Water flosser
Patent Information
- Authority / Receiving Office
- VN · VN
- Patent Type
- Applications
- Current Assignee / Owner
- WATER PIK INC
- Filing Date
- 2024-06-26
- Publication Date
- 2026-06-15
AI Technical Summary
Conventional oral irrigator pumps face manufacturing challenges due to tight tolerance requirements for piston seals, which can lead to leakage and mechanical failure over time.
A piston seal design featuring flexible, elastomeric protrusions and grooves that store lubricant, allowing for efficient sealing and reduced manufacturing tolerances, while maintaining effective fluid containment and piston movement.
The design enhances the manufacturability and sealing efficiency of oral irrigator pumps, reducing leakage and extending the lifespan of the device by using flexible materials and multiple sealing points without compromising pump efficiency.
Abstract
Description
Piston Seal for Oral IrrigatorCross-Reference to Related Applications
[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 523,285, filed June 26, 2023, the disclosure of which is incorporated by reference in its entirety.
[0002] This application also claims the benefit of CN Patent Application No.202311551296.1, filed November 20, 2023, the disclosure of which is incorporated by reference in its entirety.
[0003] This application also claims the benefit of U.S. Provisional Application No. 63 / 606,276, filed December 5, 2023, the disclosure of which is incorporated by reference in its entirety.Technical Field
[0004] The present invention relates to health and personal hygiene equipment and more particularly, to oral irrigators.
[0005] Oral irrigators typically are used to clean a user’s teeth and gums by discharging a pressurized fluid stream into a user’s oral cavity. The fluid impacts the teeth and gums to remove debris. Often, the oral irrigator includes a fluid supply, such as a reservoir, that is fluidly connected by a pump to an oral irrigator tip. A pump then pumps fluid from the reservoir to a tip to be expelled in the user’s oral cavity. Conventional oral irrigator pumps have included a piston that seals against the internal walls of the pump body to prevent fluid from leaking around the piston (e.g., that may damage the motor or other parts). However, such designs typically require tight tolerances to ensure that the piston can still be readily moved within the pump body, which can be difficult to manufacture at scale and may fail over time.
[0006] In one embodiment, an oral irrigator includes a piston and a piston seal, where the piston seal is positioned around the piston. The piston seal also includes a first protrusion and a second protrusion.
[0007] The first and second protrusions may be configured to seal against a pump body to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
[0008] A groove may be defined between the first and second protrusions. The groove may define a grease store to hold lubricant between the piston seal and the pump body.
[0009] The piston seal may be configured to define a grease store to hold lubricant between the piston seal and the piston.
[0010] The piston may include a skirt extending from the seal groove.
[0011] The oral irrigator may include a pump body, with the pump body including the piston seal.
[0012] The oral irrigator may include a second piston seal positioned on an end of the piston.
[0013] In another embodiment, an oral irrigator includes a piston and a piston seal positioned around the piston. The piston seal is positioned to define a grease store to hold lubricant between the piston seal and the piston.
[0014] The piston seal may include a first sealing protrusion and a second sealing protrusion.
[0015] The grease store may be defined between the second sealing protrusion and the piston.
[0016] The first and second sealing protrusions may seal against a pump body to limit fluid from leaking around the piston as the piston moves relative to the pump body.
[0017] A groove may be defined between the first and second sealing protrusions. The groove may define a second grease store to hold lubricant between the piston seal and the pump body.
[0018] The groove may define the grease store to hold the lubricant between the piston seal and a pump body.
[0019] The oral irrigator may include a second piston seal positioned on an end of the piston.
[0020] In another embodiment, an oral irrigator includes a piston, a pump body, and a piston seal including a main body and a pair of protrusions extending from the main body to seal the piston to the pump body.
[0021] The first protrusion and the second protrusion may seal against the pump body to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
[0022] The first protrusion and the second protrusion may seal against the piston to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
[0023] A groove may be defined between the first protrusion and the second protrusion, the groove defining a grease store to hold lubricant between the piston seal and the pump body.
[0024] The piston may include a skirt and a deflection cavity allowing the skirt to flex inwardly.
[0025] The oral irrigator may include a second piston seal positioned on an end of the piston.
[0026] In another embodiment, an oral irrigator includes a pump body, a piston including a seal groove, and a piston seal received in the seal groove. The piston seal includes a pair of protrusions separated by a groove, the pair of protrusions configured to sealingly engage the pump body.
