A SYSTEM FOR CONTROLLING LABORATORY SAMPLE TEMPERATURE AND A THERMAL TRAY FOR USE IN SUCH SYSTEM

Abstract: A system (10) for controlling the temperature of a laboratory sample is shown to include a thermal support tray (12) having a body formed from thermally conductive material and tubing (50) disposed within the body (12). A pair of couplers (40, 42) connects the input end and the output end of the tubing to a fluid control unit (14). The control unit maintains the temperature of a fluid at a desired level and circulates the fluid through the couplers and the tubing, controlling the temperature of the laboratory sample. It is preferred for the thermally conductive material to be non-magnetic material such as aluminum. A cavity (38) is formed in the body, shaped to receive either a beaker or a peri dish. An outer coating is affixed to the tray and is preferably a powder coating.

Description: A SYSTEM FOR CONTROLLING LABORATORY SAMPLE TEMPERATURE AND A THERMAL TRAY FOR USE IN SUCH SYSTEM Field of the Invention This invention relates generally to the systems, devices and methods used in a laboratory setting for controlling the temperature of samples or specimens being processed or analyzed. In particular, the invention relates to apparatus for maintaining the temperature of a laboratory sample during processing, for example while the sample is being processed in the vented hood of a clean room. Background of the Invention In the laboratory, particularly biomedical research laboratories, many protocols for research and analysis require that samples be maintained at precise and adjustable temperatures. For example, certain experimental reactions require incubations at cool temperatures. Biological samples generally must be maintained at temperatures of 0°C or below, in order to prevent spoiling or degradation. Harvesting and manipulation of biological materials can also require rapid placement and prolonged maintenance at very cold temperatures. In the tissue culture setting, biological samples must also be maintained in an uncontaminated state. For example, the tissue or cells from a mammalian source must not be contaminated with microorganisms which are found in the air and on surfaces of objects in the laboratory. The best type of sample temperature control system would allow the researcher to precisely choose and regulate the temperature at which a sample is maintained, without compromising sterility of the sample and without interfering with ease of sample manipulation. One of the simplest means of achieving a cooling or chilling environment for a sample in the laboratory is the ice bucket. Samples and solutions, placed in protective tubes and containers, can be maintained at temperatures near 0°C when plunged into crushed ice. However, as the ice begins to melt, tubes are subject to sinking, floating around, or otherwise toppling over. Overlying supports and racks placed in the ice bucket can help prevent the loss of tubes and containers in the melting ice, but can be cumbersome. Moreover, ice incubations are always limited in temperature choice. The operator cannot choose temperature with precision, nor can temperatures below 0°C be selected. As the ice melts, the temperature rises toward ambient temperature, until the samples are in an ambient temperature water bath. Thus, the standard ice bucket method of cold incubation must be reserved only for processing involving brief durations, where thermal accuracy and temperature choice are not critical. Certain procedures , such as the mincing of biological tissues , are carried out in shallow, sterile Petri dishes. Maintaining the integrity of the proteins and other cellular contents requires the mincing to be done at 0°C. This has traditionally been accomplished by placing the Petri dish on a bed of crushed ice. However, crushed ice has a generally bumpy surface, which can result in the Petri dish tipping over during the chopping and mincing process. At a minimum, the bed of crushed ice presents an uneven and unstable support surface for the mincing operation. A further hazard in this methodology is the possibility that a piece of the crushed ice may bounce into the dish, resulting in the contamination of the sample. This can occur because the person mincing the tissue is pushing down on the Petri dish with a tool, and the mincing force will shift the dish underlying pieces of ice. Consequently, a need exists for a chilling surface for manipulations using a Petri dish which has a secure flat surface. Such a surface would allow the dish to remain basically horizontal during the mincing operation. Additionally, such a surface would hold its shape against the pressure generated by the cutting, chopping, or scraping instruments that are being moved around in the dish. Other procedures carried out on tissue samples involve constant stirring, under chilling conditions , of sterile solutions in beakers . If such cell or tissue extracts were incubated in a bucket of crushed ice, the combined thickness of the ice and the insulating bucket would make it impractical, if not impossible, to use a magnetic stir plate to direct automatic stirring of the solution. Consequently, a need exists for a chilling surface which is also capable of use in conjunction with a magnetic stir plate. Furthermore, in the tissue culture setting, where cells and tissues must be manipulated under conditions of sterility, the ice bucket is a source of contamination. The ice bucket, like other equipment in the laboratory, may receive spills and splatters from other materials. Accordingly, any