Ulvac DIS-252 - Air-Flush Closed Operation; Start-Up

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Important
If it takes time to reach ultimate pressure of pump during initial operation (also operation
after pump has not been used for a long time),
Close inlet, and continue operation for 6~8 hours while opening inlet for 3~5 seconds to atmosphere 2~3 times
per hour. During pump stoppage, moisture might have entered inside of pump and deteriorated performance to
reach ultimate pressure.
If pump has evacuated liquid such as water or high humid air (over 60%RH),
Moisture can deposit inside pump and cause pump failure. In that case, close isolation valve, and open inlet to
atmosphere for 3~5 seconds several times and exhaust moisture inside pump to outside.
If pump has continued operation around ultimate pressure or continuously evacuated high
humid gas
Moisture can be condensed and remain inside pump, causing insufficient ultimate pressure and failure.
In that case, do air-flush operation in accordance with 4.2 [page 22].
4.1 Air-flush closed operation
4.1.1 Start-up
①
Check that blank flange of outlet have been removed.
②
Close isolation valve in order to prevent the drawback of debris attached to the
inside of vacuum pump into vacuum chamber due to pressure differential,
resulting in vacuum break and pollution.
(Open leak valve if you use leak valve).
③
Turn on vacuum pump.
Please install an external power switch or protective device (breaker) before
letting vacuum pump operate.
④
Check start-up of vacuum pump and open isolation valve (close leak valve soon
after start-up if you use leak valve) and evacuate vacuum chamber.
Important
When continuously operating pump at around ultimate pressure (for example, using as fore
line pump of turbo molecular pump) ,
It can cause foreign objects or moisture to deposit inside pump, resulting in failure.
In that case, do air-flush opened operation or close isolation valve and open inlet to atmosphere for 3~5 seconds,
3~5 times daily.
Be careful not to damage air-flush port (especially air-muffler section).
If not, it can cause failure.
When doing air-flush opened operation,
Noise level will increase (by 7~8dB).
Install pump in an area which is not exposed to debris such as iron powder, stone powder,
polish powder or wood dust.
Debris can clog air-muffler, undercutting air-flush effect.