Patent Description:
A gas turbine system may use one or more heat exchangers to transfer heat between different fluids. For example, the gas turbine system may discharge an exhaust gas flow into a heat recovery steam generator (HRSG), which includes one or more heat exchangers configured to transfer heat from the exhaust gas flow to generate steam. Unfortunately, the exhaust gas flow may apply an oscillating force on the heat exchangers due to oscillations in the exhaust gas flow, thereby causing vibration of the heat exchangers (i.e., a vibratory load). If a frequency of the oscillating force (i.e., an excitation load frequency) is equal to or close to a natural frequency of the heat exchangers, then resonance can occur in the heat exchangers. In turn, the resonance may increase an amplitude of the vibration to unacceptable levels, potentially causing mechanical wear or damage. Accordingly, a need exists for restraining the heat exchangers in a manner adding stiffness to the heat exchangers and detuning the natural frequency of the heat exchangers away from the excitation load frequencies caused by the exhaust gas flow.

Document <CIT> discloses a system for tensioning a flow grating in a duct with a restraint system using a rod in a sleeve for tensioning the grating.

Document <CIT> discloses a system for mitigating vibration in a nuclear powered steam generator using a restraint system comprising a wire in one of the heat exchanger tubes.

Document <CIT> discloses a system for mitigating vibration in a nuclear powered j steam generator using a threaded rod connected to a tensioning bar.

The invention as herein claimed refers to the subject matter set forth in the claims.

In certain embodiments, a system includes a restraint system configured to support a heat exchanger along a flow path within a duct. The restraint system includes a first sleeve configured to extend between opposite first and second walls of the duct, a first cable extending through the first sleeve, and a first bumper coupled to the first sleeve. The first bumper is configured to contact the heat exchanger. The restraint system includes a first tensioner coupled to the first cable, wherein the first tensioner is configured to provide a first tension in the first cable.

In certain embodiments, a method includes supporting a heat exchanger along a flow path within a duct via a restraint system. The restraint system includes a first sleeve configured to extend between opposite first and second walls of the duct, a first cable extending through the first sleeve, and a first bumper coupled to the first sleeve. The first bumper is configured to contact the heat exchanger. The method includes providing a first tension in the first cable via a first tensioner coupled to the first cable.

In certain embodiments, a heat recovery steam generator includes a heat exchanger disposed in a duct; and a restraint system configured to support the heat exchanger along a flow path within the duct. The restraint system includes first and second sleeves configured to extend between opposite first and second walls of the duct, first and second cables extending through the first and second sleeves, respectively, and first and second bumpers coupled to the first and second sleeves, respectively. The first bumper is configured to contact an upstream side of the heat exchanger, and the second bumper is configured to contact a downstream side of the heat exchanger. The system includes a tension system coupled to the first and second cables, wherein the tension system comprises a plurality of tensioners configured to provide a first tension in the first cable and a second tension in the second cable. The first and second tensions are configured to adjust a stiffness of the restraint system and to adjust a natural frequency of the heat exchanger away from an excitation load frequency.

In a variety of applications, one or more heat exchangers may be disposed along a fluid flow path (e.g., an exhaust flow path), such that a fluid flow passes through and/or around the heat exchangers to facilitate heat transfer. Unfortunately, the fluid flow also may subject the heat exchangers to potential vibration due to oscillations in the fluid flow. The disclosed embodiments include a restraint system configured to help retain a position of the heat exchangers along the fluid flow path, while also helping to reduce the possibility of resonance in the heat exchangers. For example, if the fluid flow applies an oscillating force on the heat exchangers, then resonance can occur when a frequency of the oscillating force (i.e., an excitation load frequency) is equal to or close to a natural frequency of the heat exchangers. Accordingly, as discussed in detail below, the restraint system includes a stiffening system and/or vibration damping system having a cable and sleeve assembly and a tensioning assembly, which is configured to enable adjustments to the stiffness of the restraint system and to detune the natural frequencies of the heat exchangers away from the frequency of the oscillating force associated with the fluid flow. The tensioning assembly may include one or more types of tensioners used alone or in combination with one another to vary a tension of cables in the cable and sleeve assembly. Examples of the tensioners may include springs, turnbuckles, fluid-driven tensioners (e.g., piston-cylinder assemblies), electric-driven tensioners, manual tensioners, counter-weight tensioners, or any combination thereof.

<FIG> is a schematic of an embodiment of a system <NUM> having a gas turbine system <NUM>, a heat recovery steam generator (HRSG) <NUM>, a steam turbine system <NUM>, and a restraint system <NUM> configured to provide restraint and vibration damping for various components or modules in the HRSG <NUM>. The vibration damping features of the restraint system <NUM> are adjustable, such that the restraint system <NUM> can be tailored to the operating characteristics of the HRSG <NUM> to reduce the possibility of resonance in the HRSG <NUM>. For example, the HRSG <NUM> may be subject to different frequencies of vibration depending on the operating conditions of the gas turbine system <NUM>. Accordingly, the restraint system <NUM> can adjust a stiffness of the restraint of the components or modules in the HRSG <NUM>, such that a natural frequency of the components or modules can be changed to reduce the possibility of resonance during the various operating conditions. The specific features and operating characteristics of the restraint system <NUM> are discussed in further detail below.

As illustrated, the gas turbine system <NUM> includes an air intake section <NUM>, a compressor section <NUM>, a combustor section <NUM>, a turbine section <NUM>, and a load <NUM>, such as an electrical generator. The air intake section <NUM> may include one or more air filters, anti-icing systems, fluid injection systems (e.g., temperature control fluids), silencer baffles, or any combination thereof. The compressor section <NUM> includes a plurality of stages <NUM> of compressor blades <NUM> (e.g., rotatable blades) and compressor vanes <NUM> (e.g., stationary vanes) disposed within a compressor casing <NUM>. In particular, the compressor blades <NUM> are coupled to a compressor shaft <NUM> and extend radially outward from the shaft <NUM> toward the compressor casing <NUM>, while the compressor vanes <NUM> are coupled to the compressor casing <NUM> and extend radially inward toward the shaft <NUM>. Each of the compressor stages <NUM> may include a plurality of the compressor blades <NUM> arranged circumferentially about the shaft <NUM> and a plurality of the compressor vanes <NUM> arranged circumferentially about the compressor casing <NUM>. The illustrated compressor section <NUM> may include between <NUM> and <NUM> stages <NUM> of the compressor blades <NUM> and the compressor vanes <NUM>.

