Johnson Pump SPX Flow CombiLineBloc Instruction Manual page 19

CombiLineBloc
CLB/EN (1901) 6.6
'Submersible multistage water pump' (MSS) means a multistage (i > 1) rotodynamic
water pump with a nominal outer diameter of 4" (10,16 cm) or 6" (15,24 cm) designed to
be operated in a borehole at nominal speed of 2900 rpm, at operating temperatures
within a range of 0°C and 90°C;
This Regulation shall not apply to:
1 water pumps designed specifically for pumping clean water at temperatures below -
10°C or above +120°C;
2 water pumps designed only for fire-fighting applications;
3 displacement water pumps;
4 self-priming water pumps.
• Enforcement:
In order to enforce this there will be a Minimum Efficiency Index (M.E.I.) criteria set for
the above list of pumps.
The MEI is a dimensionless figure that is derived from a complex calculation based on
the efficiencies at BEP (Best Efficiency Point), 75% BEP & 110% BEP, and the specific
speed. The range is used so that manufacturers do not take an easy option of providing
good efficiency at one point i.e. BEP.
The value ranges from 0 to 1,0 with the lower value being less efficient, this provides the
basis of eliminating the less efficient pumps starting with 0,10 in 2013 (the lowest 10%)
and 0,40 (the lowest 40%) in 2015.
The MEI value of 0,70 is classed benchmark for the most efficient pumps in the market at
the time of developing the directive.
The milestones for the MEI values are as follows;
1 1st January 2013 all pumps shall have a minimum MEI value of 0,10;
2 1st January 2015 all pumps shall have a minimum MEI value of 0,40.
The most important point of this is that unless the pumps comply then they
will not be allowed to have a CE marking.
• Part Load Performance
It is common practice that pumps spend much of their time working away from their rated
duty, and efficiency can fall off rapidly below the 50% duty point, any scheme should take
account of this real life performance. However, manufacturers need a pump efficiency
classification scheme that makes it impossible to design pumps with a steep fall off in
efficiency either side of the BEP point in order to claim a higher efficiency than would be
typical of real life operation.
• 'House of Efficiency'
The decision scheme 'House of Efficiency' takes into account design and application
purposes as well as the pump minimum efficiency dependence on flow. The minimum
acceptable efficiency is therefore different for each pump type. The pass-or-fail scheme
is based on two criteria A and B.
General 17