[0027] In another embodiment, an oral irrigator includes a piston including a seal groove defined around a circumference of the piston, a first seal positioned within the seal groove, and a second seal separate from the first seal and defining a distal end of the piston.
[0028] In another embodiment, an oral irrigator includes a piston, a pump body including a seal groove, and a piston seal positioned within the seal groove of the pump body and extending to engage the piston.Brief Description of the Drawings
[0029] Fig. 1 is a front view of an oral irrigator.
[0030] Fig. 2 is a front view of a pump assembly and control assembly for an oral irrigator.
[0031] Fig. 3 is a cross-section view of the pump assembly of Fig. 2.
[0032] Fig. 4 is a rear isometric view of a piston assembly for the pump assembly of Fig. 3.
[0033] Fig. 5 is a side elevation view of the piston assembly of Fig. 4.
[0034] Fig. 6 is an isometric view of a piston seal for the piston assembly.
[0035] Fig. 7A is a side elevation view of the piston seal of Fig. 6.
[0036] Fig. 7B is a top plan view of the piston seal of Fig. 6.
[0037] Fig. 7C is a cross-section view of the piston seal taken along line A-A in Fig. 7B.
[0038] Fig. 8A is a cross-section view of the pump assembly of Fig. 2 including another piston assembly.
[0039] Fig. 8B is an enlarged detail view of Fig. 8A.
[0040] Fig. 9 is an isometric view of another piston for a piston assembly.
[0041] Fig. 10 is a side elevation view of the piston of Fig. 9.
[0042] Fig. 11 is an isometric view of another piston seal for a piston assembly.
[0043] Fig. 12A is a top plan view of the piston seal of Fig. 11.
[0044] Fig. 12B is a cross-section view of the piston seal taken along line A-A in Fig. 12A.
[0045] Figs. 13-14 are side elevation views showing different seal orientations in a spaced relationship.
[0046] Figs. 15-16 are isometric views of a piston assembly.
[0047] Fig. 17 is an isometric view of another piston for a piston assembly.
[0048] Fig. 18 is a cross-section view of another piston assembly.Detailed Description of the Invention
[0049] The present disclosure is related to pump assembly for an oral irrigator with an improved piston seal. In one example, the pump assembly includes a piston assembly having a piston driven by a motor and a piston seal received around an outer surface of the piston (e.g., positioned within an annular groove formed on the piston). In one example, the piston seal may be formed of a softer, more flexible material and be configured to define a seal against a wall of the pump body, sealing a bottom of the pump body, e.g., to prevent fluid from leaking around the piston assembly. The piston seal may also include multiple sealing features, e.g., protrusions, that extend from a surface of a seal body to engage the pump body and provide multiple seal points on the pump body interior surfaces, but also may help to prevent the sealing area from being overly wide or otherwise, e.g., allowing a reduced surface area engaging the pump body to enable efficient movement of the piston.
[0050] With reference to Fig. 1, an oral irrigator 100 is disclosed that includes a base 102 that supports a reservoir 104 for holding a fluid (e.g., water or mouthwash). The reservoir 104 is fluidly coupled to a handle 106 that includes a tip 108 (e.g., jet tip, brush head, or the like) for expelling a fluid stream into a user’s oral cavity. One or more controls 110 operate the oral irrigator 100, e.g., turn the oral irrigator 100 on / off and vary the pressure or other fluid characteristics of the fluid exiting the tip 108. For example, the controls 110 may be coupled to a pump assembly that pulls fluid from the reservoir 104 and pumps it to the tip 108.
[0051] With reference to Fig. 2, the oral irrigator 100 may include a pump assembly 112 that includes a pump body 114 and a motor 116 for driving a piston within the pump body 114. The pump assembly 112 may be positioned within the base 102 and coupled to the controls 110, such that the controls 110 can activate the pump assembly 112, as well as vary characteristics of the pump assembly 112 (e.g., change a pressure output by the pump assembly 112). The pump body 114 may be fluidly coupled to the reservoir 104 and may optionally include an inlet port and an outlet port that may include valves (e.g., one way valves, such as reed valves) on either side thereof.
[0052] Fig. 3 is a simplified cross section view of the pump assembly 112 of Fig. 2. Fig. 4 is a bottom perspective view of a piston assembly 119. With reference to Fig. 3, the pump body 114 may include a pump cavity 115 that includes an interior surface where a piston assembly 119 is driven to move therein. The piston assembly 119 may be driven by a connecting arm or rod 118, which may be coupled to the motor 116, such as through one or more linkages or gears. The connecting arm 118 may include a ball end and be partially received within an open end of a piston 120 of the piston assembly 119.
