WO2016108129A1

WO2016108129A1 - Pneumatically sealed exhalation valve

Info

Publication number: WO2016108129A1
Application number: PCT/IB2015/059711
Authority: WO
Inventors: Kelley CULLEN; Daniel Morrison
Original assignee: Koninklijke Philips N.V.
Priority date: 2014-12-30
Filing date: 2015-12-17
Publication date: 2016-07-07

Abstract

An exhalation valve employs a valve body (21), a diaphragm (22) and a leak orifice (30). Valve body (21) encloses an pneumatic air passage (28) of patient exhalation air and a pneumatic damping chamber (29) of compressed air. Diaphragm (22) seats within the valve body (21) isolating the pneumatic damping chamber (29) from the pneumatic air passage (28). Leak orifice (30) extends through the valve body (21) into the pneumatic damping chamber (29). In operation, leak orifice (30) cyclically regulates a volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) cyclically regulating a flow of patient exhalation air through the pneumatic air passage (28).

Description

PNEUMATICALLY SEALED EXHALATION VALVE

FIELD OF THE INVENTION

The present invention generally relates to a pneumatically sealed exhalation valve for a ventilator. The present invention specifically relates to a prevention of uncontrollable oscillations of the exhalation valve.

BACKGROUND OF THE INVENTION

Generally, in a ventilator, the exhalation valve controls the gas from the patient. More particularly, the exhalation valve restricts or eliminates a flow of gas during an inspiratory phase of a breath, and controls the flow and a pressure of the gas during an exhalation phase of a breath. However, one of the main problems encountered when implementing an exhalation valve in a ventilator is uncontrollable oscillations. These oscillations may create pressure and flow oscillations at the patient causing discomfort and volume delivery inaccuracies.

For example, FIG. 1 A and FIG. IB generally illustrates an opening and a closing of an exemplary exhalation valve 10 pneumatically sealed from a patient by a valve body 11 enclosing an pneumatic air passage 16 and a pneumatic dampening chamber 17 isolated from pneumatic air passage 16 by a diaphragm 13 seated within valve body 11 via a seat 18. In normal operation, a piston arm 15 of actuator 14 rhythmically presses and releases diaphragm 13 against a wall 12 segregating an inlet and an outlet of pneumatic air passage 16. This cyclical motion by diaphragm 13 is opposed by pneumatic dampening chamber 17, which results in a regulation of the patient exhalation air through pneumatic air passage 16.

However, when opening (FIG. 1 A) or closing (FIG. IB) exhalation valve 10 through normal operation, transient forces and pressures develop which may excite exhalation valve 10 to oscillate incontrollable. Because actuator 14 is normally rounded for better seating of diaphragm 13 against a valve seat 18, a point of contact is minimized resulting in a relatively unstable exhalation valve 10. Further, because the opposing forces on the diaphragm 13 consist of a point of contact and distributed air load, during operation, oscillations may start after a transient event.

These oscillations cause significant and numerous problems. First, the oscillations may be felt by the patient. Second, in a feedback loop for pressure control via an actuation rate of diaphragm 13, measured pressure readings will show the oscillations resulting in improper feedback and therefore improper control of the patient airway.

Some known solutions to the oscillations problem employ additional weight to diaphragm 13, which slows exhalation valve 10. While this is a partial solution, the additional weight does not fully solve the problem.

Alternatively, diaphragm 13 has been rigidly attached to piston arm 15 of actuator 14, resulting in sealing problems because of alignment issues between valve seat 19 and a hard-mounted diaphragm 13. This solution is more expensive in terms of materials costs and more labor intensive to ensure a proper seal/proper operation.

SUMMARY OF THE INVENTION

The present invention proposes a leak orifice extending into the pneumatic dampening chamber. Generally, to open and close the exhalation valve, the leak orifice moves and changes the volume of the pneumatic dampening chamber of the exhalation valve. The leak orifice allows air to move in and out of the pneumatic dampening chamber as the diaphragm moves while the exhalation valve is opening and closing. The leak orifice is large enough that the exhalation valve may still open/close fast enough on behalf of the patient, but the leak orifice is small enough to stop high frequency oscillations of the exhalation valve. The leak orifice may be constant, may be controlled by a valve to have a variable leak or may have to ability to be entirely shut off.

One form of the present invention is an exhalation valve employs a valve body, a diaphragm and a leak orifice. The valve body encloses an pneumatic air passage of patient exhalation air and a pneumatic damping chamber of compressed air. The diaphragm seats within the valve body isolating the pneumatic damping chamber from the pneumatic air passage. The leak orifice extends through the valve body into the pneumatic damping chamber. In operation, the leak orifice cyclically regulates a volume of the compressed air within the pneumatic damping chamber responsive to the diaphragm cyclically regulating a flow of the patient exhalation air through the pneumatic air passage.

