Centrifugal separator, method for operating a centrifuge, and computer-readable media

Abstract

The present invention relates to a centrifuge 19, in particular a continuous centrifuge, a centrifuge for biotechnology or a centrifuge for blood. The centrifuge 19 has a refrigerant circuit 1. According to the present invention, the output side of the controllable compressor 4 is coupled to the input side of the evaporator 2 via this bypass pipe 15 having a valve 20 arranged in the bypass pipe 15. In the normal operation mode, when the valve 20 is closed, the centrifuge bowl 3 is cooled only by the control of the compressor 4 and the expansion device 6. On the other hand, when the temperature in the centrifuge bowl 3 falls below the allowable range of the set temperature in the centrifuge bowl 3, the valve 20 is opened in order to return the temperature in the centrifuge bowl 3 within the allowable range.

Description

Technical Field

[0001] The present invention relates to a centrifuge.

Background Art

[0002] The centrifuge is preferably a continuous centrifuge. In the case of this continuous centrifuge, at least one medium is supplied to and / or discharged from the centrifuge chamber at least temporarily while the centrifuge chamber is rotating. The at least one medium is, in particular, a medium to be centrifuged, a cleaning liquid, a buffer solution, or a corrected medium extracted from the centrifuged medium or a precipitate in the centrifuge chamber. To list only a few examples that do not limit the present invention, the continuous centrifuge can be a centrifuge for blood in which the medium to be centrifuged is blood and the corrected medium or precipitate to be extracted is blood cells or blood particles, or a centrifuge in which particles contained in cells, microcarriers or other media are obtained from the medium. The centrifuged medium can also be a solution or suspension containing particles such as cells, cell debris or cell fragments, rather than a pure liquid. Such a continuous centrifuge is used, for example, in biopharmaceutical companies or bioprocessing equipment for manufacturing biopharmaceutical or biotechnology products. In this case, the continuous centrifuge is used, for example, to recover and / or purify cells or microcarriers. In this case, the cells thus obtained can be used for cell therapy. Other application fields are, but not limited to, the production of vaccines or the treatment of blood to obtain blood cells. Such continuous centrifuges are sold, for example, under the designation "Ksep®" by Sartorius AG (Otto-Brenner-Strasse 20, 37079 Goettingen, Deutschland) and related companies. See also www.sartorius.com / en / products / process-filtration / cell-harvesting / ksep-systems (date of viewing: June 28, 2022).

[0003] The rotor of such a continuous centrifuge may be formed as a bag held within the rotor body and have four centrifugation chambers evenly distributed around it. In this case, these centrifugation chambers are arranged radially, spaced apart from the rotor's axis of rotation. A first connecting pipe leads to the centrifugation chambers radially from the inside, while a second connecting pipe leads to these centrifugation chambers radially from the outside. In the first operating phase, a first medium, configured as, for example, blood, is supplied to the centrifugation chambers via the second connecting pipe, while the centrifugation chambers rotate with the rotor. Within the centrifugation chambers, as a result of centrifugation, particles contained in the medium settle radially outward, while residual medium is discharged from the centrifugation chambers via the first connecting pipe (the amount of medium supplied radially from the outside is reduced by the amount of particles pushed radially outward). Thus, in this first operating phase, the first connecting pipe is the discharge pipe, while the second connecting pipe is the supply pipe. As this operation continues, the proportion and concentration of particles within the centrifugation chambers increase until the chambers are almost or completely filled with particles. In the subsequent optional second operating phase, the particles in the centrifuge chamber are washed. For this purpose, a washing solution or buffer solution is sent to the centrifuge chamber via a second connecting pipe. The washing solution or buffer solution passes through the centrifuge chamber and is discharged radially from the inside via the first connecting pipe. In this operating phase as well, the centrifuge chamber rotates with the rotor so that, as a result of the acting centrifugal force, particles are prevented from flowing out of the centrifuge chamber through the first connecting pipe along with the washing solution or buffer solution. During this second operating phase, the first connecting pipe is used as a discharge pipe for the washing solution or buffer solution, while the first connecting pipe is used as a supply pipe for the washing solution or buffer solution. In the subsequent third operating phase, the centrifuge chamber continues to rotate with the rotor. In this third operating phase, the direction of flow into the centrifuge chamber is reversed, with particles being removed from the centrifuge chamber via the second connecting pipe, while the washing solution or buffer solution is supplied to the centrifuge chamber via the first connecting pipe. The third operating phase ends when all particles have been removed from the centrifuge chamber.Subsequently, further cycles are executed sequentially through the three operating phases described.

[0004] Such continuous centrifuges that can be used in the present invention are known, for example, from European Patent No. 3936601, European Patent No. 2310486, European Patent No. 2485846, U.S. Patent No. 4,216,770, U.S. Patent No. 4,419,089, U.S. Patent No. 4,389,206 and U.S. Patent No. 5,665,048.

[0005] A centrifuge according to the present invention may have a horizontal rotating shaft. In this case, the medium (e.g., blood, washing solution, and particles) can be exchanged within the region of the rotating rotor shaft during centrifugation. A continuous centrifuge configured in this way may be, for example, a blood centrifuge in which blood is used as the medium.

[0006] Furthermore, the present invention relates to a method for operating such a centrifuge and a computer-readable medium.

