Abstract:
Disclosed herein is a switching valve for transmitting of fluids. In particular, disclosed herein is a switching valve for filling of gas tanks having a housing with an inlet area and an outlet portion. A check valve, a vent valve, and an inlet valve can be disposed within the housing. The vent valve and the inlet valve can be controlled by a slide that is coupled with a pivoting lever which is actuated by a control valve in a pressure controlled manner.

Description:
BACKGROUND 
     1. Field 
     The invention relates to a switching valve for the transmission of fluids, in particular to the filling of gas tanks. 
     2. Description of the Related Art 
     Transmitting systems with such switching valves achieve a safe transmission of a fluid from a pressure source to a gas tank, for example in a fuelling system. Therein the simple operability and safety against contamination is of particular importance. Thus, U.S. Pat. No. 6,769,450 describes a valve system in which possible contamination from back flowing gas is prevented by a check valve such that residual quantities in the valve system are discharged by a vent valve in a controlled manner. 
     Further, WO 98/05898 of the Applicants describes a switching valve in the embodiment of a quick coupling, wherein a housing with a fluid inlet and a fluid outlet as well as several valves are provided in order to ensure a safe seal. These valves are controlled in a certain predetermined order by means of a control lever after connecting the quick coupling, whereby first the outlet valve will be opened, then the collets are closed with further movement of the control lever and finally the inlet valve is opened. Here, the control lever is an eccentric shaft with a sliding sleeve for actuating of the collets engaged with a sealing piston, which also releases the fluid inlet after complete coupling of the quick-connection. Further, a vent valve is provided for enabling pressure equalization before removing the quick-connect coupler even with high pressures without the risk of a backstroke. When closing the valves the exhaust valve works in type of a check valve. Although a safe connection is provided in this way, this coupling still has relative high manufacturing expenditure, in particular by the manual operation via the eccentric shaft. 
     Thus, the object of the invention is to provide a switching valve of the initially mentioned type that has a compact structure and enables simple handling as well as preventing contamination or a fluid reflux by controlled venting. 
     SUMMARY 
     The suggested switching valve with slide is suitable in particular for use in filling of gas tanks, whereby a simple and compact construction results since the switching valve with put-on control valve for pressure controlled operation of a pivoting lever is compact and stably formed in order to be integrated in filling systems in a space-saving manner. 
     The proposed pivoting lever is preferably designed with a leverage, i.e. with different lever lengths, so that a strong operation of the slide is achieved on actuating the valve. The piston of the control valve is preferably connected with the pivoting lever via a bolt, which is particularly arranged at a pivot axis in an intermediate housing. Thus, a sensitive control results, in particular when the piston surface cross sections of the piston are equally formed for the inlet and discharge openings. Further, a simple attachment to the valve housing is achieved, likewise a compact connection with a bypass line for actuating of the pressurized control valve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Subsequently an embodiment is explained and described by the accompanying drawing. Herein: 
         FIG. 1  is a plan view on a switching valve; and 
         FIG. 2  is a side view of the switching valve with integrated inlet valve and vent valve, as well as a put-on control valve in longitudinal half-section. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  show an embodiment of a switching valve  10 . The switching valve  10  has a tubular housing  11  with some housing parts  11   a ,  11   b  and  11   c  bolted to each other, wherein the housing part  11   c  (here right side) serves as inlet area  12  and the left region as outlet portion  13  for forwarding of the fluid to be transferred. The inlet area  12  has an adapter  14 , to which a fluid line  12 ′ for supplying fluid to be transferred can be connected. The connecting adaptor  14  can be adapted to the fluid volume to be transferred, in particular to the desired passage cross sections etc., correspondingly. In the outlet portion  13  a corresponding adapter  14 ′ is provided for the discharge conduit  13 ′. Between the two conduits  12 ′ and  13 ′ a bypass line  15  is intermediate, thus applying the inlet pressure and the output pressure to a control valve  20 , put on the housing  11 , as subsequently explained. 
     The housing part  11   a  encloses a check valve  25  that is represented in  FIG. 2  in a closed position, thus sealing against a valve seat  26  via spring pressure, in order to prevent a reflux from the outlet portion  13 . In the middle housing part  11   b  the check valve  25  is followed to the right by a switching slide  27 , which can axially move (here to the right) along the central axis and shift a sealing disc  24  of a vent valve  35  with this movement. The vent valve  35  and the switching slide  27  are here operated by swiveling of a pivoting lever  50 , being coupled with the switching slide  27 , e.g. by positive engagement via an annular groove  29 . 
