Continuous flow centrifugation with controlled positive pressure cascade to avoid cross-contamination

Abstract

A control system for a centrifuge is disclosed that includes a controller that receives a first pressure signal indicative of a first pressure of a product flowing into or out of the centrifuge and a second pressure signal indicative of a second pressure of a working fluid flowing into or out of the centrifuge. The controller is configured to determine a first pressure differential between the first and second pressures and, in response to the first pressure differential falling below a first predetermined offset, output a first control signal that increases a backpressure of the product flowing out of the centrifuge.

Description

[Technical Field]

[0001] The present invention relates generally to continuous centrifugation of products, and more particularly to a method for controlling a centrifugation system to prevent cross-contamination of products. [Background technology]

[0002] A continuous-flow centrifuge typically includes a rotor with an input port and an output port, and fixed connections that provide the rotor with a sample to be processed and accept separated sample components from the rotor. As the rotor rotates relative to these fixed connections, a seal assembly is used to couple the connections to the spin rotor. During centrifugation, the sample flows through the fixed connections and seal assembly into the rotor, and the sample separates into its component parts due to density caused by g-forces generated within the rotor.

[0003] To reduce heat and prevent damage to the seal assembly, the union seals joining the rotor ports to the stationary connections are cooled and lubricated by one or more working fluids. The working fluid is typically provided to the seal assembly under pressure by an external cooling and lubrication system. However, because the working fluid is under pressure, if any of the seals in the seal assembly are defective, the sample components being processed by the centrifuge may become contaminated by the working fluid.

[0004] One way to determine whether the working fluid may be contaminating the product in the centrifuge is by detecting leaks. Working fluid leaks may be detected, for example, by monitoring the working fluid reservoir for the level or weight of its contents. However, even when a leak is successfully detected in this manner, the detection of the leak does not prevent contamination. Rather, the detection merely informs the operator that the product may be contaminated.

[0005] Therefore, there is a need for improved systems, methods, and computer program products for detecting and preventing contamination in continuous centrifugation systems. Summary of the Invention

[0006] The present invention overcomes the above-mentioned and other shortcomings and drawbacks of previously known methods for detecting contamination in separated products for use in centrifugation. Although the present invention will be discussed in connection with certain embodiments, it will be understood that the invention is not limited to the specific embodiments described herein.

[0007] In one embodiment of the present invention, a control system for a centrifuge is provided. The control system includes a controller that receives a first pressure signal indicative of a first pressure of a product flowing into or out of the centrifuge and a second pressure signal indicative of a second pressure of a working fluid flowing into or out of the centrifuge. The controller is configured to determine a first pressure differential between the first and second pressures and, in response to the first pressure differential falling below a first predetermined offset, output a first control signal to increase the backpressure of the product flowing out of the centrifuge.

[0008] In one aspect of the invention, the controller is configured to output a second control signal that reduces the backpressure of the product exiting the centrifuge in response to the first pressure differential increasing above a second predetermined offset.

[0009] In another aspect of the invention, a first control signal increases the back pressure by closing the valve, and a second control signal decreases the back pressure by opening the valve.

[0010] In another aspect of the invention, the first predetermined offset is less than or equal to the second predetermined offset.

[0011] In another aspect of the invention, the first pressure is of the product entering the centrifuge, and the controller is configured to receive a third pressure signal indicative of a third pressure of the product exiting the centrifuge, determine a second pressure differential between the first pressure and the third pressure, and output a third control signal to increase the backpressure of the product entering the centrifuge in response to the second pressure differential falling below a third predetermined offset.

[0012] In another aspect of the invention, the third control signal increases the back pressure of the product entering the centrifuge by closing a valve.

[0013] In another aspect of the invention, the second pressure is of the lubricant, and the controller is further configured to receive a fourth pressure signal indicative of a fourth pressure of the coolant, determine a third pressure difference between the first pressure and the fourth pressure, and output the first control signal in response to either the first pressure difference falling below a first predetermined offset or the third pressure difference falling below a fourth predetermined offset.

[0014] In another aspect of the invention, the controller is further configured to store data indicative of the first pressure, the second pressure, and an operating state of the centrifuge at each of a plurality of sample times during which the centrifuge is operating.

[0015] In another aspect of the invention, the controller determines that the components of the product are not contaminated based on the first pressure differential not falling below a fifth predetermined offset during the period when the centrifuge was processing the product.

[0016] In another aspect of the invention, the fifth predetermined offset is less than the first predetermined offset and greater than zero.

