Patent Publication Number: US-2023157520-A1

Title: Medical cleaning valve

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority from U.S. Provisional Application No. 62/862,893, filed on Jun. 18, 2019, which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to valves for medical devices, particularly endoscopes. 
     BACKGROUND 
     Endoscopes include functionality to deliver fluids (including air and water) and suction to a site of a procedure. Tubing for delivering fluids and/or suction extends from a handle of the endoscope, through a sheath of the endoscope, and to a distal tip of the endoscope. During a procedure, body fluids, tissues, or other material can build up in the tubing and, in some cases, lead to clogging of the tubing. In order to aid in reprocessing of reusable endoscopes between procedures, pre-processing is performed in an endoscopy suite. For example, water or other fluids are flushed through the tubing after the endoscope is removed from a patient, in order to clear debris from the air/water and/or suction tubing. One option for accomplishing such pre-processing is a reusable cleaning valve. The cleaning valve may be inserted into an air/water valve cylinder of an endoscope after the scope is removed from a patient. An operator may then depress a button of the cleaning valve for a predetermined amount of time (e.g., 30 seconds) to flush the air and/or water channels of the endoscope prior to further reprocessing of the endoscope. Such cleaning may require active intervention by an operator. A reusable cleaning valve must be subject to cleaning, itself, in between uses, which can add to reprocessing cost. Therefore, a need exists for valves capable of performing cleaning functions. 
     SUMMARY 
     In one example, a medical valve may comprise a valve stem and an operation portion. The operation portion may include a stationary portion and a movable portion. The movable portion may be movable relative to the stationary portion and fixed relative to the valve stem. A seal may be disposed between the stationary portion and the movable portion. The operation portion may further include a biasing member. Movement of the movable portion in a first direction may cause deformation of the biasing member, such that a restorative force of the biasing member urges movement of the movable portion in a second direction opposite the first direction. A frictional force between the seal and one of the stationary portion and the movable portion resists the movement of the movable portion in the second direction. 
     Any of the medical valves disclosed herein may include any of the following features. The biasing member may be a spring. The movable portion may be movable in the first direction from a first configuration to a second configuration. A relationship between the frictional force and the restorative force may be such that, after the movable portion is transitioned from the first configuration to the second configuration, the movable portion will automatically move in the second direction to return to the first configuration. A radially outer surface of the valve stem may include a first aperture and a second aperture. The valve stem may include a lumen extending along a longitudinal axis of the valve. The lumen may be in fluid communication with the first aperture and the second aperture. A proximal seal, a one-way seal, and three distal seals may be disposed on an outer surface of the valve stem. The first aperture may be between the proximal seal and the one-way seal. The second aperture may be between a first of the three distal seals and a second of the three distal seals. The valve may be movable in a proximal direction and a distal direction relative to a valve cylinder that receives the valve. The valve may be rotatable about a longitudinal axis of the valve and relative to a valve cylinder that receives the valve. A first and a second rotatable seal may be disposed on the valve stem. In a first configuration of the valve, a first hole in the first rotatable seal and a second hole in the second rotatable seal may face a first direction. In a second configuration of the valve, the first hole and the second hole may face a second direction different from the first direction. The valve may also include an O-ring seal between the first rotatable seal and the second rotatable seal. The first hole may be aligned with a first aperture in a radially outer surface of the valve stem. The second hole may be aligned with a second aperture in the radially outer surface of the valve stem. Each of the first and second rotatable seals may include a recessed notch extending partially around an outer circumference of the rotatable seal. The first hole may be within the recessed notch of the first seal. The second hole may be within the recessed notch of the second seal. The movable portion may include a rim that extends between inner and outer cylindrical portions of the stationary portion. The stationary portion may include a mating feature for mating with a valve cylinder of an endoscope. The valve stem may be a single, unitary structure formed of a single material. 
     In another example, a medical valve may comprise a movable portion movable between a first configuration and a second configuration; a stationary portion, a seal disposed between the stationary portion and the movable portion and providing a frictional force between the stationary portion and the movable portion; and a spring. Transitioning the movable portion from the first configuration to the second configuration may deform the spring. The deformed spring may exert a restorative force urging the movable portion back to the first configuration. A relationship between the frictional force and the restorative force may be such that, after the movable portion is transitioned from the first configuration to the second configuration, the movable portion will automatically return to the first configuration after an amount of time. 
     Any of the medical valves disclosed herein may include any of the following features. The valve may be movable in a proximal direction and a distal direction relative to a valve cylinder that receives the valve. The valve may be rotatable about a longitudinal axis of the valve and relative to a valve cylinder that receives the valve. 
     A method for cleaning an endoscope may comprise providing a force to a valve to transition the valve from a first configuration in which water is not delivered to an air channel to a second configuration in which water is delivered to an air channel; and releasing the force. After the force is released, the valve may continue to deliver water to the air channel for an amount of time before automatically transitioning back to the first configuration. 
     Any of the methods disclosed herein may include the following steps or aspects. The valve may include a movable portion; a stationary portion; a seal disposed between the stationary portion and the movable portion and providing a frictional force between the stationary portion and the movable portion; and a spring. Transitioning the movable portion from the first configuration to the second configuration may deform the spring. The deformed spring may exert a restorative force urging the movable portion back to the first configuration. A relationship between the frictional force and the restorative force may be such that, after the movable portion is transitioned from the first configuration to the second configuration, the movable portion will automatically return to the first configuration after the amount of time. 
