Nebulizer-humidifier

1

NEBULIZER-HUMIDIFIER
BACKGROUND OF THE INVENTION

Most humidifiers presently on the market bubble the 5 oxygen through water to pick up moisture. This is accomplished by passing the oxygen through a porous medium or screen which is located below the surface of the water. These so-called "bubblers" are limited in the amount of mass transfer they are able to achieve and 10 will typically produce up to about 40% relative humidity (referred to body temperature) when operated at room temperature. An additional 10% may be achieved when a nebulizer is used as a humidifier. Both apparatuses depend upon the oxygen and water interfacing for 15 a length of time and in such a manner that the contact is maximized. However during operation the operating temperature decreases and efficiencies therefore decrease.

An effective approach to increasing efficiency is to 20 increase the molecular energy of the substances by heating. The addition of heat has been a standard scheme for increasing efficiency whereby the addition of small amounts of heat increase operating efficiencies to near saturation. 25

However, the nebulizer and humidifier units presently available in the art have many disadvantages and drawbacks. Many of them are quite expensive. Reusable units require special handling and sterilization.

Units with heaters have even more problems. Since 30 these heaters have been either of the immersion type or the cuff type, they heat the entire water supply, thusly requiring a warm up time before operating efficiencies are reached and using large amounts of power. As a result they are quite inefficient. Moreover, these types 35 of heating elements present a severe burn hazard. Most of them have high failure rates, require long down times for repairs and build up deposits which reduce operating efficiency quite markedly. Most units are quite bulky, taking up large inventory spaces. 40

What is desired therefore is an improved humidifier and an improved nebulizer, preferably a single unit with an interchangeable dual function. What is also desired are improved components for such a unit. An inexpensive and disposable nebulizer nozzle is needed. 45 An inexpensive and efficient heating unit which is safe to handle and which heats only the water being used and when it is to be used instead of the entire water supply is also needed. A water container which is inexpensive and disposable and which is easily storable 50 when not in use is needed. Safety features should be resident in the unit to protect the patient. Moreover the unit should be of a design which is easily and inexpensively manufactured and which is easily cleaned and repaired. 55

SUMMARY OF THE INVENTION

The subject invention involves a medical nebulizerhumidifier apparatus for use with oxygen breathing systems wherein the apparatus may be manufactured 60 with reusable and disposable components.

A housing unit may incorporate a venturi-type nebulizer nozzle. This housing may be mounted to a water containing unit which may be a plastic bag. Extending to the bottom of the bag from the area of housing 65 mount may be a separate passageway for water or oxygen. The bag is preferably shaped to include an air space above the intended water level.

Situated within the housing unit and connecting the nozzle to the bag passageway may be a heater unit. This heater unit may incorporate a channel in its surface which when the heater is resident within the housing provides a length of heated passageway at the mating surfaces by which water in transit to the nozzle is heated.

The venturi nozzle may be structured between components insertable into the housing and the housing itself whereby jet orifice and venturi chamber functional components are created at mating surfaces.

A control mechanism may reside along with the nozzle structure to divert the oxygen flow for converting the apparatus function from nebulization to humidification on a mutually exclusive basis. Preferably this control is resettable.

DESCRIPTION OF THE DRAWINGS

The advantages and unique features of this invention will best be understood from a reading of the following Detailed Description in conjunction with the accompanying drawings in which like numerals refer to like parts and in which:

FIG. 1 is a perspective view of the assembled nebulizer-humidifier.

FIGS. 2 is a side elevation of this device.

FIG. 3a and b show the water bag in perspective and side elevation, respectively.

FIG. 4 shows a cross-section of the preferred water bag.

FIG. 4a shows a perspective view of an alternate embodiment of the bag.

FIG- 5 is a sectional view of the bag boss.

FIG. 5a is a sectional view of an alternate boss.

FIGS. 6a, b, and c show a perspective view of the inside of the housing, a sectional view through the housing, and an elevation of the base of the housing, respectively.

