Title of Invention

GEL DRYER AND PROCESS OF DRYING GELS

Abstract

Gel Dryer comprising a vacuum distribution block support base attached to a top unit by a hinge, continuous or discontinuous shelf provided on size of said vacuum distribution block support base, a vacuum distribution block rests on said shelves to provide a space under said shelves to collect excess fuel that flows over the said vacuum distribution blocks, the said top unit includes a heating element attached to a blackened thermally conductive metal sheet, a temperature sensing device fitted to said blackened sheet to control the heating element, the said heating element is thermally isolated from the cover of the said top unit by insulating material, and the controller for said temperature sensing device, timers and switching controller being provided in a control housing of said top unit.

Full Text

FORM 2 THE PATENTS ACT, 1970 COMPLETE SPECIFICATION Section 10 "Gel dryer and process of drying gels" Dr. Bosco Maria Agnelo Henriques, an Indian national, of 1-21 Stone Castle, Mandalpeshwar, Borivili(West), Mumbai-400103, India The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed: Field of Invention This invention relates to a gel dryer and process of drying gels. BACKGROUND Gel-dryers are used to exsiccate gels after electrophoresis is complete, so that they can be preserved as records or for future analysis. Dried gels can be scanned when the biomolecules in the stained bands need to be quantitated or images reproduced. Sharper bands are obtained when autoradiographs are prepared using dried gels. Gels can be dried at a) Room temperature, b) At higher temperatures in an oven or c) In Hypo-baro-thermal gel-dryers. I During the process of drying, gels contract in all dimensions. Successful drying of gels requires that the process of exsiccation be achieved without allowing the gel to shrink (in the X, Y plane), crack or get distorted. The bands get distorted in gels that shrink during the drying process and this renders them useless for further analysis. While attempting to dry gels at room temperature or in an oven special care needs to be taken to prevent them from shrinking. In order to prevent shrinkage, the gels are sandwiched between two tightly drawn sheets of cellophane/gelatin paper. These sheets need to be kept taut by means of a frame. Problem: This method is not very user-friendly since considerable skill is involved in ensuring that the cellophane paper does not get crinkled and air bubbles are not entrapped in the sandwich. (Entrapped air bubbles will cause the gels to crack.) Gel drying by these methods could take several days at room temperature and many hours in the oven. Large gels often cannot be dried by this method, as it is difficult to keep the required length of cellophane sheet taut. II Hypo-baro-thermal gel-dryers are designed for quicker drying of gels and are based on the principle that water evaporates faster at lower pressures and higher temperatures. In the dryer the gel is held firmly in place to prevent shrinkage and distortion, while an air suction pump and induced heating are used to dry the gel quickly. Gels dried by this method are:- • Sandwiched between one porous (blotting paper or cellophane) and one thin transparent plastic sheet to form a gel sandwich. • The gel-sandwich is assembled on a perforated metal/ porous plastic sheet that lies on a grooved metal block that is fixed in and is of similar area of the base of the gel dryer. • A heat-tolerant resilient sheet that is large enough to cover the entire surface of the metal block is placed over the gel sandwich. This sheet acts as a vacuum seal and holds the gel in place when a vacuum is applied thereby allowing the gel to thin out but not shrink. • Grooves are carved in the metal block to drain the air/vapour from the undersurface of the perforated metal/ porous plastic sheet. The grooves lead into a duct that connects to an air-suction pump through a connector and tubing. • The rate at which the temperature rises has to be controlled in the initial stages to prevent the gels from cracking. Problems: • Under vacuum the perforated metal sheet gets apposed to the metal block and hinders the removal of the vapours that accumulate below the surface of the sheet. This slows down the drying process, results in uneven drying and often causes the gel to crack. • In prior-art gel dryers, the control circuitry is installed in the lower portion of the dryer, while the heating elements and sensors are located either in the lower or upper portions. While assembling the gel sandwich it is necessary to pour some water or glycerol solution, on the gel. This is essential to prevent air bubbles from getting entrapped within the sandwich. Spillage of this liquid onto the base of the dryer can damage the circuitry. • The gradual rate at which the temperature should rise is important in the initial stages of drying the gel. This has to be achieved by turning the heater on and off (manually) at selected intervals. Dryers that are fitted with microprocessors, facilitate this task by providing automatic control. The use of microprocessors increases the cost and frailty of the apparatus. • The grooved metal block is of a fixed size. When multiple gels have to be dried, they have to be dried simultaneously or sequentially, as the drying process cannot be interrupted until the gel is completely dry. ne object of this invention is to avoid the above problems. achieve the said objective this invention provides a gel dryer comprising - a vacuum distribution block support base attached to a top unit of dryer by a hinge, - continuous or discontinuous shelf provided