US3592221A

US3592221A - Plate swing valve

Info

Publication number: US3592221A
Authority: US
Inventors: Arthur C Worley; Dominic Cicchino
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1969-12-01
Filing date: 1969-12-01
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13
Also published as: CA925772A; DE2058353B2; DE2058353C3; GB1327254A; DE2058353A1

Abstract

A three-way plate valve for directing a gas stream at high temperature is characterized by an upper inlet port, a pair of adjacent outlet ports and a closure plate for either outlet port pivoted therebetween. The closure plate includes a pair of spaced sealing surfaces for contacting the outlet ports and is attached to a shaft which is journaled in bearings within the valve body. Operation of the valve is effected by an external drive mechanism.

Description

llll 3,592,221

United States Patent [56] Relerences Cited UNITED STATES PATENTS [72] Inventors ArthurCWorky Morrblowu;

Dominic Ckdlino, Rocklway. both of. NJ. 881.072

660 77 33 e i n "we a nH HFA 666 335 999 Ill 356 7O [21] Appl. No.

Filed [22] Dec.l,1969 [45] Patented July 13.1971

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SHEET 1 OF 2 Arthur C. War/ey Dominic Clash/no BY mate AGENT INVENTORS PATENTEB Jun 3 1911 3; 592,221

SHEET 2 BF 2 35 l fX Figure 4 Ar/hur C. War/ey V R Dominic Ciao/lino IN ENTO 8 win M. AGENT lPlLATlE SWING VALVE FIELD OF THE INVENTION This invention is concerned with large aperture plate valves particularly adapted for use in low pressure, high temperature service involving diversion of gas flows having low solids entrainment. The valve finds particular utility in the operation of catalytic cracking furnaces for petroleum hydrocarbons, in which waste gases leaving the catalyst regenerator at a temperature of about 1200 F., containing from 5 to percent of carbon monoxide, is either burned in a waste-heat boiler or is diverted to a stack for discharge to the atmosphere.

Examples of fluid catalytic cracking furnaces and associated waste-heat boilers are illustrated in U.S. Pats. No. Re. 25,220; 2,906,703; 3,158,562; 3,355,380; and 3,362,902; 3,401,124; respectively.

PRIOR ART Prior efforts to develop valves suitable for gas switching or diversion have included slide valves such as shown in U.S. Pat. No. 536,151; butterfly valves such as the valve illustrated in U.S. Pat. No. 1,558,157; and combination folding and butterfly valves as disclosed in U.S. Pat. No. 2,910,284. All of the above valves, while designed for high-temperature service, suffer from excessive leakage past the sealing surfaces or from leakage to the atmosphere and require water-seal tanks to ensure the safety of personnel. Where water-seal tanks are employed, a large amount of space must be allocated for their installation, since very commonly, the gas lines leaving the catalyst regenerators are in the range of 4 to 5 feet in diame- 161'.

More recently, a fluid-expandable disc valve illustrated in copending application Ser. No. 675,083 has been developed which embodies improvements over the prior art but which requires the use of two valves in flue gas service instead of the single valve of the instant invention.

SUMMARY The present invention embodies the design of a plate valve in which closure is effected by plate gravity and differential pressure. It is particularly adapted for use at low pressure and high temperature in flue gas systems requiring switching or bypass arrangements. Flow of gas is switched by rotation of the plate through 180 so as to close a downwardly directed gas path at either extreme, thereby providing absolute interlock. It is economical of piping layout and makes it possible to dispense with water-seal tanks and use only simpleblanking plates between flanges for the protection of personnel when servicing lines or equipment downstream.

GENERAL DESCRIPTION OF DRAWINGS FIG. 1 is a cutaway view of the valve in perspective illustrating the essential features and operative elements.

FIG. 2 is a section through the plate-shaft showing the construction of the shaft bearings.

FIG. 3 is a section through the drive shaft and plate-shaft at a point where they engage each other showing the construction of the loose spline.

FIG. 4 is a section through the spaced closure plates in closed position showing one plate in contact with an outlet nozzle.

FIG. 5 is a section through an outlet port showing the method of support and attachment of the outlet nozzle to the base plate and outer shell.

DETAILED DESCRIPTION OF DRAWINGS Referring to FIG. 1, the valve assembly comprises an upper tubular inlet port I, having an outer shell 2, which may be made of carbon steel and an inner liner 3 which is preferably made from a perforated heat and corrosion resistant alloy such as type 410 stainless steel. The outer shell 2 is connected by means of a flattened truncated conical section 8 through a vertical section 40 to an approximately elliptical baseplate 6. In similar manner, following the contours of the outer shell, the inner liner 3 is connected through liner 33 by means of vertical liner 4] to baseplate liner 30. The space between the outer shell and inner liner is filled with a castable insulation 10 consisting of, for example, alumina and mineral fibers bonded with a calcium aluminate cement. Stiffening ribs 9 disposed about the periphery of the conical section aid in maintaining rigidity and act as supporting members to a structural steel framework (not shown).

