Patent Abstract:
The present invention relates generally to the field of endoscopy and specifically to endoscopic apparatus used for endoscopic procedures during which a flexible tube is inserted into the rectum and colon for examination of the colon interior for abnormalities. More particularly, the present invention refers to a control system for supplying a fluid medium, e.g. air, carbon dioxide, water, to the endoscope.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation in part application of application Ser. No. 11/207,092, filed Aug. 18, 2005, and published on Mar. 9, 2006 as US 2006/0052665. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to the field of endoscopy and specifically to endoscopic apparatus used for endoscopic procedures during which a flexible tube is inserted into the rectum and colon for examination of the colon interior for abnormalities. More particularly, the present invention refers to a control system for supplying a fluid medium, e.g. air, carbon dioxide, water, to the endoscope.  
         [0004]     2. Summary of the Prior Art  
         [0005]     Endoscopes employing inflatable flexible sleeves for propulsion of the endoscope within a patient&#39;s colon are known in the art. Voloshin (U.S. Pat. No. 6,485,409) discloses an endoscope with an endoscopic probe, a bending section for directing the probe within the colon (steering unit), an insertion tube and a flexible covering sleeve or a sheath, which is coupled proximally to the probe. The sleeve is attached to the endoscope in such a manner that its folded section is retained between a cap and an internal spindle, which are located at the rear part of the probe. When inflated, the folded section unfolds over a flange of the internal spindle and an inner portion of the sleeve is pulled behind the steering unit in a distal direction.  
         [0006]     Eizenfeld (WO 2004/016299; International application PCT/IL2003/000661) describes an endoscope employing a flexible inflatable sleeve, which before inflation is retained within a dispenser. The dispenser employed in this endoscope has entry and exit ports, defining a transit passage through which the endoscope may pass. The dispenser is adapted to capture the sleeve as the endoscope is retracted through the transit passage in a proximal direction. In another embodiment, the dispenser includes an external sleeve fixed to the dispenser and this external sleeve is adapted to be extended from the dispenser when the endoscope is retracted, so that the external sleeve covers the flexible sleeve. By virtue of this provision any contamination on the flexible sleeve is retained within the external sleeve and does not contact the endoscope or any other objects or areas outside the patient&#39;s body. After the endoscope has been removed entirely from the flexible sleeve, the dispenser together with the external sleeve and flexible sleeve is discarded.  
         [0007]     It is mentioned in the above reference that the endoscope is provided with an internal sleeve, which is also known as a multi-lumen tubing, since it is usually fitted with appropriate passages or lumens as required for irrigation, ventilation, suction and for passing endoscopic tools there through. The proximal end of the multi-lumen tubing is detachably connected via a dedicated connector, or so called hub, to a source of fluid medium and vacuum. A fluid control system is provided, which comprises an external control unit with a pump for supplying compressed air, a flask for supplying water and a pump for producing vacuum. The control unit is provided also with several pinch valves, which control the supply of the compressed air, water and vacuum to the multi-lumen tubing and compressed air to the inflatable sleeve.  
         [0008]     As taught in the parent application Aizenfeld (US 2006/0052665), there is disclosed a new and improved control system and system control unit for supplying fluid medium to the multi-lumen tubing and/or to the inflatable sleeve of an endoscope provided with such a sleeve. This endoscope comprises an operation handle and an insertion tube provided with an insufflation channel, an irrigation channel and a suction channel extending there-along. There is a system control unit with at least one source of a first fluid medium, a source for a second fluid medium, and a source for a vacuum. Optionally, a multifunctional connector may be used for bringing the operation handle in fluid and electrical communication with the system control unit. The at least one source of a first fluid medium and the source for the second fluid medium are simultaneously connectable to and disconnectable from the insufflation channel and the irrigation channel. Compressed air is the first fluid medium for insufflation and water is the second fluid medium for irrigation. The compressed air may come from one or more compression pumps.  