The combustor section <NUM> includes one or more combustors <NUM>, such as a single annular combustor disposed about a shaft <NUM> between the compressor section <NUM> and the turbine section <NUM>, or a plurality of circumferentially spaced combustors <NUM> disposed about the shaft <NUM>. The one or more combustors <NUM> may include one or more fuel nozzles <NUM>, such as a central fuel nozzle and a plurality of peripheral fuel nozzles (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more peripheral fuel nozzles disposed about the central fuel nozzle). The combustor section <NUM> also may be coupled to one or more fuel supplies <NUM>, such as a liquid fuel supply and/or a gas fuel supply. The fuel supplies <NUM> may include one or more fuel circuits, such as a primary fuel circuit and a secondary fuel circuit, coupled to the fuel nozzles <NUM>. The fuel supplies <NUM> may include fuel sources, such as, but not limited to, natural gas, syngas, biofuel, fuel oils, or any combination of liquid and gas fuels.

The turbine section <NUM> includes a plurality of turbine blades <NUM> (e.g., rotating blades) and a plurality of turbine vanes <NUM> (e.g., stationary vanes) disposed within a turbine casing <NUM> about a turbine shaft <NUM>. Additionally, the turbine blades <NUM> and the turbine vanes <NUM> may be arranged in one or more turbine stages <NUM>, such as between <NUM> and <NUM> or more turbine stages. The turbine blades <NUM> extend radially outward from the shaft <NUM> toward the turbine casing <NUM>, while the turbine vanes <NUM> extend radially inward from the turbine casing <NUM> toward the shaft <NUM>. In each of the turbine stages <NUM>, a plurality of the turbine blades <NUM> are spaced circumferentially around and coupled to the shaft <NUM>, and a plurality of the turbine vanes <NUM> are arranged circumferentially about the turbine casing <NUM>. The turbine shaft <NUM> also connects to the load <NUM> via a shaft <NUM>.

In operation, the gas turbine system <NUM> routes an air intake flow <NUM> from the air intake section <NUM> into the compressor section <NUM>. The compressor section <NUM> progressively compresses the air intake flow <NUM> in the stages <NUM> and delivers a compressed airflow <NUM> into the one or more combustors <NUM>. The one or more combustors <NUM> receive fuel from the fuel supply <NUM>, route the fuel through the fuel nozzles <NUM>, and combust the fuel with the compressed airflow <NUM> to generate hot combustion gasses in a combustion chamber <NUM> within the combustor <NUM>. The one or more combustors <NUM> then route a hot combustion gas flow <NUM> into the turbine section <NUM>. The turbine section <NUM> progressively expands the hot combustion gas flow <NUM> and drives rotation of the turbine blades <NUM> in the stages <NUM> before discharging an exhaust gas flow <NUM>. As the hot combustion gas flow <NUM> drives rotation of the turbine blades <NUM>, the turbine blades <NUM> drive rotation of the turbine shaft <NUM>, the shafts <NUM> and <NUM>, and the compressor shaft <NUM>. Accordingly, the turbine section <NUM> drives rotation of the compressor section <NUM> and the load <NUM>. The exhaust gas flow <NUM> may be partially or entirely directed to flow through the HRSG <NUM> to enable heat recovery and steam generation.

The HRSG <NUM> may include a plurality of modules or components <NUM> disposed along a flow path <NUM> within a duct <NUM> at one or more positions or stages <NUM>. The components <NUM> may include various HRSG equipment configured to recover heat from the exhaust gas flow <NUM>. For example, at each of the stages <NUM>, the components <NUM> may include one or more heat exchangers <NUM>. For example, in the illustrated embodiment, each of the stages <NUM> includes a plurality of heat exchange sections or heat exchangers <NUM>, such as three heat exchangers <NUM>. Additionally, the HRSG <NUM> may include the restraint system <NUM> in one or more of the stages <NUM>. For example, in certain embodiments, the HRSG <NUM> may include the restraint system <NUM> only at the first stage <NUM>, while some embodiments of the HRSG <NUM> may include the restraint system <NUM> in <NUM>, <NUM>, <NUM>, <NUM>, or more stages <NUM> (e.g., all of the stages). As discussed in further detail below, the restraint system <NUM> may include a stiffening system and/or vibration damping system <NUM> configured to help stiffen the restraint system <NUM> and to reduce vibration and detune the natural frequencies of the components <NUM> away from excitation load frequencies, thereby reducing the possibility of resonance in the components <NUM> of the HRSG <NUM>.

The vibration damping system <NUM> of the restraint system <NUM> may include a cable and sleeve assembly <NUM> configured to enable adjustment of the stiffness of the restraint system <NUM>, such that tuning is possible to reduce the possibility of any resonance in the HRSG <NUM>. The cable and sleeve assembly <NUM> may extend across the duct <NUM> in a horizontal orientation, a vertical orientation, or an angular orientation (e.g., at an angle between horizontal and vertical orientations). The cable and sleeve assembly <NUM> may include one or more cables <NUM> disposed in each of one or more sleeves <NUM>. Accordingly, each sleeve <NUM> with one or more cables <NUM> therein may extend across the duct <NUM> in the horizontal, vertical, or angular orientation. In embodiments having a plurality of sets of sleeves <NUM> with one or more cables <NUM> therein, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more (e.g., part or all) of the plurality of sets of sleeves <NUM> and cables <NUM> may be disposed in the horizontal orientation, the vertical orientation, the angular orientation, or a combination thereof. In each orientation (e.g., horizontal, vertical, or angular), a plurality of the sets of sleeves <NUM> with one or more cables therein may be spaced apart from one another in different positions, such as a spaced parallel arrangement. In the present embodiment, all of the plurality of sets of sleeves <NUM> with one or more cables <NUM> are disposed in the horizontal orientation at one or more vertical heights or elevations, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or more vertical heights or elevations.

