Automatic separator control

Abstract

The present disclosure relates to a method of controlling operation of a centrifugal separator (1), and a separator (1) performing the method. The method comprises monitoring (S101) at least one separation process performance parameter of the separator (1), determining (S102) whether or not a value of said monitored at least one separation process performance parameter attains a set target value, and if not controlling (S104) adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method of controlling operation of a centrifugal separator, and a separator performing the method.BACKGROUND

[0002] Centrifugal separators are generally used for separation of liquids and / or for separation of solids from a liquid mixture. During operation, liquid mixture to be separated in a separation process is introduced into a rotating centrifuge bowl and e.g. heavy particles or denser liquid accumulate at the periphery of the rotating bowl whereas less dense liquid accumulates closer to the central axis of rotation. This allows for collection of the separated fractions, e.g. by means of different outlets arranged at different distances from the rotational axis.

[0003] However, the separation process is highly complex and may be affected by different operating conditions and properties of the supplied liquid mixture that is being separated. Therefore, stable operating conditions are difficult to attain, thus making the controlling of the separator challenging.SUMMARY

[0004] One objective is to solve, or at least mitigate, this problem in the art and thus to provide an improved method of controlling operation of a separator.

[0005] This objective is attained in a first aspect by a method of controlling operation of a centrifugal separator upon the separator performing a separation process. The method comprises monitoring at least one separation process performance parameter of the separator, determining whether or not a value of said monitored at least one separation process performance parameter attains a set target value, and if not controlling adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

[0006] This objective is attained in a second aspect by a centrifugal separator configured to perform a separation process. The centrifugal separator comprises a processing unit being configured to control the centrifugal separator to be operative to monitor at least one separation process performance parameter of the separator, determine whether or not a value of said monitored at least one separation process performance parameter attains a set target value, and if not to control adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

[0007] Advantageously, the proposed method enables dynamic and rapid control of the operation of the separator 1 such that a desired target value is attained for one or more monitored separation process performance parameters to be controlled by adjusting operational parameters of the separator. For example, rotational speed of a bowl of the separator may be controlled such that the light phase turbidity of a supplied liquid mixture maintains a value in a desired target range for a period of time, thus arriving at stable operating conditions.

[0008] In an embodiment, the adjustment of said of at least one operational parameter of the separator continuously is performed such that said at least one separation process performance parameter is maintained at the set target value over time. Thus, the aspects of the invention may provide a self-adjusting system that can try to optimize the separation process in the best possible way and find stable running conditions with different process performance. Thus, the steps of the method may be performed repeatedly during the separation process. Thus, the monitoring, determining and controlling may be performed repeatedly and / or continuously during the separation process.

[0009] In an embodiment, upon determining that the value of said monitored at least one separation process performance parameter attains the set target value, the method comprises maintaining the value of said at least one operational parameter of the separator at its current value. The value may be maintained for a period of time, such as for at least a minute, several minutes or hours, depending on the separation process and the liquid mixture that is separated.

[0010] In an embodiment, the method further comprises monitoring at least one operational parameter of the separator and / or at least one property of a liquid mixture being supplied to the separator, wherein the controlling of the adjustment of the at least one operational parameter of the separator such that the set target value is attained further comprises taking into account the monitored at least one operational parameter of the separator and / or the at least one property of a liquid mixture being supplied to the separator.

[0011] In an embodiment, the method comprises creating a control model based on a plurality of values of said monitored at least one separation process performance parameter and correspondingly adjusted values of said at least one operational parameter, which control model is utilized for controlling the operation of the separator.

[0012] In an embodiment, the method further comprises providing the created control model to a device to which other separators have access, the device being configured to subsequently provide the created control model to the other separators.

[0013] In an embodiment, the method further comprises presenting, to an operator, a plurality of separator operational modes available for selection and receiving, by operator selection, information indicating an order of priority in which the operational modes is to be performed by the separator in response to said user selection, each operational mode prioritizing control of one or more separation process performance parameters of the separator, wherein said at least one operational parameter is controlled to be adjusted to vary within a set allowed range configured to favour an operational mode having higher order of priority.

[0014] In an embodiment, if there is a conflict between one or more separation process performance parameters prioritized by different operational modes, the controlling of the adjustment of at least one operational parameter of the separator affecting the higher prioritized separation process performance should be prioritized such that the corresponding set target value is attained.

[0015] In an embodiment, the method further comprises presenting, to an operator of the separator, said at least one operational parameter being controlled to be adjusted, and the set range in which said at least one operational parameter is allowed to vary.

[0016] In an embodiment, said at least one separation process performance parameter comprises at least one of separator throughput, power consumption, sound level, light phase quality, heavy phase concentration. Further, if e.g. cells are being separated, the viability of the cells being discharged from the separator may be one of said at least one separation process performance parameter.

[0017] In an embodiment, said at least one operational parameter comprises at least one of flowrate of fluid mixture being input to the separator, separator throughput, rotational speed of separator bowl, counter pressure at a light phase outlet or a heavy phase outlet.

[0018] In an embodiment, the set target value of the monitored at least one separation process performance is represented by a target value range. The method may thus comprise controlling adjustment of at least one operational parameter of the separator affecting the monitored at least one separation process performance parameter such that the set target range is attained over time. The target value range may be an interval in which there is stable process conditions for the separation performance parameter.

[0019] In an embodiment, the controlling of the adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained comprises controlling at least two operational parameters of the separator affecting said monitored at least one separation process performance parameter.

[0020] In embodiments, at least two or a plurality of separation process performance parameters are monitored. At least one, or at least two, or a plurality of operational parameters of the separator may thus be adjusted so that the at least two separation process performance parameters are at their set target values or at within their target value ranges over time. Such stable running conditions - i.e. when one or several process performance parameters are mor or less stable over a period of time such as over a period of time that is at least 1 min, such as at least several minutes - may be referred to as a "sweet spot" for the separation process. Since a separation process is a very complex process, the method may in embodiments comprise performing the steps of monitoring, determining and controlling until such a sweet spot is found and later on in the separation process, the steps of monitoring, determining and controlling may be performed until another sweet spot is found.

[0021] In a third aspect, a computer program is provided comprising computer-executable instructions for causing a separator to perform steps recited in the method of the first aspect when the computer-executable instructions are executed on a processing unit included in the separator.

[0022] In a fourth aspect, a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the third aspect embodied thereon.

[0023] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a cross-sectional view of a prior art centrifugal separator in which embodiments may be implemented; Figure 2 shows a more detailed view of a centrifuge bowl of the centrifugal separator of Figure 1; Figure 3 shows a flowchart illustrating a method of controlling a separator in an embodiment; Figure 4 shows a schematic illustration of a processing unit controlling a separator in an embodiment; Figure 5 shows a flowchart illustrating a method of controlling a separator in another embodiment; Figure 6 shows a schematic illustration of a processing unit controlling a separator in another embodiment; Figure 7 shows a schematic illustration of a separator uploading a created control model to a cloud server for distribution to other separators in an embodiment; Figure 8 illustrates a graphical interface showing an order of priority of selected operational modes of a separator in an embodiment; Figure 9 shows a flowchart illustrating a method of controlling a separator in an embodiment; Figure 10 illustrates a graphical interface showing another order of priority of selected operational modes of a separator in an embodiment; Figure 11 illustrates a graphical interface showing still another order of priority of selected operational modes of a separator in an embodiment; Figure 12 illustrates a graphical interface showing yet another order of priority of selected operational modes of a separator in an embodiment; and Figure 13 illustrates a separator according to an embodiment. DETAILED DESCRIPTION

[0025] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0026] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0027] Figures 1 and 2 illustrates a separator 10 to which a control scheme may be applied in an embodiment. As is understood, the control scheme according to embodiments described herein may be applied to any appropriate separator type, such as such as a clarifier, which is a centrifugal separator for solid - liquid separation, a purifier, which is a centrifugal separator for liquid - liquid - solid separation, and a concentrator, which is a centrifugal separator designed to separate three different phases, one solid phase and two liquid phases of different densities, and clean the densest / heaviest liquid phase.

[0028] Figure 1 shows a cross-section of an embodiment of a centrifugal separator 1 configured to separate a heavy phase and a light phase from a liquid mixture. The centrifugal separator 1 has a rotatable part 4, comprising the centrifuge bowl 5 and drive spindle 4a. As is understood, this is just one example of a separator in which embodiments can be implemented.

[0029] The centrifugal separator 1 is further provided with a drive motor 3. This motor 3 may for example comprise a stationary element and a rotatable element, which rotatable element surrounds and is connected to the spindle 4a such that it transmits driving torque to the spindle 4a and hence to the centrifuge bowl 5 during operation. The drive motor 3 may be an electric motor. Alternatively, the drive motor 3 may be connected to the spindle 4a by transmission means such as a drive belt or the like, and the drive motor may alternatively be connected directly to the spindle 4a.

[0030] The centrifuge bowl 5, shown in more detail in Figure 2, is supported by the spindle 4a, which is rotatably arranged in stationary frame 2 around the vertical axis of rotation (X) in a bottom bearing 22 and a top bearing 21. The stationary frame 2 has an upper hood that surrounds centrifuge bowl 5.

[0031] In the centrifugal separator as shown in Figure 1, liquid mixture to be separated is fed to the bottom to the centrifuge bowl 5 by means of inlet feed pump 25 via the drive spindle 4a. The drive spindle 4a is thus in this embodiment a hollow spindle, through which the feed is supplied to the centrifuge bowl 5. However, in other embodiments, the liquid mixture to be separated is supplied from the top, such as through a stationary inlet pipe extending into the centrifuge bowl 5. The pump 25 may be utilized in order to control flowrate of the fluid mixture being input to the separator 1, which thus affects the separator throughput for the supplied fluid mixture.

[0032] After separation has taken place within the centrifuge bowl 5, separated liquid heavy phase is discharged through stationary outlet pipe 6a, whereas separated liquid light phase is discharged through stationary outlet pipe 7a. Valve 23 may be used to control the counter pressure in stationary outlet pipe 7a and valve 24 may be used to control the counter pressure in stationary outlet pipe outlet pipe 6a. These counter pressures may be used to regulate the radial level of the interface between the liquid heavy phase and the liquid light phase within the centrifuge bowl 4.

[0033] Figure 2 shows a more detailed view of the centrifuge bowl 5 of the centrifugal separator 1.

[0034] The centrifuge bowl 5 forms within itself a separation space 9a and a sludge space 9b, located radially outside the separation space 9a. In the separation space 9a, a stack 10 of separation discs is arranged coaxially around the axis of rotation (X) and axially below a top disc 50. The stack 10 is arranged to rotate together with the centrifuge bowl 5 and provides for an efficient separation of the liquid mixture into at least a liquid light phase and a liquid heavy phase. Thus, in the separation space 9a, the centrifugal separation of the liquid mixture takes place during operation. The sludge space 9b is in this embodiment confined between an inner surface of the centrifuge bowl wall 13 and an axially movable operating slide 16.

[0035] The disc stack 10 is supported at its axially lowermost portion by distributor 11. The distributor is arranged to conduct liquid mixture from the centre inlet 14 of the centrifuge bowl 5 to a predetermined radial level in the separation space 9a.

[0036] The inlet 14 is arranged for receiving the liquid mixture and is designed as a central inlet chamber formed within or under the distributor 11. The inlet 14 communicates with the separation space 9a via passages 17 formed in the distributor 11.

