HK1200520B - An anti-cavitation seat and a method of converting a non-anti-cavitation main valve into an anti-cavitation main valve - Google Patents

Description

Anti-cavitation seat and method for converting non-anti-cavitation main valve into anti-cavitation main valve

Technical Field

The present invention relates generally to control valves in high pressure fluid delivery systems, such as water supply systems. More particularly, the present invention relates to an anti-cavitation valve seat for use in a control valve to provide anti-cavitation and low noise characteristics.

Background

Primary valves, such as the valve shown in fig. 1, are often used in high pressure fluid transfer systems, such as water supply systems. Such main valves, generally designated by reference numeral 10, are also referred to as base valves, flow control valves, pressure reducing valves, and the like. These valves include a body 12, the body 12 defining a fluid inlet 14 and a fluid outlet 16, which are generally at opposite ends of the body 12. The inlet 14 and outlet 16 are operatively connected to tubing or the like for conveying fluid in a controlled manner. A seat 18 is disposed between the fluid inlet 14 and the outlet 16 and, in conjunction with the valve stem assembly, controls the flow of water through the valve 10. To open and close the valve 10 and control the flow of water therethrough, a cover 20 is secured to the body 12 and, together with a diaphragm 22, defines a pressure chamber 24. Fluid enters and exits the pressure chamber 24 causing the diaphragm 22 to flex outwardly toward the seat 18 and inwardly into the pressure chamber 24.

The valve stem assembly includes: a valve stem 26, the valve stem 26 extending through a diaphragm gasket 28, the diaphragm gasket 28 being on one side of the diaphragm 22; and a disc holder 30, the disc holder 30 having a disc 32, the disc 32 engaging an upper lip of the seat 18 to close the valve 10. When the pressure in the pressure chamber 24 is proportionally less than the pressure at the valve inlet 14, the pressure overcomes the force of the spring 38, which biases the diaphragm gasket 28, diaphragm 22, disc retainer 30, and disc 32 upward into the pressure chamber 24, opening the valve 10. However, when the fluid pressure in the pressure chamber 24 is equal to or greater than the pressure of the valve inlet 14 and the pressure of the valve outlet 16, as shown in FIG. 1, the fluid pressure assists the force of the spring 34 and moves the diaphragm 22, and thus the associated diaphragm washer 28, disc retainer 30 and disc 32, toward the seat 18 until the disc 32 engages the upper lip of the seat 18, as shown, to close the valve 10. Thus, the diaphragm 22, valve stem 26, diaphragm gasket 28, disc retainer 30, and disc 32 may slide relative to each other to open and close the valve. The interaction between the fluid within the valve 10, the strength of the spring 34, and the pressure applied to the pressure chamber 24 dictates the degree to which the valve 10 opens or closes, and therefore dictates the amount of fluid that can pass downstream through the valve 10.

When subjected to high pressure differentials or high flow rates, valves are often noisy and subject to excessive vibration. This is generally due to cavitation, which can range from a relatively harmless level (referred to as incipient cavitation) to a significantly more severe level that will actually damage the valves and associated piping. This can be loud enough to cause hearing loss to the equipment staff when exposed to it for extended periods of time.

Cavitation occurs when the velocity of the fluid in the valve seat area becomes excessive, producing a sudden, sharp drop in pressure, which causes the liquid to transition to a vapor state, resulting in the formation of as many as thousands of tiny bubbles. The subsequent speed reduction and pressure increase, which occurs after the valve seat area when the pressure increase state is restarted, causes these steam bubbles to collapse at a rate many times per second. When this occurs in close proximity to any metal surface, damage may occur. Over time, this may lead to valve failure due to vibration and/or corrosion. Minimizing or eliminating these conditions, which adversely affect the operation and useful life of the valve, continues to be one of the most serious challenges encountered in the daily operation of water distribution systems, such as municipal water systems.

To overcome the adverse effects of the valve's orifice-forming (orifice) action, valves are typically designed such that the fluid flow through the valve is broken up into a large number of small fluid flows that are then directed through convoluted pathways, thereby creating energy losses in the fluid. This design is referred to as curved fluid flow redirection. Valve assemblies are known, such as those manufactured by Ross valve manufacturing Company inc, which use alignment plates for dampening vibrations, pressure fluctuations, cavitation, and noise. For example, the upstream corrugated plate can be selectively slid into place to control flow. A downstream plate with multiple holes produces a large number of jets, which reduces the pressure flow through the set of plates. However, the number and size of the orifices in the plate, the number of plates, and their spacing are determined by the fluid flow rate, and varying flow rates may render such orifice plates ineffective.

