Heat exchanger closure assembly, and method of using and installing the same heat exchanger closure assembly

Abstract

To provide improved heat exchanger closure assemblies configured to accommodate varying thermal loads.SOLUTION: The invention provides a heat exchanger assembly including an elongated tubular heat exchanger enclosure defining an interior chamber. A tube sheet is positioned within the interior chamber of the heat exchanger enclosure separating the interior chamber into a shell side and a channel side. The interior portion is configured to removably receive a tube bundle positioned within the shell side of the interior chamber. An annular sleeve member is positioned within the channel side of the interior chamber of the heat exchanger enclosure. An annular elastic torsion member is positioned within the channel side of the interior chamber of the heat exchanger, so that the sleeve member is positioned between the tube sheet and the elastic torsion member. The elastic torsion member has an inner circumference deflectable relative to its outer circumference for torsion of the elastic torsion member.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] This application claims the benefit of priority of U.S. Patent Application No. 62 / 645,662, filed Mar. 20, 2018, which is hereby incorporated by reference in its entirety.

[0002] The disclosed embodiments relate to a heat exchanger closure assembly and a method for using and installing the heat exchanger closure assembly, and more particularly, to a closure system and method for sealing a high-pressure shell and tube type heat exchanger having a removable tube bundle, and more particularly, to a heat exchanger closure assembly configured to accommodate varying heat loads and having a closure plug assembly secured to the channels of the heat exchanger using a lock assembly.

Background Art

[0003] Shell and tube type heat exchangers constitute the majority of unfired heat transfer equipment in chemical plants, refineries, steam plants, and similar facilities. Heat exchangers with removable tube bundles, such as those with U-tubes and floating heads, or heat exchangers with non-removable bundles with fixed tube sheets, are the most common types of shell and tube heat exchangers for current use. In practice, it is usually desirable to have a removable tube bundle to enable the heat exchanger to be removed from the facility periodically, where the tube bundle is removed for cleaning and inspection and reassembled later. Also, it may be desirable to hydrostatically or pneumatically test the shell side of the tubular heat exchanger using a removable tube bundle, as a result of which inspections or examinations of tube joints and tube sheet gaskets can be carried out and leaks can be easily found and repaired. To remove the bundle, a closure must be provided that can be quickly opened with high reliability after long-term operation under varying thermal and pressure loads. The problems associated with disassembly, removal, hydrostatic and pneumatic testing, and reassembly are particularly exacerbated when the tubular heat exchanger is relatively large (with a diameter exceeding 91.4 cm (36 inches)) and is for high-pressure operation exceeding 6.9 MPa (1000 psi). This is because the weight of the required components increases. As a particular type of closure developed for this purpose, there is a "screw plug", also known as the "bleed lock" type of closure, which uses multiple interlocking screw parts to fix the lock ring cover assembly in place. The main advantage of this type of system is that it eliminates the large channel cover flanges and bolting of other conventional high-pressure exchanger designs. There are two general types of screw plug type heat exchangers described in the prior art.In applications where the pressure exceeds 6.9 MPa (1000 psi) on both sides of the tube sheet, and thus only a small pressure difference is experienced by the tube sheet itself, it is possible to provide a fully removable "A-Style" closure, where the bundle can be removed without removing the shell cover. If the pressure difference is excessively large, it may be more convenient to remove the shell cover to access the bundle, and in such cases, a "B-Style" closure can be used.

[0004] Also, the closure assembly used in this type of heat exchanger must have sufficient rigidity to have an internal pressure without significantly moving the closure assembly relative to the channels. The reason is that if the closure assembly is significantly moved relative to the channels, the screw parts used to fix the closure assembly will be partially or completely removed. However, the assembly must also have sufficient flexibility to accommodate the expected thermal loads that occur during operation. The expected thermal loads are either temporal temperature changes that may occur during initial startup or subsequent repairs, or any of the exceptional events that may cause a differential thermal expansion of the internal components relative to the channels during an upset or plant trip. Due to thermal loads that are not properly accommodated in one or more embodiments, the internal components may plastically deform non-uniformly, resulting in the gasket load not being uniformly distributed and ultimately leakage starting to occur in the assembly. In particular, due to the diverse thermal expansion rates or the fact that thin internal components can be heated more rapidly than thick channel materials, closure assemblies with high rigidity are undesirable when they cause plastic deformation of the internal components and thereby dislodge the gasket and cause leakage, or when they cause a greater load on the screw parts of the closure assembly and the channels and thereby the screw parts may deform. In all of the above situations and operating conditions, many different technical solutions have been adopted, and many of these different technical solutions have only partially succeeded because they only solve some of these problems and cause other problems, especially in applications where the temperature, pressure, or size is high.

[0005] In all of these prior art solutions, to fully engage the threads in the lock ring with the threads in the heat exchanger channel, a lock ring - cover assembly (or, "closure plug") with threads has to be rotated multiple times (usually 20 or more times). This leads to special handling considerations. The reason is that the lock ring assembly has to be accurately centered and supported when it is outside the channel and rotated to its final position. In particular, due to the fact that the weight of the closure plug cannot be supported on the threads, to accurately handle the heavy piece of the device (about 9525.4 kg (21,000 lb)), it is necessary to supply a dedicated jig along with the heat exchanger. A variety of jig designs have been developed. In some cases, a cantilever counterweight is used to maintain the balance of the weight of the lock ring. In other cases, the jig is directly attached to the channel.

[0006] However, since this special jig has no other functions and may be used very rarely, the operator who works on the exchanger may be unfamiliar and will completely rely on the instructions provided by the manufacturer. In the worst - case scenario, if the heavy assembly is not accurately fixed to the jig, there is a risk that the factory worker working on the exchanger may get injured. There is also always the risk that the closure plug may jam or that the threads may be damaged during insertion or removal. This is especially true in cases where the closure plug is first inserted into the heat exchanger channel. In a factory turnaround or during repairs, time is of the essence, so the unplanned downtime associated with a jammed closure plug can result in significant economic losses for the factory or refinery.

[0007] The difficulty of handling the lock ring means that it is not desirable to insert or remove the lock ring more than twice during maintenance. When it is necessary to repair the tube or other pressure-maintaining components, in order to check for leaks, a hydrostatic or pneumatic test on the shell side must be carried out with the cover out of position. The initial design used a temporary internal flange when performing a hydro test on the shell side of the heat exchanger, thereby mounting the gasket. In the case of more recent designs, such as the design shown in U.S. Patent No. 4,750,554, a mechanism is provided to apply a load from the internal flange so as to be parallel to the load from the bolts in the inner row. In the case of these more recent designs, the bolts in the inner row located within the external lock ring are used to mount the tube sheet gasket only in the case of a leak. The internal components required to perform this function can be very complex. Also, although this design is well optimized, due to the number and complexity of the parts, the risk of incorrect installation and an increase in manufacturing costs increases. Due to the internal flange coming into contact with the process fluid, the bolts may corrode or may be coated during coke formation and need to be cut or machined. Also, due to the difference in thermal expansion of the internal components, the internal flange assembly may be damaged or deformed, thereby making it difficult to remove and reuse the assembly.

[0008] Thus, the prior art does not address the issues of handling the closure plug during insertion / removal and enabling a pressure test while maintaining a simple design of the internal components.

[0009] While a screw closure plug heat exchanger can meet the applicable design criteria regarding the pressure-resistant part, there are also other components inside the pressure boundary of the device design that can affect the reliability and life cycle cost of this type of device. There is a need for a device that has sufficient rigidity to limit movement under pressure load while avoiding damage to internal components under the expected heat load conditions and providing fail-safe protection for the pressure-resistant structure (threaded part) under extreme heat load conditions.

[0010] Accordingly, there is still an unmet need in the art for a heat exchanger closure assembly configured to accommodate varying heat loads, having a lock ring and a cover that can be easily installed and removed as needed without using a dedicated handling device.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0012] The objectives and advantages of the exemplary embodiments described below are set forth in and will be apparent from the following description. Additional advantages of the exemplary embodiments are specifically set forth in the description and the claims of the present invention and will be realized and obtained from the device, system, and method, as well as from the accompanying drawings.

[0013] For the purpose of achieving these and other advantages, in accordance with the objectives of the illustrated embodiments, in one aspect, a closure system and method for a shell and tube type heat exchanger are described, where the heat exchanger closure assembly is configured to accommodate varying thermal loads and to have a locking ring that is secured to the channels of the heat exchanger using a plurality of interlocked hubs or threads.

[0014] As already mentioned, the following are prominent concerns for the end user of a shell and tube type heat exchanger. Namely, leakage through gaskets that would allow process fluids such as hydrogen / hydrocarbons to escape to the environment; process leakage between the shell side fluid and the tube side fluid; an unexpected overage in maintenance time due to the closure plug becoming immobile during insertion and removal; the complexity of the numerous internal components and dedicated devices required to support the closure plug during insertion or removal.

