Sealing bolt and method of installing a sealing bolt
11410578 · 2022-08-09
Assignee
Inventors
Cpc classification
F16B31/021
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B33/004
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16B41/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
A sealing bolt includes a seal head adapted to be mounted to the container lid, a seal stud adapted to be mounted to the container body, a pin connecting the seal head to the seal stud, a conductor in a transverse passage in the pin and a resilient member arranged for biasing the pin into a first position in which the conductor is compressed. The pin is movable against biasing by the resilient member into a second position by application to the seal head of a predetermined torque. The sealing bolt also includes a monitoring and detection unit including a transmitter and a detector coupled to respective ends of the conductor, and a processor coupled to the transmitter and the detector operable to determine that the pin has been moved into the second position for a first time when a signal detected by the detector has undergone a predetermined change.
Claims
1. A sealing bolt for sealing a container lid to a container body, said sealing bolt comprising: a seal head adapted to be mounted to said container lid; a seal stud adapted to be mounted to said container body; a pin connecting said seal head to said seal stud, a conductor arranged through a transverse passage in said pin, a resilient member arranged for biasing the pin into a first position in which the conductor is compressed, wherein the pin is movable against the biasing by the resilient member into a second position in which the conductor is uncompressed by application to the seal head of a predetermined torque, and a monitoring and detection unit, the monitoring and detection unit including a transmitter and a detector coupled to respective ends of the conductor, a processor, coupled to the transmitter and the detector, the processor being operable to determine that the pin has been moved into the second position for a first time when the processor determines that a signal from the transmitter detected by the detector has undergone a predetermined change caused by the conductor going from being compressed to being uncompressed.
2. The sealing bolt according to claim 1, wherein the predetermined change comprises a change in detected signal magnitude greater than a first predetermined threshold.
3. The sealing bolt according to claim 1, wherein the predetermined change comprises a transition in detected signal magnitude from below a second predetermined threshold (VL) to above a third predetermined threshold (VU).
4. The sealing bolt according to claim 1, wherein the predetermined change comprises (i) a change in detected signal magnitude or (ii) a transition in detected signal magnitude having a duration less than or equal to a predetermined time threshold.
5. The sealing bolt according to claim 4, wherein the processor is operable to sample the detected signal magnitude at a predetermined frequency to derive sampled signal magnitudes.
6. The sealing bolt according to claim 5, wherein the monitoring and detection unit further comprises non-volatile memory, and wherein the processor is operable to store the sampled signal magnitudes in a log in the non-volatile memory.
7. The sealing bolt according to claim 6, wherein the sampled signal magnitudes are time- and date-stamped in the log in the non-volatile memory.
8. The sealing bolt according to claim 1, wherein the conductor comprises an optical fiber, the transmitter comprises an optical transmitter, and the detector comprises an optical detector.
9. The sealing bolt according to claim 1, wherein the conductor comprises an electrical fiber, the transmitter comprises an electrical transmitter, and the detector comprises an electrical detector.
10. The sealing bolt according to claim 1, wherein the conductor comprises a fluid tube, and the detector comprises a pressure detector or a flow detector.
11. The sealing bolt according to claim 1, wherein the monitoring and detection unit further comprises one or more visual indication elements.
12. The sealing bolt according to claim 11, wherein the processor is operable to illuminate the one or more visual indication elements (i) in a first state, indicating that the pin has not yet been moved out of the first position, or (ii) in a second state, indicating that that the pin has been moved into the second position for the first time.
13. The sealing bolt according to claim 12, wherein (i) in the first state, one of the one or more visual indication elements are illuminated and, in the second state, two or more of the visual indication elements are illuminated, and/or (ii) in the first state, the one or more visual indication elements are illuminated in a first color and, in the second state, the one or more visual indication elements are illuminated in a second color different than the first color.
14. The sealing bolt according to claim 1, wherein the predetermined torque corresponds to a compressive force on the resilient member lying in a range of 700-2500 daN.
15. The sealing bolt according to claim 1, wherein the predetermined torque corresponds to an axial displacement of the pin relative to the seal head lying in a range of 0.5-1.5 mm.
16. A method of installing a sealing bolt, comprising: providing a sealing bolt according to claim 1; transporting the sealing bolt to an installation site at which a container to be sealed is disposed; verifying that the sealing bolt has not been tampered with; and if not installing the sealing bolt on the container; wherein said installing includes applying the predetermined torque to the sealing head of the sealing bolt until the processor determines that the signal detected by the detector has undergone the predetermined change.
