Packing Gland

The present invention pertains to stuffing box assemblies, and more specifically, to an improved structure allowing easier access to the adjusting means by which the gland is tightened against the seal between a shaft and housing. The invention is particularly applicable to valve assemblies, wherein the necessity for mounting a valve actuator closely adjacent to the stuffing box makes access to such adjusting means difficult. However, various principles of the invention can also be applied to other types of apparatus, and will be particularly useful in those in which access to the adjusting means for a stuffing box gland is made difficult because of adjacent apparatus.

U.S. Pat. No. 2,711,333 and U.S. Pat. No. 3,223,425 illustrate generally what is probably the most common arrangement for providing adjustment of a packing gland for a stuffing box assembly. As shown in those patents, the gland is provided with a radial flange, and one or more studs mounted in the housing extend through that flange. On the opposite side of the flange from the housing, each stud is provided with an adjustable nut which, when threaded inwardly toward the housing, urges the gland ahead of it thus compressing the seal. U.S. Pat No. 860,035 illustrates a variation for an apparatus in which there are two generally oppositely directed glands arranged such that both of them can be tightened by a common set of studs and adjusting nuts.

One of the primary difficulties in accommodating the general scheme illustrated in U.S. Pat. No. 2,711,333 and U.S. Pat. No. 3,223,425, discussed above, to valve assemblies is that which occurs when a valve actuator must be mounted on the housing closely adjacent the stuffing box. This requires that some portion of the housing, or an appendage thereto extend past the stuffing box and the gland adjusting system while still allowing access to the latter. One approach to this problem is illustrated in U.S. Pat. No. 4,156,520. As shown in this patent, the actuator is not mounted directly on the neck of the valve body or housing, but rather, is mounted on supports spaced laterally outwardly from the valve stem and valve neck, the latter being truncated. This approach has several disadvantages. In the first place, it is expensive in that it requires a greater amount of material and machining thereof to form the actuator support structure, whether it is formed integrally with the valve housing or attached thereto. Furthermore, access to the actuating nuts for adjusting the packing gland is still relatively difficult in that the nuts must be reached through windows formed by the actuator support structure, and in some cases, parts of the actuator and/or other ancillary apparatus may even overhang these windows.

Another approach is illustrated in U.S. Pat. No. 2,587,474. In this structure a sleeve which bears on the upper end of the packing gland to force it downwardly is threaded about the exterior of the neck portion of the housing. This arrangement is also undesirable, particularly in valve assemblies, in that it requires external machining of the neck and a more extensive gland structure, including a bulky sleeve which consumes additional space about the exterior of the neck.

The present invention provides a stuffing box and gland adjusting system which not only allows easy access to the adjusting means, even where an actuator or like apparatus must be mounted closely adjacent the housing, but also minimizes the amount of material and structure which must be provided in the general valve neck/actuator support area, and further without compensatory enlargement or embelishment of the structure of the gland itself.

One important feature of the present invention is that the housing is provided with one or more flanges extending generally laterally outwardly from the valve neck, and spaced longitudinally along the valve neck from the main body portion of the valve housing. The engagement portion of the gland adjusting means, e.g. nut or screw head, which must be engaged and rotated to tighten the packing is located in the space thus provided, i.e. longitudinally between the aforementioned housing flange and the main body portion of the valve housing, whereas the actuator is mounted on a second flange located on the opposite side of the first mentioned flange from the main body portion of the housing.

Another important feature of the assembly of the present invention is that, preferably between the housing flange means and actuator mounting flange described above, the housing is provided with a slot opening radially through the valve neck and communicating with the bore of the valve neck. The packing gland, which has a compression portion extending into the bore for engagement with the seal, also has a flange extending laterally outwardly through the slot for engagement with its adjusting means.

The structure described above allows for the elimination of bulky lateral actuator supports or the like which not only increase the expense of the apparatus but interfere with access to the engagement portion of the adjusting means. Such access is further facilitated by the fact that said engagement portion is located on the opposite side of the housing flange from the actuator.