[0007] European Patent No. 2814617 discloses the following information relating to the prior art for cooling laboratory centrifuges:

[0008] During centrifugation, especially in laboratory centrifuges rotating at very high speeds, heat due to air friction and power loss is generated within the centrifuge bowl while the rotor rotates. Since the centrifuge bowl is sealed by a lid to prevent the centrifugal material from flowing out, this heat dissipation is not easily achieved, and the temperature of the centrifugal material rises. However, this temperature rise is undesirable because it can destroy or render the centrifuged sample unusable. Generally, the sample must be maintained at a predetermined temperature, for example, 4°C, 22°C, or 37°C depending on the application. Therefore, measures have traditionally been taken to avoid the temperature rise of the centrifugal material. In this case, indirect cooling is frequently used. In this indirect cooling, the rotor is sealed under the centrifuge lid within the centrifuge bowl, and no cooling channels are provided. Therefore, air circulates only within the centrifuge bowl. In this case, cooling is achieved by a second medium induced along the outer surface of the bowl or induced into the bowl. For this reason, a refrigerant circuit with a compressor, piping, and heat exchanger is often provided. To remove heat, a special refrigerant is guided along the centrifuge bowl, for example, via a refrigerant circuit, through piping that spirally contacts the side walls and floor of the bowl. Unlike the "refrigerant" used, for example, in the cooling water circuits of automobiles, the refrigerant undergoes a phase change, i.e., changes from liquid to gas, as it flows through the refrigerant circuit. Temperature control of objects to be cooled below ambient temperature is also possible with such a refrigerant. Cooling a sample article to below ambient air temperature is also possible with a refrigerant circuit. Such laboratory centrifuges are known, for example, from German Patent Application Publication No. 3818584 and Japanese Patent Publication No. 2011-255330. Such a refrigerant circuit 1 has an evaporator 2, a compressor 4, a condenser 5, and an expansion device 6 arranged annularly around the centrifuge bowl 3 (see Figure 1). In this case, the expansion device 6 is designed to correspond to the maximum load condition, i.e., the maximum rotational speed of the centrifuge rotor (not shown). In this case, the expansion device 6 (a pressure adjustment element between the high-pressure and low-pressure sides of the refrigerant circuit 1 when the compressor 4 is stopped) is configured as a capillary tube or a thermostatic injection valve 7 (abbreviated as "TEV").In cooperation with a pressure-controlled temperature detection unit 8 located behind the evaporator 2, the thermostatic injection valve 7 is used to increase or decrease the refrigerant flow rate in the refrigerant circuit 1 depending on the temperature detected at the input VE of the evaporator. To increase or decrease the refrigerant flow rate, the refrigerant at the output VA of the evaporator must be overheated so that an overpressure directly applied to the spring 9 of the thermostatic injection valve 7 is generated to control the thermostatic injection valve 7. More precisely, the output VA of the evaporator reaches a specific temperature. The sensor 10 of the thermostatic injection valve 7 is fixed to the output VA of the evaporator. Similarly, the thermostatic injection valve 7 contains refrigerant that may correspond to the refrigerant in the refrigerant circuit 1. Due to the temperature at the output VA of the evaporator, the refrigerant acts on the repulsive force between the thermostatic injection valve 7 and the spring 9, and therefore has the appropriate pressure to open and close the thermostatic injection valve 7. Here, some of the other load conditions can be controlled, often imprecisely, by another control unit, which is a frequency-controlled or rotational speed-controlled compressor 4. The evaporator's performance cannot be fully utilized because refrigerant overheating is necessary for the thermostatic injection valve 7 to function. In this case, only about 95% of the evaporator's surface area can be utilized. For this overheating to occur, the temperature difference between the evaporator's input VE and output VA needs to be about 7K. Another significant drawback of such known refrigerant circuits 1 in centrifugal separators is that the compressor 4 can only be controlled relatively imprecisely and only within a specific output range. As a result, depending on different partial load conditions or low load conditions, it may be necessary to completely shut down the compressor 4. However, this is not always possible because the compressor 4 generally has a minimum operating time to ensure internal oil circulation. Conversely, if the drive motor of the compressor 4 overheats during startup and necessary pressure adjustment, or if the pressure difference between the high-pressure and low-pressure sides decreases, such a compressor 4 will shut down for a specific minimum period. Therefore, the control performance of the compressor 4 is severely limited, especially in the low power range. Another drawback is that vibration occurs when the compressor 4 of the refrigerant circuit 1 starts or stops.This vibration affects the operating behavior of the centrifuge, increasing the reverse mixing ratio in the rotor after the centrifuge stops, and affecting adjacent experimental equipment. Ultimately, the lifespan of the compressor 4 is shortened due to its frequent on / off cycles.

[0009] Based on this, European Patent No. 2814617 proposes a refrigerant circuit 1 in which the expansion device 6 is configured as an electronically controllable throttle, either continuously or discontinuously (and may also be configured as an electronic injection valve 11) (see Figure 2). Temperature sensors 12, 13, and 14 detect the temperature of the refrigerant at the input VE of the centrifugal separator bowl 3, the actual temperature inside the centrifugal separator bowl 3, and the temperature at the output VA of the centrifugal separator bowl 3. The temperature signals from the temperature sensors 12, 13, and 14, the set temperature of the centrifugal separator bowl 3, and the allowable range (particularly ±5K) of the actual temperature of the centrifugal separator bowl 3 relative to the set temperature are supplied to the electronic control unit. The electronic control unit operates the electronic injection valve 11 and a controllable compressor 4 for temperature control. Bypass piping 15 connects the connecting piping 16 between the electronic injection valve 11 and the evaporator 2 to the connecting piping 17 between the output of the compressor 4 and the evaporator 2. An electronic injection valve 18 is located in the bypass piping 15. The electronic control unit can also control the electronic injection valve 18. According to European Patent No. 2814617, coarse and fine adjustments can be switched as needed, as follows: Coarse adjustment is performed at the start of the laboratory centrifuge until the actual temperature is within an acceptable range for a preset period. After that, a switch is made, and fine adjustment is essentially maintained during further operation. Coarse adjustment is performed again only when, despite the fine adjustment, the actual temperature falls outside the acceptable range. During coarse adjustment, only the compressor 4 is controlled without the control of the electronic injection valves 11, 18. In contrast, during fine adjustment, the output of the compressor 4 is not changed. In this case, control is performed by controlling the electronic injection valve 11. In this case, during the fine adjustment, the electronic injection valve 11 is controlled based on three different criteria. First, if the actual temperature of the centrifuge bowl 3 tends to decrease (or increase) within a preset trend period, the electronic injection valve 11 is controlled downward (or upward). This reduces (or increases) the flow rate of the refrigerant. The opening of the electronic injection valve 11 is controlled even when the temperature of the refrigerant at the input VE of the evaporator 2 is lower than a preset threshold for temperature at the input VE of the evaporator 2. In this case, the opening is maintained until the temperature rises again above the preset threshold.In this way, the compressor 4 is prevented from operating in a vacuum. Finally, the difference between the temperature at the compressor output VA and the temperature at the compressor input VE is also monitored. This difference must be between 0K and 1K in order to maintain the evaporator 2's operating rate to the maximum and prevent liquid refrigerant from reaching the compressor 4. If the difference falls below the specified value, the electronic injection valve 11 is further closed and / or the compressor frequency is reduced.

