APPARATUS FOR EXTRACTING OIL FROM PLANT MATERIAL.
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- MACH TECHNOLOGIES
- Filing Date
- 2022-08-26
- Publication Date
- 2026-06-12
Smart Images
Figure MX435094B0
Abstract
Description
APPARATUS FOR EXTRACTING OIL FROM PLANT MATERIAL Provisional applications This application claims the benefit of U.S. provisional patent applications 62 / 982,180 filed February 27, 2020; 62 / 982,188 filed February 27, 2020 and 63 / 006,343 filed April 7, 2020, the full disclosure of each of which is incorporated herein by reference. Technical Field This invention relates to the extraction of oil from oil-containing plant material and, more particularly, to an apparatus for extracting said oil using a volatile solvent. Background Several methods and a variety of manually operated apparatus have been developed for extracting vegetable oil from oil-bearing plant material. Some of these methods and manually operated apparatus are disclosed in U.S. Patents 9,687,754, 9,669,328, 9,399,180, and 9,327,210. Typically, an operator must be present to manually operate and cycle the apparatus to carry out the extraction of vegetable oil from the oil-bearing plant material. These apparatus and methods generally utilize a flammable solvent, usually hydrocarbon-based, such as propane, butane, mixtures thereof, ethane, methane, alcohol, and similar substances.Due to the flammable and explosive nature of these hydrocarbon solvents, the fume hood must be used in a Class 1, Division 1 (C1D1) room large enough to accommodate both the hood and the operator when the hood is in use, with the hood at least three feet away from each wall of the room. Therefore, such C1D1 rooms are relatively large and expensive, as they must enclose both the hood and the operator. Therefore, it would be desirable to have an automated apparatus for extracting vegetable oils from oil-containing plant material by extraction methods using a flammable solvent, the apparatus of which would not require to be housed in a separate C1D1 room, would not require an operator to be in a C1D1 room, and would not require an operator to manually cycle, monitor, and operate the extraction apparatus. Synthesis A vegetable oil extraction apparatus may include a solvent tank for receiving a volatile solvent, a plant material container for receiving volatile solvent from the solvent tank, a cooler for cooling volatile solvent to a liquid state in contact with oil-bearing plant material in the material container, a collection vessel for receiving a mixture of volatile solvent and vegetable oil from the material container, a heater for heating at least the volatile solvent in a liquid state in the collection vessel to a gaseous state, a compressor for compressing the volatile solvent gas from the collection vessel to a higher pressure, a heat exchanger configured to receive compressed volatile solvent gas from the compressor and to cool and condense at least part of the compressed solvent gas to a liquid state and return at least the liquid volatile solvent from the heat exchanger to the solvent tank.The apparatus may include a first pressure sensor and a first temperature sensor, each associated with the solvent tank, a second temperature sensor and a second pressure sensor, each associated with the material container, and / or a third temperature sensor and a third pressure sensor, each associated with the collection vessel, and an electronic controller, such as a programmable logic controller configured to receive inputs from the temperature sensors and the pressure sensors and to control the transfer of volatile solvent from the solvent tank to the material container, control the chiller to maintain at least part of the solvent in the material container in a liquid state, control the transfer of a mixture of liquid volatile solvent and vegetable oil to the collection vessel, control the heater to heat at least part of the liquid solvent in the collection vessel to a gaseous state,to control the transfer of at least a portion of the solvent gas from the collection vessel to the compressor, and / or to control the transfer of at least some volatile solvent in liquid form from the heat exchanger to the solvent tank. In some configurations, a solvent level sensor can provide input to the programmable logic controller (PLC) indicating the level of liquid solvent in the solvent tank, material container, or both. In other configurations, a level sensor can provide input to the PLC indicating the level of a liquid mixture of vegetable oil and solvent in the collection container. In some ways, a weight sensor can provide an input to the programmable logic controller indicating the weight of the liquid volatile solvent in the solvent tank. In some configurations, the apparatus may include an input for supplying an inert gas at superatmospheric pressure to the solvent tank. In some configurations, a vacuum may be applied to the material container, the collection vessel, or both. In some forms, the apparatus may include an enclosure that houses the solvent tank, material container, collection vessel, compressor, and heat exchanger. Some forms may include an exhaust system to produce forced airflow through the enclosure and exhaust to the outside. In some forms, the enclosure may include an operator access door that movables to open and closed positions and, when open, is spaced above the top of the material container, and an air duct carried by the operator door to produce airflow over at least the top of the material container and into the air duct and to the outside of the enclosure at a location spaced from the operator door