阅读说明：本技术 用于检测柱状状态的形成的水力旋流器 (Hydrocyclone for detecting the formation of a columnar state ) 是由 M·萨卡拉纳霍 T·索伊尼 J·库鲁宁 J·卡尔蒂宁 J·洛伊米 K·海斯卡宁 于 2019-01-11 设计创作，主要内容包括：一种用于将进料分离为溢流和底流的水力旋流器(100),包括进料入口(102)、溢流出口(104)、用于排出底流的沉砂口(130)、连接到进料入口(102)和溢流出口(104)的上部部段(110),位于上部部段(110)和沉砂口(130)之间的锥形部段(120),以及用于测量水力旋流器(100)内的电导率以检测水力旋流器(100)中的柱状状态的形成的多个电极(140)。所述多个电极(140)在所述锥形部段(120)中被周向地布置在距所述沉砂口(130)一轴向距离(d-(meas))处；其中,d-(meas)至少为所述沉砂口(130)和所述上部部段(110)之间的轴向距离的5％,并且d-(meas)最多为所述沉砂口(130)和所述上部部段(110)之间的轴向距离的50％。(A hydrocyclone (100) for separating a feed into an overflow and an underflow comprises a feed inlet (102), an overflow outlet (104), a grit chamber (130) for discharging the underflow, an upper section (110) connected to the feed inlet (102) and the overflow outlet (104), a tapering section (120) located between the upper section (110) and the grit chamber (130), and a plurality of electrodes (140) for measuring electrical conductivity within the hydrocyclone (100) to detect formation of a columnar state in the hydrocyclone (100). The plurality of electrodes (140) are arranged circumferentially in the conical section (120) at an axial distance (d) from the sand trap (130) meas ) At least one of (1) and (b); wherein d is meas At least 5% of the axial distance between the sand trap (130) and the upper section (110), and d meas At most between the sand trap (130) and the upper section (110)50% of the axial distance.)

1. A hydrocyclone for separating a feed into an overflow and an underflow, comprising:

a feed inlet;

an overflow outlet;

a sand setting port for discharging underflow;

an upper section connected to the feed inlet and the overflow outlet;

a conical section between the upper section and the sand trap; and

a plurality of electrodes for measuring conductivity within the hydrocyclone to detect formation of a columnar state in the hydrocyclone;

it is characterized in that the preparation method is characterized in that,

the plurality of electrodes are circumferentially arranged in the conical section at an axial distance (d) from the sand trap_meas) At least one of (1) and (b);

wherein d is_measAt leastIs 5% of the axial distance between the sand trap and the upper section, and d_measUp to 50% of the axial distance between the sand trap and the upper section.

2. The hydroclone of claim 1, wherein the plurality of electrodes comprises at least nine electrodes for Electrical Resistance Tomography (ERT) and/or Electrical Impedance Tomography (EIT) mapping.

3. The hydrocyclone according to claim 1 or 2, wherein the electrode thickness of the plurality of electrodes is at least 2.5 mm.

4. The hydrocyclone according to any of the preceding claims, wherein the plurality of electrodes are arranged in an annular gasket.

5. The hydroclone of claim 4 wherein the gasket is made of rubber or an insulating polymer.

6. The hydroclone of claim 4 or 5, wherein the tapered section is divided in an axial dimension into separate upper and lower portions and the gasket is sandwiched between the upper and lower portions.

7. The hydrocyclone according to any of claims 4 to 6, wherein the gasket has a thickness of at least 5 mm.

8. The hydroclone of any one of claims 4 to 7 wherein an outer circumference of the gasket comprises an extension for each of the plurality of electrodes.

9. Method for measuring electrical conductivity within a hydrocyclone to detect the formation of columnar conditions in the hydrocyclone, wherein the hydrocyclone comprises:

a feed inlet;

an overflow outlet;

a sand setting port for discharging underflow;

an upper section connected to the feed inlet and the overflow outlet;

a conical section between the upper section and the sand trap;

characterized in that the method comprises:

measuring electrical conductivity within the hydrocyclone by a plurality of electrodes arranged circumferentially in the conical section at an axial distance (d) from the grit chamber to detect formation of a columnar condition in the hydrocyclone_meas) At least one of (1) and (b); wherein d is_measAt least 5% of the axial distance between the sand trap and the upper section, and d_measUp to 50% of the axial distance between the sand trap and the upper section.

10. The method according to claim 9, wherein the weight of solid matter in the feed introduced into the hydrocyclone corresponds to 10-85% of the total weight of the feed.

11. The method according to claim 9 or 10, wherein the solid matter in the feed introduced into the hydrocyclone has a specific gravity of 1.5-7.0 tonnes per cubic meter.

Technical Field

The present disclosure relates to hydrocyclones (hydrocyclones). In particular, the present disclosure relates to an apparatus and method for detecting the formation of a roping condition in a hydrocyclone by measuring the electrical conductivity within the hydrocyclone.