     It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.” As used herein, the term “proximal” means a direction closer to a surface used by an operator for operating a valve (e.g., a button) and the term “distal” means a direction away from the surface used by an operator for operating a valve (e.g., a button). Although endoscopes are referenced herein, reference to endoscopes or endoscopy should not be construed as limiting the possible applications of the disclosed aspects. For example, the disclosed aspects may be used with duodenoscopes, bronchoscopes, ureteroscopes, colonoscopes, catheters, diagnostic or therapeutic tools or devices, or other types of medical devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate examples of the present disclosure and, together with the description, serve to explain the principles of the disclosure. 
         FIGS.  1 A and  1 B  show cross-sectional views of a first exemplary valve. 
         FIGS.  2 A and  2 B  show cross-sectional views of a second exemplary valve. 
         FIGS.  3 A- 3 D  show exemplary seals that may be used in conjunction with the second exemplary valve of  FIGS.  2 A and  2 B . 
     
    
    
     DETAILED DESCRIPTION 
     A valve may be configured to provide cleaning functionality to an air channel of an endoscope. In at least some embodiments, the valve may be appropriate for a single-use and therefore be disposable. In a first configuration, the valve may provide neither air nor water flow to air and/or water channels of an endoscope. In a second configuration, the valve may provide only water flow to only an air channel of the endoscope. The valve may include features that, after the valve is transitioned from the first configuration to the second configuration, retain the valve in the second configuration for a predetermined amount of time, such as a time specified for flushing an air valve in a cleaning protocol. Thus, the valve may be in a second, flushing configuration for a predetermined amount of time without active participation by a user, so that the user may perform other tasks during the flushing of the air channel of the endoscope. After the predetermined amount of time, the valve may transition from the second configuration back to the first configuration automatically. 
       FIGS.  1 A- 1 B  show cross-sectional views of a first exemplary cleaning valve  10  in a valve cylinder  39 .  FIG.  1 A  shows valve  10  in a first configuration, and  FIG.  1 B  shows valve  10  in a second configuration. Valve cylinder  39  may have a water inlet A, a water outlet B, an air inlet C, and an air outlet D. Water inlet A may be in fluid communication with a source of water or other liquid (e.g., water, cleaning solution, air, other gases, or combinations thereof). Water outlet B may be in fluid communication with a water channel of an endoscope (not shown), which may extend from a proximal end of the endoscope to a distal end of the endoscope. During a medical procedure, the water channel may be used to deliver water at a site of the procedure. Air inlet C may be in fluid communication with a source of air or other fluid (e.g., air, other gases, water, or cleaning solution, or combinations thereof). Air outlet D may be in fluid communication with an air channel of the endoscope. During a medical procedure, the air channel may be used to deliver air at a site of the procedure. 
     Valve  10  may have a proximal end  12  and a distal end  14 . A valve stem  16  may extend from proximal end  12  to distal end  14 . A cap  18  (which may be an operation portion of valve  10 ) may be disposed at proximal end  12 . Valve stem  16  may be a single, unitary structure formed of a single, continuous piece of material and may be made from a metal (e.g., stainless steel, titanium, aluminum, etc.), from a polymer (e.g. polycarbonate, ABS, HDPE, Nylon, PEEK, thermoplastic, plastic, etc.), or from any other suitable material. Depending on the material used, valve stem  16  may be machined, injection molded, extruded (via, e.g., 3D printing), or otherwise formed. Valve stem  16  may be formed of a clear thermoplastic so that certain portions of an interior of valve stem  16  are visible through external walls of inner cylindrical member. 
     Valve stem  16  may have a lumen  22  extending through a central longitudinal axis of valve stem  16 . Alternatively, lumen  22  may extend through another longitudinal axis of valve stem  16  (e.g., lumen  22  may be off-centered). A space between an exterior surface of valve stem  16  and a surface defining lumen  22  may be solid, and lumen  22  may be a bore formed in valve stem  16 . In another example, a space between an exterior surface of valve stem  16  and a surface defining lumen  22  may be hollow. In such a case, lumen  22  may be formed by a longitudinal tube within valve stem  16 . 
     Lumen  22  may be open to an exterior of valve stem  16  on a proximal end of lumen  22  via one or more proximal apertures  24 . For example, lumen  22  may be fluidly connected to proximal aperture(s)  24  via a second, proximal lumen (not shown) which may be transverse to lumen  22 . For example, the second lumen may be perpendicular to lumen  22  (extending into the page in  FIG.  1 A ). Lumen  22  may be open to an area exterior of valve stem  16  on a distal end of lumen  22  via one or more distal apertures  26 . Lumen  22  may be fluidly connected to distal aperture(s)  26  via a third, distal lumen (not shown) which may be transverse to lumen  22 . For example, the third, distal lumen may be perpendicular to lumen  22  (extending into the page in  FIG.  1 A ). 
     Valve stem  16  may have disposed on it a first distal seal  32 , a second distal seal  34 , and a third distal seal  36 . Distal seals  32 ,  34 ,  36  may be made from elastomeric material. Distal seals  32 ,  34 ,  36  may be identical to one another and may be, for example, O-rings. Distal seals  32 ,  34 ,  36  may be disposed in circumferential, annular grooves or indentations on valve stem  16 . A durometer value and outer diameter of distal seals  32 ,  34 ,  36  may be such that the distal seals  32 ,  34 ,  36  have an interference fit with an inner surface  38  of an endoscope valve cylinder  39  when valve  10  is inserted in endoscope valve cylinder  39 . The interference fit may be loose enough so that valve stem  16  may slidably move relative to surface  38  but tight enough so that fluids cannot flow longitudinally between a radially outermost surface of seals  32 ,  34 ,  36  and surface  38 . Third distal seal  36  may be disposed near to a distal end  14  of valve  10 , distal to distal aperture  26 . Second distal seal  34  may be proximal of third distal seal  36  and proximal to distal aperture  26 . First distal seal  32  may be proximal of second distal seal  34  but still distal of proximal aperture  24 . 
