Bowtie Impeller
Mike: I've been looking through my G.E. Parts Catalog listings. There is a small margin of error here because I'm looking at the dates of the Parts sheets, which may have dates that don't exactly coincide with manufacturing dates.
Looks like the last Black Impeller dishwasher was the SU60N - the parts sheet is dated April 1957.
The next model in sequence in the Part sheets, is the SU60P and SU60P1, which had the Bowtie Impeller - the parts sheet is dated January 1958.
The above are stationary dishwasher units.
The Portables (excluding the early Round models) of the Mobile Maid era begin in the parts sheets with Model SP40M1 - which used the Black Impeller - the parts sheet is dated April 1957. The model SP40N and SP45N are variations with the same April 1957 dates.
The Mobile Maid that I believe you are referring to, Model SP40P, is the first portable to have the Bowtie Impeller - parts sheet is dated January 1958. Various models follow - with dates as late as December 1962 - all of which have the Bowtie Impeller.
Then there are new models introduced with the Spray Arm - with dates beginning in July 1962. And the impeller, as we know it, was gone forever.
Summary - Bowtie began in 1958 and lasted through 1962.
Mike
