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CASE STORY BELLOW WITH PURGE NOZZLES TO AVOID MEDIA SETTLING Belman provided a remarkable Expansion Joint solution for installation in a chemical plant in Europe. CLIENT ISSUE The client needed a replacement Expansion Joint for an existing one that had reached the end of its service life. The client was very satisfied with the design and needed a supplier able to manufacture an identical piece. They therefore turned to Belman, as we specialise in custom solutions and are capable of designing and producing almost any Expansion Joint type, no matter how complex its construction may be. BELMAN SOLUTION In this case, the client had a remarkable Expansion Joint design installed, which involved a bellow with purge nozzles to avoid media settling. Belman’s job here was to design and produce an identical part, which we were happy to do. As this Expansion Joint is installed between a scrubber and a saturator and therefore directly onto the equip- ment, very special flanges were needed. The Expansion Joint has a loose flange at one end and a fixed flange at the other end to ensure a torsion-free installation. The client specified a maximum spring rate, as they wanted to reduce the force transferred to the connected equipment. Due to modern production technologies Belman was able to meet even lower spring rates than those specified, for the benefit of the client. The Expansion Joint is made entirely from material 1.4435 (AISI 316L) at the client’s request due to its low carbon content and its ability to resist intergranular corrosion. The special purge and heating nozzles are made from 1.4301. The flanges are designed with thick walls due to the elevated test pressure. Besides the purge and heating nozzles, the Expansion Joint is also designed with a very special inner sleeve. With purge and heating nozzles to avoid media settling in the bellows The Expansion Joint is installed horizontally. The melamine media, a mixture of NH3/CO2/melamine, can become slightly solid at low tempera- tures. As this mainly becomes an issue at the bottom end of the convolutions, a special inner sleeve construction was made. To facilitate this, three steam purge and heating nozzles were required. By blowing steam into the bottom of the Expansion Joint, the critical areas are heated up, thereby keeping the medium at an acceptable temperature. This is not relevant for the upper area of the Expansion Joint, as the media cannot settle in the convolu- tions here. This prevents the media from settling in the bottom of the convolutions, which would damage the Expansion Joint and prevent it from working as intended. Special transport bars To ensure the Expansion Joint had the correct installation length to fit into the gap in the pipeline upon arrival at the chemical plant, Belman mounted some special transport bars for pre-tensioning during transportation. To avoid welding too many special lugs into the Expan- sion Joint that would offer no use afterwards, special threaded holes were made in the large flange (which only went part-way through) for mounting the transport bars. The special transport bars will be removed after installation. DESIGN PARAMETERS Type: Universal Expansion Joint • Quantity: 1 pc. • Dimensions: DN 600 • Installation length: 1000 mm • Medium: NH3/CO2/Melamine(ANP) • Design pressure: -1/10 barg • Design temperature: 250°C • AX: +0/-16 mm • LA: +26/-0 mm • Bellow and inner sleeve: 1.4435 (AISI 316L) • Flanges and pipe ends: 1.4435 (AISI 316L) • Design code: EN14917
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CASE STORY PRESSURISED EXPANSION BELLOW DURING STORAGE Belman engineered and manufactured a special Expansion Bellow for installation in the compressor lines at a chemical facility in Europe. CLIENT ISSUE The client first contacted Belman in 2021 as they had a broken Pressure Balanced Expansion Joint in their piping system. Belman not only delivered a new Pressure Balanced Expansion Joint solution but also studied the photos and specifications and recommended some design improvements to avoid the problem reoccurring. Now, the client was reaching out to Belman again, as they were looking for a spare Expansion Joint to keep in stock. This will eliminate the need to wait for a new unit once the existing Expansion Joint reaches the end of its service life. BELMAN SOLUTION As the Expansion Joint had to absorb both axial and lateral movements in combination, Belman designed the Inline Pressure Balanced Pipe Expan- sion Joint with two flow bellows at one end. This special design allows the first flow bellow and the balance bellow (the largest bellow) to take up the axial movement together with the flow bellow on the other side of the balance bellow. The flow bellow in the middle then takes up both axial and lateral movement. For lateral movement absorption, it works together with the second working bellow placed at the very end of the Expansion Joint. The Pressure Balanced Pipe Expansion Joint was designed with external limiters to control the Expansion Joint move- ments. Thus, the tie rods are responsi- ble for transmitting the movements from the flow bellows to the balance bellow and vice-versa. Due to high flow velocity, the Pressure Balanced Pipe Expansion Bellow was designed with an inner sleeve to protect the bellows. High flow velocity can result in flow-induced vibrations in the bellow, which can considerably shorten its lifetime or, in worst-case scenarios, cause damage to the Expansion Joint. An inner sleeve can help solve this problem. Expansion Joint kept under pressure during storage As per client request, the Pressure Balanced Pipe Expansion Joint was delivered with blind flanges at each end of the Expansion Joint. Furthermore, it was delivered with seals, bolts, a pressure gauge monitor and a ball valve. Due to the client’s critical need for the unit, they wanted to make sure this spare replacement Expansion Bellow could be used immediately when necessary. The client therefore wanted to keep the Expansion Joint under pressure during storage. The Expansion Joint was delivered with inert gas at a pressure of 0.5 barg. By keeping it under pressure, the intention was to reduce the risk of corrosion on the carbon flanges. By creating a controlled atmosphere inside the unit, the client could also prevent the inside of the Expansion Bellow from corroding. The ball valve was included in the design to release overpressure. In addition, when the client is ready to insert and use the spare Expansion Joint, they can open the ball valve to release the 0.5 barg pressure. They can then simply remove the blind flanges and the Expansion Joint is ready for installation in the pipeline gap intended for it. DESIGN PARAMETERS Type: Inline Pressure Balanced Expansion Joint • Quantity: 1 pc. • Dimensions: DN 350 • Installation length: 985 mm • Medium: Air (ANP) • Design pressure: 18 barg • Design temperature: 140°C • AX: +0/-5 mm • LA: +0/-40 mm • Bellow: 1.4541 (AISI 321) • Inner sleeve: 1.4307 (AISI 304L) • Flanges: 1.0565 (P355NH) • Design code: EN13445
