Abstract:
A rotary valve for selectively connecting at least one component ( 51, 52 ) into a fluid path. According to the invention the inner stator face ( 111   a,    211   a ) comprises orifices ( 131   b - 136   b;    231   b - 236   b ) and said inner rotor face ( 112   a,    212   a ) comprises at least a first groove ( 121, 221 ), a second groove ( 122, 222 ), and a third groove ( 123, 223 ) so arranged that the rotary valve can take at least three different rotary positions, in which either both components are bypassed, only one of the components is connected and the other bypassed or both components are connected to a main flow.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a filing under 35 U.S.C. §371 and claims priority to international patent application number PCT/SE2008/000317 filed May 8, 2008, published on Nov. 20, 2008, as WO 2008/140377, which claims priority to patent application number 0701220-6 filed in Sweden on May 15, 2007. 
     FIELD OF THE INVENTION 
     The present invention relates to valves and more specifically to rotary valves for selectively enabling components into a main flow. 
     BACKGROUND OF THE INVENTION 
     Valves are commonly used in devices that involve the transportation of a fluid. A typical type of valve, for example used in laboratory systems of moderate sizes, is the rotary valve. 
     Generally, a rotary valve has a stationary body, herein called a stator, which co-operates with a rotating body, herein called a rotor. 
     The stator is provided with a number of inlet and outlet ports. The ports are via bores in fluid communication with a corresponding set of orifices on an inner stator face. The inner stator face is an inner surface of the stator that is in fluid tight contact with an inner rotor face of the rotor. The rotor is typically formed as a disc and the inner rotor face is pressed against the inner stator face in rotating co-operation. The inner rotor face is provided with one or more grooves which interconnect different orifices depending on the rotary position of the rotator with respect to the stator. 
     Rotary valves can be designed to withstand high pressures (such as pressures above 30 MPa). They can be made from a range of materials, such as stainless steel, high performance polymeric materials and ceramics. 
     The number of inlets/outlets as well as the design of grooves in the rotor or the stator reflects the intended use of a specific valve. 
     A common type of multi-purpose valve has one inlet port (typically placed in the rotary axis of the valve) and a number of outlets ports that are placed equidistantly around the inlet port. The rotor has a single, radially extending groove that has one end in the rotary centre, thereby always connecting to the inlet, while the other end connects to any one of the outlets depending on the angular position of the rotor with respect to the stator. Such a valve is useful to direct a flow from the inlet to any of the outlets—one at a time. 
     More complicated arrangements, tailor-made to perform one or several specific tasks, are possible. For instance, rotary valves may be used to introduce a fluid sample into the fluid path of an analytical system. 
     For example, a rotary valve that allows the user to independently of each other control a first flow to either of a set of two outlets, and a second flow to either of a set of another two outlets is described in U.S. Pat. No. 6,672,336 to Nichols. 
     In many instruments handling a flow of a liquid, such as liquid chromatography systems (LCS), there is sometimes a need to be able to either include or to bypass a component. 
     This situation is easily solved with a conventional 4-way double-path valve, schematically shown in  FIGS. 1 and 2 . 
       FIG. 3  shows two components, each connected to a flow path via a conventional 4-way double-path valve. Thus, one or both of the components can be disconnected from the flow. 
     However, it would be beneficial to be able to integrate the possibility to disconnect at least one of two components from the flow path into a single valve. One reason for this would be to save cost (e.g. since there is need for one valve motor drive only in the case of an automatically operated valve). Another reason would be the possibility to shorten path lengths by integrating as much paths into the valve as possible, thereby reducing the need for interconnecting tubing. 
     It would be additionally beneficial if such a valve should include even more functionality, such as the possibility to flush one of the components using a second liquid source. For instance, this would be the case if one of the components requires calibration using a well defined calibration liquid. It would then be useful if this liquid (especially if it is expensive) could be introduced directly (e.g. with a syringe) to the component without the need to have it to pass the entire instrument. 
     Thus, there is a need for a multipurpose valve that allows at least one of two components to be independently connected to/disconnected from a main flow. 
