Substd. di:chloro-phenyl-amino imidazoline prepn

The electrical immersion heater comprises tubular core units each having an elongate tubular core member (1) which may be provided with fluid through flow apertures. Each core includes a saw tooth profile strip (3a) which locates the wound wire, and is secured by stud fasteners (2) to core (1). Wire retaining slots (3) are provided at the ends of the strips (3a). A polymer insulated electrical resistance heating wire (5) is wound helically around the core (1) in a single layer. The core windings comprise a single length of resistance wire and the end feeds (4 and 6) connect with a shrouded supply cable (7). Side members (8 and 9) are of channel form with a central plateau (10) also forming a channel (10a) carrying spigots (11) each with opposed longitudinal slots (12) and an annular rib (13) arranged such that the spigots may snap-engage with the ends of respective cores to be secured. A number of the modular units described may be coupled together. Simpler adjustment of power rating. Avoids over-heating. @(8pp Dwg.No.1/3)@