equipment to be used in a culture hood or biosafety cabinet must be easily cleaned or sanitized of foreign materials and organisms. Typically, ice buckets are made of materials such as styrofoam, polyvinyl chloride foam, and polyurethane-skinned foam, which are not easily sanitized or sterilized. Thus, the introduction of an ice bucket into a biosafety hood environment could compromise sterility. Consequently, a need exists for a chilling surface which is capable of being easily sanitized or sterilized. Baths of water or other fluids can be precisely chilled to temperatures below ambient and well below 0°C. using a variety of electrically powered refrigerating devices. However, a fluid bath is not practical for working under sterile conditions in a tissue culture hood, and could not be used for work with Petri dishes. A researcher might work with samples in a cold room, but this necessitates thermal protection for the worker, and is also impractical for sterile tissue culture work. Dry blocks capable of cooling and heating samples have been used in the laboratory. Such blocks provide flat surfaces for dishes and can be formed with recesses to receive sample tubes. Additionally, such blocks can be temperature regulated to -19°C (-2°F). However, such blocks operate via Peltier thermoelectric heating technology. This cooling technology requires such devices to be plugged into an electrical outlet, posing electrical hazards to the user of a typically metal biosafety hood. Furthermore, such devices do not permit use with a magnetic stirrer, because of their configuration. Consequently, a need still exists for a dry, sanitizable surface that can evenly and controllably chill samples (in containers) placed in contact with the surface, that can operate in conjunction with a magnetic stirrer and will not introduce the risk of electric shock. Summary of the Invention The present invention is directed to a system for controlling the temperature of a laboratory sample. The system includes a thermal support tray having a body formed from thermally conductive material and tubing disposed within the body . A pair of couplers connects the input end and the output end of the tubing to a fluid control unit. The control unit maintains the temperature of a fluid at a desired level and circulates the fluid through the couplers and the tubing, controlling the temperature of the laboratory sample. It is preferred for the thermally conductive material to be non-magnetic material such as aluminum. A cavity is formed in the body, shaped to receive a beaker. Alternatively, the cavity could be dimensioned to receive a petri dish. However, it is envisioned that petri dishes will be used by placing them on the flat tp surface formed on the body. An outer coating is affixed to the tray and is preferably a powder coating. It is preferred for the tubing to be formed from stainless steel and for the fluid to be substantially a glycol solution. It is also preferred for the fluid control unit to include a compressor operative to cool the glycol solution to a desired temperature and a pump to circulate the glycol solution through the tubing. It is further preferred to attach a temperature sensor to the body for providing an indication of temperature and for maintaining the temperature of the fluid in relation to the sensed temperature. Brief Description of the Drawings The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments that are presently preferred, it being understood, however, that the invention is not limited to the specific apparatus, system, and instrumentalities disclosed. In the drawings: Figure 1 is a diagrammatic view of a system for controlling the temperature of a laboratory sample constructed in accordance with the present invention; Figure 2 is a perspective view of a thermal tray depicted diagrammatical ly in Fig. 1; Figure 3 is a section view taken along the line 3-3 shown in Fig. 2; Figure 4 is a section view taken along the line 4-4 shown in Fig. 2; and Figure 5 is an alternate embodiment of a thermal holder constructed in accordance with the present invention. Detailed Description of Preferred Embodiments A system for controlling laboratory sample temperature and a thermal tray for use in such system that solves the above-mentioned problems, and provides other beneficial features in accordance with the presently preferred exemplary embodiments of the invention will be described below with reference to Figures 1-5. The description given herein with respect to the figures is for explanatory purposes only and is not intended in any way to limit the scope of the invention. Throughout the following detailed description similar reference numbers refer to similar elements in all the figures. As shown in Figure 1, the present invention is directed to a system 10 for controlling the temperature of a laboratory sample (not shown) and a thermal tray 12 for use in such system. In the operation, a fluid control unit 14 maintains the temperature of a fluid such as propylene glycol to some desired level, for example 0°C. It is noted that while the embodiment shown in Fig. 1 is described in relation to maintaining a sample at a relatively cool temperature of 0°C, the invention is not so limited. It is also within the scope of the invention to maintain the temperature of a sample at either cooler temperatures , for example as low as -100° F (-73.3 C) or at a elevated temperatures, for example as high as 200°F (93.3 ° C) Control unit 14 includes a compressor 16 which acts to remove heat from the glycol bath. A temperature sensor 18 