Waterless vessel heating system and method

• US 6,303,909 B1
• Filed: 06/23/2000
• Issued: 10/16/2001
• Est. Priority Date: 06/23/2000
• Status: Expired due to Term

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Varian Incorporated (Agilent Technologies, Inc.)
• Inventors: Fernando, C. J. Anthony, Swon, James E., Haw, Michael F.
• Primary Examiner(s): PELHAM, JOSEPH MOORE
• Application Number:
  US09/603,305
• Time in Patent Office: 480 Days
• Field of Search: 219/385, 219/386, 219/429, 219/436, 219/528, 219/549, 366/143, 422/68.1, 422/82.12, 738/66
• US Class Current: 219/429
• CPC Class Codes: B01F 21/00 Dissolving separating by dissolving B01D; dissolving to effect cooling F25D5/00
• CPC Class Codes: B01F 21/10 using driven stirrers
• CPC Class Codes: B01F 2101/23 Mixing of laboratory samples e.g. in preparation of analysing or testing properties of materials
• CPC Class Codes: B01J 19/0013 Controlling the temperature of the process
• CPC Class Codes: B01J 2219/00011 Laboratory-scale plants
• CPC Class Codes: B01J 2219/00038 Processes in parallel
• CPC Class Codes: B01J 2219/00063 of the reactants
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/002 inside the reactor
• CPC Class Codes: B01J 2219/00213 Fixed parameter value
• CPC Class Codes: B01J 2219/00238 of the heat exchange system
• CPC Class Codes: B01L 2300/1805 Conductive heating, heat from thermostatted solids is conducted to receptacles, e.g. heating plates, blocks
• CPC Class Codes: B01L 7/00 Heating or cooling apparatus autoclaves B01J3/04; Heat insulating devices
• CPC Class Codes: G01N 13/00 Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects scanning-probe techniques or apparatus G01Q
• CPC Class Codes: G01N 2013/006 Dissolution of tablets or the like
• CPC Class Codes: G01N 33/15 Medicinal preparations ; Physical properties thereof, e.g. dissolubility drug screening with animal cells G01N33/5008
• CPC Class Codes: H05B 2203/005 using multiple resistive elements or resistive zones isolated from each other
• CPC Class Codes: H05B 2203/014 Heaters using resistive wires or cables not provided for in H05B3/54
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 2203/037 Heaters with zones of different power density
• CPC Class Codes: H05B 3/00 : Ohmic-resistance heating
• CPC Class Codes: H05B 3/34 : flexible, e.g. heating nets or webs
• CPC Class Codes: H05B 3/54 : flexible

Abstract

A dissolution testing system comprises a vessel plate on which a plurality of vessels are mounted. Each vessel includes a lateral wall having an outer surface around which a plurality of flexible heater elements are attached. Each heater element includes a transparent surface area, a heat conductive element extending along the transparent surface area, a temperature sensing element extending along the transparent surface area, and an electrical contact element connected to the heat conductive element and the temperature sensing element. The transparent heater element allows unobstructed view into the interior of its vessel, and reduces the time required to achieve a stabilized set point temperature in the vessel. A heater control system communicates with each heat conductive element and each temperature sensing element through a corresponding one of the electrical contact elements. The heater control system permits each vessel to be controlled independently of the other vessels.

Claims

1. A heater element comprising:

(a) first and second clear, flexible films;

(b) a temperature sensing element interposed between the first and second films and adhered to a first side of an internal adhesive;

(c) a heat conductive element interposed between the first and second films and adhered to a second side of the internal adhesive; and

(d) an electrical contact element connected to the heat conductive element and the temperature sensing element.

2. The heater element according to claim 1 wherein the temperature sensing element comprises an elongate temperature sensing portion including a plurality of horizontal and vertical sections substantially uniformly distributed over a surface area of the heater element.

3. The heater element according to claim 1 wherein the heat conductive element comprises an elongate heat conductive portion including a plurality of horizontal and vertical sections substantially uniformly distributed over a surface area of the heater element.

4. The heater element according to claim 1 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected to the heat conductive element, and at least one other of the contact plates is connected to the temperature sensing element.

