Patent Publication Number: US-8118056-B2

Title: Mixing device with valve disks

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of European application No. 07018752.1 filed Sep. 24, 2007, which is incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The invention relates to a mixing device for mixing substances, especially liquids or gases with different temperatures, with a moveable, adjustable valve control disk and at least one fixed valve seat disk. 
     BACKGROUND OF THE INVENTION 
     With a mixing system, a mixing module, for example, is supplied through two separate circuits in each case with a substance to be mixed. In this way, the mixing module takes a proportion of the different substances to be mixed in order to enable a mixed substance with a required character to be produced. Several valves for distributing and conducting or mixing the various substances are required for this purpose. This makes the mixing system or the mixing module complicated and not cost effective. The control of the mixing system is impractical due to the use of a large number of valves. Furthermore, to protect a mixing module or compensate for the circuits, a mixing path in the mixing system is frequently bridged by one or more bypasses though which a substance to be mixed is passed in each case. The bypass is normally controlled by an extra manual rotary valve and is therefore not variable. 
     A multivalve has also been developed which combines two valves to form a single valve. The multivalve is provided with two fixed bores, each for a bypass. Although this enables the number of valves used to be reduced, a bypass designed in this way is also non-adjustable. It is desirable for a mixing system to have a variable bypass, with the bypass being automatically adjustable as a function of the mixture settings. The greater the flow of a substance for mixing in a mixing path of the mixing system, the less of the substance flows through a bypass and vice versa. Furthermore, more of the substance automatically flows in the mixing path for mixing purposes if less of the other substance, or substances, flows in this mixing path. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to realize a mixing device with a bypass adjustment for mixing substances, especially liquids or gases at various temperatures. 
     The object is achieved in accordance with the invention by a mixing device with the features of the independent claims. The dependent claims relate to advantageous developments and embodiments of the invention. 
     The invention is based on the knowledge that the flow of a substance through an opening can be changed as a function of the size of the cross-section of the opening. Therefore, a mixing device is shown for mixing substances, especially liquids or gases at different temperatures, with a moveable, adjustable valve control disk and at least one fixed valve seat disk, with the valve seat disk having at least two opening groups, each of which consists of at least three through openings. Furthermore, a first opening is provided as an inlet opening or an outlet opening for a substance, a second opening is provided for connecting to a mixing path for the substances and a third opening is provided for bridging the mixing path. The valve control disk is provided on at least one side with a first recess and a second recess. By means of such recesses, a passage for substances between the openings, i.e. between the first, the second and the third opening, of the valve seat disk can be realized for each opening group of the valve seat disk. The valve control disk is arranged parallel to the valve seat disk so that at each opening group a flow is possible, via the first recess, between the first opening and the second opening and via a second recess a flow is possible between the first opening and the third opening. To form a passage, the first and second recesses are, for example, superimposed in each case over the first opening. To control the mixture, the valve control disk is to be adjusted relative to the valve seat disk so that for each group of openings the total superimposed surfaces of the first opening remain constant. In this way, the total surfaces, on which the first recesses are superimposed in each case, of the first openings of the complete group of openings remain constant and the total of the respective surfaces superimposed by the second recesses likewise remain constant. With this mixing device, a variable bypass can be realized in such a way that the passage of a substance in the bypass can be changed as a function of its passage in the mixing path. By adjusting the valve control disk, a passage cross-section, i.e. the superimposed surface of the first opening of the valve seat disk and of the first or second recess of the valve control disk can be changed and the relative proportion of substances to be mixed can thus be controlled. Furthermore, the bypass for the mixing path can be automatically adjusted as a function of the settings of the valve control disk. The valve control disk and the valve seat disk each usually consists of a round disk, with the valve control disk being rotatable relative to the valve seat disk to set the mixing device. It can also be designed in a different shape, e.g. as a rectangle, and the valve control disk can then be pulled or pushed relative to the valve seat disk. 
