EP0445875B1 - Method and apparatus for mixing solids and fluids - Google Patents

Method and apparatus for mixing solids and fluids Download PDF

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Publication number
EP0445875B1
EP0445875B1 EP91200440A EP91200440A EP0445875B1 EP 0445875 B1 EP0445875 B1 EP 0445875B1 EP 91200440 A EP91200440 A EP 91200440A EP 91200440 A EP91200440 A EP 91200440A EP 0445875 B1 EP0445875 B1 EP 0445875B1
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European Patent Office
Prior art keywords
liquid
turbine
radius
pressure
accordance
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EP91200440A
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German (de)
English (en)
French (fr)
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EP0445875A1 (en
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James Althouse
Robert Hitt
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Sofitech NV
Compagnie des Services Dowell Schlumberger SA
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Sofitech NV
Compagnie des Services Dowell Schlumberger SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/70—Spray-mixers, e.g. for mixing intersecting sheets of material
    • B01F25/74—Spray-mixers, e.g. for mixing intersecting sheets of material with rotating parts, e.g. discs
    • B01F25/743—Spray-mixers, e.g. for mixing intersecting sheets of material with rotating parts, e.g. discs the material being fed on both sides of a part rotating about a vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis

Definitions

  • This invention relates to a method and apparatus for continuously mixing solid particles with a liquid composition, and especially for continuously mixing cement particles with mix water or mix fluid in the oil-, gas-, or geothermal industries, for the cementing of drilled wells.
  • Methods for the mixing of materials have long been divided into two general classes.
  • batch mix methods the required amounts of components of the mixture are placed in a vessel.
  • the components are stirred or circulated in the vessel in order to produce a specified volume of mixture.
  • continuous mix methods specified amounts of the required components of the mixture are metered into a mixing region. Here they are blended together, and the resulting mixture withdrawn at a rate equal to the volumetric rate of the incoming components.
  • the mixing region often consists of a simple stirred vessel but various forms of ejectors, jet mixers and the like, in which mixing is accomplished by eduction, are also well known.
  • Zingg and Stoskopf in U.S. Pat. No. 3,256,181 (1966) disclosed a method by which many of the advantages of continuous mixing methods are retained, and by which the disadvantage described above can be overcome.
  • the method depends on a pressure balance principle. Liquid is supplied under pressure to a mixing region and swirled so that an "eye" is opened to the atmosphere at the center of the mixing region. Rotation of an annular body of fluid establishes a pressure at the periphery of the body of fluid which balances the pressure of the supply fluid. Liquid cannot flow into the eye and flood out from the mixing region. Nor can atmospheric air cross the rotating annular body of liquid to reach the mixing region. When a specified amount of material (generally taken to be more dense than the liquid) is metered into the eye, it is propelled by rotation out into the pressurized liquid, mixed with the liquid, and the resulting mixture discharged under pressure from the mixing region.
  • a specified amount of material generally taken to be more dense than the liquid
  • the liquid supplied to the mixing chamber is pressurized by a centrifugal pump impeller.
  • These embodiments constitute one class of "constant volume” continuous mixers.
  • a change in the proportion of components it is sufficient to change the flowrate of the component being introduced into the eye of the mixing region.
  • a change in flowrate of material into the eye results in a net change of pressure in the mixing region.
  • This change in pressure will induce the opposite (volumetric) change in flow of liquid supplied by the centrifugal pump impeller in order to maintain pressure-balance in the mixing region. Consequently, control of the proportion of components of the mixture is simplified.
  • Zingg and Stoskopf (1966) did not recognize that ease of control could be the principal advantage of one of the embodiments of their method. Its potential value has only come to be recognized in the subsequent practice and further development of their method.