Background

Hydrocyclones are classification devices for separating feed materials, such as mixtures of minerals. They are usually used in groups (cluster) to enable large quantities of feed material to be classified into several hydrocyclones. Hydrocyclones use centrifugal force to accelerate the settling rate of particles, thereby forming air nuclei (air core, air column) that are essential for the operation of the hydrocyclones. However, when the capacity of a single hydrocyclone is exceeded, the hydrocyclone can suffer from a condition known as columnar in which the air core collapses.

The detection of defects in the column prevents the operation of the hydrocyclones, such as reducing the operating time of a single hydrocyclone and increasing the number of hydrocyclones required to maintain any given capacity of the hydrocyclone battery.

Disclosure of Invention

Purpose(s) to

It is an object of the present disclosure to obviate or mitigate at least some of the above disadvantages.

In particular, it is an object of the present disclosure to provide a hydrocyclone and a method which can be used to more accurately detect the formation of columnar states in a hydrocyclone. It is another object of the present disclosure to provide a hydrocyclone that is configured to allow the formation of a columnar state to be detected before the occurrence of the columnar state, so that the operation of the hydrocyclone can be adjusted to prevent the occurrence of the columnar state.

SUMMARY

Hydrocyclones (hereinafter also referred to as "cyclones") are classification devices used for separating feed material, for example, on the basis of differences in the size and/or specific gravity of particles in the feed material. Alternatively or additionally, the separation may also be based on the shape of the particles. The feed rate is the rate at which feed material is introduced into the hydrocyclone. The feed material (hereinafter also referred to as "feed") may be, for example, slurry. The feed may comprise solid matter, such as mineral particles. The feed may also include a carrier fluid, such as water. For example, it has been found that the present disclosure can provide improved columnar detection when the weight of solid matter in the feed is 10-85% of the total weight of the feed, i.e., the feed has a solid matter content of 10-85%. As another example, it has been found that the present disclosure can provide improved column detection when the specific gravity of the solid substance is 1.5-7.0 tons/cubic meter.

The feed can be separated into at least an overflow, which corresponds to the fine product, and an underflow, which corresponds to the coarse product. The fine product may comprise at least on average smaller particles than the particles in the coarse product and/or particles having a smaller specific gravity. Cut-size (cut-size) is defined as the probability that a particle having the cut size will enter a fine product or a coarse product is the same. The axial dimension of the hydrocyclone is defined as the dimension corresponding to the height dimension of the cyclone. Accordingly, the axial dimension may also be denoted herein as the vertical dimension. By the beginning of the columnar state (onset) is here meant the moment at which the hydrocyclone is transferred to the columnar state. By formation of a columnar state (formation) is meant here any process associated with the transition of the hydrocyclone to a columnar state. These may be identified before and/or after the start of the columnar state, by definition. By determining the formation of a columnar state, it is here meant determining that a transition to a columnar state has occurred or is about to occur (is expected).

According to a first aspect, a hydrocyclone for separating a feed into an overflow and an underflow comprises a feed inlet (feed inlet). Which allows feed material to be introduced into the cyclone. The hydrocyclone also comprises an overflow outlet (overflow outlet) which allows extraction of overflow from the cyclone and a grit outlet (apex) for discharge of underflow from the cyclone. The hydrocyclone also comprises an upper section connected to the feed inlet and the overflow outlet and a conical section between the upper section and the sand trap. This configuration allows centrifugal separation of the feed in the cyclone. The hydrocyclones may be arranged for use as part of a hydrocyclone battery. This allows a large amount of feed material to be divided into several hydrocyclones for classification.

In order to measure the electrical conductivity inside the hydrocyclone to detect the formation of columnar states in the hydrocyclone, the hydrocyclone comprises a plurality of electrodes. However, although simply including a measuring electrode and measuring the conductivity within the hydrocyclone at the appropriate location may be used to detect the column after the column state has commenced, it has been found that the accuracy of detection can be significantly improved by selective positioning of the electrode. Thus, in the disclosed hydrocyclone, a plurality of electrodes are circumferentially arranged in a conical section at an axial distance (d) from the sand trap opening_meas) At least one of (1) and (b); wherein d is_measIs at least 5% of the axial distance between the sand setting opening and the upper section, and d_measAt most 50% of the axial distance between the sand trap and the upper section. In practice, the axial distance between the sand trap and the upper section may correspond to the height of the conical section. It has been found that the arrangement of the electrodes as described above results in a significant improvement of the measurement accuracy, in particular for column detection, which may further allow the start of the column state to be determined in advance, or a transition to be made to occurA columnar state. It is noted that increased accuracy may correspond to an increased probability for providing a correct determination of whether a columnar state actually occurs at any given time before or after the columnar state begins. Alternatively or additionally, the increased accuracy may correspond to being able to determine at an earlier time when the cyclone is in operation that a columnar state has occurred or is about to occur with a full or threshold confirmation.

