Edwards ATEX 1 EHR, Instruction Manual

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TECHNICAL DATA
A750-04-880 Issue F
Your sealing liquid and (if necessary on ATEX Category 2 pumps) seals flush liquid supplies must meet the following
requirements:

If you use a flammable sealing liquid and do not monitor the oxygen concentration, then your pump is ATEX
Category 1 internal. For ATEX Category 2 or Category 3 pumps, you must check the leak tightness of your
system after installation (see
Section 3.16 ) and monitor the oxygen concentration at the process outlet
during operation (see Section 3.4.2 ).

On ATEX Category 2 pumps configured for external seals flush supplies, if the sealing liquid is not the same as
the seals flush liquid, the two liquids must be compatible.

The liquid(s) must be compatible with the process gases and vapours pumped, and with the materials of
construction of the pump (see
Section 2.7 ).

The liquid(s) must not contain any particles larger than those specified in Table 2 .

The pressure of the sealing liquid and (on ATEX Category 2 pumps configured for external seals flush supplies)
the seals flush liquid supplies must be adequate to overcome pressure losses through the supply pipelines.
The pressure of each supply (at the corresponding inlet port on the pump) must be > 0.05 bar (5 x 10
3
Pa)
above the outlet pressure.
When the vapour pressure of the sealing liquid is close to the process inlet pressure, the liquid sealing ring can start
to boil and this may result in cavitation. (Cavitation occurs when vapour bubbles formed at the process inlet are
transferred to the process outlet, where the bubbles collapse under pressure with potentially destructive force.)
You should therefore ensure that the temperature of the sealing liquid supply is as low as possible. If the temperature
of the process gas is > 70
o
C, consult Edwards Application Engineers for advice.
2.6.2 Use of water based sealing liquid/seals flush liquid
If you use a water based sealing liquid or seals flush liquid, where ambient temperatures can fall close to 0
o
C or
below, take appropriate precautions to ensure that the liquid does not freeze and damage the pump.
Such precautions may include the addition of ethylene glycol anti-freeze to the liquid, in concentrations to suit the
climatic conditions. You must not use other types of anti-freeze.
Table 10 - Sealing/seals flush liquid supply data
Sealing liquid/seals flush liquid * pressure > outlet pr 0.05 bar, 5 x 10
3
Pa
Sealing liquid/seals flush liquid * auto-ignition temperature > 160
o
C
Sealing liquid
Maximum viscosity † 1 x 10
-5
m
2
s
-1
Maximum density † 1200 kg m
-3
Minimum conductivity 1000 μ S m
-1
Maximum flow rate See Tables 6 and 7
Maximum temperature 70
o
C
* ATEX Category 1 and 2 pumps configured for external seals flush supplies only.
† Contact your supplier or Edwards if you want to use a sealing liquid with higher density/viscosity.