  • Zingg and Stoskopf's method The potentially poor performance of Zingg and Stoskopf's method was not recognized at the time it was disclosed. Their method was originally intended to be implemented for the production of a slurry of sand or sand-like particles and gel composition which is used in treatments intended to increase the productive efficiency of earth wells. At the time the method was disclosed, a typical volumetric ratio of particles to liquid was 1:10. Ratios as high as 1:4 were reported, but these represented exceptionally high solids loading and were intended to test the limits of then-current practice. A greater understanding of the processes involved in the treatment of earth wells, and improvements in gel composition and associated equipment, have led to the use of slurries with a volumetric ratio exceeding 1:1 in modern treatments. At these high volumetric ratios, implementation of Zingg and Stoskopf's method often produces an air-entrained slurry unsuitable for use.
  • Portland cement slurry is a second example of a liquid-particle system in which implementation of the method fails to produce an acceptable product.
  • Pumpable slurries of portland cement are introduced into earth wells in order to secure pipe or casing to the rock face of the well bore. These slurries often have volumetric ratios of particles to liquid exceeding 1:1.
  • Implementation of Zingg and Stoskopf's method produces a highly agglomerated, air entrained slurry of very poor quality.
  • Other examples of systems which require high volumetric ratios of particles to liquid will be obvious to those familiar with the art.
  • Zingg and Stoskopf's method is flawed because it incorporates no means to regulate the proportion of the inflowing materials at their point of contact. While the over-all ratio of particles to liquid can be controlled, their ratio when they are initially mixed cannot. Zingg and Stoskopf's method calls for the introduction of particles into the liquid at an uncontrolled volumetric ratio that is always much higher than that specified for the product mixture. The result is an air-entrained paste or mass of agglomerates which is not readily dispersed into a uniform slurry of acceptable quality. The reason why this result is a necessary consequence of implementation of their method, and the reason why it is a insurmountable flaw of that method can be best explained by consideration of the various forms of apparatus which have been applied to implement their method.
  • the blender apparatus disclosed by Zingg and Stoskopf in U.S. Pat. No. 3,326,536 (1967) has been replaced in current use by the apparatus first described by Althouse in U.S. Pat. No. 4,453,829 (1984). Both of these are continuous process mixers in which liquid and solid materials are fed at a relatively high rate through a relatively small mixing volume. The mixing volume is held almost constant by hydrodynamic gradients induced by the devices. That is, according to the method described by Zingg and Stoskopf (1966), one rotating element acts as a centrifugal-pump impeller and induces a flow of liquid and slurry through a casing.
  • a second rotating element is used to open an atmospheric eye at the top of the mixer where solids may be introduced directly.
  • These two rotating elements establish a hydraulic balance between them such that any change in the flow of solids through the slinger is dynamically compensated by a change in the flow of liquid induced by the impeller. Consequently, the mixing volume, although small with respect to the flowrate of materials through the mixer, remains almost constant. Extraneous means of volume- or liquid-flow-control are not used.
  • MacIntire (1986, 1987) attributes the capacity limitation to air entrained in the inflowing solid stream which is carried out into the casing by centrifugal forces. This entrained air can find its way to the impeller suction, resulting in a loss-of-prime condition. The impeller can no longer supply pressured fluid to the mixing region, and the process must be stopped. He discloses a means of allowing this air to vent back to the atmosphere before it reaches the impeller suction region.
  • the MacIntire device incorporates no means to assure a flow of air to the vent other than the radial pressure gradient established in its casing.
  • air can be carried to the impeller suction in spite of a provision for allowing it to vent.
  • the flow of solids into the mixer is typically controlled by feedback from an instrument or "densitometer” used to measure the density of the slurry at the outlet of the mixer.
  • density of an air-entrained slurry cannot be related to a set-point or desired density in any convenient manner. A control system of this type will always be more-or-less inaccurate.
  • the degree of respective energy demand is a strong function of particle size. Coarse sand at relatively low concentration does not form stable agglomerates. Very fine particles, like portland cement particles, readily form an intractable paste. Thus, when one mixes contrary to the rule, the quality of the mixed product will be a strong function of the physical properties, and ratio, of the components of the mixture.
