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SAFETY RECOMMENDATIONS FOR PIPING SYSTEMS CONTAINING BELLOWS EXPANSION JOINTS

Bellows pipe expansion joints are employed in piping systems to absorb differential thermal expansion while containing the system pressure. They are being successfully used in refineries, chemical plants, fossil and nuclear power plants, shipboard applications, heating and cooling systems, pulp and paper plants, and cryogenic plants. Typical service conditions range from pressures of full vacuum to 1,000 psig (70 kg/cm3) and -420F to +1,800 F (-251C to +968 C). Thus, pipe expansion joints must be specified as a highly engineered product. They cannot and should not be purchased and used as commodity items if the pipe expansion joints are to perform their intended function safely and reliably. The system operating requirements, the pipe expansion joint design and manufacturing quality, the installation, test and operating procedures must all be considered for all pipe expansion joint installations.

Unlike most commonly used piping components, a bellows is constructed of relatively thin gauge material in order to provide the flexibility needed to absorb mechanical and thermal movements expected in service. This requires design, manufacturing quality, nondestructive examination, handling, installation and inspection procedures which recognize the unique nature of this product.

In general, the most reliable and safe bellows pipe expansion joint installations have always involved a high degree of understanding between the user and manufacturer. With this basic concept in mind, the following recommendations are given in order to better inform the user of those factors which many years of experience have shown to be essential for the successful installation and performance of piping systems containing bellows pipe expansion joints.

Externally Pressurized X-Flex Expansion Joints for a Overseas Facility

September 14, 2021

Externally Pressurized X-Flex Expansion Joints for a Overseas Facility

“Decarbonation” and “Carbon Neutral” are two key terms used to describe efforts to lower the amount of greenhouse gasses emitted into the atmosphere. Efforts are now underway to gradually convert existing Coal-Fired, HRSG (Heat Recovery Steam Generated or Natural Gas Powered) and other power plants utilizing fossil fuels onto plants that emit far fewer greenhouse gasses into the atmosphere. U.S. Bellows, Inc. received unique specifications to design and manufacture externally pressurized expansion joints for a facility overseas. The bellows are fabricated from 316 stainless steel and all other components are carbon steel. They are designed for a temperature of 200°F at 150 psig with 8″ axial compression. The units are 4″ NOP x 63″ L, 6″ NPS x 61.44″ L, and 12″ NPS x 64″ L.

3d drawing externally pressurized ej 171063Externally pressurized pipe expansion joints, also known as X-Flex expansion joints, are suited for piping systems that require large amounts of axial compression or extension. In externally pressurized pipe expansion joints, the bellows elements are arranged so that the media flow is on the external surface of the bellows. Externally pressurizing the bellows eliminates pressure instability as a limitation to the design and permits the absorption of large amounts of axial expansion. Our QC department conducted various NDT examinations (X-Rays, PMI, Penetrant Tests, and Hydro Tests). Also provided were “weld maps” and MTR’s for client review and inspection. At U.S. Bellows, we are constantly developing and assisting client engineers in this effort toward decarbonation by designing innovative products to accommodate new and unusual design specifications.

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Custom Single Ply X-Flex Bellows Designed for a Manufacturing Company of Flooring Products

August 16, 2021

Custom Single Ply X-Flex Bellows Designed for a Manufacturing Company of Flooring Products

U.S. Bellows customized single-ply X-Flex bellows for the world’s largest manufacturer and supplier of flooring products with locations throughout the U.S. Flooring products such as carpet, ceramic tile, natural stone, laminate, vinyl, and hardwood require many of the same piping systems as traditional indoor plants for the automotive, food processing, semiconductor, textile, and pulp & paper industries. Plants that manufacture flooring are usually quite large requiring large tracks of land. As a result, the “pipe runs” can extend hundreds of feet requiring various types of expansion joints to accommodate the movement of the pipe while also relieving stresses in the piping system. Externally pressurized expansion joints are especially suited for piping systems that require large amounts of axial compression or extension. In externally pressurized pipe expansion joints, the bellows elements are arranged so that the media flow is on the external surface of the bellows. Externally pressurizing the bellows eliminates pressure instability as a limitation to the design and permits the absorption of large amounts of axial expansion. These expansion joints are fabricated with 304 stainless steel bellows, flanges, and pipe. They are designed for 300°F at 14.7 psig with an 8″ extension. The units are 3″ pipe x 40″ long, and 4″ pipe x 40″ long. The expansion joints were hydro-tested and underwent NDE quality control inspection tests such as liquid penetrate inspection (LPI) before shipment.

