Abstract:
A breathing mask is provided which prevents condensation in the interior space of the mask. The mask body ( 2 ) is provided in some sections with a material ( 8 ) that is waterproof but permeable to water vapor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2009 023 664.3 filed Jun. 3, 2009, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a breathing mask, preferably a breathing mask for medical applications. 
       BACKGROUND OF THE INVENTION 
       [0003]    For respirating (also known as ventilating) a patient, above all for respiration at home, the breathing gas is humidified before it is fed to the patient. Room air is drawn in via a filter and fed to the patient via a humidifier in case of respiration at home, especially for the therapy of sleep apnea. Condensation may now occur in the interior space of the mask, which is perceived by the patient as disturbing if the patient must briefly remove the mask during the night to remove the condensate. Breathing masks that are worn by a patient during sleep are usually used in various positions, corresponding to the individual sleeping habits. High level of sleep comfort must be reached without the patient being disturbed by possible condensation. 
         [0004]    A breathing mask in which a heating coil, which heats the mask to prevent condensation is arranged on the outside of the mask body, is known from JP 2002 052 082 A. The drawback of the prior-art mask is that an additional electric line must be led to the mask for operating the heating coil and that overheating of the mask may occur in case of a defect. 
       SUMMARY OF THE INVENTION 
       [0005]    The basic object of the present invention is to improve a breathing mask of this type such that condensation in the interior space of the mask is avoided. 
         [0006]    According to the invention, a breathing mask is provided comprising a mask body and material connected to the mask body in at least some sections. The material being waterproof but also permeable to water vapor and forming a vapor passageway to remove moisture from the interior space of the mask. 
         [0007]    The material may be connected to the mask body by bonding, pressing or by means of a plug-in frame. The material may be located in openings formed in the mask body. 
         [0008]    The material may be attached on an inside of the mask body. The mask body may have a collection space for condensate between the mask body and the material. 
         [0009]    The material may be a membrane comprising a textile carrier and a barrier layer. Advantageously the textile carrier may consist of polyester and the barrier layer may consist of polyurethane. 
         [0010]    The advantage of the present invention is that moisture is removed from the side of the interior space of the mask facing the patient by means of a material, which is arranged in the area of the mask body and is waterproof, on the one hand, but is permeable to water vapor, on the other hand. Such materials are known from pieces of clothing, where they are used to protect a person from moisture but to make possible the release of body moisture to the environment. 
         [0011]    The material is firmly connected to the mask body either by bonding or pressing or it is arranged detachably on the mask body. In case of connection by bonding, it is possible to connect the material directly with the mask body or to insert it into a groove on the mask body. 
         [0012]    A plug-in frame for the material is suitable for applications in which replacement of the material is desirable. The material is connected for this to the plug-in frame via a plastic wall extending around the outside of the material and the plug-in frame is inserted into a corresponding opening of the mask body. As an alternative, the material can be fastened in a silicone frame, which is arranged on the mask body with separate fastening means, for example, with magnets. 
         [0013]    As an alternative, the material may also be pressed directly into the mask body during the manufacturing process. Openings in the mask body are advantageously suitable for use as fastening points for the material. Either individual, larger openings may be present in the mask body, which are closed with the material, or small perforations are prepared at closely spaced locations from one another in the mask body, which are covered with the material that is in contact on the inside of the mask body. It is also possible as an alternative to press the material directly into the mask body during the manufacturing process, in which case the connection between the inside of the mask and the outside of the mask is established by the openings. 
         [0014]    A suitable material in the form of a membrane is available under the name “Klima-PES-Strickware” [climate control polyester knitwear] and consists of the following components: 
         [0000]                                                textile carrier:   100% polyester,           barrier layer:   100% polyurethane                        
The membrane is resistant to boiling and to disinfectants.
