Equipment for local and volumetric PWHT (heat treatment of welded joints)

Ways of heaters and thermal insulation fixing

25.09.2018 12:49:00

Different methods are used for fixing heating elements and thermal insulation on the surface of pipelines and vessels.

The most common is fastening the heateing elements with banding strap. The heaters are pre-fastened fith elastic straps. The final fastening of the heating mats is carried out with a banding strap using a special tools and clamps. In this case it is recommended to install at least three belts of the banding strap on each belt of heating elements: one belt belt at both sides of the heating mat and one at the level of the white beads at the ends of the heaters at the place of welding the “cold end” to the “hot” body.

Ideally we recommend using the fourth belt, fixing the zone in front of the detachable connections, as shown in the figure. It is necessary to avoid sagging which can lead to the stress state.

Fastening heating elements with banding strap

Fastening with a banding strap has a number of indisputable advantages over other types of fasteners:

  • lower price in comparison with other types of fasteners;
  • extended service life due to the use of stainless steel materials;
  • extreme simplicity and convenience in the installation process;
  • thanks to the original design, the need to purchase bolts, nuts and washers, keys of various sizes is eliminated;
  • the banding tool has a long exploitation life.

In places where standard use of banding tape for fixing heating elements and thermal insulation is not possible, for example, heat treating the ends of a tube sheet or a vertical surface, we offer another method of fixing heating elements using insulation pins that are welded to the surface with a capacitor discharge by special machines.

Fastening heating elements and thermal insulation with insulation pins

Insulating pin has a special shape that provides reliable fixation with shallow welding of metal. This technology has proven itself in the heat treatment of large-diameter products. Fastening occurs through a hole in the heating element bead. After welding, the heating element is fixed with a special clip.

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