[0015] According to certain exemplary embodiments presented herein, the methods / systems disclosed herein for opening, closing, and sealing a high-pressure heat exchanger employ a cover and a lock-ring assembly (e.g., a closure plug), where the closure plug is inserted into the heat exchanger channels in a single linear motion and preferably rotated to a locked position in less than one full rotation (e.g., in a swivel of less than 360 degrees). The load-bearing surfaces (e.g., the insertion holes) preferably do not contact until a final rotation is applied to effectively lock the closure plug to the high-pressure heat exchanger. The channels of the high-pressure heat exchanger are preferably machined to have a first set of insertion holes, and the lock ring is machined to have a complementary second set of insertion holes such that when the closure plug is rotated, the first set of insertion holes is releasably engaged with the second set of insertion holes. In certain embodiments, rails are attached adjacent to one or more sets of insertion holes on the lock ring and / or on the channels, thereby providing a raised section along one side, thereby: (i) preventing excessive rotation; (ii) providing a bearing surface for insertion of the lock-ring assembly; and (iii) preventing damage to the load-bearing surfaces.

[0016] In certain exemplary embodiments, the lock ring is machined to have a set of a predetermined number (e.g., eight) of lock-ring insertion holes, and the heat exchanger channels are machined to have a corresponding number of sets of channel insertion holes. It will be readily appreciated by those skilled in the art that the number of sets of corresponding insertion holes can be varied without departing from the aspects of the invention of the present disclosure. In certain exemplary embodiments, the insertion hole profile is a retaining wall shape.

[0017] It should be appreciated that certain advantages of the disclosed embodiments include a closure plug assembly that can be installed in a single linear operation without the need for a dedicated jig or tool. The closure plug assembly is locked in place by a single partial rotation (e.g., a 22.5° rotation of the plug member) only when it is in its fixed position and fully supported by the heat exchanger channels. The risk that the closure plug will become immovable relative to the heat exchanger channels is eliminated. In addition, handling of the plug member is made safer, since it is not necessary to rotate the closure plug relative to the heat exchanger until it is fully supported. Readily available shop equipment such as cranes, bundle pulling trucks, and fork lift trucks can be used to move the closure plug member to its fixed position, thereby eliminating the costs associated with a dedicated jig. Installation is also made safer, since the lock ring assembly / plug does not need to be rotated simultaneously when it is suspended and centered using a counterweight or cantilever, but instead is preferably slid along a specially designed rail that also serves to provide a rotation stop. The rail is sized to support the full weight of the lock ring assembly of the closure plug on the load-bearing surface of the insertion hole.

[0018] According to the disclosed embodiments, insertion and removal of the closure plug assembly can be accomplished more quickly than with designs using prior art threads. The more rapid insertion and removal allows for the use of simplified internal components, particularly by eliminating the need for internal flanges. In certain embodiments, only a partial rotation (e.g., 22.5°) of the closure plug assembly relative to the heat exchanger tubes is required to lock the ring of the closure plug assembly in place, as opposed to the typically more than 20 rotations in prior art designs. As a result, greater flexibility is obtained in selecting the shape of the load-bearing surface of the closure plug than with the conventional 2.54 cm (1 inch) ACME threads used in the prior art.

[0019] In prior art designs and methods, tightening a screw mechanism means that, through friction, the wedge portion is quickly immobilized and plastically deformed slightly as the wedge portion is pushed into the gap. Thus, to achieve full engagement, the threaded portion must advance over a certain linear distance while rotating. Prior art designs typically use an ACME-style threaded portion with a pitch of usually 2.54 cm (1 inch), such that one rotation advances the plug 2.54 cm (1 inch) into the channel. In contrast, the insertion hole design of the specific embodiment shown in the present invention is an interlocking or mating male-female geometry that engages through rotation, for example, in a single plane, which preferably uses an insertion hole shape (e.g., a retaining wall configuration) such that it has a higher stiffness and is more suitable for cases where the force applied to the insertion hole is mainly in one direction. A rail is provided over the insertion hole and configured to accurately center the lock ring of the plug assembly during insertion so that it cannot be rotated excessively. The rail also functions to protect the insertion hole when assembling the closure plug member to the heat exchanger tube.

[0020] Thus, an obvious advantage provided by the shown embodiment is that it may eliminate the need for a dedicated "jig" such as is required to support and center the lock ring while rotating. According to the shown embodiment of the present invention, since the closure plug rotates when the lock ring of the plug is fully inserted into the channel, in this lock ring design, the time required to open and close the heat exchanger for maintenance work is significantly reduced, the need for special equipment / special handling is eliminated, and thus the risk of leakage due to inaccurate installation is reduced. By shortening the opening and closing time, it is also possible to eliminate the internal flange used for the pressure test, thereby significantly reducing the number of components that must be installed / removed to provide access to the tube bundle.

[0021] It should be recognized that the illustrated embodiments of the present invention are directed to a heat exchanger configuration that allows for thermal expansion under thermal loads that change during operation through the use of an elastic torsion member. By accommodating the expected thermal expansion using the elastic torsion member, a sealed state can be maintained over multiple operating cycles without adjusting the compression bolts provided on the closure plug. The expected thermal loads include heating and cooling of components due to low-frequency but foreseeable events such as startup, shutdown, fluctuations in fluid flow rate, and plant trips or sudden stops. In the case of excessive thermal loads that cause thermal expansion of internal components beyond the range contemplated by this design, it is important to protect the insertion holes of the closure assembly from damage, and thus the torsion member is designed and configured to plastically deform beyond a specific range of elastic deflection. When using conventional designs and methods, it should be recognized that it is often necessary to use dedicated assembly procedures to maintain the sealed state of the internal tube sheet gasket, often involving re-tightening the compression bolts during operation. Even when using these procedures, plastic deformation of internal components can occur during operation due to thermal expansion differences. As described above, this is prevented by the present invention.

[0022] According to a specific embodiment shown of the present invention, a closure assembly is designed to seal a high-pressure shell and tube heat exchanger and is configured as a "screw plug" type to maintain a seal at the heat exchanger tube sheet under pressure and under varying thermal loads. Sealing the closure assembly from the outside is preferably achieved by a diaphragm gasket assembly. The diaphragm gasket seal is preferably maintained by push bolts in the outer row, and the internal seal is preferably achieved by a second gasket located at the tube-sheet, which is installed by push bolts in the inner row. According to the specific embodiment shown, the load of the internal seal of the heat exchanger tube sheet is transmitted through a compression ring, an elastic torsion member, and a sleeve member. The elastic torsion member pivots in an area where it contacts the sleeve member and the compression ring.

[0023] During the assembly procedure of the specific embodiment shown of the present invention, a tube bundle with a tube sheet gasket is inserted into the heat exchanger tubes, and then a sleeve member, an elastic torsion member, and a closure plug member preferably having a cover-lock ring assembly are inserted. Further, a diaphragm and a diaphragm gasket are provided adjacent to the closure plug within the heat exchanger tubes to provide a leak-proof seal. To place it in the locked position, the closure plug member is removably fixed to the open-end channel of the heat exchanger tube by pivoting the closure plug member coaxially about the longitudinal axis of the heat exchanger in a single linear operation and preferably by rotating it less than one full rotation. It should be recognized that the load-bearing surfaces do not contact each other load-bearing until the final rotation of the closure plug is applied.

[0024] According to a particular embodiment shown of the present invention, the load-bearing surfaces of the closure plug and the open-end channel of the heat exchanger tube described above preferably have a first set of insertion holes provided (e.g., machined) on the closure plug and a complementary second set of insertion holes provided (e.g., machined) on a portion of the open-end channel of the heat exchanger tube, such that when the closure plug is rotated, the first set of insertion holes engages (interlocks with) the second set of insertion holes. One or more sets of insertion hole sections may be provided on the closure plug and / or the open-end channel of the heat exchanger to incorporate raised sections (e.g., rails) configured to (i) prevent excessive rotation, (ii) provide a bearing surface for insertion of the closure plug, and (iii) prevent damage to the load-bearing surfaces of both the closure plug and the open-end channel of the heat exchanger tube at the same time.