     BRIEF DESCRIPTION OF THE INVENTION 
     This is achieved in a valve according to claim  1  of the present application. 
     Hereby one single rotary valve is achieved which can take at least three different rotary positions, in which either both components are bypassed, only one of the components is connected and the other bypassed or both components are connected to a main flow. This will both give a cheaper valve compared to using two separate valves and minimize interconnecting tubings. 
     Suitable embodiments are described in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows flow through a component using a conventional valve in a first mode. 
         FIG. 2  shows bypassing the component of  FIG. 1  using a conventional valve in a second mode. 
         FIG. 3  shows two components connected to a flow path using two conventional valves. 
         FIG. 4  is a schematic side view of a rotary valve. 
         FIG. 5  is a perspective view of a stator of a first embodiment of the invention. 
         FIG. 6  shows the stator of  FIG. 5  from the inner stator face side. 
         FIG. 7  illustrates the angular distribution of the orifices in the inner stator face of the stator according to  FIG. 5   
         FIG. 8  is a perspective view of a rotor of the first embodiment of the invention. 
         FIG. 9  illustrates the angular distribution of the grooves of the inner rotor face of the rotor according to  FIG. 8 . 
         FIG. 10  is a schematic view of the first embodiment of the invention in a first position. 
         FIG. 11  is a schematic view of the first embodiment of the invention in a second position. 
         FIG. 12  is a schematic view of the first embodiment of the invention in a third position. 
         FIG. 13  is a schematic view of the first embodiment of the invention in a fourth position. 
         FIG. 14  is a schematic view of the inner stator face of a second embodiment of the invention. 
         FIG. 15  is a schematic view of the inner rotor face of the second embodiment of the invention. 
         FIG. 16  is a schematic view of the second embodiment of the invention in a first position. 
         FIG. 17  is a schematic view of the second embodiment of the invention in a second position. 
         FIG. 18  is a schematic view of the second embodiment of the invention in a third position. 
         FIG. 19  is a schematic view of the second embodiment of the invention in a fourth position. 
         FIG. 20  is a schematic view of the second embodiment of the invention in a fifth position. 
         FIG. 21  is a schematic view of a modification of the second embodiment of the invention in a fifth position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The main parts of a typical rotary valve are schematically shown in  FIG. 4  (wherein no brackets or similar load carrying or fastening elements are shown). The rotary valve  10  has a stator  11 , a rotor  12 , a rotary shaft  13  that optionally may be provided with means (not shown) for recognizing its angular position and a driving unit  14  typically comprising a gear box and a motor (although a valve also may be operated manually). The rotor is rotatable with respect to the stator around a rotary axis RA of the valve. 
     The stator  11 , which is fixed with respect to the instrument into which it is built, is provided with ports (not shown in  FIG. 4 ) for fluid communication with a fluid source and any components with which the valve is to co-operate. The ports may be positioned on any suitable part of the stator, and in any suitable direction. The ports are provided with means to connect capillaries or tubing. Such means may be of any suitable type, such as conventional Valco fittings well known to anyone skilled in the art. The ports are via channels in fluid communication with a corresponding set of orifices on an inner stator face  11   a , i.e. that surface of the stator that during operation is in contact with the rotor  12 . 
     The rotor  12  is typically formed as a disc and has an inner rotor face  12   a  that is that face that is pressed against the inner stator face  11   a  during operation. The inner rotor face  12   a  is provided with one or more grooves which interconnect different orifices of the inner stator face  11   a  depending on the rotary position of the rotor with respect to the stator. 
       FIG. 5 , which shows a simplified perspective view of the front side of a stator  111 , illustrates the inlet and outlet port arrangement for a first embodiment of a valve according to the present invention. 
     Generally, it should be noticed that the angular position of ports, grooves and similar shown in the figures of the present application could differ between different embodiments of the invention, i.e. they could be turned with respect to the rotary axis of the valve, mirrored or altered in other ways as long as their mutual co-operation is still according to the inventive idea. 