         [0009]     The use of compressed air during endoscopy does, however, have potential risks. The consequences of barotraumas caused during colonoscopic procedure are well documented; see for example article “A retrospective analysis of secal barotraumas caused by colonoscope air and pressure”, Gastrointestinal Endoscopy, 2005, volume  61 , No. 1, 37-45. Accordingly, it is advantageous to use less compressed air, so as to better control any risk of barotraumas.  
         [0010]     It is known that the use of carbon dioxide gas can minimize those risks, otherwise presented by the use of compressed air. The teaching of  NORCCAP: a randomized trial to assess the safety and efficacy of carbon dioxide versus air insufflations in colonoscopy , M Bretthauer, Gut, 2002; 50 604-607, are incorporated in its entirety herein by reference and it discusses the use of carbon dioxide gas instead of compressed air. Using carbon dioxide causes less patient discomfort and is safer during electrosurgical procedures.  
       SUMMARY OF THE INVENTION  
       [0011]     A disadvantage of the device of the parent application is that it is designed to operate solely with compressed air and is not suitable for the inclusion or use of compressed carbon dioxide gas during insufflation, and it operates with compressed air and its attendant risks.  
         [0012]     Thus it is an object of the present invention to improve upon the control system of the parent application and provide a new and improved control system and system control unit for supplying fluid medium to the multi-lumen tubing and/or to the inflatable sleeve of an endoscope provided with such a sleeve, wherein, the control system is suitable to control supply of not only compressed air, but also of carbon dioxide.  
         [0013]     It is a further object of the present invention to provide a new and improved system and system control unit, which is convenient and simple in operation and maintenance.  
         [0014]     Yet another object of the present invention is to provide a new and improved control system and system control unit, which allows the use either of compressed air or of carbon dioxide gas for insufflation and for irrigation and of compressed air for inflating the sleeve.  
         [0015]     For a better understanding of the present invention as well of its benefits and advantages, reference will now be made to the following description of its embodiments taken in combination with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0016]      FIG. 1  depicts a general view of an endoscopic apparatus employing the control system of the present invention.  
         [0017]      FIG. 2   a  depicts the control system and system control unit of the present invention.  
         [0018]      FIG. 2   b  is an enlarged view of a control button.  
         [0019]      FIGS. 3   a  and  3   b  depict a cross-sectional view of the control button.  
         [0020]      FIG. 4  shows a top view of the integral cove in a first embodiment of connecting the SCU with the flask and with the source of compressed carbon dioxide, wherein the connection is provided by virtue of an integral cover closing the flask.  
         [0021]      FIG. 5  shows an alternative embodiment of  FIG. 4 , wherein all inlet and outlet ports are located on a dedicated connection member, which is separate from the cover.  
         [0022]      FIGS. 6 and 7  show various configurations of the connecting member. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     With reference to  FIG. 1  an endoscopic apparatus, preferably a colonoscopic apparatus  10 , is shown with the following main components. The apparatus comprises an endoscope having an insertion tube with its proximal section  12  connected to an operation handle  14  and with its distal section  16  inserted in and protruding from a disposable dispenser  18  in which a disposable inflatable covering sleeve is stored in a folded state before the endoscopic procedure and from which the sleeve feeds out during the endoscopic procedure. An optical head  20  for viewing the interior of the body channel is provided at the distal end of the insertion tube. An example of such an endoscopic apparatus and general explanation of its construction and functioning can be found in Eizenfeld (WO 2004/016299; International application PCT/IL2003/000661), which is herein incorporated by reference.  
         [0024]     It is also shown in  FIG. 1  that a disposable inflatable sleeve covers the distal region of the endoscope. This sleeve comprises a frontal non-inflatable portion  22  and a rear folded portion  24 . The frontal portion covers the distal section of the endoscope, and does not inflate when the endoscope advances within the colon. The rear portion covers the insertion tube and unfolds from the dispenser when compressed air or other fluid medium inflate the sleeve. By virtue of this provision, the endoscope is propelled within the body passage. The endoscope, which can be used with the control system of the present invention, can be of similar type in the sense that it employs the same propelling mechanism, which is based on inflation of the flexible sleeve coupled to the endoscope&#39;s distal section. It should be appreciated, however, that the present invention is not limited merely to the colonoscopy field as such or to endoscopes, which are propelled by an inflatable sleeve. It can be employed in any other endoscopic apparatus used for medical procedures requiring insertion of a probe in a body passage for inspection of its interior.  
