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TCM Air-Cell

Built specifically for the electrical transformer industry

About the TCM Air-Cell

The Transformer Conservator Membrane (TCM) Air-Cell flexible separator is specifically engineered for the electrical transformer industry. The TCM Air-cell acts as a barrier to separate undesirable elements in the atmosphere, such as water vapor, nitrogen, ozone and oxygen, from transformer oil within a conservator. This barrier also reduces condensation and oxidation inside the transformer and suppresses gas bubble formation in the transformer oil.

SEI custom fabricates each TCM Air-Cell, also called a transformer conservator bladder, to be used inside cylindrical, elliptical, octagonal or rectangular-shaped conservator tanks. The TCM Air-Cell floats in oil inside the conservator and expands/contracts by breathing through a flange placed in a customer-specified location, thus allowing the TCM Air-Cell to compensate for oil displacement due to temperature variations in the transformer.

SEI specializes in quick delivery for custom TCM Air-Cells to meet the demands of field service operators. When required, SEI can engineer and manufacture a new Air-Cell in as little as 24 hours from an approved drawing or damaged tank. All SEI TCM Air Cells enable sealed conservator insulating liquid preservation systems to meet IEEE Std C57.12.00-2010 6.6.2.

Comparison Chart

Fabric Conservator Air-Cell Oil-Filled, Inert Gas Preservation
Lower annual maintenance System must be monitored more closely.
Lower operational costs. System must be topped up each year.
More reliable for remote or unmanned locations. If no monitoring, must be manually inspected.
Better operational temperature ranges More temperature sensitive
Fungicide can be added No need for fungicide
More labor intensive to install Usually comes fully assembled
Less likelihood of oil contamination Higher likelihood of oil contamination










Custom Construction

TCM Air-Cells are constructed from Temp-Shield™ 30 oz. (1017 g) urethane elastomer-coated nylon fabric that has been specifically designed to be compatible with transformer oils, silicon fluids and bio-degradable transformer oils. The fabric is highly abrasion-resistant and is extremely flexible, ensuring a long-term airtight barrier.

Temp-Shield™ has a high temperature resistance (up to 130 degrees Celsius) and can be used in extreme low temperature settings up to -50 degrees Celsius. Temp-Shield’s nylon substrate also stretches, offering protection against over pressurization or vacuum during installation.



  • SEI offers a selection of standard size transformer conservator bladders to meet a variety of conservator oil volume levels. SEI can also design and manufacture TCM Air-Cells to exact conservator tank size specifications and oil volume levels.
  • All seams are radio frequency welded and seam sealed then tested to ensure seam strength and a long-term airtight barrier.
  • A flange is inserted into each TCM Air-Cell. The flange provides a point of entry allowing the TCM to act as a breather. Flanges can be located anywhere on the Air-Cell to match conservator tank design and SEI offers a variety of standard aluminum flanges.
  • Since the insulating oil is completely isolated from the surrounding atmosphere, there is no possibility of oxygen or moisture getting inside the TCM.
  • The TCM maintains constant pressure on the surface of the oil which, in turn, prevents the oil from becoming supersaturated and forming bubbles. As a result, high dielectric strength can be maintained.
  • Each TCM Air-Cell comes complete with hoops or handles that are used during deployment. These handles are also used to secure the Air-Cell to the conservator tank. SEI will place the handles according to the conservator tank design.
  • Reinforced patches are placed around the flange, handles and at the point of contact with the level indicator to provide extra wear protection.
  • Each TCM Air-Cell is individually marked for identification to enable easy inventory tracking.
  • SEI can design and fabricate custom flanges to meet specific conservator tank designs.
  • SEI can offer alternate handles or securing tabs to meet bar or hook conservator tank attachment points.


Category Numbers

  • Dun & Bradstreet (DUNS): 24-313-6116
  • Cage Code: 0CAE9
  • Procurement Business No (PBN): 104774930 PG0001
  • United Nations: 3226

Product Information

  • SEI Industries TCM Air-Cell


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