     Valve stem  16  may also have disposed on it a proximal seal  42 . Proximal seal  42  may have any of the properties of distal seals  32 ,  34 ,  36 . For example, proximal seal  42  may be an elastomeric O-ring and may be disposed in an annular circumferential groove or indentation of valve stem  16 . A durometer value and outer diameter of proximal seal  42  may be such that the proximal seal  42  has an interference fit with surface  38  (see  FIGS.  1 A- 1 B ) when valve  10  is inserted in endoscope valve cylinder  39 . The interference fit may be loose enough so that valve stem  16  may slidably move relative to endoscope valve cylinder surface  39  but tight enough so that fluids cannot flow longitudinally between a radially outermost surface of proximal seal  42  and surface  38 . Proximal seal  42  may have a larger inner diameter than distal seals  32 ,  34 ,  36  due to a small diameter of the groove within valve stem  16  at a location of proximal seal  42 . Proximal seal  42  may have a larger outer diameter than distal seals  32 ,  34 ,  36  due to a wider space defined by surface  38  at the location of seal  42  compared to a space defined by surface  38  at the location of seals  32 ,  34 ,  36 . It is understood that seals  32 ,  34 ,  36 , and  42  may be any size to fit around the valve stem  16  and to seal against surface  38  to selectively prevent fluid flow. 
     Valve stem  16  may also be fitted with a one-way seal  62 , which may be disposed longitudinally along the valve stem  16  between first distal seal  32  and proximal seal  42 . One-way seal  62  may be formed of an elastomeric material, which may stretch to fit over valve stem  16 . One-way seal  62  may be disposed in a groove or indentation of valve stem  16 . An inner surface of one-way seal  62  may be sized so that there is a slight interference between an external surface of valve stem  16  and the inner surface of one-way seal  62 , so that a tight seal is formed. An outer diameter of one-way seal  62  may be sized so as to form a slight interference fit with surface  38  (see  FIGS.  1 A- 1 B ). A thin flap of one-way seal  62  may extend radially outward from valve stem  16  at an angle transverse to a longitudinal axis of valve stem  16 . For example, the thin flap may extend at an angle between approximately 10 degrees and 80 degrees relative to a longitudinal axis of valve stem  16 . The flap of one-way seal  62  may be expandable so that when fluid (e.g., water or air) moves in a distal direction, a positive pressure will expand the flap, maintaining a seal between one-way seal  62  and surface  38  (see  FIGS.  1 A- 1 B ). Fluid moving proximally will also create a positive pressure, but the positive pressure will produce a force normal to a longitudinal axis of valve stem  16  to radially compress the flap of one-way seal  62  toward valve stem  16 . Thus, fluid (e.g., air or water) is permitted to move proximally past one-way seal  62 , between one-way seal  62  and surface  38 . 
     Proximal aperture  24  may be disposed axially between one-way seal  62  and proximal seal  42 . Distal aperture  26  may be disposed axially between third distal seal  36  and second distal seal  34 . 
     Cap  18  may have a stationary portion  70  and a movable portion  72 . Although movable portion  72  is described herein as being separate from valve stem  16 , it will be appreciated that movable portion  72  and valve stem  16  could be formed of a single integral piece. Stationary portion  70  may remain stationary with respect to valve cylinder  39  when valve  10  is inserted in valve cylinder  39 . Stationary portion  70  may include an inner cylindrical member  74  and an outer cylindrical member  76 . As shown in  FIGS.  1 A- 1 B , inner cylindrical member  74  and outer cylindrical member  76  may be made from a single, unitary piece of material, which may facilitate manufacturing efficiencies. Alternatively, inner cylindrical member  74  and outer cylindrical member  76  may be two separate pieces that are assembled together. Outer cylindrical member  76  may include one or more mating features  78  for mating cap  18  with an outer portion of valve cylinder  39 . For example, mating feature  78  may be a protrusion extending radially inward and matable with a corresponding groove or indentation of valve cylinder  39 . A distal surface of inner cylindrical member  74  may rest upon a proximal outer surface of valve cylinder  39 . A cross-section of inner cylindrical member  74  may be “L” shaped, forming a seat, for a spring (to be described, below). 
     Movable portion  72  may be proximally and distally (axially) movable relative to valve stem  16  and/or stationary portion  70 . Movable portion  72  may be affixed to valve stem  16 , so that proximal or distal (axial) movement of movable portion  72  also causes the same motion of valve stem  16 . As discussed above, movable portion  72  may be integrally formed with valve stem  16 . Movable portion  72  of cap  18  may have a button shape or any other suitable shape. A rim  80  of movable portion  72  may extend in a longitudinal direction between outer cylindrical member  76  and inner cylindrical member  74 . 
     Cap  18  may be fitted with a spring  82 , which may be a biasing member. Spring  82  may be a coil spring, leaf spring, or another type of resilient member, such as any member having shape-memory properties. Spring  82  may be, for example, a compression spring. Spring  82  may be configured in cap  18  so that, when spring  82  is in a relaxed state, valve  10  has a first configuration relative to stationary portion  70 . When movable portion  72  is moved distally so that valve  10  has a second configuration, spring  82  may be in a deformed, compressed state and may store potential energy due to the deformation (e.g., compression) of spring  82 . Spring  82  may have properties, including a stiffness, such that spring  82  exerts a known return force on movable portion  72  after it has been moved distally from the first configuration to the second configuration. 