It is emphasized that the column detection according to the present disclosure may be preemptive (pre-emptive), although the occurrence of column states may also be observed by other means for detecting column comprised in the hydrocyclone and/or even directly by visual inspection. This is in contrast to methods and apparatus that can only determine the occurrence of a columnar state if it has occurred or is too late to prevent it. In the context of the present disclosure, it should be noted that the columnar shape is not a phenomenon that is easily reversed (reversible), but has a large degree of hysteresis. For non-preemptive detection, it may be necessary to stop the hydrocyclone for a longer time after the columnar state is detected in order to restore the air core. While this disadvantage can be avoided by including one or more backup hydrocyclones in the hydrocyclone battery, the preemptive detection can both reduce the number of hydrocyclones required in the battery and increase the runtime of the battery. While one or more backup hydrocyclones can be used to maintain the overall capacity of the stack (even when one or more hydrocyclones are temporarily shut down after a column is detected in one or more hydrocyclones), interruption of normal operation may shorten the run time of the stack, for example, due to feed re-routing.

For preemptive columnar detection according to the present disclosure, an imminent transition to a columnar state may be determined before the columnar state begins. This may also mean that a threshold reaction time before the start of the columnar state determines that a transition to the columnar state is imminent, wherein the threshold reaction time is long enough to enable adjustment of the operation of the hydrocyclone, for example by reducing the feed rate of the cyclone, to prevent transition to the columnar state.

The hydrocyclone can include or be connectable to one or more controllers configured to perform measurements and/or determine the formation of a columnar state. The measurement and/or detection may be arranged to be performed automatically.

In one embodiment, the plurality of electrodes includes at least nine electrodes. It has been found that this minimum number of electrodes can be used to generate a two or more dimensional map suitable for cylindrical detection, allowing further improvement of the detection accuracy, especially for cylindrical detection. The plurality of electrodes may be arranged for Electrical Resistance Tomography (ERT) and/or Electrical Impedance Tomography (EIT) mapping.

In one embodiment, the thickness of the electrodes in the plurality of electrodes is at least 2.5 millimeters. It has been found that this can improve the detection accuracy, especially for column detection.

In an embodiment, the plurality of electrodes are arranged within the annular gasket. This allows various effects such as easier and more reliable mounting, improved electrode protection, and therefore, it is also possible to improve detection accuracy and reliability. In another embodiment, the gasket is made of rubber or an insulating polymer, allowing for electrical insulation and resilient coupling with the tapered section of the hydrocyclone to make liquid proof contact. In another embodiment, the tapered section is divided in the axial dimension into separate upper and lower portions with the shim sandwiched therebetween. This allows for accurate and easy positioning of the plurality of electrodes. In yet another embodiment, the thickness of the shim is at least 5 millimeters. This allows the gasket to accommodate an electrode having a thickness of about 3 mm, for example 3 mm 0 to 1 mm, while maintaining a reliable insulating layer on the electrode. In another embodiment, the outer circumference of the spacer includes an extension for each of the plurality of electrodes. This allows the gasket to be secured between the electrodes in the hydrocyclone, while extending the protection provided by the gasket to the electrodes. The extensions for each electrode may be independent, or two or more electrodes may share an extension.

According to a second aspect, a method for measuring conductivity within a hydrocyclone to detect is disclosedA method of forming columnar features in a hydrocyclone. The hydrocyclone comprises a feed inlet, an overflow outlet, a grit chamber for discharging the underflow, an upper section connected to the feed inlet and the overflow outlet, and a conical section between the upper section and the grit chamber. Any or all of the features described above in relation to the first aspect may be considered to also be in relation to the hydrocyclone of the second aspect. The method comprises measuring the electrical conductivity inside the hydrocyclone using a plurality of electrodes arranged circumferentially in the conical section at an axial distance (d) from the grit chamber_meas) Where d is_measAt least 5% of the axial distance between the sand trap and the upper section, and d_measUp to 50% of the axial distance between the sand trap and the upper section. This measurement is performed to detect the formation of a columnar state in the hydrocyclone. The detection of the formation of the columnar state may also be performed in a separate step, e.g. by a separate device. The measurement and/or detection may be determined by a controller that is part of the hydrocyclone. However, it is also possible that one or both of the steps are performed by a controller separate from the hydrocyclone, and the hydrocyclone may be arranged in connection or connectable to such a controller. The measurement and/or detection may be arranged to be performed automatically. As described above, this detection may be performed preemptively.

An alarm may be generated when the formation of a columnar state is detected before and/or after the columnar state begins. Alternatively or additionally, the operation of the hydrocyclone may be controlled to prevent or eliminate the columnar state, for example by reducing the feed rate into the hydrocyclone.

Feed is introduced into the hydrocyclone through one or more feed inlets. The feed may consist of solid matter and a carrier fluid. During operation of the hydrocyclone, the material corresponding to the feed is separated, for example, based on differences in the size and/or specific gravity of the particles in the feed. When the conductivity is measured in the hydrocyclone, the material corresponding to the feed from which the conductivity is measured may have been completely or partially separated.

