While other constructions are permissible and would fall within the scope and spirit of the present invention, the pole piece 24 of the illustrated embodiment forms {HEAD ~ an integral part} of {TAIL ~ the valve assembly} 1 
While other constructions are permissible and would fall within the scope and spirit of the present invention , the pole piece 24 of the illustrated embodiment forms { HEAD ~ an integral part } of { TAIL ~ the valve assembly } 1
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH