Wiper seal for piston of dispensing syringe

Abstract

The present disclosure relates to a piston configured for use with a dispensing syringe, and a dispensing syringe having the piston. The piston has a body configured to be slidably positioned within an internal reservoir of a dispensing syringe. The body defines a wall circumferentially surrounding the piston. The piston also has a wiper seal extending circumferentially outwardly from the wall. The wiper seal defines a lip, a first portion, a second portion, and a junction connecting the first portion and the second portion. The second portion extends outwardly from the junction, away from the body, toward the lip.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 311,258, filed February 17, 2022, the disclosure of which is incorporated by reference herein.

[0002] [Technical field] The present disclosure relates generally to the field of dispensing liquid materials, and more specifically to wiper seals for pistons that reduce piston bounce and improve deposit consistency. [Background technology]

[0003] In many industries, various types of dispensers are used to deposit liquids, such as adhesives, conformal coating materials, solder paste, solder flux, and / or other similar materials, onto substrates during assembly processes. One type of liquid dispenser is a syringe-type dispenser, which may include a dispenser body defining a barrel reservoir for holding a supply of liquid material to be dispensed. A dispensing tip may be coupled to the syringe at one end, and the syringe may be in fluid communication with the reservoir at the other end. A piston may be movably disposed within the reservoir to pressurize the liquid in the reservoir, thereby dispensing a small amount of liquid from the dispensing tip onto the substrate.

[0004] Many industrial applications require liquid to be dispensed in precise amounts and to precise locations. To this end, a liquid dispenser may include an actuator for moving a piston within a reservoir in a controllable and predictable manner. For example, a pneumatic actuator may apply compressed gas, such as air, to the piston to move the piston and dispense liquid from the dispenser. Other types of actuators, such as linear actuators, may also be utilized to control the movement of the piston within the reservoir.

[0005] Dispensers may be susceptible to a phenomenon known as "piston bounce." Piston bounce may refer to the accumulation of trapped gas between the piston and the liquid. When the piston is actuated, it may lurk or "bounce" on the trapped gas before contacting the liquid in the dispenser. Piston bounce may cause liquid to remain on the reservoir walls, the piston to move to the top of the reservoir, or air to be undesirably mixed into the fluid. These effects of piston bounce can degrade the performance of a liquid dispenser and can range from minor inconsistencies in the dispensed liquid to tunneling of the liquid within the liquid dispenser. The latter may require disposal of the remaining liquid.

[0006] Conventional solutions to improve the performance of such liquid dispensers often attempt to balance piston bounce and liquid waste. Specifically, the piston may include or at least partially define passages, such as vents, microvents, channels, and / or increased clearances, to direct trapped gas from the liquid, past the piston, and into the surrounding environment. Microvents may allow air that has left the fluid to pass through the piston, but fluid may clog / seal the microvent, thereby preventing the fluid from passing through the piston. While these passages are relatively effective at reducing piston bounce, they tend to expel liquid, resulting in significant waste.

[0007] A need exists for a liquid dispensing syringe that effectively dispenses liquid while addressing the problems discussed above, and a method for reducing piston bounce. Summary of the Invention

[0008] These needs are met to a large extent by a piston (of the present invention) configured for use with a dispensing syringe. The piston includes a body configured to be slidably positioned within an internal reservoir of a dispensing syringe, the body defining a wall circumferentially surrounding the piston. The piston also includes a wiper seal extending circumferentially outwardly from the wall, the wiper seal defining a lip, a first portion, a second portion, and a junction connecting the first portion and the second portion. The second portion extends outwardly from the junction, away from the body, toward the lip.

[0009] Implementations may include one or more of the following features: In a relaxed state, the second portion may extend outwardly from the junction, away from the body, at an angle relative to an axis extending parallel to a longitudinal extension of the piston and passing through the junction. The angle may be greater than 0°. The angle may be greater than 4°. The angle may be between 4° and 10°. The angle may be between 0° and 45°. The first portion may taper from the junction toward the wall. The junction may be radially shaped with a center of curvature disposed toward the body. The wiper seal may be configured to provide a fluid-tight seal with an inner surface of a barrel of the dispensing syringe to inhibit liquid from flowing past the wiper seal.