 
         [0015]    The membrane described has a weight of about 115 g/m 2  and a thickness of 0.25 mm. The waterprooofness of the membrane is said to be above 3,000 mm according to DIN EN 20811. The water vapor permeability of the membrane is determined according to DIN 53122 (climate B→38±1° C. and 90±2° relative humidity). The permeability of the membrane is to be related to a period of 24 hours and one square meter of area of the membrane and it thus equals 2,600 g/m 2 d. 
         [0016]    The membrane is absolutely pressure-resistant in the dry state in the case of application, 3-30 mbar. In the wet state, the membrane has a leakage flow of 0.11 L/minute beginning from a respiration pressure of 20 mbar. The leakage flow increases continuously to 0. 26 L/minute with increasing respiration pressure (at 30 mbar). 
         [0017]    The water vapor permeability at a temperature gradient of 12° C. (21° C. under ambient conditions and 33° C. in the interior space of the mask) is approximately 4,240 g/m 2 d. The greater the temperature gradient, the more effectively water vapor is removed from the interior space of the mask to the outside. 
         [0018]    An exemplary embodiment of the present invention is shown in the figures and will be explained in more detail below. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In the drawings: 
           [0020]      FIG. 1  is a side view of a breathing mask; 
           [0021]      FIG. 2  is a top view of the breathing mask according to  FIG. 1 ; 
           [0022]      FIG. 3  is a longitudinal sectional view through an opening in the mask body; 
           [0023]      FIG. 4  is a longitudinal sectional view showing a membrane in a plug-in frame; and 
           [0024]      FIG. 5  is an alternative embodiment of a breathing mask. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    Referring to the drawings in particular,  FIG. 1  shows a side view of a breathing mask  1  according to the present invention. The breathing mask  1  comprises a mask body  2 , a mask pad  3  and a head rest  4 . Breathing gas is sent into the interior space of the breathing mask  1  via an angle piece  5 . The mask body  2  has openings  6 ,  7 , which are closed with a membrane  8 ,  9 , which is waterproof but permeable to water vapor. Corresponding openings closed with membranes, which are not shown in  FIG. 1  for the sake of greater clarity, are likewise provided on the opposite side of the mask body  2 . 
         [0026]      FIG. 2  shows a top view of the breathing mask  1  according to  FIG. 1  with the openings  6 , which are closed with the membranes  8 . The openings  7 ,  FIG. 1 , which are arranged towards the angle piece  5 , are not shown in  FIG. 2  for the sake of greater clarity. 
         [0027]      FIG. 3  shows in detail the longitudinal section of opening  6  with the membrane  8 . Membrane  8  is fastened in an undercut  10  of the mask body  2 . 
         [0028]    In an alternative embodiment according to  FIG. 4 , membrane  8  is received in a plug-in frame  11  and is inserted into the opening  6  by means of the plug-in frame  11 . On a side facing the interior space of the mask, the plug-in frame  11  has two ejectors  12  of a tongue-like design with projections  13 , which are in contact with the inside of the mask body  2 . By compressing the ejectors  12 , the projections  13  are pressed into the opening  6  and the plug-in frame  11  can be removed from the opening  6  to the outside of the mask body  2 . 
         [0029]      FIG. 5  shows a schematic view of an alternative embodiment of a breathing mask  20  with a mask body  21 , with a mask pad  22  and with an angle piece  23 . A membrane  25 , which is fastened, on the one hand, circumferentially to the mask pad  22  as well as to the angle piece  23 , is arranged in the interior space  24  of the mask. A collection space  26  for separated condensate, which can be drained off via a tube connection  27 , is located between the membrane  25  and the mask body  21 . 
         [0030]    While specific embodiments of the invention have been 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 
       [0000]    
       
           1 ,  20  Breathing mask 
           2 ,  21  Mask body 
           3 ,  22  Mask pad 
           4  Head rest 
           5 ,  23  Angle piece 
           6 ,  7  Openings 
           8 ,  9 ,  25  Membrane 
           10  Undercut 
           11  Plug-in frame 
           12  Ejector 
           13  Projection 
           24  Interior space of mask 
           26  Collection space 
           27  Tube connection