Patent Description:
Various aspects of the present disclosure relate generally to devices and methods for delivering agents. More specifically, in embodiments, the present disclosure relates to devices for delivery of powdered agents, such as hemostatic agents.

In certain medical procedures, it may be necessary to minimize or stop 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 a device for the expression of a hemostatic powder having an elongated reservoir with a manual air pump, such as a bellows, at a proximal end and an expression port at a distal end. A porous filter is slidably disposed within the reservoir between the bellows and plunger and the expression port, and a spring is disposed within the reservoir between the air pump and the plunger. The powder is disposed within the reservoir between the porous filter and the expression port, and the pump is in a fluid communication with the expression port through the porous filter and through the powder. <CIT> discloses an applicator including: a first liquid flow path through which a first liquid containing fibrinogen passes; a second liquid flow path through which a second liquid containing thrombin passes; a confluence section in which the first liquid and the second liquid merge with each other to form a mixed liquid; and a gas flow path through which a gas for jetting the mixed liquid passes. At least part of a wall portion defining the confluence section is composed of a gas-permeable membrane that is impermeable to the mixed liquid and permeable to the gas. The length of the gas-permeable membrane in a direction in which the mixed liquid flows through the confluence section is <NUM> to <NUM>. The flow rate of the gas permeating through the gas-permeable membrane is <NUM> to <NUM>/minute. 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>. Further embodiments of the claimed invention are described in the dependent 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 "diameter" may refer to a width where an element is not circular. The term "distal" refers to a direction away from an operator, and the term "proximal" refers to a direction toward an operator. The term "exemplary" is used in the sense of "example," rather than "ideal. " 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 present disclosure and together with the description, serve to explain the principles of the disclosure.

Embodiments of this disclosure relate to enclosures for storing an agent (e.g., a powdered agent) and metering/actuation mechanisms to deliver the agent to a site of a medical procedure. The enclosure may include a sintered filter through which a pressurized fluid may pass. The agent may be received within a channel of the sintered filter. When the pressurized fluid passes through the sintered filter, it may enter the chamber having the agent at a variety of different vectors at the same time and may fluidize the agent. Aspects of the sintered filter and/or the metering/actuation mechanisms may facilitate flow of the pressurized fluid, even when the agent is not being delivered, which may assist in preventing or minimizing clogging during depressurization of the device.

1A shows a delivery system <NUM>, which may be a powder delivery system. Delivery system <NUM> may include a body <NUM>. Body <NUM> may include or may be configured to receive an enclosure <NUM> (or other source) storing an agent. Enclosure <NUM> may be coupled to body <NUM> for providing agent to body <NUM>, or a lid/enclosure of the agent may be screwed onto, or otherwise coupled to, enclosure <NUM> for supplying the agent to enclosure <NUM>. The agent may be, for example, a powdered agent, such as a hemostatic agent. The agent may alternatively be another type of agent or material 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> may have a variety of features, to be discussed in further detail herein. <CIT>, discloses features of exemplary delivery devices and systems. The features of this disclosure may be combined with any of the features described in the above-referenced application. 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.

An actuation mechanism <NUM> may be used to activate flow of a pressurized fluid and/or agent. Fluid alone or a combination of agent and fluid may be delivered from outlet <NUM> of body <NUM>. As used herein, the terms "distal"/"first direction" may refer to a direction toward outlet <NUM> and away from enclosure <NUM>, and the terms "proximal"/"second direction" may refer to the opposite direction. Outlet <NUM> may be in fluid communication with a catheter <NUM> or other component for delivering the combination of agent and fluid to a desired location within a body lumen of a patient.

<FIG> show aspects of an example dispensing portion <NUM>. Dispensing portion <NUM> may be used in place of enclosure <NUM> of delivery device <NUM>. <FIG> show cross-sectional views, while <FIG> shows a perspective view. The views in <FIG> are rotated ninety degrees with respect to the views of <FIG> and <FIG>, respectively.

Dispensing portion <NUM> may include an enclosure <NUM> (which may have any of the properties of enclosure <NUM>) that stores an agent <NUM>. As shown in <FIG> and <FIG>, Enclosure <NUM> may be defined by inner surfaces of a housing <NUM> and a lid <NUM>. Housing <NUM> and/or lid <NUM> may include threads <NUM> enabling a distal end of lid <NUM> (a lower end, as shown in the Figures) to be screwed onto a proximal end of housing <NUM> (an upper end, as shown in the Figures). For example, an outer surface of housing <NUM> may include threads, and an inner surface of lid <NUM> may include threads.

Housing <NUM> may have a fluid inlet <NUM> (see <FIG>). A wall of housing <NUM> may form a protrusion <NUM>, which may define fluid inlet <NUM>. Protrusion <NUM> may include a lip or other structure, which may assist with mating with tubing or other structures used to deliver fluid. Although fluid inlet <NUM> is shown at a side portion of housing <NUM>, it will be appreciated that fluid inlet <NUM> may be in alternative locations. For example, fluid inlet <NUM> may be in a distal surface of housing <NUM> (the bottom of housing <NUM> in the Figures) or in lid <NUM>. Housing <NUM> may also have an outlet <NUM>. A catheter or other type of tubing <NUM> may define outlet <NUM>, as described in further detail below. Outlet <NUM> may be in fluid communication with outlet <NUM> of delivery system <NUM>.

A filter <NUM> may be disposed within a proximal portion of enclosure <NUM>. Filter <NUM> may have a wall <NUM>. In cross-sections of filter <NUM> along a longitudinal axis of filter <NUM>, wall <NUM> may have a generally annular shape. An inner surface of wall <NUM> may define a channel <NUM>. Agent <NUM> may be at least partially received within channel <NUM>. Surfaces of wall <NUM> and surfaces of housing <NUM> may serve to form boundaries for agent <NUM>.

Filter <NUM> and channel <NUM> may be substantially conical or funnel-shaped. At a proximal end of filter <NUM> (the top of filter <NUM> in the Figures), channel <NUM> may have its greatest diameter (perpendicular to a longitudinal axis of channel <NUM>). Wall <NUM> may be angled such that, moving distally (toward the bottom of the Figures), channel <NUM> tapers to a smaller diameter. Further details regarding a shape of channel <NUM> are described below.