         [0025]      FIG. 1  also depicts an operating handle  14  which is connected by an umbilical cord  26  to a system control unit (SCU)  28 , which is deployed on a cart  30 .  
         [0026]     Also proximate to the SCU  28  and attachable to the cart is a flask  32 , filled with water, to be supplied under pressure for irrigation of a window for optical lens provided at the distal end of the optical head. The flask is closed by a detachable cover  34  and is in fluid communication with the SCU and with a sprinkler provided at the distal end of the insertion tube. The sprinkler is designated by reference numeral  36  and is shown in  FIG. 2 .  
         [0027]     As shown in  FIG. 1 , proximate to the cart there is provided a source of compressed carbon dioxide gas. This source can be for example a cylinder  38 , which is in fluid communication with the SCU via a line  40  passing through the flask cover. A pressure regulator  42  can be provided in the line  40  for reducing the carbon dioxide pressure to the required level of about 0.5 bar before carbon dioxide enters the SCU. As will be explained further the system control unit of the invention is versatile in the sense that it may use either compressed air or compressed carbon dioxide gas for insufflation of the colon and for irrigation of the window provided at the optical head. The source of this pressure is either compressed air or compressed carbon dioxide.  
         [0028]     As seen in  FIG. 1  the apparatus is provided with a monitor  44 , which is suitable to display images of the body channel viewed by the optical head as well as various information associated with functioning of the control system.  
         [0029]     One should also bear in mind that within the insertion tube are provided various devices, which are necessary for functioning of the colonoscopic apparatus. These devices are known per se. Among such devices are, for example, vertebrae and strings, which can be manipulated by the operation handle. It should be appreciated, that along the colonoscope extends a multi-lumen tubing with appropriate passages for supplying water, as required for irrigation of the colon, carbon dioxide (and sometime air) as required for insufflation and vacuum as required for suction. The multi-lumen tubing also allows introduction of surgical instruments into the colon as might be required during the colonoscopic procedure.  
         [0030]     The multi-lumen tubing extends through the entire length of the insertion tube, passes the handle and its proximal end  46  is connected to a dedicated connector  48 , which is detachably connectable to a lateral port  50  provided on the handle. The connector connects the proximal end of the multi-lumen tubing with so-called multichannel  52  extending along the umbilical cord. It will be explained further with reference to  FIG. 2 , that the multichannel is fitted with tubes through which fluid media (water, air, carbon dioxide) and vacuum can be supplied from the SCU to the multi-lumen tubing. This arrangement is disclosed in Bar-On (WO 2005/110200; International application PCT/IL2005/000428). It will be also shown further with reference to  FIG. 2  that appropriate channels are provided in the multilumen tubing. These channels are in fluid communication with respective tubes of the multichannel.  
         [0031]     In practice the multi-lumen tubing, the multichannel and the connector are manufactured from plastic material. It is advantageous if they are cheap, disposable items, which are discarded at the end of the endoscopic procedure after the colonoscope has been evacuated form the body passage. By virtue of this provision, preparation for a new colonoscopic procedure is simple, convenient and fast and it is not associated with spreading of any contamination picked up from the body passage during the previous endoscopic procedure.  
         [0032]     Referring now to  FIG. 2   a  a preferred embodiment of the fluid control system of the invention is seen. The system has as a main component, i.e. the SCU  28 , designated by a dotted line, which schematically delimits the SCU housing. The SCU controls supply of compressed air or carbon dioxide, water and vacuum as required for proper functioning of the colonoscopic apparatus  10 . Some external components of the fluid control system, namely cylinder  38  of carbon dioxide, flask  32  of water, vacuum pump unit  54  and monitor  44  are also seen. In practice the flask volume should be sufficient to contain about 300 cc of water. As a suitable source of vacuum one could optionally use available hospital equipment capable of producing a vacuum of about −(0.3-0.5 bar), preferably −0.4 bar to enable suction from the body passage through the multi-lumen tubing. The vacuum pump should be capable to provide a flow rate of at least 20 liter per minute.  
