.

The described mixer seems to provide adequate mixing. However, it is estimated that the mixing of conventional mixers may be further improved. Summary

It is an object to at least partly improve the above-identified prior art. A further object is to provide an improved liquid mixture nozzle suitable for mixing drilling mud. These and other objects are achieved through a liquid mixture nozzle, a flow system comprising such a nozzle, and a method for dispersing particles in a liquid mixture as defined in the independent claims. Embodiments are defined in the dependent claims.

In one aspect of the disclosure, there is provided a liquid mixture nozzle for flowing a liquid mixture therethrough. The liquid mixture nozzle comprises a body having a flow inlet and a flow outlet, the flow inlet being connectable to a first piece of piping, and the flow outlet being connectable to a second piece of piping; a converging section having a decreasing diameter positioned adjacent the flow inlet; an orifice positioned at a narrow end of the converging section; an intermediate section having a constant diameter positioned adjacent the orifice; and a diverging section having an increasing diameter positioned adjacent the intermediate section and the flow outlet.

In a second aspect of the disclosure, there is provided a flow system comprising s a flow inlet pipe, a flow outlet pipe, and a first liquid mixture nozzle as mentioned above. The liquid mixture nozzle is connected to the flow inlet pipe at an upstream end of the liquid mixture nozzle, and connected to the flow outlet pipe at a downstream end of the liquid mixture nozzle.

In a third aspect of the disclosure, there is provided a method for dispersing particles in a mixture of liquid and particles. The method comprises the steps of flowing the mixture through a converging flow section to increase the velocity of the mixture, flowing the mixture through an orifice located downstream of the converging section, flowing the mixture through an intermediate flow section having a constant diameter, the intermediate flow section positioned downstream of the orifice and upstream of the diverging flow section, and flowing the mixture through a diverging section located downstream of the orifice, thereby generating turbulence within the mixture to enhance dispersing of particles within the mixture of liquid and particles.

In embodiments of the disclosure, the orifice of the nozzle has a central region and a plurality of angularly-spaced outer regions extending radially from the central region, thereby forming a star-like shaped orifice. Alternatively, the orifice may have a circular, elliptical or substantially rectangular shape.

Furthermore, in embodiments of the disclosure, the ratio of the cross sectional areas of the intermediate section to a narrow end of the converging section, i.e. immediately preceding the orifice, is within a range of 2:1 to 6: 1 , preferably 3: 1 to 6:1 , most preferred 4: 1 to 5: 1. Thereby, the liquid mixture passing through the orifice immediately enters a volume that has a significantly larges cross-sectional area. As a result, the flow velocity of the liquid mixture is rapidly decreased, resulting in significant turbulence that has a positive effect on the dispersion of the particles in the liquid mixture.

In embodiments of the disclosure, an angle between an axial centerline of the liquid mixture nozzle and a sidewall of the converging section is within a range of about 30 degrees to about 50 degrees. Thereby, the converging section provides a very rapid decrease in cross-sectional area, resulting in a rapid increase in the flow velocity of the liquid mixture. This will in turn lead to significant turbulence that has a positive effect on the dispersion of the particles in the liquid mixture.

In embodiments of the disclosure, an angle between an axial centerline of the liquid mixture nozzle and a sidewall of the diverging section is within a range of about 5 degrees to about 10 degrees. Thereby, there will be a relatively slow decrease in flow velocity along the diverging section.

In embodiments of the disclosure, the ratio between: (1) the angle between the axial centerline of the liquid mixture nozzle and the sidewall of the converging section, and (2) the angle between the axial centerline of the liquid mixture nozzle and the sidewall of the diverging section, is about 3:1 to about 10: 1.

In embodiments of the disclosure, the nozzle is provided as one integral unit. The nozzle is then preferably made of plastic. Alternatively, portions of the nozzle may be made of metal. For instance, the portion comprising the orifice may be made of metal to increase wear resistance. Also, in embodiments of the disclosure, the orifice may be provided in an orifice component that replaceable. Thereby, the shape or size of the orifice may be changed without replacing the entire nozzle. Also, the orifice component can be made as a wear component that may be replaced when worn out.

