High fidelity pressure transducer

• US 4,129,242 A
• Filed: 05/18/1977
• Issued: 12/12/1978
• Est. Priority Date: 03/22/1976
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Karrer, Henry E., Dias, J. Fleming, Tykulsky, Alexander
• Primary Examiner(s): Smith, Al Lawrence
• Assistant Examiner(s): Ramsey, K. J.
• Application Number:
  US05/797,978
• Time in Patent Office: 573 Days
• Field of Search: 228/121, 228/122, 228/123, 228/124, 228/178, 228/188, 403/272
• US Class Current: 228/121
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

The capacitive fluid pressure transducers described herein comprise quartz bodies and diaphragms having suitable electrodes deposited thereon to form both sensing and reference capacitors in appropriate configurations for high fidelity measurement of relative blood pressure, said transducers being substantially unaffected by temperature and other environment factors.

Claims

1. A method for brazing the quartz parts of a structure comprising the steps of:

disposing a segmented band of eutectic alloy on one surface of the first part;

disposing a correspondingly segmented band of eutectic alloy on one surface of the second part;

mating the bands of alloy of the first and second parts to form the structure;

applying a mating force along a line corresponding to the mated bands of alloy;

heating the structure to approximately 200°

C. for less than an hour;

gradually increasing the heat applied to the structure approximately 260°

C. for less than one additional hour; and

gradually cooling the structure to room temperature.

2. A method for brazing the parts of a quartz structure as in claim 1 wherein the segmentation of the bands of eutectic alloy comprise alternate, co-planar, transverse strips of alloy and regions having no alloy.

3. A method for brazing the parts of a quartz structure as in claim 2 wherein each one of the transverse strips of alloy are connected to an adjacent transverse strip of alloy by co-planar links of eutectic alloy to form pairs of interconnected transverse strips.

4. A method for brazing the parts of a quartz structure as in claim 1 wherein the segmentation of the bands of eutectic alloy comprise circular deposits of alloy located along the width and length of the band.

5. A brazed quartz structure comprising:

a first part having a segmented band of eutectic alloy disposed on one surface; and

a second part having a correspondingly segmented band of eutectic alloy disposed on one surface for mating with the band of alloy on one surface of the first part;

said segmented bands of alloy being fused together for effecting a substantially uniform clamping of the first part to the second part and for reducing thermal stresses in the first and second parts.

6. A brazed quartz structure as in claim 5 wherein the segmentation of the bands of eutectic alloy comprise alternate, co-planar, transverse strips of alloy and regions having no alloy.

7. A brazed quartz structure as in claim 5 wherein the segmentation of the bands of eutectic alloy comprise circular deposits of alloy located along the width and length of the band.

8. A brazed quartz structure as in claim 7 wherein each one of the transverse strips of alloy are connected to an adjacent transverse strip of alloy by co-planar links of eutectic alloy to form pairs of interconnected transverse strips.