senses the temperature of the FDA approved propylene glycol and generates a temperature signal representative of the glycol temperature. Control unit 14 controls the operation of compressor 16 in response to the temperature signal. In the preferred embodiment, control unit 14 is a glycol power pack unit or a glycol recirculating chiller, which units are known, but which are believed not to have been used previously in the manner described herein, i.e. , not to have been used to chill a thermal tray. A pump 20 operates to circulate the glycol solution through a fluid circuit of supply tubing 22 and return tubing 24. The tubing is arranged to provide cooled glycol through wall 26 into clean room 28. A vented hood 30 is positioned within clean room 28. Thermal tray 12 is positioned within the confines of vented hood 30 and is connected to tubing 22 and 24. As will be described in greater detail herein, glycol fluid is circulated through thermal tray 12 and returned to control unit 14. It is noted that no thermal tray is attached at positions 32 and 34. Instead, tubing 22 is directly connected to tubing 24, thereby permitting the glycol to circulate back to control unit 14. The temperature of the glycol can be accurately maintained at a desired level because it is constantly being circulated back to control unit 14. Referring now to Fig. 2, thermal tray 12 will be described in more detail. Thermal tray 12 is formed from thermally conductive material, preferably aluminum, and is rectilinear ly shaped. It is especially preferred for tray 12 to be formed from No. 713 grade aluminum, also known as tenzoly. It is noted that the particular shape of tray 12 depicted in Fig. 2 is not intended to limit the scope of the invention. Tray 12 can be formed into any one of a myriad of shapes without departing from the scope of the invention. Tray 12 includes a flat top surface 36. As will be appreciated below, the entire surface of tray 12 operates to control the temperature of anything which is placed thereon. For example, if a petri dish containing a sample were placed on surface 36, the sample would be cooled. Additionally, since tray 12 is formed from thermally conductive metal material, is provides significant support for mincing processes. A cavity 38 is formed in the surface of tray 12. It is preferred for the dimensions of cavity 38 to be such that a beaker can be easily placed therein. It is noted that by forming a cavity which extends through the thickness of tray 12 and by forming the body of tray 12 from aluminum, a magnetic stirring device can be easily used to stir the contents of a beaker placed within cavity 38. A pair of couplers 40 and 42 are connected to one side of tray 12. As will be explained in connection with Figs. 3 and 4, a length of tubing is disposed within the body of tray 12 through which the glycol is circulated. Couplers 40 and 42 serve to couple the tubing internal to tray 12 to supply and return tubing 22 and 24, respectively. It is noted that no particular coupler design is necessary in order for tray 12 to operate as described. Any coupler design capable of connecting tubing 22 and 24 and capable of operating under the temperature conditions imposed by the fluid being circulated will suffice. Accordingly, no additional details are given herein of couplers 40 and 42. A pair of handles 44 and 46 are also provided on opposite sides of tray 12. As will be appreciated from the description herein, tray 12 being formed from metal can be heavy. Handles 44 and 46 serve to make tray 12 easier to manipulate. Moreover, cavity 38 does not extend completely through tray 12 to the underside (not shown). In this embodiment, the underside is formed as a continuous flat surface. Since tray 12 is formed from thermally conductive material, the underside is also capable of controlling temperature. Accordingly, if it is desireable to process samples on a continuously flat surface, using handles 44 and 46, one can turn tray 12 over exposing the underside as a working surface. Finally, it is noted that the exterior surface of tray 12 is covered with a coating 48. In the preferred embodiment, coating 48 is a powder coating. It is especially preferred for the powder coating to be CORNEL™ FDA white U 1585-1 1042 available from Rohm and Haas, Inc. of Philadelphia, Pennsylvania. Such a coating can be electrostatically applied to tray 12 in a conventional manner. In order to enhance such a powder coating application and for additional safety, the edges of tray 12 are all rounded. It is known that when powder coating is electrostatically applied to sharp edges, the coating can become unacceptably thin along the edge. By powder coating the exterior surface of tray 12, after it has been used, it can be uncoupled from tubing 22 and 24 and itself processed. The durability of the preferred coating is such that tray 12 can be sanitized using liquid sanitizers. All traces of sanitizer can then be removed by baking tray 12 at a temperature as high as 200°F (93.3 C). Such a sanitization/sterilization process is highly desirable. Referring now to Figs. 3 and 4, the inner workings of tray 12 will be described in greater detail. A length of tubing 50 is disposed within the body of tray 12. It is especially preferred for tubing 50 to be 3/8 inch outside diameter, 316L stainless steel tubing. In one embodiment, tubing 50 is approximately 9 feet long and weighs approximately 1.35 lbs. The body of tray 12, in that embodiment, is formed from approximately 18.15 lbs of aluminum. It has been discovered that the ratio of 2.02 inches of tubing 50 