     In addition, since the inlet/outlet ports are connected to orifices on the inner stator face  11   a  via bores (or any type of channels) it is possible to arrange the ports in a way that differs from the pattern on the inner stator face  11   a  by making non-linear channels between the ports and the orifices. However, for reasons of simplicity, the ports are shown as being positioned in-line with the inner stator face orifices, as will be described below in relation to  FIG. 6 . 
     Thus, the stator  111  of a first embodiment according to the present invention has seven ports  131   a - 137   a  that are used to connect the valve to all desired operative components of the instrument. 
     A first port  131   a  is a central port used as inlet port from a first liquid source of the instrument, such as a pump, typically via a set of components of the instrument such as detectors, other valves etc., and any connected components such as a chromatography column. A second port  132   a  serves as an outlet port from which the liquid is allowed to exit to the remaining part of the instrument or out from the instrument. 
     A first component, such as a conductivity monitor or a flow restrictor device, is connectable to the valve via a third port  133   a  and a fourth port  134   a , whereby the third port  133   a  acts as an outlet from the valve and the fourth port  134   a  as an inlet to the valve for the returning flow. 
     A second component, such as a pH monitoring sensor, is connectable to the valve via a fifth port  135   a  and a sixth port  136   a  whereby the fifth port  135   a  acts as an outlet from the valve and the sixth port  136   a  as an inlet to the valve for the returning flow. 
     A seventh port  137   a  is an inlet that allows a second fluid source (such as a syringe) to be connected. This is, for instance, useful as a means for manual flushing of the second component, as is shown below. It should be noted that the seventh port  137   a  is optional, i.e. it could be omitted if the flushing feature is not of interest. 
       FIG. 6  is a perspective view of the stator  111  of  FIG. 5  viewed from the other side, i.e. the inner stator face side  111   a . Note that each port is connected to the inner stator face  111   a  via a channel ending in a corresponding orifice, a first orifice  131   b , a second orifice  132   b , a third orifice  133   b , a fourth orifice  134   b , a fifth orifice  135   b , a sixth orifice  136   b  and optionally a seventh orifice  137   b  shown in  FIG. 6 . 
     In addition to the orifices connected to the ports, a stator groove  138  is provided in the inner stator face  111   a . The groove is typically of essentially the same width as an orifice diameter. The orifice third  133   b  is situated inside the stator groove  138 . 
     Looking at the inner stator face  111   a , the general angular distribution of the orifices and the groove ends is illustrated in  FIG. 7 . The positions for orifices, groove ends (and not used positions) are equally distributed around the center of the stator (which center coincides with the rotary axis of the valve). As described above the positions of the orifices can be varied slightly without departing from the inventive idea. Since there are twelve such positions on the stator according to the embodiment, the partition angle α is 30°. All these positions are placed with essentially the same radial distance R to the rotational axis of the valve. 
     The inner rotor face  112   a  of a rotor  112  of a first embodiment of the invention for cooperation with the stator  111  above is shown in  FIG. 8 . It is provided with five grooves, called the first, second, third, fourth and fifth groove  121 - 125 , respectively. However, the fourth and fifth grooves  124 ,  125  are optional and not necessary for the invention as will be further described below. The mutual positions and shapes of the grooves are more clearly illustrated in  FIG. 9 . 
     Each rotor groove has both its ends ending essentially at the same radial distance R from the center, except for one end of the first groove  121  that ends in the center of the inner rotor face  112   a  (coinciding with the rotary axis of the valve). Of course, the radial distance R for the rotor is the same as the corresponding radial distance R of the stator. The first groove  121  is a straight groove from the center of the rotor face out towards the rim, with a length of R, and is parted from the nearest end of the second groove  122  by the angle  2 α. The second groove  122 , that extends over an angle of  3 α, is bent inwards toward the centre to form a knee (or alternatively in an arcuate shape), thereby giving place for the third groove  123  that extends the angle α tangentially. The fourth and fifth grooves  124  and  125  each extend over an angle α. The angle α is in the present embodiment 30°. The fourth and fifth grooves  124  and  125  are mutually separated by the angle α. The fourth groove  124  is separated from the second groove  122 , also with the angle α. 