  • Solids are continuously introduced into this slurry at the slinger where a local volume of heavier-than-desired slurry or paste is formed.
  • Liquid is continuously introduced at the impeller where a local volume of lighter-than-desired slurry is formed.
  • the agglomerated paste must be dispersed into previously mixed slurry and make-up liquid in order to form a blend of the correct density and consistency before its discharge from the casing.
  • the energy required to disperse it is several orders of magnitude greater than that required to disperse solid particles into fresh liquid at the desired ratio. Since the energy input into the mixer is relatively constant, product quality degrades rapidly as the solids-liquid ratio is increased.
  • a second important disadvantage of mixers based upon the slinger-impeller balance principle is that they flood with air at high flow capacities.
  • the size of the atmospheric eye in the slinger is determined by a balance of slinger hold-back pressure and impeller discharge pressure, as explained by Althouse (1984) in the patent cited above.
  • the impeller discharge pressure falls for two reasons. Firstly, a flow of fluid through a centrifugal impeller results in a net subtracive fluid velocity with respect to that tangential fluid velocity which establishes discharge pressure in the casing.
  • the fluid friction losses in the supply piping to the mixer grow. These losses result in a decrease in absolute pressure in the casing. It is the absolute casing pressure which is balanced by the slinger and "held back" to form an eye into which solids are added.
  • the atmospheric eye in the slinger becomes larger.
  • make-up fluid is supplied from a storage tank.
  • the hydrostatic head available at the liquid inlet to the impeller decreases.
  • the atmospheric eye is further enlarged by the effective loss of absolute casing pressure in the mixer.
  • Zingg and Stoskopf (1966, 1967) disclosed a constant level supply tank to supress this undesirable behavior, but their solution requires an additional piece of equipment and was never widely used.
  • the degradation of prodcut quality and risk of loosing prime are augmented by the sensitivity of mixers, based on the slinger-impeller balance principle, to the absolute pressure available at their inlet.
  • USP 3,606,270 describes a continuous power blender with a liquid annular inlet zone (44) and a particulate material introduction tube (28) centered into the said annulus (44). Both liquid and particulate material feedings are made in a specially arranged centrifugal pump showing an impeller (11) with blades (12) leaving a central "eye" recess (13). The liquid and the particles fall into the eye uncontrolled so that the eye cannot be stabilized.
  • USP 2,147,053 describes a cement mixer in which a turbine (27) is propelled by a water jet (22) and then provides "agitation" to the water/cement particles blend, while a succion phenomenon helps the feeding of cement.
  • the invention provides a method of mixing a pumpable liquid and a particulate material comprising:
  • the invention provides a method of mixing a pumpable liquid and a particulate material comprising :
  • the invention also provides an apparatus for mixing liquid and particulate solids comprising :
  • the method and apparatus disclosed herein do not suffer from any of the disadvantages inherent in the principles and practice of those taught by the prior art, but incorporate the objects of a simple, continuous, constant-volume mixing system.
  • the method is based upon the invention of a means by which solid particles may be introduced into a stream of fresh inflowing liquid before that liquid is recirculated into slurry of the desired density in a casing. Hydraulic balance is maintained based on a principle different from that applied in the prior art.
  • the method and apparatus also have other advantages over those used in current practice.
  • a primary object of the invention is to provide an improved mixing method and apparatus for continuously and rapidly intermixing a liquid and particulated solids, especially at high solids concentration and especially where the solids consist of fine particles.
  • a further object of the invention is to provide an improved mixer which can be operated over a wide dynamic flow-range of solids and liquids while minimizing the risk of unanticipated shut-downs and undesirable variations in mixture quality.
  • a further object is to provide an improved mixer which is low in self contained inventory, and wherein rapid changes may be effected in the volume of the materials being mixed while maintaining predetermined proportions of the components.
