Working Principle - Danfoss Intelligent Purger System User Manual

User Guide | Intelligent Purger System (IPS) for Ammonia - Technical data, installation, and use

Working principle

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The Danfoss IPS is factory-tested and ready for
use in ammonia plants with a condenser pressure
of more than 6 bar (87 psi) . The purger is charged
with 500 gram (17 .637 oz) of R404A .
Only 2 mechanical connections are needed for
the purger (see fig . 1) . The exchange of ammonia/
NC gases with the main plant is done through
the flange for ammonia access (see 11 in figure
below), while the NC gas purge is done through
the blow-off pipe after the purge solenoid valve
(15)
Through the flange for ammonia access (11), a
mixture of ammonia gas and NC gases enters the
evaporator (10) of the purger .
This ammonia/NC mix is cooled down below
the condensing temperature of the ammonia
by the R404A circuit . At this point, ammonia gas
condenses and returns to the ammonia plant via
gravity, whereas the NC gases accumulates in the
evaporator (10) for subsequent purging .
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Fig. 1 - Purger R404A lay-out
1 Compressor R404A
2
Safety Switch
3 Condenser coil
4
Fan
5 Fan control
6
Liquid reciever
7 Filter
8 Sight glass
9 Expansion valve
10 Evaporator R404A
11 Flange for ammonia access
12 Pressure transmitter R404A
13 Pressure transmitter - Ammonia
14 Temperature sensor - Ammonia
15 Purge solenoid valve
R404A charge 500 gram (17 .637 oz)
By condensing the ammonia gas, a new
ammonia/NC gases mix is naturally pulled
through . This new mix is separated through a
continuous process .
While the NC gas concentration in the evaporator
(10) increases, the R404A evaporator pressure
and temperature will continuously lower .
The controller monitors R404A evaporator
pressure and ammonia pressure and temperature
and when R404A pressure reaches a predefined
pressure differential to the ammonia pressure/
temperature, it prepares to purge the NC gases
through the solenoid valve (15) . The blow-off
is activated by the solenoid (15) and through
appropriate piping/hosing, it is led into a water
bath . This process is done to retain small amounts
of ammonia (see Installation section) .
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© Danfoss | DCS (hhr) | 2019.02
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