Startup; Checking The Tightness - Grundfos Vaccuperm VGA-111 Installations- Und Bedienungsanleitungen

6. Startup

Warning
The chlorine gas dosing system can only be started
after its good condition has been checked by an
expert, see 2.3 Qualification of the
especially gas-leading parts have been checked for
their tightness.
Check the tightness of the entire system before start-up.
Check the tightness of the valves using ammonia water (small
plastic bottle). White mist indicates leakages.

6.1 Checking the tightness

Due to the heavy corrosiveness of humid chlorine gas, leakages
increase quickly. Therefore, even the smallest leakage must be
eliminated immediately.
Warning
Check the tightness only if the entire system is ready
for start-up.
Danger of chlorine gas leakage!
6.1.1 Checking the chlorine solution lines and the injector
Observe the installation and operating instructions of the injector.
6.1.2 Checking the vacuum lines
Vacuum lines are all lines between vacuum regulator and injector.
1. Close all chlorine container valves.
2. Close the rate valve.
3. Open the shut-off valve at the injection unit.
4. Open the motive water valve.
5. Switch on the booster pump.
6. Open the rate valve.
– If the floater shows a gas flow, or the vacuummeter indicates
more than -9 m water column, the vacuum lines are leaky.
7. Close the rate valve.
8. Switch off the booster pump.
9. Close the motive water valve.
10. Close the shut-off valve at the injection unit.
11. Check the vacuum lines and connections. Re-tighten them
carefully, if necessary.
12. Repeat the tightness check.
– If the floater shows no gas flow, and the vacuummeter
indicates -9 m water column or less, the vacuum lines are
tight.
Reasons for insufficient operating vacuum:
Note Injector too small, defective, or blocked.
Booster pump too small, or defective.
6.1.3 Checking the gas pressure lines
Gas pressure lines are all lines leading from the chlorine gas
containers to the vacuum regulator.
1. If the system is equipped with a nitrogen rinsing device, check
the tightness roughly with nitrogen.
2. Detailed checking is made with ammonia.
16
Checking the tightness with nitrogen
1. Close all chlorine container valves.
2. Open container connection valves and all shut-off valves up to
the chlorine gas dosing system.
3. Open the connection valve of the nitrogen cylinder.
users, and
4. Slowly open the valve of the nitrogen cylinder, until the lines
have a pressure of about 10 bar (read at the pressure gauge
of the vacuum regulator).
5. Apply soap water to all components under pressure.
– If bubbles form and/or pressure drops at the pressure
gauge, the pressure lines are leaky.
6. Depressurise the system.
7. Eliminate the leakage.
8. Repeat the tightness check.
9. If no bubbles form, and the pressure at the pressure gauge
does not drop significantly within one hour, the pressure lines
are tight.
Checking the tightness with ammonia
Fig. 13 Hazard notes for ammonia
Even very small leakages become evident with ammonia vapour,
which reacts with chlorine gas forming white mist.
Warning
Maximum nitrogen pressure 16 bar.
Danger of damages and leakages when being
exceeded.
Warning
Ammonia is irritating to eyes, respiratory system and
skin.
Ammonia is very toxic for water organisms!
When checking the tightness with ammonia, wear
tight protective goggles, gloves and clothes.
Warning
Liquid ammonia must not come in contact with lines
or parts of the system, because it is very corrosive.
Remove drops immediately with a dry cloth.