GB2126102A

GB2126102A - Humidifier

Info

Publication number: GB2126102A
Application number: GB08322609A
Authority: GB
Inventors: Orlando D Cambio
Original assignee: Kendall Co
Current assignee: Kendall Co
Priority date: 1982-08-23
Filing date: 1983-08-23
Publication date: 1984-03-21
Also published as: CA1202862A; FR2531867A1; ES8501631A1; MX159625A; SE8304555D0; SE454950B; ZA835856B; DE3329926C2; NL185652B; DE3329926A1; BR8304497A; GB8322609D0; GB2126102B; AU1831083A; AU552137B2; JPS6345832B2; DK165486B; DK386283D0; JPS5985669A; NL8302894A

Abstract

A humidifier for a patient ventilator comprises a humidifier cartridge 30 and a reservoir of sterile water 15. Air to be humidified enters the cartridge by a tube 16 and leaves at a delivery port 21. Water is supplied to the cartridge from the reservoir by a means of a tube 26 and a non-return valve 29. A level sensing tube 31 is located within the cartridge and contains water to the same level as in the reservoir. Air and water can pass to the reservoir through a tube 27, again via a non-return valve 28. The water level in the cartridge can, by this arrangement be kept constant and the reservoir is not subjected to expansion and contraction during inspiration and expiration. <IMAGE>

Description

SPECIFICATION Humidifier The present invention relates to a modification of an inhalation therapy device for use with a patient ventilator.

U.S. Patent 3,771,721 issued November 13.

1973, relates to inhalation therapy in the medical art of treating with oxygen or a mixture of oxygen and air having a high moisture content. Several classes of devices including atomizers and humidifiers are adapted for such treatment. With respect to atomizers and nebulizers as they are frequently called, a heretofore known system for inhalation therapy comprises a container for pure water which has means enabling operation of the container in one of several modes.

U.S. Patent 4,110,419 issued August, 29, 1978, and U.S. Patent 4,172,105, issued October, 23, 1 979, relate to a cartridge type humidifier apparatus that includes a separate heater module with a cylindrical opening for replaceably receiving therein disposable cylindrical humidifier cartridge modules. The cartridge modules each have a tubular metal main body adapted for a sliding fit within a complementary tubular walled heater. The metal tubular body has a rigid plastics top and bottom end portions with a separate transverse gas delivery pipe, the cap forming a closed air space over a pool of humidifying liquid.The gas to be humidified is dispersed within a hollow chamber formed between the gas inlet pipe projecting concentrally (concentrically) into the cartridge and the radially spaced wall of the main cartridge body and absorption column. The inlet tube terminates above the water. The subject matter of the above patents are incorporated herein by reference. The instant device of the present invention is a modification of the disclosure in these patents to provide an improved cartridge humidifier.

According to a first aspect of the invention, there is provided a humidifier for a ventilation system, the humidifier comprising a cartridge through which gas to be humidified can pass and containing humidifying liquid, a liquid supply tube leading from a sealed reservoir to the cartridge via a first check valve and a second tube leading upwardly from inside the cartridge to an upper portion in the sealed reservoir via a second check valve.

The second tube may be constituted by a fluid level sensing tube within the cartridge and a tubular member extending from the fluid level sensing tube to the upper portion of the reservoir.

The fluid sensing tube can lead upwardly from a lower portion of the cartridge.

The cartridge may comprise a cap attached to a main body, the cap including an inlet for gas to be humidified and an outlet for humidified gas.

The humidifier preferably comprises liquid absortion means including an open centre generally tubular liquid-absorption column member with an inner-peripheral face constituting an evaporating surface for humidifying liquid disposed generally contiguously and coextensive with a substantial part of the cartridge and adapted and constructed to be wetted directly by humidifying liquid and in a lower end portion of the cartridge and to convey by capillary action the liquid upwardly and onto the evaporating surface.

The humidifier preferably comprises means for mounting the reservoir outside the cartridge.

In a preferred embodiment, the humidifier comprises a heater for gas to be humidified.

It will be appreciated that the first check valve may prevent fluid flow, more specifically liquid (e.g. water) flow, in the liquid supply tube from the cartridge to the reservoir. It will also be appreciated that the second check valve may prevent fluid flow more specifically gas (e.g. air) flow in the second tube from the reservoir to the cartridge.