[0053] The piston assembly 119 may include a piston 120 that may be a generally cylindrically shaped member and may have a relatively constant diameter along its length,except for a seal groove 124 that may extend annular (e.g., an annular groove) around the exterior of the piston 120. The seal groove 124 may be defined between a top end of the piston and a position of the connecting arm 118 (once connected to the piston 120). The seal groove 124 may also be configured to receive a piston seal 122 and therefore may have a length and depth configured to allow the piston seal 122 to be fully seated within the seal groove 124 and extend such that the piston seal 122 can contact the pump body 114 interior surface, e.g., be positioned slightly raised past an exterior surface of the piston 120.
[0054] A top end of the piston 120 may form a head or flanged portion 126 that may be oriented towards the inlet and / or outlet of the pump body 114. A connecting cavity 128 may be defined on an open or bottom end of the piston 120 and be configured to receive the connecting arm 118. The connecting cavity 128 may taper or otherwise change in diameter along a length of the piston 120, e.g., may have a first portion that is narrow than a second portion.
[0055] The piston seal 122 may be included with the piston assembly 119. The piston seal 122 may be configured to be positioned on the piston 120, e.g., within the seal groove 124, and seal a space between the exterior of the piston 120 and the interior surface of the pump body 114. The piston seal 122 may be formed of a flexible and / or elastic element, such as rubber or another elastomer and be able to deform to define a sealed connection between two elements, e.g., the pump body 114 and the piston 120. The piston seal 122 may include one or more sealing protrusions, e.g., a single sealing protrusion, a first sealing protrusion 130 and a second sealing protrusion 132, etc. For example, the piston seal 122 may include a dual seal design. In one example, the sealing protrusions 130, 132 may be separated by a groove 134 (e.g., of the piston seal 122). The sealing protrusion 130, 132 may be configured to be raised above the remaining areas of the piston seal and configured to sealingly engage the pump body 114.
[0056] In one example, see, e.g., Fig. 6, the sealing protrusions 130, 132 may include slightly angled walls that extend at an angle upwards from the seal body. The top end of the sealing protrusions 130, 132 may be curved or formed a frustum end for the protrusions, e.g., be planar or relatively planar. The protrusions 130, 132 may have a length that is less than a fourth of a length of the piston seal 120 overall, e.g., may be thin protrusions relative to the piston seal, which helps to increase efficiency of the pump 112.
[0057] In use, the piston seal 120 is positioned within the seal groove 124 of the piston 120 and the piston 120 is connected to the connecting arm 118. As the motor 116 drives the connecting arm 118, the piston assembly 119 moves within the pump body 114. The piston seal 122 and specifically the protrusions 130, 132 seal against the interior surface of the pump body 114 to prevent fluid from leaking around the piston assembly 119, such as to exit the bottom of the pump body 114. The small length of the protrusions 130, 132 define arelatively small sealing area on the pump body 114 so as to not introduce substantial drag on the piston 120.
[0058] Additionally, because the seal 122 is formed separately from the piston 120, the piston 120 can be manufactured at looser tolerances, allowing easier manufacturability and assembly. Further, the multiple sealing protrusions on the seal may allow better sealing than other types of elastomeric designs, without substantially impacting efficiency of the pump.
[0059] Fig. 8A is a simplified cross-section view of the pump assembly 112 including another piston assembly 219. Fig. 8B is an enlarged detail view of Fig. 8A. Except as otherwise described below, the piston assembly 219 may be similar to the piston assembly 119, described above, and thus, any features described above with reference to the piston assembly 119 may be applied to the piston assembly 219. For example, the piston assembly219 may be driven to move in the pump cavity 115 of the pump body 114. In one example, the piston assembly 219 may be driven by the connecting arm 118, such as in a manner as described above.
[0060] Like piston assembly 119, the piston assembly 219 may include a piston 220 of a generally cylindrical shape. A top end of the piston 220 may form a head portion 226 oriented towards the inlet and / or outlet of the pump body 114. A bottom end of the piston220 may define a connecting cavity 228 to receive the connecting arm 118. Like connecting cavity 128, the connecting cavity 228 may taper or otherwise change in diameter along a length of the piston 220, such as to accommodate movement of the connecting arm 118.