[0025] In another aspect, a heat exchanger assembly is provided having an elongated tubular heat exchanger enclosure that defines an internal chamber. A tube sheet is disposed within the internal chamber of the heat exchanger enclosure and separates the internal chamber into a shell side and a channel side. An internal portion is configured to removably receive a tube bundle disposed within the shell side of the internal chamber. An annular sleeve member is disposed within the channel side of the internal chamber of the heat exchanger enclosure. An annular elastic torsion member is disposed within the channel side of the internal chamber of the heat exchanger, such that the sleeve member is disposed between the tube sheet and the elastic torsion member. The elastic torsion member has an inner peripheral portion that can flex (displace) with respect to its outer peripheral portion in order to twist the elastic torsion member. Further, the heat exchanger can further include one or more of the following: i) a partition assembly, wherein the sleeve member is disposed within the channel side of the internal chamber of the heat exchanger enclosure and directs fluid from a port extending through the enclosure to at least two or more tubes within the tube bundle; ii) a tube sheet gasket disposed between the tube sheet and a shoulder formed within the internal chamber of the heat exchanger enclosure, and a bearing ring disposed within the internal chamber of the heat exchanger enclosure, wherein the elastic torsion member is disposed between the sleeve member and the bearing ring; iii) at least two ports extending through the enclosure to permit fluid to enter and exit the channel side of the internal chamber of the heat exchanger enclosure; iv) the elastic torsion member is configured to elastically flex up to an elastic flexure limit and plastically flex beyond the elastic flexure limit, such that the elastic torsion member elastically flexes to accommodate a differential in thermal expansion and to avoid damaging the components of the heat exchanger when the heat exchanger is under a preload and when under an expected pressure load and thermal load; v) the elastic torsion member is configured to pivot at a first contact area where the elastic torsion member contacts the sleeve member and at a second contact area where the elastic torsion member contacts the bearing ring; vi) the elastic torsion member has a square cross-section with rounded corners;vii) A plurality of elastic torsion members stacked in succession with respect to one another; viii) The elastic torsion members are configured to have an outer diameter “A” and an inner diameter “B”, where the outer diameter is less than the inner diameter of the channel of the internal chamber configured to receive the tube bundle, and where the ratio of “A” to “B” is less than 3; ix) The elastic torsion members are configured to have a height “H” that is about 50% of their elastic deflection limit and have a thickness “T”, such that the elastic torsion members plastically deform beyond their elastic deflection limit; x) A closure assembly for sealing the channel side of the internal chamber of the heat exchanger enclosure, where the closure assembly has a lock-ring member and a cover member removably fixed to the heat exchanger enclosure using a locking assembly; xi) The locking assembly has a plurality of spaced lock-ring insertion hole sections configured to mutually engage with corresponding channel insertion hole sections formed on the cylindrical inner surface portion of the heat exchanger enclosure; xii) A diaphragm disposed adjacent to the channel side of the internal chamber adjacent to the lock-ring and cover members, and a diaphragm gasket pressed against the diaphragm when the lock-ring member is removably fixed to the heat exchanger enclosure; xiii) The closure assembly further has a plurality of first elongated compression members provided along the outer diameter portion of the closure assembly for transmitting force to the first compression ring and thereby transmitting force to the rim portion of the diaphragm and the diaphragm gasket, and a plurality of second elongated compression members provided along the inner diameter portion of the closure assembly for transmitting force to the second compression ring when the closure assembly is removably fixed to the heat exchanger enclosure and thereby transmitting force to a portion of the diaphragm and thereby deflecting a portion of the diaphragm distally away from the cover member towards the elastic torsion members; xiv) The tube sheet, sleeve member, bearing ring, first and second compression rings, lock-ring, and first and second compression members are configured to maintain elasticity up to or exceeding the total axial load from preload, thermal load, and pressure load when fixing the closure assembly to the heat exchanger enclosure;xv) When the elongated compression member receives a preload, the compression member applies the preload to the first contact area of the elastic torsion member through a first axial load path, thereby transmitting the preload to the second contact area of the elastic torsion member through a torsion load path passing through the elastic torsion member, and thereby transmitting the preload to the tube sheet gasket through a second axial load path; xvi) The pressure load from the process fluid in the heat exchanger is within a standard predetermined threshold range, and the elastic torsion member is configured to elastically deform so as to allow its outer peripheral portion to move axially towards the closure assembly. The pressure load from the process fluid in the heat exchanger enclosure reduces the load on the elastic torsion member by deforming the closure assembly distally from the tube sheet. The elastic torsion member is configured to elastically flex up to the elastic flexure limit and plastically flex beyond the elastic flexure limit. As a result, the elastic torsion member accommodates the differential thermal expansion, thereby avoiding damaging the components of the heat exchanger when the heat exchanger is under preload and under the expected pressure load and thermal load. ;

[0026] In another aspect, a process for assembling a tube heat exchanger assembly is provided that includes providing an elongated heat exchanger enclosure having an internal chamber, defining a longitudinal axis, and having an open cylindrical channel end. A closure assembly is provided having a locking assembly configured to be fixed to the open cylindrical channel end of the elongated heat exchanger enclosure. The locking assembly of the closure assembly is axially inserted into the open cylindrical channel end along the longitudinal axis of the internal chamber of the heat exchanger such that the respective load-bearing surfaces of the internal walls of the closure assembly and the elongated heat exchanger enclosure do not contact each other. The closure assembly is pivoted about the longitudinal axis of the elongated heat exchanger enclosure such that the locking assembly is removably fixed to a cooperating locking assembly provided on the internal wall of the elongated heat exchanger enclosure, whereby the load-bearing surfaces contact each other and, as a result, a load is transmitted between the closure assembly and the elongated heat exchanger. Further, the process for assembling the tube heat exchanger can further include one or more of the following: i) the closure assembly is pivoted less than 360 degrees such that the locking assembly of the closure assembly is removably fixed to a cooperating locking assembly provided on the internal wall of the elongated heat exchanger enclosure; ii) the locking assembly of the closure assembly and the locking assembly provided on the internal wall of the elongated heat exchanger enclosure cooperatively form a bayonet-type locking assembly; iii) the bayonet-type locking assembly has a plurality of spaced-apart lock-ring insertion hole sections provided on the outer surface portion of the closure assembly and a plurality of spaced-apart lock-ring insertion hole sections provided on the internal wall of the elongated heat exchanger enclosure configured to interfit with corresponding channel insertion hole sections formed on the closure assembly.(iv) Before inserting the lock assembly, along the longitudinal axis of the elongated heat exchanger enclosure, axially insert the tube sheet gasket into the open cylindrical channel end so as to be disposed adjacent to the channel shoulder configuration formed within the elongated heat exchanger enclosure; axially insert the tube sheet into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the tube sheet gasket to define the shell side and the channel side within the internal chamber of the elongated heat exchanger enclosure, wherein the internal chamber is configured to removably receive a tube bundle disposed within the shell side of the internal chamber; axially insert the annular sleeve member into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the tube sheet; axially insert the elastic torsion member into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the sleeve member; insert the bearing ring into the open end of the cylindrical channel along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the elastic torsion member; and insert the diaphragm into the open end of the cylindrical channel along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the bearing ring;v) Adjusting a plurality of first elongated outer compression members provided along the outer diameter portion of the closure assembly that extends coaxially along the longitudinal axis of the closure assembly, thereby transmitting force to the first compression ring, thereby transmitting force to the rim portion of the diaphragm and the diaphragm gasket, thereby pressing the diaphragm gasket against the diaphragm; and when fixing the closure assembly to the heat exchanger enclosure, adjusting a plurality of second elongated inner compression members provided along the inner diameter portion of the closure assembly that extends coaxially along the longitudinal axis of the closure assembly, thereby transmitting force to the second compression ring, thereby transmitting force to a portion of the diaphragm to deflect a portion of the diaphragm distally away from the closure assembly toward the elastic torsion member of the heat exchanger assembly; vi) The tube sheet, sleeve member, first and second compression rings, closure assembly, and respective first and second elongated compression members are configured to maintain elasticity up to or exceeding the total axial load from preload, thermal load, and pressure load when fixing the closure assembly to the heat exchanger enclosure; vii) When the elongated compression member receives a preload, the compression member applies the preload to the first contact area of the elastic torsion member through the first axial load path, thereby transmitting the preload to the second contact area of the elastic torsion member through the torsion load path through the elastic torsion member, thereby transmitting the preload to the tube sheet gasket through the second axial load path; viii) The torsion load is subject to an increase in stress and resistance to torsional rotation, thereby enabling the first contact area of the elastic torsion member to move toward the tube sheet; ix) Positioning a cylindrical cover member having an outer diameter that will be concentrically fixed to the inner portion of a cylindrical lock ring member that defines a cylindrical outer surface portion and an inner portion of cylindrical shape of the closure assembly, the outer surface portion being equipped with a lock assembly of the closure assembly.;