     A cap seal  90  may be disposed between movable portion  72  and stationary portion  70 . Cap seal  90  may be, for example, an O-ring seal, a washer, or other type of structure and may be formed of elastomeric material. Alternatively, something other than a seal that provides a resistive or frictional force between movable portion  72  and stationary portion  70  may be used in place of cap seal  90 . For example, instead of cap seal  90 , portions of movable portion  72  or stationary portion  70  may be textured or may have structures or substances disposed thereon that increase resistance between them. As shown in  FIGS.  1 A and  1 B , cap seal  90  may be fixed to movable portion  72 , in an annular groove within movable portion  72 , and cap seal  90  is movable with respect to stationary portion  70 . Alternatively, cap seal  90  may be fixed to stationary portion  70  and movable with respect to movable portion  72 . Cap seal  90  may provide a frictional force between an outer surface of cap seal  90  and an inner surface of stationary portion  70 . Thus, when valve  10  is in the second configuration, and spring  82  is in a deformed, compressed state, friction caused by cap seal  90  may resist a return force of spring  82  that urges movable portion  72  and valve stem  16  proximally to the first configuration, in which spring  82  is relaxed. The relationship between a frictional force caused by cap seal  90  and a return force caused by spring  82  may be such that valve  10  automatically moves from the second configuration to the first configuration in a set, predetermined amount of time. In other words, the frictional force may delay the return of valve  10  to the first configuration. The delay may align with a time desired to flush an air channel of an endoscope, as discussed below. 
     A stem seal  91  may be disposed between stationary portion  70  and valve stem  16 . Stem seal  91  may be, for example, an O-ring seal, a washer, or other type of structure and may be formed of elastomeric material. As shown in  FIGS.  1 A and  1 B , stem seal  91  may be fixed to stationary portion  70 , in an annular groove within stationary portion  70 , and stem seal  91  is movable with respect to valve stem  16 . Alternatively, stem seal  91  may be fixed to valve stem  16  and movable with respect to stationary portion  70 . Stem seal  91  may be configured such that fluids (e.g., air or water) cannot pass proximally or distally of stem seal  91 . 
       FIG.  1 A  shows valve  10  in a first configuration, in which air is flushed through both a water channel and an air channel of an endoscope. In the first configuration, spring  82  may be in a relaxed state, and movable portion  72  may be in a raised position, as a result. In the first configuration, third distal seal  36  may be positioned proximal to a water inlet A of endoscope valve cylinder  39  and also distal to a water outlet B of endoscope valve cylinder  39 . Second distal seal  34  may be proximal of water outlet B but distal to air inlet C. First distal seal  32  may also be distal to air inlet C. One-way seal  62  may be proximal of air inlet C and distal to air outlet D. 
     Thus, in the first configuration, water, or other fluid, from water inlet A may not move proximally past third distal seal  36  and may thus not move to water outlet B. Air, or other fluid, from air inlet C may not move distally along an outer surface of valve stem  16  due to first distal seal  32 . However, air from air inlet C may move proximally past one-way seal  62 . Air may thus pass into air outlet D and also into proximal aperture  24 . Air that has passed into proximal aperture  24  may pass distally through lumen  22  and out of distal aperture  26 . Because distal aperture  26  is between third distal seal  36  and second distal seal  34 , the air exiting distal aperture  26  may not move proximally or distally along an outer surface of valve stem  16 . However, the air exiting distal aperture  26  may exit the water outlet B. The first configuration may be used after flushing an air channel of an endoscope to ensure that water is removed from the air channel and the water channel before the scope is subject to further reprocessing. 
       FIG.  1 B  shows valve  10  in a second, compressed configuration, in which water is flushed down the air channel. Spring  82  may be compressed in the second configuration so that movable portion  72  is translated distally relative to the first configuration. An entirety of valve stem  16  is shifted distally by a same amount by which movable portion  72  is shifted. Proximal seal  42  may remain proximal of air outlet D. One-way seal  62  may be shifted distally relative to the first configuration, so that air or other fluid from air inlet C may not move past one-way seal  62  (e.g., fluid flow is prevented) because a distal portion of one-way seal  62  fits in a narrowed, tapered region of endoscope valve cylinder  39  so that air cannot flow proximally past the distal portion of one-way seal  62  to reach the proximal movable flap portion of one-way seal  62 . 
     In the second configuration, third distal seal  36  may be distal to water inlet A, and second distal seal  34  may remain proximal of water inlet A. Therefore, water or other fluid from water inlet A may enter proximally of third distal seal  36  but may not move proximally past second distal seal  34  along an outer surface of valve stem  16 . However, water or other fluid may enter distal aperture  26  and travel through lumen  22  and through proximal aperture  24 . After water or other fluid exits proximal aperture  24 , the water may not flow distally past one-way seal  62  or proximally past one-way seal  62 . However, water or other fluid may flow out air outlet D to flush out the air channel of an endoscope. 