         [0033]     A portion of the multi-lumen tubing extending along the operating handle is also seen in  FIG. 2 . The multi-lumen tubing is provided with channels  56 ,  58  and  60 , which are respectively dedicated to supply air (or carbon dioxide), water and vacuum.  
         [0034]     Within the SCU are provided the necessary electronic, pneumatic and hydraulic components, e.g. a logic unit  62 , first and second pumps  64 ,  66  for producing compressed air, and various solenoids and valves as will be further explained. The logic unit comprises a microcontroller. It is not shown specifically, but should be appreciated that appropriate power supply means is also provided within the SCU as required for activation of the valves, pumps, solenoids and energizing the logic unit.  
         [0035]     Externally positioned near the housing of the SCU is a cylinder  38 , providing a supply of compressed carbon dioxide at a pressure of about 0.5 Bar. The cylinder is detachably connectable to the cover  32  of the flask  32  via external line  40  and then to the SCU via line  68 . A line  70  is provided in the SCU for fluid communication between the SCU and the line  68 . The compressed carbon dioxide is supplied to the SCU through line  68  and then through line  70 . A first connector  72  and a second connector  74  are provided for fast detachable connecting of the cylinder with the cover and of the cover with the SCU. By virtue of this provision the cylinder can be brought in fluid communication with the SCU. The cover and the flask could be disposable. They can be designed as separate items or as a set suitable for supplying to the multilumen tubing the necessary fluid medium, which is either air, or carbon dioxide, or water or vacuum. In  FIGS. 4-8  are presented various embodiments of the cover and a versatile connector member. The will be described later on.  
         [0036]     The logic unit is electrically connected by signal lines  76 ,  78  to respective control buttons  80 ,  82  provided at the operating handle. The button  80  enables controlling of suction through channel  60  made in the multi-lumen tubing. This channel functions either as a suction channel (when vacuum is supplied there through) or as a working channel when it is required to insert a surgical tool through a port  84 . The button  82  enables supply of compressed air or compressed carbon dioxide gas to the body passage through a dedicated insufflation channel  56 . This button also enables supply of water to the distal end of the endoscope or to the body passage through a dedicated irrigation channel  58  and sprinkler  36 . A through going opening  86  is provided in the button  82 . This opening can be closed or opened by the doctor&#39;s finger  88  during operation of the handle. The through going opening is in flow communication with a button mechanism, which resides in the button  82 . In  FIG. 2   b  the button mechanism is presented schematically. A cross-section of the button mechanism is presented in  FIG. 3 .  
         [0037]     As seen in  FIGS. 3   a  and  3   b  the button mechanism comprises a hollow pin  90 , biased by a spring S, wherein the pin is linearly displaceable with respect to the operating handle when the doctor&#39;s finger presses the button. The through going opening  86  extending along the button is in flow communication with a duct  91  provided in the pin  90  and with a lateral duct  92 . The aperture is in fluid communication with an insufflation control line  94  through which compressed air or compressed carbon dioxide gas proceeds from the SCU to the operating handle and can be released to the atmosphere through the control button  82  when the opening  86  is open. Upon closing the opening  86  the pressure in the line  94  raises and this triggers supply of compressed air from the first pump  64  or compressed carbon dioxide gas to the insufflation channel  56 . At one end of the pin there is provided a micro switch  96 , which is actuatable by a shoulder SH, provided laterally at the pin such that the micro switch can close or open a circuit between the signal line  78  and the logic unit  62 . The micro switch is actuated when the pin is forcibly displaced by pressing the button. As will be explained further by closing and opening of the opening  86  as well as by displacement of the pin  90  one could trigger either the insufflation or the irrigation mode. When the opening is closed, but the button is not pressed the insufflation mode is initiated. When the button is pressed to displace the pin the irrigation mode is initiated.  
