A rotary evaporator

Abstract

A rotary evaporator 1 comprising a pump 4, a control system 5, and a sensor 14 configured to measure a parameter associated with the pump and provide a signal to the controller 13 based on defined parameter values e.g., the pressure within the evaporation vessel 2. The control system determines whether an action is complete based on the signal and generates an appropriate output e.g., at completion of evaporation. There may also be a reagent reservoir 6 connected to the vessel by an inlet valve 17 for replenishment of reagent, the control parameter may be pressure within the vessel, rotational speed of the pump, reagent flow rate through the system or power consumption of the pump.

Description

FIELD The present teachings relate to a rotary evaporator, a control system for a rotary evaporator, and to a method of controlling a rotary evaporator. BACKGROUND Rotary evaporators are operated to remove a liquid material from a mixture via evaporation. Rotary evaporators are used in many chemical industries for a range of applications, for example, to purify and concentrate chemicals, or in distillation to separate components of mixture based on their boiling points. Typically, a rotary evaporator includes a vessel for housing the sample, and a heat source for providing heat to the sample in the vessel, and a pump to reduce the pressure within the vessel. The vessel is rotated while it is heated. Eventually, the solvent will evaporate and become liberated from the sample. The vessel is usually connected to a condenser, where the liberated solvent will be cooled and condensed into a liquid which is then collected. While rotary evaporators are an efficient means of separating a solvent from a sample, lab-based evaporators are usually ineffective when a large volume of mixture is to be treated. For example, it is often required that volume of mixture is many times the capacity of the vessel, meaning the process will have to be repeated numerous times in batches. Such an issue can be particularly cumbersome for an operator, who would be required to repeatedly introduce the sample, operate the evaporator, monitor the evaporator to identify when the evaporation process is complete and remove the materials from the vessel. The present teachings seek to provide an improved rotary evaporator. SUMMARY According to a first aspect of the invention, a rotary evaporator is provided, the rotary evaporator comprising: a vessel for receiving a mixture comprising a first liquid material and a second material; a heating device configured to heat the vessel for evaporating the first liquid material from the second material; a pump arranged and configured to control a pressure in the vessel; a control system configured to control the rotary evaporator, the control system comprising: a controller; and a sensor configured to measure a parameter associated with the pump and to provide a signal to the controller based on said parameter, wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate an output when it is determined that evaporation of the first liquid material has been completed. Advantageously, the rotary evaporator can be used to effectively separate a first liquid material from a second material. This recovery of the first liquid material can assist in improving the purity of the materials, and permit their re-use, reducing costs and environmental impact of many chemical processes. The control system as described detects when the first liquid material has been removed from the second material in response to an input based on a parameter of the pump. Utilising a parameter associated with the pump to determine when the evaporation is complete has been found to provide an accurate means of detecting completion of evaporation. Improving the accuracy of such a detection has been found to improve the automation of the evaporation process, preventing energy waste, and thus reducing the cost of using the evaporator. In exemplary embodiments, the vessel comprises an inlet connectable to a mixture reservoir, and wherein the controller is configured to instruct the rotary evaporator to draw a predetermined volume of mixture into the vessel from the mixture reservoir when it is determined that evaporation of the first liquid material has been completed. Advantageously, the rotary evaporator can be automated to introduce a volume of mixture into the evaporator for further treatment. The predetermined volume can be based numerous factors, including the capacity of the vessel. Such an arrangement improves the automation of the evaporator, and reduces the involvement of operator required, thereby permitting the evaporator to operate to treat a large volume of a mixture when no operators are present (e.g. overnight). The resource requirements of the evaporator and evaporation process is thus reduced significantly. In exemplary embodiments, the inlet is connectable to the mixture reservoir via an inlet valve moveable between an open position and a closed position, wherein the controller is configured to move the valve to the open position when it is determined that evaporation of the first liquid material has been completed; optionally, wherein the inlet valve is a solenoid valve. Advantageously, the inlet valve has been found to provide a flexible and efficient means of introducing mixture into the vessel when desired, and can be accurately controlled by the controller, thereby increasing the efficiency of introducing the mixture into the vessel and reducing downtime between evaporation cycles. In exemplary embodiments, the controller is configured to instruct the pump to reduce the pressure in the vessel when it is determined that evaporation of the first liquid material has been completed, so as to draw the predetermined volume of mixture into the vessel from the mixture reservoir. Advantageously, the reduction in pressure encourages flow of the mixture into the vessel. The pump can facilitate quick movement of the mixture, thereby minimising downtime between evaporation cycles. Moreover, pumps are versatile and can handle a wide range of mixture types, therefore improving the versatility of the rotary evaporator to treat different types of mixtures. In exemplary embodiments, the controller is configured to determine whether the mixture reservoir is empty and in response thereto turn the rotary evaporator off. Advantageously, the controller can detect when all of the mixture in the reservoir has been used in the evaporator and then turn the evaporator off. This prevents the evaporator continuing to operate when there is no mixture left to treat. Such is particularly important when considering the heating device and the pump, which would otherwise be providing heat and reducing pressure until an operator turns the evaporator off. As such, a possible hazardous scenario is avoided, as well as avoiding wasted energy as the evaporator continues to needlessly operate. Moreover, this feature further enhances the reliability of the evaporator with minimal operator input. In exemplary embodiments, the pump is configured to reduce the pressure in the vessel to an evaporation pressure which is substantially constant during evaporation of the first liquid material. Advantageously, the reduction of the pressure in the vessel can reduce the boiling point of the liquid material in the mixture, thereby causing the first liquid material to evaporate at a lower temperature, and thus reducing the energy required for the heating device the evaporate the first liquid material, and reducing the overall time taken for the evaporator to separate the mixture. In exemplary embodiments, the controller is configured to request the pump to generate a pressure in the vessel below the evaporation pressure and to monitor the signal from the sensor in response to said request to determine whether evaporation of the first liquid material has been completed. Advantageously, instructing the pump to operate at a pressure lower than the evaporation pressure can cause the pump to attempt to meet a pressure beyond its operational capabilities. In this way, the controller can observe the signal from sensor associated with the pump to compare the difference between the instructions provided to the pump, and the output of the pump. Such an arrangement provides a more accurate indication of the progress of the evaporation, thereby further improving the automation of the rotary evaporator. Identifying that evaporation is ongoing in the rotary evaporator improves the ability of the control system to automate the process, since the controller can respond more quickly to changes, thus reducing any wasted time, or downtime in the evaporator and therefore reducing the operating cost of using the evaporator. In exemplary embodiments, the controller is configured to determine that evaporation of the first liquid material is occurring when the pump is unable to generate a pressure in the vessel below the evaporation pressure. Advantageously, in exemplary embodiments the controller can identify that evaporation is occurring based on the signal from the sensor. This identification prevents the evaporator from turning off too quickly, and ensures temperature and pressure are maintained as needed. As such, the separation is less likely to be incomplete, thereby improving the purity of the final products. In exemplary embodiments, the controller is configured to determine that evaporation of the first liquid material is completed when the pump is able to generate a pressure in the vessel below the evaporation pressure. Advantageously, the controller can effectively and accurately identify that the evaporation is complete based on the signal from the sensor. Specifically, since the pump is instructed to reduce pressure beyond the evaporation pressure, any parameter associated with the pump will indicate a significant effort is being exerted by the pump to both sustain the pressure during the evaporation, but also reduce the pressure further. However, once the evaporation process is complete, the pump will no longer be exerting effort against the evaporation of the first liquid material, and so will be able to reduce the pressure with relative ease. The parameter will indicate this change in the pump which will thus allow the controller to detect the end of the evaporation. In exemplary embodiments, the parameter comprises the pressure in the vessel. Utilising the pressure in the vessel has been found to be an accurate means for determining whether the evaporation of the first liquid material is complete and thus increasing the reliability of the evaporator and the quality of the separation. Such an arrangement is particularly advantageous when the controller has instructed the pump to reduce the pressure beyond the evaporation pressure. The controller can compare this instructed pressure with the pressure in the vessel. While the evaporation is ongoing, the pump will not be able to reduce the pressure in response to instruction from the controller. However, once the evaporation is over, the pump will be able to reduce the pressure as instructed, since the pump no longer has to overcome the evaporation of the first liquid material. As such, the controller can accurately determine evaporation is complete. In exemplary embodiments, the parameter comprises at least one of: flow rate of mixture passing through the pump, power consumption of the pump and rotational speed of the pump. Measuring one or more of these parameters provides an indication as to the effort or work exerted by the pump to generate the required pressure in the vessel. This has been found to provide a reliable indication to the controller as to the progress of the evaporation. Such an arrangement is particularly advantageous when the controller has instructed the pump to reduce the pressure beyond the evaporation pressure. Specifically, once the controller instructs the pump to attempt to decrease the pressure in the vessel, the effort / work exerted by the pump will increase, since the pump is required to both maintain the pressure in response to evaporation, and attempt to further reduce the pressure. Once the evaporation is complete, the pump is no longer required to work to overcome the pressure increase caused by evaporation and so the work / effort of the pump will reduce, thus causing a deviation in the parameter and allowing the controller to determine the evaporation has completed. In exemplary embodiments, the controller is configured to instruct the rotary evaporator to draw a predetermined volume of mixture into the vessel and to monitor the time taken to evaporate the first liquid material from the predetermined volume of mixture so as to determine an evaporation cycle time. Advantageously, determining an evaporation cycle time can further improve the precision of control provided by the controller. This is particularly advantageous when the evaporator is intended to process multiple batches of a mixture, since the determination of the cycle time can assist in determining how many batches have occurred, or whether the process is complete. In exemplary embodiments, the controller is configured to turn off the rotary evaporator when the time taken to evaporate the first liquid is less than the determined evaporation cycle time by a predetermined amount. Advantageously, the rotary evaporator can accurately detect when all of the mixture from a mixture reservoir has been separated in the evaporator, and then switch off the evaporator. This prevents the evaporator continuing to operate when there is no mixture left to treat. Such is particularly important when considering the heating device and the pump, which would otherwise be providing heat and reducing pressure until an operator turns the evaporator off. As such, a possible hazardous scenario is avoided, as well as avoiding wasted energy as the evaporator continues to needlessly operate. Moreover, this feature further enhances the reliability of the evaporator with minimal operator input. In exemplary embodiments, the mixture further comprises a third liquid material, and wherein the controller is configured to determine whether evaporation of the third liquid material has been completed based on the signal from the sensor and in response thereto instruct the pump and / or the heating device to operate so as to evaporate the first liquid material, and wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate the output when it is determined that evaporation of the first liquid material has been completed. Advantageously, the rotary evaporator can be utilised to separate more than two components without impacting the automation of the evaporator, or the quality of the resulting materials. This improves the flexibility of the evaporator for handling mixtures of different types. In exemplary embodiments, the rotary evaporator comprises an outlet for removing the first liquid material from the evaporator after evaporation, wherein the outlet is coupled to a removal pump, the removal pump configured to generate a negative pressure such that the first liquid material is drawn from the evaporator via the outlet; optionally, wherein the removal pump is the pump. Advantageously, the removal pump can facilitate quick movement of the first liquid material out of the evaporator. Moreover, pumps are versatile and can handle a wide range of fluid types, therefore improving the versatility of the rotary evaporator to treat different types of fluids. In exemplary embodiments, the outlet is coupled to the removal pump via an outlet valve moveable between an open position and a closed position, wherein the controller is configured to move the valve to the open position so as to remove the first liquid material from the rotary evaporator; optionally, wherein the outlet valve is a solenoid valve. Advantageously, solenoids provide precise and accurate control of valve operation, as well as having fast response time. As such, the process of removing the first liquid material from the evaporator can be accurately controlled by the controller. In exemplary embodiments, the removal pump is a peristaltic pump. Advantageously, peristaltic pumps have been found to be ideal for limiting contamination of fluids passing through, since the fluid will not come into contact with any parts of the pump besides a flexible tube. As such, the purity of the material is not adversely impacted by movement through the pump. Moreover, peristaltic pumps are typically energy efficient, and suitable for use with a wide range of fluids, thus increasing the flexibility of the rotary evaporator for handling a multitude of fluids, and reducing the downtime between cycles. According to a second aspect of the invention, there is provided a control system for a rotary evaporator, said rotary evaporator including a vessel for receiving a mixture comprising a first liquid material and a second material, a heating device configured to heat the vessel for evaporating the first liquid material from the mixture, and a pump arranged and configured to generate a pressure in the vessel, wherein the control system comprises: a controller; and a sensor configured to measure a parameter associated with the pump and to provide a signal to the controller based on said parameter, wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate an output when it is determined that evaporation of the first liquid material has been completed. According to a third aspect of the invention, there is provided a method of controlling a rotary evaporator, said rotary evaporator including a vessel for receiving a mixture comprising a first liquid material and a second material, a heating device configured to heat the vessel for evaporating the first liquid material from the mixture, and a pump arranged and configured to generate a pressure in the vessel, the method comprising the steps of: measuring a parameter associated with the pump using a sensor; providing a signal to a controller based on said parameter; and determining whether evaporation of the first liquid material has been completed based on the signal from the sensor and generating an output when it is determined that evaporation of the first liquid material has been completed. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of the rotary evaporator of the present teachings. DETAILED DESCRIPTION OF EIMBODIMENT(S) Referring to Figure 1, a rotary evaporator is indicated generally at 1. In the illustrated embodiment, the evaporator 1 includes a vessel 2 for receiving a mixture comprising a first liquid material and a second material, a heating device 3 configured to heat the vessel for evaporating the first liquid material from the second material, a pump 4 arranged and configured to reduce the pressure in the vessel to generate a vacuum in the vessel, and a control system 5. In some embodiments, the rotary evaporator 1 may be a fume hood based rotary evaporator, but it should be appreciated that the rotary evaporator 1 may be suitable for use in any setting and may be of any type, for example, the rotary evaporator 1 can be used as a laboratory instrument or in an industrial setting. It should be understood that the control system 5 described is suitable for use with any type of rotary evaporator. The mixture treated in the rotary evaporator is typically in liquid form (i.e. it contains at least one liquid material), but may also contain solid particles suspended in a liquid material or dissolved solids. It should be understood that the mixture can include a plurality of materials with varying properties. For example, the mixture typically contains materials that are heat-sensitive, volatile, or prone to decomposition under high temperatures or atmospheric conditions. Examples of mixtures that can be treated with the rotary evaporator 1 include organic solvents, natural products, essential oils, plant extracts, pharmaceutical compounds, and food extracts. The vessel 2 of the rotary evaporator 1 defines an internal volume so as to be capable of receiving a mixture. In some embodiments, the mixture includes at least a first liquid material and a second material, but any suitable number of liquid materials and / or second materials may be treated in the rotary evaporator 1. The vessel 2 may be any container capable of receiving a mixture and housing the mixture during the evaporation process. In the illustrated embodiment, the vessel 2 is in the form of a round-bottomed flask. The vessel has a conical shape that tapers toward the bottom. This shape of the vessel 2 can allow for efficient heating and evaporation of the mixture therein. The vessel 2 can be of various sizes, ranging from small volumes (e.g. of 50 mL) up to larger volumes (e.g. of 20 L or more). The size of the vessel 2 can be selected based on space requirements and the throughput demand of the evaporator. The vessel 2 is typically made from an optically transparent material to allow operators of the evaporator 1 to observe the evaporation process. In some embodiments the vessel 2 is made of glass. The vessel 2 may be made of a chemically resistant material. It should be appreciated that the vessel 2 may be made of any suitable material. In exemplary embodiments, the vessel 2 includes one or more seals to seal the internal volume of the vessel. The vessel 2 can include an airtight seal. The seal can prevent outside air or moisture from contaminating the mixture in the vessel 1 and allows for a more efficient and controlled evaporation process. In some embodiments, the vessel 2 has an opening and the seal is fitted over the opening. For example, the seal can be provided by a stopper or a joint that is fitted over the opening of the vessel 2. The rotary evaporator 1 includes an inlet for the introduction of the mixture. The inlet can permit the introduction of mixture into the vessel 2. The inlet can be defined by the opening of the vessel 2, i.e. the stopper or joint can be removed to permit the introduction of mixture into the opening. The rotary evaporator 1 is connectable to a mixture reservoir 6, which can contain a volume of the mixture. The mixture reservoir 6 has a volumetric capacity higher than a volumetric capacity of the vessel 2. Put another way, the mixture reservoir 6 can contain more mixture than the vessel 2. In some embodiments, the inlet of the rotary evaporator 1 is connectable to the mixture reservoir 6. In some embodiments, the inlet is defined in the vessel 2. The inlet is connected to the mixture reservoir via inlet pipe 2a. In Figure 1, the inlet pipe 2a extends from the interior of the vessel to the mixture reservoir 6, so as to provide fluid communication between the mixture reservoir 6 and the vessel 2. In Figure 1, an inlet pipe 2a extends from an exterior of the evaporator 1, through an aperture in the evaporator and into an interior of the vessel 2. In this way, the inlet pipe 2a defines a mixture inlet for the introduction of mixture into the vessel 2. It should be understood that any means of transporting mixture into the vessel 2 may be used in place of the inlet pipe 2a. In use, the mixture can be introduced from the mixture reservoir 6 into the vessel 2 via the inlet pipe 2a. In exemplary embodiments, the aperture in the rotary evaporator 1 and / or the vessel 2 is dimensioned so as to receive the inlet pipe 2a in an interference fit. In this way, an airtight seal can be maintained in the evaporator 1. Alternatively, a seal may be placed around the pipe 2a so as to seal against the aperture. The heating device 3 is intended to heat the vessel 2 to evaporate at least one liquid material from the mixture. As an example, a first liquid material vaporises at a lower temperature than the second material. In this way, the first liquid material will become liberated from the second material as it becomes a vapour and rises, thereby separating the two materials. In Figure 1, the heating device 3 is in the form of a bath 7. The bath 7 can contain a material that is heated using a heating element built into the heating device 3. The bath 7 with the material therein is intended receive at least a portion of the vessel 2. The heating element heats the material in the bath 7 which, in turn, provides heat to the vessel 2. Heat applied to the vessel 2 then heats the mixture within the vessel 2 so as to increase the temperature of the mixture. In some embodiments, the fluid in the bath 7 is water or oil. In some embodiments, the heating element is an electric heating element. The provision of a bath 7 can provide a simple heating device 3 that is easy to control. The heating device 3 may alternatively or additionally include other heating means. In some embodiments, the heating device 3 can include an infrared lamp or a heating mantle. Such heating devices 3 may provide fast and efficient heating to the vessel 2. It should be appreciated that the heating device 3 may be any suitable means of heating. The rotary evaporator 1 includes an outlet that facilitates the removal of the first liquid material from the evaporator 1 after evaporation has occurred. In some embodiments, the outlet is in the vessel 2. In some embodiments, the inlet of the vessel 2 can also serve as the outlet. It may be preferable for the outlet to expel the evaporated first material from the evaporator 1 to the environment in vapour form. This may be preferable if the evaporated first material is not of any value, and so any collection of the first material is unrequired. In some embodiments, such as the illustrated embodiment, the rotary evaporator 1 includes a condenser 8. The condenser 8 is in fluid communication with the vessel 2 via the outlet, such that the evaporated first material can move from the vessel 2 to the condenser 8. The condenser 8 is configured to cool the evaporated first material such that the first material condenses back into liquid form. In exemplary embodiments, the condenser is coupled to a receiving flask 9 that receives the condensed first material. As illustrated, the receiving flask 9 can be positioned beneath the condenser 8, such that the condensed liquid falls under gravity into the flask 8. It should be appreciated that the receiving flask 9 can be in any form suitable for collecting liquid from the condenser 8. Condensing the evaporated first material can prevent the loss of a potentially valuable material, and facilitates the re-use of the material. Moreover, the condenser 8 can prevent the release of the first material as a vapour, which could potentially be toxic or have other negative environmental impacts. The cooling of the condenser can be achieved via the provision of coils connected to a cooling system (not shown). The cooling system may be a chiller, a water tap, or any suitable source of coolant. The coils are cooled by the cooling system, and can contact the evaporated first material, decreasing its temperature and causing it to condense. The outlet of the rotary evaporator 1 is connectable to a receptacle, such as a tank 10. The tank 10 can receive the first material separated from the mixture. The tank 10 may be in any suitable form for receiving and containing liquid, e.g. a flask or any form of storage unit. The outlet of the rotary evaporator 1 can be provided in the receiving flask 9. In the illustrated embodiment, the receiving flask 9 is connectable to the tank 10 via outlet pipe 9a. The outlet pipe 9a extends from the interior of the receiving flask 9 to the tank 10, so as to provide fluid communication between the receiving flask 9 and the tank 10. It should be appreciated that the outlet can be provided in any suitable location. In the illustrated embodiment, the outlet pipe 9a extends from an interior of the evaporator 1, through an aperture in the evaporator. The inlet pipe 2a and outlet pipe 9a extend through the same aperture in the illustrated embodiment. It should be understood that any means of transporting the first