1. Field of the Invention
The present invention relates generally to valves for controlling the flow of fluids including liquids and gases and concerns swing check valves. More particularly, the present invention concerns a top entry swing check valve having a valve body defining an internal seat recess and having one or more seat retaining pins that are fixed to a removable bonnet defining a removable closure for the valve body. The seat retaining pins function to secure a check valve seat within a seat recess of the valve body. A bonnet orienting pin is employed to ensure proper positioning of the bonnet member relative to the valve body and also ensuring proper positioning of the seat retaining pins relative to the seat member. The present invention also concerns a alternative swing check valve construction that effectives lends itself to check valve mechanisms having a pivotally supported member carrying an annular sealing element which establishes sealing engagement with an annular sealing surface within the valve body.
2. Description of the Prior Art
A wide variety of swing check valves, also referred to as clapper valves, have been developed over the years. For the most part swing check valves are of typically simple character, having a valve body that is connected within a flow line that is subject to flow reversal and having a check valve element or clapper that is pivotally mounted within the valve body for pivotal movement to an open position permitting flow through the flow passages of a valve body and a closed position where the check valve element establishes sealing with a seat surface defined within the valve body or a seat member that is retained within a seat recess within the valve body. Many different varieties of swing check valves have been developed and used for many years.
In most cases the valve bodies of swing check valves must be removed from the flow line in the event repair or replacement is needed. Rather than requiring the flow line to be shut down for an extended period of time, in many cases a defective valve is simply removed from the flow line and is replaced with a serviceable valve. This requires the maintenance of an inventory of serviceable valves and adds significant cost to the processes that require check valve control. Valve removal and replacement operations typically require considerable time and thus significant labor costs which in many cases can be avoided. It is desirable therefore to provide swing check valves that have the capability of being repaired while remaining in the flow line, thus minimizing the inventory and labor requirements for valve maintenance.
A number of top entry, in-line repairable type swing check valves have also been developed for the reasons mentioned above. In many cases these valves are threaded into the seat recesses so that they cannot become inadvertently separated from the valve body as shown by U.S. Pat. No. 3,955,592. However, since threaded seats and seat recesses add somewhat to the complexity and cost of manufacturing a swing check valve mechanism, and since threaded valve seats are often very difficult to remove from their seat recesses, it is desirable to provide swing check valves having replaceable, non-threaded types of seats that are simply positioned within the seat recesses. In such case it is necessary to provide some suitable means for seat retention so that the seat cannot be inadvertently separated from its seat recess by turbulence or other conditions of fluid flow through the valve.
To prevent non-threaded seats from being displaced or fall from the internal valve seats certain seat retainer devices have been provided in the past, as shown by U.S. Pat. No. 4,246,928. In this case retainer pins 70 are received within an annular groove of the valve seat and serve to provide for positive retention of the valve seat, and yet permit its limited movement within the valve seat recess.
U.S. Pat. No. 5,056,548 discloses a swing check valve mechanism having a seat that is retained within a seat recess by retainer pins 71 and 73 which extend through passages 47 and 49 of the valve body structure and provide ends that are received adjacent an annular seat retainer flange 55. In this case it is noted that the retainer pins are retained in position by an interior annular surface 31 that defines the lower end surface of an annular collar 30 projecting from the bonnet member. For seat replacement, the retainer pins must be individually removed from their passages, after the bonnet has been removed, to permit extraction of the annular seat from its seat recess. It is quite obvious from the disclosure of the '548 patent that fouling by the corrosive effects of the fluid being handled can cause the seat retainer pins to be essentially chemically welded, seized or frozen in place. When such conditions exist it can be extremely difficult or impossible to remove the seat retainer pins from their seat retaining positions. While the valve mechanism is designed for in-line repair, if the seat retainer pins cannot be removed under field repair conditions, it may be necessary to remove the valve body from the flow line and transport it to a repair facility. This would require undesired labor costs and cause significant down time of the flow line, thus detracting from the intended use and commercial feasibility of the swing check valve product.
It is a principle feature of the present invention to provide a novel swing check valve mechanism that employs one or more seat retainer pins for retaining a valve seat within a seat recess of the valve body and ensures removal of the seat retainer pins as components of the bonnet closure of the valve.
It is another feature of the present invention to provide a novel swing check valve mechanism that employs a bonnet alignment pin that is fixed to the valve body at the bonnet opening and is received by an alignment pin receptacle of the bonnet closure, thus providing for efficient positioning of the bonnet and the pivotally movable swing check member as the bonnet closure is assembled to the valve body.