The proximal end of filter <NUM> may be sealed with respect to housing <NUM>. For example, an outer surface of wall <NUM> may be sealed with respect to an inner surface of housing <NUM>. Sealing may occur via, e.g., structures that are integrally formed with a remainder of filter <NUM>, seals fitted on a remainder of filter <NUM> (e.g., O-ring seal(s)), and/or substances such as adhesives that secure filter <NUM> to housing <NUM>. Because filter <NUM> is sealed with respect to housing <NUM>, agent and/or fluid may not pass between an outer surface of wall <NUM> and an inner surface of housing <NUM> at a proximal end of filter <NUM>. A distal end of filter <NUM> may also be sealed with respect to housing <NUM>. For example, a distal end of filter <NUM> may be sealed with respect to an inner surface of a distal wall of housing <NUM> (the bottom wall in the Figures).

Wall <NUM> may have a constant thickness or a varying thickness. Wall <NUM> may be sintered, such that tortuous passages are formed between an outer surface of wall <NUM> and an inner surface of wall <NUM>. The tortuous passages may be sized such that agent <NUM> does not pass through the passages between the inner surface and outer surface of wall <NUM>. Fluid from fluid inlet <NUM> may be permitted to flow through the openings in wall <NUM>, as described in further detail below. Openings may have sizes between approximately <NUM> microns (i.e., µm) and <NUM> microns (e.g., <NUM> microns). Particle sizes of agent <NUM> may range from approximately <NUM> microns to <NUM> microns (e.g., <NUM> microns to <NUM> microns). Filter <NUM> may be formed via, for example, additive manufacturing techniques (e.g., three-dimensional printing). For example, a pattern or model created to form filter <NUM> may incorporate sintered openings. Such openings may be formed by an algorithm that divides a model filter <NUM> into triangles or other shapes. <FIG> and <FIG> show portions of a filter <NUM>' made according to such an algorithm. <FIG> shows a zoomed-in portion of such a filter <NUM>', while <FIG> shows a wider view of such a filter <NUM>'. Other methods, such as triply periodic minimal surface ("TPMS") may alternatively be used to form gyroids, diamonds, or other shapes. The part may be printed using, for example, powder bed fusion methods (e.g., via electron beam or laser beam. Alternatively, a solid model of filter <NUM> may be created, and energy may be applied to form pores (passages) in wall <NUM>. For example, a laser may be applied to a combination of metal powder and a foaming agent, which results in the development of pores/passages. Alternatively, a laser may be applied with energy calibrated so as to form pores as a metal powder is fused. <FIG> show examples of such a filter <NUM>" made according to such laser-based methods. <FIG> shows a magnified version of <FIG> to show details of pores of filter <NUM>". <FIG> shows a cross-sectional view of filter <NUM>".

The tortuous passages of wall <NUM> may cause fluid flowing through filter <NUM> to enter channel <NUM> at a wide variety of vectors, including angles, velocities, and/or pressures at the same time. The fluid exiting wall <NUM> may have a turbulent flow pattern (e.g., a radial pattern). As also described below, the varying vectors with which fluid enters channel <NUM> may cause agent <NUM> within channel <NUM> to become fluidized. The turbulent flow of fluid (which may result in fluidization, such as a liquid sand effect, of agent <NUM>) may aid in a flow of agent <NUM> through outlet <NUM> and may prevent or minimize clogging of agent <NUM>. Fluidization may break up agglomerates of agent <NUM>. Agent <NUM> may include, for example, semi-cohesive materials, such as chitosan acetate.

Catheter <NUM> or another component (e.g., tubing) may be received within a distal end of channel <NUM>. For example, outer surfaces of catheter <NUM> may fit against the inner surface of wall <NUM>. Catheter <NUM> may be fixed to filter <NUM> via adhesive, friction fit, ridges/grooves, or other suitable means. Catheter <NUM> may define outlet <NUM>, which may be in fluid communication with outlet <NUM>.

A rotatable shaft <NUM> may extend through enclosure <NUM> such that a longitudinal axis of shaft <NUM> is transverse to (e.g., substantially perpendicular to) a longitudinal axis of enclosure <NUM> and/or a proximal portion of catheter <NUM>. In <FIG>, shaft <NUM> is shown extending longitudinally into and out of the page.

An opening <NUM> may be formed in shaft <NUM>. Opening <NUM> may extend through an entirety of shaft <NUM>, substantially perpendicularly (or at least offset) to the longitudinal axis of shaft <NUM>. Opening <NUM> may be substantially parallel to a longitudinal axis of enclosure <NUM> in some configurations (such as the configuration shown in <FIG>). As described in further detail below, in a first configuration of shaft <NUM> (<FIG>, <FIG>), longitudinal axes of opening <NUM> and channel <NUM> may be aligned, such that fluid and/or agent <NUM> may pass from a portion of channel <NUM> that is proximal of shaft <NUM>, through opening <NUM>, and into a portion of channel <NUM> that is distal to shaft <NUM>. In a second configuration of shaft <NUM>, in which shaft <NUM> is rotated relative to the first configuration (<FIG>, <FIG>), the longitudinal axis of opening <NUM> may be misaligned with respect to the longitudinal axis of channel <NUM>, such that fluid and/or agent <NUM> does not pass between the portion of channel <NUM> that is proximal of shaft <NUM> into the portion of channel <NUM> that is distal to shaft <NUM>, via opening <NUM>. As shaft <NUM> is rotated, the longitudinal axes of channel <NUM> and opening <NUM> may align and misalign. For example, the longitudinal axes of channel <NUM> and opening <NUM> may be aligned with each <NUM> degree rotation of shaft <NUM>.

Filter <NUM> may be configured so as to accommodate shaft <NUM>. For example, cylindrical conduits <NUM>, <NUM> of filter <NUM> may extend radially outward from a longitudinal axis of channel <NUM>. Cylindrical conduits <NUM>, <NUM> may have longitudinal axes that are parallel with the longitudinal axis of shaft <NUM>. Shaft <NUM> may be received within cylindrical conduits <NUM>, <NUM>. In some examples, cylindrical conduits <NUM>, <NUM> may together form a cylindrical conduit that has an opening forming channel <NUM> extending through the cylindrical conduit, transversely to a longitudinal axis of the cylindrical conduit. Cylindrical conduits <NUM>, <NUM> and other surfaces of filter <NUM> may be configured so as to form a sleeve about shaft <NUM>. Surfaces of shaft <NUM> may form a seal with inner surfaces of wall <NUM> such that agent <NUM> may not move distally past shaft <NUM> when shaft <NUM> is in the second configuration, and opening <NUM> is not in fluid communication with channel <NUM>. The seal may be formed due to, for example, a material forming filter <NUM> and/or shaft <NUM>. Shaft <NUM> may have the effect of dividing channel <NUM> into a proximal portion <NUM>, proximal of shaft <NUM>, and a distal portion <NUM>, distal to shaft <NUM>.