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Super U-Loop Expansion Joint Designed for a Chilled Water Line

August 1, 2021

Super U-Loop Expansion Joint Designed for a Chilled Water Line for Paint and Body Shops in Automotive Manufacturing Plants

U.S. Bellows, a division of PT&P has developed its Super U-Loop and Super V-Loop product line for applications requiring accommodation of axial growth typically on longer runs of piping. The Super U-Loop and Super V-Loop designs restrain pressure thrust without any anchoring in the piping system. U.S. Bellows is the first company to bring its advanced expansion joint technology used in the world’s most challenging applications to a standard V-Loop and U-Loop product offering. U.S. Bellows expansion joints are used in key process areas in oil and gas, chemical, power, semiconductor, food, automotive, and other operating plants in extreme environments which include temperatures over 1000°F, pressure over 200 PSI, and a wide variety of highly corrosive materials. This particular U-loop shown in the picture below was designed, manufactured, and shipped in less than 9 days from our Houston-based manufacturing facility.

Us bellows universal expansion joint loop 185130 b
Super U-Loop for Automotive Plant – 14” NPS, 4” Axial Movement
Option Super U-Loop Advantages Super U-Loop Disadvantages
Pipe Loop · Super U-Loop requires far less space

· Can be designed to accommodate large amounts of axial movement

· Pipe loop is a lower cost if the space is available
Flexible Metal Hose Based U-Loop and V-Loop · Flow liner protects the interior of the bellows

· Cover on Bellows protects exterior of bellow – Flexible metal hose can be damaged easily by accidental bumping, banging, etc.

· Super U-Loop can be designed with varying thickness to optimize strength versus lower spring rate

· Super U-Loop can be made with custom metals to accommodate environmental conditions – includes Hastelloy, Inconel, Monel, …

· Designed to better withstand vibration in Piping System

· Standard designs can be delivered in as little as 1 week

· Flexible metal hose offers a very low spring rate

U.S. Bellows/PT&P’s Super U-Loop and Super V-Loop offer a breakthrough option for accommodating large amounts of axial growth in both commercial and high-temperature industrial environments. The traditional option used when space was not available for a pipe loop was a flexible metal hose which introduced the risk of failure into the piping system. U.S. Bellows design is built around minimizing the risk of failure by:

  • Flow Liner – protects the interior of the Bellows
  • Cover – protects the exterior of the Bellows for damage such as falling wrenches, accidental banging by a forklift, etc.
  • Limits Excessive Cycling – if vibration in the piping system “cycles”, a flexible metal hose may not be an adequate solution. The reason is that neither expansion joints nor flexible metal hoses are designed to support millions of cycles. The low spring rate of the flexible metal hose makes it more vulnerable to being cycled by unintended continuous vibration in the piping system. Even 1 Hz of vibration rapidly leads to excessive cycling with 86,400 cycles per day. By incorporating either a Super U-Loop or Super V-Loop with an expansion joint, we are able to accommodate a large amount of movement with the ability to dampen vibration due to the higher spring rate of the expansion joint design.