     If an operator releases movable portion  72  of cap  18  after transitioning valve  10  from the first configuration ( FIG.  1 A ) to the second configuration ( FIG.  1 B ), valve  10  will slowly move back to the first configuration due to restorative forces exerted by spring  82 . However, valve  10  may not immediately return back to the first configuration due to frictional forces caused by cap seal  90 . For example, cap seal  90  may exert forces opposite forces exerted by spring  82 , thereby delaying relaxation of the spring  82  and return to the first configuration of the valve  10 . Valve  10  may continue to deliver water or other fluid to air outlet D until third distal seal  36  passes proximally of water inlet A. Thus, valve  10  may deliver water or other fluid to air outlet D for a predetermined amount of time, which may be specified by a cleaning protocol, without a user pressing on portion  72  of cap  18 . For example, cap seal  90  and spring  82  may be calibrated so as to flush an air channel for a particular, predetermined amount of time. 
     After a procedure using an endoscope is completed, an operator may remove an air/water valve used during the procedure from valve cylinder  39 . The operator may then insert valve  10  into valve cylinder  39 . Distal portion  76  cap  18  may be secured to valve cylinder  39  using mating feature  78 . 
     Valve  10  may be inserted into valve cylinder  39  in the first configuration of valve  10 . An operator may press down movable portion  72 , which compresses spring  82 , and shifts valve stem  16  downward, relative to valve cylinder  39  and stationary portion  70 . The user may then release movable portion  72  and may attend to other aspects of a post-operative procedure. Even without operator intervention, valve  10  may be maintained in the second, compressed configuration for a predetermined amount of time (e.g., thirty seconds) so as to flush water through an air channel of the endoscope, thereby removing debris from the air channel. As discussed above, interactions between spring  82  and cap seal  90  may facilitate automatically flushing water for a predetermined amount of time. Movable portion  72  (and valve stem  16 ) may eventually return to the first configuration due to a force exerted by spring  82 , as discussed above. Following completion of flushing of water through the air channel, valve  10  may be disposed. 
     Turning to  FIGS.  2 A and  2 B , a second exemplary valve  100  may include a valve stem  116  and a cap  118  (which may be an operation portion of valve  100 ). Valve  100  may be installed into a valve cylinder  139 , which may have any of the properties of valve cylinder  39 . Valve  100  may have any of the properties of valve  10 . 
     Valve stem  116  may be formed of any suitable material, including any of those outlined above with respect to valve stem  16  and may have any of the properties of valve stem  16 . Valve stem  116  may include a lumen  122 , which may have any of the properties of lumen  22 . Lumen  122  may be substantially formed along a central longitudinal axis of valve stem  116  or along another, off-center longitudinal axis of valve stem  116 . Alternatively, at least a portion of lumen  122  may be transverse to a longitudinal axis of valve stem  116 . Lumen  122  may have a proximal bend  124  and a distal bend  126 . A midsection  128  of lumen  122  may be between proximal bend  124  and distal bend  126 . Lumen  122  may bend up to 90 degrees, approximately 90 degrees, or any other suitable amount at proximal bend  124  and/or distal bend  126 . A proximal end of lumen  122  may terminate at a proximal opening or aperture  130 . Proximal opening  130  may extend through a wall of valve stem  116  and may cause lumen  122  to be in fluid connection with an area exterior to valve stem  116 . A distal end of lumen  122  may terminate at a distal opening or aperture  132 . Distal opening  132  may extend through a wall of valve stem  116  and may cause lumen  122  to be in fluid connection with an area exterior to valve stem  116 . Proximal opening  130  and distal opening  132  may be radially aligned on valve stem  116 . Proximal bend  124  and/or distal bend  126  may be omitted. If proximal bend  124  is omitted, proximal opening  130  may be in direct communication with midsection  128  of lumen  122 . Similarly, if distal bend  126  is omitted, distal opening  132  may be in direct communication with midsection  128  of lumen  122 . Valve stem  116  may be fitted with a proximal rotation seal  140 , a distal rotation seal  142 , and a middle rotation seal  150 . 
       FIG.  3 A  shows an exemplary seal  200 , the basic structure of which may be used for distal rotation seal  142 . Seal  200  or features of seal  200  may also be used for proximal rotation seal  140  and/or middle rotation seal  150 . Seal  200  may be made from any appropriate material, and may be elastomeric. As shown in  FIG.  3 A , seal  200  may be annular and may have a roughly washer or O-ring shape. Seal  200  may have an inner opening  202  defined by an inner surface  203 . Surface  203  may be fit around a circumference of valve stem  116  so that inner surface  203  is in contact with an outer surface of valve stem  116 . An outer surface  204  of seal  200  may contact inner surface  138  of valve cylinder  139 , when valve  100  is inserted into valve cylinder  139 . Surfaces  203  and  204  may be flat; in other words, a wall defining opening  202  may have a substantially uniform thickness, except in the areas of a hole  210  and a notch  212  to be described. Hole  210  may be formed through a wall of seal  200 , extending from a surface defined by notch  212  to inner surface  203 . Outer surface  204  of seal  200  may define a recessed notch  212 , which may surround hole  210 . Notch  212  may have an have a substantially rectangular cross-section and may extend at least partially around a circumference outer surface  204 , past hole  210 . Notch  212  may extend circumferentially past hole  210  in both directions (as shown) or only in one direction or the other (e.g., notch  212  may terminate near hole  210 ). Notch  212  may have a similar width (in an axial direction) to a diameter of hole  210 , or notch  212  may have a width (in an axial direction) that is smaller than a diameter of hole  210 . Notch  212  may have a thickness (in a radial direction) such that it extends partially through a wall defining opening  202  but not entirely through the wall defining opening  202 . A function of notch  212  will be discussed in further detail below. 
