WO1992019304A1 - A sump for liquid anaesthetic agent - Google Patents

A sump for liquid anaesthetic agent Download PDF

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Publication number
WO1992019304A1
WO1992019304A1 PCT/GB1992/000753 GB9200753W WO9219304A1 WO 1992019304 A1 WO1992019304 A1 WO 1992019304A1 GB 9200753 W GB9200753 W GB 9200753W WO 9219304 A1 WO9219304 A1 WO 9219304A1
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WO
WIPO (PCT)
Prior art keywords
sump
liquid
anaesthetic
valve
vapour
Prior art date
Application number
PCT/GB1992/000753
Other languages
French (fr)
Inventor
David Charles Sampson
Ian Mason
Original Assignee
The Boc Group Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Boc Group Plc filed Critical The Boc Group Plc
Publication of WO1992019304A1 publication Critical patent/WO1992019304A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/10—Preparation of respiratory gases or vapours
    • A61M16/14—Preparation of respiratory gases or vapours by mixing different fluids, one of them being in a liquid phase
    • A61M16/18—Vaporising devices for anaesthetic preparations
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
    • A61M16/10—Preparation of respiratory gases or vapours
    • A61M16/14—Preparation of respiratory gases or vapours by mixing different fluids, one of them being in a liquid phase
    • A61M16/18—Vaporising devices for anaesthetic preparations
    • A61M16/183—Filling systems