Other valve assemblies are also known in which a cross-over tank with holes forms a tortuous fluid path. For example, Singer valve Inc. provides an anti-cavitation trim having an interconnected can with a plurality of small circular holes, which overcomes many of the existing problems of "stacked" plate designs. In such a two-canister design as the Singer assembly, one canister acts as a seat while the other canister replaces the components of the valve stem assembly and is moved up and down relative to the bottom canister by the valve stem to open and close the main valve and create a tortuous fluid path between the orifices of the two canisters. The Singer valve is effective in substantially eliminating noise and cavitation. However, such valve assemblies are prone to fouling or clogging due to the small circular holes used in the canister. In practice, the fluid must typically be filtered before passing through the Singer valve assembly. Moreover, fluid exiting the canister of the Singer valve assembly is directed against the housing wall, causing corrosion.

While effective in reducing noise and cavitation, these devices are not optimal. The main disadvantage of these designs is the significant reduction in valve capacity, making these valves unusable in some situations. These valve designs also require relatively complex and expensive manufacturing and assembly.

Another problem encountered with known anti-cavitation valve assemblies disposed within the seating area of a main or base valve is that they cannot use the components of the same valve stem assembly of existing valve assemblies. Thus, when retrofitting an existing main or base valve, standard valve seats, disk guides, valve stems, disk holders, diaphragms, diaphragm gaskets, etc. must be replaced with new components. Preferably and advantageously, customers desire to add anti-cavitation features to existing main or base valves. It would be particularly preferred and advantageous when customers are able to use their existing valve stem assemblies and simply replace the standard seat with an anti-cavitation seat.

Therefore, there is also a need for an anti-cavitation valve assembly that uses components of the same valve stem assembly of an existing valve and can be used to retrofit an existing valve. The present invention fulfills these needs and provides other related advantages.

Disclosure of Invention

The present invention relates to an anti-cavitation seat positionable between an inlet and an outlet of a main valve and associated with a non-cavitation-proof disc of a valve stem assembly for engagement with the disc upon opening and closing of fluid flow between the inlet and the outlet of the main valve. Thus, the anti-cavitation seat of the present invention can be inserted in place of a standard non-anti-cavitation seat to provide the main valve with anti-cavitation features.

The anti-cavitation seat generally includes a first wall extending from a base and having a plurality of spaced apart apertures formed therein. A second wall also extends from the base and is spaced from the first wall to define an outer chamber between the first and second walls. The second wall also defines an interior chamber of the seat. The second wall has a plurality of spaced apart apertures formed therein. Preferably, the apertures of the first and second walls are offset from each other so as to form a tortuous fluid flow path between the apertures of the first wall and the apertures of the second wall.

The apertures of the second wall are arranged to direct fluid into the interior chamber such that fluid flow from the apertures of the second wall converges in the interior chamber. In a particularly preferred embodiment, the apertures of the first and second walls are elongate slots.

A hollow post extends from the base into the interior chamber. The post includes an aperture formed therein to allow fluid to pass through the post into the interior chamber. Typically, the post apertures and the second wall apertures are arranged such that fluid inflowing from at least a plurality of the post apertures and the second wall apertures converges in the interior chamber. Thus, at least a plurality of the apertures of the post and the apertures of the second wall are substantially aligned with one another. The post may include an opening for receiving a valve stem of a valve stem assembly of a main valve therein.

The seat includes a peripheral lip at the upper ends of the first and second walls, the peripheral lip configured to engage a disc of the valve stem assembly to close fluid flow through the main valve.

To convert a non-cavitation-preventive main valve into a cavitation-preventive main valve, a main valve is provided having a fluid inlet and a fluid outlet and a non-cavitation-preventive seat disposed between the fluid inlet and the fluid outlet and aligned with a non-cavitation-preventive stem assembly disk. The non-cavitation-prevention seat is removed and the cavitation-prevention seat is mounted in its place. The non-cavitation stem assembly disc and the cavitation prevention seat cooperatively function to open and close fluid flow between the inlet and the outlet of the main valve.

Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

Drawings

The figures illustrate the invention. In the drawings:

FIG. 1 is a cross-sectional view of a prior art main valve having a non-anti-cavitation seat and valve stem assembly;

FIG. 2 is a cross-sectional view of a main valve according to the present invention similar to FIG. 1, but with an anti-cavitation seat located between the inlet and outlet of the main valve;

FIG. 3 is a partial cut-away perspective view of the anti-cavitation seat of FIG. 2;

FIG. 4 is a cross-sectional view taken generally along line 4-4 of FIG. 3 illustrating fluid flow through the anti-cavitation seat in accordance with the present invention;

FIG. 5 is a perspective view, partially in section, of another anti-cavitation seat embodying the present invention;

FIG. 6 is a cross-sectional view of a main valve having the anti-cavitation seat of FIG. 5 disposed therein, and in an open state; and

FIG. 7 is a cross-sectional view of the main valve of FIG. 6 in a near closed state.

Detailed Description

As shown in the accompanying drawings for purposes of illustration, the present invention is directed to an anti-cavitation seat, generally indicated by the reference numerals 100 and 200, which provides anti-cavitation and noise reduction features to a main valve 10.

Referring to FIG. 2, a main valve 10 (also sometimes referred to as a base valve, fluid control valve, or pressure reducing valve) is shown similar to the main valve of FIG. 1. Accordingly, the main valve 10 includes a body 12, the body 12 having a fluid inlet 14 and a fluid outlet 16. The cap 20 and the flexible diaphragm 22 cooperatively form a pressure chamber 24. The valve stem assembly comprising the slidable valve stem 26, diaphragm washer 28, disc retainer 30, disc 32 and biasing spring 34 is standard and conventional, as shown and described above with reference to fig. 1. It should be appreciated that the components of the standard valve stem assembly do not have anti-cavitation or noise reduction features. In fact, when using a standard, non-anti-cavitation seat 18 (as shown in FIG. 1), the main valve 10 is subject to large pressure drops and fluid flow, which may create cavitation and noise. These may damage the components of the valve 10.

As noted above, the prior art uses either an orifice plate disposed upstream and/or downstream of the main valve 10, or a mating orifice canister disposed between the inlet 14 and the outlet 16 of the main valve 10, instead of the standard non-cavitation valve stem assembly 26-34 and the seat 18, and which slides relative to each other to create a tortuous flow path to separate fluid flow and force, these systems being complex and expensive. Moreover, the prior art assemblies and systems are not suitable for retrofitting existing main valves. Moreover, they do not utilize standard components within the main valve 10 per se, such as the components 26-34 of the valve stem assembly.

Thus, as shown in FIG. 2, the present invention overcomes these obstacles and disadvantages by replacing the standard non-cavitation-resistant seat 18 with a seat 100 having cavitation-resistant and noise-reducing features. Such an anti-cavitation seat 100 is shown between the inlet 14 and the outlet 16 of the main valve 10 in place of the standard seat 18. As will be appreciated by those skilled in the art, the anti-cavitation seat 100 of the present invention enables an existing valve assembly to be easily and cost-effectively retrofitted, while using the existing valve stem assembly components 26-34, by simply replacing the seat 18 of the valve 10, the anti-cavitation seat 100 in cooperation with the valve stem assembly (and in particular the disc 32) opening and closing the main valve 10, as more fully described herein.

Referring now to fig. 3 and 4, the anti-cavitation seat 100 is shown as a generally cylindrical body. The seat 100 includes a base 102 from which a first wall 104 having a plurality of spaced apart inlet apertures 106 formed therein projects. The first wall 104 extends upwardly to a peripheral lip 108, the peripheral lip 108 being arranged for engagement with the valve stem assembly, more particularly with the disc 32 of the valve stem assembly, for closing the main valve 10.

Although the aperture 106 may have a variety of configurations, in a particularly preferred embodiment, the aperture 106 comprises an elongated slot having a length greater than a width. The elongated slot 106 preferably extends along a substantial portion of the length or height of the first wall 104 and is of a diameter capable of allowing a substantial volume of fluid to flow therethrough. Typically, as shown in fig. 3 and 4, the inlet apertures 106 are spaced apart from one another around the entire periphery of the first wall 104, e.g., substantially equally spaced apart from one another. However, the present invention contemplates other configurations as needed or desired. One advantage of using elongated slots as the inlet apertures 106 is that relatively large elongated slots 106 are less prone to clogging, whereas with smaller circular apertures or the like would be prone to clogging.

