In this paragraph, I am going to explain about alignment guides. Firstly they are designed to be installed next to expansion joints. Secondly they are made of steel pipe and copper tube that runs to maintain the center-line of the pipe/tube. Next expansion joints are large-structure. Furthermore low-mass technology resulting in minimum weight while providing 3-Dimensional alignment using the conservative Spider & Cylinder arrangement.
Moreover, pipe or copper tube systems that incorporate expansion joints, ball joints, or loops to absorb expansion must include three additional major elements. Main and/or intermediate anchors, supports, and alignment guides.
Requirements follow the Standards of the EJMA, Inc. Do not include internal guides require an alignment guide to be located 4 diameters from the face of the expansion joint. Expansion joints additional guide 14 diameters from the first guide. Expansion joints with internal guides require only one alignment guide to be located 10-14 diameters from the expansion joint.
The maximum alignment guide spacing in the intermediate portion of the run is a function of the pipe/tube properties (modulus of elasticity and moment of inertia) the design pressure, and the expansion joint effective area and spring force.
Steel Pipe Guides
Alignment Guides manufactures and inventories standard for nominal pipe size (NPS) steel pipe from 3/4” through 14” with varying insulation thickness. Hot dipped galvanizing or all stainless steel construction are also available. In tight spaces, rotated housings are available. The maximum operating temperature is 500°F. All stainless steel construction is also available to provide greater corrosion resistance, higher temperatures, or cryogenic systems.
Copper Tube Guides
Alignment Guides manufactures and inventories standard for standard size copper tube from 3/4” through 4” with varying insulation thickness. Hot dipped galvanizing is available as an option. In tight spaces, rotated housings are available. The maximum operating temperature is 400°F. All stainless steel construction is also available to provide greater corrosion resistance.
Choose Steel Pipe or Copper Tube, then locate correct Table.
Select the size.
Select insulation clearance: a maximum value equal to or greater than the insulation thickness to be installed.
Verify the Alignment Guide Expansion/Travel stated is equal or greater than the motion occurring at the guide location. For additional expansion increase the last part number indicator as needed.
For Hot dipped galvanized steel or stainless steel materials, select one of these options below in the example.
Confirm the guide housing “A” spacing will fit into the system. If it does not, select the “-45” degree housing and spider option and re-verify the spacing.
Pipe Alignment Guides
A pipe alignment guide is also known as a spider alignment guide. Pipe alignment guides are designed to take care of the axial alignment of piping because it expands and contracts during operation. it’s most typically installed adjacent to expansion joints and at reasonable distances between the expansion joint and therefore the anchor point. we’ve a variety of sizes 1″ through 24″ pipe and insulation thickness of 1″ through 4.” Also available in copper tube sizes. Spider alignment guides are usually steel or any material you would like are often plain or Hot-Dip Galvanized with Zinc Plated Bolts & Nuts For maintaining alignment of piping through its axial expansion and contraction cycles.
Normally, two or more pipe alignment guides are used on one piping run to avoid a pivoting effect within the piping system. it’s recommended that the primary guide be located a maximum of 4 pipe diameters from an expansion joint. The second guide should be placed a maximum of 18 pipe diameters from an expansion joint. Additional guides should be used in accordance Supports are usually required between the intermediate guides to suits standard support practice. Maximum temperature 650° F
1. Attach outer housing to structure by bolting or welding. 2. Remove upper section of housing to open position. 3. Attach spider clamp to pipe and completely insulate. 4. Set pipe and spider clamp into outer housing. 5. Replace upper section of housing to closed position and secure.
Ordering: Specify size number, pipe size, insulation, thickness, figure number, name and finish.
Spider Alignment Guides
Proper pipe alignment is significant to maximize service from expansion joints. These spider alignment guides permit free axial movement of the pipe. Therefore, restricting lateral and angular movement. Location of pipe alignment guides Whenever possible, install the expansion joint on the brink of an anchor. Firstly, locate the anchor or first spider alignment guide. It should be no quite 4 pipe diameters from the expansion joint. Then the second guide should be located no quite 14 pipe diameters from the primary guide.
Guides for Piping
Pipe Alignment Guides should be utilized in conjunction with expansion joints. Spider alignment guides help to regulate the motion of pipe and expansion joints, insuring that the joint is subject only to the deflection that it had been designed. Unguided piping, struggling will tend to buckle, sometimes severely. This buckling would deter the expansion joints from working properly. They permit unobstructed axial movement of the pipe while restricting lateral, angular, or buckling movements. Standard spider guides are manufactured to accommodate specific amounts of movement and insulation. A pipe guide assembly consists of an anchored housing and a sliding spider that’s attached to the pipe. T
In this paragraph, I am going to explain about expansion compensators. Firstly they are designed for installations where the principal movement is axial. Secondly standard designs are 3/4” through 4” for steel pipe and copper tube with 2” or 3”axial compression. Next copper tube ends are male or female sweat connections. The pipe or tube, telescopes into the compensator providing a smooth full bore. Therefore, it isolates the bellows from the flow.