FIG. 7 shows a perspective view of the outside of the housing.

FIG. 8 shows the housing and the heater insert and gasket, the combination orifice and insert, and the air valve which are assembled onto the housing.

FIGS. 9a and b show sectional views of the venturi orifice component and the baffle-diverter component, respectively, of the combination orifice and valve insert.

FIG. 10 presents fluid flow paths for the apparatus as used as a nebulizer.

FIG. 11 presents fluid flow paths for the apparatus as used as a humidifier.

DETAILED DESCRIPTION OF THE INVENTION

The objectives of this invention are realized in a medical nebulizer-humidifier apparatus for use with oxygen breathing systems, wherein the apparatus may be manufactured in reusable and disposable models. The materials of which each model is constructed will determine whether a model will be reusable or disposable with the mechanical configuration being essentially alike for both models.

The subject nebulizer-humidifier unit may be used, mutually exclusively, in the nebulizer mode and in the humidifier mode. An adjustment is made while the components are being assembled to determine in which operational mode the apparatus is to operate. The operational purpose of the apparatus can be further interchanged, but a partial disassembly and reassembly of 25

the components is required. As a nebulizer, the apparatus creates a water mist thereby the water particles produced are sized such that their mean diameters are in the 1-10 micron range. This molecular water vapor is delivered to the patient via the oxygen delivery appa- 5 ratus. As a humidifier, air or oxygen is bubbled through the water supply to generate humid air which is fed to the patient.

A flexible plastic bag 101, FIG. 1, will hold an initially sterile water supply for the unit. This bag 101 may 10 be refilled with water as needed. Located within the bag 101 is a passageway 103 which may be used to pass oxygen into the bag 101 or to draw water out of the bag 101. A hanging member 105 which can be a hook, loop, or the like, is used to support the bag 101 and the 15 entire apparatus when disconnected from the oxygen supply.

A housing unit 107 connects to the bag 101. This housing unit 107 has an oxygen supply connector 109 and a mist duct 111. The housing 107 is mountable 20 onto one side of the bag 101 as seen in FIG. 2. The housing 107 thusly extends outwardly from the outer surface of one side 115 of the bag 101 with the oxygen connector 109 and the mist duct 111 extending upwardly and outwardly, respectively. In the operating mounted position the housing 107 and its attached bag 101 are supported by the oxygen supply connector 109.

An air mix valve 113 is positioned on the outer wall of the housing 107 away from the surface of the bag 3Q 101. This valve may be operated to mix room air with the generated mist to dilute the concentration of water vapor and oxygen delivered to the patient by fixed increments.

The features of the above recited components as well 35 as the other components present in this apparatus will be discussed in detail below.

In the preferred embodiment, a flexible, collapsible plastic bag 101 is used as a water supply reservoir. This bag 101, FIGS. 3a, b, is constructed of two sheets of 4Q plastic material such as polypropylene or polyethylene heat sealed or otherwise bonded together at the edges. The size and shape of each plastic sheet comprising the bag 101 may be varied to provide various sized and shaped reservoirs. A first sheet, forming a first side 115 45 of the bag 101, FIG. 3a, is made from a flat sheet of 6 millimeters thick polypropylene material. A second sheet, forming the second side 117 of the bag 101, FIG. 3b, is also made from a sheet of 6 millimeters thick polypropylene material. This second side 117 is vac- 50 uum formed into a belled or puffed shape to provide a spacing between the walls of said first and second sides 115, 117 when the edges of these sides 115, 117 are heat sealed or otherwise joined together. Preferably each side 115, 117 has a larger portion 119 which is 55 essentially rectangular and which when mated together cooperate to hold the entire water supply. Each of the sides 115, 117 could also have a smaller rectangular portion 121 which extends from its larger portion 119 creating an air space above the water level. Located at 60 the free end of the smaller portion 121 of the bag 101 is the loop 105. This loop 105 functions as a support member for the bag 101 and is the mechanism by which the bag 101 may be hung from a support stand when not in use. The loop 105 is made as an integral part of 65 the smaller portion 121 being formed by punching out a hole of rectangular, triangular or circular shape. Plastic reinforcement may be used around the loop 105. As

suggested above, other thicknesses and other materials may also be used for one or more parts of this bag 101.