[0027] In another aspect, there is provided a closure assembly configured to be removably fixed to an open channel end of an internal chamber of a heat exchanger assembly having a cylindrical lock ring member defining a cylindrical outer surface portion and an internal portion of cylindrical shape. The outer surface portion is equipped with a plurality of spaced lock ring insertion hole sections configured to mutually engage with corresponding channel insertion hole sections formed on the cylindrical inner surface portion of the heat exchanger assembly. A fixed cylindrical cover member is concentric with the internal portion of the lock ring member. Additionally, the closure assembly can further have one or more of the following: i) the cover member is removably fixed to the lock ring member, where the lock ring member has an inner diameter surface having a shoulder configuration configured to receive a cooperating shoulder configuration provided on the outer diameter surface of the cover member; ii) each lock ring insertion hole section extends at a predetermined angle from the outer surface portion of the lock ring member and is configured to mutually engage with a corresponding angled insertion hole section provided in each channel insertion hole section formed on the cylindrical inner surface portion of the heat exchanger assembly; iii) an upwardly extending flange member provided on the lock ring member configured to stop rotation of the closure assembly into the internal chamber of the heat exchanger assembly; iv) a diaphragm configured to be disposed adjacent to the lock ring and the cover member; v) a plurality of adjustable elongate outer lock ring compression members removably fixable within the lock ring member, each elongate outer lock ring compression member passing through a respective hole formed coaxially with the longitudinal axis within the lock ring member, thereby transmitting force to a first compression ring, thereby transmitting force to the rim portion of the diaphragm, and a diaphragm gasket pressed against the diaphragm, such that when removably fixing the lock ring member to the internal chamber of the tubular heat exchanger assembly, by adjusting the elongate outer lock ring compression members, the diaphragm is disposed intermediate the diaphragm gasket and the first compression ring member;vi) A plurality of adjustable elongate inner cover compression members that can be removably fixed within the cover member, such that when the closure assembly is removably fixed to the open end of the internal chamber of the heat exchanger assembly, each elongate inner cover compression member passes through a respective hole formed within the cover member coaxial with the longitudinal axis, thereby transmitting a force to the second compression ring, thereby transmitting a force to a portion of the diaphragm, thereby deflecting a portion of the diaphragm distally away from the cover member towards the internal chamber of the heat exchanger assembly; vii) When removably fixing the closure assembly to the open end of the internal chamber of the heat exchanger assembly, the first and second compression rings, the compression rod, and the compression bolt are configured to maintain elasticity up to and including a total axial load from preload, thermal load, and pressure load; viii) The outer surface portion of the lock member is equipped with an upright groove formed substantially perpendicular to the longitudinal axis of the lock-ring member, and this upright groove is configured to be slidably received within a corresponding notch formed within the inner surface portion of the heat exchanger assembly perpendicular to the longitudinal axis of the heat exchanger axis, thereby facilitating insertion of the lock-ring member into the inner surface portion of the heat exchanger assembly.;

[0028] In another aspect, an operating method is provided for a heat exchanger assembly having a tubular heat exchanger enclosure configured to accommodate differences in thermal expansion of internal components within an internal chamber of the heat exchanger enclosure during heating and cooling sequences, the operating method including subjecting an elastomeric torsion member to a preload within the internal chamber of the heat exchanger enclosure, such that the elastomeric torsion member receives a torsional load and elastically deflects thereby corresponding to the preload. A thermal load is received by the heat exchanger assembly to thermally expand internal components within the internal chamber of the heat exchanger enclosure differently, such that the torsional load received by the elastomeric torsion member increases and further elastically deflects thereby corresponding to the thermal load. Additionally, the operating method for the heat exchanger can further include one or more of the following: i) receiving a pressure load within the internal chamber of the heat exchanger enclosure by elastically deflecting a closure assembly removably attached to the heat exchanger enclosure for the purpose of accommodating the pressure load, thereby reducing the torsional load received by the elastomeric torsion member; ii) thermally expanding internal components differently includes accommodating at least the difference in thermal expansion of a bearing ring, an elastomeric torsion member, a sleeve member, and a tube sheet without plastically deforming at least the bearing ring, the elastomeric torsion member, the sleeve member, and the tube sheet; ii) an elongated compression member is used to preload the elastomeric torsion member, such that the compression member applies a preload to a first contact area of the elastomeric torsion member through a first axial load path, thereby transmitting the preload to a second contact area of the elastomeric torsion member through a torsional load path through the elastomeric torsion member, thereby transmitting the preload to a tube sheet gasket through a second axial load path; iii) the elastomeric torsion member is configured to pivot at a first contact area where the elastomeric torsion member contacts the sleeve member and at a second contact area where the elastomeric torsion member contacts the bearing ring;(iv) Insert the tube sheet gasket axially into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the channel shoulder configuration formed within the elongated heat exchanger enclosure; insert the tube sheet axially into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the tube sheet gasket to define the shell side and the channel side within the internal chamber of the elongated heat exchanger enclosure, wherein the internal chamber is configured to removably receive a tube bundle disposed within the shell side of the internal chamber; insert the annular sleeve member axially into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the tube sheet; insert the elastic torsion member into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the sleeve member; insert the bearing ring into the open end of the cylindrical channel along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the elastic torsion member; and insert the diaphragm into the open end of the cylindrical channel along the longitudinal axis of the elongated heat exchanger enclosure so as to be adjacent to the bearing ring; (v) Attach a closure assembly to the open end portion of the internal chamber, the closure assembly having a diaphragm and a bearing ring that can flex, and further having a mechanism for applying a preload to the elastic torsion member.;

[0029] These and other unique features of the closure assembly described herein will become more readily apparent from the following description and the accompanying drawings.

[0030] The drawings may be referred to in order to enable those skilled in the art of the disclosed system and method to readily understand how to make and use the same system and method as shown in various non-limiting examples of aspects of the invention according to the specific embodiments shown.

Brief Description of the Drawings

[0031]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0032] Next, the present invention will be more fully described with reference to the accompanying drawings showing specific embodiments of the present invention. As will be recognized by those skilled in the art, since the illustrated embodiments described below are merely examples of the present invention that can be embodied in various forms, the present invention is in no way limited to the illustrated embodiments. Therefore, it should be understood that any structural and functional details disclosed herein are not to be construed as limiting, but rather as a basis for the claims and as exemplary teaching for those skilled in the art to employ the present invention in various forms. Also, the terms and phrases used herein are not intended to be limiting, but rather are intended to provide an understandable description of the present invention.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice and testing of the present invention, the exemplary methods and materials are described herein. All patent publications referred to herein are incorporated herein by reference to disclose and describe the relevant methods and / or materials when the publications are cited.

[0034] It should be noted that, as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a stimulus" includes a plurality of such stimuli, and reference to "signal" includes reference to one or more signals and equivalents known to those skilled in the art, and so on.

[0035] To avoid obscuring the present disclosure, well-known components, materials, or methods are not necessarily described in detail. Any specific structural or functional details disclosed herein are not to be construed as limiting, but rather are to be construed merely as a basis for the claims and as an exemplifying basis for teaching one of ordinary skill in the art to employ the present invention in a variety of forms.

[0036] Here, the present disclosure will be described more fully, but not all embodiments of the present disclosure are necessarily shown. Also, many modifications can be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope of the invention.

[0037] It should be appreciated that the present invention solves many of the problems associated with prior art heat exchanger closure assemblies. For example, referring to FIG. 1A, a prior art closure assembly for a shell and tube heat exchanger, as described in U.S. Patent No. 4,750,554, is depicted. One section of a shell and tube heat exchanger is shown, where the shell and channels include a tube bundle. The channels have ports that provide access paths for fluid to enter and exit the tubes of the bundle. An end closure assembly or "plug" is composed of a lock ring 9 and a cover 19, thereby incorporating a diaphragm 8 and a diaphragm gasket 10. The closure plug assembly is removable, thereby allowing insertion and removal of a removable tube bundle, while also allowing maintenance of a tight seal and absorption of loads that occur under high pressure. The open channels of the heat exchanger are closed at their ends by the closure plug assembly (i.e., cover 19 and lock ring 9). The lock ring member 9 includes a mechanism for sealing the exchanger channels against the diaphragm 8 by compressing the gasket 10 using bolts 11 and a compression ring 20.

[0038] The shell-side fluid is separated from the fluid in the channels entering the tubes (not shown) by the tube sheet 1 and the tube sheet gasket 6. Usually, a heat exchanger requires a partition assembly to accommodate a tube-side flow configuration having two passages. The partition assembly can have a sleeve member 2, a partition plate 3, a partition cover 4, and / or a ring 17 to direct the fluid from the channel inlet nozzle through two or more tube passages to the outlet port. One skilled in the art will recognize that the partition may be applied at either the inlet or the outlet.

[0039] Continuing to refer to the prior art heat exchanger of FIG. 1A, a lock ring member 9 is secured to the channel of the shell of the heat exchanger using threads, where the lock ring 9 has male threads and the channel has corresponding female threads. It is to be understood and recognized that the threaded portion is a load-bearing surface, and as a result, when assembling the heat exchanger, the threaded portion absorbs the preload of the bolts. Further, during operation of the heat exchanger, a hydrostatic load is applied to the plug cover assembly 19 and this hydrostatic load is transmitted directly to the threaded portion mentioned above.

