|Block heater and cooler (BHC) is designed for widely use in Chemical, Biochemical, Clinical and other General Labs for storage, heating, digesting, incubating, concentrating and other heating and cooling processes, and due to the incorporating three stages temperature programming, it is much useful in enzymatic and other chemical catalytic reaction.The BHC is using Peltier to fulfil the heating and cooling process. The BHC has the capacity to increase or decrease the block temperature to higher or lower than environmental temperature. In addition, the cooling capacity helps the BHC machine quickly ramp down the temperature to the lower temperature setting. This is greatly helping the temperature reaching equilibrium quickly.The BHC accommodates many different variety of blocks regardless the different block thickness, 25 mm, 35 mm, and 50 mm (for thicker blocks, it takes longer time to reach the equilibrium, or even very hard to reach the extreme temperature setting, such as 0 and 100 ˚C). The BHC is designed to be relatively independent on the environmental temperature. For example, if you set the temperature at 25 ˚C, it becomes heating process when you operate the machine in the cold room (environmental temperature < 25 ˚C), or cooling process when you operate the machine at environmental temperature > 25 ˚C. It is same case as whether the block temperature is higher or lower than the setting point, the BHC can always start the correct process and to reach the correct setting point.BHC differs from PCR and other heating/cooling machines in which the thermistor is located inside the sample blocks (or plates). Even the dry block has similar configuration as the BHC, the dry block can only use relatively identical block format (same block thickness) and use heating process only. Our unique control algorithm does not need any input from users, and can be operated in various cases: different block thickness, and different environmental status etc. BHC always can bring the block temperature to the closer points of the setting temperature point.Since the BHC can work more flexible than other heating/cooling machines, it sacrifices that the accuracy of the block temperature at setting points (it could be varied in the range of +/- 5 ˚C). We need a good calibration method to do quick correction to reach the accurate point. The calibration must be easily to operate, and avoid the frequent calibration for the users.In normal calibration method, the calibration step must be done before running the sample. It takes a long time and could be time consuming process. Most importantly, the normal calibration methods (regardless multi-points calibration or change the value thru a potantiostat) change the system thermo-table value. It will greatly affect the performance of the machine and need to do very often calibration.The new calibration in the BHC machine is totally different from present method. There is no special calibration step in the machine. The calibration can only be done in the equilibrium stage during run. In the equilibrium stage, users enter the correct value, and the machine will start to run again to reach the new equilibrium point. At this time, the timing will be paused if running the timer, and will be resumed after reaching the new equilibrium. In the same time, the correct value will be stored in the memory as individual point. The system thermo table remains unchanged. In the next run, the machine will look up the memory to find the calibration value first, if it could not find, it will look back to the system table. The memory can store more than 70 points, and when the memories full, the new data will push out the oldest data out of memory.
BHC has a warning light, and it will be turned on when the machine temperature reaching above 50 ˚C.
There are three major thickness of blocks:
- The 50 mm thickness type of blocks, usually used for large volume and incubation or storage purpose. The maximum and the minimum block temperature can only reach 80 ˚C and 10 ˚C.
- The 35 mm thickness type of blocks, usually used for medium volume (5 – 10 ml vials). It can reach the set temperature ranging from 0 – 100 ˚C. However, it could take longer time to reach the equilibrium point.
- The 25 mm thickness of type of blocks, usually used for smaller volume (up to 2 ml vials). It is designed to use in enzymatic, catalytic and other chemical reaction which required fast ramping rate reaction.