In one embodiment, the weight of solid matter in the feed introduced into the hydrocyclone corresponds to 10-85% of the total weight of the feed. Accordingly, the weight of carrier fluid in the feed can correspond to 15-90% of the total weight of the feed.

In one embodiment, the solid matter in the feed introduced into the hydrocyclone has a specific gravity of 1.5-7.0 tonnes per cubic meter.

It should be understood that the above aspects and embodiments may be used in any combination with each other. Several aspects and embodiments may be combined to form another embodiment.

Drawings

The accompanying drawings, which are included to provide a further understanding of the specification and are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description help to explain the principles of the invention. In the drawings:

FIG. 1 schematically illustrates a side view of a hydrocyclone in accordance with an embodiment;

FIGS. 2a and 2b show a perspective view and a side view, respectively, of a lower section of a hydrocyclone according to an embodiment;

FIG. 2c illustrates a side view in cross-section of a lower section of a hydrocyclone in accordance with an embodiment;

FIG. 3 illustrates a side view of a clamp of a hydrocyclone in accordance with an embodiment; and

fig. 4a and 4b illustrate a gasket of a hydrocyclone according to an embodiment.

In the drawings, like reference numerals are used to designate identical or at least functionally equivalent components.

Detailed Description

The detailed description provided below in connection with the appended drawings is intended as a description of the embodiments and is not intended to represent the only forms in which the embodiments may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different embodiments.

A hydrocyclone (hereinafter also referred to as "cyclone") is a process apparatus suitable for classifying a large quantity of feed material, such as slurry. Depending on the size of the cyclone, the flow velocity may even exceed one cubic meter per second of feed, whereas typical values range from 25 cubic centimeters per second to 2 cubic meters per second. Examples of the construction and operation of hydrocyclones are disclosed in Mineral processing Technology, 8 th edition (chapter 9.4), e.g. by Wills (wils).

Fig. 1 schematically illustrates a hydrocyclone 100 according to an embodiment. Cyclone 100 is adapted to fractionate the feed by separating it into underflow and overflow, and it may also be adapted for specific purposes such as mineral processing. To introduce feed into the cyclone 100, the cyclone includes a feed inlet 102, which may be convoluted. The feed inlet 102 may be adapted to minimize flow turbulence of the feed, for example, by oblique flow direction and/or the absence of sharp corners.

To remove overflow from the cyclone 100, the cyclone 100 comprises an overflow outlet 104, which may comprise or be formed by a duct. The overflow outlet may include a vortex finder 106 extending into the cyclone 100. The vortex finder 106 is removable. The overflow outlet 104, and in particular the vortex finder 106, may be located at the central axis of the cyclone 100. The overflow outlet 104, and in particular the vortex finder 106, may extend into the cyclone 100 in the axial dimension beyond the bottom edge of the feed inlet 102.

To discharge underflow from cyclone 100, the cyclone includes a grit chamber 130 (also referred to as an underflow tube). The grit chamber 130 is generally facing downwardly so that the underflow is discharged downwardly from the cyclone 100. The grit chamber 130 may be located at the central axis of the cyclone 100. Typically, the hydrocyclone 100 includes only one grit chamber 130 and one overflow outlet 104, but configurations incorporating multiple grit chambers 130 are also possible. For such a configuration, a single feed inlet 102 and/or overflow outlet 104 may correspond to multiple sand settling ports 130.

The hydrocyclone 100 comprises an upper section 110 which may be cylindrical or substantially cylindrical. However, in some embodiments it may be at least slightly inclined so that its overall shape may be considered to be conical. The hydrocyclones 100 are produced for many different applications, and accordingly, their dimensions and measurements, such as the height (h) of the upper section 110_up) Can make it possible toWill be different. Although the diameter (D) of the upper section may also vary, in embodiments particularly suitable for mineral processing the diameter may be 50-1400 mm. Generally, a smaller diameter corresponds to a smaller cut size (cut size). An important parameter defining the shape of the upper section 110 is the shape factor (h)_up/D), for example, it may be from 0.6 to 2. The upper section 110 extends down to the level d of the bottom of the upper section 110_up. At this level, the upper section 110 may have an annular inner cross-section in a plane perpendicular to the axial dimension.