[0040] Next, referring to FIG. 1B, there is shown a partial cross-sectional view of a tubular heat exchanger-closure assembly constructed in accordance with an illustrated embodiment of the present invention, generally designated by reference numeral 100. Similar to the prior art heat exchanger of FIG. 1A, heat exchanger 100 is a shell and tube heat exchanger having an enclosure 70, where here the enclosure 70 has a shell member 15 that is integrally formed with or joined to channel member 7, where here the enclosure 70 is configured to receive a tube bundle (not shown). Heat exchanger channel member 7 preferably has at least two ports that provide access paths for fluid flow to enter and exit the tubes of the inserted bundle. An end closure assembly or "closure plug" preferably consists of an annular lock ring member 9, compression rings 21 and 22, and an annular cover member 19. Further, a diaphragm 8 and a diaphragm gasket 10 are included. The closure plug is removable, thereby allowing a removable tubular bundle to be inserted and withdrawn, while also being able to maintain a tight seal and absorb the loads that occur under high pressure during operation of heat exchanger 100. The open end of channel member 7 is closed (sealed) by a closure plug (e.g., cover 19 and lock ring 9). Lock ring member 9 preferably includes means for sealing heat exchanger channel 7 against diaphragm 8 by compressing gasket 10 using bolts 12, push rods 14, and compression ring 21. As shown in FIG. 1B, cover member 19 is removably fixed to lock ring member 9, such that lock ring member 9 preferably has an inner diameter surface formed to have a cooperating dish hole configuration that receives a cooperating dish hole configuration provided on the outer diameter surface of cover member 9. According to the illustrated embodiment, the smallest inner diameter of cover member 19 is preferably smaller than the largest outer diameter of lock ring member 9, thereby forming a dish hole configuration therebetween.

[0041] Continuing to refer to FIG. 1B, the shell-side fluid flow is separated from the fluid flow in the channels leading to the tubes (not shown) by the tube sheet 1 and the tube sheet gasket 6. The heat exchanger 100 typically requires a partition assembly to accommodate a tube-side flow configuration having two passes. However, those skilled in the art will recognize that aspects of the present invention of the present disclosure may be used with a single-pass heat exchanger or a heat exchanger having more than two passes. In this embodiment, the partition assembly has a sleeve member 2, a partition plate 3, and a partition cover 4 to direct fluid from the channel inlet nozzle through two or more tube passes to the outlet port. It will be understood that the partition may be applied to either the inlet or the outlet.

[0042] The lock ring member 9 of the closure plug assembly is secured to the open end portion of the channel 7 of the shell of the heat exchanger 100, preferably using a bayonet-style lock assembly preferably configured from the formed insertion hole sections 23A and 23B. Referring now to FIGS. 4-6 (and continuing to refer to FIG. 1B), the lock ring member 9 is preferably formed to have an insertion hole section 23A formed on the outer circumferential surface portion of the ring member 9, each insertion hole section 23A being separated by a section 24A that does not have a partial cylindrical insertion hole. Similarly, the open end portion of the channel 7 of the heat exchanger 100 is preferably formed to have an insertion hole section 23B formed on the inner circumferential end portion of the inside of the heat exchanger channel 7, which is separated by a section 24B that does not have a partial cylindrical insertion hole. A plurality of spaced lock ring insertion hole sections 23A of the lock ring 9 are configured to interfit with corresponding channel insertion hole sections 23B formed on the cylindrical inner surface portion of the channel 7 of the heat exchanger 100.

[0043] According to the illustrated embodiment, during the assembly of the closure plug members (e.g., the ring member 9 and the cover member 19) within the end portion of the channel 7 of the heat exchanger 100, the lock ring member 9 is coaxially inserted along the longitudinal axis of the internal chamber of the heat exchanger 100 into the open cylindrical channel end 7. As a result, unlike the prior art structures and methods mentioned above, no load is transmitted between the ring member 9 of the closure plug assembly and the heat exchanger 100 at the respective load-bearing surfaces of the inner diameter of the ring member 9 and the open cylindrical channel end 7 of the heat exchanger 100. Load is transmitted from the heat exchanger 100 to the closure plug member only after the lock ring member 9 has been rotated for a locking engagement with the elongated heat exchanger 100. This is achieved by rotating the ring member 9 of the closure plug assembly about the longitudinal axis of the internal chamber of the elongated heat exchanger 100 to removably fix the insertion hole section 23A of the ring member 9 to a cooperating insertion hole section 23B provided on the inner diameter of the open cylindrical channel end 7 of the heat exchanger 100, thereby facilitating the transmission of load from the channel 7 of the heat exchanger 100 to the ring member 9 of the closure plug assembly. It should be recognized that the ring member 9 is rotated less than 360 degrees to removably fix (interfit) the insertion hole section 23A of the ring member to the corresponding insertion hole section 23B formed on the inner diameter portion of the open cylindrical channel end 7 of the heat exchanger 100. In one embodiment, the ring member 9 is rotated approximately 22.5 degrees, where each of the insertion hole sections 23A and 23B extends over approximately 22.5 degrees along the circumferential portion of the ring member 9 and the open cylindrical channel end 7 of the heat exchanger 100 where they are respectively formed.

[0044] It should further be recognized that in other embodiments, the lock ring member 9 and the cover member 19 may be integrated so as to be a single integral component. Additionally, in other embodiments, the lock ring member 9 may be divided into two or more components. In another embodiment, the insertion hole sections 23A and 23B may have different shapes or designs from each other at a portion of the lock ring member 9.

[0045] According to the embodiment shown, the above-described insertion hole configuration may be configured to have eight sections, and as a result, there are eight insertion hole sections (23A and 23B) and regions (24A and 24B) without insertion holes, which are respectively provided on the lock ring member 9 and on the inner diameter of the open cylindrical channel end 7 of the heat exchanger 100. However, those skilled in the art will readily recognize that the number of insertion hole regions may vary without departing from the aspects of the invention of the present disclosure. For example, there may be one, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve insertion hole regions combined with regions without one, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve insertion holes.

[0046] During the assembly of the closure plug with respect to the open channel 7 of the heat exchanger, in contrast to the prior art described above, the load-bearing surfaces of the insertion holes 23A and 23B are not damaged during the insertion of the closure plug assembly into the heat exchanger channel 7. Also, this configuration ensures that the diaphragm 8 is properly aligned with respect to the heat exchange channel 7. Additionally, it should be recognized that the above-described insertion hole sections 23A and 23B may be formed (e.g., machined) to have a screw pitch such that during rotation, the closure plug assembly is axially advanced inwardly into the channel 7 of the heat exchanger 100.

[0047] Continuing to refer to FIGS. 4 - 6, according to a particular embodiment, the rail member 25 in the upright direction is formed so as to be adjacent to the channel insertion hole 23B or the lock - ring insertion hole 23A, or adjacent to both of them, thereby preventing the insertion holes 23A, 23B from contacting any metal surface during insertion. It should be recognized that it may be preferable to provide the rail 25 on the lock - ring member 9. The reason is that during manufacturing, the channel 7 of the heat exchanger 100 cannot be independently rotated, while the lock - ring 9 can be independently rotated, which can facilitate manufacturing.

[0048] According to another embodiment shown, an annular stop member 26 (flange) in the upright direction can be provided on the lock - ring member 9, which corresponds to the location of the diaphragm 8 referred to herein. The stop member 26 preferably extends around the outer peripheral portion of the lock - ring member 9, so that a slot - shaped cavity having no insertion hole formed when the lock - ring 9 is rotated to a fixed position is surely covered, preventing foreign matter from entering. It should be noted that this promotes the accurate positioning of the cover member 19 and the diaphragm 8 without the need to "estimate" based on external measurements. This is in contrast to the prior - art screw - plug design in which the location of the lock - ring member can be determined by the number of turns and the screw pitch that can incorporate changes. It should be recognized that the configuration of the stop member 26 shown in FIG. 6 is understood as an exemplary configuration for the reason that other configurations may be provided to surely cover the slot - shaped cavity having no insertion hole formed when the lock - ring 9 is rotated to a fixed position and prevent foreign matter from entering.

[0049] As shown in FIGS. 4 - 6, the insertion hole sections 23A, 23B are preferably aligned so as to be perpendicular to the longitudinal axis of the lock ring member 9 and the channel 7 of the heat exchanger 100. In other embodiments, the insertion hole sections may be formed (e.g., machined) at an angle with respect to the longitudinal axis of the lock ring member 9 and the channel 7 of the heat exchanger 100, such that upon rotation of the lock ring member, the lock ring member 9 advances into the channel 7 by a slightly greater distance. It should further be recognized that the size and shape of the insertion holes for the insertion hole sections 23A and 23B need not be the same in all insertion hole sections, provided that the length of the lock ring member 9 and the assembly of the channel 7 allow the lock ring member 9 to be freely inserted into the channel 7 and that the insertion hole sections 23A and 23B of the lock ring member 9 and the channel 7 are in correspondence with each other.

