Technological and service facilities of the laboratory
After extending the Laboratory to what
we can see at present, i.e., after rebuilding the workshop wing, offices,
meeting room, the tower housing filters and gust muffler at the environmental
tunnel entrance, and the water basin for the water supply for the vacuum pumps,
the layout has changed as apparent from figures below. The Laboratory main
building is directly attached to the front portal of the gallery.
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The laboratory in 1964 |
The Laboratory layout in 2005 |
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The vacuum pump room |
The vacuum storage is formed by two almost parallel interconnected
galleries with a total volume of 6300 m3 . It begins about 30 meters behind
the front portal, in the unweathered compact rock, 65 meters beneath the rock
top. Both galleries are hermetically sealed by air-tight partitions. One of
the galleries is connected with the wind tunnels by a duct 900mm in diameter.
In the entrance part of the gallery there is the vacuum pump room with three
water-ring 55kW vacuum pumps, type SLOVPUMP 200-SZO-500. Their inlet pipes are
attached to the main 900mm duct. The vacuum pumps have a closed water supply
system, including 3 auxilliary pumps, reservoir in the new Laboratory building,
filters, and a cooling tower. The attainable vacuum is 0.1 x 105 Pa.
The main duct and the wind tunnels
are separated by quick-closing/opening valves (room
4). The largest wind tunnel for cascade research has a quick-slide-valve
600mm in diameter; and being pneumatically controlled it can open or close
the vacuum storage in less than 0.5 sec. The other wind tunnels are attached
to the same main duct; the smaller tunnels by a pipe 300mm in diameter, closed
or opened by a similar pneumatically controlled slide valve. The modular wind
tunnel has a quick- operating ball valve 600mm in diameter. All the quick-operating
valves are secured by manually or electrically controlled slide valves of
the same diameter. The compressed air for the control system has a pressure
of 700 kPa; the compressor room is in the close neighbourhood of the valves.
All wind tunnels are of the intermittent
type, breathing the atmospheric air through a silicagel dryer, and pebble
and cloth filters. Altogether 5 tons of active silicagel are placed in inclined
beds 300mm thick with a permeable bottom (figure below). The total front area
of the beds is 25 m2, so that the air velocity even at maximum airflow does
not exceed 1 m/s, ensuring thus very low losses. The flue-solid particles
from the dryer are caught by the filters – the pebble filter, 100mm
thick, front area 24 m2, and the cloth filter made of firon. Even in the filters
the velocity is less than 1 m/s. From the filters the air enters the inlet
chamber (room 3). Entrances to all wind tunnels
can be individually closed, to prevent sucking air into the inlet chamber
through the idle wind tunnels, as well as to close the wind tunnels during
the silicagel regeneration (i.e. drying). The process of silicagel regeneration
is carried out by hot air, heated up to160 oC by an electric oven, and since
2005 it is fully automatic. During this period, as well as, during the time
the Laboratory is out of operation, the air entrance is closed by perfectly
sealed and insulated entrance gates (figure below).
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Inlet gate with the silica
gel dryer |
Silica gel beds in the dryer |