According to a second aspect of the invention there is provided a fluid feed circuit for delivering fluid from a sealed reservoir to a humidifier, the circuit comprising a liquid supply tube leading from the reservoir to a cartridge of the humidifer, through which cartridge gas to be humidified can pass, the liquid supply tube having a first check valve and a second tube leading upwardly from inside the cartridge to an upper portion in the sealed reservoir via a second check valve.

Preferred features of the second aspect of the invention are as for the first aspect mutatis mutandis.

A waterfeed circuit in accordance with the invention for delivering water from a reservoir to a humidifying apparatus connected within a ventilation system wherein the ventilation system produces a cycling pressure within the humidifier can maintain a constant water volume within the humidifier while isolating the compliance (expansion and contraction of the reservoir is significantly reduced) of the reservoir from the system. The device may include a level sensing tube positioned in the humidification apparatus.

The top of the level sensing tube can be connected by means of an air flow conduit having a check valve positioned therein that connects to an air space in the top of the reservoir of an aseptic liquid. Water may be fed to the humidifying apparatus by means of a conduit connecting the reservoir with the cylindrical cartridge of the apparatus. A check valve can be positioned in this conduit.

Although this system can be used for adult as well as a paediatric humidification, to simplify the discussion, this apparatus will be described as a modification of U.S. Patent 4,110,419, and, more specifically, U.S. Patent 4,172,105, that provide breathable inhaled gases that are moisture laden with a large quantity of water for a paediatric use.

The elements of the device that are not mentioned above are identical with the structure shown in U.S. Patent 4,172,105.

For a better understanding of the present invention and to show how it may be put into effect, reference will now be made by way of example, to the accompanying drawings, in which:~ Figure 1 is a perspective view of the assembled humidifying apparatus according to one embodiment of the invention; Figure 2 is another perspective view of the apparatus shown in Figure 1 with a portion of the structure shown in cross section; and Figure 3 is a cross sectional view of the valve and stop elements of the structure in more detail.

Since the present application covers the modification of high volume disposable and semidisposable cartridge humidifiers with selfcontained cartridge sterilising means disclosed and claimed in U.S. Patent 4,172,105, and U.S.

Patent 4,1 10,419, only the essential portions of this modified apparatus will be discussed in detail.

Reference is made to Figures 1 and 2 wherein the modification of the humidifier and nebulizer assembly is generally indicated by the member 11. The assembly comprises a combined heater cartridge supporting means 12 with a disposable or semi-disposable cartridge module 30 as shown in Figure 2, preferably with a non-metallic top body cap 13. The details of the heater and cartridge supporting module are described in detail in U.S. Patent 4,110,419.

The combined heater and cartridge-supporting module may comprise any suitable jacket type heater such as an open end metal cylindrical sleeve provided with a suitable resistance heating element and a suitable thermostatic control of any well known type. The sleeve may be fabricated from brasstubing or the like having an exemplary diameter of 28 inches (5.4 cm) a 0.051 inch (0.13 cms) wall thickness and a length range of approximately 5-7 inches (13-18 cm) or whatever dimensions may be warranted to meet certain output conditions.A 100 watt band type heater element in conjunction with the sleeve was found to perform very well, and was connected in a conventionally known manner with a single bi-metallic thermostat which may be suitably set to 1 850F (850C) to regulate the temperature of the humidified gases passing through the apparatus.

The sleeve is encased in the illustrated openended manner within a preferably insulated housing shell of any suitable rigid material. The thermostat and related heater controls may be housed within a lateral projection on the housing.

Any suitable form of switch may be used therein to initially energise the heating element. The housing shell is further preferably provided with suitable support means by which the shell/module may be suitably suspended or otherwise supported for inhalation therapy use together with a preferred form of the cartridge to be described.

A practical form of a disposable or semidisposable type humidifier cartridge module which has performed well has a cylindrical body comprised preferably of a metallic main body sleeve member, which is provided with preferably a non-metallic top body and end cap and similar non-metallic bottom end cap or liquid contacting portion. The diameter of the assembled cartridge is such as to have a sliding fit within the heater sleeve. An exemplary form of body sleeve may be fabricated of 2 inch (15 cm) diameter aluminium tubing of appropriate length. The end caps may be fabricated of any suitable rigid type plastic material or the like such as polycarbonate material which will not be adversely effected by the heater sleeve.

