Patent Publication Number: US-6666818-B2

Title: Modular endoscope valve assembly and method

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 09/761,784, filed Jan. 17, 2001, the entirety of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present invention relates to endoscopic surgical devices, and in particular to valve assemblies used to control the flow of irrigation fluid in such devices. 
     Endoscopic devices are customarily provided with an irrigation port that conducts an irrigation liquid to the viewing area at the end of the endoscopic device. One prior-art approach is to pressurize irrigation fluid in an IV fluid bag, and then to supply the pressurized irrigation fluid directly into an endoscope such as a ureteroscope. The endoscope includes integral valves that are generally operated with one hand while the other hand holds the handpiece of the endoscope. The advantage of this system is that the irrigation fluid is pressurized, thereby providing dilation of a ureter and good visibility. One potential disadvantage with this type of irrigating system is that it may be difficult to control fluid flow since two hands are required. If the fluid flow is not controlled properly, a stone can be dislodged back into the middle or upper ureter by an excessively high rate of flow. Also, in the event of extravasation, uncontrolled amounts of fluid can flow into the retroperitoneum. 
     Another type of irrigation system is a hand-operated, pressurized irrigating system commercially manufactured by Bard, Boston Scientific, and ACMI. This approach allows the amount of fluid being injected to be controlled, but the apparatus is relatively bulky. This system is mounted separately from the ureteroscope, and separate hands are used to hold the handpiece of the ureteroscope and to control the flow of irrigation fluid. On occasion, an assistant controls fluid flow while the physician holds the endoscope in the left hand and performs an endoscopic procedure with the right hand. In this case, precise control of the rate of fluid flow is difficult, because oral instructions are slower and less precise than direct manual control by the physician. 
     A third type of irrigation system includes two or more syringes that are operated by an assistant one at a time to supply pressurized irrigation fluid to the endoscopic device. Generally a valve is provided that allows the assistant to fill one of the syringes while the other is in use. 
     A fourth type of irrigation system includes a roller pump mechanism that delivers irrigation fluid at a constant set pressure. This system may incorporate a blow-off valve to prevent excessive pressure, and it is generally used in endoscopic specialties such as orthopedics in performing arthroscopies. This system requires the use of an electric motor and controller, and it is therefore costly and bulky. 
     Goodman U.S. Pat. No. 4,567,880 discloses an endoscopic device having a three-way valve forming a permanent portion of the handpiece of the endoscope. This system allows a physician to control the flow of irrigation fluid with the same hand as that used to hold the handpiece. However, the Goodman system requires a specially constructed endoscope, and the irrigation system is an integral part of the endoscope. This limits the irrigation system to use with one particular endoscope. 
     The present invention is directed to an improved system and method for controlling the flow of irrigation fluid in an endoscopic device. 
     SUMMARY 
     The preferred embodiment described below includes a modular valve assembly having a housing that carries an inlet port, an outlet port and a valve. The valve can be manually controlled by a user with the hand holding the endoscope to selectively allow or block fluid flow from the inlet port to the outlet port. 
     In use, the housing is releasably mounted to the handpiece of an endoscope by a pressure-sensitive adhesive, strap, or other fastener. The inlet port is connected to a source of pressurized irrigation fluid and the outlet port is connected to the irrigation port of the endoscope. The physician can then use a single hand to perform both the function of holding the handpiece and the function of controlling the flow of irrigation fluid. Typically, the physician holds the handpiece in the palm, using the thumb and fingers of one hand. The physician controls the flow of irrigation fluid with one finger of the hand that is holding the handpiece. This leaves the other hand free for performing a surgical procedure via the working port of the endoscope, e.g., positioning and manipulating a stone extraction basket. Once the surgical procedure is completed, the modular housing can simply be removed from the endoscope and discarded. This eliminates the need to clean the valve or the ports of the valve assembly. 
     The housing may be formed in one or more parts, and it may include a second valve to allow the physician to control the application of suction in addition to the flow of irrigation fluid. 
     This section has been provided by way of general introduction, and it should not be used to narrow the scope of the following claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a ureteroscope on which is mounted a modular valve assembly. 
     FIG. 2 is a top perspective view of the valve assembly of FIG. 1, prior to mounting on the ureteroscope. 
     FIG. 3 is a bottom perspective view of the valve assembly of FIG.  2 . 