Sizes 3/4” through 4.”
Threaded, welded, flanged, and grooved steel pipe joints.
Male and female copper sweat ends.
Design pressure: 200 psig—see Copper Tube.
Axial travel: 2” and 3.”
Fully enclosed and externally pressurized, multiply stainless steel bellows.
Internal guides maintain alignment.
Expansion compensators provide a maintenance-free, compact, economical, and reliable method of eliminating this problem. Moreover the compact design of Expansion Compensators permits installation within tight spaces. And the inline construction minimizes pressure drop and heat loss. And the metal bellows is fully enclosed, and internal and external guides maintain alignment. Moreover, all welded or high-temperature brazed construction eliminates the need for maintenance.
Expansion Compensators are designed for installations where the principal movement is axial. Also standard joints are designed for 2” or 3” axial compression (pipe expansion) and 0.5” extension. If the primary movement is extension (pipe contraction), the expansion compensator can be preset at the factory. The piping system must include anchors to react the force produced by pressure thrust and the bellows.
In this paragraph, I am going to tell you about installation. Firstly, Expansion Compensators are available for 2″ and 3″ axial travel. Secondly check the specification for the allowable travel of the product. But be certain that the system conditions and test conditions do not exceed these values. Guides, supports, anchors: Expansion Compensators are designed for applications where the principal movement is axial to the centerline of the compensator, and the system includes guides, supports, and anchors. Finally the flow can be in either direction. But not exceed 1000°F during installation.
In this paragraph, I’m going to tell you about Formed Metal Bellows. They are reliable, and has a long life. In addition to Formed Metal Bellows come in standard sizes ranging from 1-inch to 40-feet inside diameter. Thus gives formed metal bellows a broad spectrum of pressure, temperature, flexibility, and movement requirements while conveying both corrosive and non-corrosive fluids. Next these bellows absorb axial extension and compression, parallel offset, angulation, or combinations of motions. However, our engineering assistance is available to you for your special applications or non-standard sizes.
Formed Metal Bellows, are used for high-vacuum applications. Therefor, requiring leakage rates less than 1 x 10-10 STD ATM CC/SEC at base pressure of 1 x 10-6 TORR. Since most of these applications require extremely flexible bellows, Dannenbaum LLC recommends materials thickness of 0.006” for inside diameters (I.D.) up to 4.5”, 0.008”for I.D. up to 8.0”, and 0.010” for I.D. up to 14.” Material Thickness can be used which has a maximum pressure (Column 7 on pages 6-17) exceeding 15 PSIG.
The beryllium copper alloys have high thermal and electrical conductivity similar to pure copper, and can be readily joined by resistance and fusion welding, brazing and soldering. The material is nonsparking, nonmagnetic; it has high galling resistance, and maintains its strength and ductility at cryogenic temperatures. A formed metal bellow is a metal expansion joint. And a metal expansion joint is a pipe expansion joint.
Bellows fabricated in any standard-size with multiply construction up to four plies of equal thickness. Furthermore, the maximum pressure, spring rate, and stability pressure are increased in direct proportion to the number of plies. But with the same axial deflection as a single ply. Multiply design permits a lower spring rate and a greater cycle life than a single ply configuration for an equivalent pressure.
In this paragraph, I am going to tell you about Perma-Pax Packed Expansion Joints. First thing they are designed for installations where the principal movement is axial. Next standard single and dual designs are available 2″ through 24″ diameter with travels of 4″, 8″ and 12″ compression for single designs, and 8″, 16″ and 24″ compression for dual designs. Furthermore, service conditions are 150 and 300 psig to 500°F. Moreover, welded and flanged end connections are standard, with grooved ends optional.
Perma-Pax Packed Expansion Joints incorporate design features that are not available from other companies. Additionally they include a one piece body which eliminates a circumferential weld. And line bored aluminum bronze metal inner and outer guides. And an optimized sealing system consisting of carbon fiber graphite impregnated braided packing combined with Grafoil® Flexible Graphite injected packing. These features combine to provide a standard product with the lowest seal resistance force available, self lubrication, and precision internal metallic guides.
Standard designs sizes 2″ through 24″, 150 & 300 PSIG at 500°F.
