Patent Description:
Numerous tasks, for example, cutting sheet metal or abrading a surface, may be accomplished through the use of a stream of pressurized fluid, typically water, which is generated by high pressure or ultrahigh pressure, positive displacement pumps, including, for example, those capable of generating pressurized fluid up to and beyond <NUM> × <NUM><NUM> Pa (<NUM>,<NUM> psi) and including over <NUM> × <NUM><NUM> Pa (<NUM>,<NUM> psi). Such pumps pressurize a fluid by having a reciprocating plunger that draws the fluid from an inlet area into a pressurization chamber during an intake stroke, and acts against the fluid during a pumping stroke, thereby forcing pressurized fluid to pass from the pressurization chamber to an outlet chamber where it is collected to be used by an operator via whatever tool has been attached to the pump for a particular task.

During the normal course of operation, the required flow rate will vary from the maximum the pump can supply to zero, for example, when the operator turns the tool off. In this situation, where the pressurized fluid is not being used, the pressure in the outlet chamber will build up beyond an acceptable level unless some form of pressure control is incorporated into the pump. If no pressure regulation is provided, the buildup of pressure will result in damage and stress to the parts of the pump and undesirable surges of pressure will occur when the operator again turns the tool on.

One method of pressure control that is currently used is to incorporate a regulator valve (also sometimes referred to as a relief valve) into the pump system. When the pressure in the outlet chamber rises above a preset limit as a result of pressurizing more water than is demanded, the regulator valve opens to vent or relieve the pressurized fluid. A regulator valve may be direct acting, meaning that pressurized fluid acts directly to open a poppet that is being held in a closed position by a control force, such as, for example a spring or other biasing mechanism. Example regulator or relief valves are shown and described in <CIT>, , and which is assigned to the assignee of the present application, Flow International Corporation of Kent, Washington. While currently available direct acting regulator valves for use in connection with high pressure and ultrahigh pressure pumps provide suitable pressure regulation under many operating conditions, in some instances, a pressure signal corresponding to the system pressure can oscillate unsatisfactorily above and below a desired pressure due to variations in the hydrostatic and hydrodynamic forces acting on the regulator valve during operation. Applicants believe improved regulator valves less susceptible to pressure oscillations are desirable. <CIT> describes a solenoid valve which is capable of effectively dampening an allophone by a relatively simple construction. <CIT> discloses a prior art valve pin.

Accordingly there is provided a valve pin as detailed in the claims that follow.

In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one of ordinary skill in the relevant art will recognize that embodiments may be practiced without one or more of these specific details. In other instances, well-known structures associated with high pressure and ultrahigh pressure fluid systems, including high pressure and ultrahigh pressure pumps, regulator or relief valves and components thereof, may not be shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments.

Unless the context requires otherwise, throughout the specification and claims which follow, the word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be construed in an open, inclusive sense, that is as "including, but not limited to.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

<FIG> show a regulator valve assembly <NUM> according to one example embodiment. The regulator valve assembly <NUM> is operable with a high pressure or ultrahigh pressure pump (not shown) or other fluid system to provide pressure regulating functionality with respect to operating pressures up to and beyond <NUM><NUM> Pa (<NUM>,<NUM> psi) and including over <NUM> X <NUM><NUM> Pa (<NUM>,<NUM> psi). During operation, the pump pressurizes fluid, typically water, to pressures up to and beyond <NUM><NUM> Pa <NUM>,<NUM> psi, the pressurized fluid being collected and used by an operator via a tool (not shown) selected for a particular task, such as, for example, fluid jet cutting via a fluid jet nozzle (e.g., waterjet or abrasive waterjet cutting nozzle). During the normal course of operation, the regulator valve assembly <NUM> is used to relieve or bleed fluid to prevent over-pressurization which could otherwise result in damage and stress to parts of the pump and undesirable surges when the tool is reactivated.

As shown in <FIG>, the regulator valve assembly <NUM> is provided with a female valve seat <NUM> which is configured to be in fluid communication with a source of pressurized fluid (e.g., a high pressure or ultrahigh pressure pump) via inlet conduit <NUM> and inlet port <NUM>, as represented by the arrow labeled <NUM>. A male poppet or valve pin <NUM> is provided to mate with the valve seat <NUM>, the valve pin <NUM> being urged into contact with the valve seat <NUM> by a control force that is generated by a pneumatic actuator <NUM> acting on the valve pin <NUM> via a plunger <NUM> or other suitable biasing arrangement.