[0017] In another embodiment of the present invention, a method for controlling a centrifuge is provided, the method including receiving a first pressure signal indicative of a first pressure of a product flowing into or out of the centrifuge, receiving a second pressure signal indicative of a second pressure of a working fluid flowing into or out of the centrifuge, determining a first pressure differential between the first and second pressures, and increasing a backpressure of the product flowing out of the centrifuge in response to the first pressure differential falling below a first predetermined offset.

[0018] In another aspect of the invention, the method further includes reducing backpressure of the product exiting the centrifuge in response to the first pressure differential increasing above a second predetermined offset.

[0019] In another aspect of the invention, increasing the backpressure comprises closing a valve, and decreasing the backpressure comprises opening a valve.

[0020] In another aspect of the invention, the first predetermined offset is less than or equal to the second predetermined offset.

[0021] In another aspect of the invention, the first pressure is of the product entering the centrifuge, and the method further includes receiving a third pressure signal indicative of a third pressure of the product exiting the centrifuge, determining a second pressure differential between the first pressure and the third pressure, and increasing the backpressure of the product entering the centrifuge in response to the second pressure differential falling below a third predetermined offset.

[0022] In another aspect of the invention, increasing the backpressure of the product entering the centrifuge includes closing a valve.

[0023] In another aspect of the invention, the second pressure is of the lubricant, and the method further includes receiving a fourth pressure signal indicative of a fourth pressure of the coolant; determining a third pressure differential between the first pressure and the fourth pressure; and increasing the backpressure of the product exiting the centrifuge in response to either the first pressure differential falling below a first predetermined offset or the third pressure differential falling below a fourth predetermined offset.

[0024] In another aspect of the invention, the method further includes storing data indicative of the first pressure, the second pressure, and an operating state of the centrifuge at each of a plurality of sample times during which the centrifuge is operating.

[0025] In another aspect of the invention, the method further includes determining that the components of the product are not contaminated based on the first pressure differential not falling below a fifth predetermined offset during the time period that the centrifuge was processing the product.

[0026] In another aspect of the invention, the fifth predetermined offset is less than the first predetermined offset and greater than zero.

[0027] In another embodiment of the present invention, a computer program product for controlling a centrifuge is provided. The computer program product includes a non-transitory computer-readable storage medium and program code stored on the non-transitory computer-readable storage medium. The program code, when executed by one or more processors, is configured to cause the one or more processors to receive a first pressure signal indicative of a first pressure of a product flowing into or out of the centrifuge, receive a second pressure signal indicative of a second pressure of a working fluid flowing into or out of the centrifuge, determine a first pressure difference between the first pressure and the second pressure, and increase a backpressure of the product flowing out of the centrifuge in response to the first pressure difference falling below a first predetermined offset. [Brief explanation of the drawings]

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description given below, serve to explain the invention. [Figure 1] FIG. 1 is a schematic diagram of an exemplary operating environment including a controller and a centrifuge having upper and lower seal assemblies in accordance with an exemplary embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the lower seal assembly of FIG. 1. [Figure 3] FIG. 2 is a schematic cross-sectional view of the upper seal assembly of FIG. 1. [Figure 4] 2 is a diagram of a control process that may be implemented by the controller of FIG. 1 to control the pressure of the product being processed by the centrifuge. DETAILED DESCRIPTION OF THE INVENTION

[0029] Embodiments of the present invention are directed to methods and systems for controlling a continuous-flow centrifuge. A control system monitors the pressure of a sample suspension fed to the centrifuge and the pressure of one or more separated components discharged from the centrifuge, collectively referred to as the "product." The control system also monitors the pressure of working fluids (e.g., coolants and lubricants) used to cool and lubricate the centrifuge's seals and bearings. Based on one or more of these monitored pressures, the control system adjusts the pressure of the product discharged from the centrifuge to maintain a positive pressure cascade across the seals. This positive pressure cascade prevents contamination of the input product or any output product in the event of a seal leak. That is, the input product and output product are each maintained at a pressure higher than the pressure of either of the working fluids, so that the working fluid cannot penetrate the area of ​​the seal assembly occupied by the product.

[0030] Multiple operating parameters, such as product characteristics and flow rate and rotor speed, can each affect the pressure of the product entering and exiting the centrifuge. However, by maintaining a positive product pressure relative to the working fluid pressure, the control system prevents product contamination at either the input or output of the centrifuge under all operating conditions. In addition to controlling pressure, the control system can also record operating data to document the absence of contamination risk for product verification and to facilitate problem tracking.