17. The method of installing a sealing bolt according to claim 16, wherein the transporting the sealing bolt to an installation site comprises: placing the sealing bolt in a tamper prevention system; transporting the tamper prevention system to the installation site at which the container to be sealed is disposed; verifying that the tamper prevention system has not been tampered with; and if not, removing the sealing bolt from the tamper prevention system.
18. The sealing bolt of claim 14, wherein the range is 700-1500 daN.
19. The sealing bolt of claim 15, wherein the range is 0.7-1.3 mm.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further details and advantages of the present invention will be apparent from the following detailed description of several not limiting embodiments with reference to the attached drawings, wherein:
(2)
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DESCRIPTION OF PREFERRED EMBODIMENTS
(11) The need for a sealing device able to be installed by the operator without the presence of an inspector is of utmost importance and urgency. At least in embodiments, the present invention seeks to provide a sealing system to be applied to nuclear dry storage casks that fulfils one or more of the following goals: to be installed by the operator alone but to be verified later on, during an inspection, by an inspector who has to trust that the seal has not been tampered in the meantime, meaning that the content of the cask is the same as when it was initially sealed; to include an anti-tampering enclosure containing the seal and an electronic monitoring device enabling the package to be shipped by the inspectors to the operator, while trusting that it has not been modified before installation; to include an electronic system connected to a conductor (e.g. optical fiber or electric cable or fluid tube) passing through the seal which detects that the seal has been installed just once; to be used on nuclear dry storage casks for replacing one or more cask bolts, without requiring modification of the cask itself; to include a conductor in the body of the seal that breaks at any attempt of tampering; to allow verification of the identity and integrity of the seal through an ultrasonic inspection; to carry an identity which can be univocally coupled with the container; and to be able to withstand harsh operating conditions.
(12) In the description and drawings, like numerals are used to designate like elements. Unless indicated otherwise, any individual design feature, component or step may be used in combination with any other design features, components or steps disclosed herein.
(13) In implementing the present invention in respect of a sealing bolt (and reader therefor), techniques as set out in EP 0 658 250 may be used, except as described hereinafter.
(14)
(15) The pin 14 may comprise an area of reduced thickness (not shown) in which a rupture of the pin 14 is expected to occur when the seal head 8 is moved relative to the seal stud 10.
(16) As best seen in
(17) During unscrewing of the seal, the seal head 8 freely rotates with respect to the pin 14 until it reaches an abutment, whereafter it then also entrains the seal stud 10 and the pin 14. As the seal head 8 rotates with respect to the pin 14, the fiber optic 30 passing through both is ruptured by Guillotine effect and a portion 30′ of the fiber optic 30 may be left within the pin 14. The rupture of the fiber optic 30 is used to detect the opening of the sealing bolt 2 through the interruption of a signal passing through the fiber optic 30.
(18) The seal head 8 is further provided with an identification element 32, storing a univocal identity of the sealing bolt 2. Such identification element 32 may comprise an ultrasonic identity element or an RFID tag. In the case of an ultrasonic identity element, techniques as set out in EP 1 042 746 may be used in its implementation.
(19) Further in accordance with embodiments of the invention, the sealing bolt 2 has mounted therein a resilient member, in this embodiment a spring washer 36. The inner upper portions 38 of the spring washer 36 engage the shoulder 40 of pin 14, thereby urging pin 14 upwards. As a consequence, transverse passage 24 of pin 14 pushes the fiber optic 30 upwards and compresses it. The fiber optic 30 is thus in a first (compressed) condition prior to installation. Thus,
(20) With regard to spring washer 36, for this a Belleville washer is suitably used. Belleville washers allow for having a very high force in a small space and, even when completely crushed, one cannot exceed the elastic limit. They may be put in series or in parallel if one wishes to increase the stroke or the force.
(21) The specific washer used in the present embodiment is indicated in the highlighted column of
(22) In the present embodiment, a stress or force of 775 daN is obtained by compressing 1 mm. In addition, to obtain higher forces, two or three of the washers 36 may be placed parallel or in series to optimize the desired force and displacement required for pinching and releasing the fiber optic 30 completely.
