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Need advice on which model? Dry Block Selection Guide

The Gemini range of Dry Blocks have high capacity allowing a large number of probes to be calibrated together. They are also suitable to accept large diameter probes with the block volume of a nominal 64 x 160mm. Whilst the large block takes longer to heat and cool than the Jupiter it can calibrate thermocouples, resistance thermometers, thermostats and sensors that are too large for the smaller blocks.

These award winning calibrators are easy to use and are available in three versions – the Basic, the Site and the ADVANCED. The Basic has a digital display of set and nominal temperature, the Site additionally includes an inbuilt independent temperature indicator for a reference probe. The ADVANCED controller has inputs for reference and test thermometers with a further range of sophisticated features including automatic temperature cycling, secure data logging and full colour high resolution display. All models include I-Cal Easy LOG software and the ADVANCED models additionally include software to manage logged data and configure the unit.

Available with a fixed block with four 8mm and four 19.5mm pockets or the LRI version which has a removable block. With the LRI model, blocks can be drilled to custom configurations.

Isotech is a world leader in temperature calibration, providing many nations with their Primary Standards and operates a full scale UKAS accredited calibration laboratory. We can offer a range of calibration options to meet your requirements.

These models meet the calibration capacity requirements of EURAMET calibration Guide 13 “EA Guidelines on the Calibration of Temperature Block Calibrators”


ParameterModel Gemini 4857
Temperature Range35°C to 550°C50°C to 700°C
Absolute Stability over 30 mins±0.01°C @ 100°C ±0.015°C @ 300°C ±0.03°C @ 550°C
Display Resolution0.01°C over whole range
Input Channel Accuracy: ThermocoupleE, J, K, N: ±0.2°C @ 660°C R: ±0.6°C S: ±0.7°C @ 660°C T: ±0.2°C @ 150°C
CJC Accuracy±0.35°C
Input Channel Accuracy: RTD±0.05°C ±0.005% RDG
Absolute Stability over 30 mins±0.02°C @ 50°C ±0.03°C @ 250°C ±0.04°C @ 550°C
Display Resolution0.01°C from 30.00 to 99.99°C then 0.1°C: 0.01°C Over PC Interface
COMMON Specifications
Cools from 550°C to 275°Cin 35 mins (LRI: 132 mins)
Cools from 550°C to 60°Cin 345 mins (LRI: 420 mins)
Heats from 30°C to 550°C35 mins (LRI: 60 mins)
Heats from 50°C to 700°Cin 110 mins (LRI: 120 mins)
Best PerformanceSee GraphSee Graph
Calibration Volume65mm diameter, 160mm deep
Indicator Units°C, °F, K
Voltage115Vac or 230Vac 50/60Hz
Power600 Watts (LRI: 1000 Watts)
Dimensions384H (including handle) x 212W x 312D mm




Gemini 4857

High Capacity Blocks to 700°C

The Gemini range of Dry Blocks have high capacity allowing a large number of probes to be calibrated together.

  • Calibrate Large Diameter Probes
  • High Capacity Blocks 64 x 160mm
  • Calibrate Whole Measurement Loop

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Or call +44 01704 543830

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