General Description; Shaft Sealing; Mechanical Seal - Speck-Pumpen PY-2271 Serie Betriebsanleitung

3.2 General description

PY-2271/2/3
Pumps of the PY-2271/2/3 series are multi-stage, horizontal
centrifugal pumps in bracket version.
Two mechanical seals are used to seal the shaft.
The impellers are designed as peripheral impellers and fixed to
the motor shaft by means of threaded pins. The pump shaft is
supported by lifetime-lubricated rolling bearings.
The bracket is centred on the bearing shield of the motor and
fastened with screws. The drive is connected to the pump by
means of a claw coupling.
QY-1042 and QY-2052 series
Pumps of the QY series are multi-stage, horizontal centrifugal
pumps in close coupled version.
A mechanical seal is used to seal the shaft in the discharge
casing.
The impellers are designed as peripheral impellers. They are
floating on the extended motor shaft.
The discharge casing is centred directly on the bearing shield of
the motor and fastened with screws. The extended motor shaft is
additionally supported by a plain bearing in the suction casing.
Media to be pumped
Peripheral pumps are used for delivery of pure, aqueous liquids
which do not contain abrasive or fibrous particles.
Type Self-priming
PY-2271/2/3
QY
Tab. 7 Priming behaviour
Fig. 3 Multi-stage peripheral pumps:
PY-2271 at the back, QY-2052 at the front
05/2011
Not
self-priming
X
X
1096.0841 | PY-2271/2/3, QY-1042, QY-2052 Series
3.3 Design and functional principle
1 Impeller
2 Casing
3 Casing channel
4 Interrupter
Fig. 4 Mode of operation of a peripheral pump
The impeller (1) of a peripheral pump is designed as disc and
has radial blades at the outer diameter, which are milled into the
front and back side of the circumference.
On both sides of the impeller blades, channels are circularly
arranged inside the casing (3), through which the medium flows.
These circular channels (3) are interrupted between the casing
inlet and outlet (4) to prevent an overflow from the discharge to
the suction side.
The hydraulic power is transmitted by momentum exchange
between the impeller and the casing channel. Thus, relatively
high pressures can be generated with small geometries.

3.4 Shaft sealing

3.4.1

Mechanical seal


Mechanical seals may slightly leak for functional reasons.
The pumps are equipped with the following mechanical seal
types:
• Single seal, unbalanced, dependent on the direction of
rotation with conical spring
Operating Instructions
9