5. A heater element comprising:

(a) first, second, and third clear, flexible films;

(b) a temperature sensing element interposed between the first and second films;

(c) a heat conductive element interposed between the second and third films; and

(d) an electrical contact element connected to the heat conductive element and the temperature sensing element.

6. The heater element according to claim 5 wherein the temperature sensing element comprises an elongate temperature sensing portion including a plurality of horizontal and vertical sections substantially uniformly distributed over a surface area of the heater element.

7. The heater element according to claim 5 wherein the heat conductive element comprises an elongate heat conductive portion including a plurality of horizontal and vertical sections substantially uniformly distributed over a surface area of the heater element.

8. The heater element according to claim 5 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected to the heat conductive element, and at least one other of the contact plates is connected to the temperature sensing element.

9. A vessel heating system comprising:

(a) a vessel including a lateral wall having an outer surface; and

(b) a flexible heater element attached to the outer surface of the lateral wall, the heater element including a transparent surface area, a heat conductive element extending along the transparent surface area, a temperature sensing element extending along the transparent surface area, and an electrical contact element connected to the heat conductive element and the temperature sensing element.

10.The vessel heating system according to claim 9 comprising a transparent vessel isolation chamber, wherein the vessel extends into the vessel isolation chamber, the heater element is interposed between the vessel and the vessel isolation chamber, and the vessel and vessel isolation chamber cooperatively define an annular gap adjacent to the heater element.

10. The vessel heating system according to claim 9 wherein the vessel is mounted to a vessel plate.

14. The vessel heating system according to claim 9 comprising a temperature probe extendable into an interior space of the vessel.

17. The vessel heating system according to claim 18 comprising a protective sensor attached to the heater element and communicating with the heater control circuit.

18. The vessel heating system according to claim 9 wherein the flexible heater element is attached to the outer surface of the lateral wall of the vessel by a pressure-sensitive adhesive.

21.The vessel heating system according to claim 9 wherein the flexible heater element is baked onto the outer surface of the lateral wall of the vessel.

19. The vessel heating system according to claim 9 comprising means for mounting the vessel in a consistent, repeatable position with respect to a vessel plate.

11. The vessel heating system according to claim 11 comprising a set of plunger contacts mounted to the vessel plate and connected to the electrical contact element.

12. The vessel heating system according to claim 11 comprising a transparent vessel isolation chamber, wherein the vessel extends into the vessel isolation chamber, the heater element is interposed between the vessel and the vessel isolation chamber, and the vessel and vessel isolation chamber cooperatively define an annular gap adjacent to the heater element.

13. The vessel heating system according to claim 12 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected between the heat conductive element and at least one of the plunger contacts, and at least one other of the contact plates is connected between the temperature sensing element and at least one other of the plunger contacts.

16. The vessel heating system according to claim 16 comprising a temperature probe extendable into an interior space of the vessel and communicating with the heater control circuit.

15. The vessel heating system according to claim 9 comprising a heater control circuit communicating with the heat conductive element and the temperature sensing element through the electrical contact element.

17.The vessel heating system according to claim 16 comprising a plurality of vessels and a plurality of corresponding heater elements, wherein the heater control circuit communicates with the heat conductive element of each heater element and with the temperature sensing element of each heater element.

20. A dissolution testing system comprising:

(a) a vessel plate;

(b) a plurality of vessels mounted on the vessel plate, each vessel including a lateral wall having an outer surface;

(c) a plurality of flexible heater elements, each heater element attached to the outer surface of the lateral wall of a corresponding one of the vessels, wherein each heater element includes a transparent surface area, a heat conductive element extending along the transparent surface area, a temperature sensing element extending along the transparent surface area, and an electrical contact element connected to the heat conductive element and the temperature sensing element; and

(d) a heater control system communicating with each heat conductive element and each temperature sensing element through a corresponding one of the electrical contact elements.

23. The dissolution testing system according to claim 23 comprising means for mounting each vessel respectively in a consistent, repeatable position with respect to the vessel plate.

