Annular groove graphite heat exchangers

Graphite heat exchanger

Annular groove graphite heat exchangers (interchangers) are especially adapted to the heating or cooling of ultra-corrosive liquid chemicals. This specific design allows for heat recovery between two ultra-corrosive fluids. Annular grooves are machined into impervious graphite discs to form the process and service channels. Heat is transferred by conduction through the graphite left between the process and the service channels. Annular groove graphite heat exchangers consist of a stack of graphite discs that are fused together.


3D Renderings

3D animations


  • Impervious graphite: GAB GPX1, GPX1T or GPX2
  • Shell, pressure plates and flanges: carbon steel or stainless steel
  • Tie rods, nuts, bolts, washers, springs: stainless steel


  • Totally modular design: number of discs, size of discs and number of passes can be adjusted
  • Impervious graphite discs with annular groove (spiral)
  • Maximum disc diameter: 900 mm
  • Three different groove widths possible
  • Parallel groove arrangement from 1 to 21 grooves
  • Wavy groove design for increased turbulence (optional)
  • Graphite nozzles on product and utility sides
  • Thermal expansion compensation ensured by tie rods and helical springs
  • Carbon-fiber reinforcement (optional)

Key Features:

  • Design pressure: -1 barg (full vacuum) to +10 barg (145 psig)
  • Design temperature: -60 to +200°C (-76 to 392°F)
  • Heat transfer area: 0.3 to 55 m2 (3 ft2 to 592 ft2)
  • Design: according to European PED, ASME code, Chinese Pressure Vessel code and other national pressure vessel codes on request

Key Benefits:

  • Outstanding corrosion resistance on one side (RA series) or on both sides (WA series)
  • Superior heat transfer performance thanks to adjustable cross sections on both sides that guaranty a high level of turbulence
  • Gasket-free design (fused discs)
  • Resin-free surfaces (impregnation before machining) prevents release of black particles
  • Self-cleaning design prevents fouling and clogging
  • High operational safety
  • Highly reliable equipment therefore low cost of ownership and low maintenance cost
  • Compact and robust design
  • Short lead time
  • Long lifetime

Optional features:

  • Sight glass

Main applications:

  • Heat recovery
  • Heating or cooling of ultra-corrosive chemicals
  • Heat transfer between two ultra-corrosive chemicals
  • Best suited for single purpose units

Technical documentation:



PIRN12-EN-US Graphite Annular Groove Heat Exchanger - RA and WA Series (SI and US units)
PIRN12-EN-US Graphite Annular Groove Heat Exchanger - RA-WA Series.pdf (534.52 KB)


TI021-EN GMP compliant Annular Groove Condensers
TI021-EN GMP compliant Annular Groove Condensers.pdf (234.69 KB)

TI041-EN Graphite Condensers - Annular Groove vs. Block Design

WS1041-EN Annular Groove Heat Exchanger - Vertical Installation - Extended Endplate

WS1042-EN Annular Groove Heat Exchanger - Vertical Installation - Support Collar Mounting

WS1048-EN Annular Groove Heat Exchanger - Horizontal Installation

WS1550-Form-EN Questionnaire for Graphite Heat Exchangers - detailed

WS1551-EN Questionnaire for Graphite Heat Exchangers

WS1052-EN Annular Groove Heat Exchanger - Vertical Installation - Base Plate

Annular groove heat exchangers

Annular groove heat exchangers transfer heat from one liquid medium to another liquid medium without direct contact between fluids. For material properties, cost and efficiency reasons, annular groove heat exchangers are not manufactured out of any material other than impervious graphite.

The thermal performance of annular groove heat exchangers can vary significantly. It is therefore essential to select the type and size of heat exchanger that are the most adapted to the specific application and industrial process. There are a number of considerations including flow rate, pressure drop, risk of erosion, design pressure and temperature, material compatibility, fouling, and many more that should be taken in account.

GAB Neumann’s annular groove graphite heat exchangers – RA and WA series

GAB Neumann’s annular groove graphite heat exchangers are designed to cool down or heat up ultra-corrosive chemicals. Safety, reliability, and performance on the long-term are our primary considerations when we size, design and manufacture annular groove heat exchangers.

Our extended and highly customizable heat exchangers portfolio enables us to provide particularly adapted solutions to liquid - liquid heat interchange. All our annular groove graphite heat exchangers’ designs are totally modular to best fit with individual process specifications. The number and size of discs, the number and width of channels as well as the number of passes both on process and service sides can be adapted to best meet the velocities, pressure drops, and heat transfer requirements.

They can be fitted with optional features such as sight glasses if required.

All our impervious graphite annular groove heat exchangers are machined after phenolic resin impregnation thus guarantying a heat transfer surface which is totally free of resin and there ensuring the highest possible heat transfer rate.

Industrial processes

  • Crop protection
  • Fumed silica
  • Silicones
  • Titanium dioxide
  • Fine chemicals
  • Active pharmaceutical ingredients
  • Fire retardants
  • Flavors and fragrances
  • Vitamins
  • Polycarbonate
  • Coagulants
  • Treatment, purification and concentration of spent acids
  • Sulfuric acid dilution
  • and many more…

GAB Neumann GmbH

Alemannenstrasse 29

79689 Maulburg


Tel: +49 (7622) 6751 0

Fax: +49 (7622) 6751 20

GAB Neumann GmbH | Alemannenstrasse 29 | D-79689 Maulburg | Phone +49 (7622) 6751 0 | Fax +49 (7622) 6751 20 | E-Mail |