21 PB0347:m-620atex-en-03
11 Tube life
A number of factors contribute to the life of the tubing:
Factors influencing tube life
Normal tube fatigue -dependent on tube size and material
Incorrect tube loading - see section 15 "Continuous tube loading" on page28 or section 14 "620REA
and 620RE4A LoadSure tube element loading" on page26.
Excess working pressure - see section 10 "Operating parameters" on page19
Chemical incompatibility - a table of tubing compatibility can be found on www.wmftg.com/chemical.
Immersion kitsare available from Watson-Marlow for testing.
For each application it is strongly recommended that tube life should be determined by trials, prior to
installation in a hazardous environment. If this is not possible, or if there isany doubt in terms of tube life
then the following hazards should be recognised before installing a pump in a potentially explosive
atmosphere:
Seesection 19 "Materials of construction" on page36 for information on materials of construction.
Chemical reaction between pumped fluid and pump materials the materials of construction are listed
at www.wmftg.com/chemical.
Pumped fluid can be ignited by surface temperature of rollers - all Watson-Marlow’s ATEXequipment
has been rated as T4. (Meaning that even under worst-case operating conditions the maximum
surface temperature willnot exceed 135C (275F)
In normal circumstances, rotor and tube life are maximised if the pumphead is run slowly, particularly
when pumping at high pressure. However, to maintain performance at pressures above 2 bar, avoid
running the pumphead below 50rpm. If low-flow, high-pressure operation is necessary, switching to a
smaller tube isrecommended.
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