Patent Grant
10589322
The present invention relates to the cleaning a source material of soluble compounds and sequestering those soluble compounds for recovery. For more specifically, extraction of valued soluble compounds from a source comprising plant matter.
Modern materials as well as an advanced understanding of mechanical engineering allow for compounds which normally exist at standard temperature and pressure as a gas to be manipulated by a modified atmosphere into existing in a sub critical or super critical state. In this state, normally gaseous compounds like Carbon Dioxide or elements like Xenon exhibit powerful solvation and other traits favorable for cleaning or extraction, for example low surface tension. In the case of Carbon Dioxide a high degree of nonpolar solvation combined with a low surface tension and low toxicity makes it an excellent washing fluid for cleaning or extracting. These properties act in concert to effectively extract a soluble compound from a starting material, or dislodge non-soluble particles from a starting material with the help of agitation. As a result, the use of such washing fluids has already become a mainstay in various fields to accomplish washing of soluble and insoluble substances from a starting material.
A FIRST EXAMPLE, U.S. Pat. No. 5,267,455 A, published on Dec. 7, 1993 to Dewees et. Al. teaches A dry cleaning system particularly suited for employing supercritical CO2 as the cleaning fluid consisting of a sealable cleaning vessel containing a rotatable drum adapted for holding soiled substrate, a cleaning fluid storage vessel, and a gas vaporizer vessel for recycling used cleaning fluid is provided. The drum is magnetically coupled to a motor so that it an be rotated during the cleaning process. The system is adapted for automation which permits increased energy efficiency as the heating and cooling effect associated with CO2 gas condensation and expansion can be channeled to heat and cool various parts of the system.
A SECOND EXAMPLE U.S. Pat. No. 5,669,251 A, Published on Sep. 23, 1997, to Carl W. Townsend and Edna M. Purer teaches, A liquid carbon dioxide dry cleaning system that employs a rotating basket inside a dry cleaning vessel that is powered by hydraulic flow. The present invention is particularly useful as a dry cleaning system that uses liquid carbon dioxide as the cleaning agent. The dry cleaning system has a pressurized vessel containing a liquid carbon dioxide bath. The basket is disposed in the vessel and has a plurality of openings around its periphery. A plurality of roller bearings are disposed between the basket and the vessel that allow it to rotate within the vessel. A plurality of manifolds are disposed between the vessel and the basket that have nozzles that produce jets of liquid carbon dioxide that agitate the garments. The nozzles are aligned with the plurality of openings in the basket. A pump is coupled between the manifolds and the vessel for circulating the liquid carbon dioxide to produce the jets that clean the garments and rotate the basket. Additional sets of manifolds and nozzles and a valve may be provided to cause the basket to selectively counter-rotate.
A THIRD EXAMPLE U.S. Pat. No. 5,467,492 A, Published on Nov. 21, 1995, to Sidney C. Chao teaches Liquid carbon dioxide, in combination with agitation and, optionally, with process enhancers, such as surfactants, and solvents, such as water, is used to remove contaminants from garments or fabrics. Both apparatus and process are disclosed. Carbon dioxide-cleaned garments are rendered free of odor, require no drying, and the cost per unit solvent (by weight) is a fraction of that of conventional solvents.
A FOURTH EXAMPLE U.S. Pat. No. 5,766,368 A, Published on Jun. 16, 1998, to Charles W. Bowers teaches, A method of cleaning an integrated circuit chip module prior to attaching wire bonds thereto. The method involves disposing a module containing an integrated circuit chip and IC bond pads without wire bonds in an environmental process enclosure. A carbon dioxide jet spray cleaning system having a spray nozzle and orifice assembly is disposed the environmental process enclosure. A jet spray of carbon dioxide is generated using the jet spray cleaning system. The carbon dioxide jet spray is directed onto the surface of the module such that the spray impacts the IC bond pads and module bond pads to clean unwanted adhesive from the surface of the module and thus clean the IC and module bond pads.
