GB2584005A

GB2584005A - Vacuum pump exhaust reed valve with pressure bleed

Info

Publication number: GB2584005A
Application number: GB2003376.7A
Authority: GB
Inventors: A Dods James; Andrew Leggott Paul; Tooley Simon
Original assignee: Cummins Inc
Current assignee: Cummins Inc
Priority date: 2019-03-22
Filing date: 2020-03-09
Publication date: 2020-11-18
Anticipated expiration: 2040-03-09
Also published as: GB2584005B; CN111720581B; GB202003376D0; CN111720581A

Abstract

A system including a vacuum pump 400 and an exhaust reed valve 402 coupled to the vacuum pump. The exhaust reed valve includes a reed valve seal (fig.3, 302), and a body 402. The reed valve seal includes a groove (fig.3, 308), and/or the body defines a hole 404 that extends entirely through the body. The sealing surface is operable to contact the body and create a seal, and the groove is operable to create an unsealed space from which pressurized fluid can escape. The hole is sized to permit pressurised fluid to escape through the hole when the pump is not operating, but also small enough to prevent pressurised fluid from escaping at a rate to prevent a vacuum from being generated when the vacuum pump is operating. The hole and groove are configured to provide a partial seal such that the pressure of the vacuum pump equalises faster when the pump shuts down. This can eliminate detrimental effects such as hydraulic locking and large loads on the cam drive.

Description

VACUUM PUMP EXHAUST REED VALVE WITH PRESSURE BLEED

CROSS-REFERENCE TO RELATED APPLICATIONS

100011 The present application claims priority to U.S. Provisional Application No. 62/822,330, filed March 22, 2019, the content of which is hereby incorporated by reference in its entirety.

ILCHNICAL FIELD

10002] The present invention relates generally to systems for moderating pressure within a vacuum pump associated with an internal combustion engine system.

BACKGROUND

100031 Internal combustion engine systems may incorporate a vacuum pump. In such systems, vacuum pumps may produce a vacuum of 0.7 -0.9 bar and can be used for braking assistance, operating pneumatic equipment, positioning flaps (e.g., exhaust flaps), operatinu. valves (e.g., EGR valves), switching the intake manifold, turbocharger control, etc. A vacuum pump may be a traditional type of pump that moves a piston back and forth; however, a vacuum pump may also be a vane pump with a rotary drive. A single vane vacuum pump can be installed directly to a cylinder head and driven by the camshaft. Vacuum pumps require oil for lubrication, heat dissipation, and internal sealing. Typically, oil is supplied through ducts in the cylinder head or the camshaft and is fed back to the engine along with exhaust air.

100041 In some vacuum pumps, a reed valve is included to reduce the pump work load once the desired vacuum level is reached. The reed valve also maintains vacuum pressure in the pump when the engine is shut down. In some cases, the vacuum pressure in the pump maintained by the reed valve can draw additional oil into the pump and potentially cause hydraulic locking. Furthermore, when the engine is started while the vacuum pump is filled with oil, a large load can be exerted on the cam drive system, causing overload conditions and potential failures. -1 -

Accordingly, including a full reed valve to maintain vacuum pressure is undesirable. Removing the reed valve entirely can allow the vacuum pump to equalize in pressure with the crankcase and limit the volume of oil drawn into the pump. However, the absence of a reed valve can cause additional crankcase pressure pulsations and consequently higher peak breather flow pulsation. Accordingly, removing the reed valve entirely is also undesirable.

SUMMARY

10005] In one embodiment, a system includes a vacuum pump and an exhaust reed valve coupled to the vacuum pump. The exhaust reed valve includes a reed valve seal, a connection portion rigidly coupled to the vacuum pump, and a stem portion rigidly coupled to the connection portion and a body. The reed valve seal defines a sealing surface and a groove, the groove being recessed below the sealing surface. The sealing surface is operable to contact the body and create a seal, and the groove is operable to create an unsealed space from which pressurized liquid and/or vapor can escape between the body and the reed valve seal.