[0037] A number of outlet conduits 30 in the form of channels or pipes are configured to transport separated liquid heavy phase from the sludge space 9b to the second outlet 6. Such liquid heavy phase may comprise some solids as well. In Figure 2, the outlet conduits 30 are formed as pipes having their inlet end portions 31 stretching out in the sludge space 9b to a diameter larger than the disc stack diameter. The outlet conduits 30 have their inlet end portions 31 extending into the sludge space 9b. The outlet conduits 30 extend from a radially outer position of the sludge space 9b to the second outlet 6. The outlet conduits 30 consequently have their inlet end portions 31 arranged at the radially outer position and a conduit outlet 32 arranged at a radially inner position. The outlet conduits are arranged axially above the top disc 50 and in close proximity of the surrounding upper inner wall of the centrifuge bowl 5. Further, the outlet conduits 30 are arranged with an upward tilt relative the radial plane from the inlet end portions 31 to the conduit outlet 32.

[0038] In embodiments, the centrifuge bowl 5 comprises at least four outlet conduits 30. However, the centrifuge bowl 5 may comprises a single outlet conduit. In other embodiments, the centrifuge bowl is free of outlet conduits 30, and separated liquid heavy phase may flow more freely above the top disc 50 to the second outlet chamber 6.

[0039] The radially inner portion of the disc stack 10 communicates with a first outlet 7 for a separated light phase of the liquid mixture. This first outlet 7 of the centrifuge bowl 5 communicates with a stationary outlet pipe 7a for discharging the separated liquid light phase from the centrifuge bowl 5.

[0040] The first and second outlet chambers 6, 7 are mechanically sealed with seals 12a, 12b. As this is an airtight design, the seals are commonly referred to as hermetic seals. The inlet channel 4b is also sealed at lower end of the hollow spindle 4a, thus preventing communication between the inlet channel 4b and the surroundings. This mechanical seal is not shown in the Figures.

[0041] In this example, the centrifuge bowl 5 is further provided with outlets 15 at the radially outer periphery of the sludge space 9b. These outlets 15 are evenly distributed around the rotor axis (X) and are arranged for intermittent discharge of a sludge component of the liquid mixture. The opening of the outlets 15 is controlled by means of an operating slide 16 actuated by operating water channels below the operating slide 16, as is known in the art. In its position shown in the drawing, the operating slide 16 abuts sealingly at its periphery against the upper part of the centrifuge bowl 5, thereby closing the sludge space 9b from connection with outlets 15, which are extending through the centrifuge bowl 5.

[0042] During operation of the separator as shown in Figure 1 and 2, the centrifuge bowl 5 is brought into rotation by the drive motor 3. Via the spindle 4a, liquid mixture to be separated is brought into the separation space 9a, as indicated by arrow "A". Depending on the density, different phases in the liquid mixture is separated between the separation discs of the stack 10. Heavier component, such as a liquid heavy phase and a sludge phase, move radially outwards between the separation discs of the stack 10 to the sludge space 9b, whereas the phase of lowest density, such as a liquid light phase, moves radially inwards between the separation discs of the stack 10 and is forced through the outlet pipe 7a via the first outlet 7, as indicated by arrow "C". The liquid of higher density is instead discharged via the outlet conduits 30 to the second outlet 6 and further out via stationary outlet pipe 6a, as indicated by arrow "B". Solids, or sludge, which accumulate at the periphery of the sludge space 9b and is emptied intermittently from within the centrifuge bowl by the sludge outlets 15 being opened, whereupon sludge is discharged from the separation chamber 15 by means of centrifugal force, as indicated by arrow "D". However, the discharge of sludge may also take place continuously, in which case the sludge outlets 15 take the form of open nozzles and a certain flow of sludge and / or heavy phase is discharged continuously by means of centrifugal force.

[0043] Now, the separator 1 may be configured to control one more specific separation process performance parameters depending on a desired output / performance to be achieved by the separator.

[0044] For instance, in case a particular target value or range of a specific separation process performance parameter of the separator 1, such as e.g. separator throughput, is desired for the fluid mixture being supplied to the separator 1 via the inlet pipe 4a, then an operational parameter of the separator 1 affecting said specific performance parameter (i.e. separator throughput) needs to be carefully controlled. In an example where the separator output parameter to attain a particular target value is embodied in the form of separator throughput, an operational parameter such as e.g. flowrate of the supplied fluid mixture may be controlled by adjusting inlet feed pump 25. Typically, if it is desired that the separator throughput is to attain a high target value, the flowrate of the supplied fluid mixture must typically be controlled to be high, thereby requiring the pump 25 at the inlet channel 4b to be operated at a high speed.

[0045] In another example, a process performance parameter in the form of turbidity is to be controlled to attain a desired target value or range. For instance, if the separated liquid being discharged through the stationary outlet pipe 7a is to be clear and thus have a low turbidity, the separator will typically operate the centrifuge bowl 5 at a high rotational speed to effectively separate the two liquid phases and any solids from each other.

[0046] As is understood, in order to attain separated liquid having a low turbidity, it may further be necessary to reduce the flowrate of the fluid mixture being supplied via the inlet pipe 4a to allow the separator to thoroughly separate the liquid and the solids from the supplied fluid mixture. Hence it may be practically difficult to attain a high separator throughput and a low turbidity for the separated liquid light phase at the same time, i.e. during one and the same operational mode of the separator 1.

[0047] In a further example, sustainability measures in the form of e.g. energy consumption and operating sound level of the separator 1 may be taken into account as process performance parameters, which may be incompatible with both high throughput and low turbidity of the light phase. As is understood, other parameters for determining light phase quality other than light phase turbidity may be envisaged such as the purity of the light phase, or some other parameter related to concentration of the heavy phase or degree of particles in (or visibility / permeability of) the separated light phase.

[0048] Hence, in the above three examples where separation process performance parameters in the form of (a) separator throughput, (b) turbidity of separated liquid and (c) separator energy consumption are to attain desired target levels or ranges, one or more separator operating parameters (e.g. flowrate of the supplied fluid mixture, rotational speed of the bowl 5, etc.) needs to be a carefully controlled. This is challenging and typically managed by an operator of the separator 1 performing appropriate adjustments.

[0049] As can be concluded, there are many challenges to overcome when operating a separator such as the centrifugal separator 1 illustrated with reference to Figures 1 and 2.

[0050] Figure 3 illustrates a flowchart of a method of controlling operation of a centrifugal separator 1 upon the separator performing a separation process according to an embodiment.

[0051] In this exemplifying embodiment, it is assumed that the separation process performance parameter to be controlled is light phase turbidity. Thus, it is desired to attain a liquid light phase which is clear and thus has a low turbidity when exiting via the outlet pipe 7a. On the other hand, it may not be desirable to have a too low turbidity. For instance, assuming that the separator 1 is utilized at a brewery for brewing a product such as beer; it may then be desirable to have a fairly clear light phase liquid (i.e. beer) exiting the outlet pipe 7a while still maintaining some amount of yeast and flavouring agents in the beer.

[0052] In this example, a target value of 50 NTU ("Nephelometric Turbidity Unit") is desired for the separated liquid exiting the separator 1 via the outlet pipe 7a, which is the unit used to measure the turbidity of a fluid (i.e. the presence of suspended particles in the fluid). In other words, the higher the concentration of suspended solids in the fluid is, the cloudier the fluid looks and the higher the turbidity is.

[0053] Further, it may be that a desired target range is set around the target value of 50 NTU, where preferably the light phase turbidity should be in the range of 45-55 NTU.

[0054] It is further assumed that the operational parameter to be controlled for the separator 1 to attain the desired target value for the light phase turbidity is embodied in the form of rotational speed of the bowl 5. Commonly, it may be important that the rotational speed of the bowl 5, as measured in rpm ("rotations per minute"), is allowed to be controlled up to a high value, since a high rotational speed of the bowl 5 generally results in low turbidity of the separated liquid.

[0055] In other words, it may be that a separator operational parameter (e.g. bowl rotational speed) is controlled such that a selected separation process performance parameter (e.g. light phase turbidity) narrowly attains a specific value of, say, 50 NTU, or that a broader range is acceptable, such as 45-55 NTU. Thus, the set target value of the separation process performance parameter may represent a specific value or, which is more common in practice, a range of values; in this embodiment exemplified by the range 45-55 NTU. Thus, a requirement may be that the separation process performance parameter is stable over time within a set range.

[0056] Reference will further be made to Figure 4 illustrating a controller 35 configured to control the separator 1 according to an embodiment. As is understood, this controller 35 may be a stand-alone component arranged remotely from - but in communicative connection with - the separator 1, but may alternatively be embedded in the separator 1 for separator control. In Figure 4, the controller 35 is referred to as a central processing unit (CPU) and may be embodied in the form of one or more microprocessors. As is understood, the communicative connection of the controller 35 with the separator 1 may be wired or wireless.

[0057] As shown in Figure 3, in a first step S101, the CPU 35 monitors one or more separator process performance parameters to be controlled. As mentioned, in this particular example, the CPU 35 is configured to monitor and control the light phase turbidity (LPT), i.e. the turbidity of the separated liquid being output from the separator via the outlet pipe 7a.

[0058] In S102, the CPU 35 determines whether or not the light phase turbidity is within the desired target range of 45-55 NTU. If so, the target range is indeed attained and the rotational speed of the bowl 5 is maintained accordingly in S103. In this particular example, the speed of the bowl 5 is assumed to be maintained at 5000 rpm. In other words, in this embodiment, controlling of at least one operational parameter such that a light phase turbidity is maintained within the desired target range of 45-55 NTU for a certain period of time is considered to constitute a "sweet spot" for the separation process that the separator controlling strives to achieve.

[0059] However, should the CPU 35 determine in S102 that the light phase turbidity is not within the desired target range of 45-55 NTU, such as e.g. at 43 NTU, the CPU 35 will accordingly decrease the rotational speed of the bowl 5 in S104 in order to increase the turbidity of the separated liquid, thus resulting in more particles being present in the separated liquid. The bowl speed is exemplified to be decreased to 4750 rpm, eventually resulting an increase in the light phase turbidity to reach the desired target range of 45-55 NTU.

[0060] In contrast, should the CPU 35 determine in S102 that the currently value of the light phase turbidity is above the desired target range of 45-55 NTU, such as e.g. at 57 NTU, the CPU 35 will accordingly increase the rotational speed of the bowl 5 in S104 in order to decrease the turbidity of the separated liquid, thus resulting in a less amount of particles being present in the separated liquid. The bowl speed is exemplified to be increased to 5250 rpm in order to cause the light phase turbidity to arrive at the desired target range of 45-55 NTU.

[0061] Advantageously, the proposed method enables dynamic and rapid control of the operation of the separator 1 such that a desired target value is attained for one or more monitored separation process performance parameters to be controlled. In this example, the rotational speed of the bowl 5 is controlled such that the light phase turbidity maintains a value in the desired target range of 45-55 NTU for a period of time, thus arriving at stable operating conditions (the above-mentioned separation process "sweet spot").

[0062] Generally, as illustrated in Figure 3, the adjustment of the operational parameter of the separator is continuously performed (i.e. increasing or decreasing the bowl speed) such that the separation process performance parameter is maintained in the set target range (i.e. the light phase turbidity is maintained in the desired target range of 45-55 NTU) over time, which advantageously provides for stable separator operating conditions throughout the separation process.

