Valve Reseating

Abstract

Some embodiments comprise an apparatus for reseating valves, where an eccentric, non-rotational motion is applied in a grinding or lapping process. Other embodiments comprise a micrometer that permits repeatable application of pressure against a plate when the apparatus is removed and reinstalled. In yet other embodiments, levered arms provide an expedient mechanism for positioning a reseating apparatus.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/808,765, filed on 2013 Apr. 5, by LeBoeuf, having the title “Valve Reseating,” which is incorporated by reference in its entirety as if expressly set forth herein.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates generally to valves and, more particularly, to reseating valves.

2. Description of Related Art

Through repeated use, valves may leak thereby requiring grinding or lapping of valve seats and discs to form a tight seal between the valve seats and the discs. This process of reseating valves is typically a long, repetitive, and labor-intensive process. Consequently, there exists a need in the art to improve this process.

SUMMARY

Some embodiments comprise an apparatus for reseating valves, where an eccentric, non-rotational motion is applied in a grinding or lapping process. Other embodiments comprise a micrometer or fine adjustment mechanism that permits repeatable setting of depth and application of pressure against a plate when the apparatus is removed and reinstalled. In yet other embodiments, levered arms provide an expedient mechanism for positioning a reseating apparatus. Other systems, devices, methods, features, and advantages will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a diagram showing one embodiment of an apparatus for grinding or lapping a valve seat.

FIG. 2 is a diagram showing one embodiment of a portion of the apparatus of FIG. 1 in greater detail, with FIGS. 2A, 2B, and 2C showing a perspective view of the plate motion in relation to the valve seat.

FIG. 3 is a diagram showing another embodiment of an apparatus for grinding or lapping a disc.

FIGS. 4A and 4B are diagrams showing one example of an abrasion pattern that is formed from an eccentric, non-rotational motion from one embodiment of the apparatus of FIGS. 1 through 3.

FIGS. 5A and 5B are diagrams showing a circular abrasion pattern that is formed from conventional grinding and lapping apparatuses.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Over its usable lifetime, a valve may require grinding or lapping in order to form a tight seal between a valve seat and its corresponding disc. Conventionally, reseating of valves is a long, repetitive, and labor-intensive manual process. This manual process sometimes results in uneven lapping and, depending on the number of valves that need reseating, can be a tedious task for the individual that is reseating the valves.

In an effort to address the drawbacks associated with manually reseating valves, the disclosed embodiments provide systems and methods for reseating valves. In some embodiments, an apparatus is provided for reseating valves, where an eccentric, non-rotational motion is applied in a grinding or lapping process. Although the embodiments are described as having non-rotational motion because a grinding or lapping surface (or plate) does not rotate with a spindle, those having skill in the art will appreciate that the plate does turn as a result of frictional forces at the interface. In other words, there is an angular advancement of the plate that, compared to the rotational speed of the spindle, appears non-rotational. Consequently, throughout this disclosure, it should be understood that non-rotational motion is defined to include this angular advancement of the plate.

This eccentric, non-rotational motion eliminates crowning that typically results from conventional grinding or lapping processes. In other words, the disclosed systems and processes produce a flatter or smoother sealing surface, which conventional rotational systems cannot achieve.

Also disclosed are systems and methods for installing a valve reseating apparatus, which comprises levered arms that automatically center the apparatus. For some embodiments, the levered arms also permit the reseating apparatus to be installed substantially concentric and perpendicular to the plane of the valve seat. This ability to center and maintain perpendicularity provides for more uniform application of pressure across the entire surface of the valve seat.

Additionally, some embodiments comprise a micrometer or fine adjustment mechanism that permits repeatable setting of depth and repeatable application of pressure against a plate when the apparatus is removed and reinstalled. By providing such a mechanism, a reseating apparatus can be removed from the valve and then re-installed with precision.

