Patent Description:
The claimed invention relates generally to devices for delivering agents. More specifically, aspects of the claimed invention relate to devices for delivery of powdered agents, such as hemostatic agents.

In certain medical procedures, it may be necessary to stop or minimize bleeding internal to the body. For example, an endoscopic medical procedure may require hemostasis of bleeding tissue within the gastrointestinal tract, for example in the esophagus, stomach, or intestines.

During an endoscopic procedure, a user inserts a sheath of an endoscope into a body lumen of a patient. The user utilizes a handle of the endoscope to control the endoscope during the procedure. Tools are passed through a working channel of the endoscope via, for example, a port in the handle, to deliver treatment at the procedure site near a distal end of the endoscope. The procedure site is remote from the operator.

To achieve hemostasis at the remote site, a hemostatic agent may be delivered by a device inserted into the working channel of the endoscope. Agent delivery may be achieved through mechanical systems, for example. Such systems, however, may require numerous steps or actuations to achieve delivery, may not achieve a desired rate of agent delivery or a desired dosage of agent, may result in the agent clogging portions of the delivery device, may result in inconsistent dosing of agent, or may not result in the agent reaching the treatment site deep within the GI tract.

<CIT> discloses an apparatus for delivering a powdered agent into a subject's body, which may include a first passage for receiving a pressurized gas. The apparatus also may include a container housing a powdered agent. The container may be in fluid connection with the first passage. At least a portion of the pressurized gas is introduced into the powdered agent in the container to fluidize the powdered agent. The apparatus also may include a second passage for receiving the powdered agent from the container. In a first configuration of the apparatus, the second passage may not be in fluid connection with the container. In a second configuration of the apparatus, the second passage may be in fluid connection with the container. The apparatus may be configured to transition between the first configuration and the second configuration.

The current disclosure may solve one or more of these issues or other issues in the art.

The claimed invention comprises a device for delivering an agent, as defined by the appended independent claim <NUM>, and a system for delivering an agent which includes such a claimed device, as defined by the appended independent claim <NUM>. Further embodiments of the claimed invention are described in the appended dependent claims.

Any aspect, embodiment, or example described in the following and not falling within the scope of the claimed invention thus defined is to be considered background information, which is provided to facilitate the understanding of the claimed invention.

Each of the aspects disclosed herein may include one or more of the features described in connection with any of the other disclosed aspects.

Disclosed is a device for delivering an agent which may comprise a source of agent; a mixing chamber for receiving fluid and the agent; an outlet in fluid communication with the mixing chamber to deliver the fluid and the agent; and an actuator configured to (<NUM>) deliver a first flow of the fluid substantially free from the agent through the outlet; (<NUM>) after delivering the first flow, deliver a second flow of the fluid and the agent through the outlet; and (<NUM>) after delivering the second flow, deliver a third flow of the fluid substantially free from the agent through the outlet.

The actuator may transition from a first configuration to a second configuration. In the first configuration, the source of agent may not be in fluid communication with the mixing chamber. In the second configuration, the source of agent may not be in fluid communication with the mixing chamber. The actuator may include a valve defining an opening. In the first configuration, the opening may not be in fluid communication with the source of agent. In the second configuration, the opening may not be in fluid communication with the source of agent. The valve may include a first portion and a second portion. A spring may connect the first portion to the second portion. The valve may be able to transition from the first configuration to the second configuration only when a flow of the fluid is flowing through the mixing chamber. The actuator may include a body pivotable via at least one of a piston or a wire. The actuator may include a first rigid member and a second rigid member. The first rigid member may be pivotably coupled to the second rigid member. The second rigid member may include a trigger. The actuator may include a rotatable member having at least one blade extending from the rotatable member. The actuator may further include a gear. The actuator may include a first actuator for controlling a flow of the agent from the source of agent and a second actuator for controlling a flow of the fluid. The first actuator and the second actuator may be configured to be independently activated. The first actuator may be activated only if the second actuator is activated. The actuator may include a spring and a button valve. The actuator may include a first portion; a second portion defining an opening; and a spring extending from the first portion to the second portion. In the first configuration and the third configuration, the opening may not be in fluid communication with the source of agent. In the second configuration, the opening may not be in fluid communication with the source of agent. The agent may include a powder. The actuator may define an opening. In the first configuration and the third configuration, the opening may not be in fluid communication with the source of agent. In the second configuration, the opening may be in fluid communication with the source of agent such that the powder can pass through the opening.

Further disclosed is a device for delivering an agent, which may comprise: a source of fluid; a source of powderized agent; a mixing chamber for receiving the fluid and the powderized agent; and an actuator configured to transition from a first configuration to a second configuration. In the first configuration, the source of agent may not be in fluid communication with the mixing chamber and a first flow of fluid substantially free from agent is received in the mixing chamber. In the second configuration, the source of agent may be in fluid communication with the mixing chamber and the powderized agent and a second flow of fluid are received in the mixing chamber.

The actuator may be further configured to transition from the second configuration to the first configuration after transitioning from the first configuration to the second configuration.

Also disclosed, but not part of the claimed invention, is a method of delivering an agent, which may comprise: activating an actuator to cause: delivering a first flow of fluid, wherein the fluid is substantially free from a agent; after delivering the first flow, delivering a second flow of the fluid combined with the agent; and after delivering the second flow, delivering a third flow of fluid, wherein the fluid is substantially free from agent.

The agent may include a hemostatic agent. The fluid may be a pressurized fluid. During the delivering of the first flow and the third flow, an opening of the actuator may not be in fluid communication with a source of the agent. During the delivering of the second flow, an opening of the actuator may be in fluid communication with the source of the agent.

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 claimed invention, which is defined by the appended set of claims. 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. " The term "distal" refers to a direction away from an operator, and the term "proximal" refers to a direction toward an operator. The term "approximately," or like terms (e.g., "substantially"), includes values +/- <NUM>% of a stated value.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects of the disclosure and together with the description, serve to explain the principles of the disclosure.

A dual-stage actuation mechanism may be used to deliver an agent (e.g., a powdered agent) from a delivery system to a site of a medical procedure. The actuation mechanism may function to, upon activation, first deliver a flow of fluid, without the agent, through the delivery system and to the site. Then, a combined flow of the fluid and the agent may be delivered. Following delivery of a desired amount of the agent, the fluid may again be delivered without the agent. Delivery of fluid alone, before and after delivery of the agent, may facilitate flushing of components of the delivery system and may prevent clogging of the delivery system.