Us bellows universal expansion joint loop 185130 c

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Universal Expansion Joints Custom-Designed for a Hot Air Blower

July 12, 2021

Universal Expansion Joints Custom-Designed for a Hot Air Blower

These universal expansion joints were custom-designed with guided tie rods, internal liners, and bellows protection covers for a hot air blower. These expansion joints are used in a plant that manufactures tires for cars and light-duty trucks. High Heat is required in the manufacturing process to vulcanize rubber to components made of steel and polyester and to also cure the rubber. The universal expansion joint can allow for large amounts of lateral deflection that can occur in more than one plane. By increasing or decreasing the distance between the two bellows by varying the length of a section of pipe spool, the designer can accommodate for the given amount of lateral deflection. These expansion joints are designed for an operating pressure of 50 psig at 383 degrees F. A total of 18 were supplied with half of the units measuring 40” dia. x 74-7/8” long x 58-1/2” overall outer dia. The rest measure 36” dia. X 60-1/4” long x 53-3/4” overall outer diameter. The bellows, flange, middle pipe, liner, and lugs are fabricated from 316/316L stainless steel. The rods, nuts, and cover are 316 stainless steel. The 40” dia. unit is designed for 0.394” axial compression and the 36” dia. unit is designed for 0.20” axial compression. Both units are designed for 0.394” lateral movement. Each expansion joint was inspected by quality control and hydraulic pressure tested before shipment. We manufacture expansion joints to relieve stress in piping systems whether the thermal movement is axial, lateral, or angular in plants such as Food Processing, Automotive, Hospital Steam Lines, Semiconductors, and other types of Green Energy plants.

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Rubber Expansion Joints for a 24″ Dia. Pipeline at an Offshore Production Facility

June 14, 2021

Rubber Expansion Joints for a 24" Dia. Pipeline at an Offshore Production Facility

U.S. Bellows provided rubber expansion joints for a 24” diameter pipeline at an offshore production facility. Used near rotating equipment such as pumps and compressors, rubber expansion joints provide a viable alternative when metal joints cannot be used. Expansion joints can be used in plants such as biofuels green energy that utilize trash/waste as feedstock help to reduce greenhouse gas emissions. The retaining rings are fabricated from A240-316 stainless steel. The expansion joints are 28-1/8” O.D. x 24” long. Each unit was hydro pressure tested and inspected prior to shipping overseas. U.S. Bellows can provide rubber expansion joints up to 144” in diameter or higher for custom applications. Rubber pipe expansion joints are often used to compensate for minor misalignment and offset. The design is chemical and abrasion resistant while limiting sediment buildup. They have an integrally flanged design where no gaskets are required and are designed to absorb noise, vibration, and shock. This single, wide arch, spool-type rubber expansion joint is used to accommodate thermal growth while relieving piping stress during operation. This is just one of many types of rubber expansion joints we can provide to meet your specifications. If needed, using stress analysis, our experienced expansion joint engineers can assist in the design and development of expansion joints for your application.

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Thick Wall Expansion Joints for Large Diameter Piping in a Heat Exchanger

May 12, 2021

Thick Wall Expansion Joints for Large Diameter Piping in a Heat Exchanger

U.S. Bellows, Inc. custom-designed thick wall flanged and flued head expansion joints for large diameter piping in a heat exchanger application. The expansion joints, including the liners, are fabricated from 316 stainless steel. The first unit is 60″ O.D. x 84″ O.D., the second unit is 36″ O.D. x 60″, and both units have a 1/4″ nominal thickness. They were designed for 4.4 psig at 210°F with a 122″ water column. A dye penetrant exam on the circumferential welds was conducted prior to shipping.

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U.S. Bellows Designed an Expansion Joint & Duct Work Assembly during a Plant Turnaround

April 26, 2021

U.S. Bellows Designed a 60" Diameter Universal Expansion Joint & Duct Work Assembly during a Chemical Plant Turnaround

