Thermal Platforms and Thermal Plates Information
Thermal platforms are used to heat and cool electronic devices through conduction. These platforms are alternatively known as hot plates, thermal plates, or hot/cold plates. Particular models use gases, such as liquid carbon or liquid nitrogen, to alter the temperature or keep it at a set point. Other models rely on closed-loop mechanical systems to eliminate the dependence on gases for operating purposes.
Solutions cooled or heated by thermal platforms ideally possess thermally conductive flat surfaces. Compared to environmental chambers that rely on thermal convection, the process of conditioning the device using platforms occurs substantially faster. Conduction allows for rapid temperature cycling, resulting in improved component throughput. The platforms occupy less space and offer enhanced energy efficiency compared to chambers due to their compact dimensions.
The systems operate in a variety of applications, including sample preparation, electronics, and biotech/pharmaceutical sectors. They perform prompt heating and cooling within the established temperature limits. The surface of the thermal plate consists of aluminum or similar materials that offer optimal temperature control. Certain compact models are ideal for benchtops at laboratories or production facilities and aim to facilitate uninterrupted access to the components undergoing conditioning.
Several thermal platform types exist to accommodate multiple uses. The two primary types include:
Cryogenic platforms: These platforms utilize gases such as liquid nitrogen or carbon dioxide to execute cooling and heating operations. They support swift temperature transitioning and require a lower initial investment. High-density arrays of electric resistance heaters are employed for heating purposes. In the absence of built-in compressors, heaters with high power consumption are an alternative option to achieve quick heating.
Closed-loop mechanically operated platforms: These units rely on closed-loop refrigeration systems for cooling. As a result, gases such as liquid nitrogen or liquid carbon dioxide are irrelevant to their operation. This reduces the costs involved in running the systems by eliminating expenses related to purchasing and handling cryogenic coolants. It also eliminates the need to deal with the build-up of dry ice and water condensation.
Mechanically cooled platforms are advantageous for applications where fast ramp rates are not essential and for longer cooling periods. Clean environments employ such systems due to the absence of coolant discharge.
Closed-loop mechanical refrigeration systems operate by re-circulating ozone-friendly refrigerants. Air-cooled condensers are used to eject heat as a byproduct of the system's operation. Alternatively, these systems integrate water-cooled condensers to manage heat release.
Thermal platforms operate as a single stage or as cascade systems. Single stage systems rapidly and efficiently cool and heat a platform within specified temperature thresholds. The rate of transition decreases significantly once the desired temperature reaches the limit. These systems feature one compressor and one type of refrigerant. The cooling process slows down when the temperature difference between the boiling point of the refrigerant and the platform falls below 10°C.
Cascade systems employ two compressors as well as two types of refrigerants. This allows the system to achieve a significantly lower operating temperature than with single stage systems. Some platforms feature embedded copper tubes as cooling channels in combination with AC cartridge heaters. This design provides superior accuracy in temperature uniformity in conjunction with minimization of thermal gradients at temperature. Thermal platform cooling channels are milled into the platform, eliminating issues related to heat exchange.
Thermal platform features include:
- Anodized surface (for added durability)
- Control software
- Programmable ramp and soak profiling
- Environmentally friendly refrigerants
- Programmable ramp to set point
- EIA 232 interface
- IEEE-488 GPIB interface
- Temperature sensors
- Stainless steel chassis
- Threaded holes in all four corners (for adapter plate mounting)
- Integrated temperature control
- Remote temperature controller
- Clamp set mounting
Thermal platforms are used in an array of applications including:
Selecting Thermal Platforms
Several factors including budget, application, capacity, and a multitude of features and device capabilities must be considered when selecting a thermal platform.
Cryogenic platforms feature lower up-front costs compared to mechanical refrigeration systems. However, their use of gases as refrigerants brings higher maintenance costs. The exhaust gas from the systems makes them unsuitable for conditions requiring a clean environment.
Mechanically operated platforms feature lower ongoing operating expenses and are more suitable for clean room operations. Clean rooms require virtual "vacuum" conditions, where the air is free from particles and contaminants known to harm specific devices during production. Products such as electronics and semiconductors require such environments.