With continued reference to fig. 3 and 4, the second wall 110 is spaced apart from and extends upwardly from the base 102 generally concentric with the first wall 104. The second wall 110 also has a plurality of inlet apertures 112 formed therein. These inlet apertures 112 are generally similar to those described above with respect to the first wall apertures 106. Thus, they are generally and preferably elongated slot structures and extend substantially the length or height of the second wall 110, as shown. Also, the inlet apertures 112 are spaced apart from one another around the periphery of the wall 110. Generally, the inlet apertures 112 of the second wall 110 are similar to those described above for the first wall apertures 106, except that they are axially offset from the outer slots 106, such that fluid flow is diverted in an indirect path between the outer and inner apertures 106 and 112.

An initial or outer chamber 114 is created between the first wall 104 and the second wall 110. The outer chamber is defined by the first wall 104 and the second wall 110, and its dimensions are dictated by the spacing between the first and second walls 104 and 110 and the height of the first and second walls 104 and 110. Thus, the outer chamber 114 is generally defined by the inner surface of the wall 104 and the outer surface of the wall 110. Generally, the outer chamber 114 is generally cylindrical and annular in cross-section, as shown in FIG. 4.

The seat 100 and main valve 10 of the present invention are typically used in high pressure environments, such as municipal water supply lines and the like. Referring to fig. 4, when water or other fluid comes into contact with the seat 100, it flows through the inlet aperture 106 of the first wall 104, as indicated by the directional arrows in fig. 4. The apertures 106 of the first wall 104 and the apertures 112 of the second wall 110 are preferably offset from each other, as shown in fig. 3 and 4, so that fluid must flow into the outer chamber 114 and then through the inlet apertures 112 of the second wall 110. This creates a tortuous path that slows the velocity of the fluid and removes energy from the fluid.

The fluid then flows from the inlet port 112 of the second wall 110 into the interior chamber 116 of the seat 100, the interior chamber 116 being defined by the interior surface of the second wall 110. Because the apertures 112 of the second wall 110 are spaced apart from each other and formed along the periphery of the second wall 110, the fluid is directed toward the center of the interior chamber 116 where it converges on itself and loses additional energy and force. This converging fluid region within the interior chamber 116 directs the fluid to itself, where any possible cavitation may occur away from the component surface. The convergence of the fluid flow also dissipates energy, which can create the greatest pressure drop in the interior chamber 116, rather than at the outlet of the seat or in other areas within the main valve 10. By having a smaller pressure drop area across the seat 100, the possibility of creating a damaging cavitation condition is reduced or eliminated.

With continued reference to fig. 3 and 4, in a particularly preferred embodiment, the anti-cavitation seat 100 further includes a hollow post 118, the hollow post 118 extending upwardly from the base into the interior chamber 116. Generally, as shown, the hollow post 118 is generally centered within the seat 100, thus forming a central axial chamber 120. The chamber 120 is accessible through an aperture 122 formed in the base 102. Typically, the post 118 also includes an aperture 124 formed at a top end thereof, the aperture 124 being configured to allow the valve stem 26 of the valve stem assembly to be slidably inserted therethrough, as shown in FIG. 2.

Fluid holes 126 are formed in the walls of the column 118 as shown in fig. 3 and 4. These apertures 126 are preferably elongated slots, as shown. The bore 126 is formed around the periphery of a wall 128 of the post 118 to communicate fluid between the central axial chamber 120 and the interior chamber 116 of the hollow post 118. Thus, when fluid encounters the seat 100, the fluid enters the central axial chamber 120 of the hollow column 118 through the holes 122 in the base 102 and exits the radial holes 126 of the stem wall 128 to enter the interior chamber 116.

As shown in fig. 4, the fluid exiting the hollow post 118 through the apertures 126 converges with the fluid exiting the apertures 112 of the inner second wall 110, thereby dissipating the fluid energy and allowing the maximum pressure drop to occur in the inner chamber 116, rather than at the outlet of the seat or at other areas of the main valve 10. At least some of the apertures 126 of the post 118 may be generally aligned with some of the apertures 112 of the inner second wall 110 in order to maximize this effect. This is represented by the directional fluid flow regions in fig. 4 that meet in the interior chamber 116 of the cartridge 100. Typically, post 118 extends to lip 108 or below lip 108, and upper aperture 124 is substantially closed by valve stem 26 so as to force fluid through peripheral aperture 126 of post 118. The plurality of apertures 126 formed around the post 118 also allow additional fluid to converge in the interior chamber 116, thereby increasing the overall volume of fluid passing through the valve. This enables an increase in flow capacity without degrading the anti-cavitation properties, which cannot be achieved by prior art anti-cavitation designs.