A FIFTH EXAMPLE U.S. Pat. No. 6,066,032 A, Published on May 23, 2000, to Michael R. Borden, Thomas J. Kosic and Charles W. Bowers teaches Apparatus and methods for removing particles from a surface of a semiconductor wafer or optical component using a carbon dioxide snow spray directed at the wafer or component while simultaneously irradiating the surface with a laser beam. The apparatus comprises a carbon dioxide jet spray cleaning system disposed within an environmental cleaning station of a processing system that processes the wafer or component. The processing system is a conveyorized system wherein a conveyor belt or web transports wafers or components from processing station to processing station. The cleaning station includes a recirculating blower system, a laminar flow screen, a high efficiency particulate air filter, and a ducting system for recirculating purified air or inert gas. The cleaning station contains a jet spray nozzle that produces a carbon dioxide snow spray. The jet spray nozzle is coupled by way of a manifold to a liquid carbon dioxide tank that supplies liquid carbon dioxide to the jet spray nozzle. The wafer or component is grounded to prevent static charge buildup. A carbon dioxide laser, operating at 10.6 microns, produces a laser beam that is generally aligned with the carbon dioxide snow spray so that the beam and spray overlap. The laser beam heats the surface of the wafer or component to compensate for the cooling effects of the carbon dioxide snow.
A SIXTH EXAMPLE U.S. Pat. No. 6,071,408 A, Published on Jun. 6, 2000, to Robert William Allington et al. teaches to provide performance particularly in handling supercritical extraction systems, a specially designed pump includes a cam-driven, single-plunger with a cam having a profile that enables the pumping system to avoid destructive reverse torque on the cam, gear train and drive motor after the cam passes top dead center. The fluid volume leaving the pump is determined by measuring only pressure or other parameters related to flow and movement of the plunger. Measurement of the fluid volume leaving the pump is useful for recording or indicating the flow rate while the pump is operating.
A SEVENTH EXAMPLE U.S. Pat. No. 9,132,363 B2, Published Sep. 15, 2015 by, Andrew Paul Joseph teaches an extraction apparatus comprises an extraction vessel configured to remove an extracted material from a source material in contact with a process fluid to form a mixture. The apparatus further comprises a separation chamber and a process fluid circulation conduit, the conduit comprising a separation portion configured to receive the mixture and permit a portion of the extracted material to separate from the mixture within the separation chamber. The apparatus further comprises a temperature regulator configured to permit re-circulation of a temperature regulation fluid and regulate the temperature of the process fluid.
Particularly in examples U.S. Pat. Nos. 9,132,363 B2 and 6,071,408 A it is seen that the solvation power and low toxicity of substances like carbon dioxide are an advantage over more traditional nonpolar solvents.
These previously invented apparatuses have not always seen widespread use and are inaccessible to many because of their high equipment acquisition costs as well as high operation and maintenance costs. This is due to complex designs, with many moving parts which fail to effectively leverage the properties of the washing fluids they employ. As a result, the current paradigm of sub critical and super critical washing and extraction devices comprises expensive and large machines. These machines often have low flow rates of cleaning fluid over the starting material. The cause of these low flow rates is chiefly the machines reliance on high pressure pumps and heat exchangers to provide liquid or supercritical fluid for the extraction. These pumps are expensive and have many moving parts which become worn, they also use a lot of electricity, they are also noisy and these machines leave a large footprint. Additionally, by the very nature of their design in compressing the gaseous washing fluid the heat generated during this process needs to be removed and the temperature lowered even further to get the gas into the desired state, this comes at a great energy expenditure. But perhaps the most critical flaw in this methodology of circulating the washing fluid lies in the rate of flow they can provide to the extraction chamber. These low flow rates are a function of their basic design, compressing gas and cooling the pressurized gas to form a liquid. Even the largest compression pumps have a relatively limited ability to produce high volumes of liquefied gases, in the case of Carbon Dioxide the ratio of volume when comparing gas to liquid, which is also known as the expansion ratio is 450:1. What this means is that a pump must compress 450 liters of Carbon Dioxide gas to produce only one liter of liquid Carbon Dioxide. Given the high pressures that needed to be reached a high rate of compression is an arduous task for pumps being currently used and is the cause of the low flow rates seen in today's available machinery. Adding to this problem is the fact that these low flow rate necessitate the extraction chambers to be long and thin. This hampers efficiency due to a higher percentage of the source material being in contact with dirtier washing fluid for a longer period of time compared with a wider, shorter chamber. Additionally, there is an inherent scaling problem when using pumps to compress and liquefy washing fluid gas, more liquid flow would require a bigger pump, meaning increased upfront and maintenance costs; as well as electrical costs and floor space required. Additionally, the ways in which turbulent fluid acts on a packed bed is not ideal for a succinct and controlled extraction of a wide bed of material, turbulent fluids do not evenly flow through a packed bed of material.