<FIG> shows a delivery system <NUM>, which may be a powder delivery system. Delivery system <NUM> includes a body <NUM>. Body <NUM> may have a variety of features, to be discussed in further detail herein. The features described herein may be used alone or in combination and are not mutually exclusive. Like reference numbers and/or terminology are used to denote similar structures, when possible.

<FIG> shows a cross-section of an exemplary body <NUM>, which may be a component of delivery system <NUM>. Body <NUM> may include or may be configured to receive an enclosure <NUM> (or other source) storing an agent <NUM>. Enclosure <NUM> may be screwed onto body <NUM> for providing agent <NUM> to body <NUM>, or a lid/store of agent <NUM> may be screwed onto enclosure <NUM> for supplying agent <NUM> to enclosure <NUM>. Agent <NUM> may be, for example, a powdered agent, such as a hemostatic agent. Agent <NUM> may alternatively be another type of agent or form of agent (e.g., a liquid or gel agent) and may have any desired function. Enclosure <NUM> may be removably attached to other components of delivery system <NUM>, including components of body <NUM>. Body <NUM> has an agent inlet <NUM> in fluid communication with enclosure <NUM> for receiving agent <NUM> from enclosure <NUM>. Body <NUM> includes a fluid inlet <NUM> for receiving fluid, such as pressurized fluid, from a source <NUM> (e.g., a disposable canister, a tank, a supply line, etc.).

Body <NUM> may include a nozzle <NUM>, shown separately in <FIG>. Nozzle <NUM> may include a nozzle chamber <NUM>, which may be in fluid communication with source <NUM>. Nozzle chamber <NUM> may terminate in an opening <NUM>. A diameter of nozzle opening <NUM> may be between <NUM> and <NUM> (between <NUM> and <NUM> inches) (e.g., <NUM> (<NUM> inches)). Opening <NUM> may be positioned approximately along a longitudinal axis of agent inlet <NUM>. Opening <NUM> may be positioned behind, slightly behind, slightly in front of, or directly in front of agent inlet <NUM>.

Opening <NUM> may be in fluid communication with a mixing body <NUM> defining a mixing chamber <NUM> for combining agent <NUM> with fluid from source <NUM>. Nozzle <NUM> may connect with mixing body <NUM> of body <NUM> via any suitable fastening method (e.g., nuts, bolts, being formed of a continuous material with mixing body <NUM>, etc.) An O-ring 29a may sit in an annular seat 29b of nozzle <NUM> so as to provide a seal between nozzle <NUM> and mixing body <NUM>. Mixing body <NUM> may connect with enclosure <NUM> via any suitable fastening method (such as screwing onto mixing body <NUM>, as shown) and may also include seals <NUM>, <NUM> to provide seals between enclosure <NUM> and mixing body <NUM> or other portions of body <NUM>.

A combination of agent <NUM> and fluid is delivered from outlet <NUM> of body <NUM>. Outlet <NUM> may be in fluid communication with a catheter <NUM> (see <FIG>) or other component for delivering the combination of agent <NUM> and fluid to a desired location within a body lumen of a patient. Mixing chamber <NUM> is in fluid communication with outlet <NUM> and mixing chamber <NUM> and/or outlet <NUM> may be configured to allow for fluid connection with catheter <NUM>. A diameter/width of outlet <NUM> may be the same as or approximately the same as a diameter/width of catheter <NUM> or an internal lumen of catheter <NUM>. A lack of edges formed between mixing body <NUM> (including mixing chamber <NUM> and outlet <NUM>) may reduce clogging of agent passing into catheter <NUM>. A catheter may have an inner diameter of <NUM> (<NUM> inches), <NUM> (<NUM> inches), or <NUM> (<NUM> inches), for example, and mixing chamber <NUM>, outlet <NUM>, and or/mixing body <NUM> may be dimensioned for compatibility with those sizes of catheter.

Delivery system <NUM> includes an actuation mechanism <NUM> for controlling a release of agent <NUM> and/or fluid via outlet <NUM>. For example, actuation mechanism <NUM> may include a trigger, button, slider, knob, lever, or other suitable mechanism. Actuation mechanism causes agent <NUM> and/or fluid to enter mixing chamber <NUM>, where agent <NUM> and fluid are combined. In principle, delivery system <NUM> could include more than one actuation mechanism <NUM>; for example, multiple actuation mechanisms <NUM> could be used to separately control a flow of fluid through fluid inlet <NUM> and a flow of agent from enclosure <NUM> through agent inlet <NUM>. According to the claimed invention, actuator <NUM> is operatively connected to valve <NUM> for controlling a flow of the fluid through the fluid inlet <NUM> and a flow of the agent through the agent inlet <NUM>.

<FIG> show cross-sectional views of an embodiment of a body, which may be a component of delivery system <NUM>. Body <NUM> includes an agent inlet <NUM> in fluid communication with enclosure <NUM> storing an agent <NUM>. Agent inlet <NUM> may be appropriately sized so as to allow passage of agent <NUM> therethrough. Agent inlet <NUM> may have approximately the same size as opening <NUM>, described below. Agent inlet <NUM> may be an opening formed in body <NUM>. Agent inlet <NUM> may be a portion of enclosure <NUM>, particularly where enclosure <NUM> is not detachable from body <NUM>. Alternatively, enclosure <NUM> may include an opening formed therein, which may be in fluid communication with agent inlet <NUM>. Body <NUM> also includes a fluid inlet <NUM> for receiving fluid from source <NUM> (see <FIG>). The arrow in <FIG> shows the direction of fluid flow into inlet <NUM>. Body <NUM> also includes a valve <NUM> for controlling flow of fluid through fluid inlet <NUM> and agent <NUM> through agent inlet <NUM>. Valve <NUM> is operatively connected to actuation mechanism <NUM> (see <FIG>).

Valve <NUM> may include a first portion <NUM>. First portion <NUM> may have a first seal <NUM> and a second seal <NUM> received thereon. First seal <NUM> and/or second seal <NUM> may be, for example, O-ring seals. First portion <NUM> may also include a neck portion <NUM>, between first seal <NUM> and second seal <NUM>. Neck portion <NUM> may have a smaller cross-sectional diameter than other portions of first portion <NUM> (e.g., those receiving first seal <NUM> and second seal <NUM>).