Referring again to fig. 2, with the main valve 10 open (as shown) and the valve stem assembly (particularly the disc 32) unseated from the seat 100, fluid flowing from the inlet 14 of the valve 10 encounters the anti-cavitation seat 100, as described above, and as the fluid flows from the seat 100 through the valve 10 and out the outlet 16 of the main valve 10, energy is dissipated and cavitation damage is reduced or eliminated by causing the fluid flow to diverge and force the fluid to converge on itself (as described above). However, when the valve stem assembly is lowered such that the disc 32 engages the upper lip 108 of the anti-cavitation seat 100, fluid cannot flow from the inlet 14 to the outlet 16 of the main valve 10.

Referring now to fig. 5-7, although the anti-cavitation seat 100 of fig. 2-4 is shown as being generally cylindrical, one skilled in the art will appreciate that other configurations are possible which achieve the same advantages and objectives of the present invention. For example, in FIG. 5, an anti-cavitation seat 200 is shown, the anti-cavitation seat 200 having a generally frustoconical or bowl-shaped configuration, but otherwise being similar in structure to the anti-cavitation seat 100 shown in FIG. 3. The conical profile configuration has the advantage of distributing the incoming flow area more evenly into the seat chamber cavity. The conical profiles used in prior art anti-cavitation designs (e.g., Singer) do not take advantage of the conical features without reducing the effectiveness of their anti-cavitation properties.

The anti-cavitation seat 200 includes a base 202 from which first and second spaced apart walls 204 and 210 extend, each of the first and second walls 204 and 210 having spaced apart fluid apertures 206 and 212 formed therein, generally as described above. The spaced apart walls 204 and 210 create a first outer chamber 214 and the inner second wall 210 forms an inner chamber 216. Walls 204 and 210 extend upwardly from base 202 to a peripheral upper lip 208, which peripheral upper lip 208 is configured to engage a valve stem assembly, as described above. A hollow post 218 extends upwardly from the base 202 into the interior chamber 216 and has an inlet 222 formed in the base 202, the inlet 222 providing fluid access to a central axial chamber 220, the central axial chamber 220 generally having an upper bore 224 into which the valve stem 26 of the valve stem assembly may be inserted. Spaced apart perimeter holes 226 are formed in the wall 228 of the post 218. The general arrangement and function of these components and structures is similar to that described above with respect to anti-cavitation seat 100 (shown and described with reference to fig. 3 and 4). However, in this example, reference numerals are increased by 100, e.g., 100 is changed to 200, for the purpose of illustrating and explaining the different structure of the anti-cavitation seat 200.

Referring now to fig. 6, there is shown a main valve 10 having the anti-cavitation seat 200 of fig. 5 mounted therein for the main valve 10. A standard non-cavitation prevention valve stem assembly has been moved upwardly away from the seat 200 to open the valve 10 and allow fluid flow from the inlet 14 to the outlet 16 of the main valve 10. The breakup in the fluid anti-cavitation is created by the seat 200, as described above.

However, when the fluid pressure within the pressure chamber 24 is proportionally less than the valve inlet 14 pressure and proportionally greater than the outlet 16 pressure by means of the spring 34, the valve stem assembly moves downward toward the anti-cavitation seat 200, as shown in FIG. 7. In fig. 7, the main valve 10 is only partially open, for example about ten percent open. Thus, fluid is still able to flow through the anti-cavitation seat to the outlet 16. However, as the fluid pressure within chamber 24 increases, the valve stem assembly will move downward into contact with anti-cavitation seat 200 such that disk 32 contacts lip 208, or any other sealing component of the valve stem assembly contacts lip 208 or an upper sealing portion of anti-cavitation seat 200, to close valve 10 and prevent fluid flow between inlet 14 and outlet 16.

It will be appreciated that there are advantages in ease and ease of retrofitting and simple and inexpensive arrangement of parts by simply removing the standard non-cavitation-preventing seat 18 and replacing it with the anti-cavitation seat 100 or 200 of the present invention, while retaining the other components of the main valve 10, particularly the standard non-cavitation-preventing components of the valve stem assembly. Not only is retrofitting an existing valve advantageous, but it is also advantageous to incorporate the anti-cavitation seat 100 or 200 of the present invention into a new valve while retaining the standard components of the valve 10.

