Fluent material handling – with receiver or receiver coacting mea – Filling means with receiver or receiver coacting means – Interlocked discharge means – support and/or coupling
Reexamination Certificate
1999-12-14
2001-03-27
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Filling means with receiver or receiver coacting means
Interlocked discharge means, support and/or coupling
C141S383000, C141S385000
Reexamination Certificate
active
06206059
ABSTRACT:
BACKGROUND OF THE INVENTION
A) Field of the Invention
This present invention relates to an apparatus and method for moving coke from a drum, commonly used in the petroleum industry, and directing this coke into a chute. More specifically this invention pertains to an automated low clearance skirt lifting assembly for vertical vessels such as coke drums. It pertains particularly to an automated extendible assembly used in combination with one or more hydraulically or pneumatically actuated members situated within a telescoping assembly.
B) Background Art
During operation of delayed coking drums for the coking of various heavy hydrocarbon materials in petroleum refining operations, the resulting coke is deposited progressively in the inner walls of the drum and when full, must be periodically removed, usually at 24 hour intervals. A typical apparatus for such coking drums is disclosed by U.S. Pat. No. 4,611,613 to Kaplan. Such coke removal from coking drums is accomplished through an opening in the lower end of a vertically oriented drum, after the bottom head is removed, the skirt is typically raised manually by means of hoisting equipment or automatically by means of single stage hydraulic cylinders. However, because coking drums operate at elevated temperatures, 800-900° F., personnel hazards exist due to exposure of fallout of coke once the head cover is removed. The manual means is hazardous and undesirable. The hydraulically activated means is preferred. However, existing low clearance skirts retrofitted with telescoping cylinders with space limitations have not operated successfully due to volume differential inherent to conventional telescoping cylinders. Single acting cylinders have operated for short periods of time in high clearance applications, but have experienced excessive seal fatigue due to side loading and exposure to the coke dust and corrosive environment. While the prior skirt devices have been found to have serious deficiencies when applied to raising the skirts of coke drums. Such deficiencies have now been advantageously overcome by the present invention.
SUMMARY OF THE INVENTION
This invention provides an automated skirt lifting device assembly, which is adapted to the remote raising and lowering of skirts on a vertically oriented vessel such as a coking drum. The invention includes a circular or multifaceted connector unit which is attached to the upper portion of the skirt, and one or more extendible enclosures, with internally mounted extendible devices that are hydraulically or pneumatically activated.
In one embodiment, for the low clearance application, the extendible device consists of a plurality of short stroke devices mounted with opposing strokes, essentially more than doubling the extension range over the required envelope in the collapsed mode while maintaining staging of the one or more devices due to the commonality of actuating parts and associated surface areas. In the case of the two or more actuating devices, this invention provides a method for equally delivering the actuating force to all units to insure uniform simultaneous extension or retraction of the device.
Desirably the skirt device consists of a tubular or multifaceted reinforcement attached to the top edge of the coker skirt with one or more circular, or multifaceted extendible pair of hollow tubes enclosing a low clearance opposedly acting Siamese cylinder. This device is capable of an extended length that is more than double its collapsed length. The inner tube is slidably-mounted within the outer tube and is attached by means of an arm extension to the skirt reinforcement. The outer tube is firmly mounted to the deck or chute structure. The inner tube is slide activated with respect to the outer tube either hydraulically or pneumatically.
In one preferred embodiment, the hydraulic system employs the use of two or more conventional hydraulic cylinders joined together at the cylinder body in a Siamese fashion with opposed acting extendible rods attached to identical pistons mounted within the identical bore of each cylinder. Hydraulic oil is provided to all cylinders by means of the lower extension rod which is hollow and encompasses two hydraulic tubes and is bored with two inlet ports and respective oil galleries. This methodology permits the raising of the cylinder barrel without moving the hydraulic line from the metering device. The flow is metered in both the supply and return lines by means of a flow divider which insures simultaneous and equal extension or retraction of each cylinder; thereby eliminating binding of the skirt which is inherent to the use of conventional telescoping cylinders. Also this can be a pneumatic system, using air or steam.
To describe the invention in other terms, the skirt section has an upper inlet end which is movable from a lower retracted position to an upper engaged position to receive the coke from the coking drum. There is a plurality of fluid actuators arranged to be in operative engagement with the skirt to move the skirt between its retracted and engaged positions.
In one preferred embodiment, each of the actuators comprises first and second cylinder and piston units, having first and second cylinders, respectively, and first and second piston members, respectively, with each piston member comprising a piston and a piston rod. The first and second cylinders are positioned in side by side relationship and arranged so that the first piston member extends in a downward direction from its related cylinder, and the second piston member extends upwardly from its related second cylinder.
The lower end of the piston rod of the first piston member is connected to a lower base location, and an upper end of the piston rod of the second piston member is connected to the skirt section. Thus, when each of the fluid actuators are extended, an extension of the first piston member from the first cylinder causes the first and second cylinder members to move upwardly, and an extension of the second piston member from the second cylinder moves the upper end of the piston rod of the second piston member upwardly to move the skirt upwardly towards its upper engaged position.
In the hydraulic system of the embodiment described immediately above, there is a first fluid inlet/outlet at the lower end of the first piston rod and a passageway on the first piston rod leading from the first fluid inlet/outlet to a pressure region in an upper part of the first cylinder above the first piston. Thus, fluid from the first inlet/outlet travels upwardly through the passageway of the first piston rod to cause upward movement of the first and second cylinders.
Further, there is a first fluid outlet/inlet at the upper pressure region of the first cylinder, leading to a second pressure region in a lower part of the second cylinder and below the first piston in the second cylinder. The fluid flow through the first inlet/outlet causes fluid to flow upwardly through the passageway in the piston rod of the first piston member into the first piston pressure region, and thence into the second pressure region of the second cylinder so as to cause motion said first and second piston members to extend.
There is a second fluid outlet/inlet at a lower end of the piston rod of the first piston member through which fluid flows from the piston rod of the first piston member during extension of the first piston member. The piston rod of the first piston member has a fluid outflow passageway having an upper opening at the upper end of the first piston member to receive an outflow of fluid from an annular region between the piston rod of the first piston member and the first cylinder.
There is a third fluid inlet/outlet at the lower end of the first cylinder which communicates with the annular region between the first cylinder and the piston rod of the first piston member to receive fluid flow from an annular region that is between the piston rod of the second piston member and the second cylinder. When the first and second pistons are moving toward an extended position, fluid flow fro
Maakad Guy
TerWisscha Richard
Douglas Steven O.
Hughes Robert B.
Hughes & Schacht, P.S.
Huynh Khoa
LandOfFree
Skirt lifting apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Skirt lifting apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Skirt lifting apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2536627