Definitions

  • the present invention relates to a sump for a liquid anaesthetic agent, for use in an anaesthetic vaporiser, and to an anaesthetic vaporiser which includes such a sump.
  • An anaesthetic agent is generally commonly supplied to a patient by means of an anaesthetic vaporiser, in which the agent is supplied from a sump, for example by the application of heat to cause the agent to boil, or by means of a carrier gas which is passed through the sump, for supply to the patient's breathing circuit. It is important that the agent which leaves the sump for supply to the patient is in the vapour phase for the vaporiser to operate efficiently, and in order for the amount of the agent supplied to the patient's breathing circuit to be controlled accurately.
  • the tendency for liquid anaesthetic agent to be supplied from the sump can be relatively high when the level of the liquid agent in the sump is high, approaching the level of the outlet from the sump.
  • the tendency can also be increased when a quantity of the liquid entrapped within a member in the sump is exposed to a localised source of heat, the member providing the outlet from the sump for agent which is vaporised within it.
  • a sump which is provided with such a heating arrangement is disclosed in -International patent application no. GB91/01591; subject matter disclosed in that document is incorporated in this specification by this reference to the document.
  • the present invention addresses the problem of liquid anaesthetic agent passing out of the sump of an anaesthetic vaporiser with anaesthetic vapour.
  • the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an outlet conduit from the sump body for anaesthetic agent vapour, a chamber located above the sump body through which vapour leaving the body through the outlet conduit is passed, and a liquid return conduit through which liquid anaesthetic deposited in the chamber can return to the sump body.
  • the chamber will preferably be positioned at a height sufficiently above the sump body that it is above the maximum level of liquid anaesthetic agent in a container such as a bottle from which the agent is supplied to the body. This can be established with reference to the standard sizes and shapes of containers which are used for supplying these materials.
  • the chamber can therefore act as an overflow reservoir for liquid which leaves the sump body through the outlet conduit, whether as a result of too much liquid being supplied to the sump body, or as a result of liquid being carried out of the body with anaesthetic vapour, such liquid being returned to the sump body by means of the return conduit.
  • the chamber may include elements within it for enhancing collection of liquid within the chamber.
  • the elements will generally provide an increased surface area and a tortuous pathway through which the anaesthetic vapour being carried with it must pass, so that liquid anaesthetic associated with the vapour and incident on the elements is retained in the chamber rather than passing further through the outlet conduit with the vapour.
  • the elements may be provided in the form of, for example, baffles or spherical beads.
  • the liquid return conduit is preferably provided as a separate conduit from the conduit in which anaesthetic vapour and any associated liquid anaesthetic enter the chamber, although it can be preferred for some applications for the liquid anaesthetic to be returned to the sump body through the same conduit as that through which is was carried into the chamber.
  • the chamber will have a low aspect ratio so that, for example, the value of the ratio of the square of its height to its cross-sectional area is less than about 2.0, preferably less than about 1.5, more preferably less than about 1.0.
  • This has the advantage that the depth of liquid within it is relatively insensitive to the quantity of the liquid.
  • the ability of the sump of the invention to reduce the extent to which liquid is carried out of the sump with anaesthetic vapour finds particular application when the sump incorporates a heating arrangement for converting a portion only of the liquid anaesthetic within the sump into vapour, which comprises a heater and a member of which at least a portion extends into the sump to entrap the portion of the liquid to be vaporised immediately adjacent to the heater, the member including an outlet for the passage through it of anaesthetic vapour, into the outlet conduit.
  • a vaporiser which includes such a heating arrangement is disclosed in the international patent application referred to above.
  • the sump may include a device for detecting an increase in the level of liquid in the sump body above a pre-determined level, and a valve by which flow of vapour through the outlet conduit can be controlled when that pre-determined level is exceeded.
  • the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an outlet conduit from the sump body for anaesthetic agent vapour, a device for detecting an increase in the level of liquid in the sump body above a predetermined level, and a valve by which flow of the vapour through the outlet conduit can be controlled when that predetermined level is exceeded.
  • the level detecting device may operate, for example, mechanically, optically, magnetically or electrically.
  • a particularly preferred device comprises a float which moves with the level of the liquid in the sump body, and which closes the valve to prevent further flow of fluid through the outlet conduit when the predetermined level is exceeded.
  • the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an inlet for supply of the liquid anaesthetic agent to the sump body, an outlet conduit for anaesthetic vapour from the sump body, a first valve for controlling the flow of anaesthetic vapour in the outlet conduit, and a flow control device associated with the inlet for preventing supply of liquid to the sump body when the said first valve is open.
  • the sump of this aspect of the invention has the advantage that, as a result of being able to close the outlet from the sump to flow of fluid, the maximum level of the liquid which can be supplied to the sump is restricted to a pre-determined level: additional liquid cannot be supplied to the sump since it is not possible for displaced gas to leave the sump.
  • the first valve and the flow control device are functionally connected so that supply of liquid to the sump body is possible only when the valve is closed.