[0063] In the example described with reference to Figure 3, there may be numerous reasons why the value of the monitored performance parameter of the separator suddenly or gradually changes and eventually deviates from the desired target range. A commonly occurring reason is that a property of the liquid mixture being input to the separator 1 via the inlet 14 changes.

[0064] For instance, if the composition of the liquid mixture being input to the separator 1 via the inlet 14 changes such that a greater amount particles are present in the liquid mixture supplied to the separator 1, the rotational speed of the bowl 5 should generally be increased to maintain the light phase turbidity at the desired target value of around 50 NTU (i.e. in the range of 45-55 NTU). If not, the light phase turbidity of the separated liquid will typically increase with the increasing amount of particles being present in the liquid mixture supplied to the separator 1 via the inlet 14.

[0065] In another example, an operational parameter of the separator may be adjusted, either by the CPU 35 or manually by an operator. For instance, if the inlet feed pump 25 is controlled such that the flowrate of the liquid mixture being supplied to the separator 1 via the inlet 14 increases or decreases, the rotational speed of the bowl 5 should typically be increased or decreased, respectively, to maintain the light phase turbidity at the desired target value of around 50 NTU.

[0066] Thus, the change in the monitored process performance parameter (i.e. the light phase turbidity) is commonly a result of a change in the composition of the liquid mixture or in a change in an operational parameter of the separator 1, such as e.g. a change in the flowrate with which the liquid mixture is supplied to the separator 1 (as adjusted by the inlet feed pump 25). As a result, the selected separator operational parameter may every now and then have to be adjusted such that the desired target value is arrived at for the monitored process performance parameter. However, once the desired target value is arrived at, the operational parameter of the separator 1 is generally maintained at a nominal value (in the above example represented by a bowl speed of 5000 rpm).

[0067] It may further be envisaged that a plurality of operational parameters are adjusted for a monitored process performance parameter to attain a desired target range. For instance, with reference to the examples hereinabove, it may be that the rotational speed of the bowl 5 is adjusted for the light phase turbidity to attain a value in the range of 45-55 NTU. Then, after a while, if for instance the light phase turbidity increases (or decreases), the CPU 35 may choose to decrease (or increase) the flowrate with which the liquid mixture is supplied to the separator 1, rather than adjusting the bowl speed, such that the light phase turbidity again attains a value in the range of 45-55 NTU. As is understood, it may be envisaged that both the rotational speed of the bowl 5 and the flowrate are adjusted more or less simultaneously for having the light phase turbidity attain a value in the range of 45-55 NTU rather than in sequence.

[0068] Moreover, it is envisaged that more than one process performance parameter is monitored. Assuming for instance that the light phase turbidity is monitored to attain a target value range of 45-55 NTU as described hereinabove, it may further be that another process performance parameter is monitored, such as energy consumption of the separator 1. Hence, if e.g. the light phase turbidity needs to be increased, it may be that the flowrate is increased rather than increasing the rotational speed of the bowl 1, if an increase in rotational speed would result in the energy consumption increasing outside of an allowable target energy consumption range. Thus, the method may comprise controlling a plurality of operational parameters such that several process performance parameters are kept within their respective target ranges for a period of time, thus arriving at stable operating conditions (a "sweet spot").

[0069] Figure 5 illustrates a flowchart of a method of controlling operation of a centrifugal separator 1 upon the separator performing a separation process according to a further embodiment.

[0070] Reference will further be made to Figure 6 illustrating the controller 35 configured to control the separator 1 according to the method of Figure 4 in an embodiment.

[0071] As previously described, in first step S101, the CPU 35 monitors the light phase turbidity (LPT), i.e. the turbidity of the separated liquid being output from the separator via the outlet pipe 7a.

[0072] Further, in this embodiment, the CPU 35 determines in S101a a current flowrate with which the liquid mixture is supplied by the inlet feed pump 25 to the separator 1 via the inlet 14. As is understood, the CPU 35 may from the inlet feed pump 25 acquire the current flowrate of the supplied liquid mixture being supplied, which flowrate is adjusted by the inlet feed pump 25.

[0073] In S102, the CPU 35 determines whether or not the light phase turbidity is within the desired target range of 45-55 NTU. If so, the target range is indeed attained and the rotational speed of the bowl 5 is maintained accordingly in S103 at 5000 rpm.

[0074] However, should the CPU 35 determine in S102 that the light phase turbidity is not within the desired target range of 45-55 NTU, such as e.g. at 43 NTU, the CPU 35 will accordingly decrease the rotational speed of the bowl 5 in S104 in order to increase the turbidity of the separated liquid, thus resulting in more particles being present in the separated liquid.

[0075] Additionally, in this embodiment, the CPU 35 will not only take the monitored light phase turbidity into account upon adjusting the currently set bowl speed in S104, but further the currently monitored flowrate of the supplied liquid mixture.

[0076] In this example, it is assumed that if the monitored flowrate (FR) has a first value F1 in one scenario while having a second, higher value F2 in another scenario (for the same light phase turbidity of 43 NTU), then the higher flowrate F2 will result in a slightly lower decrease in bowl speed being performed by the CPU 35 as compared to a scenario where the liquid mixture is supplied with the lower flowrate F1, the rationale being that a higher flowrate F2 eventually will result in a higher light phase turbidity as compared to a lower flowrate F1 for the same bowl speed.

[0077] Thus, given that the light phase turbidity is at 43 NTU, the CPU 35 will in S104 decrease the bowl speed to, say, 4850 rpm for a flowrate of the supplied liquid mixture of F2, while decreasing the bowl speed to 4750 rpm for a flowrate of the supplied liquid mixture of F1. Advantageously, this provides for a more dynamic and accurate control of the separator operational parameters (i.e. bowl rotational speed) in order to attain a desired target value for a monitored separation process performance parameter (i.e. light phase turbidity).

[0078] In an embodiment, machine-learning (ML) and / or artificial intelligence (AI) may be applied by the CPU 35 upon controlling the operation of the separator for creating a control model utilized for controlling operation of the separator 1 performing a separation process. For instance, with reference to the above examples, the CPU 35 may during operation of the separator conclude that the operational parameters should be adjusted according to settings of Table 1, where possibly the CPU 35 may be configured to extrapolate between the monitored values of the desired process performance parameter, thus concluding from the extrapolation that e.g. a light phase turbidity of for instance 45 NTU would result in the rotational bowl speed being adjusted to around 4820 rpm. Table 1. Settings applied during creating of a control model at the CPU.Light phase turbidity (NTU)Set rotational bowl speed (rpm)434750505000575250

[0079] Thus, in this embodiment, the CPU 35 will set up a control model based on the monitored process performance parameters and the corresponding operational parameters, which control model is applied by the CPU 35 when operating the separator 1 in order to advantageously provide dynamic and accurate control of the operation of the separator 1, as described above.

[0080] Further advantageous is that such control model may be shared among other separators such that an already established and tested control model can be applied at numerous other separators.

[0081] Hence, as shown in Figure 7, after the first separator 1a (having the CPU embedded) has created the control model in S201, the first separator 1a uploads the created control model to a remote server 40 (e.g. over the Internet) in S202 to which numerous other separators 1a, 1b, ..., in have access. These other separators 1a, 1b, ..., in may thus in S203 advantageously acquire an already created and accurate control model from the server 40. This is particularly advantageous upon initial configuration of the separators 1a, 1b, ..., 1n. During operation, it may be envisaged that one or more of the separators 1a, 1b, ..., in (such as e.g. second separator 1b) slightly adjusts the control model acquired in S203 to better fit the control process carried out locally at the separator ib. Even so, the control model initially acquired in S203 is of great benefit for the second separator 1b during a configuration phase.

[0082] Figure 8 illustrates an embodiment of a method of controlling operation of the centrifugal separator 1, where a user / operator of the separator 1 is allowed to select from a number of predetermined operational modes which separation process performance parameter(s) to prioritize.

[0083] Now, the separator 1 maybe controlled to operate in different operational modes depending on a desired output to be achieved by the separator, where each mode will favour a specific separation process performance parameter.

[0084] Reference will further be made to Figure 9 showing a flowchart illustrating the method of controlling operation of the centrifugal separator 1 according to the embodiment discussed with reference to Figure 8.

[0085] In this embodiment, a specific operational mode will be performed by the separator 1 depending on certain functionality to be attained during the separation process, where typically the specific operational mode indicates that control of a desired separation process performance parameter is to be favoured before another performance parameter. For instance, in case a low-energy operational mode is performed to favour a low energy consumption of the separator 1, an operational parameter in the form of the rotational speed of the bowl 5 is typically controlled to be low while if a low-turbidity operational mode is performed, the rotational speed of the bowl 5 is typically controlled to be high in order to favour low turbidity of the light phase.

[0086] In an embodiment, the operator may indicate via a user interface, such as a display of the separator or a control device such as a smart phone or a tablet, for which particular application the separator 1 is to be utilized. In this example, the separator is to be used in a brewery application, where for instance sludge in the form of yeast / mash is to be separated from the beer being brewed. Clarified beer is separated as the liquid light phase (C) and yeast is separated and discharged in a liquid heavy phase (B). However, with large volumes of yeast, some may be discharged via the sludge outlets 15 (D).

[0087] Hence, when the user selects the brewery application, the separator 1 will present four operational modes to the operator: "Light phase turbidity", "Heavy phase concentration", "Product flow" and "Energy & Sound" where, as the names imply: (a) the light phase turbidity (LPT) operational mode controls operational parameters of the separator 1 to attain and favour a liquid light phase - i.e. the separated beer - which is clear and thus has a low turbidity when exiting via the outlet pipe 7a, (b) the heavy phase concentration (HPC) operational mode controls operational parameters of the separator 1 to attain a liquid heavy phase (i.e. the separated liquid phase comprising yeast) which has a high concentration and thus is compact upon being discharged via the outlet pipe 6a. (c) the throughput operational mode controls operational parameters of the separator 1 to attain a high throughput for the liquid mixture passing through the separator, and (d) the energy and sound (E&S) operational mode controls operational parameters of the separator 1 to attain a low energy consumption and sound level upon the separator 1 is performing a separation process.

[0088] In other words, the operational modes selected in the above examples will prioritize, and thus favour, the following separation process performance parameters: (a) low light phase turbidity, (b) high heavy phase concentration, (c) high liquid mixture throughput and (d) low energy consumption / sound levels, respectively.

[0089] Thus, in a first step S100a, a plurality of separator operational modes available for selection is presented to the operator, in this example the four different modes (a)-(d) discussed hereinabove.

[0090] When presented with the four different operational modes available for selection for the particular application ("brewery") in S100a, the operator selects in S100b in which order the operational modes are to be prioritized when the separator 1 starts the separation process. For instance, the operator may perform ordering of the operational modes via e.g. a touch-screen display of the separator 1.

[0091] In this particular example, the light phase turbidity mode is given the highest priority, followed by heavy phase concentration mode and the product flow mode, while the energy and sound mode is given the lowest priority, as illustrated in Figure 8.

[0092] In this example, the operator is further allowed to state a desired product flow of 20 m 3< / h with a maximum deviation of ± 5 m 3< / h to be applied by the separator 1 during the performed separation process and a desired turbidity of 50 NTU, with an allowed range for the turbidity of 45-55 NTU, for the separated liquid (i.e. the beer) exiting the separator 1 via the outlet pipe 7a.

