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4LPPT70EN - 5/2023
Using the pump in explosive conditions
Special safety precautions must be followed when the pumps
are used in explosive conditions. The compatibility of the
pump for use in conditions classified as Ex as defined by the
ATEX standard is indicated on the pump’s type plate.
Special attention must be paid to the following precautions:
• preventive maintenance measures (changing the hose
and lubricating the bearings)
• electrical earthing
• temperature of the pumped medium (heat is conducted
into the pump structures)
Other matters to be taken into consideration:
• The LPP-T pump lubricant may react with oxidising
substances, resulting in a risk of fire or explosion.
• The condition of the pump bearings and the sufficiency
of the lubricant must be checked at least every three
months (more often if the conditions so require).
• The pump frame must be earthed in case of static electric
discharge.
• The pump and the motor must be kept clean in order to
prevent excessive heat production. At normal operating
temperatures, the heat generated by the pump rotation
will not exceed 60 °C (140 °F). The surface temperature
of the pump may, however, exceed 60° C (140 °F) if the
temperature of the pumped medium is higher. When the
unit is used in compliance with the ATEX standard, the
maximum temperature of the medium is 70 °C (158 °F).
2.2 General description
Principle of operation
The pump’s operation is based on the peristaltic effect: The
cylindrical rotor, fitted with a bearing, compresses the hose
during the 360-degree working cycle. The rotor is installed on
a crankshaft that enables the eccentric movement; as the rotor
rotates, it pushes the pumped medium forward in the hose.
After the rotor, the hose returns to its original shape, thus
forming a vacuum within. The vacuum then refills with
medium from the suction side. The hose compression
is adjusted to prevent backflow through the point of
compression.
Mechanical structure
Figure 1. Main components of LPP-T pumps
1. Body
2. Drive unit
3. Crankshaft
4. Rotor assembly
5. Front cover
6. Hose