     Further, in the right housing part  11   c  an inlet valve  45  with an associated valve seat is disposed towards the inlet range  12 . The inlet valve  45  is likewise shifted by the pivoting lever  50  and the coupling with the switching slide  27  in axial direction, since the switching slide  27  also shifts a valve slide  47  of the inlet valve  45  from the closed position (shown here) into the open position by the movement of the sealing disc  24  of the vent valve  35  towards the right side in type of a sequence control, so that the fluid inflowing from the inlet range  12  can flow through the hollow valve slide  47  and a passage in the sealing disc  24  as well as via the tubular switching slide  27  to the outlet  13 , since check valve  25  is here also pressed into the open position by the filling pressure (of the fuelling system or another pressure source/filling pump). 
     As mentioned above, the housing  11  (including inlet valve  45 , vent valve  35  and check valve  25  inserted therein) bears an intermediate housing  19  onto which the control valve  20  is fitted. In this valve  20  a piston  21  is inserted (and laterally sealed), and urged by a spring  22  to the right position, shown here. The two faces, which are exposed to the respective pressure in the bypass line  15 , preferably possess the same dimension, such that the piston  21  can shift with smallest pressure differences between right (inlet) and left (discharge opening) side in a sensitive way. The response threshold pressure is defined by the spring  22 . The piston  21  is coupled to the pivoting lever  50  by a bolt  53 , so that the control valve  20  can operate the valves  35  and  45  via the slide  27  in a pressure controlled manner. 
     If the pressure in the inlet range  12  (here right side) is higher than on the outlet side  13 , as this is the case on starting and performing a filling operation, then first the piston  21  is moved to the left side here and the slide  27  is moved to the right (by swiveling the pivoting lever  50  in anticlockwise direction). The vent valve  35  is also closed and the inlet valve  45  is pressed into open position. As described above, the fluid then flows through the hollow slide  27 , pushes the check valve  25  into open position and flows to the gas tank (to be filled) via the outlet portion  13 . 
     Then, the pressure on the outlet side becomes larger than the inlet pressure on the end of the filling operation (with filled gas tank or shutdown of the filling pump), such that the piston  21  goes back into the starting position, shown here (right stop), whereby the pivoting lever  50  makes the slide  27  to move again to the left, so that the inlet valve  45  becomes closed, but the vent valve  35  will still be open, in order to bleed out the space between inlet valve  45  and check valve  25 , likewise closed in the meantime (because of the missing inlet pressure). On this swiveling of the pivoting lever  50  (in the clockwise direction) the switching slide  27  is moved to the left, so that the sealing disc  24  of the vent valve  35  releases from its sealing position. Here, the sealing disc  24  and the switching slide  27  as well as the valve slide  47  slightly separate from each other into axial direction, so that the pressure can diminish itself to a pressure balance area  44 , which is formed around the sealing disc  24  as recess-like annular space in a gradation at the housing part  11   c.    
     On opening the vent valve  35  by the switching slide  27 , as described above, pressurized fluid “caught” in the switching valve escapes via the pressure balance area  44  to a bleed bore  43  at the housing part  11   c , in order to flow into a recycling hose or a tank or into the atmosphere, if the fluid is not dangerous. 
     As regards the pivoting lever  50  it is pointed out that the lever prolongations on both sides of the pivot axis  52  are different, e.g. here in the ratio 3:1, so that force leverage is achieved. Thus, a strong operation of the slide  27  and the valves coupled thereto is achieved, even with relative small construction of the control valve  20  (and/or diameter of the piston  21 ). This transmission can be easily changed e.g. by changing the intermediate housing  19  and the pivot axis  52  or extension of the pivoting lever  50  located therein, f. i. for adapting to respective filling pressures. Thus, application of the switching valve  10  with a control valve  20  saddled thereon, is more variable, in particularly when the change, if necessary, is rapidly made by means of screws  60  (cf.  FIG. 1 ). Further, it should be emphasized that the bypass line  15  can also be connected to the adapters  14 ,  14 ′ or directly at the respective inlet/outlet portion  12 ,  13  of the housing  11 , in order to improve the compactness of the pressure controlled valve.