As shown in <FIG>, a significant portion of the valve pin <NUM> is positioned within the valve seat <NUM> to sealingly engage the valve seat <NUM> in a seated configuration S. When the pressure of the fluid increases sufficiently to overcome the control force, the valve pin <NUM> is forced to move in the direction of the fluid flow to create clearance between the valve pin <NUM> and the valve seat <NUM>, thereby allowing a volume of pressurized fluid to pass through the valve seat <NUM> to an outlet chamber <NUM> of a housing <NUM> enclosing the interface of the valve seat <NUM> and valve pin <NUM> and ultimately through an outlet passage <NUM> of an outlet adapter <NUM> coupled to a housing component <NUM> that is sealingly engaged with the housing <NUM>, as represented by the arrow labeled <NUM>.

<FIG> illustrate further details of the valve seat <NUM> and the valve pin <NUM>. As shown, the valve pin <NUM> includes an elongated engagement portion <NUM> with a tapered surface <NUM>. The valve seat <NUM> has a valve pin receiving aperture <NUM> (i.e., the space that is occupied by the engagement portion <NUM> of the valve pin <NUM> in <FIG>) which defines a tapered surface <NUM> on the valve seat <NUM> to sealingly mate with the engagement portion <NUM> of the valve pin <NUM> when the valve pin <NUM> is seated against the valve seat <NUM> in the seated configuration S (<FIG>). The valve pin <NUM> and/or the valve seat <NUM> may further comprise an asymmetrical surface feature (e.g., notch <NUM> in one side of valve pin <NUM>) that is positioned, sized and shaped such that, when the valve pin <NUM> is displaced away from the seated configuration S to an open configuration O (<FIG>) and fluid flows through an annular space <NUM> created between the engagement portion <NUM> of the valve pin <NUM> and the valve seat <NUM>, unbalanced hydrodynamic forces arise from an interaction of the fluid with the asymmetrical surface feature (e.g., notch <NUM>) to bias an end <NUM> of the valve pin <NUM> away from a central axis Aseat of the valve seat <NUM>.

It will be understood that the valve pin <NUM> may be displaced axially (i.e., in a direction along the central axis Aseat of the valve seat <NUM>) to varying degrees based on changes in system pressure to create the space <NUM> through which pressurized fluid can escape, thereby forming a variable orifice mechanism. Accordingly, the space <NUM> may also be referred to as a variable orifice.

By providing an asymmetrical surface feature (e.g., notch <NUM> at the end <NUM> of the valve pin <NUM>) to asymmetrically disrupt the flow of fluid through the variable orifice <NUM> of the regulator valve assembly <NUM>, a pressure signal corresponding to the system pressure may be substantially stabilized relative to a similar configuration lacking such an asymmetric surface feature by significantly changing the dynamics of the system and biasing the valve pin <NUM> away from a central axis Aseat of the valve seat <NUM>. In other words, the asymmetrical surface feature may substantially minimize fluctuations in the pressure signal by biasing an end <NUM> of the valve pin <NUM> away from the central axis Aseat of the valve seat <NUM> as the fluid passes through the variable orifice <NUM> during operation and interacts with the asymmetrical surface feature to generate unbalanced hydrodynamic forces around the valve pin <NUM>.

As discussed earlier, a housing <NUM> (<FIG>) may enclose the interface of the valve seat <NUM> and valve pin <NUM> and define an outlet chamber <NUM>. The valve seat <NUM> may be positioned within the housing <NUM> such that, when the valve pin <NUM> is displaced away from the seated configuration S, the annular space <NUM> created between the engagement portion <NUM> of the valve pin <NUM> and the valve seat <NUM> is in fluid communication with the fluid outlet chamber <NUM> and an end <NUM> of the valve pin <NUM> is biased away from a centerline or central axis Aseat of the valve seat <NUM> toward a sidewall of the housing <NUM> within the confines of the valve pin receiving aperture <NUM>.