100061 In another embodiment, a system includes a vacuum pump and an exhaust reed valve coupled to the vacuum pump. The exhaust reed valve includes a reed valve seal, a connection portion rigidly coupled to the vacuum pump, and a stem portion rigidly coupled to the connection portion and a body, the body defining a hole extending entirely through the body. The reed valve seal defines a sealing surface, the sealing surface operable to contact the body and create a seal. The hole is sized to permit pressurized liquid and/or vapor to escape through the hole when the vacuum pump is not operating. The hole is also sized to prevent pressurized liquid and/or vapor from escaping through the hole at a rate to prevent a vacuum from being generated when the vacuum pump is operating.

100071 In another embodiment, a system includes a vacuum pump and an exhaust reed valve coupled to the vacuum pump. The exhaust reed valve includes a connection portion rigidly coupled to the vacuum pump, a stem portion rigidly coupled to the connection portion, and a body defining a hole extending entirely through the body. A reed valve seal defines a sealing surface and a groove recessed below the sealing surface. The sealing surface is operable to -2 -contact the body and create a seal, and the groove is operable to create an unsealed space between the body and the sealing surface, thereby allowing pressurized liquid and/or vapor to escape between the body and the reed valve seal. The hole is sized to permit pressurized liquid and/or vapor to escape through the hole when the vacuum pump is not operating, and the hole is sized to prevent pressurized liquid and/or vapor from escaping through the hole at a rate to prevent a vacuum from being generated when the vacuum pump is operating.

BRIEF DESCRIPTION OF THE DRAWINGS

100081 The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the disclosure will become apparent from the description, the drawings, and the claims, in which: 100091 FIG. 1 is a front perspective view of a conventional vane vacuum pump.

100101 FIG. 2 is a back perspective view of the conventional vane vacuum pump of FIG. 1. 100111 FIG. 3 is an illustration of a reed valve seal, according to a particular embodiment.

100121 FIG. 4 is an illustration of a vane vacuum pump including an exhaust reed valve with a bleed hole, according to a particular embodiment.

DETAILED DESCRIPTION

100131 Following below are more detailed descriptions of various concepts related to, and implementations of, methods, apparatuses, and systems for bleeding pressure through an exhaust reed valve of a vacuum pump of an internal combustion engine system. The various concepts introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

1. Overview 100141 A vacuum pump system associated with an internal combustion engine may include an exhaust reed valve. The exhaust reed valve functions to reduce the work load of the vacuum pump once the desired vacuum level is reached. The exhaust reed valve also maintains vacuum pressure in the pump when the engine is shut down. However, the vacuum pressure in the pump maintained by the exhaust reed valve can draw additional oil into the pump and potentially cause hydraulic locking. Furthermore, when the engine is started while the vacuum pump is filled with oil, a large load can be exerted on the cam drive system, causing overload conditions and potential failures. Sonic vacuum pump systems eliminate the exhaust reed entirely, resulting in breather flow pulsation.

100151 Implementations herein relate to modifications of an exhaust reed valve for a vacuum pump. One modification may include creating a hole through the exhaust reed valve. Another modification may include creating a cutout in the exhaust reed valve sealing surface. Both modifications result in a partial seal between the exhaust reed valve and the vacuum pump. The partial seal allows the pressure of the vacuum pump to equalize faster when the engine shuts down, as compared to when a full seal exists between the exhaust reed valve and the vacuum pump. The partial seal also functions to allow sufficient crank case gas to refill the vacuum pump before too much oil is drawn into the pump upon engine shutdown. As a result, implementations herein provide for the desirable effects of including an exhaust reed valve (e.g., providing pressure stabilization while allowing sufficient crank case gas to equalize in the pump) while eliminating the detrimental effects of including such a valve (e.g., hydraulic locking and large loads on the cam drive at startup).

Example Exhaust Reed Valve System 100161 FIG. 1 is a front perspective view of a conventional vane vacuum pump 100. The vane vacuum pump 100 is rigidly coupled to an internal combustion engine such that the vane vacuum pump 100 creates sufficient vacuum within the internal combustion engine. The vane vacuum pump 100 includes a chamber 102, a rotor 104, a vane 106, an inlet 108, a chamber sealing -4 -surface 110, and an exhaust outlet (not shown) that is obscured by the rotor 104. The vane vacuum pump 100 is shown without a cover for purposes of illustration. In operation, the vane vacuum pump 100 includes a cover coupled to the chamber sealing surface 110 to seal the chamber 102.

