Directional valve and breathing mask with a directional valve

Abstract

A directional valve includes a fixing lug (13), which is arranged eccentrically to a valve membrane (16) and is arranged at a valve housing (15). The dimensions of the fixing lug (13) are selected for fixing the valve membrane (16) relative to the sealing surface (2) of valve seat (1). The size of the eccentric offset (x) is in a range between 8% and 15% of the axis length (D) of the greatest longitudinal extension of valve membrane (16).

Claims

1. A directional valve for a breathing mask, the directional valve comprising: a valve housing with a valve seat; a flexible valve membrane with a circumference, which presets a total area, a circumferential area and a longitudinal axis, said valve seat receiving said flexible valve membrane, said valve seat having an annular essentially flat sealing surface, which surrounds an opening and is sealingly covered by at least partial areas of the circumferential area of said valve membrane during an inspiration phase; and a fixing lug arranged at said valve housing for eccentrically fixing said valve membrane in said valve seat with regard to an axis length of a greatest longitudinal extension of said valve membrane, said fixing lug supporting sealing of said sealing surface by said valve membrane during an inspiration phase, wherein said fixing lug is arranged between a center point of said total area of said valve membrane and an edge of said valve membrane such that an entire said circumferential area of said valve membrane lifts off from said sealing surface during an expiration phase, said fixing lug also being arranged to cause said center point of said total area of said valve membrane to move away from said valve seat during the expiration phase, whereby a flow resistance that is lower compared to a central arrangement of said fixing lug becomes established for an expired gas, said fixing lug being arranged on a side of said membrane diametrically opposite said valve seat, said fixing lug having a Y-shaped cross section.

2. A directional valve in accordance with claim 1, wherein: said fixing lug is arranged offset relative to said center point of said total area in a range between 8% and 25% relative to a dimension of the longitudinal axis of said valve membrane.

3. A directional valve in accordance with claim 1, wherein said fixing lug has a plurality of fixing points, all of said fixing points being eccentrically arranged on said flexible valve membrane.

4. A directional valve in accordance with claim 1, wherein said valve membrane is circular and the longitudinal axis is the diameter of valve membrane.

5. A directional valve in accordance with claim 1, wherein: said flexible valve membrane has a fixed portion arranged eccentrically relative to said valve membrane, all points in said eccentrically fixed portion being eccentrically arranged on said flexible valve membrane, said fixing lug fixing said fixed portion of said valve membrane relative to said valve seat; said flexible valve membrane has a movable portion including all of said valve membrane between said circumference and said fixed portion, and also including all of said valve membrane not included in said eccentrically fixed portion; said valve seat and said fixing lug are dimensioned to be able to move all of said movable portion of said valve membrane away from said valve seat during flow through said opening during the expiration phase.

6. A breathing mask with a directional valve comprising: a valve housing with a valve seat; a flexible valve membrane with a circumference, which presets a total area, a circumferential area, a fixed portion and a longitudinal axis, said valve seat receiving said flexible valve membrane, said valve seat having an annular essentially flat sealing surface, which surrounds an opening and is sealingly covered by at least partial areas of the circumferential area of said valve membrane during an inspiration phase; and a fixing lug arranged at said valve housing for fixing said valve membrane in said valve seat, said fixing lug being arranged on a side of said membrane diametrically opposite said valve seat, said fixing lug eccentrically fixing said fixed portion with regard to an axis length of a greatest longitudinal extension of said valve membrane relative to said valve seat, and for supporting sealing of said sealing surface by said valve membrane during inspiration, all points in said eccentrically fixed portion being eccentrically arranged on said flexible valve membrane, wherein said fixing lug and said fixed portion are arranged between a center point of said total area of said valve membrane and an edge of said valve membrane such that an entire said circumferential area of said valve membrane lifts off from said sealing surface during an expiration phase, and such that all of said valve membrane around said eccentrically fixed portion is able to move away from said valve seat during the expiration phase, a position of said fixed lug is arranged such that a flow resistance that is lower, compared to a flow resistance of a central arrangement of said fixing lug, becomes established for an expired gas, said fixing lug having a Y-shaped cross section in a plane of said flexible valve membrane.

7. A breathing mask with a directional valve in accordance with claim 6, wherein said fixing lug is arranged offset relative to said center of the total area in a range between 8% and 25% relative to a dimension of the longitudinal axis of said valve membrane.

