US3807445A

US3807445A - Audible pressure relief valve for medical humidifier

Info

Publication number: US3807445A
Application number: US00264349A
Authority: US
Inventors: Phee C Mc
Original assignee: American Hospital Supply Corp
Current assignee: American Hospital Supply Corp; Baxter International Inc
Priority date: 1972-06-19
Filing date: 1972-06-19
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30
Also published as: BE797605A; IT980078B; CA975650A; GB1433263A; FR2191048B1; ES413665A1; JPS4951629A; AU5348773A; FR2191048A1

Abstract

An audible pressure relief valve for a medical humidifier used in inhalation therapy. This valve relieves pressure from the humidifier when there is a kink or obstruction in a humidified oxygen tube leading to a patient''s mask, nasal cannula or tent. The valve has a rubber disc that is dimensionally tuned to vibrate against a valve seat and emit an audible sound over a wide range of oxygen flow rates. This valve audibly vibrates at gas flow rates of 3 to 15 liters per minute and pressures of 1 to 5 psi above atmospheric pressure.

Description

I United States Patent 11 1 1111 3,807,445 McPhee Apr. 30, 1974 [54] AUDIBLE PRESSURE RELIEF VALVE FOR 3,633,613 1/1972 Julow 137/512.3 MEDICAL HUMIDIFIER 3,572,660 3/1971 Mahonm. 261/78 A V 1,493,570 5/1924 Slate 116/70 Inventor: Charles J- McPhee, y ar, Cahf. 2,473,912 6/1949 Schwinn 137/557 x 3,351,088 11/1967 Jensen 137/557 X [73] Assgnee' 'f Hospna' supply 711,385 10/1902 Coyle 126/388 ux Corporatlon, Evanston, Ill. I [22] Filed: June 19, 1972 I Primary Examiner '-Robert G. Nilson [21] Appl. No.: 264,349

[57] ABSTRACT 52 US. Cl 137/557, 116/70, 128/1465, audible P relief valve for a medical humidi- 128/188 137/525 fier used in inhalation therapy. This valve relieves 51 1111. c1. Fl6k 15/14 Pressure from the humidifier when there is a kink or [58] Field 61 Search 137/227, 228,525, 525.3, Obstruction in a humidified Oxygen tube leading to a 137/557; 1 16/34 R, 70, l 12; 126/388; patients mask, nasal cannula or tent. The valve has a 128/1424, 1465, 138 rubber disc that is dimensionally tuned to vibrate 1 v against a valve seat and emit an audible sound over a l 56] References Cited wide range of oxygen flow rates. This valve audibly vi- UNITED STATES PATENTS brates at gas flow rates of 31015 liters per minute and pressures of l to 5 psi above atmospheric pressure. 3,196,924 7/1965 1(aminga.'. 137/525 X 1,506,012 8/1924 Lewis 137/525 19 Claims, .6 Drawing Figures 3&

BACKGROUND Inhalation therapy has been used more and more in recent years for treating emphysema and other lung and respiratory diseases, as well as postoperative treatment and cardiac patient care. One form of inhalation therapy involves mixing a breathable gas such as air or oxygen with a liquid. This humidified gas is supplied to a mask, nasal cannula, or tent, where it is breathed by the patient. A conventional medical humidifier system includes a dry gas source such as a portable oxygen tank or central oxygen supply system of a hospital, coupled with a container of the humidifying liquid. Humidification is accomplished by atomizing liquid into the gas or by bubbling the gas through the liquid. v

There has been a problem in the past with medical humidifiers in reliably determining when humidified gas was inadvertently cut off from the patient. This often happened when the oxygen tube leading to the patients mask became kinked. Thus, while it appeared that the patient was still receiving the oxygen or other humidified gas he was in effect cutoff from his inhalation therapy treatment.

a It has been proposed touse various check valves or pressure relief valves in a humidifier to avoid an excessive pressure buildup that might break tubing joints, etc. from their connections. When such a pressure relief valve does open to release pressure it-is important that the physician or nurse knows about it. This is so he can correct the obstruction causing the pressure buildup and quickly get the patient back on his prescribed inhalation therapy. A previous inhalation therapy apparatus involved a spring biased check valve that exhausted released gas into a knife edge whistle such as a common toy whistle. However, the gas flow rates in a medical humidifier are sometimes too slow to cause a noise with such whistle. Also, at very low pressures of between 2 and 4 psi above atmospheric these knife edge whistles do not always reliably operate.

