This 42″ dia. x 13-3/4″ OAL single expansion joint was refurbished for a chemical plant. The bellows were replaced with 304 stainless steel and the flanges were sand blasted and painted. The expansion joint was designed for a spring rate of 4,253 lb./in., 5/8″ axial movement at 222°F and 50 psig. A dye penetrant examination and air soap and bubble test was conducted prior to shipping.
Single Expansion Joint > Blog Articles
The single flanged metallic expansion joint was manufactured from 304 stainless steel bellows with carbon steel flanges. It has a diameter of 20″ and an overall length of 15″. It will be used in an exhaust duct application in a power plant. A hydro-test was performed prior to shipping to Orlando, Florida.
U.S. Bellows, Inc. recently refurbished a 3″ O.A.L. single bellow with flanges for a marine vessel in Texas. Within a two day span, the replacement bellow was fabricated, welded to the existing 5/8″ flanges, and shipped to the marine vessel to resume operation. The replacement bellow, fabricated from 321 stainless steel, is designed for 150 PSIG and 800° F with 0.66″ of axial movement. To ensure quality, a 100% dye-penetrant test and a soap leak test were performed prior to delivery.
U.S. Bellows, Inc., the expansion joint division of Piping Technology & Products, Inc. rushed to an emergency call of an Alaskan petroleum firm. The firm called upon U.S. Bellows’ 24 x 7 Quick-Turn/Emergency service to aid them in the immediate replacement of a defective, 48″ diameter expansion joint when their G417 Pump failed suddenly during the plant startup.
The timeline of events demonstrates the quick engineering and manufacturing response from U.S Bellows:
07/21/00 (Friday) 5:30 p.m., U.S. Bellows receives an emergency call.
07/22/00 (Saturday) U.S. Bellows/ PT&P builds the 48″ diameter expansion joint and ships it to location on the same day.
07/23/00 (Sunday) The 48″ diameter expansion joint designed and built by U.S. Bellows/PT&P was installed at customer’s location.
The customer expressed great appreciation for the extraordinary efforts put forth by the individuals at U.S. Bellows. The on-call engineering and manufacturing team demonstrated its ability and commitment to servicing customers on an emergency basis.
U.S. Bellows is available on a 24 x 7 basis to fulfill any emergency requirements that might arise in the course of plant shut-downs or start-ups. The company has a system of stock bellows which can be used to assemble and ship different types of expansion joints including universal, elbow pressure balanced, and in-line pressure balanced expansion joints. The U.S. Bellows’ “on-call” engineering and manufacturing team is specifically equipped to handle rush and emergency orders. Using unique web and Internet-based technology, the company is able to respond to any emergency requirements within 30 minutes of notification.
PT&P has acquired the metal expansion joint business of RM Engineered Products, Inc. This acquisition included the design software, drawings, business records and all the equipment used to manufacture metal bellows. The equipment was moved from their plant in Ladson, South Carolina and installed in our new building here in Houston. The move and installation efforts were managed by Rick Thompson who joined PT&P in 1995. Rick will be in charge of manufacturing and fabrication of these products.
How to Make a Simple Bellows
Photo 2 shows a roll of stainless steel next to a shear which is used to cut the starting piece for the bellows. The particular metal required depends on the temperature, pressure and other design parameters for the expansion joint. Table 1 shows the standard metals used and the corresponding ASTM specification.
|Material Type||ASTM Material Specification|
Rectangular pieces are rolled to form a cylinder with an open seam. The automatic TIG flat bed welding machines shown in Photo 3 require only a few minutes to produce a homogenous weld. Proper set-up of the machine is critical to the quality of the weld. One of the capabilities we have added is an x-ray machine to verify the quality of the welds.
The next step is to shape the required convolutions. Convolutions provide the flexibility required and the total movement capacity of the bellows is proportional to the number of convolutions. The convolutions are formed in two steps. The first step produces a v-shaped circular expansion at the center line of each convolution. The second step extends the triangular shape and provides a flat ring shape for the convolution. This entire process is called roll-forming. Photo 4 shows a roll-forming machine. Different size convolutions require varying set-ups. The arms of a machine for much larger units can be seen in the background.
Bellows are the primary “building blocks” for a variety of expansion joints. The spring rate is determined by the size of the convolutions and the metal used. The compression, extension, lateral offset, rotation etc. required for a particular application determines the design required for the entire expansion joint. Photo 5 shows a “wedding cake” machine used to size bellows when fitting them to other components of the expansion joint.