100171 The rotor 104 is rotatably coupled to the chamber 102 and rigidly coupled to the vane 106. The rotor 104 functions to rotate within the chamber I 02 such that the vane 106 rotates within the chamber 102. The rotor 104 is also rigidly coupled to the camshaft of the internal combustion engine such that, as the camshaft rotates, the rotor 104 also rotates.

100181 The vane 106 is rigidly coupled to the rotor 104 such that the vane 106 rotates as the rotor 104 rotates. The vane 106 functions to create a seal against the chamber 102 such that liquid and/or vapor cannot escape the sealed area as the vane 106 rotates. In some embodiments, the vane 106 creates two seals against the chamber 102, where the two seals are diametrically opposite each other. In other embodiments, the vane 106 creates more than two seals against the chamber 102, each seal spaced substantially equidistant from the other seals. In sonic implementations, the vane 106 includes additional sealing surfaces that function to create a seal against the chamber 102. In other implementations, the vane 106 creates the seal against the chamber 102 without the additional sealing surfaces.

100191 The inlet 108 is defined by an opening within the chamber 102. The inlet 108 functions to allow liquid and/or vapor (e.g., gas and/or oil) from the internal combustion engine to enter the chamber 102. As the vane 106 rotates within the chamber 102, the liquid and/or vapor occupies the space in between the sealed surfaces of the vane 106. As the vane 106 continues to rotate, the trapped liquid and/or vapor rotates in between the sealed surfaces. When one of the sealed surfaces passes the outlet, the liquid and/or vapor exits the vacuum pump 100 through the exhaust outlet, thereby creating the vacuum.

100201 FIG. 2 is a back perspective view of the conventional vane vacuum pump 100 of FIG. 1. The vane vacuum pump 100 is further shown to include an exhaust reed valve 124, a reed valve sealing surface 126, and a reed valve connector 128. -5 -

100211 The exhaust reed valve 124 functions to cover the outlet to maintain vacuum pressure in the vane vacuum pump 100 during operation and reduce parasitic losses when the vacuum is generated. The vane vacuum pump 100 operates when an internal combustion engine system that requires the vane vacuum pump 100 (e.g., a braking assistance system) is also operating. When the system that requires the vane vacuum pump 100 stops operating, the exhaust reed valve 124 allows the vane vacuum pump 100 to stop operating by maintaining the pressure in the vane vacuum pump 100. Thus, the parasitic loss associated with the vane vacuum pump 100 being in constant operation is reduced. In addition, by maintaining the vacuum pressure in the vane vacuum pump 100, the exhaust reed valve 124 prevents pumping losses.

10022] In some implementations, the exhaust reed valve 124 is constructed as a singular component. In other implementations, the exhaust reed valve 124 is constructed as a combination of multiple components. The exhaust reed valve 124 is preferably constructed from a substantially elastic material such that the exhaust reed valve 124 can undergo elastic deformation and return to its original shape. In sonic embodiments, the exhaust reed valve 124 is constructed from a metal (e.g., stainless steel, aluminum, etc.). In other embodiments, the exhaust reed valve 124 is constructed from a plastic or composite suitable for the high temperatures encountered in an internal combustion engine.

100231 The exhaust reed valve 124 further includes a connection portion 130, a stem 132, and a body 134. The connection portion 130 is rigidly connected to the vane vacuum pump 100 via the reed valve connector 128. The reed valve connector 128 is rigidly coupled to both the connection portion 130 and the vane vacuum pump 100 such that the connection portion 130 cannot move relative to the vane vacuum pump 100. The stem 132 functions to rigidly connect the connection portion 130 to the body 134. In general, the width of the stem 132 is smaller than the width of both the connection portion 130 and the body 134. As such, the stem 132 is generally more flexible than the body 134.

