The document describes FOILEX TDS pumps, which are positive displacement pumps used for oil spill recovery and off-loading tanks. The TDS pump has a unique "Twin Disc Screw" design that provides 70% higher capacity than traditional screw pumps. Key features include a large displacement and exposed pump screw area for handling viscous oils, small outer dimensions, replaceable sealing discs, and exchangeable large discharge connections to reduce pressure drop.

1. FOILEX TDS TECHNOLOGY
INTRODUCTION
FOILEX TDS Pumps are mainly used for oil spill recovery onboard FOILEX’ own
Weir Type Skimmers as well as many other manufacturers’ skimmers, and as
separate transfer pump units for off-loading of for example tanks and sunken vessels.
FOILEX TDS 200 Sea Skimmer FOILEX TDS 150 Off-loading Pump
The revolutionary TDS “Twin Disc Screw” Pump design, with improved capabilities
for high viscous oil pumping, has up to 70% higher capacity than any other
traditional Archimedian Screw Pump design when compared at equivalent rpm and
screw diameter.
The "Twin Disc Screw" Pump has two
circular Sealing Discs fitted to each side
of the pump screw creating its positive
displacement and required pressure
when pumping.
Each disc operate in an alternating
fashion and allows the pump screw
diameter to be fully utilised during 2 x
180° of each revolution, thereby
facilitating the large and unique
displacement of the TDS Pumps.
FOILEX Engineering AB www.foilex.com Phone: +46-31 222525

2. Page 2 of 5
1. FOILEX TDS PUMP FEATURES
1.1 LARGE DISPLACEMENT
Displacement and Pump Screw diameter are
the two important design parameters that gives
the Positive Displacement Index, PDI of a
Screw Pump. The PDI is independent of pump
size and pump speed.
Positive Displacement Index:
PDI = 7 x D / d3
D = Displacement
d = Screw diameter
The FOILEX TDS Design has a PDI = 1,7
which is 70% more compared to traditional
Archimedian screw pumps today.
The large displacement provides high output
capacity in low to medium viscosity oils
or......to operate efficient at low rpm in high
viscous oils with a minimum of emulsification.
The combination with large exposed pump
screw area and large discharge connection
provides unique capabilities for high viscous oil
pumping.
1.2 LARGE EXPOSED PUMP SCREW AREA
The 3 x 120° pump inlet sections in combination with
the long feeding screw provides a large exposed
rotating screw area.
The TDS Pump will therefore mechanically catch,
mix and cut debris contaminated high viscous oil and
feed it into the pump section independent of the
pump suction capability.
This feature is very importance especially when
pumping high viscous oil with low or non fluid
characteristics.
FOILEX Engineering AB www.foilex.com Phone: +46-31 222525

3. Page 3 of 5
1.3 SMALL OUTER DIMENSIONS
The unique TDS design provides very small
outer dimensions compared to its pump
screw diameter.
The TDS Pumps are therefore very useful as
off-loading pumps in emergency situations
where only narrow tank inlets are available.
Min. Manhole Diameter
• TDS 150: 300 mm / 12"
• TDS 200: 420 mm / 17"
• TDS 250: 550 mm / 22"
FOILEX TDS 150 Pump is the World’s First
Archemedian Screw Pump that fits into the oil
tankers standard 12" Butterworth hatch.
1.4 FULLY MACHINE MADE PUMP SCREW
All TDS Pump Screws are identically and
fully machine-made in its pressure build up
zone.
Each Sealing Disc thereby fits snugly and
provides a tight and safe seal.
To provide an abrasive resistant surface, the
Pump Screw is coated with a hardened
chemical nickel coating for minimum wear of
both Sealing Discs and Pump Screw.
FOILEX Engineering AB www.foilex.com Phone: +46-31 222525

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2. MORE FOILEX PUMP FEATURES
2.1 CUTTING KNIVES AT INLET AND OUTLET
The pump inlet is equipped with three cutting
tools and one circular cutting knife in
hardened stainless steel for efficient debris
handling.
The high torque motor is sufficient to cut all
type of debris such as wood, seaweed,
plastics, ropes, etc.
The larger TDS 200 and 250 Pumps are at its
outlet also equipped with four hardened
stainless steel cutting knives to prevent
clogging, etc. All cutting devices can easily be sharpened when worn.
2.2 REPLACEABLE SEALING DISCS
The replaceable Sealing Discs are available in Polyurethane or Nitril Rubber
depending on application.
• Polyurethane:
Extremely resistant to abrasive wear,
such as sandy oil, etc.
• Nitrile rubber:
Suitable for operations in
aggressive oils, high temperature
and steamy environments.
Split Pump Casing provides easy and direct
access for service and inspection of the
sealing discs.
No need to dismount the inlet weir or other
skimmer parts for inspection.
FOILEX Engineering AB www.foilex.com Phone: +46-31 222525

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2.3 EXCHANGEABLE DISCHARGE CONNECTIONS
To reduce pressure drop and pipe resistance
to a minimum, especially when pumping high
viscous oil, it is of great importance to keep
the discharge hose / pipe diameter as large
as possible.
Pipe resistance will drop significantly when
going from Ø 3" to Ø 8".
Outlet Diam. Vs Pressure Drop:
• Ø 3" : 100%
• Ø 4" : 32%
• Ø 6" : 6%
• Ø 8" : 2%
Foilex TDS Pumps have exchangeable Discharge Cones from ∅ 3” to ∅ 8”.
2.4 ANNULAR INJECTION FLANGES
For reduction of pressure drop and pipe
resistance all Foilex TDS Pumps can be
equipped with Annular Injection Flanges for
steam, water or other diluting liquids.
Annular Injection Flanges can reduce
pressure drop up to 90 % in certain
conditions.
However, the first step to reduce pressure
drop and pipe resistance to a minimum when
pumping high viscous oil is to keep
Discharge Connection and Hose diameter as
large as possible. (see feature above)
FOILEX Engineering AB www.foilex.com Phone: +46-31 222525