Valve <NUM> may also include a second portion <NUM>. Second portion <NUM> may define an opening <NUM>. Opening <NUM> may extend through an entire thickness of second portion <NUM> in a direction parallel to longitudinal axis of agent inlet <NUM> (but not through an entire width of second portion <NUM>). Second portion <NUM> may have a third seal <NUM>, fourth seal <NUM>, and fifth seal <NUM> received thereupon. Third seal <NUM> may be on a first side of opening <NUM>, more proximate to first portion <NUM>. Fourth seal <NUM> may be on a second, opposite side of opening <NUM>. Fifth seal <NUM> also may be on the second side of opening <NUM>. First portion <NUM> may be closer to fourth seal <NUM> than to fifth seal <NUM>.

A first spring <NUM> may extend between and connect first portion <NUM> and second portion <NUM>. First spring <NUM> may be fixedly connected to an end <NUM> of first portion <NUM> and to an end <NUM> of second portion <NUM>. First portion <NUM> may taper to first end <NUM>, which may have a smaller cross-sectional diameter than other portions of first portion <NUM>. Second portion <NUM> may taper to first end <NUM>, which may have a smaller cross-sectional diameter than other portions of second portion <NUM>. First end <NUM> may be an end of second portion <NUM> that is closest to third seal <NUM>. A second spring <NUM> may extend from a second end <NUM> of second portion <NUM>. Second end <NUM> may be an end of second portion <NUM> that is closest to fifth seal <NUM>. First spring <NUM> may have a smaller spring constant than second spring <NUM> (i.e., first spring <NUM> may be a weaker spring than second spring <NUM>). An equivalent force on first spring <NUM> and second spring <NUM> may cause first spring <NUM> to compress more than second spring <NUM>.

Valve <NUM> may be received within a cavity <NUM> of body <NUM>. Cavity <NUM> may be defined by surface(s) <NUM>. First cavity <NUM> may have a first opening <NUM>, which is at one end of cavity <NUM>. Cavity <NUM> may have a second opening <NUM>, which is in fluid communication with fluid inlet <NUM> and source <NUM>. A third opening <NUM> of cavity <NUM> may be in fluid communication with a fluid nozzle chamber <NUM>. A fourth opening <NUM> of cavity <NUM> may be in fluid communication with a mixing chamber <NUM>, which may have any of the features of mixing chamber <NUM>. Fourth opening <NUM> may be aligned or approximately aligned with agent inlet <NUM> so as to be in selective fluid communication with agent inlet <NUM>. Second spring <NUM> may contact surface <NUM> at an end <NUM> of cavity <NUM> that is opposite from the end of cavity <NUM> having first opening <NUM>.

Seals <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may have dimensions and measurements on a durometer such that they form seals with surface(s) <NUM> of cavity <NUM>. Seals <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may also permit sliding movement of valve <NUM> within cavity <NUM>.

<FIG> shows body <NUM> in a first configuration, in which agent <NUM> is not permitted to flow into cavity <NUM> via agent inlet <NUM>, and fluid is not permitted to flow into cavity <NUM> via fluid inlet <NUM>. Fourth seal <NUM> and fifth seal <NUM> may be positioned on either side of agent inlet <NUM> so that agent <NUM> may not pass between seals <NUM>, <NUM> and surface(s) <NUM>, thus preventing flow of agent <NUM>. First seal <NUM> and second seal <NUM> may be positioned on either side of fluid inlet <NUM>. Seals <NUM>, <NUM>, may prevent movement of fluid from fluid inlet <NUM> between seals <NUM>, <NUM> and surface(s) <NUM>. In the first configuration, springs <NUM>, <NUM> may be in relaxed, uncompressed states.

<FIG> shows body <NUM> in a second configuration, in which fluid is permitted to flow into cavity <NUM> via fluid inlet <NUM>. In operation, when actuation mechanism <NUM> is activated, first portion <NUM> of valve138 may translate within cavity <NUM>, in a first direction toward end <NUM> of cavity <NUM>. Actuation mechanism <NUM> may be a separate component, or a surface of valve <NUM> may serve as an actuation mechanism and may receive a force from a user's hand. First portion <NUM> may exert a force first against spring <NUM>, causing first spring <NUM> to compress. Because first spring <NUM> is weaker than second spring <NUM> and/or because second portion <NUM> may not move until first spring <NUM> is compressed a selected amount, second portion <NUM> may not immediately move along with first portion <NUM>.

As shown in <FIG>, in the second configuration, an entirety of second seal <NUM> may not be in contact with surface(s) <NUM>. For example, second seal <NUM> may be aligned with a portion of third opening <NUM>. Thus, fluid from fluid inlet <NUM> may pass between first portion <NUM> and surface(s) <NUM> (e.g., along neck portion <NUM>). The fluid may then pass through third opening <NUM> into fluid nozzle chamber <NUM>. The fluid may then pass through a fluid nozzle opening <NUM>, into mixing chamber <NUM>. The fluid may then exit through outlet <NUM>.

In the second configuration of <FIG>, second portion <NUM> may remain in the same position or in approximately the same position as in the first configuration (<FIG>). Therefore, for the reasons discussed above, agent <NUM> may not be permitted to flow into cavity <NUM> via agent inlet <NUM>. As a result, only the fluid from source <NUM> may exit outlet <NUM>.

As actuation mechanism <NUM> continues to be activated, second portion <NUM> may begin to move in the first direction (to the left in the Figures), after first spring <NUM> has been sufficiently compressed, when the force is sufficient to compress second spring <NUM>. Valve <NUM> may be thusly transitioned from the second configuration (<FIG>) to a third configuration of <FIG>. In the third configuration, third seal <NUM> and fourth seal <NUM> may be disposed on opposite sides of agent inlet <NUM>, and opening <NUM> of second portion <NUM> may be aligned with agent inlet <NUM> so as to be in fluid communication with agent inlet <NUM>. Therefore, agent <NUM> may be permitted to pass into opening <NUM>, via agent inlet <NUM>. Agent may be unable to pass between third and fourth seals <NUM>, <NUM> and surface(s) <NUM>, maintaining agent <NUM> in a desired location so that it will pass through opening <NUM>.

