Patent Publication Number: US-10315199-B2

Title: Method for collection of integer glandular trichomes

Description:
FIELD OF THE INVENTION 
     This disclosure relates generally to the production of pure integer glandular trichomes from all plants bearing glandular trichomes, and more specifically to the production of &gt;96% pure integer glandular trichomes as resin from Cannabis plants. 
     BACKGROUND 
     Most plants have specialized hair-like trichomes structures on leaf surfaces, non-glandular trichomes being very common, glandular trichomes being less common. Glandular trichomes are a mixture of waxes, resins and oils capable of storing relatively large amounts of secondary metabolites, like terpenoids, as part of the “essential oil” of the plant, making them a target for the production of valuable small molecules. 
     For example, peppermint oil, consisting primarily of monoterpenes from glandular trichomes and minor quantities of sesquiterpens are synthesized and accumulated in specialized non-glandular trichomes pistils, hairs of the peppermint plant and essentially natural oils are extracted with heat and solvent are in common use as a flavor in numerous consumer products (e.g., chewing gum, mouthwash . . . ), in the confectionary and pharmaceutical industries as well. 
     Whereas since the distant past, 8000 B.C. up the present, Cannabis in various forms was either eaten or smoked, the major usage being a recreational drug all over the world, cannabinoids and their derivatives were the mainstay of early medicine and the seeds were integrated into most every cuisine around the world, Cannabis products have been consumed in various forms for thousands of years. Descriptions of medical uses in Chinese texts date from the first century A.D., disclosing oral consumption in herbal tea concoctions, used for pain relieving and sleep inducing. The use of cannabis in Hindu India was largely popularized by Shiva smoking the leaf or resin extracts for their psychoactive properties. The use was spread through Arab lands in the Middle Ages, before coming into Europe and the Americas. For centuries, Cannabis resin was made by hand rubbing the flowers or sifting with fine cloths as screens. 
     Cannabinoids are receiving just recently a new and increasing interest again for recreational freedom, State taxes, nutrition and pharmaceutical, commercial and industrial purposes. 
     In comparison to other parts of the plant, the integer glandular trichomes of the Cannabis Indica plants store the highest concentrated amounts of cannabinoids, in particular tetrahydrocannabinol (THC) and cannabidol (CBD). Almost all current research focuses either on genetically engineered plants exhibiting enhanced contents of THC, CBD or other molecules, or on medical applications of particular cannabinoids. The known extraction methods are usually dedicated to isolate a specific molecule and thus involve a solvent. For example, US 2013/0079531(to Barringer) teaches an ethanol extraction at −20° C. 
     There is to our knowledge very few methods to produce pure integer glandular trichomes. 
     U.S. Pat. No. 6,158,591 (to Delp) uses cold water and ice in a wash process to cause the resins to become brittle, while the remaining plant material becomes more flexible. Separation is accomplished using an ICE COLD® extractor apparatus having a washing chamber disposed above a settling chamber and a collection bottle placed below the settling chamber. 
     A re-interpretation of this process patent is a licensed device comprising of four or eight sieving bags of different mesh size for separating resin particles from various plant materials may be found for example under the name of “Bubble-Bags®”. 
     One drawback of the ice-water methods is that some valuable aromatic and sticky components of the resin material, the terpenes and light oils, are lost by dissolution in the water. Another drawback of these methods is that the resin is saturated for minimum one hour in water and must be quickly, carefully and thoroughly dried thereafter to avoid deterioration by fungal growth under moisture. These drawbacks may lead to an alteration or degradation of the organoleptic properties of the targeted integer glandular trichomes resin. 