         [0038]     The components residing within the SCU refer to two main lines for supplying fluid media to the channels of the multilumen. The first line is responsible for insufflation or irrigation and it allows supply of compressed air from the first pump  64 , or compressed dioxide gas from cylinder  38  or water from flask  32 . The second line is responsible for inflating the sleeve and allows supply of compressed air from the second pump  66 . The first pump is preferably controllable by a stepped variation of the voltage supplied thereto so to produce flow of 2-3 l/min at zero pressure or flow of 1.5 l/min at 0.4 bar pressure. These values correspond to those required for insufflation. In other words the pump is deliberately selected in such a manner that its characteristics limit the flow up to certain range and by variation of the voltage supplied to the pump it is possible to vary the flow within the required range.  
         [0039]     The control system further is provided also with a third line for supplying vacuum from the pump  54  to the suction channel  60 .  
         [0040]     Referring to  FIG. 2  the first supply line comprises the first pump  64 , an internal supply line  98 , a first solenoid valve  100  and an internal supply line  98 ′. The exit port of the line  98 ′ is in fluid communication with an external channel  102  of the multichannel  52  and is in fluid communication with the insufflation channel  56  via connector  48 .  
         [0041]     The first supply line further comprises a check valve  104  and a safety valve  106  located in series after the first pump. The check valve prevents back flow from the line  98  to the pump  64 . The check valve should be selected to create pressure drop of about 0.25 psi. and the safety valve should be selected in order to keep pressure in the system below 0.5 bar.  
         [0042]     The compressed air produced by the first pump proceeds via an internal supply line  98 , then via the solenoid valve  100 , via an internal supply line  98 ′ and finally via an external supply line  102  to the insufflation channel  56 . The solenoid valve  100  is in electric communication with the logic unit through a signal line  108 .  
         [0043]     The first supply line further comprises a carbon dioxide supply branch  110 . This branch is in fluid communication with the line  70  as well as with the internal supply line  98  via a knee  112  and with the insufflation control line  94  via a knee  114 . The carbon dioxide supply branch is provided with a first electronic pressure sensor  116  and with the second electronic pressure sensor  118 , which are respectively disposed at right and left side of the knee  114 . Both pressure sensors are in electric communication with the logic unit by respective signal lines  120 ,  122 . The pressure sensors should be capable to measure pressure in the range of up to 1 bar with accurateness of 1-2%.  
         [0044]     A check valve  124  is provided in the carbon dioxide supply branch. The check valve is preferably located between the first pressure sensor and the knee  114 . The check valve prevents back flow from the SCU to the cylinder and it should create pressure drop of about 0.25-0.5 psi.  
         [0045]     The compressed carbon dioxide gas is supplied from cylinder  38  via lines  40 ,  70  and then through the carbon dioxide branch and knee  112  to internal supply line  98 , and then through solenoid valve  100 , internal supply line  98 ′ and external channel  102  to the insufflation channel  56 .  
         [0046]     The first supply line further comprises a second solenoid valve  124 , which can be brought in fluid communication with the first solenoid valve  100  via a line  126  and with atmosphere. The second solenoid valve is in electric communication with the logic unit  62  via a signal line  128 . The first solenoid valve is in fluid communication with the flask  32  by a line  230 . The flask is in fluid communication with the irrigation channel  58  via a channel  232 , which is part of the multichannel  52 . There are provided also two check valves  234 , 236 , which are respectively installed in the channel  232  and in the line  102 . These check valves prevent entering of contamination from the body interior to the SCU. Apart of the above the check valves eliminate a possibility that a doctor will inadvertently activate the insufflation and irrigation when this is not necessary. The valves should be selected in such a manner that they establish a pressure drop of about 1-0.5-2 psi, which is sufficient for eliminating the inadvertent activation. The first supply line should provide insufflation flow of about 1-2 l/min, preferably 1.1-1.8 l/min and irrigation flow of about 1-1.5 cc/sec, preferably 1.3 cc/sec. The insufflation flow rate is controllable in accordance with the user&#39;s requirements.  
