Apparatus for extracting oil from plant material

A plant oil extraction apparatus may include a volatile solvent tank, an oil bearing plant material container for receiving at least some of the volatile solvent, a chiller for cooling volatile solvent to a liquid state in contact with the oil bearing plant material, a vessel for collecting at least some of the mixture of volatile solvent and plant material, a heater for heating at least liquid state volatile solvent to a gas state, a compressor for compressing volatile solvent gas to a higher pressure, and a heat exchanger to cool and condense at least part of the compressed solvent gas to a liquid state and to return at least part of the condensed liquid volatile solvent to the solvent tank. The cycling of the apparatus may at least in part be controlled by an electronic controller and a human machine interface may be used by an operator to input data to the electronic controller.

TECHNICAL FIELD

This invention relates to the extracting of oil from oil bearing plant material and more particularly to an apparatus for extracting such oil using a volatile solvent.

BACKGROUND

Various methods and a variety of manually operable apparatus have been developed for extracting plant oil from oil bearing plant material. Some methods and manual apparatus for doing so are disclosed in U.S. Pat. Nos. 9,687,754; 9,669,328; 9,399,180; and 9,327,210. Usually, an operator needs to be present to manually operate and cycle the apparatus to carry out a process of extracting plant oil from oil bearing plant material. Typically, these apparatus and methods use a flammable usually hydrocarbon-based solvent such as propane, butane, mixtures thereof, ethane, methane, alcohol, and the like. Due to the flammable and explosive nature of these hydrocarbon solvents the extraction apparatus needs to be used in a Class 1, Division 1 (C1D1) room large enough to accommodate both the apparatus and the operator when using the apparatus with the apparatus being at least three feet away from every wall of the room. Thus, such C1D1 rooms are relatively large and expensive since they must enclose both the apparatus and the operator.

Therefore, it would be desirable to have an automated apparatus for extracting plant oils from oil bearing plant material by methods of extraction using a flammable solvent which apparatus did not require being housed in a separate C1D1 room, did not require an operator to be in a C1D1 room and did not require an operator to manually cycle, monitor and operate the extraction apparatus.

SUMMARY

A plant 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 chiller 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 plant oil from the material container, a heater for heating at least liquid state volatile solvent in the collection vessel to a gas state, a compressor for compressing 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 to 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 transfer of volatile solvent from the solvent tank to the material container, to control the chiller to maintain at least part of the solvent in the material container in a liquid state, to control transfer of a mixture of liquid volatile solvent and plant oil to the collection vessel, to control the heater to heat at least part of the liquid solvent in the collection vessel to a gas state, to control transfer of at least part of the solvent gas from the collection vessel to the compressor, and/or to control the transfer of at least some volatile solvent in the liquid state from the heat exchanger to the solvent tank.

In some forms a solvent level sensor may provide an input to the programmable logic controller indicating the level of solvent in a liquid state in the solvent tank or in the material container or both. In some forms a level sensor may provide an input to the programmable logic controller indicating the level of a mixture of plant oil and solvent in a liquid state in the collection vessel.

In some form a weight sensor may provide an input to the programmable logic controller indicative of the weight of liquid volatile solvent in the solvent tank. In some forms the apparatus may include an inlet to supply an inert gas at a superatmospheric pressure to the solvent tank. In some forms a vacuum may be applied to the material container or the collection vessel or both.

In some forms the apparatus may include an enclosure enclosing the solvent tank, material container, collection vessel, compressor, and heat exchanger. Some forms may include an exhaust system for producing a forced air flow through the enclosure and exhausting to the exterior of the enclosure. In some forms the enclosure may include an operator access door movable to closed and open positions and when open spaced above an upper portion of the material container, and an air duct carried by the operator door for producing air flow over at least the upper portion of the material container and into the air duct and to the exterior of the enclosure at a location spaced from the operator door at least when it is open. In some forms a cover may be movably carried by the material container so that it can be manually moved between a first position closing the access opening of the material container and a second open position spaced from and not overlying the access opening. In some forms a material cartridge may be completely received within the material container when the cover closes the access opening.

Some forms may include a fire suppression system with at least one outlet nozzle within and adjacent the top of the enclosure for discharging a fire suppression agent into the interior of the enclosure.

