Magnetic Field Interference 
Products and Services

Without external magnetic shielding, much of today's sophisticated electronic gear would be larger, less efficient and in some magnetic environments, unlikely to function correctly. As components are made more sensitive and packaging more dense, susceptibility to electromagnetic interaction increases dramatically even in the best engineered layouts. 

Electromagnetic interference can originate from various sources. These could include permanent magnets or electromagnets, coil components such as transformers, solenoids and reactors, AC or DC motors and generators, and cables carrying large DC or AC current at power frequencies. In many cases, even the earth's normal magnetic field can affect proper functioning. 

Ambient Field Strength Surveys

RFI Industries will carry out field surveys to establish ambient field strengths. This is normally essential to calculate the shielding thickness required to avoid saturation. Field surveys or investigations can also help in discovering the cause of distortion on VDU screens or "that mysterious interference" to a computer system.

Inserts 

Honeycomb inserts are provided for ventilation or the connection of air-conditioning ducts. Special quench pipe penetration interfaces are installed for the venting of helium. RFI filters are installed to provide additional services for lighting, power outlets, signal circuits or CCTV as may be required.

Architectural Treatment

Most conventional architectural treatments are compatible with our modular enclosures. Suspended ceiling systems utilising aluminium grids and plain or acoustic panels enhance the interior. Walls may also be treated with acoustic panels, wallpaper or paint in a wide range of colours.

Special effect lighting, wall or ceiling mounted, complements interior decor whilst floors may be finished in vinyl or carpet tiles.

Clear View Window

RFI Industries' clear view window provides a clear sharp view of the patient. The window, fully glazed on both sides, incorporates a stainless steel mesh which eliminates moire effects.

Design Installation Testing 

RFI Industries offers a complete service to customers requiring consultation and design for M.R.I. facilities. In addition, our experienced teams travel world wide to meet shielding enclosure installation and testing requirements.

RFI Industries has designed the S900 System to provide versatility and reliability which will encompass a complete range of installation requirements to suit the majority of MRI Suppliers.

Our engineers are always pleased to discuss any requisite with supplier and architect so do not hesitate to contact them with your enquiries.

ELF Surveys 

A survey of magnetic fields or extra low frequency fields measures the strength of magnetic fields in an area to more clearly define the source and strengths of the interference, and to determine parameters to provide a solution where necessary.

Magnetic VDU Shields

There are many possible solutions to magnetic interference problems. Basically, either the device sensitive to field or the field source may be shielded. In typical monitor shielding situations, the source may be strong and occupy an extensive area, making source shielding difficult to design and very expensive. Relocation of the sensitive equipment to an area free of interfering fields may also be possible. For an easier solution, consider a shielded monitor enclosure.

A high permeability shield placed around a VDU is very effective against magnetic fields which emanate from power cables and power distribution boards. The shield prevents irritating "shimmer" or "waver" occurring on the screen.

High Permeability Foils

Many magnetic shielding problems can be solved with a pair of scissors and a sheet of magnetic foil. The foil is hand trimmed to the required outline and fitted around the structure to be shielded. Measurements then tell whether refinements are needed. Satisfactory ductile foil material, ranging from 0.002 to 0.01 in thick, is available in various permeability ranges.

Shielding of Bus Bars and Power Plants

It is necessary in some cases to provide shielding of bus bars or high current carrying conductors. These conductors produce high magnetic fields which will cause interference to adjacent electrical or electronic equipment e.g. V.D.U.'s, Television sets or Medical Electronic Devices. RFI Industries can design and supply shielding ducts or shadow shielding in plant rooms using high permeability steel or mu-metal materials.

Cable Duct Shielding

Cable duct or cable trays can be shielded to reduce the interference from magnetic fields. Various designs have been developed to suit particular applications.

Building or Room Shielding

High permeability steel is used for applications where ceiling, wall or floor shielding is required, such as in substations or where a large number of VDU's are affected.

Modular Magnetic Room Shield

For applications where a sensitive instrument such as an electron microscope requires protection from magnetic fields, a modular shielded room is available. The modular room is easy to erect on site and it provides excellent attenuation at various frequencies.

Mu-metal and Co-netic Materials

Mu-metal and Co-netic materials are available for specific applications where high levels of attenuation are required.

Engineer's Kit

An engineer's kit or lab kit is available which includes an AC magnetic probe and several pieces of Co-netic foils, Netic foils and braided sleeving. This kit assists the field engineer to develop a solution to a magnetic field problem against 50 Hz magnetic field interference.