     FIG. 4 is a perspective view of the valve assembly of FIGS. 2 and 3 connected to a source of pressurized irrigation fluid. 
     FIGS. 5 and 6 are schematic views showing the valve of the valve assembly of FIGS. 1-3 in the opened and closed positions, respectively. 
     FIGS. 7 and 8 are schematic views of an alternative, rotary-motion valve in the opened and closed positions, respectively. 
     FIG. 9 is a fragmentary sectional view of another modular valve assembly of this invention mounted on a ureteroscope. 
     FIG. 10 is a fragmentary sectional view of yet another modular valve assembly of this invention. 
     FIG. 11 is a fragmentary sectional view of the ureteroscope of FIG. 10 and a cover plate. 
     FIG. 12 is a fragmentary sectional view of another modular valve assembly of this invention mounted on a ureteroscope. 
     FIG. 13 is a cross-sectional view of another modular valve assembly of this invention including a mechanical latch to hold the valve in a selected position. 
     FIGS. 14,  15  and  16  are three sectional views of another modular valve assembly of this invention in three different positions. 
     FIG. 17 is a sectional view of another modular valve assembly of this invention. 
     FIGS. 18,  19  and  20  are side views of three additional modular valve assemblies of this invention. 
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
     Turning now to the drawings, FIG. 1 is a perspective view of an endoscopic device  10  that in this embodiment is a ureteroscope. The ureteroscope  10  includes a handpiece  12  that carries an eyepiece  14  at one end and a shaft  16  at the other end. An irrigation port  18  is carried by the handpiece  12 , and irrigation fluid introduced via the irrigation port  18  is conducted to the viewing area at the end of the shaft  16  that is inserted into the patient. The handpiece  12  also defines an exterior surface  20 . 
     The endoscopic device  10  can take any suitable form, and the present invention is not limited to any particular embodiment. For example, the endoscopes of any of the following U.S. Patents can be adapted for use with this invention: Wallace U.S. Pat. No. 2,691,370, Ibe U.S. Pat. No. 4,132,227, Goodman U.S. Pat. No. 4,567,880, Cho U.S. Pat. No. 5,083,549, Muller U.S. Pat. No. 5,199,417, Bonati U.S. Pat. No. 5,290,279, and Odanacka U.S. Pat. No. 5,830,126. Conventional endoscopes such as the ureteroscopes manufactured by ACMI, Wolf, Olympus and Storz are also well-adapted for use with this invention. This list is intended only by way of illustration, in the widest variety of ureteroscopes, arthroscopes, laparoscopes, hysteroscopes, sinuscopes, and endoscopes adapted for other specialties can be used with this invention, including flexible, semi-rigid, and rigid endoscopes. 
     In use, the physician holds the handpiece with one hand, thereby presenting the eyepiece for viewing and positioning the shaft as desired. The other hand is typically used to manipulate surgical tools introduced into the patient via the working port on the shaft. As shown in FIG. 1, a modular endoscope valve assembly  30  is releasably secured to the handpiece  12 . This valve assembly  30  is shown in greater detail in FIGS. 2 and 3, and it includes an inlet port  32  and an outlet port  34 . In use the inlet port  32  is releasably connected to a source of pressurized irrigation fluid, and the outlet port  34  is releasably connected to the irrigation port  18  of the handpiece. 
     The valve assembly  30  includes a valve that is interposed between the inlet port  32  and the outlet port  34  and is controlled by a valve actuator  38 . The valve assembly  30  also includes a housing  50  that includes a mounting surface  52 . The mounting surface  52  carries a pressure-sensitive adhesive  40  initially covered by a release paper  46 . The housing  50  also supports a pair of straps  42  that include respective hook-and-loop fasteners  44 . A contrast-introduction port  48  is provided in fluid communication with the outlet port  34 . Check valves, not shown, can be provided to prevent flow from the outlet port  34  to the contrast-introduction port  48  and vice-versa. 
     FIG. 4 shows the manner in which the inlet port  32  of the valve assembly  30  can be releasably connected to a source of pressurized irrigation fluid, in this case contained within an IV bag  60 . The IV bag  60  is disposed within a pressure cuff  62  that can be inflated with an inflator  64  to a pressure indicated by a pressure gauge  66 . Standard Luer-lock fittings can be used to connect the inlet port  32  to a tube  68  that is in turn connected to the IV bag  60 . The IV bag contains a conventional irrigation fluid, which is pressurized by inflating the pressure cuff  62  to a desired pressure with the inflator  64 . 