In embodiments of the disclosure, the nozzle comprises a first pressure sensing interface configured to determine a first pressure of the liquid mixture prior to entering the liquid mixture nozzle, and a second pressure sensing interface configured to determine a second pressure of the liquid mixture after exiting the nozzle.

In embodiments of the disclosure, the flow system comprises a second liquid mixture nozzle similar to the first liquid mixture nozzle, and a flow divider. The flow divider is configured to divide the liquid mixture entering through the flow inlet pipe of the flow system into two streams having a first stream diverted through a first branch having the first liquid mixture nozzle and a second stream diverted through a second branch having the second liquid mixture nozzle.

In embodiments of the disclosure, the first branch and the second branch of the flow system merge into a collision zone downstream of the first liquid mixture nozzle and the second liquid mixture nozzle. Preferably, the first branch and the second branch are positioned at an angle a of 60 degrees to 120 degrees relative to one another.

In embodiments of the disclosure, the flow system comprises a pressure sensing device operatively connected to a first pressure sensing interface configured to determine a first pressure of the liquid mixture upstream of the liquid mixture nozzle(s), and to a second pressure sensing interface configured to determine a second pressure of the liquid mixture downstream of the liquid mixture nozzle(s).

In embodiments of the disclosure, a method for enhancing the dispersion of particles in a mixture of liquid and particles comprises the steps of dividing a mixture flow into a first liquid mixture stream and a second liquid mixture stream, subjecting each of said first liquid mixture stream and said second liquid mixture stream to the method steps recited above, and colliding, after said method steps recited above, said first liquid mixture stream with said second liquid mixture stream, to provide said enhanced dispersion.

In embodiments of the disclosure, the method comprises measuring a first pressure of the drilling mud prior to flowing the mixture through the converging flow section, measuring a second pressure of the mixture after flowing the mixture through the diverging section, and adjusting a flow rate of the mixture introduced to the converging flow section based on a difference between the second pressure and first pressure.

In embodiments of the disclosure, drilling mud is provided as said mixture in the above recited methods.

The nozzle and flow system according to the present disclosure may include a number of different features as described below, alone or in combination. The flow system that is used in the method may include the same features. Aspects and advantages of the embodiments described herein will appear from the following detailed description as well as from the drawings. It is contemplated that aspects described in one embodiment may be incorporated into other embodiments without further recitation.

Brief Description of the Drawings

Embodiments of the disclosure will now be described, by way of example, with reference to the accompanying schematic drawings, in which:

Fig. 1 is a side view of a nozzle according to one aspect of the disclosure, Fig. 2 is a cross-sectional side view of the nozzle of Fig. 1 ,

Fig. 3 is a front view of the nozzle of Fig. 1 ,

Fig. 4 is a rear view of the nozzle of Fig. 1 ,

Fig. 5 is a cross-sectional perspective view of the nozzle of Fig. 1 ,

Fig. 6 is a rear view of a flow system for dispersing particles in a liquid,

Fig. 7 is a cross-sectional top view of the flow system of Fig. 6, Fig. 8 is a schematic cross-sectional top view of a flow system for dispersing particles, according to another embodiment of the disclosure, and

Fig. 9 is a schematic diagram of a method of dispersing particles in a liquid. Detailed description

Figs. 1-5 are various schematic views of a nozzle 30, according to aspects of the disclosure. With reference to Figs. 1-5, the nozzle 30 includes a body defined by an elongated cylindrical surface 303. The nozzle 30 includes an inlet 301 into which a liquid stream flows, and an outlet 302 from which the liquid stream exits the first nozzle 30. An exemplary liquid mixture for flow through the nozzle 30 is drilling mud.

In geotechnical engineering, drilling mud is used to aid the drilling of boreholes into the Earth. The main functions of drilling mud include providing hydrostatic pressure to prevent formation fluids from entering into a well bore, keeping a drill bit cool and clean during drilling, carrying out drill cuttings, and suspending the drill cuttings while drilling is paused and when the drilling assembly is brought in and out of the hole. The drilling mud used for a particular job is selected to avoid formation damage and to limit corrosion. Water-based drilling mud most commonly consists of bentonite clay with additives such as barium sulfate (barite), calcium carbonate (chalk) or hematite.