With reference to <FIG>, the asymmetrical surface feature (e.g., notch <NUM>) may be formed in the valve pin <NUM> and may be at most symmetric about only one plane of symmetry that includes the central axis Apin of the valve pin <NUM>. For example, according to the example embodiment of the valve pin <NUM> shown in <FIG>, the notch <NUM> is formed in one side of the end <NUM> of the engagement portion <NUM> and is symmetric only about a single plane of symmetry that includes the central axis Apin, namely, a plane perpendicular to the reference plane P labeled in <FIG>, which bisects the valve pin <NUM> into opposing sides. The asymmetrical surface feature may be described as an indentation, depression, notch, hole, aperture or cavity provided at one of the opposing sides of the valve pin <NUM>. The asymmetrical surface feature of the example embodiment of the valve pin <NUM> shown in <FIG>, for example, is a V-shaped notch with a throat portion thereof located near the reference plane P that bisects the valve pin <NUM>. In some instances, the asymmetrical surface feature (e.g., notch <NUM>) may be located entirely to one side of the vertical reference plane P that includes the central axis Apin of the valve pin <NUM>. In some instances, the asymmetrical surface feature may be bound by a reference prism, namely a semi-cylinder reference prism, defined by the vertical reference plane P and a semicircular outer edge of the valve pin <NUM> at the downstream end of the asymmetrical surface feature projected along a height of the asymmetrical surface feature. In some instances, the asymmetrical surface feature may be offset from a terminal end <NUM> of the valve pin <NUM>, such as, for example, as shown in the example embodiment of <FIG>. In other instances, the asymmetrical surface feature may extend to the terminal end <NUM> of the valve pin <NUM>.

In some embodiments, the tapered surface <NUM> of the valve seat <NUM> defined by the valve pin receiving aperture <NUM> may have a draft angle between about two and about five degrees. In other embodiments, the draft angle may be less than two degrees or greater than five degrees. In a similar fashion, the tapered surface <NUM> of the engagement portion <NUM> of the valve pin <NUM> may have a draft angle between about two and about five degrees, or may have a draft angle less than two degrees or greater than five degrees. Irrespective of the particular draft angles, the tapered surface <NUM> of the valve seat <NUM> defined by the valve pin receiving aperture <NUM> is nevertheless sized to sealingly receive the engagement portion <NUM> of the valve pin <NUM> in the seated configuration S.

In some embodiments, the valve pin <NUM> may be inserted in the valve seat <NUM> to a substantial degree when in the seated configuration S, such as, for example, at least about <NUM> inches. It is believed that by dissipating the energy of the pressurized fluid over a relatively large surface area created by the tapered surface <NUM> of the valve pin <NUM> and the tapered surface <NUM> of the valve seat <NUM>, the energy may be dissipated relatively more slowly, thereby minimizing the destructive effects of erosion and cavitation caused by rapid pressure changes.

To further enhance the performance of the regulator valve assembly <NUM>, annular grooves <NUM> may also be provided on the valve pin <NUM>. In some embodiments, at least one annular groove <NUM> may be positioned near the asymmetric surface feature of the valve pin <NUM>, when provided. A small change in the bypass flow rate across a valve pin <NUM> having annular grooves <NUM> can advantageously result in a significantly smaller pressure change as compared to a similar valve pin <NUM> without such grooves <NUM>. It is believed that by providing annular grooves <NUM> on the valve pin <NUM>, the fluid flow is better maintained in a turbulent condition. In some embodiments, the valve pin <NUM> may also be provided with a wear-resistant coating, such as, for example, titanium nitride.

As illustrated in <FIG>, an exterior surface <NUM> of the valve seat <NUM> proximate to the valve pin receiving aperture <NUM> may be tapered in an opposite direction to that of valve pin receiving aperture <NUM>, such that a ratio of the outer diameter of the valve seat <NUM> to a diameter of valve pin receiving aperture <NUM> is greater in an upstream direction of fluid flow.

Although dimensions of the components described herein may vary depending on operating conditions and other factors, in one example embodiment, the valve seat <NUM> has a valve pin receiving aperture <NUM> that is about <NUM> meter (<NUM> inch) long, having an inner diameter at its smallest end of about <NUM> meter (<NUM> inch) and a draft angle of about <NUM> degrees; the engagement portion <NUM> of the valve pin <NUM> is about <NUM> meter (<NUM> inch) long, having a diameter of <NUM> meter (<NUM> inch) at its smallest end and a draft angle of about <NUM> degrees; and the asymmetric surface feature <NUM> is provided in the form of a notch having a radius of curvature at a throat thereof of about <NUM> × <NUM>-<NUM> meter (<NUM> inch) with a center of the radius of curvature located at about <NUM> × <NUM>-<NUM> meter (<NUM> inch) from the terminal end <NUM> of the valve pin <NUM>, and the notch <NUM> further having opposing notch faces with an included angle therebetween of about <NUM>° to about <NUM>°. In other embodiments, a regulator valve assembly <NUM> may have a valve seat <NUM> and a valve pin <NUM> with features that are scaled to handle a larger or smaller flow rate than the embodiment described immediately above.