  • the first valve may operate in response to an electrical signal, and the flow control device is able to generate an electrical signal to operate the valve.
  • the valve may be a solenoid valve, which is closed by an electrical signal which is generated by the flow control device when liquid is to be supplied to the sump through the inlet.
  • the flow control device may comprise a sensor for the presence of a container from which liquid is supplied to the sump.
  • the sensor may be an electrical switch, which is arranged to be operated by a container such as a bottle from which liquid is supplied to the sump, or it might be an optical or magnetic sensor which can detect the presence of the liquid container.
  • the flow control device may comprise a second valve by which flow of liquid into the sump can be prevented.
  • the second valve is functionally connected, for example mechanically connected, to the first valve so that the second valve can be opened only when the first valve is closed.
  • the second valve by which flow of liquid of liquid into the sump may be associated with an inlet conduit for connection to a supply container, and through which liquid can enter the sump body, the conduit being moveable to operate the valve between a first position in which the conduit is directed downwardly from the sump and the valve is closed, and a second position in which the conduit is directed upwardly from the sump and the valve is closed.
  • the sump of the invention may include a device for detecting an increase in the level of liquid in the sump above a predetermined level, and a valve for preventing supply of liquid to the sump body when that predetermined level is exceeded.
  • the level detecting device may operate, for example, mechanically, optically, magnetically or electrically.
  • a particularly preferred device comprises a float which moves with the level of the liquid in the sump body, and which closes the valve when the predetermined level is exceeded.
  • a sump may be provided with an inlet valve with an associated level detector, and with a chamber with an associated liquid return conduit.
  • Figure 1 is a schematic representation of a first embodiment of sump
  • Figure 2 is a schematic representation of a second embodiment of sump
  • Figure 3 is a schematic representation of a third embodiment of sump.
  • Figure 4 is a schematic representation of a fourth embodiment of sump.
  • Figure 1 shows a sump which comprises a sump body 2 for a liquid anaesthetic agent 4.
  • a heating element 6 provides a source of heat for the liquid agent contained within the sump body.
  • Anaesthetic agent is supplied to the sump body through an inlet conduit 8.
  • the inlet conduit 8 has associated with it a valve 9 which is operated by movement of a container for the liquid anaesthetic from a first position in which the container is directed downwardly from the sump and the valve is closed, and a second position in which the container is directed upwardly from the sump and the valve is closed.
  • Anaesthetic vapour leaves the sump body through an outlet conduit 10.
  • a chamber 12 is located above the sump body, vapour leaving the body through the outlet passing through the chamber.
  • a liquid return conduit 14 connects the chamber 12 and the sump body 2.
  • liquid anaesthetic agent is supplied to the sump body 2 through the inlet 8.
  • a valve 16 is provided on the inlet conduit, and is operated by means of a float 18. The float moves as the level of liquid anaesthetic within the sump body rises, and causes the valve 16 to close when the liquid reaches a predetermined level. In this way, the level of liquid anaesthetic is prevented from rising above that predetermined level.
  • the liquid anaesthetic 4 within the sump body 2 is heated by means of the heating element 6 to cause it to boil, so that anaesthetic vapour passes out of the sump body 2 through the outlet conduit 10. Droplets of liquid anaesthetic tend to pass out of the sump body 2 with the vapour.
  • the tortuous path provided through the chamber 12 in the outlet conduit 10 causes liquid anaesthetic to be retained in the chamber rather than to pass out of the chamber with anaesthetic vapour. Liquid which is retained in the chamber can flow back from the chamber into the sump body through the liquid return conduit 14.
  • the chamber 12 with its associated liquid return conduit 14 reduces the likelihood of liquid anaesthetic being carried to the patient's breathing circuit with anaesthetic vapour.
  • Figure 2 shows a sump having an outlet conduit 10 through which anaesthetic vapour is discharged.
  • the sump includes an outlet control unit 20, which includes an outlet valve 22, for closing the outlet conduit 10 to flow of fluid.
  • the outlet control unit 20 further includes a control dial 24, for controlling the amount of vapour flowing through the outlet conduit.
  • the dial 24 and the valve 22 are functionally connected so that, when the dial is set to zero flow, the valve 22 is closed.
  • a mechanical link 26 between the inlet 8 for liquid anaesthetic and the valve 22 ensures that the inlet conduit can only be opened when the dial 24 is set to zero, and the valve 22 is therefore closed.
  • liquid supplied to the sump body 2 through the inlet conduit 8 is prevented from rising above the level of the inlet conduit, due to the absence of another pathway for flow of displaced gas.
  • Figure 3 shows a sump which includes a flow control device 30 associated with the inlet 8, and an outlet valve 32 by which flow of anaesthetic vapour along the outlet conduit 10 can be prevented.
  • the outlet valve is an electrically operated solenoid valve.
  • the flow control device 30 takes the form of an electrical switch, which is operated by movement of a container, from which liquid anaesthetic is supplied to the sump body 2. A signal generated by the switch is transmitted to the outlet vial 32, so as operate that valve, to close it when a container is offered to the inlet 8, to supply liquid anaesthetic to the sump body 2.
  • Figure 4 shows a sump which includes an electrically operated solenoid outlet valve 42, and a float 44 for detecting an increase in the level of liquid in the sump above a predetermined level.
  • the float rises with the surface of the liquid.
  • a signal is generated which is transmitted to the outlet valve 42, to close that valve to flow of anaesthetic vapour along the outlet conduit 10.