for each pound of aluminum results in very good thermal transfer characteristics. It has also been discovered that when this ratio is maintained and tubing 50 is arranged in the pattern depicted in Figs. 3 and 4, a relatively consistent temperature gradient is achieved across the surface of tray 12. As shown in Fig. 4, 3 coils of tubing 50 extend around cavity 38. It is noted that tray 12 is formed by positioning tubing 50 in a desired pattern and orientation within a mold and then overmolding the tubing with molten aluminum. In this manner, tubing 50 is disposed within the body of tray 12. Referring back to Fig. 1 , another embodiment of the invention includes the attachment of a temperature sensor 52 to tray 12. Sensor 52 senses the temperature of tray 12 and generates a temperature signal representative of the sensed temperature. The temperature signal is provided to control unit 14, which in turn controls the temperature of the fluid in response to the temperature signal from sensor 52. Referring now to Fig. 5, an alternate embodiment of tray 12 is shown. In Fig. 5, a container 54 is depicted. Container 54 has a cavity 56 formed therein. It is noted that cavity 56 is shaped especially for receiving test tubes and the like. A length of tubing 58 is coiled around cavity 56. Fluid maintained at a desired temperature is circulated through tubing 58 by means of couplers 60 and 62. A removable liner 64 is positioned within cavity 56. In certain procedures it is necessary to place a sample within a test tube and physically mash the sample using a plunger like device. It is desirable for such mashing operation to occur at selected temperatures, for example at 0°C. Container 54 permits this process to take place. Occasionally, during the mashing operation, the test tube breaks. If such a situation occurs in container 54, one need only remove liner 56, in order to remove any broken glass. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims: Claims What is Claimed is: 1. A system for controlling the temperature of a laboratory sample, said system comprising: a thermal support tray, said tray comprising a body formed from thermally conductive material for supporting said sample, and tubing, disposed within said body, said tubing having an input end and an output end; a pair of couplers, wherein a coupler is connected to said input end and said output end of said tubing; and a fluid control unit, in fluid communication with said pair of couplers , wherein said unit maintains the temperature of a fluid at a desired level and wherein said unit circulates said fluid through said couplers and said tubing, wherein the temperature of said laboratory sample is controlled. 2. The system of Claim 1, wherein said thermally conductive material comprises non-magnetic material. 3. The system of Claim 2 , wherein said non-magnetic material comprises aluminum. 4. The system of Claim 1 , wherein a cavity is formed in said body, said cavity being shaped to receive a beaker. 5. The system of Claim 1 , wherein a cavity is formed in said body, said cavity being shaped to receive a Petri dish. 6. The system of claim 1 , further comprising an outer coating affixed to said body. 7. The system of Claim 6, wherein said outer coating comprises a powder coating. 8. The system of Claim 1 , wherein said tubing comprises stainless steel . 9. The system of Claim 1, wherein said fluid comprises a propylene glycol solution. 10. The system of Claim 9, wherein said fluid control unit comprises a compressor operative to cool said glycol solution to a desired temperature and a pump to circulate said glycol solution through said tubing. 11. The system of Claim 1 , further comprising a temperature sensor attached to said body for providing an indication of the temperature of said body. 12. The system of Claim 11 , wherein said temperature sensor comprises an electronic temperature sensor for generating a temperature signal representative of the temperature of said body, wherein said temperature sensor is electrically connected to said fluid control unit and wherein the temperature of said fluid is maintained in response to said temperature signal. 13. Apparatus for use in a system for controlling the temperature of a laboratory sample, said apparatus comprising: a body formed from thermally conductive material adapted for the reception of said sample; and tubing, disposed within said body, said tubing having an input end and an output end, wherein when fluid having a desired temperature is circulated through said tubing the temperature of said laboratory sample is controlled. 14. The apparatus of Claim 13, wherein said thermally conductive material comprises non-magnetic material. 15. The apparatus of Claim 14, wherein said non-magnetic material comprises aluminum. 16. The apparatus of Claim 13, wherein said cavity formed in said body comprises a cavity formed to receive a beaker. 17. The apparatus of Claim 13, wherein said cavity formed in said body comprises a cavity formed to receive a Petri dish. 18. The apparatus of claim 13, further comprising an outer coating affixed to said body. 19. The apparatus of Claim 18, wherein said outer coating comprises a powder coating. 20. The apparatus of Claim 13, wherein said tubing comprises stainless steel. 21. The apparatus of Claim 13, further comprising handles attached to said body.

Inventors: LINEHAN KENNETH J, LINEHAN, KENNETH, J.
Applicants: MECOUR TEMPERATURE CONTROL LLC, MECOUR TEMPERATURE CONTROL, LLC
Application year: 2000
Main classification: G05D23
IPC codes: B01L7, F25B49, F25D17, F25D31, G05D23