material out of the evaporator 1 may be used in place of the outlet pipe 9a. In some embodiments, the material may be removed by an operator following completion of the evaporation process (e.g. by removing the receiving flask 9 from the evaporator 1). In use, the evaporated material can be removed from the rotary evaporator 1 via the outlet pipe 9a. The pump 4 is operably coupled to the vessel 2 so as to generate a vacuum therein. The pump can be connected to the vessel by any appropriate means. In Figure 1, a conduit 11 is coupled to the evaporator 1 and the pump 4 so as to operably couple the evaporator 1 and the pump 4. As is illustrated, the conduit 11 of Figure 1 is connected to the condenser 8 such that the pump 4 can generate a vacuum in the condenser 8 and the vessel 2 (i.e. because the vessel 2 is in fluid communication with the condenser 8). Positioning the conduit Ilin such a way can assist in utilising the pump 4 to draw the evaporated first material out of the vessel 2 and into the condenser 8. In alternative embodiments, the pump 4 can be directly connected to the vessel 2 via the conduit 11. The pump 4 is configured to reduce the pressure in the vessel 2. The pump 4 is configured to generate a negative pressure in the vessel 2. The term "negative pressure" is intended to mean a pressure lower than the surrounding atmospheric pressure, i.e. the pressure external to the vessel 2. "Negative pressure" may also be referred to as a vacuum, or below gauge pressure. The reduction of the pressure in the vessel 2 can reduce the boiling temperature of the liquid material in the mixture when located in the vessel 2. Reducing the boiling temperature of the first liquid material causes the first liquid material to evaporate at a lower temperature compared with operating at atmospheric conditions. Therefore, the temperature requirements of the heating device 3 are reduced and so the energy requirements and processing time of the evaporator 1 are reduced (i.e. because the heating device 3 has to heat the mixture to a lower temperature, which can be quicker to obtain). The pump 4 may be any type of pump capable of generating a negative pressure in the evaporator 1. For example, the pump could be an oil-sealed rotary vane pump, a diaphragm pump, or a scroll pump. The pump 4 can be referred to as a vacuum pump in some embodiments. The vessel 2 is configured to be rotatable when the evaporator is in use. In Figure 1, this is achieved via a rotating motor 12. As can be seen, the vessel 2 can be secured to the motor 12. The motor 12 is rotatable such that the vessel 2 is rotated with the motor 12 in use. The motor 12 can be powered by any suitable means. Rotating the vessel 2 can increase the surface area of the vessel 2 exposed to the heating device 3. The motion allows for even and efficient heating of the vessel, which reduces the time required for the evaporation process. Although the evaporator 1 has been described above with reference to numerous components, it shall be appreciated that in alternative embodiments, any combination of these components may be present / omitted from the evaporator 1. The control system 5 is configured to control operation of the rotary evaporator 1 and includes a controller 13 and a sensor 14. The sensor 14 can measure at least one parameter associated with the pump 4 and provide a signal to the controller 13 based on the measurement. In exemplary embodiments, the sensor 14 is configured to continuously measure a parameter associated with the pump 4 and send regular signals to the controller 17 based on this measurement. It should be understood that the sensor 14 can be in the form of multiple sensors that measure various parameters associated with various units of the rotary evaporator, including for example, pressure, temperature, flow of mixture into the evaporator 1, flow of the first liquid material out of the evaporator 1, rotational speed of the vessel 2. The control system 5 can include a memory 15 for storing the signal from the sensor 14. The control system 5 can include a display 16 for displaying various indicators to operators. It shall be appreciated that in alternative embodiments, any combination of these components may be present / omitted from the control system 5. In some embodiments, the control system 5 can control the heating device 3 and the motor 12 so as to control the temperature within the vessel 2 and the rotational speed of the vessel 2. Controlling such parameters can assist the control system 5 in controlling the rate of evaporation of the first material in the vessel. The control system 5 may be configured to control the pump 4. More specifically, the controller 13 can instruct the pump to generate a pressure in the vessel 2. The pump 4 will respond to an instruction from the controller 13 and will attempt to operate so as to generate the pressure. In exemplary embodiments, the signal from the sensor can indicate the response of the pump to instructions from the controller 13. The controller 13 is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor 14. The controller 13 is configured to generate an output when it is determined that evaporation of the first liquid material has been completed. The sensor 14 is configured to measure a parameter associated with the pump 4 and provide a signal to the controller 13 based on the parameter. The controller 13 can then determine whether evaporation of the first liquid has been completed based on at least the signal from the sensor 14. The signal from the sensor can correspond to the measured parameter associated with the pump 4. The means of determining whether evaporation of the first liquid has been completed will be discussed in more detail further below. Utilising a parameter associated with the pump 4 to determine when the evaporation is complete has been found to provide an accurate means of detecting completion of evaporation. Improving the accuracy of such a detection has been found to improve the automation of the evaporation process, preventing energy waste, and thus reducing the cost of using the evaporator. The means of introducing the mixture into the vessel will now be discussed with reference to Figure 1. The controller 13 is configured to instruct the rotary evaporator 1 to draw a predetermined volume of mixture into the vessel 2. In exemplary embodiments, the controller 13 is configured to instruct the rotary evaporator 1 to draw the predetermined volume of mixture from the mixture reservoir 6. The controller 13 is configured to instruct the rotary evaporator 1 to draw the predetermined volume of mixture into the vessel 2 when it is determined that evaporation of the first liquid material has been completed. Put another way, the controller 13 is configured to detect that an evaporation cycle has been completed and, in response, initiate an evaporation cycle. The controller can initiate another evaporation cycle by instructing the evaporator 1 to draw in further mixture for processing in the evaporator 1. The output generated by the controller 13 when the evaporation of the first liquid material has been completed can be provided in the form of such an instruction to the rotary evaporator 1 to draw the predetermined volume of mixture into the vessel 2. In some embodiments, the controller 13 can be configured to initiate an evaporation cycle in response to an input from an operator. For example, the operator may initiate the first evaporation cycle by providing an input to the evaporator 1 (e.g. by pressing a button, or by simply turning the evaporator on). All subsequent initiations may be automated by the controller 13. The configuration of the controller 13 permits the automation of the introduction of mixture (e.g. a predetermined volume of the mixture) into the vessel 2 for treatment in the evaporator 1. As such, the need for an operator to manually introduce a mixture into the vessel 2 can be removed. Removing the requirement of an operator to introduce mixture to the vessel 2 can permit the evaporator 1 to operate to treat large volumes of mixture when no operators are present (e.g. overnight). The predetermined volume can be user inputted into the control system 5. The predetermined volume can be stored in the memory 15. It should be understood that the control of the introduction of mixture may be achieved using various means of flow control. The inlet of the rotary evaporator 1 is connectable to the mixture reservoir 6 via a valve system in the illustrated embodiment. In the Figure, the pipe 2a provides fluid communication between the mixture reservoir 6 and the vessel 2. The pipe 2a includes an inlet valve 17. The inlet valve 17 is moveable between an open position and a closed position. The controller 13 is configured to move the inlet valve 17 between the open and closed positions. The controller 13 is configured to move the inlet valve 17 to the open position when it is determined that evaporation of the first liquid material has been completed. The controller 13 is also configured to move the inlet valve 17 to a closed position when it is determined that the predetermined volume of mixture has been introduced into the vessel 2. The inlet valve 17 has been found to provide a flexible and efficient means of introducing mixture into the vessel 2 when desired, and