     A dry process is known from the publication of Yerger et al, Plant Physiology, 1992, 99, 1-7, wherein, deep frozen plant material is placed together with crushed dry ice (CO2) in a vortex mixer. Glandular trichomes are then separated by sieving. This paper teaches that the dry ice particles act mechanically to separate trichomes from pistils. A corresponding device may be commercially available under the name of “Tumble Now®”. Such device comprises a sifting drum accommodating the plant material, tumbling inside a casing, so that the finer fraction of particles fall through the screen around the drum onto the bottom of the casing for later collection. The process is extremely sensitive to the operating parameters such as the temperature, the humidity and the process duration. A very cold and dry atmosphere is required, and short processing time is necessary to recover the resin with a higher purity. Under these conditions, the yield is low. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to provide a method of extraction together with a method of collection resulting in a lesser degree of the above drawbacks. In particular, it is the aim of the present invention to provide a processing method which results both in a high yield per hour of extraction processing and a high purity of the integer glandular trichomes in the collection process. An extraction method, or process, is hereby understood as a series of steps through which the integer glandular trichomes are removed from a raw plant material and suspended in water. The extraction method according to the present invention is an extraction process using an aqueous solvent flow. A collection process is hereby understood as a process to isolate the glandular trichomes from the remaining components resulting from the extraction steps. The collection process according to the present invention involves successive sieving steps to isolate the integer glandular trichomes according to their size. 
     Any resinous plant comprising glandular trichomes may be involved in the extraction and collection process of the present invention, such as cannabis, rose, or lavender and the result will be pure integer resin glands. The plants may be involved in the extraction process as dried or desiccated material, or as fresh cut plants. The complete plant material may be involved in the process, or only parts of the plants such as the leaves, the flowers, or the stems. The plants may be made into small elements before being processed or kept entire. 
     In one aspect, the present invention is directed to a method or process for extracting the integer glandular trichomes from a resin gland bearing plant material with the flow of high pressure cold water. The apparatus is provided with a means for delivering pressurized cold water. 
     In another aspect, the present invention is directed to a method or process for collecting glandular trichomes suspended in a resin rich water flow. 
     In another aspect, the present invention is directed to an apparatus adapted for extraction and collection of the integer glandular trichomes suspended in a resin rich water flow. The apparatus is in particular provided with several sieving means for isolating the integer glandular trichomes according to their size. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example of the spray extraction apparatus according to the present invention. 
         FIG. 2  shows the details of the sieving and collection unit according to a first embodiment. 
         FIG. 3  shows the detail of the sieving and collection unit according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to an apparatus comprising an extraction unit E, and a collection unit C. The extraction unit E comprises a spray-array  2  and a spray-table  3 . The spray-array  2  is suspended above the spray-table  3 . It comprises several nozzles  21  fed with pressurized cold water. The nozzles  21  are preferably disposed on a nozzle frame  21   a . The nozzle frame  21   a  may be fixed to a manifold  28  or directly attached with rigid ducts  22 . Alternatively, the nozzle frame  21   a  may be connected to a manifold  28  only through the ducts  22 . A duct  22  branched to each nozzle  21  supplies the refrigerated and pressurized water to the corresponding nozzle  21 . The ducts  22  are connected to a manifold  28 , which is fed by a flexible hose  29   a . A pump  23  and refrigerated pressurized expansion-tank  24  may be used to prepare the necessary amount of water before it is supplied to the manifold  28 . The usual domestic water distribution can be used to supply the pump  23 . 
     A water temperature comprised of between 0.5° C. and 2° C., and ideally around 1° C., is preferred for this extraction. Preferably, the same temperature is maintained through the collection process. 
     The pressure of the cold water at the spray level is advantageously comprised between around 1.5 and 3.5 bars, preferably between 2 and 3 bars, and ideally at 2.5 bars. 
     A trunk line  29   b  may be used to supply the pressurized cold water to the flexible hose  29   a  from the refrigerated pressurized holding tank  24 . The tank  24  may be used, in such a way that a predetermined amount of water is conditioned and stored before the process is triggered. The pressurized tank  24  may be refrigerated, by the means of usual refrigerating systems in such a way that the water stored within the pressurized tank  24  is maintained at 2.5 bar and a temperature close to 1° C. Multiple tanks  24  might be required for continuous work. 