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  • Health & Medical Sciences (AREA)
  • Anesthesiology (AREA)
  • Emergency Medicine (AREA)
  • Pulmonology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Abstract

Sumps for liquid anaesthetic agent for use in anaesthetic vaporisers are provided with features to minimise carry over of liquid anaesthetic agent from the sump into a patient's breathing circuit. A chamber (12) may be provided, located above the sump body (2) through which vapour leaving the body through the outlet conduit(10), and liquid agent associated with the vapour, are passed and in which the liquid agent is deposited, with a liquid return conduit (14) through which liquid anaesthetic agent deposited in the chamber can return to the sump body. A sump may be provided with a device (18) for detecting an increase in the level of liquid in the sump body above a predetermined level, and a valve by which flow of vapour through the outlet conduit from the sump body can be controlled when that predetermined level is exceeded.

Description

A SUMP FOR LIQUID ANAESTHETIC AGENT
The present invention relates to a sump for a liquid anaesthetic agent, for use in an anaesthetic vaporiser, and to an anaesthetic vaporiser which includes such a sump.
An anaesthetic agent is generally commonly supplied to a patient by means of an anaesthetic vaporiser, in which the agent is supplied from a sump, for example by the application of heat to cause the agent to boil, or by means of a carrier gas which is passed through the sump, for supply to the patient's breathing circuit. It is important that the agent which leaves the sump for supply to the patient is in the vapour phase for the vaporiser to operate efficiently, and in order for the amount of the agent supplied to the patient's breathing circuit to be controlled accurately.
The tendency for liquid anaesthetic agent to be supplied from the sump can be relatively high when the level of the liquid agent in the sump is high, approaching the level of the outlet from the sump. The tendency can also be increased when a quantity of the liquid entrapped within a member in the sump is exposed to a localised source of heat, the member providing the outlet from the sump for agent which is vaporised within it. A sump which is provided with such a heating arrangement is disclosed in -International patent application no. GB91/01591; subject matter disclosed in that document is incorporated in this specification by this reference to the document.
The present invention addresses the problem of liquid anaesthetic agent passing out of the sump of an anaesthetic vaporiser with anaesthetic vapour.
In one aspect, the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an outlet conduit from the sump body for anaesthetic agent vapour, a chamber located above the sump body through which vapour leaving the body through the outlet conduit is passed, and a liquid return conduit through which liquid anaesthetic deposited in the chamber can return to the sump body.
The chamber will preferably be positioned at a height sufficiently above the sump body that it is above the maximum level of liquid anaesthetic agent in a container such as a bottle from which the agent is supplied to the body. This can be established with reference to the standard sizes and shapes of containers which are used for supplying these materials. The chamber can therefore act as an overflow reservoir for liquid which leaves the sump body through the outlet conduit, whether as a result of too much liquid being supplied to the sump body, or as a result of liquid being carried out of the body with anaesthetic vapour, such liquid being returned to the sump body by means of the return conduit.
The chamber may include elements within it for enhancing collection of liquid within the chamber. The elements will generally provide an increased surface area and a tortuous pathway through which the anaesthetic vapour being carried with it must pass, so that liquid anaesthetic associated with the vapour and incident on the elements is retained in the chamber rather than passing further through the outlet conduit with the vapour. The elements may be provided in the form of, for example, baffles or spherical beads.
The liquid return conduit is preferably provided as a separate conduit from the conduit in which anaesthetic vapour and any associated liquid anaesthetic enter the chamber, although it can be preferred for some applications for the liquid anaesthetic to be returned to the sump body through the same conduit as that through which is was carried into the chamber.
Preferably, the chamber will have a low aspect ratio so that, for example, the value of the ratio of the square of its height to its cross-sectional area is less than about 2.0, preferably less than about 1.5, more preferably less than about 1.0. This has the advantage that the depth of liquid within it is relatively insensitive to the quantity of the liquid. However, for some applications, it might be preferred for the chamber to have a high aspect ratio; for example, the chamber might be formed as a broadened portion of the outlet conduit.
