September 2013 Tube Products International
31
products & developments
Resistive internal
coatings for pipework
Problems of corrosion, erosion, fouling
and wear are common in pipework,
pumps, valves and other hollow process
vessels. Conventional metal coatings
are often ineffective and difficult to
apply consistently, but a new process
overcomes these problems.
InnerArmor, available from Wallwork
Group company Tecvac, uses plasma
enhanced chemical vapour deposition
(PECVD) to apply even, pinhole-free,
thin films of highly resistive diamond like
carbon (DLC), titanium carbide or other
resilient coatings.
Applications for the new
process include pipework and
plant in oil and gas exploration
and production, downstream
petrochemical processing, in
chemical plants, water industries
and other process plants.
Providing an effective barrier on
mild steel and other common
metals, InnerArmor eliminates
the need to use costly exotic
metals or alloys. Typical coatings
vary from 30 to 80 microns.
They can be optimised for hardness,
wear and erosion resistance
or to tolerate acids, salts,
hydrogen sulphide or fluids
with abrasive solids such as
sand and grit.
Thin films of different
materials may be deposited
in multiple layers to optimise
adhesion to the substrate
and resistance to chemicals
or harsh solids.
Multi-layer coatings are
stronger and subject to
less stress than single
layer coatings of the same
thickness.
The InnerArmor process uses
the pipe or process vessel
to be coated as the reaction
cell.
Insulated sleeves link this to the
positively charged anodes via which the
source gas, at a prescribed temperature
and pressure, is pumped through the
void. Ionisation of the gas results in
even deposition of the coating on the
inner surface of the vessel. In addition to
protecting the vessel from attrition by the
pipe contents, the process can prevent
pipe contents being contaminated by
failing pipe material, so preserving
product quality and value.
Tecvac operates the InnerArmor process
under licence from Sub-One Technology
of California, with whom they share
worldwide applications experience.
Pipe lengths of up to 3m can be coated
effectively, as well as pump and piston
chambers and other complex shapes.
PECVD is environmentally benign,
producing no volatile solvents or
harmful waste streams, nor requiring
high energy input.
Wallwork Heat Treatment Ltd
– UK
Pipework, pumps, valves and other hollow process
vessels benefit from surface coatings applied to internal
surfaces to reduce corrosion, erosion, fouling and wear
Internal pipe lengths of up to 3m
can be coated using PECVD
Valves from China
Wenzhou Hightech Valve Co has been
active in the field of valve manufacturing
for more than 20 years.
The company has manufactured more
than 80 models of valve in over 800
specifications, such as gate valves,
globe valves, check valves, ball valves,
butterfly valves, strainers and plug
valves, with designs according to API,
ANSI, DIN, JIS, BS, GOST and GB
standards.
The products’ nominal diameters range
from DN15 to DN1200 (
1
/
2
" to 48"),
with nominal pressure of Class 150 to
Class 2500 (PN10-PN420); operating
temperatures range from -196°C to
around 680°C.
Hightech Valve Co, Ltd
–
China