21. The dissolution testing system according to claim 23 comprising a plurality of transparent vessel isolation chambers mounted to the vessel plate, wherein each vessel extends into a corresponding one of the vessel isolation chambers, each heater element is interposed between its corresponding vessel and vessel isolation chamber, and each corresponding vessel and vessel isolation chamber cooperatively define an annular gap adjacent to the heater element.

22. The dissolution testing system according to claim 23 comprising a plurality of temperature probes, each temperature probe extendable into a corresponding one of the vessels and communicating with the heater control system.

24. The dissolution testing system according to claim 23 comprising a set of plunger contacts supported by the vessel plate in communication with the electrical contact element.

26. A method for heating a vessel without the use of a fluid heating medium comprising the steps of:

(a) providing a flexible heater element around a circumference of a vessel, the heater element including a transparent surface area, a heat conductive element extending along the transparent surface area, a temperature sensing element extending along the transparent surface area, and an electrical contact element connected to the heat conductive element and the temperature sensing element;

(b) dispensing a substance into the vessel;

(c) extending a temperature probe into the substance;

(d) supplying electrical power to the heat conductive element to cause heat energy to transfer into the substance;

(e) supplying electrical power to the temperature sensing element;

(f) using the temperature probe to monitor the temperature of the substance as the substance is heated by the heat conductive element, and to determine when the substance has reached a predetermined set point temperature;

(g) reading a value measured by the temperature sensing element corresponding to the set point temperature; and

(h) using the value measured by the temperature sensing element to maintain the set point temperature.

29. A heater element comprising:

(a) a plurality of clear, flexible films including a first film and a second film;

(b) a temperature sensing element interposed between the first and second films and adhered to a first side of an internal adhesive, the temperature sensing element including an elongate temperature sensing portion extending over a surface area of the heater element along a first alternating, serpentine course;

(c) a heat conductive element interposed between the first and second films and adhered to a second side of the internal adhesive, the heat conductive element including an elongate heat conductive portion extending over the surface area of the heater element along a second alternating, serpentine course adjacent to the first course; and

(d) an electrical contact element connected to the heat conductive element and the temperature sensing element.

25. The dissolution testing system according to claim 27 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected between the heat conductive element and at least one of the plunger contacts, and at least one other of the contact plates is connected between the temperature sensing element and at least one other of the plunger contacts.

27. The method according to claim 29 comprising the step of extending the vessel into a vessel isolation chamber to reduce the effects of external thermal influences.

28. The method according to claim 29 comprising the steps of providing a vessel plate, mounting a contact block to the vessel plate, and connecting the electrical contact element to the contact block to ensure that the vessel is disposed in a consistent, repeatable position with respect to the vessel plate.

32. The heater element according to claim 32 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected to the heat conductive element, and at least one other of the contact plates is connected to the temperature sensing element.

30. The heater element according to claim 32 wherein the elongate temperature sensing portion includes a plurality of horizontal and vertical sections substantially uniformly distributed over the surface area of the heater element.

31. The heater element according to claim 32 wherein the elongate heat conductive portion includes a plurality of horizontal and vertical sections substantially uniformly distributed over the surface area of the heater element.

33. A heater element comprising:

(a) a plurality of clear, flexible films including a first film, a second film, and a third film;

(b) a temperature sensing element interposed between the first and second films, the temperature sensing element including an elongate temperature sensing portion extending over a surface area of the heater element along a first alternating, serpentine course;

(c) a heat conductive element interposed between the second and third films, the heat conductive element including an elongate heat conductive portion extending over the surface area of the heater element along a second alternating, serpentine course adjacent to the first course; and

(d) an electrical contact element connected to the heat conductive element and the temperature sensing element.

36. The heater element according to claim 36 wherein the electrical contact element includes a plurality of contact plates, at least one of the contact plates is connected to the heat conductive element, and at least one other of the contact plates is connected to the temperature sensing element.

34. The heater element according to claim 36 wherein the elongate temperature sensing portion includes a plurality of horizontal and vertical sections substantially uniformly distributed over the surface area of the heater element.

35. The heater element according to claim 36 wherein the elongate heat conductive portion includes a plurality of horizontal and vertical sections substantially uniformly distributed over the surface area of the heater element.