The present disclosure generally relates to a valve assembly for use in a reciprocating compressor cylinder. More specifically, the present disclosure describes an improved clamping arrangement for a valve assembly used in a reciprocating compressor cylinder.
Referring to
Generally speaking, and as will be readily appreciated by one of ordinary skill, the compressor 10 may include a cylinder 12, in which one or more pistons 14 are slidably disposed for reciprocating movement therein. A piston rod 16 is fixed at one end to the piston 14, and at an opposite end to a crosshead 18 that may be reciprocally guided for movement in a straight line. Rotary movement of a drive shaft 19 is transmitted to the crosshead 18 by way of a crank 20, which may be connected to a rod 22. As the crank 20 turns, it causes the rod 22 to move along a path that includes both horizontal and vertical components of motion. The rod 22 is coupled to the crosshead 18 in a manner that enables the crosshead 18 to move due to the manner in which the crosshead 18 is guided.
In use, the compressor 10 may be of the double acting type, in which compression chambers 25A, 25B are formed in the cylinder 12 on either side of the piston 14. Each of the compression chambers 25A, 25B is provided with a pair of valve assemblies 50 (for example, the valve assemblies 50 may be an inlet valve and an outlet valve, also known as a suction valve and a discharge valve) located within a valve cage 40 disposed on the cylinder 12 of the compressor 10. As will be generally appreciated, the cylinder 12 can include any number of valve assemblies 50. Movement of the piston 14 in a first direction causes gas at a suction pressure to be introduced by way of the inlet valve into a first compression chamber 25A. At the same time, the gas present in the second compression chamber 25B is compressed and discharged at a discharge pressure by way of the outlet valve.
As previously mentioned, the valve assemblies 50 may be a discharge valve or a suction valve. Referring to
Referring to
While a gland clamping arrangement as illustrated has proven acceptable in the past, one problem with using a valve gland 54 to provide the desired clamping and sealing arrangement for the valve assembly 50 is that it can result in a relatively complicated geometrical and dimensional dependency between the dimensions of the valve assembly 50, the valve gland 54, the valve cover 56 and the valve cage 40. Such geometrical and dimensional dependency can result in sealing problems should the tolerances of the individual components not be adequately controlled. In some applications, for example, in liquid natural gas (LNG) regasification and (re)liquefaction plants, where cold process gases are being compressed, this geometrical dependency causes issues that can lead to ineffective sealing between engagement surfaces. This, in turn, can require rework, frequent replacement of seals, and/or can require that a more complex seal or a more complex hold down solution be employed. Alternatively, or in addition, since very tight dimensional tolerances must be held for the various components, increased manufacturing costs can be incurred.
In addition, conventional construction of a valve assembly 50 employing a valve gland 54 to clamp the assembly to the cylinder 12 can result in a relatively more expensive system. High forces acting on the valve gland 54 require the valve gland 54 to be engineered to have a certain minimum wall thickness. In addition, forming the necessary openings 55 in the walls of the valve gland 54 to permit gas flow may result in the valve gland 54 having a more complex design than may be desired.
One alternative solution (not shown) has been to incorporate separate hold down bolts that protrude through the valve cover to press directly down onto the valve gland. However, by applying separate hold down bolts in the valve cover to press down on the valve gland requires the incorporation of a flat seal for the valve cover and separate seals for each of the hold down bolts which are protruding through the valve cover. In addition, the valve seal results in a complex and expensive solution since all of the bolts have to be tensioned and sealed individually and can fail individually. Furthermore, there is a risk associated with the bolts loosening over time.
In view of the foregoing, it would be desirable to provide a new and improved clamping method for a valve assembly used in a compressor.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.
Disclosed herein is an improved clamping device for securing a valve assembly to a cylinder in a reciprocating compressor. The valve assembly at least partially disposed within a valve cage sealed from the surrounding environment by a valve cover. The clamping device including a clamping mechanism for securing the valve assembly to the cylinder, wherein the clamping mechanism is free of contact with the valve cover.
The clamping mechanism may include a clamping ring for securing the valve assembly directly to the cylinder. The clamping ring may be configured to extend around, and contact, a perimeter portion of the valve assembly. The clamping ring may include a plurality of openings for receiving a plurality of fasteners for securing the clamping ring, and hence the valve assembly, to the cylinder.
Alternatively, the clamping mechanism may be integrated with the valve assembly. The clamping mechanism may include a clamping flange that is integral to the valve assembly, the clamping flange for securing the valve assembly directly to the cylinder. The integrated clamping flange may include a plurality of openings for receiving a plurality of fasteners for securing the integrated clamping flange, and hence the valve assembly, to the cylinder.
The plurality of fasteners may be elongated fasteners that extend adjacent to, but do not contact, the valve cover.