       FIG.  3 B  shows an exemplary seal  300 , the basic structure of which may be used for middle rotation seal  150 . Seal  300  may have any of the features of seal  200 , discussed above. Seal  300  or features of seal  300  may also be used for proximal rotation seal  140  and/or distal rotation seal  142 . Seal  300  may be made from any appropriate material, and may be elastomeric. As shown in  FIG.  3 B , seal  300  may be annular and may have a roughly washer or O-ring shape. Seal  300  may have an inner opening  302  defined by an inner surface  303 . Surface  303  may be fit around a circumference of valve stem  116  so that inner surface  303  is in contact with an outer surface of valve stem  116 . An outer surface  304  of seal  300  may contact inner surface  138  of valve cylinder  139 , when valve  100  is inserted into valve cylinder  139 . Surfaces  303  and  304  may be flat; in other words, a wall defining opening  302  may have a substantially uniform thickness, except in the areas of a notch  320  to be described. Outer surface  304  of seal  300  may define a recessed notch  320 , which extend along a longitudinal length of seal  300 . Notch  320  may have an have a substantially rectangular cross-section. A function of notch  320  will be discussed in further detail below. Alternatively, seal  300  may not have a full annular shape and may instead extend around only a portion of a circumference of valve stem  116 . In such a configuration, notch  320  may be omitted from seal  300 . 
       FIGS.  3 C and  3 D  show another exemplary seal  400 , the basic structure of which may be used for proximal rotation seal  140 . Seal  400  may have any of the features of seals  200 ,  300 , discussed above. Seal  400  or features of seal  400  may also be used for distal rotation seal  142  and/or middle rotation seal  150 . Seal  400  may be made from any appropriate material, and may be elastomeric. Seal  400  may be annular and may have a roughly washer or O-ring shape. Seal  400  may have an inner opening  402  defined by an inner surface  403 . Surface  403  may be fit around a circumference of valve stem  116  so that inner surface  403  is in contact with an outer surface of valve stem  116 . An outer surface  404  of seal  200  may contact inner surface  138  of valve cylinder  139 , when valve  100  is inserted into valve cylinder  139 . Surfaces  403  and  404  may have any of the features of surfaces  303 ,  304 , discussed above. Hole  410  may be formed through a wall of seal  400 , extending from a surface defined by notch  412  to inner surface  403 . Outer surface  404  of seal  400  may define a recessed notch  412 , which may surround hole  410 . Hole  410  and notch  412  may have any of the features of hole  210  and notch  212 , respectively, as discussed above. Outer surface  404  of seal  400  may define a recessed notch  420 , which extend along a longitudinal length of seal  400 . Notch  420  may have any of the properties of notch  320 , discussed above. Notch  420  may be disposed diametrically opposite of hole  410  or at another angle relative to hole  410 . Alternatively, seal  400  may not have a full annular shape and may instead extend around only a portion of a circumference of valve stem  116 . In such a configuration, notch  420  may be omitted from seal  400 . 
     As discussed above, proximal rotation seal  140 , distal rotation seal  142 , and middle rotation seal  150  may have features of seals  200 ,  300 ,  400 , discussed above. Proximal rotation seal  140 , distal rotation seal  142 , and middle rotation seal  150  may have different inner and/or outer diameters, in order to accommodate different diameters of valve stem  116  and/or valve cylinder  139  at the respective locations of proximal rotation seal  140  and distal rotation seal  142 . 
     Proximal rotation seal  140  (which may have any of the structures described above, with respect to seal  400 ), may be positioned so that a hole  146  (which may have any of the properties of hole  410 ) of proximal rotation seal  140  aligns with proximal opening  130 . A notch  147  of proximal rotation seal  140  (which may have any of the properties of notch  420 ) may be positioned so that it is 180 degrees (diametrically opposed) from proximal opening  130  or at a different angle relative to proximal opening  130  (as discussed below). 
     Distal rotation seal  142  (which may also have any of the structures described above, with respect to seal  200 ) may be positioned so that a hole  148  (which may have any of the properties of hole  210 ) of distal rotation seal  142  aligns with distal opening  132 . Thus, lumen  122  may be in fluid communication with an exterior surface of proximal rotation seal  140  and distal rotation seal  142 , via holes  146  and  148 , respectively. 
     Middle rotation seal  150  (which may also have any of the structures described above, with respect to seal  300 ) may be positioned so that a notch  151  (which may have any of the properties of notch  320 ) is positioned in line with notch  147  of proximal rotation seal  140 . Middle rotation seal may be positioned 180 degrees (diametrically opposed from) proximal opening  130  and distal opening  132 , or at another angle relative to proximal opening  130  and distal opening  132  (as discussed below). 
     Proximal rotation seal  140 , distal rotation seal  142 , and middle rotation seal  150  may be configured so that each has a slidable interference fit with an inner surface  138  of valve cylinder  139  when seals  140 ,  142 ,  150  are positioned about valve stem  116 . Fluids, such as air and/or water, may not move proximally or distally past distal rotation seal  142 , between an outer surface of valve stem  116  and an inner surface  138  of valve cylinder  139 . Fluids, such as air and/or water, may not move proximally or distally past proximal rotation seal  140  or middle rotation seal  150 , between an outer surface of valve stem  116  and an inner surface  138  of valve cylinder  139 , except at notch  147 ,  151 , respectively. 