Axial travel of 4″, 8″ & 12″ for single configurations, 8″, 16″ & 24″ for dual anchor base configurations.
Line bored abrasion free aluminum bronze internal & external guides.
Self lubricating maintenance free.
They can be repacked under full system pressure.
In this paragraph, I am going to tell you about quality. Firstly Perma-Pax Packed Expansion Joints are a premium quality product with standard features. And the sealing system consists of carbon fiber yarn impregnated with graphite. Particularly these sealing materials remain flexible throughout the service life of the expansion joint. Therefore, have the added benefit of providing lubrication to the traveling pipe.
In addition to, these design features combined with the quality system that includes welding to ASME Code Section IX, and hydrostatic testing and cycling of all Perma-Pax expansion joints, assure the user of a quality extended life product. Design conforms to ASTM F 1007 and Mil-E-17814. We can help design and manufacture expansion joints for custom applications. Which include elevated pressure, and temperature service, special materials, and diameters greater than 24″. A perma-pax expansion joint is a type of metal expansion joint. Click here to read the blog post about pipe expansion joints.
Particularly expansion joints are designed for installations where the principal movement is axial. Furthermore single configurations are 4″, 8″ and 12″ of axial compression (pipe expansion) and 1″, 1.5″ and 2″ extension respectively. Then, if the primary movement is extension (pipe contraction), the expansion joint can be preset at the factory. Finally the piping system must include anchors to react the force produced by pressure thrust and the friction force, supports to react the weight of the pipe and media, and guides to ensure that the pipe alignment is maintained.
In this article, I am going to tell you about bellow pump connectors and flow liners. Mechanical equipment usually needs a pump connector. Futhermore, this helps with vibration, absorb small pipe movements. And to provide flexibility during installation. In addition to, for help with flexibility, and fatigue resistance use bellows. Additionally standard configurations include limit rods to react to the pressure thrust or compression for vacuum conditions. Finally bellows pump connectors installed on the pump to absorb motion.
Sizes 1-1/2” through 24”
Design Conditions: full vacuum to 150 and 300 psig at 500°F
Compact design with maximum flexibility and extended life
Standard configurations include limit rods to react the pressure thrust or compression for vacuum conditions. Limit rods with flow liners help with the most difficult applications. Standard configurations are available from inventory. Consult the factory for non-standard designs involving special materials or design conditions.
Bellows pump connectors are designed to connect piping to mechanical equipment that has thermal growth or mechanical movement. Limit rods are an necessary part of the design to prevent over extension or compression. Therefore, install the rods lose for full benefit. The rigid anchor must be capable of reacting the pressure thrust and the spring force of the bellows. Bellow pump connectors are a type of metal expansion joints.
Flow liners or internal sleeves are optional features on standard Bellows Pump Connectors. Internal sleeves have several purposes. Firstly is to minimize pressure loss. Next is to prevent bellows resonance in turbulent flow. Also prevent erosion of the bellows. Furthermore to prevent direct impingement of high temperature flow on the bellows.
In this paragraph, I am going to talk about some of the EJMA has guidelines for bellows pump connectors and flow liners. Firstly flow liners are recommended for gas flow. Secondly liners are recommended for liquid flow. Next liners are designed for unidirectional flow, and flow conditions normally experienced in industrial and HVAC applications. Finally, for conditions involving bi-directional flow, high velocities, abrasive materials or extreme turbulence, consult the factory.
Flexible pump connectors also know as metal hose pump connectors. help protect your equipment by absorbing vibrations and noise, connects misaligned rigid piping, connects moving parts of machinery or equipment. Therefore, is practical for hooking up frequently moved or dismantled equipment. Also the metal hose and braid are very heavy duty industrial products.
Depending on the application will decide if a metal product is needed in the first place. Next is to decide if the application better for a hose or metal expansion joint. Expansion joints are better used to handle axial movements. Metal bellows also know as metal expansion joint is better to handle vibration.
Stainless Steel Braided Flexible Pump Connectors
Stainless Steel Braided Flexible Pump Connectors are made from a standard flexible corrugated 321 stainless steel core hose covered by a 304 SS wire braid, other materials are available. The standard is Flat face flange end connections. but are also available with: (Male nipples, 150# R.F., 300#, Grooved, Unions, Weld ends, JIC, other specially designed connectors in Carbon Steel, Stainless). Furthermore, The wire-braided cover is used over the flexible core hose to provide additional strength for the rated operating pressure. Assemblies available unbraided, single, or double braided.
Flexible Pump Connectors help protect your equipment by absorbing vibrations and noise. As well as connects misaligned rigid piping. Also connects moving parts of machinery or equipment. And is practical for hooking up frequently moved or dismantled equipment.