The hydrocyclone 100 also includes a conical section 120 located between the upper section 110 and the grit chamber 130. Height (h) of the conical section 120_cone) May vary. The conical section 120 is adapted to form a settling space for the feed introduced into the cyclone 100. In particular, the cyclone 100 is adapted to settle an underflow in the conical section 120 so that it can be discharged from the sand settling port 130. To this end, the tapered section 120 narrows towards the sand trap 130, and the narrowing may be continuous. The tapered section 120 may have one or more frustoconical sections. Each of these frustums may also narrow toward the sand trap 130. The tapered section 120 has an inclination angle (α) with respect to the axial dimension, which may be fixed or substantially fixed. However, in some embodiments, the angle of inclination may vary continuously or discontinuously along the axial dimension of the tapered section 120. In either case, the angle may be, for example, 10-30 degrees. Larger angles may be used for coarser partition sizes, while smaller angles may be used for finer partition sizes. When the inclination angle is changed, it may be arranged to always have a larger angle above a smaller angle. It should be noted that the angle of inclination refers to the slope on the inner surface of the swirler 100 (and the tapered section 120) as it is the slope that determines the operating characteristics of the swirler 100. The tapered section 120 is coupled with the upper section 110 to allow feed introduced into the hydrocyclone to travel between the two sections. To this end, the tapered section 120 and the upper section may be directly connected such that the tapered section 120 continues directly downward from the upper section 110. In this case, the total height (H) of the cyclone 100 may be expressed as H ═ H_up+h_cone。

Both the cone section 120 and the grit chamber 130 may be contained in the lower section 150 of the hydrocyclone 100. The lower section 150 may be coupled to the upper section 110 from below, and may be directly connected to the upper section 110. The upper and/or lower sections 150 may be made of metal. Similarly, the tapered section 120 may be made of metal.

The upper section 110 is connected to the feed inlet 102 such that feed may be introduced into the cyclone 100, in particular into the upper section 110. The feed inlet 102 may be tangentially connected to the upper section 110, allowing tangential entry of feed, imparting a rotational motion to the feed within the cyclone 100. The cyclone 100 is adapted such that feed is introduced under pressure through the feed inlet 102 and, for small cyclones 100, the velocity (v) of the feed at the inlet_in) May be, for example, 2 to 10m/s or 6 to 10 m/s.

The upper section 110 is further connected to an overflow outlet 104 for removing overflow from the cyclone 110, in particular from the upper section 110. Since the overflow outlet 104 typically extends to the upper section 110, e.g. as a vortex finder 106, the free height (H) of the cyclone 100_f) May be less than the total height (H) of the cyclone 100. For embodiments of the invention, the free height may advantageously be expressed relative to the diameter of the upper section 110, in which case the parameter H_fthe/D may be, for example, 3 to 10. It is noted that the total height is measured from the sand trap 130 to the top of the upper section 110 as shown. Accordingly, the free height is measured from the grit chamber 130 to the bottom of the overflow outlet 104. It is further noted that the cyclone 100 may also extend below the grit chamber 130, for example as a skirt leading the underflow discharge. Furthermore, although the grit chamber 130 may be located at the narrowest opening for discharging underflow from the cyclone 100 below the conical section 120, the narrowest opening may also extend vertically with a constant width. Thus, all measurements at the grit chamber 130 are defined herein as being at a level d corresponding to the top of the grit chamber 130_apexTo (3).

The operation of the cyclone 100 can be described as follows. Briefly, the cyclone 100 may be adapted to separate feed materials by using centrifugal forces generated by feed materials entering the cyclone 100 under pressure. Centrifugal forces cause coarse particles to be "thrown" to the inner walls of the cyclone 100, while fine particles remain closer to the center of the cyclone. The overflow outlet 104 or vortex finder 106 draws water and/or fine material into the overflow, while coarse material flows out of a grit chamber 130 at the bottom of the cyclone 100.

The feed creates a complex flow pattern consisting of two spiral paths and one radial path. The outer spiral path at the inner wall of the cyclone 100 spirals towards the conical section 120 of the cyclone 100 and the inner spiral portion spirals towards the overflow outlet 104 (e.g. vortex finder 106). When feed is introduced into cyclone 100, an inward tangential flow will be formed. In such inward flow, the ratio of the tangential force to the drag created by the particles in the feed will control which spiral flow particles will terminate (end). Tangential forces are related to the third power of a particle property metric, such as particle mass, while drag forces are related to the second power (e.g., of the cross-sectional area of the particle). Thus, only fine particles will be transported inwardly to the spiral flow, which transports them to the overflow outlet 104 or vortex finder 106. The coarse particles will remain in the downflow and be directed towards the grit chamber 130. The internal rotating flow has two important features. The innermost part of the stream maintains angular velocity. This results in the formation of a free gas-liquid boundary (e.g., an air core). Thus, the swirler 100 is adapted to shape the air nuclei in the axial dimension of the swirler 100. This air check is critical to the operation of the cyclone 100. The operation of the cyclone 100 can be stable as long as the air core passes through the entire cyclone 100 from the overflow outlet 104 or vortex finder 106 to the grit chamber 130. The air core may then also be directed to the sand trap 130. The flow rate at the grit chamber 130 is relatively high and the underflow can be formed as a conical spray.