Although these features can be employed with adjusting means in which a stud is fixedly secured to the gland flange, loosely extended through the housing flange, and threadedly engaged by an adjusting nut, even further advantages are achieved by providing the adjusting means in the form of a screw threadedly connected to the gland flange, loosely extending through the housing flange, and having a head which abuts the latter flange to not only serve as the aforementioned engagement portion, but also to cooperate with the housing flange in limiting movement of the screw generally longitudinally away from the seal. Accordingly, when the screw is rotated in a direction which would tend to move it away from the seal, the gland will instead be moved toward the seal. However, because the screw need not move, it will not advance into the space between the housing flange and the main body of the valve housing, and this simplifies spacing problems.

Accordingly, it is a principal object of the present invention to provide an improved stuffing box assembly.

Another object of the present invention is to provide such an assembly which provides ready access to the adjusting means for the packing gland by eliminating the need for lateral support structures for ancillary apparatus such as a valve actuator.

Still another object of the present invention is to provide such as assembly which minimizes the amount of material or structure which must be employed in the neck area of the housing.

A further object of the present invention is to provide such an assembly which eliminates adjusting nuts, utilizing only adjusting screws, the latter remaining longitudinally fixed during adjustment of the gland.

Another object of the present invention is to provide such an assembly in which the housing has a lateral slot or hole through which the gland flange extends.

Yet a further object of the present invention is to provide such an apparatus in which both the gland flange and a cooperative housing flange are longitudinally spaced from the main body portion of the housing, with the engagement portion of the gland adjusting means being located in the space thus provided.

Still other objects, features, and advantages of the present invention will be made apparent by the following detailed description of preferred embodiments, the drawings, and the claims.

FIG. 1 is a partial perspective view of the stuffing box area of a valve assembly.

FIG. 2 is a longitudinal cross-sectional view of the apparatus of FIG. 1.

FIG. 3 is a transverse cross section taken along the line 3--3 of FIG. 2 and looking in the direction of the arrows.

FIG. 4 is a transverse cross section taken along the line 4--4 in FIG. 2 and looking in the direction of the arrows.

FIG. 5 is a detailed view, similar to the upper right portion of FIG. 2, showing a modification of the invention.

Referring first to FIG. 1 there is shown the upper portion of a valve assembly, more specifically a butterfly valve. The valve assembly includes a housing 10 comprising a generally annular main body portion 12 defining a fluid flowway 14. Housing 10 also includes a generally tubular neck portion 16 formed integrally with main body portion 12. In the normal operating position, neck 16 will extend generally upwardly from main body portion 12, and in any event, the length of neck portion 16 extends generally radially with respect to flowway 14. As used herein, terms such as "radially," "longitudinally," "laterally," etc., unless otherwise indicated, will denote orientation with respect to neck 16.

Referring now to FIGS. 2, 3 and 4 in conjunction with FIG. 1, the valve housing or valve body 10 has a bore 18 extending longitudinally through neck 16 and through the adjacent part of main body portion 12 into communication with flowway 14. In a manner well known in the art, a valve element in the form of a disk (not shown) is rotatably mounted in flowway 14 to open and close the latter. Specifically, the valve element is mounted on a shaft or valve stem 20 which extends outwardly through bore 18 and is rotatably mounted therein. The outer end of valve stem 20 extends beyond housing 10 and has wrench formations 22 thereon for engagement with a valve actuator to be mounted on top of housing 10. Main body 12 of housing 10 also includes integral tabs 24 formed on the upper side of main body portion 12 generally on opposite sides of neck 16. Each tab 24 has a bore 26 therethrough for receipt of a stud or the like used in mounting the valve assembly in a pipeline or the like. Housing 10 further includes housing flange means in the form of a pair of diametrically opposed flanges or ears 28 extending laterally outwardly from neck 16 at a position spaced longitudinally along neck 16 from main body portion 12 of the valve housing. Extending upwardly from the upper side of flanges 28 are a pair of slots 30 each communicating with bore 18 and opening radially outwardly through neck 16 directly above a respective one of the flanges 28. Finally, integrally formed at the upper end of neck 16 is an annular mounting flange 32 on which the valve actuator would be mounted. Flange 32 has a plurality of bores 34 for receiving bolts or the like to secure the valve actuator to the flange. Flange 32 also has a pair of diametrically opposed recesses 36 each continuous with and forming the upper portion of a respective one of the slots 30.

