The technical fabric compensators (TFC) have proved successful in the equipment transporting gas agents at temperatures up to +1200 °C and pressures up to 0,1 MPa (gauge pressure 1 bar), in ducts having large axial movements with often occurring lateral and/or angular movements.

Such operating conditions can be found mainly in:

  • thermal power plants (with the coal-, oil- or gas-fired boilers), nuclear power plants,

  • natural gas combustion turbines,

  • chemical plants,

  • denitrification (DENOX) and desulphurisation equipment,

  • waste incinerators and flue gas treatment plants,

  • oil refineries, petrochemical equipment,

  • cement kilns and lime kilns,

  • pulp and paper industry,

  • metallurgical works and facilities with industrial furnaces,

  • air-conditioning, dust exhausting and filtering equipment,

  • lacquer paint shops and dryers,

  • industrial stacks constructions, and practically in any ducts through which hot gaseous agents are being transported.

It should be noted that the TFC, as compared to metal sheet or rubber compensator, should find better use in those applications, where there are large and complex movements of pipes installed inside the buildings with relatively small internal space.

The dimensions and conditions for deployment of the TFC in industrial installations are individual like are the pipeline systems and the wishes of particular customer. Therefore, it is not feasible to offer standardized "catalogue + tables" TFC solutions, and any TFC solution has to be customized to the existing basic constructions at the customer´s site.

Each TFC unit usually consists of several layers. There are sealing films, layers of carrier fabric which can sustain thermal and mechanical stress. All components and materials contain no asbestos as a matter of principle. In majority of cases the individual layers are not mutually connected inside the bellows (they are not glued or sewn together). However, the individual layers are joined together at their clamping edges because of transport reasons.

The dimensions and geometrical shape, the material composition and succession of individual layers are designed individually in each application case. The key assumption for an optimum TFC design is the set of precise technical data provided by the customer, the designer or engineer any of those, who are supposed to know well their own equipment.

And this is also our most important task - to acquire as much as information as possible about the equipment operating conditions which enables us to elaborate supply offer of high quality and to manufacture suitable TFC units. In addition to our rich experience with the old type compensators which usually have to be retrofitted, the following criteria are considered during the design stage of each new TFC:

  • original composition of materials,

  • possible causes of damages,

  • equipment operating parameters - operation in base-load regime or the equipment being switched daily on and out,

  • occasional problems with the steel parts located in the TFC - steel pipe joint area,

  • external factors which were neglected during the design stage of the former compensator, whose effect was noticed only after commissioning of the equipment.

The main criteria which are necessary for the design of the suitable compensator are listed hereunder. The knowledge of these criteria shall help to solve the problem and it should help to develop quick and optimum engineering and constructional solutions.

 Selection and dimensioning criteria

  • installation site:
    Indoor / outdoor installation, accessibility of the installation site and / or the respective location for
    maintenance and inspection of particular TFC.

  • type of transported agent:
    This parameter is important to select the suitable composition of materials from which the soft TFC is manufactured, whereby the data on casual surpassing of dew point (origin of condensate) and the effect of the chemical substances (chemical analysis of the transported agent should be included) largely facilitate and effectuate the constructional design and technical solution of encountered problems.

  • transported agent mass particles contents:
    This parameter essentially affects the composition (type and thickness of the surface finish) of the material used for the TFC manufactured as well as its construction and/or the respective steel parts/ guiding steel plates, whereby the key importance is assigned to the data on the mass particles contained in transported agent - mass concentration [mg/ Nm3], size distribution of particles and the direction of flow [upwards, downwards].

  • temperature:
    Likewise as the type of transported gas agent affects the choice of materials used for the TFC, the exact data on operating temperature, outdoor temperature, temperature on the TFC surface and on the TFC edges clamped on the solid duct and the emergency temperature limit, allow us to design the right materials and construction which is customized to the actual needs without superfluous and uneconomical over dimensioning.

  • pressure:
    The exact data on operating pressure - overpressure/ under pressure (normal, maximum value), pressure deviations, pressure surges, testing pressure - allow the engineer to select the right type of construction with the correct dimensions.

  • movements:
    Specification of the movement type (axial, lateral or angular), the movement amplitude and frequency affects not only the constructional design of the compensator, but it also determines the necessary mounting dimensions, therefore an increased attention should be paid to specification of these data.

  • flow rate of transported agent:
    The gas flow rate determines not only the type materials selected for the manufactured compensators, but it also determines the type of the metal parts used in the TFC construction. Anyway, by the flow rates above 10 m/S we recommend to use the guiding metal sheet plate or internal shielding tube to protect the soft compensator parts, to reduce the gas pressure drop and to eliminate unwanted flow turbulence.