     When working in a hot environment the delivery hose  29   a , the manifold  28  and the individual ducts  2 , may alternatively be embedded within a refrigerated area, not shown, so as to help maintain the water at the preferred temperature comprised between 0.5° C. and 2° C. during process. 
     The manifold  28  collects the pressurized water from the hose  29   a  and distributes it to the nozzles  21  through the ducts  22 . The manifold has thus one input I and several outputs O. The number of outputs O may be equal to the number of nozzles  21  in such a way that each output O is connected to a nozzle  21  through a linear duct  22 . A duct  22  designates a duct connected from one output O of the manifold  28  to one input at the nozzle  21 . Alternatively, the number of outputs O on the manifold  28  may be less than the number nozzles  21 . In this configuration, the pressurized water is fed to the nozzles  21  through branched ducts  22 , as shown in  FIG. 1 . The output O may also arrive to the nozzle  21  following a combination of linear and branched ducts  22 , providing the even flow of adequate pressure is not compromised. 
     The connection of the ducts  22  to the outputs O of the manifold  28  and to the nozzles  21  is performed by any usual fluidic connection means, such as tightening the extremity of the duct  22  onto a protruded shape of the manifold  28  and the nozzles  21 , or screwing or clipping together the two parts of a two-part connector. Alternatively, the ducts  22  may be integral to the manifold  28  and the nozzles  21 , in such a way that the spray-array  2  forms a single element of the apparatus  1 . The ducts  22  may be made of any rigid material such as metal or hard plastic material. They can alternatively be made of any usual flexible material, such as rubber, soft polymers, and any combination of flexible materials adapted to resist an internal pressure of up to 3.5 bars. 
     The spray-array  2  is placed in such a way that the nozzles  21  are oriented to direct the corresponding water jets downwards, in direction to the spray-table  3 . The number of nozzles  21  and the dimensions of the spray-array  2  may vary depending on the usage. A spray-array  2  of 0.2 square meters (40 cm by 50 cm) up to 0.4 square meters (50 cm by 80 cm) can comprise for example 20 to 40 nozzles  21 . The nozzles  21  are preferably dispatched on the spray-array  2  in a regular and homogenous manner, which is to say that the nozzle  21  are spaced from each other by an equal distance or a substantially equal distance. 
     As an example, a spray-array  2  can comprise 25 nozzles  21 , arranged on 5 rows of 5 wherein the distance between the nozzles  21  is constant and equal to around 10 cm. Other specific arrangements may be contemplated. The spray array  2  may for example comprise only 17 nozzles  21 , at any rate dispatched on a rectangular frame, which is preferably made of flat aluminum slats. 
     The nozzles  21  can be calibrated to provide a cone shaped water jet towards the spray-table  3 . Alternatively, a flared water shaped jet can be provided by the nozzles  21  in order to impact a specific operator targeted area on the spray-table  3 . The nozzles  21  may optionally be provided with a regulation means, not shown, to modify the shape of the water jet. A regulation means may for example comprise a screwed ring at the extremity of the corresponding nozzle  21 , which can be screwed or unscrewed to enlarge or reduce the nozzle aperture, and thus modify the shape of the water jet. Any other known water jet regulation means may be used. In any case, the pressure of the water supplied to the nozzles  21  is adapted to impact the spray-table  3  with sufficient strength to dislodge the resinous components, including the integer glandular trichomes of the plant material. Thanks to the water jet pressure, the glandular trichomes can be dislodged from the plant surface. The pressure of the water jet is determined so as to not damage the plant material being extracted on the spray-table  3 . 
     The spray-array  2  may be provided with an on/off valve  26 , which can be opened by the operator when pressurized water is required, and closed at the end of the process. The valve  26  may be manually actuated or actuated by the means of an electrical system. Alternatively or in addition, a pump command  27  may be included or connected to the apparatus  1 , so as to allow the user to activate and stop the pump  23 . 