[0031] 1 depicts an operating environment 10 including a continuous-flow centrifuge 12 and a centrifuge controller 14 according to an exemplary embodiment of the invention. The centrifuge 12 may include a rotor housing 16 and a rotor 18 having a rotor body 20 that rotates within the rotor housing 16. The rotor 18 may further include a hollow lower shaft 22 having an input port 24 and a hollow upper shaft 26 having an output port 28. The rotor 18 may be operably coupled to a lower seal assembly 30 by the lower shaft 22 and to an upper seal assembly 32 by the upper shaft 26. A drive unit 34 may be coupled to the upper shaft 26 of the rotor 18 to provide rotation to the rotor 18. Each of the seal assemblies 30, 32 may be provided with a lubricant (e.g., oil) by a lubrication system 36 and a coolant (e.g., cooling water) by a cooling system 38.

[0032] The lower seal assembly 30 may fluidly couple the input port 24 of the rotor 18 to a supply line 40. The lower seal assembly 30 may be configured to allow the rotor 18 to rotate relative to the supply line 40. The supply line 40 may provide a flow of product to the rotor 18 by fluidly coupling the input port 24 of the rotor 18 to a product supply 42, e.g., a container of a biological suspension to be separated into component parts. The product supply 42 may be operably coupled to the supply line 40 by a pump 44 (e.g., a peristaltic pump) having an output port 46. The pump 44 may provide a controlled amount or flow rate of product under pressure to the supply line 40 in response to a control signal from the controller 14. The output of the supply line 40 may be coupled to the lower seal assembly 30 by a product input port 47.

[0033] The upper seal assembly 32 may fluidly couple the output port 28 of the rotor 18 to an output line 48 and is configured to allow the rotor 18 to rotate relative to the output line 48. The output line 48 may fluidly couple a product output port 49 of the seal assembly 32 to a component collection container 50. A valve 52 operably coupled to the output line 48 may regulate product flow between the output port 49 of the seal assembly 32 and the collection container 50. By way of example, the valve 52 may be a proportional control pinch valve used to control backpressure on the output line 48. To this end, the valve 52 may be selectively and incrementally opened and closed by the controller 14 to provide a controlled amount of resistance to product flow from the output port 49 of the seal assembly 32 into the collection container 50.

[0034] Drive unit 34 may be configured to selectively apply torque to rotor 18 via upper shaft 26, thereby rotating rotor 18 within rotor housing 16 in response to rotation control signals from controller 14. Drive unit 34 may include a high frequency induction motor or other suitable torque source that spins rotor 18 at speeds of, for example, up to 40,000 rotations per minute (RPM). This rotation may cause rotor 18 to generate a relative centrifugal force (RCF) of, for example, up to 118,000×g.

[0035] The lubrication system 36 may include an input port 54 and an output port 56, as well as one or more pumps, filters, heat exchangers, reservoirs, etc. (not shown) configured to provide lubricant under pressure to the seal assemblies 30, 32. A lubricant line 60 may fluidly couple the output port 56 of the lubrication system 36 to a respective lubricant input port 58 of each seal assembly 30, 32. The lubricant line 60 may also fluidly couple a lubricant output port 62 of each seal assembly 30, 32 to the input port 54 of the lubrication system 36. Thus, as the lubricant circulates through the seal assemblies 30, 32, the lubricant may return to the lubrication system 36 through its input port 54.

[0036] The cooling system 38 may include an input port 64 and an output port 66, as well as one or more pumps, filters, heat exchangers, reservoirs, etc. (not shown) configured to provide coolant under pressure to the seal assemblies 30, 32. Similar to that described above for the lubrication system 36, a coolant line 70 may fluidly couple the output port 66 of the cooling system 38 to a respective coolant input port 68 of each seal assembly 30, 32. The coolant line 70 may also fluidly couple a coolant output port 72 of each seal assembly 30, 32 to the input port 64 of the cooling system 38. Thus, as the coolant circulates through the seal assemblies 30, 32, the coolant may return to the cooling system 38 through the coolant system input port 64.

[0037] It should be understood that the lubricant and coolant lines may connect the seal assemblies 30, 32 in a series configuration (as shown), a parallel configuration, or any other suitable configuration. It should be further understood that the direction of working fluid flow indicated by arrows 74, 76 is exemplary only and may be varied in alternative embodiments of the present invention.

[0038] Pressure sensors 78-81 may be operably coupled to one or more of supply line 40, output line 48, lubricant line 60, and coolant line 70. The pressure sensors may be configured to provide pressure signals to controller 14 indicative of the pressure in each of the respective lines to which the respective pressure sensors are coupled. For example, lubricant pressure sensor 78 may be operably coupled to output port 56 of lubrication system 36, coolant pressure sensor 79 may be operably coupled to output port 66 of cooling system 38, product input pressure sensor 80 may be operably coupled to input port 24 of rotor 18, and product output pressure sensor 81 may be operably coupled to output port 28 of rotor 18.