     According to an advantageous embodiment of the invention, the mixing device consists of a valve control disk and two valve seat disks, with the valve control disk being arranged between, and parallel to, the valve seat disks. The valve control disk is provided on each side with a first recess and a second recess. For each group of openings of the two valve seat disks, the first recess is provided to form a passage between the first opening and the second opening, with the second recess being provided to form a passage between the first opening and the third opening. Two of the second recesses in each case, each of which is arranged on both sides of the valve control disk, are connected to each other by a channel to enable a flow between the two valve seat disks. A mixing device designed in this way can be used on its own in a mixing system to create a mixing path, instead of using the two aforementioned mixing devices, each of which has only one valve seat disk. 
     Advantageously, the two valve seat disks are of identical construction and the first recesses and second recesses can be symmetrically arranged on both sides of the valve control disk. This enables the mixing device to be easily constructed and controlled. 
     According to an advantageous embodiment of the invention, the mixing device has at least two shut-off positions. If the mixing device is set to one of the shut-off positions, the mixing of the substances can be ended or avoided, i.e. the substances no longer flow in the mixing paths but instead they each flow completely in the bypasses. Because at least two shut-off settings are available in the mixing device, it is not necessary to set the mixing device to a specific state in order to separate the mixing of the substances. The mixing can be quickly or easily separated by setting the mixing device to a state corresponding to one of the shut-off positions of this mixing device. 
     In a mixing system, two mixing devices, each of which has only one valve seat disk, can be used to create a mixing path in such a way that a first mixing device can be provided as an inlet (supply valve) and a second mixing valve can be provided as an outlet (return valve), with the second openings of the first mixing device each being connected as an inlet opening and the second openings of the second mixing device each being connected as an outlet opening for a substance. To bridge the mixing path, the third openings of the first mixing device are each connected to the corresponding third openings of the second mixing device. A mixing path and its bypass can in this way be realized by using the two mixing devices. The mixing system can thus be cost effectively constructed because only two mixing devices/valves are used in this case. The substances to be mixed are fed from the second openings of the supply valve into the mixing path and then mixed together. The mixed substances are drawn off via the second openings of the valve seat disk and with the aid of the first recesses of the valve control disk through the first openings of the valve seat disk of the return valve. The substances supplied through the first openings of the supply valve but not fed in for mixing are passed, with the aid of the second recesses in each case, from the third openings of the supply valve through the bypass into the third openings of the return valve and are then passed on via the second recesses of the valve control disk through the first openings of the return valve for bridging the mixing path. 
     Alternatively, a mixing device which has one valve control disk and two valve seat disks can be used in the aforementioned mixing system for the creation of a mixing path. In this case, the mixing device is connected for the creation of a mixing path in such a way that the first valve seat disk is provided as an inlet (supply disk) and the second valve seat disk as an outlet (return disk) of the mixing path. The first openings and the third openings of the supply disk are each connected as the inlet opening for a substance. The second openings of the supply disk are each provided as a substance supply opening of the mixing path, with the second openings of the return disk each being provided as an outlet opening for a mixed substance. The first openings and the third openings of the return disk each also serve as an outlet opening. The mixture path is bridged in that the substances to be mixed are each fed to the third openings of the supply disk and then fed via two second recesses, which are located opposite each other on both sides of the valve control disk and connected by a channel, through the first and/or third openings of the return disk. A mixture path and one or more bypasses can thus be enabled by means of a single mixing device, without a further valve being required. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail in the following with the aid of the exemplary embodiments shown in the diagrams, in which; 
         FIG. 1  shows a mixing system with conventional valves, 
         FIG. 2  shows an inventive mixing device with a valve control disk and a valve seat disk, 
         FIG. 3  shows the different settings of the valve control disk of the mixing device according to  FIG. 2 , 
         FIG. 4  shows an example of the application of the mixing device according to  FIG. 2 , 
         FIG. 5  shows an inventive mixing device with a valve control disk and two valve seat disks, 
         FIG. 6  shows an example of the application of the mixing device according to  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a microreaction system with a reaction module  8 , with the reaction module  8  having a reactor  7  and being supplied via two liquid circles  21 ,  22  which are separately temperature-conditioned. In this process, one liquid circuit  21  is provided for heating and another liquid circuit  22  for cooling. A chemical reaction takes place in the reactor  7 , which is to be carried out at a constant temperature, usually at a high temperature. For this purpose, for example, hot water and cold water are mixed to provide a suitable temperature through a mixing path  13  and then supplied to the reactor  7  in order to guarantee the chemical reaction. Both liquid circuits  21 ,  22  are each supplied from two cryostats  9 ,  10 , each of which conditions the liquid circuit to a constant temperature. The cryostat  9 ,  10  can only output its heating or cooling power if the circuit  21 ,  22  can supply an adequate flow of water. The higher a flow, the more efficient a cryostat. Therefore, the more constant a flow, the more stable the temperature conditioning by a cryostat. 
     At the inlet and outlet of the reaction module  8  are two actuating elements, each of which is based on two valves V 1  and V 2  or V 3  and V 4 . Via valves V 1  and V 2 , the reaction module  8  accepts its share of the hot and cold water supplied to it, in order to achieve a desired temperature by mixing. The mixed water is supplied via the mixing path  13  to the reactor  7  for temperature control of the chemical reaction and is then divided between valves V 3  and V 4  and is in each case returned to the circuits  21 ,  22 . 
     A bridging consisting of a hot bypass B 1  and a cold bypass B 2  is formed for the mixing path  13 . This ensures that the cryostats  9 ,  10  each receive a constant minimum flow. For each bypass, the reaction module  8  has a valve V 5 , V 6 , which is usually a manual rotary valve. Such valves can, however, not be automatically controlled according to a specific relative proportion in which the hot water and cold water are mixed, i.e. the flow of water through the bypass can, for example, only be manually controlled. Therefore, the bypasses B 1 , B 2  are not variable. Even when the valve V 5 , V 6  are each embodied as a multivalve together with the actuating elements V 1 , V 2  and V 3 , V 4 , valves V 5 , V 6  are still realized only once in the form of two fixed bores. Although in this case the number of valves that are used can be reduced, the bypass thus formed is still non-variable. 
     A shown in  FIG. 1 , the reaction module  8  must have six valves V 1 -V 6 . Of these, there are two non-variable valves V 5 , V 6  whose purpose is to ensure the minimum flow to the cryostats  9 ,  10  in advance. The inlet or return flow of the temperature-controlled water can be controlled by valves V 1 , V 4 . Depending on the operating state of the microreactions system, the cryostats  9 ,  10  receive different amounts of flow because the total flow at the cryostats  9 ,  10  varies due to the combination of non-variable bypass flow and variable temperature-conditioned flow. Therefore, the cryostats  9 ,  10  are met with different amounts of water flow of their temperature-conditioned media. In general, however, the cryostats  9 ,  10  should have a flow which is as constant as possible in all operating states. Therefore, the bypasses, B 1 , B 2  must be adjusted during the temperature control so that the total flow at the cryostats  9 ,  10  is constant. 
     Furthermore, due to the many valves, this microreaction system also requires a large number of stepper motors. Associated with this is the danger of the valve settings drifting relative to each other due to step losses in the stepper motors. The number of valves and stepper motors also results in a high space requirement and high costs. 
       FIG. 2  shows a mixing device ( FIG. 2   a ) consisting of a valve control disk  1  ( FIG. 2   c ) and a valve seat disk  2  ( FIG. 2   b ). This mixing device can be constructed from plastic or a ceramic and usually consists of round disks, with the round disks being parallel to each other and being arranged coaxially. When adjusting the mixing device, e.g. for temperature control, the valve control disk  1  is rotated, e.g. mechanically, relative to the valve seat disk  2 . A mixing device of this design can also be easily and readily connected to a water pipe. 
     The valve seat disk  2  has two groups of openings  11 ,  12  each of which is provided for the control and passage of hot water and cold water. Furthermore, each group of openings includes a first opening w 1 , k 1 , a second opening ma, mb for creating a mixing path  13  and a third opening w 2 , k 2  for bridging the mixing path. The valve control disk  1  in  FIG. 2   b  is provided with four trough-shaped recesses on one side only. For the group of openings  11  of the valve seat disk  1 , a first recess wn 1  is provided for forming a passage for hot water between the first opening w 1  and the second opening ma of the valve seat disk  2 , with a second recess wn 2  being provided for forming a passage for hot water between the first opening w 1  and the third opening w 2  of the valve seat disk  2 . Accordingly, a first recess kn 1  is provided for the group of openings  12  of the valve seat disk  1  for forming a passage for cold water between the first opening k 1  and the second opening mb of the valve seat disk  2 , with a second recess kn 2  being provided for forming a passage for cold water between the first opening k 1  and the third opening k 2  of the valve seat disk  2 . If, for example, the first recess wn 1  and the first opening w 1  are set to overlap each other, a hot water flow from the first opening w 1  to the second opening ma is possible. The greater the overlapped surface of the first opening w 1 , the more hot water flows in a time unit through the first recess wn 1  and out from the second opening ma. 
       FIG. 3  shows the various adjustment positions of the valve control disk  1  relative to the valve seat disk  2  of the mixing device shown in  FIG. 2   a . This can be clearly seen in the following table. 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 FIG. 
                 Hot/cold water as 
                   
                   
               
               
                 3 
                 a percentage 
                 Hot circuit 
                 Cold circuit 
               
               
                   
               
             
            
               
                 a) 
                 100/0  
                 100% hot water flows in the 
                 0% cold water flows in the mixing path 13. 
               
               
                   
                   
                 mixing path 13. 
                 100% cold water flows through the bypass 
               
               
                   
                   
                 0% hot water flows through the 
                 section B2. 
               
               
                   
                   
                 bypass section B1. 
               
               
                 b) 
                 75/25 
                 75% hot water flows in the mixing 
                 25% cold water flows in the mixing path 
               
               
                   
                   
                 path 13. 
                 13. 
               
               
                   
                   
                 25% hot water flows through the 
                 75% cold water flows through the bypass 
               
               
                   
                   
                 bypass section B1. 
                 section B2. 
               
               
                 c) 
                 50/50 
                 50% hot water flows in the mixing 
                 50% cold water flows in the mixing path 
               
               
                   
                   
                 path 13. 
                 13. 
               
               
                   
                   
                 50% hot water flows through the 
                 50% cold water flows through the bypass 
               
               
                   
                   
                 bypass section B1. 
                 section B2. 
               
               
                 d) 
                 25/75 
                 25% hot water flows in the mixing 
                 75% cold water flows in the mixing path 
               
               
                   
                   
                 path 13. 
                 13. 
               
               
                   
                   
                 75% hot water flows through the 
                 25% cold water flows through the bypass 
               
               
                   
                   
                 bypass section B1. 
                 section B2. 
               
               
                 e) 
                  0/100 
                 0% hot water flows in the mixing 
                 100% cold water flows in the mixing path 
               
               
                   
                   
                 path 13. 
                 13. 
               
               
                   
                   
                 100% hot water flows through the 
                 0% cold water flows through the bypass 
               
               
                   
                   
                 bypass section B1. 
                 section B2. 
               
               
                 f) 
                 0/0 
                 0% hot water flows in the mixing 
                 0% cold water flows in the mixing path 13. 
               
               
                   
                 shut-off position, 
                 path 13. 
                 100% cold water flows through the bypass 
               
               
                   
                 right hand 
                 100% hot water flows through the 
                 section B2. 
               
               
                   
                   
                 bypass section B1. 
               
               
                 g) 
                 0/0 
                 0% hot water flows in the mixing 
                 0% cold water flows in the mixing path 13. 
               
               
                   
                 shut-off position, 
                 path 13. 
                 100% cold water flows through the bypass 
               
               
                   
                 left hand 
                 100% hot water flows through the 
                 section B2. 
               
               
                   
                   
                 bypass section B1. 
               