In addition, various thickeners may be used to influence the viscosity of the drilling mud, e.g. xanthan gum, guar gum, glycol, carboxymethylcellulose, po!yanionic cellulose (PAC), or starch. In turn, de-fiocculants, such as anionic poiyelectrolytes (e.g., acrylates, polyphosphate, iignosu!fonates, or tannic acid) may be used to reduced viscosity, particularly when using day-based muds. Other common additives include lubricants, shale inhibitors, and fluid loss additives (to control loss of drilling fluids into permeable formations).

Returning to the nozzle 30, the inlet 301 and the outlet 302 is, respectively, configured for connection or coupling to a piping or other components. In order to facilitate said coupling with piping or other components, according to the disclosed embodiment, the first nozzle 30 also includes a circumferential flange 38 adjacent the outlet 302. Adjacent the flow inlet 301 , the nozzle 30 has a reduced diameter section 190 for insertion into piping to facilitate coupling therewith. Alternatively, the positions of the flange 38 and reduced diameter section may be reversed, a flange may be utilized in place of the reduced diameter section 190, or a reduced diameter section may be utilized in place of the flange 38. The nozzle 30 includes, in a liquid flow direction, a liquid converging section 32 at the inlet 301 , an orifice 33, an intermediate flow section 35, and a diverging section 36. The liquid converging section 32 converges towards the orifice 33, e.g., the liquid converging section 32 has a cross-sectional area that decreases in a direction towards the orifice 33. Stated otherwise, the diameter of the converging section 32 decreases in a downstream direction. The converging section 32 may have a linear convergence or a curved convergence, or a combination thereof. The converging section 32 converges downward to an orifice 33, through which liquid travels.

The intermediate flow section 35 is located between the orifice 33 and the liquid diverging section 36. The intermediate flow section 35 has a constant cross-sectional area, e.g., a constant diameter. The intermediate flow section 35 may have a circular, elliptical, star-like or other suitable cross-sectional shape in a plane orthogonal to a central longitudinal axis of the intermediate flow section 35.

The diverging section 36 is positioned adjacent to and downstream of the intermediate flow section 35. The diverging section 36 may have a linear divergence, a curved divergence, a combination thereof or another shape for the divergence. The diverging section 36 may also have a step wise divergence. In this context "diverging section" may be understood as a section with a cross-sectional area that increases in a direction of a flow of the liquid. A linear divergence or a slightly curved divergence may be utilized, since such a divergence gives an advantageous relationship between a liquid velocity and a pressure drop when a liquid passes through the nozzle 30.

In one example, a ratio of the cross sectional areas of the intermediate section 35 to a narrow end of the converging section 32 (e.g., the portion of the converging section 32 adjacent the orifice 33) is within a range of 2: 1 to 6:1. Additionally or alternatively, the angle between an axial centerline 95 of the nozzle 30 and a sidewall of the converging section 32 (e.g., the half angle) is within a range of about 30 degrees to about 50 degrees. Moreover, the angle θ₂ between the axial centerline 95 and a sidewall of the diverging section 36 (e.g., the half angle) is within a range of about 5 degrees to about 10 degrees. It is contemplated that the ratio between the half angle of the converging section to the half angle of the diverging section is about 3: 1 to about 10: 1. In one example, the axial centerline of each of the converging section 32, the orifice 33, the intermediate flow section 35, and the diverging section 36 is coaxial with the axial centerline 95. In one example, the length of the intermediate flow section 35 is equal to or greater than the outer diameter of the nozzle 30 or the outer diameter of a pipe coupled to the nozzle 30. For example, when using the nozzle 30 with a 6 inch diameter pipe, the intermediate flow section 35 of the nozzle 30 may be 6 inches or longer.

As may be seen in Figs 3 and 4, the orifice 33 may have a star-like shape with a central region 331 and a plurality of angularly spaced-apart, outer regions 332 around the periphery of the central region 331 , such as the orifice of the Lobestar Mixing Nozzle®. The outer regions 332 provide, when a liquid flows through the outer regions 332, a vortex flow pattern that provides a shearing effect and thus improved dispersing of the particles in a liquid stream flowing through the nozzle 30. It is contemplated that other shapes may be used for the orifice 33, which in combination with one or more other aspects of the nozzle 30, facilitate a shearing effect and/or vortex generation to induce particle dispersion. In other examples, the orifice 33 may be of circular, rectangular, elliptical, or other shape.