[0010] One general aspect includes a dispensing syringe with a barrel defining an interior surface and an internal reservoir. The syringe also includes a piston slidably disposed within the internal reservoir. The piston may have a body defining a wall circumferentially surrounding the piston and a wiper seal extending circumferentially outwardly from the wall. The wiper seal defines a lip, a first portion, a second portion, and a junction connecting the first portion and the second portion. The second portion extends outwardly from the junction, away from the body, and toward the lip. An interface length of the second portion of the wiper seal contacts the interior surface of the barrel to form a fluid-tight seal.

[0011] Implementations may include one or more of the following features. The interface length of the second portion of the wiper seal that contacts the inner surface of the barrel may be less than 2 / 3 of the total length of the second portion. The total length of the second portion minus the interface length may be such that the remaining length of the second portion does not contact the inner surface of the barrel. The interface and the first portion may not contact the inner surface of the barrel. The wiper seal may have a material that is less stiff than a material of the barrel, and the wiper seal may be disposed in a compressed state within the barrel. The piston may be removable from the barrel and may return to a relaxed state when removed from the wiper seal. In the relaxed state, the second portion may extend outwardly from the interface and away from the body at an angle relative to an axis that extends parallel to a longitudinal extension of the piston and passes through the interface. The angle may be greater than 4°. The angle may be between 4° and 10°. The first portion may be tapered from the junction towards the wall. The junction may be radially formed with a centre of curvature disposed towards the body.

[0012] Various additional objects, advantages and features of the present disclosure will be understood by considering the following detailed description of the illustrative embodiments in conjunction with the accompanying drawings, in which: The following detailed description is better understood when read in conjunction with the accompanying drawings, in which: For purposes of illustration, examples are shown in the drawings, but the subject matter is not limited to the specific elements and equipment disclosed. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of an exemplary dispensing syringe according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is an exploded perspective view of the dispensing syringe of FIG. [Figure 3A] 3A is a cross-sectional view showing the piston before insertion into the syringe barrel of FIG. 1. FIG. [Figure 3B]FIG. 3B is an enlarged cross-sectional view similar to FIG. 3A. [Figure 3C] FIG. 3C is an enlarged cross-sectional view showing the placement of a piston relative to liquid within the syringe barrel of FIG. 3A. [Figure 3D] FIG. 3D is an enlarged cross-sectional view of the piston and syringe barrel of FIG. 3A when pressurized gas is used. [Figure 3E] FIG. 3E is an enlarged cross-sectional view of the circled portion of the piston of FIG. 3A when the wiper seal is in a relaxed state. [Figure 3F] FIG. 3F is an enlarged cross-sectional view of the circled portion of the piston of FIG. 3D when the wiper seal is in compression within the barrel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Aspects of the present disclosure are directed to a piston for a dispensing syringe and a dispensing syringe including the piston. The piston may include a wiper seal having a geometry that reduces piston bounce to improve dispensing consistency. For example, the wiper seal may extend circumferentially around the body of the piston outwardly from the piston. The wiper seal may define a tip, a first portion, a second portion, and a joint between the first and second portions. The second portion of the wiper seal may extend outwardly from the joint away from the body of the piston toward the tip. With this arrangement, when the piston is slidably disposed within the barrel of the dispensing syringe, only a portion of the second portion of the wiper seal, e.g., less than two-thirds, of the total length of the wiper seal contacts the barrel to form a fluid-tight seal. The wiper seal may be configured such that the remainder of the total length of the second portion of the wiper seal, the joint, and some or all of the first portion do not contact the barrel. This may reduce the surface area of ​​the wiper seal that contacts the barrel compared to traditional wiper seals, allowing trapped gas to pass through the seal more easily while still maintaining a fluid-tight seal between the piston and barrel. Pistons employing wiper seal geometries according to aspects of the present disclosure may reduce or eliminate piston bounce, improving dispensing consistency. These and other aspects of the present disclosure are described in further detail below with reference to Figures 1-3F.