One of the physical properties which is often neglected in the aforementioned apparatuses is the low latent heat of vaporization (LHV) that common washing or extracting fluids have. These common washing or extraction fluids are chemical elements or compounds which are found to be in a gaseous state when under standard atmospheric pressure and at room temperature. For example, carbon dioxide has a LHV of 574 kJ/kg while water has a LHV of 2257 kJ/kg. For this reason, evaporating a comparable mass of each of these substances will necessitate vastly different amounts of energy input. Carbon Dioxide is favorable to water in terms of amounts of energy required to vaporize or condense the compound. Additionally, the low LHV of carbon dioxide means that the energy transfer from vapor phase to liquid phase a condensing surface is equally low, resulting in low cooling costs which yield a rapid condensation rate. For these reasons, it is highly advantageous to distill and condense substances such as Carbon Dioxide within an extraction or washing system as a method for obtaining pure Carbon Dioxide from the contaminated stream coming off of the starting material as opposed to using compression and heat exchange to achieve the same effect. In the present disclosure, the starting material is envisioned to be a plant or any similar natural occurring product comprising plant matter. By way of example only, the presently described Carbon Dioxide extraction method allows for extraction of pure Tetrahydrocannabinol (THC) from the cannabis plant. Beyond the obvious advantages of using evaporation and condensation as opposed to the more traditional compression/decompression and the resultant turbulent flow over the starting material the present invention has other advantages as well. Leveraging laminar flow inside of the extraction chamber when used in conjunction with evaporation and distillation not only solves the scaling problem entirely but a wider, larger chamber can be used with a higher flow rate to achieve a more uniform and rapid extraction. Fluid flow inside the chamber of the present invention is laminar when introduced to the packed bed of starting material, thereafter the non-turbulent nature of fluid flow would persist and provide can even extraction across even a very wide extraction chamber. This is accomplished by having a closed loop within the extraction chamber, with a boiling chamber of contaminated washing fluid evaporating, having the evaporated gas pass through a fan which maintains a positive pressure differential downstream. Downstream there is a condensation apparatus which causes with condensate to pool beneath it, above a resistance filter. Beneath the resistance filter is the extraction chamber, which during normal operation of the device is perpetually saturated with washing fluid, this washing fluid flows freely back into the boiling chamber by means of an open pipe. As a result of the pressure difference within the system, pure washing fluid is forced through the extraction chamber in a uniform way, returning to the boiling chamber where the washing fluid again evaporates to continue the cycle. Thus achieving a low cost, highly efficient method of extraction or cleaning.
Referring to
After washing fluid has entered chamber 27 and risen above the opening of insulated pipe 52 the remainder of fluid which flows into chamber 27 will drain into insulated pipe 52 and subsequently pipe 48 where the washing fluid will then enter extraction chamber 42 from the bottom. At this time condensation unit 35 along with fluid jacket 34 and 43 are activated by the operator in the same fashion as condensation unit 22 and fluid jacket 20 were previously activated; filling with cold fluid and thereby causing washing fluid to condense and drip onto resistance filter 38. The operator at this time also begins a flow of fluid within fluid jacket 28, the temperature of this fluid is warmer than the fluid flowing within fluid jackets 33, 43 and within the condensation coils 35. Once fluid level sensor 36 verifies the washing fluid has filled up the entirety of chamber 42 as well as partially filling chamber 33, impeller fan 32 is activated by the operator. Impeller fan 32 draws gas through insulated pipe 31 from chamber 27 and forces it into chamber 33. This begins the extraction or washing process. Liquid washing fluid is then pushed through laminar flow filter 38 via the increase in relative atmospheric pressure above the liquid in chamber 33 as compared to the lower relative atmospheric pressure within chamber 27. The liquid washing fluid passes through laminar flow filter 38 the liquid washing fluid then into extraction chamber 42 and subsequently into pipe 48 then 52 and finally boiling chamber 27. It must be noted that as the washing fluid is forced through filter 38 it emerges in a state of laminar flow as the washing fluid flows into chamber 42. To maintain a rate of flow that keeps the liquid emerging from the laminar flow filter in laminar flow fan 32 along with fluid jacket 28, 34 and condensation units 33 may be controlled by microprocessor using information from sensors, 29, 30, 36, 37, and 44 to manipulate the rate of condensate formation within chamber 33 and the rate at which the condensate is forced through filter 38. The washing fluid then cleans or extracts soluble and/or insoluble materials from the source material before exiting via the orifice formed in the bottom of extraction chamber 42 by pipe 48; whereupon the washing fluid continues flowing through jacketed pipe 52 then into chamber 27.
