Gorman-Rupp has introduced a new range of self cleaning sumps designed
by Yves Givron to deliver multiple efficiencies in function, energy use and
A fourth generation wet well, the self cleaning sump (SCS) is designed
for use with self-priming Gorman-Rupp sewage pumps, and keeps the fluid in the
system moving to maximise self-cleaning.
Gorman-Rupp self cleaning sumps are designed to eliminate blockages
caused by the build-up of rags and stringy materials, sediment build-up in the
sump, fat and grease build-up, and air entrainment as well as reduce energy
consumption, gases and odours, need for ‘well washing’ and blockages in the
pump, thereby lowering maintenance costs and civil costs.
The design concept
Gorman-Rupp self cleaning sumps are designed to keep the liquid moving
for as long as possible; pump at a liquid level that produces the best cleaning
effect; and keep non-pumping times short. The sumps are reliable, safe, easy to
access, and easy to maintain.
The complete system consists of a Gorman-Rupp self priming packaged pump
station with VFD controls; a short sloping collector pipe in HDPE (to replace
the conventional concrete wet well); and a modified maintenance/man hole (with
sloping bottom to direct flow into the SCS).
The operating procedure is designed to clean solids out with every cycle. The
pump starts at the ‘on level’ at full speed to maximise re-priming lift
(minimising re-prime time), and slows down at the ‘regulation level’ where the
velocity is at its highest to transport solid matter, including silt, fats,
grease and stringy material. The VFD controls maintain this level (by speeding
the pump up or slowing it down) for about 5 minutes.
If the pre-set minimum speed is able to lower the level, or if the
pre-set regulation level time limit has been reached, the pump will speed back
up to maximum, pumping down to the ‘off level’ to empty the SCS. This faster
speed is designed to maximise self cleaning and remove as much silt, fat and
stringy materials as possible.
If there is a longer than acceptable delay between the next pumping
cycle, the pump will cut-in prior to reaching the normal ‘on level’ so that
solids do not get a chance to settle out.
This mode of operation is designed to keep the solids moving, minimising
the chance of silt build-up or stringy materials ‘balling’ or ‘matting’ together.
It not only minimises blockages but also reduces solids build-up, therefore
eliminating the need for expensive sucker truck call-outs. Chances of air
entrainment are close to zero as the suction line entry for the pumps is at the
farthest point from the influent line.
Fat build-up is also eliminated because the system keeps the fat, grease
and floatables moving so that they cannot build up. This eliminates the need
for well washing equipment and also reduces the odours and gases created by
these stagnating solids. Energy consumption is also reduced because the longest
part of the pump cycle is at the ‘regulation level’, and the flow rate and head
are lower than at the design flow.
All self cleaning sumps (SCS) need to be paired with above ground self
priming pumps. Gorman-Rupp’s Ultra V Series or Super T Series sewage pumps are recommended
for the application. Self priming pump stations are easy to access, making
access to valves, gauges, motors and the pumps much easier than having to open
wet well lids and valve vault lids.
Gorman-Rupp sewage pumps, available from Hydro Innovations, can be
fitted with the new ‘Eradicator’ solids management system to handle the
toughest ragging applications. The Eradicator system features an aggressive
self-cleaning wear-plate incorporating a number of notches and grooves, as well
as a patent-pending lacerating tooth that helps break up stringy materials and
pass them through the pump without impacting performance or interrupting
The Eradicator system also comes with a smaller and much lighter
inspection cover-plate to make it easier for operators to inspect pump
internals and remove blockages if a blanket or similar has worked its way into
The SCS system used in conjunction with a Gorman-Rupp packaged pump
station can improve many of the issues confronting sewage pump station designers
and asset owners. This new approach can reduce blockages, odours, air
entrainment, energy costs, maintenance costs and construction costs while
greatly improving operator safety.
Please visit the Hydro Innovations website at www.hydroinnovations.com.au or
call 02 9898 1800.