     FIGS. 5 and 6 show two schematic views of the valve  36  of the valve assembly  30 . In FIG. 5 the valve actuator  38  is depressed and the valve  36  allows fluid flow from the inlet port  32  to the outlet port  34 . When manual pressure is removed from the valve actuator  38 , the valve  36  returns to the position of FIG. 6, in which the valve  36  blocks the flow of fluid between the inlet and the outlet ports  32 ,  34 . Alternatively, the valve  38  may be arranged such that fluid flow is blocked when the actuator  38  is depressed and unblocked when the actuator  38  is released. 
     The valve  36  of FIGS. 5 and 6 is a linear valve that slides along a linear axis between the opened position of FIG.  5  and the closed position of FIG.  6 . Other types of valves are suitable, including the linear valve of U.S. Pat. No. 4,238,108 and the rotary valve  80  of FIGS. 7 and 8. A rotary valve  80  rotates about an axis between the opened position of FIG.  7  and the closed position of FIG. 8, and the associated valve actuator (not shown in FIGS. 7 and 8) moves in a rotary motion as well. 
     In use, the valve assembly  30  is distributed separately from the endoscope  10 . In this embodiment, the valve assembly  30  is shaped to fit on a wide variety of endscopes  10  such that the endoscope  10  does not have to be specially shaped or configured for the valve assembly  30 . Prior to an endoscopic procedure, the release paper  46  is removed, thereby exposing the pressure-sensitive adhesive  40  on the mounting surface  52 . Then the valve assembly  30  is placed on the exterior surface  20  of the endoscope  10 , and the pressure-sensitive adhesive  40  releasably holds the valve assembly  30  in place. The straps  42  are positioned around the handpiece  12 , and the hook-and-loop fasteners  44  are secured together to hold the valve assembly  30  in place. 
     Either before or after the valve assembly  30  is secured to the handpiece  12 , the inlet port  32  is releasably secured to the tube  68  (FIG. 4) and the outlet port  34  is releasably secured to the irrigation port  18  of the handpiece  12  (FIG.  1 ). Preferably, the valve assembly  30  is flushed after it is connected to the tube  68  and before it is connected to the irrigation port  18 . 
     The physician then performs the desired endoscopic procedure, using a single hand both to hold the handpiece  12  and to control the flow of pressurized irrigation fluid with the valve assembly  30 . A part of the hand that holds the handpiece (e.g. the fingers or the heel) is used to move the valve actuator. 
     Once the endoscopic procedure has been completed, the valve assembly  30  can simply be removed from the endoscope  10  by releasing the hook-and-loop fasteners  44  and lifting or twisting the valve assembly  10  away from the handpiece  12  until the pressure-sensitive adhesive  40  releases. 
     The valve assembly  30  described above uses both a pressure-sensitive adhesive and a set of straps to releasably secure the valve assembly  30  in place on the handpiece  12 . In alternative embodiments the adhesive may be used without the reinforcing straps, or the reinforcing straps can be used without the adhesive. The strap may be varied widely. For example, the strap may pass over the top of the valve assembly, and the actuator may pass through an opening in the strap. The strap may be fixed to the valve assembly or not. Also, other types of fasteners can be used to releasably hold the valve assembly in place on the endoscope. 
     FIG. 9 shows a second preferred embodiment  90  of the modular valve assembly of this invention. The valve assembly  90  is identical to the valve assembly  30  described above except for the manner of releasably attaching the valve assembly  90  to the handpiece  12 ′. In this case the valve assembly  90  is provided with mechanical fasteners  92  and the handpiece  12 ′ is provided with mating mechanical fasteners  94  such that the valve assembly  90  can be snapped in place on the handpiece  12 ′ and removed from the handpiece  12 ′ as desired. In this example, the fasteners  92  take the form of protruding studs and the mating fasteners  94  take the form of recesses shaped to receive the fasteners  92  in a snap-lock action. 
     FIG. 10 shows portions of a third valve assembly  100  which is similar to that of FIG. 9 except that the fasteners  102  are shaped as recesses and the mating fasteners  104  are shaped as protruding studs that fit into the fasteners  102  in a snap-lock manner. 