100241 The body 134 is rigidly coupled to the stem 132 and functions to cover the reed valve sealing surface 126 such that a seal is created between the body 134 and the sealing surface 126. -6 -

In some embodiments, the body 134 comprises a racetrack shape (e.g., a rectangle with semicircles positioned at opposite ends of the rectangle). The body 134 can also comprise various other shapes (e.g., oval, circular, etc.). When the liquid and/or vapor within the chamber 102 reaches a sufficient pressure and reaches the outlet, the liquid and/or vapor pushes against the body 134. When the liquid and/or vapor pushes against the body 134, the force of the liquid and/or vapor is transmitted to the stem 132 such that the stem 132 undergoes elastic deformation and the seal between the body 134 and the sealing surface 126 is broken, thus allowing the liquid and/or vapor to leave the chamber 102 via the outlet.

10025] As described previously, in many conventional systems, the exhaust reed valve 124 maintains vacuum pressure in the vane vacuum pump 100 when the engine is shut down. The pressure remains in the vane vacuum pump 100 and cannot dissipate and, as a result, oil from the lubrication system of the internal combustion engine is drawn into the vane vacuum pump 100, which can cause hydraulic locking.

10026] FIG. 3 is an illustration of a reed valve seal 300, according to a particular embodiment. The reed valve seal 300 includes a sealing surface 302, an outer wall 304, an inner wall 306, and a groove 308. The reed valve seal 300 functions to provide a mating surface for the exhaust reed valve 124 to create a seal.

10027] The sealing surface 302 is defined by the outer wall 304 and the inner wall 306, and is substantially the same shape as the body 134 (e.g., a racetrack shape, etc.), with the perimeter of the outer wall 304 being substantially (e.g., within ten percent) the same as the perimeter of the body 134. In some embodiments, a width of the sealing surface 302 (e.g., a perpendicular distance between the outer wall 304 and the inner wall 306) is substantially constant. The width of the sealing surface 302 can also be non-constant such that the sealing surface is wider in some locations and narrower in other locations. The inner wall 306 defines the outlet through which the liquid and/or vapor flows. In some embodiments, the shape of the outlet is substantially similar to the shape of the body 134 (e.g., racetrack shape, etc.). The shape of the outlet can also comprise other shapes (e.g., oval, circular, etc.) -7 - 100281 The groove 308 is defined by a slot within the sealing surface 302, extending from the outer wall 304 through the inner wall 306. In some implementations the groove 308 is recessed approximately 0.1 mm below the sealing surface 302 and is approximately 2 mm long. In other implementations, the dimensions of the groove 308 may change depending on the type of internal combustion engine or the desired pressure level in the vane vacuum pump 100. The groove 308 may be located in any position along the sealing surface 302. In some embodiments, multiple grooves 308 may be distributed around the sealing surface 302 to provide the desired results. In embodiments where multiple grooves 308 are implemented, the grooves 308 may differ in size and shape to produce the desired results.

10029] The groove 308 provides a space over which the exhaust reed valve 124 does not create a seal with the sealing surface 302. Accordingly, when the exhaust reed valve 124 mates with the sealing surface 302, some pressure within the vane vacuum pump 100 is released through the space between the exhaust reed valve 124 and the groove 308, thereby allowing the pressure of the vacuum pump to bleed out when the engine shuts down and allowing sufficient crank case gas to refill the vacuum pump before too much oil is drawn into the pump upon engine shutdown, so as to help prevent hydraulic locking and a large load on the chain. The pressure equalization time is related to the size of the groove 308. For example, a smaller groove 308 will take a longer time to equalize pressure than a larger groove 308.

100301 FIG. 4 is an illustration of a vane vacuum pump 400 including an exhaust reed valve 402 with a bleed hole 404, according to a particular embodiment. The vane vacuum pump 400 is substantially identical to the vane vacuum pump 100 of FIG. 1, except for the inclusion of the bleed hole 404 in the exhaust reed valve 402. In some implementations, the bleed hole 404 is defined by a cylindrical cut extending entirely through the exhaust reed valve 402. In other implementations, the shape of the bleed hole 404 can be other than cylindrical (e.g., square, rectangular, etc.) In some embodiments, the bleed hole 404 is a constant cross-sectional shape. In other embodiments, the cross-sectional shape of the bleed hole 404 changes (e.g., changes in shape, size, etc.). In some arrangements, the bleed hole 404 is a circular shape with a diameter of approximately 0.5mm. In other arrangements, the bleed hole 404 may be larger or smaller to -8 -produce the desired results. The pressure equalization time is related to the size of the bleed hole 404. For example, a smaller bleed hole 404 will take a longer time to equalize pressure than a larger bleed hole 404.