Braid & Braided Product
We supply a wide variety of braid and braided products. Braid is a flexible wire sheath surrounding a metal hose that prevents the hose from elongation created by internal pressure. Braid is composed of a number of wires wrapped helically around the hose while at the same time going under and over each other in a basket weave fashion.
Our braid is produced and stocked in various alloys including:
304L, 316L and 321 Stainless Steel
Inconel alloy 625
Other alloys and material of construction are available upon request.
PFPC – Flanged Pump Connectors
In this paragraph, I’m going to tell you about key features of flanged pump connectors. Firstly they are designed to absorb vibration in a piping system. Secondly flanged pump connectors are 321 or 316L stainless steel corrugated hose and braid. Next they are ASTM A36L stainless steel class 150 slip-on plate flanges.
TC – Threaded Pump Connectors
In this paragraph, I’m going to tell you about threaded pump connectors. Firstly threaded pump connectors are designed to absorb vibration in piping system. Secondly they are 321 or 316L stainless steel corrugated house or steel braid. Lastly they are schedule 40 carbon steel, 304 or 316 male nipple ends.
In this Paragraph, I am going to talk about V-Flex Connectors. Firstly they are designed to absorb thermal expansion or contraction, or for seismic isolation of steel pipe or copper tube installations. Next the braided metal hose elements that are incorporated into the design offer benefits that are not available in other products that are used for these applications, and the unique “V” configuration provides advantages over other metal hose connectors.
Thermal Expansion Applications
V-Flex Connectors are available as standard products for 1/2″ through 4″ nominal pipe size. They also have stainless steel braided hose and steel fittings – flanged, weld end or grooved. Design conditions are 150 psig and 500ºF with a choice of 2″, 3″ or 4″ of travel.
V-Flex Connectors installed for seismic separation require an intermediate anchor on each side, if the separation that is no greater than the overall length of the V-Flex Connector plus four pipe diameters on each side. Furthermore, if the separation is greater, an alignment guide must be installed within four pipe diameters from the V-Flex.
Moreover, alignment guides do not provide support for the weight of the system. Therefore, it may be necessary to install additional guides for long flexible runs to ensure alignment.
Guides, Supports, Anchors
V-Flex Connectors require anchors, guides and supports. Refer to us for for the guide and anchor requirements. It may be necessary to support the center elbow of the connector- refer to the illustrations of horizontal and vertical installations.
The flow can be in either direction.
POST INSTALLATION INSPECTION
Inspect the connector for damage with special attention to the wire braid.
Is the connector at the correct location as specified?
Are the anchors and guides correctly installed? Are the guides free to move?
In this paragraph, I am going to talk about externally pressurized expansion joints. Firstly they are designed for installations where the principal movement is axial. Secondly standard single and dual designs are available 2” through 24” NPS with 4” through 16” axial compression. Next service conditions are 150 and 300 psig to 500°F. Then welded and flanged end connections are standard, with grooved ends optional. Moreover, Standard in-line pressure balanced configurations are available 2” through 24” NPS with 4”, 6” & 8” axial travel rated for 150 & 300 psig to 500°F. Finally pipe telescopes into the expansion joint protecting the bellows and providing a smooth full bore interior. Additionally contact us for a quote or more information.
• Standard Designs Sizes 2″ through 24″, 150 & 300 PSIG at 500°F • Axial Travel of 4″, 6″ & 8″ for Single Configurations 8″, 12″ & 16″ for Dual Anchor Base Configurations.
Maximum Flexibility and Extended Life
Low Spring Forces and Pressure Thrust
Standard In-Line Pressure Balanced Configurations
Since the media is on the exterior of the bellows it is self draining, and bellows instability or squirm is not a consideration. Rigid guides on the interior and exterior ensure alignment of the bellows. The proven design of externally pressurized expansion joints excels because of close attention to detail design and high quality workmanship. These designs offer an affordable product with a proven service record without the use of expensive high nickel alloys.
Externally Pressurized Expansion Joints
Externally pressurized expansion joints are designed for installations where the principal movement is axial. Standard single configurations are designed for 4″, 6″ and 8″ of axial compression (pipe expansion) and 1″, 2″ and 2″ extension respectively. Dual configurations are designed for 8″, 12″ and 16″ of axial compression and 2″, 4″ and 4″ extension respectively. If the primary movement is extension (pipe contraction) the expansion joint can be preset at the factory. The piping system must include anchors to react the force produced by pressure thrust and the bellows spring constant, supports to react the weight of the pipe and media, and guides to ensure that the pipe alignment is maintained.
