Abstract:
A device for releasing breathing gas establishes constant flow conditions for the breathing gas being discharged. An annular connection element ( 6 ) is provided between an outer part ( 2 ) and an inner part ( 4 ), and a discharge gap ( 7 ) is formed between the connection element ( 6 ) and the outer part ( 2 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2007 052 898.3 filed Nov. 7, 2007, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention pertains to a device for releasing breathing gas. 
     BACKGROUND OF THE INVENTION 
     A device of the type is known from DE 198 40 760 A1 (corresponding to U.S. Pat. No. 6,112,745). Such devices are used in conjunction with so-called CPAP respirators (Continuous Positive Airway Pressure), with which a constant airway pressure, which assists the spontaneous breathing, is set for the patient, e.g., in connection with the treatment of sleep apnea. 
     The prior-art device comprises an outer part and an inner part, which are rotatable in relation to one another and are fitted together by means of a snap-in connection. The external diameter of the inner part and the internal diameter of the outer part are selected to be such that an annular gap is formed, through which the breathing gas can flow off into the environment from the inner area. The two free ends of the prior-art device are connected to a breathing mask, on the one hand, and to a flexible breathing tube, on the other hand, and the torsional moments possibly developing at the flexible breathing tube can be extensively eliminated due to the rotatability of the outer part in relation to the inner part. 
     The diameters of the outer part and of the inner part, which form the annular gap, must be exactly coordinated with one another in order for a sufficiently high pressure to be able to be built up in the flexible breathing tube, on the one hand, and for flow noises due to the breathing gas flowing out of the annular gap to be reduced to a minimum, on the other hand. The width of the annular gap changes due to manufacturing tolerances, and it is also not possible to prevent the inner part from being in contact with the outer part on one side, as a result of which an asymmetrical annular gap becomes established, which has an adverse effect on the pressure conditions and the flow noises. 
     SUMMARY OF THE INVENTION 
     The basic object of the present invention is to improve a device of the type such that constant flow conditions will become established for the breathing gas being discharged from the annular gap. 
     According to the invention, a device is provided for releasing breathing gas. The device is provided with an outer part, with an inner part, which has a cylindrical sliding surface, and with an annular connection element, which has a mounting sleeve, which is designed corresponding to the cylindrical sliding surface of the inner part. The mounting sleeve is located on the inside. A stop is provided for fixing the inner part. A discharge gap is formed between the connection element and the outer part. 
     The advantage of the device according to the present invention is that an annular connection element is additionally provided, which forms a constant discharge gap together with the outer part, on the one hand, and has a mounting sleeve for the inner part, on the other hand. Due to the inner part being fastened by means of the mounting sleeve, the rotary motion of the inner part is uncoupled in relation to the outer part. Due to the connection element, there are no reactions when the inner part is being moved in relation to the outer part, and the geometry of the discharge gap remains unchanged. 
     The outer contour of the connection element can be designed in respect to the inner contour of the outer part such that optimal flow conditions will become established while the lowest possible noise is generated. The length and width of the discharge gap can now be selected to be such that acceptable flow values will become established. 
     A reproducible gap width of the discharge gap can be advantageously embodied by means of spacing elements arranged on the circumference of the connection element. 
     The connection element has, in addition to the mounting sleeve, a stop for the sliding surface of the inner part. 
     It is especially advantageous to fix the connection element such that it is secured against rotation in relation to the outer part by the spacing elements having snap-in pins, which snap into groove-like depressions on the outer part. The means securing against rotation can now be embodied such that the spacing elements are pushed into grooves belonging to them on the outer part, as a result of which a preferential position of the connection element is obtained in relation to the outer part. However, it is also possible, as an alternative, to achieve the securing against rotation solely by the frictional engagement of the snap-in pins within the groove-like depressions. Another possibility of securing against rotation is to bond or weld the connection element to the outer part. 