at least when open.In some forms, the material container may carry a movable cover that can be manually moved between a first position that closes the access opening of the material container and a second open position that is spaced apart from and does not overlap the access opening. In some forms, a material cartridge may be fully inserted into the material container when the cover closes the access opening. Some forms may include a fire extinguishing system with at least one outlet nozzle inside and adjacent to the top of the enclosure to discharge a fire extinguishing agent into the enclosure. Brief description of the drawings The following detailed description of certain embodiments and the best mode will be established with reference to the accompanying drawings in which: FIG. 1 is a front perspective view of an extraction appliance with its doors and panels in the closed position; FIG. 2 is a retrospective perspective view of the extraction apparatus of fig. 1 with an open overhead door and an open material container door; FIG. 3 is a front view of the extraction unit with its doors and access panels removed and illustrating various components within its enclosure; FIG. 4 is a side view of the extraction apparatus with its top door and material container door open and its material container in a loading position to receive or remove a cartridge of plant material; FIG. 5 is a complete sectional view of a solvent tank, material container, and collection vessel of the extraction apparatus of FIG. 1; FIG. 6 is a sectional view generally taken on line 6-6 of FIG. 5 and illustrates the material container both in its upright position in use and in its inclined position for loading and unloading plant material; Fig. 7 is an enlarged fragmentary view of the portion in circle 7 of FIG. 6; Fig. 8 is an enlarged view of the portion in circle 8 of Fig. 6; FIG. 9 is a front view of the extraction unit with the doors and access panels removed and illustrates the exhaust airflow within the enclosure when the extraction unit is in use with its doors and access panels closed; FIG. 10 is a perspective view illustrating part of the air exhaust system ducts; FIG. 11 is a side view illustrating the exhaust system airflow when the top door is open and the material container is in its tilted position for removing a cartridge containing plant material from the container; FIG. 12 is a fragmentary isometric view illustrating the exhaust air ducts carried by the upper door; FIG. 13 is a fragmentary sectional view taken at line 13-13 of FIG. 3 illustrating the spray heads of a fire extinguishing system of the extractor apparatus; FIG. 14 is a somewhat schematic isometric view of the fire extinguishing system of the extractor apparatus; FIG. 15 is a rear view of the extraction unit with one access panel removed; FIG. 16 is a schematic diagram of part of the heating and cooling systems of the extractor apparatus; FIG. 17 is a schematic diagram of the sensors, valves, and plumbing arrangements of the extractor apparatus in FIG. 1; and FIG. 18 is a schematic diagram of some of the inputs and outputs of a programmable logic controller of the extractor apparatus of FIG. 1. Detailed description Referring more specifically to the drawings, FIGS. 1-3 illustrate an extraction apparatus 20 for removing and recovering oil from plant material. This vegetable oil can be used for various purposes and products depending on the variety of plant material from which it was extracted, including, but not limited to, perfumes, cosmetics, pharmaceuticals, healthcare, and, more recently, various cannabis-based medical and recreational products. In general, these extraction processes may include, but are not limited to, contacting the plant material with a hydrocarbon solvent to remove the vegetable oil, collecting the solvent and vegetable oil, separating the vegetable oil from the solvent, and recovering the solvent for reuse in further vegetable oil extraction from the plant material.Some steps in these processes utilize heating and / or cooling of the solvent and maintaining it under appropriate superatmospheric pressure during various process steps and for varying periods of time to optimize and maximize the efficiency and / or degree of vegetable oil extraction from the plant material. The optimal time, temperature, and pressure may vary from one plant material to another and / or depending on the specific vegetable oil being extracted. These processes typically use solvents such as propane, butane, alcohol, ethylene, methane mixtures of these solvents, or other similar volatile hydrocarbon solvents that can be changed from a liquid to a gaseous state by heating and cooling them under various pressures. As shown in FIGS. 1-3, a vegetable oil extraction apparatus 20 that is compliant with C1D1 may include a cabinet or enclosure 22 with a hydrocarbon solvent tank 24, a plant material container 26 in which the plant material can come into contact with the solvent, a separation vessel 28 in which the solvent can be separated from the vegetable oil, desirably a sieve 30 for removing moisture, a compressor pump 32 and a heat exchanger 34 (FIG. 15) for recovering the solvent and returning it to the solvent tank 24, a forced air exhaust system 36, and a fire suppression system 38. The extraction apparatus 20 may also include an electronic controller with a memory such as a programmable logic controller (PLC) 42, an operator human-machine interface (HMI) 44 desirably with a display screen 46, and a process and instrumentation diagram (P&ID).The HMI and P&ID allow an operator to input specific data such as times, temperatures, etc., for