Once the washing cycle has concluded the operator stops the flow of coolant into fluid jackets 34 and 43 as well as condensing unit 35, additionally the fans on condensing units 35 are similarly disengaged by the operator. With hatch 14 and valve 53 closed, valve 26 may be opened by the operator to permit pressure equalization of the entire system via pipe 25. With fan 32 running to provide positive pressure in chamber 36 in order to force all washing fluid into chamber 27; valve 18 is opened by the operator to drain the washing fluid into chamber 12 via pipe 17. Once the full amount of fluid is deposited in chamber 12 as confirmed by fluid level detector 15, and 29. Valve 18 as well as valves 26 and 56 are closed. This permits the opening of valve 54 in order to equalize the pressure within the interior of chambers 27, 33 and 42 with normal atmospheric pressure. Once this depressurization is complete it is then possible to decouple chamber 42 from chamber 33 as well as pipe 52. This is achieved by the operator removing locking devices 40 and 50 from flanges 39 and 41 as well as flanges 49 and 51, respectively. This permits access and removal of the depleted or cleaned source material held within basket 45 which can then be retrieved. Subsequently the operator may place fresh source material into basket 45 which is then placed back into chamber 42 in preparation for the next cycle. The operator may then refit chamber 42 into place. Simultaneously the operator may activate fluid jacket 13 which in turn is provided with warm fluid. Additionally, the operator activates fluid jacket 21 and condensation unit 22. Condensation units 22 fans are activated and fluid jacket 21 and condensation unit 22 are provided with cool fluid as compared to the fluid within fluid jacket 13 to compel the washing fluid within chamber 12 to evaporate and condense on condensation units 22 within chamber 20.
Once all the washing fluid has been evaporated from chamber 12 and deposited within chamber 20, the clean fluid may be reintroduced to chamber 27 during the next washing or cleaning cycle. In this case once the fluid has been emptied from chamber 20 into chamber 27 via corresponding valve and pipe 56 and 55 after pressure has been equalized within both systems via valve and corresponding pipe 26 and 25. Any remaining pressure within chambers 12 and 20 is vented from valve 53. At this point the extraction or washing cycle is considered completed and using access hatch 14 any resulting residue may be retrieved. Additionally, valve 57 may be closed by the operator to upon completion of the extraction cycle to sequester the entirety of the washing fluid within chamber 20 in the event the device is to be placed out of commission for an extended period of time.
In yet another embodiment of the invention the laminar flow filter comprises a resistance heater which combined with the positive pressure from the inline fans and additional heat from the fluid jacket surrounding the extraction chamber causes a temporary phase transformation of the subcritical liquid solvent to a supercritical phase of the solvent. The solvent then passes through the interior of the extraction chamber as well as the filters at the bottom in this super critical phase. The solvent then passes through a cooling column while moving towards the boiling chamber, through a pressure regulation device potentially equipped with an antifouling mechanism and into the boiling chamber. It must be noted that the entire system would need to be operated at a higher temperature and pressure to make this possible.
In yet another embodiment of the invention there may be a vacuum device attached to the pressure relief valve in order to facilitate the recovery of a higher percentage of gaseous washing fluid gas in the event that the solvent gas is valuable. One such gas is xenon. Or in the even the starting material or targeted soluble compounds are subject to degradation by environmental conditions.
In yet another embodiment the extract recovery chamber may be washed automatically with a nonpolar solvent such as anhydrous ethanol or isopropyl alcohol. In this embodiment, it would be necessary to have a closed loop dehumidification device fitted to chambers 20, 12 as well as insulated pipe 19 to remove any traces of solvent from the chamber to decrease the likelihood of system wide contamination.
Also in yet another embodiment the extraction chamber may employ mixing via baffles within the basket, via a rotating basket with or without baffles employing agitation to churn the material within the basket.
Thus there has been described a new and improved method for washing or extracting, which manipulates a liquid or supercritical solvent to flow over the starting. The embodiments described above are merely illustrative of some of the many specific embodiments that represent applications of the principles of the present invention. Numerous and other arrangements can be readily devised by those skilled in the art without departing from the scope of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5267455 | Dewees | Dec 1993 | A |
| 5377705 | Smith, Jr. | Jan 1995 | A |
| 5467492 | Chao | Nov 1995 | A |
| 5669251 | Townsend et al. | Sep 1997 | A |
| 5766368 | Bowers | Jun 1998 | A |
| 6066032 | Borden et al. | May 2000 | A |
| 6071408 | Allington et al. | Jun 2000 | A |
| 6536059 | McClain | Mar 2003 | B2 |
| 9132363 | Joseph | Sep 2015 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20190168267 A1 | Jun 2019 | US |