     FIG. 11 shows the handpiece  12 ″ of FIG. 10 with a cover  110  snapped in place on the mating fasteners  104 . The cover  110  covers the mating fasteners  104  when a valve assembly is not in place on the handpiece  12 ″. 
     FIG. 12 shows another modular valve assembly  120  mounted in place on the handpiece  12  of an endoscopic device. The valve assembly  120  includes an actuator  122 , an inlet port  124 , and an outlet port  126 . The valve assembly  120  is mounted on a base  130 , and the base  130  supports a spring clip  128  that is designed to fit at least partially around the handpiece  12  and to releasably hold the base  130  and therefore the valve assembly  120  in position on the hand-piece  12 . The spring clip  128  is another example of a mechanical fastener that is suitable for releasably securing a modular valve assembly to an endoscopic device. In this example, the outer surface of the handpiece  12  can be considered a mating fastener that cooperates with the spring clip  128  to releasably hold the valve assembly  120  in place on the endoscopic device. The details of construction of the modular valve assembly  120  can be varied widely, in accordance with any of the other valve assemblies described in this specification. 
     FIG. 13 provides a sectional view of another modular valve assembly  140 . The modular valve assembly  140  includes a housing  142  that supports an inlet port  144  and an outlet port  146 . A valve element  148  is slidably received in a cylinder defined by the housing  142 , and the valve element  148  defines an annular recess  150 . The annular recess  150  completely encircles the valve element  148 , and thereby provides an interconnecting flow path between the inlet port  144  and the outlet port  146  when the recess  150  is aligned with the ports  144 ,  146 . The valve element  148  is biased to the upper position shown in FIG. 13 by a spring  152 . The valve assembly  140  includes an actuator  156  that can be pressed downwardly by a finger of the user. A latch  154  is interposed between the actuator  156  and the valve element  148 , and the latch  154  operates to hold the valve element  148  in a selected position. 
     In use, the inlet port  144  is coupled to a source of irrigation fluid and the outlet port  146  is coupled to the irrigation port of an endoscopic device. In the position shown in FIG. 13, the recess  150  is out of alignment with the inlet and outlet ports  144 ,  146 , and no irrigation fluid is passed to the outlet port  146 . When the user presses the actuator  156  downwardly in the view of FIG. 13, the recess  150  comes into alignment with the inlet and outlet ports  144 ,  146 , thereby permitting irrigation liquid to flow to the endoscopic device. Further downward movement of the actuator  156  causes the latch  154  to hold the valve element  148  in a position in which the recess  150  is aligned with the inlet and outlet ports  144 ,  146 . Once the latch  154  is engaged, the user can take his or her hand off of the actuator  156 , and high volume flow of irrigation fluid is maintained from the inlet port  144  to the outlet port  146 . 
     In order to stop the flow of irrigation fluid, the user again depresses the actuator  156 , thereby causing the latch  154  to release the valve element  148  to move upwardly, back to the position of FIG.  13 . 
     The valve assembly  140  allows the user to modulate the flow of irrigation fluid as described above as he or she gradually depresses the actuator  156 . The latch  154  also allows the user to latch the valve in the open position, until it is released by the user. 
     Many alternative structures can be used for the latch  154 . For example, the latch  154  can be constructed like the latch mechanism conventionally used with retractable ballpoint pens. Such latch mechanisms respond to first depression of the actuator by latching the latched element down, and they respond to a next depression of the actuator by allowing the latched element to move upwardly. This is only one example, and many alternatives are possible. 
     FIGS. 14,  15  and  16  provide three views of another modular valve assembly  160  that can be used as described above. As best shown in FIG. 14, the modular valve assembly  160  includes a housing  162  that supports a valve element  164  for sliding movement. The valve element  164  defines two spaced, annular recesses  166 ,  168 , and the upper end of the valve element  164  forms an actuator  170 . The valve element  164  is biased to the upper position shown in FIG. 14 by a spring  178 . 
     The housing  162  supports first and second inlet ports  172 ,  174  and aligned tubes  173 ,  175  that are connected to an outlet port  176 . The first inlet port  172  in use is connected to a liquid source, such as a source of irrigation fluid. The second inlet port  174  in use is connected to a suction source, such as a partial vacuum. The outlet port  176  in use is connected to an irrigation port of an endoscopic device. Check valves, not shown, may be used to prevent flow from the tube  173  to the tube  175  and vice-versa. 