[0039] The controller 14 may include a processor 90, a memory 92, an input / output (I / O) interface 94, and a human machine interface (HMI) 96. The processor 90 may include one or more devices selected from a microprocessor, a microcontroller, a digital signal processor, a microcomputer, a central processing unit, a field programmable gate array, a programmable logic device, a state machine, a logic circuit, an analog circuit, a digital circuit, or any other device that manipulates signals (analog or digital) based on operating instructions stored in the memory 92. The memory 92 may be a read-only memory (ROM), a random access memory (RRAM), or a access memory (RAM), volatile memory, non-volatile memory, static random access memory (static random access memory (SRAM), dynamic random access memory The memory may include a single memory device or multiple memory devices, including, but not limited to, dynamic random access memory (DRAM), flash memory, cache memory, or data storage devices such as hard drives, optical drives, tape drives, volatile or non-volatile solid state devices, or any other device capable of storing data.

[0040] The processor 90 may operate under the control of an operating system 98 that interfaces with the memory 92. The operating system 98 may manage controller resources such that computer program code embodied as one or more computer software applications 100 resident in the memory 92 may have instructions executed by the processor 90. One or more data structures 102 may also reside in the memory 92 and may be used by the processor 90, the operating system 98, or the applications 100 to store or manipulate data.

[0041] I / O interface 94 may provide a machine interface that operably couples processor 90 to one or more other devices and systems, such as drive unit 34, pump 44, valve 52, sensors 78-81, remote control device 104, and network 106. For example, I / O interface 94 may include one or more serial or parallel data ports (e.g., Profibus ports), one or more network communication ports (e.g., Ethernet ports or WiFi transceivers), and analog input and output ports for sending and receiving analog signals. Thus, application 100 may cooperate with other devices and systems by communicating via I / O interface 94 to provide various features, functions, applications, processes, or modules, including embodiments of the present invention.

[0042] Application 100 may also have program code that is executed by one or more external resources or that otherwise relies on functions or signals provided by other systems or network components external to controller 14. Indeed, given the nearly infinite number of possible hardware and software configurations, those skilled in the art will understand that embodiments of the present invention may include applications provided by computing resources (hardware and software) that are located external to controller 14, distributed across multiple computers or other external resources, or offered as a service over network 106, such as a cloud computing service.

[0043] The HMI 96 may be operably coupled to the processor 90 of the controller 14 to enable a user to directly interact with the controller 14. The HMI 96 may include a video or alphanumeric display, a touch screen, a speaker, and any other suitable audio and visual indicators capable of providing data to a user. The HMI 96 may also include input devices and controls, such as an alphanumeric keyboard, a pointing device, a keypad, push buttons, control knobs, a microphone, etc., capable of accepting commands or input from a user and transmitting the entered input to the processor 90. In one embodiment of the present invention, the HMI 96 may include or otherwise operate in cooperation with a remote control 104 to enable remote operation of the centrifuge 12.

[0044] The controller 14 may be operatively coupled to one or more external resources (not shown) via a network 106. The external resources may include, but are not limited to, servers, databases, mass storage devices, peripheral devices, cloud-based network services, or any other resources that may be used by the controller 14 to implement features of embodiments of the present invention.

[0045] In one embodiment of the present invention, the controller 14 may include a microcomputer, such as a Windows®-based PC controller. In this embodiment, the HMI 96 may include a touch-sensitive liquid crystal display (LCD) panel that provides a graphical user interface (GUI) for operating the centrifuge 12. The controller 14 may also be configured to support 21 CFR Part 11 regulations regarding electronic records, ensuring that operational data is handled securely and protected from corruption or tampering. Additionally, the controller 14 may be configured to output log data in CSV format via a Universal Serial Bus (USB) port or to a network shared folder for data management and analysis by commercially available database or spreadsheet software. The controller 14 may also support Ethernet OPC DA or Profibus-DP communication for monitoring real-time data and remote control operations.

[0046] In one embodiment of the present invention, the controller 14 can be connected to an external system, such as an Integrated Process Control (IPC), with a user interface that allows on-site programming of processes for rinsing, dispensing, separating, harvesting, cleaning, and sanitizing. These processes can be performed in fully automated, semi-automated, or manual modes. The external system can cover the centrifuge 12's user interface and control, monitor, and record the entire centrifugation process for consistent, repeatable sequences. This allows the external system to simplify operator training and reduce procedural errors. The external system can also be CFR 21 Part 11 compliant, with remote user management from a centralized Active Directory server, audit trails, a historian SQL database, and batch data reporting.

