Rotary Valve

The present invention relates generally to apparatus for controlling the flow of material. In one aspect the invention relates to an improved valve for controlling the flow of material therethrough. In another aspect the invention relates to a feeder for controlling the flow of material therethrough. A more specific aspect of the invention relates to the feeding of particulate catalyst to a catalytic reactor system.

The apparatus of the present invention is an improvement over the valve or feeder mechanisms disclosed in U.S. Pat. Nos. 3,219,208 and 3,139,996. Particulate catalyst, such as chromium oxide deposited on silica or silica-alumina, a relatively abrasive, and it has been found that feeder mechanisms for such catalyst are subject to undesirable wear between the rotary valve plug or rotor and the valve body in which the valve plug or rotor is carried. Such wear can cause both leakage of catalyst into the valve chamber through spaces worn between the valve plug or rotor and the valve body and increased operating torque required to rotate the valve plug or rotor relative to the valve body. In feeder mechanisms employing a tapered valve plug which is spring-biased into slidable sealing engagement with a corresponding tapered surface in the valve body, it has been found that the spring-biasing mechanism can become fouled or otherwise adversely affected by the catalyst which leaks into the valve chamber and contacts the spring-biasing mechanism.

The present invention contemplates a valve for controlling the passage of material therethrough. The valve comprises a valve body defining a valve chamber having a frustoconically shaped bearing surface and having an inlet port and an outlet port, with each of the ports communicating between the valve chamber and the exterior of the valve body. A valve member having a frustoconically shaped outer surface and first and second opposite ends is disposed within the valve chamber and is closely received within the valve chamber in slidable sealing engagement with the bearing surface. The valve is further provided with drive means drivingly secured to the valve member for rotating the valve member about its longitudinal axis within the valve chamber. Force is applied to the second opposite end of the valve member by biasing means carried by the valve body to urge the valve member into slidable sealing engagement with the bearing surface of the valve chamber. The valve body is further provided with passage means in the valve body communicating between the valve chamber and the exterior of the valve body via the biasing means. The valve additionally includes means in fluid flow communication between the passage means and a source of fluid whereby fluid from the source flows through the passage means via the biasing means into the valve chamber so as to prevent the entrance of foreign matter into the biasing means from the valve chamber.

Accordingly, it is an object of the present invention to provide apparatus which overcomes the deficiencies of previous feeder mechanisms.

Another object of the invention is to provide a valve structure which overcomes the problem of material leakage between the valve member and the valve body.

Yet another object of the invention is to provide a valve structure suitable for controlling the feeding of particulate material.

Still another object of the invention is to provide a valve structure wherein torque required to rotate the valve member relative to the valve body is minimized.

Another object of the invention is to provide a valve structure suitable for controlling the feeding of abrasive particulate material which minimizes abrasive wear between the valve member and the valve body.

Yet another object of the invention is to provide a valve structure which is simple and economical in construction and operation.

Other objects, aspects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical cross-sectional view taken along the longitudinal center line of a feeder valve structure constructed in accordance with the present invention; and

FIG. 2 is an enlarged cross-sectional view of the valve member biasing assembly of the valve structure of FIG. 1.

Referring now to the drawing, apparatus for controlling the flow of material therethrough constructed in accordance with the present invention is illustrated therein and is generally designated by the reference character 10. The apparatus 10 comprises a valve body assembly 12, an end flange assembly or cap 14, a valve member assembly 16, a packing and bearing gland and flange assembly 18, a drive shaft assembly 20, and a valve member biasing assembly 22.

The valve body assembly comprises a valve body member 24 having a longitudinal passage 26 extending therethrough and communicating with opposite end faces 28 and 30 on the valve member 24. The valve body assembly further includes a wear liner or insert 32 closely received within the longitudinal passage 26. The wear liner 32 is provided with a tapered or frustoconically shaped longitudinal inner surface which converges toward the end face 30 of the valve body member 24. The valve body member 24 is provided with an inlet port 34 and an outlet port 36 which are in registration with corresponding inlet and outlet ports 38 and 40, respectively, formed in the wear liner 32.

The end flange assembly 14 is secured to the end face 28 of the valve body member 24 by suitable means such as threaded studs 42 and threaded nuts 44. A suitable seal is provided between the end flange assembly 14 and the valve body member 24 by means of an annular seal 46, such as an O-ring, carried in a corresponding annular groove 48 in the valve body member 24. The end flange assembly 14 is provided with a longitudinal passage 50 extending therethrough, which longitudinal passage is preferably coaxially aligned with the axis of the longitudinal passage 26 and the axis of the frustoconically shaped inner surface of the wear liner 32 of the valve body assembly 12. The longitudinal passage 50 is internally threaded thus providing means for mounting the valve member biasing assembly 22 therein as well as providing means for connecting the longitudinal passage in fluid flow communication with a suitable conduit 52 which is in turn connected to a source of suitable fluid, preferably a liquid lubricant such as mineral oil or some other suitable liquid hydrocarbon.

