Abstract:
A diaphragm valve is provided, in which there is improved sealing of a closing cover ( 15 ) against the valve housing ( 3 ). The seal includes a cylindrical sealing washer ( 25 ), which is connected to the valve housing ( 3 ) in one piece and into which a cylindrical wall section ( 18 ) of the closing cover ( 15 ) can be inserted with press fit.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of priority under 35 U.S.C. § 119 of German Application DE 10 2004 049 151.8 filed Oct. 7, 2004, the entire contents of which are incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The present invention pertains to a controllable diaphragm valve for a respirator/ventilator.  
       BACKGROUND OF THE INVENTION  
       [0003]     A diaphragm valve of the type mentioned, i.e., for a respirator/ventilator (breathing equipment), has become known from DE 33 41 711 C2. A valve chamber and a control chamber, which are separated from one another by means of a diaphragm, are located in a valve housing with a gas feed line and a gas outlet line. The gas feed line leads to a valve seat, which is closed by the diaphragm or is released depending on the pressure in the control chamber. The valve housing has an essentially cylindrical design, and a closing cover, which is sealed against the valve housing by means of an O-ring, is located at the end of the control chamber.  
         [0004]     The drawback of the prior-art diaphragm valve is that a separate sealing ring, which makes assembly difficult, is needed to seal the closing cover against the valve housing.  
       SUMMARY OF THE INVENTION  
       [0005]     The basic object of the present invention is to provide a diaphragm valve that has a better sealing of the closing cover against or relative to the valve housing.  
         [0006]     According to the invention, a diaphragm valve for a respirator is provided with a gas feed line, which leads in a valve housing into a valve chamber and ends in a valve seat. A gas outlet line leads out of the valve chamber. A valve body spans over the valve chamber. With the valve body the valve seat can be closed and the flow of gas from the gas feed line into the gas outlet line can be interrupted. With the valve body a control chamber is formed within the valve housing, separated from the valve chamber. A closing cover closes a cylindrical control chamber end of the valve housing. A cylindrical, flexible sealing washer is connected with the valve housing in one piece. The cylindrical, flexible sealing washer is provided at the control chamber end. A cylindrical wall section of the closing cover is designed as a wall section that can be inserted into the sealing washer with a press fit.  
         [0007]     The advantage of the diaphragm valve according to the present invention is essentially that a cylindrical circumferential joint, which is connected with the valve housing in one piece, and into which a cylindrical wall section of the closing cover is inserted with press fit, is provided at the outwardly directed end of the control chamber. Both the valve housing and the circumferential joint consist of an elastomer material, so that the circumferential joint can be injection molded directly on the valve housing. The wall thickness of the circumferential joint is selected to be such that it is slightly stretched during the insertion of the closing cover and is sealingly in contact with the cylindrical wall section of the closing cover as a result.  
         [0008]     The closing cover is advantageously fastened to the valve housing by means of a snap-in connection. Locking cams located on the inside are provided for this purpose at a cover mount of the valve housing, and a locking ring, which slides over the locking cams when the closing cover is inserted into the valve housing and then snaps in, is located at the end of the closing cover. At the same time, the cylindrical wall section of the closing cover engages the circumferential joint.  
         [0009]     The length of the circumferential joint is advantageously in a range of 2.5 mm to 3.5 mm, the wall thickness is 0.8 mm to 1.2 mm, and the internal diameter of the circumferential joint has a value between 43 mm and 45 mm. Preferred dimensions are a length of 3 mm, a wall thickness of 1.2 mm and an internal diameter of 44 mm.  
         [0010]     A lead-in bevel for the closing cover with an opening angle of 120° or an angle of 60° in relation to the horizontal is provided at the front end of the circumferential joint. Damage to the circumferential joint during the insertion of the closing cover is prevented from occurring by the lead-in bevel.  
         [0011]     The valve housing consists of polypropylene and the closing cover of polyethylene. This material combination of the valve housing and the closing cover has proved to be particularly advantageous, because polyethylene is somewhat softer than polypropylene and the closing cover can therefore adapt well to the circumferential joint.  
         [0012]     An exemplary embodiment of the present invention is shown in the figure and will be explained in greater 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  
       [0013]     In the drawings:  
         [0014]      FIG. 1  is an exploded view of the diaphragm valve according to the present invention; and  
         [0015]      FIG. 2  is a longitudinal sectional view through detail A according to  FIG. 1 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Referring to the drawings in particular,  FIG. 1  illustrates the diaphragm valve  1  according to the present invention in an exploded view. A gas feed line  2  at a valve housing  3  extends over a valve seat  4  to a gas outlet line  5 . As a result, a valve chamber  6  is formed within the valve housing  3 . A valve body  7  of the diaphragm valve  1  comprises a diaphragm element  8 , a valve support  9  and a sealing washer  10 . The sealing washer  10  is buttoned into a groove  11  of the valve support  9  and lies flush on a sealing surface  12 . A disk-shaped fastening element  13  at the valve support  9  is held in a recess  14  of the diaphragm element  8 . A closing cover  15  for the valve housing  3  is of a cylindrical design and has a ring mount  16  for the diaphragm element  8 , a control chamber section  17 , a cylindrical wall section  18 , and a locking ring  19 .  
         [0017]     The diaphragm element  8  has an annular gap  20 , so that the ring mount  16  can be pushed into the gap  20  and the underside of the diaphragm element  8  lies flush on the shoulder  21  of the closing cover.  
         [0018]     A diaphragm support  22 , a control chamber wall  23  with a control pressure connection  24 , a circumferential joint  25 , and a cover mount  26  with a locking cam  27  are provided in the valve housing  3  in the area of the diaphragm element  8 . The cover mount  26  adjoins the control chamber wall  23 , and the circumferential joint  25  is injection molded directly on the end  31  of the control chamber wall  23 .  
         [0019]     With the closing cover  15  inserted into the valve housing  3 , the diaphragm element  8  is located within the diaphragm support  22 . The control chamber section  17  and the control chamber wall  23  of the valve housing  3  together form an annular gap, which is the control chamber  28  for the diaphragm element  8 . The control pressure, by which the valve support  9  with the sealing washer  10  is pressed against the valve seat  4 , is admitted into the control chamber  28  via the control pressure connection  24 . The valve chamber  6  is separated by the valve body  7  with the diaphragm element  8  from the control chamber  28 .  
         [0020]     Before the closing cover  15  is inserted into the valve housing  3 , the valve body  7  is first placed on the ring mount  16 , so that the valve body  7  is fixed against the closing cover  15 . Then, the locking ring  19  will first touch the underside of the locking cams  27 . Pressure exerted on the rear side of the closing cover  15  causes the cover mount  26  to expand somewhat, and the locking ring  19  slides over the locking cams  27  and then snaps in. The cylindrical wall section  18  is in contact with the sealing washer  25  in the locked state of the closing cover  15 , so that the control chamber  28  is sealed against the environment. The closing cover  15  can be removed from the cover mount  26  only by destroying it, so that reuse of the diaphragm valve  1  after disassembly is no longer possible. The diaphragm valve  1  according to the present invention is preferably used as a disposable article.  
         [0021]      FIG. 2  illustrates the detail A according to  FIG. 1  in a longitudinal section along the axis of symmetry  30 . Identical components are designated by the same reference numbers as in  FIG. 1 .  
         [0022]     At the front end, the circumferential joint  25  has a lead-in bevel  29 , which forms an angle of 60° with the horizontal. Damage to the circumferential joint  25  during the insertion of the wall section  18 ,  FIG. 1 , is prevented by the lead-in bevel  29  from occurring.  
         [0023]     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.