[0093] Hence, in S100b the separator 1 receives, by the operator selection, information indicating an order of priority in which the operational modes is to be performed by the separator 1 in response to the selection.

[0094] In response to the information received from the operator indicating the selected priority for the operational modes in S100b, the separator 1 monitors in S101 performance parameters of the separator 1 associated with the operational modes, to ensure that their desired target values are attained upon controlling adjustment in S104 of one or more operational parameters affecting the monitored separation process performance parameters such that the set target values are attained upon the separator 1 performing the prioritized operational mode during the separation process, the highest-priority operational mode in this example being the light phase turbidity operational mode.

[0095] The separation performance parameters monitored in S101 are hence in this exemplifying embodiment (a) light phase turbidity, (b) heavy phase concentration, (c) liquid mixture throughput and (d) energy consumption / sound levels.

[0096] The operational parameters determined to be controlled in S104 to cause performance parameters (a)-(d) to attain their target values are indicated with three meters shown in a right-hand section of Figure 8, namely product flow, rotational speed of the bowl 5 and light phase counter pressure.

[0097] As can be seen in the right-hand section of Figure 8, giving the highest priority to the light phase turbidity operational mode implies that the range of values within which the product flow can be adjusted in S104 during the separation process is fairly broad, from about 16 to 24 m 3< / h. In other words, to maintain a low turbidity for the separated liquid, the separator 1 must be able to decrease the product flow and thus the separator throughput such that the rotation of the rotational bowl 5 causes a thorough separation of the mash / yeast from the liquid mixture supplied to the separator 1 in order to achieve a low turbidity for the separated liquid.

[0098] In this example, since the throughput only is prioritized as the third operational mode after light phase turbidity and heavy phase concentration, the separator 1 has greater degrees of freedom for product flow as an operational parameter to attain a desired turbidity.

[0099] Further, as illustrated in the second meter below the product flow meter indicating rotational speed of the bowl 5, it is important that the rpm ("rotations per minute") of the bowl 5 is allowed to be controlled up to its maximum value of 6250 rpm in the light phase turbidity operational mode, since a high rotational speed of the bowl 5 generally results in low turbidity of the separated liquid.

[0100] Moreover, as shown in the third meter indicating light phase counter pressure, which controls the counter pressure on the liquid light phase outlet; similar to the product flow, this is allowed to be controlled in a relatively broad range of values ranging from 1 to 8.5 bar, which while not being particularly important for the light phase turbidity operational mode indeed is required to attain a heavy phase concentration being the second-highest prioritized operational mode.

[0101] A high light phase counter pressure provides for achieving a high concentration of the heavy phase, if needed. For example, a high rotational speed of the bowl in combination with a low product flow may result in a high concentration of the heavy phase within the bowl, and a high light phase counter pressure may then aid in discharging such highly concentrated heavy phase.

[0102] As further can be concluded from Figure 8, both the product flow and the rotational speed of the bowl 5 is allowed to be controlled up to high parameter values, which generally is not beneficial for energy consumption and sound level, which is in line with the energy and sound operational mode being least prioritized in this example.

[0103] Thus, if in a scenario where e.g. performance parameter (c) ("throughput") cannot be controlled to reach its target value without also performance parameter (a) ("light phase turbidity") failing to reach its target value, control of the light phase turbidity will be prioritized in S104. In other words, it may be that the process is controlled such that the light phase turbidity reaches its target value while the throughput will not.

[0104] Figure 10 illustrates a further embodiment, where the operator in S100b indicates a different order of priority in which the operational modes is to be performed by the separator 1.

[0105] In this particular example, throughput mode is given the highest priority, followed by the energy and sound mode and the light phase turbidity mode, while the heavy phase concentration mode is given the lowest priority.

[0106] In this example, the operational parameters to be controlled in S104 are the same as in the previous example, albeit with differently assigned ranges. As is understood, the examples described herein are for brevity illustrated to control (the same) three parameters while in a practical scenario, tens of operational parameters may be controlled and different operational parameter may be controlled for differently prioritized operational modes.

[0107] As can be seen in the right-hand section of Figure 10, giving the highest priority to the product flow operational mode implies that the range of values that can be controlled in S104 for the product flow will be set relatively narrow from about 19 to 21 m 3< / h, giving an accurate and well-predictable range for the product flow, which is desired by the operator when the throughput mode is given the highest priority.

[0108] Further, as illustrated in the second meter below the product flow meter indicating rotational speed of the bowl 5, the rotation speed of the bowl 5 is kept fairly low in the range 4000-4750 rpm, which is in compliance with the second-highest prioritized energy mode and the third-highest mode being the light phase turbidity mode. In other words, a low rotational speed will result in a low energy consumption and a relatively silent separator operation. Further, since the light phase turbidity mode has a low priority, it is not necessary for the separator 1 to rotate the bowl 5 at a high rpm.

[0109] The third meter indicating a low light phase counter pressure will further be beneficial for low energy consumption, and since the heavy phase concentration is the least prioritized operational mode of the four modes, it is not necessary for the separator 1 to be able to provide a high light phase counter pressure.

[0110] Hence, as can be concluded, with the differently set ranges for the operational parameters, the new prioritization of Figure 10 (as compared to that of Figure 8) will advantageously be favoured by the separator and the characteristics associated with the throughput mode will be provided with the separator control, such as e.g. an accurate and predictable product flow range.

[0111] Figure 11 illustrates still a further embodiment, where the operator in S100b indicates still a different order of priority in which the operational modes is to be performed by the separator 1.

[0112] In this particular example, light phase turbidity mode is given the highest priority, followed by the energy and sound mode and the throughput mode, while the heavy phase concentration mode again is given the lowest priority.

[0113] As can be seen in the right-hand section of Figure 11, giving the highest priority to the light phase turbidity operational mode implies (as in Figure 8) that the range of values that can be controlled in S104 for the product flow is fairly broad, from about 16 to 24 m 3< / h. In other words, as in the example of Figure 8, to maintain a low turbidity for the separated liquid, the separator 1 must be able to decrease the product flow and thus the separator throughput such that the rotation of the rotational bowl 5 causes a thorough separation of the mash / yeast from the liquid mixture supplied to the separator 1 in order to achieve a low turbidity for the separated liquid.

[0114] However, in contrast to the operational parameter settings of Figure 8, since the energy and sound mode in this example is the second-highest prioritized mode, the rotational speed of the bowl 5 is allowed to increase to a value of 5500 rpm, rather than to 6250 rpm as was the case in Figure 8.

[0115] Further, since the heavy phase concentration mode is the least prioritized mode, the light phase counter pressure is kept low at 1-2.5 bar, which is further beneficial for the energy and sound mode.

[0116] Figure 12 illustrates a fourth exemplifying embodiment, where the operator in S100b indicates yet a different order of priority in which the operational modes is to be performed by the separator 1.

[0117] In this particular example, heavy phase concentration mode is given the highest priority, followed by the throughput mode and the light phase turbidity mode, while the energy and sound mode is given the lowest priority.

[0118] As can be seen in the right-hand section of Figure 12, giving the highest priority to the heavy phase concentration operational mode and the second-highest priority to the throughput mode indicates that the product flow will be set relatively narrow from about 18 to 22 m 3< / h, giving a relatively accurate and well-predictable range for the product flow, which is desired by the operator when the throughput mode is given the second highest priority. However, as compared Figure 10 where the throughput mode was given the highest priority, the set range of the product flow is somewhat wider (i.e. 18-22 m 3< / h rather than 19-21 m3 / h), since a more varying product flow typically is required for attaining high heavy phase concentration, being the highest-priority mode.

[0119] Further, while the range of the rotational speed of the bowl 11 is the same as that being set in Figure 11, the range of the light phase counter pressure must be greatly widened. In this example, the range of the light phase counter pressure is set to 1-10 bar, which may be necessary in order to be able to discharge a high heavy phase concentration at different conditions and applications.

[0120] It should be understood that the ranges for the values of the operational parameters illustrated in the three meters in the right-hand part of Figure 8 and 10-12 not necessarily are displayed to the operator but may be set and kept internally in the separator 1.

[0121] Figure 13 illustrates a separator 1 according to an embodiment, where the steps of the method of controlling operation of the separator upon the separator performing a separation process in practice are performed by previously mentioned processing unit 35 with which the separator 1 is equipped, the processing unit 35 being embodied in the form of one or more microprocessors arranged to execute a computer program 36 downloaded to a storage medium 37 associated with the microprocessor, such as a Random Access Memory (RAM), a Flash memory or a hard disk drive. The processing unit 35 is arranged to cause the separator 1 to carry out the method according to embodiments when the appropriate computer program 36 comprising computer-executable instructions is downloaded to the storage medium 37 and executed by the processing unit 35. The storage medium 37 may also be a computer program product comprising the computer program 36. Alternatively, the computer program 36 may be transferred to the storage medium 37 by means of a suitable computer program product, such as a Digital Versatile Disc (DVD) or a memory stick. As a further alternative, the computer program 36 may be downloaded to the storage medium 37 over a network. The processing unit 35 may alternatively be embodied in the form of a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), etc. The separator 1 may further comprise a communication interface 38 (wired and / or wireless) over which the separator 1 is configured to transmit and receive data.

[0122] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

[0123] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Examples

Embodiment Construction

[0025]The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0026]These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0027]Figures 1 and 2 illustrates a separator 10 to which a control scheme may be applied in an embodiment. As is understood, the control scheme according to embodiments described herein may be applied to any appropriate separator type, such as such as a clarifier, which is a centrifugal separator for solid - liquid separation, a purifier, which is a centrifugal separator for liquid - liquid - solid separation, and a concentrator,...

TECHNICAL FIELD

[0001] The present disclosure relates to a method of controlling operation of a centrifugal separator, and a separator performing the method.BACKGROUND

[0002] Centrifugal separators are generally used for separation of liquids and / or for separation of solids from a liquid mixture. During operation, liquid mixture to be separated in a separation process is introduced into a rotating centrifuge bowl and e.g. heavy particles or denser liquid accumulate at the periphery of the rotating bowl whereas less dense liquid accumulates closer to the central axis of rotation. This allows for collection of the separated fractions, e.g. by means of different outlets arranged at different distances from the rotational axis.

[0003] However, the separation process is highly complex and may be affected by different operating conditions and properties of the supplied liquid mixture that is being separated. Therefore, stable operating conditions are difficult to attain, thus making the controlling of the separator challenging.SUMMARY

[0004] One objective is to solve, or at least mitigate, this problem in the art and thus to provide an improved method of controlling operation of a separator.

[0005] This objective is attained in a first aspect by a method of controlling operation of a centrifugal separator upon the separator performing a separation process. The method comprises monitoring at least one separation process performance parameter of the separator, determining whether or not a value of said monitored at least one separation process performance parameter attains a set target value, and if not controlling adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

[0006] This objective is attained in a second aspect by a centrifugal separator configured to perform a separation process. The centrifugal separator comprises a processing unit being configured to control the centrifugal separator to be operative to monitor at least one separation process performance parameter of the separator, determine whether or not a value of said monitored at least one separation process performance parameter attains a set target value, and if not to control adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

[0007] Advantageously, the proposed method enables dynamic and rapid control of the operation of the separator 1 such that a desired target value is attained for one or more monitored separation process performance parameters to be controlled by adjusting operational parameters of the separator. For example, rotational speed of a bowl of the separator may be controlled such that the light phase turbidity of a supplied liquid mixture maintains a value in a desired target range for a period of time, thus arriving at stable operating conditions.