SUMMARY OF THE INVENTION I have overcome the problemsof previous medical humidifiers by providing a special audible pressure relief valve for the humidifier. This special relief valve includes a thin rubber disc that is dimensionally tuned to simultaneously release pressures a low pressure range of between 1 and psi above atmospheric and also to audibly vibrate at this pressure with low gas flow rates of from 3 to liters per minute. This rubber disc is gently urged against a valve seat by a retention post of the special valve. The structure and operation of this valve will become more apparent with reference to the following attached drawings.

THE DRAWINGS FIG. 1 is a front elevational view of the special pressure relief valve shown encased in an adapter that connects a dry gas source, a liquid supply source and a tube leading to the patient;

FIG. 2 is anenlarged front elevational view of the adapter prior to its connection of the elements listed above;

FIG. 3 is a further enlarged sectional view of the adapter showing the various passages of the adapter and how the special pressure relief valve is coordinated therein;

.FIG. 4 is a right side view of a retention plug of FIG. 3, shown before it is assembled to a body of the adapter;

FIG. 5 is a left side view of the valve of FIG. 3, shown with the retention plug removed and viewing the flexible resilient disc fitting against a valve seat; and

FIG. 6 is a further enlarged fragmentary sectional view of the resilient disc showing how it audibly vibrates against a valve seat at low flow rates of gas.

THE DETAILED DESCRIPTION Turning now to the drawings mentioned above, the medical humidifier apparatus includes a dry gas source 1 that is shown terminating in a threaded nipple 2. The term dry gas is used to indicate a breathable gas such as air or oxygen, etc., before it is humidified with a special humidifier. Connected to this nipple is a screw cap 4 that is swivelly mounted on adapter 5. A lower end of this adapter 5 connects directly to a liquid supply 'bottle 6 through a port in cap 7 of the bottle. The

adapter has a tubular side arm 8 that connects with a patients supply tube 9 which leads to a mask 10. Thus, after gas is fed from dry gas supply source 1 through adapter 5 and into'bottle 6 where it is humidified it is thereafter fed out through patients supply tube 9 to mask 10. The patient then breathes the humidified gas during the inhalation therapy procedure.

Should the patients supply line 9 become kinked or otherwise obstructed the gas pressure in dry gas source 1 will begin to build up until a special pressure relief disc 11 is forced to open and the excess gas is vented to the atmosphere. It is to this special pressure relief valve and its relationship to adapter 5 that the present invention relates.

The adapter itself prior to connection with dry gas source 1 and bottle 6 is shown in enlarged view in FIG. 2. The special connection of this adapter to cap 5 is explained in more detail in my co-pending application entitled Port System for Medical Humidifier Container filed 19 June 1972, Ser. No. 264,315. When adapter 5 is connected in the bottle 6 through cap 7 it communicates with a defoaming device and a gas-liquid mixing column. These two features are explained in my copending applications respectively entitled Defoaming Device for Medical Humidifier" filed 19 June I972, Ser. No. 264,350; and Mixing Column for Medical Humidifier and Method of Humidifying Inhalable Gases filed 19 June 1972, Ser. No. 264,314.

In FIGS. 1 and 2 the resilient pressure relief disc is shown only in schematic dotted line. In the further enlarged sectional view of FIG. 3 this resilient disc 11 is shown as it relates to the internal structure of adapter 5. This adapter 5 includes a body member 15 with an upper flange 16 for connecting inside screw cap 4 and a lower snap fit flange 17 for fitting inside cap 7 of bottle 6. Extending longitudinally through body 15 of the adapter is a dry gas passage 18. Along a lower portion of the adapter this dry gas passage 18 is defined by a tubular dry gas tube 19. The adapter 15 also includes a tubular outer wall 20 at a lower portion of its body. As shown in FIG. 3 the

tubes

19 and 20 are located on a common longitudinal axis and define an annular humidified gas passage 21 therebetween. I-Iumidified gas passage 21 communicates with a passage 22 in a tubular side arm 8 of the body. This passage 22 feeds gas into a patients tube 9.

The dry gas passage 18 and the interconnecting

humidified gas passages

21 and 22 mentioned above cooperate to supply the bottle 6 with a dry gas such as oxygen and carry off humidified oxygen. Until there is a kink in the patients tube or otherwise some abnormal pressure buildup these passages are all that are needed for conducting the gases.