     The spray-table  3 , placed below the spray-array  2 , comprises a rigid table frame  31 , and a meshed surface  32 . The table frame  31  may stand or be suspended by the means of spray-table links  33 . The spray-table links  33  may be rigid or flexible, and have all the same length in such a way that the spray-table  3  is horizontal or substantially horizontal. The meshed surface  32 , also designated as a porous screen, can be a synthetic surface stretched on the table frame  31 . In particular, it can be a polyester or a nylon filter screen material, such as screen printing mesh. The meshed surface  32  has a calibrated porosity comprised between 200μ and 300μ micrometers. The porosity is ideally around 250μ micrometers, which is larger than the size of the glandular trichomes to be purified. Upon impact of the jet forced water, the integer glandular trichomes are thus dislodged from the pistils holding them and pass sieved from the plant material through the meshed surface  32  while the larger vegetal impurities remain on the meshed surface  32 . 
     The spray-table  3  is placed horizontally at a distance from the spray-array  2  comprised between around 20 cm and 40 cm, preferably between 25 and 35 cm. A distance of around 30 cm is ideal. However, depending on the actual pressure and shape of the water jets, the distance may be adapted. The dimensions of the spray-table  3  may vary according to the amount of material to be purified. The spray-table  3  may for example firm a rectangular surface having its edge lengths comprised of between 150 and 250 cm. It can also be a surface having a width of around 240 cm and a depth of around 125 cm. Any other dimensions are also contemplated. 
     Below the spray-table  3  is placed a run-off device  4 . The run-off device  4  is preferably a non-porous surface adapted to collect the glandular trichomes which are washed through the spray-table  3  with the cold water flow. In a particular embodiment, the run-off device  4  may be provided with lips  41  on its edges to prevent spills of the flowing water. The run-off device  4  is advantageously provided with one or more gutter channels  42 , allowing the run-off water flowing along the lips  41  to arrive in the gutter channel  42 . The gutter channel  42  may be for instance placed at a corner of the run-off device  4 . Although the run-off device  4  is to be a flat surface placed quasi horizontally below the spray-table  3 , it is advantageously slightly inclined so as to facilitate the water flow through the gutter channel  42 . An inclination of up to &lt;10°, or comprised between 5° and 10°, with regard to the horizontal reference, is advantageously considered. Thus, the water flow does not remain in the run-off device  4 . In addition, the water flow, accelerated by the inclination of the run-off device  4 , allows all of the water to flow out of the run-off device  4 . The run-off device  4  may be suspended by several run-off device links  43 . The run-off device links  43  may be rigid or flexible. All the run-off device links  43  may have different length values in order to allow the run-off device  4  adopt the proper inclination. Alternatively, or in addition, one or more of the links  43  may be provided by an adjustment means  44  to adapt the length of the corresponding run-off device link  43  delivering the resin rich water flow into the sieving device  5  below. 
     Alternatively, the run-off device  4  may be a conical surface surrounded by a lip  41 , and provided with a gutter channel  42  at its lowest point. As above, the inclined surfaces of the run-off device  4  allow the water flow to spill out of the run-off device  4  through the gutter channel  42 . In this configuration, the gutter channel  42  is placed below the wash flow surface of the run-off device  4 . 
     The run-off device  4  may be made of any hard material such as glass, plastic, polymer material or metallic material. The wash flow surface of the run-off device  4  can alternatively be made of a flexible non-porous material stretched on a frame. 
     The dimensions of the run-off device  4  are slightly larger than the corresponding dimensions of the spray-table  3  above, in such a way that all the water flow passing through the spray-table  3  falls to the run-off device  4  for a gravity dispatch to the sieving device  5  from one out flow point of the gutter channel  42 . 