Additionally, the cable and sleeve assembly <NUM> may include one or more upstream cable and sleeve assemblies <NUM> and one or more downstream cable and sleeve assemblies <NUM> relative to a direction of the exhaust gas flow <NUM> along the flow path <NUM>. For example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more upstream cable and sleeve assemblies <NUM> may include the sleeves <NUM> with cables <NUM> in the same or different orientations (e.g., horizontal, vertical, or angular orientations). By further example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more downstream cable and sleeve assemblies <NUM> may include the sleeves <NUM> with cables <NUM> in the same or different orientations (e.g., horizontal, vertical, or angular orientations). In embodiments with the same orientation, the sleeves <NUM> with cables <NUM> in the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> may be parallel to one another. In embodiments with different orientations, the sleeves <NUM> with cables <NUM> in the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> may be crosswise (e.g., perpendicular) to one another. However, as noted above in the present embodiment, all of the plurality of sets of sleeves <NUM> with one or more cables <NUM> are disposed in the horizontal orientation, and thus the sleeves <NUM> with cables <NUM> may be parallel to one another across the duct <NUM>. Additionally, each of the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> may include a plurality of sets of sleeves <NUM> with one or more cables <NUM> spaced apart from one another (e.g., uniformly or non-uniformly spaced) in the horizontal orientation at different vertical heights or elevations, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more vertical heights or elevations.

In each of the cable and sleeve assemblies <NUM>, one or more cables <NUM> extend through each sleeve <NUM> between opposite duct walls <NUM> and <NUM> of the duct <NUM>. The sleeves <NUM> extend between and couple to the opposite duct walls <NUM> and <NUM>, and the cables <NUM> extend outside of the opposite duct walls <NUM> and <NUM> and couple with a tension assembly <NUM>. The opposite duct walls <NUM> and <NUM> may be opposite side walls connected to one another by opposite top and bottom walls, or the opposite duct walls <NUM> and <NUM> may be opposite top and bottom walls connected to one another by opposite side walls. In the illustrated embodiment, the opposite duct walls <NUM> and <NUM> may be opposite side walls, each illustrated sleeve <NUM> and cable <NUM> extends in the horizontal orientation, and each illustrated sleeve <NUM> and cable <NUM> represents a plurality of vertically spaced, parallel sets of the sleeves <NUM> and cables <NUM> across the duct <NUM> between the top and bottom walls.

The sleeves <NUM> (e.g., protective sleeves) are configured to protect the cables <NUM> from exposure to the exhaust gas flow <NUM> in the duct <NUM>. For example, the sleeves <NUM> may provide thermal protection, wear resistance, erosion resistance, chemical resistance, or any combination thereof. In certain embodiments, the sleeves <NUM> may include a hollow annular body and/or a surface coating comprising a thermally insulative material, a wear resistant material, an erosion resistant material, a chemically resistant material, or any combination thereof. For example, the sleeves <NUM> may be constructed with a stainless steel material. The sleeves <NUM> may completely surround the cables <NUM> and seal with the duct <NUM>, such that the exhaust gas flow <NUM> is substantially or completely blocked from entering the sleeves <NUM> and contacting the cables <NUM>. The cables <NUM> may be constructed from the same or different materials than the sleeves <NUM>. In certain embodiments, for example, the cables <NUM> may be constructed from a stainless steel material, which is the same as or different from the stainless steel material of the sleeves <NUM>.

The dimensions of the sleeves <NUM> and the cables <NUM> may be selected to provide sufficient restraint for the components <NUM> of the HRSG <NUM>. In certain embodiments, a diameter of the sleeves <NUM> is between approximately <NUM> to <NUM> centimeters, <NUM> to <NUM> centimeters, or about <NUM> centimeters. The diameter of the cables <NUM> may vary based on the number of cables <NUM> inside each sleeve <NUM> and the diameter of the sleeve <NUM>. For example, each sleeve <NUM> may include <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> cables <NUM>, wherein each cable <NUM> has a diameter of approximately <NUM> to <NUM> centimeters or <NUM> to <NUM> centimeters. In certain embodiments, each sleeve <NUM> may be approximately <NUM> centimeters in diameter, each sleeve <NUM> may include <NUM> or <NUM> cables <NUM>, and each cable <NUM> may be approximately <NUM> to <NUM> centimeters in diameter. The cables <NUM> are flexible and respond to tension to vary a stiffness of the cables <NUM> and the sleeves <NUM> across the duct <NUM> at the upstream and downstream sides of the components <NUM>.

The tension assembly <NUM> may include one or more tensioners <NUM> coupled to each of the one or more cables <NUM>. The tensioners <NUM> are configured to adjust the tension in each of the cables <NUM>, thereby allowing adjustment of the stiffness of the upstream and downstream cable and sleeve assemblies <NUM>, which provide restraint against movement of the components <NUM> in each of the one or more stages <NUM>. Accordingly, by increasing or decreasing tension via the tensioners <NUM>, the stiffness of the restraint of the components <NUM> may be adjusted to detune the natural frequencies of the components <NUM> away from the excitation load frequencies caused by oscillations of the exhaust gas flow <NUM> through the duct <NUM>. The tensioners <NUM> and/or the cables <NUM> may be coupled to a support structure <NUM> disposed on the outer surfaces of each of the duct walls <NUM> and <NUM>. As discussed in further detail below, each of the tensioners <NUM> may include one or more spring tensioners, turnbuckles, fluid-driven tensioners, electric-driven tensioners, manual tensioners, counter-weight tensioners, or any combination thereof.

The exhaust gas flow <NUM> flows through the duct <NUM> and transfers heat to one or more fluids in the components <NUM> (e.g., heat exchangers <NUM>), which may be configured to generate steam for the steam turbine system <NUM>. The components <NUM> of the HRSG <NUM> may include a low pressure (LP) section of the components <NUM>, an intermediate pressure (IP) section of the components <NUM>, and a high pressure (HP) section of the components <NUM>. The components <NUM> (e.g., heat exchangers <NUM>) may include economizers, evaporators, superheaters, or any combination thereof, in each of the LP, IP, and HP sections. For example, the heat exchangers <NUM> of the components <NUM> may include low pressure heat exchangers, high pressure heat exchangers, intermediate heat exchangers, or any combination thereof. The heat exchangers <NUM> may be coupled together via various conduits and headers, and the HRSG <NUM> may route one or more flows of steam <NUM> (e.g., low pressure steam, intermediate pressure steam, and high pressure steam) to a steam turbine <NUM> of the steam turbine system <NUM>.