[0010] Japanese Patent Publication No. 2010-008022 discloses a refrigerant circuit for a centrifugal separator. In this centrifugal separator, in normal operating mode, without control options, the refrigerant flows from the compressor to the evaporator via two capillary tubes arranged in series with the condenser and dryer. If the temperature of the cooled centrifugal separator bowl becomes too low as a result, a bypass valve is moved to the open position. As a result, the refrigerant may also flow from the compressor output to the evaporator via a bypass pipe and a capillary tube located downstream. In this case, the refrigerant flowing through the bypass pipe bypasses the condenser and the capillary tube located upstream. To set the flow rate of the refrigerant in the parallel piping branch when the solenoid valve is open, the inner shape of the upstream capillary tube is selected to be smaller than the inner shape of the downstream capillary tube.

[0011] European Patent Application Publication No. 0295377 discloses a refrigerant circuit for a centrifugal separator. In this centrifugal separator, the output of the compressor is connected to the cooling coil of the centrifugal separator bowl via a parallel circuit of a high-temperature piping line and a low-temperature piping line (in which the condenser is located). Pulse width modulation valves are located in both the high-temperature and low-temperature piping lines. In this case, these valves are operated alternately. In this case, the heat supplied to the cooling coil depends on a pulse width controlled based on the measured temperature in the centrifugal separator bowl. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] European Patent No. 3936601 [Patent Document 2] European Patent No. 2310486 [Patent Document 3] European Patent No. 2485846 [Patent Document 4] U.S. Patent No. 4,216,770 [Patent Document 5] U.S. Patent No. 4,419,089 [Patent Document 6] U.S. Patent No. 4,389,206 [Patent Document 7] U.S. Patent No. 5,665,048 [Patent Document 8] European Patent No. 2814617 [Patent Document 9] German Patent Application Publication No. 3818584 [Patent Document 10] Japanese Patent Publication No. 2011-255330 [Patent Document 11] Japanese Patent Publication No. 2010-008022 [Patent Document 12] European Patent Application Publication No. 0295377 Specification [Patent Document 13] European Patent Application Publication No. 3560592 [Overview of the project] [Problems that the invention aims to solve]

[0013] The object of the present invention is to improve the response performance to an undesirable temperature drop in the centrifugal separator bowl in the configuration of a centrifugal separator and a method for operating a centrifugal separator. Furthermore, the present invention is to provide a computer-readable medium having a control logic unit for a appropriately improved method. [Means for solving the problem]

[0014] According to the present invention, the problems of the present invention are solved by the features described in the independent claims. Other preferred configurations of the present invention are described in the dependent claims.

[0015] The present invention relates to a centrifuge having a centrifuge bowl. Furthermore, the centrifuge particularly has a refrigerant circuit in which a refrigerant that undergoes a phase change within the centrifuge bowl circulates. The refrigerant circuit is used to cool the centrifuge bowl in order to guarantee a set temperature within an allowable range within the centrifuge bowl.

[0016] In the centrifuge, the temperature within the centrifuge bowl is detected (directly or indirectly) by a temperature sensor. To give some examples that do not limit the invention, the temperature sensor can be arranged on the wall of the centrifuge bowl or on the lid of the centrifuge, and in particular can be arranged as closely as possible to the centrifugation chamber of the centrifuge bowl or can be directly adjacent to this centrifugation chamber. However, it is also possible for the temperature sensor to be incorporated in the rotor or in a centrifuge container for the centrifugate held by the rotor (see also European Patent Application Publication No. 3560592).

[0017] The refrigerant circuit used within the scope of the present invention has a compressor whose rotational speed, frequency and / or output can be controlled. Furthermore, the refrigerant circuit has a condenser, particularly a capacitor. Furthermore, an adjustable expansion device is arranged in the refrigerant circuit. The refrigerant circuit also has an evaporator that cools the centrifuge bowl. Thus, for example, the evaporator can surround the centrifuge bowl by piping or the piping can be incorporated into the side wall of the centrifuge bowl. In the refrigerant circuit, the adjustable expansion device is particularly arranged upstream of the evaporator. The control of the refrigerant flow rate and / or the expansion of the refrigerant, that is, the state of the pressure behavior and temperature behavior of the refrigerant in the low-pressure side and in the region of the evaporator, can be influenced by the adjustable expansion device. In this case, the adjustable expansion device can be configured passively, particularly as a thermostat-type injection valve, or can be configured actively, particularly as an electronically controlled throttle or other electronically controlled expansion device.

[0018] According to the present invention, a connecting pipe connecting a compressor to a condenser is connected to a connecting pipe between an expansion device and an evaporator via a bypass pipe. Preferably, the bypass pipe bypasses the condenser and an adjustable expansion device. In this case, the bypass pipe connects between the high-pressure side and the low-pressure side of the refrigerant circuit. To control the connection, an electronically controlled valve for controlling the flow rate flowing through the bypass pipe is arranged in the bypass pipe.