Shaft <NUM> may extend through openings <NUM> in sides of housing <NUM>. Longitudinal axes of openings <NUM> may be substantially parallel to the longitudinal axis of shaft <NUM> and the longitudinal axes of openings <NUM> may be collinear with one another and/or with shaft <NUM>. Protrusions <NUM> may extend around and define openings <NUM>. A shape of protrusions <NUM> may be complementary to a shape of shaft <NUM>. For example, protrusions <NUM> may have an annular or cylindrical shape. Seals <NUM> (e.g., O-ring seals) may be disposed about shaft <NUM> to create a seal between shaft <NUM> and inner surfaces of protrusion <NUM>. Seals <NUM> may be disposed within circumferential grooves of shaft <NUM>, as shown in the Figures, or may alternatively be disposed around a flush surface of shaft <NUM>. Alternatively, seals <NUM> may be integrally formed with shaft <NUM>. Seals <NUM> may prevent a flow of fluid and/or agent between shaft <NUM> and inner surfaces of protrusion <NUM>.

Shaft <NUM> may have a first configuration, shown in <FIG> and <FIG>, and a second configuration, shown in <FIG> and <FIG>. In the first configuration (<FIG> and <FIG>), agent <NUM> may flow through outlet <NUM>. In the second configuration (<FIG> and <FIG>), agent <NUM> does not flow through outlet <NUM> (i.e., agent <NUM> is prevented and/or blocked from flowing through outlet <NUM>).

Prior to use of delivery system <NUM>, shaft <NUM> may be in the second configuration of <FIG> and <FIG>. In the second configuration, a longitudinal axis of opening <NUM> may be misaligned with or offset from channel <NUM> such that opening <NUM> is not in fluid communication with channel <NUM>. Agent <NUM> cannot flow distally past shaft <NUM> and through outlet <NUM> because opening <NUM> is not in fluid communication with channel <NUM>. Agent <NUM> may be retained within proximal portion <NUM> of channel <NUM> and other portions of enclosure <NUM>.

Upon activation of actuation mechanism <NUM> or another actuation mechanism (transforming shaft <NUM> to the first configuration), fluid may be permitted to flow through fluid inlet <NUM> (see <FIG>). The fluid from fluid inlet <NUM> may pass through sintered portions of wall <NUM> of distal portion <NUM> of filter <NUM>. The fluid may flow into channel <NUM>, into catheter <NUM>, and out of outlet <NUM>. The fluid from inlet <NUM> may also pass through sintered portions of wall <NUM> into proximal portion <NUM> of channel <NUM>. However, while shaft <NUM> remains in the second configuration, agent <NUM> may not flow into opening <NUM> to the portion of channel <NUM> in distal portion <NUM> of filter <NUM>. The arrows in <FIG> and <FIG> show the flow of fluid in the first configuration, while fluid flows through fluid inlet <NUM>.

When shaft <NUM> is rotated to the first configuration (<FIG> and <FIG>), via actuation mechanism <NUM> or via a separate actuator, agent <NUM> may be permitted to flow through channel <NUM>, to distal portion <NUM>. Fluid may continue to flow through wall <NUM> of filter <NUM>, as described above, into proximal portion <NUM> and distal portion <NUM>. The fluid flowing into channel <NUM> (e.g., into proximal portion <NUM>) may fluidize agent <NUM>.

An inner surface of wall <NUM> and a surface defining opening <NUM> may be shaped such that channel <NUM> and opening <NUM> have a varying diameter between a proximal end of channel <NUM> and a distal end of channel <NUM>. As agent <NUM> moves distally, it encounters portions of channel <NUM> that vary in diameter, which reduces clogging of agent <NUM> within channel <NUM>. Agent <NUM> may be prone to bridging, which may result in clogging absent the variations in diameter of channel <NUM>.

As described above, at a first, proximal portion <NUM> of channel <NUM>, an inner surface of wall <NUM> may taper inward, moving in a distal direction. An angle of first portion <NUM> may be greater than (i.e., steeper than) an angle of repose of agent <NUM>. An angle of repose of agent <NUM> may be an angle formed by a cone-like pile of agent <NUM> as agent <NUM> flows through an orifice and collects on a surface in the cone-like pile. The angle of repose may be the angle between the surface onto which the agent <NUM> flows and a surface of the cone-like pile. The angle of repose may be related to friction or resistance to movements between particles of agent <NUM>. Because wall <NUM> may have an angle greater than the angle of repose of agent <NUM>, agent <NUM> may flow freely through funnel channel <NUM>, due to a force of gravity.

Just proximally of shaft <NUM>, at a second portion <NUM> of channel <NUM>, the inner surface of wall <NUM> may have a constant diameter. A proximal end of opening <NUM> may be narrower (e.g., slightly narrower) than the portion of channel adjacent to the proximal end of opening <NUM>. Alternatively, a proximal end of opening <NUM> may have substantially the same width as or a greater width than the portion of channel <NUM> that is adjacent and proximate to opening <NUM>.

Opening <NUM> may have first portion <NUM>, second portion <NUM>, and third portion <NUM>. In first portion <NUM>, the inner surface of shaft <NUM> may taper radially inward moving in a distal direction such that a size of opening <NUM> decreases. In second portion <NUM>, opening <NUM> may have a constant or substantially constant diameter. In third portion <NUM>, the inner surface of shaft <NUM> may taper radially outward moving in the distal direction, such that the size of opening <NUM> increases. A distal end of opening <NUM> may have a size that is the same as or substantially the same as the size of channel <NUM> adjacent to the distal end of opening <NUM>.

Distally of the distal end of opening <NUM>, a third portion <NUM> of channel <NUM> may be defined by inner surfaces of wall <NUM> that taper inward moving distally to a fourth portion <NUM> of channel <NUM>, which may have a constant diameter. The diameter of fourth portion <NUM> may be substantially the same as an inner diameter of catheter <NUM>.

In passing through channel <NUM>, agent <NUM> first travels through a narrowing portion (first portion <NUM>), through a constant diameter portion (second portion <NUM>), through a wider portion (a proximal end of opening <NUM>), into a narrowing portion (first portion <NUM>), through a constant diameter portion (second portion <NUM>), through a widening portion (third portion <NUM>), through a narrowing portion (third portion <NUM>), and then through a constant diameter portion <NUM>, into catheter <NUM>. These alternating widening and narrowing segments of passage <NUM> and opening <NUM> may result in decreased clogging of agent <NUM> in some embodiments due to, for example, a reduction in bridging of agent <NUM>. Portions of channel <NUM> that are tapering and/or angled may have an angle of approximately <NUM> degrees.