[0050] Next, referring particularly to FIG. 6, the lock ring member 9 of the closure plug assembly is shown inserted into the open end of the channel 7 of the heat exchanger. It will be appreciated that the lock ring member 9 is inserted into the channel 7 such that regions 24A, 24B, which do not have respective insertion holes of the lock ring 9 and the channel 7, are allowed to slide past the insertion hole regions 23A, 23B. For example, the closure plug assembly can be installed into the heat exchange channel 7 at an angle of about 22.5° from the orientation of the final locked state (lock ring member 9), such that regions 24A, 24B, which do not have respective insertion holes of the lock ring 9 and the channel 7, are allowed to slide past the insertion hole regions 23A, 23B, thereby preventing the load-bearing surface from contacting the rail. When the closure plug member is fully inserted into the channel 7 of the heat exchanger, the closure plug member is rotated to the locked position. For example, the closure plug assembly can be swiveled clockwise by 22.5° to the locked position. This rotation can be achieved in a variety of ways, for example, using a rod bolted to the lock ring member 9 to provide the leverage action sufficient to manually swivel the lock ring member 9, using a cable and a crane attached to the lock ring member 9 to provide an upward tangential force, or using a circular rack gear mounted to the heat exchanger channel 7 and a corresponding pinion gear mounted to the lock ring member 9 (a lever is used to swivel the pinion gear, thereby applying a tangential force to rotate the lock ring member 9). Another safety feature may be provided, where a notch 27 is provided in one set of insertion holes of the lock ring member 9 and a corresponding guide notch 28 is formed in the open end portion of the channel 7 of the heat exchanger, such that the lock ring member 7 can be inserted in only one orientation with respect to the channel 7.

[0051] Referring to FIG. 4, the marks on the outer part of the lock ring 9 and the channel 7 further emphasize the exact orientation of the lock ring member 9, and the upright stopper member 29 can be formed in the open end portion of the channel 7 so as to be adjacent to the region 24B having no insertion hole, and has a width larger than the width of the rail 27 provided in the insertion hole section 23A, whereby each of the insertion holes 23A and 23B cannot be accidentally rotated or permanently engaged during insertion, while also assisting in guiding the insertion of the lock ring 9, and as a result, maintaining the state in which the insertion holes 23A and 23B are protected.

[0052] Next, referring to FIGS. 1B and 3, the diaphragm 8 is preferably engaged with the channel cover member 19, and as a result, the pressure load from the fluid flow in the channel 7 of the heat exchanger is transmitted across the diaphragm 8 to the channel cover member 19. Further, the pressure load applied to the channel cover member 19 is transmitted to the lock ring member 9. The channel 7 is preferably sealed by the diaphragm gasket 10. The diaphragm gasket 10 is preferably compressed by a plurality of compression bolts 12 and push rods 14 (collectively referred to as "compression members") provided axially along the outer row of the lock ring member 9, and the plurality of compression bolts 12 and push rods 14 pass through screw holes preferably formed in the lock ring member 9. These compression bolts 12 and push rods 14 transmit force to the rim portion of the diaphragm 8 and its diaphragm gasket 10 through a loose outer compression ring 21 provided between the lock ring member 9 and the diaphragm 8. As will be described later, it should be understood that depending on the diameters of the elastic torsion member 60 and the bearing ring 50, the inner row of compression bolts 11, 13 may be positioned along the radius of either the annular cover member 19 or the lock ring 9 member.

[0053] The diaphragm 8 is preferably configured to flex a specific amount under the preload of the bolts and under internal pressure, where, if the closure - plug member assembly is not sufficiently axially inserted inwardly into the channel 7 of the heat exchanger 100, the outer - row push - bolts 14 of the lock - ring member 9 need to be further advanced to be sealed by the diaphragm gasket 10, and the inner - row push - bolts 13 of the cover member 19 need to be further advanced to be sealed by the tube - sheet gasket 6, whereby the diaphragm 8 will deform more when pressure is applied to the channel 7. During manufacture, dimensional inspection can be carried out to ensure that machining tolerances can be reliably tolerated for proper placement of the closure. After manufacture, shims can be added between the diaphragm 8 and the closure - plug assembly. Alternatively, the insertion holes on the closure - plug assembly can be machined to have a pitch such that rotating the closure - plug assembly axially inwardly into the channel 7 of the heat exchanger 100. The closure - plug assembly is rotated until it contacts the diaphragm 8, then the outer - row push - bolts 14 are advanced to compress the gasket 21, and then the outer - row push - bolts 14 are retracted so that the closure - plug can be further rotated to minimize the gap between the closure - plug assembly and the diaphragm 8. When dimensional inspection is carried out, the closure - plug assembly is inserted into the channel 7 of the heat exchanger 100 in a single linear movement, which can be achieved using a fork - lift truck, crane, or combination of other devices, as would already be necessary for handling the tube bundle, without the need for special tools and equipment as in the prior art mentioned above.

[0054] Referring now to FIGS. 1B and 3, it should be recognized that during assembly, when the compression bolts 13 in the inner row of the cover member 19 are tightened, the axial load is transmitted through the push rod 11 to the (inner) compression ring 22 in a relaxed state, and through the diaphragm 8, to the tube sheet mounting assembly composed of the bearing ring 50, the elastic torsion member 60, and the sleeve member 2. As a result, it is recognized that the tube sheet gasket 6 is pressed against the rear surface of the tube sheet 1 and the shell 15. This axial load is referred to as a preload. It should be recognized that this preload prevents leakage caused by the pressure difference between the shell side and the tube side of the heat exchanger 100.

[0055] It should further be recognized that the tube sheet mounting assembly mentioned above preferably accommodates the thermal load that causes a difference in thermal expansion between the channel 7, the tube sheet 1, and the above-mentioned tube sheet mounting assembly (for example, the bearing ring 50, the elastic torsion member 60, and the sleeve member 2). The difference in thermal expansion is caused by two mechanisms. The first mechanism is that the process fluid flow, which is mostly shielded from the channel 7 by the sleeve member 2 but in close contact with the internal components, is at a high temperature, and there is heat loss to the surrounding environment in the channel 7 or the fluid temperature changes rapidly and the temperature of the relatively thin internal components changes more rapidly than that of the relatively thick channel. This is the mechanism when the channel 7 is at a lower temperature than the tube sheet 1 and the tube sheet mounting assembly (for example, the bearing ring 50, the elastic torsion member 60, and the sleeve member 2). Such a state necessarily occurs during startup (heating), during upset or plant trip, and during the subsequent recovery of the operating temperature. The second mechanism is the case where the material used to form the channel 7 has a lower coefficient of thermal expansion than the materials used for the tube sheet 1 and the tube sheet mounting assembly (for example, the bearing ring 50, the elastic torsion member 60, and the sleeve member 2). For example, this is often seen when carbon steel is used for the channel 7 and stainless steel is used for the internal components of the heat exchanger.

[0056] When the total thermal expansion of the tube sheet 1 and the tube sheet mounting assembly (for example, the bearing ring 50, the elastic torsion member 60, and the sleeve member 2) is greater than the total thermal expansion of the channel 7, the resulting thermal expansion difference must be accommodated by deformation within the heat exchanger 100. Due to the relatively high stiffness of the channel 7 required to safely store pressure, the deformation mainly occurs in the members with relatively low stiffness within the tube sheet mounting assembly (for example, the bearing ring 50, the elastic torsion member 60, and the sleeve member 2). If the stress generated by this deformation exceeds the yield stress of the member, irreversible deformation, i.e., plastic deformation, occurs. Due to the presence of through-holes formed in the sleeve member 2 to allow fluid to enter the internal chamber of the heat exchanger 100, the sleeve member 2 does not have a uniform stiffness as a whole. Therefore, there is a possibility that the sleeve member 2 undergoes non-uniform plastic deformation due to the thermal load, and as a result, even if the inner row of compression bolts 13 is simply tightened again, the load applied to the gasket 22 cannot be restored. When the thermal load returns to normal, the axial compression load remaining within the tube sheet mounting assembly (bearing ring 50, elastic torsion member 60, and sleeve member 2) decreases to less than the load applied when tightening the compression bolts 13 of the cover member. This load may decrease to less than the minimum load required to seal the tube sheet - gasket 6 when the plastic deformation is very large. This results in undesirable leakage between the shell side and the tube side of the heat exchanger 100.

[0057] According to the illustrated embodiment, a compliant member, described below, is provided to accommodate thermal expansion differences without causing plastic deformation within the heat exchanger. The compliant member is obtained by implementing an elastic torsion member 60, as shown in FIGS. 1B and 2. As shown, the annular elastic torsion member 60 preferably contacts the sleeve member 2 on the side facing the tube sheet 1 at the first contact area 61 of the outer peripheral portion, near its outer diameter, and contacts the bearing ring 50 on the side facing the diaphragm 8 at the second contact area 63 of the inner peripheral portion, near its inner diameter. When the inner compression bolt 13 receives a preload, the axial force is transmitted through the elastic torsion member 60 at the contact areas 61 and 63 mentioned above. These forces applied at various radii of the elastic torsion member 60 create a torsional load on the elastic torsion member 60, as a result of which its inner peripheral portion can bend axially relative to its outer peripheral portion to twist the elastic torsion member 60. As a result, this torsional load is subject to an increase in stress and resistance to torsional rotation, thereby enabling the outer diameter of the elastic torsion member 60 to move towards the diaphragm 8 of the closure plug assembly and its inner diameter to move towards the tube sheet 1.

