BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to thermal management for thermal cycling systems, such as heat pumps and heat sink assemblies.

2. Description of the Prior Art

Conventional heat pumps typically include a control unit with an electronics circuit board with electrical components that generate significant heat during thermal cycling of the heat pump. Such system generally utilize independent active cooling features, typically electronics fans, for cooling of the electronics circuit board. In addition, since the electronics can act as heat sources, the circuit board is often located remotely and attached to the heat pump through wires. This approach further increases the size, complexity and demands of the overall system. Thus, there exists a need to further simplify the thermal management of such heat pump systems as well as reduce the complexity and minimize the occupied size of such thermal cycling systems and associated control systems.

BRIEF SUMMARY

In one aspect, the present invention provides a thermal management solution capable of dissipating the heat from an electronics board assembly controlling a heat pump while simultaneously controlling the temperature of a heat sink of the heat pump.

In some embodiments, the present invention includes one or more air tubes or conduits that pull air from the back of the instrument by creating a negative pressure. In some embodiments, the invention includes at least two air tubes or conduits, one on each side of the electronic board assembly. The air then travels through the one or more air tubes and flows into an electronics board assembly thereby providing cooling of the components inside the assembly. The above-described approach simultaneously pulls air from the front of the instrument through the heat sink of the heat pump of the thermocycler as well. The air tubes or conduits can take various cross-sectional shapes (e.g. round, oval, square, rectangular, triangular, a regular polygon, an irregular polygon, or any suitable shape, or combination of shapes). While typically, the air tubes or conduits are straight, it is appreciated they can be curved or can extend along a varied path. The air tubes or conduits can be made out of any suitable material, including but not limited to: polymers (e.g. plastic), metals (e.g. aluminum), ceramic, or composites. In some embodiments, the one or more tubes or conduits can be added to an existing assembly. In other embodiments, the one or more tubes or conduits can be integrated within the assembly, for example integrated within the chassis of the instrument. In some embodiments, the one or more tubes of conduits can be formed of a thermally conductive material (e.g. metal, such as aluminum) so as to provide heat sinking of some other parts which are thermally coupled with the one or more tubes or conduits.

In some embodiments, the electronics board assembly is defined by at least two electronic printed circuit boards (PCBs), one of which includes high power electrical components that act as heat sources during thermal cycling operation. The air flowing between the PCBs dissipates heat from these heat sources. The main advantage of such a system is that one or more fans, typically two fans located at the back of the instrument, can be used to create laminar flow through the heat sink while the air tubes draws in air between the PCBs that dissipates heat from the electronics onboard. This approach is advantageous since no independent cooling system is required to dissipate heat from the electronic components.

Due to the relatively high impedance of the heat sink, a proper airflow ratio should be maintained between the heat sink and the electronics board assembly. In addition, due to direct contact between the heat pump and thermal board assembly, some of the heat generated by high electrical current in the heat pumps is transferred to the thermal board assembly which is ultimately dissipated to outside. Thus, the thermal solution described-above can effectively reduce the heat generated by the heat pump and the control circuit board assembly concurrently. In another aspect, this approach can also minimize non-uniformity of the sample block of the heat pump by reduction of the heat generated in the high current circuitry of the PCBs at the top surface of the heat pump. The conformable nature of this approach permits its use even in applications where space is limited. Another benefit of this approach is that it allows the one or more the cooling fans to be positioned elsewhere (for example, at the back, underneath or at the sides of the instrument) which leaves space in the front of the instrument available for other auxiliary components, such as LCD, cables, etc.

In some embodiments, the thermal management assembly includes one or more partition plates between the electronics board assembly and the heat sink in order to separate the airflow coming from the heat sink and the airflow drawn through the circuit board assembly. This approach advantageously provides isolation between temperature-elevated air coming from the heat sink and the electronic components. Due to the high efficiency of such systems, hermetic seals are typically not required between different components of the thermal management assembly.

Another object of the present invention is the provision of maintaining stability or minimizing temperature fluctuation of the thermal board assembly in order to minimize failure of the board even at the temperature-elevated environment.

Another technical advantage of the system is that the thermal boards can be directly coupled with the heat pump, thereby reducing or eliminating any cable routing that might obstruct airflow. This approach also allows building of an assembly that includes a heat pump, thermal boards, fans, and air tubes or conduits as a module. Providing this assembly as a module is convenient for both manufacturing and service as the module can be removed for repair or replaced.

In one aspect, the thermal management assembly described herein provides thermal management without the need of any hood or enclosure. The assembly can embodied by at least two PCBs that are sandwiched together and directly interface with the heat pump of a thermocycling system.

In another aspect, the components of a thermal management system are not cooled sequentially, as often seen in certain conventional systems, but rather the heat pump and the electronics board assembly are cooled concurrently or simultaneously.

In yet another aspect, the thermal management device provides thermal management without requiring any moving of the sample. For example, the assembly provides thermal management without requiring any application of centrifugal force, as found in certain conventional systems. There is no reason to move the sample during thermal cycling since the heat pump and electronics board assembly can be cooled simultaneously or concurrently.

In some embodiments, the cooling system is relatively planar, which contrasts with cooling systems designed for test tubes, and which allows for reduced size as compared to certain conventional systems having additional external cooling components attached thereto.

Various aspects of the present invention can be further understood by referring to the following figures.