Meanwhile, first portion <NUM> may remain in the same position or in approximately the same position as in the second configuration (<FIG>). Therefore, fluid from source <NUM> may continue to flow as described above, with respect to <FIG>. Second spring <NUM> and/or actuation mechanism <NUM> may be configured so that, after second spring <NUM> is compressed by a specified amount, neither of first portion <NUM> nor second portion <NUM> may move further in the first direction, to maintain the third configuration of <FIG>. In the third configuration, second spring <NUM> may be fully compressed or may be only partially compressed.

After agent <NUM> passes through opening <NUM>, agent <NUM> may pass through fourth opening <NUM>, into mixing chamber <NUM>. There, agent <NUM> may combine with fluid from source <NUM>. The combined agent <NUM> and fluid from fluid source <NUM> may then pass through outlet <NUM>, to be delivered to a desired location.

After actuation mechanism <NUM> is no longer activated, a restoring force of second spring <NUM> may return valve <NUM> to the second configuration, in which fluid from source <NUM> is delivered, but agent <NUM> is not delivered. Then, a restoring force of first spring <NUM> may return valve <NUM> to the first configuration, in which neither of fluid from source <NUM> nor agent <NUM> is delivered.

It will be appreciated, although the above description describes the second configuration (<FIG>) as resulting from compression of first spring <NUM> without compression of second spring <NUM>, that both first and second springs <NUM>, <NUM> may be compressed in the second configuration so as to align seals <NUM>, <NUM>, <NUM>, <NUM>, <NUM> as described above to allow delivery of only fluid from source <NUM>. Furthermore, in transitioning from the second configuration (<FIG>) to the third configuration (<FIG>), first spring <NUM> may experience further compression (first spring <NUM> may not be fully compressed in the second configuration).

Furthermore, it will be appreciated that there are numerous configurations of valve <NUM> in between the first and second configurations and in between the second and third configurations, For example, configurations may exist in which a portion of agent inlet <NUM> is covered and a portion of agent inlet <NUM> is aligned with opening <NUM> so that opening <NUM> is in fluid communication with agent inlet <NUM>. In such a configuration, a relatively smaller amount of agent <NUM> may be permitted to pass through opening <NUM>, compared with the third configuration (<FIG>). As valve <NUM> transitions between the second configuration (<FIG>) and the third configuration (<FIG>), an increasing amount of agent inlet <NUM> may align with opening <NUM>, allowing an increasing amount of agent <NUM> to pass into opening <NUM>.

Body <NUM> may facilitate delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> through outlet <NUM> before delivery of agent <NUM> and after delivery of agent <NUM>. This delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> may flush system <NUM>, reducing or eliminating clogging.

<FIG> show an exemplary metering mechanism <NUM>, which may be used as a portion of delivery system <NUM>. <FIG> both show views with enclosure <NUM> removed, looking in a direction toward agent inlet <NUM> and body <NUM> (i.e., enclosure <NUM> would be coming out of the top of the page of <FIG>).

As shown in <FIG>, metering mechanism <NUM> may include a door <NUM>, which may pivot about a fixed pivot point A, and which may be a knife-edge door that has a very thin thickness in a direction parallel to a longitudinal axis of agent inlet <NUM>. As shown in <FIG>, door <NUM> may have a shape that includes any combination of straight and rounded sides. For example, door <NUM> may have three straight sides and one rounded side. Pivot point A may be located between one of the straight sides and the rounded side.

Metering mechanism <NUM> may also include a piston <NUM>. Piston <NUM> may be disposed partially within a chamber <NUM>, and a stem <NUM> of piston <NUM> may extend through an opening <NUM> in a wall of chamber <NUM>. A spring <NUM> may also be disposed within chamber <NUM>. Stem <NUM> of piston <NUM> may extend along a central axis of spring <NUM>.

Chamber <NUM> may be fluidly connected to a source of fluid, such as source <NUM>. When the fluid <NUM> enters chamber <NUM>, chamber <NUM> may be pressurized, and the fluid may exert a force on a head <NUM> of piston <NUM>, in a first direction toward opening <NUM>. The force from the fluid may cause piston <NUM> to move in the first direction. A seal (not shown) may be disposed between chamber <NUM> and one or both of stem <NUM> and head <NUM>, so that the fluid may not exit chamber <NUM>. As piston <NUM> moves in the first direction (to the left in <FIG>), piston <NUM> may compress spring <NUM>, generating a restorative force in a second direction, opposite the first direction. A movement of piston <NUM> in the first direction may stop when any of the following occurs (<NUM>) head <NUM> presses against surfaces of chamber <NUM>; (<NUM>) a restorative force of spring <NUM> is equal to a force of the fluid on piston <NUM>; and/or (c) spring <NUM> is fully compressed.

In a first configuration of metering mechanism <NUM>, shown in <FIG>, spring <NUM> may be in a relaxed state (such as when no fluid is supplied to chamber <NUM>). Door <NUM> may be in a first position. <FIG> shows a second configuration of metering mechanism <NUM>, in which spring <NUM> is compressed, and piston <NUM> has moved in the first direction (due to fluid supplied to chamber <NUM>). Door <NUM> may be in a second position.

When a user activates actuation mechanism <NUM>, fluid (e.g., from source <NUM>) may flow into chamber <NUM>. Piston <NUM> and door <NUM> may be configured such that, when fluid is supplied to chamber <NUM>, as piston <NUM> moves in the first direction, piston <NUM> exerts a force on door <NUM> in the first direction. The force of piston <NUM> may cause door <NUM> to rotate about pivot point A. As door <NUM> rotates, it may expose an opening <NUM>, which may be in fluid communication with a chamber (not shown) of body <NUM>. At first, after piston <NUM> begins moving in the first direction, only a portion of opening <NUM> may be exposed due to rotation of door <NUM>. As piston <NUM> continues to move in the first direction, door <NUM> may continue to rotate, and more of opening <NUM> may be exposed. When piston <NUM> is fully extended (<FIG>), an entirety of opening <NUM> may be exposed. In the first position of door <NUM> (<FIG>), door <NUM> covers opening <NUM>, so that opening <NUM> does not communicate with enclosure <NUM>, and no agent <NUM> can pass into opening <NUM>.