In an alternate embodiment, the present disclosure is directed to a valve clamping assembly for securing a valve assembly (i.e., suction or discharge valves) to a cylinder of a reciprocating compressor. The valve clamping assembly may include a valve assembly at least partially disposed in a valve cage, a valve cover for sealing the valve cage from a surrounding environment, a clamping mechanism for clamping the valve assembly to the cylinder, the clamping mechanism having a plurality of openings, and a plurality of fasteners extending into or through the plurality of openings for directly securing the clamping mechanism to the cylinder for securing the valve assembly to the cylinder, wherein the clamping mechanism and the plurality of fasteners have no contact with the valve cover.
The clamping mechanism may include a clamping ring for securing the valve assembly directly to the cylinder. The clamping ring may be configured to extend around a perimeter of the valve assembly. Alternatively, the clamping mechanism may be integrated into the valve assembly. The integrated clamping flange may secure the valve assembly directly to the cylinder.
The present disclosure further discloses a method for securing a valve assembly to a cylinder of a reciprocating compressor. The method may include the steps of placing the valve assembly into a valve cage, securing the valve assembly to the cylinder via a clamping mechanism having a plurality of openings for receiving a first plurality of fasteners, and securing a valve cover to the valve cage, the valve cover having a second plurality of openings for receiving a plurality of cover fasteners, wherein the clamping mechanism and the first plurality of fasteners have no contact with the valve cover.
The clamping mechanism may be a clamping ring that extends around a perimeter of a valve assembly. Alternatively, the clamping mechanism may be a flange integrated into a valve assembly.
By way of example, specific embodiments of the disclosed device will now be described, with reference to the accompanying drawings, in which:
A device and method in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the device and method are shown. The disclosed device and method, however, may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the device and method to those skilled in the art. In the drawings, like numbers refer to like elements throughout.
The present disclosure describes a clamping arrangement for a valve assembly used in reciprocating compressors. More specifically, the present disclosure describes a clamping arrangement for a valve assembly used in, for example, a compressor cylinder. Referring to
The present disclosure achieves the desired results by incorporating a separate clamping mechanism 120, 220 that has no contact or direct interaction with the valve cover 56. As such, the valve gland 54 (
Alternatively, referring to
In this manner, a new improved clamping method for valve assemblies is disclosed, which is independent of any clamping force provided by or guided through the valve cover 56, but instead utilizes a separate clamping ring 122 or an integrated clamping flange 222 including a plurality of openings spaced about the perimeter of the valve assembly 50 to provide a desired hold down force. The clamping ring 122 or an integrated clamping flange 222 is, in the illustrated embodiments, completely free from any physical contact with the valve cover 56.
In use, the clamping ring 122 or integrated clamping flange 222 may be secured to the cylinder 12 by a plurality of fasteners 130. The fasteners 130 can be any fasteners now known or hereafter developed including, but not limited to, studs/bolts and nuts (as generally shown), screws, etc. Moreover, referring to
In use, the fasteners 130 may supply a desired hold down force to secure the valve assembly 50 to the cylinder 12. In the illustrated embodiments, the fasteners 130 may be positioned in a circular pattern around the perimeter of the valve assembly 50 within the gas filled passage area of the cylinder 12. As mentioned, the fasteners 130 are also free from any physical contact or engagement with the valve cover 56.
In this manner, the hold down force applied to the valve assembly 50 may be directly applied by a separate clamping mechanism 120 associated with the outer perimeter of the valve assembly 50 to secure the valve assembly 50 directly to the cylinder 12. Alternatively, the hold down force applied to the valve assembly 50 may be directly applied by an extended, integrated circumferential flange 222 having a circular hole pattern, through which the aforementioned hold down fasteners 130 extend and on which a plurality of nuts (or bolt heads) may press down. This extended circumferential flange 222 may be an integral part of the valve assembly 50.
According to the present disclosure, the improved clamping arrangement 100, 200 eliminates the clamping function of the valve cover 56, and instead directly applies a clamping arrangement to the valve assembly 50. As previously noted, the improved clamping arrangement may require less precise dimensional tolerances of parts, easier assembly, increased reliability of the different seals, minimizes the required space and thus can produce a smaller and lighter cylinder.
One or more sealing elements may be disposed between the valve assembly 50 and the cylinder 12, more specifically, surface 13 formed on the cylinder 12. The seal may be any conventional seal now known or hereafter developed. For example, the seal may be a conventional circular seal that sits between the cylinder 12 and the bottom surface of the valve assembly adjacent to the perimeter of the valve assembly. Referring to
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
While certain embodiments of the disclosure have been described herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
This application is a continuation of International Application No. PCT/IB2016/057624, filed on Dec. 14, 2016, the entire contents of which is hereby incorporated by reference.
Number | Date | Country | |
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Parent | PCT/IB2016/057624 | Dec 2016 | US |
Child | 16431918 | US |