a given process and monitor the automated implementation of a desired process by the electronic controller or PLC 42, which for at least some functions may include one or more proportional-integral-derivative (PID) loops. The enclosure 22 may have a generally rectangular configuration and a front top door 48 with a handle 50, a material container access door 52, removable front access panels 54, a removable rear access panel 56, and casters 58 to facilitate moving the device from one place to another. As shown in FIG. 5, the solvent tank 24 can be surrounded by an external cooling coil or cooler 60 and an insulating sleeve 62, which is preferably a double-walled, vacuum-sealed thermowell. Other insulating sleeves made of different materials can also be used. Optionally, a cooling coil or cooler 64 can be housed inside the tank and carried by a cover 66 that removably closes and seals an access opening 68 through the top of the tank. The cooling coil(s) can be connected via suitable piping to an inlet manifold cooler 70 and outlet connectors 72 accessible from the outside of the rear of the housing (FIGS. 2 and 15).A cooling unit 74 can be connected to these manifold connectors to circulate a fluid coolant, and preferably a liquid coolant such as a water-antifreeze mixture, through the tank coils. The tank may also have a solvent inlet 76 connected by suitable piping to a manifold solvent inlet connector 78 to supply solvent to the tank and an outlet 80 to deliver solvent from the tank. This tank may also have a nitrogen inlet port 82 connected by suitable piping to a manifold nitrogen inlet connector 84 accessible from the outside of the rear of the enclosure and a solvent return inlet 86.The solvent tank may be made of steel and constructed to withstand sufficient external pressure to keep the vaporizable solvent in liquid form at outside atmospheric temperatures within and around the enclosure with an adequate safety margin. As shown in FIGS. 5 and 6, the plant material container 26 may be surrounded by a cooler coil or chiller 88 and an insulating sleeve 89, which preferably consist of two separate, spaced walls enclosing a vacuum. The material container may have a top access opening 90 that can be closed and sealed by an easily removable cover 92. In its closed position, the cover can be securely fastened to the container by a series of circumferentially spaced threaded fasteners 94 carried by a flange 96 attached to the container. The cover 92 can be connected to the container by a suitable hinge 98 to facilitate manual opening and closing. When the cover is open, a material carrier cartridge 100 can typically be inserted axially into or removed from the container.The cartridge may have an open top 102 with a strap handle 103 and adjacent to the other end a removable filter assembly 104 that can retain plant material in the cartridge, admit solvent into the cartridge, and allow a mixture of solvent and extracted plant oil to flow out of the cartridge and into the container 26 and through an outlet 106 adjacent to the bottom of the container. The container also has a solvent inlet 108, preferably adjacent to the bottom of the container. To facilitate the insertion and removal of the material cartridge 100 from the container, it can be mounted in the enclosure 22 to be movable, as shown in FIG. 6, from a vertical position fully inside the enclosure to an outwardly tilted position in which the top of the container and its access opening 90 extend outwards from the front of the enclosure and desirably underlie the open top door 48. As shown in FIGS. 6 and 7, the container can be movably mounted in the enclosure by means of a transversely extending sleeve 110 that is fixed by brackets to the container and rotatably received on a shaft 112 fixed by brackets to a support rail 114 of the enclosure.The container can be moved between its upright and inclined positions by an air cylinder 116 with a piston rod 118 pivotally connected to a bracket 120 fixed to the container and adjacent to the other end the cylinder can be pivotally connected to a bracket 122 attached to a bracket 124 fixed to the rail 114. As shown in FIGS. 6 and 8, the material container 26 can be releasably held in its upright position within the cabinet 22 by a locking mechanism 126 carried by a frame member of the housing 128 and actuated by a pneumatic cylinder 130 with a piston rod 132 pivotally connected to the locking mechanism and adjacent to the other end, the cylinder housing can be pivotally attached to a bracket 134 carried by a frame member 136 of the enclosure. Container 26 may have a purge port 138 and a vacuum port 140, desirably adjacent to the top of the container. As shown in FIG. 5, the collection vessel 28 may be surrounded by a heating coil 142 enclosed by an insulating sleeve 144, preferably in the form of two separate, spaced walls enclosing a vacuum. This vessel may have a solvent and oil mixture inlet 146, a gaseous solvent outlet 148, and an access opening 150 with a removable cover 152, each desirably adjacent to the top of the vessel, and a liquid oil outlet 154 adjacent to its bottom. Through suitable conduits with solenoid flow control valves, the heater coil 142 may be connected to the collector inlet and outlet connectors 156 and 158 accessible from outside the enclosure.A liquid solvent in the collection vessel can be heated to a gaseous state by means of a heater unit 160 connected to the collector inlet 156 and outlet 158 and by circulating a heated fluid, which is desirably a liquid, through the heater coil 142. For the recovery and reuse of the gaseous solvent from the collection vessel 