Following a desired flow of agent <NUM>, shaft <NUM> may be transitioned from the first configuration to the second configuration, so that agent <NUM> is no longer capable of flowing through outlet <NUM>. Fluid may continue to flow from inlet <NUM> through outlet <NUM>, as described above. Such continued fluid flow may help purge agent delivery device <NUM>.

During flow of fluid, enclosure <NUM> may become pressurized. Aspects of dispensing portion <NUM> may facilitate depressurization of enclosure <NUM>, in particular, while shaft <NUM> is in the second configuration. Were agent <NUM> permitted to flow out of outlet <NUM> during depressurization, agent <NUM> may exit outlet <NUM>, which may lead to clogging of agent delivery device <NUM>. Filter <NUM> and shaft <NUM> allow enclosure <NUM> to depressurize without a risk of agent <NUM> being drawn out of exit <NUM> when shaft <NUM> is in the second configuration. Fluid may flow out of outlet <NUM> without a flow of agent <NUM>, because shaft <NUM> does not permit passage of agent <NUM> through outlet <NUM>.

Dispensing portion <NUM> may also include a release valve <NUM> (<FIG>). Release valve <NUM> may provide a mechanism for depressurizing chamber <NUM>. For example, release valve <NUM> may be particularly helpful in circumstances in which pressure requires emergency release (e.g., during a procedure). Release valve <NUM> may also provide a mechanism for depressurizing enclosure <NUM> during the ordinary course of a procedure. Release valve <NUM> may be used in addition to or in alternative to the depressurizing mechanics described above. A relief pressure may be approximately <NUM> bar above ambient pressure (<NUM> pounds per square inch gauge, PSIG).

Dispensing portion <NUM> may provide numerous benefits in certain embodiments. For example, filter <NUM> can provide for a turbulent flow of fluid as it combines with agent <NUM>. The turbulent flow of fluid may provide improvements to flow of agent <NUM> through outlet <NUM> as compared to devices without filter <NUM> and/or devices that do not allow for turbulent flow. Dispensing portion <NUM> also may allow depressurization of enclosure <NUM> without a flow of agent <NUM> into distal portions of delivery device <NUM>. The configuration of channel <NUM> and opening <NUM> may facilitate delivery of agent <NUM> without clogging (or without significant clogging) due to, for example, bridging of agent <NUM>.

<FIG> shows an alternative dispensing portion <NUM>. Dispensing portion <NUM> may have any of the properties of dispensing portion <NUM>, except where noted specifically herein. Like reference numbers are used where practical. Aspects of dispensing portion <NUM> may be combined with aspects of dispensing portion <NUM> and are not mutually exclusive.

Enclosure <NUM> may include a filter <NUM> disposed therein. Filter <NUM> may be manufactured according to the same techniques as filter <NUM> and may include the same type of material and the same type of tortuous passages. A shape of filter <NUM> may differ from a shape of filter <NUM>. A distal end of filter <NUM> (the top end in <FIG>) may extend further proximally in enclosure <NUM> as compared to filter <NUM>.

A rotatable shaft <NUM> may extend through enclosure <NUM> such that a longitudinal axis of shaft <NUM> is transverse to (e.g., substantially perpendicular to) a longitudinal axis of enclosure <NUM> and/or a proximal portion of catheter <NUM>. Rotatable shaft <NUM> may have any of the properties of rotatable shaft <NUM>. A shape of an opening <NUM> extending through shaft <NUM>, substantially perpendicularly to the longitudinal axis of shaft <NUM>, may differ from the shape of opening <NUM> of shaft <NUM>.

Inner surfaces of walls <NUM> of filter <NUM> may define a channel <NUM>. In a first, proximal portion <NUM> of channel <NUM>, an inner surface of wall <NUM> may taper inward toward a distal direction (the bottom of <FIG>). An angle between a surface defining first portion <NUM> may be greater than an angle of repose of agent <NUM> (e.g., the angle may be steeper than the angle of repose). Agent <NUM> may flow freely through portion <NUM> due to a force of gravity.

Proximally of shaft <NUM>, at a second portion <NUM> of channel <NUM>, the inner surface of wall <NUM> may extend in a direction that is substantially parallel to a longitudinal axis of channel <NUM>. Second portion <NUM> may have a tubular shape, with a substantially constant diameter.

Opening <NUM> may have a tubular shape, with a substantially constant diameter. Opening <NUM> may have substantially the same diameter as second portion <NUM>. Alternatively, a proximal end of opening <NUM> may have a greater or smaller width than second portion <NUM>. A distal end of opening <NUM> may have a size that is the smaller than the size of channel <NUM> adjacent to the distal end of opening <NUM>.

Distally of shaft <NUM>, channel <NUM> may have the same shape as channel <NUM>, described above. As noted above, the features of dispensing portions <NUM> and <NUM> are not mutually exclusive. For example, filter <NUM> may be utilized with shaft <NUM>, and filter <NUM> may be utilized with shaft <NUM>.

When shaft <NUM> is in a configuration allowing a flow of agent <NUM> through opening <NUM> (as shown in <FIG>), agent <NUM> may travel through a progressively smaller channel <NUM> as it travels distally within portion <NUM>, until it reaches portion <NUM>, in which a diameter of channel <NUM> is constant. Agent <NUM> may continue to pass through a region of constant diameter through opening <NUM>. Distal to opening <NUM>, agent <NUM> may encounter a larger diameter portion of passage <NUM> at a proximal end of portion <NUM>. A diameter of passage <NUM> may taper distally at portion <NUM>, until powder <NUM> encounters the constant diameter segment of passage <NUM> in portion <NUM>.

As with passage <NUM> and opening <NUM>, passage <NUM> and opening <NUM> may be configured to avoid clogging of agent <NUM> due to, for example, bridging of agent <NUM> across passage <NUM>/opening <NUM>. Aside from a shape of passage <NUM>, fluid and agent <NUM> may flow as described above with respect to <FIG>. The configuration of <FIG> may allow agent <NUM> to pass through a consistent diameter through second portion <NUM> and opening <NUM>. The sintered, neck-like structure of second portion <NUM> may assist with keeping agent <NUM> moving and fluidized through a narrowest section of the system.

<FIG> shows a portion of another dispensing portion <NUM>. Dispensing portion <NUM> may have any of the properties of dispensing portions <NUM> or <NUM>, except where noted specifically herein. Like reference numbers are used where practical. Aspects of dispensing portions <NUM>, <NUM>, and/or <NUM> may be combined in various combinations and are not mutually exclusive.

Dispensing portion <NUM> may include a housing <NUM>, which may have any of the properties of housing <NUM>, except as specified herein. Housing <NUM> may define an enclosure <NUM>, which may have any of the properties of enclosure <NUM>.