     In the rest position of FIG. 14, the valve element  164  isolates both the first and second inlet ports  172 ,  174  from the outlet port  176 . This is because the first inlet port  172  is out of alignment with the first recess  166 , and the second inlet port  174  is out of alignment with the second recess  168 . 
     FIG. 15 shows the valve assembly  160  in a second position, in which the user has depressed the actuator  170 , thereby compressing the spring  178  and bringing the first recess  166  into alignment with the first inlet port  172  and the tube  173 . In this position, irrigation fluid from the liquid source is passed by the assembly  160  to the outlet port  176 . 
     As shown in FIG. 16, when the actuator  170  is further depressed, the first recess  166  is moved out of alignment with the first inlet port  172 , and the second recess  168  is moved into alignment with the second inlet port  174 . In this position, the valve assembly  160  allows suction from the suction source to pass via the second inlet port  174  and the second tube  175  to the outlet port  176 . 
     The modular valve assembly  160  of FIGS. 14 through 16 is intended to be removably attached to the handpiece of an endoscopic device, all as described above. Any of the mechanisms described above for releasably securing the valve assembly to the handpiece can be used. The valve assembly  160  provides all of the functions described above regarding the valving of irrigation fluid from the liquid source to the outlet port  176 . In addition, the valve assembly  160  allows the physician efficiently and easily to introduce suction to the endoscopic device by moving the actuator  170  to the fully depressed position of FIG.  16 . Thus, a single valve assembly controls both the introduction of irrigation fluid and the application of suction to the irrigation port of the endoscopic device. 
     The valve assembly  160  utilizes a linear slide valve to implement the valving functions described above. It should of course be understood that this invention is not limited to such linear slide valves, and that the widest variety of valve mechanisms can be used to perform these valving functions. 
     FIG. 17 shows a sectional view of another modular valve assembly  180  also intended to be releasably secured to the handpiece of an endoscopic device as described above. The modular valve assembly  180  includes a housing  182  that supports first and second valve elements  184 ,  185 . The first valve element  184  includes a first recess  186  and a first actuator  190 . The first valve element  184  is biased to the upper position shown in FIG. 17 by a spring  198 . In this upper position the valve element  184  blocks the flow of liquid between a first inlet port  192  and a tube  193 . As shown in FIG. 17, the tube  193  is coupled to an outlet port  196 , which may in turn be coupled to an irrigation port of an endoscopic device as described above (not shown). When the first actuator  190  is depressed to bring the first recess  186  into alignment with the first inlet port  192  and the first tube  193 , irrigation fluid from a liquid source (not shown) passes from the first inlet port  192  to the outlet port  196 . 
     The second valve element  185  defines a second recess  188  and is biased to an upper position as shown in FIG. 17 by a second spring  199 . The upper portion of the second valve element  185  is coupled to a second actuator  191 . In this non-limiting example, the second actuator  191  is arranged so that the physician can reach it from any side of the valve assembly  180 . This can be accomplished by forming the upper portion of the actuator  191  as a ring that encircles the housing  182 . Alternatively, the actuator  191  may include a swivel, not shown, that allows the physician to rotate the upper portion of the actuator  191  to a desired angular position relative to the lower portion of the actuator  191  about an axis parallel to the sliding motion of the second valve element  185 . In the rest position shown in FIG. 17, the second valve element  185  blocks the flow of suction from a second inlet port  194  to the tube  195  (which is in turn coupled to the outlet port  196 ). When the user depresses the second actuator  191  to bring the second recess  188  into alignment with the second inlet port  194  and the second tube  195 , suction is applied to the outlet port  196 . 
     The modular valve assembly  180  is provided with adhesive straps, mechanical fasteners, spring clips or the like for releasably securing it to the handpiece of an endoscopic device (not shown). The modular valve assembly  180  allows the user to control the flow of irrigation fluid and the application of suction to the outlet port  196 . In this case, the user moves his or her finger between the first and second actuators  190 ,  191  to provide irrigation fluid or suction to the outlet port  196 , respectively. 
