BACKGROUND OF THE INVENTION
1. Field of the Invention
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The present invention relates to the controlling of pressure in a pressure vessel with a valving arrangement that includes multiple rupture disks, wherein if one rupture disk ruptures, a second disk is automatically switched on line to protect the vessel. More particularly, the present invention relates to an improved method and apparatus wherein a switchover valve arrangement is provided with a pressure vessel, the switchover valve arrangement having a pair of branch or secondary flow channels, each closed to flow with a rupture disk. Even more particularly, the present invention relates to an improved method and apparatus for controlling pressure in a pressure vessel wherein a specially configured switchover valve is used in combination with two rupture disks, one or both of the rupture disks being equipped with a sensor so that when a first disk opens due to an over pressure situation the sensor activates a controller that then automatically closes the secondary flow channel having the first, now ruptured disk and opens the secondary flow channel that contains the second rupture disk.
2. General Background of the Invention
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Rupture disks are well known in the art and commercially available. A rupture disk is a device that is placed in a flowline that is in fluid communication with the interior of a pressure vessel. The purpose of the rupture disk is to prevent damage to the pressure vessel in an over pressure situation. Rupture disks come in a variety of sizes, shapes and configurations.
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One of the problems with the rupture of a rupture disk in an over pressure situation of a pressure vessel is that the particular pressure vessel is out of service until the rupture disk can be replaced. This rupture of a disk generates a loss of productivity. Replacement of the rupture disk can involve many hours of work.
BRIEF SUMMARY OF THE INVENTION
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The present invention provides a solution to the problem of excess down time after a rupture disk ruptures to relieve an over pressure situation in a pressure vessel.
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The present invention utilizes a switchover valve arrangement in combination with a pair of rupture disks, wherein one or both of the rupture disks is paired with a nearby sensor.
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When the disk ruptures due to an over pressure situation, the sensor activates a controller. This controller monitors the pressure in the flowline that carries the rupture disk. After the pressure in the system (vessel and valve) falls to a safe level, the controller automatically activates a pneumatic, hydraulic or electric actuator that switches the valve to place the second rupture disk in operating position. The plant, refinery, factory or other entity can thus continue to operate even after a rupture disk ruptures or fails and without having to shut down their operations in order to manually replace the ruptured disk.
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The present invention also enables maintenance or service of one disk while the other disk is on line, without shutting down any operations related to the pressure vessel.
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The present invention thus provides a method of controlling pressure in a pressure vessel having a pressure vessel wall and an interior. The method first provides a flow outlet on the pressure vessel that communicates with the vessel interior to which is affixed a valve housing that is specially configured. The valve housing includes a main channel that attaches to the flow outlet and a pair of branch conduits, each branch conduit providing a secondary flow channel.
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The secondary flow channels are each closed with a rupture disk. A rupture disk burst sensor is placed in one or both of the secondary flow channels, preferably next to a rupture disk. A valving member is provided in the valve housing. The valving member moves between first and second positions, each position closing one of the two secondary flow channels.
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The burst sensor determines if one of the rupture disks has ruptured by sensing pressure in the secondary flow channel that is operational. The method includes moving the valving member to a position that closes the secondary flow channel having the ruptured disk, while simultaneously opening the other secondary flow channel having the second rupture disk.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
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For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
- Figure 1 is a sectional elevation view of the preferred embodiment of the apparatus of the present invention shown in operating position prior to a disk rupture;
- Figure 2 is a partial sectional, elevation view of the preferred embodiment of the apparatus of the present invention;
- Figure 3 is a sectional elevation view of the preferred embodiment of the apparatus of the present invention showing operating position at rupture of a disk;
- Figure 4 is a sectional view of the preferred embodiment of the apparatus of the present invention showing movement of the valving member after rupture of a disk;
- Figure 5 is a sectional exploded view of the preferred embodiment of the apparatus of the present invention showing a partial disassembly for replacement of the ruptured disk;
- Figure 6 is a sectional elevation view of the preferred embodiment of the apparatus of the present invention showing a return of the valving member to the original operating position after replacement of the ruptured disk;
- Figure 7 is a partial sectional elevation view of the preferred embodiment of the apparatus of the present invention; and
- Figure 8 is a partial sectional elevation view of the preferred embodiment of the apparatus of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
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Rupture disk switchover system 10 provides a safety system for preventing over pressure of a pressure vessel 11. The pressure vessel 11 has an outer wall 12 that can include for example a cylindrical section 13 and a pair of dished end sections 14. An opening 15 in pressure vessel 11 extends through outer wall 12. Outlet fitting 17 can be attached to vessel 11 wall 12 at opening 15 as shown in figures 1 and 2.