The orifice 33 may be formed in an orifice component 34 that is arranged in the nozzle 30. The orifice component 34 is fixed to the first nozzle 30 by a set of fasteners 39, and is removable from the nozzle 30. This allows the orifice component 34 to be replaced by another orifice component, for example, having an orifice 33 of different size or shape, or using the orifice component as a wear component to be replaced when worn. The orifice component 34 may be omitted in the sense that the orifice 33 may be made as an integral part of the first nozzle 30. In one example, the nozzle 30 is made as one integral unit that includes the converging section 32, the orifice 33, the intermediate flow section 35 and the diverging section 36. In one example, the nozzle 30 is made of plastic. Additionally or alternatively, the orifice component 34 may be made from metal. For example, an orifice component 34 having a star-like shape formed therein may be formed from metal.

When a liquid stream flows through nozzle 30 via the nozzle inlet 301 , the liquid stream experiences an increased flow velocity as the liquid stream passes through the converging section 32. The liquid stream is subjected to increased shear as the liquid stream passes through the orifice 33 and the intermediate flow section 35 at the increased velocity, thereby facilitating dispersion of particles within the liquid stream. As the liquid stream flows through the diverging section 32, the liquid stream experiences a sudden decrease in flow velocity that creates turbulence which increases the dispersion of particles in the liquid stream. Thus, both the converging section 32 and the diverging section 36 increase the dispersion of particles in the liquid stream.

Fig. 6 is a rear view of a flow system 1 for dispersing particles in a liquid. Fig. 7 is a cross-sectional top view of the flow system of Fig. 6. The flow system 1 utilizes a plurality of nozzles, described above, to facilitate mixing of particles in a liquid mixture, such as drilling mud.

The flow system 1 has the principal form of a triangular piping component, with an inlet 2 at a center of the base of the triangle, and with an outlet 3 at the top of the triangle. Liquid F, such as drilling mud, includes particles P when the liquid enters the inlet 2. Once inside the flow system 1 , the particles P are dispersed in the liquid F, as will be described in detail below, before the liquid F leaves the flow system 1 via the outlet 3. The particles P may to some extent be dispersed in the liquid F when the liquid F enters the flow system 1 , but as a result of flowing through the nozzles 30 within the flow system 30, the particles within the liquid F become more evenly dispersed, thereby improving the rheology of the liquid F.

In detail, the flow system 1 comprises a flow divider 10 in form of a T-section pipe where the inlet 2 is the base of the flow divider 10. From the inlet 2 the flow divider 10 separates the liquid F into a first liquid stream F1 and a second liquid stream F2. The flow system 1 has a first liquid branch 1 1 that is connected to the flow divider 10 for receiving the first liquid stream F1. A second liquid branch 12 is connected to the flow divider 10, on a side that is opposite the side where the first liquid branch 11 is connected. The second liquid branch 12 receives the second liquid stream F2.

The first liquid branch 1 1 comprises a straight section 121 that is connected to the flow divider 10, a 90° pipe elbow 122 that is connected to the straight section 121 , an angled elbow 123 that is connected to the pipe elbow 122, and a second straight section 124 that is connected to the angled elbow 123. The angled elbow 123 is angled by half the angle a.

The second liquid branch 12 comprises a straight section 131 that is connected to the flow divider 10, at an opposite side of the flow divider 10 from where the straight section 121 of the first liquid branch 11 is connected. The second liquid branch 12 is similar to the first liquid branch 11 and has a 90° pipe elbow 132 that is connected to the straight section 131 , an angled elbow 133 that is connected to the pipe elbow 132, and a second straight section 134 that is connected to the angled elbow 133. The angled elbow 133 is angled by half the angle a.

The second straight sections 124, 134 of the first liquid branch 11 and the second liquid branch 12 are connected to a branch joining section 14 that receives the first and second liquid streams F1 , F2 from the first and second liquid branches 11 , 12. The branch joining section 14 has the shape of a y-section pipe. The branch joining section 14 comprises the outlet 3 and the branch joining section 14 has an internal collision zone 141 where the first liquid stream F1 and the second liquid stream F2 meet and collide. When the liquid streams F1 , F2 collide they undergo shear since the streams F1 , F2 travel with a different velocity relative each other when they meet in the collision zone 141. Generally the velocities of the liquid streams F1 , F2 are the same in terms of flow rate, but they have different directions which affects the shear. The collision zone 141 may also be referred to as a shearing zone.