DETAILED DESCRIPTION

Referring in more detail to the drawingFIGS.1-3illustrate an extraction apparatus20for removing and recovering oil from plant material which plant oil may be used for various purposes and products depending on the variety of plant material from which it was extracted such as including without limitation perfumes, cosmetics, pharmaceuticals, healthcare, and more recently various medical and recreationalcannabis-based products. In general, these extraction processes may include without limitation contacting the plant material with a hydrocarbon solvent to remove plant oil from the plant material, collecting the solvent and plant oil, separating the plant oil from the solvent, and recovering the solvent for reuse in extracting plant oil from plant material. Some of the steps of these processes utilize heating and/or cooling of the solvent and maintaining the solvent under appropriate superatmospheric pressure during various steps of the processes and for varying periods of time to try to optimize and maximize the efficiency and/or the extent of extraction of plant oil from the plant material. The optimum time, temperature, and pressure may vary from one plant material to another and/or the particular plant oil it is desired to extract from a given plant material. Typically, these processes may use solvents such as propane, butane, alcohol, ethylene, methane mixtures thereof or other similar volatile hydrocarbon solvents which may be changed from liquid to gaseous states by heating and cooling thereof under various pressures.

As shown inFIGS.1-3, a plant oil extraction apparatus20which is C1D1 compliant may include a cabinet or enclosure22with a hydrocarbon solvent tank24, a plant material container26in which plant material may be contacted with the solvent, a separation vessel28in which the solvent may be separated from the plant oil, desirably a sieve30to remove moisture, a compressor pump32and heat exchanger34(FIG.15) for recovering the solvent and returning it to the solvent tank24, a forced air exhaust system36, and a fire suppression system38. The extraction apparatus20may also include an electronic controller with a memory such as a programmable logic controller (PLC)42, an operator human machine interface (HMI)44desirably with a display screen46and a process and instrumentation diagram (P&ID). The HMI and P&ID enables an operator to enter specific data such as times, temperatures, etcetera for a given process and to monitor the automated implementation of a desired process by the electronic controller or PLC42which for at least some functions may include one or more proportional—integral—derivative loops (PID). The enclosure22may have a generally rectangular configuration and a front overhead door48with a handle50, a material container access door52removable access front panels54, a removable access back panel56, and casters58to facilitate movement of the apparatus from one location to another.

As shown inFIG.5, the solvent tank24may be encircled by an exterior cooling or chiller coil60and an insulator sleeve62which desirably may be a thermos double wall enclosing a vacuum. Other insulative sleeves of other materials may also be used. Optionally, a cooling or chiller coil64may be received inside the tank and may be carried by a cover66removably closing and sealing an access opening68through the top of the tank. The cooling coil or coils may be connected by suitable piping to a manifold chiller inlet70and outlet72connectors accessible from outside of the back of the enclosure (FIGS.2and15). A chiller unit74may be connected to these manifold connectors to circulate a fluid coolant and desirably a liquid coolant such as a water and antifreeze mixture through the tank coil(s). The tank may also have a solvent inlet76connected by suitable piping to a manifold solvent inlet connector78for supplying solvent to the tank and an outlet80for delivering solvent from the tank. This tank may also have a nitrogen inlet port82connected by suitable plumbing to a manifold nitrogen inlet connector84accessible from outside of the back of the enclosure and a solvent return inlet86. The solvent tank may be made of steel and constructed to withstand sufficient super-atmospheric pressure to maintain the vaporizable solvent in liquid form at exterior atmospheric temperatures within and surrounding the enclosure with a suitable safety margin.

As shown inFIGS.5and6, the plant material container26may be surrounded by a cooler or chiller coil88and an insulating sleeve89which preferably may be two spaced apart walls enclosing a vacuum. The material container may have a top access opening90which may be closed and sealed by a readily removable cover92which in its closed position may be firmly releasably secured to the container by a series of circumferentially spaced apart threaded fasteners94carried by a flange96fixed to the container. The cover92may be connected to the container by a suitable hinge98to facilitate manual opening and closing thereof. When the cover is open a material carrier cartridge100may be generally axially inserted into or removed from the container. The cartridge may have an open top102with a strap handle103and adjacent to the other end a removable filter assembly104which may retain plant material in the cartridge, admit solvent into the cartridge, and permit a solvent and extracted plant oil mixture to flow out of the cartridge and into the container26and through an outlet106adjacent the bottom of the container. The container also has a solvent inlet108desirably adjacent a lower portion of the container.