[0008] In an embodiment, the adjustment of said of at least one operational parameter of the separator continuously is performed such that said at least one separation process performance parameter is maintained at the set target value over time. Thus, the aspects of the invention may provide a self-adjusting system that can try to optimize the separation process in the best possible way and find stable running conditions with different process performance. Thus, the steps of the method may be performed repeatedly during the separation process. Thus, the monitoring, determining and controlling may be performed repeatedly and / or continuously during the separation process.

[0009] In an embodiment, upon determining that the value of said monitored at least one separation process performance parameter attains the set target value, the method comprises maintaining the value of said at least one operational parameter of the separator at its current value. The value may be maintained for a period of time, such as for at least a minute, several minutes or hours, depending on the separation process and the liquid mixture that is separated.

[0010] In an embodiment, the method further comprises monitoring at least one operational parameter of the separator and / or at least one property of a liquid mixture being supplied to the separator, wherein the controlling of the adjustment of the at least one operational parameter of the separator such that the set target value is attained further comprises taking into account the monitored at least one operational parameter of the separator and / or the at least one property of a liquid mixture being supplied to the separator.

[0011] In an embodiment, the method comprises creating a control model based on a plurality of values of said monitored at least one separation process performance parameter and correspondingly adjusted values of said at least one operational parameter, which control model is utilized for controlling the operation of the separator.

[0012] In an embodiment, the method further comprises providing the created control model to a device to which other separators have access, the device being configured to subsequently provide the created control model to the other separators.

[0013] In an embodiment, the method further comprises presenting, to an operator, a plurality of separator operational modes available for selection and receiving, by operator selection, information indicating an order of priority in which the operational modes is to be performed by the separator in response to said user selection, each operational mode prioritizing control of one or more separation process performance parameters of the separator, wherein said at least one operational parameter is controlled to be adjusted to vary within a set allowed range configured to favour an operational mode having higher order of priority.

[0014] In an embodiment, if there is a conflict between one or more separation process performance parameters prioritized by different operational modes, the controlling of the adjustment of at least one operational parameter of the separator affecting the higher prioritized separation process performance should be prioritized such that the corresponding set target value is attained.

[0015] In an embodiment, the method further comprises presenting, to an operator of the separator, said at least one operational parameter being controlled to be adjusted, and the set range in which said at least one operational parameter is allowed to vary.

[0016] In an embodiment, said at least one separation process performance parameter comprises at least one of separator throughput, power consumption, sound level, light phase quality, heavy phase concentration. Further, if e.g. cells are being separated, the viability of the cells being discharged from the separator may be one of said at least one separation process performance parameter.

[0017] In an embodiment, said at least one operational parameter comprises at least one of flowrate of fluid mixture being input to the separator, separator throughput, rotational speed of separator bowl, counter pressure at a light phase outlet or a heavy phase outlet.

[0018] In an embodiment, the set target value of the monitored at least one separation process performance is represented by a target value range. The method may thus comprise controlling adjustment of at least one operational parameter of the separator affecting the monitored at least one separation process performance parameter such that the set target range is attained over time. The target value range may be an interval in which there is stable process conditions for the separation performance parameter.

[0019] In an embodiment, the controlling of the adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained comprises controlling at least two operational parameters of the separator affecting said monitored at least one separation process performance parameter.

[0020] In embodiments, at least two or a plurality of separation process performance parameters are monitored. At least one, or at least two, or a plurality of operational parameters of the separator may thus be adjusted so that the at least two separation process performance parameters are at their set target values or at within their target value ranges over time. Such stable running conditions - i.e. when one or several process performance parameters are mor or less stable over a period of time such as over a period of time that is at least 1 min, such as at least several minutes - may be referred to as a "sweet spot" for the separation process. Since a separation process is a very complex process, the method may in embodiments comprise performing the steps of monitoring, determining and controlling until such a sweet spot is found and later on in the separation process, the steps of monitoring, determining and controlling may be performed until another sweet spot is found.

[0021] In a third aspect, a computer program is provided comprising computer-executable instructions for causing a separator to perform steps recited in the method of the first aspect when the computer-executable instructions are executed on a processing unit included in the separator.

[0022] In a fourth aspect, a computer program product is provided comprising a computer readable medium, the computer readable medium having the computer program according to the third aspect embodied thereon.

[0023] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a cross-sectional view of a prior art centrifugal separator in which embodiments may be implemented; Figure 2 shows a more detailed view of a centrifuge bowl of the centrifugal separator of Figure 1; Figure 3 shows a flowchart illustrating a method of controlling a separator in an embodiment; Figure 4 shows a schematic illustration of a processing unit controlling a separator in an embodiment; Figure 5 shows a flowchart illustrating a method of controlling a separator in another embodiment; Figure 6 shows a schematic illustration of a processing unit controlling a separator in another embodiment; Figure 7 shows a schematic illustration of a separator uploading a created control model to a cloud server for distribution to other separators in an embodiment; Figure 8 illustrates a graphical interface showing an order of priority of selected operational modes of a separator in an embodiment; Figure 9 shows a flowchart illustrating a method of controlling a separator in an embodiment; Figure 10 illustrates a graphical interface showing another order of priority of selected operational modes of a separator in an embodiment; Figure 11 illustrates a graphical interface showing still another order of priority of selected operational modes of a separator in an embodiment; Figure 12 illustrates a graphical interface showing yet another order of priority of selected operational modes of a separator in an embodiment; and Figure 13 illustrates a separator according to an embodiment. DETAILED DESCRIPTION

[0025] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0026] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0027] Figures 1 and 2 illustrates a separator 10 to which a control scheme may be applied in an embodiment. As is understood, the control scheme according to embodiments described herein may be applied to any appropriate separator type, such as such as a clarifier, which is a centrifugal separator for solid - liquid separation, a purifier, which is a centrifugal separator for liquid - liquid - solid separation, and a concentrator, which is a centrifugal separator designed to separate three different phases, one solid phase and two liquid phases of different densities, and clean the densest / heaviest liquid phase.

[0028] Figure 1 shows a cross-section of an embodiment of a centrifugal separator 1 configured to separate a heavy phase and a light phase from a liquid mixture. The centrifugal separator 1 has a rotatable part 4, comprising the centrifuge bowl 5 and drive spindle 4a. As is understood, this is just one example of a separator in which embodiments can be implemented.

[0029] The centrifugal separator 1 is further provided with a drive motor 3. This motor 3 may for example comprise a stationary element and a rotatable element, which rotatable element surrounds and is connected to the spindle 4a such that it transmits driving torque to the spindle 4a and hence to the centrifuge bowl 5 during operation. The drive motor 3 may be an electric motor. Alternatively, the drive motor 3 may be connected to the spindle 4a by transmission means such as a drive belt or the like, and the drive motor may alternatively be connected directly to the spindle 4a.

[0030] The centrifuge bowl 5, shown in more detail in Figure 2, is supported by the spindle 4a, which is rotatably arranged in stationary frame 2 around the vertical axis of rotation (X) in a bottom bearing 22 and a top bearing 21. The stationary frame 2 has an upper hood that surrounds centrifuge bowl 5.

[0031] In the centrifugal separator as shown in Figure 1, liquid mixture to be separated is fed to the bottom to the centrifuge bowl 5 by means of inlet feed pump 25 via the drive spindle 4a. The drive spindle 4a is thus in this embodiment a hollow spindle, through which the feed is supplied to the centrifuge bowl 5. However, in other embodiments, the liquid mixture to be separated is supplied from the top, such as through a stationary inlet pipe extending into the centrifuge bowl 5. The pump 25 may be utilized in order to control flowrate of the fluid mixture being input to the separator 1, which thus affects the separator throughput for the supplied fluid mixture.

[0032] After separation has taken place within the centrifuge bowl 5, separated liquid heavy phase is discharged through stationary outlet pipe 6a, whereas separated liquid light phase is discharged through stationary outlet pipe 7a. Valve 23 may be used to control the counter pressure in stationary outlet pipe 7a and valve 24 may be used to control the counter pressure in stationary outlet pipe outlet pipe 6a. These counter pressures may be used to regulate the radial level of the interface between the liquid heavy phase and the liquid light phase within the centrifuge bowl 4.

[0033] Figure 2 shows a more detailed view of the centrifuge bowl 5 of the centrifugal separator 1.

[0034] The centrifuge bowl 5 forms within itself a separation space 9a and a sludge space 9b, located radially outside the separation space 9a. In the separation space 9a, a stack 10 of separation discs is arranged coaxially around the axis of rotation (X) and axially below a top disc 50. The stack 10 is arranged to rotate together with the centrifuge bowl 5 and provides for an efficient separation of the liquid mixture into at least a liquid light phase and a liquid heavy phase. Thus, in the separation space 9a, the centrifugal separation of the liquid mixture takes place during operation. The sludge space 9b is in this embodiment confined between an inner surface of the centrifuge bowl wall 13 and an axially movable operating slide 16.

[0035] The disc stack 10 is supported at its axially lowermost portion by distributor 11. The distributor is arranged to conduct liquid mixture from the centre inlet 14 of the centrifuge bowl 5 to a predetermined radial level in the separation space 9a.

[0036] The inlet 14 is arranged for receiving the liquid mixture and is designed as a central inlet chamber formed within or under the distributor 11. The inlet 14 communicates with the separation space 9a via passages 17 formed in the distributor 11.

[0037] A number of outlet conduits 30 in the form of channels or pipes are configured to transport separated liquid heavy phase from the sludge space 9b to the second outlet 6. Such liquid heavy phase may comprise some solids as well. In Figure 2, the outlet conduits 30 are formed as pipes having their inlet end portions 31 stretching out in the sludge space 9b to a diameter larger than the disc stack diameter. The outlet conduits 30 have their inlet end portions 31 extending into the sludge space 9b. The outlet conduits 30 extend from a radially outer position of the sludge space 9b to the second outlet 6. The outlet conduits 30 consequently have their inlet end portions 31 arranged at the radially outer position and a conduit outlet 32 arranged at a radially inner position. The outlet conduits are arranged axially above the top disc 50 and in close proximity of the surrounding upper inner wall of the centrifuge bowl 5. Further, the outlet conduits 30 are arranged with an upward tilt relative the radial plane from the inlet end portions 31 to the conduit outlet 32.

[0038] In embodiments, the centrifuge bowl 5 comprises at least four outlet conduits 30. However, the centrifuge bowl 5 may comprises a single outlet conduit. In other embodiments, the centrifuge bowl is free of outlet conduits 30, and separated liquid heavy phase may flow more freely above the top disc 50 to the second outlet chamber 6.

[0039] The radially inner portion of the disc stack 10 communicates with a first outlet 7 for a separated light phase of the liquid mixture. This first outlet 7 of the centrifuge bowl 5 communicates with a stationary outlet pipe 7a for discharging the separated liquid light phase from the centrifuge bowl 5.

[0040] The first and second outlet chambers 6, 7 are mechanically sealed with seals 12a, 12b. As this is an airtight design, the seals are commonly referred to as hermetic seals. The inlet channel 4b is also sealed at lower end of the hollow spindle 4a, thus preventing communication between the inlet channel 4b and the surroundings. This mechanical seal is not shown in the Figures.