Having provided a general overview of several embodiments of systems and processes for reseating valves, reference is now made in detail to the description of the embodiments as illustrated in the drawings. While several embodiments are described in connection with these drawings, there is no intent to limit the disclosure to the embodiment or embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents.

FIG. 1 is a diagram showing one embodiment of an apparatus for grinding or lapping a valve seat. The embodiment of FIG. 1 shows a plate 3 that is mounted on a swivel 4, and an abrasive 5 for lapping or grinding the valve seat 13. In some embodiments, the swivel 4 is a universal joint that permits an omnidirectional range of motion. Preferably, the swivel comprises a ball-and-socket with a pin drive, thereby permitting unhampered movement of the plate 3 in all directions. As shown in FIG. 1, the swivel 4 is located axially off-center. Thus, when torque is applied by the apparatus, the swivel 4 moves in an eccentric, non-rotational manner. Additionally, the apparatus comprises a wave spring 12, which applies pressure on the plate 3. The combination of the pressure applied by the wave spring 12 and the omnidirectional range of movement provided by the swivel 4 allows the plate 3 to maintain uniform and consistent contact with the valve seat during the grinding or lapping.

The embodiment of FIG. 1 also shows the apparatus comprising levered arms 1 that are operatively coupled to an adjustment wheel 7. In combination, the levered arms 1 and the adjustment wheel 7 provide a mechanism for centering the apparatus and securely holding the apparatus perpendicular to the plane of the valve seat 13. Specifically, as shown in FIG. 1, the levered arms 1 are coupled to the adjustment wheel 7 using a pivoting mechanism such that an upward movement of the adjustment wheel 7 results in a radially-outward movement of jaws that are attached to the levered arms 1. Also, by making the levered arms 1 symmetric about the longitudinal axis of the apparatus, each of the jaws moves the same distance outwardly as the adjustment wheel 7 turns. This results in an automatic centering of the apparatus when the jaws are secured to the valve. In alternative embodiments, the levered arms 1 may include additional linkage arms 2, which permit the apparatus to be mounted on larger valves. The linkage arms 2 will locate the apparatus deeper into the valve to provide more stability in that a spindle 6 does not have to be extended further to reach the seat in larger valves. Since those having ordinary skill can extrapolate the behavior of the linkage arms 2 from the description of the levered arms 1, further explanation of this mechanism is omitted here.

The embodiment of FIG. 1 also comprises a spindle 6, a lock knob 8, and a micrometer assembly having a micrometer dial 11. The spindle 6 is set at the desired depth and locked to the micrometer assembly by the lock knob 8. The micrometer dial 11 moves the apparatus axially upward or downward in a controlled manner without rotating the spindle 6. This permits a user to uninstall the apparatus from a valve and reinstall the apparatus substantially at the same location. Thus, when an operator removes the apparatus to change the grinding or lapping abrasive 5 or inspect the valve seat 13 during reseating, the operator can simply make note of the micrometer dial 11 setting, remove the apparatus, change the abrasive 5, return to the valve seat 13, and position the plate 3 on the valve seat 13 using the previously-noted reading on the micrometer dial 11 to attain substantially the same depth and pressure.

The spindle 6 on the reseating apparatus couples to a drive motor 9 that has a speed adjuster 10. The drive motor 9 provides torque to the spindle 6, which, in turn, transfers the rotational force to the plate 3 located off center, thereby causing the eccentric, non-rotational motion of the plate 3, as described above. The speed adjuster 10 permits the user or operator to adjust the rotational speed of the drive motor 9, thereby controlling the speed of the plate's eccentric motion. For some embodiments, the speed adjuster 10 permits adjustment from near-zero (0) revolutions per minute (RPM) to approximately four hundred (400) RPM.

FIG. 3 is a diagram showing another embodiment of an apparatus for grinding or lapping a disc 14. Unlike the embodiment of FIG. 1, in which the apparatus is mounted on a valve 13 (FIG. 1), the embodiment of FIG. 3 shows the apparatus being mounted onto a stand to permit grinding or lapping of a disc 14. As one can appreciate, the apparatus provides the ability to grind or lap in an eccentric, non-rotational motion, which ameliorates some of the drawbacks of conventional grinding or lapping apparatuses that employ circular grinding patterns.