Located through the smaller portion 121 of the flat side 115, is a round hole 123 approximately 0.150 inches in diameter. Also located through the smaller portion 121 of this flat side 115, near the round hole 123 is a rectangularly shaped hole 125 of approximately 1 by 3 inches in size. These holes 123,125 may be formed by punching out the first sheet 115 before assembly. In the manufactured bag 101, these holes 123, 125 permit access to the interior of the bag 101.

Extending downwardly, in an assembled, hanging bag 101, from the round hole 123 to the bottom of the bag 101 is the passageway 103. This passageway 103 is formed by heat sealing a part of the belled side 117 to the flat side 115 of the bag 101. The passageway 103 has a semicircular cross section approximately 0.12 inches in diameter with a heat seal area of from 0.20 to 0.25 inches wide on either side. The path of this passageway 103 extends along an outer edge of the bag 101 to the bottom of the bag 101 and across the bottom. Located in the bottom section of passageway 103 are a plurality of evenly spaced slits 127. These passageway slits 127 are formed by discontinuities in the passageway's inner heat seal and permit access between the'passageway 103 and the water reservoir portion of the bag 101. The slits 127 may be formed permitting openings of approximately 0.04 inches. When the apparatus is in operation, the slits 127 provide a diffuser function. This passageway 103 may alternately be created by a channel formed in the flat side 115 which when mated with a corresponding flat portion of the belled side 117 thusly creates the passageway 103. Further the passageway 103 may also be created by the mating of the sides 115, 117, wherein both of the sides have channels which create the passageway 103 on mating. The cross-sectional shape of the passageway 103 may be varied as desired or as a result of the manner in which the passageway 103 is created.

Located about the round hole 123 and the rectangular hole 125 is a boss 129, FIG. 3a. This boss 129 is used to attach the housing 107 to the outer surface of the flat side 115 of the bag 101 and is shaped as a lazy block "nine" about the round and rectangular holes 123, 125. This boss 129 essentially forms a rail completely about the rectangular hole 125 and about the round hole 123 with the exception of a leg which if not absent would naturally bear upon the passageway 103 extending downwardly fronTthe round hole 123. The exclusion of this leg gives the boss 129 the lazy "nine" configuration. The cross section of this boss 129, FIG. 5, is essentially rectangular with a protrusion extending outwardly in a plane parallel to the flat side at the outer surface of the boss 129. This protrusion may be rounded, triangular, semicircular, or simply tapered back to the boss wall. It is used as a pressure interlock with a mating portion of the housing 107. The boss 129 may be constructed by injection molding of polycarbonate, acetal, polypropylene or polyethylene or other plastic material, as durability and disposability requires, and has the bag 101 attached to it by heat sealing, adhesives or other means. This boss 129 configuration may be changed as needed to provide a mounting and sealing element between the bag 101 and the housing 107.

Being constructed of the relatively flexible and resilient materials described above, the boss 129 will give as a housing 107 is snapped onto and off of it. Thus, the resilient properties of the material allow for an interlocking pressure fit and release with the housing 107. In some instances, however, lesser mounting and release pressure is desired. In these instances the boss 129 is structured with a living hinge 130 at its outer surface, FIG. 5a. The living hinge 130 is formed by having the boss member overlap upon itself to the outside, so that the protruding portion is overlapped to the outside of the boss 129 configuration with this overlap pointing to that base of the boss 129 which meets the bag's 101 flat side 115. This alternate structuring reduces the amount of side pressure which the boss 129 can withstand and therefore makes mounting and removal of the housing easier.

