Self-cleaning submerged instrumentation

Abstract

Techniques and apparatus inhibit, limit, or remove biofouling and certain inorganic accumulations, to increase the longevity of accurate in-situ oceanographic and other underwater measurements and transducing processes. The invention deters formation of an initial bacterial layer and other precipitation, without harming the environment. The invention integrates an ultrasonic source into a sensor or other device, or its supporting structures. The ultrasonic source vibrates one or more critical surfaces of the device at a frequency and amplitude that dislodge early accumulations, thus preventing the so rest of the fouling sequence. The ultrasonic driver is activated for short periods and low duty cycles, and in some cases preferably while the device is not operating.

What is claimed: 
     
         1 . Apparatus for use with a device that has an exposed window surface, or an exposed active transducing surface that is part of a transducer and is outside any sealed chamber that may be associated with the device, and is (a) critical to performance of the device and (b) operated at least partially submerged within and in direct contact with an aqueous medium and (c) susceptible to biofouling; said apparatus comprising:
 an ultrasonic cleaning system operating at a frequency or frequencies in a range of approximately twenty kilohertz to four hundred kilohertz; and   means for fixing the ultrasonic cleaning system to or integrating the ultrasonic cleaning system into the critical surface, to vibrate the critical surface and thereby reduce or substantially eliminate biofouling of the critical surface, particularly formation of a biofilm on the critical surface.   
     
     
         2 . The apparatus of  claim 1 , wherein:
 the ultrasonic cleaning system is substantially unitary with such device.   
     
     
         3 . The apparatus of  claim 1 , wherein:
 the fixing or integrating means comprises a solid vibration-transmitting structure between the critical surface and the ultrasonic cleaning system.   
     
     
         4 . The apparatus of  claim 1 , wherein:
 the fixing or integrating means comprises a coupling gel or adhesive for transferring vibration from the ultrasonic cleaning system to the critical surface.   
     
     
         5 . Apparatus for use with a device that has an exposed window surface, or an exposed active transducing surface that is part of a transducer and is outside any sealed chamber that may be associated with the device, and is (a) critical to performance of the device and (b) operated at least partially submerged within and in direct contact with a liquid and (c) susceptible to undesirable chemical deposition; said apparatus comprising:
 an ultrasonic cleaning system operating at a frequency or frequencies in a range of approximately fifty kilohertz to eighty kilohertz; and   means for fixing the ultrasonic cleaning system to or integrating the ultrasonic cleaning system into the critical surface, to vibrate the critical surface and thereby reduce or substantially eliminate such chemical deposition.   
     
     
         6 . The apparatus of  claim 5 , wherein:
 the ultrasonic cleaning system is substantially unitary with such device.   
     
     
         7 . The apparatus of  claim 5 , wherein:
 the fixing or integrating means comprises a solid vibration-transmitting structure between the critical surface and the ultrasonic cleaning system.   
     
     
         8 . The apparatus of  claim 5 , wherein:
 the fixing or integrating means comprises a coupling gel or adhesive for transferring vibration from the ultrasonic cleaning system to the critical surface.