Flowserve Twin Screw Rotary - Manual (Page 6)

TWIN SCREW PUMPS. ORIGINAL USER INSTRUCTIONS. ENGLISH. 71569243 – 07/10
Page 3 of 53
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RELIEF VALVE PIPED BACK TO THE
SUCTION LINE REQUIRED
The Twin Screw Pumps are positive displacement
pumps and will build up considerable pressure if
discharge line is blocked.
DRAIN THE PUMP AND ISOLATE PIPEWORK
BEFORE DISMANTLING THE PUMP
The appropriate safety precautions should be taken
where the pumped liquids are hazardous.
FLUORO-ELASTOMERS (When fitted.)
When a pump has experienced temperatures over
250 ºC (482 ºF), partial decomposition of fluoro-
elastomers (eg Viton) will occur. In this condition
these are extremely dangerous and skin contact must
be avoided.
HANDLING COMPONENTS
Many precision parts have sharp corners and the
wearing of appropriate safety gloves and equipment is
required when handling these components. To lift
heavy pieces above 25 kg (55 lb) use a crane
appropriate for the mass and in accordance with
current local regulations.
GUARDS MUST NOT BE REMOVED WHILE
THE PUMP IS OPERATIONAL
THERMAL SHOCK
Rapid changes in the temperature of the liquid within
the pump can cause thermal shock, which can result
in damage or breakage of components and should be
avoided.
NEVER APPLY HEAT TO REMOVE ROTOR
Trapped lubricant or vapour could cause an explosion.
HOT (and cold) PARTS
If hot or freezing components or auxiliary heating
supplies can present a danger to operators and
persons entering the immediate area action must be
taken to avoid accidental contact. If complete
protection is not possible, the machine access must
be limited to maintenance staff only, with clear visual
warnings and indicators to those entering the
immediate area. Note: bearing housings must not be
insulated and drive motors and bearings may be hot.
If the temperature is greater than 68 °C (175 °F) or
below 5 °C (20 °F) in a restricted zone, or exceeds
local regulations, action as above shall be taken.
1.6.4 Products used in potentially explosive
atmospheres
Measures are required to:
• Avoid excess temperature
• Prevent build up of explosive mixtures
• Prevent the generation of sparks
• Prevent
leakages
• Maintain the pump to avoid hazard
The following instructions for pumps and pump units
when installed in potentially explosive atmospheres
must be followed to help ensure explosion protection.
Both electrical and non-electrical equipment must
meet the requirements of European Directive 94/9/EC.
1.6.4.1 Scope of compliance
Use equipment only in the zone for which it is
appropriate. Always check that the driver, drive
coupling assembly, seal and pump equipment are
suitably rated and/or certified for the classification of the
specific atmosphere in which they are to be installed.
Where Flowserve has supplied only the bare shaft
pump, the Ex rating applies only to the pump. The
party responsible for assembling the pump set shall
select the coupling, driver and any additional
equipment, with the necessary CE Certificate/
Declaration of Conformity establishing it is suitable for
the area in which it is to be installed.
The output from a variable frequency drive (VFD) can
cause additional heating effects in the motor and so,
for pumps sets with a VFD, the ATEX Certification for
the motor must state that it is covers the situation
where electrical supply is from the VFD. This
particular requirement still applies even if the VFD is
in a safe area.