[0015] 1-3F show several embodiments of an example dispensing syringe 10 and piston 20 of the present disclosure. FIGS. 1 and 2 show a perspective view and an exploded perspective view, respectively, of the dispensing syringe 10. FIG. 3A shows a cross-sectional view of the dispensing syringe 10 with the piston 20 removed from the dispensing syringe 10. FIG. 3B shows an enlarged cross-sectional view of the top of the dispensing syringe 10 with the piston 20 removed from the dispensing syringe 10. FIG. 3C shows an enlarged cross-sectional view of the top of the dispensing syringe 10 with the piston 20 slidably disposed within the dispensing syringe 10. FIG. 3D shows an enlarged cross-sectional view of the top of the dispensing syringe 10 with the piston 20 slidably disposed within the dispensing syringe 10 and fully engaged with the dispensing fluid. FIG. 3E shows an enlarged view of the piston 20 in a relaxed state, in the area circled in FIG. 3A. FIG. 3F shows a close-up view of piston 20 in a compressed state, of the circled area of ​​FIG. 3D.

[0016] The dispensing syringe 10 may include a generally elongated barrel 12 having a first end 14 for dispensing a liquid material and a second end 16 opposite the first end 14. The barrel 12 may define an internal reservoir 18 (e.g., shown in FIG. 3A ) for containing the liquid material to be dispensed from the first end 14. The dispensing syringe 10 may include a piston 20 having a body 21 slidably disposed within the internal reservoir 18 and slidably movable between the first end 14 and the second end 16 such that the liquid material is dispensed from the first end 14 when the piston 20 moves in a direction toward the first end 14. The dispensing syringe 10 may include a dispensing tip 22 removably coupled to the first end 14 of the barrel 12 and in communication with the internal reservoir 18 such that the liquid material may be dispensed from an outlet 24 of the dispensing tip 22. According to one exemplary embodiment, barrel 12 may be sized to contain 55 cc of liquid, although it will be understood that barrel 12 may be of any size to contain a desired amount of liquid. Additionally, larger syringe barrels may be referred to as "cartridges" or "cartridge barrels," although the terms "syringe" and "cartridge" in this regard are not intended to limit the disclosure to any particular capacity or barrel.

[0017] The first end 14 of the barrel 12 may include a first connector 26 configured to receive a corresponding second connector 28 on the dispensing tip 22 such that the dispensing tip 22 may be coupled to the first end 14 of the barrel 12. The second end 16 of the barrel 12 may include an opening 30 (e.g., as shown in FIG. 3A ) and may have a radially outwardly extending flange 32. The flange 32 may include a pair of oppositely disposed tabs or ears 34, 36 that may extend radially outwardly in opposite directions from the flange 32 to facilitate securing an adapter 38 for coupling the dispensing syringe 10 to an actuator, such as a source of pressurized gas 39. Portions of the barrel 12, dispensing tip 22, first connector 26, adapter 38, and piston 20 are described in further detail in U.S. Pat. No. 9,958,067, the disclosure of which is incorporated by reference herein in its entirety.

[0018] An exemplary embodiment of the piston 20 may include a distal end 40 configured to force (push) a liquid material 42 (e.g., as shown in FIG. 3B ) through the first end 14 of the barrel 12 to the dispensing tip 22. With reference to FIG. 2 , the distal end 40 of the piston 20 may mate with the second end 16 of the barrel 12 to force (push) the liquid material 42 to the dispensing tip 22. A proximal end 44 of the piston 20 opposite the distal end 40 may be exposed to a pressurized gas 39, which may actuate the piston 20 in a direction from the second end 16 of the barrel 12 toward the first end 14 of the barrel 12. For example, the pressurized gas 39 may be pressurized air, as provided in a typical business or manufacturing environment. Alternatively, the piston 20 may be actuated manually, by any other actuator, or the like.