Low Pressure Round and Rectangular Expansion Joints have been specifically designed for round and rectangular low pressure duct and piping applications. Applications such as diesel engine exhaust, gas turbine exhaust, ventilation ducting, and boiler exhaust ducting. The designs are highly flexible, and a variety of materials are available for high temperatures or corrosive applications. Specifications vary for each product group but in general round expansion joints are designed for pressures ranging from full vacuum to 15 psig.
Laminated Bellows Connectors are expansion joints designed to be highly flexible with internal vibration damping for direct installation on vibrating equipment such as engine exhausts, turbochargers and fan connections. Sizes range from 3″ through 18″ nominal pipe size with fixed, floating and weld end connections.
Laminated Bellows Expansion Joints are designed specifically for low pressure applications such as engine exhaust systems, fan connectors, ventilation ducting and air handling systems. The laminated bellows construction permits axial, lateral and angular movements without exerting high spring forces on the system, and the internal damping provided by the laminations limits resonate vibration. Laminated Bellows Expansion Joints are ideal for direct installation on engine exhaust manifolds, turbochargers and fan inlet and exhaust connections. Round Expansion Joints are similar designs with single ply bellows that less suitable for vibration applications but ideal for use throughout the ducting and piping. Sizes range from 6″ through 48″ diameter.
All Laminated Bellows Expansion Joints are designed for a maximum pressure (including test pressure) of 15 psig and a full vacuum. They are intended for applications such as engine exhaust, fan connections, vents and other very low pressure applications. The design temperature varies with the construction. The materials of construction for standard assemblies are: type 304 stainless steel bellows, van stone ends and flow liners; ASTM A-36 carbon steel plate flanges and angle flanges, and ASTM A-53 standard weight carbon steel pipe weld ends. Optional materials are available including the substitution of stainless steel for flanges and pipe.
The lateral offset installation illustrated is a typical application of a Laminated Bellows Expansion Joint installed on an engine exhaust, fan intake or discharge. The high flexibility and internal damping provided by the laminated construction permits absorption of lateral movement from thermal expansion or mechanical motion. Refer to Column 5 of the Design Data for the maximum lateral off-set of each configuration. For applications of this type it is good practice to add Tie Rods to the expansion joint – see Tie Rods below.
Tie rods are available as an option on Laminated Bellows Expansion Joints. They react the pressure thrust in piping and ducting that is not anchored such as the lateral offset application illustrated above. They may also function as Limit Rods. Limit rods do not react the pressure thrust in service but they are designed to react the pressure thrust in the event of an anchor failure. Their main function is to limit the axial extension and compression of the bellows to the rated values. This normally refers to both tie rods and limit rods as Tie Rods but the factory settings are important - factory settings as Tie Rods do not permit axial extension but limits compression to the rated value of the bellows. Factory settings as Limit Rods will permit axial extension and compression in accordance with the rated travel specified in the Design Data.
Flow liners or internal sleeves are optional features that are available for all configurations. Liners provide a means of isolating the bellows element from direct contact with the flow and as a result eliminating flow induced vibration, minimizing pressure loss and creating dead air space between the bellows that insulates the bellows. We installed flow liners follow the recommendations outlined in the Standards of the Expansion Joint Manufacturers Association (EJMA) summarized as follows.
Example: 12″ nominal diameter Single fixed flange, Standard bellows material, 304 stainless steel Standard Flange Material, A-36 carbon steel 3.0″ axial compression, 1.5″ extensiona
Operating Conditions: Laminated Bellows Expansion Joints are designed for applications where the pressure including tests does not exceed 15 psig. The design temperature varies with the configuration and materials of construction. Consult the purchase specification for the design temperature and the rated travel of the product purchased. Be certain that the system operating conditions and test conditions do not exceed the rated values.
Guides, Supports, Anchors: Laminated Bellows Expansion Joints are light weight construction. Guides, supports and anchors are important to prevent damage. Refer to the installation drawings for the correct location.
Flow Direction: The flow direction can be from either direction for expansion joints that do not include a flow liner. The flow direction for expansion joints with flow liners is from the fixed (welded) end to the free end and indicated on the exterior. Confirm that the joint is oriented correctly.
Shipping Restraints: External restraints are installed at the factory to ensure installation at the correct length and alignment. They are painted yellow and labeled – Shipping bars, remove after installation. Leave these restraints installed until after the installation of the expansion joint is complete – but they must be removed prior to pressure testing and operating the system. CAUTION: Shipping restraints may be installed by welding. Provide protection for the bellows element from cutting or grinding during removal.
Tie Rods: Tie rods, limit rods and control rods are devices that limit the travel of the expansion joint. They are available as an option on Laminated Bellows Expansion Joints. If they are included, be certain that the installation allows the design movement of the expansion joint.