     When assembled, the inner rotor face  112   a  is pressed against the inner stator face  111   a  in a manner that is typical for any conventional rotary valve (which is well known for anyone skilled in the art, and will not be explained herein). Depending on the mutual angular positions of the rotor  112  and the stator  111  different operation modes are obtained for the valve. These are illustrated in  FIG. 10-13 , wherein the grooves of the rotor are indicated by thick lines. 
     In the first rotary position of the rotor of the first valve embodiment, as shown in  FIG. 10 , the valve is useful to bypass both a first component  51  and a second component  52 . The flow enters the first port  131   a , goes via the first orifice  131   b  through the first rotor groove  121  and exits the valve through the second port  132   a  (via the second orifice  132   b ). 
     The other ports and grooves of the valve are not active in the first rotary position, i.e. both the first and the second components  51 ,  52  are bypassed. 
     The second rotary position, as shown in  FIG. 11 , is obtained by rotating the rotor an angle of  4 α clockwise (as seen from the view of  FIG. 11 ) with respect to the first rotary position. The second position is useful to bypass the second component  52 . 
     In the second rotary position the fluid that enters the first port  131   a  and the first orifice  131   b  will pass through the first rotor groove  121  and then the stator groove  138  to exit to the first component  51  via the third orifice  133   b  and the third port  133   a . After passing the first component  51 , the flow returns to the valve via the fourth port  134 , passes the third rotor groove  123  and then exits the valve via the second port  132 . 
     The other ports and grooves of the valve are not active in the second rotary position, i.e. the second component  52  is bypassed. 
     The third rotary position, as shown in  FIG. 12 , is obtained by rotating the rotor an angle of α counterclockwise (as seen from the view of  FIG. 12 ) with respect to the second rotary position. In this position, the flow passes both the first and the second components  51 ,  52 . 
     In the third rotary position, the fluid enters the first port  131   a  and the first orifice  131   b  and passes through the first groove  121  to exit to the first component  51  via the third orifice  133   b  and the third port  133   a . In this case, the stator groove  138  forms a short cul-de-sac that can be rinsed when the rotor is set to the second rotary position. After passing the first component  51 , the flow returns to the valve via the fourth port  134   a  and the fourth orifice  134   b , passes the second rotor groove  122  and then exits to the second components  52  via the fifth orifice  135   b  and the fifth port  135   a . After having passed the second component  52 , the flow returns to the valve via the sixth port  136   a  and the sixth orifice  136   b , passes the third groove  123  and then exits the valve via the second orifice  132   b  and the second port  132   a.    
     The other ports and grooves of the valve are not active in the third rotary position. 
     The fourth rotary position, as shown in  FIG. 13 , is obtained by rotating the rotor an angle  2 α clockwise (as seen from the view of  FIG. 13 ) with respect to the second rotary position. This position, that is optional, is useful for manual rinsing of the second component  52  (such as during a calibration procedure for the second component  52  or for cleaning purpose). 
     In the fourth rotary position, a fluid is entered via the seventh port  137   a  and the seventh orifice  137   b , for example by using a syringe connected to the port. The fluid passes the fifth rotor groove  125  to exit to the second component  52  via the fifth orifice  135   b  and the fifth port  135   a . After having passed the second component  52 , the flow returns to the valve via the sixth port  136   a  and the sixth orifice  136   b , passes the third groove  123  and then exits the valve via the second orifice  132   b  and the second port  132   a.    
     The other ports and grooves of the valve are not active in the fourth rotary position, i.e. the first component  51  is bypassed. 
     It should be noted that in this fourth position, without an additional outlet orifice the first rotor groove  121  forms a stop for any flow from the fluid source via the first orifice  131   b . In a modification of the first valve embodiment, an additional outlet orifice  139   b  (and corresponding additional outlet port) could be provided at a position corresponding to the outer end of the first groove  121  in this forth position to provide an outlet for the flow from said fluid source. The additional outlet orifice  139   b  is shown in  FIG. 13 . However this additional orifice is optional and not necessary for the invention. 