The cartridge module further comprises an absorption column which in one preferred mode is of a hollow cylindrical form fabricated of an absorbant blotter-like paper material, for example, 3 mm chromatography paper. The absorption column is of a size to lay closely against the inside diameter of the cartridge body, and functions to draw humidifying liquid up into the hollow centre portion of the cartridge for evaporation therein to moisture-laden gas directed therethrough. The top body cap 13 is unitarily provided with an axially centered gas inlet tube 16 having an upwardly projecting outer end adapted to be connected with a source of air or oxygen supplemented air, and the like, to be humidified.The gas inlet tube 16 is of a length so that its inner end projects a substantial distance down into and preferably concentrically relative to the cartridge body sleeve but terminates above the level of the water which may be introduced into the bottom portion of the cartridge.

The supporting means 12 is provided with a bracket means 14 to support therewith a suitably prepared water supply thermoplastic bottle 15 with which the system hereto is designed to work as aseptically prefilled bottles known as Concha preferably the Concha 1500 (1 500 ml) marketed by Respiratory Care, Inc., of Arlington Heights, Illinois, USA. The word "Concha" is a Trade Mark.

The bottle is provided with breachable seals 24 and 25 for accommodating piercing members 32 and 53 in a manner shown in Figure 2. The cap 13 is provided with a gas delivery port 21. A flexible tube 22 is shown fragmentarily in connection with a gas delivery port 21 and is adapted to deliver the treated gas to the patient. A liquid water bottle reservoir means shown in the drawing is preferably the aforesaid Concha unit placed in upright position adjacent to the supporting means 12. The unit is a disposable sealed plastic container of aseptic water. The container comprises a principal chamber 23 which is shown in the drawing as provided with breachable seals 24 and 25 and connecting tubes 26 and 27. This invention provides a method of connecting the bottle 15 with the humidifier cartridge 30 and elements designed to control the water level in the humidifier cartridge 30.

The tube 26 is connected to the bottom of the bottle 15 through the connector 25 having the piercing member 32. The other end of the tube 25 is connected through the connector 34 to the bottom of the humidifier cartridge 30. The tube 27 is connected to the top of the bottle through the connector 24 having a piercing member 53 attached thereto. The other end of the tube 27 is connected through the connector 38 to the level sensing tube 31 positioned in the humidifier cartridge 30.

Figure 3 is a cross-sectional view of the check valves 28 and 29 in Figures 1 and 2. The valves consist of an elastomeric disc 39 that moves between positions 54 and 60. When the disc is in position 54, water can flow through the conduit 26 and air can flow through the conduit 27. When the disc is in position 60, the valve is closed and water cannot flow through the conduit 26 and air cannot flow through the conduit 27.

In operation of the system the check valves 28 and 29 control the flow of the water from the reservoir 15 through the humidifier cartridge 30 and the air from the air space 40 to the level sensing tube 31. Referring again to Figure 1, clip means 50 are positioned onto 26 and 27. The apparatus includes an on and off switch 51 and a controllable member 52.

In operation of the system when the humidifier cartridge is first connected, water will flow by gravity from the bottle 1 5 to the humidifier cartridge 30 through the connectors 25 and 34.

The water will rise in the humidifier cartridge 30 and will eventually close off the air supply to the level sensing tube 31.

The water will continue to rise in the level sensing tube 31 and create a sub-atmospheric pressure in the bottle air space 40. At equilibrium the level in the sensing tube 31 will be equal to the level in the bottle 15. The difference between the sub-atmospheric pressure in the bottle and atmospheric pressure will equal the hydrostatic pressure equivalent to the difference in levels between the water in the bottle and the water in the humidifier cartridge 30.

When used for noncycling, continuous flow applications evaporation will cause a drop in the level of water in the humidifier cartridge 30 and will expose the bottom of the level sensing tube 31 to air. Some of the water in the sensing tube will drain and be replaced by air from within the humidifier cartridge 30. This will create an imbalance so that water will flow from the bottle 22 through the connector 25 and tube 26 and the connector 24 into the humidifier cartridge 30. The cycle will repeat as the water in the humidifier cartridge is used up and a constant water level will be maintained.