Post Installation Inspection
Round Expansion joints are available in standard designs from 6″ through 48.” Has the capability to manufacture expansion joints with diameters up to 34 feet. Standard end connections are fixed flange, floating flange, angle flange and weld end. They are available as single joints or universal configurations. Round Expansion Joints
Round Expansion Joints
Sizes 6" through 48" diameter
Austenitic stainless steel and high nickel alloy bellows
Wide selection of end fittings
Designed for maximum flexibility and fatigue life
Light weight construction
Round Expansion Joints are specifically designed for light weight circular ducting used for engine exhaust systems, flue stacks, fan connectors, ventilation ducting and air handling systems. The bellows are designed to absorb axial, lateral and angular movements without exerting high spring forces on the system. Standard designs are ideally suited for engine exhaust manifolds, turbocharger exhaust connectors, and fan inlet and exhaust connectors. The standard designs can also be adapted to special configurations with special flanges, transitions and elbows. Refer to Laminated Bellows Expansion Joints for sizes 3″ – 18″ for similar expansion joints with high internal damping for applications with vibration or oscillation. Design Conditions
All Round Expansion Joints are designed for a maximum pressure (including test pressure) of 15 psig and a full vacuum. The design temperature varies with the material used for construction.
The materials of construction for standard assemblies are Type 304 stainless steel for the bellows, van stone ends and flow liners, and A-36 carbon steel plate flanges and angle flanges, A-53 standard weight carbon steel pipe or A36 fabricated ducting. Optional materials are available including the substitution of stainless steel for flanges and pipe.
The lower expansion joint in the illustration is a typical application of a expansion joint installed at an engine or fan discharge. The motion for this joint is primarily lateral. Column 4 of the Design Data indicates the rated values for each configuration. If the required motion exceeds the rated value, a Universal Expansion Joint should be considered as described below. For applications of this type it is good practice to add Tie Rods to the expansion joint – refer to the Tie Rod section below. The rated motions are for conditions resulting from thermal expansion. High frequency motions such as those caused by excessive engine roll or vibration may cause fatigue of the expansion joint. Consultant the factory for these applications.
Two or more joints are required if the motion exceeds the rated value of a single joint. The Intermediate Anchor is necessary to ensure that each joint absorbs the required motion. It is good practice to design the Intermediate Anchor for loads equal to the spring force at full travel.
Universal Expansion Joints
Universal Expansion Joints are two bellow elements separated by a pipe spool. They are designed primarily for lateral movement. Unlike a single expansion joint that absorbs lateral motion by reshaping the bellows centerline, universal joints absorb lateral motion by angular displacement of the bellows elements. As a result, as the joint length increases, the lateral motion capability increases and the forces and moments acting on the adjacent equipment decrease. The application of a universal expansion joint is a very effective method of absorbing lateral motions with minimum loading on equipment.
Since most low pressure piping and ducting is not as rigidly anchored and guided as high pressure systems, tie rods are recommended for universal expansion joints. Tie Rods react the pressure thrust, protect the bellows elements from over extension or compression, and control and react the weight of the center spool. The illustration shows the stops that limit the travel and the center spool support. Longer tied universal expansion joints typically have to supports on each rod to guide the center spool. In addition the expansion joint can be incorporated into pipe runs where the expansion joint extends the length of the run, and the expansion of the run is absorbed within the tie rods as well as absorbing the expansion of the adjacent run by lateral offset.
Tie rods are available as an option on single and universal expansion joints. They react the pressure thrust in piping and ducting that is not anchored such as the lateral application for single expansion joints and the universal expansion joint. They may also function as limit rods. Limit rods do not react the pressure thrust in service but they are designed to react pressure thrust in the event of an anchor failure. Their main function is to limit the axial extension and compression of the bellows to the rated values. Normally refers to both tie rods and limit rods as Tie Rods but the factory settings are important – factory settings as Tie Rods do not permit extension but limits compression to the rated value of the bellows. Factory settings as Limit Rods will permit axial extension and compression in accordance with the rated travel specified in the Design Data.
or internal sleeves are optional features that are available for all configurations. Liners provide a means of isolating the bellows element from direct contact with the flow; therefore eliminating flow induced vibration, minimizing pressure loss and creating dead air space that provides insulation. Installed flow liners follow the recommendations outlined in the Standards of the Expansion Joint Manufacturers Association, Inc. (EJMA) summarized as follows.
Flow liners are recommended for:
Gas applications exceeding 4 ft./sec./inch of diameter up to 6" NPS
Gas applications exceeding 25 ft./sec. over 6" NPS.
