What is it that allowed us to make a breakthrough in the well-tapped market of heat exchangers?

  • We have created the ribbed sheet panel, the heat exchanger element that provides powerful capabilities both in terms of heat exchange efficiency and in terms of design and technology features.
  • We have created the unique, highly efficient technology for manufacturing such elements with high-frequency welding.
  • We have created the basic (conceptual) design of gas-liquid ribbed sheet heat exchangers.

Fig. 1. Ribbed sheet panel.

The panel is essentially a thin-walled flat sheet with vertical ribs welded onto it.

Manufacturing ribbed panels using high-frequency welding

The advantages of the ribbed panels manufactured using HF-welding:

  1. Minimizing the panel mass allows for lower cost and simpler manufacturing, installation and maintenance of the heat exchanger.
  2. Extensive surface of the ribbed panel (2-3 times more than the traditional panel).
  3. Channel straightness ensures low aerodynamic drag, easy cleaning, minimal slagging.
  4. The panel design provides high strength combined with minimum metal content.
  5. Easily created flow turbulence and high heat exchange coefficient.

So, it is owing to high-frequency welding and the creation of the efficient heat exchange element that the new type of heat exchangers, ribbed sheet panel and gas-liquid ribbed sheet panel heat exchangers (OPT and VP-OPT) appeared. It is impossible to manufacture such products of acceptable quality and efficiency using the traditional welding methods.

It is impossible to manufacture such products of acceptable quality and efficiency using the traditional welding methods. These methods (namely the electric arc welding, semi-automatic welding, argon welding, laser welding and others) used on thin-walled alloy steel (stainless, heat resistant steel) result in low quality products. Combined with the disparately low efficiency of the traditional processes, this renders manufacturing large heat exchangers using the traditional methods either impossible or economically impractical.

The unacceptably low quality of thin-walled panels manufactured using the traditional fuse welding methods stem from the following factors:

  1. In the traditional fuse welding, the formation of the welding seam is accompanied by complex liquid and solid diffusion processes. These processes cause the chemical composition to change in some areas, with isolation and repartition of impurities and alloying elements (liquation). Among other things, the welding seam can lose its corrosion characteristics (a well-known effect is the appearance of corrosion on a stainless steel welding seam), depleted of the relevant alloy elements, and the heat affected area where these elements are transferred, becomes brittle and prone to intercrystalline corrosion and other defects.
  2. Welding seams chemical inhomogeneity can also be caused by insufficient technological culture of the works or the physical nature of the welding seam formation when using traditional welding methods.
  3. These welding processes are not very stable, and besides, the result is affected by the human factor (the welding quality is different in different parts of the welding seam).
  4. The ductility of fuse welded seams is quite low, determined by the duration of welding and the significant heat emission (grain growth), which leads to fast breakdown of the heat exchanger of the heat exchanger due to heat stress.

In welding thin alloy steel elements, that are usually used in ribbed sheet heat exchangers and gas-liquid ribbed sheet heat exchangers, the above factors cause poor quality spots, through faults (through cracks, through corrosion of the walls separating the heat exchange sections), which all results in leaks between heat exchange sections.

However, these defects are not found in high-frequency welding, which is due to the following:

  1. Fast welding, up to 50 m/min (60-100 times faster than traditional welding), combined with local heating for welding significantly reduces alloy element liquation and provides weld ductility.
  2. In the welding zone, there is practically no liquid phase (liquid metal is ejected by the electromagnetic field). As a result, the surfaces connected in welding are absolutely pure, hence no crystallization or its negative effects.
  3. The quality of the welding seam is stable throughout its length (any length).

As a result, high-frequency welding provides quality back-to-back welding seams on thin-walled metal and thermoplastic seams for OPT heat exchanger and VP-OPT heat exchanger operation in any temperature settings (no fractures even in high temperature settings).

Our equipment is used by: