Float-Controlled Humidifier

This invention relates to humidifiers and particularly, though not solely, for use in providing humidified gases to a patient in a hospital in need of such humidified gases, for example, in intensive care situations.

It is an object of the invention to provide an apparatus for humidifying gases comprising a gas chamber having an inlet and an outlet to enable gases to be passed through said chamber; an interconnected water compartment; a float in the gas chamber; a water inlet and a water conduit leading to the water compartment; and a water control valve having a movable member and a valve seat in the water conduit, the movable member being movable by the float so that when more than a predetermined amount of water enters the gas chamber from the water compartment, the float actuates the movable member relative to the valve seat to prevent further entry of water into said water compartment.

In a further aspect the invention consists in a conduit for fluid containing a valve constructed, arranged and operable substantially as herein described with reference to and as illustrated by the accompanying drawings.

In a still further aspect the invention consists in a conduit for fluid and containing a valve, the valve comprising a valve seat surrounding a valve orifice leading into the conduit and a flexible wall to the conduit, part of the flexible wall also acting as a movable member of the valve, and valve actuating means operable to apply pressure to the part of the flexible wall which actuating means on the movable member causing closing of the valve and release of pressure permitting flow of fluid through the conduit.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

The invention will now be described in detail with reference to the accompanying drawings wherein:

FIG. 1 is a cross-sectional view, taken along line I--I of FIG. 2, of a humidifier constructed according to the invention;

FIG. 2 is a cross-sectional view taken along line II--II of FIG. 1;

FIG. 3 is a fragmented cross-sectional view showing a hinging means between a wall mounting means and an arm carrying a float;

FIG. 4 is an enlarged elevational view of a connection means and valve forming part of the invention;

FIG. 5 is a cross-sectional view taken along line V--V of FIG. 4;

FIGS. 6, 7 and 8 are respectively a vertical cross-sectional, a horizontal cross-sectional and an elevational view of a flexible valve member forming part of the valve of FIGS. 4 and 5;

FIG. 9 is an enlarged cross-sectional view of the valve and associated parts of the construction shown in FIG. 1;

FIG. 10 is a cross-sectional view taken along line X--X of FIG. 9 with certain parts omitted; and

FIG. 11 is a view similar to FIG. 10 but showing a different embodiment using a double valve arrangement.

Referring to the drawings, a humidifier 1 is provided with a gas chamber 2 and a water compartment 3, the gas chamber 2 being interconnected with the water compartment 3 by being disposed above the water compartment 3 and a microporous wall 4 between and common to the chamber 2 and the water compartment 3. The microporous wall is made of a microporous material having the property of being permeable to water vapor but substantially impermeable to liquid water and is made for example of expanded PTFE (polytetrafluoroethylene) and the material is preferably flexible, inert and hydrophobic. Such a material is sheet material manufactured under the trade name Gortex and is available from W. L. Gore and Associates Inc., Delaware, U.S.A.

This material is thin and to resist the pressures operating due to water being fed to the water compartment 3 from a bag (not shown) suspended on a pole (not shown) positioned adjacent to a hospital patient using the humidifier, the microporous material is mounted on a supporting frame 5 which as may be seen from FIG. 2 is arranged in a horizontal plane with a series of crossing ribs below which the microporous material 4 is positioned. Any suitable rib pattern may be used.

The support 5 is made of a plastics material and molded during an injection molding operation, which at the same time, provides a pair of upstanding strips 10 and a water connection mount 11 molded integrally with the support 5. The water connection mount 11 has a water inlet 12. The mount 11 is mounted in the wall 13 of the gas chamber 2 by using a solvent cement or otherwise as desired. A water delivery orifice 14 is provided in the molded product surrounded by a valve seat 15 leading to a passageway in the form of a slot 16 which passes through the microporous wall support member 5 and thus leads through an outlet 17 into the water compartment 3. A flexible member 20 is molded in a separate operation for example from thin sheet synthetic rubber, e.g. T.P.R. Santoprene 271-47 in a shape as shown in FIGS. 4 to 10 and in the above molding operation to provide the support 5, the flexible member 20 is molded into the outer perimeter 21 of the water connection, the flexible member 20 thereby forming a front wall of the slot 16 and sealing the slot 16 apart from gas chamber 2. The flexible member 20 has a thickened part 22 which provides a valve member which if pressed against the valve seat 15 closes off the entry of water to the slot 16 and thus the water compartment 3.

To assist in giving a complete closing off action the part 18 (FIG. 5) of the water connection close to the valve seat 15 is, if desired, made of a comparatively thick section, shrinkage of which causes an annular protruding lip to be formed about the orifice 14 to form the valve seat 15 as shown in cross section in FIG. 5.

To effect such closing off, a float 25 is provided connected to a set of arms 26, and a cross member 27 is provided with slots 28 (see FIG. 10) which in use slip over the upstanding strips 10. The strips preferably have shoulders 24 near the free ends to prevent inadvertent lifting off of the slotted arms. The slots 28 and strips 10 provide a hinge mechanism, the strips 10 bending when the float 25 moves up for example due to water being present in the gas chamber 2. The cross member 27 carries and actuating member 30 which presses against the flexible member 20 opposite the orifice 14 and thus exerts considerable pressure on the member 20 against the seat 15 due to the leverage between the float and the member 30 when water in the gas chamber 2 causes such closing.

In order to assemble the gas chamber 2, water compartment 3 and support 5 in an air and water tight manner, the gas chamber 2 has an annular flange 34 (FIG. 9), the support 5 has an annular flange 35, and the base 36 of the water compartment 3 has an extended flange 37 a part 38 of which is rolled over flanges 34 and 35 and a gasket 39 to provide the necessary water and air tight parts.

In use, the humidifier is connected between a source of supply of gases which are connected to the inlet 32 and an outlet (not shown) is connected to breathing apparatus associated with a patient in, for example, an intensive care area of a hospital. A water supply is connected to the inlet 12 and such water supply preferably is provided in the well known bag which is mounted on a pole adjacent to the patient. The humidifier is mounted on a heating device of known type and when water in the compartment 3 is heated to a sufficient temperature, water vapor, but not liquid water, passes through the microporous wall 4 into the gas chamber 2 and thus humidifies the gas passing therethrough to the patient. However, under some circumstances, there may be a break or other condition under which the liquid water may pass through the microporous wall into the gas chamber so that the water level in the gas chamber exceeds a predetermined level. Any liquid water so entering will raise the float 25 causing the member 30 to press the flexible membrane 20 against the valve seat 15 thus closing off water supply into the water compartment. Thus, in a very simple yet effective manner a control valve is provided which obviates or minimizes the risk of the gas chamber becoming flooded and liquid water being passed on to the patient.

In some cases it may be desirable to omit the microporous wall 4 so that the water compartment is in effect simply a lower part of the gas chamber 2. Also, even using the microporous wall 4 it might be thought desirable to have an exit as well as an entry water control valve for the water compartment 3. In such circumstances a safety valve of the same construction as above described is desirable and one such construction is shown in FIG. 11. In that construction, one float arm 26 has a member 41 which contacts and moves a part 42 of flexible wall 49 to close against valve seat 43 leading from the water entry 12, i.e. substantially similarly to the valve arrangement above described except side by side of another float (not shown) on a further set of arms 44 and 45. The arm is extended to provide an actuating member 46 which contacts a thickened part 47 of the flexible wall 49 to in turn contact the orifice of an exit passageway 48 leading to the gas chamber thus providing a water exit valve. One of the floats or valve actuators, e.g. the float actuating the arms 44, 45 and actuating member 46 to operate the thickened part 47 is preferably set so that valve 50 at the water entry is closed before the exit valve 51 to enable an observer to see if the water flow is usually controlled by valve 50.

In such construction humidification occurs off the surface of the water compartment 3, aided if necessary by using a porous material of large surface area in the gas chamber 2 to increase the water evaporation rate.