POWER November 2010 - 22

4. Uses standard welding tools. Because the outer surface
behaves like mild steel, Ultra 600 can be cut and welded using standard
procedures in the field and can accept the standard end options
of flanges, weld rings, and couplings. Courtesy: Ultra Tech
5. Air suspension ride. Recent removal and replacement of a
reactor recirculating pump was facilitated by a custom-designed air
cushion system. Only two technicians were required to guide the
50,000-pound system through the plant. Courtesy: AeroGo
Ultra Tech estimates that Ultra 600 pipe will last two to four
times as long as mild steel in high-wear applications.
-Contributed by Ultra Tech Pipe.
shearing action on the pipe wall. In more extreme cases, these
effects can result in pipe leaks or failure, or significant maintenance
costs and downtime for pipe replacement. Mild steel
pipe is simply not tough enough to stand up to the abuse for
more than a year or two.
Most abrasion-resistant pipe options operate on the premise
that when two objects meet, the harder object wins. To
deal with this phenomenon, products are available in a variety
of hardnesses, measured on the Brinell Scale, from A-R steel
(200 BHN) through iron cast pipe (up to 800 BHN).
Unfortunately, any product that is very hard throughout
the wall thickness is also extremely brittle. Excessive brittleness
is unacceptable, as piping systems are constantly flexing
and moving as a result of pressure surges and spikes and due
to mechanical and physical contact at a plant.
However, one type of pipe promises to deliver the best of
both worlds: an induction-hardened pipe with an abrasionresistant
inner surface that tapers to a strong, yet ductile
outer surface. Ultra 600, manufactured by Port Washington,
Wisc.-based Ultra Tech begins with a steel pipe manufactured
to a proprietary chemistry, followed by induction heating and
water-quenching of the inner surface to create a single-wall
pipe (Figure 3).
At 600 BHN, the inner surface of this induction-hardened
pipe can withstand most common abrasives. The pipe tapers
to a 250 BHN outer surface that is ductile enough to endure
normal handling during shipment, installation, and maintenance.
With this proprietary process, pipe can be manufactured
in various diameters up to 40 inches and in varying
lengths and wall thicknesses. The pipe can be cut and welded
like mild steel and accepts standard end options of flanges,
weld rings, and couplings (Figure 4).
The company can also produce the Ultra 600 pipe in long
radius bends to further reduce wear and eliminate the frequent
replacement, repair, and associated expense accepted
as the norm at bends and elbows in high-wear applications.
22
Air Casters Speed Equipment Moves
When it comes to moving megaton items like feedwater heaters
or recirculating pumps, conventional moving tools such as
wheel rollers, cranes, hoists, and come-alongs may be virtually
useless. In some cases, moving large components is dangerous
in a space-constrained location surrounded by delicate
process control equipment.
Feedwater heater and recirculating pump removal and replacement
are two situations in which nuclear plant operators
have used AeroGo for moving equipment weighing up to
5,000 tons on an invisible cushion of air (Figure 5).
Recently, a reactor recirculating pump was replaced at a
nuclear plant located on the eastern seaboard. The pump was
first removed vertically from a well in the reactor chamber,
turned on its side, set on rails, and then pulled onto a cart.
The whole load then had to be backed up and pivoted to align
with an egress hall, a passageway lined with hydraulic control
systems for the nuclear reactor core rods. There was no room
for mistakes. Even paint scrapes were considered part of the
radiation hazard potential.
AeroGo created a drivable cart mounted on air casters that
allowed the 50,000-pound pump to transit through twists and
turns of the passageway to an outside area where it could be
loaded onto a truck. Estimated clearance was an optimistic 1
to 2 inches. Only two drivers, each controlling a compressed
air-powered traction device located at opposite ends, moved
the cart. The cart's mating fixtures were engineered to flex in
order to mate precisely with the giant pump, aided by Acme
screws at each corner to allow tiny, incremental adjustments
for a perfect fit.
Of course, when recirculating pumps are removed, there
must be a replacement. The company moved the new pump in
with equal ease using the same air caster transport system-
but this time with a crew from a second shift that had not
received prior training in using the system. AeroGo technicians
trained them on the spot in less than 20 minutes, and
the move was flawless. ■
www.powermag.com
-Contributed by AeroGo.
POWER| November 2010
http://www.powermag.com
POWER November 2010

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