A removal tab 132 may be located on one side of the boss 129 or 130. This tab is connected to the base structure of the boss 129 or 130 by a living hinge 134. This tab is intended to be pivoted about the hinge attachment point on the boss 129 or 130 to be used as a lever to pry an interlocked housing 107 from the boss 129 or 130. The removal tab 132 is rectangularly shaped and of large enough dimensions to engage the edge of an interlocked housing 107 and to provide the mechanical advantage needed to overcome the locking pressure against the housing 107.

Where needed the bag 101 may have alternate configurations or other shapes some of which have special shapes designed to prevent kinking of the passageways. A second configuration 131 is shown in FIG. 4a. Here, there is a first flat side 133 and a second belled side 135 to the bag 131. However, in this embodiment there is only one essentially rectangular portion 131 which may have extremely rounded corners. The rectangular water reservoir portion of the bag 131 may have its sides pre-shaped or flared-in at the middle. This shape as shown in FIG. 4a, permits a redirection of the normal stress forces on the bag due to the weight of the water contained therein! With this flared edge shape, the forces are distributed radially in a uniform manner in such a way that the forces which would normally tend to compress or kink the passageways 103 and 139 are greatly reduced or completely eliminated.

A hanging flap or loop 137 extends as a semicircular extension from the end of the bag 131. This flap 137 contains a reinforced hole by which the flap 137 and thusly the bag 131 may be supported.

As in the preferred embodiment, a round hole 123 and a rectangular hole 125 exist in the upper portion of the flat side 133 of the bag 131. A passageway 139 is formed by heat sealing part of the belled side 135 to the flat side 133. This passageway 139 extends from the round hole 123 upwardly and then parts into two legs which travel along the edges of the bag 131 to its bottom. The bag 131 therefore has a dual leg passageway 139. Openings or slits 127 open the bottom leg of the passageway 139 to the interior or water reservoir portion of the bag 131. A boss 141 of like construction to the preferred boss 129 is heat or otherwise sealed about the holes 123,125. This boss 141 is of reflected image configuration to the boss 129, i.e., the open leg looks upwardly instead of downwardly.

While two embodiments of this bag 101, 131 have been discussed above, other embodiments can exist without departing from the scope of the invention. For example, the first bag 101 could have a dual leg passageway 139 formed in it. Any bag could have the flared edge configuration. The size and shapes of the

parts may be varied while still maintaining their functions. Moreover, the size and thickness of the materials used will vary as a function of the intended size and durability of the water reservoir. Typically the bag 101 5 is designed to hold up to 500 cubic centimeters of water and will have "500 cc", "250 cc", and "fill line" indications embossed on the sides. For a bag capable of holding this volume the overall dimensions of the bag may be 8 to 11 inches long by 5 to 6 inches wide with

10 the belled side protruding about % to 2 inches from its mating flat side.

Each embodiment of the bags 101,131, FIGS. 3a, 4a. respectively, may have a pressure sensitive, adhesive coated or heat sealed rectangular cover patch 143

15 which protects the boss 129, 141 and the access holes 123,125 and maintains the sterility of the inside of the bags 101, 131 before the apparatus is first assembled. This cover patch 143 is also useful for keeping the water from escaping from the bags 101,131 when they

20 are supplied prefilled with sterile water.