28, it is desirable that it be passed through a sieve 30 to remove moisture (which generally comes from the plant material), such as a molecular sieve with sieve beads 3A and / or 4I. A heater coil 164 can be in heat transfer relationship with the sieve 30 and connected to the collector connectors 156 and 158 so that, in use, the solvent passing through the sieve remains in a gaseous state. The gaseous solvent from the sieve can be compressed, for example, by the compressor or pump 32 and supplied to the heat exchanger 34 to condense it into a liquid state, and then the condensed liquid solvent can be returned to the solvent tank 24.The heat exchanger 34 can be of conventional construction with condensing coils, shells and tubes, or a plate heat exchanger in which the gaseous solvent is condensed to its liquid state by a coolant such as a liquid refrigerant circulating through the heat exchanger, as by the cooling unit 74. If all the gaseous solvent is not condensed to a liquid state by the heat exchanger, any remaining gaseous portion can also be transferred to the solvent tank in which the pressure will increase and condense the remaining gaseous solvent into a liquid state. During the operation of the extractor apparatus 20, to create a subatmospheric pressure within the enclosure 22 and in the event of any solvent leakage in the system, to prevent any accumulation of flammable solvent gases within the enclosure, the exhaust system 36 continuously moves air through and across the interior of the enclosure as indicated by arrows 170 in FIG. 9. This exhaust system may have within the enclosure and desirably along one side wall an inlet air duct 172 communicating with an air inlet opening 174 to the outside of the enclosure and having a plurality of air outlets or slots 176 through which air can flow into the enclosure, and on the other side wall an outlet air duct 178 communicating with an explosion-proof exhaust fan 180 preferably disposed outside the enclosure.The exhaust air duct 178 may have a series of ventilation grilles, such as slots 182, through which air can flow into the duct when the exhaust fan is operating. The exhaust fan may communicate with the exhaust duct via a suitable hose or pipe 184 as shown in FIG. 2. As shown in FIGS. 10-12, when the top door is open, such as for an operator opening the cover 92 of the material container 26 for the removal or insertion of a material cartridge 100, the lower part of the top door also carries a duct 186 that communicates with the exhaust fan and has a series of vents or slots 188 to ensure that residual solvent gases are also evacuated through the exhaust fan 180 and thus do not enter the atmosphere surrounding the exterior of the enclosure. This duct can be connected by a flexible hose 190 to the outlet duct 178 and thus to the exhaust fan. Desirably, when the top door 48 is open, the exhaust fan flow rate can be increased to ensure that any gaseous solvent does not escape into the atmosphere surrounding the exterior of the housing.The extractor outlet 192 may be channeled to the outside of a building in which the extractor apparatus 20 is used to prevent the accumulation of any flammable gaseous solvent inside the building or room in which the extractor apparatus is operated or used. As shown in Figures 13 and 14, the enclosure 22 may have a fire suppression system 38 that automatically detects a fire and discharges a fire extinguishing agent into the enclosure. This system may have spray heads 194 within the housing, connected by suitable conventional plumbing 196 to a pressurized container 198 containing a fire extinguishing agent. As shown in Figure 2, this container is conveniently mounted outside the enclosure to facilitate monitoring and, if necessary, refilling and / or replacement with a freshly charged and pressurized container. This fire suppression system may also have detection tubes 200 within the enclosure that communicate with a normally closed discharge valve 202 connected to the container.The detection tubes are configured so that when they detect sufficient heat (typically produced by a fire), they rupture, resulting in a drop in over-atmospheric pressure within the tubes. This activates valve 202 to discharge a fire extinguishing agent through spray heads 194 into the enclosure. The fire extinguishing agent may be a Class B agent, typically dry chemical powder, or a film-forming foam. Ideally, this fire extinguishing agent may be a dry chemical or multipurpose dry chemical, such as ammonium phosphate, or a halogenated agent such as Halon 1301 or 1211. Many alternative fire extinguishing systems are known to qualified personnel and may be used, including, but not limited to, a highly pressurized carbon dioxide system. The cooling unit 74 can, through appropriate plumbing and control valves, circulate a fluid refrigerant, and desirably a liquid refrigerant, such as a mixture of water and antifreeze with rust inhibitors, through the cooling coils of the solvent tank 24, the material container 26, and the heat exchanger 34. The chiller unit can circulate a liquid refrigerant that is generally in the range of approximately -90° to -40° C. The chiller unit can be a commercially available refrigeration unit or other chillers known to persons of ordinary skill in the art and can desirably be disposed of outside enclosure 22 and connected via suitable conduits to the refrigerant inlet and outlet connectors 70 and 72 carried by the manifold and accessible from outside the enclosure.Typically, solenoid-operated valves can control the flow or flow rate and cycling of the coolant to the solvent tank, material container, and