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An annular flange 18 can be affixed to fitting 17 using welding, or other means known in the art. A second flange 19 is connected to flange 18 with a bolted connection 20 or like connection known in the art. The annular flange 19 can provide an externally threaded section 21 that forms a threaded attachment to the internally threaded section 23 of valve body 22. The outlet fitting 17, flanges 18, 19 and valve body inlet opening 24 define a primary flow channel 16 that communicates with the interior of vessel 11.
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In figures 1-2 and 7-8, the valve body 22 provides an inlet 24, an interior 25 and a pair of outlets 26, 27. The outlets 26, 27 are branch outlets. Each outlet 26, 27 can have an internally threaded section. The first branch outlet 26 provides internally threaded section 28. The second branch outlet 27 provides internally threaded section 29. Piping sections 30, 31 can be attached respectively to the internally threaded sections 28, 29 of the outlets 26, 27 as shown in figures 1-6. The piping sections 30, 31 can be curved as shown.
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Each piping section 30, 31 can be fitted with an annular flange. The piping section 30 provides annular flange 32. The piping section 31 provides annular flange 37. Annular flange 32 is connected (for example, bolted) to annular flange 33. The annular flanges 32, 33 are connected together with bolted connections 20 to secure a rupture disk holder 34 and disk 35 therebetween. The rupture disk holder 34 and flange 33 can be used to secure a rupture disk burst sensor 36 at a position that can be downstream of disk 35 as shown.
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In the preferred embodiment, the rupture disk burst sensor 36 can be positioned in between the rupture disk holder 34 and annular flange 33 as shown. Rupture disk 35 is secured with holder 34 at a position in between piping section 30 and discharge pipe 41. Similarly, a rupture disk 40 is contained in rupture disk holder 39. The rupture disk holder 39 is mounted in between annular flanges 37, 38 which can be secured together with bolted connections 20 as shown in figure 1.
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In an over pressure situation, a rupture disk 35 is designed to prevent damage to the pressure vessel 11 to which it is attached. The apparatus, method and system 10 of the present invention provides rupture disks 35, 40 that can selectively be used to relieve an over pressure situation of pressure vessel 11.
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In figures 1-3, if an over pressure situation develops, rupture disk 35 will rupture until the pressure in primary channel 16 and flowlines 30, 41 gradually lower. Sensor 36 detects this lowering of pressure. When the over pressure situation has been relieved, controller 43 switches valving member 47 to close flowlines 30, 41. This is accomplished by communicating between rupture disk burst sensors 36, 66 and control box 43 using instrumentation lines 44, 67. In the preferred embodiment, the rupture disk burst sensor 36 can, for example, be any Oseco brand sensor, http://oseco.com/pages/products/sensors.html.
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Alternatively, the sensors 36, 66 could be anything that indicates that disk 35 has opened or ruptured such as a magnetic reed switch, pressure sensor, flow sensor, temperature sensor, or the like.
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The control box 43 can be a commercially available controller such as a PLC (programmable logic controller) type unit which is available from GE, GE Fanuc Automation (www.gefanuc.com) and others. Other types of controllers or control boxes could be used. Basically, any controller which can take an input from the sensors 36, 66 and send a signal to the actuator 46 will suffice. Control box 43 communicates via instrumentation line 45 with valve actuator 46. The valve actuator 46 can be a commercially available actuator that can be pneumatic, electric or hydraulic. Instrumentation lines 44, 45, 67 are known and commercially available.