During the inspiration portion of a ventilator cycle, the pressure in the humidifier cartridge 30 will increase relative to the reservoir 1 5 and if the water level in the cartridge 30 is above the control level, the water will be forced into the conduit 27 and the check valve 28 will open. If the water level in the cartridge 30 is below the control level, air will move through the conduit 27 and into the reservoir 1 5. Water forced into the conduit 26 will cause the check valve 29 to close. During the expiration portion of the cycle, the pressure in the humidifier cartridge 30 will decrease substantially relative to the resevoir 15. This will cause the check valve 28 to close and the check valve 29 to open and water to move from the reservoir 15 through the conduit 26 into the cartridge 30. The system will constantly try to reach equilibrium.

The pressure in the reservoir 15 will increase until the air supply is cut off and then will decrease until the air supply is reopened. The check valve 29 in the conduit 26 prevents water from being forced back into the bottle during inspiration and allows water to flow during expiration. The check valve 28 in the conduit 27 prevents the pressure in the reservoir 15 from being relieved during expiration but also allows the air or excess water to be forced through the conduit 27 during inspiration. Another fact is that a fairly constant water level is maintained and the compliance (expansion and contraction of the reservoir is significantly reduced).

Claims

1. A humidifier for a ventilation system, the humidifier comprising a cartridge through which gas to be humidified can pass and containing humidifying liquid, a liquid supply tube leading from a sealed reservoir to the cartridge via a first check valve and a second tube leading upwardly from inside the cartridge to an upper portion in the sealed reservoir via a second check valve.

2. A humidifier as claimed in Claim 1 wherein the second tube comprises a fluid level sensing tube within the cartridge and a tubular member extending, via the second tube's check valve, to the upper portion of the reservoir.

3. A humidifier as claimed in Claim 1 or 2, wherein the cartridge comprises a cap attached to a main body, the cap including an inlet for gas to be humidified and an outlet for humidified gas.

4. A humidifier as claimed in Claim 1, 2, or 3, comprising liquid absorption means.

5. A humidifier as claimed in Claim 4 wherein the liquid absorption means includes an open centre generally tubular liquid-absorption column member with an inner peripheral face constituting an evaporating surface for humidifying a substantial part of the cartridge and adapted and constructed to be wetted directly by humidifying liquid when in a lower end portion of the cartridge, and to convey by capillary action the liquid upwardly and onto the evaporating surface.

6. A humidifier as claimed in any one of Claims 1 to 5 comprising means for mounting the reservoir outside the cartridge.

7. A humidifier as claimed in any of Claims 1 to 6 comprising a heater for gas humidified.

8. A humidifier as claimed in any one of Claims 1 to 7 wherein the first check valve prevents fluid flow in the liquid supply to be from the cartridge to the reservoir.

9. A humidifier as claimed in any one of Claims 1 to 8 wherein the second check valve prevents fluid flow in the second tube from the reservoir to the cartridge.

10. A fluid feed circuit for delivering fluid from a sealed reservoir to a humidifier, the circuit comprising a liquid supply tube leading from the reservoir to a cartridge of the humidifier, through which cartridge gas to be humidified can pass, the liquid supply tube having a first check valve and a second tube leading upwardly from inside the cartridge to an upper portion in the sealed reservoir via a second check valve.