Disposed along the major axis of the baseplate 6 are exit ports 4 and 5, having inner liners 7, castable insulation 10 and include outlet nozzles 22. FIG. 5 is a vertical section through exit port 5 showing the method of construction and attachment of the heat and corrosion resistant outlet nozzle 22 to the outer shell of exit port 5. Outer shell 3 is attached as by welding to baseplate 6 and is reinforced by a plurality of gussets 33. Nozzle 22 has its upper edge hard-surfaced with a wear-resistant alloy 23 such as STELLITE No. 6 (a cobaltchromium-tungsten alloy having a Rockwell C hardness of about 45) which is ground and polished to a surface finish of about r.m.s. or less. The lower end of nozzle 22 is attached to outer shell 5 by means of conical sleeve 37 and is further secured by external brackets 35 welded to nozzle 22. Conical sleeves 34 welded to the interior of nozzles 22 covers the edges of liner 7 and helps to smooth the flow of gas into the exit ports. A ring plate 36 protects the perforated liner 30 at its intersection with nozzle 22. The void between outer shell 5 and liner 7 is filled by castable insulation 10. Lining support studs 42 maintain baseplate liner 30 at proper distance and prevent sagging at high temperature.

Along the minor axis of baseplate 6 and midway-between exit ports 4 and 5, a horizontal plate shaft 19 is journaled in bearings 20. Spaced closure plates 11 are attached, as by welding, to shaft 19 by means of moment beams 17 and gussets 13.

FIG. 2 is a section through shaft 19 and illustrates how bearing 20, reinforced by angle brackets 21, is attached to baseplate 6 and protrudes through baseplate liner 30. The bearing consists of a vertically elongated slot permitting vertical movement of the shaft and clearances are sufficient to permit some transverse movement.

Plate shaft 19 terminates in splines comprising parallel flats and is coupled to hollow drive shafts 24 in a socket at point 29. FIG. 3 is a section through 29 showing construction of spline flats 32 and coupling socket 31. The cross section area of the splined shaft ends 31 is equal to or greater than the nominal cross section area of the shaft and is constructed by, for example, welding longitudinal bars to the shaft or by upsetting the ends by forging before machining. Coupling member 311 may be made by plug-welding chordate sections to the interior of the hollow drive shaft 24 and finished by machining. Clearances are provided for a loose fit between the respective flats and the circumferential portions of the coupling. It is preferred that the plane of flats 32 lie in the same plane as closure plates 1 1.

Referring to FIG. 4, the edge of spaced closure plates 11 are shown in closed position resting on hard-surfaced edge 23 of outlet nozzle 22. The plates are constructed by welding circular discs 12 and 113 to a circumferential spacer ring 14 having a plurality of pressure equalization openings 15. Moment beams 17 and gussets 18 are then welded to the plate and ring assembly before stress equalization and annealing. After annealing, contact surfaces 16 are machined to parallelism and a surface finish of about r.m.s. Gussets 18 are bored in line to accommodate shaft 19.

Drive shafts 24 are sealed against leakage by stuffing boxes 23 which are supplied with purge couplings 39, which may be attached to vent lines or may be used for supplying a back pressure of an inert gas such as nitrogen. The external termini of drive shafts 24 are sealed against leakage and are journaled in bearings supported on the structural steel framework.

Pinions 25 attached to drive shafts 24 engage racks 26 which are actuated by pistons 43 in double-acting cylinders 27. The pistons may be operated by a high pressure gaseous medium such as air or by hydraulic fluids. For a typical installation having 4% foot inlet and outlet ports and 5 foot closure plates, a torque of about 500,000 inch/pounds is required to swing the plates. While the hydraulic actuated rack and pinion is the preferred means for rotation of the plates, other means amenable to remote control may be used such as worm gears, pulleys, levers and the like. In order to insure a uniform distribution of the load, the hydraulic pressure actuating the pistons should be piped from a single source.

In operation, the closed nozzle and contacting plate are protected by the upper plate. At the same time the exposed nozzle and upper plate are at the same temperature when switching of gas flow is required. When the plate has been rotated, the clearances provided in the bearings and spline 29 permit the seating surface 16 of the plate to adjust to full contact with the mating surface 23 of the nozzle by means of the weight of plate without the use of any force applied by the pistons.