heat exchanger and can be actuated, cycled, and controlled by the electronic controller or PLC 42. The heater unit 160 can supply a heated fluid, preferably a heated liquid such as a mixture of hot water and antifreeze or another suitable liquid, to the coil 142 of the collector vessel 28 and the coil 164 of the sieve 34 through connectors 156 and 158 and their associated plumbing and solenoid control valves. Suitable forced-circulation liquid heater units are commercially available and familiar to persons of ordinary skill in the art. The heated fluid supplied to the heating coils of the collector vessel and sieve can generally be at a temperature in the range of 100 to 160°F. Alternatively, the collector vessel and sieve can be heated by electric heaters in thermal heat transfer relationship with or within the collector vessel and sieve, respectively. As shown schematically in FIG. 17, for automated process control carried out by the extraction apparatus, several components can be connected and linked together via suitable solenoid control valves that can be actuated, cycled, and controlled by the electronic controller or PLC 42. The solvent tank 24 can be connected via the manifold connector 84 to a source of compressed nitrogen gas through a suitable pipe with a solenoid-operated flow control valve 204 with open and closed states, which is desirably in series with a downstream manual shut-off valve 206. Compressed nitrogen gas can be supplied to the solvent tank if and as required to force the liquid solvent from the tank to the material container.The solvent tank inlet 76 can be connected via suitable plumbing with a solenoid control valve 208 with open and closed states to the manifold fill port 78 and, ideally, with a downstream manual shut-off valve 210. The solvent tank outlet 80 can be connected to the material container inlet 212 26 via suitable plumbing, including a movable solenoid-operated control valve 214 for open and closed states and, ideally, an upstream manual shut-off valve 215. To facilitate automatic cycling and control of valves 204, 208, and 214 by the PLC, a temperature sensor 216, a pressure sensor 217, and a solvent liquid level sensor 218 can be operatively associated with the solvent tank 24 to provide inputs to the PLC. The solvent tank may also have a 220 weight sensor to measure the weight or amount of liquid solvent in the tank. The material container 26 can be connected to a manifold purge connector 224 via suitable piping through a solenoid-operated control valve 226 with open and closed states. The material container can also be connected to a manifold vacuum port 228 via suitable piping with a solenoid-operated control valve 230 with open and closed states. The material container outlet 232 can be connected to a collection vessel inlet 146 of the collection vessel 28 via suitable piping, including a solenoid-operated flow control valve 234 with open and closed states. These valves can be cycled and controlled by the PLC 42. To facilitate automatic control by the PLC, a temperature sensor 236, a pressure sensor 238, and a solvent level sensor 240 can be operationally associated with the material container to provide inputs to the PLC. The collection vessel 28 can also be connected to the vacuum connector 228 of the collector via suitable plumbing, including a movable solenoid-operated control valve 242 for open and closed states, cycled and controlled by the PLC. To facilitate automatic operation, a temperature sensor 244, a pressure sensor 246, and a liquid level sensor 248 can be associated with the collection vessel to provide inputs to the PLC. The vegetable oil outlet 154 of the collection vessel can be connected to a manual valve 250 for open and closed states by the operator or conveniently connected to an outlet connector (not shown) accessible from outside the housing via suitable piping, including a movable solenoid-operated flow control valve 252 for open and closed states, controlled by the PLC and the operator via the HMI interface. Gaseous solvent can flow from the outlet of the collection vessel 148 to an inlet 256 of the sieve 30 through suitable piping, including a solenoid-operated flow control valve 258 that moves between open and closed positions. The sieve can have an associated inlet pressure sensor 260 and an outlet pressure sensor 262 that can provide inputs to the PLC. A sieve outlet 264 for gaseous solvent can be connected to the inlet 266 of the compressor or to the pump 32 through suitable piping, including a solenoid-operated control valve 268 that moves between open and closed positions.The compressor or pump outlet 270 can supply compressed gaseous solvent at a higher pressure to a gaseous fluid inlet 272 of the heat exchanger 34 through suitable piping, including a flow control valve 274 movable to open and closed states. If desired, this valve can also be configured to provide a variety of different flow rates between its fully open and fully closed states. An outlet 276 of the heat exchanger, containing at least predominantly, if not exclusively, condensed liquid solvent, can be returned to the solvent tank 24 through suitable piping, including a solenoid-operated flow control valve 278 movable to open and closed states, and desirably a manual flow control valve 282 downstream of this valve. Each of these solenoid valves can be cycled and controlled by the PLC. As stated above, the heat exchanger cooling coil is also connected to the manifold inlet and outlet connectors 70 and 72 via suitable plumbing conduits and, if desired, the inlet can include a solenoid-operated flow control valve movable to open and closed