Enclosure <NUM> may include a filter <NUM> disposed therein. Filter <NUM> may be manufactured according to the same techniques as filters <NUM>, <NUM> and may include the same type of material and the same type of tortuous passages. A shape of filter <NUM> may differ from a shape of filters <NUM>, <NUM>. Filter <NUM> may include a wall <NUM>. An inner surface of wall <NUM> may define a channel <NUM>, which may receive agent <NUM>. Filter <NUM> may be sealed relative to an inner surface of housing <NUM>, as described above with respect to filter <NUM> and housing <NUM>.

A rotatable shaft <NUM> may extend through enclosure <NUM> such that a longitudinal axis of shaft <NUM> is transverse to (e.g., substantially perpendicular to) a longitudinal axis of enclosure <NUM> and/or a proximal portion of catheter <NUM>. Rotatable shaft <NUM> may have any of the properties of rotatable shafts <NUM>, <NUM>. A shape of an opening <NUM> is shown as being the same as that of opening <NUM>. First portion <NUM> may have any of the properties of first portion <NUM>, second portion <NUM> may have any of the properties of second portion <NUM>, and third portion <NUM> may have any of the properties of third portion <NUM>. Alternatively, opening <NUM> may have a shape like that of opening <NUM> or may have an alternative shape. <FIG> shows rotatable shaft <NUM> in a configuration in which agent <NUM> is permitted to pass distally through opening <NUM> and outlet <NUM>.

Shaft <NUM> may extend through collinear openings <NUM> in housing <NUM>. Housing <NUM> may not include structures corresponding to protrusions <NUM> but instead may include openings disposed through and flush with a surface of housing <NUM>. Shaft <NUM> may not include structures corresponding to seals <NUM>. Alternatively, housing <NUM> may be configured like housing <NUM> and may include protrusions <NUM> and/or shaft <NUM> may include seals <NUM>. Alternatively, other structures may be used in any of dispensing portions <NUM>, <NUM>, and/or <NUM> to seal shaft <NUM>, <NUM>, and/or <NUM> relative to enclosure <NUM> and/or <NUM>.

Channel <NUM> may include a tapered portion <NUM> (proximally and distally of shaft <NUM>) and a straight portion <NUM> (distally of shaft <NUM>). An angle of a surface defining first portion <NUM> may be greater than (i.e., steeper than) an angle of repose of agent <NUM>. Agent <NUM> may flow freely through portion <NUM> due to a force of gravity. Straight portion <NUM> may be, for example, tubular. Shaft <NUM> may extend through tapered portion <NUM>. Filter <NUM> is shown as lacking structures corresponding to cylindrical conduits <NUM>, <NUM>. Alternatively, filter <NUM> may include structures similar to protrusions <NUM>.

As agent <NUM> moves distally through channel <NUM>, agent <NUM> may first pass through tapered portion <NUM> until it reaches opening <NUM>. A proximal end of opening <NUM> may be narrower than a portion of channel <NUM> adjacent to the proximal end of opening <NUM>. Within opening <NUM>, agent <NUM> may pass through first portion <NUM>, which tapers inward distally, until it reaches second portion <NUM>, which may have a constant diameter. Agent <NUM> may then pass through third portion <NUM>, which may have a width that tapers outward in the distal direction.

A portion of channel <NUM> adjacent to a distal end of opening <NUM> may have substantially the same width as the distal end of opening <NUM>. The agent <NUM> may continue to pass through tapered portion <NUM>, until it reaches straight portion <NUM>. A width of straight portion <NUM> may be the same as an internal diameter of catheter <NUM>. Agent <NUM> may pass from straight portion <NUM> into catheter <NUM> and through outlet <NUM>.

As with passages <NUM>, <NUM> and openings <NUM>, <NUM>, passage <NUM> and opening <NUM> may be configured to avoid clogging of agent <NUM> due to, for example, bridging of agent <NUM> across passage <NUM>/opening <NUM>. Aside from a shape of passage <NUM>, fluid and powder <NUM> may flow as described above with respect to <FIG>.

<FIG> and <FIG> show an alternative dispensing portion <NUM>. Dispensing portion <NUM> may have properties of dispensing portions <NUM>, <NUM>, <NUM>, described above, except where as specified below. Aspects of dispensing portion <NUM> may be combined with aspects of dispensing portions <NUM>, <NUM>, <NUM>, described above.

Dispensing portion <NUM> may include a first housing <NUM>, which may have any of the properties of housings <NUM>, <NUM>, except as specified herein. A lid <NUM>, which may have any of the properties of lid <NUM>, may be retained on first housing <NUM> via threads <NUM>.

Housing <NUM> may define a first enclosure <NUM>, which may have any of the properties of enclosures <NUM>, <NUM>. Agent <NUM> may be stored within first enclosure <NUM>. Inner surfaces of walls of housing <NUM> may define a funnel <NUM>. An angle of funnel <NUM> may be greater (i.e., steeper than) than an angle of repose of agent <NUM>. Agent <NUM> may flow freely through funnel <NUM> due to a force of gravity.

Housing <NUM> may be disposed proximally of a second housing <NUM>. Second housing <NUM> may include walls <NUM>. Walls <NUM> may be partially received within a rim <NUM> of first housing <NUM>. An inner surface of rim <NUM> and an outer surface of walls <NUM> may each include threads, which may be used to mate rim <NUM> with walls <NUM>. Second housing <NUM> may define a second enclosure <NUM>. Second housing <NUM> may have fluid inlet <NUM>.

A filter <NUM> may be received within a distal portion of enclosure <NUM>. Filter <NUM> may have the properties of any of filters <NUM>, <NUM>, <NUM>. A proximal end and a distal end of filter <NUM> may be sealed with respect to inner surfaces of second housing <NUM> defining enclosure <NUM>, using any of the mechanisms described above with respect to filter <NUM>. Filter <NUM> may have a substantially funnel shape, defining a channel <NUM>. Catheter <NUM> may be received within channel <NUM> and may define outlet <NUM>.

First housing <NUM> may define an opening <NUM> near a distal end of housing <NUM>. Opening <NUM> may extend in a plane substantially perpendicular to a longitudinal axis of enclosures <NUM>, <NUM>. A slider <NUM> (e.g., a plate) may be received within opening <NUM> and may be movable in the plane of opening <NUM> (perpendicular to a longitudinal axis of enclosures <NUM>, <NUM>). Activation of actuation mechanism <NUM> or another actuation mechanism may cause slider <NUM> to transition between a first configuration (<FIG>) and a second configuration (<FIG>).