on size of said vacuum distribution block support base, - a vacuum distribution block rests on said shelves to provide a space under said shelves to collect excess fuel that flows over the said vacuum distribution blocks, - the said top unit includes a heating element attached to a blackened thermally conductive metal sheet, - a temperature sensing device fitted to said blackened sheet to control the heating element, - the said heating element is thermally isolated from the cover of the said top unit by insulating material, and - the controller for said temperature sensing device, timers and switching controller being provided in a control housing of said top unit. The said top unit is positioned above the vacuum distribution block such that a small and uniform air gap 2-10 mm. is maintained between the blackened thermally conductive metal sheet and the heat tolerant resilient sheet. The vacuum distribution block is made of either metal or temperature resistant plastic. The vacuum distribution block is sculpted to form a shallow depressed area and a ledge around the perimeter of said block. The inner edge of said ledge is chambered to prevent the resilient sheet that covers said block from tearing. The depth of said depressed area is 0.5-5 mm greater than the thickness of the perforated metal/heat tolerant porous plastic sheet that is to be placed in said depressed area. The top surface of the perforated/porous sheet will be lower than the surface of the ledge. The channels are trellised in the depressed area of the block to drain away air / vapour. Said shallow depressed area is further sculpted to leave a thin ridge along the boundaries of the channels to form cell in between the trellised channels. The notches are incised across said ridges to permit free flow of vapour from the cells into the channel and the ridges ensure that a gap is always maintained between the perforated metal / heat tolerant porous plastic sheet and vacuum distribution block. This invention further includes process of drying gels using gel dryer as claimed in proceeding claims comprising placing gel over the blotting paper avoiding entrapment of air bubbles under the gel, layering water/ glycerol solution over said gel and thereafter placing heat tolerant plastic sheet over the said gel, said blotting paper is placed on the perforated metal/heat tolerant porous plastic sheet, the said sandwitch is placed over the vacuum distribution block, the said vacuum distribution block is connected to a vapor trap and air suction pump to create vacuum causing the resilient sheet to adhere tightly to said perforated metal /heat tolerant porous plastic sheet holding said gel firmly in place and thereby allowing the gel to thin out but not shrink, the ridges of the vacuum distribution block ensure that a layer of water is retained in the cell and the depth of the notches in the ridges determines volume of water contained, switching on the heating elements in the top unit to evaporate the water from the gel, and the heat absorbed by the water in the cell dampens the rate of rise in temperature thereby heating of gel is gradual and prevents the gel from cracking The said air suction pump generates low pressure, and vapours are drawn to underside of the gel and passes through the porous sheet and is continuously sucked, the combined action of low pressure and heating dries the gel quickly. The depth of notches in the vacuum distribution block will determine the amount of water contained in each cell. The depth of said notches can be varied to increase and decrease the quantum of water in the cell. Th large volume of water in the cell will prolong the restraint on the rate of rise in temperature and vice-versa. The length of time during which the rate of rise in temperature is to be restrained is directly proportional to the gel thickness. The present invention will now be described with the accompanying drawings. Figure 1 shows the gel dryer according to this invention. Figure 2 shows section of vacuum distribution block according to this invention. Referring to the drawings the gel dryier consists of a vacuum-distribution-block support base (1) that is attached to a top unit (2) {lid like structure} by a hinge (not shown). Continuous or discontinuous shelves (3) are attached at a fixed height on the sides of the vacuum-distribution-block support base(l). The vacuum-distribution-block (4) rests on these shelves(3). The space under the shelves serves to collect any excess fluid that flows over the vacuum-distribution-block(4). The underside of the top unit (2) comprises of a heating element that is attached to a blackened thermally conductive metal sheet(6). This blackened sheet radiates heat to the gel that is being dried on the vacuum-distribution-block(4). A temperature-sensing device(not shown) such as a thermostat is fitted to the blackened sheet (6) to control the heating element. The heating element is thermally isolated from the cover of the top unit by insulating material such as glass wool. The controller for the temperature-sensing device and other controlling elements such as timers, switching controller are fitted in the control housing (5) of the top unit (2). Hence, any water/solution that spills while the gel is being assembled does not wet or affect any of the heating or control elements. The top unit (2) is positioned above the vacuum-distribution-block (4) such that a small and uniform air-gap (2-10 mm) is maintained between the blackened thermally conductive metal sheet and the heat-tolerant resilient sheet. The easily removable vacuum-distribution-block (4) is made of either metal or temperature resistant plastics (including