With reference to <FIG>, and according to one specific example embodiment, the asymmetric surface feature <NUM> is provided in the form of a V-shaped notch on the valve pin <NUM>. The V-shaped notch has a mouth opening distance A of about <NUM> meter (<NUM> inch) and a downstream end of the mouth opening is located a distance B of about <NUM> meter (<NUM> inch) from the terminal end <NUM> of the valve pin <NUM>. The terminal end <NUM> of the valve pin <NUM> has a width E of about <NUM> meter (<NUM> inch) and a depth of the V-shaped notch is less than or equal to half of the width E of the terminal end <NUM> of the valve pin <NUM>. The V-shaped notch includes opposing notch faces with an included angle α therebetween of about <NUM>°. The valve pin <NUM> further includes annular grooves <NUM> downstream of the V-shaped notch centered at distances C,D of about <NUM> meter (<NUM> inch) and <NUM> meter (<NUM> inch). The cross-sectional profile of the annular grooves <NUM> is a small fraction (e.g., <NUM>/<NUM> or smaller) of the cross-sectional profile of the V-shaped notch.

Comparative tests were conducted between regulator valve assemblies <NUM> each having a valve pin <NUM> with an asymmetric surface feature <NUM> in the form of the aforementioned V-shaped notch described immediately above and similarly constructed regulator valve assemblies lacking such an asymmetric surface feature. The tests were conducted in connection with a host waterjet cutting system at an operating pressure of <NUM> X <NUM><NUM> Pa (<NUM>,<NUM> psi) and under consistent operating parameters. The regulator valve assemblies <NUM> each having the valve pin <NUM> with the asymmetric surface feature <NUM> showed extraordinary improvements in valve performance, namely, in the reduction or elimination of undesirable pressure fluctuations or "bouncing" otherwise observed in instances with valve pins lacking such an asymmetric surface feature <NUM>. For example, no appreciable pressure signal bounce was observed during quick pressure changes such as during on/off valve cycling or during rapid changes in air pressure supplied to a pneumatic actuator <NUM> of the valve assembly <NUM>. Some minimal pressure signal bounce was observed during system startup but quickly dissipated (e.g., within <NUM>-<NUM> in some instances). Regulator valve assemblies <NUM> each having a valve pin <NUM> with an asymmetric surface feature <NUM> in the form of the aforementioned V-shaped notch were also cycle tested for extended operational periods (greater than <NUM> hours) to test durability, and no appreciable wear was detected in the valve pins <NUM> in the vicinity of the asymmetric surface feature <NUM>. Accordingly, the example embodiment exhibited exceptional valve performance and durability.

<FIG> illustrate example embodiments of poppets or valve pins having a variety of asymmetric surface features at an engagement end thereof. It will be appreciated by one of ordinary skill in the relevant art that such asymmetric surface features may be provided in a variety of shapes and sizes and may be tailored to provide suitable dampening, minimization or substantial elimination of pressure fluctuations under various operating conditions and parameters, and may vary in shape, size and location from the example asymmetric surface features of the illustrated embodiments of the valve pins shown in <FIG>.

<FIG> illustrate example embodiments of valve seats having a variety of asymmetric surface features within a valve seating portion thereof. It will be appreciated by one of ordinary skill in the relevant art that such asymmetric surface features may be provided in a variety of shapes and sizes and may be tailored to provide suitable dampening, minimization or substantial elimination of pressure fluctuations under various operating conditions and parameters, and may vary in shape, size and location from the example asymmetric surface features of the illustrated embodiments of the valve seats shown in <FIG>.

