Anesthesia vaporizer reservoir and system

1. An anesthesia vaporizer system comprising:

a vaporizer reservoir forming a sump chamber that contains liquid anesthetic agent and a fill chamber isolated from the sump chamber configured to receive liquid anesthetic agent from a refill container;

a sump piston in the sump chamber configured to maintain an unchanging force on the liquid anesthetic agent in the sump chamber;

a transfer valve configured to permit the liquid anesthetic agent to flow from the fill chamber to the sump chamber; and

an outlet port that delivers the liquid anesthetic agent from the sump chamber to a vaporizing system that vaporizes the liquid anesthetic agent for delivery to a patient.

2. The system of claim 1 , further comprising a stationary divider in the vaporizer reservoir isolating the fill chamber from the sump chamber.

3. The system of claim 1 , further comprising a fill piston in the fill chamber configured to move between a first position and a second position, wherein as the fill piston moves from the first position toward the second position the liquid anesthetic agent is drawn from the refill container into the fill chamber.

4. The system of claim 3 , wherein the system is configured such that as the fill piston moves from the second position toward the first position, the liquid anesthetic agent is forced out of the fill chamber through the transfer valve to the sump chamber.

5. The system of claim 3 , wherein the fill piston is configured to maintain a vacuum in the fill chamber during refill so as to prevent any anesthetic agent from exiting the fill chamber as the refill container is removed from a fill port on the vaporizer reservoir.

6. The system of claim 3 , further comprising a pressure sensor in the fill chamber;

wherein the sump piston is controlled such that movement of the sump piston is stopped when the pressure sensor senses a threshold pressure decrease.

7. The system of claim 1 , further comprising a tube external to the vaporizer reservoir and communicating between the fill chamber and the sump chamber, and wherein the transfer valve is connected to the tube and configured to control flow of the liquid anesthetic agent from the fill chamber to the sump chamber.

8. The system of claim 1 , further comprising a piston position sensor that senses a position of the sump piston within the sump chamber.

9. The system of claim 8 , further comprising:

a refill proximity sensor and an empty proximity sensor each configured to sense position of the sump piston in the sump chamber;

a controller configured to generate a first alert via a user interface when the sump piston is between the refill proximity sensor and the empty proximity sensor and generates a second alert when the sump piston is at or below the empty proximity sensor.

10. The system of claim 1 , further comprising a constant spring exerting the constant force on the sump piston as it moves within the sump chamber.

11. The system of claim 1 , further comprising an air bladder exerting the constant force on the sump piston as it moves within the sump chamber.

12. The system of claim 11 , further comprising a pressure sensor in the sump chamber sensing pressure on the liquid anesthetic agent from the sump piston, wherein inflation of the air bladder is controlled based on the sensed pressure.

13. The system of claim 12 , wherein the system is configured such that the liquid anesthetic agent is continuously delivered from the sump chamber to the vaporizing system while the liquid anesthetic agent is drawn from the refill container into the fill chamber, and while the liquid anesthetic agent flows from the fill chamber into the sump chamber.

14. The system of claim 1 , further comprising a fill port on the vaporizer reservoir configured to receive the refill container containing liquid anesthetic agent; a valve in the fill port configured to permit flow of the liquid anesthetic agent from an exterior of the vaporizer reservoir into the fill chamber.

15. The system of claim 1 , further comprising a controller configured to control the sump piston to maintain the unchanging force on the liquid anesthetic agent to continuously deliver the liquid anesthetic agent through the outlet port.

16. A vaporizer reservoir for an anesthesia vaporizer system, the vaporizer reservoir having a length between a first end and a second end, the vaporizer reservoir comprising:

a sump chamber that contains liquid anesthetic agent;

a fill chamber configured to receive liquid anesthetic agent from a refill container;

a sump piston in the sump chamber configured to maintain an unchanging force on the liquid anesthetic agent therein;

a transfer valve configured to permit the liquid anesthetic agent to flow out of the fill chamber to the sump chamber; and

an outlet port that delivers the liquid anesthetic agent from the sump chamber to a vaporizing system that vaporizes the liquid anesthetic agent for delivery to a patient.

17. The vaporizer reservoir of claim 16 , further comprising a stationary divider in the vaporizer reservoir isolating the fill chamber from the sump chamber.

18. The vaporizer reservoir of claim 16 , further comprising a fill piston in the fill chamber configured to move between a first position and a second position, wherein as the fill piston moves from the first position toward the second position the liquid anesthetic agent is drawn from the refill container into the fill chamber.

19. The vaporizer reservoir of claim 18 , wherein the anesthesia vaporizer system is configured such that as the fill piston moves from the second position toward the first position, the liquid anesthetic agent is forced out of the fill chamber through the transfer valve to the sump chamber.

20. The vaporizer reservoir of claim 16 , wherein the anesthesia vaporizer system is configured to maintain a vacuum in the fill chamber so as to prevent any anesthetic agent from exiting the fill chamber as the refill container is removed from the fill port.

21. The vaporizer reservoir of claim 16 , further comprising a constant spring or an air bladder exerting the constant force on the sump piston as it moves within the sump chamber.