can be accurately controlled by the controller. This arrangement has been found to allow efficient introduction of mixture into the vessel 2 following the completion of evaporation of the first liquid. Put another way, the downtime between the end of one evaporation cycle and the start of another can be reduced, thus reducing the time required for the evaporator 1 to process the mixture in the mixture reservoir 6. In some embodiments, the inlet valve 17 is a solenoid valve or is coupled to a solenoid arrangement. In this way, the controller 13 can be configured to instruct the solenoid to open the inlet valve 17 at the appropriate moment, i.e. when it is determined that evaporation of the first liquid material has been completed. Utilising a solenoid valve or solenoid arrangement has been found to permit precise and accurate control of the flow of mixture through the pipe 2a. Moreover, solenoids have fast response times to instructions from the controller 13, thus permitting the solenoid to quickly move the valve 17 as required and thus reduce the downtime of the evaporator 1 in between evaporation cycles. However, the inlet valve 17 may be any appropriate valve for controlling flow of the mixture, for example, a butterfly valve, a needle valve, a ball valve, a diaphragm valve, a gate valve, or a globe valve. In some embodiments, a sensor may detect the flowrate of mixture entering the vessel 2 and signal the flowrate to the controller 13. The controller 13 can be configured to determine when the predetermined volume is present in the vessel 2 based on the flowrate signal. It should be appreciated that any suitable means may be implemented to determine when the predetermined volume of mixture has been introduced into the vessel 2 (e.g. via a flowmeter in the pipe 2a). In addition, or as an alternative to the inlet valve 17, the pump 4 can be configured to draw the predetermined volume of mixture into the vessel 2. The controller 13 is configured to instruct the pump 4 to reduce the pressure in the vessel 2 when it is determined that evaporation of the first liquid material has been completed. It is advantageous for the controller 13 to instruct the pump 4 to generate a negative pressure in the vessel 2 in this case. The reduction in pressure encourages flow of the mixture into the vessel 2. In exemplary embodiments, the pump 4 can be instructed to generate a pressure in the vessel 2 that is less than the pressure of the mixture reservoir 6. In this way, the mixture is encouraged to flow from the reservoir 6 to the vessel 2. The utilisation of the pump 4 in such a way can facilitate quick movement of the mixture into the vessel 2, thus minimising downtime between evaporation cycles. The pump 4 can be used in combination with the inlet valve 17 to facilitate effective and efficient control of the introduction of the mixture into the vessel 2. In this way, the controller 13 is configured to instruct both the inlet valve 17 and the pump 4 when it is determined that evaporation of the first liquid material has been completed. The pump 4 is configured to generate an evaporation pressure in the vessel 2. The controller 13 can be configured to instruct the pump 4 to generate the evaporation pressure. In exemplary embodiments, the controller 13 is configured to instruct the pump 4 to generate the evaporation pressure when it is determined that the predetermined volume of mixture has been introduced into the vessel 2. The controller 17 is configured to determine that evaporation of the first liquid material is occurring when the signal from the sensor is substantially constant for a predetermined time. Put another way, the controller 17 is configured to determine the rate of change of the signal from the sensor 14 with respect to time. The controller 17 can then determine that evaporation is occurring in the vessel 2 when the rate of change is approximately zero for a predetermined time. Utilising information regarding the rate of change of the signal can indicate that the parameter associated with the pump 4 is constant. Parameters associated with the pump are generally constant during evaporation because the pump 4 is working to reduce the pressure in the vessel 2 against the increase in pressure typically caused by the evaporation. Before evaporation begins, the pump 4 can reduce pressure in the evaporator 1 with relative ease and so will continue to work to decrease the pressure as instructed. Once evaporation begins, the pump 4 is required to combat the pressure increase from the evaporation of the first liquid material and so the pump 4 will no longer be able to reduce the pressure. As such, the parameter associated with the pump 4 will be substantially constant, and the controller 17 can thereby determine that evaporation is occurring. The means of determining whether evaporation of the first liquid has been completed will now be discussed in more detail with reference to Figure 1. In exemplary embodiments, the controller 13 is configured to request the pump 4 to generate a pressure in the vessel 4 below the evaporation pressure and to monitor the signal from the sensor 14 in response to the request. In exemplary embodiments, the controller 13 is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor 14. The controller 13 can be configured to request the pump 4 to generate the pressure below the evaporation pressure once the controller 13 determines evaporation is occurring. In exemplary embodiments, the controller 13 is configured to request the pump 4 to operate at a pressure 10% less than the evaporation pressure. The pump 4 cannot typically generate a pressure below the evaporation pressure in the vessel 2 while evaporation is occurring. The controller 13 is configured to determine the evaporation of the first liquid is occurring when the pump 4 is unable to generate a pressure in the vessel 2 below the evaporation pressure. Instructing the pump 4 to decrease the pressure further once evaporation is occurring causes the pump 4 to attempt to generate a pressure beyond its operational capabilities. In response to such a request, the pump 4 will exert considerable effort in trying to reach such a low pressure. More specifically, the pump 4 will exert energy in an attempt to both counter the pressure increase from evaporation and to further reduce the pressure as requested. However, decreasing the pressure further is beyond the operational capability of the pump 4 and so the lower pressure cannot be generated by the pump 4 during evaporation. Instead, the pressure in the vessel 2 is maintained at the evaporation pressure. The effort exerted by the pump 4 and / or the pressure in the vessel 2 is reflected in the parameter associated with the pump 4, which is communicated to the controller 13 via the signal from the sensor in 14. Determining that evaporation is ongoing can prevent the controller 13 erroneously attempting to turn the evaporator 1 off, and thus ensures that the evaporator 1 can continue to operate as required. As such, the evaporation of the first material is less likely to be incomplete, thereby improving the purity of the final products. Moreover, the ability of the control system 5 to identify that evaporation is ongoing in the rotary evaporator 1 improves the ability of the control system to automate the process, since the controller can respond more quickly to changes, thus reducing any wasted time, or downtime in the evaporator and therefore reducing the operating cost of using the evaporator. The controller 13 is configured to determine that evaporation of the first liquid material is completed when the pump 4 is able to generate a pressure in the vessel 2 below the evaporation pressure. More specifically, since the pump 4 is instructed to reduce pressure beyond the evaporation pressure, any parameter associated with the pump 4 (and thus the signal from the sensor 14) will indicate a significant effort is being exerted by the pump 4 to both sustain the pressure during the evaporation, but also reduce the pressure further. Once the evaporation process is complete, the pump 4 will no longer be exerting effort against the evaporation of the first liquid material, and so will be able to reduce the pressure with relative ease. The parameter (and thus the signal from the sensor 14) will indicate this change (i.e. reduction of effort) in the pump 4 which will thus allow the controller to detect the end of the evaporation. Put another way, the controller 13 can monitor the signal from the sensor 14 over time. The controller 13 is configured to determine that evaporation of the first liquid material is completed when the signal from the sensor 14 deviates from a previous signal by a deviation of greater than a predetermined value. As discussed above, the parameter associated with the pump, and thus the signal from the sensor, will be generally constant during evaporation. Such is because the pump 4 is exerting significant effort to overcome the pressure increase from the evaporation and to reduce the pressure further. Once the evaporation is complete, the pump 4 no longer exerts such effort and can reduce the pressure in the vessel 2. As such, the parameter associated with the pump 4 will deviate from the constant evaporation pressure, and indicate to the controller 13 that evaporation