[0047] The external system communicates real-time process data with the site automation system via Object Linking and Embedding (OLE) for Process Control (OPC) and may consolidate to a site network domain and archive files on a shared folder for full backup. The external system may automatically shut off the product supply 42 when it is empty and may include pinch valves to control the product flow path, tanks for sampling, tanks for the supply input and supply output, and meters for measuring conductivity, temperature, absorbance, concentration, density, and mass flow rate.

[0048] 2 depicts an exemplary lower seal assembly 30 according to one embodiment of the present invention, including a shaft seal subassembly 120 and a union seal subassembly 122. The shaft seal subassembly 120 may include one or more shaft seals 124 that axially position the lower shaft 22 of the rotor 18 within a shaft channel 126 and prevent lubricant from leaking through the shaft 22. The lubricant input port 58 and the lubricant output port 62 of the lower seal assembly 30 may be fluidly coupled to the shaft seal 124 by respective lubricant channels 128, 130. The shaft seal 124 may thereby receive lubricant from the lubrication system 36, which lubricates and cools the shaft seal 124 during operation of the centrifuge 12.

[0049] The union seal subassembly 122 may include a lower union bearing 134 positioned within the union bearing channel 136 and a resilient member 138 (e.g., a spring) that biases the lower union bearing 134 in an upward direction within the union bearing channel 136. The lower union bearing 134 may be configured to move within the union bearing channel 136 in response to axially aligned (e.g., upward and downward) forces. During operation, the resilient member 138 may bias the lower union bearing 134 in an upward axial direction into facing engagement with the upper union bearing 140. The upper union bearing 140 may be operably coupled to the lower shaft 22 of the rotor 18 and configured to transfer the weight of the rotor 18 to the lower union bearing 134.

[0050] Lower union bearing 134 and upper union bearing 140 may be configured to provide a union seal 142 that allows lower shaft 22 to rotate relative to lower seal assembly 30. Lower union bearing 134 may include an axially aligned channel 144 that fluidly couples input port 24 of rotor 18 to product input port 47 of lower seal assembly 30 through a lower portion of union bearing channel 136.

[0051] The coolant input port 68 and the coolant output port 72 may be fluidly coupled to an upper portion of the union bearing channel 136 by respective coolant channels 146, 148. Coolant from the cooling system 38 may circulate around the lower union bearing 134 during operation of the centrifuge 12 to remove heat generated by friction between the lower union bearing 134 and the upper union bearing 140.

[0052] FIG. 3 depicts an exemplary upper seal assembly 32 according to one embodiment of the present invention. As described in more detail below, certain aspects of the upper seal subassembly 32 may resemble those of an inverted version of the lower seal assembly 30. The upper seal assembly 32 may include a shaft seal subassembly 150 and a union seal subassembly 152. The shaft seal subassembly 150 may include one or more shaft seals 154 that axially position the upper shaft 26 of the rotor 18 within a shaft channel 156 and prevent lubricant from leaking past the shaft 26. The lubricant input port 58 and the lubricant output port 62 of the upper seal assembly 32 may be fluidly coupled to the shaft seal 154 by respective lubricant channels 158, 160. The shaft seal 154 may thereby receive lubricant from the lubrication system 36, which lubricates and cools the shaft seal 154 during operation of the centrifuge 12.

[0053] The union seal subassembly 152 may include an upper union bearing 164 positioned within the union bearing channel 166 and a resilient member 168 (e.g., a spring) that biases the upper union bearing 164 in a downward direction within the union bearing channel 166. The upper union bearing 164 may be configured to move within the union bearing channel 166 in response to axially aligned (e.g., upward and downward) forces. During operation, the resilient member 168 may bias the upper union bearing 164 in a downward axial direction into opposing engagement with a lower union bearing 170 that is operably coupled to the upper shaft 26 of the rotor 18.

[0054] Upper union bearing 164 and lower union bearing 170 may be configured to provide a union seal 172 that allows upper shaft 26 to rotate relative to upper seal assembly 32. Upper union bearing 164 may include an axially aligned channel 174 that fluidly couples output port 28 of rotor 18 to product output port 49 of upper seal assembly 32 through an upper portion of union bearing channel 166.

[0055] The coolant input port 68 and the coolant output port 72 may each be fluidly coupled to an upper portion of the union bearing channel 166 by respective coolant channels 176, 178. Coolant from the cooling system 38 may circulate around the upper union bearing 164 during operation of the centrifuge 12 to remove heat generated by friction between the upper union bearing 164 and the lower union bearing 170.