[0019] The present invention proposes that a centrifugal separator is provided with an electronic control device having a control logic unit. The control logic unit monitors the difference between a preset temperature in the centrifugal separator bowl and the temperature detected by a temperature sensor, that is, the actual temperature in the centrifugal separator bowl. When this difference is greater than a preset threshold value, the valve arranged in the bypass pipe is operated by the control device so that the flow rate flowing through this bypass pipe is increased. Preferably, when the compressor has already been set to the minimum output by the control device and / or when the expansion device is operated by the control device so that heat is maximally absorbed by the evaporator, the increase in the flow rate is executed. Therefore, the conventional means for avoiding a decrease in the temperature in the centrifugal separator bowl have already been exhausted, and nevertheless, when the set temperature is below the threshold value, preferably, the valve is controlled to increase the flow rate flowing through the bypass pipe (without the means of the present invention, it may be necessary to stop the compressor in some cases). In this case, by the control of the valve, more refrigerant flows from the high-pressure side to the low-pressure side and reaches the input part of the evaporator. Therefore, the amount of the higher-temperature refrigerant on the high-pressure side mixed into the low-pressure side of the input part of the evaporator increases. As a result, finally, the amount of heat released from the evaporator to the centrifugal separator bowl can be reduced. Thus, an excessive decrease in the temperature in the centrifugal separator bowl can be avoided. This can be realized without the need to stop the compressor or without the need to significantly reduce the output of the compressor.

[0020] In principle, there are a variety of options regarding the type of valve to be placed in the bypass piping (e.g., poppet valve, slide valve, etc.), its operating position (continuous operating position, any number of discrete operating positions), and possible operations, as long as they can be controlled by an electronic control device. Any valve known from the prior art and suitable for this purpose can be used. In this invention, it is proposed that the valve is configured as a two-way solenoid valve having a larger open position and a smaller open position. For example, the smaller open position can be the shut-off position and the larger open position can be the flow position. In this case, the valve is essentially in the shut-off position, where the bypass piping is closed. The two-way solenoid valve is controlled from the controlled position to the flow position only when the difference between the set temperature in the centrifuge bowl and the temperature detected by the temperature sensor is greater than a threshold. In this case, the two-way solenoid valve takes its shut-off position without electrical excitation by the control device, while electrical excitation is possible to switch it to the flow position. However, it is also possible to design the valve in reverse so that it moves to the shut-off position by electrical excitation. In this case, a stable position of the valve, which can be released solely by electrical excitation, can be held by a spring. In another embodiment, the valve may be configured as a visible valve that holds a set flow-through position and an off-peak position without requiring the valve to be electrically excited. Electrical excitation of the valve is required only to switch the valve position in both directions.

[0021] There are various options for the criteria for controlling a two-way solenoid valve to the flow position. For example, the two-way solenoid valve can be controlled to the flow position until the difference between the set temperature in the centrifuge bowl and the temperature detected by the temperature sensor falls below a threshold or any other temperature correlated with the set temperature. In a very simple configuration of the present invention, the control logic unit controls the two-way solenoid valve from the shut-off position to the flow position for a predetermined period. In this case, to give some examples that do not limit the present invention, the predetermined period may depend on centrifuge operating parameters that may relate to the rotational speed of the centrifuge, the ambient temperature of the centrifuge, the actual centrifugal material, and / or the type of rotor used in the centrifuge. It is also possible that the period for which the valve is controlled to the flow position by the control logic unit is learned during the operation of the centrifuge, possibly over a number of operating cycles.

[0022] Within the scope of the present invention, any expansion device may be used, including an electronically controlled expansion valve or an electronically controlled throttle. In a very simple configuration of the present invention, a passive thermostat-type injection valve is used as the injection device within the scope of the present invention.

[0023] Any type of compressor can be used in the centrifugal separator of the present invention. Preferably, a rotary piston compressor is used. The operation of this rotary piston compressor has been demonstrated to be very beneficial on the one hand for preventing unwanted vibrations, and on the other hand, it may also be beneficial for the operation of environmentally friendly refrigerants.

[0024] In the solution of the present invention, instead of configuring the valve as a two-way solenoid valve, a valve having multiple different opening cross-sections may be used. In this case, the valve has multiple discrete operating positions correlated with the different opening cross-sections. Similarly, the valve can have a series of different opening cross-sections. In this case, the different opening cross-sections may or may not have a fully closed position and / or a fully open position. For example, the valve may be configured as a proportional control valve that allows for a series of different opening cross-sections in response to electrical excitation. The valve may also provide multiple different opening cross-sections, in which the valve is configured as a pulse width modulation valve. In the case of such a pulse width modulation valve, the duty cycle for pulse width modulation correlates with the opening cross-section. In such a configuration, the control device has a control logic unit. This control logic unit widens the opening cross-section when the difference between the set temperature in the centrifuge and the temperature detected by the temperature sensor is greater than a threshold. However, in this case, the widening of the opening cross-section depends on the absolute value of the difference, the rate of change of the difference, and / or the period during which the difference is greater than the threshold. For example, initially, the opening of the valve may be widened only slightly. If the control logic unit of the control device confirms that the temperature inside the centrifuge bowl is still very low, the opening is further enlarged. Within the scope of the present invention, open-loop control of the opening cross-section or closed-loop control of the size of the opening cross-section may be performed based on the operating parameters of the centrifuge, in particular the actual temperature inside the centrifuge bowl.

[0025] According to the present invention, the control logic unit of the control device operates in two modes: The normal operating mode is available when the difference between the set temperature in the centrifuge bowl and the temperature detected by the temperature sensor is less than a threshold (or secondary threshold). In normal operating mode, the control logic unit performs open-loop or closed-loop control using only the adjustable expansion device and / or the controllable compressor. In normal operating mode, the valve is in the first position.

[0026] The abnormal operation mode can be used when the difference between the set temperature in the centrifugal separator bowl and the temperature detected by the temperature sensor is greater than a threshold (or the second threshold mentioned above). In the abnormal operation mode, the control logic unit controls the valve to a second position different from the first position. In this case, according to the present invention, no additional open-loop or closed-loop control by the compressor is performed in the abnormal operation mode. Preferably, no closed-loop or closed-loop control by the adjustable expansion device is also performed. In this proposed invention, the opening cross-section of the valve in the first position is smaller than the opening cross-section of the valve in the second position.

[0027] When a two-way solenoid valve is used as a valve, the first position may be the shut-off position, while the second position may be the flow-through position. If other configurations of the valve are used that have a continuously changeable opening cross-section or an opening cross-section that can be changed in discrete steps, any partial opening can be performed at the first and / or second positions.