To facilitate insertion into and removal of the material cartridge100from the container it may be mounted in the enclosure22to be movable as shown inFIG.6from an upright position completely within the enclosure to a tilted outward position in which the upper portion of the container and its access opening90extends outwardly of the front of the enclosure and desirably underlies the open overhead door48. As shown inFIGS.6and7the container may be movably mounted in the enclosure by a sleeve110extending transversely of and attached by brackets to the container and rotatably received on a shaft112fixed by brackets to a support rail114of the enclosure. The container may be moved between its upright and tilted positions by an air cylinder116with a piston rod118pivotably connected to a bracket120fixed to the container and adjacent the other end the cylinder may be pivotably connected to a bracket122attached to a support124fixed to the rail114. As shown inFIGS.6and8the material container26may be releasably retained in its upright position inside the enclosure22by a latch mechanism126carried by an enclosure frame member128and actuated by a pneumatic cylinder130with a piston rod132pivotably connected to the latch mechanism and adjacent the other end the cylinder case may be pivotably attached to a bracket134carried by a frame member136of the enclosure. The container26may have a purge port138and a vacuum port140, desirably adjacent the top of the container.

As shown inFIG.5, the collection vessel28may be encircled by a heater coil142surrounded by an insulator sleeve144preferably in the form of two spaced apart walls enclosing a vacuum. This vessel may have a solvent and oil mixture inlet146, gaseous solvent outlet148and an access opening150with a removable cover152each desirably adjacent the top of the vessel, and adjacent its bottom a liquid oil outlet154. Through suitable conduits with solenoid flow control valves the heater coil142may be connected to manifold inlet and outlet connectors156&158accessible from the exterior of the enclosure. A liquid solvent in the collection vessel may be heated to a gaseous state by a heater unit160connected to the manifold inlet156and outlet158and circulating a heated fluid which is desirably a liquid through the heater coil142.

For recovery and reuse of the gaseous solvent from the collection vessel28it may desirably be passed through a sieve30to remove moisture from it (which typically came from the plant material) such as a molecular sieve with3A and/or4A sieve beads. A heater coil164may be in heat transfer relationship with the sieve30and connected to the manifold connectors156&158so that in use the solvent passing through the sieve is maintained in a gaseous state. The gaseous solvent from the sieve may be compressed such as by the compressor or pump32and supplied to the heat exchanger34to condense it to a liquid state and then the condensed liquid solvent may be returned to the solvent tank24. The heat exchanger34may be of a 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 coolant circulated through the heat exchanger such as by the cooling unit74. If all of the gaseous solvent is not condensed to a liquid state by the heat exchanger, any remaining gaseous portion may also be transferred to the solvent tank in which the pressure will rise and condense to a liquid state the remaining gaseous solvent.

During operation of the extractor apparatus20, to create a sub-atmospheric pressure inside the enclosure22and if any solvent leaks were to occur in the system to avoid any build-up of flammable solvent gasses within the enclosure, the exhaust system36continuously moves air through and across the inside of the enclosure as indicated by the arrows170inFIG.9. This exhaust system may have within the enclosure and desirably along one side wall an inlet air duct172communicating with an air inlet opening174to the exterior of the enclosure and having a plurality of air vents or slots176through which air may flow into the enclosure and on the other side wall an outlet air duct178communicating with an explosion proof exhaust fan180preferably disposed outside of the enclosure. The outlet air duct178may have a series of vents such as slots182through which air may flow into the duct when the exhaust fan is operating. The exhaust fan may communicate with the outlet duct through a suitable hose or pipe184as shown inFIG.2.

As shown inFIGS.10-12when the overhead door48is open, such as for an operator opening the cover92of the material container26for removal or insertion of a material cartridge100, the underside of the overhead door also carries a duct186communicating with the exhaust fan and having a series of vents or slots188to ensure that any residual solvent gases are also evacuated through the exhaust fan180and thus do not enter into the atmosphere surrounding the exterior of the enclosure. This duct may be connected by a flexible hose190to the outlet duct178and thus the exhaust fan. Desirably when the overhead door48is open the flow rate of the exhaust fan may be increased to ensure that any gaseous solvent does not escape to the atmosphere surrounding the exterior of the enclosure. The outlet192of the exhaust fan may be piped to the exterior of a building in which the extractor apparatus20is used to avoid the buildup of any gaseous flammable solvent within the building or room in which the extractor apparatus is operated or used.