[0019] 3A, the piston 20 may include a first wiper seal 48 that may extend radially outward from the piston 20 and may engage an inner surface 50 of the barrel 12 to seal the first wiper seal 48 against the inner surface 50. The first wiper seal 48 may be positioned on the piston 20 between the distal end 40 and the proximal end 44. In one embodiment, the first wiper seal 48 may be a flange or skirt and may extend circumferentially around the body 21 of the piston 20. The first wiper seal 48 may have an interference fit with the inner surface 50 of the barrel 12, which may ensure that the first wiper seal 48 conforms to the inner surface 50 of the barrel 12 and may radially compensate for any geometric irregularities of the first wiper seal 48 and / or the inner surface 50 of the barrel 12. In this regard, the first wiper seal 48 may be structured and / or configured to have an interference fit with the inner surface 50 of the barrel 12, thereby ensuring that the first wiper seal 48 conforms to the inner surface 50 of the barrel 12 and radially compensating for any geometric irregularities of the first wiper seal 48 and / or the inner surface 50 of the barrel 12.

[0020] As shown in the enlarged resolution of FIGS. 3E and 3F, the first wiper seal 48 can include a first lip 52, a first portion 72, a second portion 76, and a junction 74 connectable between the first portion 72 and the second portion 76. The first portion 72 can taper from the junction 74 to the wall 66 of the piston 20. The junction 74 can be radially shaped and have a center of curvature disposed toward the body 21 of the piston 20. The second portion 76 can extend outwardly from the junction 74 and away from the body 21 to the first lip 52. For example, as shown in FIG. 3E, when the piston 20 is in a relaxed state outside the barrel 12, the second portion 76 can extend outwardly from the junction 74 away from the body 21 at an angle α with respect to an axis A that runs parallel to the longitudinal direction of the piston 20 and passes through the junction 74. The magnitude of the angle α can be selected based on material properties of the first wiper seal 48, such as stiffness, and / or the difference between the first outer diameter dl of the first lip 52 and the inner diameter di of the internal reservoir 18. In some embodiments, the angle α can be greater than 0°, greater than 4°, greater than 6°, greater than 8°, greater than 10°, greater than 12°, greater than 14°, greater than 16°, greater than 18°, greater than 20°, greater than 24°, greater than 28°, and / or greater than 32°. In some embodiments, the angle α can be between 0° and 45°, between 4° and 10°, between 10° and 15°, or between 15° and 25°. In some embodiments, angle α may be less than 4°, less than 6°, less than 8°, less than 10°, less than 12°, less than 14°, less than 16°, less than 18°, less than 20°, less than 24°, less than 28°, and / or less than 32°. In some aspects, first portion 72 extends radially outward from wall 66 at an angle relative to axis A, which extends parallel to the longitudinal direction of piston 20 and passes through junction 74, that is greater than angle α.In some aspects, first portion 72 extends radially outward from wall 66 at an angle less than angle α with respect to axis A, which extends parallel to the longitudinal axis of piston 20 and passes through junction 74. In some aspects, first portion 72 can have a generally planar outer surface between wall 66 and junction 74. In some aspects, second portion 76 can have a generally planar outer surface between junction 74 and first lip 52.

[0021] 3F, the piston 20 may be slidably disposed within the barrel 12 of the dispensing syringe 10 and the first wiper seal 48 may be compressed inwardly to a compressed state. In the compressed state, the first wiper seal 48 may engage (act) with an inner surface 50 of the barrel 12. For example, the first wiper seal 48 may be formed of a material that is less rigid than the material forming the barrel's inner surface 50 such that the first wiper seal 48 is compressed to the compressed state when slidably disposed within the barrel 12.