When actuation mechanism <NUM> is no longer activated, pressure may be released from chamber <NUM> (via, e.g., a release valve, which is not shown). Spring <NUM> may urge head <NUM> of piston <NUM> in the second direction, away from the opening <NUM>, due to the restoring force of spring <NUM>. Thus, piston <NUM> may no longer exert a force on door <NUM>. The restoring force of spring <NUM> may cause piston <NUM> to return to the first configuration (<FIG>). Door <NUM> may also be biased to return to the first configuration (<FIG>). For example, door <NUM> may be spring biased at, e.g., at pivot point A.

In use, when actuation mechanism <NUM> is activated, such activation may cause fluid to pass through fluid inlet <NUM> and out of outlet <NUM>. Meanwhile, as described above, actuation mechanism <NUM> may begin to expose opening <NUM>. A portion of opening <NUM> may not immediately be exposed due to a delay in pressurizing chamber <NUM>, or a delay in exposing opening <NUM> once chamber <NUM> is pressurized. Additionally or alternatively, a size of a portion of opening <NUM> that is exposed may initially be sized such that agent <NUM> does not flow through opening <NUM>, or only a small amount of agent flows through opening <NUM>. Thus, initially after actuation mechanism is activated, only fluid from source <NUM> may initially flow from outlet <NUM>, without any agent <NUM>.

Similarly, fluid may continue to be delivered via outlet <NUM>, after actuation mechanism <NUM> begins or finishes transitioning from the second configuration (<FIG>) to the first configuration (<FIG>). For example, actuation mechanism <NUM> may be configured so that chamber <NUM> is depressurized before fluid stops passing through fluid inlet <NUM>. Opening <NUM> may be covered partially or entirely by door <NUM>, while fluid continues to pass through fluid inlet <NUM>.

Metering mechanism <NUM> may facilitate delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> through outlet <NUM> before delivery of agent <NUM> and after delivery of agent <NUM>. This delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> may flush system <NUM>, reducing or eliminating clogging.

<FIG> show cross-sectional views of an exemplary body <NUM> for use with delivery system <NUM>. Body <NUM> may include an agent inlet <NUM>, which may be in fluid communication with enclosure <NUM> storing an agent <NUM>. Body <NUM> also may include a fluid inlet <NUM> for receiving fluid from source <NUM> (see <FIG>). Body <NUM> may also include a metering mechanism <NUM> for controlling flow of fluid through fluid inlet <NUM> and agent <NUM> through agent inlet <NUM>. Metering mechanism <NUM> may have any of the features of metering mechanism <NUM>.

Metering mechanism <NUM> may include a door <NUM>, which may have any of the properties of door <NUM>. Door <NUM> may be configured to rotate about a hinge B. Door <NUM> may also be operatively connected to a wire <NUM>. For example, a portion of door <NUM> that is on an opposite side of door <NUM> from hinge B may be operatively connected to wire <NUM>. A first end <NUM> of wire <NUM> may be attached to a ridge <NUM> extending from an edge of door <NUM> in a direction parallel to a longitudinal axis of agent inlet <NUM>.

A second end <NUM> of wire <NUM> may be operatively connected to a valve <NUM>. Valve <NUM> may be operatively connected to an actuation mechanism <NUM> or may include a surface which serves as an actuation mechanism <NUM> by receiving contact from a finger of a user. Valve <NUM> may be received within a fluid channel <NUM>, which may be in fluid connection with fluid inlet <NUM> and a fluid nozzle chamber <NUM>. A longitudinal axis of valve <NUM> may be approximately perpendicular to a longitudinal axis of fluid channel <NUM>. Valve <NUM> may also be received within a valve channel <NUM>, which may have a longitudinal axis that is approximately parallel to a longitudinal axis of valve <NUM>. Valve <NUM> may include first, second and third seals <NUM>, <NUM>, <NUM>, which may be, for example, O-ring seals. Seals <NUM>, <NUM>, <NUM> may prevent air from entering valve channel <NUM> from fluid channel <NUM>. Valve <NUM> may be dimensioned and formed of a material such that, in the configuration of <FIG>, valve <NUM> blocks fluid channel <NUM>, such that fluid from fluid inlet <NUM> may not pass valve <NUM> to enter fluid nozzle chamber <NUM>. For example, valve channel <NUM> may have a larger cross-sectional area than a cross-sectional area of fluid channel <NUM>, and valve <NUM> may occupy an entirety or approximately an entirety of valve <NUM>.

Door <NUM> may be biased such that, when no force is exerted on door <NUM> from wire <NUM> and door <NUM> is in a relaxed configuration, door <NUM> is approximately perpendicular or otherwise transverse to a central longitudinal axis of agent inlet <NUM>, such that agent <NUM> may not pass door <NUM> to pass through fluid inlet <NUM>. For example, door <NUM> may be spring-biased at pivot point B. <FIG> shows a first configuration of body <NUM>, in which door <NUM> is in a relaxed configuration, effectively closing agent inlet <NUM> so that agent inlet <NUM> is not in communication with a mixing chamber <NUM>.

Valve <NUM> may be movable in first and second directions, perpendicular to a longitudinal axis of fluid channel <NUM> and parallel to a longitudinal axis of valve channel <NUM>. As valve <NUM> moves in the first direction, narrowed portions <NUM> of valve <NUM> may move such that they are disposed within fluid channel <NUM>, and fluid may move past valve <NUM>. The narrowed portions may have a cross-sectional area that is smaller than that of fluid channel <NUM>, so that fluid may pass valve <NUM>. Therefore, movement of valve <NUM> in the first direction may activate flow of fluid from fluid inlet <NUM> into fluid nozzle chamber <NUM>.

Movement of valve <NUM> in the first direction may compress a spring <NUM>. When spring <NUM> is in a neutral, relaxed configuration, door <NUM> may also in its relaxed configuration (the configuration to which door <NUM> is biased), so that agent <NUM> may not flow past door <NUM> into agent inlet <NUM>.

As valve <NUM> moves in the first direction, valve <NUM> may move second end <NUM> of wire <NUM> in the first direction (to the right in <FIG>). As a result, first end <NUM> of wire <NUM> may move in the first direction. Alternatively, first end <NUM> of wire <NUM> may move in another direction such that a force from first end <NUM> of wire <NUM> causes door <NUM> to pivot about hinge B. Wire <NUM> may be routed over a pulley <NUM>, to accommodate space for other components of body <NUM> and/or delivery system <NUM>.