8. A breathing mask with a directional valve in accordance with claim 6, wherein: said center point of said valve membrane is able to move away from said valve seat during flow through said opening during the expiration phase.

9. A breathing mask with a directional valve in accordance with claim 6, wherein said fixing lug has a plurality of fixing points, all of said fixing points being eccentrically arranged on said flexible valve membrane, all points of said flexible valve membrane not fixed by said fixing points being a movable portion; said valve seat and said fixing lug are dimensioned to move all of said movable portion of said valve membrane away from said valve seat during flow through said opening during said expiration phase.

10. A breathing mask with a directional valve in accordance with claim 6, wherein said valve membrane has a circular design and the longitudinal axis is a diameter of said valve membrane.

11. A breathing mask with a directional valve, the breathing mask comprising: a valve housing; a flexible valve membrane having an eccentric fixed portion, all points in said eccentric fixed portion being eccentrically arranged on said flexible valve membrane, said flexible valve membrane defining a movable region, said movable position comprising a centroid of said flexible valve membrane; a valve seat cooperating with said valve membrane and having a flat sealing surface, which surrounds an opening, said valve seat having a lateral edge, which extends upright from said sealing surface and receives said valve membrane; and a fixing lug arranged eccentrically relative to valve membrane and fastened to said valve housing, said fixing lug fixing said fixed portion relative to said valve seat, said fixing lug being dimensioned for fixing the valve membrane against said sealing surface of said valve seat, wherein a size of an eccentric offset of said fixed portion and said fixing lug are selected to be such that said valve membrane lifts off over an entire circumference of said sealing surface during an expiration phase, and such that all of said valve membrane around said eccentric fixed portion, which includes said movable region and said centroid, is able to move away from said valve seat during the expiration phase, said fixing lug having a Y-shaped cross section in a plane of said flexible valve membrane, said fixing lug being arranged on a side of said valve membrane diametrically opposite said valve seat.

12. A breathing mask with a directional valve in accordance with claim 11, wherein: said fixed portion is fixed relative to said valve seat during flow in said one direction; the eccentric offset is in a range between 8% and 15% of a length of a greatest longitudinal extension of said valve membrane.

13. A breathing mask with a directional valve in accordance with claim 11, wherein: a center of said valve membrane is able to move away from said valve seat during flow through said opening during the expiration phase.

14. A breathing mask with a directional valve, the breathing mask comprising: a valve seat having a sealing surface, said valve seat defining an opening; a flexible valve membrane arranged on said valve seat, said flexible valve membrane having a circumference, a fixed portion and a center, said center including a center point of said flexible valve membrane; a fixing lug eccentrically arranged on said valve membrane, said fixing lug fixing said fixed portion of said valve membrane relative to said valve seat, said fixing lug being dimensioned for fixing the valve membrane against said sealing surface of said valve seat during absence of flow through the directional valve, said valve seat and said fixing lug being dimensioned to move said circumference and said center point of said valve membrane away from said valve seat in one direction during flow through said opening in said one direction, wherein a size of an eccentric offset of said fixed portion is selected to be such that said valve membrane lifts off over an entire circumference of said sealing surface during flow in said one direction, said fixing lug having a plurality of fixing points to fix said valve membrane to said fixing lug, said fixing lug being arranged on a side of said valve membrane diametrically opposite said valve seat, said plurality of fixing points of said fixing lug being arranged in Y-shape in a plane parallel to said valve membrane.

15. A breathing mask with a directional valve in accordance with claim 14, wherein: said fixed portion is arranged eccentrically relative to said valve membrane, all points in said fixed portion are eccentrically arranged on said flexible valve membrane; said flexible valve membrane has a movable portion including all of said valve membrane between said circumference and said fixed portion, said movable portion including said center point, said center point being a centroid of said flexible valve membrane; said valve seat and said fixing lug are dimensioned to move all of said movable portion of said valve membrane away from said valve seat during flow through said opening in said one direction.

16. A breathing mask with a directional valve in accordance with claim 14, wherein: said fixed portion is fixed relative to said valve seat during flow in said one direction; said fixing lug is arranged on a side of said membrane diametrically opposite said valve seat; said plurality of fixing points arranging an arching of said valve membrane to bias said valve membrane in contact with said sealing surface, all of said fixing points are eccentrically arranged on said flexible valve membrane, all points of said flexible valve membrane not fixed by said fixing points being a movable portion; said valve seat and said fixing lug are dimensioned to move all of said movable portion of said valve membrane away from said valve seat during flow through said opening in said one direction.