100311 The bleed hole 404 can be located anywhere on the exhaust reed valve 402 such that the bleed hole 404 is in fluid communication with the vane vacuum pump 100. In some implementations, a single bleed hole 404 is used In other embodiments, multiple bleed holes 404 can be used to produce the desired results.

III. Example Operation of Exhaust Reed Valve Systems 100321 With reference to FIGS. 1 -2, an internal combustion engine includes a vane vacuum pump 100. The vane vacuum pump 100 functions to maintain a vacuum in the internal combustion engine as the rotor 104 turns the vane 106 within the chamber 102. To avoid the potential detrimental effects of using an exhaust reed valve 124 without any modifications (e.g., pressure retention in the vacuum pump leading to oil retention and potential failures), the exhaust reed valve system is modified to prevent such detrimental effects.

[00331 With reference to FIGS. 1 -4, the detrimental effects can be eliminated by modifying the sealing surface 126 to create the reed valve seal 300 that mates with the exhaust reed valve 124. During normal engine operation, the vane vacuum pump 100 operates normally, with the vane 106 rotating and creating a vacuum for the internal combustion engine. The rotation of the vane 106 causes the liquid and/or vapor within the chamber 102 to be expelled through the outlet. When the liquid and/or vapor are expelled, the exhaust reed valve 124 is deflected to break the seal between the exhaust reed valve 124, allowing the liquid and/or vapor to escape.

[00341 When the internal combustion engine is shut down, the vane vacuum pump 100 also shuts down such that the chamber 102 remains pressurized. However, the groove 308 provides a non-sealed space between the exhaust reed valve 124 and the sealing surface 302 through which the liquid and/or vapor can slowly escape, thereby slowly bleeding the pressure from the vane vacuum pump 100 to significantly reduce the pressure within the chamber 102. In addition, by -9 -slowly bleeding the pressure from the vane vacuum pump 100, the amount of oil carryover is significantly reduced as compared to a pump with no exhaust reed valve 124.

100351 With reference to FIGS. 1, 2, and 4, the detrimental effects can also be eliminated by modifying the exhaust reed valve 124 to create the exhaust reed valve 402. After the internal combustion engine is turned off, the chamber 102 remains pressurized, as previously described. However, the hole 404 provides a non-sealed space extending through the exhaust reed valve 402 through which the liquid and/or vapor can slowly escape, thereby slowly bleeding the pressure from the vane vacuum pump 100 to significantly reduce the pressure within the chamber 102. In addition, by slowly bleeding the pressure from the vane vacuum pump 100, the amount of oil carryover is significantly reduced as compared to a pump with no exhaust reed valve 402.

IV. Construction of Example Embodiments 100361 While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed but rather as descriptions of features specific to particular implementations. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

100371 As utilized herein, the terms -approximately," "substantially" and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of -10-these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims [00381 The terms "coupled," "connected," and the like, as used herein, mean the joining of two components directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two components or the two components and any additional intermediate components being integrally formed as a single unitary body with one another, with the two components, or with the two components and any additional intermediate components being attached to one another.

10039] It is important to note that the construction and arrangement of the system shown in the various example implementations is illustrative only and not restrictive in character. All changes and modifications that come within the spirit and/or scope of the described implementations are desired to be protected. It should be understood that some features may not be necessary, and implementations lacking the various features may be contemplated as within the scope of the application, the scope being defined by the claims that follow. When the language a "portion" is used, the item can include a portion and/or the entire item unless specifically stated to the contrary.

100401 Also, the term or is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Conjunctive language such as the phrase "at least one of X, Y, and unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated.

