In Modular PAN Design mostly a 2mm thick GI sheet is turned into a PAN by 90 degree bending its all the four edges two times .The diagonal joint is welded by MIG/TIG welding to ensure radiographic quality of welding. The bends range from 25 to 60 mm, generally 40 mm. Oblong slots are made at the side bend for joining these PANS/Panels to the other ones
These PANS are bolded together with nuts and bolts with a metallic railroad wire mesh gasket thus making straight wall/corners/roof/floor etc
The wire mesh /gasket used is made by different type wires uniquely made for EMI/EMC shielded enclosures. These are tin (3%) plated copper(40%) coated iron (57%) wire in just about 0.11 mm diameter or mantel wire etc.
Advantages of PAN type total steel structure (TSS) over traditional wood core structure (WCS) type Modular Structures
There are reasons why TSS has gained lot of interest these days so that user asks it by name
Different thermal expansion or contraction of wood w.r.t Gl threatens the Shielding Effectiveness of WCS rooms due to differential stresses thus loosening the joints and need to be maintained regularly which is very cumbersome process.
TSS is not affected by water and moisture, which play havoc with WCS system.
WCS room has many leak points (screws both surfaces of hat and flats and any joints areas of inter section). TSS has only one point of possible leakage (missing bolt) and still there is an RF gasket.
TSS is lighter in weight with fewer parts than wood core designs and very easy to assemble
TSS offers years of maintenance free, high RF attenuation.
TSS is very desirable in geographic regions with seismic problems. A WCS room can break apart.
TSS has higher fire-retardancy.
TSS can be easily disassembled and reassembled without degradation of Shielding Effectiveness. In WCS the disassembled panels will not seal properly after reassembling because the wood is compressed where it was clamped.
Other Aspects /Requirements of Shielded Structure:
In addition to the shielded walls there are many important design aspects of these structures like
Shielded Doors ranging from single leaf to big sliding door to accommodate even EMI/EMC testing of air craft.
Air vents generally designed with cut-off ware guide characteristics of honey- comb structure.
Signal Filters: Such as
Power line filters both for single/three phase power supplies of different current ratings, frequencies including DC filters and filters for
Telephone line filters.
Optical waveguide feed through
Isolation transformers, etc
Single Point earthing
Earthing Pits: Shielded structure, isolation transformer are to be connected to earth pits. Instead of conventional type of earthing pits using copper /GI plate with charcoal /salt etc, these days pipe-in-pipe type electrolytic type maintenance free earthing creating artificial good earth around the earthing pipe are being done.
ACE, Mhow, India chamber made by us using TSS on turnkey basis had following SE requirements.