The parts of the two liquid branches 11 , 12 are typically made of metal, such as steel, and may be joined to each other by welding. However, the second straight sections 124, 134 of the two liquid branches 1 1 , 12 are typically joined to their respective adjacent parts by two conventional clamps. For example, a first clamp 113 joins a first end of the second straight section 124 of the first liquid branch 1 1 to the angled elbow 123. A second clamp 114 joins the other end of the second straight section 124 of the first liquid branch 11 to the branch joining section 14. Two similar clamps join the second straight section 134 of the second liquid branch 12 in a similar manner to its adjacent angled elbow 133 and to the branch joining section 14. The clamps may have the form of any conventional clamps that are suitable for joining pipe components, and the sections 123, 124, 14, 134, 133 that are joined by the clamps are fitted with conventional flanges that are compatible with the clamp. By virtue of the clamps, it is possible for an operator to remove the second straight sections 124, 134 of the first and second liquid branches 11 , 12.

The first liquid branch 11 and the second liquid branch 12 are arranged at an angle a of 60° - 120° relative to one another to direct the first liquid stream F1 and the second liquid stream F2 towards each other at the corresponding angle a of 60° - 120°. As a result the first liquid stream F1 and the second liquid stream F2 meet in the collision zone 141 by the same angle a of 60° - 120°. The collision angle a between the liquid streams F1 , F2 is accomplished by angling each of the angled elbows 123, 133 by half the angle a.

It is also contemplated that the flow divider has a Y-section pipe, where the first liquid branch and the second liquid branch are not at right angles to the inlet pipe 2. If so, the angles of pipe elbows, corresponding to elbows 122, 123, 132, 133, are adapted such that the first liquid branch and the second liquid branch are arranged at an angle relative to one another to direct the first liquid stream F1 and the second liquid stream F2 towards each other at an angle a of 60° - 120°.

A first nozzle 30 is arranged in the first liquid branch 1 1 and a second nozzle 40 is arranged in the second liquid branch 12. The second nozzle 40 may incorporate the same features as the first nozzle 30, such that they are similar, or even identical. Thus, every feature that is described for the first nozzle 30 may also be implemented for the second nozzle 40. Each of the nozzles 30, 40 is removable from the liquid branch 11 , 12 in which the nozzles 30, 40 are located. Removal of the nozzles 30, 40 is accomplished by releasing respective clamps from the second straight sections 124, 134. The nozzles 30, 40 are located in the second straight sections 124, 134 and by taking a nozzle 30, 40 out from a respective removed straight section, the nozzles 30, 40 may be removed or replaced.

The flow system 1 has at the inlet 2 a first pressure sensing interface 71 and has at the outlet 3 a second pressure sensing interface 72. The pressure sensing interfaces 71 , 72 may be openings to which pressure sensing device 77 is connected. The pressure sensing device 77 is a conventional differential pressure gauge and has a first pressure inlet port 73 and a second pressure inlet port 74 that are attached to the pressure sensing interfaces 71 , 72, for example via two pressure conducting lines 75, 76. The differential pressure gauge performs the operation of pressure subtraction through mechanical means, which obviates the need for an operator or control system to determine the difference between the pressures at the pressure sensing interfaces 71 , 72. Of course, any other suitable pressure sensing device may be used for determining the differential pressure.

The inclusion of a pressuring sensing device 77 facilitates the determination and monitoring of performance of the flow system 1 , i.e. the capability of the flow system 1 to effectively disperse particles P in the liquid F. Specifically, the differential pressure across the flow system 1 is indicative of the extent of shear (and thus particle dispersion) occurring in a liquid as the liquid travels through the flow system 1 , and more specifically, as the liquid travels through one or more nozzles 30. The differential pressure over the flow system 1 is the difference between the pressure at a position near the inlet 2 and a pressure at a position near the outlet 3. For example, if the pressure at the inlet 2 equals 100psi and if the pressure at the outlet 3 equals 60psi, then the differential pressure is 40psi (100psi - 60psi).