11. A humidifier substantially as described with reference to the accompanying drawings.

12. A fluid feed circuit substanitally as described with reference to the accompanying drawings.

13. A waterfeed circuit for delivering water from a reservoir to a humidifying apparatus wherein the ventilating system produces a cyclic pressure within the humidifier and the circuit maintains a constant water volume within the humidifier while isolating the compliance of said reservoir from said system comprising:: (a) a humidifier cartridge module means embodying a tubular cartridge main body portion with an inner peripheral wall; (b) said cartridge module means including an upper end portion with cap means attached to said main body; (c) said humidifier cartridge module means including a lower end portion terminating in a transverse wall and adapted and constructed to retain a humidifying liquid, said transverse wall having liquid inlet means adapted to be fluidly connected via conduit means with a liquid outlet means of an external liquid source;; (d) said humidifier cartridge module means further comprising liquid absorption means including an open centre generally tubular liquidabsorption column member with an innerperipheral face constituting an evaporating surface for humidifying liquid disposed generally contiguously and coextensive with a substantial part of said cartridge main body and said lower end portion adapted and constructed to be wetted directly by the humidifying liquid when liquid is in said lower end portion, and to convey by capillary action the liquid upwardly of said absorption means and onto said evaporating surface; (e) a fluid level sensing tube positioned in said humidifier cartridge module parallel to said central tubular liquid absorption column and extending from near the bottom of said humidifier cartridge module to said upper end portion cap means;; (f) said upper end portion cap means of said humidifier cartridge module means of paragraph (b) together with a portion of said main body providing an air space above the humidifying liquid level in said lower end portion of said paragraph (c) when liquid is in said lower end portion; (g) said cap means including a breathable gas inlet feed pipe for directing gas to be humidified into said module and terminating in said main body; (h) said cap means further including an outwardly projecting humidified breathable gas outlet delivery pipe in fluid communication with said air space;; (i) a disposable reservoir of aseptic liquid sealed therein, said disposable reservoir having a liquid outlet pipe, means for detachably mounting said reservoir externally of said module means, and liquid inlet means adapted to fluidly connect via conduit means with said liquid outlet means of said external reservoir of aseptic liquid with said module means wherein said conduit means comprises a first tubular member having a check valve positioned therein, one end of said tubular member connected to the liquid outlet of said reservoir, the other end of said tubular member connecting to the inlet of said module, a second tubular conduit having a check valve therein, one end of said second tubular conduit connecting said level sensing tube in said upper end portion cap means, the other end of said second tubular member connecting through said check valve to the upper portion of said reservoir of aseptic liquid.

14. A cartridge humidifying apparatus for humidifying and heating a breathable gas such as oxygen supplemented air to be inhaled by a patient undergoing inhalation therapy comprising: (a) a humidifier cartridge module means embodying a tubular cartridge main body portion with an inner peripheral wall; (b) said cartridge module means including an upper end portion with cap means attached to said main body; (c) said humidifier cartridge module means including a lower end portion terminating in a transverse wall and adapted and constructed to retain a humidifying liquid, said transverse wall having liquid inlet means adapted to be fluidly connected via conduit means with a liquid outlet means of an external liquid source;; (d) said humidifier cartridge module means further comprising liquid absorption means including an open centre generally tubular liquidabsorption column member with an innerperipheral face constituting an evaporating surface for humidifying liquid disposed generally contiguously and coextensive with a substantial part of said cartridge main body and said lower end portion adapted and constructed to be wetted directly by the humidifying liquid when liquid is is said lower end portion, and to convey by capillary action the liquid upwardly of said absorption means and onto said evaporating surface; (e) a fluid level sensing tube positioned in said humidifier cartridge module adjacent to said central tubular liquid absorption column and extending from near the bottom of said humidifier cartridge module to said upper end portion cap means; ; (f) said upper end portion cap means of said humidifier cartridge module means of paragraph (b) together with a portion of said main body providing an air space above the humidifying liquid level in said lower end portion of said paragraph (c) when liquid is in said lower end portion; (g) said cap means including a breathable gas inlet feed pipe for directing gas to be humidified into said module and terminating in said main body; (h) said cap means further including an outwardly projecting humidified breathable gas outlet delivery pipe in fluid communication with said air space, said delivery pipe adapted to be connected with an output delivery tube;; (i) a disposable reservoir of aseptic liquid sealed therein, said disposable reservoir having a liquid outlet pipe, means for detachably mounting said reservoir externally of said module means and liquid inlet means adapted to fluidly connect via conduit means with said liquid outlet means of said external reservoir of aseptic liquid with said module means wherein said conduit means comprises a first tubular member having a check valve positioned therein, one end of said tubular member connected to the liquid outlet of said reservoir, the other end of said tubular member connecting to the inlet of said module, a second tubular conduit having a check valve therein, one end of said second tubular conduit connecting said level sensing tube in said upper end portion cap means, the other end of said second tubular member connecting through said check valve to the upper portion of said reservoir of aseptic liquid.