Non-toxic liquid column sphygmomanometer

• US 7,717,856 B2
• Filed: 05/02/2005
• Issued: 05/18/2010
• Est. Priority Date: 05/02/2005
• Status: Expired due to Fees

• Current Assignee: QDevice Medical Inc.
• Original Assignee: QDevice Medical Inc.
• Inventors: Liu, Jian, Chen, Yunquan
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): JANG, CHRISTIAN YONGKYUN
• Application Number:
  US11/118,427
• Publication Number:
  US 20060247541A1
• Time in Patent Office: 1,842 Days
• Field of Search: 600/403, 600/487, 600/497, 600/561, 600/587
• US Class Current: 600/497
• CPC Class Codes: A61B 5/023 the pressure transducers comprising a liquid column
• CPC Class Codes: A61B 5/0235 Valves specially adapted therefor

Abstract

A sphygmomanometer having an elongated tube, an air chamber coupled to a first end of the tube, and a liquid chamber coupled to a second end of the tube. The liquid chamber is partially filled with fluid and is couplable to a source of external pressure. An offset region located proximate the second end of the tube has a significantly reduced cross-sectional area so as to reduce the effect of fluid level changes on pressure measurement accuracy. At least one ventilation valve is coupled to the elongated tube and the air chamber and is operative to vent the elongated tube and the air chamber to atmosphere.

Claims

1. A sphygmomanometer, comprising:

(a) an elongated tube;

(b) an air chamber coupled to a first end of said tube;

(c) a liquid chamber coupled to a second end of said tube, said liquid chamber partially filled with fluid and couplable to a source of external pressure;

(d) an offset section proximate the second end of said elongated tube having a liquid offset channel of a significantly reduced cross-sectional area so as to reduce the effect of fluid level changes on pressure measurement accuracy; and

(e) at least one ventilation valve coupled to one of said elongated tube and said air chamber operative to vent said elongated tube and said air chamber to atmosphere, including a pressure switch coupled to an external pressure source and a barometric pressure and pressure error monitor coupled to said pressure switch and wherein said pressure switch on closing, closes an electrical circuit coupled to said barometric pressure and pressure error monitor causing said barometric pressure and pressure error monitor to become activated.

2. A sphygmomanometer according to claim 1, including a vapour loss reduction air valve intermediate said liquid chamber and an external pressure source, operative to reduce vapour loss and to permit the passage of air between said external pressure source and said liquid chamber.

3. A sphygmomanometer according to claim 1, wherein a cross section of an interior surface of said elongated tube varies along its length to compensate for non-linearity in Boyle'"'"'s law so as to linearly display pressure.

4. A sphygmomanometer according to claim 1, including a pressure switch coupled to said liquid chamber and operative to switch on said barometric pressure and pressure error monitor upon being pressurized.

5. A sphygmomanometer according to claim 4, wherein said barometric pressure and pressure error monitor displays, upon being switched on, a difference between current barometric pressure and an installation barometric pressure as a percentage of an installation barometric pressure.

6. A sphygmomanometer according to claim 4, wherein said pressure switch includes a diaphragm responsive to pressure from said liquid chamber, and a plunger plate with a first side for receiving a force from said diaphragm under pressure and a second side for electrically shorting two electrical contacts upon moving in response to said force.

7. A sphygmomanometer, comprising:

(a) an elongated tube;

(b) an air chamber coupled to a first end of said tube;

(c) a liquid chamber coupled to a second end of said tube, a portion of which is filled with non-toxic liquid;

(d) one of a sliding insert, screw insert and integrated insert insertable into said air chamber and one of a barometric pressure and altitude scale on said air chamber or said one insert according to which said one insert adjusts a volume of air in said air chamber; and

(e) a ventilation valve coupled to one of said elongated tube and said air chamber operative to vent said elongated tube and said air chamber to ambient air pressure upon being open and to seal said elongated tube and said air chamber against ambient air upon being closed, including pressure switch coupled to an external pressure source and a barometric pressure and pressure error monitor coupled to said pressure switch, wherein said pressure switch on closing, closes an electrical circuit coupled to said barometric pressure and pressure error monitor causing said barometric pressure and pressure error monitor to become activated.

8. A sphygmomanometer according to claim 7, including a vapour loss reduction air valve intermediate said liquid chamber and an external pressure source, operative to block vapour loss and to permit the passage of air between said external pressure source and said liquid chamber.

9. A sphygmomanometer according to claim 7, wherein a cross section of an interior surface of said elongated tube varies along its length to compensate for non-linearity in Boyle'"'"'s law so as to linearly display pressure.

10. A sphygmomanometer according to claim 7, wherein said barometric pressure and pressure error monitor displays, upon being switched on, a difference between a current barometric pressure and an installation barometric pressure as a percentage of an installation barometric pressure.

11. A sphygmomanometer according to claim 10, wherein said pressure switch includes a diaphragm responsive to pressure from said liquid chamber, and a plunger plate with a first side for receiving a force from said diaphragm under pressure and a second side for electrically shorting two electrical contacts upon moving in response to said force.

12. A sphygmomanometer according to claim 10, including a barometric pressure and pressure error monitor and wherein said pressure switch on closing, closes an electrical circuit coupled to said barometric pressure and pressure error monitor.

13. A sphygmomanometer, comprising:

(a) an elongated tube;

(b) an air chamber coupled to a first end of said elongated tube;

(c) a liquid chamber coupled to a second end of said elongated tube, a portion of which is filled with liquid;

(d) an automatic ventilation valve coupled to said elongated tube, normally open to atmosphere and responsive to an increase in pressure of an external pressure source to close and, in response to a drop in pressure back to atmospheric pressure of said air chamber, to re-open, wherein said liquid is non-toxic, including a pressure switch and a barometric pressure and pressure error monitor coupled to said pressure switch wherein said pressure switch closes in response to an increasing source pressure and closes an electrical circuit coupled to said barometric pressure and pressure error monitor causing the latter to become activated.

14. A sphygmomanometer according to claim 13, wherein said barometric pressure and pressure error monitor displays, upon being switched on, a difference between a current barometric pressure and an installation barometric pressure as a percentage of an installation barometric pressure.

15. A sphygmomanometer, comprising:

(a) an elongated tube having a fluid passageway of varying cross sectional area along the length of the fluid passageway;

(b) an air chamber coupled to a first end of said tube;

(c) a liquid chamber coupled to a second end of said tube and couplable to a source of external pressure;

(d) an insert insertable into said air chamber for adjusting a volume of air in said air chamber; and

(e) a ventilation valve counted to one of said elongated tube and said air chamber operative to vent said elongated tube and said air chamber to atmosphere, including pressure switch coupled to an external pressure source and a barometric pressure and pressure error monitor coupled to said pressure switch, wherein said pressure switch on closing, closes an electrical circuit coupled to said barometric pressure and pressure error monitor causing said barometric pressure and pressure error monitor to become activated.

16. A sphygmomanometer, comprising:

(a) an elongated tube having a fluid passageway of varying cross sectional area along the length of the fluid passageway;

(b) an air chamber coupled to a first end of said tube;

(c) a liquid chamber coupled to a second end of said tube and couplable to a source of external pressure;

(d) an insert insertable into said air chamber for adjusting a volume of air in said air chamber; and

(e) a ventilation valve coupled to one of said elongated tube and said air chamber operative to vent said elongated tube and said air chamber to atmosphere, including a vapour loss reduction air valve intermediate said liquid chamber and an external pressure source, operative to block vapour loss and to permit the passage of air between said external pressure source and said liquid chamber.