Operating Conditions; Maximum Ambient Temperature; Maximum Liquid Temperature - Grundfos CR series Montage- Und Betriebsanleitung

8. Operating conditions

DANGER
Explosion risk
Death or serious personal injury
- Ensure that the required minimum inlet
pressure is always available.
See the CR, CRI, CRN installation and operating
instructions:
– http://net.grundfos.com/qr/i/96462123
– http://net.grundfos.com/qr/i/99078486
DANGER
Explosion risk
Death or serious personal injury
- Do not operate the pump with higher
liquid temperature than the maximum
liquid temperature (t
pump nameplate.
- The calculated maximum permissible
liquid temperature must not be
exceeded.

8.1 Maximum ambient temperature

The maximum ambient temperature for the pump:
-20 to +60 °C.

8.2 Maximum liquid temperature

In normal pump operation, the highest temperatures
are to be expected at the surface of the pump casing
and at the shaft seal. The surface temperature will
normally follow the temperature of the liquid.
You can calculate the permissible liquid temperature
by finding the maximum permissible temperature at
the surface of the pump during operation in the table
shown in section 8.3.1 Temperature
reduce it with the temperature contribution from shaft
seals, see table in section
temperature.
Section 8.3 Temperature calculation
diagram which shows how the maximum surface
temperature depends on the liquid temperature and
the temperature contribution from the shaft seal.
Calculation example
Based on temperature contribution from a HQQX
shaft seal, media class 1, shaft diameter ∅22 and
pressure 2.5 Mpa.
Temperature class (T4) = 135 °C, see section
8.3.1 Temperature class.
Temperature contribution from HQQX shaft seal = 24
°C, see section 8.3.2 Shaft seal
Safety margin for Group II = 5 °C according to the
ATEX standard.
10
) stated on the
max
class, and
8.3.2 Shaft seal
contains a
temperature.
Result
Maximum permissible liquid temperature:
T4 - contribution from shaft seal - safety margin =
135 - 24 - 5 = 106 °C.
Pumps, that are allowed to pump liquids up to a
maximum of 150 °C, are equipped with a tandem
shaft seal. In this case, the temperature and flow rate
of the flushing liquid must be according to the
description in the installation and operating
instructions "CR, CRI, CRN - Double seal (tandem)"
at http://net.grundfos.com/qr/i/96477555.
Make sure that the combination of CR pump and dry-
running protection is described in the explosion
protection document according to the directive 1999/
92/EC.
The responsibility for checking the correct
flow rate and the temperature of the
flushing liquid rests with the installer or
owner.