(23) A predetermined torque must be applied to seal head 8 in order to counteract the force of spring washer 36, to bring the two lateral passages 26, 28, back into alignment with the transverse passage 24, and thus bring fiber optic 30 back into a fully straight condition. Concerning the association torque/force, this depends on several parameters such as lubrication of the thread of the bolt. For the present purposes, what is important is to generate sufficient force so as to not be able to block the mechanism with something microscopic that could be inserted by the operator. The use of two washers 36 such as this in series would mean that a force of 1500 daN (1.5 tons) was required to block the mechanism. Moreover, even if the force generated in the bolt tightening torque is greater than the maximum force washers, such a washer will stop but will not be destroyed because it cannot exceed the elastic limit.
(24) In embodiments, the predetermined torque corresponds to a compressive force on the resilient member lying in the range of 700-2500 daN, preferably 700-1500 daN.
(25) In embodiments, predetermined torque corresponds to an axial displacement of the pin relative to the seal head lying in the range of 0.5-1.5 mm, preferably 0.7-1.3 mm. In order to detect first use of the sealing bolt 2, the sealing bolt 2 is provided to the operator in the condition (“first position”) shown in
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(27) The electronic monitoring and detection unit 50 is independently powered, e.g. by battery 52, which may have a life of many months to many years. The electronic monitoring and detection unit 50 includes a microprocessor 54, which receives a clock signal from clock 56. The microprocessor 54 may derive real-time date and/or time from clock 56, or may obtain such data continuously from a real-time clock (not-shown), provided within electronic monitoring and detection unit 50; and the real-time date and/or time may be used for time-stamping of data, as discussed below.
(28) Microprocessor 54 is also coupled to non-volatile memory (NVM) 58 which stores control software 60 (e.g. hardwired or firmware) for execution by microprocessor 54 for controlling the electronic monitoring and detection unit 50.
(29) The electronic monitoring and detection unit 50 may further include a short-range communications interface 62 (e.g. near field communication (NFC), radio-frequency ID (RFID) or Bluetooth®), for conducting short-range communications with nearby devices, i.e. over a distance of a few centimeters to a few meters. The electronic monitoring and detection unit 50 may further include a long-range communications interface 64 (e.g. long-range radio or cellular wireless), for conducting long-range communications with remote devices, i.e. over a distance of a few Km to a few hundreds of Km, such as for remote reporting and maintenance.
(30) Preferably, the electronic monitoring and detection unit 50 includes visual indication elements for indicating a current state or status of monitoring and detection unit 50. In this embodiment, the visual indication elements comprise LEDs 66.
(31) In one embodiment, the electronic monitoring and detection unit 50 includes an optical transmitter 70 coupled to processor 54 by interface 72. Via a suitable connector (not shown), one end 74 of fiber optic 30 (see
(32) In another embodiment, the electronic monitoring and detection unit includes an electrical transmitter and an electrical receiver/detector, both coupled to an electrical cable. The electrical transmitter transmits electrical signals (e.g. constant power/intensity) out through the electrical cable.
(33) In yet another embodiment, the electronic monitoring and detection unit includes a fluid transmitter and a fluid receiver/detector, both coupled to a fluid tube. The electronic monitoring and detection unit monitors the parameters (e.g. pressure or flow) of the fluid in the fluid tube.
(34) In use, the received signals are used by the processor 54 to determine whether and/or when the sealing bolt has been moved into a second position for the first time. In this embodiment, when a sufficient and predetermined torque is applied to seal head 8 of sealing bolt 2 (see
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(37) After the installation, the ultrasonic identity element is read for the final identification of the sealing bolt 2 and the integrity is checked. These readings are made using an ultrasonic reading head.
(38) When the seal is removed, the pin 14 is fixed due to being tightened on the cask (container), the seal head 8 is rotating, which means that the fiber optic 30 will be cut between seal head 8 is and pin, and the integrity element will break due to being coupled in rotation with the pin 14 and welded to the seal head 8.
(39) Thus, the sealing bolt 8 transitions under the required predetermined torque from a first position (
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(41) In one embodiment, processor 54 (
(42) In another embodiment, processor 54 (
(43) In embodiments, the monitoring and detection unit further comprises one or more visual indication elements (LEDs 66).
(44) In embodiments, the processor is operable to illuminate the one or more LEDs 66 (i) in a first state, indicating that the pin has not yet been moved out of the first position, or (ii) in a second state, indicating that that the pin has been moved into the second position for the first time.
(45) In embodiments, (i) in the first state, one of the one or more LEDs 66 are illuminated and, in the second state, two or more of the LEDs 66 are illuminated, and/or (ii) in the first state, the one or more LEDs 66 are illuminated in a first color, e.g. red, and, in the second state, the one or more LEDs 66 are illuminated in a second color, e.g. green.
