Installation
236 Series Twin-Screw Pump -
Installation, Operation & Maintenance Manual
41
Flange position criteria
Acceptable position
Axial
The flange gasket thi0.25mm (0.010in), +1mm (0.040in)
Parallel
Align the flange to be parallel within 0.3° 1mm per 200mm (0.063 per
12in).
Concentric
Studs are centered in the holes or the flange bolts can be inserted and
moved by hand.
Fastening
WARNING:
Risk of serious personal injury or property damage. Fasteners such as bolts and nuts are
critical to the safe and reliable operation of the product. Ensure appropriate use of fasteners
during installation or reassembly of the unit.
The fasteners must be the correct size and material. Any fasteners found to be corroded,
galled, stripped or otherwise damaged must be replaced. Ensure that all fasteners are
properly tightened and that there are no missing fasteners.
Suction-piping checklist
Suction-piping checks
Check
Explanation/comment
Checked
Check that any pipe elbows do not
have sharp bends.
Use long radius elbows to change direction
wherever possible.
Check that the suction piping is one or
two sizes larger than the suction inlet
of the pump.
Install an eccentric reducer between
the pump inlet and the suction piping.
(For vertical suctions a concentric
reducer can be used).
The suction piping should never have a smaller
diameter than the suction inlet of the pump. This
minimizes the pipework friction losses leading up to
the pump.
Check that the eccentric reducer at the
suction flange of the pump has the
following properties:
• Sloping side down
• Horizontal side at the top
Not applicable for pumps with a vertical suction
arrangement
Check
Explanation/comment
Checked
It is recommended that a
commissioning (temporary) suction
strainer be used.
After commissioning it is
recommended an operating
(permanent) suction strainer be used.
Check that the strainer has at least five
times the area of the suction piping.
Some applications with very high
viscosities may not be able to
successfully utilize a suction strainer
due to the losses these introduce. If in
doubt consult with the system
designer.
Suction strainers help to prevent debris from
entering the pump
Recommended commissioning (temporary) strainer
mesh size:
• Viscosity<=86cSt (450 SSU) use 60 mesh
• Viscosity>86cSt (450 SSU) use 40 mesh
• Viscosity>216cSt (1000 SSU) use 20 mesh
Continuously monitor the pressure drop across the
suction strainer.
Limit the pressure drop across the strainer to the
lesser of 0.7bar (10 psi), or the vapor pressure of
the pumped fluid. System flushing is complete
when the strainer pressure drop stabilizes, and
periodic inspection of the strainer confirms that any
accumulation of debris has stopped. At this point