[0058] It should be recognized that the bearing ring 50 protects the diaphragm 8 so as not to be damaged by contacting the elastic torsion member 60 during rotation. During operation of the heat exchanger 100, the pressure load deforms to separate the closure plug assembly from the tube sheet 1, thereby reducing the load applied to the elastic torsion member 60, but this load will increase due to the thermal expansion difference. It should be understood that the elastic torsion member 60 is designed and configured to elastically deform upward until it reaches the maximum required thermal expansion difference. When the load is maintained below this maximum threshold during operation of the heat exchanger, when the thermal load and pressure load are removed, the load on the elastic torsion member 60 will return to the initial preload. According to the illustrated embodiment, the elastic torsion member 60 can be formed to have a deflection range between 25 mm and 75 mm. However, it should not be understood that the elastic torsion member 60 is limited only to the above deflection range because it can be configured according to the scale of the dimensional size of the heat exchanger 100. However, during an unintended thermal cycle of the process fluid, etc., if an excessive thermal expansion difference occurs, the elastic torsion member 60 plastically deforms to limit the load applied to the closure plug assembly, thereby preventing failure of the seal provided by the closure plug assembly and / or the diaphragm 8. It should be recognized that when the thermal load and pressure load are removed, the load on the elastic torsion member 60 will decrease to less than the initial preload and may also decrease to about zero. The elastic torsion member 60 can be formed of a material that is not subject to corrosion, creep, and strength loss at high temperatures, and preferably can be formed of a high-nickel alloy including (but not limited to) Inconel 625 and Inconel 718.

[0059] Next, with reference to FIG. 2, exemplary relevant dimensions for the design of the elastic torsion member 60 will be described. It should be understood that dimension "a" is the outer diameter of the elastic torsion member 60, dimension "b" is the inner diameter of the elastic torsion member 60, dimension "h" is the height of the elastic torsion member 60, and dimension "t" is the thickness of the elastic torsion member 60. Dimension "a" is smaller than the inner diameter defined by the channel 7 of the heat exchanger 100, thereby providing clearance for radial thermal expansion and rotation under load. To generate a torsional load in the elastic torsion member 60 due to an axial load, the ratio a / b is greater than 1 and preferably less than 3. Dimension "h" is approximately 50% of its elastic deflection limit when a preload and operating loads (pressure load and thermal load) are applied. Dimension "t" is selected such that the axial load is less than the maximum allowable load applied to the tube sheet gasket 6 when the elastic torsion member 60 is compressed by the sum of the displacement due to the preload and the design thermal expansion difference, so that the elastic torsion member 60 will deform elastically. The material of the elastic torsion member 60 is selected to plastically deform beyond this maximum allowable load. It should be recognized that the tube sheet 1, the sleeve member 2, the bearing ring 50, the compression ring 22, the compression rod 11, and the compression bolt 13 are designed to maintain elasticity up to and beyond the total axial load from the preload, thermal load, and pressure load.

[0060] In the illustrated embodiments (e.g., FIGS. 2 and 3), it should be recognized that the elastic torsion member 60 is understood to have a square cross-section with rounded corners. In the alternative embodiments shown, other cross-sectional configurations for the elastic torsion member 60 may be used, including a rectangular shape or a shape having generally rounded sides. Additionally, in the embodiments shown herein, the tube sheet mounting assembly has a single elastic torsion member 60. In some embodiments, the elastic torsion member 60 may be designed to have a high stiffness in order to meet the design requirements for the minimum pressure applied to the tube sheet gasket 6 and the maximum displacement applied to the diaphragm 8, such that as a result, the maximum thermal expansion may not be accommodated without plastic deformation. In such an example, two or more elastic torsion members 60 may be stacked in series (i.e., continuously), thereby improving the thermal expansion capacity. For example, FIG. 7 shows a design using three elastic torsion members 60. It should be recognized that when an odd number of elastic torsion members 60 are utilized, the inner compression bolts (11, 13, and 22) may be within the common bolt circle radius provided in the cover plate member 19. When an even number of elastic torsion members 60 are utilized, the inner compression bolts are preferably located at a larger bolt circle radius within the lock ring member 9. Further, in a design having a plurality of elastic torsion members 60, an alignment ring is preferably included to maintain alignment with each other.

[0061] Next, referring to FIG. 3, the behavior of the diaphragm 8 after the compression bolts 13 and 14 receive a preload and pressure is applied from the channel 7 of the heat exchanger 100 is shown. As shown, at the diaphragm gasket 10, the compression ring 21 is displaced away from the lock ring member 9 of the closure plug assembly, thereby compressing the diaphragm 8 and the diaphragm gasket 10. When pressure is applied from the channel 7 of the heat exchanger 100, the diaphragm 8 is deformed until it comes to rest in contact with the lock ring member 9 and the cover plate member 19 within the region 31. Thereby, a high bending strain area is formed within the diaphragm 8 at a radius smaller than the radius of the compression ring 21. To prevent the diaphragm 8 from rupturing, the compression ring 21 is preferably wide and is formed to have a curved surface for reducing bending strain.

[0062] Similar to the outer compression ring 21, the inner compression ring 22 is displaced away from the cover member 19 of the closure plug assembly, thereby compressing the diaphragm 8 and the tube sheet mounting assembly. As shown, when pressure is applied from the channel 7 of the heat exchanger, the diaphragm 8 bends on both sides of the inner compression ring 22, thereby forming two high bending strain areas within the diaphragm 8. To prevent the diaphragm 8 from rupturing, the inner compression ring 22 can also be made wide and can be provided with a curved surface for reducing bending strain.

[0063] It should be appreciated that in the specific embodiments shown above, for a particular application, the various non-limiting embodiments described herein can be used in separate forms, combined forms, or selectively combined forms. Further, some of the various features of the above non-limiting embodiments may be used without the corresponding use of other features described. Therefore, the above description should be regarded as merely illustrative of the principles, teachings, and exemplary embodiments of the present invention and should not be regarded as limiting the present invention.

[0064] For example, there are A-style and B-style bleach lock closures. The embodiments shown above relate to the A-style commonly used in feed effluent type applications, where the shell-side fluid and the tube-side fluid are independent, and as a result, the tube sheet can be designed for only the pressure difference. However, since the embodiments shown also include the B-style closure, it should not be understood as being limited to only such A-style bleach lock closures. In the B-style closure, for example, as shown in FIG. 8, the tube sheet is welded to the channel, eliminating the need to install a tube sheet gasket, and thus there are no bolts in the inner row. Further, it should be understood that the embodiments shown can be utilized with various prior art methods for achieving internal sealing.

[0065] It should be understood that the above-described arrangement configurations are merely illustrative of the application of the principles of the embodiments shown. Numerous modifications and alternative arrangements can be devised by those skilled in the art without departing from the scope of the embodiments shown, and the appended claims are intended to cover such modifications and arrangements.

Claims

1. A process for assembling a tube heat exchanger assembly, comprising: providing an elongated heat exchanger enclosure having an internal chamber and an open cylindrical channel end, the elongated heat exchanger enclosure defining a longitudinal axis; providing a closure assembly having a lock assembly configured to be fixed to the open cylindrical channel end of the elongated heat exchanger enclosure, the lock assembly comprising: a cylindrical lock ring member defining a cylindrical outer surface portion and a cylindrical inner portion, the cylindrical outer surface portion having a plurality of spaced lock ring hub sections circumferentially separated by non-hub sections around the cylindrical lock ring member, the plurality of spaced lock ring hub sections being configured to interfit with corresponding channel hub sections formed on the cylindrical inner surface portion of the elongated heat exchanger enclosure, and a cylindrical cover member concentrically fixed to the cylindrical inner portion of the cylindrical lock ring member; inserting the lock assembly of the closure assembly axially into the open cylindrical channel end along the longitudinal axis of the internal chamber of the heat exchanger enclosure, such that the plurality of spaced lock ring hub sections of the cylindrical lock ring member do not contact the corresponding channel hub sections formed on the cylindrical inner surface portion of the elongated heat exchanger enclosure; rotating the lock assembly less than 360 degrees relative to the elongated heat exchanger enclosure about the longitudinal axis of the elongated heat exchanger enclosure, such that the plurality of spaced lock ring hub sections on the cylindrical lock member interfit with the corresponding channel hub sections on the elongated heat exchanger enclosure, thereby removably fixing the lock assembly to the elongated heat exchanger enclosure and transmitting a load between the closure assembly and the elongated heat exchanger enclosure. ​ A process including

2. The process for assembling a tube heat exchanger according to claim 1, wherein the lock assembly of the closure assembly and the elongated heat exchanger enclosure cooperatively form a bayonet lock assembly.