Having fully and operably described our invention, we claim:

1. A three-way valve for directing a flow of gas comprising:

a. a valve body, said body having an upper inlet port in communication with a pair of substantially coplanar lower exit ports including outlet nozzles;

b. closure means within said valve body attached to a horizontal shaft for sealing said exit ports by force of gravity;

c. bearing means between said exit ports journaling said horizontal shaft;

(1. a pair of oppositely disposed stuffing boxes in communication with said valve body and in coaxial relationship to said horizontal shaft;

e. shaft-rotating means mounted externally to said valve body in coaxial relationship to said stuffing boxes; and

f. shaft-drive means passing through said stuffing boxes connecting said horizontal shaft with said shaft-rotating means.

2. Valve according to claim 1 wherein said valve body comprises an outer shell; an inner liner in spaced relationship to said outer shell; and a castable insulation disposed between said outer shell and said inner liner.

3. Valve according to claim 2 wherein said inner liner is fabricated from a heat and corrosion resistant alloy.

4. Valve according to claim 1 wherein said outlet nozzles include hard-surfaced contact surfaces having a Rockwell C hardness of at least 45.

5. Valve according to claim 1 wherein said closure means comprises a pair of circular plates having inner and outer surfaces; said inner surfaces being connected to a circumferential spacer ring having a plurality of pressure equalization openings and said outer surfaces having seating surfaces located at their peripheries.

6. Valve according to claim 1 wherein said bearing means for said horizontal shaft comprise vertically elongated slots.

7. Valve according to claim 1 wherein shaft-rotating means comprises a double rack engaging a pinion attached to said shaft, said rack actuated by a piston in a hydraulic cylinder.

8. Valve according to claim 1 wherein shaft drive means comprises in combination a loose spline attached to said shaft engaging a socket in a hollow drive shaft.

9. A three-way valve for directing a flow of gas comprising:

a. a valve body, said body having an inlet port in communication with a pair of lower exit ports;

b. closure means within said valve body attached to a horizontal shaft;

. bearing means between said exit ports journaling said horizontal shaft, said bearing means permitting limited floating movement between said horizontal shaft and said valve body to permit self-alignment of said closure means upon said exit ports;

d. at least one stuffing box in said valve body in substantially coaxial relationship to said horizontal shaft; e. shaft-rotating means mounted externally to said valve body in coaxial relationship to said stuffing box; and shaft-drive means passing through said stuffing box, said shaft-drive means including loose coupling means connecting said horizontal shaft with said shaft-rotating means to isolate the floating movement of said horizontal shaft from said stuffing box and said shaft-rotating means. 10. Valve according to claim 9 wherein said exit ports include outlet nozzles having hard-surfaced contact surfaces having a Rockwell C hardness of about 45.

11. Valve according to claim 9 wherein said bearing means for said horizontal shaft comprise vertically elongated slots.

12. Valve according to claim 9 wherein said shaft-drive means comprises in combination a loose spline attached to said shaft engaging a socket in a hollow drive shaft.

Claims

1. A three-way valve for directing a flow of gas comprising: a. a valve body, said body having an upper inlet port in communication with a pair of substantially coplanar lower exit ports including outlet nozzles; b. closure means within said valve body attached to a horizontal shaft for sealing said exit ports by force of gravity; c. bearing means between said exit ports journaling said horizontal shaft; d. a pair of oppositely disposed stuffing boxes in communication with said valve body and in coaxial relationship to said horizontal shaft; e. shaft-rotating means mounted externally to said valve body in coaxial relationship to said stuffing boxes; and f. shaft-drive means passing through said stuffing boxes connecting said horizontal shaft with said shaft-rotating means.

9. A three-way valve for directing a flow of gas comprising: a. a valve body, said body having an inlet port in communication with a pair of lower exit ports; b. closure means within said valve body attached to a horizontal shaft; c. bearing means between said exit ports journaling said horizontal shaft, said bearing means permitting limited floating movement between said horizontal shaft and said valve body to permit self-alignment of said closure means upon said exit ports; d. at least one stuffing box in said valve body in substantially coaxial relationship to said horizontal shaft; e. shaft-rotating means mounted externally to said valve body in coaxial relationship to said stuffing box; and f. shaft-drive means passing through said stuffing box, said shaft-drive means including loose coupling means connecting said horizontal shaft with said shaft-rotating means to isolate the floating movement of said horizontal shaft from said stuffing box and said shaft-rotating means.

10. Valve according to claim 9 wherein said exit ports include outlet nozzles having hard-surfaced contact surfaces having a Rockwell C hardness of about 45.