[0022] Due to the geometry of the first wiper seal 48, i.e., the aforementioned structural relationships between the first lip 52, the first portion 72, the interface 74, and / or the second portion 76, the first wiper seal 48 may contact the inner surface 50 of the barrel 12 at an interface 78 defined by only a portion of the surface area of ​​the first wiper seal 48. For example, in some embodiments, only the first lip 52 and the second portion 76 of the first wiper seal 48 form the interface 78 with the inner surface 50 of the barrel 12. That is, the interface 74 and the first portion 72 do not contact the inner surface 50 of the barrel 12. In some embodiments, a portion of the second portion 76 also does not contact the inner surface 50 of the barrel 12. For example, the second portion 76 may have an interface length that contacts the inner surface 50 of the barrel 12, with the remainder of the entire length of the second portion 76 not contacting the inner surface 50 of the barrel 12. In some embodiments, the interface length may be less than two-thirds of the entire length of the second portion 76. In some embodiments, the interface length may be less than half the total length of the second portion 76. In some embodiments, the interface length may be 10%, 20%, 30%, 40%, 50%, 60%, and / or 70% of the total length of the second portion 76. In some embodiments, the interface length may be 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, and / or 60%-70% of the total length of the second portion 76. Because only a portion of the first wiper seal 48 may contact the inner surface 50 of the barrel 12, trapped gas 70 may more easily escape through the first wiper seal 48, and piston bounce may be reduced or eliminated. This was an unexpected result and is a result of the configuration of at least the first wiper seal 48, first lip 52, first portion 72, second portion 76, and / or interface 74 of the present disclosure. Additionally, the geometry of first wiper seal 48 provides a fluid-tight seal with interior surface 50 of barrel 12. These features combine to improve the consistency of dispensing from dispensing syringe 10.

[0023] Additionally, the piston 20 may include a second wiper seal 54 that may be positioned at the proximal end 44 of the piston 20. The second wiper seal 54 may be generally formed of the same material as the first wiper seal 48 and may have a second lip 56 engageable with the inner surface 50 of the barrel 12. In some embodiments (not shown), the second wiper seal 54 may or may not be provided with the first portion, second portion, and interface described above with respect to the first wiper seal 48. With respect to the use of the terms "distal" and "proximal," it will be understood that such directions and / or positions are intended to describe relative longitudinal positions along an exemplary embodiment of the dispensing syringe 10. These terms or any other spatial references are not intended to limit the present disclosure to any of the exemplary embodiments described herein.

[0024] As shown in FIGS. 3A and 3B, the inner surface 50 of the internal reservoir 18 may be generally cylindrical and may have an inner diameter di. The first lip 52 and the second lip 56 may have a first outer diameter d1 and a second outer diameter d2, respectively, in a relaxed state when the piston 20 is disposed outside the internal reservoir 18. According to one embodiment, in the relaxed state, the first diameter d1 and the second diameter d2 may each be larger than the inner diameter d1 before being inserted into the internal reservoir 18. Thus, as shown by arrow 60, when the piston 20 is inserted into the internal reservoir 18, at least the first lip 52 and the second lip 56 may be compressed into a compressed state and may form an interference fit with the inner surface 50 of the barrel. Furthermore, the second diameter d2 may be at least as large as the first diameter d1. According to one embodiment, the second diameter d2 may be larger than the first diameter d1 as shown in the relaxed state.

[0025] The piston 20 may include a generally rigid portion 62 and an elastic portion 64. In some aspects, the generally rigid portion 62 is more rigid than the elastic portion 64. The first wiper seal 48 may be positioned on the generally rigid portion 62 of the piston 20, and the second wiper seal 54 may be positioned on the elastic portion 64 of the piston 20. The generally rigid portion 62 may maintain the first wiper seal 48 in a generally constant shape and size, regardless of whether pressure is applied within the body 21 of the piston 20. In contrast, the elastic portion 64 may elastically deform under the influence of pressure applied within the body 21 and act on the second wiper seal 54. As described herein, the term "elastic" generally means that the elastic portion 64 of the piston 20 is flexible, such that the elastic portion 64 expands under the influence of a force and contracts when the force is removed or reduced. Furthermore, the elastic portion 64 of the piston 20 may be more flexible than the rigid portion 62. The material of construction of piston 20 does not need to be a material that is highly elastic in itself, but can be a flexible material that can be formed to result in piston 20 having one or more relatively rigid portions and one or more relatively flexible elastic portions, as in this example.

