Bush WV 1200 A, Инструкция по эксплуатации

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2.3 Shaft Sealing Variants
2.3.1 Mechanical Seal
The shaft sealing consists, in standard execution, of a mechanical seal.
2.3.2 Lip Seals (Optional)
Optionally, the shaft sealing may consist of three lip seals. This variant requires an oiler
(OR) in order to continuously lubricate the sealing system.
2.4 Accessories
NOTE
Depending on the ATEX classification of the machine, some of the following accessories
may be mandatory, see
ATEX Classifications and Associated Accessories [ ► 9] .
2.4.1 Resistance Thermometer
The resistance thermometer monitors the exhaust gas temperature.
Warning and trip signals must be set, see Wiring Diagram Resistance Thermometer [ ► 19] .
2.4.2 Active Bypass Valve
The active bypass valve allows the gas to flow (forced bypass) when the absolute inlet
pressure (P1) is above 100 hPa (abs.).
The active bypass valve is controlled mechanically by a double activated pneumatic cylin-
der.
A pressure switch/transmitter and a directional control valve (not delivered) must be installed to
control the active bypass valve, see
Pneumatic Connection (with Active Bypass Valve only)
[ ► 13]
.
The limit switch (GS/0601) detects the position of the active bypass valve. See Wiring
Diagram Limit Switch [ ► 20] .
X
P1
P1
GS/0601 GS/0601
P1 <100 hPa = free bypass P1 >100 hPa = forced bypass
- the active bypass valve is released
- the limit switch signal can be ignored
- the vacuum booster is running - the active bypass valve is forced in high position
- the limit switch (GS/0601) validates the high
position of the bypass
- the gas flow goes through the bypass channel
- the vacuum booster does not operate
NOTE
The active bypass valve can be substituted by an external bypass (not delivered), see
P&ID "Piping and Instrumentation Diagram" [ ► 9] .