         [0047]     The second supply line comprises second pump  66 , which is in fluid communication via a line  238  with an external channel  240 . This channel is in fluid communication with the operating handle  14  and with an inflating channel  242  extending along the insertion tube. Through this channel compressed air is supplied for inflating folded portion  24  of the sleeve. The second supply line further comprises a safety valve  244  and an electronic pressure sensor  246 , which is in electric communication with the logic unit  62  via a signal line  248 . The second pump should produce flow of compressed air of 8 l/min at zero pressure or flow of 5 l/min at 0.4 bar pressure. The safety valve should limit the pressure in the system under 0.6 bar.  
         [0048]     For connecting the SCU with external lines  94 ,  240  supplying the fluid media as well as with signal lines  76 ,  78  a detachable multifunctional connector  250  is provided. This connector is multifunctional in the sense that it enables not only passing electrical signals between the SCU and the control buttons at the operating handle, but also ensures supplying of compressed air from pumps  64 ,  66  or compressed carbon dioxide gas from cylinder  38  to the operating handle  14 . There is provided also a branch  252  in the main connector, which brings in fluid communication a portion of the channel  240  extending along the connector with a foot pedal  254 , which is outside the SCU. The pedal is configured as normally opened switch in the sense that when the pedal is not pressed the compressed air produced by the second pump is released to the atmosphere via line  238 , branch  252  and the pedal. Upon pressing the pedal the compressed air proceeds to the external line  240  and then to the handle  14  and to the inflating channel  242 .  
         [0049]     The line for supplying vacuum comprises vacuum pump  54  or any other available source of vacuum and a suction bottle  256 , which is detachably connectable with a vacuum supply channel  258 . The channel  258  passes via a pinch valve  260  provided at the SCU to supply vacuum in a controllable fashion to the suction channel  60 . The pinch valve is in electric communication with the logic unit via a signal line  262 .  
         [0050]     The channel  258  is also a part of the multichannel and it is seen in  FIG. 2  that channels of the multi-lumen tubing are in flow communication with the respective channels of the multichannel by virtue of connector  48  provided at the lateral port  50  of the handle. The channels  258 ,  232  and  102  respectively supply vacuum to the suction channel  60 , water to the irrigation channel  58  and compressed air or compressed carbon dioxide to the insufflation channel  56 . In accordance with one of the aspects of the present invention, channels for water and compressed air  232 ,  102  are immediately connectable and disconnectable to the respective sources of the fluid media by a common connector  264  without the necessity to connect/disconnect the channels one by one by separate connectors dedicated to each line. This provision renders the set up of the system very simple, convenient and fast. It is not shown specifically, but should be appreciated that, the common connector could be arranged at the flask itself or at its cover.  
         [0051]     The logic unit is electrically connected by a line  266  with the monitor  44  on which are displayed inter alia current working parameters of the SCU and its mode of operation.  
         [0052]     The control system depicted in  FIG. 2  operates as follows. Before activation of any of the desired modes (insufflation, irrigation, suction, inflating) the SCU is turned on and its all relevant components are energized.  
         [0053]     When it is required to inflate the sleeve one should press foot pedal  254 . Upon pressing the pedal a signal is transferred to the logic unit, which, in its turn, generates a control signal that allows compressed air from pump  66  to enter the sleeve via external channel  240 , along the handle and then via inflating channel  242  in the insertion tube. In order to release the pressure from the sleeve, one should release the foot from the pedal. This releases the compressed air produced by pump  66  to the atmosphere via branch  252  and then via the pedal.  
         [0054]     When suction is required, one should press control button  80 . Upon pressing this button, a control signal will be generated by the logic unit to open pinch valve  260  and then vacuum will be allowed to proceed to the body cavity via vacuum supply channel  258  and via suction channel  60  extending along the insertion tube.  