states and, if desired, to various flow states to further facilitate automatic operation by the PLC. As shown schematically in FIG. 18, each of the temperature, pressure, and level sensors and the weight sensor are electrically connected to an input of the PLC, and each of the solenoid-operated valves is connected to an output of the PLC, typically through a controller to change the valve state for automatic control of the particular extraction process carried out by the PLC. The HMI 44 is electrically connected to the PLC 42 to allow the operator of the extractor 20 to input various times, temperatures, and other variables to execute a particular extraction process. Typically, this HMI will also display, in a way visible to the operator, the implementation and status of various steps of the specific process being carried out automatically by the extractor through the appropriate software and any firmware running on the PLC to control the various solenoid valves in response to the data entered by the operator and any necessary or desired inputs from the appropriate temperature, pressure, level, and weight sensors.To prepare for an operating cycle of the extractor 20, an operator can load plant material into the cartridge 100 and insert the cartridge into the open end 90 of the inclined material container 26. The operator then manually closes and seals the container cover 92 with the cartridge fully inside. Next, the operator can move the material container to its upright position, fully inside the enclosure, and close the top door 48 and the container door 52. If desired, proximity sensors or switches can be associated with the top door and the container door to indicate whether they are closed and to prevent the start of an automated process unless and until they are closed. After the operator has entered the data for time, temperature, etc.To initiate a specific desired process, the process can be started by pressing or tapping a start icon on the operator's HMI, causing the extraction unit to automatically take over and execute the extraction process. Depending on the data entered by the operator, the PLC can apply a vacuum to the material container and the collection vessel (and, if desired, through the collection vessel to the sieve, at least the compressor inlet side, and, depending on its design, to the heat exchanger) to substantially remove all oxygen from the system, thus preventing any potentially combustible oxygen-solvent mixture from being present in the unit. Typically, the PLC would monitor and verify the solvent pressure and temperature in the solvent tank to ensure it is at the desired temperature for supplying liquid solvent to the material container.If necessary, the PLC will control the chiller unit to reach this temperature. Optionally, the PLC can also be programmed to use the input from weight sensor 220 to determine if the solvent tank 24 contains sufficient liquid solvent to run the entire process. When the solvent in the tank reaches this desired temperature, the PLC will open and control valve 214 to transfer the liquid solvent to the material container 26 to a desired level, which can be detected by its associated level sensor 240. When this level is reached, the PLC will initiate the closing of this solvent flow control valve. From then on, the plant material in the material container will be immersed in the liquid solvent for a period of time (Ti) entered by the operator for the specific process the extraction apparatus will run.When this time period is complete, the PLC will open control valve 234 to transfer the liquid solvent and the extracted vegetable oil mixture to the collection vessel 28, and then, upon completion of this transfer, will close this valve. If desired, for a given process, another quantity of liquid solvent can be transferred from the solvent tank to the material vessel to further contact and / or soak the plant material in it for a second time period (T2) to obtain an additional mixture of vegetable oil and solvent. When this second time period (T2) expires, the PLC will open solenoid valve 234 to transfer this additional mixture of solvent and vegetable oil to the collection vessel 28 and then close this valve. Typically, this second time period (T2) is substantially shorter than the first time period (Ti). Next, the PLC normally starts heating the collection vessel 28 and the sieve 30, turns on the compressor pump 32, and starts the flow of refrigerant through the heat exchanger 34. The PLC also opens valves 258, 268, 274 and 278 to allow the flow of gaseous solvent from the collection vessel to and through the sieve, to the compressor pump 32, and the compressed solvent gas through the heat exchanger 34, where at least most, if not all, of the solvent gas is condensed to a liquid state and returned to the solvent tank 24. In the collection vessel, the liquid solvent is heated sufficiently to become a gaseous state and thus separate from the vegetable oil that collects at the bottom of the collection vessel.The heating time (T3) for the collection vessel 28 and sieve 30, the operation of compressor 38, and the circulation of refrigerant through heat exchanger 34 can be initially programmed by an operator who inputs this time via the HMI to the PLC. Alternatively, with appropriate software, the PLC can monitor the temperature, pressure, and liquid level in the collection vessel to determine a suitable time period T3 to ensure that essentially all the liquid solvent in the collection vessel is converted to a gaseous state and transferred from the vessel. After the T3 time period is complete, the PLC can stop the heating of the