     An improvement of the centering of the inner part in relation to the outer part is obtained by means of a guide element, which is connected to the inner part and which is inserted into a contact surface designed correspondingly thereto on the outer part. The guide element adjoins the sliding surface of the inner part via the webs. The guide element in conjunction with the contact surface as well as the sliding surface in conjunction with the stop form together an axial guide of the inner part in relation to the outer part. 
     An exemplary embodiment of the present invention is shown in the drawings 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 a preferred embodiment of the invention is illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a side view showing a device according to the present invention for releasing breathing gas; 
         FIG. 2  is a sectional view showing the device according to  FIG. 1  in a longitudinal section; 
         FIG. 3  is a side view showing an outer part; 
         FIG. 4  is a longitudinal sectional view showing the outer part according to  FIG. 3 ; 
         FIG. 5  is detail A according to  FIG. 4 ; 
         FIG. 6  is a side view showing an inner part; 
         FIG. 7  is a longitudinal sectional view showing the inner part according to  FIG. 6 ; 
         FIG. 8  is a side view showing a section connection element; and 
         FIG. 9  is a longitudinal sectional view showing the connection element according to  FIG. 8 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings in particular,  FIG. 1  schematically shows a side view of a device  1  according to the present invention for releasing breathing gas, containing an outer part  2  with a mask port  3  and an inner part  4  with a flexible tube port  5 . 
       FIG. 2  shows the device  1  according to  FIG. 1  in a longitudinal section. Identical components are designated by the same reference numbers as in  FIG. 1 . The inner part  4  is fastened rotatably by means of a connection element  6  within the outer part  2 . An annular discharge gap  7  for breathing gas is formed between the connection element  6  and the outer part  2 . 
     The inner part  4  has a cylindrical sliding surface  8 , which is located within a mounting sleeve  9  having a design corresponding thereto with a stop  10 . The sliding surface  8  is adjoined via webs  11  by a disk-shaped guide segment  12 , which is in contact with a contact surface  13  of the outer part  2 . The contact surface  13  and the stop  10  limit the axial clearance of the inner part  4  in relation to the outer part  2 . 
       FIG. 3  illustrates a side view of the outer part  2 . The mask port  3  is designed such that it comprises a 22-mm outer cone and a 15-mm inner cone arranged therein, as can be determined from  FIG. 4 .  FIG. 4  shows a longitudinal section through the outer part  2 . The mask port  3  with the external diameter of 22 mm expands stepwise to a discharge section  14  with an external diameter of 36 mm. On its inner surface  15 , the discharge section  14  has axially extending grooves  16 , which are provided with locking grooves  18  towards the front side  17 . 
       FIG. 5  shows an enlarged view of detail A according to  FIG. 4  in the area of groove  16  and the locking groove  18 . 
       FIG. 6  shows a side view of the inner part  4 . The inner part  4  is shown in a longitudinal section in  FIG. 7 . The sliding surface  8  has a shoulder  19 , which is in contact with the stop  10  of connection element  6 . 
       FIG. 8  shows a side view of the connection element  6 . Axially extending, bar-shaped spacing elements  21 , which extend axially, are designed corresponding to the grooves  16  of the outer part  2 ,  FIG. 4 , and have snap-in pins  22  directed towards the front side  17 , are arranged on the outer side  20  of the connection element  6 . 
       FIG. 9  illustrates a longitudinal section of the connection element  6  according to  FIG. 8 . An opening  23  for inserting the inner part  2  is located in the area of stop  10 . 
     To mount the device according to the present invention, the inner part  4  is at first inserted into the connection element  6  such that the sliding surface  8  is located within the mounting sleeve  9  and the stop  10  strikes the shoulder  19 . The inner part  4  is then inserted together with the connection element  6  into the outer part  2  such that the spacing elements  21  are located within the grooves  16 . When the snap-in pins  22  have snapped into the locking grooves  18 , the inner part  4  is nondetachably connected to the outer part  2  and the discharge gap  7  is formed between the connection element  6  and the outer part  2 . 
     While a specific embodiment of the invention has 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.