A housing 107, FIG. 6a, holds other components comprising the nebulizer-humidifier. Included among the components is a combination venturi orifice and valve insert 145, a water heater insert 147 and a gasket

25 149. The housing structure is injection molded of polycarbonate, acetal, polypropylene or polyethylene depending upon its intended length of use. The more durable materials are used for more permanent models. In the preferred embodiment, housing 107, FIGS. 6a,

30 b, c, are injection molded of polycarbonate plastic in an essentially truncated pyramidal shape. The housing walls are mounted upon a rectangular base 151, FIG. 6a, which steps out from the walls and then turns at a right angle to extend away from the end of the housing

35 walls. With the housing 107 attached to the bag 101, the housing 107 presents top 153, bottom 155 and side 157, 159 walls and an outer side 161. The walls of the base 151 have intermittent protruding surfaces 162 located in the inner base 151 walls. At each protrusion

40 162 is located a concave undercut 163. Each of these undercuts 163 extend into the base 151 inner face to form a cavity approximately 0.030 inches deep and 0.145 inches wide. These undercuts 163 engage the boss 129 protrusions to hold the bag 101 onto the hous

45 ing 107. The stepout of the base 151 from the walls 153, 155,157, 159 of the housing provides a shoulder or seating surface 165 at the jointure of the base 151 and walls 153, 155, 157, 159. A spacing of about 0.19 inches exists between the undercut 163 and the seating

50 165.

The housing 107 has four chambers 167, 169, 171 and 173. The first chamber 167 is of truncated narrow pyramidal shape and extends into the housing from the base to the outer side 161. This chamber 167 is located

55 next to the first side wall 157 so as to communicate with the round hole 123 in the bag 101 when said bag 101 is mounted to the housing 107. A channel 175 may run longitudinally down the center of the top 153 inner wall and continues partially down the center of the

60 outer side 161 inner wall of this chamber 167.

A rectangular section of the base 151 and bottom 155 wall of the housing is cut out along the cross section centerline of the chamber 167. This cutout 177 extends to about mid-depth of the chamber and is ap

65 proximately equal in width to the bag passageway 103 leading from the round hole 123.

The second chamber 169 adjoins the first chamber 167 and is cylindrically shaped to extend into the hous7

ing 107 from base seat 165 plane to the outer side 167. This chamber 169 extends parallel to the first chamber 167 at about the nominal center of the housing 107. With the housing 107 secured to the boss 129, this second chamber 169 communicates with the bag's 5 rectangular hole 125.

Located through the wall adjoining the first 167 and second 169 chambers is square transfer portal 179 being about 0.05 inches on a side. This portal extends parallel to the base seating 165 plane and connects a 10 centerline of the first chamber 167 with a centerline of the second chamber 169.

Extending partially about the opening to the second chamber 169 and outwardly from the plane of the base seat 165 is a first venturi spacer 181. This spacer 181 is 15 a curved plate which extends from the transfer portal 179 in a clockwise arc of about 180° when looking at the base seat 165.

Also extending partially about the second chamber 165 opening is a second venturi spacer 182. This sec- 20 ond spacer 182 is a curved plate which extends from the end of the first spacer 182 in a clockwise arc of about 120° when looking at the base seat 165. This second spacer 182 does not extend as far above the base seating plane 165 as does the first spacer 181. As 25 will be further discussed, the difference in the heights of the two venturi spacers 181, 182 provides the venturi chamber spacing in the venturi nozzle of the assembled housing 107.

The oxygen supply connector 109 protruding from 30 the top wall 153 of the housing 107, includes an extension tube 109a, with a pressure fit head 1096 and a locking nut 109c. The head 1096 and lock nut 109c are sized to receive a standard sized pressure line from an oxygen supply flow meter. The extension tube 1096 is 35 provided passageway into the pressure end of the second chamber 169, the end nearest the outer side 161, by a circular oxygen portal 183 extending through the housing top wall 153 and the outer side 161.

The third chamber 171, FIG. 6b, extends parallel to 40 the first two chambers 167,169, from the base seat 165 plane to the outer side 161 of the housing 107. This chamber borders the top wall 153 and second side wall 159 and has a relieved rectangular cross section with the relief being provided by the intrusion of the walls of 45 the second chamber 169 into a corner of the rectangle. The breadth of this rectangle is defined by the distance between the walls of the first chamber 167 and the second side wall 159. The length of this rectangle is defined by the distance from the top wall 153 of the 50 housing to an inner partition wall 185. This partition wall 185 extends parallel to the housing top wall 153 and tangentially to the second chamber 169, from that part of the second chamber's 169 wall away from the housing top wall 153 to the housing second side wall 55 159. With the housing 107 positioned on the bag boss 129 this chamber 171 communicates with the bag rectangular hole 125.

