User Guide
|
Intelligent Purging System (IPS 8) for Ammonia - Technical data, installation and use
8 | BC306932151284en-000201
© Danfoss | DCS (ms) | 2020.01
Air traps
Fig. 4 Liquid level. Bottom connected receiver
Fig. 5 Liquid level. Top connected receiver
For systems with low pressure liquid level control,
the correct condenser/ receiver installation is as
shown in Fig. 4 and Fig. 5.
The discharge gas from the compressor (1) is
led to the condenser (2) where it is condensed.
The receiver (3) holds the liquid until there is a
demand for liquid from the LP side, e.g., until the
expansion valve (4) opens. If the expansion valve
is closed, the liquid condensed in the condenser
will need to be stored in the receiver and the
level will increase. To ensure a free flow to the
receiver, the gas must be allowed to leave the
receiver; this process is accomplished through
the pressure equalizing line (a). The pressure
equalizing line makes the pressure in the receiver
the same as in the compressor discharge line.
The pressure in the condenser outlet is lower due
to the pressure loss in the condenser. Since the
condenser outlet pressure is lower than in the
receiver, it is therefore necessary to mount the
condenser higher than the receiver and allow for
a higher liquid level in the piping between the
condenser and the receiver (b).
The liquid column in the line (b) compensates for
the pressure difference between the condenser
outlet and the receiver.
Fig. 4 shows the liquid connection at the bottom
of the receiver.
If the liquid from the condenser is connected to
the top of the receiver (Fig. 5), a slightly different
arrangement must be made.
The liquid line (b) from the condenser to the
receiver will need to have a goose neck/liquid
trap to ensure that the liquid column is actually
established.
As air is heavier than ammonia gas, the air will
collect in two locations in this type of installation:
On top of the liquid in the receiver (x) and/or
on top of the liquid in the drop leg from the
condenser (y).