thermosetting plastics and thermoplastics). The block is sculpted to form a shallow depressed area and a ledge (7) (of width 2-40 mm preferably 10 mm) around the perimeter of the block(4). The inner edge of this ledge is chamfered to prevent the resilient sheet that covers the block from tearing. The depth of this depressed area is 0.5-5mm, preferably 1mm, greater than the thickness of the perforated metal/ heat tolerant porous plastic sheet that is to be placed in this depressed area. The top surface of the perforated/porous sheet will always be lower than the surface of the ledge. Channels (8) are trellised in the depressed area of the block, to drain away air/vapour. The channels lead into a duct that connects to an air-suction pump (not shown) through a connector (9) and tubing. The shallow depressed area is further sculpted to leave a thin ridge (10) along the boundaries of the channels to form cells in between the trellised channels(8). Notches (11) are incised across the ridges (10) to permit free flow of the vapour from the cells (12) into the channels(8). The ridges (10) ensure that a gap is always maintained between the perforated metal/ heat tolerant porous plastic sheet and the vacuum-distribution-block. By preventing the perforated metal/heat tolerant porous plastic sheet (13) from getting apposed to the vacuum-distribution-block vapour from the entire undersurface of the gel can be collected. This improvement results in uniform and faster drying of the gel and minimizes the chances of cracking. A perforated metal/ heat tolerant porous plastic sheet(13), which is of the same size as the depressed area, is placed over the ridges (10). A thin (approx 1mm) heat-tolerant resilient sheet (preferably of translucent silicone rubber) that is larger than the depressed area, preferably the size of the vacuum-distribution-block, is placed over the perforated metal/ heat tolerant porous plastic sheet. This sheet acts as a vacuum seal when the duct is connected to the air-suction pump. The process of drying gels according to this invention is as follows: • A wet blotting/cellophane paper (14) is placed on the perforated metal/ heat tolerant porous plastic sheet (13) that lies in the depressed area of the vacuum-distribution-block(4). Water/glycerol solution is layered over the moist paper till the solution covers the paper. The gel (15) is placed over the paper (14) avoiding entrapment of air-bubbles under the gel. Some water/glycerol solution is layered over the gel and then a transparent heat-tolerant plastic sheet is placed over it. Entrapment of air-bubbles is avoided. • The heat-tolerant resilient sheet (16) is placed over the vacuum-distribution- block (4) so as to cover the gel sandwich. • The connector (9)is attached to a water-trap (with the help of tubing) that is in turn connected to a vapour-trap that in turn is connected to an air-suction pump(not shown). The air-suction pump is then turned on. The excess fluid collects in the water-trap. Under the influence of the applied suction, a partial vacuum is created causing the resilient sheet to adhere tightly to the perforated metal/porous plastic sheet(13), holding the gel (15)firmly in place and thereby allowing the gel to thin out but not shrink. The ridges ensure that a layer of water is retained in the cells (12) and the depth of the notches (11) in the ridges (10)determines volume of water contained. • The heating element is turned on. The heat causes the water from the gel and from the underlying cell to evaporate. The heat absorbed by the water in the cell dampens the rate of rise in temperature. The heating of the gel is therefore gradual and this prevents it from cracking. This evaporating layer of water obviates the need of user attention or a microprocessor in controlling the rate of rise in temperature. • The depth of the notches will determine the amount of water contained in each cell. The depth of the notches can be varied (in different models) to increase or decrease the quantum of water contained in the cells. A larger volume of water in the cells will prolong the restraint on the rate of rise in temperature and vice versa. The length of time during which the rate of rise in temperature is to be restrained is directly proportional to the gel thickness. Hence, this feature permits the user to obtain optimally designed sculpted metal vacuum manifold for different thickness of gels. The design of notched ridges along the channel edges provides a structural solution over an electronic one by obviating the need for user attention or use of microprocessors for successful drying of gels. It also ensures that the instrument is rugged and economical. • On account of the low pressure generated by use of an air-suction pump the vapour is drawn to the underside of the gel whence it passes through the porous sheet, and is continuously sucked out by means of the air-suction pump. The combined action of low-pressure and heating dries the gel quickly. • The removable nature of the vacuum-distribution-block also allows blocks of different notch depths on the ridges (optimized for different gel thickness) to be interchangeably used. • The removable nature of the vacuum-distribution-block (4) also enables multiple smaller vacuum-distribution-blocks to be placed in the vacuum- distribution-block support base. A firm panel would have to be placed on the shelves and the vacuum-distribution-blocks placed on this panel. As a result of this feature, different sizes of sculpted metal blocks each with it's own connector and covering resilient sheet can be placed in the support base. Smaller gels that need to be dried can be assembled on separate