Speck Pumpen Vakuumtechnik GmbH
zertifiziert: DIN EN ISO 9001
Supplementary Operating Instructions for Explosion Protection
11
7.2.3 Inertisation with the conveying of gases and vapours, which contain hydrogen
The liquid-ring compressor is run by means of an appropriate start-up and rundown procedure so that no
hydrogen-air mixture exists in the standing machine. Before the beginning of the process and before the
stoppage, the compressor is flushed with inert gas.
With malfunctions the compressor is immediately decoupled from the process, flooded with inert gas and
then switched off.
Start-up procedure:
The valves on the process side GO 11 and/or GO 12 (comp. Fig. 5.1/5.2) are closed.
After inspection for the absence of malfunction and the clearance to start by LS- 01 or LS- 02 (comp. Fig.
6.1), an appropriate time lag is necessary for the activation of the flow rate switch FS- 04. The time lag
depends on the size of the compressor, the intake pressure and the viscosity of the operating liquid. It is
between 5 s und 90 s. (see data sheet).
After a failure-free start-up of the liquid-ring compressor the nitrogen-flushing valves UV 13 and/or UV 14
open for a flushing time according to table 6.1. It must be flushed at least with the 5-fold, internal, free
volume of the vacuum system. The clearance occurs with the closing of the nitrogen-flushing valves
UV 13 and/or UV 14. The valves on the process side GO 11 and/or GO 12 can now be opened. The start-
up procedure is concluded.
Operation:
With failure-free operation no further activities are required. The liquid-ring compressor is monitored by
the existing monitoring organs.
Rundown procedure:
After the end of the process first the process valves GO 11 and/or GO 12 are closed. While the liquid-ring
compressor continues to run, the nitrogen-flushing valves UV 13 and/or UV 14 open for a preset time.
The flushing time is determined on the basis of the minimum pressure and the minimum quantity of flow.
The flushing time is 5-fold of the free, internal volume of the vacuum system. After the conclusion of the
flushing time the nitrogen valves UV 13 and/or UV 14 close. The liquid-ring compressor is switched off.
Malfunction:
If a malfunction occurs through the activation of one or several monitoring organs, then the process
valves GO 11 and/or GO 12 close immediately. At the same time the nitrogen flushing valves UV 13
and/or UV 14 open for a preset time. For the inertisation, a minimum volume must flow through the
compressor, which corresponds to 5-fold the internal volume of the system. After the flushing procedure
the compressor is to be switched off.
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