When the cyclone 100 is supplied with an excess of coarse material, it may be overloaded. As the mass of the rotating flow increases, maintaining a constant angular velocity begins to require more and more energy. Therefore, the angular velocity decreases, causing unstable air nuclei to start fluctuating. If the overload persists, i.e. excess coarse material continues to be introduced into the cyclone 100, air nuclei may disappear from the bottom of the cyclone 100. At this point, the cyclone 100 begins to develop a stick (roping). Columnar is a condition in which the particle flow velocity is greatly slowed and the underflow capacity is reduced. This will change the rotational and radial flow patterns. The result is that coarse particles are introduced into the internal rotating flow and subsequently carried into the overflow product. The split size of the cyclone 100 becomes much coarser than in normal operation. When the feed contains a high percentage of solids, the operating cut size can rise from well below 100 μm to over 200 μm. Since the speed is greatly reduced, the columnar shape is not a phenomenon that is easily reversed but has a large hysteresis. Thus, returning the cyclone 100 to normal operation may require a substantial reduction in feed.

One characteristic of the columnar shape is the low rotational speed and high percentage of solid matter in the underflow. This makes the underflow look like a column (rope) coming out of the sand settling port 130. Another characteristic of the columnar shape is that the separation size increases and the amount of fine material in the underflow decreases. The sand trap 130 may have a threshold capacity beyond which a columnar state may occur. During normal operation of the cyclone 100, the underflow is ejected from the sand-settling port, typically in a conical pattern. However, at the beginning of the columnar state, the air core inside the sand trap 130 collapses, causing most or all of the spiral motion of the underflow to disappear. The columnar shape may even cause the cyclone 100 to clog. Although cyclone plugging is rare, plugging can occur if large particles, small grinding media or some other foreign object plugs the grit chamber.

The hydrocyclone 100 comprises a plurality of electrodes 140 which are adapted to provide a measurement signal. To detect the columnar shape, the plurality of electrodes 140 are specifically adapted to measure the electrical conductivity inside the cyclone 100 to detect the formation of a columnar state in the cyclone 100. To this end, all electrodes 140 of the plurality of electrodes 140 may be arranged on substantially the same horizontal plane in the axial dimension of the swirler 100. For example, they may be arranged within a range of 1-5cm from each other in the axial dimension. Also, the plurality of electrodes 140 are circumferentially arranged in the conical section 120. The electrodes 140 may be arranged substantially equidistantly along the circumference of the conical section 120. The electrodes may extend through the wall of the hydrocyclone 100, for example, from the inner surface of the conical section 120 to the outer surface of the hydrocyclone 100. The plurality of electrodes 140 may include or be formed from conductive bolts. The plurality of electrodes 140 may include or be formed of a metal. The electrode 140 may be rigid. It has been found that when each of the plurality of electrodes has a thickness of 2-3 millimeters or more, the accuracy and reliability of the measurement can be significantly improved. The plurality of electrodes 140 may be arranged substantially horizontally (i.e., vertically with respect to the axial dimension). The plurality of electrodes 140 may include threads, for example, for securing the electrodes 140. Additionally or alternatively, threads may be used to secure a conductor to the electrode 140 to transmit a measurement signal from the electrode 140. For example, the conductor may be secured between two threaded nuts on the threaded electrode 140.

Importantly, the plurality of electrodes 140 need to be explicitly arranged in the axial dimension such that their axial distance (d) from the sand trap 130_meas) At least the axial distance (i.e., d) between the sand trap 130 and the upper section 110_up-d_apexValue of (d) 5%. At the same time, d_measUp to d_up-d_apex50% of the value. When the upper section 110 and the conical section 120 are directly connected, d_up-d_apexThe value corresponds to the height of the conical section 120. It has been found that having the arrangement of the electrodes within the above limits can significantly improve the accuracy of the columnar detection, even to the extent that a preemptive determination of the transition to the columnar state is achieved using the electrodes 140. Once the plurality of electrodes 140 are arranged above the lower limit as described above, it has been found that the air core becomes more robust for accurate measurements to detect the formation of columnar states in typical measurement situations. On the other hand, it has been found that the predictive effect decreases rapidly in typical measurement situations, once the plurality of electrodes 140 are arranged above the upper limit as described above. Accordingly, arranging the electrodes 140 as described above allows the hydrocyclone 100 to be adapted to proactively detect the formation of a columnar state.

It is noted that the swirler 100 may include one or more sets of the plurality of electrodes 140, such as two, three, or more sets. Each set may be arranged along the circumference of the tapered section 120. The groups being arranged distant from each other in the axial dimensionAnd (4) placing. However, all groups may still be arranged d from the sand-setting mouth 130, measured in the axial dimension_up-d_apexThe value is in the range of 5-50%. The plurality of electrodes 140 in a single group may be arranged on substantially the same horizontal plane in the axial dimension of the swirler 100. For example, they may be arranged within a range of 1-5cm from each other in the axial dimension.