         [0055]     For insufflation by carbon dioxide, one should connect the cylinder with the bottle cover  34  such that fluid communication would be established between cylinder  38 , line  40 , line  68  and line  70 . As soon as carbon dioxide enters in the SCU the first electronic pressure sensor, which is located at the entrance of the carbon dioxide, detects presence of the carbon dioxide and produces a logic signal, which proceeds to the logic unit. The logic signal is transformed by the logic unit into a control signal that turns off the pump  64 . Carbon dioxide proceeds from line  70  via knee  112  to the control line  94  and via knee  114  to the internal supply line  98 . The opening  86  at the control button  82  should be closed by a finger without however pressing the button  82 . In this situation the solenoid valve  100  by default is in the position, in which fluid communication is allowed between the internal supply lines  98  and  98 ′ as well as external supply line  102  and carbon dioxide is allowed to proceed to the insufflation channel  56 . The second pressure sensor senses the current pressure of carbon dioxide being supplied for insufflation. The value of the supplied pressure is send by the logic unit to monitor  44 , where it is displayed along with a notice that the SCU operates in the insufflation mode. Check valve  104  prevents back flow of air from the SCU.  
         [0056]     For effecting mode of irrigation one should deeply press the control button  82 . This causes the micro switch  96  to close a circuit with the signal line  78 . Then a control signal is activated by the logic unit and sent to the solenoid valve  100 . This signal puts the solenoid valve in a position, in which fluid communication is possible between line  98  and line  230 . Accordingly compressed carbon dioxide is allowed to proceed from the cylinder via lines  40 ,  68 ,  110 ,  98  and  230  to the water flask and to urge water to proceed via channel  232  to the irrigation channel  58  until it is ejected via sprinkler  36  to the window of the optical head. In practice it is sufficient if water is supplied for irrigation with a flow of about 1.3 cc per second.  
         [0057]     So long as pressurized carbon dioxide is being supplied to the flask the second solenoid valve  124  is in the position, in which it does not communicate with the atmosphere to prevent release of carbon dioxide through line  126  and then through the solenoid valve  124 . Monitor  44  displays current pressure of carbon dioxide sensed by pressure sensor  118  along with a notice that the SCU operates in the irrigation mode.  
         [0058]     When it is required to terminate the irrigation one should release the control button  82 . This causes generation of a control signal, which puts the solenoid valve  124  in a position, in which it communicated with the atmosphere and thus remaining in the flask pressurized carbon dioxide can be released to atmosphere via line  230 , line  126  and then via solenoid valve  124 .  
         [0059]     The advantage of using two solenoid valves instead of one lies in the fact that miniature components with lesser amount of ports can be employed thus rendering the whole system more compact. At the same time there is no need to increase the amount of logic signals.  
         [0060]     For insufflation by air one should disconnect the cylinder  38  from the SCU and close the opening  86 , without however pressing the control button  82 . In this situation solenoid valve  100  is in a position, in which flow communication is established between line  98  and  98 ′. Pump  64  remains be turned on and produces compressed air, which proceeds through lines  98 ,  98 ′ and  102  to the insufflation channel. In practice the pump should be capable to produce an air flow of about 1.5 liter per minute at a pressure of about 0.4 bar. It is advantageous if this capacity becomes available when a nominal voltage is supplied to the pump. To control the air flow one can vary the nominal voltage. It would be beneficial if the nominal voltage is stepwise reducible to enable control of the air flow. In practice three steps of voltage would be selectable, i.e. 70%, 85% and 100% of the nominal voltage. At the same time pressure of compressed air in the line would be controllable by the safety valve  106 .  
         [0061]     When it is required to terminate the irrigation one should release the control button  82 . This causes generation of a control signal, which puts the solenoid valve  124  in a position, in which it communicated with the atmosphere and thus remaining in the flask pressurized air can be released via line  230 , line  126  and then via solenoid valve  124 .  
         [0062]     Thus by virtue of the SCU of the present invention both the insufflation and the irrigation mode can be carried out either by using of compressed carbon dioxide or compressed air.  
