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Thermocirculator and Recirculating Heater / Chillers


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Thermocirculator and Recirculating Heater / Chillers

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E3500 Thermocirculator

The E3500 Thermocirculator is a low cost, portable water circulating system for supplying a constant temperature supply for closed and open loop applications at near ambient to +60°C.


  • Precise control of heating
  • Compact
  • Robust and reliable
  • No running water to waste
  • Ideal for use with the E3100 Critical Point Dryer

The E3500 is suitable for open and closed loop applications and has all controls and liquid connections on the front panel. The temperature controller shows not only the "set" temperature (between ambient and +65°C), but also the actual liquid temperature. The fluid is circulated by a glandless magnetic pump, through an aluminum reservoir.

A cooling coil is mounted in the liquid reservoir. This coil can be directly connected to the main water supply and is primarily used when temperature control near to ambient is required. The electronic control system features a zero voltage switching unit which minimizes mains electrical interference, enabling the E3500 to be used and sited with other sensitive electronic instruments.

Using the E3500 with critical point dryers

The E3500 will give controlled heating of E3100 Critical Point Dryer. It is connected directly to the inlet and outlet of the E3100 water jacket. The temperature of the circulating fluid is pre-set,typically set to 37°C (just above the critical temperature of carbon dioxide).

Barley Leaf
Trichomes and stomatal pores on the epidermal surface of a barley (Hordeum vulgare) leaf. Some very fine wax crystallites are also just visible on the surface of the leaf.
Stomatal Pore on Xerophyte Leaf
Surface Critical point dried epidermis of a xerophyte (cactus), demonstrating raised stomatal pores.
Mature Spruce Wood
Critical point dried block of mature spruce wood block, demonstrating transverse, tangential and radial views of tracheids and vessels.


Working temperature range Ambient to +65°C
Heating rating 500W
Reservoir capacity 2.2L / 3.5 Pints
Pump type Glandless magnetic drive
Pump motor Shaded pole
Pump flow 270L/h (zero head) / 60 Gal/hr (zero head)
Pump pressure 0.25 kg / cm2 / 3.5 psi
Max pump head (unrestricted) 2.5 m / 7.5 ft
Size (unpacked) 330 x 280 x 150 mm / 13 x 11 x 6"
Weight 8 kg / 17.6 lbs
Electrical 220-240V/50Hz, 115V/60Hz
Temperature range -20°C to +70°C

Ordering Information

91095 E3500 Thermocirculator each POR Quote

E4800 Recirculating Heater/Chillers

Recommended for open and closed loop applications, offering simplicity, reliability and quiet operation. The range includes the E4860, 4870, 4880 and 4890.


  • Precise temperature control
  • Quiet, efficient operation
  • Proven reliability
  • Low maintenance
  • Environmentally friendly - avoids running water to waste

Some typical applications

  • Vacuum coating equipment
  • Critical point dryers including the E3100
  • Electron microscopes
  • Chromatography equipment
  • Electrophoresis baths
  • Environmental chambers
  • Crystal growth apparatus
  • Fermentation equipment
  • Interferometers
  • Photographic baths
  • X-ray equipment
  • Polarimeters, refractometers
    ...and many others

Temperature control

Many instruments measuring physical properties depend on accurate control of temperature and in some processes optimum temperature is essential. With the E4800 series, over-cooling (which affects efficiency) is prevented and the water temperature can be accurately controlled over the range -10 to +60°C.

A commonly misunderstood feature of refrigerated systems is in applications where the control temperature is other than at or near room temperature. When the instruments are to be operated at controlled temperatures below ambient, the extraction deteriorates significantly and, as a guide, the compounded change is 4% per degree Celsius. In practice, the refrigerant gas pressure has to be adjusted to optimize the performance at any particular temperature. However, the E4800 series incorporate automatic adjustment valves in the systems.

The E4800 series are "closed loop" and efficiencies are dramatically improved compared with open bath models. They are simple to set up and to operate, and essentially maintenance free.

Choosing the correct heater/chiller

In order to optimize performance from a heater/chiller system, the correct specification must be selected for a particular application. To cool or heat any instrument or system it is important to obtain the following information from the manufacturer:

  • Heat load to be dissipated to water, for an electron microscope: diffusion pump heater, lenses, etc
  • Flow rate and size of tubing
  • Minimum pressure

With this information, consult the Specifications below and select the appropriate heater/chiller. The basic heat load calculation formula is as follows:

Flow rate x weight of fluid x specific heat x D T = Heat Extraction.


Heat Extraction Rates (in Watts) - 20°C - 10°C 0°C +10°C + 20°C
E4860 75W 105W 180W 300W 420W
E4870 125W 250W 500W 900W 1.2kW
E4880 200W 425W 700W 1.6kW 2.2kW
E4890 350W 600W 1.2kW 2kW 3kW
4.5kW Recirculator 700W 1kW 2kW 3kW 4.5kW
6kW Recirculator 800W 1.3kW 2.6kW 4.5kW 6kW

Model E4860 E4870 E4880 E4890
Extraction rate at 20°C 400W 1.4kW 2.2kW 3kW
Temperature range -20°C to +70°C -20°C to +70°C -20°C to +70°C -20°C to +70°C
Refrigeration (HP) 1/5 1/2 3/4 1
Heater rating 1kW 1.5/2.0kW 2.5kW 2.5kW
Max pump flow 450L/h
Tank capacity 1.2L 1.7L 2.3L 3.0L
Max pump pressure psi/bar 12/60psi
Height 37cm 45cm 50cm 50cm
Width 32cm 38cm 45cm 45cm
Depth 46cm 61cm 62cm 62cm
Weight 40kg 62kg 70kg 82kg
Water connections 16mm hose or 1/8 BSP 16mm hose or 1/8 BSP 16mm hose or 1/8 BSP 16mm hose or 1/8 BSP
Temperature sensor R.T. Probe R.T. Probe R.T. Probe R.T. Probe

Optional Attachments

  • High pressure pump for E4860 and E4870 (standard in E4880 and E4890)
  • Water failure alarm
  • Over and under temperature cut out
    NOTE: Larger capacity heater/chillers (6kW and 12kW) are available on request - please contact us for further information
  • Custom-made heater/chiller units
E4860 (91098) 1/5 HP Recirculating Heater/Chiller each POR Quote
E4870 (91099) 1/2 HP Recirculating Heater/Chiller each POR Quote
E4880 (91090) 3/4 HP Recirculating Heater/Chiller each POR Quote
E4890 (91095) 1 HP Recirculating Heater/Chiller each POR Quote

Glow Discharge System

recirculating heater chiller