vacuum- distribution-blocks and introduced or removed independently of each other without disturbing other gels already in the process of being dried. We Claim: 1. Gel Dryer comprising: - a vacuum distribution block support base attached to a top unit of dryer by a hinge, - continuous or discontinuous shelf provided on side of said vacuum distribution block support base, - a vacuum distribution block with depressed areas rests on said shelves to provide a space under said shelves to collect excess fuel that flows over the said vacuum distribution blocks, - the said top unit includes a heating element attached to a blackened thermally conductive metal sheet, - a temperature sensing device fitted to said blackened sheet to control the heating element, - the said heating element is thermally isolated from the cover of the said top unit by insulating material, and - the controller for said temperature sensing device, timers and switching controller in a control housing of said top unit. 2. Gel dryer as claimed in claim 1 wherein said top unit is positioned above the vacuum distribution block such that an air gap of 2-10 mm. is maintained between the blackened thermally conductive metal sheet and the heat tolerant resilient sheet. 3. Gel dryer as claimed in claim 1 wherein vacuum distribution block is made of either metal or temperature resistant plastic. 4. Gel dryer as claimed in claim 3 wherein said vacuum distribution block is sculpted to form a shallow depressed area and a ledge around the perimeter of said block. 5. Gel dryer as claimed in claim 4 wherein inner edge of said ledge is chambered to prevent the resilient sheet that covers said block from tearing. 6. Gel dryer as claimed in claim 4 wherein depth of said depressed area is 0.5-5 mm greater than the thickness of the perforated metal/heat tolerant porous plastic sheet that is to be placed in said depressed area. 7. Gel dryer as claimed in claim 6 wherein top surface of the perforated/porous sheet will be lower than the surface of the ledge. 8. Gel dryer as claimed in claim 4 wherein channels are trellised in the depressed area of the block to drain away air / vapour. 9. Gel dryer as claimed in claim 8 wherein said channel leads into a duct that connects to an air succession pump through a connector and tubing. 10. Gel dryer as claimed in claim 4 wherein said shallow depressed area is further sculpted to leave a thin ridge along the boundaries of the channels to form cell in between the trellised channels. 11. Gel dryer as claimed in claim 10 wherein notches are incised across said ridges to permit free flow of vapour from the cells into the channel and to ensure that a gap is always maintained between the perforated metal / heat tolerant porous plastic sheet and vacuum distribution block. 12. A process of drying gels using gel dryer as claimed in preceeding claims comprising: - placing gel over the blotting paper avoiding entrapment of air bubbles under the gel, - layering water/ glycerol solution over said gel and thereafter placing heat tolerant plastic sheet over the said gel, - said blotting paper is placed on the perforated metal/heat tolerant porous plastic sheet to form a sandwitch, - the said sandwitch is placed over the vacuum distribution block, - the said vacuum distribution block is connected to a vapor trap and air suction pump to create vacuum causing the resilient sheet to adhere tightly to said perforated metal /heat tolerant porous plastic sheet holding said gel firmly in place and thereby allowing the gel to thin out but not shrink, - switching on the heating elements in the top unit to evaporate the water from the gel, - ridges to permit free flow of vapour from the cells into the channel and to ensure that a gap is always maintained between the perforated metal / heat tolerant porous plastic sheet and vacuum distribution block. 13. A process as claimed in claim 12 wherein said air suction pump generates low pressure, and vapours are drawn to underside of the gel and passes through the porous sheet and is continuously sucked, the combined action of low pressure and heating dries the gel quickly. 14. A process as claimed in claim 14 wherein the depth of said notches can be varied to increase and decrease the quantum of water in the cell. 15. A process as claimed in claim 12 wherein the large volume of water in the cell will prolong the restraint on the rate of rise in temperature and vice-versa. 16. A process as claimed in claim 12 wherein the length of time during which the rate of rise in temperature is to be restrained is directly proportional to the gel thickness. 17. A gel dryer substantially as herein described with reference to the accompanying drawings. 18. A process of dyring gels using gel dryer substantially as herein described with reference to the accompanying drawings. Dated this 14th day of August, 2001 Archana Shanker Of Anand and Anand Advocates Agents for the Applicants

Documents:

455-mum-2000-abstract(6-5-2005).doc

455-mum-2000-abstract(6-5-2005).pdf

455-mum-2000-cancelled pages(6-5-2005).pdf

455-mum-2000-claims(granted)-(6-5-2005).doc

455-mum-2000-claims(granted)-(6-5-2005).pdf

455-mum-2000-correspondence(6-5-2005).pdf

455-mum-2000-correspondence(ipo)-(29-6-2007).pdf

455-mum-2000-drawing(6-5-2005).pdf

455-mum-2000-form 1(17-5-2000).pdf

455-mum-2000-form 1(23-6-2000).pdf

455-mum-2000-form 19(19-5-2004).pdf

455-mum-2000-form 2(granted)-(17-5-2000).doc

455-mum-2000-form 2(granted)-(6-5-2005).pdf

455-mum-2000-form 3(5-9-2001).pdf

455-mum-2000-form 4(16-8-2001).pdf

455-mum-2000-form 5(16-8-2001).pdf

455-mum-2000-other documents(19-5-2004).pdf

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