The packing and bearing gland end flange assembly 18 is secured to the opposite end face 30 of the valve body member 24 by suitable means such as threaded studs 42 and threaded nuts 44. A suitable fluid-tight seal is provided between the end flange assembly 18 and the valve body member 24 by means of a suitable annular seal 54, such as an O-ring, which annular seal is carried in a corresponding annular groove 56 in the valve body member 24. The end flange assembly 18 is provided with a pin 58 which extends outwardly therefrom into the longitudinal passage 26 of the valve body member 24 and is received in a corresponding recess 60 in the wear liner 32 to prevent the wear liner 32 from rotating within the longitudinal passage 26 and thereby maintain registration between the inlet and outlet ports of the wear liner and the valve body member 24. The end flange assembly 18 is provided with a longitudinal passage 62 extending the full length thereof and coaxially aligned with the longitudinal passages 26 and 50 of the valve body member 24 and the end flange assembly 14. The end flange assembly 18 is further provided with a bearing end cap 64 which is secured to the outer end of the end flange assembly 18 by suitable means such as threaded cap screws 66. The bearing end cap 64 provides means for retaining the drive shaft assembly 20 within the longitudinal passage 62 of the end flange assembly 18. The end flange assembly 18 is suitably provided with a lubricating fitting 68 which provides means for applying lubricant to the bearings of the drive shaft assembly 20 within the longitudinal passage 62.

The drive shaft assembly 20 comprises a drive shaft 68 journaled within the longitudinal passage 62 by means of a pair of ball bearings 70 and 72, which bearings are separated by a cylindrical bearing spacer 74. The inner end portion of the drive shaft 68 is drivingly secured to the valve member assembly 16 by means of a suitable coupling 76, such as an Oldham type coupling. A rotating seal is provided between the inner end portion of the drive shaft 68 by means of a suitable packing assembly 78. The packing assembly 78 comprises a retainer ring 80, a spring-engaging washer 82 and a compression coil spring 84, a male packing adapter 86, three packing rings 88, a female packing ring 90, and a backup ring 92. The outer end portion of the drive shaft 68 is provided with suitable means, such as a key slot 94, for drivingly connecting the drive shaft 68 to suitable drive means, such as an electric drive motor (not shown) which can be actuated by suitable control means (not shown) to rotate the drive shaft through a predetermined amount of rotation at predetermined times.

The packing and bearing gland end flange assembly 18 is preferably provided with a mounting bracket 96 which provide suitable means for supporting the apparatus 10 in any desired operating position.

The valve body assembly 12, end flange assembly 14, end flange assembly 18, and drive shaft assembly 20, assembled as described above, form a housing which defines a valve chamber 98 within which the valve member assembly 16 is disposed. The valve member assembly 16 comprises a tapered valve plug 100 in the form a truncated cone or a frustrum of a cone. This frustoconically shaped valve plug 100 is sized and shaped to be closely received within the frustoconically shaped inner surface of the wear liner 32 in slidable sealing engagement therewith. The valve plug 100 is provided with a transverse bore 102 which extends through and provides a valve port or cavity which provides means for communicating between the inlet and outlet ports 38 and 40 of the wear liner 32. A solid spherical member 104 is disposed within the bore 102 and is free to move therein. The spherical member 104 is retained as a check valve member within the bore 102 by means of a pair of check valve seats 106 and 108 fixedly secured in the opposite ends of the bore 102. The check valve seats provide sealing engagement with the spherical member 104 when engaged by the spherical member 104 with a suitable amount of differential pressure thereacross. When the valve member assembly 16 is rotated by the drive shaft 68, the openings in the valve port or cavity communicating with the tapered outer surface of the valve plug 100 revolve and define an annular path which communicates with the inlet port 38 and the outlet port 40.

The valve member biasing assembly 22, as best shown in FIG. 2, comprises a tubular outer member 110 having external threads 112 extending the full length thereof. A longitudinal passage 114 extends through the full length of the tubular outer member 110 and is characterized by a radially inwardly extending annular shoulder 116 at the first end portion thereof and an internally threaded portion 118 at the second end portion thereof. A generally cylindrical portion 120 extends between the shoulder 116 and the internally threaded portion 118. A plunger 122 having first and second opposite end portions 124 and 126, is positioned within the first end portion of the longitudinal passage 114 with the first end portion 124 of the plunger 122 extending beyond the first end portion of the longitudinal passage, and with the second end portion 126 of the plunger 122 disposed intermediate the annular shoulder 116 and the internally threaded portion 118 of the longitudinal passage 114. The second end portion 126 of the plunger 122 is characterized by a radially outwardly extending circumferential shoulder which is adapted to abuttingly engage the radially inwardly extending annular shoulder 116 of the outer member 110 to retain the plunger 122 therein. The first end portion 124 of the plunger 122 is preferably hemispherically shaped and surface hardened.

The valve member biasing assembly 22 is further provided with an externally threaded member 128 which is threadedly secured within the internally threaded portion 118 of the tubular outer member 110. The threaded member 128 is provided with a longitudinal passage 130 therethrough which preferably includes a hexagonally shaped recess 132 in the outer end portion thereof which provides means for receiving an Allen wrench therein to facilitate threaded engagement between the threaded member 128 and the outer member 110.

A compression coil spring 134 is disposed within the longitudinal passage 114 of the tubular member 110 intermediate the plunger 122 and the externally threaded member 128. The compression coil spring 134 provides constant biasing action urging the plunger 122 to the right as view in FIGS. 1 and 2. The externally threaded member 128 provides means for adjusting the biasing force provided by the compression coil spring 134 through convenient threaded adjustment of the externally threaded member 128 relative to the internally threaded portion 118 of the longitudinal passage 114.

The tubular outer member 110 is preferably provided with a transverse groove 136 formed in the outer end face of the second end portion of the tubular outer member 110 to provide means for receiving a suitable spanner wrench or flat screwdriver blade to adjust and maintain the position of the externally threaded tubular outer member 110 within the internally threaded portion of the longitudinal passage 50 of the end flange assembly 14, as best shown in FIG. 1. As also shown in FIG. 1, an internally threaded nut 138 is threadedly engageable on the external threads 112 of the tubular outer member 110 to secure the tubular outer member 110 to the end flange assembly 14 when suitable threaded adjustment of the tubular outer member 110 relatively to the end flange assembly 114 has been achieved.

It will be seen in FIG. 1 that the first end portion 124 of the plunger 122 abuttingly engages the outer end face of the valve plug 100. It will be understood that when the valve plug 100 is so engaged by the plunger 122 during assembly of the apparatus 10, the plunger is moved to the left, as viewed in FIGS. 1 and 2, relative to the tubular outer member 110 thus further compressing the compression coil spring 134. The constant force provided by the compression coil spring 134 is supplied to the valve plug 100 through the plunger 122 to urge the valve plug 100 to the right, as viewed in FIGS. 1 and 2, and maintain the valve plug 100 in slidable sealing engagement with the tapered wear liner or insert 32 of the valve body assembly 12.

In operation, the apparatus 10 can be advantageously employed in a system for automatically feeding precisely controlled amounts of particulate catalyst to a continuous catalytic reaction. Such a process employing automatic catalyst feeding is disclosed in U.S. Pat. No. 3,219,208, the disclosure of which is incorporated herein by reference. During such operation of the apparatus 10, a suitable lubricating fluid is provided from a suitable fluid source at a suitable pressure via conduit 52 through the longitudinal passage 50 of the end flange assembly 14 and through the longitudinal passage 130 in the threaded member 128 and the longitudinal passage 114 of the tubular outer member 110 of the valve member biasing assembly 22. Such lubricating fluid is provided at a pressure sufficient to overcome the working pressure applied to the valve member assembly 16 so that the lubricating fluid provides lubricating action between the valve plug 100 and the wear liner or insert 32. Suitable lubricating fluids include, but are not limited to, hydrocarbons employed in the polymerization process, e.g., isobutane, isopentane, cyclohexane or mixtures of any two or more thereof, or a non-poisonous lubricating oil, e.g. pump seal mineral oil, to both prevent catalyst entry into the valve member biasing assembly 22 and to reduce friction and abrasive wear between the valve plug 100 and wear liner or insert 32 to thus substantially reduce the required valve operating torque and greatly prolong the operating life of the apparatus 10. A suitable rate of introduction of mineral oil has been found to be about three drops of mineral oil per minute. It will be understood that the lubricating fluid will pass from the longitudinal passage 114 of the tubular outer member 110 into the valve chamber 98 via the annular clearance between the plunger 122 and the tubular outer member 110, which annular clearance is sufficient for this purpose.

While the apparatus 10 is advantageously employable for the automatic control of the feeding of catalyst to a catalytic reaction, it will be understood that the apparatus structure herein disclosed can also be advantageously employed in the construction of tapered plug valves used in other applications. A significant advantage provided by the apparatus 10 is its capacity to maintain a constant, low-friction sliding sealing engagement between the tapered valve plug and the corresponding tapered wear liner which is extremely advantageous in the handling of both liquids and particulate solids, especially when such liquids or particulate solids are particularly abrasive. Under certain circumstances it may be desirable to provide a longitudinal passage 140 in the valve plug 100 communicating between the opposite end faces thereof. The passage 140 provides means for equalizing the pressure of the lubricating fluid across the valve plug 100 and facilitating lubrication of the valve plug 100 and the packing assembly 78. More than one such passage 140 can be employed if desired.

From the foregoing detailed description of the apparatus of the present invention, it will be seen that the apparatus effectively overcomes the deficiencies of similar prior art devices and provides significant advantages thereover. It will be further understood that the present invention can be advantageously employed in feeding the catalysts disclosed in U.S. Pat. No. 4,325,837, the disclosure of which is incorporated herein by reference. Changes may be made in the combination and arrangement of parts or elements as heretofore set forth in the specification and shown in the drawings without departing from the spirit and scope of the invention as defined in the following claims.