Liquid applications exceeding 2 ft./sec./inch of diameter up to 6" NPS.
Liquid applications exceeding 10 ft./sec. over 6" NPS.
All applications when flow turbulence is generated within 10 diameters from the expansion joint.
There are special circumstances involving the use of flow liners:
Standard liners are rigidly attached on the upstream end of the expansion joint and open on the downstream end. If reverse flow conditions exist, the liner thickness must be very heavy gauge or a telescoping design should be used.
If the expansion joint is installed is a vertical run and the flow is upward, drain holes should be added at the lowest point of the liner to avoid trapped liquid.
Unless a special oversize bellows design is used, the flow liner will intrude into the pipe or duct flow path. If the expansion joint motion is axial only this intrusion will be minimal, and the liner inside diameter may be comparable to the adjacent pipe or duct.
If there is lateral or angular motion the gap between the liner outside diameter and the bellows inside diameter must be great enough to allow for this movement as shown in the illustration.
Expansion joints designed for axial compression with flow liners must be designed so that the liner does not extent beyond the end of the joint shown in the illustration.<
Example: 24″ nominal diameter Single fixed flange, Standard bellows material, 304 stainless steel Standard flange material A-36 carbon steel 3.0″ axial compression, 1.5″ axial extension
Operating Conditions: Low Pressure Round Expansion Joints are designed for applications where the pressure including tests does not exceed 15 psig. The design temperature varies with the configuration and materials of construction. Consult the purchase specification for the design temperature and the rated travel of the product purchased. Be certain that the system operating conditions and test conditions do not exceed the rated values.
Guides, Supports, Anchors: Low Pressure Round Expansion Joints are light weight construction. Guides, supports and anchors are important to prevent damage. Refer to the Applications section for the correct locations and design.
Flow Direction: The flow direction can be from either direction for expansion joints that do not include a flow liner. The flow direction for expansion joints with flow liners is from the fixed (welded) end to the free end as indicated on the exterior. Confirm that the joint is oriented correctly.
Shipping Restraints: External restraints are installed at the factory to ensure installation at the correct length and alignment. They are painted yellow and labeled – Shipping bars, remove after installation. Leave these restraints installed until after the installation of the expansion joint is complete – but they must be removed prior to pressure testing and use. CAUTION: Shipping restraints may be installed by welding. Provide protection for the bellows element from cutting or grinding during removal.
Tie Rods: Tie rods, limit rods, and control rods are devices that limit the travel of the expansion joint. They are available as an option on expansion joints. If they are included be certain that the installation allows the design movement of the expansion joint.
Post Installation Inspection
Inspect the expansion joint for damage with close attention to the bellows element.
Is the expansion joint installed at the correct location; are the anchors, guides and supports installed in accordance with the system design?
Are the guides and supports free to allow the movement of the expansion joint?
Is the flow direction correct if a flow liner is installed?
Have the shipping restraints been removed?
The Limited Warranty applies to all expansion joints.
Rectangular Expansion Joints are fabricated to customer specified dimensions with standard convolution profiles, and a variety of corner configurations. Materials of construction range from carbon steel to stainless steel and high nickel alloy steels. Metal rectangular expansion joints are leak tight and typically last 15 years or more.
Rectangular Expansion Joints
Rectangular Expansion Joints are all metal welded construction designed for very low positive and negative pressure applications such as flue ducts, exhaust systems, ventilation systems, fan connections and air supply systems. Since these ducts are sized to meet flow requirements and to mate with mechanical equipment, rectangular expansion joints are designed to match the duct and equipment sizes. They are manufactured with a variety of convolution profiles, corner designs and end attachments. Offers standard convolution profiles and corner designs as well as having the capability to manufacture custom designs.
Rectangular Expansion Joints offer many benefits:
Materials can be any sheet material including Cor-Ten®, austenitic stainless steel alloys 304, 316, 321, 347 and high nickel alloys 600, 625, 800 and 825. Standard Convolution Profiles
The convolution profile can be designed to meet specific requirements; however, the majority of applications can be met with standard designs. We offer two standard profiles which are tailored to the lengths of the sides. These profiles are also ideally suited for the most common corner configurations.
The most commonly used corner configurations are pictured below along with a description of their individual benefits. There are other corner designs such as rounded corners; however, there manufacturing limitations that restrict the depth of the convolutions and as a result have a lower flexibility. Standard Corner Configurations
The most commonly used end attachments are illustrated below. Bolted angle flanges are the most common which have the benefit of stiffening the duct as well ease of installation and removal. As an alternative the flanges can be welded along the outer edges in place of bolting. Although they are not shown plate flanges are sometimes used.