As shown inFIGS.13and14, the enclosure22may have the fire suppression system38which automatically detects a fire and discharges a fire extinguishing agent within the enclosure. This system may have within the enclosure spray heads194connected by suitable conventional plumbing196to a pressurized container198with a fire extinguishing agent therein which as shown inFIG.2is desirably mounted outside of the enclosure to facilitate monitoring and as needed recharging and/or replacing of the container with another freshly charged and pressurized container. This fire extinguishing system may also have sensing tubes200inside of the enclosure which communicate with a normally closed discharge valve202connected to the container. The sensing tubes are configured so that when they detect sufficient heat (typically produced by a fire) they rupture resulting in a drop in the super-atmospheric pressure within the tubes which activates the valve202to discharge a fire extinguishing agent through the spray heads194within the enclosure. The fire extinguishing agent may be a Class B agent typically of dry chemical powders, or a film forming foam. This fire extinguishing agent desirably may be dry or multi-purpose dry chemicals such as ammonium phosphate or halogen agents such as Halon1301or1211. Many alternative fire extinguish systems are known to skilled persons and may be used including without limitation a highly pressurized carbon dioxide system.

The chiller unit74may through appropriate plumbing and control valves circulate a fluid coolant and desirably a liquid coolant such as a water and antifreeze mixture with rust inhibitors through the cooling coil(s) of the solvent tank24, material container26, and heat exchanger34. The chiller unit may circulate a coolant liquid which usually may be in the range of about −90° to −40° C. The chiller unit may be a commercially available refrigeration unit or other chillers known to persons of ordinary skill in the art and desirably may be disposed outside of the enclosure22and connected through suitable conduits to coolant inlet and outlet connectors70&72carried by the manifold and accessible from outside of the enclosure. Typically, solenoid actuated valves may control the flow or flow rate and cycling of the coolant to the solvent tank, material container, and heat exchanger and may be actuated, cycled and controlled by the electronic controller or PLC42.

The heater unit160may supply a heated fluid which is desirably a heated liquid such as a hot water and antifreeze mixture or other suitable liquid to the coil142of the collection vessel28and coil164of the sieve34through the connectors156&158and their associated plumbing and solenoid control valves. Suitable forced circulation liquid heater units are commercially available and known to persons of ordinary skill in the art. The heated fluid supplied to the heating coils of the collection vessel and the sieve usually may be at a temperature in the range of 100 to 160° F. Alternatively, the collection vessel and the sieve may be heated by electric heaters in thermal heat transfer relationship with or within respectively the collection vessel and the sieve.

As shown schematically inFIG.17, for automated control of the process carried out by the extraction apparatus various components may be plumbed and connected together through suitable solenoid control valves which may be actuated, cycled and controlled by the electronic controller or PLC42. The solvent tank24may be connected through manifold connector84to a source of compressed nitrogen gas through suitable plumbing with a solenoid actuated flow control valve204with open and closed states which desirably is in series with a downstream manual shut-off valve206. Compressed nitrogen gas may be supplied to the solvent tank if and as needed to force liquid solvent from the tank into the material container. The inlet76of the solvent tank may be connected through suitable plumbing with a solenoid control valve208with open and closed states to the manifold fill port78and desirably with a downstream manual shut off valve210. The outlet80of the solvent tank may be connected to the inlet212of the material container26through suitable plumbing including a solenoid actuated control valve214movable to open and closed states and desirably an upstream manual shut off valve215. To facilitate automatic cycling and control of the valve204,208, and214by the PLC, a temperature sensor216, pressure sensor217, and solvent liquid level sensor218may be operably associated with the solvent tank24to provide inputs to the PLC. The solvent tank may also have a weight sensor220of the weight or quantity of liquid solvent in the tank.

The material container26may be connected to a manifold purge connector224by suitable plumbing through a solenoid actuated control valve226with open and closed states. The material container may also be connected to a manifold vacuum port228through suitable plumbing with a solenoid actuated control valve230with open and closed states. The outlet232of the material container may be connected to an inlet146of the collection vessel28through suitable plumbing including a solenoid actuated flow control valve234with open and closed states. These valves may be cycled and controlled by the PLC42. To facilitate automatic control by the PLC, a temperature sensor236, pressure sensor238, and a solvent liquid level sensor240may be operably associated with the material container to provide inputs to the PLC.