  • a further object is to provide an improved mixer which develops a positive flow pressure of the mixed slurry useful for moving the slurry to other equipment without requiring a pump or the like.
  • a further object is to provide an improved continuous mixer wherein the mechanism may continue to be operated, even though the delivery line from the mixer has been closed of otherwise shut off.
  • a further object is to provide an improved mixer which will continuously produce a liquid-solids mixture having a predetermined density.
  • a further object is to provide an improved mixer, especially for mixing cement particles and water in the oilfield industry, with no or little air in the cement slurry allowing accurate density measurement.
  • FIGURE 1 is front elevation view, mostly in section of the mixer apparatus of this invention.
  • FIGURE 2 is a progressive section view, looking down on the blender from above.
  • FIGURE 3 is a front elevation view, mostly in section of the turbine used in an alternate embodiment of this invention.
  • FIGURE 4 and FIGURE 5 represent a front elevation view, mostly in section, of two mixers according to the invention, preferred for oilfield applications.
  • an annular body of liquid is swirled in a casing by a turbine or an impeller element.
  • the rotation of the liquid serves to establish increasing radial velocity and pressure gradients in the liquid.
  • the absolute pressure is taken to be a minimum.
  • the absolute pressure is that developed by the rotation of the annular body of liquid between these radiii plus that at the inner radius.
  • Supply liquid is introduced into the swirling body of liquid across an annular section whose inner radius is greater than that of the inner radius of the rotating body of liquid and whose outer radius is less than that of the outer radius of the rotating body of liquid.
  • the pressure of the supply liquid is regulated such that it closely matches that of the rotating annular body of fluid across the section at which the supply liquid is introduced.
  • the inner radius of the rotating body of fluid defines an "eye".
  • the casing is open to the atmosphere over the circular section of the eye, and thus the pressure at the inner radius of the rotating annular body of liquid is fixed at atmospheric.
  • Supply liquid is introduced at a radius greater than that of the eye and at a pressure slightly more than atmospheric. Thus the pressure gradient in the rotating body of fluid is not disturbed, and the system remains in balance.
  • Supply liquid cannot flood the eye and flow out of the casing to atmosphere, nor can atmospheric air reach the source of supply liquid, nor can it be introduced into the mixture.
  • Solid particles and the like may be introduced into the eye where they contact the inflowing supply liquid arriving across the annular section. Vigorous mixing takes place in the rotating body of liquid where solids and inflowing supply liquid are brought into intimate contact.
  • the inflowing solid particles and liquid are continuously contacted together at the proper proportions or specified ratio of components for the mixture. Solids are not recirculated into already-mixed slurry so that the formation of agglomerates is precluded.
  • Liquid or slurry is drawn off from the casing at a pressure established by the rotation of the annular body of mixture in the turbine.
  • a pressure established by the rotation of the annular body of mixture in the turbine.
  • the mixer apparatus of this invention is generally indicated by the letter M.
  • the hopper serves as a container for solid particles, and is equipped with a solids-flow regulating means (valve 1) 12 which controls the flow of solids into a solids inlet cone 16 of the mixer.
  • valve 1 solids-flow regulating means
  • a drive shaft 18 is positioned inside the solids inlet cone 16, such that the bottom of the drive shaft extends through a solids inlet 17 of the mixer and into a casing 20.
  • the drive shaft 18 is coupled to a rotary drive means (not shown) which may or may not be supported by an element of the mixer as installation requirements dictate.
  • the mixing-pressurizing element of the mixer is a turbine 22 which is secured to the bottom of the drive shaft 18 by a bolt fastener 24 .
  • the turbine 22 is disposed within the casing 20 coaxially with the longitudinal axis of the casing.
  • the turbine has an insert 26 to which a plurality of blades 28 is attached. These blades extend in an inward radial direction along the top of the insert 26 to a radius approximately equal to or a little less than that of the radius 30 (FIG. 2) of the atmospheric eye of the mixer under "nominal conditions" that are defined below.