The steam turbine <NUM> may include a high pressure steam turbine (HP ST) <NUM>, an intermediate pressure steam turbine (IP ST) <NUM>, and a low pressure steam turbine (LP ST) <NUM>, which are coupled together via shafts <NUM> and <NUM>. Additionally, the steam turbine <NUM> may be coupled to a load <NUM> via a shaft <NUM>. Similar to the load <NUM>, the load <NUM> may include an electrical generator. The HRSG <NUM> may be configured to generate a high pressure steam for the high pressure steam turbine <NUM>, an intermediate pressure steam for the intermediate pressure steam turbine <NUM>, and a low pressure steam for the low pressure steam turbine <NUM>. The steam turbine <NUM> may discharge a condensate <NUM> (or the steam may be condensed downstream from the steam turbine <NUM>), such that the condensate <NUM> can be pumped back into the HRSG <NUM> via one or more pumps <NUM>.

Again, as discussed in further detail below, the restraint system <NUM> is configured to restrain movement of the components <NUM>, such as the heat exchangers <NUM>, and to control vibration via the vibration damping system <NUM>. The illustrated system <NUM> also includes a controller <NUM> configured to control operation of the gas turbine system <NUM>, the HRSG <NUM>, the steam turbine system <NUM>, and one or more features of the vibration damping system <NUM>. The controller <NUM> includes one or more processors <NUM>, memory <NUM>, and instructions <NUM> stored on the memory <NUM> and executable by the processor <NUM>. For example, the instructions <NUM> may include gas turbine operating instructions, HRSG operating instructions, steam turbine operating instructions, and vibration damping instructions for the vibration damping system <NUM>. The controller <NUM> also may receive feedback from a plurality of sensors <NUM>, which are designated by an "S" in <FIG>, and perform control actions (e.g., alerts, alarms, and/or adjustments of operating parameters) in response to the feedback. The sensors <NUM> may be communicatively coupled to the controller <NUM> via wires or wireless communication circuity.

The sensors <NUM> may be disposed at one or more locations in the air intake section <NUM>, the compressor section <NUM>, the combustor section <NUM>, the turbine section <NUM>, the HRSG <NUM>, and the steam turbine system <NUM>. In particular, the sensors <NUM> may be disposed at various locations throughout the HRSG <NUM>, such that vibration, oscillations in the exhaust gas flow <NUM>, and other flow characteristics may be measured along the flow path <NUM>. For example, the sensors <NUM> may include flow sensors, vibration sensors, pressure sensors, temperature sensors, fuel composition sensors, exhaust emissions sensors (e.g., nitrogen oxide sensors, carbon monoxide sensors, or carbon dioxide sensors), or any combination thereof. The flow sensors may measure the flow rate of the exhaust gas flow <NUM> and help identify oscillations in the flow rate. The vibration sensors may measure vibration in the duct <NUM>, the components <NUM>, the restraint system <NUM>, or any combination thereof. The pressure sensors may measure the pressure of the exhaust gas flow <NUM> and help identify oscillations in the pressure. The temperature sensors may measure the temperature of the exhaust gas flow <NUM> and help identify oscillations in the temperature. The foregoing sensors <NUM> also may be used to measure similar oscillations in the compressor section <NUM>, the combustor section <NUM>, and the turbine section <NUM>. The feedback from the sensors <NUM> may be used by the controller <NUM> in a variety of ways.

In certain embodiments, if the controller <NUM> observes undesirable sensor feedback within the HRSG <NUM> or at the components <NUM>, then the controller <NUM> may provide an alarm or an alert to a user via an electronic display, change operation of the system <NUM>, or make adjustments to the vibration damping system <NUM> depending on the type of tensioners <NUM> used within the restraint system <NUM>. The undesirable sensor feedback may include any of the foregoing sensor feedback exceeding one or more thresholds, rising or falling at an excessive rate, meeting or approaching a level known to be associated with resonance, or any combination thereof. As a non-limiting example, the undesirable sensor feedback from the sensors <NUM> may include a vibration exceeding one or more vibration thresholds, wherein a first vibration threshold may trigger an alert (e.g., a visual alert on the electronic display), a second vibration threshold may trigger an alarm (e.g., an audible alarm through a speaker), a third vibration threshold may trigger a first control action (e.g., a first corrective action to help reduce the vibration), and a fourth vibration threshold may trigger a second control action (e.g., a second corrective action to help reduce the vibration).

The corrective actions may be automatic control actions by the controller <NUM> and/or controller <NUM> recommended adjustments that prompt user intervention. The corrective actions may include adjustments to the gas turbine system <NUM>, such as changes in the fuel supply, changes in the fuel/air ratio, and/or changes in the exhaust gas flow <NUM>. In certain applications, the corrective actions may include shutting down the gas turbine system <NUM> and/or diverting the exhaust gas flow <NUM> away from the HRSG <NUM>. The corrective actions also may include adjustments to the vibration damping system <NUM> (e.g., tensioners <NUM>). For example, if the vibration damping system <NUM> includes tensioners <NUM> having electronic control features, then the controller <NUM> may automatically adjust the tensioners <NUM> to change the tension in the cables <NUM> and thus change the stiffness of the restraint system <NUM>. In this manner, the adjusted tension in the cables <NUM> and stiffness in the restraint system <NUM> can detune the natural frequencies of the components <NUM> (e.g., heat exchangers <NUM>) away from the excitation load frequencies in the components <NUM>, thereby helping to reduce the possibility of resonance in the components <NUM>. In certain embodiments, one or more of the tensioners <NUM> may be adjusted manually by a technician, rather than automatically by the controller <NUM>, and thus the corrective actions prompt user intervention. Additionally, one or more of the tensioners <NUM> may not be adjustable; however, the non-adjustable tensioners <NUM> may be used in combination with one or more adjustable tensioners <NUM>. Examples and characteristics of the tensioners <NUM> are described in further detail below.

<FIG> is a partial schematic view of an embodiment of the HRSG <NUM> of <FIG>, illustrating the restraint system <NUM> having the vibration damping system <NUM> at one of the stages <NUM> of the HRSG <NUM>. The vibration damping system <NUM> includes the cable and sleeve assembly <NUM> coupled to the tension assembly <NUM>, which facilitates adjustment of the tension in each cable <NUM> in a respective sleeve <NUM> in both the upstream and downstream cable and sleeve assemblies <NUM> and <NUM>. The cable and sleeve assemblies <NUM> are illustrated with only one sleeve <NUM> and corresponding cable <NUM> at each of the upstream and downstream cable and sleeve assemblies <NUM> and <NUM>. However, each of the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> may include a plurality of sleeves <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more sleeves) having one or more corresponding cables <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more cables per sleeve) coupled to tensioners <NUM> to facilitate restraint and vibration damping of the heat exchangers <NUM> of the components <NUM>.