The collection vessel28may also be connected to the manifold vacuum connector228through suitable plumbing including a solenoid actuated control valve242movable to open and closed states and cycled and controlled by the PLC. To facilitate automatic operation, a temperature sensor244, pressure sensor246, and liquid level sensor248may be associated with the collection vessel to provide inputs to the PLC. The outlet154for plant oil of the collection vessel may be connected to either a manual valve250movable to open and closed states by the operator or desirably connected to an outlet connector (not shown) accessible from the exterior of the enclosure through suitable plumbing including a solenoid actuated flow control valve252movable to open and closed states and controlled through the PLC and the operator by the HMI interface.

The gaseous solvent may flow from the collection vessel outlet148to an inlet256of the sieve30through suitable plumbing including a solenoid actuated flow control valve258movable to open and closed states. The sieve may have an associated inlet pressure sensor260and an outlet pressure sensor262which may provide inputs to the PLC. A sieve outlet264for gaseous solvent may be connected to the inlet266of the compressor or pump32through appropriate plumbing including a solenoid actuated control valve268movable to open and closed states. The outlet270of the compressor or pump may supply compressed gaseous solvent at a higher pressure to a gaseous fluid inlet272of the heat exchanger34through suitable plumbing including a flow control valve274movable to open and closed states and if desired this valve may also be configured to provide a variety of different flow rates between its fully open and fully closed states. An outlet276from the heat exchanger of at least predominantly if not only condensed liquid solvent may be returned to the solvent tank24through suitable plumbing including a solenoid actuated flow control valve278movable to open and closed states and downstream of this valve desirably a manual flow control valve282. Each of these solenoid valves may be cycled and controlled by the PLC.

As previously stated, the heat exchanger cooling coil is also connected to the manifold inlet and outlet connectors70&72through suitable plumbing conduits and if desired the inlet may include a solenoid actuated flow control valve movable to open and closed states and if desired to various flow rate states to further facilitate automatic operation by the PLC.

As shown schematically inFIG.18, each of the temperature, pressure, and level sensors and the weight sensor is electrically connected to an input of the PLC and each of the solenoid actuated valves is connected to an output of the PLC typically through a driver to change the state of the valve for automatic control of the particular extraction process being carried out by the PLC.

The HMI44is electrically connected to the PLC42to enable the operator of the extractor apparatus20to enter various times, temperatures, and other variables for running a particular extraction process. Typically, this HMI will also display in a form viewable by the operator the implementation and status of various steps of the specific process being automatically carried out by the extractor apparatus through suitable software and any firmware executed by the PLC to control the various solenoid valves in response to the data inputted by the operator and any needed or desirable inputs from the appropriate temperature, pressure, level and weight sensors. To prepare for an operating cycle of the extractor apparatus20an operator may load plant material into the cartridge100and insert the cartridge of plant material into the open end90of the tilted-out material container26and then manually close and seal the cover92of the material container with the cartridge fully within the container. The operator may then move the material container to its upright position fully within the enclosure and close the overhead door48and the container door52. If desired proximity sensors or switches may be associated with the overhead door and the container door to indicate whether they are closed and prohibit the beginning of an automated process unless and until they are closed. After the operator has entered the desired time, temperature, etc. data for a specific desired process to be run, the process may be started by pressing or touching a start icon on the operator HMI for the extractor apparatus to take over and automatically run the extraction process. Depending on the data inputted by the operator the PLC may apply a vacuum to the material container and collection vessel (and if desired through the collection vessel to the sieve, at least the inlet side of the compressor and depending on its construction to the heat exchanger) to remove substantially all oxygen from the system to thereby avoid any potentially combustible oxygen and solvent mixture being present in the apparatus system. Typically, the PLC would control and verify the pressure and temperature of the solvent in the solvent tank to ensure it is at a desired temperature to supply liquid state solvent to the material container. If needed the PLC will control the chiller unit to achieve this temperature. If desired, the PLC also may be programmed to use the input of the weight sensor220to determine if the solvent tank24has enough liquid solvent in it to run the complete process. When the solvent in the tank is at this desired temperature the PLC will open and control the valve214to transfer liquid solvent into the material container26to a desired level of liquid solvent therein which may be sensed by its associated level sensor240and when this level is reached the PLC will initiate closure of this solvent flow control valve. Thereafter, the plant material in the material container will be contacted with or soaked in the liquid solvent for a period of time (T1) inputted by the operator for the specific process to be run by the extractor apparatus. When this period of time is completed the PLC will open the control valve234to transfer the liquid solvent and extracted plant oil mixture to the collection vessel28and then upon completion of this transfer close this valve. If desired, for a particular process another quantity of liquid solvent from the solvent tank may be transferred into the material container to further contact and/or soak the plant material therein for a second period of time (T2) to obtain a further plant oil and solvent mixture and when this second time period (T2) expires the PLC will open the solenoid valve234to transfer this further solvent and plant oil mixture to the collection vessel28and then close this valve. Usually this second period of time (T2) is substantially less than the first period of time (T1).