3. Before inserting the lock assembly, Axially inserting a tube sheet gasket into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to a channel shoulder within the elongated heat exchanger enclosure; Axially inserting a tube sheet into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the tube sheet gasket, thereby defining a shell side and a channel side within the internal chamber of the elongated heat exchanger enclosure, wherein the internal chamber is configured to removably receive a tube bundle disposed within the shell side of the internal chamber; Axially inserting a sleeve member into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the tube sheet; Axially inserting an elastic torsion member into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the sleeve member; Axially inserting a bearing ring into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the elastic torsion member; Axially inserting a diaphragm into the open cylindrical channel end along the longitudinal axis of the elongated heat exchanger enclosure so as to be disposed adjacent to the bearing ring The process for assembling a tube heat exchanger according to claim 2, further including

4. Adjusting a plurality of first elongate outer compression members provided along an outer diameter portion of the closure assembly that extends coaxially within the closure assembly along the longitudinal axis of the closure assembly, thereby transmitting a first force to a first compression ring, thereby transmitting the first force to a rim portion of the diaphragm and a diaphragm gasket, thereby pressing the diaphragm gasket against the diaphragm; Adjusting a plurality of second elongate inner compression members provided along an inner diameter portion of the closure assembly that extends coaxially within the closure assembly along the longitudinal axis of the closure assembly, thereby transmitting a second force to a second compression ring, thereby transmitting the second force to a portion of the diaphragm when the closure assembly is fixed relative to the elongate heat exchanger enclosure, deflecting a portion of the diaphragm distally away from the closure assembly toward the elastic torsional member of the heat exchanger assembly; The process for assembling a tube heat exchanger according to claim 3, further comprising.

5. The tube sheet, the sleeve member, the first and second compression rings, the closure assembly, the plurality of first elongate outer compression members, and the plurality of second elongate inner compression members are configured to maintain elasticity up to and including a total axial load from preload, thermal load, and pressure load when the closure assembly is fixed relative to the heat exchanger enclosure. The process for assembling a tube heat exchanger according to claim 4.

6. When the plurality of first elongate outer compression members and the plurality of second elongate inner compression members are subjected to a preload, the plurality of first elongate outer compression members and the plurality of second elongate inner compression members apply the preload to a first contact area of the elastic torsional member through a first axial load path, thereby transmitting the preload to a second contact area of the elastic torsional member through a torsional load path through the elastic torsional member, thereby transmitting the preload to a tube sheet gasket through a second axial load path. The process for assembling a tube heat exchanger according to claim 5.

7. The process for assembling a tube heat exchanger according to claim 6, wherein the torsional load is resisted by an increase in stress and torsional rotation of the elastic torsion member, whereby the first contact area of the elastic torsion member can move towards the diaphragm, and the second contact area of the elastic torsion member can move towards the tube sheet.

8. A closure assembly configured to be removably fixed to an open channel end of an internal chamber of a heat exchanger assembly, comprising: A cylindrical lock ring member defining a cylindrical outer surface portion and a cylindrical inner portion, the cylindrical outer surface portion having a plurality of spaced lock ring hub sections circumferentially separated by a non-hub section around the cylindrical lock ring member, the plurality of spaced lock ring hub sections being configured to interfit with corresponding channel hub sections formed on a cylindrical inner surface portion of the heat exchanger assembly; A cylindrical cover member concentrically fixed to the cylindrical inner portion of the cylindrical lock ring member; having; The plurality of spaced lock ring hub sections are configured to interfit with the corresponding channel hub sections by rotating the cylindrical lock ring member less than 360 degrees relative to the open channel end of the heat exchanger assembly, thereby fixing the cylindrical lock ring member to the heat exchanger assembly.

9. The closure assembly according to claim 8, wherein the cylindrical cover member is removably fixed to the cylindrical lock ring member, the cylindrical lock ring member having an inner surface with a shoulder configured to receive a cooperating shoulder provided on an outer surface of the cylindrical cover member.

10. Each lock ring hub section extends at a predetermined angle from the cylindrical outer surface portion of the cylindrical lock ring member and is configured to interfit with a corresponding angled hub section provided in each channel hub section formed on the cylindrical inner surface portion of the heat exchanger assembly. The closure assembly according to claim 8.

11. The closure assembly according to claim 8, further comprising a rail provided on the cylindrical lock ring member, the rail closing one side of a corresponding one of the plurality of spaced lock ring hub sections, thereby preventing excessive rotation of the closure assembly into the internal chamber of the heat exchanger assembly.

12. The closure assembly according to claim 8, further comprising a diaphragm configured to be disposed adjacent to the cylindrical lock ring member and the cylindrical cover member.

13. A plurality of adjustable elongated outer lock ring compression members removably fixable within the cylindrical lock ring member, each adjustable elongated outer lock ring compression member passing through a respective hole formed coaxially with the longitudinal axis within the cylindrical lock ring member, thereby transmitting a force to a first compression ring, the first compression ring transmitting the force to a rim portion of the diaphragm; A diaphragm gasket pressed against the diaphragm, whereby when the cylindrical lock ring member is removably fixed to the internal chamber of the heat exchanger assembly, the diaphragm is disposed intermediate the diaphragm gasket and the first compression ring by adjusting the adjustable elongated outer lock ring compression members. The closure assembly according to claim 12, further comprising a diaphragm gasket.

14. A closure assembly configured to be removably fixed to an open channel end of an internal chamber of a heat exchanger assembly, comprising: A cylindrical lock ring member defining a cylindrical outer surface portion and an inner portion of cylindrical shape, wherein the cylindrical outer surface portion comprises a plurality of spaced lock ring hub sections configured to interfit with corresponding channel hub sections formed on an inner surface portion of the cylindrical shape of the heat exchanger assembly; A cylindrical cover member concentrically fixed to the inner cylindrical portion of the cylindrical lock ring member; A diaphragm configured to be disposed adjacent to the cylindrical lock ring member and the cylindrical cover member; A plurality of adjustable elongate outer lock ring compression members removably fixable within the cylindrical lock ring member, each adjustable elongate outer lock ring compression member passing through a respective hole formed coaxially with the longitudinal axis within the cylindrical lock ring member, thereby transmitting a force to a first compression ring, the first compression ring transmitting the force to a rim portion of the diaphragm; A diaphragm gasket pressed against the diaphragm such that when the cylindrical lock ring member is removably fixed to the internal chamber of the heat exchanger assembly, adjustment of the adjustable elongate outer lock ring compression members disposes the diaphragm intermediate the diaphragm gasket and the first compression ring; A plurality of adjustable elongate inner cover compression members removably fixable within the cylindrical-shaped cover member, each adjustable elongate inner cover compression member passing through a respective hole formed coaxially with the longitudinal axis within the cylindrical-shaped cover member when the closure assembly is removably fixed to the open channel end of the internal chamber of the heat exchanger assembly, thereby transmitting a force to a second compression ring, the second compression ring transmitting the force to a portion of the diaphragm, thereby deflecting a portion of the diaphragm distally from the cylindrical-shaped cover member towards the internal chamber of the heat exchanger assembly, and a plurality of adjustable elongate inner cover compression members A closure assembly having the same. **Claim 15** The closure assembly according to claim 14, wherein when the closure assembly is removably fixed to the open channel end of the internal chamber of the heat exchanger assembly, the first and second compression rings, the plurality of adjustable elongate outer lock ring compression members, and the plurality of adjustable elongate inner cover compression members are configured to maintain elasticity up to and including a total axial load from preload, thermal load, and pressure load. **Claim 16** The closure assembly according to claim 8, wherein the cylindrical outer surface portion of the cylindrical-shaped lock ring member comprises a groove formed substantially perpendicular to the longitudinal axis of the cylindrical-shaped lock ring member, the groove being configured to be slidably received within a corresponding notch formed within the inner surface portion of the heat exchanger assembly perpendicular to the longitudinal axis of the cylindrical-shaped lock ring member, thereby facilitating insertion of the cylindrical-shaped lock ring member into the inner surface portion of the heat exchanger assembly. **Claim 17** The closure assembly according to claim 14, wherein the plurality of spaced lock ring hub sections are configured to interfit with the corresponding channel hub sections by rotating the cylindrical-shaped lock ring member less than 360 degrees relative to the open channel end of the heat exchanger assembly, thereby fixing the cylindrical-shaped lock ring member to the heat exchanger assembly. **Claim 18** A process for assembling a tube heat exchanger assembly comprising: providing an elongate heat exchanger enclosure having an internal chamber, defining a longitudinal axis, and having open cylindrical channel ends; providing a closure assembly having a lock assembly configured to be fixed to the open cylindrical channel ends of the elongate heat exchanger enclosure; axially inserting the lock assembly of the closure assembly into the open cylindrical channel ends along the longitudinal axis of the internal chamber of the heat exchanger such that load-bearing surfaces of each of the closure assembly and the inner wall of the elongate heat exchanger enclosure do not contact each other; rotating the closure assembly less than 360 degrees relative to the elongate heat exchanger enclosure about the longitudinal axis of the elongate heat exchanger enclosure such that the lock assembly is removably fixed to a cooperating lock assembly provided on the internal wall of the elongate heat exchanger enclosure, whereby the load-bearing surfaces contact each other and a load is transmitted between the closure assembly and the elongate heat exchanger enclosure; comprising wherein the step of rotating the closure assembly comprises mating spaced lock ring hub sections of the closure assembly with corresponding channel hub sections of the cooperating lock assembly of the elongate heat exchanger enclosure.

Images