  • the atmospheric eye is a generally cylindrical volume defined by the interface 32 of atmospheric air with fluid composition in the mixer.
  • the interface is drawn in FIGURE 2 as a curly line to to indicate that it is never perfectly smooth or cylindrical in practice.
  • the blades are not extended fully into the eye to avoid interference with the flow of solids into the turbine.
  • the blades 28 are also extended in a inward radial direction along the bottom of the insert 26 to an inner radius which should be determined as follows.
  • the pressure at the periphery of the turbine insert 36 can never be allowed to be less than atmospheric or air will have entry to the suction region of the turbine. This adverse condition is precluded by seting the radius of the inner edge of the blades in the suction 34 less than that of the radius of the periphery of the insert 36 .
  • NPSHA net positive suction head available
  • the pressure developed in the annular body of fluid between the radius at 34 and the radius at 36 at the specified rotational speed of the turbine should be greater than the diference between atmospheric pressure and the minimum expected NPSHA.
  • annular turbine inlet 40 a continuation of the casing 20 and the insert 26 are configured to form an annular turbine inlet 40 between them.
  • the cross-sectional area of this inlet should be chosen such that the fluid is not accelerated in the suction in accordance with good hydraulic practice.
  • the turbine inlet 40 is connected directly and smoothly to the liquid suction inlet 42 also formed between the insert 26 and the inner casing wall.
  • Stator blades 44 which suppress liquid prerotation and make mixer performance more predictable, should be installed in the liquid suction by attachment to the casing inner wall.
  • the annular suction inlet is continued smoothly into circular section at the liquid inlet to the mixer 46 .
  • a manifold or fluid supply pipe 48 is provided to supply liquid from a liquid reservoir 49 .
  • the turbine blades 28 extend in an outward radial direction to the periphery of the turbine and are curved in conformity with good turbomachine design principles.
  • an upper shroud 50 is installed on the turbine between the solids inner edge of the blades 38 and the periphery of the turbine.
  • the shroud 50 serves to define a plurality of flow passages 52 between the blades and prevents inflowing solids from eroding the upper edges of the blades and the inner wall of the casing 20 opposite.
  • the height of these passages should be constant so that the outflowing mixture in the turbine is decelerated in the radial direction. Deceleration serves to minimize eductor effects which might induce air entrainment.
  • a plurality of pump-back vanes 54 in accordance with standard practice, is used to prevent backflow of materials in the gap between the shroud and the inner wall of the casing, which gap also serves as a means to exhaust air.
  • the turbine 22 discharges across its periphery into a receiver volume 55 defined by a continuation of the casing 20.
  • the receiver volume of the casing 55 is "semi-voluted.”
  • the cross-sectional area of this volume viewed normal to the tangential flow of mixture in the casing is increased starting from an edge 56 (FIG. 2) directly ahead of the discharge outlet 58 .
  • the law of increase is taken from good hydraulic practice and should be arithmetic with distance around the circumference of the mixer to the discharge outlet.
  • the total cross-sectional area is always made sufficiently large that the receiver volume of the casing 55 allows for recirculation of the mixture. This feature serves to damp out any irregularities in the flow of solids into the mixer, providing for more precise control of mixture quality.
  • the cross-sectional area should at no point be less than the outlet 58 cross-sectional area, which is determined by standard hydraulic practice.
  • the casing is voluted along the longitudinal axis of the mixer. This configuation is preferred over the standard method of radial voluting for two reasons. Firstly the the velocity, and consequently the pressure, opposite the turbine discharge is held relatively constant. Thus, the eye remains symmetric with the solids inlet, avoiding the risk a spray of fluid across a segment of that inlet. Secondly it provides a device of overall smaller diameter, which is more convenient and economical.
  • a certain portion of the discharged mixture may be recycled or recirculated from the discharge of the mixer 58 back to the liquid supply pipe of the mixer 48 by means of a recirculating pipe 60 .