collection vessel 28 and sieve 30, shut down compressor 32, stop the circulation of refrigerant through heat exchanger 34, and close valves 258, 268, 274, and 278.From then on, the vegetable oil can be removed from the collection vessel 28, typically for further processing. The vegetable oil can be extracted through a lead drain valve at the bottom of the collection vessel, which is movable to open and closed positions. This drain valve can be a manual drain valve 250 that an operator opens and closes manually when it is desired to remove the vegetable oil from the collection vessel, or a solenoid-operated drain valve 252 controlled by the PLC and opened and closed by an operator via the HMI.If desired, once the time period T3 has elapsed and before removing the vegetable oil from the collection container, valve 242 may be opened to provide a vacuum to the collection container for a short period of time to remove any gaseous solvent remaining in the collection container and then closed and allow the pressure inside the collection container to return to atmospheric pressure or, if desired, to a relatively low external pressure, to increase the flow rate of vegetable oil out of the collection container when the drain valve is open. With the appropriate software, the PLC can monitor the temperature, solvent level, and pressure within solvent tank 24, material container 26, and collection vessel 28, as well as the inlet and outlet pressures of sieve 30, throughout the entire process. It can then make necessary adjustments to the various temperatures, pressures, and / or liquid levels to accelerate and improve process efficiency. The PLC can also monitor the extraction apparatus housing via an appropriate sensor to detect hydrocarbon solvent leaks or other harmful effects. If any are detected, the PLC will close all solenoid valves, shut down the process, and maximize the cubic foot-per-minute flow rate of the exhaust fan 5 to prevent a potential fire or explosive condition within the enclosure.If desired, the PLC can record process data for each batch of plant material processed by the extraction apparatus 20 so that an operator can view the exact conditions in each of the solvent tanks, 10 material containers, and collection receptacles that occurred throughout the entire extraction process. If desired, a single operator can run a plurality of these extractor devices 22, such as 4-6 devices, since each device 15 automatically carries out an extraction process and only requires an operator to load plant material into the material container and, after the extraction of the vegetable oil, remove the material container, and enter a limited amount of data for a device to automatically run a specific process and, 20 if desired, manually remove the vegetable oil from the collection container. While the form of the extraction apparatus disclosed herein constitutes the currently preferred embodiment, many other embodiments are possible. It is not intended herein to mention all possible equivalent forms, ramifications, or advantages of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.
Claims
1. A vegetable oil extraction apparatus comprising: a solvent tank configured to receive a volatile solvent; a vegetable material container connected via a first movable valve to the solvent tank to receive at least some of the solvent; a cooler configured to cool the volatile solvent in the vegetable material container to maintain at least some of the volatile solvent in a liquid state in contact with the oil-bearing vegetable material in the vegetable material container; a collection vessel connected via a second movable valve to the material container to receive at least some of a mixture of volatile solvent and vegetable oil from the material container; a heater configured to heat at least some of the volatile solvent from a liquid state in the collection vessel to a gaseous state;a compressor configured to receive, through a third movable valve to open and close states, at least some volatile solvent gas from the collection vessel and to compress at least some of the volatile solvent gas to a higher pressure; a heat exchanger configured to receive at least some compressed volatile solvent gas from the compressor and to cool and condense at least some of the compressed volatile solvent gas to a liquid state; and the heat exchanger connected, through a fourth movable valve to open and closed states, to return at least some of the liquid volatile solvent from the heat exchanger to the solvent tank;a first pressure sensor and a first temperature sensor, each associated with the solvent tank, a second temperature sensor and a second pressure sensor, each associated with the material container, and a third temperature sensor and a third pressure sensor, each associated with the collection container;and a programmable electronic controller configured to receive inputs from the temperature sensors and the pressure sensors and to control the first valve to transfer volatile solvent from the solvent tank to the material container, to control the cooler to maintain at least part of the solvent in the material container in a liquid state, to control the second valve to transfer a mixture of liquid volatile solvent and vegetable oil to the collection vessel, to control the heater to heat at least part of the liquid solvent in the collection vessel to a gaseous state, to control the third valve to transfer at least part of the solvent gas from the collection vessel to the compressor, and to control the fourth valve to transfer at least the volatile solvent in a liquid state from the heat exchanger to the solvent tank.