[0061] A seal groove 224 may be defined around a circumference of the piston 220, such as extending annularly (e.g., an annular groove) around the exterior of the piston 220. The seal groove 224 may be defined at a position along the length of the piston 220. In one example, the seal groove 224 may be defined between the terminal end of the connecting arm 118 and the top end of the piston 220. The seal groove 224 may be configured to receive a piston seal 222. For example, the seal groove 224 may be sized and shaped to accommodate the piston seal 222 and allow the piston seal 222 to seal against the interior of the pump body 114, as described herein.
[0062] Figs. 9-10 are isometric and side elevation views of the piston 220. Referring to Figs. 8A, 9, and 10, the piston 220 may include a skirt 240 at the distal or top end of the piston 220, such as by the head portion 226. The skirt 240 may be a flexible portion of the piston 220 that deforms to maintain engagement with the interior of the pump body 114. In one example, the skirt 240 may be formed by a thin wall of material extending towards the inlet and / or outlet of the pump body 114. The skirt 240 may extend from the seal groove 224. In one example, a deflection cavity 242 may allow the skirt 240 to flex inwardly.
[0063] As shown, the seal groove 224 may be defined by a first cavity 246 and a second cavity 248. The first cavity 246 may be defined by an annular groove 250. The second cavity248 may be defined by an angled wall 252 tapering inward from the skirt 240 to the annular groove 250. The first and second cavities 146, 148 may accommodate corresponding portions of the piston seal 222, as described more fully below.
[0064] Fig. 11 is an isometric view of the piston seal 222. Fig. 12A is a top plan view of the piston seal 222. Fig. 12B is a cross-section view of the piston seal 222 taken along line A-A in Fig. 12A. The piston seal 222 may include a main body 260. One or more sealing protrusions may extend from the main body 260. For instance, a first sealing protrusion 230 and a second sealing protrusion 232 may extend from the main body 260 to define a dual seal design of the piston seal 222 (e.g., an L-type lip seal). The first and second sealing protrusions 230, 232 may extend outwardly from the main body 260 towards the interior surface of the pump body 114. In one example, at least one of the first sealing protrusion 230 or the second sealing protrusion 232 may angle away from the main body 260. For instance, as shown in Figs. 8A-8B and 12B, the second sealing protrusion 232 may extend (e.g., upwardly and outwardly) from the main body 260. In this manner, the piston seal 222 may define an L-type seal, although other configurations are contemplated. In one example, the first and second sealing protrusions 230, 232 may be separated by a groove 234. The first sealing protrusion 230 may be a rounded bump or bulge protruding from the main body 260. The second sealing protrusion 232 may be a thin wall extending at an angle from the main body 260 to flex inward. Like the piston seal 122, the piston seal 222 may be formed of a flexible and / or elastic element, such as rubber or another elastomer and be able to deform to define a sealed connection between two elements.
[0065] The piston seal 222 may be positioned within the seal groove 224 to seal a space between the piston 220 and the interior surface of the pump body 114. For instance, as best shown in Fig. 8B, the main body 260 may be positioned in the first cavity 246, such as within the annular groove 250. In one example, the first sealing protrusion 230 may be positioned at least partially in the first cavity 246. The second sealing protrusion 232 may be positioned in the second cavity 248. In such examples, the second sealing protrusion 232 may be positioned to flex inward towards the angled wall 252.
[0066] When positioned within the seal groove 224 to seal the piston 220 against the interior surface of the pump body 114, the piston seal 222 may define at least one grease store to facilitate lubrication. For example, as best shown in Fig. 8B, the seal groove 224 may be shaped to define a first grease store 264 between the second sealing protrusion 232 and the angled wall 252. In addition, or alternatively, the groove 234 between the first and second sealing protrusions 230, 232 may define a second grease store 266. The second grease store 266 may be defined between the piston seal 222 and the pump body. Each grease store may be defined as a pocket or cavity between the piston assembly 219 and the pump body to store, hold, or otherwise receive lubricant. For example, the first grease store 264may hold lubricant between the piston seal 222 and the piston 220. The second grease store 266 may hold lubricant between the piston seal 222 and the pump body 114. The lubricant stored or held in the grease stores may lubricate the piston assembly 219 (e.g., the piston seal 222, the piston 220, etc.) during operation, such as via migration of the stored lubricant towards the interface between the piston assembly 219 and the pump body 114.
