MAGNET VALVES (Electro-Soupapes)                                                     

1. Very ancient model 
(Extracted from an authentic Merklin Pipe Organ)
2. More recent: Kimber-Allen valves 3. Very recent Peterson Valves
4. MERKLIN valve : note the cotton for isolating the wire, and the paper around the magnet !

The recent models, (picture 3) are much more compact.
Electro soupape Merklin
Industrial magnet
Ancien électro-soupape à isolement coton...Vertical magnetIndustrial magnetIndustrial magnet
convenient  for pipe organs (2cmx2cm)
During a long time, Magnet valves had the shape represented in picture 1 or 4
Wires were isolated with cotton, very dangerous towards fire risks. Support was on the opposite side of the pallet, taking much more room. Some French "Organ Experts" are demanding mandatory to refurbish such magnets with cotton isolation ! Crazy !
(After official classification of them).