  • the degree of recirculation is proportional to the size selected for this pipe and may be determined by rules and principles well known to those familiar with the art.
  • a valve (valve 2) 62 is provided so that the mixer can be operated in either the recirculating or direct mode according to the circumstances described herein.
  • FIGURES 1 and 2 illustrate a turbine of the radial type which is particularly suited for the specification of low specific speed. It would be selected when a relatively high discharge pressure with respect to capacity is required. At higher specific speeds where capacity is more important than discharge pressure, a Francis configuration would be specified. A vortex-type turbine is shown in FIGURE 3, on which the names and identifying numbers of the parts are retained. This configuration would be specified, for example, where extremely abrasive solids are processed, and close clearances in the solids or slurry flow-paths were especially undesirable.
  • the invention may be illustrated by describing a typical operation in which portand cement powder is mixed with water to obtain a cementatious slurry suitable for pumping into a well in order to provide a hydraulic seal between the casing and rock formations opposite that casing.
  • a drive means rotates the drive shaft 18 and turbine 22.
  • water is supplied to the inlet of the mixer 48.
  • the water flows into the turbine through the liquid inlet passage defined by the liquid inlet 46 of the mixer, the liquid suction inlet 42, and the annular turbine inlet 40.
  • the water is rotated by the turbine and develops pressure and velocity at is flows out into the casing receiver volume 55.
  • Air in the mixer is discharged through the gap between the turbine upper shroud 50 and the inner wall of the casing 20 directly opposite.
  • the mixer can be primed even when it is convenient to keep its outlet 58 blocked. Once the mixer has been primed in this fashion and is pumping, it will remain in a primed state even if the absolute pressure along the liquid inlet path is allowed to fall below atmospheric.
  • cement powder is metered into the turbine along the solids inlet path defined by the means of flow regulation 12, the solids inlet cone 16, the solids inlet 17, and the air-liquid interface 32.
  • the water and cement particles are brought into contact at this point. They then pass through the passages in the turbine 52 where they are mixed and pressurized as a slurry.
  • the mixer is operated in the recirculating mode with valve 62 open.
  • the outlet is opened and the slurry flows under pressure to a high-pressure pump which delivers it into a well.
  • cement powder continues to flow along the solids inlet path.
  • Water is drawn into the mixer through the liquid inlet path based on a volumetric balance which says that the rate of inflowing water equals the rate of outflowing slurry less the rate of inflowing cement powder.
  • the density of the slurry may be controlled by regulating the flow of cement powder into the mixer or by regulating the flow of slurry out of the mixer in combination or singly. Multiple control actions are not required.
  • the recirculation valve may be closed. This action is desirable when the mixer is required to operate around the maximum of its design capacity, and flow losses must be reduced. At lower capacity the valve should be left open in order to maintain more precise control of the density of the slurry.
  • the casing 20 of the mixer M contains a turbine 22 with blades 28.
  • the cement particles flow from the non-represented hopper 10 into the solid particles inlet 16, 17.
  • a stator 80 prevents the incoming fluid to spin, allowing a constant pressure to establish in the volume 82 immediately below the turbine 22.
  • the receiver volume 55 is most preferably limited outwardly by a somewhat cylindrical wall 81, and most preferably the slurry outlet 58 is placed behind the said wall as represented on Figures 4 and 5.
  • An horizontal disk 83 is provided above the turbine 22 so as to partially overlap with blades 28 as shown on Figure 4. While not essential for the operation of the mixer, this disk is most preferred since it prevents the outcoming of solids dust through the air escape vent 84.
  • the blades 28 may optionnally extend downwardly to form a scoop 85, the purpose of which is to keep the machine primed even at low presssure and expecially when the whole mixer M is built in an inclined configuration, by helping the incoming fluid to be forced upwards.
  • Such machines are especially useful for continuously mixing cement particles with mix water or mix fluid in the oilfield industry and related industry with a very accurate control and monitoring of the density of the produced slurry.