However, when the patients tube becomes kinked or there is some pressure buildup the special relief valve shown to the left of FIG. 3 comes into play to release the excess pressure. Referring to this section of FIG. 3 the body 15 includes a port 23 that communicates with the humidified gas passage 21. The port also is in communication with a relief cavity 24 that is defined by a ledge surface 25 and a shoulder surface 26. This relief cavity provides an area into which the resilient disc 11 can flex without obstruction when urged against an annular valve seat 27 surrounding the relief cavity 24. As seen in FIG. 3 the resilient rubber disc fits against valve seat 27 and is aligned with port 23 by an upstanding flange 28 around the valve seat. Preferably flange 28 has a series of guide ribs illustrated by 29 and 30. These guide ribs keep the flexible rubber disc 11 aligned on the valve seat and reduce friction and drag during audible vibrations by contacting an edge of the rubber disc.

Fitting across the flange 28 is a retention plug 32. This plug includes a baffle plate 33 with a hole 34. The baffle plate is attached to a depending skirt'35 that telescopically fits into flange 28. The skirt 35 and flange 28 include an innerconnecting annular groove and

rib structure

36 and 37 that snap fit together to hold the plug to the flange. The baffle plate of the plug has an integral retention post 38, which extends to a distal end 39 that includes a protruding rounded pressure surface 40 with a radius of from 0.010 to 0.050. This retention post 38 engages a center portion of the imperforate resilient disc 11 and gently urges it against valve seat 27. The posts small rounded pressure surface does not substantially restrict the flex characteristics of the resilient disc during audible vibration under low pressure and low volume gas flow.

When there is a kink in the patient line 9 or a blockage therein. disc 11 will open at some pressure between 1 and psi over atmospheric. At this pressure and flow rate of between 3 and liters of gas per minute through port 23 cause the rubber disc 11 to audibly vibrate against seat 27. This audible vibration signals a nurse or physician that the patients supply line has become blocked.

I have found that a natural rubber disc of material 0.020 to 0.130 inch thick and with a diameter of 0.200 to 0.600 inch will audibly vibrate at these low pressures and flow rates when gently urged by retention post 38 against the valve seat 27. Preferably the rubber disc has a thickness of 0.050 and a diameter of 0.350. I have also found that when the vent hole 34 in baffle plate 33 is from 0.030 to 0.100 inch diameter and the baffle plate is spaced from 0.100 to 0.200 inch from the resilient disc 11 there is a harmonic relationship set up between the vibrating rubber disc and the hole 34. This increases the intensity of the audible sound.

The special construction of the audible pressure relief valve makes for easy assembly during manufacture. The rubber disc is fitted into a pocket of the flange 28 and retention plug 32 is simply snapped into place. It can also be heat sealed in place to more firmly lock the plug in place. The entire structures of the adapter body and retention plug are injection molded of a polypropylene thermoplastic material. This method of manufacture is sufficiently inexpensive so that the entire adapter, pressure relief valve and connected bottle 6 can be discarded after a single use on a single patient. This reduces the risk of cross contamination between patients.

With my invention 1 have provided a special audible pressure relief valve that simultaneously performs two functions at a low gas flow rate and a low pressure. It both reliably releases the pressure buildup and audibly signals a nurse or physician to come and correct the blocked or kinked tube leading to the patient.

In the foregoing specification I have used a specific example to illustrate my invention. However, it is understood by those skilled in the art that certain modifcations can be made to this example without departing from the spirit and scope of the invention.

I claim:

1. A low-pressure, audible relief valve-and-gas administration adapter for use in a gas inhalation therapy system in which gas is to be constantly administered to a patient, comprising in combination:

a body having passage means therethrough and including means for connecting the passage to a pressurized source of treatment gas and means for connecting the passage means to a gas treatment means, an elongated through-passage extending from end-to-end and including means at one end for connection to a pressurized gas source and means at the other end for connection to gas treatment means; the body including second passage means. including means for communication with the treated gas for constantly directing treated gas to a patient; and a low-pressure relief valve assembly connected in parallel communication with said second passage means for relieving excessive pressures therein and audibly aprizing one of the high pressures in said second passage means and inoperativeness of the system, said valve assembly including pressure-relief cavity means in said body opening to said second passage means and subject to pressures therein; a valve seat surrounding said pressure-relief cavity means; a resilient pressurerelief valve disc displacably seated at one side on said valve seat and closing said cavity, said body including atmospheric vent means open to the opposite side of said disc for relieving pressure in said second passage means when the valve disc is displaced; said body including post means having a relatively small area engaging the opposite side of said valve disc and normally biasing the valve-disc onto the seat, said disc being engaged by said post to permit surrounding portions of the disc to be vibrationally displaced by pressures over a predetermined value in said second passage means, the disc being constructed and arranged to vibrate at relatively low pressures and tuned to emit an apparent audible frequency when excessive pressures are relieved.

