Plate and Frame Heat Exchanger

Plate and Frame is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids are spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change.

Isotherm Inc. stands out as a leading manufacturer of chevron plate heat exchangers. Their expertise extends to designing plate and frame heat exchangers for diverse applications, including refrigeration. Isotherm prioritizes achieving optimal performance in all their products.

This commitment to excellence is driven by decades of research and development in plate and frame heat exchanger technology, spearheaded by Isotherm’s founder, Dr. Zahid Ayub. Dr. Ayub’s pioneering work (1) and patents (2) have been instrumental in achieving the superior heat transfer efficiency that Isotherm’s heat exchangers are known for.

Various aspects of plates such as Chevron Angle, Pitch and Depth are carefully designed for high Thermal Performance with low Pumping requirements.

Available Types

  • Gasketed
  • Laser Welded Cassette
  • Fully welded
  • Brazed – Copper and/ Or Nickel

Desing Considerations:

  • Gasketed:
    • Easier to clean and maintain due to removable plates.
    • Offer greater flexibility as you can add or remove plates to adjust the heat transfer capacity.
    • Generally preferred for applications with lower pressures and temperatures, or those involving fluids that require regular cleaning.
  • Welded:
    • More robust and can handle higher pressures and temperatures due to the stronger welded joints.
    • Less prone to leaks as there are no gaskets to degrade over time.
    • Often a good choice for harsh environments or applications involving corrosive fluids like Ammonia refrigeration.

Material of construction

  • Plates: Stainless Steel 304/ 304L , SS 316/ 316L , Titanium, Hastelloy
  • Frame: Painted Carbon Steel, Stainless Steel 304
  • Gaskets: NBR, HNBR, CR-HT, EPDM , PTFE

Available Connection Types

  • ANSI or DIN Flanges
  • Butt weld pipe for refrigeration Applications
  • Studded ports with rubber or stainless-steel liners
  • Stainless steel ferrule for sanitary or pharmaceutical Applications

Code Compliance

Design and fabrication according to ASME with “U” stamp, PED ; Canadian Registration (CRN)

Max. Working Pressure 900 psig (62 Barg)

• Min. / Max. Working Temperature -50°F / 320°F (-50 C/160C)




• Heat Recovery Desuperheater

Oil Coolers

Under Floor Heaters

Ammonia-Carbon Dioxide Cascade Condensers

Applicable industries

  • Refrigeration
  • HVAC
  • Food and Beverage
  • Petrochemical and Process
  • Heat Pump

Other Options

  • Galvanized or Stainless Steel Drip pan for refrigeration applications
  • Protective Shroud for refrigeration and Hazardous fluid applications

Kara Consulting acts as the representative for Iso-therm Inc in four European countries; Netherlands, Belgium, France and Sweden.

(1) Publications relating to the plate and frame heat exchangers by Dr. Zahid Ayub:

Evaporation Heat Transfer and Pressure Drop of Ammonia in a Mixed Configuration Chevron Plate Heat Exchanger

M.S. Khan, T.S. Khan, Ming-C Chyu, Z.H. Ayub, 2014,

“Recent Developments in Plate Exchangers – Ammonia/Carbon Dioxide Cascade Condensers”

Journal of Heat Transfer Engineering,-Vol. 34, Nos. 5-6, pp. 401-408. International Journal of Refrigeration, Vol. 41, pp. 92-102.
Zahid Ayub, Sultan M. Khan, Amir Jokar, Tariq S. Khan and Neil Hayes, 2013,

Experimental Investigation of Evaporation Heat Transfer and Pressure Drop of Ammonia in a 30° Chevron Plate Heat Exchanger”

International Journal of Refrigeration, Vol. 35, No. 6, pp.1757-1765.
Zahid Ayub, Sultan M. Khan 2012


Study of carbon dioxide condensation in chevron plate exchangers; pressure drop analysis”

International Journal of Heat and Mass Transfer, Vol. 55, pp. 2916-2925.
N. Hayes, Amir Jokar, Dr. Zahid Ayub 2012


“Experimental Investigation of Evaporation Heat Transfer and Pressure Drop of Ammonia in a 60° Chevron Plate Heat Exchanger”

International Journal of Refrigeration, Vol. 35, No. 1, pp. 336-348.
T.S. Khan, M.S. Khan, Ming-C Chyu, Z.H. Ayub, 2012

Experimental Investigation of Single Phase Convective Heat Transfer Coefficient in a Corrugated Plate Heat Exchanger for Multiple Plate Configurations”

Applied Thermal Engineering, Vol.30, pp. 1058-1065.
T.S. Khan, M.S. Khan, Ming-C Chyu, Z.H. Ayub, 2010

Review of Heat Transfer and Pressure Drop Correlations for Evaporation of Fluid Flow in Plate Heat Exchangers (RP-1352)”

International Journal of Heating, Ventilating, Air Conditioning and Refrigerating Research, Vol. 15, No.2, pp. 169-188.
T. S. Khan, M. S. Khan, M-C. Chyu, Z. Ayub, and J. Chattha, 2009,

“Plate Heat Exchanger Literature Survey and New Heat Transfer and Pressure Drop Correlations for Refrigerant Evaporators”

Heat Transfer Engineering, Vol. 24, No. 5, pp. 3-16.
Ayub, Z. H., 2003,

(2) Patents related to Plate and Frame Heat Exchangers by Dr. Zahid Ayub

Distributer for Plate Heat Exchangers

Zahid H. Ayub, Arlington, TX (US) 2001.

Plate Evaporative Condenser and Cooler.

Zahid Ayub, Arlington, TX (US) Peng Peng, Shanghai (CN) 2014

Distributor for Evaporative condenser header or cooler header.

Zahid Ayub, Arlington, TX (US) Peng Peng, Shanghai (CN) 2014

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