Briefly, a top entry in-line repairable swing check valve mechanism that embodies the principles of the present invention is a unidirectional check valve that has a valve body that is adapted for connection within a flow line and defines a valve chamber and flow passages that communicate the valve chamber with the flow line. Cylindrical seat surfaces and annular planar shoulder surfaces within the valve body define a valve seat recess within which is contained an annular seat assembly having a seat recess seal for establishing sealing between the seat assembly and valve body. The seat assembly also carries an annular face seal member which establishes sealing with a swing check member in its closed position to provide for flow responsive valve shut-off in the event flow reversal should occur. The seat assembly includes an annular seat retainer flange that engages an annular shoulder within the valve body when the seat assembly has been inserted to its full extent within the seat recess.
The valve body defines an access opening of sufficiently large internal dimension that the seat assembly and swing check member can be inserted into or removed from the valve chamber via the access opening. A bonnet member is releasably retained in sealed engagement with the valve body and forms a closure for the access opening. Seat retainer pins are fixed to the bonnet member and extend into over-size holes or passages that are defined in an internal swing check member support structure that is an integral part of the valve body. When the bonnet member is in place, inner ends of the seat retainer pins are positioned immediately adjacent to or in contact with the annular seat retainer flange of the seat assembly and prevents the seat assembly from being moved out of its seat recess.
The bonnet member also defines a bonnet alignment hole that receives a bonnet alignment pin that is fixed to and projects upwardly from the valve body. The bonnet alignment hole is also over-size in relation to the dimension of the alignment pin to facilitate ease of bonnet assembly. The bonnet alignment pin ensures that the bonnet is properly aligned with respect to the valve body so that the seat retainer pins will be easily inserted through the seat retainer holes of the valve body and into seat retaining position with respect to the seat retainer flange of the valve seat assembly.
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.
It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Referring now to the drawings and first to
With reference to
An annular valve seat assembly shown generally at 38, best shown in FIGS. 8,9 and 10, is located within the circular seat recess 28 and has a metal seat ring structure 39 having an annular seat recess seal member 40 that is retained within an annular seal groove 41 and establishes sealing with the cylindrical surface 30. The annular valve seat member 38 defines an annular seat retainer flange 42 which is of greater dimension as compared with the dimension of the cylindrical surface 30 and is disposed for stopping engagement with the annular shoulder 36 as is evident in
As is evident in
A swing check member or clapper shown generally at 70, which is shown by the exploded elevation view of
A support arm 84 extends upwardly from the valve plate 72 and may be integral with or fixed to the valve plate in any suitable fashion. An upper portion 86 of the support arm extends upwardly and laterally from the valve plate and supports a pair of opposed pivot shaft members 88 and 90. The pivot shaft members 88 and 90 are of generally cylindrical configuration and define external cylindrical surfaces 92 and 94 about which are received bushing members 96 and 98 that are best shown in
When the swing check member or clapper 70 is installed for pressure responsive pivotal movement within the valve chamber 26 the bushing members 96 and 98 will be in contact with the angulated groove bottom surface 64. Because of the taper of the groove bottom surface, the bushing members will have a tendency to move rearwardly or toward the right as shown in
In the case of top entry in-line repairable swing check valves it is necessary that the valve seats be rather easily removable so as to minimize the labor that is required for their removal and replacement. It is also appropriate that the valve be designed for field repair via the use of simple, commercially available tools. Often the fluid being controlled by a valve contains corrosive constituents that causes the seats to become seized within their seat recesses. Threaded valve seats are particularly difficult to remove and replace because they must be rotated for removal. If the valve seat is seized within its seat recess, seat rotation may not be possible. The only logical solutions are to remove the valve from the flow line and transport it to a repair facility or to transport special repair tools to the site of the valve and attempt to repair it in place. It is this undesirable condition for which the present invention has been developed.