During operation of the flow system 1 , the differential pressure is monitored and the flow rate of the liquid F is adjusted so as to obtain a predetermined differential pressure that is known to provide proper dispersion of the particles P in the liquid F. Exactly what the predetermined differential pressure should be may depend on a number of factors, such as the size of the flow system 1 , the type of the liquid F and the type of the particles, and is preferably empirically determined by adjusting the flow rate until the particle dispersion is satisfactory. The differential pressure that then can be read is then set as the predetermined differential pressure for the flow system 1 and for the types of liquid F and particles P that were used. The pressure sensing device 77 may not necessarily be a differential pressure gauge. The pressure sensing device 77 may also have the form of two conventional pressure meters that are connected to a respective pressure sensing interface 71 , 72. These pressure meters then indicate, e.g. to an operator, the differential pressure over the flow system since the operator may easily determine the differential pressure based on the readings form the pressure meters. It is also possible to indicate the differential pressure to a control system, for example by applying conventional electronic communication techniques. The control system can then adjust, in dependence of the measured pressure readings, i.e. in dependence of the differential pressure Δρ, a flow of the liquid F with the particles P that are introduced in the inlet 2 of the flow system 1.

Fig. 8 is a schematic cross-sectional top view of a flow system 900 for dispersing particles, according to another embodiment of the disclosure. The flow system 900 is similar to the flow system 1 , but includes only a single nozzle 30 and is arranged in a linear configuration with respect to incoming and outgoing liquid flow. Due to the linear configuration of the flow system 900, the flow system 900 occupies less space than flow system 1. Thus, the flow system 900 may be positioned in more space-constrained locations than flow system 1. Moreover, because only a single nozzle 30 is utilized in the flow system 900, compared to two nozzles 30 in the flow system 1 , manufacturing costs for flow system 900 are less than the manufacturing costs of flow system 1.

The flow system 900 is coupled to a flow inlet pipe 901 and a flow outlet pipe 902 by clamps 1 14, and is arranged in a linear configuration with respect to the flow inlet pipe 901 and the flow outlet pipe 902. In one example, it is contemplated that any bends or turns in the flow inlet pipe 901 and the flow outlet pipe 902 are positioned a distance from the nozzle 30 that is four times, and preferably at least six times, the outer diameter of nozzle 30. However, other distances are also contemplated. The use of linear pipe adjacent the nozzle reduces erosion or wear on tees and elbows in the vicinity of the nozzle 30, particularly for components downstream of the nozzle 30. In addition, such lengths of linear pipe also allows turbulence from the nozzle 30 to subside to mitigate damage to pipelines due to excessive vibrations and pressure fluctuations.

The nozzle 30 of the flow system 900 includes an inlet 301 into which the liquid stream F enters the nozzle 30, and a flow outlet 302 from which the liquid stream F leaves the first nozzle 30. A liquid converging section 32 is positioned downstream of the flow inlet 301 to converge liquid towards the orifice 33. An intermediate flow section 35 is located downstream of the orifice 33, between the orifice 33 and a liquid diverging section 36. The intermediate flow section 35 has a constant diameter. The liquid converging section 32 has a decreasing diameter in a direction towards the orifice 33, and the diverging section 36 has an increasing diameter in a direction towards the flow outlet 302. It is contemplated that the diameters of the orifice 33, the intermediate flow section 35, the converging section 32, and the diverging section 36 may be selected to permit a desired flow rate of liquid therethrough while maintaining a desired pressure drop between the flow inlet 301 and the flow outlet 302. To facilitate determination of the pressure drop, the flow system 900 may include a pressure sensing device 77, a first pressure inlet port 73, a second pressure inlet port 74, and two pressure conducting lines 75, 76, as similarly described above.

During operation, as the liquid stream F travels through the converging section 32, the velocity of the liquid stream F is increased. The liquid stream F then travels through the orifice 33 and the intermediate flow section 35 at the increased velocity. Subsequently, the liquid stream F travels through the diverging section 36, resulting in a decreased flow rate. The increase in flow rate of the liquid stream F through the orifice 33 and the subsequent decrease in flow rate of the liquid stream F results in a vortex motion of the liquid stream F, as well as turbulence within the liquid stream F. The vortex motion and the turbulence results in mixing of the liquid stream F with the particles therein, thereby resulting in a more homogeneous mixture of particles within the liquid stream F. It is contemplated that a measured pressure drop, as described above, is indicative of velocity changes in the liquid, thereby indicating the extent of mixing in the liquid stream F.

