5
The maximum pressure the pump may be subjected to is 1.5 times the head value developed with the outlet closed.
The vapour pressure value of the liquid to be pumped must exceed (by at least 1m w.c) to the difference between the absolute
total head (suction side pressure added to the positive suction head, or subtracted by the suction lift) and the pressure drops
in the suction side piping (including the inlet NPSHr drops shown on the specific tables).
In case of double mechanical seal, the value of the pressure in the seal chamber must be less than 1/3 of the operating
pressure value of the pump.
In case of double mechanical seal, the flushing liquid must be clean and must not lead to violent chemical reactions on contact
with the liquid being pumped.
The pump does not include any non return valve nor any liquid flow control or motor stop device.
4
OPERATING PRINCIPLE
HYDRAULICALLY alike to all centrifugal pumps, it is equipped with a vane-type impeller rotating within a fixed housing. It has a
tangential outlet and, by creating a depression in the centre, it allows the liquid to flow from the central suction side. Then,
flowing through the impeller's blades, the fluid acquires energy and is conveyed towards the outlet.
-MECHANICALLY the impeller is driven directly by the shaft The axiality of the pump-motor assembly is guaranteed by the self-
centring coupling system jointing the pump shaft and the motor shaft; All the mechanical loads, of a reduced nature in this
type of pump, are borne by the motor bearings.
-THE MECHANICAL SEAL, placed at the point where the shaft enters the pump body to drive the impeller, is made up of two
main section: a fixed section inserted in the pump body and a rotating section integral with the shaft. The tight contact
between these two parts guarantees a seal against leakage whether the pump is rotating or not. The rubbing action that
occurs between these two parts when the pump is operating generates heat by friction; this heat is absorbed by the liquid
being pumped in the case of single mechanical seal and by the cooling liquid (generally water) in the case of double seal
(trim the inlet pressure between 0.3 and 1 bar - flow approx. 0,1
0,3 l/minute). The presence of the thin layer of liquid
between the sealing surfaces, as well as its cooling action, is indispensable for the life of the seal.
5
MOTOR
Electrical connections
The electrical connection to the motor terminal determines the direction of rotation of the motor and can be verified by looking at
the cooling fan at the rear of the motor ( for the Argal pump this has to rotate clockwise looking at the front end).
With single phase motors the direction of rotation may be reversed by changing the position of the connection plates:
With three-phase motors the direction of rotation may be changed by swapping any two of the three conductors independently
of the type of connection to the windings:
The windings of three-phase motors ( e.g. with (a) 230-400 V; (b) 400-600 V) require a delta-connection for lower voltage ( 230
volts for a ; 400 volts for b).
They require a star-connection for higher voltage (400 volts for a; 690 volts for b).
N
L
N
L
T
S
R
W
V
U
Z
Y
X
S
T
R
W
V
U
Z
Y
X
T
S
R
W
V
U
Z
Y
X
T
S
R
W
V
U
Z
Y
X
Summary of Contents for ZMR 02.30
Page 2: ...2 1 DISASSEMBLING SEQUENCE ...
Page 16: ...16 ...
Page 17: ...17 ...
Page 18: ...18 ...
Page 19: ...19 ...