Most rectangular expansion joints are used to absorb thermal expansion as axial travel or as connectors to isolate fans and other mechanical equipment. As a result most configurations are single unrestrained joints. There are no standard sizes since the ducts are individually fabricated and designed to accommodate the system design. Although we can fabricate other convolution profiles, the standard LOCORR and HYCORR profiles will accommodate most sizes, and they can be used with one of corner designs pictured. The end attachments are generally selected to conform with attachments used in the system or to mate with equipment. The most common end attachments are bolted flanges. The flanges have the added benefit of reinforcing the duct work.
We perform a design analysis on all designs in conformance with the method of analysis outlined in the Standards of the Expansion Joint Manufacturers Association, Inc.(EJMA). Rectangular expansion joints have stresses, and angular and lateral spring rates associated with the “long side” and “short side” sometimes referred to as the “easy way” and “hard way” and accordingly must be individually analyzed. In addition to these calculations we can perform an analysis on the duct to determine if internal or external stiffeners are required to react the pressure forces.
Rectangular expansion joints are commonly furnished with flow liners to reduce pressure drop and prevent impingement of the flow on the bellows. The material used is frequently the same as the duct material. Most rectangular expansion joints are used in applications where the ducting is supported and anchored and the joint motion is axial; however, limit rods or tie rods are frequently incorporated into the design to prevent over travel.
Single rectangular metal expansion joints have limited ability to absorb lateral offset or deflection. If lateral offset is a requirement a universal configuration is recommended or two single joints spaced apart. If the motion is limited to one plane, hinges or slotted hinges are frequently included. Slotted hinges have the benefit of stabilizing the
expansion joint, limiting the axial travel and supporting the weight of adjacent ducting. The joint pictured is used in the exhaust stack of a ship. The rounded ends are made from round expansion joints cut in half. This is the same technique is used to made round corners of rectangular expansion joints.
Although not common because of the added complexity, “race track” or “bath tub” joints are sometimes used. The joint pictured is used in the exhaust stack of a ship. The rounded ends are made from round expansion joints cut in half. This is the same technique is used to made round corners of rectangular expansion joints.
Bellows are commonly incorporated into assemblies designed specifically for a customer’s application. Our total capability to design products and to fabricate all of the component parts minimizes development time and provides control over production.
In this paragraph, I’m going to talk about Laminated Bellows Expansion Joints. Firstly they are designed for installations where the principal movement is axial. Secondly standard designs are 2” through 14” NPS with 2” or 3”axial compression. Lastly, service conditions are 150 PSIG or 300 PSIG to 500°F.
Further, the bellows element is put into the design to provide the minimum effective area and resulting pressure thrust. Moreover the laminated construction results in the optimum cycle life and lowest possible spring constant. However, a stainless steel flow liner is standard with little reduction of flow area. Standard joints are available from stock.
Sizes 2″ through 14″ IPS.
Design conditions of full vacuum to 150 and 300 PSIG at 500°F.
Axial travel up to 3.0 inches
Maximum flexibility and extended life
Low spring rates and pressure thrust
Laminated Bellows Expansion Joints
Pipe expansion or contraction resulting from temperature changes is independent of line size; however, the bellows elements of small diameter expansion joints have less ability to absorb motion than larger sizes. Because of restrictions on the corrugation size. Recognizing these shortcomings, Laminated Bellows Expansion Joints for applications that involve axial motion. The bellows elements are designed with up to four individual thicknesses or laminations of precision stainless steel foil. This design combines the high flexibility of thin material while providing the pressure resistance of multiple laminations. As a comparison, a bellow made from four plies of 0.008″ thick material. Will have the same pressure rating as a single thickness of 0.016″ thick. But the laminated construction will deflect twice as much and requires only one-half the force to compress.
The bellow is put on the inside of the pipe. This method has the advantage of providing reinforcement of the bellows neck and attachment weld. Thus reducing the effective area of the bellows and the corresponding pressure thrust. The pressure thrust force of Laminated Bellows Expansion Joints ranges from 40–70% of comparable products.
Laminated Bellows Expansion Joints
All Laminated Bellows Expansion Joints include a stainless steel flow liner. Therefore, the flow liner eliminates added pressure drop resulting from the bellows. Also it protects the bellows from the flow. And as a precaution provides help for the bellow in the event of over-pressurization. They offer the most reliable, yet economical, pipe expansion compensation available. The all-metal welded construction permits service to 500°F for standard models.
Laminated Bellows Expansion Joints are designed for installations where the principal movement is axial. The piping system must include anchors to react the force produced by pressure thrust. Also the pipe alignment needs to be maintained by guides.