100411 Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple components or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any method processes may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

-12 -

Claims

WHAT IS CLAIMED IS: A system, comprising: a vacuum pump; an exhaust reed valve coupled to the vacuum pump, the exhaust reed valve comprising: a connection portion rigidly coupled to the vacuum pump, and a stem portion rigidly coupled to the connection portion and a body and a reed valve seal defining a sealing surface and a groove, the groove being recessed below the sealing surface; wherein the sealing surface is operable to contact the body and create a seal, and the groove is operable to create an unsealed space between the body and the sealing surface, thereby allowing pressurized liquid and/or vapor to escape between the body and the reed valve seal.
2. The system of claim 1, further comprising: an outer wall defining an outer boundary of the reed valve seal; and an inner wall defining an inner boundary of the reed valve seal; wherein the groove extends through the reed valve seal through the outer wall and the inner wall.
3. The system of claim 2, wherein the groove maintains the same cross-sectional shape from the inner wall to the outer wall.
4. The system of claim 2, wherein a cross-sectional shape of the groove changes from the inner wall to the outer wall.
5. The system of any of claims 2 to 4, wherein a perimeter of the outer wall is substantially the same as a perimeter of the body.
6. The system of any preceding claim, wherein a shape of the sealing surface is substantially the same as a shape of the body.
-13 - 7 The system of any preceding claim, wherein the groove comprises multiple grooves distributed around the sealing surface.
8. A system, comprising; a vacuum pump; an exhaust reed valve coupled to the vacuum pump, the exhaust reed valve comprising: a connection portion rigidly coupled to the vacuum pump, and a stem portion rigidly coupled to the connection portion and a body, the body defining a hole extending entirely through the body; and a reed valve seal defining a sealing surface, the sealing surface operable to contact the body and create a seal; wherein the hole is sized to permit pressurized liquid and/or vapor to escape through the hole when the vacuum pump is not operating, and the hole is sized to prevent pressurized liquid and/or vapor from escaping through the hole at a rate to prevent a vacuum from being generated when the vacuum pump is operating.
9. The system of claim 8, wherein the hole is approximately 0.3mm to 1.0mm in diameter.
10. The system of claim 8, wherein the hole is approximately 0.1mm to 1.5mm in diameter.
11. The system of any of claims 8 to 10, wherein the hole comprises a cylindrical cut extending entirely through the body.
12. The system of claim 11, wherein the cylindrical cut comprises a constant cross-sectional shape.
13. The system of claim 8, wherein the hole comprises a non-constant cross-sectional shape.
-14 - 14. The system of any of claims 8 to 13, wherein the hole comprises multiple bleed holes located on the exhaust reed valve.
15. A system, comprising: a vacuum pump; an exhaust reed valve coupled to the vacuum pump, the exhaust reed valve comprising: a body defining a hole extending entirely through the body; a connection portion rigidly coupled to the vacuum pump, and a stem portion rigidly coupled to the connection portion and the body; and a reed valve seal defining a sealing surface and a groove, the groove being recessed below the sealing surface; wherein the sealing surface is operable to contact the body and create a seal, and the groove is operable to create an unsealed space between the body and the sealing surface, thereby allowing pressurized liquid and/or vapor to escape between the body and the reed valve seal, and wherein the hole is sized to permit pressurized liquid and/or vapor to escape through the hole when the vacuum pump is not operating, and the hole is sized to prevent pressurized liquid and/or vapor from escaping through the hole at a rate to prevent a vacuum from being generated when the vacuum pump is operating.
16. The system of claim 15, further comprising: an outer wall defining an outer boundary of the reed valve seal; and an inner wall defining an inner boundary of the reed valve seal; wherein the groove extends through the reed valve seal through the outer wall and the inner wall.
17. The system of claim 16, wherein the groove maintains the same cross-sectional shape from the inner wall to the outer wall.
18. The system of claim 16, wherein a cross-sectional shape of the groove changes from the inner wall to the outer wall.
-15 - 19. The system of any of claims 15 to 18, wherein the hole comprises a cylindrical cut extending entirely through the body.
20. The system of claim 19, the cylindrical cut comprising a constant cross-sectional shape. -16-