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Mechanical Technology — October 2015
⎪
Hydraulic and pneumatic systems
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H
ighpoint Vacuum was found-
ed by its current CEO, David
Gade in 2004, initially to
support the mining industry.
Visser explains: “We started out provid-
ing capital equipment rentals of vacuum
machines on skids and trailers to recover
fines on the mines. Once drilling opera-
tions are completed at a gold mine, for
example, the area is covered with gold-
bearing dust. The traditional method
of recovering these fines was to wash
it into a central area and pump it from
there. But gold is heavy, so it does not
always move with the surrounding dust
and this was a very inefficient process.
Using vacuum is far more efficient and,
since the product is valuable, more cost
effective,” he explains.
To overcome replacement component
supply shortages and long lead times,
Highpoint began to manufacture com-
ponents and units for its rental fleet,
including its own vacuum pumps. This
healthy business has now been split off
into Highpoint Rentals.
“Then we started to supply vacuum
trucks to industrial cleaning companies
such as Enviroserv and Bidvest. These
companies go into plants and refineries
to recover hazardous materials that need
to be collected, transported and disposed
of in the safest and most environmentally
responsible way. At Holfontein on the
road to Delmas, Enviroserv manages the
only toxic waste dump in the country,”
Visser continues. “Our vehicles are clean-
ing ash plants at the older power stations,
which contains sulphur that can cause
acid rain if it enters the atmosphere, so it
has to be collected and disposed of. We
are also active in the cement industry
with a truck designed for dry bulk such
as cement powder and lime.
“More recently, we have started to
look at the municipal waste and sewage
markets, with vehicles for unblocking
and cleaning sewage and stormwater
drains,” he adds.
The vehicle and equipment arm of
Highpoint Vacuum is now capable of
manufacturing four vehicles at a time
on a to-order basis, within a four-month
lead time from order to delivery – and
production capacity is now more than
20 vehicles per year.
“We make vehicles in three basic
categories: HPVR Liquid Ring vehicles for
hazardous industrial waste; HPVR PDP
trucks for dry bulk materials; and HPVR
Combi trucks, which combine jetting and
vacuum for line cleaning,” Visser tells
Founded only 10 years ago, Highpoint Vacuum is a Sasolburg-based original equipment manufacturer of
industrial and municipal vacuum trucks for mineral recovery, waste disposal and cleaning.
MechTech
visits the
manufacturing facilities and talks to engineering manager, Jean Visser, about the company’s designs, its vacuum
pumps and the sophisticated hydraulic systems used.
Shown here under test at the company’s Wonderfontein facilities near Sasolburg is the
‘backbone’ vehicle for industrial cleaning in South Africa, Highpoint Vacuum’s HPVR-1000
Liquid Ring.
South Africa’s mobile vacuum OEM
MechTech
, adding that several variants
and customisations of each of these are
available.
Liquid ring vacuum HPVRs
The ‘backbone’ vehicle for industrial
cleaning in South Africa is Highpoint
Vacuum’s HPVR-1000 Liquid Ring,
which has a 12,5 m
3
stainless steel
(316L) tank that is kept under vacuum
by a 1 200 cfm (2 038 m
3
/h) liquid ring
vacuum pump designed and manufac-
tured by Highpoint.
Explaining how a liquid ring pump
works, Visser says that an impeller is
rotated inside an eccentric barrel that
contains a quantity of liquid ‘sealant’.
When the pump starts, the impeller
slings the liquid sealant by centrifugal
force to the outside walls of the barrel,
forming a concentric ring of liquid around
the outside walls. The liquid seals off
the space between each impeller blade,
trapping air in each of the void spaces,
called impeller cells.
“Because the impeller is off-set from
the barrel walls, when the blades are
close to the walls, the cells are nearly
fully immersed in liquid and the pockets
of air are small. But when the impeller
tips are further away, the impeller cells