Having described various aspects of a valve reseating apparatus, a non-limiting example of its operation is provided with reference to a Safety Relief Valve (SRV) having a Stellite alloy seat to more clearly illustrate the various embodiments of the invention. For this particular example, the SRV is positioned vertically so that the plane of the valve seat is substantially parallel to the ground. An 800-grit abrasive compound 5 is applied to the plate 3, which is secured to the swivel 4. The reseating apparatus is installed onto the SRV such that the plate 3 rests on the valve seat, and the spindle 6 is locked into place by the lock knob 8. The jaws of the levered arms 1 are secured to the inner circumference of the valve by turning the adjustment wheel 7. At this point: (a) the spindle 6 of the apparatus is axially centered to the valve seat; (b) the apparatus is substantially perpendicular to the valve seat; and (c) the plate 3 is resting on the valve seat, ready for grinding or lapping. The drive motor 9 is then engaged to the spindle 6 to apply torque to the spindle 6. Thereafter, the speed is adjusted by the speed adjuster 10 to approximately seventy (70) RPM, and the plate 3 begins its eccentric, non-rotational motion. Pressure is applied to the plate 3 through the wave spring 12 by turning the micrometer dial 11. Depending on the degree to which the valve seat is to be lapped or ground, the abrasive can be changed from coarse to fine, and the micrometer dial 11 can be incrementally turned to change the pressure on the plate 3 in a controlled manner. As one will appreciate, the choice of abrasive compound 5 can depend on the amount of material to be removed, the type of material being removed, and the desired surface finish. Since these factors are known to those having skill in the art, further discussion of abrasive compound choice is omitted here.

Given this non-limiting example, one can readily see how the levered arms 1 provide a streamlined mechanism for centering and perpendicularly mounting the reseating apparatus while not obstructing the view into the valve during operation. Additionally, one can see from this non-limiting example that the eccentric, non-rotational motion of the plate 3 avoids crowning patterns that are problematic and typical of conventional reseating approaches. Furthermore, through the non-limiting example, one can appreciate that the grinding or lapping operation can be controlled with greater precision through the use of the micrometer dial 11, which controls the amount of pressure that is applied to the plate 3 through the wave spring 12. Separately, each of these features provides a marked improvement over the prior art. In various combinations, these features provide advantages that were previously difficult, if not impossible, through conventional lapping or grinding processes.

With these advantages in mind, attention is turned to FIG. 2, which is a diagram showing one embodiment of a portion of the apparatus of FIG. 1 in greater detail, with FIGS. 2A, 2B, and 2C showing a perspective view of a valve. As shown in FIG. 2, the plate 3 is situated axially off-center. Thus, as the spindle 6 (not shown in FIG. 2) imparts a torque on the plate 3, the plate 3 moves eccentrically about the axial center of the valve. Also, as shown in FIGS. 2A, 2B, and 2C, the plate 3 does not spin in relation to the rotation of the spindle as it moves eccentrically. Thus, the “Dexter” label on the plate 3, in the example of FIGS. 2A through 2C, faces in nearly the same direction during the eccentric motion while advancing the plate 3. In other words, although the spindle rotates due to the torque applied by the motor, the plate 3 experiences a non-rotational motion, which includes an angular advancement due to frictional forces.

This eccentric, non-rotational motion eliminates a crowning pattern that typically results from conventional grinding or lapping processes. In other words, the disclosed systems and processes produce a flatter or smoother sealing surface, which conventional rotational systems cannot achieve.

One non-limiting example of an abrasion pattern that results from such an eccentric, non-rotational motion is shown with reference to FIGS. 4A and 4B. By comparison, FIGS. 5A and 5B show a circular abrasion pattern that forms from a conventional grinding or lapping apparatus.

