Abstract:
A clamp valve is provided. A clamp valve or a squeeze valve may be straight-way valves, which include a tubular shut-off element, which is sometimes arranged in a tubular housing made of metal or plastic. The tubular shut-off element is either squeezed together mechanically or by an externally supplied foreign medium until the closed position is achieved. In one embodiment, a squeeze valve includes a first flexible tubular segment, the cross-section of which can be influenced by a first tube squeezing apparatus and a second flexible tubular segment, the cross-section of which can be changed by a second tube squeezing apparatus. The tube squeezing apparatuses may be controlled such that an opening process of the second tubular segment is executed at the same time as a closing process of the second tubular segment.

Description:
[0001]    The present patent document claims the benefit of German Patent Application DE 10 2008 026 851.8 filed on Jun. 5, 2008, which is hereby incorporated by reference. 
       BACKGROUND 
       [0002]    The present embodiments relate to squeeze valves. 
         [0003]    Squeeze valves are straight-way valves, which include a tubular shut-off element. The shut-off element is arranged in a tubular housing made of metal or plastic. The tubular shut-off element is either squeezed together mechanically or by an externally supplied foreign medium until the closed position is achieved. A squeeze valve may be referred to as a clamp valve. 
         [0004]    Squeeze valves are primarily used as shut-off instruments for liquid media or solids. Different tubular sleeve designs render the squeeze valves suitable for controlling very different media. As a result, squeeze valves are used in various fields, for instance, in the food processing industry and the chemical industry as well as in medical engineering. During an infusion using a drip, the dosing of the drip speed is performed by a roller clamp that operates as a squeeze valve in conjunction with a flexible tube. 
         [0005]      FIG. 1  shows a known mechanical squeeze valve  10 .  FIG. 1A  indicates the completely opened state and  FIG. 1B  indicates the completely closed state. Squeeze valve  10  includes a flexible tube  11  between a punching tool  13  and a thrust bearing  12 . Squeeze valve  10  is actuated by punching tool  13  being moved in the direction of the thrust bearing  12  (shown by arrow  16 ), with the tube  11  located therebetween being pressed together accordingly and the tube diameter which is effective in terms of transporting a medium  14  reducing. An arrow  15  in  FIG. 1A  shows the transport direction of the medium. 
         [0006]      FIG. 2  shows a known squeeze valve  20  which is actuated by a foreign media.  FIG. 2A  indicates the completely opened state and  FIG. 2B  indicates the completely closed state. Squeeze valve  20  includes a flexible tube segment  21 , which is surrounded by a pressure tank  22  which is filled with the foreign medium  23 . Squeeze valve  20  is actuated by the pressure in the foreign medium  23  being increased (indicated by arrow  26 ), with the flexible tube part  12  inside the pressure tank  22  being pressed together accordingly and the tube diameter which is effective in terms of transporting a medium  23  reducing. An arrow  25  in  FIG. 2A  shows the transport direction of the medium. 
         [0007]    A change in pressure or volume flow develops along the tube when closing the known squeeze valves  10 ,  20 . The change in pressure or volume flow is indicated in  FIG. 1B  by arrows  17  and in  FIG. 2B  by arrows  27 . The volume flow corresponds to the squeezed tube volume and spreads in both directions from the valve  10 ,  20  in the tube. The ratios when opening the valve  10 ,  20  are correspondingly inverse. 
         [0008]    This behavior is problematic, particularly the flow occurring in the discharge line, when small quantities of the medium  14 ,  24  are to be dosed or refluxes have to be prevented. If two-component adhesives are to be mixed in a dosing chamber, for example, the reflux of the hardening agent into the line can block the line since already mixed adhesive reaches the line. In a medical application, the dosing of a medicine could change if the valve is closed or blood could enter the catheter when opening the valve, and could be changed there by contact with a concentrated medicine and result in complications in the case of a subsequent injection. 
       SUMMARY AND DESCRIPTION 
       [0009]    The present embodiments may obviate one or more of the problems or drawbacks inherent in the related art. For example, in one embodiment, a squeeze valve may prevent the volume flow in the tube at least in one direction. 
         [0010]    In one embodiment, a squeeze valve may include a first flexible tubular segment and a second flexible tubular segment. The cross-section of the first flexible tubular segment can be influenced by a first tube squeezing apparatus. The cross-section of the second flexible tubular segment can be changed by a second tube squeezing apparatus. The tube squeezing apparatuses being controlled such that an opening process of the second tubular segment is executed at the same time as a closing process of the first tubular segment and vice versa. 
         [0011]    The change in volume at the second tubular segment may correspond to at least approximately half of the change in volume at the first tubular segment. 
         [0012]    The squeeze valve may include an equalization apparatus in the form of a second flexible tubular segment with a second tube squeezing apparatus. Accordingly, it is possible to avoid an outwardly effective change in volume on one side of the valve when opening and/or closing the valve, since the change in volume acting in the direction and caused by the first tube squeezing apparatus forming the valve in the narrower sense is compensated by a suitable countermovement of the compensating device. 