     The spray-array  2  comprises one or more fixation means  7 , so as to be suspended to an upper frame (not shown) or the ceiling. Fixation means  7  are preferably flexible, such as cables, iron wire, or any other equivalent flexible fixation means. Such a flexible fixation allows the operator to easily translate the spray-array  2  back and forth on a horizontal plan, so as to direct the water jets all over the surface of the spray-table  3 . A sweeping motion can thus easily be operated to wash off most all resin glands from the material placed on the spray-table  3 . If not flexible, the fixation means  7  may be articulated is such a way to allow the lateral/horizontal sweeping motion according to one or two horizontal axes. 
     Alternatively, the fixation means  7  may be provided with one or more guides which allow a horizontal motion, such as a beam or a rail, or a track. 
     Alternatively, or in addition, the fixation means  7  are elastic or comprise an elastic portion, so as to allow movement the spray-array  2  along a horizontal plane perpendicular to the spray table. To this end, the fixation means  7  may be provided with a spring  8  or any equivalent elastic element such as rubber. Any equivalent mechanical arrangement may also be used. The elastic properties of the fixation means  7  make it possible to optimize the distance of the nozzles  21  with regard to the spray-table  3 , so as to modulate the strength of the water jets on the plant material to be processed. It is clear that the hose  29   a  should have the sufficient flexibility to allow the motion of the spray-array  2 . 
     The dimensions of the spray-array  2  may be the same as the corresponding dimensions of the spray-table  3  if the spray array is to be fixed and provided with sufficient water jets to cover the full extraction surface of the spray table  3 . If spray-array  2  is alternatively of smaller dimensions with regard to the spray-table  3 , then the spray array  2  is mobile allowing the operator to move the water jets such as to impact in a sweeping motion the materials on the spray-table  3 . Its sweeping motion allows anyway to cover the full surface of the spray-table  3 . The spray-array  2  is ideally sized between 45 cm square and/or 35 cm by 60 cm rectangular. Here, the dimensions of the spray-array  2  and the spray-table  3  denotes the length and the width of the spray-array  2  and the spray-table  3  on a horizontal plane. 
     The apparatus of the present invention also comprises a collection unit C. The collection unit C is placed at the lowest point of the spray extraction unit E below the gutter channel  42  of the run-off device  4 . The collection unit C comprises several screens  51  disposed one below each other. The water flowing out the run-off device  4  successively crosses the screens  51  in a vertical direction, driven by the gravity. Each screen  51  has a reduced pore size from the upper one to the lowest one. For example, an upper sieving screen  51   a  may have a pore sized of 220μ microns. Ideally, the pore size of the upper sieving screen is less than 250μ micrometers. The pore size of a second sieving screen  51   b , placed below the upper sieving screen  51   a , may be comprised between 200μ and 175μ micrometers. Ideally, the pore size of the second sieving screen  51   b  is around 190μ micrometers. The pore size of a third sieving screen  51   c , placed below the upper sieving screen  51   b , may be comprised between 175μ and 150μ micrometers. Ideally, the pore size of the third sieving screen  51   c  is around 160μ micrometers. The pore size of a fourth sieving screen  51   d , placed below the upper sieving screen  51   c , may be comprised between 150μ and 115μ micrometers. Ideally, the pore size of the fourth sieving screen  51   d  is around 120μ micrometers. The pore size of a fifth sieving screen  51   e , placed below the upper sieving screen  51   d , may be comprised between 110μ and 80μ micrometers. Ideally, the pore size of the fifth sieving screen  51   e  is around 90μ micrometers. The pore size of a sixth sieving screen  51   f , placed below the upper sieving screen  51   e , may be comprised between 80μ and 65μ micrometers. Ideally, the pore size of the sixth sieving screen  51   f  is around 73μ micrometers. The pore size of a seventh sieving screen  51   g , placed below the upper sieving screen  51   f , may be comprised between 65μ and 35μ micrometers. Ideally, the pore size of the seventh sieving screen  51   g  is around 45μ micrometers. The pore size of an eighth sieving screen  51   h , placed below the upper sieving screen  51   g , may be comprised between 35μ and 1.5μ micrometers. Ideally, the pore size of the eighth sieving screen  51   h  is around 25μ micrometers. The number of the sieving screens and their pore size may easily be tuned according to the size of the integer resin glands to be processed. The number of the sieving screen can be in particular comprised between 4 and 20 or more. 