The formation of the columnar state may be determined by measuring conductivity using the apparatus of the present disclosure and correlating the measurements with the formation of the columnar state. For example, repeated measurements may be made using the disclosed apparatus to identify patterns corresponding to the formation of columnar states. The formation of columnar states can be determined from the conductivity measurements based on the fact that: the presence of air nuclei results in the formation of a region within the cyclone 100 in which the electrical conductivity is negligible or significantly reduced. Using the disclosed swirler 100, patterns corresponding to the disappearance of air nuclei may be identified. Further, it has been found that when the plurality of electrodes 140 includes nine or more electrodes, sufficient resolution can be obtained for two-dimensional mapping of air nuclei to detect formation of columnar states. It has further been found that the use of twelve or more electrodes 140 further increases the resolution, so that significant improvements in measurement accuracy and reliability can be obtained.

For example, Electrical Resistance Tomography (ERT) and/or Electrical Impedance Tomography (EIT) may be used to determine the formation of columnar states. These are process tomography techniques that can be used for reliable on-line measurements in multiphase environments. In ERT, an estimate of the target conductivity as a function of position can be calculated from the measured voltage and the known injection current (or vice versa). The calculation is based on a mathematical model that determines the relationship between current, conductivity distribution within the hydrocyclone 100 and voltage on the electrodes. The advantage of ERT is that it is based on a mathematical model that also takes into account the electrode impedance and can be measured very quickly. Thus, multiple electrodes may be suitable for real-time imaging of the underflow of cyclone 100.

Apart from EIT, which makes use of the resistance and reactance of the measurement signal, EIT corresponds to ERT to a large extent, so that the above also applies to EIT. The hydrocyclone 100, and in particular the plurality of electrodes 140, may apply one or both of ERT and EIT measurements to detect the formation of columnar conditions in the hydrocyclone 100.

Regardless of the analysis technique used, the plurality of electrodes 140 may be adapted to provide a measurement signal to detect the formation of columnar states, for example, by detecting the presence or absence of air nuclei between the electrodes 140 or by detecting the size of air nuclei between the electrodes 140. Alternatively or additionally, the plurality of electrodes 140 may be adapted to provide measurement signals to detect whether air nuclei are about to disappear, so that the presence of air nuclei, and thus the columnar state, may be detected preemptively. The plurality of electrodes 140 may be adapted to provide measurement signals for generating a two-dimensional or more-dimensional image of the underflow. The plurality of electrodes 140 may also be adapted to provide a measurement signal from which characteristics of the sand trap 130 may be identified, or the air core may be visualized online.

The measurement signal may be used to control the operation of the hydrocyclone 100. For example, the measurement signal may be used to generate an online warning for an operator of the cyclone 100 even before a columnar state occurs. The measurement signal may be used for automatic control of the cyclone 100, for example to automatically reduce the feed rate when the formation of a columnar state has been detected. This may be done, for example, when it is detected that the stability of the air core has been lost before the columnar state occurs, and the stability may be restored without entering the columnar state. The cyclone 100 may be adapted to be connectable to a controller for analyzing the measurement signal and/or for controlling the cyclone 100 based on the measurement signal. In some embodiments, the cyclone 100 itself may even comprise a controller for analyzing the measurement signal and/or controlling the cyclone 100 based on the measurement signal. The controller may be further adapted to provide an alarm based on the measurement signal, e.g. when formation of a columnar state is detected before and/or after the start of the columnar state.

Fig. 2 a-2 c show a lower section 150 of a hydrocyclone 100 according to an embodiment. The lower section 150 includes the tapered section 120 and an outer surface 152. The outer surface 152 is also generally conical in that it may include one or more frusta segments. However, other shapes are of course possible. The tapered section 120 has an inner surface 122. As mentioned above, the inclination angle (α) of the tapered section 120 corresponds to the inclination angle of the inner surface 122. As described above, the angle may vary along the length of the tapered section 120 or may be fixed. The tapered section 120 may be divided into two or more separate portions 126, 128, including one or more upper portions 126 and one or more lower portions 128 of the tapered section 120. Likewise, the entire lower section 150 may be divided into two or more separate portions, corresponding to the separate portions 126, 128 of the tapered section 120, respectively. The plurality of electrodes 140 may be located between adjacent pairs of upper portions 126 and lower portions 128. To secure the upper portion 126 and the lower portion 128 to each other, the cyclone 100 may include one or more clamps 300. The lower section 150 may include one or more shoulders (shoulders) 154, 156 for supporting the clamp 300 for securing the upper and lower portions 126, 128 to one another. For example, the lower section 150 may include one or more shoulders 154 corresponding to the upper portion 126 and/or one or more shoulders 156 corresponding to the lower portion 128. The one or more shoulders 154, 156 may conform to the outer surface 152 of the lower section 150 in a plane perpendicular to the axial dimension. The one or more shoulders 154, 156 may be annular. The one or more shoulders 154, 156 may extend continuously or discontinuously around the circumference of the lower section 150. The cyclone 100 may include a separate clamp 300 for each pair of upper and lower portions 126, 128. Further, a plurality of electrodes 140 between adjacent pairs of upper and lower portions 126, 128 may be disposed within the gasket 400. Shim 400 may be clamped between adjacent pairs of upper portion 126 and lower portion 128 by clamp 300.