When first end <NUM> of wire <NUM> moves in the first direction, it may exert a force on ridge <NUM> in the first direction, which may cause door <NUM> to pivot such that an angle between door <NUM> and fluid inlet <NUM> increases (gets closer to <NUM> degrees) as door <NUM> pivots. As door <NUM> pivots, agent <NUM> may begin to flow past agent inlet <NUM> and door <NUM>. Valve <NUM> and/or door <NUM> may stop moving when any one or more of the following occurs: door <NUM> contacts a surface defining agent inlet <NUM> or other structure of body <NUM>, spring <NUM> reaches a maximum compression against a surface of valve channel <NUM>, or a surface of valve <NUM> reaches a stop (not shown). <FIG> shows body <NUM> in a second configuration, in which door <NUM> is fully open.

Upon initial activation of actuation mechanism <NUM>, door <NUM> may gradually pull away from agent inlet <NUM>, yet fluid may flow through a fluid nozzle chamber <NUM>, into a mixing chamber <NUM>, and out of outlet <NUM>, before any agent <NUM> or an appreciable amount of agent <NUM> is able to enter mixing chamber <NUM>. Opening of door <NUM> may occur after valve <NUM> permits flow of fluid from fluid inlet <NUM>. Once door <NUM> is opened a sufficient amount upon further activation of actuation mechanism <NUM>, agent <NUM> may enter mixing chamber <NUM> to be mixed with fluid and to be delivered out of outlet <NUM>. After actuation mechanism <NUM> is deactivated, door <NUM> may begin to return to its unbiased position. Closing of agent inlet <NUM> may allow a flow of fluid out of outlet <NUM> without any or an appreciable amount of agent <NUM> entering a mixing chamber <NUM>. A flow of fluid without agent <NUM>, or appreciable amounts of agent <NUM>, before and after a flow of fluid combined with agent <NUM> may lessen clogging of portions of system <NUM>.

Alternatively, other portions of body <NUM> may facilitate a flow of fluid without agent <NUM> before and after a flow of fluid combined with agent <NUM>. For example, properties of spring <NUM> and/or slack in wire <NUM> may delay opening of door <NUM>, and/or actuation mechanism <NUM> may be configured to permit a flow of fluid before movement of valve <NUM> in the first direction commences and after valve <NUM> returns to its unbiased configuration following delivery of agent <NUM> (<FIG>). Body <NUM> may facilitate delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> through outlet <NUM> before delivery of agent <NUM> and after delivery of agent <NUM>. This delivery of fluid from source <NUM> that is free from or substantially free from agent <NUM> may flush system <NUM>, reducing or eliminating clogging.

<FIG> show cross-sectional views of an exemplary body <NUM>, which may be a portion of delivery system <NUM>. Body <NUM> may include a metering mechanism <NUM>. Metering mechanism <NUM> may include a slider <NUM> (a first rigid member), which may be made from any suitable material (e.g., plastic, metal, composites, polymers, etc.) Slider <NUM> may be made of rigid or substantially rigid material. Slider <NUM> may include an opening <NUM> formed therein. Slider <NUM> may be configured to translate or slide in first and second directions relative to a remainder of body <NUM>. A longitudinal axis of slider <NUM> may be transverse (e.g., perpendicular) to a longitudinal axis of an agent inlet <NUM>, and movement of slider <NUM> may be axial along the longitudinal axis of slider <NUM>.

Slider <NUM> may be pivotably coupled to an arm <NUM> (a second rigid member) via, e.g., a hinge <NUM>. Slider <NUM> may be received within a channel (not shown) or otherwise constrained so that slider <NUM> may only translate along the first and second directions (i.e., axial movement). Hinge <NUM> may be similarly translatable within that channel. Arm <NUM> may be rotatable about an axis C, extending into and out of the page as shown in <FIG>. Axis C is also shown in <FIG> relative to arm <NUM>. Arm <NUM> may include a trigger <NUM> at one end of arm <NUM>. Trigger <NUM> may be contacted by a user in order to rotate arm <NUM> about axis C and thereby translate slider <NUM>. Arm <NUM> may have an approximately rectangular shape, as shown in <FIG>. An opening <NUM> in arm <NUM> may receive components of body <NUM> (e.g., a fluid nozzle chamber <NUM>). A top bar 438a of arm <NUM> may connect to slider <NUM> at hinge <NUM>.

As trigger <NUM> is depressed, trigger <NUM> may compress a spring <NUM>. Spring <NUM> may be operatively coupled to a button valve <NUM>. Button valve <NUM> may be operative to allow and disallow flow from source <NUM> through a fluid inlet <NUM>.

A first configuration of metering mechanism <NUM> is shown in <FIG>. In the configuration of <FIG>, spring <NUM> may be in a relaxed, uncompressed state that biases trigger <NUM> to the configuration of <FIG>. Opening <NUM> of slider <NUM> may be offset from agent inlet <NUM>, such that agent <NUM> may not pass through opening <NUM> and agent inlet <NUM>.

In use, an operator may depress trigger <NUM>, which may be an example of actuation mechanism <NUM>. A greater force may be required to compress spring <NUM> than to open button valve <NUM> to allow force of fluid from source <NUM> through fluid inlet <NUM>. For example, a compression of trigger <NUM> required to depress a button <NUM> of button valve <NUM> and open button valve <NUM> may be approximately <NUM> (<NUM> inches). Additionally or alternatively, spring <NUM> may partially compress to open button valve <NUM>, and further compression of spring <NUM> may be required in order to translate opening <NUM> sufficiently that it is in communication with agent inlet <NUM>. A further compression of trigger <NUM> required to compress spring <NUM> may be approximately <NUM> (<NUM> inches). Thus, a total throw of trigger <NUM> may be approximately <NUM> (<NUM> inches). A force depressing trigger <NUM> may initially translate spring <NUM> to open button valve <NUM> and to activate flow of fluid from source <NUM> through fluid inlet <NUM>. Fluid may flow into fluid inlet <NUM>, into a fluid nozzle chamber <NUM>. Fluid may pass through an opening <NUM> of fluid nozzle chamber <NUM>, into mixing chamber <NUM>. Fluid may then exit via outlet <NUM>. In the first configuration, agent <NUM> may not be delivered via outlet <NUM>, since opening <NUM> is not aligned with agent inlet <NUM>.