[0041] In this example, the centrifuge bowl 5 is further provided with outlets 15 at the radially outer periphery of the sludge space 9b. These outlets 15 are evenly distributed around the rotor axis (X) and are arranged for intermittent discharge of a sludge component of the liquid mixture. The opening of the outlets 15 is controlled by means of an operating slide 16 actuated by operating water channels below the operating slide 16, as is known in the art. In its position shown in the drawing, the operating slide 16 abuts sealingly at its periphery against the upper part of the centrifuge bowl 5, thereby closing the sludge space 9b from connection with outlets 15, which are extending through the centrifuge bowl 5.

[0042] During operation of the separator as shown in Figure 1 and 2, the centrifuge bowl 5 is brought into rotation by the drive motor 3. Via the spindle 4a, liquid mixture to be separated is brought into the separation space 9a, as indicated by arrow "A". Depending on the density, different phases in the liquid mixture is separated between the separation discs of the stack 10. Heavier component, such as a liquid heavy phase and a sludge phase, move radially outwards between the separation discs of the stack 10 to the sludge space 9b, whereas the phase of lowest density, such as a liquid light phase, moves radially inwards between the separation discs of the stack 10 and is forced through the outlet pipe 7a via the first outlet 7, as indicated by arrow "C". The liquid of higher density is instead discharged via the outlet conduits 30 to the second outlet 6 and further out via stationary outlet pipe 6a, as indicated by arrow "B". Solids, or sludge, which accumulate at the periphery of the sludge space 9b and is emptied intermittently from within the centrifuge bowl by the sludge outlets 15 being opened, whereupon sludge is discharged from the separation chamber 15 by means of centrifugal force, as indicated by arrow "D". However, the discharge of sludge may also take place continuously, in which case the sludge outlets 15 take the form of open nozzles and a certain flow of sludge and / or heavy phase is discharged continuously by means of centrifugal force.

[0043] Now, the separator 1 may be configured to control one more specific separation process performance parameters depending on a desired output / performance to be achieved by the separator.

[0044] For instance, in case a particular target value or range of a specific separation process performance parameter of the separator 1, such as e.g. separator throughput, is desired for the fluid mixture being supplied to the separator 1 via the inlet pipe 4a, then an operational parameter of the separator 1 affecting said specific performance parameter (i.e. separator throughput) needs to be carefully controlled. In an example where the separator output parameter to attain a particular target value is embodied in the form of separator throughput, an operational parameter such as e.g. flowrate of the supplied fluid mixture may be controlled by adjusting inlet feed pump 25. Typically, if it is desired that the separator throughput is to attain a high target value, the flowrate of the supplied fluid mixture must typically be controlled to be high, thereby requiring the pump 25 at the inlet channel 4b to be operated at a high speed.

[0045] In another example, a process performance parameter in the form of turbidity is to be controlled to attain a desired target value or range. For instance, if the separated liquid being discharged through the stationary outlet pipe 7a is to be clear and thus have a low turbidity, the separator will typically operate the centrifuge bowl 5 at a high rotational speed to effectively separate the two liquid phases and any solids from each other.

[0046] As is understood, in order to attain separated liquid having a low turbidity, it may further be necessary to reduce the flowrate of the fluid mixture being supplied via the inlet pipe 4a to allow the separator to thoroughly separate the liquid and the solids from the supplied fluid mixture. Hence it may be practically difficult to attain a high separator throughput and a low turbidity for the separated liquid light phase at the same time, i.e. during one and the same operational mode of the separator 1.

[0047] In a further example, sustainability measures in the form of e.g. energy consumption and operating sound level of the separator 1 may be taken into account as process performance parameters, which may be incompatible with both high throughput and low turbidity of the light phase. As is understood, other parameters for determining light phase quality other than light phase turbidity may be envisaged such as the purity of the light phase, or some other parameter related to concentration of the heavy phase or degree of particles in (or visibility / permeability of) the separated light phase.

[0048] Hence, in the above three examples where separation process performance parameters in the form of (a) separator throughput, (b) turbidity of separated liquid and (c) separator energy consumption are to attain desired target levels or ranges, one or more separator operating parameters (e.g. flowrate of the supplied fluid mixture, rotational speed of the bowl 5, etc.) needs to be a carefully controlled. This is challenging and typically managed by an operator of the separator 1 performing appropriate adjustments.

[0049] As can be concluded, there are many challenges to overcome when operating a separator such as the centrifugal separator 1 illustrated with reference to Figures 1 and 2.

[0050] Figure 3 illustrates a flowchart of a method of controlling operation of a centrifugal separator 1 upon the separator performing a separation process according to an embodiment.

[0051] In this exemplifying embodiment, it is assumed that the separation process performance parameter to be controlled is light phase turbidity. Thus, it is desired to attain a liquid light phase which is clear and thus has a low turbidity when exiting via the outlet pipe 7a. On the other hand, it may not be desirable to have a too low turbidity. For instance, assuming that the separator 1 is utilized at a brewery for brewing a product such as beer; it may then be desirable to have a fairly clear light phase liquid (i.e. beer) exiting the outlet pipe 7a while still maintaining some amount of yeast and flavouring agents in the beer.

[0052] In this example, a target value of 50 NTU ("Nephelometric Turbidity Unit") is desired for the separated liquid exiting the separator 1 via the outlet pipe 7a, which is the unit used to measure the turbidity of a fluid (i.e. the presence of suspended particles in the fluid). In other words, the higher the concentration of suspended solids in the fluid is, the cloudier the fluid looks and the higher the turbidity is.

[0053] Further, it may be that a desired target range is set around the target value of 50 NTU, where preferably the light phase turbidity should be in the range of 45-55 NTU.

[0054] It is further assumed that the operational parameter to be controlled for the separator 1 to attain the desired target value for the light phase turbidity is embodied in the form of rotational speed of the bowl 5. Commonly, it may be important that the rotational speed of the bowl 5, as measured in rpm ("rotations per minute"), is allowed to be controlled up to a high value, since a high rotational speed of the bowl 5 generally results in low turbidity of the separated liquid.

[0055] In other words, it may be that a separator operational parameter (e.g. bowl rotational speed) is controlled such that a selected separation process performance parameter (e.g. light phase turbidity) narrowly attains a specific value of, say, 50 NTU, or that a broader range is acceptable, such as 45-55 NTU. Thus, the set target value of the separation process performance parameter may represent a specific value or, which is more common in practice, a range of values; in this embodiment exemplified by the range 45-55 NTU. Thus, a requirement may be that the separation process performance parameter is stable over time within a set range.

[0056] Reference will further be made to Figure 4 illustrating a controller 35 configured to control the separator 1 according to an embodiment. As is understood, this controller 35 may be a stand-alone component arranged remotely from - but in communicative connection with - the separator 1, but may alternatively be embedded in the separator 1 for separator control. In Figure 4, the controller 35 is referred to as a central processing unit (CPU) and may be embodied in the form of one or more microprocessors. As is understood, the communicative connection of the controller 35 with the separator 1 may be wired or wireless.

[0057] As shown in Figure 3, in a first step S101, the CPU 35 monitors one or more separator process performance parameters to be controlled. As mentioned, in this particular example, the CPU 35 is configured to monitor and control the light phase turbidity (LPT), i.e. the turbidity of the separated liquid being output from the separator via the outlet pipe 7a.

[0058] In S102, the CPU 35 determines whether or not the light phase turbidity is within the desired target range of 45-55 NTU. If so, the target range is indeed attained and the rotational speed of the bowl 5 is maintained accordingly in S103. In this particular example, the speed of the bowl 5 is assumed to be maintained at 5000 rpm. In other words, in this embodiment, controlling of at least one operational parameter such that a light phase turbidity is maintained within the desired target range of 45-55 NTU for a certain period of time is considered to constitute a "sweet spot" for the separation process that the separator controlling strives to achieve.

[0059] However, should the CPU 35 determine in S102 that the light phase turbidity is not within the desired target range of 45-55 NTU, such as e.g. at 43 NTU, the CPU 35 will accordingly decrease the rotational speed of the bowl 5 in S104 in order to increase the turbidity of the separated liquid, thus resulting in more particles being present in the separated liquid. The bowl speed is exemplified to be decreased to 4750 rpm, eventually resulting an increase in the light phase turbidity to reach the desired target range of 45-55 NTU.

[0060] In contrast, should the CPU 35 determine in S102 that the currently value of the light phase turbidity is above the desired target range of 45-55 NTU, such as e.g. at 57 NTU, the CPU 35 will accordingly increase the rotational speed of the bowl 5 in S104 in order to decrease the turbidity of the separated liquid, thus resulting in a less amount of particles being present in the separated liquid. The bowl speed is exemplified to be increased to 5250 rpm in order to cause the light phase turbidity to arrive at the desired target range of 45-55 NTU.

[0061] Advantageously, the proposed method enables dynamic and rapid control of the operation of the separator 1 such that a desired target value is attained for one or more monitored separation process performance parameters to be controlled. In this example, the rotational speed of the bowl 5 is controlled such that the light phase turbidity maintains a value in the desired target range of 45-55 NTU for a period of time, thus arriving at stable operating conditions (the above-mentioned separation process "sweet spot").

[0062] Generally, as illustrated in Figure 3, the adjustment of the operational parameter of the separator is continuously performed (i.e. increasing or decreasing the bowl speed) such that the separation process performance parameter is maintained in the set target range (i.e. the light phase turbidity is maintained in the desired target range of 45-55 NTU) over time, which advantageously provides for stable separator operating conditions throughout the separation process.

[0063] In the example described with reference to Figure 3, there may be numerous reasons why the value of the monitored performance parameter of the separator suddenly or gradually changes and eventually deviates from the desired target range. A commonly occurring reason is that a property of the liquid mixture being input to the separator 1 via the inlet 14 changes.

[0064] For instance, if the composition of the liquid mixture being input to the separator 1 via the inlet 14 changes such that a greater amount particles are present in the liquid mixture supplied to the separator 1, the rotational speed of the bowl 5 should generally be increased to maintain the light phase turbidity at the desired target value of around 50 NTU (i.e. in the range of 45-55 NTU). If not, the light phase turbidity of the separated liquid will typically increase with the increasing amount of particles being present in the liquid mixture supplied to the separator 1 via the inlet 14.

[0065] In another example, an operational parameter of the separator may be adjusted, either by the CPU 35 or manually by an operator. For instance, if the inlet feed pump 25 is controlled such that the flowrate of the liquid mixture being supplied to the separator 1 via the inlet 14 increases or decreases, the rotational speed of the bowl 5 should typically be increased or decreased, respectively, to maintain the light phase turbidity at the desired target value of around 50 NTU.

[0066] Thus, the change in the monitored process performance parameter (i.e. the light phase turbidity) is commonly a result of a change in the composition of the liquid mixture or in a change in an operational parameter of the separator 1, such as e.g. a change in the flowrate with which the liquid mixture is supplied to the separator 1 (as adjusted by the inlet feed pump 25). As a result, the selected separator operational parameter may every now and then have to be adjusted such that the desired target value is arrived at for the monitored process performance parameter. However, once the desired target value is arrived at, the operational parameter of the separator 1 is generally maintained at a nominal value (in the above example represented by a bowl speed of 5000 rpm).

[0067] It may further be envisaged that a plurality of operational parameters are adjusted for a monitored process performance parameter to attain a desired target range. For instance, with reference to the examples hereinabove, it may be that the rotational speed of the bowl 5 is adjusted for the light phase turbidity to attain a value in the range of 45-55 NTU. Then, after a while, if for instance the light phase turbidity increases (or decreases), the CPU 35 may choose to decrease (or increase) the flowrate with which the liquid mixture is supplied to the separator 1, rather than adjusting the bowl speed, such that the light phase turbidity again attains a value in the range of 45-55 NTU. As is understood, it may be envisaged that both the rotational speed of the bowl 5 and the flowrate are adjusted more or less simultaneously for having the light phase turbidity attain a value in the range of 45-55 NTU rather than in sequence.

[0068] Moreover, it is envisaged that more than one process performance parameter is monitored. Assuming for instance that the light phase turbidity is monitored to attain a target value range of 45-55 NTU as described hereinabove, it may further be that another process performance parameter is monitored, such as energy consumption of the separator 1. Hence, if e.g. the light phase turbidity needs to be increased, it may be that the flowrate is increased rather than increasing the rotational speed of the bowl 1, if an increase in rotational speed would result in the energy consumption increasing outside of an allowable target energy consumption range. Thus, the method may comprise controlling a plurality of operational parameters such that several process performance parameters are kept within their respective target ranges for a period of time, thus arriving at stable operating conditions (a "sweet spot").

[0069] Figure 5 illustrates a flowchart of a method of controlling operation of a centrifugal separator 1 upon the separator performing a separation process according to a further embodiment.

[0070] Reference will further be made to Figure 6 illustrating the controller 35 configured to control the separator 1 according to the method of Figure 4 in an embodiment.

[0071] As previously described, in first step S101, the CPU 35 monitors the light phase turbidity (LPT), i.e. the turbidity of the separated liquid being output from the separator via the outlet pipe 7a.

[0072] Further, in this embodiment, the CPU 35 determines in S101a a current flowrate with which the liquid mixture is supplied by the inlet feed pump 25 to the separator 1 via the inlet 14. As is understood, the CPU 35 may from the inlet feed pump 25 acquire the current flowrate of the supplied liquid mixture being supplied, which flowrate is adjusted by the inlet feed pump 25.

[0073] In S102, the CPU 35 determines whether or not the light phase turbidity is within the desired target range of 45-55 NTU. If so, the target range is indeed attained and the rotational speed of the bowl 5 is maintained accordingly in S103 at 5000 rpm.

[0074] However, should the CPU 35 determine in S102 that the light phase turbidity is not within the desired target range of 45-55 NTU, such as e.g. at 43 NTU, the CPU 35 will accordingly decrease the rotational speed of the bowl 5 in S104 in order to increase the turbidity of the separated liquid, thus resulting in more particles being present in the separated liquid.

[0075] Additionally, in this embodiment, the CPU 35 will not only take the monitored light phase turbidity into account upon adjusting the currently set bowl speed in S104, but further the currently monitored flowrate of the supplied liquid mixture.

[0076] In this example, it is assumed that if the monitored flowrate (FR) has a first value F1 in one scenario while having a second, higher value F2 in another scenario (for the same light phase turbidity of 43 NTU), then the higher flowrate F2 will result in a slightly lower decrease in bowl speed being performed by the CPU 35 as compared to a scenario where the liquid mixture is supplied with the lower flowrate F1, the rationale being that a higher flowrate F2 eventually will result in a higher light phase turbidity as compared to a lower flowrate F1 for the same bowl speed.

[0077] Thus, given that the light phase turbidity is at 43 NTU, the CPU 35 will in S104 decrease the bowl speed to, say, 4850 rpm for a flowrate of the supplied liquid mixture of F2, while decreasing the bowl speed to 4750 rpm for a flowrate of the supplied liquid mixture of F1. Advantageously, this provides for a more dynamic and accurate control of the separator operational parameters (i.e. bowl rotational speed) in order to attain a desired target value for a monitored separation process performance parameter (i.e. light phase turbidity).

[0078] In an embodiment, machine-learning (ML) and / or artificial intelligence (AI) may be applied by the CPU 35 upon controlling the operation of the separator for creating a control model utilized for controlling operation of the separator 1 performing a separation process. For instance, with reference to the above examples, the CPU 35 may during operation of the separator conclude that the operational parameters should be adjusted according to settings of Table 1, where possibly the CPU 35 may be configured to extrapolate between the monitored values of the desired process performance parameter, thus concluding from the extrapolation that e.g. a light phase turbidity of for instance 45 NTU would result in the rotational bowl speed being adjusted to around 4820 rpm. Table 1. Settings applied during creating of a control model at the CPU.Light phase turbidity (NTU)Set rotational bowl speed (rpm)434750505000575250

[0079] Thus, in this embodiment, the CPU 35 will set up a control model based on the monitored process performance parameters and the corresponding operational parameters, which control model is applied by the CPU 35 when operating the separator 1 in order to advantageously provide dynamic and accurate control of the operation of the separator 1, as described above.

[0080] Further advantageous is that such control model may be shared among other separators such that an already established and tested control model can be applied at numerous other separators.

[0081] Hence, as shown in Figure 7, after the first separator 1a (having the CPU embedded) has created the control model in S201, the first separator 1a uploads the created control model to a remote server 40 (e.g. over the Internet) in S202 to which numerous other separators 1a, 1b, ..., in have access. These other separators 1a, 1b, ..., in may thus in S203 advantageously acquire an already created and accurate control model from the server 40. This is particularly advantageous upon initial configuration of the separators 1a, 1b, ..., 1n. During operation, it may be envisaged that one or more of the separators 1a, 1b, ..., in (such as e.g. second separator 1b) slightly adjusts the control model acquired in S203 to better fit the control process carried out locally at the separator ib. Even so, the control model initially acquired in S203 is of great benefit for the second separator 1b during a configuration phase.

[0082] Figure 8 illustrates an embodiment of a method of controlling operation of the centrifugal separator 1, where a user / operator of the separator 1 is allowed to select from a number of predetermined operational modes which separation process performance parameter(s) to prioritize.

[0083] Now, the separator 1 maybe controlled to operate in different operational modes depending on a desired output to be achieved by the separator, where each mode will favour a specific separation process performance parameter.

[0084] Reference will further be made to Figure 9 showing a flowchart illustrating the method of controlling operation of the centrifugal separator 1 according to the embodiment discussed with reference to Figure 8.

[0085] In this embodiment, a specific operational mode will be performed by the separator 1 depending on certain functionality to be attained during the separation process, where typically the specific operational mode indicates that control of a desired separation process performance parameter is to be favoured before another performance parameter. For instance, in case a low-energy operational mode is performed to favour a low energy consumption of the separator 1, an operational parameter in the form of the rotational speed of the bowl 5 is typically controlled to be low while if a low-turbidity operational mode is performed, the rotational speed of the bowl 5 is typically controlled to be high in order to favour low turbidity of the light phase.

[0086] In an embodiment, the operator may indicate via a user interface, such as a display of the separator or a control device such as a smart phone or a tablet, for which particular application the separator 1 is to be utilized. In this example, the separator is to be used in a brewery application, where for instance sludge in the form of yeast / mash is to be separated from the beer being brewed. Clarified beer is separated as the liquid light phase (C) and yeast is separated and discharged in a liquid heavy phase (B). However, with large volumes of yeast, some may be discharged via the sludge outlets 15 (D).

[0087] Hence, when the user selects the brewery application, the separator 1 will present four operational modes to the operator: "Light phase turbidity", "Heavy phase concentration", "Product flow" and "Energy & Sound" where, as the names imply: (a) the light phase turbidity (LPT) operational mode controls operational parameters of the separator 1 to attain and favour a liquid light phase - i.e. the separated beer - which is clear and thus has a low turbidity when exiting via the outlet pipe 7a, (b) the heavy phase concentration (HPC) operational mode controls operational parameters of the separator 1 to attain a liquid heavy phase (i.e. the separated liquid phase comprising yeast) which has a high concentration and thus is compact upon being discharged via the outlet pipe 6a. (c) the throughput operational mode controls operational parameters of the separator 1 to attain a high throughput for the liquid mixture passing through the separator, and (d) the energy and sound (E&S) operational mode controls operational parameters of the separator 1 to attain a low energy consumption and sound level upon the separator 1 is performing a separation process.

[0088] In other words, the operational modes selected in the above examples will prioritize, and thus favour, the following separation process performance parameters: (a) low light phase turbidity, (b) high heavy phase concentration, (c) high liquid mixture throughput and (d) low energy consumption / sound levels, respectively.

[0089] Thus, in a first step S100a, a plurality of separator operational modes available for selection is presented to the operator, in this example the four different modes (a)-(d) discussed hereinabove.

[0090] When presented with the four different operational modes available for selection for the particular application ("brewery") in S100a, the operator selects in S100b in which order the operational modes are to be prioritized when the separator 1 starts the separation process. For instance, the operator may perform ordering of the operational modes via e.g. a touch-screen display of the separator 1.

[0091] In this particular example, the light phase turbidity mode is given the highest priority, followed by heavy phase concentration mode and the product flow mode, while the energy and sound mode is given the lowest priority, as illustrated in Figure 8.

[0092] In this example, the operator is further allowed to state a desired product flow of 20 m 3< / h with a maximum deviation of ± 5 m 3< / h to be applied by the separator 1 during the performed separation process and a desired turbidity of 50 NTU, with an allowed range for the turbidity of 45-55 NTU, for the separated liquid (i.e. the beer) exiting the separator 1 via the outlet pipe 7a.

[0093] Hence, in S100b the separator 1 receives, by the operator selection, information indicating an order of priority in which the operational modes is to be performed by the separator 1 in response to the selection.

[0094] In response to the information received from the operator indicating the selected priority for the operational modes in S100b, the separator 1 monitors in S101 performance parameters of the separator 1 associated with the operational modes, to ensure that their desired target values are attained upon controlling adjustment in S104 of one or more operational parameters affecting the monitored separation process performance parameters such that the set target values are attained upon the separator 1 performing the prioritized operational mode during the separation process, the highest-priority operational mode in this example being the light phase turbidity operational mode.

[0095] The separation performance parameters monitored in S101 are hence in this exemplifying embodiment (a) light phase turbidity, (b) heavy phase concentration, (c) liquid mixture throughput and (d) energy consumption / sound levels.

[0096] The operational parameters determined to be controlled in S104 to cause performance parameters (a)-(d) to attain their target values are indicated with three meters shown in a right-hand section of Figure 8, namely product flow, rotational speed of the bowl 5 and light phase counter pressure.

[0097] As can be seen in the right-hand section of Figure 8, giving the highest priority to the light phase turbidity operational mode implies that the range of values within which the product flow can be adjusted in S104 during the separation process is fairly broad, from about 16 to 24 m 3< / h. In other words, to maintain a low turbidity for the separated liquid, the separator 1 must be able to decrease the product flow and thus the separator throughput such that the rotation of the rotational bowl 5 causes a thorough separation of the mash / yeast from the liquid mixture supplied to the separator 1 in order to achieve a low turbidity for the separated liquid.

[0098] In this example, since the throughput only is prioritized as the third operational mode after light phase turbidity and heavy phase concentration, the separator 1 has greater degrees of freedom for product flow as an operational parameter to attain a desired turbidity.

[0099] Further, as illustrated in the second meter below the product flow meter indicating rotational speed of the bowl 5, it is important that the rpm ("rotations per minute") of the bowl 5 is allowed to be controlled up to its maximum value of 6250 rpm in the light phase turbidity operational mode, since a high rotational speed of the bowl 5 generally results in low turbidity of the separated liquid.

[0100] Moreover, as shown in the third meter indicating light phase counter pressure, which controls the counter pressure on the liquid light phase outlet; similar to the product flow, this is allowed to be controlled in a relatively broad range of values ranging from 1 to 8.5 bar, which while not being particularly important for the light phase turbidity operational mode indeed is required to attain a heavy phase concentration being the second-highest prioritized operational mode.

[0101] A high light phase counter pressure provides for achieving a high concentration of the heavy phase, if needed. For example, a high rotational speed of the bowl in combination with a low product flow may result in a high concentration of the heavy phase within the bowl, and a high light phase counter pressure may then aid in discharging such highly concentrated heavy phase.

[0102] As further can be concluded from Figure 8, both the product flow and the rotational speed of the bowl 5 is allowed to be controlled up to high parameter values, which generally is not beneficial for energy consumption and sound level, which is in line with the energy and sound operational mode being least prioritized in this example.

[0103] Thus, if in a scenario where e.g. performance parameter (c) ("throughput") cannot be controlled to reach its target value without also performance parameter (a) ("light phase turbidity") failing to reach its target value, control of the light phase turbidity will be prioritized in S104. In other words, it may be that the process is controlled such that the light phase turbidity reaches its target value while the throughput will not.

[0104] Figure 10 illustrates a further embodiment, where the operator in S100b indicates a different order of priority in which the operational modes is to be performed by the separator 1.

[0105] In this particular example, throughput mode is given the highest priority, followed by the energy and sound mode and the light phase turbidity mode, while the heavy phase concentration mode is given the lowest priority.

[0106] In this example, the operational parameters to be controlled in S104 are the same as in the previous example, albeit with differently assigned ranges. As is understood, the examples described herein are for brevity illustrated to control (the same) three parameters while in a practical scenario, tens of operational parameters may be controlled and different operational parameter may be controlled for differently prioritized operational modes.

[0107] As can be seen in the right-hand section of Figure 10, giving the highest priority to the product flow operational mode implies that the range of values that can be controlled in S104 for the product flow will be set relatively narrow from about 19 to 21 m 3< / h, giving an accurate and well-predictable range for the product flow, which is desired by the operator when the throughput mode is given the highest priority.

[0108] Further, as illustrated in the second meter below the product flow meter indicating rotational speed of the bowl 5, the rotation speed of the bowl 5 is kept fairly low in the range 4000-4750 rpm, which is in compliance with the second-highest prioritized energy mode and the third-highest mode being the light phase turbidity mode. In other words, a low rotational speed will result in a low energy consumption and a relatively silent separator operation. Further, since the light phase turbidity mode has a low priority, it is not necessary for the separator 1 to rotate the bowl 5 at a high rpm.

[0109] The third meter indicating a low light phase counter pressure will further be beneficial for low energy consumption, and since the heavy phase concentration is the least prioritized operational mode of the four modes, it is not necessary for the separator 1 to be able to provide a high light phase counter pressure.

[0110] Hence, as can be concluded, with the differently set ranges for the operational parameters, the new prioritization of Figure 10 (as compared to that of Figure 8) will advantageously be favoured by the separator and the characteristics associated with the throughput mode will be provided with the separator control, such as e.g. an accurate and predictable product flow range.

[0111] Figure 11 illustrates still a further embodiment, where the operator in S100b indicates still a different order of priority in which the operational modes is to be performed by the separator 1.

[0112] In this particular example, light phase turbidity mode is given the highest priority, followed by the energy and sound mode and the throughput mode, while the heavy phase concentration mode again is given the lowest priority.

[0113] As can be seen in the right-hand section of Figure 11, giving the highest priority to the light phase turbidity operational mode implies (as in Figure 8) that the range of values that can be controlled in S104 for the product flow is fairly broad, from about 16 to 24 m 3< / h. In other words, as in the example of Figure 8, to maintain a low turbidity for the separated liquid, the separator 1 must be able to decrease the product flow and thus the separator throughput such that the rotation of the rotational bowl 5 causes a thorough separation of the mash / yeast from the liquid mixture supplied to the separator 1 in order to achieve a low turbidity for the separated liquid.

[0114] However, in contrast to the operational parameter settings of Figure 8, since the energy and sound mode in this example is the second-highest prioritized mode, the rotational speed of the bowl 5 is allowed to increase to a value of 5500 rpm, rather than to 6250 rpm as was the case in Figure 8.

[0115] Further, since the heavy phase concentration mode is the least prioritized mode, the light phase counter pressure is kept low at 1-2.5 bar, which is further beneficial for the energy and sound mode.

[0116] Figure 12 illustrates a fourth exemplifying embodiment, where the operator in S100b indicates yet a different order of priority in which the operational modes is to be performed by the separator 1.

[0117] In this particular example, heavy phase concentration mode is given the highest priority, followed by the throughput mode and the light phase turbidity mode, while the energy and sound mode is given the lowest priority.

[0118] As can be seen in the right-hand section of Figure 12, giving the highest priority to the heavy phase concentration operational mode and the second-highest priority to the throughput mode indicates that the product flow will be set relatively narrow from about 18 to 22 m 3< / h, giving a relatively accurate and well-predictable range for the product flow, which is desired by the operator when the throughput mode is given the second highest priority. However, as compared Figure 10 where the throughput mode was given the highest priority, the set range of the product flow is somewhat wider (i.e. 18-22 m 3< / h rather than 19-21 m3 / h), since a more varying product flow typically is required for attaining high heavy phase concentration, being the highest-priority mode.

[0119] Further, while the range of the rotational speed of the bowl 11 is the same as that being set in Figure 11, the range of the light phase counter pressure must be greatly widened. In this example, the range of the light phase counter pressure is set to 1-10 bar, which may be necessary in order to be able to discharge a high heavy phase concentration at different conditions and applications.

[0120] It should be understood that the ranges for the values of the operational parameters illustrated in the three meters in the right-hand part of Figure 8 and 10-12 not necessarily are displayed to the operator but may be set and kept internally in the separator 1.

[0121] Figure 13 illustrates a separator 1 according to an embodiment, where the steps of the method of controlling operation of the separator upon the separator performing a separation process in practice are performed by previously mentioned processing unit 35 with which the separator 1 is equipped, the processing unit 35 being embodied in the form of one or more microprocessors arranged to execute a computer program 36 downloaded to a storage medium 37 associated with the microprocessor, such as a Random Access Memory (RAM), a Flash memory or a hard disk drive. The processing unit 35 is arranged to cause the separator 1 to carry out the method according to embodiments when the appropriate computer program 36 comprising computer-executable instructions is downloaded to the storage medium 37 and executed by the processing unit 35. The storage medium 37 may also be a computer program product comprising the computer program 36. Alternatively, the computer program 36 may be transferred to the storage medium 37 by means of a suitable computer program product, such as a Digital Versatile Disc (DVD) or a memory stick. As a further alternative, the computer program 36 may be downloaded to the storage medium 37 over a network. The processing unit 35 may alternatively be embodied in the form of a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), etc. The separator 1 may further comprise a communication interface 38 (wired and / or wireless) over which the separator 1 is configured to transmit and receive data.

[0122] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

[0123] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Examples

Embodiment Construction

[0025]The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0026]These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0027]Figures 1 and 2 illustrates a separator 10 to which a control scheme may be applied in an embodiment. As is understood, the control scheme according to embodiments described herein may be applied to any appropriate separator type, such as such as a clarifier, which is a centrifugal separator for solid - liquid separation, a purifier, which is a centrifugal separator for liquid - liquid - solid separation, and a concentrator,...

Claims

1. A method of controlling operation of a centrifugal separator (1) upon the separator performing a separation process, comprising: monitoring (S101) at least one separation process performance parameter of the separator (1): determining (S102) whether or not a value of said monitored at least one separation process performance parameter attains a set target value; and if not controlling (S104) adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

2. The method of claim 1, wherein the adjustment of said of at least one operational parameter of the separator continuously is performed such that said at least one separation process performance parameter is maintained at the set target value over time.

3. The method of claims 1 or 2, wherein upon determining (S102) that the value of said monitored at least one separation process performance parameter attains the set target value, the method comprises: maintaining (S103) the value of said at least one operational parameter of the separator at its current value.

4. The method of any one of the preceding claims, further comprising: monitoring (S101a) at least one operational parameter of the separator (1) and / or at least one property of a liquid mixture being supplied to the separator (1), wherein the controlling (S104) of the adjustment of the at least one operational parameter of the separator such that the set target value is attained further comprises taking into account the monitored at least one operational parameter of the separator (1) and / or the at least one property of a liquid mixture being supplied to the separator (1).

5. The method of any one of the preceding claims, further comprising: creating (S201) a control model based on a plurality of values of said monitored at least one separation process performance parameter and correspondingly adjusted values of said at least one operational parameter, which control model is utilized for controlling the operation of the separator (1).

6. The method of claim 5, further comprising: providing (S202) the created control model to a device (40) to which other separators (1b, 1c, ..., 1n) have access, the device (40) being configured to subsequently provide the created control model to the other separators (1b, 1c, ..., 1n).

7. The method of any one of the preceding claims, further comprising: presenting (S100a), to an operator, a plurality of separator operational modes available for selection; and receiving (S100b), by operator selection, information indicating an order of priority in which the operational modes is to be performed by the separator in response to said user selection, each operational mode prioritizing control (S104) of one or more separation process performance parameters of the separator (1), wherein said at least one operational parameter is controlled (S104) to be adjusted to vary within a set allowed range configured to favour an operational mode having higher order of priority.

8. The method of claim 7, wherein if there is a conflict between one or more separation process performance parameters prioritized by different operational modes, the controlling (S104) of the adjustment of at least one operational parameter of the separator affecting the higher prioritized separation process performance should be prioritized such that the corresponding set target value is attained.

9. The method of any one of the preceding claims, further comprising: presenting, to an operator of the separator (1), said at least one operational parameter being controlled (S104) to be adjusted, and the set range in which said at least one operational parameter is allowed to vary.

10. The method of any one of the preceding claims, said at least one separation process performance parameter comprising at least one of separator throughput, power consumption, sound level, light phase quality, heavy phase concentration.

11. The method of any one of the preceding claims, said at least one operational parameter comprising at least one of flowrate of fluid mixture being input to the separator (1), separator throughput, rotational speed of separator bowl (5), counter pressure at a light phase outlet or a heavy phase outlet.

12. The method of any one of the preceding claims, wherein the set target value of the monitored at least one separation process performance is represented by a target value range.

13. The method of any one of the preceding claims, wherein the controlling (S104) of the adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained comprises controlling at least two operational parameters of the separator affecting said monitored at least one separation process performance parameter.

14. A computer program (36) comprising computer-executable instructions for causing a separator (1) to perform steps recited in any one of claims 1-13 when the computer-executable instructions are executed on a processing unit (35) included in the separator (1).

15. A computer program product comprising a computer readable medium (37), the computer readable medium having the computer program (36) according to claim 14 embodied thereon.

16. A centrifugal separator (1) configured to perform a separation process, comprising a processing unit (35) being configured to control the centrifugal separator (1) to be operative to: monitor (S101) at least one separation process performance parameter of the separator (1): determine (S102) whether or not a value of said monitored at least one separation process performance parameter attains a set target value; and if not to control (S104) adjustment of at least one operational parameter of the separator affecting said monitored at least one separation process performance parameter such that the set target value is attained.

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