[0028] In this proposed invention, the compressor operates continuously within the laboratory centrifuge while it is in operation. In this case, during operation, the rotational speed always matches at least one minimum rotational speed. Therefore, the need to stop the compressor can be avoided by this configuration of the present invention. This is beneficial on the one hand for the operation, lifespan, and lubrication of the compressor, and on the other hand for avoiding unwanted mixing of the centrifugal contents caused by stopping and restarting the compressor.

[0029] A further solution of the present invention is to provide a method for operating a centrifuge. In this case, the centrifuge is basically configured as described in the different and other configurations above. In one method step, it is first checked whether the difference between the set temperature inside the centrifuge and the temperature detected by the temperature sensor is greater than a threshold. If it is confirmed that the difference is greater than the threshold, the flow rate through the bypass piping is increased in the method of the present invention.

[0030] In this proposed invention, the method involves open-loop or closed-loop control of the flow rate of refrigerant flowing to a compressor and a passive thermostatic injection valve (or either the compressor or the thermostatic injection valve).

[0031] In the method of the present invention, the refrigerant can be transported in the refrigerant circuit by a rotary piston compressor.

[0032] Furthermore, in the method of the present invention, the valve can be controlled (continuously or discretely in steps) to a plurality of different opening cross-sections. In this case, the opening cross-section is enlarged when the difference between the set temperature in the centrifuge and the temperature detected by the temperature sensor is greater than a threshold. In this case, the enlargement and the degree of such enlargement depend on the calculated absolute value of the difference, the rate of change of the difference, and / or the period during which the difference is greater than the threshold.

[0033] According to the present invention, it is checked whether the difference between the set temperature inside the centrifuge and the temperature detected by the temperature sensor is smaller than a threshold (or another second threshold).

[0034] If the difference is less than the threshold (or another secondary threshold), the centrifuge operates in normal operating mode. In normal operating mode, open-loop or closed-loop control is performed by the adjustable expansion and / or compressor.

[0035] Conversely, if the difference is greater than a threshold (or a second threshold), the centrifuge operates in abnormal operation mode. In abnormal operation mode, the valve is controlled to a second position different from the first position. Therefore, in abnormal operation mode, open-loop or closed-loop control by the compressor is not performed. In this case, preferably, open-loop or closed-loop control by the adjustable expansion device is not performed. In the configuration of the method of the present invention, in the first position of the valve, the opening cross-section of the valve is smaller than the opening cross-section of the valve in the second position.

[0036] In another configuration of the method of the present invention, the compressor is operated continuously while the centrifugal separator is operating. In this case, the rotational speed during operation matches at least one minimum rotational speed.

[0037] A further object of the present invention is to provide a computer-readable medium having a control logic unit for performing the method for operating a centrifuge as described above. The control logic unit of such a computer-readable medium makes it possible, for example, to perform the method of the present invention on an existing centrifuge or to upgrade the control software retrospectively.

[0038] The advantages of the features described in the specification and the advantages of combinations of multiple features are illustrative only, and such advantages are not achieved solely by embodiments of the present invention, but can also be achieved by performing substitutions or combinations.

[0039] With respect to disclosures outside the scope of the original patent application, the following applies: further features can be inferred from the drawings—in particular the illustrated structures, the relative dimensions of multiple components, and the relative arrangement and function of these components. Furthermore, combinations of features of multiple different embodiments of the invention or combinations of multiple different claims in the claims are possible and applicable here, even if they differ from the reference relationships of selected claims in the claims. This also applies to multiple features shown in individual figures or multiple features mentioned in the descriptions of these figures. These features may be combined with features of different claims in the claims. Also, features described in the claims may be omitted for other embodiments of the invention. However, such omissions do not apply to independent claims of a patented patent.

[0040] The features described in the claims and specification may be interpreted as including that number or a greater number, unless the adverb “at least” is explicitly used. Therefore, for example, a description relating to a valve or inflation device may be interpreted as including exactly one valve or inflation device, two valves or inflation devices, or more valves or inflation devices. The features described in the claims may be supplemented by other features or may be inherent features of the subject matter of each claim.

[0041] The symbols used in the claims do not limit the scope of the subject matter protected by the claims. They are used solely to facilitate understanding of the claims.

[0042] The present invention will be further described below based on preferred embodiments shown in the drawings. [Brief explanation of the drawing]

[0043] [Figure 1] A schematic diagram of a laboratory centrifuge with a refrigerant circuit using conventional technology is shown. [Figure 2] A schematic diagram of an experimental centrifuge having a refrigerant circuit according to European Patent No. 2814617 is shown. [Figure 3] A schematic diagram of a centrifugal separator with a refrigerant circuit is shown. [Figure 4] A schematic diagram of the method for operating a centrifugal separator with a refrigerant circuit is provided. [Modes for carrying out the invention]

[0044] Figure 3 schematically shows a centrifugal separator 19 having a centrifugal separator bowl 3 and a refrigerant circuit 1. In the refrigerant circuit 1, a compressor 4, a condenser 5, an expansion device 6 which may be configured as a thermostatic injection valve 7 or an electronically controlled expansion device or throttle 11, and an evaporator 2 are connected to each other in a ring in this order. A connecting pipe 17 between the compressor 4 and the condenser 5 is connected to a connecting pipe 16 between the expansion device 6 and the evaporator 2 via a bypass pipe 15 which has an electronically controlled valve 20 located in the bypass pipe 15. If the expansion device 6 is configured as a thermostatic injection valve 7, the thermostatic injection valve 7 preferably includes a pressure-controlled temperature detection unit 8 having springs 9 and 10 (see Figure 1 and the prior art described at the beginning).