     In one embodiment, the collection unit C comprises a frame  52   a , which is suspended below the gutter channel  42  by the means of collection unit links  55 . If suspended, the frame  52   a  may be suspended to the run-off device  4 , or to another part of the extraction unit E, or even to the ceiling. The frame  52   a  maintains several sieving screens one below each other, as shown in  FIG. 2 . The pore size of the sieving screens is reduced along the vertical water flow F. As the water flow crosses the screens the mesh selects out the diverse sizes of the integer glandular trichomes and retains those on the screens when they are larger than the pore size opening of the mesh. The glandular trichomes are thus retained all along the sieving screens placed in digressive pore size order, each screen will retain those integer glandular trichomes larger than its particular mesh opening. Those integer glandular trichomes being of smaller size are washed through the screen to be caught in a subsequent smaller screen. The final screen may have a mesh size of only 15μ micrometers, to note the passage of water through the very fine mesh openings is much slower than the passage of water through the filter screens of larger mesh openings. Smaller than 45μ micrometers the glandular trichomes are probably partial and not integer. There is absolutely very little plant vegetation as contaminant present in the water. 
     The screen shape  52   a  may be square or round. It is advantageously hung in such a way as to remain open with a low point in the center. Such a hanging frame  52   a  is particularly useful when the collection unit C needs to be installed and removed regularly and carried to different places. It is also an advantage when the collection unit C is sold and sent to clients. A compact shape allows for easy travel and to reduce shipping costs. When the frame  52   a  is collapsible, the collection unit C can for example be suspended in such a way that the sieving screens  51  are straight above and below each other. 
     In another embodiment, the collection unit C comprises a rigid frame  52   b  standing below the gutter channel  42  of the extraction unit E. The frame  52   b  maintains several basins covered with sieving screens off-set in steps below each other. The frame  52   b  may be made of wood, metal or hard plastic or any other combination rigid materials. The basins, stretched with the filter screens, placed on the frame  52   b  are removable for an easy set up and adjustment of the flow. Each basin  53  has a sieving screen stretched over it, the bottom of which is provided with a hole  54 . With a flat base basin, it can also be tilted to focus the flow from the hole on its edge, as shown in  FIG. 3 , the basin is inclined on the cascade step. In this way, the water flow forms a cascade wherein the sieving screens  51  are offset from each other. The integer glandular trhichomes are thus retained on the top of all the sieving screens the pore size of which is smaller than the size of the glandular trichomes collected. Any dust, small broken glandular trichomes or impurities being of smaller size are washed off through the screen. 
     Whether the collection unit C is suspended or comprises a standing frame  52   b , it can be optionally embedded in a refrigerated work area, not shown, in such a way that the water does not warm up, or does not significantly warm up, during the extraction, isolation and collection process. 
     The spray-array  2 , spray table  3 , the run-off device  4  of the extraction unit E, and the sieving screens of the collection unit C, are thus arranged each one below the other, so as to allow a fast cascade process, wherein the glandular trichomes rich water successively crosses the meshed surfaces having progressively reduced hole size, in a vertical or substantially vertical flow F. The water flow F is preferably comprised between 0.8 and 1.5 liters per second. Filter screens with mesh openings below 80μ micrometers might need more surface area to maintain a smooth flow. 
     For a batch process, a given amount of fresh, unsprayed, glandular trichomes bearing raw plant materials may be placed on the spray-table  3  at the beginning of the ten-minute spray extraction, isolation and collection process and wherein the material is washed out before initiating another batch of plant materials. Alternatively, the spray-table  3  may be replaced by a porous conveyor belt dispatching raw plant materials and slowly moving the plant material under the nozzles  21 . 