Although several embodiments have been described in detail for purposes of illustration, various modifications may be made without deviating from the scope and spirit of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims.

Claims (12)

1. An anti-cavitation seat fixedly positionable between an inlet and an outlet of a main valve and associated with a movable non-cavitation-prevention disc of a valve stem assembly for engagement therewith upon opening and closing of fluid flow between the inlet and the outlet of the main valve, said anti-cavitation seat comprising:

a first wall having a plurality of spaced apart apertures formed therein;

a second wall in fixed relation to and spaced from the first wall along at least a portion thereof and defining an interior chamber and an exterior chamber between the first wall and the second wall, the second wall having a plurality of spaced apart apertures formed therein;

a hollow post extending from the base into the interior chamber in spaced relation to the second wall, the hollow post and the second wall at least partially defining the interior chamber therebetween;

a peripheral lip at the upper ends of the first and second walls, the peripheral lip configured to engage the non-cavitation-preventing disc of the valve stem assembly when the non-cavitation-preventing disc is moved to the closed position to prevent fluid flow between the inlet and the outlet of the main valve;

wherein a tortuous fluid flow path is formed between the outside of the bore of the first wall and the inside of the bore of the second wall; and

the apertures of the second wall are arranged to direct fluid into the interior chamber such that fluid flow from the apertures of the second wall converges in the interior chamber.

2. The anti-cavitation seat as claimed in claim 1, wherein: the aperture of the first wall is an elongated slot.

3. The anti-cavitation seat as claimed in claim 1, wherein: the aperture of the second wall is an elongated slot.

4. The anti-cavitation seat as claimed in claim 1, wherein: the aperture of the second wall is offset from the aperture of the first wall.

5. The anti-cavitation seat as claimed in claim 1, further comprising: a base from which the first and second walls extend.

6. The anti-cavitation seat as claimed in claim 1, wherein: the hollow post includes a hole formed therein to allow fluid to pass through the post into the interior chamber.

7. The anti-cavitation seat as claimed in claim 6, wherein: the holes of the hollow column and the holes of the second wall are arranged such that fluid inflowing from at least a plurality of the holes of the hollow column and the holes of the second wall converge.

8. The anti-cavitation seat as claimed in claim 7, wherein: at least a plurality of the holes of the hollow column and the holes of the second wall are generally aligned with respect to each other such that fluid flowing out of the holes of the hollow column is generally directed toward fluid flowing out of the holes of the second wall.

9. The anti-cavitation seat as claimed in claim 6, wherein: the bore of the hollow post is capable of increasing the flow through the anti-cavitation seat when the valve is open without degrading the anti-cavitation properties of the anti-cavitation seat.

10. The anti-cavitation seat as claimed in claim 1, wherein: the hollow post includes an opening for receiving a valve stem of a valve stem assembly of a main valve therein.

11. A method of converting a non-anti-cavitation main valve into an anti-cavitation main valve, comprising the steps of:

providing a main valve having a fluid inlet and a fluid outlet and a non-cavitation-preventing seat disposed between the fluid inlet and the fluid outlet and aligned with a non-cavitation-preventing stem assembly disc, the non-cavitation-preventing seat and the non-cavitation-preventing stem assembly disc cooperatively acting to open and close fluid flow between the fluid inlet and the fluid outlet of the main valve;

disassembling the non-anti-cavitation seat; and

an installation anti-cavitation seat, the anti-cavitation seat comprising: a first wall having a plurality of apertures and a second wall in fixed relation to the first wall, spaced from the first wall along at least a portion thereof and having a plurality of apertures, the first and second walls defining a tortuous fluid flow path from the apertures of the first wall to the apertures of the second wall, and the apertures of the second wall being arranged such that the fluid streams converge in an internal chamber defined by the second wall; a hollow column extending from the base into the interior chamber in spaced relation to the second wall and having an aperture for directing fluid from an interior of the hollow column into the interior chamber so as to converge with at least a portion of the fluid directed into the interior chamber through the aperture of the second wall; the anti-cavitation seat further includes a peripheral lip at an upper surface of the first and second walls, the peripheral lip configured to engage a non-cavitation stem assembly disc to open and close fluid flow between a fluid inlet and a fluid outlet of the main valve.

12. The method of claim 11, wherein: the apertures of the first wall and the apertures of the second wall of the anti-cavitation seat include spaced apart elongated slots.