In certain embodiments, one or more cables <NUM> may include a common cable <NUM> (e.g., a single cable or a plurality of cables in a bundle) extending sequentially through a plurality of sleeves <NUM> in series, such that the common cable <NUM> has a first cable or cable portion 84A disposed in a first sleeve 86A and a second cable or cable portion 84B disposed in a second sleeve 86B, wherein the common cable <NUM> extends a distance between the sleeves 86A and 86B via an intermediate cable or cable portion 86C outside of the sleeves 86A and 86B. The cables or cable portions 84A, 84B, and 84C may be integrally formed as a single continuous cable or the cables or cable portions 84A, 84B, and 84C may be fixedly or removably connected together via joints, such as welded joints, hooks, removable fasteners, or any combination thereof. The common cable <NUM> may extend between the sleeves 86A and 86B via a sleeve, a channel, a conduit, a plurality of cable hooks, a plurality of cable loops, or any combination thereof. In certain embodiments, the common cable <NUM> may extend through and/or couple to the tensioners <NUM> for associated with the different sleeves <NUM>, e.g., sleeves 86A and 86B. Additionally, in certain embodiments, the common cable <NUM> may be coupled to a single shared tensioner <NUM> at one or both sides of the duct <NUM>.

In the illustrated embodiment, each of the sleeves <NUM> of the cable and sleeve assemblies <NUM> includes a central sleeve portion <NUM> disposed between opposite end sleeve portions <NUM>. The central sleeve portion <NUM> is disposed within the flow path <NUM> inside the duct <NUM> between the opposite duct walls <NUM> and <NUM>, such that the central sleeve portion <NUM> is exposed to the exhaust gas flow <NUM> along the flow path <NUM>. The end sleeve portions <NUM> extend through and seal with the opposite duct walls <NUM> and <NUM>. The end sleeve portions <NUM> may protrude outwardly from the opposite duct walls <NUM> and <NUM>, or the end sleeve portions <NUM> may terminate and seal flush with the opposite duct walls <NUM> and <NUM>. For example, the end sleeve portions <NUM> are disposed in bores <NUM> and <NUM> in the respective duct walls <NUM> and <NUM>. The end sleeve portions <NUM> extend outward away from the duct walls <NUM> and <NUM> and couple to expansion bellows <NUM> (e.g., annular expansion bellows).

Each expansion bellows <NUM> includes an annular body <NUM> disposed about the end sleeve portion <NUM> at each of the duct walls <NUM> and <NUM>, and an annular flange or lip <NUM> extending radially outward from the annular body <NUM> of the expansion bellows <NUM>. The expansion bellows <NUM> also includes a bore <NUM> disposed about the end sleeve portion <NUM> of the sleeve <NUM>. The annular body <NUM> has a bellows wall <NUM> having a diameter that increases and decreases in an alternating manner between first and second diameters, wherein the first diameter is larger than the second diameter. For example, the bellows wall <NUM> has a plurality of annular wall sections that are angled between the first and second diameters, such that the plurality of annular wall sections can expand and contract in an axial direction along a central axis of the expansion bellows <NUM>. The expansion bellows <NUM> is configured to enable expansion and contraction (e.g., thermal expansion and contraction) of the sleeve <NUM> during operation of the HRSG <NUM> while maintaining a seal of the sleeve <NUM> with the opposite duct walls <NUM> and <NUM> of the duct <NUM>.

The annular lip <NUM> of the expansion bellows <NUM> may be coupled to the outer surface of each of the duct walls <NUM> and <NUM> via a fastener or joint <NUM> (e.g., a brazed joint and/or a welded joint), which is configured to fix and seal the expansion bellows <NUM> to the duct <NUM>. In some embodiments, the annular lip <NUM> of the expansion bellows <NUM> may be coupled to the duct walls <NUM> and <NUM> with one or more removable fasteners (e.g., threaded fasteners or bolts), threaded connections, clamps, or other removable or fixed fasteners. The expansion bellows <NUM> also may include one or more seals (e.g., annular seals) between the annular lip <NUM> and the duct <NUM> and/or between the annular body <NUM> and the end sleeve portion <NUM>.

The end sleeve portion <NUM> may be coupled to the expansion bellows <NUM> via a retainer <NUM>. In certain embodiments, the retainer <NUM> may be a brazed joint and/or a welded j oint, which is configured to fix and seal the end sleeve portion <NUM> to the expansion bellows <NUM>. In some embodiments, the retainer <NUM> may include an annular clip (e.g., a C-clip) disposed in an annular slot on the end sleeve portion <NUM>, an annular nut threaded onto a threaded annular portion of the end sleeve portion <NUM>, an annular flange (e.g., welded to the end sleeve portion <NUM> and bolted to the expansion bellows <NUM>), or another removable or fixed retainer. Accordingly, the sleeve <NUM> of each of the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> is coupled to both the duct wall <NUM> and the duct wall <NUM> via the expansion bellows <NUM> at the end sleeve portions <NUM> of the sleeve <NUM>.

During operation, the expansion bellows <NUM> are configured to enable expansion and contraction of the sleeves <NUM> while also sealing the expansion bellows <NUM> to the opposite duct walls <NUM> and <NUM>, thereby blocking entry of the exhaust gas flow <NUM> within the flow path <NUM> into the sleeves <NUM> or outside of the duct <NUM>. Thus, the expansion bellows <NUM> help to protect the cables <NUM> disposed inside of the sleeves <NUM> and immediately outside of the duct <NUM>.

The components <NUM>, which include one or more heat exchangers <NUM>, are retained between the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> of the vibration damping system <NUM> of the restraint system <NUM>. As illustrated, the restraint system <NUM> includes a bumper assembly <NUM> having a plurality of bumpers <NUM> coupled to each of the sleeves <NUM> and contacting upstream and downstream sides <NUM> and <NUM> of the heat exchangers <NUM>. Each of the bumpers <NUM> includes a bumper head <NUM> coupled to a support bracket or arm <NUM>. The bumper head <NUM> is configured to contact the heat exchanger <NUM> at the upstream side <NUM> or the downstream side <NUM>. The support bracket or arm <NUM> is coupled to the sleeve <NUM> in the upstream or downstream cable and sleeve assembly <NUM> and <NUM> via one or more fasteners as discussed below. In the illustrated embodiment, each of the heat exchangers <NUM> of the component <NUM> may include one or more of the bumpers <NUM> at both the upstream side <NUM> and the downstream side <NUM> of the respective heat exchanger <NUM>.