[0056] 4 depicts a control process 200 that may be executed by the controller 14 or another suitable computing device to control the valve 52. The control process 200 may include an error function module 202 that receives pressure signals 204-207 indicative of pressure from each of the respective pressure sensors 78-81 and outputs an error signal 212 based at least in part on the pressure signals 204-207. The error signal 212 may be received by one or more of a proportional module 214, an integral module 215, and a derivative module 216. Each of the modules 214-216 may output a respective signal 220-222 that is summed to generate a control signal 226 used to control the valve 52. The control process 200 may thereby provide a proportional-integral-derivative (PID) control system that controls the operation of the valve 52.

[0057] Error function F 誤差 (t) may be configured to maintain one or more predetermined relationships between two or more of the product input pressure, product output pressure, lubricant pressure, and coolant pressure. 誤差 (t) is the product input pressure P (as indicated by sensor 80) I is the coolant pressure P (as indicated by sensor 79) C than a given offset Δ I-C That is, the pressure difference (P I -P C ) is the given offset Δ I-C In this case, the error function F 誤差(t) can be given by the following formula:

[0058]

number

[0059] As another example, the error function F 誤差 (t) is the product output pressure P (as indicated by sensor 81) O is the coolant pressure P (as indicated by sensor 79) C than a given offset Δ O-C That is, the pressure difference (P O -P C ) is the given offset Δ O-C In this case, the error function F 誤差 (t) can be given by the following formula:

[0060]

number

[0061] As yet another example, the error function F 誤差 (t) can be configured to output the minimum error (minimum positive error or maximum negative error) between the target product input and the coolant pressure difference, and between the target product output and the coolant pressure difference. In this case, the error function F 誤差 (t) can be given by the following formula:

[0062]

number

[0063] In either case, an error function F is used to control the pressure of the fluid entering and exiting the seal assembly. 誤差(t) may also include additional control features such as deadbands, hysteresis, limits, damping functions, etc. that are not represented in the exemplary equations.

[0064] An error signal 212 having a positive value may indicate that the product pressure is higher than required for one or more of the lubricant pressure and the coolant pressure. In this example scenario, modules 214-216 may be configured to generate signals 220-222 that, when summed, produce a control signal 226 that causes valve 52 to reduce the amount of backpressure. That is, control signal 226 may cause valve 52 to open more fully. Opening valve 52 may reduce the resistance experienced by the liquid exiting the centrifuge 12, thus reducing the backpressure at product output port 49 of upper seal assembly 32. This reduced backpressure at upper seal assembly 32 may propagate through rotor 18 and reduce the product pressure at product input port 47 of lower seal assembly 30.

[0065] In contrast, an error signal 212 having a negative value may indicate that the sample suspension pressure is too low relative to one or more of the lubricant and coolant pressures. In this exemplary scenario, modules 214-216 may be configured to generate signals 220-222 that, when summed, produce a control signal 226 that increases the amount of backpressure on valve 52. That is, control signal 226 may cause valve 52 to open less fully, i.e., to partially close. Closing valve 52 may increase the resistance experienced by the liquid exiting centrifuge 12, thus increasing the backpressure at product output port 49 of upper seal assembly 32. This increased backpressure at upper seal assembly 32 may propagate through rotor 18 and increase product pressure at product input port 47 of lower seal assembly 30.

[0066] The error function may be configured to cause the controller 14 to adjust the pressures of the product, lubricant, and coolant entering and exiting the centrifuge such that a predetermined relationship between the pressures of these fluids is maintained. For example, the error function may be configured to cause the controller to maintain the product input pressure at a level higher than the product output pressure and to maintain the product output pressure at a level higher than the coolant fluid pressure. That is, the product input and output pressures P I , P O can be controlled as follows: P I >P O >P C formula 4 The controller also controls the pressure of the lubricant to be higher than the coolant, i.e., P L >P C These relationships may be maintained by controlling one or more of the lubrication system 36, the cooling system 38, the pump 44, and the valve 52. Maintaining these relationships across different operating pressures may ensure product integrity without cross-contamination between the product and the centrifuge's operating fluid.

[0067] Embodiments of the present invention can provide good manufacturing practice (GMP) documented evidence of protection against cross-contamination risks by monitoring and storing pressure values ​​measured during centrifugation. This documentation can provide evidence of product cross-contamination-free status. Combining an automatic backpressure adjustment feature with a pressure sensor package that constantly monitors positive pressure across the union seal on the product line, embodiments of the present invention can provide sample security evidence and stream pressure data for verification and audit traceability.