of the first liquid material is complete. Setting the deviation to be greater than a predetermined value reduces the risk of any small fluctuations in the readings from the sensor 14 triggering the controller 13 to incorrectly determine the evaporation is complete. As such, the reliability of the evaporator 1 is increased, and the quality of the output is improved, since substantially all of the first liquid material is removed from the second before the controller 13 determines the evaporation is complete. Such a configuration of the control system 5 and pump 4 has been found to improve the accuracy of the control system 5 and thus improve the effectiveness of automating the evaporator 1. The parameter associated with the pump 4 can be any parameter that indicates the response of the pump 4 to the instruction from the controller 13. In exemplary embodiments, the parameter measured by the sensor 14 can include the pressure in the vessel 2. Utilising data regarding pressure in the vessel 2 provides an indication as to the effect of the pump 4. Pressure recording has been found to provide an accurate means of determining whether the evaporation of the first liquid is complete, thus increases the reliability of the evaporator and the quality of the separation. In such an embodiment, the sensor 14 can be in the form of a pressure sensor coupled with the vessel 2. It should be understood that any sensor or sensors suitable for determining pressure in the vessel 2 could be utilised. Utilising the pressure in the vessel 2 can assist the controller 13 in determining the status of evaporation in the vessel 2. In particular, while evaporation is ongoing, the pressure signal from the sensor 14 will be constant. When evaporation is complete, the pump 4 can reduce the pressure as instructed. The reduction in pressure will be identified by the controller 13, which will then determine that evaporation is complete. The parameter associated with the pump 4 may be an output characteristic of the pump 4 in some embodiments. The parameter measured by the sensor 14 can include a parameter that is a function of the effort and / or work exerted by the pump 4. In some embodiments, the parameter is a flowrate of fluid through the pump 4. In such an embodiment, the sensor 14 may be in the form a flowmeter. The parameter may be the power consumption of the pump 4. In such an embodiment, the sensor 14 may be in the form of a power meter or a wattmeter. The parameter may be the rotational speed of the pump 4. In such an embodiment, the sensor 14 may be in the form of a tachometer. It should be appreciated that any combination of these parameters may be measured by the sensor 14. In some embodiments, there are a plurality of sensors 14 monitoring various parameters of the pump 4 and signalling the parameters to the controller 13. Measuring one or more output characteristics of the pump 4 provides an indication as to the effort or work exerted by the pump 4 to generate the required pressure in the vessel 2. This has been found to provide a reliable indication to the controller 13 as to the progress of the evaporation. Understanding the effort and / or work exerted by the pump can assist the controller 13 in determining the status of evaporation in the vessel 2. While evaporation is ongoing, the signal from the sensor 14 regarding the effort and / or work of the pump 4 will be substantially constant as the pump 4 operates to generate the lowest pressure in the vessel 2 possible in view of the evaporation which generates pressure. When the evaporation is complete, the pump 4 can reduce the pressure in the vessel 2 as instructed, since the pump 4 no longer needs to work against the evaporation. In this way, the work and / or effort exerted by the pump 4 will reduce. The reduction in work and / or effort exerted by the pump 4 will be communicated to the controller 13 via the signal from the sensor 14. The controller 13 can then be configured to determine that evaporation is complete. In some embodiments, the sensor 14 is configured to measure both the pressure in the rotary evaporator 1 in combination with the flow rate through the pump 4 and / or the power consumption of the pump and / or the rotational speed of the pump, or any other parameter that indicates the performance of the pump 4. The control system 5 as set forth can thus facilitate the effective and accurate automation of operation of the rotary evaporator 1. The means of removing the first liquid material from the evaporator 1 will be discussed with reference to Figure 1. The outlet of the rotary evaporator is connectable to a removal pump 18 in the illustrated embodiment. The removal pump 18 is configured to generate a negative pressure (i.e. a pressure lower than the pressure in the receiving flask 9) so as to draw the first liquid material from the evaporator 1 via the outlet. The removal pump 18 can facilitate quick movement of the first liquid material out of the evaporator 1. Moreover, pumps are versatile and can handle a wide range of fluid types, therefore improving the versatility of the rotary evaporator to treat different types of fluids. The removal pump 18 is configured to draw the first liquid material from the rotary evaporator 1 to the tank 10 in exemplary embodiments, so as to facilitate easy collection of the material. The removal pump 18 is a peristaltic pump in exemplary embodiments. Peristaltic pumps have been found to be ideal for limiting contamination of fluids passing through, since the fluid will not come into contact with any parts of the pump besides a flexible tube. As such, the purity of the material is not adversely impacted by movement through the removal pump 18. Moreover, peristaltic pumps are typically energy efficient, and suitable for use with a wide range of fluids, thus increasing the flexibility of the rotary evaporator 1 for handling a multitude of fluids, and reducing the downtime between cycles. In Figure 1, the outlet of the rotary evaporator 1 is connectable to the tank 10 via the pipe 9a and the removal pump 18 is operably coupled to the pipe 9a. In this way, the removal pump 18 can facilitate movement of the first liquid material from the receiving flask 9 to the tank 10 via the pipe 9a. The controller 13 is configured to instruct the removal pump 18 to draw the first liquid material from the receiving flask 9 when desired. In some embodiments, the removal pump 18 can be continuously operating to draw the first liquid material from the evaporator 1 as it is formed in the receiving flask 9. Alternatively, the controller 13 can be configured to instruct the removal pump 18 to periodically operate so as to remove the first liquid material from the evaporator 1. The control system 5 can include additional sensors in exemplary embodiments to determine when the receiving flask contains a predetermined volume of the evaporated first liquid material, and thereupon instruct the removal pump 18 to draw the fluid therefrom (e.g. to avoid the receiving flask 9 overfilling). In Figure 1, the pump 4 for generating pressure in the vessel 2 and the removal pump 18 are two separate pumps. In alternative embodiments, only one pump may be provided to serve both of these functions. Utilising a single pump to control introduction and removal of materials from the rotary evaporator reduces the equipment requirements of the evaporator and thus reduces the overall cost. In Figure 1, the outlet is coupled to the tank 10 via an outlet valve 19. The outlet valve 19 is located in the pipe 9a between the removal pump 18 and the outlet of the rotary evaporator 1. The outlet valve 19 may be similar to the inlet valve 17 in exemplary embodiments. The outlet valve 19 is moveable between an open and a closed position. The controller 13 is configured to control movement of the valve 18 between the respective positions. In some embodiments, the controller 13 is configured to instruct the valve 19 to be continuously open, so as to promote the constant removal of the first liquid material as it is formed in the receiving flask 9. Alternatively, the controller 13 may instruct the valve to periodically open to remove the first liquid material. The control system 5 can include additional sensors to determine when the receiving flask contains a predetermined volume of the evaporated first liquid material, and thereupon instruct the valve 18 to open. In some embodiments, the outlet valve 19 is a solenoid valve or is coupled to a solenoid arrangement. In this way, the controller 13 can be configured to instruct the solenoid to open the outlet valve 19 so as to remove the first liquid material from the evaporator 1. Although the removal of the first liquid material from the evaporator 1 has been described in relation to a pump and / or valve arrangement, it should be appreciated that any appropriate means may be connectable to the rotary evaporator 1 so as to remove the evaporated solvent therefrom. For example, the removal pump 18 may not be present in some embodiments. Instead, the controller may be configured to instruct pump 4 to pressurise the rotary evaporator, and then instruct the outlet valve 19 to open. In this way, the material will flow from out of the evaporator 1. Alternatively, syringe pumps may be implemented in some embodiments. In some embodiments, the