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In figures 7-8, valving member 47 is mounted to valve body 22 with pivot mount 48. Figures 1-2 show an initial position 49 of the valving member 47 wherein it closes secondary flow channel 65 that is the bore inside of pipe section 31. At the same time, the position of the valving member 47 insures that there is an open flow path from the interior of pressure vessel 11, through opening 15 and into primary flow channel 16 that is defined by outlet fitting 17, annular flanges 18, 19 and valve body inlet opening 24.
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With the valving member 47 in the position of figures 1-2, the interior of pressure vessel 11 is also in fluid communication with rupture disk 35. When an over pressure situation occurs, rupture disk 40 is prevented from rupturing because of the closed position of valve 47, namely position 49 in figures 1-2.
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After rupture disk 35 ruptures (as illustrated in figures 3-4), valve member 47 moves to the second position or ending position 50 responsive to operation of valve actuator 46 when sensors 36 and 66 determine that the pressure in secondary flow channel 64 is low enough to prevent damage to rupture disk 40. The valving member 47 in the initial position engages and seats upon valve seat 51. In the ending position, the valving member 47 seats against seat 52 and seals secondary flow channel 64.
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In figures 7-8, the valving member 47 can be attached to and driven by driver arm 53. The driver arm 53 can be connected (for example, a threaded connection) to valve shaft 54. Such a threaded connection 55 can be seen most clearly in figures 7-8.
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Bushings can be provided for securing shaft 54 to valve body 22. These bushings can include upper bushing 56 and lower bushing 57. Worm gear 59 is attached to and rotates with shaft 54. Nut 60 can be used to secure worm gear 59 to shaft 54.
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Disc pin 61 insures proper alignment of valving member 47 relative to driver arm 53 and shaft 54. In figure 8, worm gear 58 is mounted to worm gear shaft 62. The worm gear 58 can be supported with gear bracket 63. Gears 59, 62 (or another gearing arrangement) can assist actuator 46 to rotate shaft 54. Valve actuator 46 can thus interface with and drive worm gear shaft 62. However, any other commercially available actuator 46 can be used to move valving member 47 between the positions shown in figures 1 and 4.
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The following is a list of parts and materials suitable for use in the present invention.
PARTS LIST | Part Number | Description | |
| 10 | rupture disk switchover system |
| 11 | pressure vessel |
| 12 | outer wall |
| 13 | cylindrical section |
| 14 | dished end section |
| 15 | opening |
| 16 | primary flow channel |
| 17 | outlet fitting |
| 18 | annular flange |
| 19 | annular flange |
| 20 | bolted connection |
| 21 | externally threaded neck |
| 22 | valve body |
| 23 | internally threaded section |
| 24 | valve body inlet opening |
| 25 | valve body interior |
| 26 | first branch outlet |
| 27 | second branch outlet |
| 28 | internally threaded section |
| 29 | internally threaded section |
| 30 | first piping section |
| 31 | second piping section |
| 32 | annular flange |
| 33 | annular flange |
| 34 | rupture disk holder |
| 35 | rupture disk |
| 36 | burst disk sensor |
| 37 | annular flange |
| 38 | annular flange |
| 39 | rupture disk holder |
| 40 | rupture disk |
| 41 | discharge pipe |
| 42 | discharge pipe |
| 43 | control box |
| 44 | instrumentation line |
| 45 | instrumentation line |
| 46 | valve actuator |
| 47 | valving member |
| 48 | pivotal mount |
| 49 | initial position |
| 50 | ending position |
| 51 | valve seat |
| 52 | valve seat |
| 53 | driver arm |
| 54 | valve shaft |
| 55 | threaded connection |
| 56 | upper bushing |
| 57 | lower bushing |
| 58 | worm gear |
| 59 | worm gear |
| 60 | nut |
| 61 | disk pin |
| 62 | worm shaft |
| 63 | gear bracket |
| 64 | secondary flow channel |
| 65 | secondary flow channel |
| 66 | pressure sensor |
| 67 | instrumentation line |
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All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.
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Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.
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Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
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Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.
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The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.
