VARISCO GS Series Operating And Maintenance Manual Download

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Pompa ad ingranaggi - Serie GS, GK

Gear pump - GS, GK Series

In our pumps the direction of rotation is clearly shown by an arrow marking the right direc-
tion.

The  pump  operating  temperature  in  normal  working  conditions  is  about  80  °C.  In  special
pump versions, working temperatures of 180 °C and more may be achieved. To protect per-
sonnel from dangers due to the temperatures reached during the operation of the machine,
in the event of accidental contact (burn), the User must reduce the external pump tempera-
ture  by  means  of  insulation  plates, coatings, screens,  barriers,  etc.  As  limit  reference  tem-
perature  for  the  contact  surface  it  is  advisable  to  take  55  °C.  Below  this  value,  for  hot
smooth surfaces in bare metal, there is no burn threshold. For a detailed knowledge of this
problem in relation to different particular cases, the User can read the standard UNI EN ISO
13732-1,  where  burn  thresholds  are  specified for several  types  of surface  according to the
“surface temperature - contact time” parameters.

Liquids to be pumped must not contain abrasive or solid suspension as this will greatly re-
duce the pump life. At this purpose we recommend the installation of a properly sized filter
on the suction line if solids may be present.

When pumps are installed in parallel, the suction lines should be adequately separated to
prevent unnecessary turbulence.

3.3

PROTECTION DEVICE

The bellhousing installed by the Manufacturer is made of an aluminium die-casting, fastened
to the motor by screws, duly shaped to prevent fingers from coming into contact with moving
parts. It can be removed only by using a proper tool. In case of alignment of pump with mo-
tor on a baseplate, a coupling guard is installed; it is made of a strong metal plate and fas-
tened to the baseplate by screws. Both solutions prevent fingers from coming into contact
with moving parts and can be removed only by using a proper tool.

3.4

ADDITIONAL DESCRIPTION OF ACCESSORIES

3.4.1

Seal parts

The  pump  is  usually  supplied  equipped  with  mechanical  seal.  If  the  Customer  requires  a
particular  type  of  seal,  VARISCO  S.r.l.  installs  the  desired  seal  after  verifying  if  its  dimen-
sions  are  compatible  with  those  of  the  pump.  In  case  the  Customer  requires  only  the  seal
mark, the Company leaves the Manufacturer to select the type of seal, by giving information
about the pumped liquid.

Among the seals used we can mention the following:

single mechanical seal;

- double tandem mechanical seals with tank and pressureless flowing liquid;
- double opposed mechanical seals with external pressurized flowing liquid.
These last must be installed when the pumped product has characteristics which prevent it
from being used as flowing source or for greater safety (visual inspection).

The tank for tandem mechanical seals is not pressurized and it is used to avoid dry opera-
tion of the external seal and visually detect any possible leakage of the internal mechanical
seal.

For magnetic drive pumps sealing is only ensured by static gaskets, since the pump shaft is
completely enclosed within the pump body.

3.4.2

Safety valve

The pump can be equipped with a safety valve, with adjustable calibration, installed on the
rear cover.