Thereafter, as force on trigger <NUM> is increased, spring <NUM> may be compressed (or may be further compressed). Compression of spring <NUM> will enable arm <NUM> to rotate about axis C (or further about axis C). Rotation of arm <NUM> may, in turn, cause slider <NUM> to translate in the first direction (to the left in the Figures), aligning opening <NUM> with agent inlet <NUM>, transitioning metering mechanism <NUM> to the second configuration of <FIG>. In the second configuration, fluid from source <NUM> may continue to flow as described above, with respect to the first configuration (<FIG>). Because opening <NUM> is aligned with agent inlet <NUM> and in fluid communication with agent inlet <NUM>, agent <NUM> may also pass through opening <NUM> and agent inlet <NUM>. Agent <NUM> may then enter mixing chamber <NUM>, where it may mix with fluid from source <NUM>. The combined agent <NUM> and fluid may then be delivered via outlet <NUM>.

Trigger <NUM> may include an opening <NUM>, which may be, for example, an elliptical shape. Opening <NUM> may receive components (not shown) that couple trigger <NUM> to spring <NUM>, while allowing for necessary movement of trigger <NUM> relative to stationary spring <NUM> and button valve <NUM>.

When a user releases trigger <NUM>, spring <NUM> may first decompress, causing slider <NUM> to return to a configuration that misaligns opening <NUM> and agent inlet <NUM>. Because opening <NUM> may be offset from agent inlet <NUM>, agent <NUM> may not pass through agent inlet <NUM>. However, because button valve <NUM> may remain open, fluid may continue to flow from source <NUM> through fluid inlet <NUM> for a time, until button valve <NUM> then closes.

<FIG> show another example body <NUM>, which may be a component of system <NUM>. Body <NUM> may have any of the features of body <NUM> of <FIG>. The discussion of <FIG>, herein, highlights differences between body <NUM> and body <NUM>. A fluid inlet <NUM> of body <NUM> may be in direct fluid communication with a fluid nozzle chamber <NUM>, without requiring fluid to first pass through a cavity <NUM>. A valve <NUM> may include only one stem portion <NUM>, which may have any of the properties of second portion <NUM>. Stem portion <NUM> may include an opening <NUM> (like opening <NUM>) and may be sealingly slidable within cavity <NUM>.

Flow to fluid inlet <NUM> may be controlled via a valve <NUM>, which may be, for example, a button valve. Valve <NUM> may actuate independently of valve <NUM>. Thus, valve <NUM> may be opened, allowing a flow of fluid to enter fluid inlet <NUM> and exit outlet <NUM>. Meanwhile, valve <NUM> may separately be actuated to permit flow of agent <NUM> through agent inlet <NUM>.

<FIG> shows a first configuration, in which valve <NUM> is closed and valve <NUM> is in a first configuration, in which opening <NUM> is not aligned (not in fluid communication) with an agent inlet <NUM>. In the first configuration, fluid may not pass through fluid inlet <NUM>, and agent may not pass through agent inlet <NUM>, so that neither fluid nor agent is delivered via outlet <NUM>.

<FIG> shows a second configuration, in which valve <NUM> is open and valve <NUM> is in a second configuration, in which opening <NUM> is aligned with agent inlet <NUM> so as to be in fluid communication with agent inlet <NUM>. In the second configuration, fluid may pass through fluid inlet <NUM>, and agent <NUM> may pass through agent inlet <NUM>, so that fluid and agent <NUM> may combine in mixing chamber <NUM> and be delivered from outlet <NUM>.

Body <NUM> may be configured so that valve <NUM> may be actuated to the second configuration only when valve <NUM> is open. Thus, agent <NUM> may not enter mixing chamber <NUM> if fluid from source <NUM> is not also delivered to mixing chamber <NUM>. In operation, a user may actuate a first actuation mechanism <NUM> (which may be, for example, a button of valve <NUM>). Fluid may flow through body <NUM> and out of outlet <NUM>. A user may then actuate a second actuation mechanism (not shown) to transition valve <NUM> to the second configuration to deliver a combination of agent <NUM> and fluid. A user may not be able to release first actuation mechanism <NUM> without first releasing the second actuation mechanism. After the second actuation mechanism is released, valve <NUM> may transition back to the first configuration of valve <NUM> due to a restorative force of a spring <NUM>, which may have any of the properties of second spring <NUM>. A user may then release first actuation mechanism <NUM> to close valve <NUM> and stop flow of fluid through fluid inlet <NUM>.

<FIG> show aspects of a body <NUM> that may form a part of delivery system <NUM>. <FIG> show cross-sectional views of body <NUM> in first and second configurations, respectively, and <FIG> show aspects of a turbine <NUM> that may be a component of body <NUM>.

As shown in <FIG>, a body <NUM> may have an agent inlet <NUM>, a fluid inlet <NUM>, and an outlet <NUM>, in fluid connection with one another via a chamber <NUM>.

Turbine <NUM> may be disposed in chamber <NUM>. Turbine <NUM> may include a plurality of blades <NUM> extending radially outward from a central body <NUM> (see <FIG>). Although three blades <NUM> are shown, it will be appreciated that other numbers of blades <NUM> may be utilized. Blades <NUM> may have any suitable shape, including the shape shown. Blades <NUM> may be formed from any suitable material, including rigid or flexible material, such as metals or plastics. Turbine <NUM> may also have a stop mechanism <NUM>, which may extend radially outward from central body <NUM>. Stop mechanism <NUM> may have any suitable shape, including a wedge shape, which may be a curved wedge shape. Stop mechanism <NUM> may be made from any suitable material, including rigid materials.

Turbine <NUM> may be fixedly connected to an axle <NUM> and may be rotatable about axle <NUM>. Axle <NUM> may extend from central body <NUM> and may also be fixedly connected to a round gear <NUM>, which may include teeth. Via axle <NUM>, turbine <NUM> and gear <NUM> may rotate together, in unison. Gear <NUM> may be formed of any suitable material and may include any suitable number of teeth. Turbine <NUM> and gear <NUM> may have any suitable size.

Gear <NUM> may interact with a linear rack <NUM>. Linear rack <NUM> may be movable relative to gear <NUM>, along a direction transverse to a longitudinal axis of agent inlet <NUM> (e.g., perpendicular to agent inlet <NUM>, left/right in the Figures). Rack <NUM> may include an opening 764a formed therein. A spring <NUM> may extend from an end of rack <NUM> furthest from gear <NUM>, and a first end of spring <NUM> may be fixed relative to rack <NUM>. A second end of spring <NUM> may be fixed relative to a surface <NUM> defining chamber <NUM>.