Additionally, each of the heat exchangers <NUM> may include one or more tubes <NUM> supported by a heat exchanger body or framework <NUM>, which is configured to help hold together the one or more tubes <NUM>. The tubes <NUM> are configured to circulate a fluid (e.g., water) configured to be heated by the exhaust gas flow <NUM> along the flow path <NUM> in the duct <NUM>. The bumpers <NUM> may be configured to contact the one or more tubes <NUM>, the body or framework <NUM>, or a combination thereof. As discussed in further detail below, the tension assembly <NUM> is configured to adjust the tension in the one or more cables <NUM> in each of the one or more sleeves <NUM>, thereby adjusting the stiffness of the cable and sleeve assemblies <NUM> while the bumpers <NUM> contact the heat exchangers <NUM> to detune the natural frequencies of the heat exchangers <NUM> away from the excitation load frequencies (e.g., frequencies of loads on the heat exchangers <NUM> due to the frequencies of oscillations in the exhaust gas flow <NUM>).

The cable and sleeve assembly <NUM> has one or more cables <NUM> extending through each sleeve <NUM> in the upstream and downstream cable and sleeve assemblies <NUM> and <NUM>. The cables <NUM> are coupled to one or more tensioners <NUM> of the tension assembly <NUM>. In the illustrated embodiment, each cable <NUM> is coupled to one or more tensioners <NUM> on opposite sides of the duct <NUM> at the opposite duct walls <NUM> and <NUM>. The tensioners <NUM> are coupled to the support structure <NUM> via a mount <NUM>. In certain embodiments, the mount <NUM> may include a mounting arm, a bracket, a cable, a flange, or any combination thereof. In some embodiments, the tension assembly <NUM> may include one or more tensioners <NUM> disposed at only one side of the duct <NUM>, such as only at the duct wall <NUM> for all or part of the sleeves <NUM>, only at the duct wall <NUM> for all or part of the sleeves <NUM>, or only one side of the duct <NUM> for each of the sleeves <NUM>. However, in the illustrated embodiment, the tensioners <NUM> are disposed on both sides of the duct <NUM> for each of the sleeves <NUM> at both the upstream and downstream cable and sleeve assemblies <NUM> and <NUM>.

As discussed in further detail below, the illustrated tensioners <NUM> may include one or more types of tensioners being used alone or in combination with one another to adjust the tension in each of the cables <NUM>. By adjusting the tension in the cables <NUM> at the upstream and downstream cable and sleeve assemblies <NUM> and <NUM>, the stiffness of the restraint system <NUM> can be increased or decreased, thereby helping to detune the natural frequencies of the heat exchangers <NUM> away from the excitation load frequencies within the HRSG <NUM>.

The support structure <NUM> includes a U-shaped body <NUM> disposed at each of the duct walls <NUM> and <NUM> and extending from the outer surface of the respective duct walls <NUM> and <NUM>. The U-shaped body <NUM> includes extension arms or beams <NUM> and <NUM> disposed respectively upstream and downstream of the stage <NUM>, and a mounting support or plate <NUM> coupling together the extension arms or beams <NUM> and <NUM>. The extension arms or beams <NUM> and <NUM> may have an I-shaped structure or H-shaped structure or some other configuration to support the mounting support or plate <NUM> at each of the duct walls <NUM> and <NUM>. The extension arms or beams <NUM> and <NUM> are coupled to each of the duct walls <NUM> and <NUM> via one or more joints <NUM>, such as welded joints and/or brazed joints. In some embodiments, the extension arms or beams <NUM> and <NUM> may be coupled to each of the duct walls <NUM> and <NUM> via the joints <NUM> (e.g., welded and/or brazed joints), a clamp, a hinged joint, one or more removable fasteners (e.g., threaded fasteners or bolts), one or more fixed fasteners, or any combination thereof. Similarly, the mounting support or plate <NUM> may be coupled to each of the extension arms or beams <NUM> and <NUM> via one or more fasteners or joints <NUM>. In the illustrated embodiment, each of the fasteners or joints <NUM> includes a male threaded fastener <NUM> and a female threaded fastener <NUM>. The male threaded fastener <NUM> extends through the mounting support or plate <NUM> and the extension arm or beam <NUM> and <NUM> and connects with (is secured by) the female threaded fastener <NUM>. Additionally, or alternatively, the mounting support or plate <NUM> may be coupled to each of the extension arms or beams <NUM> and <NUM> by one or more other fasteners or joints, such as a welded joint, a brazed j oint, a hinge, a clamp, or one or more other fixed or removable fasteners.

<FIG> is a cross-sectional view of one of the bumpers <NUM> coupled to one of the sleeves <NUM> of the restraint system <NUM> of <FIG> and <FIG>. As illustrated, the bumper <NUM> is coupled to the sleeve <NUM> via an annular bracket <NUM> having opposite C-shaped portions <NUM> and <NUM> coupled together at lips <NUM> and <NUM>. In particular, the C-shaped portions <NUM> and <NUM> are contoured to fit about an annular exterior <NUM> of the sleeve <NUM>, while the lips <NUM> and <NUM> are coupled together by one or more fasteners <NUM> (e.g., a threaded male fastener <NUM> coupled to a threaded female fastener <NUM>). The threaded male fasteners <NUM> (e.g., bolt) extends through the lips <NUM> and <NUM> and threadedly couples with the female threaded fastener <NUM> (e.g., nut). The threaded fasteners <NUM> and <NUM> are configured to compress together the lips <NUM> and <NUM>, thereby compressing together the C-shaped portions <NUM> and <NUM> about the annular exterior <NUM> of the sleeve <NUM>. In some embodiments, the annular bracket <NUM> may be fixedly coupled to the annular exterior <NUM> of the sleeve <NUM> via a welded joint or a brazed joint. The bumper <NUM> also has the support bracket or arm <NUM> extending away from the annular bracket <NUM> and the sleeve <NUM> toward the bumper head <NUM>, which is configured to contact the heat exchanger <NUM> of the component <NUM>. In certain embodiments, the bumper head <NUM> may include one or more bumper layers or plates <NUM>, which may include a different material and/or a protective material configured to help protect the heat exchangers <NUM>.