[0068] Operating data stored by the system may include batch identification, batch start date and time, identification of who started the batch, batch stop date and time, identification of who stopped the batch, report generation date, equipment information, product information, product flow rate, volume, temperature, and pressure, and each operating fluid at each of one or more locations within the centrifuge system. Additional operating data stored by the system may include rotor speed, generated centrifugal force, product density, product concentration, product conductivity, or any other suitable data that can be used to characterize the operation of the centrifuge 12 and the processing of the product. In particular, the controller 14 may sample the pressure signals received from the sensors 78-81 at multiple sampling times (e.g., 44,100 times per second) over the period during which the centrifuge is processing a batch of product. The displayed pressure values ​​captured at each sample time may be stored in a database for use in generating pressure graphs and verifying the resulting separated components as free of contamination.

[0069] In general, the routines executed to implement embodiments of the present invention, whether implemented as part of an operating system, a specific application, component, program, object, module, or sequence of instructions, or a subset thereof, may be referred to herein as "computer program code" or simply "program code." Program code typically resides at different times in various memory and storage devices within a computer and comprises computer-readable instructions that, when read and executed by one or more processors within the computer, cause the computer to perform the operations necessary to carry out the operations or elements embodying various aspects of embodiments of the present invention. Computer-readable program instructions for carrying out operations of embodiments of the present invention may be, for example, assembly language, source code, or object code written in any combination of one or more programming languages.

[0070] Various program code described herein may be identified based on the application for which it is implemented within a particular embodiment of the invention. However, it should be understood that the specific program nomenclature below is used merely for convenience, and thus the present invention should not be limited to use with only the specific application identified or implied by such nomenclature. Furthermore, given the generally limitless number of ways in which computer programs may be organized into routines, procedures, methods, modules, objects, etc., as well as the various ways in which program functionality may be allocated among the various software layers (e.g., operating system, libraries, APIs, applications, applets, etc.) resident in a typical computer, it should be understood that embodiments of the present invention are not limited to the specific organization and allocation of program functionality described herein.

[0071] The program code embodied in any of the applications / modules described herein may be distributed individually or collectively as a computer program product in a variety of different forms. In particular, the program code may be distributed using a computer-readable storage medium having computer-readable program instructions thereon to cause a processor to perform aspects of embodiments of the present invention.

[0072] Computer-readable storage media that are non-transitory in nature may include volatile or nonvolatile, removable and non-removable tangible media implemented in any method or technology for storing data, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media may also include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid-state memory technology, portable compact disc read-only memory (CD-ROM) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store data and that can be read by a computer. Computer-readable storage media should not be interpreted as transient signals themselves (e.g., radio waves or other propagating electromagnetic waves, electromagnetic waves propagating through a transmission medium such as a waveguide, or electrical signals transmitted over wires). The computer-readable program instructions may be downloaded into a computer, another type of programmable data processing apparatus, or another device from a computer-readable storage medium, or over a network to an external computer or external storage device.

[0073] Computer-readable program instructions stored on a computer-readable medium can be used to instruct a computer, other type of programmable data processing apparatus, or other device to function in a specific manner, such that the instructions stored on the computer-readable medium produce an article of manufacture that includes instructions that implement the functions, acts, or operations specified in the flowchart, sequence diagram, or block diagram. The computer program instructions are provided to one or more processors of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine such that the instructions, executed by the one or more processors, cause the machine to perform a series of calculations to implement the functions, acts, or operations specified in the text of the specification, flowchart, sequence diagram, or block diagram.

[0074] The flowcharts and block diagrams depicted in the figures illustrate the architecture, functionality, or operation of possible implementations of systems, methods, or computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing a specified logical function(s).

[0075] In certain alternative embodiments, the functions, acts, or operations specified in a flowchart, sequence diagram, or block diagram may be rearranged, processed sequentially, or processed simultaneously, consistent with embodiments of the present invention. Furthermore, any flowchart, sequence diagram, or block diagram may include more or fewer blocks than illustrated, consistent with embodiments of the present invention. It should also be understood that each block of a block diagram or flowchart, or any combination of blocks in a block diagram or flowchart, may be implemented by a dedicated hardware-based system configured to perform the specified functions or acts, or may be executed by a combination of dedicated hardware and computer instructions.

[0076] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the present invention. As used herein, the singular forms "a," "an," and "the" are intended to include both the singular and the plural, and the terms "and" and "or" are each intended to include both alternatives and conjunctions unless the context clearly dictates otherwise. Furthermore, as used herein, it should be understood that the terms "comprises" or "comprising" specify the presence of stated features, integers, acts, steps, operations, elements, or components, but do not exclude the presence or addition of one or more other features, integers, acts, steps, operations, elements, components, or groups thereof. Furthermore, to the extent the terms "including," "having," "having," "comprising," or variations thereof are used in either the detailed description or the claims, such terms are intended to be inclusive as synonyms of the term "comprising."