     FIG. 18 shows another modular valve assembly  210  that performs all of the functions described above in conjunction with FIGS. 16 and 17. The modular valve assembly  210  includes a housing  212 ,  220  that supports two separate valves, each controlled by a respective actuator  214 ,  222 . The actuator  214  controls the flow of irrigation fluid between a first inlet port  216  and an outlet port  218 , and the second actuator  222  controls the introduction of suction from the second inlet port  224  to the outlet port  218 . In this case the actuators  214 ,  222  and the associated valves are positioned in side-by-side relationship, but at differing elevations to assist the user in discriminating between the two actuators  214 ,  222 . 
     The modular valve assembly  230  of FIG. 19 is similar to the valve assembly  210 , except that in this case the two actuators are positioned at the same elevation. 
     The modular valve assembly  240  of FIG. 20 is similar to the modular valve assembly  230 , but in this case the two valves are mounted some distance from one another on the handpiece  12 . FIG. 20 shows the manner in which a housing may include two or more spatially separated parts. 
     The modular valve assemblies of FIGS. 12 through 20 are all intended to be releasably mounted to an endoscopic device and to allow the user to control the flow of at least irrigation fluid to the irrigation port of the endoscopic device. The modular valve assemblies of FIGS. 14 through 20 additionally allow the user to control the application of suction to the irrigation port. The valve assemblies of FIGS. 14 through 20 are used in the same manner as the valves described above, except that the first inlet port  172 ,  192 ,  212  is connected to a source of irrigation fluid and the second inlet port  174 ,  194 ,  224  is connected to a source of suction prior to the surgical procedure. This can be done either before or after the modular valve assembly  160 ,  180 ,  210 ,  230 ,  240  is releasably mounted to the handpiece of the endoscopic device. 
     It should be apparent from the foregoing description that the improved modular valve assembly of this invention provides the important advantage that little or no modification is required to a conventional endoscope, yet the physician using the endoscope is provided with improved control over the flow of irrigation fluid. In particular, the physician can use direct finger pressure to modulate the flow of irrigation fluid as desired, while still leaving one hand free for surgical procedures. In this way, the need for a trained surgical nurse is reduced, and the physician&#39;s control over irrigation fluid flow is improved. The valve assembly described above is well suited for use with a wide variety of endoscopes including modern, small endoscopes that are too small for built-in valves. 
     Of course, it should be understood that a wide range of changes and modifications can be made to the preferred embodiments described above. For example, the valve of the valve assembly can take any suitable form, and it is not limited to the specific examples described above. The motion used to open or close the valve  36  can be varied as appropriate for the application, and it can include a lifting motion, a depressing motion, a sliding motion parallel to the length of the handpiece, or a rotating motion as desired. As a further alternative, the valve may be implemented as an element that pinches a resilient tube to slow or block flow through the tube. Thus, the valve can be implemented as a one-piece or a multiple-piece system having sliding, hinged, rotating or other motions. 
     Similarly, the mechanical fasteners that releasably hold the valve assembly in place on the handpiece of the endoscope can take any suitable form, and such fasteners are not limited to the adhesives, straps, snap-lock studs, and recesses described above. Many other mechanical fasteners can be adapted for use with this invention, as for example linear or rotary guides (including, e.g., dovetail guides or bayonet sockets) and various types of resilient or bendable elements that releasably hold the valve assembly in place. 
     As used herein, the term “position” is intended broadly to encompass a range of positions. Thus, the valve may block fluid flow between the inlet and outlet ports in a range of blocking positions and the valve may allow fluid to flow from the inlet port to the outlet port in a range of opened positions. The valve may be configured as an on/off valve or as a modulating valve. 
     The term “handpiece” is intended broadly to refer to the part of an endoscope that carries the eyepiece and is held by the user, whether referred to as the handpiece, the bridge, or by some other term by the manufacturer of the endoscope. 
     The term “housing” is intended broadly to include one-part housings as well as housings having two or more parts that may be physically integrated with one another or spatially separated from one another. 
     The term “valve” is intended broadly to encompass valves having one or more moveable valve elements controlling the flow of one or more fluids. 
     The term “inlet port” is intended broadly to refer to a port that is connected either to a fluid source or to a suction source. 
     Also, any suitable structure can be used for pressurizing the irrigation liquid, including simple gravity feeds in some examples. 
     The foregoing detailed description has discussed only a few of the many forms that this invention can take. This detailed description is therefore 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.