[0045] The method of the present invention is shown in Figure 4. First, the centrifugal separator 19 is operated in normal operating mode 21 (possibly after the operation of the centrifugal separator 19 is started). In normal operating mode, temperature control in the centrifugal separator bowl 3 is performed in method step 22. In this control, first, the flow of the refrigerant and the opening amount or throttling effect amount of the expansion device 6 are controlled. This is performed when a thermostatic injection valve 7 is used as the expansion device 6, as described with respect to the passive method. However, the temperature in the centrifugal separator bowl 3 may also be measured by a temperature sensor 23, and an electronic injection valve or electronic throttle 11 may be driven by the control device as needed. Alternatively or further, open-loop or closed-loop control of the temperature may be performed by driving a compressor 4 controllable using the control device. In method step 24, which may be performed during the open-loop or closed-loop control described above, the difference between a preset temperature in the centrifuge bowl (for example, entered by the user and stored in the control unit, or read from a characteristic map for selected operating data) and the temperature detected by the temperature sensor 23 (i.e., the actual temperature (in this case, the measured temperature may be corrected or converted to the actual temperature of the centrifugal chamber inside the centrifuge 3 or an estimate of this actual temperature)) is calculated. Then, in method step 25, this difference is compared to a threshold, which may be, for example, 5K, 3K, or 1K. If this difference is less than the threshold, i.e., the actual temperature is lower than the preset temperature by less than the threshold, the normal operating mode 21, in which method step 21 is repeated, may continue.

[0046] Conversely, if the difference between the set temperature and the actual temperature is greater than a threshold, i.e., if the actual temperature is lower than the set temperature by more than a threshold, the normal operation mode 21 is switched to abnormal operation mode 26. In abnormal operation mode 26, in method step 27, the valve 20 is controlled by the control device so that the flow rate in the bypass piping 15 is increased. The valve 20 may be configured as a two-way solenoid valve. In this case, in method step 27, the two-way solenoid valve 28 is driven so that it moves from the closed position to the open position. Optionally, in method step 29, other measures may be taken to raise the actual temperature. This can be done, for example, by appropriately driving the controllable compressor 4 and / or expansion device 6. This condition may be maintained for a predetermined period of time. Immediately after or after this period, in method step 30, it is checked whether the difference between the set temperature and the actual temperature is still greater than a threshold. If the temperature remains above the threshold, the abnormal operation mode 26 is maintained, and in method step 27, the valve 20 is opened, opened further than before, or the valve 20 remains open. Conversely, if the actual temperature has risen to the point where it is at most below the set temperature by the threshold, the system returns to normal operation mode 21. This causes method steps 22, 24, and 25 to be performed again.

[0047] In the bypass piping 15, the valve 20 may be connected in parallel with the piping section or may have a slot having a predetermined throttle cross-section. This ensures a constant flow rate through the bypass piping 15. In this case, the thus guaranteed flow rate can be further controlled depending on the open position of the valve 20. Even in this case, the valve 20 may be configured as a two-way solenoid valve or as any other discrete or continuously adjustable valve.

[0048] Preferably, the compressor 4 may be configured as a rotary piston compressor 31. Although this application relates to the invention described in the claims, it may also encompass the following configurations as other embodiments. 1. a) Centrifugal bowl (3), b) A refrigerant circuit (1) having a circulating refrigerant, c) A temperature sensor (23) that detects a temperature that is at least correlated with the temperature inside the centrifugal separator bowl (3), A centrifuge (19) equipped with, in particular a continuous centrifuge, a biotechnology centrifuge or a blood centrifuge, c) The refrigerant circuit (1) is, ca) A controllable compressor (4), cb) Condenser (5), cc) Variable expansion device (6), cd) an evaporator (2) for cooling the centrifugal separator bowl (3), It has, d) The connecting pipe (17) that connects the compressor (4) to the condenser (5) is connected via a bypass pipe (15) to the connecting pipe (16) between the expansion device (6) and the evaporator (2), e) In the centrifuge (19) in which an electronically controlled valve (20) for controlling the flow rate is located in the bypass piping (15), f) There exists an electronic control device having a control logic unit, - The set temperature inside the centrifugal separator bowl (3), -When the difference between the temperature detected by the temperature sensor (23) and the threshold is greater than the threshold, the control logic unit controls the valve (20) so that the flow rate through the bypass pipe (15) increases. g) The control device has a control logic unit, ga) - The set temperature inside the centrifugal separator bowl (3), -In the normal operating mode (21), where the absolute value of the difference between the temperature detected by the temperature sensor (23) and the threshold or the second threshold is smaller than the threshold, The control logic unit performs open-loop control and / or closed-loop control by the expansion device (6) and / or the compressor (4) while the valve (20) is in the first position. gb) - The set temperature inside the centrifugal separator bowl (3), -In abnormal operating mode (26) where the absolute value of the difference between the temperature detected by the temperature sensor (23) and the temperature is greater than the threshold or the second threshold, The control logic unit operates the valve (20) to a second valve position different from the first position, and in this abnormal operation mode (26), does not perform open-loop control and closed-loop control by the compressor (4), preferably, in this abnormal operation mode (26), does not perform open-loop control and closed-loop control by the expansion device (6) either. gc) The centrifuge (19) wherein, in the first position of the valve (20), the opening cross-section of the valve (20) is smaller than the opening cross-section of the valve (20) in the second position. 2. a) The valve (20) is a two-way solenoid valve (28) having a larger open position and a smaller open position, and in particular a flow-through position and a shut-off position. b) The control logic unit has a control logic unit, - The set temperature inside the centrifugal separator bowl (3), -When the difference between the temperature detected by the temperature sensor (23) and the threshold is greater than the threshold, the control logic unit operates the two-way solenoid valve (28) from a smaller open position to a larger open position, preferably the control logic unit controls the two-way solenoid valve (28) from a smaller open position to a larger open position over a predetermined period of time, as described in 1 above, for the centrifugal separator (19). 3. The expansion device (6) is a centrifuge (19) according to 1 or 2 above, which is a passive thermostat-type injection valve (7). 4. The compressor (4) is a rotary piston compressor (31), which is the centrifugal separator (19) described in any one of the above 1 to 3. 5. The valve has a plurality of different opening cross-sections, and the control device has a control logic unit. - The set temperature inside the centrifugal separator bowl (3), -When the difference between the temperature detected by the temperature sensor (23) and the opening cross-section is greater than a threshold, the control logic unit increases the opening cross-section depending on the absolute value of the difference, the rate of change of the difference and / or the period during which the difference is greater than the threshold, as described in claims 1, 3 and 4. 6. The compressor (4) operates continuously while the centrifugal separator (19) is in operation. A centrifuge (19) according to any one of claims 1 to 5, wherein during operation, the rotational speed always matches at least one minimum rotational speed. 7. A centrifugal separator bowl (3), a refrigerant circuit (1) having a circulating refrigerant, and a temperature sensor (23) that detects a temperature at least correlated with the temperature inside the centrifugal separator bowl (3), A method for operating a centrifuge (19) equipped with, in particular a continuous centrifuge, a biotechnology centrifuge or a blood centrifuge, The refrigerant circuit (1) includes a controllable compressor (4), a condenser (5), an expansion device (6), and an evaporator (2) for cooling the centrifugal separator bowl (3). The connecting pipe (17) that connects the compressor (4) to the condenser (5) is connected via a bypass pipe (15) to the connecting pipe (16) between the expansion device (6) and the evaporator (2). An electronically controlled valve (20) that controls the flow rate is located in the bypass piping (15), The above method is as follows: a) A method step of checking whether the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is greater than a threshold, b) A method step of increasing the flow rate through the bypass piping (15) if, as a result of the inspection, the difference is greater than the threshold, c) It is checked whether the absolute value of the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is smaller than the threshold or the second threshold. ca) If the absolute value of the difference is less than the threshold or the second threshold, the centrifugal separator (19) is operated in normal operating mode (21), in which open-loop control and / or closed-loop control are performed by the expansion device (6) and / or the compressor (4) while the valve (20) is in the first position. cb) If the absolute value of the difference is not less than the threshold or the second threshold, the centrifuge (19) is operated in abnormal operation mode (26), and this abnormal operation In the rotation mode (26), the valve (20) is operated to a second valve position different from the first position, and in this abnormal operation mode (26), open-loop control and / or closed-loop control by the compressor (4) is not performed, preferably, in this abnormal operation mode (26), open-loop control and / or closed-loop control by the expansion device (6) is also not performed. The method wherein, in the first position of the valve (20), the opening cross-section of the valve (20) is smaller than the opening cross-section of the valve (20) in the second position. 8. The method according to the above 7, wherein the flow rate of the refrigerant flowing through the evaporator (2) is controlled by a passive thermostat-type injection valve (7) to be either open-loop or closed-loop controlled. 9. In the refrigerant circuit (1), the refrigerant is discharged by a rotary piston compressor (31) according to the method described in 7 or 8 above. 10. a) The valve (20) is controlled to have multiple different opening cross-sections, b) It is checked whether the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is greater than a threshold. The method according to any one of 7 to 9 above, wherein, when the difference is greater than a threshold, the opening cross-section is increased depending on the absolute value of the difference, the rate of change of the difference, and / or the period during which the difference is greater than the threshold. 11. The compressor (4) operates continuously while the centrifugal separator (19) is in operation. The method according to any one of claims 7 to 10, wherein during the operation, the rotational speed always matches at least one minimum rotational speed. 12. A computer-readable medium having a control logic unit for performing the method according to any one of claims 7 to 11 for operating a centrifuge (19), in particular a continuous centrifuge, a centrifuge for biotechnology, or a centrifuge for blood. [Explanation of symbols]

