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All-Welded Plate

Schmidt® SIGMAWIG All-Welded Plate Heat Exchangers

Our line of Schmidt SIGMAWIG all-welded plate heat exchangers represents the most compact, rugged and cost-effective means of transferring heat in many industrial applications.

Built entirely without gaskets or with an O-ring type gasket between the all-welded plate pack and frame, they provide exceptional corrosion resistance. The exchanger features corrugated plates that produce highly turbulent flow in a true counter-current direction. The result is high efficiency in a very compact design. Due to the smaller size and reduced material content, welded plate heat exchangers can be the most economical heat transfer choice.

Operating Parameters



-40°F - 570°F (-40°C - 300°C)
Vacuum to 580psig (35bar)
up to 1600 GPM (450m³/h)
1" to 6" studded or flanged

Technical Parameters



AISI 304 Stainless Steel (1.4301) 
AISI 316L Stainless Steel (1.4404)



AISI 904L Stainless Steel (1.4539)
SMO 254
Nickel Alloy, Ti, and Ti-Pd Alloy



0.6 mm


Painted Carbon Steel, or Stainless Steel



AISI 316TI (1.4571)



Nickel alloys, Titanium

Codes and Standards



Reduced Liquid Volume

The standard design has all piping connections located on one end of the heat exchangers. This simplifies installation and maintenance costs. Many times, the piping alone is all that is required to adequately support the heat exchanger, thus eliminating support considerations and labor costs in packaged equipment.

API Heat Transfer welded plate heat exchangers have narrow flow channels and reduced liquid volume needs. Due to their efficiency, they can be selected to use less coolant.

Reliable Heavy-Duty Construction

The exchanger design features plates with computer-designed corrugations in a "chevron pattern" that is alternated from plate to plate. This yields a strong, unitized construction. There are two options for incorporating the welded plate pack into the pressure frame. The plate pack openings are joined to the nozzles of the pressure frame or for frequent temperature fluctuation. The sealing between plate pack and pressure frame is ensured by a standard O-ring sealing material like EPDM or by a special high resistant material like Viton or Kalrez. Gaskets common to other technologies are eliminated.


  • Process chemicals
  • Oil cooling
  • Amine cycles
  • Caustic soda
  • Heat transfer fluids
  • Hazardous liquids
  • Expensive fluids
  • Refrigeration
  • Reactor cooling/heating