               
                   
               
            
           
         
       
     
     It can be seen from this table that by setting the valve control disk  1  the total flow of the hot water flowing in the mixing path  13  and in the bypass B 1  or the total flow of the cold water flowing in the mixing path  13  and in the bypass B 2  always remain constant because the total superimposed surfaces of the first opening w 1 , k 1  of the valve seat disk  2 , which in each case overlap the first recess wn 1 , kn 1  and the second recess wn 2 , kn 2 , remain constant. The superimposed surfaces of the first opening w 1 , k 1  can each be regarded as a passage cross-section for hot water and cold water. The size of the passage cross-section is to be set as the inlet opening for water, so that the hot water and the cold water can be mixed in a suitable proportion. For example, the more hot water flows through the total cross-section, i.e. the superimposed surface of the first recess wn 1  and the first opening w 1  in the mixing path  13 , the less hot water flows through the total cross-section of the second recess wn 2  and of the first opening w 1  in the bypass B 1 . 
     Furthermore, the total amount of surface, which includes the total cross-section of the first recess wn 1  and the first opening w 1  and the total cross-section of the first recess kn 1  and the first opening k 1 , also remains constant. Therefore, more hot water can, for example, automatically and simultaneously flow through the second opening ma for mixing in the mixing path  13  if the cold water flow through the other second opening mb is set smaller. The same applies also for the hot water and the cold water in the bypass sections B 1  and B 2 . 
     Furthermore, there are two shut-off positions (see  FIGS. 3   f  and  3   g ) for this mixing device. At the shut-off positions, the hot water circuit  21  and the cold water circuit  22  are separated. This enables a mixing process to be ended by rotating the valve control disk  1  to one of the two shut-off positions. In both cases, 100% of the hot water flows through the bypass section B 1  and 100% of the cold water flows through the bypass section B 2 . Because a shut-off setting in both directions is possible, it is not necessary to expend energy to rotate the valve control disk  1  back again at the end of a mixing process. 
       FIG. 4  shows an example of an application of a mixing device of this kind in the microreaction system shown in  FIG. 4 . In this case, instead of the six valves in the microreaction system shown in  FIG. 1 , two mixing devices  4 ,  5  are used in such a way that the first mixing device  4  is connected to a mixing path  13  as a supply valve and the second mixing device  5  is connected to the mixing path  13  as a return valve. The valve seat disk  2  of the supply valve  4  is shown in  FIG. 4   a  and the valve seat disk  2  of the return valve  5  is shown in  FIG. 4   b .  FIG. 4   c  is a schematic illustration showing the mixing device in the microreaction system connected to two water circuits  21 ,  22 . Because of the side view of the mixing device in  FIG. 4   c , only the group of openings  11  of the valve seat disks  2 ,  3  and the recesses of the valve control disk  1  for hot water are shown in each case for the supply valve  4  and the return valve  5 . The third openings vw 2 , vk 2  of the supply valve  4  are each connected together as a supply opening of the bypass sections B 1 , B 2  and the third openings rw 2 , rk 2  of the return valve  5  are connected together as an outlet opening of the bypass sections B 1 , B 2 . 
     The hot water and the cold water are supplied to the first openings vw 1 , vw 2  of the supply valve  4  and then flow in each case via the first recesses vwn 1 , vkn 1 , through the second openings rma, rmb in the mixing path  13  on one hand, or via the third openings vw 2 , vk 3  of the supply valve  4  in the bypass section B 1 , B 2  on the other hand. The mixed water is drawn off via the second openings rma, rmb, the first recesses rwn 1 , rkn 1  and the third opening rw 1 , rk 1  of the return valve  5 . Furthermore, the hot water and the cold water each flow through the bypass sections B 1 , B 2  in the third openings and then on through the second recesses rwn 2 , rkn 2  and the first openings rw 1 , rk 1  of the return valve  5 . 
     The combination of two such mixing devices in conjunction with the temperature-conditioning in the micro reaction system clearly shows the advantages of such a mixing device. With these mixing devices, it is possible to mix two separate water circuits and then divide them again into equal proportions. 