[0049] 1. Refrigerant circuit 2 Evaporator 3. Centrifugal bowl 4. Compressor 5. Condenser 6. Expansion device 7. Thermostatic injection valve 8. Pressure-controlled temperature detection unit 9 Spring 10 sensors 11. Electronically controlled expansion device or electronically controlled throttle 12 Temperature Sensors 13 Temperature sensor 14. Temperature sensor 15 Bypass piping 16. Connecting pipes 17. Connecting pipes 18 Electronically controlled injection valve 19. Centrifugal separator 20 valves 21 Normal operation mode 22 Method Steps 23 Temperature Sensor 24 Method Steps 25 Method Steps 26 Abnormal Operation Mode 27 Method Steps 28 Two-way solenoid valve 29 Method Steps 30 Method Steps 31 Rotary Piston Compressor

Claims

1. a) Centrifuge bowl (3) and b) A refrigerant circuit (1) having a circulating refrigerant, c) A temperature sensor (23) that detects a temperature that is at least correlated with the temperature inside the centrifugal separator bowl (3), A centrifuge (19) equipped with, in particular a continuous centrifuge, a centrifuge for biotechnology or a centrifuge for blood, c) The refrigerant circuit (1) is, ca) A controllable compressor (4) cb) Condenser (5) and, cc) Variable expansion device (6), cd) Evaporator (2) for cooling the centrifugal separator bowl (3), It has, d) The connecting pipe (17) that connects the compressor (4) to the condenser (5) is connected via a bypass pipe (15) to the connecting pipe (16) between the expansion device (6) and the evaporator (2), e) In the centrifugal separator (19) in which an electronically controlled valve (20) for controlling the flow rate is located in the bypass piping (15), f) An electronic control device exists that has a control logic unit, and this control logic unit is - The set temperature inside the centrifugal separator bowl (3), - When the difference between the temperature detected by the temperature sensor (23) and the actual temperature is greater than a threshold, the valve (20) is controlled to increase the flow rate through the bypass pipe (15). g) The control logic unit is: ga) - The set temperature inside the centrifugal separator bowl (3), - In the normal operating mode (21), where the absolute value of the difference between the temperature detected by the temperature sensor (23) and the actual temperature is smaller than the threshold or the second threshold, While the valve (20) is in the first position, open-loop control or closed-loop control is performed by the expansion device (6) and / or the compressor (4). gb) - The set temperature inside the centrifugal separator bowl (3), - In abnormal operating mode (26), where the absolute value of the difference between the temperature detected by the temperature sensor (23) and the actual temperature is greater than the threshold or the second threshold, The valve (20) is operated to a second position different from the first position, and in this abnormal operation mode (26), neither open-loop control nor closed-loop control is performed by the compressor (4). gc) A centrifugal separator (19) characterized in that, in the first position of the valve (20), the opening cross-section of the valve (20) is smaller than the opening cross-section of the valve (20) in the second position.