As shown, the sand trap 130 may have a non-zero length in the axial dimension. The width of the sand trap 130 may be kept constant along its length. The cyclone 100 may include a skirt 160 below the grit chamber 130. The skirt 160 may be part of the lower section 150. The skirt 160 is adapted to direct the discharge of the underflow. The skirt 160 may be tapered, and it may include one or more frusta segments. The skirt 160 may be arranged to widen continuously or discontinuously when moving away from the sand trap 130 in the axial dimension.

FIG. 3 shows one example of a clamp 300 for securing the upper portion 126 and the lower portion 128 of the tapered section 120 to each other. The clip 300 may comprise or be made of metal. The clamp 300 may be ring-shaped. The clamp 300 may include collars 310, 312 for applying a clamping force to the lower section 150 of the swirler 100 (e.g., to the shoulders 154, 156). For example, the clamp 300 may include one or more collars 310 for applying a clamping force on a side of the lower section 150 corresponding to the upper portion 126 of the tapered section 120, and/or one or more collars 312 for applying a clamping force on a side of the lower section 150 corresponding to the lower portion 128 of the tapered section 120. The one or more collars 310, 312 may be annular. The one or more collars 310, 312 may be adapted to extend continuously or discontinuously around the circumference of the lower section 150. The clamp 300 may include one or more (e.g., four or more) fasteners 320, such as bolts, for fastening the clamp 320. The one or more fasteners 320 may be arranged to fasten the two collars 310, 312 to each other, for example. The one or more fasteners 300 may be arranged such that the clamping force is applied substantially in the axial dimension of the swirler 100. The clamp 300 may be adapted for waterproof fastening of the conical section 120.

Fig. 4a and 4b illustrate a gasket 400 for protecting the plurality of electrodes 140, e.g. by mechanical and/or electrical insulation. Fig. 4a shows this example in perspective view and fig. 4b shows the same example in perspective view, wherein the outlines of the plurality of electrodes 140 within the pad 400 are shown in dashed lines.

The gasket 400 may be resilient for providing sealing contact. The gasket 400 may be a gasket of an insulating material (e.g., rubber or polyurethane). The gasket 400 may be flat. Which may be adapted to be arranged horizontally. The gasket 400 may be annular. Having an inner boundary 410 adapted to be contacted by feed after it is introduced into cyclone 100 and an outer boundary 412 which may be adapted to face outwardly from lower section 150. The inner boundary 410 and/or the outer boundary 412 may be annular. The gasket 400 may be adapted to at least partially enclose the plurality of electrodes 140. The gasket 400 may have one or more holes for the plurality of electrodes 140. The one or more apertures may extend through the gasket 400, for example, from the inner surface 410 to the outer surface 412. The spacer 400 may be adapted to electrically insulate the plurality of electrodes 140 from one another. The spacer 400 may be adapted to electrically insulate the plurality of electrodes 140 with respect to the tapered section 120 and/or the lower section 150. The plurality of electrodes 140 may be fastened to the spacer 400 by one or more fasteners 420 (e.g., nuts). The thickness of the spacer 400 may be such that each electrode of the plurality of electrodes 140 is insulated on each side by at least a 0.5-1.0 millimeter thick layer of the spacer 400. The outer boundary 412 of the gasket 400 may include one or more extensions 430 for protecting the plurality of electrodes 140. This allows the electrode 140 to be enclosed within the gasket 400 along substantially its entire length, despite the potential contact points. The one or more extensions 430 may be adapted to be disposed in the intermediate space between the one or more fasteners 320 of the clamp 300. This allows the clamp 300 to be vertically secured while the ends of the electrodes 140 of the plurality of electrodes 140 remain open to contact the outer surface 152 of the lower section 150 of the cyclone 100. In other words, the clamp 300 may comprise one or more openings for the one or more extensions 430, which are adapted to bypass the clamp 300 through the openings. This allows for mechanical protection of the electrode 140, e.g. against water and dust, while still making it available for contact, e.g. from the end of the electrode 140. In addition to the above, the one or more extensions 430 may be adapted to indicate proper positioning of the spacer 400, and thus the electrode 140.

The different functions discussed in this disclosure may be performed in a different order and/or concurrently with each other.

Unless otherwise indicated, any range or device value given in this disclosure may be extended or modified without losing the effect sought. Moreover, any embodiment can be combined with another embodiment unless explicitly prohibited.

Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims, and other equivalent features and acts are intended to be within the scope of the claims.

It should be understood that the benefits and advantages described above may relate to one embodiment or may relate to multiple embodiments. Embodiments are not limited to those embodiments that solve any or all of the problems or embodiments having any or all of the benefits and advantages described. It should also be understood that reference to "an" item may refer to one or more of that item.

The term "comprising" is intended in this disclosure to include a particular method, module, or element, but such a module or element does not include an exclusive list, and a method or apparatus may include additional modules or elements.

It should be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this disclosure.