[0067] Figs. 13-14 show another implementation of a dual seal configuration. In examples, the sealing protrusions 130 and 132 may be embodied on, or as, separate seals spaced apart or separate from each other. For example, the first sealing protrusion 130 may be embodied on a first seal 267, and the second sealing protrusion 132 may be embodied on a second seal 268. The first and second seals 267, 268 may be positioned within respective grooves of the piston 120. The first and second seals 267, 268 may be spaced apart along a length of the piston 120. For example, the first and second seals 267, 268 may be spaced from each other to define a gap 269 between the seals. The gap 269 may be equal to or less than the size of a seal itself. The gap 269 may be equal to or less than the size of the head or flanged portion 126. The first seal 267 may be positioned between the second seal 132 and the head or flanged portion 126 of the piston 120.
[0068] In examples, the separate first and second seals 267, 268 may be ll-cup seals oriented in the same or opposite direction. For example, referring to Fig. 13, the ll-cups of the first and second seals 267, 268 may be arranged or oriented in opposite directions, such as facing away from each other as shown. Referring to Fig. 14, the ll-cups of the first and second seals 267, 268 may be arranged in the same direction, such as both facing the head or flanged portion 126 as shown. Such examples are illustrative only, and the first and second seals 267, 268 may be arranged or oriented differently.
[0069] Figs. 15-16 are various views of another implementation of the piston assembly 219. In embodiments, the piston 220 may include a rod cutout 270 (e.g., defined in a sidewall 272 of the piston 220). The rod cutout 270 may extend from the bottom of the piston 220 towards the head portion 226, such as terminating before the piston seal 222 (not shown for illustration purposes). The rod cutout 270 may enable coupling of the connecting arm 118 to the piston 220, such as allowing lateral insertion of the connecting arm 118 through the sidewall 272 and into the connecting cavity 228. For example, the rod cutout 270 may have a shape corresponding to a portion of the connecting arm 118 and / or enable flexibility of the sidewall 272 for arm insertion / removal. In one embodiment, the rod cutout 270 may have a keyhole-type shape (e.g., a frustum shape terminating with a circular shape).
[0070] In embodiments, the piston 220 may include one or multiple apertures to enable connection of the piston 220 to the connecting arm 118. For instance, the piston 220 may include a first aperture 274 and a second aperture 276, such as defined on opposite sides of the piston 220. One or both of the apertures 274, 276 may extend into or define the rodcutout 270, although other configurations are contemplated (e.g., positioned on different sides from the rod cutout 270, above the rod cutout 270, etc.). In examples, the apertures 274, 276 may define one or more bearings (e.g., a first bearing 278 and a second bearing 280).
[0071] The connecting arm 118 may include a shaft 284 terminating at a shaft end 286. The shaft 284 may have a tapered shape (e.g., tapering towards the shaft end 286). The tapered shape may correspond to the shape of the rod cutout 270, such as to facilitate coupling of the shaft 284 to the piston 220. In examples, the shaft end 286 may define an integrated pin or rod 288 for coupling to the piston 220. For instance, the shaft end 286 or pin 288 may include or define one or more bearing surfaces (e.g., a first bearing surface 292 and a second bearing surface 294). In such examples, the bearing surfaces may engage the bearings of the piston 220, such as the first bearing surface 292 engaging the first bearing 278 and the second bearing surface 294 engaging the second bearing 280. In this manner, the piston 220 may rotate around the shaft end 286, such as to allow relative movement between the piston 220 and the connecting arm 118 during pump operation.
[0072] Fig. 17 illustrates another implementation of piston 220. In embodiments, the head portion 226 may implement a seal. For example, the piston 220 may include an end cap seal 296 at or defining the distal or top end of the piston 220. The end cap seal 296 may be used in place of or in addition to the piston seal 222. For example, the end cap seal 296 may form the piston seal 222, or the end cap seal 296 may form a second piston seal separate from the piston seal 222. In some examples, the end cap seal 296 may be spaced from the piston seal 222, such as spaced along the length of the piston 220. The end cap seal 296 may include one or more annular protrusions, bumps, or bulges extending to seal against the inner surface of the pump cavity 115. In examples, the end cap seal 296 may be coupled to, wrap around or replace the skirt 240.
