Abstract:
The invention relates to a device for measuring and/or detecting the internal pressure of lumens or flexible tubes. The inventive device has a cage which surrounds the outer wall of the lumen or the tube, and at least one sensor for measuring the force exerted on said cage by the internal pressure.

Description:
BACKGROUND OF THE INVENTION 
     For measuring the interior pressure of hoses or lumen, pressure sensors that directly impinged with or submitted to the interior pressure are known. The disadvantage of this prior art is that the medium being transported through the respective lumen or hose comes into direct contact with parts of the sensor and that the channel formed by the hose must be opened in order to connect the sensor. 
     The object of the invention is to present a new device that enables the simplified measuring of pressure without opening the hose or lumen. 
     SUMMARY OF THE INVENTION 
     Measuring interior pressure is to be understood according to invention among other things as the measuring with production of an analog or digital variable signal dependent on the pressure, but among other things also verification and monitoring of the interior pressure, of changes in pressure and/or of the upper and/or lower deviation from pressure values (threshold values). 
     The measuring and/or determination and/or acquisition of the interior pressure or of the pressure change in a hose or lumen occurs by measuring and/or acquisition of the force which the interior pressure exerts on the retainer or cage surrounding the hose. The hose or lumen is enclosed in this retainer in such a way that a deformation or change in shape of the lumen or hose or of the wall of these does not occur. For this purpose the retainer is preferably formed or adjusted in such a way that he wall of the hose or lumen is supported by the retainer for example without deformation, i.e. also especially without interior tensile stress that would stretch the material in the case of a lumen or hose with no pressure or with a low interior pressure, but also with the highest expected pressure. 
     The inherent elasticity of the material of the hose or lumen is insignificant for the invention, so that measuring and/or determination and/or acquisition of the interior pressure is also possible with hoses made of inflexible material, for example with an elastic-viscous hose material. Especially also changes in the elasticity of the respective hose, for example through aging etc. have no effect on the measuring result. 
    
    
     BRIEF DESCRIPTION OP THE INVENTION 
     Examples of the invention are now described in more detail in connection with the Figures, which illustrate: 
     FIG. 1 in a very simplified depiction, a cross section of a hose as well as of a first embodiment of the device according to invention 
     FIG. 2 a similar depiction as in FIG. 1, however in a second possible embodiment of the invention 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the figures, a lumen or a hose  1  is impinged with interior pressure P or with the pressure of a medium located within, or flowing through, the hose. The device illustrated in FIG. 1 serves to measure the interior pressure P or the pressure change ΔP. It consists of two saucer-type or grooved bearing elements  2 ,  3 , which hold the hose  1  between them and form an almost completely inflexible retainer surrounding the hose. The two bearing elements  2 ,  3  are symmetrically arranged with a vertical middle plane M. Bearing element  2  is directly connected to a fixed thrust bearing  4 . Bearing element  3  is supported on its opposite side on the hose  1  by a thrust bearing  7  over an adjusting element  5  and a force sensor  6 . The bearing elements  2 ,  3  form a circular cylindrical arched concave bearing surface  2 ′ or  3 ′, respectively, for the external surface of the hose  1 . With the adjusting element  5 , which enables an axial adjustment perpendicular to the plane of the thrust bearing  7 , the bearing element  3  can be advanced so that it fits with its circular arc concave bearing surface  3 ′ flat and tightly against the outer wall of the non-stretched hose  1 . 
     If the interior of the hose  1  is impinged with the pressure P or if a change in the pressure P occurs, this pressure change ΔP will be converted by the power sensor  6  into an electrical signal. The magnitude or value of the signal is a measure of the pressure P or the pressure change ΔP. The power sensor  6  is preferably a sensor that already delivers a measuring signal for minimal mechanical changes, for example a sensor based on the piezo effect, a sensor with a variable electrical resistance dependent on the pressure, with a variable capacity dependent on the measured pressure or power, an optoelectrical sensor and so on. Also, a switch that changes over from a first state into a second state when the pressure P or the pressure change ΔP exceeds a pre-defined threshold value is suitable as a power sensor. 
     The device shown in FIG. 2 differs from the device in FIG. 1 principally in that the two thrust bearings  4  and  7  are formed by the flanks  4   a  and  7   a  of a U-shaped or bow-shaped frame  8 . In addition to the flanks  4   a  and  7   a  the frame has, a yoke  9  connecting the two flanks. The flank  4   a  is coupled to the yoke  9  (joint  10 ) and can be swiveled on an axis parallel to the axis of hose  1  toward the outside, for the purpose of inserting and removing the hose  1  into or from the space between the bearing elements  2  and  3 . By means of a locking device not shown the joint  10  can be locked and/or the two free ends of the flanks  4   a  and  7   a  can be connected to each other, so that a closed, fixed frame  8  is attained. With the outer surface of flank  7   a  and yoke  9 , the frame  8  fits onto an elbow support or bracket  11  to which it is suitably fastened. Bracket  11  is part of a device or device support etc. not further depicted. 
     The devices described here are suitable for measuring and/or monitoring and/or determination and/or acquisition of the interior pressure of hoses or other lumen that convey a fluid, gaseous or vaporous medium. For example, for measuring and/or acquisition, and monitoring the interior hose pressure in or of medical equipment, but of other equipment as well. Especially the pressure of aggressive or poisonous media can also be measured and/or acquired with the devices. Furthermore, the measuring of blood pressure of blood vessels that are not open is possible. A special advantage lies in the fact that the measurement and/or acquisition of pressure can occur with no great risk with sterile systems, since a measuring head that is directly in contact with the interior of the respective lumen or hose  1  is not necessary. 
     The adjustment of the two bearing elements  2  and  3  relative to each other occurs in such as way that the bearing elements  2  and  3  for example fit tightly against the hose when not under pressure. The hose  1  between the bearing elements  2  and  3  is possibly even slightly pressed together so that upon impingement of the hose  1  with the interior pressure P the resulting force from the interior pressure P on the power sensor can be measured, without deformation or stretching of the wall of the section of hose located between the bearing elements  2  and  3 . 
     If the flow resistance for the fluid, gaseous or vaporous medium flowing through hose  1  is known, then the flow volume can be determined from the measured pressure P. 
     The invention was described above using examples. Of course, numerous alterations and modifications are possible without abandoning the object of invention upon which the invention is based. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 List of Reference Marks 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 1 
                 hose/lumen 
               
               
                   
                 2, 3 
                 bearing element 
               
               
                   
                 4 
                 thrust bearing 
               
               
                   
                 4a 
                 flank or shank 
               
               
                   
                 5 
                 adjusting element 
               
               
                   
                 6 
                 power sensor 
               
               
                   
                 7 
                 thrust bearing 
               
               
                   
                 7a 
                 flank or shank 
               
               
                   
                 8 
                 frame 
               
               
                   
                 9 
                 yoke 
               
               
                   
                 10 
                 joint 
               
               
                   
                 11 
                 bracket