2. The combination as set forth in claim 1 wherein the resilient disc includes a thin-body which audibly vibrates at relief pressures of 1-5 psi above atmospheric.

3. The combination as set forth in claim 1 wherein the resilient pressure relief disc includes a thin body which will audibly vibrate at gas flow rates in the range of 3 to liters/minute.

4. The combination as set forth in claim 1 wherein the body member valve seat is annular and flat, surrounding the pressure relief cavity, and the resilient disc abutsagainst the seat and is bowed into the cavity.

5. The combination as set forth in claim 4 wherein the valve body includes an upstanding flange surrounding the valve seat to retain the disc in alignment with the relief port and the body includes at least one guide rib on the interior of the upstanding flange for engagement of an edge surface of the resilient disc.

6. The combination as set forth in claim 1 wherein the post means includes a rounded end urging the resilient disc against the valve seat for permitting radial areas free to vibrate.

7. The combination as set forth in claim 6 wherein the terminal end of the post means has a cross sectional area substantially smaller than the cross sectional dimensions of the relief cavity means and the post contacts the resilient disc at a location approximately at a center of the body port.

8. The combination as set forth in claim 7 wherein the resilient disc is one piece and imperforate.

9. The combination as set forth in claim 7 wherein the post means and is convex end contacts a center portion of the resilient disc and the roundedend provides a pressure surface about which the resilient disc can flex and vibrate. I

10. The combination as set forth in claim 9 wherein the pressure surface of said rounded post means has a radius of between 0.010 and .050 inch for restricting the area of contact between the post means and valve disc.

11. The combination as set forth in claim 1 wherein the body includes retention means integral with the post means, the retention means includes a baffle plate having a hole therethrough with a cross sectional area equivalent to a round hole of a diameter from .030 to 0.100 inch.

12. The combination as set forth in claim 11 wherein the baffle plate is spaced a distance of from 0.100 to 0.200 inch from the resilient valve disc so as to create a harmonic whistle through the combination ifthe vibrating resilient disc and the baffle plates hole.

13. The combination as set forh in claim 11 wherein there is a depending skirt integral with the baffle plate and the body has an annular flange surrounding the port, which skirt and flange fit together in a telescopic relationship; and the combination includes interengaging snap fit means for holding the skirt and flange together, said baffle plate and snap fit means positioning the post means into engagement with said valve disc.

14. The combination as set forth in claim 13 wherein the interengaging snap fit means includes an annular groove and rib structure on the skirt and flange.

15. The combination as set forth in claim 1 wherein the resilient disc is rubber and has a thickness from 0.020 to 0.130 inch and a diameter of from 0.200 inch to 0.600 inch.

16. A combination low pressure audible relief valve and adaptor for use in gas inhalation therapy comprising: a molded body including an elongated through passage extending from end-to-end and including means at one end for connection to a pressurized gas source and means at the other end for connection to gas treatment means; a second passage in said body surrounding the first-mentioned passage and including a tubular side arm in communication therewith for directing treated gas to a patient, an audible, pressure relief valve assembly connected to said second passage in parallel communication with the second passage and subject to the pressures existing therein, said valve assembly comprising a pressure relief cavity in direct communication with said second passage, a valve seat surrounding said cavity in spaced lateral relation from said second passage, a relatively small, flat resilient disc engaged at one .side on said seat and functioning to retain pressures below a predetermined value in said second passage, said body including a wall surrounding said valve seat and disc and an apertured baffle wall communicating with the atmosphere exposing the other side of the disc to atmospheric pressure, said baffle wall including an axial post extending toward said valve disc and engaging the other side thereof and normally biasing it into said pressure relief cavity, said post having a rounded end arching the disc onto the seat and in an direction the disc moves when pressure is relieved in the second passage, said disc being constructed and arranged to emit an audible frequency when displaced from the seat at pressures over a predetermined value.

17. The combination as set forth in claim 16 wherein the resilient valve disc is and rubber of from 0.020 inch to 0.130 inch thick and with a diameter of from 0.200 inch to 0.600 inch.

18. The combination as set forth in claim 16 wherein the resilient disc'is spaced from the apertured baffle wall so that it audibly vibrates at a release pressure of l-5 psi above atmospheric pressure, the baffle wall being spaced a distance of from 0.100 0.200 inch from the valve disc and containing a vent-opening having a cross sectional area equivalent to that of a round hole with a diameter from .030 -0.lO0 inch.

