DEMAGNETISERS / FIXTURES

The demagnetising fixture is the mechanical interface between the component to be demagnetised and the demagnetiser.  The fixture produces the specific magnetic field pattern that is required for that particular application.  Hirst Magnetic Instruments Ltd. have a wealth of experience in the design and manufacture of demagnetising fixtures.

The demagnetising process usually requires an alternating field, reducing in strength over time, to be applied to the components to be demagnetised.  The material and size of the components will determine the strength of field required and the time base of the decay.  For most applications of small parts (less than 10mm wall thickness) a time base of a few seconds is required for the field to reduce to zero.

Demagnetising fixtures usually consists of a simple coil arrangement where the part to be demagnetised is placed inside the coil.  The fixture may have a round or rectangular aperture and may be in a vertical or horizontal orientation to allow easy loading of the containers.   If required, Hirst can design and build suitable handling systems to interface with customer's production methods.

T.V. screen de-magnetising fixture.

Dependant upon the size and weight of the components or containers, the fixture may be supplied as a floor standing unit often with a roller conveyor to allow easy operator handling.
Demagnetising fixtures are designed to interface with the Hirst range of Capacitive Discharge machines, with dedicated power supplies or mains frequency driven supplies.

Dependant upon the frequency of operation and energy used, the fixture may require external cooling to prevent overheating of the coil.  This can be achieved using compressed air, water or oil circulating through the fixture.  Hirst can supply complete cooling systems to compliment our fixtures as a complete turnkey solution.
Custom fixtures may also contain embedded search coils to be connected to a Hirst Integrating Fluxmeter as part of a quality control or magnet calibration system.

Our fixtures are usually supplied with the windings of the coils fully encapsulated in epoxy resin.  This provides a good mechanical support for the windings and provides operator safety by insulating the windings, which can see voltages of up to 3,000 volts.

Hirst Magnetic Instruments Ltd. can also manufacture coils to suit a customer's particular application or to interface with 3rd party magnetiser.