Richter MPB 25-25-115 - Manual (Page 10)

Series MPB, close-coupled design Page 10
9240-050-en Revision 05
TM 7345 Edition 10/2008
Do not tighten the foundation bolts uniformly and
firmly until the mortar has set.
Other possibilities of alignment are:
4-point-alignment
4-point-alignment with base plate.
As soon as additional installations are
mounted, the stability of the entire unit
installed without a foundation must be
checked.
5.3 Alignment of pump - motor
Special notes of the motor manufacturer are
to be observed.
Use supports in the direct vicinity of the bolts
foundation/base plate.
5.4 Piping
Before the pump is installed, both the suction and
supply lines as well as the discharge line are to be
cleaned.
Dirt or damage to the sealing surfaces is best avoided
if the flange covers remain on the flanges until just
before installation.
Use flange gaskets suitable for the medium.
The screw tightening torques in Section 1.1 are to be
observed for tightening the flange screws.
5.4.1 Nominal size
The operating design point of a centrifugal pump lies
at the intersection of the pump curve and the pipe
curve, see Fig. 2. The pump curve is provided by the
pump manufacturer. The pipe curve is determined
using diagrams or PC programs.
Fig. 2
Under no circumstances can the nominal size of the
piping be derived from the connected nominal size of
the pump.
The pipe nominal size can also be determined using
the flow rate as a rough guide.
) m ( A
) s / m ( Q
) s / m ( v
2
3
=
The velocity in the suction line should not exceed
2.0 m/s and 5.0 m/s in the discharge line.
When determining the suction line nominal size, the
NPSH value (net positive suction head) must also be
observed. The
NPSHR value required for the pump is
specified in the data sheet.
The NPSHR available in the plant
should be at least 0.5 m higher than
the NPSHR required for the pump.
Otherwise, this will lead to a drop in the delivery head,
cavitation or even failure of the pump.
5.4.2 Nozzle loads
The pump can be subjected to nozzle loads in
accordance with ISO 5199. See also
TIS 0541-02-
0006 .
Changes in the length of the piping caused by
temperature are to be allowed for by appropriate
measures, e.g. the installation of expansion joints.
5.4.3 Suction line
The suction lines must always be laid on a rising
gradient towards the pump. Otherwise, gas bubbles
may form which considerably reduce the suction line
cross section. Eccentric transition elements must be
installed between different pipe diameters.
Valves which disrupt the course of flow should not be
installed directly upstream of the pump.
Fig.3
A volume of liquid in the suction line permits self-
priming with a peripheral pump.
Application example for a liquid similar to water,
20°C, venting time approx. 5 minutes.