For purposes of the present invention, terms of the art including, but not limited to, "valve body", "pneumatic air passage", "patient exhalation air", "pneumatic damping chamber", "compressed air", "diaphragm", "flow regulation" and "volume regulation" are to be interpreted as understood in the art of the present invention and as exemplary described herein.

For purposes of the present invention, the term "leak orifice" broadly encompasses an orifice, an aperture, a hole or the like extending through the valve body with a configuration and dimensions to regulate a volume of compressed air within the pneumatic dampening chamber.

The foregoing form and other forms of the present invention as well as various features and advantages of the present invention will become further apparent from the following detailed description of various embodiments of the present invention read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the present invention rather than limiting, the scope of the present invention being defined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 A and IB illustrate cross-sectional views of an exemplary embodiment of an exhalation valve as known in the art. Note the cross-sections of a diagram and an actuator are not cross-hatched for clarity in identifying the diagram and the actuator in FIGS. 1 A and IB.

FIGS. 2 A and 2B illustrate cross-sectional views of an exemplary embodiment of an exhalation valve in accordance with the inventive principles of the present invention. Note the cross-sections of a diagram, a disk, a seat and an actuator are not cross-hatched for clarity in identifying the diagram, the disk, the seat and the actuator within FIGS. 2A and 2B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODFMENTS

To facilitate an understanding of the present invention, exemplary embodiments of the present invention will be provided herein directed to a pneumatically sealed exhalation valve 20 as shown in FIG. 1. From the description of the exemplary embodiments of the present invention, those having ordinary skill in the art will appreciate how to make and use the present invention for numerous variations of an exhalation valve in accordance with the inventive principles of the present invention.

Referring to FIGS. 2A and 2B, generally, an opening and a closing of an exhalation valve 20 of the present invention pneumatically sealed from a patient is achieved by a valve body 21 enclosing an pneumatic air passage 28 and a pneumatic dampening chamber 29 isolated from pneumatic air passage 28 by a diaphragm 22 seated within valve body 21. More particularly, diaphragm 22 is seated within a seat 24 having an O-ring (not shown) and an actuator 25 having a rounded piston 26 secured to disk 23 for allowing diaphragm 22 to "gimble" and lower bias flow through pneumatic air passage 28. Actuator 25 is movably coupled to valve body 21 by a plate 27.

In normal operation, piston arm 26 of actuator 25 rhythmically presses and releases diaphragm 22 against a valve body wall segregating an inlet and an outlet of pneumatic air passage 28. This cyclical motion by diaphragm 22 is opposed by pneumatic dampening chamber 29, which results in a regulation of the patient exhalation air through pneumatic air passage 28. In practice, an actuation rate of actuator 25 is controlled as known in the art to achieve an optimal regulation rate of the patient exhalation air through pneumatic air passage 28

Still referring to FIGS. 2 A and 2B, more specific to the inventive principles of the present invention, a leak orifice 30 extends through valve body 21 with a configuration and dimensions to regulate a volume of compressed air within the pneumatic dampening chamber 29. This regulated "leakage" of air acts as a dampening factor that significantly reduces unwanted oscillations of the exhalation valve 10 during operation.

From numerous experimentations persistently conducted by the inventors, the inventors discovered a ratio of an average volume of the compressed air within pneumatic dampening chamber 29 to a diameter of a tubular configuration of leak orifice 30 should be at least 50 and is preferably at least 100 to facilitate an acceptable patient exhalation air regulation without experiencing any significant oscillations of diaphragm 22. More particular, the inventors discovered an optimal ratio of an average volume of 13.9 centimeters³ of the compressed air within pneumatic dampening chamber 29 to a diameter of 0.109 centimeters for the tubular configuration of leak orifice 30.

In practice, leak orifice 30 may extend at any angle into pneumatic dampening chamber 29 including, but not limited to, a perpendicular angle as shown in FIGS. 2 A and 2B. Also in practice, leak orifice 30 may enclose a regulation valve as symbolized by the dashed lines shown in FIGS. 2 A and 2B to thereby vary the compressed air regulation. Examples of a flow valve include, but are not limited to, a check valve and a butterfly valve.

From the description of the exemplary embodiments herein as shown in FIGS. 2A and 2B, those having ordinary skill in the art will appreciate numerous benefits of the present invention including, but not limited to, a prevention of uncontrollable oscillations by an exhalation valve while maintaining desired actuation rates of the diaphragm.

Having described preferred and exemplary embodiments of novel and inventive pneumatically sealed exhalation valve, (which embodiments are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons having ordinary skill in the art in light of the teachings provided herein, including the FIG. 2. It is therefore to be understood that changes can be made in/to the preferred and exemplary embodiments of the present disclosure which are within the scope of the embodiments disclosed herein.

