VP 741D

Heat Block Overview

V&P Scientific builds robust, low-profile, ambient to 200^oC Heat Blocks that enable heating and stirring in standard microplates, deep well microplates, or reaction blocks of glass tubes and sealed vials.  They are constructed out of a specially designed Eddy Current defeating aluminum designed to be used with our strong NdFeB Tumble Stirrers.  Although aluminum is not magnetic, when magnetic lines of flux pass through it, an eddy current of electricity is generated that heats the aluminum and causes the motor that is generating the magnetic field movement to work much harder.  That is why we invented the Eddy Current defeating design.  The low profile design also minimizes the distance from the samples to the magnetic field thus maximizing the stirring power of even viscous materials.

Each Heat Block comes with one or more SLAS Adaptor Bases made of Mica that are attached to the Heat Block’s underside. This base provides heat protection for surfaces below the Heat Block and facilitates its use in microplate-configured locations. The Mica is safety rated by UL laboratories as UL 94VO.  Another advantage of our design is that we have separated the control panel from the actual heating block. Thus, the Heat Block’s placement on the deck of a robotic workstation is seamless.

Our temperature controllers all use an RTD (Resistive Thermal Device) heat sensor.  RTD sensors are advantageous because they work in moving magnetic fields generated by V&P Tumble Stirrers while Thermocouples do not work in magnetic fields. This is important when heating and stirring simultaneously.

The VP 741 Series and VP 742 Series Heat Blocks have deep chambers and a lid that can be screwed into place to hold Cap Mats or other sealing materials in place while high temperatures are reached.  Heating and simultaneously stirring are very useful in redox chemical reactions.  Our deep chamber Heat Blocks all come with a U-shaped insert that allows easy removal of standard microplates or other short labware.

The VP 744 Series Heat Blocks are heated or cooled by recirculating hot or cold fluid in the heat exchange channels in the blocks.

The following graph contains data generated in a VP 741ABZ-R-MB Heat Block using a deep well 96 microplate with 2 ml of water in each well.   The RTD of the controller is embedded in the aluminum at the base of the Heat Block.  The Control temperature was set to 80° C and temperature readings were taken in microplate wells located at the middle (C6), side (A6), and corner (A12) positions and plotted against time.  As can be seen in the graph the temperature in the wells plateau at 4 to 6° below the set temperature of 80° C.   This difference between the set temperature and the well temperature needs to be determined and compensated for, in your system using your fluid, your volume, and your microplate or other vessels. This difference in set temperature and well temperature is due to the loss of heat transfer between the aluminum and the microplate and the fluid in the well.  Also note the best heat transfer occurs in the wells with the greatest contact with the aluminum of the Heat Block, and with time these approach the same temperature.  This is why we make Heat Block accessories that maximized the contact between the Heat Block and the microplate or vessel.