[0077] While the description of various embodiments illustrates various aspects consistent with the principles of the present invention and has described the embodiments in considerable detail, it is not intended that the scope of the invention be limited to such details or in any way restricted. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.

Claims

1. 1. A control system for a centrifuge, comprising: a controller receiving a first pressure signal indicative of a first pressure of a product flowing into or out of the centrifuge and a second pressure signal indicative of a second pressure of a working fluid flowing into or out of the centrifuge, the controller comprising: determining a first pressure differential between the first pressure and the second pressure; a control system configured to output a first control signal to increase a backpressure of the product exiting the centrifuge in response to the first pressure differential falling below a first predetermined offset.

2. The controller:

10. The control system of claim 1, further configured to output a second control signal in response to the first pressure differential increasing beyond a second predetermined offset, the second control signal decreasing the backpressure of the product exiting the centrifuge.

3. 3. The control system of claim 2, wherein the first control signal increases the backpressure by closing a valve and the second control signal decreases the backpressure by opening the valve.

4. The control system of claim 2 , wherein the first predetermined offset is less than or equal to the second predetermined offset.

5. the first pressure being of the product entering the centrifuge, and the controller: receiving a third pressure signal indicative of a third pressure of the product exiting the centrifuge; determining a second pressure differential between the first pressure and the third pressure; 5. The control system of claim 1, further configured to output a third control signal to increase the backpressure of the product entering the centrifuge in response to the second pressure differential falling below a third predetermined offset.

6. 6. The control system of claim 5, wherein the third control signal causes an increase in the backpressure of the product entering the centrifuge by closing a valve.

7. the second pressure being of a lubricant, and the controller: receiving a fourth pressure signal indicative of a fourth pressure of the coolant; determining a third pressure differential between the first pressure and the fourth pressure; 7. The control system of claim 1, further configured to output the first control signal in response to either the first pressure differential falling below the first predetermined offset or the third pressure differential falling below a fourth predetermined offset.

8. The controller:

8. The control system of claim 1, further configured to store data indicative of the first pressure, the second pressure, and an operating state of the centrifuge at each of a plurality of sample times during which the centrifuge is operating.

9. 9. The control system of claim 1, wherein the controller determines that the components of the product are not contaminated based on the first pressure differential not falling below a fifth predetermined offset during a period in which the centrifuge is processing the product, the fifth predetermined offset being less than the first predetermined offset and greater than 0.

10. 1. A method of controlling a centrifuge, comprising: receiving a first pressure signal indicative of a first pressure of product entering or exiting the centrifuge; receiving a second pressure signal indicative of a second pressure of a working fluid entering or exiting the centrifuge; Determining a first pressure differential between the first pressure and the second pressure; and increasing a backpressure of the product exiting the centrifuge in response to the first pressure differential decreasing below a first predetermined offset.

11. 11. The method of claim 10, further comprising: decreasing the backpressure of the product exiting the centrifuge in response to the first pressure differential rising above a second predetermined offset, wherein increasing the backpressure comprises closing a valve and decreasing the backpressure comprises opening the valve, or wherein the first predetermined offset is less than or equal to the second predetermined offset.

12. the first pressure is of the product entering the centrifuge; receiving a third pressure signal indicative of a third pressure of the product exiting the centrifuge; determining a second pressure differential between the first pressure and the third pressure; 12. The method of claim 10 or 11, further comprising: increasing the backpressure of the product entering the centrifuge in response to the second pressure differential falling below a third predetermined offset.

13. 13. The method of any one of claims 10 to 12, wherein increasing the backpressure of the product entering the centrifuge comprises closing a valve.

14. the second pressure is of lubricant; receiving a fourth pressure signal indicative of a fourth pressure of the coolant; determining a third pressure differential between the first pressure and the fourth pressure; 14. The method of claim 10, further comprising: increasing the backpressure of the product exiting the centrifuge in response to either the first pressure differential falling below the first predetermined offset or the third pressure differential falling below a fourth predetermined offset.

15. 15. The method of claim 10, further comprising storing data indicative of the first pressure, the second pressure, and an operating state of the centrifuge at each of a plurality of sample times during which the centrifuge is operating.

16. 16. The method of claim 10, further comprising determining that the components of the product are not contaminated based on the first pressure differential not falling below a fifth predetermined offset during a period in which the centrifuge was processing the product, wherein the fifth predetermined offset is less than the first predetermined offset and greater than 0.

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