first liquid material may not be removed from the evaporator 1. For example, the receiving flask 9 may be sized to receive a large volume of liquid, such that the receiving flask 9 can collect all of the liquid separated from the mixture reservoir 6. In exemplary embodiments, the controller 13 can be configured to instruct the evaporator 1 to remove of the first liquid material from the evaporator 1 when it is determined that evaporation of the first liquid material has been completed. More specifically, the controller 13 can be configured to instruct the removal pump 18 and the outlet valve 19 to remove the first liquid material from the receiving flask 9a when it is determined that evaporation of the first liquid material has been completed. In this way, the controller 13 will instruct the introduction of the first liquid material into the vessel 2 from the reservoir 6 at the same time as instructing the removal of the evaporated first liquid material from the receiving flask 9a. The controller 13 is configured to determine whether the mixture reservoir 6 is empty, in exemplary embodiments. In response to determining that the mixture reservoir 6 is empty, the controller can turn the rotary evaporator 1 off. Switching the evaporator 1 off once the reservoir 6 is empty prevents the evaporator continuing to operate when there is no mixture left to treat. Such is particularly important when considering the heating device 3 and the pump 4, which would otherwise be providing heat and reducing pressure until an operator turns the evaporator 1 off. As such, a possible hazardous scenario is avoided, as well as avoiding wasted energy as the evaporator 1 continues to needlessly operate. In some embodiments, the mixture reservoir 6 is connectable to a flowmeter or other means for identifying whether fluid is present in the reservoir 6. The flowmeter can provide a signal to the controller 13 which can then determine whether the reservoir 6 is empty (i.e. if the flowmeter reads zero). In some embodiments, the controller 13 can utilise the evaporation cycle time to determine whether the mixture reservoir 6 is empty. The controller 13 can store an evaporation cycle time in the memory 15. The evaporation cycle time can be inputted by an operator (e.g. based on literature data, or based on previous experience). Alternatively, the evaporation cycle time can be determined by the controller 13. Specifically, the controller 13 is configured to instruct the rotary evaporator 1 to draw the predetermined volume of mixture into the vessel 2 and then monitor the time taken to evaporate the first liquid material from the predetermined volume of mixture so as to determine an evaporation cycle time. The controller 13 is configured to turn off the rotary evaporator when the time taken to evaporate the first liquid is less than the evaporation cycle time by a predetermined amount. Put another way, the controller 13 can monitor the time taken to evaporate the first liquid material from a first batch of the mixture. The time taken to evaporate the first liquid material is then stored by the controller 13 in the memory 15. The controller 13 is then configured to monitor the time taken to evaporate the first liquid material from every subsequent batch of the mixture. The controller 13 is configured to compare the evaporation cycle time for each batch with the evaporation cycle time from the first batch stored in the memory 15. The controller 13 can be configured to determine that the mixture reservoir 6 is empty when the evaporation cycle time for a batch is less than the stored evaporation cycle time. In exemplary embodiments, the controller 13 will turn off the rotary evaporator 1 when the evaporation cycle time for a batch is less than the stored evaporation cycle time by a predetermined amount (i.e. to allow for any small fluctuations so as to avoid the evaporator 1 turning off unnecessarily). It should be understood that although the rotary evaporator 1 and control system 5 have been described in relation to separating only a first liquid material from the mixture, the evaporator 1 and control system 5 can also be configured to evaporating more than one liquid material from a mixture. In this way, the mixture may include a third liquid material. The controller 13 can be configured to determine whether evaporation of either the first or third liquid material is completed based on the signal from the sensor 14. In response to the signal, the controller 13 can be configured to instruct the pump 4 and / or heating device 3 to operate to evaporate the other of the first or third liquid material (e.g. increase the temperature and / or reduce the pressure). The controller 13 is then configured to determine whether evaporation of the other of the first or third liquid material has been completed based on the signal from the sensor 14. It can be seen that the evaporator 1 and control system 5 can operate with a multitude of evaporation stages in a single mixture without significant adjustment. As such, the evaporator 1 can be reliably automated to separate more than two components in a mixture without impacting on the quality of the separated materials. As such, the flexibility of the evaporator 1 to handle mixture of different types is improved. An exemplary operation of the rotary evaporator 1 will now be described with reference to Figure 1. An operator can connect the inlet of the rotary evaporator 1 to the mixture reservoir 6 via the inlet valve 17 using a pipe 2a. The operator can connect the outlet of the rotary evaporator 1 to the drum 10 via the outlet valve 19 and the removal pump 18 using a pipe 9a. The operator then switches the rotary evaporator 1 on. From this point, the evaporator 1 can operate without the operator. Turning on the rotary evaporator 1 can instigate the operation of the heating device 3 and the rotating motor 12 such that the vessel 2 is rotated and heated. Alternatively, the controller 13 can be configured to instruct the motor 12 and heating device 3 to begin rotating and heating the vessel 2 at a later stage (e.g. when the mixture has been introduced into the vessel 2). The controller 13 instructs inlet valve 17 to open (e.g. via a solenoid). The controller 13 instructs the pump 4 to generate a negative pressure suitable for drawing the mixture from the mixture reservoir 6 to the vessel 2. The controller 13 can determine that a predetermined volume of mixture has been drawn into the vessel 2, and in response, instruct the inlet valve 17 to move to the closed position. The controller 13 then instructs the pump 4 to reduce the pressure in the vessel 2 further. The controller 13 will monitorthe signal from the sensor 14 so as to identify when evaporation of the first material has begun (e.g. once the pressure in the vessel 2 cannot be reduced any further and so is constant, and / or once the effort exerted by the pump 4 cannot be increased further and so is constant). As the first liquid material evaporates, it is liberated from the mixture and moves into the condenser 8 as a vapour. As the vapour is drawn over the condenser, it is cooled and condensed back into liquid where it is collected in the receiving flask 9. Once the controller 13 has determined that evaporation of the first material is taking place, the controller 13 instructs the pump 4 to generate a lower pressure in the vessel 2 (i.e. to decrease the pressure beyond the evaporation pressure). The controller 13 monitors the signal from the sensor 14 so as to identify when evaporation of the first liquid material is complete (i.e. when substantially all of the first material has been removed from the mixture). The controller 13 identifies that evaporation of the first liquid material is complete once the pressure in the vessel 2 reduces, and / or once the effort exerted by the pump 4 reduces. The controller 13 then instructs the pump 4 to increase the pressure in the vessel 2 (i.e. generating a negative pressure, but higher than previously) and instructs the inlet valve 17 to open. A second batch of mixture is drawn into the vessel 2 from the reservoir 6. Once the predetermined volume of the mixture is in the vessel 2, the controller 13 instructs the inlet valve 17 to move to the closed position. The controller also instructs the outlet valve 19 to move to an open position, and instructs the removal pump 18 to generate a negative pressure so as to remove the first liquid material from the receiving flask 9 to the drum 10 via the pipe 9a. The controller 13 can determine that the first liquid material is removed from the receiving flask 9 and then instruct the outlet valve 19 to move to the closed position and instruct the removal pump 18 to stop generating a negative pressure. At this point, the evaporation cycle can be repeated. It should be understood that the evaporation cycle can be repeated a plurality of times until the mixture reservoir 6 is empty, at which point the controller can turn off the rotary evaporator 1. The operator can then return to the evaporator 1 to find the evaporation complete. The 5 second material will remain in the vessel 2 and the first liquid material will be stored in the tank 10. Although the teachings have been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope as defined in the appended claims.

