Non-metallic flexible expansion joint

TOMBO™ No. 9999-NA


NA BELLOW-Q is a non-metallic flexible expansion joint that combines inorganic fiber cloth and PTFE and is used for various pipes and smoke airways such as ducts. It absorbs expansion and contraction, deformation, and movement from the heat swelling, vibrations, and pressure of large-diameter ducts and pipes.

Product Category

Gaskets & Gland PackingSemi-Metal GasketsOther ProductsExpansion Joints


Chemistry & PetrochemistryOil Refining & PetrochemistryChemistryEnergy (Electricity, Gas, Heat Supplies)Thermal Power Stations (Coal)Thermal Power Stations (LNG)Nuclear Power StationsHydrogen and AmmoniaBiomass Power Generation and Heat Supply PlantsIron & Non-Ferrous MetalsSteelmaking Plants


The inorganic fiber cloth used for NA BELLOW-Q has excellent heat resistance. It is a strong cloth with excellent flexibility.
NA BELLOW-Q, which is made from these materials, performs excellently as a non-metallic flexible expansion joint.
It has a low reactive force and enables the easy designing of ducts.
It can be manufactured without dimensional restrictions.
It is lightweight and easy to handle.
It offers excellent corrosion and heat resistance.
Steel structure materials can be used for the holding plate.
It has low fluid resistance.
The adhesive offers excellent weather resistance.
It shortens the duration of work.
It offers good value for money.


The NA BELLOW-Q structure is, as shown in the figure below, made up of the bellow unit for absorbing the stretching displacement, a retainer plate for fixing to the duct, set bolts and nuts for adjusting both surfaces, and a sleeve for preventing wear.
The installation structure of BELLOW-Q has two types: a flare type and a belt type. The flare type is indicated with an F and the belt type is indicated with a B.
The flare type is subject to flare processing on both ends. The part that comes into contact with the fluid consists of bellows, and so the flare type is lighter than the belt type and the area between the surfaces can be made smaller.
The belt type is suitable for hot-temperature applications where it is also used with an insulation blanket. Meanwhile, as its structure allows for easy installation, it is also useful for repairing existing metal bellows.

*For NAQ-099, as well as the standard product, Nichias also offers products with custom-designed structures.


The figures below show the various compositions of NA BELLOW-Q. Inorganic fibrous cloth, which is used as a material cloth for bellows, is a thick woven fabric woven from bulky special inorganic fiber yarn and is a material with high strength and flexibility.
Based on the basic structure of NAQ-025, which uses a PTFE film as a sealing layer, Nichias offers NAQ-025P, which uses a protective fabric for the inside of the sealing layer, and a type that also uses heat-insulation material for the bellows. Nichias also offers custom-designed structures (NAQ-099) to suit your usage conditions.


  • TOMBO is a registered trademark or trademark of NICHIAS Corporation.
  • Name of products with "®" are registered trademarks of NICHIAS Corporation.
  • Name of products with "™" are trademarks of NICHIAS Corporation.
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