     Cap  118 , which may have any of the properties of cap  18 , may include a stationary portion  170  and a rotatable portion  172 . Although rotatable portion  172  is described herein as being separate from valve stem  116 , it will be appreciated that rotatable portion  172  could be formed integrally with valve stem  116 . Stationary portion  170  may remain stationary with respect to valve cylinder  139  when valve  100  is inserted in valve cylinder  139 . Stationary portion  170  may include an inner cylindrical member  174  and an outer cylindrical member  176 . As shown in  FIGS.  2 A- 2 B , inner cylindrical member  274  and outer cylindrical member  276  may be made from a single, unitary piece of material, which may facilitate manufacturing efficiencies. Alternatively, inner cylindrical member  274  and outer cylindrical member  276  may be two separate pieces that are assembled together. Outer cylindrical member  176  may include one or more mating features  178  for mating cap  118  with an outer portion of valve cylinder  139 . For example, mating feature  178  may be a protrusion extending radially inward that may mate with a corresponding groove or indentation of valve cylinder  139 . A distal surface of inner cylindrical member  174  may rest upon a proximal outer surface of valve cylinder  139 . A cross-section of inner cylindrical member  174  may be “L” shaped, forming a radially-outward directed flange, or seat, for a spring (to be described). 
     Rotatable portion  172  may be rotatable relative to valve cylinder  139  and/or stationary portion  170 . Although rotatable portion  172  is described separately from valve stem  116 , it will be understood that rotatable portion  172  and valve stem  116  could be formed of a single, integral structure. Rotatable portion  172  may be affixed to valve stem  116 , so that rotation of rotatable portion  172  also causes rotation of valve stem  116 . Rotatable portion  172  of cap  118  may have a button shape, a knob shape, or any other suitable shape. An exterior surface of rotatable portion  172  may have gripping surfaces to assist a user in gripping onto rotatable portion  172 . A rim  180  of rotatable portion  172  may extend in a longitudinal direction between outer cylindrical member  176  and inner cylindrical member  174 . Rotatable portion  172  may also be proximally and distally movable. Rotatable portion  172  may rotate while it is being translated proximally or distally. For example, a user could press down on rotatable portion  172 , which could engage a ramp or other surface and cause rotatable portion  172  to rotate as it translates proximally or distally. 
     Cap  118  may be fitted with a spring  182 , which may be a biasing member. Spring  182  may be a coil spring, leaf spring, or another type of resilient member, such as any member having shape-memory properties. Spring  182  may be, for example, a torsion spring. Alternatively, spring  182  may be a compression spring. Spring  182  may be configured in cap  118  so that, when spring  182  is in a relaxed state, valve  100  has a first configuration. When rotatable portion  172  is rotated (e.g., in a clockwise or counterclockwise direction) about a longitudinal axis of the valve, so that valve  100  has a second configuration, spring  182  may be in a deformed state and may store potential energy due to the deformation of spring  182 . Spring  182  may have properties, including a stiffness, such that spring  182  exerts a known return force on rotatable portion  172 , after it has been rotated from the first configuration to the second configuration. 
     A cap seal  190  may be disposed between rotatable portion  172  and stationary portion  170 . Cap seal  190  may have any of the properties of cap seal  90 . Alternatively, something other than a seal that provides a resistive or frictional force between movable portion  172  and stationary portion  170  may be used in place of cap seal  190 . For example, instead of cap seal  190 , portions of movable portion  172  or stationary portion  170  may be textured or may have structures or substances disposed thereon that increase resistance between them. Cap seal  190  may be, for example, an O-ring seal, a washer, or other shape and may be formed of elastomeric material. As shown in  FIGS.  2 A and  2 B , cap seal  190  may be fixed with respect to rotatable portion  172  in an annular groove within rotatable portion  172 , and cap seal  190  may be rotatable with respect to stationary portion  170 . Alternatively, cap seal  190  may be fixed with respect to stationary portion  170  and rotatable with respect to rotatable portion  172 . Cap seal  190  may provide a frictional force between an outer surface of cap seal  190  and an inner surface of stationary portion  170 . Thus, when valve  100  is in the second configuration, and spring  182  is in a deformed state, friction caused by cap seal  190  may resist a return force of spring  182  that urges valve  100  to the first configuration, in which spring  182  is relaxed. The relationship between a frictional force caused by cap seal  190  and a return force caused by spring  182  may be such that valve  100  automatically moves from the second configuration to the first configuration in a set, predetermined amount of time. In other words, the frictional force may delay the return of valve  100  to the first configuration. The delay may align with a time desired to flush an air channel of an endoscope, as discussed below. 
     A stem seal  191  may be disposed between valve stem  116  and inner surface  138  of valve cylinder  139 . Stem seal  191  may be, for example, an O-ring seal, a washer, or other type of structure and may be formed of elastomeric material. Stem seal  191  may be fixed to valve stem  116 . Stem seal  191  may be configured such that fluids (e.g., air or water) cannot pass proximally or distally of stem seal  191 . 
       FIG.  2 A  shows valve  100  positioned in valve cylinder  139  and in the first configuration described above. Spring  182  is in a relaxed, neutral state so that spring  182  does not exert a force to rotate rotatable portion  172  and valve stem  116 . 
     Proximal rotation seal  140  may be positioned so that hole  146  axially aligns with air outlet D but is angularly offset (relative to a longitudinal axis) from air outlet D. For example, hole  146  may be offset by 180 degrees or another angle (e.g., 90 degrees or 45 degrees) from air outlet D.  FIG.  2 A  shows hole  146  as being offset from air outlet D by 180 degrees. Similarly, distal rotation seal  142  may be positioned so that hole  148  axially aligns with water inlet A but is angularly offset (relative to a longitudinal axis) from water inlet A. For example, hole  148  may be offset by 180 degrees or another angle (e.g., 90 degrees or 45 degrees) from water inlet A.  FIG.  2 A  shows hole  148  as being offset from water inlet A by 180 degrees. Holes  146  and  148  may be offset from air outlet D and water inlet A, respectively, by the same angle (e.g., 180 degrees). 