The ability of the sump of the invention to reduce the extent to which liquid is carried out of the sump with anaesthetic vapour finds particular application when the sump incorporates a heating arrangement for converting a portion only of the liquid anaesthetic within the sump into vapour, which comprises a heater and a member of which at least a portion extends into the sump to entrap the portion of the liquid to be vaporised immediately adjacent to the heater, the member including an outlet for the passage through it of anaesthetic vapour, into the outlet conduit. A vaporiser which includes such a heating arrangement is disclosed in the international patent application referred to above. The use of such a heating arrangement has the advantage that the liquid anaesthetic to be vaporised can be heated to a temperature for vaporisation quickly, without having to heat all of the liquid within the sump to that temperature. A problem with such an arrangement is that the tendency for liquid anaesthetic to be carried out of the sump with vapour can be high, as a result of vigorous boiling of the liquid within the member. That problem is addressed and solved by the present invention.
The sump may include a device for detecting an increase in the level of liquid in the sump body above a pre-determined level, and a valve by which flow of vapour through the outlet conduit can be controlled when that pre-determined level is exceeded. This feature has the advantage that, as a result of being able to close the outlet from the sump to flow of fluid, the maximum level of the liquid which can be supplied to the sump is restricted to a pre-determined level: additional liquid cannot be supplied to the sump since it is not possible for displaced gas to leave the sump, or for the pressure within the sump to exceed that in the supply container.
In a further aspect, the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an outlet conduit from the sump body for anaesthetic agent vapour, a device for detecting an increase in the level of liquid in the sump body above a predetermined level, and a valve by which flow of the vapour through the outlet conduit can be controlled when that predetermined level is exceeded.
The level detecting device may operate, for example, mechanically, optically, magnetically or electrically. A particularly preferred device comprises a float which moves with the level of the liquid in the sump body, and which closes the valve to prevent further flow of fluid through the outlet conduit when the predetermined level is exceeded.
In another aspect, the invention provides a sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an inlet for supply of the liquid anaesthetic agent to the sump body, an outlet conduit for anaesthetic vapour from the sump body, a first valve for controlling the flow of anaesthetic vapour in the outlet conduit, and a flow control device associated with the inlet for preventing supply of liquid to the sump body when the said first valve is open.
The sump of this aspect of the invention has the advantage that, as a result of being able to close the outlet from the sump to flow of fluid, the maximum level of the liquid which can be supplied to the sump is restricted to a pre-determined level: additional liquid cannot be supplied to the sump since it is not possible for displaced gas to leave the sump. Preferably, the first valve and the flow control device are functionally connected so that supply of liquid to the sump body is possible only when the valve is closed.
The first valve may operate in response to an electrical signal, and the flow control device is able to generate an electrical signal to operate the valve. For example, the valve may be a solenoid valve, which is closed by an electrical signal which is generated by the flow control device when liquid is to be supplied to the sump through the inlet.
The flow control device may comprise a sensor for the presence of a container from which liquid is supplied to the sump. For example, the sensor may be an electrical switch, which is arranged to be operated by a container such as a bottle from which liquid is supplied to the sump, or it might be an optical or magnetic sensor which can detect the presence of the liquid container.
The flow control device may comprise a second valve by which flow of liquid into the sump can be prevented. Preferably, the second valve is functionally connected, for example mechanically connected, to the first valve so that the second valve can be opened only when the first valve is closed. The second valve by which flow of liquid of liquid into the sump may be associated with an inlet conduit for connection to a supply container, and through which liquid can enter the sump body, the conduit being moveable to operate the valve between a first position in which the conduit is directed downwardly from the sump and the valve is closed, and a second position in which the conduit is directed upwardly from the sump and the valve is closed. A fluid delivery of this type is disclosed in the International patent application referred to above.