  • FIG 5 represents a further version of the machine represented on Figure 4, where the water or fluid inlet 46, 48 is located at the top of the casing 20. Water or fluid is flowing, either from an atmospheric tank 49 by gravity or through a feeding pump.
  • the water is introduced in the top cylindrical chamber 90 of the mixer, as defined by the upper part of the casing 20 and an intermediate horizontal wall 91.
  • Both the upper part of the casing 20 and the horizontal wall 91 feature a central hole as represented on Figure 5, aimed at providing space for the air vent 84 and the solid particles inlet 16.
  • the horizontal disk 91 ends inwardly with a certain overlap of the turbine blades 28 while the upper part of the casing 20 extends inwardly beyond the limit of the disk 91 so that the eye (air/slurry interface) can establish and get stabilized in a position which is intermediate between the two inwards limits of, respectively, the upper part of the casing 20 and the disk 91.
  • a fixed system of blades is positioned in the above mentioned central hole, so that the incoming water in chamber 90 is prevented from spinning.
  • the principal objects of the invention are effected because the proportions of the components of the mixture are never allowed to exceed the design or desired proportions in any part of the apparatus under a wide variety of typical operating conditions.
  • the turbine can be designed according to well-known design principles for turbo-machinery.
  • the blades may be swept back to define a best efficiency point or best-efficiency-point range for the machine. Erosion by abrasive solids is greatly reduced.
  • a slinger demands horsepower which serves neither to pump nor to mix, but is directly lost to heat.
  • the mixer disclosed here does not set an inefficient slinger against a potentially efficient impeller.
  • the normal drop-off of discharge pressure with increased capacity becomes a positive advantage instead of an insurmountable conceptual flaw.
  • the mixer requires about half the input horsepower of machines designed according to prior art.
  • a further advantage of the method is that a turbine configuration may be selected from a larger group of standard types than is possible in the design of machines based upon the teaching of prior art.
  • a turbine configuration may be chosen from a spectrum whose limits range from “radial flow” to “mixed flow” configurations.
  • a “vortex” or “recessed impeller” configuration may also be selected in accordance with this invention.
  • a further advantage is that the apparatus disclosed herein is smaller and cheaper than machines designed according to the prior art.
  • a further advantage is that the apparatus described here can be used in a variety of oilfield services.
  • the mixing of cement powder is used to illustrate its operation in detail because cement slurries are difficult to mix.
  • Mixers designed according to the teaching of the prior art were intended exclusively as sand blenders. They cannot mix cement slurry of acceptable quality under many circumstances. Cement particles readily form pastes and agglomerates which, because of the small size of the particles, are difficult to disperse into a consistent slurry.
  • Nor can mixers designed according to prior art mix acceptable gel or polymer solution. Water soluble polymers are also difficult to disperse in aqueous media. Many of these are effectively undispersible in a medium which already contains dissolved polymer.
  • the mixer disclosed here calls for the contact of solid particles with fresh make-up fluid at the proper solids-liquid ratio and maintains that ratio throughout their passage through the device. Consequently, it will mix high quality cement, gel, or sand slurry indifferently.
  • a further advantage is that the mixer disclosed here can process a large flow of solid particles whose density is less than that of the liquid also composing the mixture.
  • Machines designed according to the prior art are able to process small ratios of low-density solids due to recirculation of mixture in the chambers defined by the slinger blades, but they stop-up at typically higher rates. Since this mixer contacts inflowing particles with the full volumetric flow of fresh make-up liquid at the air-liquid interface, mixing of high solids-liquid ratios of low-density particles is not precluded.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
  • Processing Of Solid Wastes (AREA)
EP91200440A 1990-03-09 1991-03-01 Method and apparatus for mixing solids and fluids Expired - Lifetime EP0445875B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US49156190A 1990-03-09 1990-03-09
US491561 1990-03-09

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EP0445875A1 EP0445875A1 (en) 1991-09-11
EP0445875B1 true EP0445875B1 (en) 1995-12-13

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EP (1) EP0445875B1 (ja)
JP (1) JP2662104B2 (ja)
CN (1) CN1030692C (ja)
BR (1) BR9100951A (ja)
CA (1) CA2037797C (ja)
DE (1) DE69115308T2 (ja)
NO (1) NO180000C (ja)
RU (1) RU2079353C1 (ja)

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Publication number Priority date Publication date Assignee Title
FR2688709B1 (fr) * 1992-03-23 1994-09-02 Schlumberger Cie Dowell Melangeur d'additifs liquides en continu dans un fluide.