     Proximal rotation seal  140  may further be positioned so that notch  147  is axially and radially aligned with air outlet D. Middle rotation seal  150  may also be positioned so that notch  151  is axially and radially aligned with air inlet C. 
     In the first configuration, water or other fluid from water inlet A may not pass proximally past distal rotation seal  142 . Thus, water or other fluid may not exit either water outlet B or air outlet D. Air or other fluid from inlet C may pass proximally and distally past middle rotation seal  150  because notch  151  is aligned with air inlet C. Thus, air or other fluid may move distally and exit through water outlet B. Air or other fluid may also pass proximally past proximal rotation seal  140  because notch  147  is aligned with air outlet D. Thus, in the first configuration, air or other fluid passes from air inlet C through both water outlet B and air outlet D. The first configuration may be used after flushing an air channel of an endoscope to ensure that water is removed from the air channel and the water channel before the scope is subject to further reprocessing. 
       FIG.  2 B  shows valve  100  in the second configuration, discussed above. To transition valve  100  from the first configuration to the second configuration, a user may rotate rotatable portion  172  of cap  118 . For example, as shown in  FIGS.  2 A- 2 B , rotatable portion  172  may be rotated by 180 degrees to transition valve  100  from the first configuration to the second configuration. Alternatively, rotatable portion  172  may be rotated by another amount, which may be equivalent to an offset of holes  146 ,  148  in the first configuration. In the second configuration, hole  146  of proximal rotation seal  140  may be axially and radially (angularly) aligned with air outlet D, and notch  147  may not be aligned with air outlet D. Similarly, hole  148  of distal rotation seal  142  may be axially and radially aligned with water inlet A. Middle rotation seal  150  may be rotated so that notch  151  no longer aligns with air inlet C. 
     In the second configuration, water or other fluid from water inlet A may pass through hole  148  and through distal opening  132  and into lumen  122 . Water or other fluid may travel proximally through lumen  122 , through proximal opening  130 , through hole  146 , and into air outlet D. Water or other fluid from water inlet A may not pass proximally past distal rotation seal  142 . Water or other fluid exiting hole  146  may not pass distally past proximal rotation seal  140 . Air or other fluid from air inlet C may not pass distally past middle rotation seal  150  because notch  151  is not aligned with air inlet C. Thus, in the second configuration, only water or other fluid may exit only through air outlet D to be flushed through an air channel of an endoscope and clear the air channel of debris following a procedure. 
     In the second configuration, if a user is not operating cap  118  of valve  100 , valve  100  may remain for a time in the second configuration due to an interaction between the spring  182  and the cap seal  190 . Over a period of time (e.g., a predetermined period of time), a restorative force of spring  182  may return valve  100  to the first configuration. For example, cap seal  190  may exert forces opposite forces exerted by spring  182 , thereby delaying relaxation of the spring  182  and return to the first configuration of the valve  100 . Valve  100  may progressively be returned to the first configuration (e.g., it may slowly move from the second configuration to the first configuration). Because the proximal rotation seal  140  and the distal rotation seal  142  may each have a recessed notch (such as notch  212 ) adjacent to holes  146  and  148 , respectively, water or other fluid may continue to flow through holes  146  and  148  even after hole  146  is no longer directly aligned with air outlet D and hole  148  is no longer directly aligned with water inlet A. For example, the notches may extend around a portion of a circumference of proximal rotation seal  140  and/or distal rotation seal  142  so that, as rotation seal  140  or  142  rotates along with valve stem  116 , the notch may continue to be adjacent to air outlet D or water inlet A. Water or other fluid may flow from water inlet A, into the notch of distal rotation seal  142 , into hole  146 , through distal opening  132 , through lumen  122 , through proximal opening  130 , out of hole  148 , through the notch of proximal rotation seal  140 , and into water outlet D. Water or other fluid may cease to flow when the notches of proximal rotation seal  140  and/or distal rotation seal  142  are no longer in communication with air outlet D and/or water inlet A, respectively. Thus, valve  100  may deliver water to air outlet D for a predetermined amount of time, which may be specified by a cleaning protocol. For example, cap seal  190  and spring  182  may be calibrated so as to flush an air channel for a particular, predetermined amount of time 
     An exemplary method for using valve  100  is provided herein. Following a procedure with an endoscope, the endoscope may be removed from a patient. In order to prepare the endoscope for reprocessing, an air/water valve may be removed from valve cylinder  139 . Valve  100  may then be inserted into valve cylinder  139  while valve  100  is in the first configuration. In the first configuration, as discussed above, neither air nor water may be flushed through any channel of the endoscope. A user may rotate rotatable portion  172  of cap  118  to transition valve  100  to the second configuration. The user may then release rotatable portion  172  of cap  118  and may attend to other aspects of a post-operative procedure. Even after rotatable portion  172  is released, water or other fluid may continue to flow for a predetermined time from water inlet A and out of air outlet D, through the air channel of the endoscope. After valve  100  has flushed water or other fluid through the air channel for the predetermined amount of time, the valve  100  may be removed from valve cylinder  139  and may optionally be disposed. 
     While principles of the present disclosure are described herein with reference to illustrative examples for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and substitution of equivalents all fall within the scope of the examples described herein. Accordingly, the invention is not to be considered as limited by the foregoing description.