       FIG. 5   a  shows a side view of a cross-section of a valve control disk  1 , with this valve control disk  1  being provided with trough-shaped recesses on both sides.  FIG. 5   b  shows the front side VS 1  of this valve control disk  1 , with two first recesses vwn 1 , vkn 1  and two second recesses vwn 2 , vkn 2  being shown.  FIG. 5   b  shows the back RS 1  of this valve control disk  1 , with two first recesses rwn 1 , rkn 1  and two second recesses, rwn 2 , rkn 2  being shown. From this cross-section, it can be seen that in each case two of the second recesses vwn 2  and rwn 2  or vkn 2  and rkn 2 , which are arranged on the front VS 1  ( FIG. 5   b ) and the back RS 1  ( FIG. 5   c ) of the valve control disk  1  respectively, are connected by a channel  6  in order to enable water to pass between the second recesses vwn 2  and rwn 2  or between the second recesses vkn 2  and rkn 2 . The front VS 1  of the valve control disk  1  can be used in the same way as the valve control disk  1  of the supply valve  4  shown in  FIG. 4 . The back RS 1  of the valve control disk  1  can be used corresponding to the valve control disk  1  of the return valve  5  shown in  FIG. 4 . 
     A valve control disk  1  of this kind can be formed from two valve seat disks, which are of similar design to the valve seat disks  2 ,  3  shown in  FIG. 2 , to form a mixing device, with the three valve disks being arranged parallel to each other and pressing against each other with a specific pressure. The valve control disk  1  is arranged in parallel between the two valve seat disks  2 ,  3  and can be rotated relative to the other two valve seat disks  2 ,  3 . The valve seat disks  2 ,  3  are held so that they cannot move. Furthermore, the front of the valve control disk  1  is arranged parallel to the valve seat disk  2  with the back of the said valve control disk  1  being arranged parallel to the valve seat disk  3 . 
       FIG. 6  shows an example of the application of this mixing device in a microreaction system. In this case, this mixing device can be used so that a mixing path  13  for the temperature conditioning of a reactor  7  is created by means of two valve seat disks  2 ,  3 , with, in contrast to  FIG. 4 , it being possible to use the first valve seat disk  2  and the left half of the valve control disk  1  as the supply valve  4  and the second valve seat disk  3  and the right half of the valve control disk  1  as the return valve  5 , i.e. the mixing path  13  and the bypass section B 1 , B 2  can be realized just by means of this mixing device instead of using the two mixing devices in  FIG. 4 . The bypass section B 2  is not shown in the side view of the mixing device in  FIG. 6 . Depending on the positions of the valve control disk  1  relative to both valve seat disks  2 ,  3 , the hot water and the cold water are passed in a specific ratio through the mixing path  13  or the bypass section B 1 , B 2 . 
     The hot water and the cold water in each case are supplied to the first openings vw 1  vk 1  and third openings vw 2 ,vk 2  of the first valve seat disk  2 . The supplied hot water and the supplied cold water in each case flows on one hand via the first recesses vwn 1 , vkn 1  of the valve control disk  1  and out from the second openings vma, vmb of the first valve seat disk  2  into the mixing path  13 , and on the other hand via the second recesses vwn 2 , vkn 2  and the channel  6  in the second recesses rwn 2 , rkn 2  of the valve control disk  1  and then out from the first openings rw 1 , rk 2  and the third openings rw 2 , rk 2  of the second valve seat disk  3  into the circuits  21 ,  22 . 
     The hot water and the cold water are mixed on the mixing path  13 , in order to condition the reactor  7 . The mixed water is in each case supplied through the second openings rma, rmb in the second valve see disk  3  and drawn off via the first recesses rwn 1 , rkn 1  of the valve control disk  1  through the first openings rw 1 , rk 1  of the second valve seat disk  3 . Similar to the mixing device shown in  FIG. 4 , for example, the flow of hot water in the mixing path  13  and in the bypass section B 1  is to be determined depending on the cross-sections, which in each case are formed by the overlap of the first opening vw 1  with the first recess vwn 1  and with the second recess vwn 2 . Accordingly, the flow of cold water in the mixing path  13  and in the bypass section B 2  are to be determined depending on the cross sections, which in each case are formed by the overlap of the first opening vk 1  with the first recess vkn 1  and with the second recess vkn 2 . 
     As shown in  FIG. 3 , there are also two shut-off positions for these mixing devices. If the valve control disk  1  is rotated to one of the two shut-off positions, the mixture of hot water and cold water in the mixing path  13  can be separated by means of this mixing device. In this case, 100% of the hot water flows through the bypass section B 1  and 100% of the cold water through bypass section B 2 . Because there are two shut-off positions for the mixing device, it is not necessary for the separation of the mixture to rotate, sometimes using force, the valve control disk  1  back to a specific shut-off position.