19. The combination as set forth in claim 16 wherein the resilient disc is spaced from the apertured baffle wall so that it will vibrate over the range of 3 to 15 liters/minute of gas passing through thepressure relief cavity, the baffle wall being spaced a distance of from 0.100 -0.200 inch from the valve disc and containing a vent-opening having a cross-sectional area equivalent to that of a round hole with a diameter from 0.030 -O.100 inch.

Claims

1. A low-pressure, audible relief valve-and-gas administration adapter for use in a gas inhalation therapy system in which gas is to be constantly administered to a patient, comprising in combination: a body having passage means therethrough and including means for connecting the passage to a pressurized source of treatment gas and means for connecting the passage means to a gas treatment means, an elongated through-passage extending from end-to-end and including means at one end for connection to a pressurized gas source and means at the other end for connection to gas treatment means; the body including second passage means including means for communication with the treated gas for constantly directing treated gas to a patient; and a lowpressure relief valve assembly connected in parallel communication with said second passage means for relieving excessive pressures therein and audibly aprizing one of the high pressures in said second passage means and inoperativeness of the system, said valve assembly including pressure-relief cavity means in said body opening to said second passage means and subject to pressures therein; a valve seat surrounding said pressure-relief cavity means; a resilient pressure-relief valve disc displacably seated at one side on said valve seat and closing said cavity, said body including atmospheric vent means open to the opposite side of said disc for relieving pressure in said second passage means when the valve disc is displaced; said body including post means having a relatively small area engaging the opposite side of said valve disc and normally biasing the valve-disc onto the seat, said disc being engaged by said post to permit surrounding portions of the disc to be vibrationally displaced by pressures over a predetermined value in said second passage means, the disc being constructed and arranged to vibrate at relatively low pressures and tuned to emit an apparent audible frequency when excessive pressures are relieved.

3. The combination as set forth in claim 1 wherein the resilient pressure relief disc includes a thin body which will audibly vibrate at gas flow rates in the range of 3 to 15 liters/minute.

4. The combination as set forth in claim 1 wherein the body member valve seat is annular and flat, surrounding the pressure relief cavity, and the resilient disc abuts against the seat and is bowed into the cavity.

9. The combination as set forth in claim 7 wherein the post means and is convex end contacts a center portion of the resilient disc and the rounded end provides a pressure surface about which the resilient disc can flex and vibrate.

12. The combination as set forth in claim 11 wherein the baffle plate is spaced a distance of from 0.100 to 0.200 inch from the resilient valve disc so as to create a harmonic whistle through the combination if the vibrating resilient disc and the baffle plate''s hole.

16. A combination low pressure audible relief valve and adaptor for use in gas inhalation therapy comprising: a molded body including an elongated through passage extending from end-to-end and including means at one end for connection to a pressurized gas source and means at the other end for connection to gas treatment means; a second passage in said body surrounding the first-mentioned passage and including a tubular side arm in communication therewith for directing treated gas to a patient, an audible, pressure relief valve assembly connected to said second passage in parallel communication with the second passage and subject to the pressures existing therein, said valve assembly comprising a pressure relief cavity in direct communication with said second passage, a valve seat surrounding said cavity in spaced lateral relation from said second passage, a relatively small, flat resilient disc engaged at one side on said seat and functioning to retain pressures below a predetermined value in said second passage, said body including a wall surrounding said valve seat and disc and an apertured baffle wall communicating with the atmosphere exposing the other side of the disc to atmospheric pressure, said baffle wall including an axial post extending toward said valve disc and engaging the other side thereof and normally biasing it into said pressure relief cavity, said post having a rounded end arching the disc onto the seat and in an direction the disc moves when pressure is relieved in the second passage, said disc being constructed and arranged to emit an audible frequency when displaced from the seat at pressures over a predetermined value.

18. The combination as set forth in claim 16 wherein the resilient disc is spaced from the apertured baffle wall so that it audibly vibrates at a release pressure of 1-5 psi above atmospheric pressure, the Baffle wall being spaced a distance of from 0.100 - 0.200 inch from the valve disc and containing a vent-opening having a cross sectional area equivalent to that of a round hole with a diameter from .030 -0.100 inch.

19. The combination as set forth in claim 16 wherein the resilient disc is spaced from the apertured baffle wall so that it will vibrate over the range of 3 to 15 liters/minute of gas passing through the pressure relief cavity, the baffle wall being spaced a distance of from 0.100 -0.200 inch from the valve disc and containing a vent-opening having a cross-sectional area equivalent to that of a round hole with a diameter from 0.030 -0.100 inch.