Ultrasound detectable instrument

Abstract

An ultrasound detectable instrument ( 10 ) includes bubble generating means comprising two elements ( 32 a , 32 b ) which, upon contact with each other in the presence of a fluid, react with each other to produce gas bubbles which may be detected by sonic imaging equipment. The two elements comprise first and second radially displaced layers of said elements within a fluid permeable carrier material.

1 . An instrument insertable into a medium and being capable of detection by sonic imaging equipment comprises: 
 an elongate member, for insertion into said medium and having a region the position of which it is desirable to monitor;    bubble generating means, generating a plurality of discrete mobile bubbles at said region, whereby said bubbles are detectable by sonic imaging equipment, characterised in that;    said bubble generating means comprises two elements which, upon contact with each other in the presence of a fluid, react with each other to produce said gas bubbles and in which said elements comprise first and second radially displaced layers of said elements within a fluid permeable carrier material.    
     
     
         2 . An instrument as claimed in  claim 1  and further including a fluid permeable intermediate layer between said two element containing layers.  
     
     
         3 . An instrument as claimed in  claim 1  or  claim 2  and further including a foundation layer on said instrument upon which are deposited said element containing layers.  
     
     
         4 . An instrument as claimed in  claim 3  in which said foundation layer comprises a fluid permeable layer.  
     
     
         5 . An instrument as claimed in any one of  claims 1  to  4  and including a primer layer on said instrument upon which said fluid permeable carrier material is deposited.  
     
     
         6 . An instrument as claimed in any one of claims  4  or  5  and including a primer layer on said instrument upon which said fluid permeable foundation layer is situated.  
     
     
         7 . An instrument as claimed in any one of  claims 1  to  6  in which said carrier material comprises a hydrophilic material.  
     
     
         8 . An instrument as claimed in any one of  claims 1  to  7  in which said carrier material comprises Hydrothane™.  
     
     
         9 . An instrument as claimed in any one of  claims 1  to  8  in which said two elements comprise citric acid and sodium hydrogen carbonate.  
     
     
         10 . An instrument as claimed in  claim 9  in which the citric acid comprises dissolved citric acid.  
     
     
         11 . An instrument as claimed in any one of the preceding claims in which said first layer comprises a radially inner layer and comprises citric acid and said second layer comprises a radially outer layer and comprises sodium hydrogen carbonate.  
     
     
         12 . An instrument as claimed in any one of  claims 1  to  10  in which said first layer comprises a radially inner layer and comprises sodium hydrogen carbonate and said second layer comprises a radially outer layer and comprises citric acid.  
     
     
         13 . An instrument as claimed in any one of  claims 2  to  12  in which said intermediate layer comprises a hydrophilic material.  
     
     
         14 . An instrument as claimed in  claim 13  in which said hydrophilic material comprises Hydrothane™.  
     
     
         15 . An instrument as claimed in any one of  claims 1  to  14  in which said elongate member includes a prepared surface prepared by solvent degreasing or wet blasting.  
     
     
         16 . An instrument as claimed in  claim 15  when having a wet blasted surface.  
     
     
         17 . An instrument as claimed in any one of  claims 5  to  16  in which said primer layer comprises an acid etched layer.  
     
     
         18 . An instrument as claimed in any one of  claims 5  to  16  in which said primer layer comprises a chromate free water based primer (Cytec BR6752) or Chronoflex™ AL80A.  
     
     
         19 . An instrument as claimed in any one of  claims 1  to  18  in which the ratio of bubble generating means to carry material in said first or said second layer is between 20% and 200% by weight.  
     
     
         20 . An instrument as claimed in any one of  claims 1  to  19  in which the ratio of the first to the second reactive agents is substantially 50/50 (by weight).  
     
     
         21 . An instrument as claimed in any one of  claims 1  to  20  in which said bubble generating means is provided at one or more discrete portions along said elongate member.  
     
     
         22 . An instrument as claimed in any one of  claims 1  to  20  in which said bubble generating means is provided along a substantial length of said elongate member.  
     
     
         23 . An instrument substantially as described herein with reference to FIGS.  1  to-of the accompanying drawings.  
     
     
         24 . A method of producing an instrument as claimed in  claim 1  comprising the steps of: 
 c) depositing onto the instrument a first layer containing a first of two elements which, upon contact with each other in the presence of a liquid, react with each other to produce gas bubbles, and  
 d) depositing onto the first layer a second layer containing a second of said two elements.  
 
     
     
         25 . A method as claimed in  claim 24  including the further step of depositing a fluid permeable intermediate layer between said first and second layers.  
     
     
         26 . A method as claimed in  claim 1  or  claim 24  including the further step of depositing a foundation layer on said instrument prior to deposition of said first layer.  
     
     
         27 . A method as claimed in  claim 24  in which the foundation layer comprises a fluid permeable layer.  
     
     
         28 . A method as claimed in any one of  claims 24  to  27  including the further step of depositing a primer layer onto said instrument prior to any of the layers of  claims 1  to  4 .  
     
     
         29 . A method as claimed in any one of  claims 24  to  28  in which the first and second layers comprise a hydrophilic material.  
     
     
         30 . A method as claimed in any one of the  claims 24  to  29  in which said first and second layers comprise Hydrothane™.  
     
     
         31 . A method as claimed in any one of  claims 24  to  30  in which said two elements comprise citric acid and sodium hydrogen carbonate.  
     
     
         32 . A method as claimed in  claim 31  in which said two elements comprise dissolved citric acid and sodium carbonate particles.  
     
     
         33 . A method as claimed in any one of  claims 24  to  32  in which said first layer comprises citric acid and said second layer comprises sodium hydrogen carbonate.  
     
     
         34 . A method as claimed in any one of  claims 24  to  32  in which said first layer comprises sodium hydrogen carbonate and said second layer comprises citric acid.  
     
     
         35 . A method as claimed in any one of  claims 25  to  34  in which said intermediate layer comprises a hydrophilic material.  
     
     
         36 . A method as claimed in any one of  claims 25  to  35  in which said intermediate layer comprises Hydrothane™.  
     
     
         37 . A method as claimed in any one of  claims 24  to  36  including the further step of preparing the instrument surface by solvent degreasing or wet blasting.  
     
     
         38 . A method as claimed in any one of  claims 28  to  37  in which said primer layer comprises an acid etched layer.  
     
     
         39 . A method as claimed in any one of  claims 28  to  37  in which said primer layer comprises a chromate free water based primer (Cytec BR6752) or Chronoflex™ AL80A.  
     
     
         40 . A method as claimed in any one of the  claims 24  to  39  including the step of adding the first and second elements to a carrier material to form said layers and in which said elements are added to said carrier material in a ratio of between 020% and 200% by weight.  
     
     
         41 . A method as claimed in any one of  claims 24  to  40  in which the first and second reactive elements are added in a ratio of substantially 50/50 by weight.  
     
     
         42 . A method as claimed in any one of  claims 24  to  41  including the step of applying the layers at one or more discrete portions along said elongate member.  
     
     
         43 . A method as claimed in any one of  claims 24  to  40  including the step of applying the layers at one or more discrete portions along said elongate member.