     Thus, with a valve of the first embodiment it is possible to selectively bypass the valve, connect the first component  51  in-line while bypassing the second component  52 , or connect the first and second components  51 ,  52  (in said order) in-line. In addition an optional flushing position in provided. 
     A rotor  212  and stator  211  design of a second embodiment of a valve according to the present invention are shown in  FIGS. 14 and 15 . 
     An inner stator face  211   a  of a stator  211  of the second embodiment is shown in  FIG. 14 . The shown orifices  231   b - 237   b  are in communication with connecting ports (not shown for this embodiment) in the same way as is described above for the first embodiment. 
     The inner stator face  211   a  of the stator  211  is similar to the inner stator face  111   a  of the first embodiment in that it is provided with a first orifice  231   b  that is a central inlet, a second orifice  232   b  that is an outlet, a third orifice  233   b  that is an outlet to a first component and a fourth orifice  234   b  that is an inlet from said first component, a fifth orifice  235   b  that is an outlet to a second component and a sixth orifice  236   b  that is an inlet from said second component, an optional seventh orifice  237   b  that is an inlet for flushing purpose and an essentially tangential stator groove  238  extending over an angel α corresponding to the partition angel of the valve, all (except the first orifice  231   b ) being at a radial distance R from the stator face centre. However, it differs from the first embodiment in that the fifth and seventh orifices  235   b  and  237   b  are rotated the angle α counterclockwise (when viewing the inner stator face) with respect to their positions in the first embodiment. 
     The inner rotor face  212   a  of the rotor  212  of the second embodiment for cooperation with the stator  211  above is shown in  FIG. 15 . It is provided with a first groove  221 , a second groove  222 , a third groove  223  and a fourth groove  224 . 
     As for the first embodiment, all rotor grooves end at essentially the same radial distance R from the center, except for one end of the first groove  221  that ends in the center of the rotor face  212   a  (coinciding with the rotary axis of the valve). The radial distance R for the rotor is the same as the corresponding radial distance R of the stator. The third and the fourth grooves  223  and  224  each extend over the angle α, which in the present embodiment is 30°. The first groove  221  is a straight groove from the center of the rotor face out towards the rim, with a length of R, and is parted from the nearest end of the second groove  222  by the angle  2 α. The second groove  222 , that extends over an angle of  4 α, is bent inwards toward the centre to form a knee (or alternatively in an arcuate shape), thereby giving place for the third groove  223  that extends the angle α tangentially, starting from a position at an angle of  3 α counterclockwise from the outer end of the first groove  221  when viewing the rotor face. The fourth groove  224  extends the angle α tangentially, starting from a position at an angle of  2 α clockwise from the outer end of the first groove  221  when viewing the inner rotor face. 
     Similar to the first embodiment, different operational positions are obtainable when the stator and rotor faces are mated in rotational cooperation. These are shown in  FIG. 16-20 . 
     In the first rotary position of the rotor of the second valve embodiment, as shown in  FIG. 16 , the valve is useful to bypass both the first and the second component  51 ,  52 . The flow enters the inlet port and goes via the first orifice  231   b  through the first rotor groove  221  and exits the valve through the outlet port via the second orifice  232   b.    
     The second rotary position, as shown in  FIG. 17 , is obtained by rotating the rotor an angle of  4 α clockwise (as seen from the view of  FIG. 17 ) with respect to the first rotary position. The second position is useful to bypass the second component. 
     In the second rotary position the fluid that enters the inlet port and the first orifice  231   b  will pass through the first groove  221  and then the stator groove  238  to exit to the first component  51  via the third orifice  233   b . After passing the first component  51 , the flow returns to the valve via the fourth orifice  234   b , passes the third rotor groove  223  and then exits the valve via the port connected with the second orifice  232   b.    
     The third rotary position, as shown in  FIG. 18 , is obtained by rotating the rotor an angle of  3 α clockwise (as seen from the view of  FIG. 18 ) with respect to the first rotary position. In this position, the flow may pass both the first and the second components  51 ,  52 . 