[0073] Fig. 18 illustrates another implementation of piston assembly 219. In embodiments, the piston seal 222 may be implemented separate from the piston 220. For example, instead of on the piston 220, the piston seal 222 may be implemented on or in the pump body 114. For instance, the seal groove 224 may be defined in the interior surface defining the pump cavity 115 (e.g., the pump body 114 has the piston seal 222). In other words, rather than secured to the piston 220 to move with the piston 220 within the pump cavity 115, the piston seal 222 may be secured to the interior surface / pump cavity 115 to allow movement of the piston 220 relative thereto. In such examples, the protrusions of the piston seal 222 may extend to engage the piston 220.
[0074] The foregoing description has broad application. For example, while examples disclosed herein may focus on a pump for an oral irrigator, it should be appreciated that the concepts disclosed herein may equally apply to other motor driven devices where sealing apiston is desired. Accordingly, the discussion of any example is meant only to be exemplary and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples.
[0075] Although the present invention has been described with reference to preferred examples, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. The invention is limited only by the scope of the following claims.
Claims
CLAIMSWhat is claimed is:
1. An oral irrigator comprising a piston; and a piston seal positioned around the piston, wherein the piston seal comprises a first protrusion and a second protrusion.
2. The oral irrigator of claim 1, further comprising a pump body, wherein the first protrusion and the second protrusion seal against the pump body to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
3. The oral irrigator of claim 1 or 2, wherein a groove is defined between the first protrusion and the second protrusion, the groove defining a grease store to hold lubricant between the piston seal and the pump body.
4. The oral irrigator of any of claims 1-3, wherein the piston seal is configured to define a grease store to hold lubricant between the piston seal and the piston.
5. The oral irrigator of claim 4, wherein the piston comprises a skirt extending from the seal groove.
6. The oral irrigator of any of claims 1 or 3-5, further comprising a pump body, wherein the pump body includes the piston seal.
7. The oral irrigator of any of claims 1-6, further comprising a second piston seal positioned on an end of the piston.
8. An oral irrigator comprising a piston; and a piston seal positioned around the piston, wherein the piston seal is configured to define a grease store to hold lubricant between the piston seal and the piston.
9. The oral irrigator of claim 8, wherein the piston seal comprises a first sealing protrusion and a second sealing protrusion.
10. The oral irrigator of claim 9, wherein the grease store is defined between the second sealing protrusion and the piston.
11. The oral irrigator of any of claims 9-10, further comprising a pump body, wherein the first sealing protrusion and the second sealing protrusion seal against the pump body to limit fluid from leaking around the piston as the piston moves relative to the pump body.
12. The oral irrigator of claim 11 , wherein a groove is defined between the first sealing protrusion and the second sealing protrusion, the groove defining a second grease store to hold lubricant between the piston seal and the pump body.
13. The oral irrigator of claim 9, further comprising a pump body, wherein a groove is defined between the first sealing protrusion and the second sealing protrusion, the groove defining the grease store to hold the lubricant between the piston seal and the pump body.
14. The oral irrigator of any of claims 8-13, further comprising a second piston seal positioned on an end of the piston.
15. An oral irrigator comprising: a piston; a pump body; and a piston seal comprising a main body and a pair of protrusions extending from the main body to seal the piston to the pump body.
16. The oral irrigator of claim 15, wherein the first protrusion and the second protrusion seal against the pump body to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
17. The oral irrigator of claim 15, wherein the first protrusion and the second protrusion seal against the piston to prevent fluid from leaking around the piston as the piston moves relative to the pump body.
18. The oral irrigator of claim 16 or 17, further comprising a groove defined between the first protrusion and the second protrusion, the groove defining a grease store to hold lubricant between the piston seal and the pump body.
19. The oral irrigator of any of claims 15-18, wherein the piston comprises a skirt and a deflection cavity allowing the skirt to flex inwardly.
20. The oral irrigator of any of claims 15-19, further comprising a second piston seal positioned on an end of the piston.21 . An oral irrigator comprising: a pump body; a piston comprising a seal groove; and a piston seal received in the seal groove, the piston seal comprising a pair of protrusions separated by a groove, the pair of protrusions configured to sealingly engage the pump body.
22. An oral irrigator comprising: a piston comprising a seal groove defined around a circumference of the piston; a first seal positioned within the seal groove; and a second seal separate from the first seal and defining a distal end of the piston.
23. An oral irrigator comprising: a piston; a pump body comprising a seal groove; and a piston seal positioned within the seal groove of the pump body and extending to engage the piston.