Specifically, FIG. 4A is a diagram showing an arc cross-cut hatch abrasion pattern 405. This cross-cut hatch abrasion pattern 405 results from an eccentric, non-rotational motion 410, shown in FIG. 4B. By comparison, FIG. 5A is a diagram showing a circular, concentric crowning abrasion pattern 505. The circular, concentric crowning abrasion pattern 505 results from a centered rotational motion 510 of conventional grinding or lapping processes, as shown in FIG. 5B. As shown through this comparison, the eccentric, non-rotational motion 410 avoids the typical crowning pattern 505 from conventional processes.

Any process descriptions or blocks in flow charts should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included within the scope of the preferred embodiment of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present disclosure.

Although exemplary embodiments have been shown and described, it will be clear to those of ordinary skill in the art that a number of changes, modifications, or alterations to the disclosure as described may be made. All such changes, modifications, and alterations should therefore be seen as within the scope of the disclosure.

Claims

1. An apparatus, comprising:

a spindle substantially centered about a rotational axis; and

a swivel mechanically coupled to the spindle, the swivel being located axially off center of the rotational axis.

2. The apparatus of claim 1, further comprising:

a plate mounted on the swivel, the plate being located axially off center of the rotational axis.

3. The apparatus of claim 1, the plate exhibiting eccentric, non-rotational motion when torque is applied to the spindle, the non-rotational motion including an angular advancement.

4. The apparatus of claim 2, further comprising:

an abrasive mechanically coupled to the plate, the abrasive being located axially off center of the rotational axis.

5. The apparatus of claim 2, further comprising:

a spring mechanically coupled to the plate, the spring for applying pressure to the plate.

6. The apparatus of claim 1, the swivel comprising a universal joint.

7. The apparatus of claim 1, further comprising:

means for securely holding the apparatus perpendicular to a plane of a valve seat.

8. The apparatus of claim 1, further comprising:

means for applying a torque to the spindle.

9. The apparatus of claim 1, further comprising:

means for centering the apparatus with reference to a valve.

10. An apparatus, comprising:

levered arms for securely holding the apparatus perpendicular to a grinding plane;

a spindle substantially centered about a rotational axis, the rotational axis being substantially perpendicular to the grinding plane; and

an adjustment wheel mechanically coupled to the levered arms, the adjustment wheel for adjusting the levered arms.

11. The apparatus of claim 10, further comprising:

jaws attached to the levered arms, the jaws for mounting the apparatus to a valve.

12. The apparatus of claim 11, the adjustment wheel further for moving the jaws radially outward from the rotational axis.

13. The apparatus of claim 11, further comprising:

a swivel mechanically attached to the spindle, the swivel being located axially off center of the rotational axis; and

a plate mounted on the swivel, the plate being located axially off center of the rotational axis.

14. The apparatus of claim 11, the levered arms for centering the rotational axis with reference to the valve.

15. The apparatus of claim 10, further comprising:

means for grinding in an eccentric, non-rotational motion with advance.

16. An apparatus, comprising:

a spindle substantially centered about a rotational axis;

a plate mechanically coupled to the swivel;

a spring mechanically coupled to the plate, the spring for applying pressure to the plate; and

a micrometer assembly mechanically coupled to the spindle, the micrometer assembly further being mechanically coupled to the spring, the micrometer assembly for controlling movement of the assembly parallel to the rotational axis.

17. The apparatus of claim 16, the micrometer assembly comprising a micrometer dial, the micrometer dial for indicating a relative position of the spindle with reference to a grinding surface.

18. The apparatus of claim 17, the micrometer assembly further comprising a lock knob for securing the apparatus at a fixed micrometer dial setting.

19. The apparatus of claim 16, further comprising:

means for grinding in an eccentric and non-rotational motion, the non-rotational motion including an angular advancement.

20. The apparatus of claim 16, further comprising:

means for applying a torque to the spindle.