HU222031B1 (hu) * 1996-08-30 2003-03-28 Energiagazdálkodási Rt. Hidromechanikus keverőberendezés por vagy szemcsés halmazállapotú anyagból és folyadékból álló keverék előállítására
SE508868C2 (sv) * 1997-03-17 1998-11-09 Flaekt Ab Anordning för blandning av partikelformigt material och vätska
FR2767720B1 (fr) * 1997-08-27 1999-11-19 Denis Melangeur liquide(s)/solide(s) rotatif, en continu, a oeil ouvert
FR2767719B1 (fr) * 1998-02-04 2001-02-16 Denis Turbine pour melangeur liquide(s) / solide(s) rotatif, en continu, a oeil ouvert
US7048432B2 (en) * 2003-06-19 2006-05-23 Halliburton Energy Services, Inc. Method and apparatus for hydrating a gel for use in a subterranean formation
RU2271857C1 (ru) * 2004-12-27 2006-03-20 Закрытое Акционерное Общество "Вектор" Способ нормированного смесеобразования и устройство для его осуществления
RU2296613C2 (ru) * 2005-03-01 2007-04-10 Закрытое Акционерное Общество "Вектор" Способ регулирования кратности и/или производительности смесеобразования и устройство для его осуществления
WO2009087193A1 (en) * 2008-01-11 2009-07-16 Sulzer Pumpen Ag Method and apparatus for mixing of fluids
RU2483793C1 (ru) * 2012-01-10 2013-06-10 Валерий Тихонович Лиференко Смеситель
EP2895258A4 (en) * 2012-09-17 2016-05-18 Nov Condor Llc MIXING DEVICE AND METHOD
CN105984039B (zh) * 2015-02-04 2018-04-06 中国石油天然气股份有限公司 水泥浆搅拌装置
FR3032361B1 (fr) * 2015-02-10 2022-01-28 Exel Ind Melangeur pour aspirer et melanger un produit solide avec un liquide provenant d’une cuve de pulverisateur
CN110984129B (zh) * 2019-12-20 2021-09-28 中煤长江基础建设有限公司 一种河口滩涂地区的桩基设备及其操作方法
CN113083044B (zh) * 2020-01-08 2022-07-05 中国石油天然气股份有限公司 一种固体降阻剂连续混配装置及方法
CN114800860B (zh) * 2021-01-29 2023-05-12 三一汽车制造有限公司 搅拌装置的控制方法、搅拌装置和泵送设备

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US3606270A (en) * 1970-05-14 1971-09-20 Ludish Co Continuous power blender

Also Published As

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JPH04271821A (ja) 1992-09-28
DE69115308T2 (de) 1996-05-15
JP2662104B2 (ja) 1997-10-08
NO910936L (no) 1991-09-10
NO180000C (no) 1997-01-29
DE69115308D1 (de) 1996-01-25
CN1066804A (zh) 1992-12-09
EP0445875A1 (en) 1991-09-11
CN1030692C (zh) 1996-01-17
CA2037797A1 (en) 1991-09-10
CA2037797C (en) 2002-07-30
BR9100951A (pt) 1991-11-05
RU2079353C1 (ru) 1997-05-20
NO180000B (no) 1996-10-21
NO910936D0 (no) 1991-03-08

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