2. The centrifugal separator (19) according to claim 1, wherein in the abnormal operating mode (26), neither open-loop control nor closed-loop control is performed by the expansion device (6).

3. a) The valve (20) is a two-way solenoid valve (28) having a larger open position and a smaller open position, b) The control logic unit has a control logic unit, - The set temperature inside the centrifugal separator bowl (3), - The centrifugal separator (19) according to claim 1, characterized in that when the difference between the temperature detected by the temperature sensor (23) and the actual temperature is greater than a threshold, the control logic unit controls the two-way solenoid valve (28) from a smaller open position to a larger open position.

4. a) The valve (20) is a two-way solenoid valve (28) having a larger open position and a smaller open position, b) The control logic unit has a control logic unit, - The set temperature inside the centrifugal separator bowl (3), - The centrifugal separator (19) according to claim 2, characterized in that when the difference between the temperature detected by the temperature sensor (23) and the actual temperature is greater than a threshold, the control logic unit controls the two-way solenoid valve (28) from a smaller open position to a larger open position.

5. The centrifuge (19) according to claim 3, characterized in that the control logic unit controls the two-way solenoid valve (28) from a smaller open position to a larger open position over a predetermined period of time.

6. The centrifuge (19) according to claim 4, characterized in that the control logic unit controls the two-way solenoid valve (28) from a smaller open position to a larger open position over a predetermined period of time.

7. The centrifugal separator (19) according to claim 3, characterized in that a larger opening position is a flow-through position, and a smaller opening position is a shut-off position.

8. The centrifugal separator (19) according to claim 4, characterized in that a larger opening position is a flow-through position, and a smaller opening position is a shut-off position.

9. The centrifugal separator (19) according to any one of claims 1 to 8, characterized in that the expansion device (6) is a passive thermostat-type injection valve (7).

10. The centrifugal separator (19) according to any one of claims 1 to 8, characterized in that the compressor (4) is a rotary piston compressor (31).

11. The valve has a plurality of different opening cross-sections, and the control device has a control logic unit. - The set temperature inside the centrifugal separator bowl (3), - The centrifuge (19) according to claim 1, 2, 7, or 8, wherein if the difference between the temperature detected by the temperature sensor (23) and the current temperature is greater than a threshold, the control logic unit increases the size of the opening cross-section depending on the absolute value of the difference, the rate of change of the difference, and / or the period during which the difference is greater than the threshold.

12. The compressor (4) operates continuously while the centrifugal separator (19) is in operation. The centrifugal separator (19) according to any one of claims 1 to 8, wherein the rotational speed always matches at least one minimum rotational speed during operation.

13. A method for operating a centrifuge (19), particularly a continuous centrifuge, a biotechnology centrifuge, or a blood centrifuge, comprising a centrifuge bowl (3), a refrigerant circuit (1) having a circulating refrigerant, and a temperature sensor (23) for detecting a temperature that is at least correlated with the temperature inside the centrifuge bowl (3), The refrigerant circuit (1) includes a controllable compressor (4), a condenser (5), an expansion device (6), and an evaporator (2) for cooling the centrifugal separator bowl (3). The connecting pipe (17) that connects the compressor (4) to the condenser (5) is connected via a bypass pipe (15) to the connecting pipe (16) between the expansion device (6) and the evaporator (2). An electronically controlled valve (20) that controls the flow rate is located in the bypass piping (15), The above method is as follows: a) A method step of checking whether the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is greater than a threshold, b) A method step of increasing the flow rate through the bypass piping (15) if, as a result of the inspection, the difference is greater than the threshold, c) It is checked whether the absolute value of the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is smaller than the threshold or the second threshold. ca) If the absolute value of the difference is less than the threshold or the second threshold, the centrifugal separator (19) is operated in normal operation mode (21), in which open-loop control or closed-loop control is performed by the expansion device (6) and / or the compressor (4) while the valve (20) is in the first position. cb) If the absolute value of the difference is not less than the threshold or the second threshold, the centrifugal separator (19) is operated in abnormal operation mode (26), in which the valve (20) is operated to a second position different from the first position, and in which abnormal operation mode (26), neither open-loop control nor closed-loop control is performed by the compressor (4). The method wherein, in the first position of the valve (20), the opening cross-section of the valve (20) is smaller than the opening cross-section of the valve (20) in the second position.

14. The method according to 13, characterized in that, in the abnormal operation mode (26), neither open-loop control nor closed-loop control is performed by the expansion device (6).

15. The method according to 13, characterized in that the flow rate of the refrigerant flowing through the evaporator (2) is controlled by a passive thermostat-type injection valve (7) to be either open-loop or closed-loop controlled.

16. The method according to 14, characterized in that the flow rate of the refrigerant flowing through the evaporator (2) is controlled by a passive thermostat-type injection valve (7) to be either open-loop or closed-loop controlled.

17. The method according to 13, characterized in that the refrigerant in the refrigerant circuit (1) is discharged by a rotary piston compressor (31).

18. The method according to 14, characterized in that the refrigerant in the refrigerant circuit (1) is discharged by a rotary piston compressor (31).

19. a) The valve (20) is controlled to have multiple different opening cross-sections, b) It is checked whether the difference between the set temperature in the centrifugal separator bowl (3) and the temperature detected by the temperature sensor (23) is greater than a threshold. The method according to any one of claims 13 to 18, characterized in that, when the difference is greater than a threshold, the opening cross-section is increased depending on the absolute value of the difference, the rate of change of the difference, and / or the period during which the difference is greater than the threshold.

20. The compressor (4) operates continuously while the centrifugal separator (19) is in operation. The method according to any one of claims 13 to 18, wherein during the operation, the rotational speed always matches at least one minimum rotational speed.

21. A computer-readable medium having a control logic unit for performing the method according to any one of claims 13 to 18 for operating a centrifuge (19), in particular a continuous centrifuge, a centrifuge for biotechnology, or a centrifuge for blood.

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