In the first configuration (<FIG>), slider <NUM> may intercept and/or cover a distal end of enclosure <NUM>, such that first enclosure <NUM> is not in fluid communication with enclosure <NUM>. Slider <NUM> and/or first enclosure <NUM> may include seals that prevent passage of agent <NUM> and/or fluid proximally or distally past slider <NUM> when slider <NUM> is in the first configuration. In the first configuration, when a flow of fluid is activated (e.g., via actuation mechanism <NUM>), fluid may pass through inlet <NUM>, through sintered portions of a wall of filter <NUM>, into channel <NUM>. Fluid may then pass into catheter <NUM> and through outlet <NUM>.

In the second configuration (<FIG>), slider <NUM> does not intercept or enclose (or at least partially does not intercept or enclose) the distal end of enclosure first <NUM>. Therefore, first enclosure <NUM> may be in fluid communication with second enclosure <NUM>, and agent <NUM> may flow from first enclosure <NUM> into second enclosure <NUM> in the second configuration. Agent <NUM> may enter channel <NUM>, where agent <NUM> may combine with fluid from inlet <NUM>. The fluid may fluidize agent <NUM>. Agent <NUM>, combined with the fluid, may pass through catheter <NUM> and through outlet <NUM>.

In operation, a user may activate actuation mechanism <NUM>, which may activate only a flow of fluid through inlet <NUM> or may activate a flow of fluid through inlet <NUM> and transition slider <NUM> from the first configuration to the second configuration. Alternatively, separate actuation mechanisms may be used to activate a flow of fluid through inlet <NUM> and to transition slider <NUM> from the first configuration to the second configuration. After slider <NUM> transitions to the second configuration, agent <NUM> may begin flowing through outlet <NUM>, as described above.

Following a delivery of a desired amount of agent <NUM>, slider <NUM> may be transitioned from the second configuration to the first configuration, stopping a flow of agent <NUM> through outlet <NUM>. A flow of fluid may or may not continue after slider <NUM> has been transitioned to the first configuration. As described above with respect to dispensing portion <NUM>, dispensing portion <NUM> may facilitate depressurization of chamber <NUM>. Because agent <NUM> is barred from entering chamber <NUM> in the second configuration of slider <NUM>, chamber <NUM> may be depressurized (pressurized fluid may exit outlet <NUM>) without agent <NUM> being drawn through outlet <NUM>. An ability to depressurize chamber <NUM> without drawing agent <NUM> through outlet <NUM> may prevent or minimize clogging of agent <NUM>.

<FIG> shows portions of an alternative dispensing portion <NUM>. Dispensing portion <NUM> may have features of dispensing portions <NUM>, <NUM>, <NUM>, <NUM>, described above. Dispensing portion <NUM> may include a housing <NUM>, which may have any of the features of housing <NUM>. Housing <NUM> may receive a lid (not shown), such as lid <NUM>. Housing <NUM> may define an enclosure <NUM>. A fluid inlet <NUM> and an outlet <NUM> may be in fluid communication with housing <NUM>.

A filter <NUM> may be received within a distal portion of housing <NUM>. Filter <NUM> may have properties of filter <NUM>, including the material properties of filter <NUM> and the tortuous passages formed therein. Proximal ends of filter <NUM> may be sealed relative to inner surfaces of <NUM>, by, for example, the mechanisms described above with respect to filter <NUM>. Filter <NUM> may be cylindrical and/or cup-shaped. Filter <NUM> may have a flat, distal wall <NUM> (a bottom surface, shown in <FIG>) and a cylindrical wall <NUM>. Filter <NUM> may define a channel <NUM>. Agent <NUM> may be received within channel <NUM> and other portions of enclosure <NUM>. An opening may be formed in distal wall <NUM>, which may be in fluid communication with outlet <NUM>. Although a structure corresponding to catheter <NUM> is not shown in <FIG>, it will be appreciated that a catheter such as catheter <NUM> may be received within outlet <NUM> and/or the opening in distal wall <NUM>.

In operation, a flow of fluid through inlet <NUM> may be activated. The fluid may pass through the walls of filter <NUM> (e.g., cylindrical wall <NUM>). Where, as discussed, above, inlet <NUM> is disposed on a distal surface of enclosure <NUM>, the fluid from inlet <NUM> may be piped through a cavity on the bottom of filter <NUM> (not shown). The fluid may have an exit filter <NUM> simultaneously along a variety of vectors, as described above (e.g., with respect to filter <NUM>). The fluid may combine with agent <NUM> and may fluidize agent <NUM>. The combined fluid and agent <NUM> may pass through outlet <NUM>.

As discussed above, filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may have sintered walls, with openings/pores formed therethrough. Alternatively, instead of a sintering process, the walls of the filters may be made porous through any other suitable process, including, for example, a three-dimensional (3D) printing process. The following description provides examples of pore sizes of filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and particle dimensions/sizes of agent <NUM>. Pores of filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may have sizes ranging from approximately <NUM> microns to approximately <NUM> microns (e.g., <NUM> microns or <NUM> microns). A size of the pores may be substantially uniform or may vary. As described above, the varying, simultaneous vectors of fluid passing through walls of filters <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may cause agent <NUM> to become fluidized (e.g., may have a liquid sand effect). Fluidization of agent <NUM> may have various advantages, including aerating agent <NUM>, reducing friction between particles of agent <NUM>, suspending particles of agent <NUM> in fluid (e.g., air or carbon dioxide) to propel them, faster delivery of particles of agent <NUM>, and/or delivery of agent <NUM> using less fluid. Fluidization may break up agglomerates of agent <NUM>. Agent <NUM> may include, for example, semi-cohesive materials, such as chitosan acetate.

In one embodiment, as seen in <FIG>, a filter <NUM> may include an intermediate wall <NUM> disposed between a proximal portion <NUM> and a distal portion <NUM> of filter <NUM>. A shape of filter <NUM> may be similar to the shape of filters <NUM>, <NUM>, <NUM>, <NUM> described above. Proximal portion <NUM> may have a greater cross-sectional dimension than distal portion <NUM>. Intermediate wall <NUM> may taper inwardly toward a distal direction relative to proximal portion <NUM>, such that intermediate wall <NUM> may have a smaller cross-sectional dimension at an end adjacent to distal portion <NUM> than an opposing end adjacent to proximal portion <NUM>. Stated differently, wall <NUM> may define a tapered surface and/or portion of filter <NUM>, and may have a substantially funnel or conical shape, similar to filters <NUM>, <NUM>, <NUM>, <NUM> shown and described above.