         [0063]     Now with reference to  FIGS. 4-7  various embodiments of connection the SCU with the flask will be described. In  FIG. 4  is shown a first embodiment, in which connection is provided by virtue of an integral cover  34  closing the flask.  FIG. 4  depicts a top view of the integral cover. Within the cover are made ducts, terminating by corresponding inlet and outlet ports for fluid communication with the channels, through which fluid medium is supplied to the SCU, from the SCU to the flask and from the cover to the multichannel. So, for example it is seen that the cover is provided with an inlet port  400 , which is detachably connectable to the line  40  for supplying compressed carbon dioxide. The inlet port  400  is fluid communication with an outlet port  680 , which is connectable to the line  68 , through which the compressed carbon dioxide enters the SCU. Furthermore, the cover is provided with an inlet port  980 ′ for connecting to the line  98 ′, through which either compressed air, or compressed carbon dioxide is supplied from the SCU to the insufflation channel of the multichannel and then to multilumen. The inlet port  980 ′ is in fluid communication with an outlet port  1020 , which is connectable to the channel  102  of the multichannnel. The multichannel is connectable to the cover by the fast releasable connector  264 . The cover is provided further with an inlet port  2300  for supplying compressed air to the bottle via line  230 . The cover is provided also with an outlet port  2320  for connecting to the line  232  of the multichannel through which water is supplied to the irrigation channel in the multilumen. In a preferred embodiment check valves can be installed in ports  980 ′ and  2320 . Fluid communication between ports  2320 ,  1020  and the multichannel is enabled by virtue of entering the multichannel in a female part of the connector  264 .  
         [0064]     In  FIG. 5  is shown an alternative embodiment, in which all inlet and outlet ports are located on a dedicated connection member  268 , which is separate from the cover  34 . In this embodiment fluid communication with the flask  38  is enabled through tubes  270 , 272 , which are connectable to the connection member through corresponding ports. The connection member is made of plastic, for example by injection molding and is configured as a plate with plurality of ports provided laterally at the upper side of the connection member. Two ports at the lower side of the connection member are provided for connecting with tubes  270 ,  272 . So, for example it is seen that the connecting member is provided with an inlet port  400 ′, which is detachably connectable to the line  40  for supplying compressed carbon dioxide. The inlet port  400 ′ is in fluid communication with an outlet port  680 ′, which is connectable to the line  68 , through which the compressed carbon dioxide enters the SCU. Furthermore, the connection member is provided with an inlet port  980 ″ for connecting to the line  98 ′, through which either compressed air, or compressed carbon dioxide is supplied from the SCU to the insufflation channel of the multichannel and then to multilumen. The inlet port  98 ″ is in fluid communication with an outlet port  1020 ′, which is connectable to the channel  102  of the multichannnel. The multichannel is connectable to the appropriated ports of the connector by insertion in the female part  2640  of the fast releasable connector  264 . The connecting member has an inlet port  2300 ′ for connecting to the tube  270  for supplying compressed air to the bottle. The connecting member is provided also with an outlet port  2320 ′ for connecting to the tube  272  for supplying water from the flask to the multichannel and then to the irrigation channel in the multilumen. In a preferred embodiment check valves can be installed in ports  980 ″ and  2320 ′.  
         [0065]     Referring to  FIGS. 6 and 7  there are shown various configurations of the connecting member. The same reference numerals designate similar ports. In these embodiments the tubes  270 ,  272  are in fluid communication with the connecting member not via two separate ports, which are remote from each other but through a combined port  274  suitable for tube in tube disposition.  
         [0066]     It should be appreciated that the invention is not limited to the above-described embodiments and that one of ordinary skill in the art can make modifications or changes without deviating from the scope of the invention, as will be defined in the appended claims.  
         [0067]     It should also be appreciated that the features disclosed in the foregoing description, and/or in the following claims, and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realizing the present invention in diverse forms thereof.  
         [0068]     It should be further appreciated that the pressures and flow rates of various components are given as the preferred pressures and flow rates. Variations in these parameters may be made without affecting the usefulness of the present invention.

Technology Classification (CPC): 0