In a first configuration, shown in <FIG>, actuation mechanism <NUM> (<FIG>) may not be activated, and fluid may not flow from source <NUM> to fluid inlet <NUM>. Turbine <NUM>, gear <NUM>, and rack <NUM> may each be stationary. Spring <NUM> may be in a relaxed state. Rack <NUM> may be positioned so that opening 764a is not aligned with (not in fluid communication with) agent inlet <NUM>. Rack <NUM> may include seals <NUM> to prevent agent from moving between an outer surface of rack <NUM> and a surface of chamber <NUM>. In the first configuration, agent <NUM> may not enter chamber <NUM> because opening 764a is not aligned with (not in fluid communication with) agent inlet <NUM>.

When an actuation mechanism (<FIG>) is activated, flow from source <NUM> to fluid inlet <NUM> may be permitted. Fluid from fluid inlet <NUM> may interact with blades <NUM> to cause turbine <NUM> to rotate. Rotation of turbine <NUM> may cause corresponding rotation of gear <NUM>. Rotation of gear <NUM> may cause rack <NUM> to translate in a first direction (to the left in the Figures), such that opening 764a moves closer to agent inlet <NUM>. Spring <NUM> may be compressed as rack <NUM> translates, because a force from fluid on turbine <NUM> may overcome a restorative force of spring <NUM>. As shown in <FIG>, in a second configuration of body <NUM>, opening 764a may be aligned with (in fluid communication with) agent inlet <NUM>. Thus, agent <NUM> may be permitted to flow through opening 764a and into chamber <NUM>. In chamber <NUM>, agent <NUM> may mix with the fluid from source <NUM> and then exit through outlet <NUM>. However, before opening 764a is aligned with (in fluid communication with) agent inlet <NUM>, only fluid from source <NUM> may flow through chamber <NUM> and exit outlet <NUM>.

Activation of actuation mechanism <NUM> may cause, either immediately or following a delay, a tab <NUM> to extend from a surface <NUM> of body <NUM>. Tab <NUM> may extend in a direction perpendicular to axle <NUM>. <FIG> shows turbine <NUM> and tab <NUM> prior to extension of tab <NUM> (e.g., prior to activation of actuation mechanism <NUM>). <FIG> shows turbine <NUM> and tab <NUM> after tab <NUM> has been extended from surface <NUM>. Tab <NUM> may interact with stop mechanism <NUM> to prevent further rotation of turbine <NUM> after stop mechanism <NUM> contacts tab <NUM>. Tab <NUM> and stop mechanism <NUM> may stop gear <NUM> from continuing to rotate and thereby stop rack <NUM> from translating past a desired position, where opening 764a aligns with agent inlet <NUM>.

When actuation mechanism <NUM> is released, a flow of fluid through fluid inlet <NUM> may be eliminated or reduced, thereby eliminating or reducing a force on blades <NUM>. A restorative force of spring <NUM> may overcome a force of fluid (if any) on turbine <NUM>, causing rack <NUM> to translate in a second direction, opposite the first direction. Rack <NUM> may, in turn, cause rotation of gear <NUM>, which may cause rotation of turbine <NUM>, in a direction opposite to a direction of rotation while translating from the first configuration to the second configuration. Tab <NUM> may also retract. Opening 764a may no longer be aligned with (in fluid communication with) agent inlet <NUM>, so agent <NUM> may no longer flow through agent inlet <NUM>. Where some flow of fluid through fluid inlet <NUM> continues, fluid may continue to exit outlet <NUM>, after a flow of agent <NUM> has ceased. Alternatively, body <NUM> may include a purge line, which requires actuation by another mechanism (e.g., a button). Alternatively, actuation mechanism <NUM> may have three positions. In a first position of actuation mechanism <NUM>, no flow of fluid through fluid inlet <NUM> may occur. In a second position, fluid may be permitted to flow, but tab <NUM> or another component may interact with rack <NUM> to stop movement of rack <NUM> before opening 764a aligns with agent inlet <NUM>, thereby preventing flow of agent <NUM>. In a second position, tab <NUM> or another component may be retracted/deactivated to permit rotation of turbine <NUM> and permit flow of agent <NUM> while fluid flows through fluid inlet <NUM>. Alternatively, gear ratios between gear <NUM> and linear rack <NUM>, a length of rack <NUM>, and a strength of spring <NUM> may be chosen such that, when actuation mechanism <NUM> is activated, a known duration and/or amount of fluid from fluid inlet <NUM> may flow prior to alignment of opening 764a and agent inlet <NUM>, providing a flow of fluid without agent <NUM>. Following alignment of opening 764a and agent inlet <NUM>, agent <NUM> may flow via agent inlet <NUM>. If a user desires flow of fluid following a delivery of agent <NUM>, the user may release actuation mechanism <NUM> and reactivate actuation mechanism <NUM>. The user may only activate actuation mechanism for an amount of time such that fluid flows but agent does not flow (because opening 764a and agent inlet <NUM> do not align).

Claim 1:
A device for delivering an agent, comprising:
a source (<NUM>) of agent (<NUM>);
a body (<NUM>, <NUM>) having an agent inlet (<NUM>, <NUM>) for receiving agent from the source of agent and a fluid inlet (<NUM>, <NUM>) for receiving fluid from a source (<NUM>) of fluid;
a mixing chamber (<NUM>, <NUM>) for receiving the fluid and the agent;
an outlet (<NUM>) in fluid communication with the mixing chamber to deliver the fluid and the agent;
a valve (<NUM>) positioned between the outlet and the source of agent and between the outlet and the fluid inlet, the valve configured for controlling a flow of the fluid through the fluid inlet and a flow of the agent through the agent inlet; and
an actuator (<NUM>) operatively connected to the valve and configured to:
<NUM>.) move the valve to a first configuration to deliver a first flow of the fluid substantially free from the agent through the outlet;
<NUM>.) after delivering the first flow, move the valve to a second configuration to deliver a second flow of the fluid and the agent through the outlet; and
<NUM>.) after delivering the second flow, move the valve to a third configuration to deliver a third flow of the fluid substantially free from the agent through the outlet.