It is contemplated that the flow system 900 may be retrofitted to existing systems by placing the flow system 900 inline in a desired piping assembly. For example, the nozzle 30 may be spliced into an existing pipeline, or mounted as is shown in Fig. 8, i.e. with a flange 38 and a reduced diameter section 190. In another example, the nozzle 30 may be inserted into a section of piping, and held in place by a fastener, adhesive, or another manner. In some examples, it is contemplated that a single nozzle 30 is capable of mixing liquids and particles to nearly the same extent as the dual-nozzle configuration illustrated in Figure 7. In such an example, the orifice 33 of the flow system 900 is sized to have an area equal to the combined area of the orifices 33 within the nozzles 30, 40 of the flow system 1 , thus providing an equivalent throughput.

With reference to Fig. 9, a method of dispersing the particles P in the liquid F is illustrated. The method may be utilized with any of the above-described flow systems. The method includes operation 701 in which the liquid F with particles P is introduced into the inlet of an above-described flow system. Subsequently, in operation 702, a differential pressure Δρ is measured as described above. In response to the measured pressure differential, a flow of the liquid F with the particles P is adjusted in operation 703. The adjustment in operation 703 is performed until a predetermined differential pressure Δρ is obtained. In detail, the flow, or flow rate, of the liquid F with the particles P therein, may be adjusted in operation 703 by changing a speed of a pump that feeds the mixture of the liquid F and the particles P. A change in the pump speed changes the pressure at inlet of a flow system, which in turn changes the flow (flow rate) of the liquid F through the flow system 1. The flow may also be adjusted in operation 703 by throttling a valve that controls the flow of the liquid F having the particles P therein.

Benefits of the disclosed embodiments include improved mixing and dispersion of particles in a liquid mixture. The disclosed nozzle 30, flow system 1 , and flow system 900 are particularly well-suited towards drilling mud rheology improvement and solids dispersion into a liquid, e.g., solid/liquid mixing. Conventionally, in the drilling industry, the rheology of the drilling mud is the key parameter used to determine quality. At the same time, storage of drilling mud in large tanks for long periods of time is common, which usually results in the deterioration of the rheology because the particle ingredients in the drilling mud - such as barite and bentonite powders, calcium carbonite, or hematite - tend to settle in the tank. However, flow and/or circulation of the drilling mud and particles therein through the disclosed flow system improves the rheology of the mud without the need to add more powders, thereby reducing costs.

From the description above follows that, although various embodiments of the disclosure have been described and shown, the disclosure is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.

Claims

1. A liquid mixture nozzle (30) for flowing a liquid mixture therethrough, comprising:

a body having a flow inlet (301) and a flow outlet (302), the flow inlet being connectable to a first piece of piping, and the flow outlet being connectable to a second piece of piping;

a converging section (32) having a decreasing diameter positioned adjacent the flow inlet;

an orifice (33) positioned at a narrow end of the converging section;

an intermediate section (35) having a constant diameter positioned adjacent the orifice; and

a diverging section (36) having an increasing diameter positioned adjacent the intermediate section and the flow outlet.

2. The liquid mixture nozzle (30) of claim 1 , wherein the orifice (33) has a central region (331) and a plurality of angularly-spaced outer regions (332) extending radially from the central region.

3. The liquid mixture nozzle (30) of claim 1 or 2, wherein a ratio of cross sectional areas of the intermediate section (35) to a narrow end of the converging section (32) is within a range of 2: 1 to 6: 1.

4. The liquid mixture nozzle (30) of any one of claims 1-3, wherein an angle (θι) between an axial centerline (95) of the liquid mixture nozzle and a sidewall of the converging section (32) is within a range of about 30 degrees to about 50 degrees.

5. The liquid mixture nozzle (30) of any one of claims 1- 4, wherein an angle (θ₂) between an axial centerline (95) of the liquid mixture nozzle and a sidewall of the diverging section (36) is within a range of about 5 degrees to about 10 degrees.