In light of <FIG>, it will be readily apparent to one of ordinary skill in the relevant art that an asymmetrical surface feature may be formed in the valve seat (e.g., valve seat <NUM> of the example embodiment shown in <FIG>) in addition to or in lieu of an asymmetrical surface feature formed in the valve pin <NUM> to provide valve pin biasing functionality. Similar to the asymmetric surface feature of the valve pin <NUM>, the asymmetrical surface feature of the valve seat <NUM> may be described as an indentation, depression, notch, hole, aperture or cavity provided in one side of the tapered surface <NUM> of the valve seat <NUM>. When provided in the valve seat <NUM>, the asymmetric surface feature may be at most symmetric about only one plane of symmetry that includes the central axis Aseat of the valve seat <NUM>. In some instances, the asymmetrical surface feature may be located entirely to one side of a vertical reference plane that includes the central axis Aseat of the valve seat <NUM> and bisects the valve seat <NUM>. In some instances the asymmetrical surface feature may be bound by a reference prism, namely a semi-cylinder reference prism, defined by the vertical reference plane and a semicircular outer edge of the valve seat <NUM> at an upstream end of the asymmetrical surface feature projected along a height of the asymmetrical surface feature. In some instances the asymmetrical surface feature may be offset from a terminal end <NUM> of the valve seat <NUM>. In other instances the asymmetrical surface feature may extend to the terminal end <NUM> of the valve seat <NUM>. In some instances the asymmetrical surface feature may extend entirely through the valve seat <NUM>. In other instances the asymmetrical surface feature may terminate within the valve seat <NUM>, and thus not extend entirely through the valve seat <NUM>.

Irrespective of whether an asymmetric surface feature is provided in the valve pin <NUM>, the valve seat <NUM>, or both, the asymmetrical surface feature(s) may be formed from a material removal process, an additive manufacturing process, or other process.

When the valve pin <NUM> is displaced away from the seated configuration S, a flow of fluid interacts with the asymmetric surface feature(s) to cause an imbalance in hydrodynamic forces that disrupts an otherwise uniform flow path along a length of one side of the valve pin <NUM> to bias the end <NUM> of the valve pin <NUM> away from the central axis Aseat of the valve seat <NUM>. More particularly, during operation, the valve pin <NUM> is positioned to be exposed to a fluid having variable pressure within the fluid inlet conduit <NUM> of the valve seat <NUM> such that, when the pressure of the fluid is sufficient to overcome a control force which biases the valve pin <NUM> toward the seated configuration S, the valve pin <NUM> is forced to move away from the seated configuration S to create the annular space <NUM>, thereby allowing fluid to pass through the annular space <NUM> and to interact with the asymmetrical surface feature(s). As previously described, the asymmetrical surface feature(s) may be configured to substantially stabilize a pressure signal corresponding to the pressure of the fluid passing through the annular space <NUM> during operation by biasing the valve pin <NUM> away from the central axis Aseat of the valve seat. Absent such asymmetric surface feature(s), hydrodynamic forces remain substantially uniform around the end <NUM> of the valve pin <NUM> and it is believed that the valve pin <NUM> is therefore free to oscillate undesirably side to side within the valve seat <NUM>. Accordingly, by providing an arrangement in which fluid flow through the regulator valve assembly <NUM> causes the valve pin <NUM> to favor one side or direction over others, such oscillations can be reduced or substantially eliminated, and thereby advantageously increase service life.

Claim 1:
A valve pin (<NUM>) of a regulator valve assembly that is operable with a valve seat having a valve pin receiving aperture that defines a tapered seat surface, the valve pin comprising:
an engagement portion (<NUM>) with a tapered surface (<NUM>) having a constant draft angle selected from between about two and about five degrees, the tapered surface being configured to sealingly mate with the tapered seat surface of the valve seat when the valve pin is urged against the valve seat in a seated configuration, the tapered surface of the engagement portion being provided above and below
an asymmetrical surface feature (<NUM>) sized and shaped such that, when the valve pin is displaced away from the seated configuration and fluid flows through an annular space created between the engagement portion of the valve pin and the valve seat, unbalanced hydrodynamic forces arise from an interaction of the fluid with the asymmetrical surface feature, wherein the valve pin defines a central axis and the asymmetrical surface feature is symmetric about only one plane of symmetry that includes the central axis of the valve pin (<NUM>), and is offset from a terminal end of the valve pin and wherein the asymmetrical surface feature is an indentation, depression, notch, hole, aperture or cavity provided in a side of the valve pin; and
wherein, when the valve pin is displaced away from the seated configuration, the flow of fluid interacts with the asymmetric surface feature of the valve pin to cause an imbalance in hydrodynamic forces that disrupts an otherwise uniform flow path along a length of one side of the valve pin to bias an end of the valve pin away from a central axis of the valve seat.