Head closure system

Claim 2

A head closure system for a generally cylindrical pressure vessel and a closure head having outwardly extending mating flanges with a plurality of vertically aligned holes therein, comprising studs rotatably disposed in said holes to retain the head on the vessel, each stud having a plurality of separate parallel horizontally extending interrupted threads at its lower portion and also at its upper portion, each hole in the vessel flange having threads therein corresponding to the threads at the lower portion of each stud, said threads being aligned in vertical sections with gaps between sections having a greater angular extent than the angular extent of the thread sections, said stud being rotatable to align the thread sections on the studs with the thread sections in the vessel flange, portable tensioning means adapted for mounting on said closure head for applying tension on each stud to retain the head on the vessel, and said tensioning means having threads therein corresponding to the threads at the upper portion of the stud for attaching the tensioning means to the stud.

Claim 3

The head closure system defined in claim 1, including a rotatable member mounted in the tensioning means and containing the threads corresponding to the threads at the upper portion of the stud; and a device on said tensioning means for turning said rotatable member to selectively align the threads thereon with the stud upper portion threads to thereby permit said tensioning means to selectively elongate said stud.

Claim 4

The head closure system defined in claim 2, WHEREIN the rotatable member comprises a vertically disposed shaft, and including thrust bearing means at the lower end of the shaft supporting the shaft on the upper end of the stud.

Claim 5

The head closure system defined in claim 3, including an extension on the shaft extending below said bearing means and containing the threads corresponding to the threads at the upper portion of the stud.

Claim 6

The head closure system defined in claim 2, including additional means for rotating said stud through a predetermined number of degrees separately from the rotatable member in the tensioning means.

Claim 7

The head closure system defined in claim 5, including locking means for preventing rotation of the stud during rotation of the rotatable member in the tensioning means.

Claim 8

The head closure system defined in claim 4, wherein the tensioning means includes at least one hydraulically actuated piston surrounding the shaft.

Claim 9

The head closure system defined in claim 7, including a member fixed on the shaft for transmitting thrust from the piston to the shaft, and an adjustable member on the stud below the extension on the shaft to which the stud loading is transferred when the hydraulic pressure is removed.

Claim 10

The head closure system defined in claim 8, including mechanical means for actuating the adjustable member.

Claim 11

In a head closure system for a generally cylindrical pressure vessel and a closure head having outwardly extending mating flanges with a plurality of vertically aligned holes therein, in combination, holding studs disposed in said holes to retain the head on the vessel, each stud having a plurality of separate parallel horizontally extending interrupted threads at its upper portion, portable tensioning means for applying tension on each stud to retain the head on the vessel, said tensioning means having threads therein corresponding to the threads at the upper portion of the stud for attaching the tensioning means to the stud, said threads being aligned in vertical sections with gaps between sections having a greater angular extent than the angular extent of the thread sections, a rotatable member mounted in the tensioning means and containing the threads corresponding to the threads at the upper portion of the stud, means for rotating said member to align the thread sections in the member with the thread sections on the stud, a generally cylindrical shroud structure mounted on the head, a circular track supported by the shroud structure, and at least one hoist mechanism movably mounted on the track for handling the portable tensioning means.

Claim 12

In a head closure system for a generally cylindrical pressure vessel and a closure head having outwardly extending mating flanges with a plurality of vertically aligned holes therein, in combination, holding studs disposed in said holes to retain the head on the vessel, each stud having a plurality of separate parallel horizontally extending interrupted threads at its upper portion, portable tensioning means for applying tension on each stud to retain the head on the vessel, said tensioning means having threads therein corresponding to the threads at the upper portion of the stud for attaching the tensioning means to the stud, said threads being aligned in vertical sections with gaps between sections having a greater angular extent than the angular extent of the thread sections, a rotatable member mounted in the tensioning means and containing the threads corresponding to the threads at the upper portion of the stud, means for rotating said member to align the thread sections in the member with the thread sections on the stud, a generally cylindrical shroud structure mounted on the head, a circular track supported by the shroud structure, and at least one hoist mechanism movably mounted on the track for handling the portable tensioning means.

Claim 13

The combination defined in claim 10, including alignment guides attached to the shroud structure for aligning the tensioning means with reference to the studs.

Claim 14

The combination defined in claim 10, wherein the circular track includes an I-beam having a rail secured to its top flange, the hoist mechanism comprises a trolley carriage having a flanged roller riding on the rail, and safety latch means disposed in close proximity to the bottom flange of the I-beam to prevent derailment of the trolley carriage.

Claim 15

The combination defined in claim 12, wherein the latch means includes a shaft rotatably mounted on the trolley carriage and means operable by the shaft into close proximity to the bottom flange of the I-beam.

Claim 16

The combination defined in claim 13, including a handle for rotating the latch shaft, and a spring-biased latch pin for retaining the handle in preselected positions.

Claim 17

A tension load distribution system, comprising a holding member having a hole therein for receiving a tension stud member, said stud member having a plurality of separate parallel horizontally extending interrupted threads thereon, said holding member having threads in the hole corresponding to the threads on the stud member, said threads being aligned in vertical sections with gaps between sections having a greater angular extent than the angular extent of the thread sections, one of said members being rotatable to aLign the thread sections on the stud member with the thread sections in the holding member, stud tensioning means mounted on said holding member for elongating the stud member when the stud member and holding member threads are in alignment, and said stud member having an axially extending hole therein with varying diameters which respectively correspond with said threads mounted on the stud member, thereby to permit the application of equal loading on all stud members threads when the stud member is elongated by said stud elongation means.

Claim 18

A tension load distribution system, comprising a holding member having a hole therein for receiving a tension stud member, said stud member having a plurality of separate parallel horizontally extending interrupted threads thereon, said holding member having threads in the hole corresponding to the threads on the stud member, said threads being aligned in vertical sections with gaps between sections having a greater angular extent than the angular extent of the thread sections, one of said members being rotatable to aLign the thread sections on the stud member with the thread sections in the holding member, stud tensioning means mounted on said holding member for elongating the stud member when the stud member and holding member threads are in alignment, and said stud member having an axially extending hole therein with varying diameters which respectively correspond with said threads mounted on the stud member, thereby to permit the application of equal loading on all stud members threads when the stud member is elongated by said stud elongation means.

Claim 19

The tension load distribution system defined in claim 15, wherein the hole is substantially coextensive with the threads on the stud.

Claim 20

The tension load distribution system defined in claim 15, wherein the diameters become smaller in steps extending from the entrance to the hole.

Claim 21

The tension load distribution system defined in claim 17, wherein the decreasing hole diameter steps provide corresponding stud sections having increasing cross-sectional areas.

Claim 22

The tension load distribution system defined in claim 18, wherein the number of stud sections corresponds to the number of threads on the stud.

Claim 23

The tension load distribution system defined in claim 15, wherein the holding member thread pitch is the quantity (P + Y) where P is the stud member thread pitch and Y is the elongation per pitch under maximum stud load.

Claim 24

The tension load distribution system defined in claim 20, wherein the loading on all threads is substantially equal when maximum load is applied on the stud.