6. The liquid mixture nozzle (30) of any one of claims 1-5, wherein the ratio between: (1) the angle (θι) between the axial centerline (95) of the liquid mixture nozzle and the sidewall of the converging section (32), and (2) the angle (θ₂) between the axial centerline (95) of the liquid mixture nozzle and the sidewall of the diverging section (36), is about 3: 1 to about 10: 1.

7. The liquid mixture nozzle (30) of any one of claims 1-6, wherein the orifice has an elliptical, circular, or rectangular shape.

8. The liquid mixture nozzle (30) of any one of claims 1-7, wherein the nozzle comprises plastic.

9. The liquid mixture nozzle (30) of any one of claims 1-8, wherein the orifice is formed in a metallic insert.

10. The liquid mixture nozzle (30) of any one of claims 1-9, further comprising a first pressure sensing interface (71) configured to determine a first pressure of the liquid mixture prior to entering the liquid mixture nozzle, and a second pressure sensing interface (72) configured to determine a second pressure of the liquid mixture after exiting the nozzle.

11. A flow system (1 ; 900), comprising:

a flow inlet pipe (2; 901);

a flow outlet pipe (3; 902); and

a first liquid mixture nozzle (30) as claimed in any one of the preceding claims, wherein the liquid mixture nozzle is connected to the flow inlet pipe at an upstream end of the liquid mixture nozzle, and connected to the flow outlet pipe at a downstream end of the liquid mixture nozzle.

12. The flow system (900) of claim 1 1 , wherein the flow inlet pipe (901) and the flow outlet pipe (902) are linear adjacent the nozzle (30) for a distance of at least four times an outer diameter of the nozzle, preferably at least 6 times the outer diameter of the nozzle.

13. The flow system (1) of claim 11 , further comprising a second liquid mixture nozzle (40), as claimed in any one of claims 1-10, and a flow divider (10), wherein the flow divider (10) is configured to divide the liquid mixture entering through the flow inlet pipe into two streams having a first stream diverted through a first branch (1 1) having the first liquid mixture nozzle (30) and a second stream diverted through a second branch (12) having the second liquid mixture nozzle (40).

14. The flow system of claim 13, wherein the first branch and the second branch merge into a collision zone (14) downstream of the first liquid mixture nozzle (30) and the second liquid mixture nozzle (40).

15. The flow system (1) of claim 14, wherein the first branch (30) and the second branch (40) are positioned at an angle a of 60 degrees to 120 degrees relative to one another.

16. The flow system (1 ; 900) of any one of claims 11-15, further comprising a pressure sensing device (77) operatively connected to a first pressure sensing interface (71) configured to determine a first pressure of the liquid mixture upstream of the liquid mixture nozzle(s) (30, 40), and to a second pressure sensing interface (72) configured to determine a second pressure of the liquid mixture downstream of the liquid mixture nozzle(s) (30, 40).

17. A method for dispersing particles in a mixture of liquid and particles, the method comprising:

flowing the mixture through a converging flow section to increase the velocity of the mixture;

flowing the mixture through an orifice located downstream of the converging section;

flowing the mixture through an intermediate flow section having a constant diameter, the intermediate flow section positioned downstream of the orifice and upstream of the diverging flow section; and

flowing the mixture through a diverging section located downstream of the orifice, thereby generating turbulence within the mixture to enhance dispersing of particles within the mixture of liquid and particles.

18. A method for enhancing the dispersion of particles in a mixture of liquid and particles, comprising:

dividing a mixture flow into a first liquid mixture stream and a second liquid mixture stream,

subjecting each of said first liquid mixture stream and said second liquid mixture stream to the method steps of claim 17, and

colliding, after said method steps of claim 17 or 18, said first liquid mixture stream with said second liquid mixture stream, to provide said enhanced dispersion.

19. The method of claim 17 or 18, further comprising:

measuring a first pressure of the mixture prior to flowing the mixture through the converging flow section;

measuring a second pressure of the drilling mud after flowing the mixture through the diverging section; and

adjusting a flow rate of the mixture introduced to the converging flow section based on a difference between the second pressure and first pressure.

20. The method of any one of claims 17-19, comprising:

providing drilling mud as said mixture of liquid and particles.