Switching device for switching electrical and/or thermal loads using magnetizable liquid

Wear-free, encapsulated switching of electrical and thermal loads, realized by moving a magnetizable liquid (ferrofluid) that positions a conductive liquid to make or break contact

• Wear-resistant and durable: no moving solid contacts, reduced contact wear.
• Inherent explosion protection: encapsulation of potential switching arcs within the fluid chamber.
• Lower complexity for thermal switching: contact-based heat conduction without conventional pumps in suitable applications.
• Energy-efficient control: optional use of (electro-)permanent magnets for holding functions with minimal power consumption.
• Scalable and layout-flexible: U-, O- or 8-shaped channel geometries for optimizing travel distance and controllability.

• Electrical switches/relays/load switches in harsh environments requiring arc encapsulation and a high number of switching cycles.
• Thermal switches/contact coolers for intermittent thermal loads in power electronics and sensors.
• Space and aviation systems where pump-free, robust fluid and switching functions are advantageous (relation to PAPELL/ferrofluid research).
• ATEX-related applications where encapsulation of switching processes is relevant for safety.

Ferrofluids can be precisely moved using magnetic fields and have been investigated, among other things, in the space context for pump- and mechanics-free fluid systems (e.g. PAPELL at the University of Stuttgart). These properties make ferrofluids ideal for reliable actuator and switching tasks without conventional, wear-prone mechanics.

Conventional relays and contactors are subject to mechanical wear and contact erosion, and at high loads and in the presence of arcing can complicate safety requirements (explosion protection); thermal loads often require complex pumping systems.

The switching device combines a fluid reservoir, a magnetizable fluid (ferrofluid), an electrically or thermally conductive liquid (e.g. liquid metal such as Galinstan), a system of electromagnets/permanent magnets, and a controller. Magnetic fields move the ferrofluid and position the conductive liquid to open/close the contacts.

• Patent-protected technology
• Support/consulting for the commercial implementation of the technology by the inventors
• Additional know-how

• Licensees/buyers for the patent family and/or
• Industrial partners for a product development project

Journal publication on thermal switches: 

https://link.springer.com/article/10.1007/s12567-024-00579-3

Journal publication on the FARGO experiment, including results for both types of switches: 

https://link.springer.com/article/10.1007/s12567-024-00539-x