(46) Referring to
(47) In one embodiment, processor 54 (
(48) In one embodiment, processor 54 (
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(50) The sealing bolt 2 may be the same as that described hereinbefore with reference to
(51) As discussed above with reference to
(52) Bag 92 includes a port 94 for engagement with an apparatus (not shown) for applying a vacuum, in use, to the interior of the bag 92. The port 94 is sealable (i.e. during application of the vacuum). For example, sealing may be accomplished by thermal welding of end cap 96 of port 94.
(53)
(54) Referring once again to
(55) Under the control of software in NVM 58, processor 54 is operable to determine when a (predetermined) change in pressure within the bag occurs, or rapidly occurs, i.e. from very low to atmospheric pressure.
(56) The predetermined change may comprise a change in the sensed magnitude of the pressure greater than a first predetermined threshold. Alternatively, the predetermined change comprises a transition in the sensed magnitude of the pressure from below a second predetermined threshold (P.sub.L) to above a third predetermined threshold (P.sub.U).
(57) In embodiments, the predetermined change comprises (i) the change in the sensed magnitude of the pressure or (ii) the transition in the sensed magnitude of the pressure, respectively, having a duration less than or equal to a predetermined time threshold.
(58) The processor 54 may be operable to sample the sensed magnitude of the pressure at a predetermined frequency to derive sampled pressure magnitudes. The processor 54 may be operable to store the sampled pressure magnitudes in the log 61 log in the non-volatile memory 58. The sampled pressure magnitudes may be time- and date-stamped in the log in the non-volatile memory.
(59) In embodiments, the processor is operable to illuminate the one or more LEDs 66 (i) in a first state, indicating that the enclosure has not been opened since sealing of the evacuation port under vacuum, or (ii) in a second state, indicating that that the enclosure has been opened since sealing of the evacuation port under vacuum. For example, (i) in the first state, one of the one or more LEDs 66 are illuminated and, in the second state, two or more of the LEDs 66 are illuminated, and/or (ii) in the first state, the one or more LEDs 66 are illuminated in a first color, e.g. red, and, in the second state, the one or more LEDs 66 are illuminated in a second color, e.g. green.
(60) In use, a method of installing a sealing bolt may comprise first providing or obtaining (i.e. by the inspector) a tamper prevention system as described above.
(61) Optionally, the inspector undertakes verifying that the bag 92 of the a tamper prevention system has not been opened since sealing of the evacuation port 94 under vacuum.
(62) Next, the tamper prevention system is transported (e.g. at the instigation of the inspector) to an installation site at which a container to be sealed is disposed.
(63) Then, once received by the operator, the operator undertakes verifying that the bag 92 has not been opened since sealing of the evacuation port under vacuum. This may involve, e.g., visual inspection of the state indicated by the LEDs 66 illuminated on the monitoring and detection unit 50, or verification by communication with the monitoring and detection unit 50 via short-range communications interface 56, e.g. via NFC.
(64) If the state of the LEDs 66 (e.g. red) indicates that the bag 92 has been opened since evacuation, the sealing bolt 8 it contains is not installed and is discarded.
(65) If, on the other hand, the state of the LEDs 66 (e.g. green) indicates that the bag 92 has not been opened since evacuation, the sealing bolt 8 it contains is removed from the bag 92.
(66) Then, the sealing bolt 8 is installed in the appropriate container.
(67) While embodiments have been described by reference to embodiments of survey devices having various components in their respective implementations, it will be appreciated that other embodiments make use of other combinations and permutations of these and other components.
(68) It should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim.
(69) Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art.
(70) In the claims below and the description herein, any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements/features that follow, but not excluding others.
(71) Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit and scope of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention.
(72) TABLE-US-00001 Legend: 2 sealing bolt 56 clock 4 container lid 58 NVM 6 container body 60 control software 8 seal head 61 log 10 seal stud 62 short-range communications 12 borehole interface 14 pin 64 long-range communications 16 header plate interface 18 area of reduced thickness 66 LEDs 24 transverse passage 68 2.sup.nd end of fiber optic 26 first lateral passage 70 optical transmitter 28 second lateral passage 72 interface 30 conductor (fiber optic) 74 1.sup.st end of fiber optic 32 identification element 76 optical detector 36 spring washer 78 ADC 38 corner portion 80 pressure sensor 40 shoulder 82 ADC 50 monitoring and 90 tamper prevention system detection unit 92 bag 52 battery 94 evacuation port 54 processor 96 end cap