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ASME Tanks
 Tank and vessels manufactured by Chicago Boiler Company can be constructed to a variety of codes and standards. Chicago Boiler Company is an ASME certified manufacture. We manufacture pressure vessels to every aspect of the standard. Code vessels can be supplied for vacuum or pressure service and for use in aggressive environments.
The ASME code (American Society of Mechanical Engineers) is a quality standard assuring the highest quality product that insures safety, reliability and economy. Manufacturing a vessel using the code guidelines, requires multiple reviews and inspections by an independent certified inspector and also it requires the use of materials certified for use as pressure vessel rated material. Most vessels will have three reviews/inspections of the product. These are reviews of the design calculations and material certifications, review and inspections of the initial assembly and finally a witnessed non destructive test prior to shipment of the vessel. All of this insures quality and safety of the vessel for the designed service.
Here at Chicago Boiler Company, we have been fabricating custom ASME code tanks since 1891. If you have questions regarding a tank design, our engineering/design department has solutions to help you comply with standards. They are also available for assistance in making your tank design as cost efficient and functional as possible.
ASME Construction Process
A tank manufactured to ASME standards requires a series of inspections and careful planning.
Even a simple vacuum or pressure rated tank design must follow these strict steps. However following these steps will completely insure the safety and service life of the vessel.
Step 1) Design review
All vessels are designed to meet the latest edition of the ASME Boiler and Pressure Vessel Code, Section VIII Division 1. Engineering calculations are performed to verify or determine the material thickness required for the design pressure and temperature of the vessel. A simple vessel design calculation will examine the circumferential welds, the longitudinal welds, joint design, joint bonding efficiency, type of metal selected, working pressure and the vessel size. If the vessel has openings, the size, type location, and number are also included in the original design review. After this design review is complete, a set of working drawings will be created. All custom tanks will require subsequent review and approval by the purchaser. Since this is a custom product manufactured to meet a specific application, no work will be started until the purchaser agrees to the tank design. Once the design is approved by the purchaser, the next step is fabrication.
Step 2) Fabrication
Fabrication is the term used for creating parts of a metal tank. Flat plate stock is rolled to the required diameter. This diameter is based on the diameter of the tank ends because the tank end diameters can vary slightly in diameter. By checking this diameter, a smooth transition to the tank end can be made. The tank ends (known as heads) are also prepared to be joined to the vessel. All of the openings are then drilled or burned into their locations. This is now the beginning of a basic tank. Once all of these pieces of the tanks have been created, it will then move to the next step which is Fit Up.
Step 3) Fit Up
Fit Up is the initial assembly of the tank. It involves joining together the vessel, heads and major openings. Once these pieces are assembled, work is stopped and the vessel will be inspected by an independent inspection service. The inspection review will look at initial welding, metal to metal contact points and over all construction practice. Once this step is completed, the vessel will move to welding.
Step 4) Welding
The next step to completion of the vessel requires the vessel to be welded by certified welders. Prior to this step, each welder must pass a series of semi-annual qualifying test welds to prove his ability to properly bond the components. Additionally, each step of this procedure from design to fabrication is documented and noted with the individual performing the task. In the case of welding, each welder must sign off indicating the welding function was performed to the best of his or her individual skills and when that function was performed. When the welding step is completed, the next step is a non-destructive evaluation of the vessel.
Step 5) Non-Destructive Testing (NDT)
The non destructive testing of the vessel involves filling the vessel with water and then applying pressure to the vessel. This is the safest most reliable method to discover failures of the welds (pinholes, cracks, and missed welds). If a pinhole is discovered the leak usually drips or in very rare cases water will squirt out of the hole. Testing with water is a preferred method because of water’s resistance to compress and is commonly referred to as hydrostatic testing. A witnessed hydrostatic test is conducted with the independent ASME pressure vessel inspector. Following the witnessed hydrostatic test, a permanently attached label is installed on the vessel, and final paperwork is signed and submitted to the customer and to the National Board of Boiler and Pressure Vessel registers. The internal paperwork procedure is completed and the vessel is prepared for painting and shipping.
Materials
- Stainless Steel Construction
- Carbon Steel Construction
Capacities
- Maximum of 12.5 Foot Diameter; Minimum of 6 inch Diameter
- Maximum of 110 Foot Length; Minimum of 18 inch Length
Additional information regarding Chicago Boiler's tank fabrication can be found in this brochure.
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