Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
1999-07-16
2001-05-08
Walton, George L. (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C137S015170, C137S315410, C137S327000, C029S213100, C029S221600, C417S454000
Reexamination Certificate
active
06227225
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to fastening and unfastening an apparatus to a threaded bolt. More particularly, but not by way of limitation, this invention relates to a slip-nut apparatus and method of using the slip-nut about a threaded bolt.
In the industrial applications, pumps are used on a regular and frequent basis. The types of industrial pumps include, but are not limited to, triplex pumps, centrifuge pumps, etc. During the course of pump use, operators will find it necessary to pull valve seats. The reason for pulling out the valve seats will vary, as will be understood by those of ordinary skill in the art. For instance, the valve seat may become damaged, clogged, corroded, etc. Therefore, the valve seat may need to be repaired and/or replaced.
Regardless of the specific reason for pulling the valve seat, the operation has proved to be time consuming. In normal operation, a puller stem with attached valve seat puller is inserted into a passageway in the pump. The puller plate will abut the pump case. A wrench is threadedly disposed about the puller stem and is adjacent the puller plate. The puller stem is rotated which in turn advances the valve seat puller into engagement with the valve seat. The valve seat can then be pulled.
Additionally, the operator will then pull the second valve seat. The wrench will be backed-off by rotating the wrench thereby allowing the wrench to advanced via the threads to the desired length of the second valve seat. The advancement is accomplished by the rotational engagement of the thread means of the wrench and puller stem as is understood by those of ordinary skill in the art.
A major disadvantage of the prior art puller stems is that the threaded shaft may contain nicks, cuts, corrosion and/or other damage. Thus, in the advancement of the wrench about the puller stem, a great amount of time is consumed. As will be understood by those of ordinary skill in the art, operators want to minimize the amount of time that the pumps are out of service. Thus, the amount of time for advancing the wrench is a significant problem in the terms of productivity. Also, when the puller stem contains damaged threads, the task can be physically challenging for the operator.
Therefore, there is a need for a slip-nut that can be used in conjunction with a threaded shaft. There is also a need for an apparatus that will make it easier for operators to change valve seats from pumps. There is also a need for a method for changing valve seats in a more efficient and economical fashion.
SUMMARY OF THE INVENTION
An apparatus for pulling a valve member from a pump is disclosed. The apparatus comprises a puller stem containing external thread means and a bushing having an inner surface, and wherein said puller stem is disposed through the bushing. Also included is a first halve nut containing a first internal thread means configured to partially engaging the external thread means, and a second halve nut containing a second internal thread means configured to partially engaging the external thread means. The first end of the bushing will abut both the first halve nut and the second halve nut. Also included in one embodiment is a spring separating the two halves apart.
The apparatus further includes a sleeve having an outer portion and an inner portion, and wherein the inner portion has the threaded stem therethrough. The sleeve will engage the first halve nut and the second halve nut. In the preferred embodiment, the apparatus further comprises a first lip attached to the first halve nut and a second lip attached to the second halve nut. A collar is also included, with the collar concentrically disposed about the sleeve, the collar having an overlapping leg that forms a chamber, and wherein the first lip end of the first halve nut and the second lip end of the second halve nut is disposed within the chamber.
In the preferred embodiment, the first end of the bushing contains an angled inner shoulder and wherein the second end of the first halve contains an outer shoulder that cooperates with the angled inner shoulder and the second halve contains an outer shoulder that cooperates with the angled inner shoulder. The apparatus may further comprise a valve puller having a first end and a second end, with the first end having means for engaging the valve member and the second end engaged with the threaded stem.
The engaging means will include a prong assembly attached to the first end of the valve puller, the prong assembly being configured to insert into a pattern of openings located on the valve member.
A method of advancing a threaded stem through a nut member is also disclosed. The nut member comprises a bushing having an inner surface which contains the threaded stem therethrough, a first halve nut containing a first internal thread means configured to engage the threaded stem, and a second halve nut containing a second internal thread means configured to engage the threaded stem. The nut member also contains a sleeve having an outer portion and an inner portion, and wherein the inner portion has the threaded stem therethrough. In the preferred embodiment, the threaded stem is part of a device used to retrieve valve seats from a pump, and wherein the threaded stem has engaged at one end a valve seat puller.
The method comprises engaging the puller plate on a pump opening and advancing the first halve nut and the second half nut. Next, the first halve nut and the second half nut is abutted against the puller plate and a rotational force is exerted on the sleeve which in turn will cause the first halve nut and the second half nut to close about the threaded stem. The operator will rotate the threaded stem which in turn will cause the passing of the threads of the threaded stem through the first internal thread means and the second internal thread means thereby advancing the valve seat puller. The continued advancement will engage the first valve seat with the valve seat puller via the valve seat puller.
Next, the method may comprise exerting an upward force on the threaded stem and exerting a counter-rotational force on the sleeve which in turn will expand the first halve nut and the second half nut about the threaded stem. The first valve seat is then removed from the pump.
The method may then comprise placing the puller plate on an opening of a pump and advancing the first halve nut and the second half nut until the angled end of the first and second halve nut abut the bushing. The operator would then exert a rotational force on the sleeve which will in turn close the first and second halve nut about the threaded stem. The operator would then rotate the threaded stem which in turn will advance the valve seat puller into engagement with a second valve seat via the valve seat puller.
The method would further include exerting an upward force on the threaded stem and counter rotating the sleeve. The first halve nut and the second half nut will expand about the threaded stem so that the internal threads are no longer in engagement with threaded stem. The second valve seat may then be removed. In the preferred embodiment, the step of rotating the threaded bolt includes passing the threads of the threaded bolt through the first internal thread means and the second internal thread means.
An advantage of the present invention includes allowing placement of the slip nut at the desired position without having to threadedly advance about the threaded stem as is the case with prior art wrenches. Another advantage is if the threaded stem becomes damaged, the operator can still use the threaded stem due to the novel design herein disclosed. Yet another advantage is the novel device is economical to manufacture and maintain. Still yet another advantage is that use of the novel device will save operators significant time in the changing out of valves from pump cases.
A feature of the present invention includes having a nut member that is longitudinally separated into two halves. Another feature is that the first half nut and the second half nut can be biased to
Dominque & Waddell PLC
Walton George L.
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