Multi-temperature heater for use with pressure transducers

• US 6,772,640 B1
• Filed: 10/10/2000
• Issued: 08/10/2004
• Est. Priority Date: 10/10/2000
• Status: Expired due to Term

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Poulin, James M., Lahey, Kerry S., Maxwell, J. Robert Jr., St. Paul, Gardy, Mathew, Santhi E., Quigley, Claudia J., Mindlin, Leonid
• Primary Examiner(s): Hirshfield, Andrew H.
• Assistant Examiner(s): FERGUSON SAMRETH, MARISSA LIANA
• Application Number:
  US09/685,154
• Time in Patent Office: 1,400 Days
• Field of Search: 733/19, 737/18, 737/24, 737/28, 737/08, 737/56, 732/04, 428/220, 361/283, 361/283--28, 335/131, 335/132, 588/252, 588/256, 480/220, 219/444, 219/481
• US Class Current: 73/718
• CPC Class Codes: G01L 19/04 Means for compensating for effects of changes of temperature , i.e. other than electric compensation

Abstract

A heater is disclosed for use with pressure transducers. The disclosed heater includes a first heating element and a second heating element. The first heating element is characterized by a first electrical resistance. The second heating element is characterized by a second electrical resistance. In preferred embodiments, the first electrical resistance is different than the second electrical resistance. The disclosed heater can be used to accurately heat a pressure transducer to at least four different operating temperatures by selectively (a) connecting the first heating element to the transducer temperature control circuitry, (b) connecting the second heating element to the transducer temperature control circuitry, (c) connecting the first and second heating elements in series with the transducer temperature control circuitry, or (d) connecting the first and second heating elements in parallel with the transducer temperature control circuitry.

Claims

1. A pressure transducer, including:

(A) a shell;

(B) a pressure sensor disposed in the shell;

(C) a heater attached to the shell, the heater including a first heating element and a second heating element, the first heating element being characterized by a first electrical resistance, the second heating element being characterized by a second electrical resistance;

(D) one or more electronic components for applying an electrical signal to the heater, the heater generating heat in response to the electrical signal; and

(E) a switching element for selectively connecting any of;

(1) the first and second heating elements in series with the electronic components;

(2) the first heating element in series with the electronic components;

(3) the second heating elements in series with the electronic components and (4) the first and second heating elements in parallel with the electronic components.

2. A transducer according to claim 1, wherein the first electrical resistance is equal to the second electrical resistance.

3. A transducer according to claim 1, wherein the first electrical resistance is different than the second electrical resistance.

7. A transducer according to claim 1, further including an outer housing disposed around the shell.

8. A transducer according to claim 7, wherein the heater is disposed between the outer metallic housing and the shell.

4. A pressure transducer, including:

(A) a pressure sensor;

(B) a heated shell disposed around the sensor, the heated shell including a first heating element and a second heating element, the first heating element being characterized by a first electrical resistance, the second heating element being characterized by a second electrical resistance;

(C) one or more electronic components for applying an electrical signal to the heated shell, the heated shell generating heat in response to the electrical signal; and

(D) a switching element for selectively connecting any of;

(1) the first and second heating elements in series with the electronic components;

(2) the first heating element in series with the electronic components;

(3) the second heating elements in series with the electronic components and (4) the first and second heating elements in parallel with the electronic components.

5. A transducer according to claim 4, wherein the first electrical resistance is equal to the second electrical resistance.

6. A transducer according to claim 4, wherein the first electrical resistance is different than the second electrical resistance.

9. A transducer according to claim 4, further including an outer housing disposed around the heated shell.

10. A method of heating a pressure transducer, comprising:

(A) providing a pressure transducer including a shell, a pressure sensor disposed within the shell, a heater coupled to the shell, the heater including a first resistive heating element and a second resistive heating element, the pressure transducer further including one or more electronic components for supplying power to the heater;

(B) during a first time interval, connecting the one or more electronic components to a first configuration of the first and second resistive heating elements, the first configuration providing a first electrical resistance; and

(C) during a second time interval, after the first time interval, connecting the one or more electronic components to a second configuration of the first and second resistive heating elements, the second configuration providing a second electrical resistance, the second electrical resistance being different from the first electrical resistance.

11. A method according to claim 10, at least one of the first and second configurations having the first and second resistive heating elements connected in series.

12. A method according to claim 10, at least one of the first and second configurations having the first and second resistive heating elements connected in parallel.

13. A method according to claim 10, including:

applying power from the one or more electronic components to both the first and second resistive heating elements during one of the first and second time intervals; and

applying power from the one or more electronic components to only one of the resistive heating elements during another of the first and second time intervals.

14. A method according to claim 10, further comprising sensing a pressure using a pressure-sensitive diaphragm in the pressure sensor.

15. A method according to claim 10, further comprising increasing a temperature of the shell from a first ambient temperature to a second temperature, greater than the first ambient temperature, and operating the pressure transducer with the shell substantially at the second temperature.

16. A method according to claim 10, further comprising operating the pressure transducer at a first temperature during the first time interval, and operating the pressure transducer at a second temperature during the second time interval, the second temperature being different from the first temperature.

17. A method according to claim 10, further comprising providing an outer housing disposed around the shell.

18. A method according to claim 17, disposing the heater between the shell and the outer housing.

19. A method of heating a pressure transducer, comprising:

(A) providing a pressure transducer including a shell, a pressure sensor disposed within the shell, and a heater coupled to the shell, the heater including a first resistive heating element and a second resistive heating element, the pressure transducer further including one or more electronic components for supplying power to the heater;

(B) connecting the first and second resistive heating elements to the one or more electronic components in a first electrical configuration that provides power to both the first and second resistive heating elements, the heater when in the first electrical configuration providing a first electrical resistance; and

(C) connecting the first and second resistive heating elements to the one or more electronic components in a second electrical configuration that provides power to both the first and second resistive heating elements, the heater when in the second electrical configuration providing a second electrical resistance, the second electrical resistance being different from the first electrical resistance.

20. A method according to claim 19, the first electrical configuration being a series configuration.

21. A method according to claim 19, the first electrical configuration being a parallel configuration.

22. A method according to claim 19, further comprising connecting the first and second resistive heating elements in the first electrical configuration for a first time interval.

23. A method according to claim 19, further comprising connecting the first and second resistive heating elements in the second electrical configuration for a second time interval.

24. A method according to claim 19, further comprising increasing a temperature of the shell from a first ambient temperature to a second temperature, greater than the first ambient temperature, and operating the pressure transducer with the shell substantially at the second temperature.

25. A method according to claim 19, further comprising operating the pressure transducer at a first temperature during the first time interval, and operating the pressure transducer at a second temperature during the second time interval, the second temperature being different from the first temperature.