         [0013]    A squeeze valve may include an equalization apparatus on both sides. It is thus irrelevant how the actuation of the valve is effected and how the coupling of the tube squeezing apparatuses takes place. Mechanical, hydraulic, or pneumatic actuations and the same couplings in any combination are conceivable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]      FIG. 1  shows a known mechanical squeeze valve; 
           [0015]      FIG. 2  shows another known squeeze valve; 
           [0016]      FIG. 3  shows a first exemplary embodiment of a squeeze valve with mechanical control of the tube squeezing apparatuses; 
           [0017]      FIG. 4  shows a second exemplary embodiment of a squeeze valve with a mechanical control of the tube squeezing apparatuses; and 
           [0018]      FIG. 5  shows a third exemplary embodiment of a squeeze valve with a hydraulic control of the tube squeezing apparatuses. 
       
    
    
     DETAILED DESCRIPTION  
       [0019]    A first exemplary embodiment of a squeeze valve  30  is shown in  FIG. 3 .  FIG. 3A  indicates the completely opened state and  FIG. 3B  indicates the completely closed state. Squeeze valve  30  includes a tube  31  with three flexible tubular segments  31 A,  31 B and  31 C and associated tube squeezing apparatuses  33 A,  33 B and  33 C. Alternatively, the tubular part  31  may be equally as flexible, thereby simplifying the design. 
         [0020]    Segment  31 A is a tubular segment which is used for flow regulation. The tubular segments  31 B and  31 C are used to equalize the change in volume brought about by opening or closing segment  31 A. 
         [0021]    The primary punching tool  33 A on segment  31 A is coupled to two secondary punching tools  33 B,  33 C by two levers  38 A,  38 B, which are rotatably mounted in points  39 A,  39 B. In the opened valve state ( FIG. 3A ), the two secondary punching tools  33 B,  33 C compress the respective tubular segments  31 B,  31 C to such a degree that the volume of the medium  34  which is displaced thereby corresponds at least approximately to the half of the volume of the medium  24 , which is displaced by the assigned tubular segment  31 A in the case of a complete closure of the primary punching tool  33 A ( FIG. 3B ). 
         [0022]    The geometry and arrangement of the moveable parts, such as the punching tool  33 A-C, lever  38 A, B and the respective lever arms, may be selected such that the change in volume produced by the movement of the primary punching tool  33 A in the squeezing area  31 A is at least approximately twice as large as the change in volume in the squeezing areas  31 B, C brought about by the opposite movement of the secondary punching tool  33 B, C. 
         [0023]    During operation of the valve  30 , a change in volume may be brought about by the movement of the primary punching tool  33 A to be compensated for on both sides by the movement of the secondary punching tool  33 B,  33 C. Pressure and/or volume outside the valve do not change as a result of actuating the primary punching tool  33 A. 
         [0024]    The squeeze valve  30  may include a one-sided equalization apparatus, for example, if only one side (inflow or outflow) of the valve is sensitive to change in volumes. The other equalization punching tool and the corresponding lever may be left out. 
         [0025]    The coupling of the three punching tools  33 A-C takes place mechanically in the exemplary embodiment in  FIG. 3 , but can however also take place hydraulically or electromechanically or by an electronic controller with corresponding electrically controlled punching tools  33 A-C. 
         [0026]    The quantity which has already flowed may not be changed by wear of the tube. This is important with medication dosing, for example. Medium (possibly contaminated) is not drawn back in and the flow direction remains constant. There are no overpressures in the inflow, so that dosing pumps used there are not influenced by repercussive pressures. The squeezing profile may be designed in an almost wear-free and flexible fashion. No particularly small squeezing cross-section needs to be provided in order to keep the change in volume small, since any size of change in volumes can in principle be compensated. The correspondingly lower mechanical loads allow (cheaper) tubular materials to be used. 
         [0027]    A thrust bearing may be attached if opposite to the punching tool  33 A-C. Instead of punching tools, pincer-like squeezing apparatuses can be used. The pincer-like squeezing apparatuses may constrict the tube on two sides. Surrounding squeezing apparatuses may be used. The surrounding squeezing apparatuses may be operated electromechanically and may surround and constrict the whole periphery of the tube. 
         [0028]    The apparatus may be dimensioned such that a subpressure takes effect (contrary to the overpressure developing in the case of conventional squeeze valves) on the inflow and outflow (not shown) when the primary punching tool  33 A is closed. Only the volume displaced by the secondary punching tool  33 B, C in the opened valve state has to be greater than the half of the volume which can be displaced by the primary punching tool. 
         [0029]    Other tube geometries may be equipped with squeeze valves, for example, different tubular diameters on the inflow and outflow. Accordingly, only the secondary punching tools may have to be suitably adjusted. 
