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MCHZ
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
MCHZ/EN (0912) 4.2
Liquids
In general the MCHZ pumps are suitable for pumping clean liquids, such as:
• spring water, cold and hot water.
• various cooling liquids.
• caustic soda.
• petrol, kerosene, petroleum.
These liquids must not affect the materials used. For the materials used see the
appropriate parts list in chapter 9.
We advise against using the pump for an application which differs from that
for which the pump was originally supplied, without discussing this with your
supplier first! Using a pump in a system or under system conditions (liquid,
system pressure, temperature, etc.) for which it has not been designed can
create danger for the user!
Construction
Pump section
The pump section is assembled from an inlet and outlet casing and a number of sections
or stage casings with cast vanes. The inlet and outlet casings are fitted with a cast
suction and pressure flange. The support for the inlet and outlet casings are in a vertical
centre line with the suction and the pressure pipes.
The inlet and outlet casings are fitted with connections for pressure gauge, balance pipe,
possible barrier liquid and drain.
By using guide blades the radial forces on the rotor can be disregarded over the entire
capacity curve.
The stage casings are fitted with exchangeable wear rings. To prevent turbulence and for
the benefit of the required NPSH values, there is a suction cover with 2 anti-rotation
partitions located in front of the first impeller.
Self-priming section
The self-priming section contains a built-in vacuum pump which operates according to
the liquid ring principle. Air or gas which is sucked in is discharged immediately via the
pressure pipe, provided there is no back-pressure.
Impellers
All types of MCHZ pumps, are fitted with closed impellers, designed with 2 sealing
edges and balance holes. As a result of this the axial forces on the rotor are reduced to a
minimum. The remaining forces are taken up by an axially mounted bearing. The impellers
are held on the shaft by 2 stainless steel external circlips.
Bearing construction
• All MCHZ pumps are designed with 2 grease-lubricated deep-groove ball bearings.
• For the types MCHZ 20a and 20b a double-row angular contact bearing is used on
the pressure side.
• Pumps with heavy bearing constructions - used for MCHZ 14a and 14b - are fitted
with 2 single-row angular contact bearings on the pressure side.
• MCHZ(S) 12,5, 14a/b (with standard bearings) and 20a/b are provided with 2RS1-
bearings.
• The MCHZ 16 and MCHZS 16 are fitted with grease nipples so that these bearings
can be greased periodically.
• The bearing housings are fitted with 2 holes so that the stuffing box is easy to access.
General
15
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