Fluent material handling – with receiver or receiver coacting mea – Automatic control of flow cutoff or diversion – Level or overflow responsive
Reexamination Certificate
2003-09-04
2004-06-08
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Automatic control of flow cutoff or diversion
Level or overflow responsive
C128S200190
Reexamination Certificate
active
06745800
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to an arrangement for the overfill protection for a container of anesthetic liquid being transferred to a drug reservoir for an anesthetic vaporizer. More specifically, the present invention relates to an overfill protection device that prevents the overfilling of the drug reservoir of a vaporizer for use specifically with an anesthetic liquid having a low boiling point. The filling arrangement prevents the overfill of the drug reservoir due to the increased pressure within the anesthetic liquid storage container relative to the supply of anesthetic liquid contained within the drug reservoir.
During the supply of anesthesia, the gaseous anesthetic agent inhaled by the patient is formed of oxygen, nitrogen, nitrous oxide and an inhalation anesthetic agent. Inhalation anesthetics are typically in liquid form at administration temperatures, and an anesthetic vaporizer is needed to gasify the liquid. Anesthetic vaporizers have a drug reservoir for storing the supply of the agent to be vaporized. The vaporized anesthetic is administered for the patient to inhale by means of a carrier gas flow.
Vaporizer reservoirs are provided with fill conduits and valves by way of which inhalation liquids may be added to the container or, when necessary, drained therefrom. Liquid is added to the vaporizer reservoir by either a filling device that is specifically designed for the anesthetic agent or by directly pouring the anesthetic agent into a filling hopper. It is a characteristic of the filling device that it can only be fixed to the storage container for a desired, single type of an anesthetic liquid to be transferred to the vaporizer. Such filling device is characterized and shown in U.S. Pat. No. 6,585,016, the disclosure of which is incorporated herein by reference.
The filling device, such as shown in the above-identified patent, incorporates a liquid flow conduit and a gas flow conduit. The filling of the drug reservoir for the anesthetic vaporizer is based on the exchange of volume in the vaporizer and the storage container for the anesthetic liquid. When the anesthetic liquid flows into the vaporizer, an equivalent volume of gas flows out of the vaporizer and back into the storage container. Correspondingly, when liquid flows out of the storage container, an equivalent volume of gas flows into it. Typically, the filling of the vaporizer stops if the replacement gas flow is exhausted or blocked.
It is essential for the operation of the vaporizer that the vaporizer drug reservoir is not filled over a maximum limit. If the vaporizer reservoir is overfilled, the result may be that an overly high dose of anesthetic agent is delivered, which may, in the worst case, rapidly cause death. Otherwise, depending upon the vaporizer, the vaporizer may stop vaporizing, which would cause the patient to awaken too early.
Referring to
FIGS. 1 and 2
, thereshown is a typical filling arrangement between a drug reservoir
10
for an anesthetic vaporizer and a container
12
containing a supply
14
of an anesthetic agent. As illustrated in
FIG. 1
, a filler
16
is positioned between the container
12
and the drug reservoir
10
to provide a conduit between the container
12
and the open interior
18
of the reservoir
10
. In the prior art embodiment shown in
FIGS. 1 and 2
, the filling system is closed and the anesthetic liquid
14
is not allowed to vaporize to external atmosphere. The filler
16
includes a liquid tube
20
extending from the storage container
12
to the open interior
18
of the reservoir
10
. A gas tube
22
also extends from the container
12
to the open interior
18
of the drug reservoir
10
.
As illustrated in
FIG. 1
, when the anesthetic vapor from within the open interior
18
is withdrawn through the discharge tube
24
of the vaporizer and administered to the patient, the level of the anesthetic agent
26
falls below the inlet end
28
of the gas tube
22
. Since the supply of anesthetic agent
14
contained within the storage container
12
is typically at the same pressure as the anesthetic agent
26
within the reservoir
18
, gas travels from the drug reservoir
18
through the gas tube
22
and displaces the anesthetic agent
14
from within the storage container
12
through the liquid tube
20
. This process continues until the level of the anesthetic agent
26
within the open interior
18
rises above the inlet end
28
of the gas tube
22
. When the inlet end
28
is covered, no additional gas can flow back to the storage container
12
and filling of the drug reservoir
10
is halted. As can be seen in
FIG. 2
, the inlet end
28
of the gas tube
22
is well below the inlet end
30
of the discharge tube
22
to prevent the flow of the anesthetic agent
26
directly into the discharge tube
24
.
Presently, the filler
16
includes either keyed elements or a color coding to insure that only a desired type of anesthetic agent is used with the filling arrangement. Thus, the storage container
12
can be connected only to a filling device suitable for the particular anesthetic agent being delivered.
Unlike many other anesthetic agents, Desflurane boils at room temperature. When the anesthetic liquid begins to boil, the pressure inside the storage container
12
increases. If the temperature of the anesthetic agent
14
in the storage container
12
exceeds the temperature of the anesthetic agent
26
contained within the drug reservoir, the pressure in the storage container
12
can cause the level of the anesthetic agent
26
within the reservoir
10
to continue to rise even though the inlet end
28
of the gas tube is covered and no vapor is flowing back into the supply container
12
. In the worst case, the pressure of the Desflurane contained within the storage container
12
may cause the level of the anesthetic agent within the drug reservoir
10
to flow to the dosing device, thus causing malfunction in the entire anesthesia device. Therefore, a need exists for an arrangement for preventing the overflow of an anesthetic liquid into the liquid container of an anesthetic vaporizer, particularly when the anesthetic agent has a low boiling point.
SUMMARY OF THE INVENTION
The present invention is a filling system for use between an anesthetic storage container and an anesthetic vaporizer having a drug reservoir. The filling system of the present invention is useful in transferring a liquid anesthetic agent between the anesthetic storage container and the drug reservoir.
The filling system includes a filling device that is positioned between the drug reservoir for the vaporizer and the anesthetic storage container. The filling device includes at least one filling conduit that allows the liquid anesthetic agent to pass from the anesthetic storage container to the drug reservoir. Additionally, the filling conduit allows a flow of replenishment gas to pass from the drug reservoir back into the anesthetic storage container.
The filling conduit includes a filling opening that allows the filling conduit to empty into the drug reservoir. The filling opening provides the lone passageway for both the anesthetic agent and replenishment gas to pass between the storage container and the drug reservoir.
The filling system of the present invention includes a closing valve that is operatively positioned adjacent to the flow opening and is movable between an open position and a closed position. When the closing valve is in the closed position, the closing valve prevents the flow of the anesthetic liquid from the anesthetic storage container into the drug reservoir. The closing valve is configured to move between the open and closed positions based on the level of the anesthetic agent within the drug reservoir. Thus, the closing valve controls the flow of anesthetic agent based upon the amount of anesthetic agent within the drug reservoir, rather than based upon the flow of replacement gas between the anesthetic agent in the anesthetic storage container and the drug reservoir.
The closing valve of the pr
Andrus Sceales Starke & Sawall LLP
Datex-Ohmeda Inc.
Douglas Steven O.
LandOfFree
Arrangement for preventing overfill of anesthetic liquid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arrangement for preventing overfill of anesthetic liquid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement for preventing overfill of anesthetic liquid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3314763