     In the third rotary position, the fluid enters via the first orifice  231   b  to pass through the first groove  221  and then exits to the first component  51  via the port connected with third orifice  233   b . In this case, the stator groove  238  forms a short cul-de-sac that can be rinsed when the rotor is set to the second position, or to the fifth rotary position described below. After having passed the first component  51 , the flow returns to the valve via the port connected with the fourth orifice  234   b , passes the second groove  222  and then exits to the second component  52  via the port connected with the fifth orifice  235   b . After passing the second component  52 , the flow returns to the valve via the port connected with the sixth orifice  236   b , passes the third rotor groove  223  and then exits the valve via the outlet port connected with the second orifice  232   b.    
     A fourth rotary position, as shown in  FIG. 19 , is obtained by rotating the rotor an angle of  3 α counterclockwise (as seen from the view of  FIG. 19 ) with respect to the first rotary position. The fourth position is useful to bypass the first component. 
     In the fourth rotary position, the fluid enters via the first orifice  231   b  and passes through the first groove  221  to exit to the second component  52  via the port connected with the fifth orifice  235   b . After passing the second component  52 , the flow returns to the valve via the sixth orifice  236   b , passes the fourth rotor groove  224  and then exits the valve via the outlet port connected with the second orifice  232   b.    
     A fifth rotary position, as shown in  FIG. 20 , is obtained by rotating the rotor an angle  2 α counterclockwise (as seen from the view of  FIG. 20 ) with respect to the first rotary position. This position, that is optional, is useful for manual flushing of the first component  51  (such as during a calibration procedure for the first component  51  or for cleaning purpose). 
     In the fifth rotary position, a fluid is entered via the port in communication with the seventh orifice  237   b , for example by using a syringe connected to the port. The fluid passes the second rotor groove  222  and the stator groove  238  to exit to the first component  51  via the port connected with the third orifice  233   b . After having passed the first component  51 , the flow returns to the valve via the port in communication with the fourth orifice  234   b , passes the fourth rotor groove  224  and then exits the valve via the outlet port connected with the second orifice  232   b.    
     Thus, with a valve of the second embodiment it is possible to selectively bypass the valve, connect the first component  51  in-line while bypassing the second component  52 , connect the second component  52  in-line while bypassing the first component  51 , or connect the first and second components  51  and  52  (in said order) in-line. In addition an optional flushing position is provided. This means that the second embodiment adds the possibility to connect the second component  52  in-line while bypassing the first component  51 , as compared to the first embodiment described above. 
     It should be noted that in this fifth position, without an additional outlet orifice, the first rotor groove  221  forms a stop for any flow from the fluid source via the first orifice  231   b . This might be a disadvantage in a case where the user desires to use the fluid source also when the valve is in this fifth position. Therefore, in a modification of the second embodiment illustrated in  FIG. 21 , an additional outlet orifice  239   b  is provided between the fifth and sixth orifices  235   b ,  236   b  associated with the second component  52 . 
     The modification consists of the addition of an additional outlet port in the stator, said port is in fluid communication with the additional outlet orifice  239   b  of the inner stator face. The additional outlet orifice  239   b  is situated between the fifth and sixth orifices  235   b  and  236   b  in such a way that it connects to the first rotor groove  221  when the rotor is in its fifth position, as described above. Thus, any flow entering the valve via the port associated with the first orifice  231   b  will pass the first groove  221  and then exit the valve via the additional outlet orifice  239   b.    
     One specifically advantageous application of the invention is when a pH-sensor is the component that can be flushed, i.e. the second component in the first embodiment and the first component in the second embodiment. The feature of flushing the pH-sensor gives the advantage that the pH-sensor can be calibrated and stored in a storage solution without having to be demounted from its holder. 
     It should be noted that the fourth groove of both the first and second embodiment and the fifth groove of the first embodiment are optional and not necessary for the invention. However these grooves add additional suitable features to the invention as previously described. 
     As described above the exact position of the orifices need not to be according to the embodiment described above. What is important for the invention is that the different grooves reaches the specific orifices that should be reached in each rotation position described above. 
     It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.