Claims

1. A rotary evaporator comprising:a vessel for receiving a mixture comprising a first liquid material and a second material;a heating device configured to heat the vessel for evaporating the first liquid material from the second material;a pump arranged and configured to control a pressure in the vessel;a control system configured to control the rotary evaporator, the control system comprising:a controller; anda sensor configured to measure a parameter associated with the pump and to provide a signal to the controller based on said parameter,wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate an output when it is determined that evaporation of the first liquid material has been completed.

2. The rotary evaporator of claim 1, wherein the vessel comprises an inlet connectable to a mixture reservoir, and wherein the controller is configured to instruct the rotary evaporator to draw a predetermined volume of mixture into the vessel from the mixture reservoir when it is determined that evaporation of the first liquid material has been completed.

3. The rotary evaporator of claim 2, wherein the inlet is connectable to the mixture reservoir via an inlet valve moveable between an open position and a closed position, wherein the controller is configured to move the valve to the open position when it is determined that evaporation of the first liquid material has been completed; optionally, wherein the inlet valve is a solenoid valve.

4. The rotary evaporator of claim 2 or claim 3, wherein the controller is configured to instruct the pump to reduce the pressure in the vessel when it is determined that evaporation of the first liquid material has been completed, so as to draw the predetermined volume of mixture into the vessel from the mixture reservoir.

5. The rotary evaporator of any of claims 2 to 4, wherein the controller is configured to determine whether the mixture reservoir is empty and in response thereto turn the rotary evaporator off.

6. The rotary evaporator of any preceding claim, wherein the pump is configured to reduce the pressure in the vessel to an evaporation pressure which is substantially constant during evaporation of the first liquid material.

7. The rotary evaporator of claim 6, wherein the controller is configured to request the pump to generate a pressure in the vessel below the evaporation pressure and to monitor the signal from the sensor in response to said request to determine whether evaporation of the first liquid material has been completed.

8. The rotary evaporator of claim 7, wherein the controller is configured to determine that evaporation of the first liquid material is occurring when the pump is unable to generate a pressure in the vessel below the evaporation pressure.

9. The rotary evaporator of claim 7 or claim 8, wherein the controller is configured to determine that evaporation of the first liquid material is completed when the pump is able to generate a pressure in the vessel below the evaporation pressure.

10. The rotary evaporator of any preceding claim, wherein the parameter comprises the pressure in the vessel.

11. The rotary evaporator of any preceding claim, wherein the parameter comprises at least one of: flow rate of mixture passing through the pump, power consumption of the pump and rotational speed of the pump.12.The rotary evaporator of any preceding claim, wherein the controller is configured to instruct the rotary evaporator to draw a predetermined volume of mixture into the vessel and to monitor the time taken to evaporate the first liquid material from the predetermined volume of mixture so as to determine an evaporation cycle time.13.The rotary evaporator of claim 12, wherein the controller is configured to turn off the rotary evaporator when the time taken to evaporate the first liquid is less than the determined evaporation cycle time by a predetermined amount.14.The rotary evaporator of any preceding claim, wherein the mixture further comprises a third liquid material, and wherein the controller is configured to determine whether evaporation of the third liquid material has been completed based on the signal from the sensor and in response thereto instruct the pumpand / or the heating device to operate so as to evaporate the first liquid material, and wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate the output when it is determined that evaporation of the first liquid material has been completed.15.The rotary evaporator of any preceding claim, wherein the rotary evaporator comprises an outlet for removing the first liquid material from the evaporator after evaporation, wherein the outlet is coupled to a removal pump, the removal pump configured to generate a negative pressure such that the first liquid material is drawn from the evaporator via the outlet; optionally, wherein the removal pump is the pump.

16. The rotary evaporator of claim 15, wherein the outlet is coupled to the removal pump via an outlet valve moveable between an open position and a closed position, wherein the controller is configured to move the valve to the open position so as to remove the first liquid material from the rotary evaporator; optionally, wherein the outlet valve is a solenoid valve.

17. The rotary evaporator of claim 15 or claim 16, wherein the removal pump is a peristaltic pump.

18. A control system for a rotary evaporator, said rotary evaporator including a vessel for receiving a mixture comprising a first liquid material and a second material, a heating device configured to heat the vessel for evaporating the first liquid material from the mixture, and a pump arranged and configured to generate a pressure in the vessel, wherein the control system comprises:a controller; anda sensor configured to measure a parameter associated with the pump and to provide a signal to the controller based on said parameter,wherein the controller is configured to determine whether evaporation of the first liquid material has been completed based on the signal from the sensor and to generate an output when it is determined that evaporation of the first liquid material has been completed.

19. A method of controlling a rotary evaporator, said rotary evaporator including a vessel for receiving a mixture comprising a first liquid material and a second material, a heating device configured to heat the vessel for evaporating the first liquid material from the mixture, and a pump arranged and configured togenerate a pressure in the vessel, the method comprising the steps of: measuring a parameter associated with the pump using a sensor;providing a signal to a controller based on said parameter; anddetermining whether evaporation of the first liquid material has been5 completed based on the signal from the sensor and generating an output when it is determined that evaporation of the first liquid material has been completed.

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