Gorman-Rupp U4B Super U Series Self-Priming Pump

The Gorman-Rupp U4B is the 4 inch model of the Super U Series, which the manufacturer describes as the most efficient self-priming, solids-handling pump available, with efficiencies up to 73 percent. It trades some solids size for a unique volute casing that minimises friction loss and drag, giving 650 GPM at 195 ft with 0.81 inch solids passage.

Efficiency rather than brute solids size

The multi-vane open impeller is made of ductile iron and handles solids up to 1-1/4 inch on the series, while operation stays efficient across a broad range: loads left or right of the best efficiency point reduce efficiency by only a small percentage. The brochure compares 73 percent for the Super U against 63 percent for another self-primer and 54 percent for a vertical turbine pump, and shows an estimated five-year saving chart. These are manufacturer comparisons and should be treated as such. The U4B suits water reuse stations, process transfer and industrial or municipal duty where power cost matters and solids are modest.

Technical specification

Maintenance without breaking pipework

A patented external shimless adjustment allows impeller to wearplate clearance to be reset by hand without realigning belts or couplings; Gorman-Rupp says it doubles impeller and wearplate life. The removable coverplate with easy-grip handle and pusher bolt capability gives access to the interior, and the whole rotating assembly slides out after four bolts are removed from the back (the front on 6 inch models). Because there is no elongated shaft, routine service can be done in confined spaces. A pressure relief valve, seal and bearing oil monitors, optional casing heater and a suction check valve on selected models complete the design.

Drive and sizing

Super U pumps are supplied as basic units for flex-coupled or V-belt drive by an electric motor, and all can be coupled to a standard NEMA motor. V-belt drive allows speed selection to reach the required head and capacity without trimming the impeller. The series can also be part of a ReliaSource packaged system.

Duty point in other units (derived)

Unit conversions below are calculated from the printed maximum values and are not manufacturer statements.

Because power cost drives total life cycle cost for a continuously running pump, the efficiency of the U4B is its main selling point, and the brochure shows how its curve stays flat around the best efficiency point. V-belt drive allows the sheave ratio to be set so the pump runs at the speed needed for the head and capacity without trimming the impeller. Give the full operating range, not only one duty point, when selecting.

Options and support

The Super U brochure notes that the pump can be part of a ReliaSource packaged system, that heating of the casing and several belt and sheave options are available, and that performance curves, manuals, parts lists and outline drawings are supplied in PDF and CAD form through the manufacturer. A five-year warranty is stated on the Super U Series. For enquiries, give the required flow range, because the broad efficiency curve makes selection of belt ratio and motor size straightforward.

Frequently asked questions

How efficient is the Super U Series?

The manufacturer states efficiencies up to 73 percent.

What are the U4B limits?

650 GPM (41 lps), 195 ft (59 m) and 0.81 in (21 mm) solids.

Is it interchangeable with Super T?

Suction and discharge dimensions are interchangeable with Super T Series models.

Can clearances be adjusted without shims?

Yes, via the patented external shimless adjustment.

What material is the casing?

Cast iron.

Documents and quotation

Brochure: Super U Series (AV-05573). More in Pumps. Seven Star LLC is an independent supplier in Muscat; send duty point and motor data to quote.