Multifunction sensor

• US 6,542,761 B1
• Filed: 08/19/1999
• Issued: 04/01/2003
• Est. Priority Date: 08/19/1998
• Status: Expired due to Term

• Current Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Inventors: Peter, Harald, Krämer, Matthias, Koerdt, Franz Wilhelm, Jahn, Paul, Metzner, Klaus, Steinbach, Bernd, Pieper, Walter
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US09/377,287
• Time in Patent Office: 1,321 Days
• Field of Search: 604/3-7, 604/403-416, 604/27-29, 600/309-311, 600/316, 600/322-327, 600/332, 600/364-366, 600/372-375, 600/377-382, 210/321--32, 210/634, 210/641-646
• US Class Current: 600/310
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/122 using evacuated interfaces to enhance contact
• CPC Class Codes: A61M 2205/123 with incorporated reservoirs
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2230/207 hematocrit

Abstract

A device for measuring parameters of medical fluids having a measurement chamber through which the fluid to be measured passes. The chamber is sealed on one side by a flexible membrane, and it also has a measurement plate that has a peripheral seal on its outer edge and is in contact with the flexible membrane. At least one sensor for measuring a parameter of the medical fluid is mounted on the measurement plate, and the measurement plate has a continuous inlet leading to the flexible membrane so that a vacuum can be established between the measurement plate and the flexible membrane.

Claims

1. A device for measuring selected parameters of a medical fluid, comprising:

a measurement chamber through which the fluid flows, sealed on at least one side by a flexible membrane;

a measurement plate having a peripheral seal on an outer edge, in contact with the flexible membrane;

at least one sensor for measuring the selected parameters of the medical fluid, disposed on the measurement plate;

a passage connecting an inlet opening between the measurement plate and the flexible membrane to a vacuum source, so that a vacuum can be established between the measurement plate and the flexible membrane;

an additional measurement plate;

at least one transmitter element mounted on a first one of the measurement plate and the additional plate; and

at least one receiver element mounted on a second one of the measurement plate and the additional measurement plate, the receiver element paired with the transmitter element.

2. The device according to claim 1, wherein one of the at least one sensor is a pressure sensor for measuring a pressure on the flexible membrane, and another of the at least one sensor is a temperature sensor for measuring a temperature on the flexible membrane.

3. The device according to claim 1, wherein a contact area of the at least one sensor is in flush contact with a bottom edge of the measurement plate.

4. The device according to claim 1, further comprising:

the additional measurement plate having a peripheral seal on an edge, disposed substantially parallel to the measurement plate;

spacers disposed between the measurement plate and the additional measurement plate, for maintaining the two plates a selected distance apart;

a second flexible membrane sealing a side of the measurement chamber facing the additional measurement plate, in contact with the additional measurement plate; and

a second passage connecting a second inlet opening between the additional measurement plate and the second flexible membrane to the vacuum source, so that a vacuum can be established between the additional measurement plate and the second flexible membrane.

5. The device according to claim 4, further comprising an ultrasonic sensor mounted on the measurement plate for an ultrasound propagation time measurement.

6. The device according to claim 4, wherein the spacers engage centering holes provided in the measurement plate and additional measurement plate.

7. The device according to claim 1, wherein the transmitter element is an ultrasonic transmitter and the receiver element is an ultrasonic receiver.

8. The device according to claim 1, wherein the transmitter element is a light source, and the receiver element is a light receiver.

9. The device according to claim 1, wherein the peripheral seal is formed by a rubber ring inserted into a groove formed on the measurement plate, and projects beyond the outer edge of the measurement plate.

10. The device according to claim 1, wherein the flexible membrane is a thin plastic film.

11. The device according to claim 1, wherein the measurement chamber is a plastic chamber with rigid walls.

12. The decive according to claims 1, wherein the flexible membrane and the measurement chamber are integrated into a disposable part.

13. The device according to claim 1, wherein the measurement plate is a metal disk on which the at least one sensor is mounted.

14. The device according to claim 13, further comprising Peltier elements associated with the metal disk to keep the metal disk at a constant temperature.

15. The device according claim 1, further comprising a computer unit connected at the at least one sensor for processing signals from the at least one sensor.

16. A method for measuring selected parameters of a medical fluid, comprising:

flowing the medical fluid through a measurement chamber having at least one side formed by a flexible membrane;

forming a vacuum between the flexible membrane and at least one measuring plate, the at least one measuring plate being adjacent to the at least one side formed by the flexible membrane;

measuring the selected parameters with sensors mounted on the at least one measuring plate, in contact with the flexible membrane;

providing an additional measurement plate;

providing at least one transmitter element mounted on a first one of the measurement plate and the additional measurement plate; and

providing at least one receiver element mounted on a second one of the measurement plate and the additional measurement plate, the receiver element paired with the transmitter element. plates being maintained a selected distance apart by spacers.

17. The method according to claim 16, further comprising the steps of performing time propagation measurements using sensors mounted on two measurement plates disposed on opposite sides of the measurement chamber, the two measurement plates being maintained a selected distance apart by spacers.

18. The method according to claim 16, further comprising the step of maintaining the at least one measuring plate at a selected temperature.