Next, the PLC typically initiates heating of the collection vessel28and the sieve30, turns on the compressor pump32and initiates flow of coolant through the heat exchanger34. The PLC also opens the valves258,268,274, and278to permit the flow of gaseous solvent from the collection vessel into and through the sieve, to the compressor pump32, and compressed solvent gas through the heat exchanger34where at least most if not all of the solvent gas is condensed to a liquid state and returned to the solvent tank24. In the collection vessel the liquid solvent is heated sufficiently to be converted to a gaseous state and thereby be separated from the plant oil which accumulates in the bottom of the collection vessel. The period of time (T3) of heating of the collection vessel28and sieve30, operation of the compressor38and circulation of coolant through the heat exchanger34may be either initially programmed by an operator entering this time through the HMI to the PLC or with suitable software the PLC can monitor the temperature, pressure, and liquid level in the collection vessel to determine a suitable period of time T3to ensure that essentially all of the liquid solvent in the collection vessel is converted to a gas state and transferred from the collection vessel. After the T3period of time is completed, the PLC may discontinue heating of the collection vessel28and the sieve30, turn off the compressor32, discontinue circulation of coolant through the heat exchanger34, and close the valves258,268,274, and278. Thereafter, the plant oil may be removed from the collection vessel28typically for further processing. The plant oil may be removed through a drain valve plumbed to the bottom of the collection vessel and movable to open and closed states. This drain valve may be either a manual drain valve250which is manually opened and closed by an operator and opened when it is desired to remove plant oil from the collection vessel or a solenoid actuated drain valve252controlled by the PLC and opened and closed by an operator through the HMI. If desired, after the time period T3is completed and prior to removing the plant oil from the collection vessel, the valve242may be opened to provide a vacuum to the collection vessel for a short period of time to remove any gaseous solvent remaining in the collection vessel and then closed and desirably the pressure within the collection vessel returned to atmospheric pressure or if desired to a relatively low super-atmospheric pressure to increase the flow rate of plant oil out of the collection vessel when the drain valve is open.

With suitable software, the PLC throughout the process may monitor the temperature, solvent level, and pressure inside the solvent tank24, material container26, and collection vessel28and the inlet and outlet pressures of the sieve30, and make any needed adjustments to the various temperatures, pressures, and/or liquid levels to expedite and improve the efficiency of the process. The PLC may also monitor the enclosure22of the extraction apparatus through an appropriate sensor for any hydrocarbon solvent leaks or other harmful effects, and if detected close all of the solenoid valves, shutdown the process and maximize the cubic foot per minute flow rate of the exhaust fan to avoid the creation of a potential fire or explosive condition in the enclosure. If desired, process data may be logged by the PLC for each batch of plant material processed by the extraction apparatus20so that an operator may see the exact conditions in each of the solvent tank, material container and collection vessel that occurred throughout the extraction process.

If desired a single operator may run a plurality of these extractor apparatuses22such as 4-6 apparatuses since each apparatus automatically carries out an extraction process and only requires an operator to load plant material into the material container and after extraction of plant oil to remove the material container, and to enter a limited amount of data for an apparatus to automatically run a specific process and if desired manually remove plant oil from the collection vessel.

While the form of the extraction apparatus disclosed herein constitutes presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or 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.