     The purified and size isolated resin may be collected on the tops of the sieving screens of the collection unit C after just a few seconds, for a better preserved integer resin gland it is better to remove the collected glandular trichomes from the ongoing flow of water coming down from the spray extraction table  3  above. The rapid cascade and removal from the cold water reduces the dissolution of soluble components and thus provides a high quality isolated product. In particular, the water-soluble terpenes are preserved within the isolated integer resin glands. 
     After the water has passed through the cascade of the collection unit C the water may then be collected for further treatment, or simply sent to the drain. 
     The present invention also encompasses a kit comprising one or both of the extraction unit E and the collection unit C. In particular, a kit according to the present invention may comprise a spray-array  2 , a spray-table  3 , a run-off device  4 , and a collection unit C, as described here before. The spray-array  2  is provided with a fixation means  7  so as to be suspended. The input I of the kits manifold  28  can easily be connected to a cold-water source and a delivery system able to channel an adequate amount of water at the prescribed temperature and pressure. The spray-table  3  and the run-off device  4  in the kit of the present invention are both available with their optional suspension means  33  and  43 . 
     After the process the collected integer glandular trichomes resin can be frozen or stored at low temperature. 
     The purification process according to the present invention comprises the following steps:
         a) Placing the resin rich plant material to be worked on an extraction unit E, comprising a spray-table  3 , provided with a porous screen  32 . The size of the openings of the porous screen  32  is higher than the size of the targeted integer glandular trichomes to be collected. The hole size of the screen  32  of the spray-table  3  is around 250 micrometers.   b) Directing at least one cold pressurized water jet toward the resin rich plant material, so as to spray off and remove with water the integer resin glands from the material spread across the spray-table  3 .   c) Collecting the removed glandular trichomes suspended in the water flowing through the porous screen  32  of the spray-table  3  and onto a non-porous run-off device  4 , placed directly below the spray-table  3 .   d) Directing the water flow, comprising the resin glands from the run-off device  4 , to a collection unit C, comprising several sieving screens  51  positioned horizontally one below the other, in such a way that the flowing stream of resin rich water successively crosses the sieving screens  51 , descending by gravity in just a few seconds through the sieving unit  5 .   e) Collecting the purified glandular trichomes captured on those sieving screens having a mesh opening which is smaller than the size of the integer glandular trichomes.       

     The collection process may be performed using the arrangement described herein, or using a different cascading arrangement, provided that several sieving screens of progressively reduced pore size are used. One or more of the process steps may be automated. A continuous process may be set up using a porous conveyor belt instead of the spray-table  3 . Also, the collection and removal of the purified glandular trichomes from the various sized screens of the sieving unit may be automated by regularly swipe scratching off to the side, or washing off to the side with a water jet, the resinous glands collected on the sieving screens. 
     An illustrative example is described here below: 
     A spray-table  3  of approximately 3 square meters is used, stretched with a single piece of 250 micrometers opening nylon mesh. For one batch 500 liters of 2.5 bar pressurized cold water at a temperature of about 0.5° C. is sprayed for ten minutes over 4000 grams of loose dried flowers free from wood, dispatched on the spray-table  3 . Half way through the batch, after four to five minutes or 250 liters of water, the operator stops spray flow and the half processed plant materials are turned over with a soft plastic rake, requiring about one minute, and then sprayed again for four to five minutes by another 250 liters of pressurized cold water. When this batch process is repeated 4 times with 4000 grams of dry plant material in each batch, this process allows the operator of the spray levels 2 and 3 to purify 16 kilograms of dry plant material in roughly one hour. Below the spray levels 2 and 3 the operator at the purification and collection level 5 can collect 1600 to 2400 grains of glandular trichomes in one hour.