An inner surface of wall <NUM> may define a channel, which may receive agent <NUM>. An angle between the inner surface of wall <NUM> may be greater than an angle of repose of agent <NUM> (e.g., the angle may be steeper than the angle of repose). Accordingly, agent <NUM> may flow freely along wall <NUM> due to a force of gravity. An inner surface of distal portion <NUM> may extend along a plane that is substantially parallel to a longitudinal axis of filter <NUM>. Distal portion <NUM> may have a tubular shape, with substantially constant inner and outer diameters. Distal portion <NUM> may further include an opening at a distal end of distal portion <NUM>, with the opening having a substantially similar diameter as that of the inner diameter of distal portion <NUM>. The opening is in fluid communication with the channel of filter <NUM>.

Filter <NUM> may be sintered (made via a sintering process) with a plurality of pores <NUM> formed through and within wall <NUM>, proximal portion <NUM>, and distal portion <NUM>. The plurality of pores <NUM> may be formed about an entire perimeter of, and within all of, wall <NUM>, proximal portion <NUM>, and distal portion <NUM>. In an embodiment, a size, shape, and/or distribution of the plurality of pores <NUM> may be substantially uniform relative to one another. In other embodiments, the plurality of pores <NUM> may have varying sizes, shapes, and/or spatial distribution relative to one another along and/or within one or more of wall <NUM>, proximal portion <NUM>, and/or distal portion <NUM>. In some embodiments, filter <NUM> may be sintered, formed of a porous metal, formed of a lattice printed material, and more. By providing a sintered and/or porous filter, it should be appreciated that a fluidization consistency may be increased, and potential clogging caused by agent <NUM> may be reduced.

In further embodiments, as seen in <FIG>, a filter <NUM> may include a wall <NUM> disposed between a proximal portion <NUM> and a distal portion <NUM> with a plurality of pores <NUM> formed along and within at least a portion of wall <NUM> and distal portion <NUM>. In the embodiment, a porous portion of filter <NUM> defined by the plurality of pores <NUM> may be formed through wall <NUM> along an end adjacent to distal portion <NUM>, such as, for example, along a side surface of wall <NUM>. It should be appreciated that a size, shape, and/or location of the porous portion and its plurality of pores <NUM> may determine a delivery rate of agent <NUM> from filter <NUM>. In the embodiment of <FIG>, all portions of filter <NUM>, other than the porous portion of pores <NUM>, is solid, without pores, so that gas, fluid, or agent is unable to pass through. As shown and described in further detail herein, a size, location, and/or shape of the porous portion may provide varying fluidization performance capabilities for the filter, such as an average delivery rate of an agent from the filter.

As seen in <FIG>, the porous portion comprising a plurality of pores may be positioned along and/or within various sides and/or portions of the filter. Further, the porous portion may have various suitable sizes, shapes, heights, surface areas, and/or dimensions relative to the one or more sides and/or other portions of the filter. It should be appreciated that the filters shown in <FIG> are substantially similar to filter <NUM>, such that substantially similar reference numerals are used to identify like components. The examples shown and described below were tested in simulated agent delivery conditions to compare the performance of the various designs. Other than the differences in sizes, shapes, and positions of the porous portions of the exemplary filters, environmental parameters influencing the operation and/or performance of the various exemplary filters were controlled when determining an average, minimum, and/or maximum agent delivery rate of each filter. For example, in determining the average, maximum, and minimum delivery rates described in detail below for each of the exemplary filters, one or more of a gas delivery rate (e.g., at <NUM> standard liters per minute, SLPM), a geometry of the filters, a particulate size of the powdered agent, and/or a type of the powdered agent were controlled across each of the exemplary filters.

For example, <FIG> shows a filter 720A having a porous portion defined by a plurality of pores 728A extending along and/or within a portion of wall 722A and a distal portion 728A of filter 720A. For example, the plurality of pores 728A may be extend about half a circumference of wall 722A and distal portion 726A. Stated differently, pores 728A may be formed about <NUM> degrees of an outer circumference of wall 722A and distal portion 726A. In the example, the plurality of pores 728A may be positioned along and/or within at least a portion of wall 722A and distal portion 726A, and pores 728A may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM>, inches squared) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728A may have a height (longitudinal length) defined from a distal end of distal portion 726A ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722A and distal portion 726A including pores 728A may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>. It should be understood that the remaining portions and/or sides of filter 720A that exclude the porous portion may be formed of a solid (e.g., impermeable) surface devoid of any pores. Accordingly, agent <NUM> and/or a pressurized gas may be inhibited from flowing through the remaining portions and/or sides of filter 720A that have a solid configuration.

<FIG> shows another filter 720B having a porous portion defined by a plurality of pores 728B extending along and within a portion of only an intermediate wall 722B of filter 720B (only within the conical portion of filter <NUM>). For example, pores 728B may extend about one-eighth of a circumference of wall 722B. Stated differently, pores 728B may be formed about <NUM> degrees of an outer circumference of wall 722B. In the example, the plurality of pores 728B may be positioned along and within at least one side of wall 722B, and pores 728B may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728B may have a height (longitudinal length) defined from a distal (bottom) end of the porous portion ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722B including pores 728B may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>. It should be understood that the remaining portions and/or sides of filter 720B that exclude the porous portion may be formed of a solid (e.g., impermeable) surface devoid of any pores. Accordingly, agent <NUM> and/or a pressurized gas may be inhibited from flowing through the remaining portions and/or sides of filter 720B that have a solid configuration.

<FIG> shows another filter 720C having a porous portion defined by a plurality of pores 728C extending along and within a portion of an intermediate wall 722C and a distal portion 726C of filter 720C. For example, pores 728C may extend about a quarter of a circumference of wall 722C and distal portion 726C. Stated differently, pores 728C may be formed about <NUM> degrees of an outer circumference of wall 722C and distal portion 726C. In the example, the plurality of pores 728C may be positioned along and within at least one side of wall 722C and distal portion 726C, and pores 728C may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM> ,inches squared) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728C may have a height (longitudinal length) defined from a distal end of distal portion 726C ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722C and distal portion 726C including pores 728C may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>.

In another example, pores 728C may extend about one-eighth of a circumference of wall 722C and distal portion 726C. Stated differently, pores 728C may be formed about <NUM> degrees of the outer circumference of wall 722C and distal portion 726C. Pores 728C may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM>, inches squared) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728C may have a height (longitudinal length) defined from a distal end of distal portion 726C ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722C and distal portion 726C including pores 728C may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>.

In a further example, pores 728C may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM>, inches squared) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728C may have a height (longitudinal length) defined from a distal end of distal portion 726C ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722C and distal portion 726C with the plurality of pores 728C may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>.