2. The apparatus of claim 1 characterized in that the volatile solvent is a hydrocarbon solvent.
3. The apparatus of claim 1 characterized in that it also comprises a solvent tank inlet connected through a fifth valve movable to open and closed states by the programmable logic controller to supply an inert gas at a superatmospheric pressure to the solvent tank.
4. The apparatus of claim 1 characterized in that it also comprises a purge valve movable to open and closed states by the programmable logic controller and which communicates with the material container or the collection container or both.
5. The apparatus of claim 1 characterized in that it also comprises a valve movable to open and closed states by the programmable logic controller and configured when open to communicate a vacuum source with the material container or the collection vessel or both.
6. The apparatus of claim 1 characterized in that it also comprises a movable valve for opening and closing positions by the programmable logic controller and which communicates with the solvent tank and operable to control a supply of volatile solvent to the solvent tank.
7. The apparatus of claim 1, characterized in that it also comprises a weight sensor associated with the solvent tank to provide an input to the programmable logic controller indicative of the weight of the liquid volatile solvent in the solvent tank.
8. The apparatus of claim 1 characterized in that it also comprises an enclosure that houses the solvent tank, the material container, the collection vessel, the compressor, and the heat exchanger.
9. The apparatus of claim 8 characterized in that it also comprises an exhaust system configured to produce a forced airflow through the enclosure and out to the outside of the enclosure.
10. The apparatus of claim 9 characterized in that the enclosure 5 also comprises an operator access door movable to closed and open positions and, when open, spaced above a top portion of the material container, and an air duct carried by the operator door and configured to produce airflow over at least the top portion of the material container 10 and into the air duct and out of the enclosure at a location spaced from the operator door at least when open.
11. The apparatus of claim 10 characterized in that the 15 material container is movably mounted in the enclosure and is configured to be movable between a first position completely inside the enclosure with the operator door closed, and with the operator door open to a second position in which an upper end of the material container is disposed at least partly 20 below and spaced below the open door and at least part of the conduits carried by the door.
12. The apparatus of claim 8 characterized in that it also comprises a cover movably carried by the material container so that it can be manually moved between a first position that closes the access opening of the material container and a second open position spaced apart from, but not over, the access opening.
13. The apparatus of claim 1 characterized in that it also comprises a solvent level sensor associated with the solvent tank and configured to provide an input to the programmable logic controller indicating the level of liquid solvent in the solvent tank.
14. The apparatus of claim 1 characterized in that it also comprises a level sensor associated with the material container and configured to provide an input to the programmable logic controller indicating the level of solvent in the liquid state in the material container.
15. The apparatus of claim 1 characterized in that it also comprises a level sensor operatively associated with the collection container and configured to provide an input to the programmable logic controller indicating the level of a mixture of vegetable oil and solvent in liquid state in the collection container.
16. The apparatus of claim 8 characterized in that it also comprises a fire extinguishing system with at least one outlet nozzle within and adjacent to the top of the enclosure and configured to discharge a fire extinguishing agent into the interior of the enclosure.
17. The apparatus of claim 1 characterized in that it also comprises an access opening adjacent to the upper end of the material container, a removable cover configured to close the access opening, and a material cartridge configured to be inserted through the access opening into the material container and which can be fully received inside the material container when the cover closes the access opening.
18. The apparatus of claim 1 characterized in that it also comprises a sieve and a heater operatively associated with the sieve and configured to heat solvent in the sieve.
19. The apparatus of claim 8, characterized in that it also comprises an operator human-machine interface accessible from outside the enclosure by an operator to input data into the programmable logic controller.
20. The apparatus of claim 8, characterized in that it also comprises a human-machine interface accessible from outside the enclosure and configured to allow the operator to input data into the programmable logic controller and a display screen configured to show a process and instrumentation diagram of at least part of the process carried out by the extraction apparatus.