Tubular mist duct 111 exhausts this third chamber 171 through the second side wall 159 by connecting to 60 a circular mist exhaust port 187 through the wall 159.

A pressure relief valve structure 189 extends into the housing's outer side 161 at the back of this third chamber 171. This relieve valve structure 189 is of standard design. Included is a rubber gasket 190 which seats in the bottom of the relief valve cavity 189 to provide the pressure release mechanism. An insert positionable into the relief valve cavity 189 against the gasket will be

discussed below during the discussion of the air mix valve 113.

The fourth chamber 173 adjoins each of the other chambers 167, 169, 171, is essentially rectangularly shaped, and extends parallel to the other chambers 167, 169, 171. This chamber is defined by the meeting of the partition wall 185, the second side 159, and bottom walls, the outer side 161 and the adjoining first chamber 167 wall. Extending through the rear of this chamber, i.e. through the outer side 161, is an air mix portal 191. This portal has a tapered, flanged mouth at the outer side 161 of the housing 107.

Situated partially about the pressure relief valve structure 189 on the outer side 161 of the housing 107 is a curved limit plate 193, FIG. 7. This plate transcribes an angle of approximately 80° and is used to limit the rotational operation of the air mix valve 113. Protruding from the inner curvature of this limit plate 193, in the center portion of the curve is a tab 194. This tab 194 extends outwardly from the top of the limit plate 193 in a plane parallel to housing outer wall 161. The purpose of this tab 194 is to interfere with a portion of the air mix valve 113 when the valve has been rotated into position to keep the air mix valve 113 from pulling out of the housing 107.

Air mix valve 113, FIGS. 7,8, includes a flat, pie-sectional plate having three circular protrusions 195,197, 199 on the underside of the valve 113, each being spaced along its outer arc. A thumb plate 201 protrudes outwardly from the center of the valve's 113 top side. Extending from the underside of the valve 113 at the acute angle of pie-section is the pressure relief valve insert 203. This insert 203 mates with the valve structure 189 in the housing's outer side 161 to seat against the gasket 190. A flange extends partially about this insert 203. Because of the circular configuration, the relief valve permits pivoting of air mix valve 113 to locate one of the protrusions over the air mix portal 191. The first protrusion 195 is a circular disk and closes off the air mix portal 191 when positioned over it. The second protrusion 197 has an included circular opening which permits an opening and access to a portion of the air mix portal 191 when this protrusion 197 is positioned over the air mix portal 191. The third protrusion 199 has an included circular opening which permits lesser opening and access of a lesser portion of the air mix portal 191 when this protrusion 199 is positioned over it. Located at the relief valve insert 203 area of the plate is a small through hole 205. Escaping air passing through this hole 205 creates a whistling sound when the relief valve operates. With the air mix valve protrusions 195,197 or 199 in position at the air mix portal 191 the interfering tab 194 is mated with the insert 203 flange to secure the air mix valve 113 to the housing 107.

A tubing adapter 207, is insertable into the mist duct 111 for connecting to a range of from 0.110 inches to 0.402 inches diameter tubing.

Insertable into the first chamber 167, in a pressure fit, is the heater unit 147, FIG. 8. This unit is a resistance wire wound heater element 209 as manufactured by Watlow Inc. having thermostatic control for operation between 90° and 110° F. The heater element 209 is rectilinearly shaped and is fiberglass reinforced and encapsulated to proper dimensions for use. The element 209 is encapsulated in biocompatible insulation such as silicone rubber to form a truncated narrow pyramidal outer shape. Molded into the outer surface