Moreover, it is contemplated that corresponding and/or related systems incorporating and/or implementing the device or such as may be used/implemented in a device in accordance with the present disclosure are also contemplated and considered to be within the scope of the present invention. Further, corresponding and/or related method for manufacturing and/or using a device and/or system in accordance with the present disclosure are also contemplated and considered to be within the scope of the present invention.

Claims

1. A pneumatically exhalation valve (20), comprising:

a valve body (21) enclosing a pneumatic air passage (28) and a pneumatic damping chamber (29) of compressed air;

a diaphragm (22) seated within the valve body (21) isolating the pneumatic damping chamber (29) from the pneumatic air passage (28),

wherein the diaphragm (22) is operable to cyclically regulate a flow of patient exhalation air through the pneumatic air passage (28); and

a leak orifice (30) extending through the valve body (21) into the pneumatic damping chamber (29),

wherein the leak orifice (30) is operable to cyclically regulate a volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) being operated to cyclically regulate the flow of patient exhalation air through the pneumatic air passage (28).

2. The pneumatically exhalation valve (20) of claim 1,

wherein the diaphragm (22) is operable to close the pneumatic air passage (28) to impede the flow of patient exhalation air through the pneumatic air passage (28); and wherein the leak orifice (30) is further operable to increase the volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) closing the pneumatic air passage (28).

3. The pneumatically exhalation valve (20) of claim 1,

wherein the diaphragm (22) is operable to open the pneumatic air passage (28) to facilitate the flow of patient exhalation air through the pneumatic air passage (28); and

wherein the leak orifice (30) is further operable to decrease the volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) opening the pneumatic air passage (28).

4. The pneumatically exhalation valve (20) of claim 1, wherein the leak orifice (30) is configured and dimensioned to impede oscillations of the diaphragm (22) responsive to the diaphragm (22) being operated to cyclically regulate the flow of patient exhalation air through the pneumatic air passage (28).

5. The pneumatically exhalation valve (20) of claim 4,

wherein the leak orifice (30) is further configured and dimensioned to facilitate an operation of the diaphragm (22) cyclically regulating the flow of patient exhalation air through the pneumatic air passage (28) at a specific exhalation rate.

6. The pneumatically exhalation valve (20) of claim 5,

wherein the leak orifice (30) includes a flow valve.

7. The pneumatically exhalation valve (20) of claim 4,

wherein the leak orifice (30) has a tubular configuration.

8. The pneumatically exhalation valve (20) of claim 7,

wherein a ratio of an average volume of the compressed air within the pneumatic damping chamber (29) to a diameter of the tubular configuration of the leak orifice (30) is at least 50.

9. The pneumatically exhalation valve (20) of claim 7,

wherein a ratio of an average volume of the compressed air within the pneumatic damping chamber (29) to a diameter of the tubular configuration of the leak orifice (30) is at least 100.

10. The pneumatically exhalation valve (20) of claim 7,

wherein the average volume of the compressed air within the pneumatic damping chamber (29)is approximately 13.9 centimeters³; and

wherein a diameter of the tubular configuration of the leak orifice (30) is approximately 0.109 centimeters.

11. A method of operating a pneumatically exhalation valve (20) including a valve body (21) enclosing a pneumatic air passage (28) and a pneumatic damping chamber (29) of compressed air, the method comprising:

a diaphragm (22) cyclically regulating a flow of patient exhalation air through the pneumatic air passage (28),

wherein the diaphragm (22) seats within the valve body (21) isolating the pneumatic damping chamber (29) from the pneumatic air passage (28); and

a leak orifice (30) cyclically regulating a volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) cyclically regulating the flow of patient exhalation air through the pneumatic air passage (28), wherein the leak orifice (30) extends through the valve body (21) into the pneumatic damping chamber (29).

12. The method of claim 11,

wherein the diaphragm (22) closes the pneumatic air passage (28) to impede the flow of patient exhalation air through the pneumatic air passage (28); and

wherein the leak orifice (30) increases the volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) closing the pneumatic air passage (28).

13. The method of claim 11,

wherein the diaphragm (22) opens the pneumatic air passage (28) to facilitate the flow of patient exhalation air through the pneumatic air passage (28); and

wherein the leak orifice (30) decreases the volume of the compressed air within the pneumatic damping chamber (29) responsive to the diaphragm (22) opening the pneumatic air passage (28).

14. The method of claim 11,

wherein the leak orifice (30) impedes oscillations of the diaphragm (22) responsive to the diaphragm (22) cyclically regulating the flow of patient exhalation through the pneumatic air passage (28).

15. The method of claim 14,

wherein the leak orifice (30) facilitates an operation of the diaphragm (22) cyclically regulating the flow of patient exhalation air through the pneumatic air passage (28) at a specific exhalation rate.

16 The method of claim 15,

wherein the leak orifice (30) includes a flow valve.

17 The method of claim 14,

wherein the leak orifice (30) has a tubular configuration.

18. The method of claim 17,

19. The method of claim 17,

20. The method of claim 17,