17. A breathing mask with a directional valve in accordance with claim 14, wherein: said fixed portion is fixed relative to said valve seat during flow in said one direction; said eccentric offset is in a range between 8% and 15% of a length of a greatest longitudinal extension of said valve membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view of a valve seat of a directional valve according to the invention;

(2) FIG. 2 is a view of a valve bonnet of the directional valve according to the invention;

(3) FIG. 3 is a longitudinal sectional view of the directional valve; and

(4) FIG. 4 is a graph showing measurement results for the flow resistance R as a function of the gas flow, dV/dt, through the directional valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) Referring to the drawings in particular, FIG. 1 shows a valve seat with a flat sealing surface 2, which surrounds an opening 3 through which the gas flows. Opening 3 is divided by a valve cross 4 into four sectors. An upright edge 5, which receives a valve membrane, not shown in FIG. 1, and centers same against the sealing surface 2, is located around valve surface 2. A centering projection 6 and a circumferential bead 7 are located on the outside of edge 5. The underside 8 of valve seat 1 is connected to a filter mask, not shown in the figure. The webs of valve cross 4 intersect in a center 9.

(6) FIG. 2 illustrates a valve bonnet 10, which is placed on the valve seat 1, FIG. 1, and has for this a centering groove 11, corresponding to centering projection 6, and a circumferential groove 12, corresponding to bead 7. On the inside, valve bonnet 10 has a fixing lug 13, which is directed towards the sealing surface 2.

(7) Valve seat 1 and valve bonnet 10 together form a valve housing 15. The directional valve 20 is formed by the valve housing 15 with the valve membrane 16 inserted. The directional valve 20 is connected as an expiration valve on the underside 8 of valve seat 1 with a filter mask 22. Filter mask 22 and directional valve 20 together form a breathing mask, FIG. 3.

(8) FIG. 3 shows the directional valve 20 in a longitudinal section and a detail of the breathing mask. Identical components are designated by the same reference numbers as in FIGS. 1 and 2. Fixing lug 13 is fastened to the inside of valve bonnet 10 such that an offset x is obtained relative to the center 9. Relative to the diameter D of valve membrane 16, the ratio x/D is in a range of 8% to 15%. The fact that fixing lug 13, and a corresponding fixed portion of valve membrane 16, is positioned in the vicinity of center 9 causes a movable portion of the valve membrane 16 to be lifted off from the sealing surface 2 on both sides of fixing lug 13 during the flow of gas in one direction. The valve membrane 16 on both sides of, or surrounding, the fixing lug 13 being a movable portion of the valve membrane 16. The fixed portion of the valve membrane 16 being that portion of the valve membrane 16 directly contacted by the fixing lug 13, especially as shown in FIGS. 2 and 3. The expired gas enters the environment via outflow openings 14 during the flow in the one direction.

(9) FIG. 4 shows the flow resistance R as a function of the gas flow dV/dt through the directional valve 20. The abscissa shows the gas flow dV/dt in a range of up to 160 L/minute and the ordinate shows the flow resistance R as a static pressure in a range of up to 6 mbar. Curve 24 shows as the first limit value the flow resistance R for a fixing lug 13 positioned in center 9, position “A” in FIG. 3. FIG. 4 illustrates as a second limit value the flow resistance R for a position of the fixing lug at the edge of the sealing surface 2, position “B” in FIG. 3. The middle curve 26 shows the flow resistance R for the arrangement of fixing lug 13 according to the present invention, position “C” in FIG. 3. Even though fixing lug 13 is offset by only 8% in relation to center 9 relative to the diameter D, the flow resistance R increases by only 0.6 mbar at a gas flow of 80 L/minute compared to position “B” of the fixing lug, whereas the flow resistance more than doubles in case of a centrally positioned fixing lug, corresponding to position “A.”

(10) A slight displacement of fixing lug 13 from the center already leads to a marked reduction of flow resistance R.

(11) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

(12) 1 Valve seat 2 Sealing surface 3 Opening 4 Valve cross 5 Upright edge 6 Centering projection 7 Bead 8 Underside 9 Center 10 Valve bonnet 11 Centering groove 12 Circumferential groove 13 Fixing lug 14 Discharge openings 15 Valve housing 16 Valve membrane 20 Directional valve 22 Filter mask 24 Curve A 25 Curve B 26 Curve C