The sump of the invention may include a device for detecting an increase in the level of liquid in the sump above a predetermined level, and a valve for preventing supply of liquid to the sump body when that predetermined level is exceeded. The level detecting device may operate, for example, mechanically, optically, magnetically or electrically. A particularly preferred device comprises a float which moves with the level of the liquid in the sump body, and which closes the valve when the predetermined level is exceeded.
Features of sumps, are referred to above, may be combined; for example, a sump may be provided with an inlet valve with an associated level detector, and with a chamber with an associated liquid return conduit.
Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a schematic representation of a first embodiment of sump;
Figure 2 is a schematic representation of a second embodiment of sump;
Figure 3 is a schematic representation of a third embodiment of sump; and
Figure 4 is a schematic representation of a fourth embodiment of sump.
Referring to the drawings, Figure 1 shows a sump which comprises a sump body 2 for a liquid anaesthetic agent 4. A heating element 6 provides a source of heat for the liquid agent contained within the sump body. Anaesthetic agent is supplied to the sump body through an inlet conduit 8. The inlet conduit 8 has associated with it a valve 9 which is operated by movement of a container for the liquid anaesthetic from a first position in which the container is directed downwardly from the sump and the valve is closed, and a second position in which the container is directed upwardly from the sump and the valve is closed. Anaesthetic vapour leaves the sump body through an outlet conduit 10. A chamber 12 is located above the sump body, vapour leaving the body through the outlet passing through the chamber. A liquid return conduit 14 connects the chamber 12 and the sump body 2.
In use, liquid anaesthetic agent is supplied to the sump body 2 through the inlet 8. A valve 16 is provided on the inlet conduit, and is operated by means of a float 18. The float moves as the level of liquid anaesthetic within the sump body rises, and causes the valve 16 to close when the liquid reaches a predetermined level. In this way, the level of liquid anaesthetic is prevented from rising above that predetermined level.
The liquid anaesthetic 4 within the sump body 2 is heated by means of the heating element 6 to cause it to boil, so that anaesthetic vapour passes out of the sump body 2 through the outlet conduit 10. Droplets of liquid anaesthetic tend to pass out of the sump body 2 with the vapour. The tortuous path provided through the chamber 12 in the outlet conduit 10 causes liquid anaesthetic to be retained in the chamber rather than to pass out of the chamber with anaesthetic vapour. Liquid which is retained in the chamber can flow back from the chamber into the sump body through the liquid return conduit 14. The chamber 12 with its associated liquid return conduit 14 reduces the likelihood of liquid anaesthetic being carried to the patient's breathing circuit with anaesthetic vapour.
Figure 2 shows a sump having an outlet conduit 10 through which anaesthetic vapour is discharged. The sump includes an outlet control unit 20, which includes an outlet valve 22, for closing the outlet conduit 10 to flow of fluid. The outlet control unit 20 further includes a control dial 24, for controlling the amount of vapour flowing through the outlet conduit. The dial 24 and the valve 22 are functionally connected so that, when the dial is set to zero flow, the valve 22 is closed.
A mechanical link 26 between the inlet 8 for liquid anaesthetic and the valve 22 ensures that the inlet conduit can only be opened when the dial 24 is set to zero, and the valve 22 is therefore closed. As a result, liquid supplied to the sump body 2 through the inlet conduit 8 is prevented from rising above the level of the inlet conduit, due to the absence of another pathway for flow of displaced gas. By restricting the level of liquid anaesthetic supplied to the sump body in this way, the likelihood of liquid anaesthetic passing into the outlet conduit 10 with anaesthetic vapour is reduced.
Figure 3 shows a sump which includes a flow control device 30 associated with the inlet 8, and an outlet valve 32 by which flow of anaesthetic vapour along the outlet conduit 10 can be prevented. The outlet valve is an electrically operated solenoid valve.
The flow control device 30 takes the form of an electrical switch, which is operated by movement of a container, from which liquid anaesthetic is supplied to the sump body 2. A signal generated by the switch is transmitted to the outlet vial 32, so as operate that valve, to close it when a container is offered to the inlet 8, to supply liquid anaesthetic to the sump body 2.
Figure 4 shows a sump which includes an electrically operated solenoid outlet valve 42, and a float 44 for detecting an increase in the level of liquid in the sump above a predetermined level. When liquid is supplied to the sump body 2 through the inlet conduit 8, the float rises with the surface of the liquid. When the liquid reaches the predetermined level, a signal is generated which is transmitted to the outlet valve 42, to close that valve to flow of anaesthetic vapour along the outlet conduit 10.