As illustrated in <FIG>, the cable <NUM> in the illustrated sleeve <NUM> may include a plurality of individual cables or cable sections <NUM>. The individual cables <NUM> may be twisted together to define the cable <NUM>, the cables <NUM> may be completely independent from one another, or one or more materials may help bond the cables <NUM> together to define the cable <NUM>. As the cable <NUM>, including the cables or cable sections <NUM>, extends through the sleeve <NUM> within the flow path <NUM> of the duct <NUM>, the sleeve <NUM> is configured to protect the cable <NUM> from the exhaust gas flow <NUM> within the duct <NUM>. For example, the sleeve <NUM> may be configured to provide thermal protection, vibration protection, chemical protection, or any combination thereof. Accordingly, the sleeve <NUM> may include a material resistant to heat, corrosion, erosion, or any combination thereof. In certain embodiments, the sleeve <NUM> may be constructed of a stainless steel material.

As discussed above, the tensioners <NUM> of the tension assembly <NUM> may include one or more types of tensioners being used alone or in combination with one another to adjust a tension of each cable <NUM> in the cable and sleeve assembly <NUM>. Examples of these tensioners <NUM> are discussed below with reference to <FIG>. The representation of the tensioners <NUM> in <FIG> and <FIG> is intended to include any one or more of the tensioners <NUM> of <FIG> in combination with one another, wherein the tensioners <NUM> may be used in series arrangements, parallel arrangements, or a combination thereof.

<FIG> is a schematic of an embodiment of the tensioner <NUM>, illustrating a spring tensioner <NUM> having a helical spring section <NUM> extending between opposite connectors <NUM> and <NUM>. In the illustrated embodiment, each of the connectors <NUM> and <NUM> includes a ring or loop at opposite terminal ends of the spring tensioner <NUM>. For example, the connector <NUM> may be configured to couple to the cable <NUM> or another tensioner <NUM>, the connector <NUM> may be configured to couple to the mount <NUM> or another tensioner <NUM>, or any combination thereof. In certain embodiments, the tensioner <NUM> of <FIG> may include a plurality of the spring tensioners <NUM> disposed in parallel, in series, or a combination thereof. Additionally, one or more of the spring tensioners <NUM> may be used in combination with one or more of the tensioners <NUM> of <FIG>.

<FIG> is a schematic of an embodiment of the tensioner <NUM> including a turnbuckle <NUM>. The illustrated turnbuckle <NUM> includes a body <NUM> having threaded bores <NUM> and <NUM>, an eye bolt <NUM> having a connector <NUM> coupled to a threaded shaft <NUM>, and an eye bolt <NUM> having a connector <NUM> coupled to a threaded shaft <NUM>. Each of the eye bolts <NUM> and <NUM> is configured to thread into the body <NUM> at the threaded bores <NUM> and <NUM>, respectively. In particular, the threaded shaft <NUM> threadedly engages with the threaded bore <NUM>, while the threaded shaft <NUM> threadedly engages with the threaded bore <NUM>. The threads of the threaded shaft <NUM> of the eye bolt <NUM> are opposite from the threads of the threaded shaft <NUM> of the eye bolt <NUM>. For example, the eye bolts <NUM> and <NUM> may have opposite handedness in the threads, such as a right-hand thread and a left-hand thread. The connector <NUM> may be configured to couple with the cable <NUM>, another one of the tensioners <NUM> such as the spring tensioner <NUM>, or any combination thereof. Similarly, the connector <NUM> may be configured to couple to the mount <NUM>, another one of the tensioners <NUM>, or any combination thereof. Additionally, one or more of the turnbuckles <NUM> may be used in combination with one or more of the tensioners <NUM> of <FIG> and <FIG>.

<FIG> is a schematic of an embodiment of the tensioner <NUM> including a fluid driven tensioner <NUM> configured to be used alone or in combination with one or more of the other tensioners described in <FIG>, and <FIG>. In the illustrated embodiment, the fluid driven tensioner <NUM> includes a piston <NUM> disposed within a cylinder <NUM> of a body <NUM>. The body <NUM> may include a generally annular body having an annular side wall <NUM> and opposite end walls <NUM> and <NUM>. The end wall <NUM> may be coupled to the mount <NUM>, which may be fastened to the mounting support or plate <NUM> of <FIG> via one or more threaded fasteners <NUM>, such as threaded bolts. The piston <NUM> is coupled to a shaft <NUM> having a connector <NUM> disposed outside of the body <NUM>. The shaft <NUM> is generally sealed in the end wall <NUM> of the body <NUM>, such as with one or more annular bushings or seals. The connector <NUM> may include a connector ring or loop, which may be connected to the cable <NUM>, one or more of the other tensioners <NUM> described herein with reference to <FIG>, and <FIG>, or any combination thereof.

The piston <NUM> is disposed in the cylinder <NUM> between opposite chambers <NUM> and <NUM>. The chamber <NUM> is coupled to a supply conduit <NUM>, while the chamber <NUM> is coupled to a discharge conduit <NUM>. The supply conduit <NUM> is coupled to a valve <NUM>, a pump <NUM>, and a fluid supply <NUM>. The fluid supply <NUM> is configured to supply a fluid, such as a liquid or gas, to the pump <NUM>. The pump <NUM> is configured to pump the fluid through the supply conduit <NUM> into the chamber <NUM> to bias movement of the piston <NUM>. The valve <NUM> is configured to open when supplying the fluid to the chamber <NUM>, and the valve <NUM> is configured to close to hold fluid pressure in the chamber <NUM> and hold a position of the piston <NUM>. As the fluid supply <NUM> supplies the fluid to move the piston <NUM>, the shaft <NUM> adjusts tension in the cable <NUM> of the cable and sleeve assembly <NUM>. The discharge conduit <NUM> includes a valve <NUM> configured to open and close to release or hold pressure within the chamber <NUM>. For example, when the piston <NUM> is driven by fluid pressure in the chamber <NUM>, the discharge conduit <NUM> may release pressure from the chamber <NUM> by opening the valve <NUM>. In the illustrated embodiment, the controller <NUM> may be communicatively coupled to the pump <NUM> and the valves <NUM> and <NUM> to control operation of the piston <NUM>, thereby adjusting the tension applied by the shaft <NUM> to the cable <NUM>. Again, the fluid driven tensioner <NUM> may be used alone or in combination with the other tensioners <NUM> of <FIG>, and <FIG>.