         [0030]    A tube geometry is shown in  FIG. 4 .  FIG. 4A  shows a top view of the valve  40 .  FIG. 4B  shows a section along the line A-A with a completely opened valve  40 .  FIG. 4   c  shows a section along the line A-A with a completely closed valve  40 . 
         [0031]    The tube  41  of the valve  40  is arranged in a u-shape. Arrows  45 A and  45 B show the flow direction of the medium  44  through the tube  41 . The primary tube squeezing apparatus  43 A acts on a flexible tubular segment  41 A, which is located in the summit of the “U” formed by the tube  41 . The second tube squeezing apparatuses (e.g., only the tube squeezing apparatus  43 C of the inflow can be seen in the sectional representation) act on flexible tubular segments  41 B and  41 C, which are found in the arms of the “U”. 
         [0032]    In one exemplary embodiment, the tube squeezing apparatuses are coupled to a rocker  48 , which is rotatably mounted in an axis  49 . One arm of the rocker  48  supports the primary tube squeezing apparatus  43 A, the other arm is T-shaped and supports the two secondary tube squeezing apparatuses. 
         [0033]    The two secondary tube squeezing apparatuses compress the respective tubular segments  41 B,  41 C in the opened valve state ( FIG. 4B ) to such a degree that media volumes displaced as a result corresponds at least approximately to half of the media volumes displaced by the assigned tubular segment  41 A when the primary tube squeezing apparatus  43 A ( FIG. 4C ) is closed. 
         [0034]    The geometry and arrangement of the moveable parts, such as the tube squeezing apparatuses  43 A-C, rocker  48  and the respective rocker arms, may be selected such that the change in volume produced by the movement of the primary squeezing apparatus  43 A in the squeezing area  41 A is at least approximately twice as large as the opposite movement of the secondary squeezing apparatuses in each instance. 
         [0035]    The modifications described in conjunction with  FIG. 3  may be used in the exemplary embodiment of  FIG. 4 . To avoid repetitions, reference is made to the corresponding text passages of the description of figures relating to  FIG. 3 . 
         [0036]      FIG. 5  shows a hydraulically operated squeeze valve  50 . A line  51  has three flexible segments  51 A-C, with the average segment  51 A fulfilling the actual valve function and segments  51 B and  51 C being used for the pressure/volume equalization. The flexible segments  51 A-C may be surrounded in each instance by pressure tanks  52 A-C, which are filled with foreign medium  53 . Squeeze valve  50  is closed by the pressure in the primary tank  52 A being increased, with the flexible tubular part  51 A within the pressure tank  52 A being pressed together accordingly and in this way reducing the tubular diameter which is effective in respect of transporting a medium  54 . 
         [0037]    The pressure in the secondary pressure tanks  52 B and  52 C is reduced at the same time so that tubular parts  51 B and  51 C arranged within this pressure tank extend. The valve apparatus  50  is constructed such that the volume released by tubular parts  51 B and  51 C corresponds here to at least approximately half of the volume displaced by the tubular part  51 A. 
         [0038]    Contrary to the mechanical valves  30  and  40  known from  FIG. 3  and  FIG. 4 , no pre-stress need be applied to the equalization sites in the opened valve state in the hydraulic valve  50  according to  FIG. 5 . Instead, the equalization can be effected by generating a subpressure in the secondary pressure tanks  52 B and  52 C. 
         [0039]    A suitable coupling of the pressure tanks allows the volume released by the tubular parts  51 B and  51 C to correspond here at least approximately to half of the volume displaced by the tubular part  51 A. 
         [0040]    One possible coupling is shown in  FIG. 5 . A common cylinder  58  filled with foreign medium has two boreholes. The first borehole feeds the primary tank  52 A by a supply line  60 A. A second borehole, with which two supply lines  60 B and  60 C are connected, feeds the secondary tanks  52 B and  52 C. A piston  59  is arranged between the boreholes. Moving the piston  59  in the direction of arrow  56  results in the desired drop in pressure in the primary container  52 A and at the same time in the drop in pressure in the secondary containers  52 B and  52 C. The same quantity of foreign medium is pushed into the primary container  52 A as is removed from the two secondary containers  52 B and  52 C, for example, half of the volume pressed into the primary container  52 A is removed from each of the secondary containers  52 B and  52 C. As a result, the tubular part  51 A is compressed by the volume, while the tubular parts  51 B and  51 C expand by half of this volume in each instance. 
         [0041]    This also applies to the embodiment according to  FIG. 5 , such that pressure and/or volume outside the valve do not change as a result of actuating the valve. Various embodiments described herein can be used alone or in combination with one another. The forgoing detailed description has described only a few of the many possible implementations of the present invention. For this reason, this detailed description is intended by way of illustration, and not by way of limitation. It is only the following claims, including all equivalents that are intended to define the scope of this invention.