SABROE SAB 193 S, Инструкция по эксплуатации, Страница: 69 / 177

Engineering manual - SAB 193-233-283 S A-frame (including ATEX)
008831 en 2022.02
69/175
Technical description
Fig. 45: Anti-vibration economiser kit
Fig. 46: Anti-vibration economiser kit
For refrigeration plants employing multiple compressors on a common economising vessel, re-
gardless of economiser type, each compressor must have a back-pressure regulating valve in
order to balance the economiser load, or gas flow, between compressors. The problem of bal-
ancing load becomes most important when one or more compressors run at partial load, ex-
posing the economiser port to suction pressure. In the case of a flash vessel, there is no need
for the redundancy of a back-pressure regulating valve on the vessel and each of the multiple
compressors. Omit the BPR valve on the flash economiser vessel and use one on each com-
pressor, as shown in Fig. 49. It is also recommended that the back-pressure regulating valves,
used on economiser lines, should be specified with electric shutoff option. The electric shutoff
feature is necessary to prevent flow from the common economiser vessel to the suction side of
a stopped compressor, through the suction check valve bypass line, if the other compressors
and the common economiser vessel are still operating and the HV2 valve on the suction by-
pass is open.
For refrigeration plants using a Packaged Refrigerant Recirculation (PRR) unit and a direct ex-
pansion (DX) economiser system, it is necessary to operate the liquid feed solenoid on the
PRR unit and the liquid feed solenoid on the DX vessel off of a common signal to avoid liquid
overfeed on the DX economiser system.
If multiple compressors are operated with a common economiser vessel, it is necessary to in-
stall a back-pressure regulator valve with an electric shutoff option in the vapour line piped to
the compressor's economiser port. If an electric shut-off is not installed in the economiser va-
pour line, valve HV-2 must remain closed to avoid a gas bypass from the economiser line
through the suction check valve bypass, back to the suction line on a compressor that is shut
down.
Economiser kit
optional
Strainer
Shipped loose
Damper
with strainer
Eco. line