The upper portion of bore 18 is counterbored as shown in FIG. 2 to provide an annular space between valve stem 20 and the surrounding portion of housing 10 to receive a stack of packing rings diagramatically indicated at 38. Rings 38 may be of any conventional type, usually at least partially comprised of an elastomer, and in any event, deformable so that, when compressed longitudinally, they will expand radially and seal tightly between valve stem 20 and housing 10. A rigid support ring 40 rests on the shoulder formed between the large and small diameter portions of bore 18 to support packing rings 38 thereabove. A packing gland has a cylindrical compression portion 40 surrounding valve stem 20 and extending into bore 18 to rest on the upper end of the stack of packing rings 38. Integrally formed with compression portion 40 are a pair of gland flange arms 42 each extending laterally outwardly through a respective one of the slots 30 in the housing. In the longitudinally outermost position, flange arms 42 are received in recesses 36. The fit of compression portion 40 about shaft 20 and within bore 18 is loose enough to permit it to move longitudinally inward, the lower portions of slots 30 (in neck 16) permitting movement of flange arms 42. It can be seen that, if the gland 40, 42 is driven inwardly, i.e., toward the stack of seal rings 38, it will compress the seal rings. Thus, the gland can be used to tighten the seal between the valve stem and housing as desired.

In order to provide for such longitudinal adjustment of gland 40, 42, a pair of adjusting screws 44 are provided. Each of the screws 44 is oriented with its head 44a lowermost and its shank extending upwardly therefrom. As shown, the head 44a of each screw abuts the underside of a respective one of the housing flanges 28, with the shank being rotatably but non-threadedly received in a slot 46 in that flange. Thence, the shank of the screw 44 extends further longitudinally outwardly and is threadedly connected to a respective one of the gland flanges 42. It can be seen that the abutment of the screw heads 44a with the flanges 28 will prevent movement of screws 44 in an upward direction, i.e., away from the stack of seal rings 38. Thus, if screws 44 are engaged by their heads 44a and rotated in the direction which would tend to drive them upwardly, the gland 40, 42 will instead be driven downwardly against the seal rings 38 to tighten their sealing engagement as described above.

It can be seen that the arrangement described above has numerous advantages over prior art stuffing box arrangements, particularly those commonly used on valves. The heads 44a which form the engagement portions of the adjusting screws 44, are disposed in the spaces formed between flanges 28 and tabs 24 and are readily accessible for engagement to adjust the gland 40, 42. This represents a great advantage over prior art arrangements wherein the adjusting nuts were not only disposed close to the actuator, but were also blocked laterally outwardly by the actuator support formations paralleling the valve neck proper. Nevertheless, this advantage is obtained without significantly increasing the amount of material used in the valve neck area, the only valve housing structures specifically provided for the purpose of cooperating with the adjusting system being the two relatively small flanges 28.

Referring now to FIG. 5, there is shown a modification of the invention in which like parts have been given like reference numerals. More specifically, all parts of the structure of FIG. 5 are identical to that of FIGS. 1-4 except for the gland adjusting means. In the structure of FIG. 5, the screw 44 with its integral head 44a has been replaced by a screw 48 having an adjustable nut 50 threadedly connected thereto. One end of screw 48 is fixedly secured to gland flange 42 by a pin 52. From flange 42, screw 48 extends downwardly and is non-threadedly received in an oversized bore 54 in housing flange 28'. Nut 50 is secured to the lower end of screw 48 so that it abuts the underside of flange 28'. Thus, if nut 50 is rotated in the proper direction, screw 48 and gland 40, 42 will be jointly drawn downwardly to compress the seal rings 38. Although both embodiments of the invention achieve the general advantages of providing ready access to the engagement portion (44a or 50) of the gland adjusting means, while reducing the amount of metal which must be provided in the neck area of the valve housing, the embodiment of FIGS. 1-4 may be preferred since it does not require that any portion of the gland adjusting means move downwardly along with the gland, such movement being limited by the upper end of tab 24.

Numerous modifications of the preferred embodiments described above will suggest themselves to those of skill in the art. Accordingly, it is intended that the present invention be limited only by the claims which follow.