Claims

CLAIMS :
1. A sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an outlet conduit from the sump body for anaesthetic agent vapour, a chamber located above the sump body through which vapour leaving the body through the outlet conduit, and liquid agent associated with the vapour, are passed and in which the liquid agent is deposited, and a liquid return conduit through which liquid anaesthetic agent deposited in the chamber can return to the sump body.
2. A sump as claimed in claim 1, in which the chamber includes elements within it for enhancing collection of liquid within the chamber.
3. A sump as claimed in claim 2, in which the elements provide a tortuous pathway along which anaesthetic vapour entering the chamber from the outlet conduit passes.
4. A sump as claimed in claim 3, in which the elements are in the form of baffles or spherical beads.
5. A sump as claimed in any one of claims 1 to 4, in which the chamber has a low aspect ratio.
6. A sump as claimed in any one of claims l to 5, which includes a valve for controlling the flow of anaesthetic vapour in the outlet conduit, and a flow control device associated with the inlet for preventing supply of liquid to the sump body when the said valve is open.
7. A sump as claimed in claimed in any one of claims 1 to 6, which includes a device for detecting an increase in the level of liquid in the sump body above a pre-determined level, and a valve by which flow of vapour through the outlet conduit can be controlled when that pre-determined level is exceeded.
8. A sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an inlet for supply of the liquid anaesthetic agent to the sump body, an outlet conduit for anaesthetic vapour from the sump body, a first valve for controlling the flow of anaesthetic vapour in the outlet conduit, and a flow control device associated with the inlet for preventing supply of liquid to the sump body when the said first valve is open.
9. A sump as claimed in claim 8, in which the first valve operates in response to an electrical signal, and in which the flow control device can generate an electrical signal to operate the said valve.
10. A sump as claimed in claim 8 or claim 9, in which the flow control device comprises a sensor for the presence of a container from which liquid is supplied to the sump.
11. A sump as claimed in claim 10, in which the sensor is an electrical switch, which is arranged to be operated by a container from which liquid is supplied to the sump.
12. A sump as claimed in any one of claims 8 to 11, in which the flow control device comprises a second valve by which flow of liquid into the sump can be prevented.
13. A sump as claimed in claim 12, in which the said second valve is operatively connected to the first valve, so that the second valve can be opened only when the first valve is closed.
14. A sump for liquid anaesthetic agent for use in an anaesthetic vaporiser, which comprises a sump body for containing the liquid anaesthetic agent, an inlet for supply of the liquid anaesthetic agent to the sump body, an outlet conduit for anaesthetic vapour from the sump body, a first valve for controlling the flow of anaesthetic vapour in the outlet conduit, and a flow control device associated with the inlet for preventing supply of liquid to the sump body when the said first valve is open.
PCT/GB1992/000753 1991-04-26 1992-04-24 A sump for liquid anaesthetic agent WO1992019304A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB919109024A GB9109024D0 (en) 1991-04-26 1991-04-26 A sump for liquid anaesthetic agent
GB9109024.1 1991-04-26

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WO1992019304A1 true WO1992019304A1 (en) 1992-11-12

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2279880A (en) * 1993-06-24 1995-01-18 Draegerwerk Ag Anaesthetic vaporiser with an intermediate container
WO2009033462A1 (en) * 2007-09-10 2009-03-19 Technologie Institut Medizin (Tim) Gmbh Device for providing anesthetic gas

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049067A1 (en) * 1980-09-09 1982-04-07 The Medishield Corporation Limited Anaesthetic vaporiser
WO1992004930A1 (en) * 1990-09-25 1992-04-02 The Boc Group Plc Sump for an anaesthetic vaporiser

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049067A1 (en) * 1980-09-09 1982-04-07 The Medishield Corporation Limited Anaesthetic vaporiser
WO1992004930A1 (en) * 1990-09-25 1992-04-02 The Boc Group Plc Sump for an anaesthetic vaporiser

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2279880A (en) * 1993-06-24 1995-01-18 Draegerwerk Ag Anaesthetic vaporiser with an intermediate container
GB2279880B (en) * 1993-06-24 1997-05-28 Draegerwerk Ag Anaesthetic vaporiser with an intermediate container
WO2009033462A1 (en) * 2007-09-10 2009-03-19 Technologie Institut Medizin (Tim) Gmbh Device for providing anesthetic gas

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