Pyroelectric calorimeter

• US 5,030,012 A
• Filed: 04/30/1990
• Issued: 07/09/1991
• Est. Priority Date: 02/02/1989
• Status: Expired due to Term

• Current Assignee: United States Department Of Health And Human Services (Government of the United States of America)
• Original Assignee: United States Department Of Health And Human Services (Government of the United States of America)
• Inventors: Yoshikami, Shuko, Hagins, William A.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): GUTIERREZ, DIEGO F
• Application Number:
  US07/507,544
• Time in Patent Office: 435 Days
• Field of Search: 374/29, 374/30, 374/31, 374/32, 374/33, 374/34, 374/44
• US Class Current: 374/31
• CPC Class Codes: G01K 17/00 Measuring quantity of heat measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N
• CPC Class Codes: G01N 25/482 concerning the temperature responsive elements measuring temperature or quantity of heat, thermally-sensitive elements G01K; thermoelectric devices H10N10/00, H10N15/00

Abstract

A pyroelectric calorimeter including a detector having a support member with a tapered through-hole therein, a first polyester film positioned on said support member, across said through-hole, an aluminum foil member located on an opposite side of said polyester film from said support member, a pyroelectric film located on an opposite side of said aluminum foil member from said first polyester film, at least one additional polyester film located on an opposite side of said pyroelectric film from said aluminum foil member, two pyroelectrical leads connected to opposite sides of said pyroelectric film, a support for the detector and electrical circuitry for receiving a signal produced from the detector and for generating an output signal therefrom.

Claims

1. A pyroelectric calorimeter which comprises, in combination, a pyroelectric detector including a support member having a tapered through-hole therein, a first polyester film positioned on said support member, across said through-hole, an aluminum foil member located on an opposite side of said polyester film from said support member, a pyroelectric film located on an opposite side of said aluminum foil member from said first polyester film, at least one additional polyester film located on an opposite side of said pyroelectric film from said aluminum foil member, and two pyroelectric leads connected to opposite sides of said pyroelectric film, means for supporting said detector and electrical circuitry means for receiving a signal produced from said detector and generating an output signal therefrom.

2. The pyroelectric calorimeter of claim 1 wherein said means for supporting said detector comprises a housing means for containing at least a portion of said electrical circuitry means and means for adjusting the tension on the detector.

3. The pyroelectric calorimeter of claim 2 wherein said means for adjusting the tension comprises first and second housing elements which are movable with respect to one another.

4. The pyroelectric calorimeter of claim 3, wherein said first and second housing elements are threadedly connected to one another.

5. The pyroelectric calorimeter of claim 1 wherein said means for supporting said detector comprises a sample support means.

6. The pyroelectric calorimeter of claim 5 further including means to irradiate samples located on said sample support means.

7. The pyroelectric calorimeter of claim 6 wherein said means to irradiate the samples is located on a cover member that can be placed on a top portion of said housing means.

8. The pyroelectric calorimeter of claim 1 wherein said electrical circuitry means comprises a preamplifier circuit including first and second operational amplifiers that are connected to one each of said two electrical leads from said detector, said first and second operational amplifiers each connected to individual feedback networks which networks include polystyrene capacitors having leakage resistances greater than about 10¹³ Ω

.

9. The pyroelectric calorimeter of claim 8 wherein said electrical circuitry means further comprises a reset circuit that includes means to generate reset signals when said polystyrene capacitors reach a preset voltage.

10. The pyroelectric calorimeter of claim 8 wherein said electrical circuitry means further comprises an amplifier circuit which receives signals from said preamplifier circuit and generates a first direct output signal that is proportional to temperature changes in the pyroelectric film and a second direct output signal that is responsive to capacitatively coupled potential changes between a reference junction and a sample on the polyester film.

11. The pyroelectric calorimeter of claim 10 wherein said electrical circuitry means further comprises a capacitor circuit that receives said first and second direct output signal and generates a reset signal.