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Expansion Tanks

A reliable source for Expansion Tanks information and leading Expansion Tanks Companies & Manufacturers.

Modern tanks are called diaphragm expansion tanks and are attached and hang down from the boiler piping on the supply side of the system. Older models were larger, horizontal and connected from above the system. Read More…

Expansion Tanks Expansion tanks are small vessels containing pressurized air that are components of closed water heating systems for both residential and commercial buildings.
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Leading Manufacturers

Oak Lawn, IL  |  800-282-1574

If you are looking for innovative pressure vessels, you’ve come to the right place! We actively manage your project every step of the way. We keep you informed of what we are doing to ensure we keep up to your standards and delivery times.

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Midwest Imperial Steel Fabricators, LLC $$$

Gladwin, MI  |  989-426-4768

Gladwin Tank Manufacturing specializes in custom designed and built ASME tanks and ASME jacketed weldments of any shape or size made from carbon steel, stainless, duplex and nickel alloys.

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Gladwin Tank Mfg., Inc. $$$

West Alexandria, OH  |  937-307-3597

Rexarc’s focus is on the fabrication of custom stainless and carbon steel pressure vessels. We welcome applications with pressures between 500 and 5,000 psi. After nearly 100-years of being in business, Rexarc has the knowledge, attitude, equipment, and processes to support your needs in vessel production and value add services of piping, instrumentation, paint, and other controls integration. Rexarc’s traditions of customization, communication, and commitment to on-time delivery of products has been passed down through four generations of family leadership. Our customers know that we were here yesterday, we are here today, and we will be here tomorrow.

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Rexarc International $$$

Springfield, MO  |  417-459-9906

Sho-Me Fabrication, LLC is a Missouri based pressure vessels manufacturer. We are a leading and trusted manufacturer, providing the best service and products in the industry. Our highly skilled and experienced workers have quick turnaround with high quality products. Sho-Me Fabrication is able to fabricate your customized product on site or in our facilities. Contact us to see how we can customize a product to fit your needs.

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Sho-Me Fabrication, LLC $$$

Big Lake, MN  |  763-263-0747

Midwest Tank Company has provided quality tanks to small and large corporations and contractors since 1972. Our reputation is built on exceptional services and customer satisfaction! Our fabrication techniques have been developed through years of tank specialization, combined with personnel who are experienced in all phases of our operation.

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Midwest Tank Company $$$

Rockland, ME  |  207-596-0061

Steel-Pro Incorporated has been serving the industry since 1978. As a major manufacturer of quality tanks, vessels and equipment, we are located in the North-East with competitive prices throughout the United States. With over 45 years of experience, we perform every aspect of the process to the highest standards.

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Steel-Pro Incorporated $$$

Humble, TX  |  281-821-0543

Since 1981, Gulf Coast Alloy Welding has been a well-known and trusted leader in the pressure vessels industry. We attribute our success to our years of experience and our highly skilled, quality-driven workers. Our pressure vessels have wall thicknesses up to 8” and can handle pressure up to 15,000 PSI. We strive to have the highest quality products in the industry while continuously improving and expanding.

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Gulf Coast Alloy Welding, Inc. $$$
placeholder image Midwest Imperial Steel Fabricators, LLC Gladwin Tank Mfg., Inc. Rexarc International Sho-Me Fabrication, LLC Midwest Tank Company Steel-Pro Incorporated Gulf Coast Alloy Welding, Inc.

Expansion tanks are easy to maintain, and if they are pre-charged, these tanks are literally maintenance free. All repairs should be done by a certified plumber. These pressure tanks ensure constant pressure within the piping system, and act as a safety device. Without them, the boiler may explode, the pipes could burst and overflowing is a major concern.

They are typically composed of a stainless steel tank, blue or green exterior paint and a rubber spacer called a diaphragm located on the inside of the tank. This diaphragm provides an air-tight seal and divides the tank in half-the bottom is pressurized air, while the top is left open for excess water from the boiler.

Plasite Lined Tank Expansion Tanks - Gladwin Tank Mfg., Inc.

Since they occasionally hold drinking water, expansion tanks, like boilers or other food processing tanks and water pressure tanks, must be sanitary, non-contaminating and conform to health standards. The interior walls of the tanks need to be smooth and groove free. Besides domestic and commercial closed heating systems, most vehicles contain smaller expansion tanks for their heating systems.

The purpose of expansion tanks is to absorb excess water pressure in a closed water heating system. Any water heated in a closed space will expand. Therefore, heating systems need additional space for the increased water volume when it is at a high temperature. The excess water enters the expansion tank, which is filled halfway with pressurized air at 12 psi and divided by a rubber diaphragm spacer.

While the water volume is up, the extra water fills the tank. The top half of the tank is directly connected with the heating system, and when the temperature decreases, the pressurized air on the bottom half of the expansion tank pushes the water back into the boiler system. This ensures there will be no pipe damage because of too much pressure.

Water heating systems without expansion tanks risk the internal boiler pressure increasing beyond the release setting of the pressure release valve (PRV). When the PRV opens, the water leaves the system and creates pressure that is too low. Expansion tanks are always properly charged with air, which shouldn't exceed 12 psi, or the water will boil and this consistency is a major benefit to using expansion tanks.

Expansion Tanks Informational Video

 

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