[0026] According to one embodiment, the generally rigid portion 62 and the resilient portion 64 may be integrally formed from the same material, such as low density polyethylene. The resilient portion 64 may be created by modifying the geometry of the piston 20 such that the resilient portion 64 is more resilient than the generally rigid portion 62. As shown more clearly in FIG. 3B, the wall 66 of the piston 20 tapers in a proximal direction from the first wiper seal 48 to the second wiper seal 54 to form the resilient portion 64. The wall 66 is thinner than the generally rigid portion 62 and therefore more resilient than the generally rigid portion 62. However, it will be understood that other shapes or various materials may be used alone or in combination to form the generally rigid portion 62 and the resilient portion 64. For example, the piston 20 may be formed from two or more materials having different material properties related to elasticity. In an alternative embodiment, the piston 20 may be provided without the resilient portion 64 and the piston 20 may be configured with a generally consistent geometry from the proximal end 44 to the distal end 40 of the piston 20. In such an embodiment, the resiliency of the piston 20 may be similar from the proximal end 44 to the distal end 40 of the piston 20. In both embodiments, as previously described, the first wiper seal 48 may inhibit the passage of liquid material 42 proximally therethrough, while the second wiper seal 54 may inhibit the passage of pressurized gas 39 distally therethrough. In other words, the first wiper seal 48 seals liquid against the inner surface 50, and the second wiper seal 54 seals fluid against the inner surface 50, at least when the proximal end 44 of the piston 20 is receiving the pressurized gas 39.

[0027] As shown in FIG. 3C, the piston 20 may be inserted into the internal reservoir 18 and abut the liquid material 42, as indicated by arrow 68, with or without the influence of the pressurized gas 39. Gas 70, such as air, trapped between the liquid material 42 and the piston 20 may flow through each of the first wiper seal 48 and the second wiper seal 54, as indicated by the arrows in FIG. 3C, to exit the internal reservoir 18. According to one embodiment, neither the first wiper seal 48 nor the second wiper seal 54 has passages, such as vents, microvents, flow paths, and / or increased clearances, to facilitate the flow of the trapped gas 70 from the internal reservoir 18. Rather, when the volume containing the liquid material 42 in the internal reservoir 18 is reduced, the trapped gas 70 may escape through the first wiper seal 48 and the second wiper seal 54. Alternatively, the first wiper seal 48 may include passages (not shown), such as vents, microvents, flow paths, and / or increased clearances, in combination with the resilient portion 64 to further facilitate the flow of the trapped gas 70. The passages (not shown) provide for the flow of the trapped gas 70, but may generally fill with liquid material 42 when the trapped gas 70 is removed, dynamically sealing the liquid material 42 within the internal reservoir 18. When the trapped gas 70 is generally removed from between the piston 20 and the liquid material 42, the distal end 40 of the piston 20 may be positioned against the liquid material 42 such that the first wiper seal 48 may seal the liquid material 42 within the barrel 12.

[0028] 3D, the pressurized gas 39 may travel distally along the barrel 12 until it is received by the proximal end 44 of the piston 20. The pressurized gas 39 may then act on the piston 20 in two distinct manners. First, the pressurized gas 39 may press the distal end 40 against the liquid material 42, causing the liquid material 42 to be expelled from the dispensing syringe 10. Second, the pressurized gas 39 may be applied to the resilient portion 64, which may expand and press the second wiper seal 54 against the inner surface 50. According to one embodiment, the second wiper seal 54 may be compressed against the inner surface 50. The second wiper seal 54 may expand distally to contact the inner surface 50 with increased pressure and increased surface area to form a fluid seal against the pressurized gas 39. When the flow of pressurized gas 39 stops, the elastic portion 64 may contract and the second wiper seal 54 may contact the inner surface 50 with reduced pressure and reduced surface area, as shown in FIG. 3C. In this regard, the type of seal provided by the second wiper seal 54 may vary depending on the application of the pressurized gas 39. Specifically, the second wiper seal 54 may allow the trapped gas 70 to pass, but may fluidly seal against the pressurized gas 39 while discharging the liquid material 42. Alternatively, according to another embodiment, the elastic portion 64 may press the second wiper seal 54 against the inner surface 50 with increased pressure, but without contacting the inner surface 50 with an increased surface area. For example, the elastic portion 64 may be deformed by the pressurized gas 39, but the second wiper seal 54 may simply press against the inner surface 50 without expanding distally. Thus, alternative embodiments of the second wiper seal 54 may be generally rigid and fluidly seal against the pressurized gas 39 at only increased pressure. In either embodiment, the second wiper seal 54 may inhibit the pressurized gas 39 from inadvertently passing past the first wiper seal 48 between the piston 20 and the liquid material 42. Thus, the distal end 40 is maintained against the liquid material 42 as the piston 20 moves through the internal reservoir 18. Furthermore, one embodiment of the second wiper seal 54 does not include a passage for releasing (venting) the trapped gas 70 along the piston 20 to the surrounding environment.