It should be understood that the remaining portions and/or sides of filter 720C that exclude the porous portion may be formed of a solid (e.g., impermeable) surface devoid of any pores. Accordingly, agent <NUM> and/or a pressurized gas may be inhibited from flowing through the remaining portions and/or sides of filter 720C that have a solid configuration.

<FIG> shows another filter 720D having a porous portion defined by a plurality of pores 728D extending along and within a portion of only an intermediate wall 722D (only within the conical portion) of filter 720D. For example, pores 728D may extend about a quarter of a circumference of wall 722D. Stated differently, pores 728D may be formed about <NUM> degrees of an outer circumference of wall 722D. In the example, the plurality of pores 728D may be positioned along and within at least one side of wall 722D, and pores 728D may define an internal surface area ranging from about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), such as <NUM><NUM> (<NUM> in<NUM>). Pores 728D may have a height (longitudinal length) defined from a distal end of distal portion 726D ranging from about <NUM> (<NUM> in, inches) to <NUM> (<NUM> in), such as <NUM> (<NUM> in). The portion of wall 722D including pores 728D may be sized and/or shaped to control an average delivery rate of agent <NUM> at about <NUM>/s, with a minimum delivery rate of about <NUM>/s, a maximum delivery rate of about <NUM>/s, and a standard deviation of about <NUM>. It should be understood that the remaining portions and/or sides of filter 720D that exclude the porous portion may be formed of a solid (e.g., impermeable) surface devoid of any pores. Accordingly, agent <NUM> and/or a pressurized gas may be inhibited from flowing through the remaining portions and/or sides of filter 720D that have a solid configuration.

In some embodiments, a filter may include multiple discrete porous portions, including any combination of the porous portions shown and described in <FIG>. For example, an annular array of porous portions may be evenly or unevenly spaced about the circumference of the walls of a filter.

As seen in <FIG>, a size (e.g., height, surface area, circumference, etc.), shape, and position of the porous portion of the filter may determine a delivery rate of agent <NUM>. It should be understood that the delivery rate of agent through the filter may be proportionate to or otherwise correlated with the size, shape, and/or position of the porous portion. Accordingly, the filter may be configured to deliver the agent <NUM> at higher delivery rates when the porous portion has a greater size and/or shape, for example. Further, the delivery rate of the filter may be increased when the porous portion is positioned along and/or within at least the intermediate wall (the conical portion), as compared to the distal portion. All else equal, having a greater amount of the porous portion in the intermediate wall increases a delivery rate of agent.

Agent <NUM> may include particles that have various shapes, including shard shapes, or substantially spherical (bead) shapes. Both shard and bead (substantially spherical) shaped particles may be fluidized, at a range of densities of the particles, as described below. The data described below may result from a fluid flow of <NUM> standard liters per minute (SLPM).

In one example, a semi-cohesive agent <NUM> may have a particle density of approximately <NUM> grams per cubic centimeter. Where the semi-cohesive particles are shard-shaped or substantially spherical and range in size from approximately <NUM> microns to approximately <NUM> microns, with an exit orifice size of <NUM> (<NUM> inches), a delivery rate may be approximately <NUM> grams per second. Where the semi-cohesive particles are shard-shaped or substantially spherical and range in size from approximately <NUM> microns to approximately <NUM> microns, with an exit orifice size of approximately <NUM> (<NUM> inches), a delivery rate may be approximately <NUM> grams per second to approximately <NUM> grams per second. Alternatively, shard-shaped particles with a size of approximately <NUM> microns-<NUM> microns may be used with an exit orifice size of approximately <NUM> (<NUM>) inches.

In another example, an agent <NUM> with a glass bead type of particle may have a particle density of approximately <NUM> grams per cubic centimeter and a substantially spherical shape. Where the particles have a size between approximately <NUM> microns and approximately <NUM> microns, and where an exit orifice has a size of approximately <NUM> (<NUM> inches), a delivery rate may be approximately <NUM> grams per second. Where the particles have a size between approximately <NUM> microns and approximately <NUM> microns, and where an exit orifice has a size of approximately <NUM> (<NUM> inches), a delivery rate may be approximately <NUM> grams per second. Where the particles have a size between approximately <NUM> microns and approximately <NUM> microns, and where an exit orifice has a size of approximately <NUM> (<NUM> inches), a delivery rate may be approximately <NUM> grams per second. Combinations of the particle sizes and delivery rates above may be used. For example, an orifice size of approximately <NUM> (<NUM> inches) may be used with particle sizes between approximately <NUM> and approximately <NUM> microns, or between approximately <NUM> and approximately <NUM> microns, to achieve flow rates of approximately <NUM> grams per second, approximately <NUM> grams per second, or approximately <NUM> grams per second. In other examples, an orifice size of approximately <NUM> (<NUM> inches) may be used with particle sizes between approximately <NUM> and approximately <NUM> microns, or between approximately <NUM> and approximately <NUM> microns, to achieve flow rates of approximately <NUM> grams per second, approximately <NUM> grams per second, or approximately <NUM> grams per second.

Claim 1:
A device (<NUM>, <NUM>, <NUM>, <NUM>) for delivering an agent (<NUM>), comprising:
a housing (<NUM>, <NUM>, <NUM>, <NUM>) defining an enclosure (<NUM>, <NUM>), wherein the housing is configured to store an agent;
an inlet (<NUM>), in fluid communication with the enclosure, for receiving a flow of pressurized fluid;
an outlet (<NUM>, <NUM>) in fluid communication with the enclosure;
a filter (<NUM>, <NUM>', <NUM>", <NUM>, <NUM>, <NUM>, <NUM>, 720A-D) disposed within the enclosure, wherein a wall (<NUM>, <NUM>, <NUM>) of the filter includes a plurality of pores (<NUM>, <NUM>, 728A-D), wherein the pores are configured such that the fluid is permitted to pass through the pores into a channel (<NUM>, <NUM>, <NUM>) defined by an inner surface of the wall; and
an actuation member disposed within the enclosure, wherein the actuation member is configured to transition between a first configuration, in which portions of the agent disposed proximally to the actuation member are prevented from passing distally of the actuation member, and a second configuration, in which portions of the agent disposed proximally of the actuation member are capable of passing distally of the actuation member,
wherein the actuation member includes a rotatable shaft (<NUM>, <NUM>, <NUM>), wherein a longitudinal axis of the shaft is transverse to a longitudinal axis of the enclosure, wherein the fluid is permitted to pass through the outlet in both the first configuration and the second configuration, wherein, upon the shaft having transitioned from the second configuration to the first configuration, the agent is no longer capable of flowing through the outlet, but the fluid can continue to flow from the inlet through the outlet to purge the device.