STC,
The Dresser coupling and the Victaulic flexible coupling are not alike. The Dresser coupling would clamp on to plain pipe, while the Victaulic flexible coupling works within the grooved pipe limits. The Victaulic style 77 flexible coupling might be close to the Dresser coupling within small displacement limits. The Victaulic style W155 expansion joint with its multiple sections would be an order of magnitude more flexible, more like a hose.
If you have a anchor support on piping side close to the Victaulic coupling, then the loads on the pump suction will be negligible. The anchor support would take the pressure thrust plus piping loads, and the Victaulic coupling would allow small vertical + lateral + rotational movements between the anchor and the pump suction connection displacements.
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R Yee