[0029] In some aspects, the present disclosure provides for a liquid dispensing syringe with a barrel and a piston and a method for reducing piston bounce. This is an unexpected result, which is a result of the structure of at least the first wiper seal 48, the first lip 52, the first portion 72, the second portion 76, and / or the interface 74 of the present disclosure. The barrel defines an internal reservoir having an inner surface. The piston is disposed within the internal reservoir, has a proximal end, and has a resilient portion configured to expand under the influence of a pressurized gas. A circumferentially extending first wiper seal is positioned on the piston. The first wiper seal has a flexible seal wiper with a sealing surface angled to liquid seal against the inner diameter of the barrel parallel and flush with the inner diameter of the barrel when the first wiper seal is contracted to the inner diameter of the barrel.

[0030] In some aspects, the present disclosure provides for an implementation of a piston having a flared wiper for use in contact with a barrel / container that allows air present in the fluid to bypass the wiper but does not allow air outside the wiper to bypass the seal and enter the fluid. This was an unexpected result and is a result of the construction of at least the first wiper seal 48, first lip 52, first portion 72, second portion 76, and / or interface 74 of the present disclosure. Compared to current pistons, the flared surface improves interference with the barrel at the seal point while reducing the force required to move the piston. This was an unexpected result and is a result of the construction of at least the first wiper seal 48, first lip 52, first portion 72, second portion 76, and / or interface 74 of the present disclosure. This combination of properties allows air to pass through the wiper but prevents liquid from passing, allowing air trapped in the fluid to vent past the piston during normal operation. This was an unexpected result and is a result of the configuration of at least the first wiper seal 48, the first lip 52, the first portion 72, the second portion 76, and / or the interface 74 of the present disclosure.

[0031] In some aspects, the present disclosure includes manufacturing methods where the flexible nature of the plastic at high temperatures causes the wipers to smear, deform, and / or other similar events upon ejection. The combination of design geometry, the tendency of polyethylene to stick, and the surface texture of the wipers results in a repeatable flare as described and illustrated herein.

[0032] In some embodiments of the present disclosure, the various features disclosed provide improved piston performance, which is an unexpected result as a result of the configuration of at least the first wiper seal 48, the first lip 52, the first portion 72, the second portion 76, and / or the interface 74 of the present disclosure. In some embodiments of the present disclosure, the various features disclosed provide reduced bounce, which is an unexpected result as a result of the configuration of at least the first wiper seal 48, the first lip 52, the first portion 72, the second portion 76, and / or the interface 74 of the present disclosure.

[0033] In some embodiments of the present disclosure, various disclosed features provide good wall wipe. This was an unexpected result and is a result of the construction of at least the first wiper seal 48, first lip 52, first portion 72, second portion 76, and / or interface 74 of the present disclosure. In tests using highly splashy fluids, approximately 2 / 3 of the current pistons exhibited splash. In the same tests, the flared pistons exhibited little to no splash. This was an unexpected result and is a result of the construction of at least the first wiper seal 48, first lip 52, first portion 72, second portion 76, and / or interface 74.

[0034] It will be understood that the foregoing description provides an example of the machine of the present disclosure. However, it is envisioned that other implementations of the present disclosure may differ in detail from the foregoing example. All references to the present disclosure or its examples are intended to refer to the particular examples described at the time, and are not intended to imply any limitation with respect to the scope of the present disclosure more generally. Any references to particular features or to disparagement are intended to indicate a lack of preference for those features, and are not intended to exclude those features entirely from the scope of the present disclosure, unless otherwise expressly stated. All methods described herein may be performed in any suitable order, unless otherwise expressly stated herein or otherwise clearly contradicted by context.

Claims

1. 1. A piston configured for use with a dispensing syringe, comprising: a body configured to be slidably positioned within an internal reservoir of the dispensing syringe, the body defining a wall circumferentially surrounding the piston; a wiper seal extending circumferentially outward from the wall, the wiper seal defining a lip, a first portion, a second portion, and a joint connecting the first portion and the second portion; Equipped with In a relaxed state, the second portion extends outward from the junction, away from the body, toward the lip at an angle greater than 0° relative to an axis extending parallel to the longitudinal extension of the piston and passing through the junction. A piston characterized by:

2. The angle is greater than 4° 2. The piston of claim 1.

3. The angle is between 4° and 10° 2. The piston of claim 1.

4. The angle is between 0° and 45° 2. The piston of claim 1.

5. The first portion is configured to taper from the junction toward the wall.

2. The piston of claim 1.

6. The joint is formed radially with a center of curvature disposed toward the main body.

2. The piston of claim 1.

7. The wiper seal defines an interface configured to contact an interior surface of the barrel of the dispensing syringe to provide a fluid-tight seal and inhibit fluid from flowing past the wiper seal.

2. The piston of claim 1.

8. the interface is formed only by the lip and the second portion, and the joint and the first portion do not contact the inner surface of the barrel.

8. The piston of claim 7.

9. a barrel defining an interior surface and an internal reservoir; a piston slidably disposed within the internal reservoir; Equipped with The piston is a body defining a wall circumferentially surrounding the piston; a wiper seal extending circumferentially outward from the wall, the wiper seal defining a lip, a first portion, a second portion, and a joint connecting the first portion and the second portion; It has in a relaxed state, the second portion extends outward from the junction, away from the body, and toward the lip at an angle greater than 0° relative to an axis extending parallel to the longitudinal extension of the piston and passing through the junction; An interface length of the second portion of the wiper seal contacts the interior surface of the barrel to form a fluid-tight seal.

1. A dispensing syringe comprising:

10. The interface length of the second portion of the wiper seal that contacts the inner surface of the barrel is less than two-thirds of the total length of the second portion.

10. The dispensing syringe of claim 9.

11. The remaining length of the second portion, which is the total length of the second portion minus the interface length, does not contact the inner surface of the barrel.

11. The dispensing syringe of claim 10.

12. The joint and the first portion do not contact the inner surface of the barrel.

12. The dispensing syringe of claim 11.

13. Only the lip and the second portion contact the inner surface of the barrel.

13. The dispensing syringe of claim 12.

14. the wiper seal having a material less rigid than a material of the barrel; The wiper seal is disposed in a compressed state within the barrel.

10. The dispensing syringe of claim 9.

15. The piston is removable from the barrel, and the wiper seal is configured to return to a relaxed state when removed from the barrel.

15. The dispensing syringe of claim 14.

16. In a relaxed state, the second portion extends outwardly from the junction and away from the body at an angle relative to an axis extending parallel to the longitudinal extension of the piston and passing through the junction.

16. The dispensing syringe of claim 15.

17. The angle is greater than 4° 17. The dispensing syringe of claim 16.

18. The angle is between 4° and 10° 18. The dispensing syringe of claim 17.

19. The first portion is configured to taper from the junction toward the wall.

10. The dispensing syringe of claim 9.

20. The joint is formed radially with a center of curvature disposed toward the main body.

10. The dispensing syringe of claim 9.

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