U.S. Bellows designed a universal expansion joint and duct work assembly for a 3rd pass outlet converter to economizer duct work application at a chemical plant in 8 weeks. Expansion joints are used in many economizer ductwork applications near boilers. Plant turnarounds are a vital part of a plant’s maintenance program. They involve a scheduled stoppage of part or all of a plant’s operations. During this time, existing equipment such as expansion joints are removed and replaced with new or upgraded expansion joints. On-time delivery is critical to the plant turnaround schedule in order to limit the amount of time the plant is in shutdown. The total assembly included a universal expansion joint, over 125 feet of custom-built 60” diameter duct work, including elbows, tees, saddles, nozzles, and spring supports. The expansion joints were designed for 0.3 degrees angular movement, 2.875″ lateral, and 3.25″ axial extension. The design conditions were 5 psig at 890 degrees F. The liner, cover, and ducting are fabricated from 304 stainless steel and the bellows are 321 SS. A dye penetrant exam, soap & air test, and spot x-ray on all duct seam welds were performed before shipping. U.S. Bellows has worked extensively on boiler units within the chemical industry and has provided products and designed supports for the unique requirements of economizers including the use of stainless steel and super alloys to support applications such as this involving highly corrosive media.

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78” Dia. Universal Expansion Joint Custom-Designed for One of the Oldest Scientific Innovators in the Engineering Industry

March 29, 2021

78” Dia. Universal Expansion Joint Custom-Designed for One of the Oldest Scientific Innovators in the Engineering Industry

U.S. Bellows, Inc. custom-designed universal expansion joints for one of the oldest scientific innovators in the engineering industry. Large diameter steam pipelines are a part of almost every plant and are associated with innovations in areas like nanotechnology, fuel cells, biomaterials from renewable resources, materials for personal protections (which have been especially important in the time of COVID), emerging video display technologies, and semiconductors. These plants manufacture polymers such as neoprene, nylon, chlorofluorocarbons, synthetic pigments. In this case, the universal expansion joint bellows and liner are fabricated from A240 Gr. 321, the pipe, tie rods, and flanges are fabricated from A240 Gr. 304 stainless steel. They are designed for low pressure (8 PSI) and range from 36” pipe x 60” long up to 78” pipe x 117” long. Per our QC requirements and/or client specifications, the expansion joints were dye-penetrate examined and soap, air bubble tested prior to shipment.

Us bellows universal expansion joint 137373 fab sm
78″ Universal Expansion Joint in Fabrication
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Pressure Balanced Tee Universal Expansion Joint for a Boiler Feed Pump Turbine Exhaust

March 2, 2021

Pressure Balanced Tee Universal Expansion Joint for a Boiler Feed Pump Turbine Exhaust

U.S. Bellows, Inc. custom-designed a pressure balanced tee universal expansion joint for a boiler feed pump turbine exhaust. The expansion joint is 96” diameter and 288” OAL and is designed for 2″ axial movement at 315°F and 15 psig. The bellows, liner, and turning vanes are 304 stainless steel. The remainder of the assembly is fabricated from carbon steel. The expansion joint was dye penetrant examined, and a chemical cleaning of the interior surfaces was performed to remove any oil and grease. U.S. Bellows also conducted a stress analysis and a pneumatic test at 23 psig.

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U.S. Bellows Custom-Designed Tied Universal Expansion Joints for Service at a Chemical Plant

February 9, 2021

U.S. Bellows Custom-Designed Tied Universal Expansion Joints for Service at a Chemical Plant.

Universal expansion joints such as these are used in chemical plants that manufacture petrochemicals (such as ethylene and styrene monomer), polymers, and building products (PVC profiles for windows, doors, and decking). The units range from 26” to 48” in length and 8” to 20” in diameter. The bellows were fabricated from 321 stainless steel, the weld ends, pipe spools, and flanges from 304 stainless steel, and the tie rods and hex nuts from carbon steel. They are designed for temperatures ranging from -150°F to 800°F, operating pressures ranging from 50 to 240 psig, and 0.25” to 2.25” of lateral deflection. The expansion joints were air, soap, and bubble tested, 100% dye-penetrant tested and hydro-tested before shipment. The universal pipe expansion joint consists of two bellows separated by a pipe section or spool. The primary purpose of this arrangement is to have a unit that will accept large amounts of lateral deflection. The amount of lateral deflection they can accept is a function of the amount of angulation each bellows can absorb and the distance between the bellows. For a given bellows element, the amount of lateral deflection capability can be increased or decreased by simply changing the length of the center spool.

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