In the case of the present invention the valve seat is of simple, generally cylindrical configuration and the valve seat is sealed with respect to a cylindrical internal seat recess wall surface by the seat recess seal member 40. The valve seat is installed simply by pushing it into the seat recess until the annular seat retainer flange 42 of the seat establishes movement limiting contact with the internal annular shoulder 36. To ensure that the valve seat will remain within the seat recess during operating conditions a pair of valve seat retainer pins 100 and 102, shown in FIGS. 1,2 and 7, extend through retainer pin openings or passages 104 and 106 that are defined in the internal swing check member support structure 56, shown in
The valve body 12 defines an upwardly extending annular bonnet connection section 112 defining a bonnet flange opening 114. An upwardly facing bonnet seal surface 116 and an internal bonnet seal groove 118 are defined by the annular bonnet connection section 112. A circular bonnet member 120 is secured to the annular bonnet connection section 112 by means of a plurality of bolt and nut assemblies or threaded stud and nut assemblies 122. A circular bonnet seal member 124 is positioned within the bonnet seal groove 118 and establishes sealing between the annular bonnet connection section 112 and the bonnet member 120. The circular bonnet seal member 124 is also retained in position by an external annular surface 126 that is defined by an annular flange 128 that is integral with and depends from the lower portion of the bonnet member 120. The annular flange 128 also serves as a bearing and pivot shaft retainer
It is desirable to ensure that the seat retainer pins 100 and 102 are relatively easy to remove from their passages 104 and 106 to provide for removal of the valve seat from its seat recess during in-line repair. To facilitate this feature the upper ends of the seat retainer pins are fixed to the bonnet member 120 and depend from the bonnet member through the retainer pin openings 104 and 106 to the seat retaining positions shown in
Since the bonnet retainer pins 100 and 102 are fixed to the bonnet member 120, it is necessary that the bonnet member be properly aligned with the annular bonnet connection section 112 so that the seat retainer pins will be properly oriented with respect to the retainer pin openings 104 and 106. This feature is provided by a bonnet alignment pin 130 that is press-fitted within an alignment pin opening 132 of the annular bonnet connection section 112 so that it projects upwardly therefrom. The bonnet member 120 defines a downwardly facing alignment pin opening 134 that receives the alignment pin only when the bonnet member has been properly positioned relative to the annular bonnet connection section 112. Alternatively, if desired the bonnet alignment pin may be fixed to the bonnet member in any suitable fashion and may project into an opening of the valve body.
The partial sectional view of
Referring to
After the seat assembly 38 and the swing check member 70 and its pivot bushings have been installed, the bonnet member 120 is then installed and secured in sealed assembly with the upwardly extending annular bonnet connection section 112 as explained above. Typically a new bonnet seal member 124 will be installed within the bonnet seal recess 118 to ensure the sealed integrity of the bonnet and valve body connection. When the bonnet member is installed, the bonnet member will be positioned so that the downwardly facing alignment pin opening 134 receives the alignment pin 130. This also causes the seat retainer pins 100 and 102 to be properly aligned with respect to the openings or passages 104 and 106 of the internal swing check member support structure 56. Since the downwardly facing alignment pin opening 134 of the bonnet member and the seat retainer pin openings 104 and 106 are each oversize in comparison with the dimension of the respective pins, assembly of the bonnet member is achieved quite easily. The seat retainer pins, being fixed to the bonnet member will be easily moved into seat retaining position relative to the annular seat retainer flange 42, thereby preventing the seat assembly from inadvertently moving out of its seat recess 28.
With reference to
When a swing check valve embodying the principles of the present invention is in need of in-line repair, such as by replacement of the valve seats, seat seals, swing check member or pivot shaft bushing members, the bonnet member 122 is released from its sealed assembly with the annular bonnet connection section 112 of the valve body by removing the bolts or stud and nut assemblies 122. As the bonnet member 122 is removed the seat retainer pins 100 and 102, being fixed to the bonnet, will be removed along with the bonnet. The bonnet alignment pin, being fixed to the annular bonnet connection section 112, will remain in place. Since the depending bonnet flange will no longer be in place within the valve chamber access opening 114 of the annular bonnet connection section 112, the pivot shaft bushings and the pivot shafts will no longer be restrained thereby. The swing check member and its pivot shaft bushings will be moved upwardly through the valve chamber access opening 114 where they will be inspected and repaired or replaced. Typically, new pivot shaft bushings will be installed on the pivot shaft, if the swing check member 70 is not corroded, eroded or otherwise worn, and a new valve or repaired valve seat assembly will be installed. However, if the metal valve seat ring is in good condition then new seal members may be installed, without any need to replace the metal seat ring component.
Since the valve seat 38 of the present invention is not threaded into the seat recess 28 the seat can be extracted from the seat recess simply by moving it linearly to the left from the position shown in
In view of the foregoing it is evident that the present invention is one well adapted to attain all of the objects and features hereinabove set forth, together with other objects and features which are inherent in the apparatus disclosed herein.
As will be readily apparent to those skilled in the art, the present invention may easily be produced in other specific forms without departing from its spirit or essential characteristics. The present embodiment is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.