<FIG> is a schematic embodiment of the tensioner <NUM> including an electric driven tensioner <NUM>. In the illustrated embodiment, the electric driven tensioner <NUM> incudes one or more electric motors <NUM> (e.g., AC motors and/or DC motors), one or more gear assemblies <NUM>, and a shaft <NUM> having a connector <NUM>. The electric motor <NUM> may be communicatively coupled to the controller <NUM>, which may be configured to control at least one or more of the rotational direction, speed, or torque of the electric motor <NUM>. The electric motor <NUM> may be configured to rotate a shaft <NUM> coupled to the gear assembly <NUM>, and the gear assembly <NUM> may be configured to convert the rotational motion of the shaft <NUM> into a linear motion of the shaft <NUM>. The shaft <NUM> moves the connector <NUM>, which may be coupled to the cable <NUM>, one or more of the tensioners <NUM>, or any combination thereof. Additionally, the electric motor <NUM> may be coupled to the mounting support or plate <NUM> of <FIG> via the mount <NUM> and fasteners <NUM> as discussed above with reference to <FIG>. In certain embodiments, the electric driven tensioner <NUM> may be used with one or more of the tensioners <NUM> of <FIG>, <FIG>.

<FIG> is a schematic embodiment of the tensioner <NUM> including a manual tensioner <NUM>. In the illustrated embodiment, the manual tensioner <NUM> includes a rotatable hand wheel <NUM> coupled to a shaft <NUM> having a threaded shaft portion <NUM>, which engages with a threaded nut <NUM>. The threaded shaft portion <NUM> and the threaded nut <NUM> are disposed within a body <NUM>, such as an annular body extending along the threaded shaft portion <NUM>. The threaded nut <NUM> may be inhibited from rotation via an axial slot <NUM> that engages an axial anti-rotation protrusion <NUM> disposed along an interior of the body <NUM>. Accordingly, as the wheel <NUM> is rotated to cause rotation of the threaded shaft portion <NUM>, the threaded nut <NUM> moves axially along the anti-rotation protrusion <NUM>, thereby causing linear movement of a linking arm <NUM> coupled to the threaded nut <NUM>. The linking arm <NUM> further includes a connector <NUM>, such as a loop or ring, which may be coupled to the cable <NUM>, one or more additional tensioners <NUM>, or any combination thereof. In certain embodiments, the manual tensioner <NUM> may be used with one or more of the tensioners <NUM> of <FIG> and <FIG>.

<FIG> is a schematic embodiment of the tensioner <NUM> including a counter-weight tensioner <NUM>. As illustrated, the counter-weight tensioner <NUM> includes a counter-weight <NUM> coupled to a cable <NUM>, which moves along a pulley <NUM>. The pulley <NUM> may be mounted to the mounting support or plate <NUM>, one of the duct walls <NUM> or <NUM>, or another structure via a mounting arm <NUM>. The cable <NUM> may include opposite connectors <NUM> and <NUM>. The connector <NUM> may include a loop or ring, which is coupled to a corresponding fastener or hook <NUM> of the counter-weight <NUM>. The connector <NUM> may include a loop or ring, which is configured to couple to the cable <NUM>, one or more additional tensioners <NUM>, or any combination thereof. Accordingly, the counter-weight <NUM> may be sized to provide a sufficient amount of tension in the cable <NUM> and the cable <NUM> of the restraint system <NUM> with or without additional tensioners <NUM>. In certain embodiments, the counter-weight tensioner <NUM> may be used with one or more of the tensioners <NUM> of <FIG>.

The tensioners <NUM> illustrated in <FIG> are intended to be used alone or in any combination with one another as the one or more tensioners <NUM> of <FIG> and <FIG>. For example, in certain embodiments, one or more of the spring tensioners <NUM> of <FIG> may be used in combination with one or more of the turnbuckles <NUM> of <FIG>. Additionally, the spring tensioner <NUM> may be used in combination with one or more of the fluid tensioners <NUM> of <FIG>, the electric-driven tensioners <NUM> of <FIG>, the manual tensioners <NUM> of <FIG>, the counter-weight tensioners <NUM> of <FIG>, or any combination thereof. The illustrated tensioners <NUM> of <FIG> may be used in various series arrangements, parallel arrangements, or any combination thereof. Accordingly, for each of the tensioners <NUM> on each side of the duct <NUM> at both of the upstream and downstream cable and sleeve assemblies <NUM> and <NUM> as illustrated in <FIG> and <FIG>, the tensioners <NUM> of <FIG> may be used alone or in combination with one another to adjust the tension in each of the cables <NUM>.

Technical effects of the disclosed embodiments include a restraint system <NUM> having a vibration damping system <NUM> with a tension assembly <NUM> and a cable and sleeve assembly <NUM> configured to provide stiffness when holding components <NUM> (e.g., heat exchangers <NUM>) in place along a flow path <NUM>. The cable and sleeve assembly <NUM> includes sleeves <NUM> that protect cables <NUM> from the exhaust gas flow <NUM> along the flow path <NUM>, while a tension in the cables <NUM> is adjustable via tensioners <NUM> of the tension assembly <NUM> to change the stiffness in the cable and sleeves assembly <NUM>. The vibration damping system <NUM> also includes a bumper assembly <NUM> having a plurality of bumpers <NUM> coupled to the sleeves <NUM> and making contact with upstream and downstream sides of the components <NUM>. In operation, the tensioners <NUM> are configured to adjust the tension in the cables <NUM> to change the stiffness and detune the natural frequencies of the components <NUM> away from the excitation load frequencies in the HRSG <NUM>. The cable and sleeve assemblies <NUM> are substantially lighter than rigid restraints and provide flexibility to help reduce the possibility of resonance in the components <NUM>.

Claim 1:
A system (<NUM>), comprising:
a restraint system (<NUM>) configured to support a heat exchanger (<NUM>) along a flow path within a duct (<NUM>), wherein the restraint system (<NUM>, <NUM>) comprises:
a first sleeve (<NUM>) configured to extend between opposite first and second walls (<NUM>, <NUM>) of the duct (<NUM>);
a first cable (<NUM>) extending through the first sleeve (<NUM>); and
a first bumper (<NUM>) coupled to the first sleeve (<NUM>), wherein the first bumper (<NUM>) is configured to contact the heat exchanger (<NUM>); and
a first tensioner (<NUM>, <NUM>) coupled to the first cable (<NUM>), wherein the first tensioner (<NUM>, <NUM>) is configured to provide a first tension in the first cable (<NUM>) to adjust a stiffness of the restraint system (<NUM>) and to adjust a natural frequency of the heat exchanger (<NUM>) away from an excitation load frequency.