The Turbo Air® 3000 Centrifugal Compressor Compressor Handbook

The Turbo Air 3000 Centrifugal Compressor Operator’s Manual
Block Valve
All compressor installations must include a block valve to insulate the compressor from the remainder of
the pressure system in case of a check valve failure. The user must supply the block valve, which must
be installed after the check valve.
A—16
WARNING:
Whenever the compressor is being serviced, be certain to close and lock the block valve.
These measures are necessary to protect the compressor whenever the check valve is being
serviced or otherwise not functional.
Automatic Block Valve Option
The Automatic Block Valve option fits between two 150-lb. ANSI raised-face flanges in the discharge air
piping. The recommended installation is after the aftercooler (if so equipped) and at least four pipe
lengths beyond the discharge check valve. While the valve orientation is at the installer’s discretion,
accessibility should be considered if the Automatic Block Valve is to be used as a lockout device during
compressor service.
The valve actuator requires a 60-psig air supply for a three-stage compressor or a 30-psig air supply for
a two-stage compressor. If available, use the instrument air supply; alternatively, tap the pipe located
immediately upstream of the valve itself. The supply air should be connected to the lockout valve on
the block valve assembly. Verify correct operation of the Automatic Block Valve at the initial startup,
since valve malfunction may cause compressor surging. Refer to Cooper Turbocompressor EDR-A-008,
Automatic Block Valve, for additional information on the Automatic Block Valve option.
Control Valve Piping
Depending on the control method being applied, the Turbo Air 3000 will either completely or partially
unload whenever the capacity of the compressor exceeds the compressed air system’s demand. Under
AUTO-OFFLINE control, the compressor is unloaded by completely bypassing the compressed air system
and venting discharge air back to the inlet of the compressor or out to atmosphere. In other cases, a
portion of the discharge air is partially vented or blown-off in order to maintain Constant Pressure or
constant mass flow into the compressed air system.
Bypass Valve
The AUTO-OFFLINE Control method utilizes a pop-action bypass valve (BPV). The BPV operates in either a
fully open or fully closed position. The compressor owner/installer is responsible for the proper installation
of this control valve (which is shipped separately) unless the Mounted Bypass Valve option is
purchased. (Refer to the relevant heading for additional information about that option.)
Modulating Blow-Off Valve (MBOV)
All control methods may utilize a modulating blow-off valve (MBOV) which operates in any position
from fully closed to fully open. A pneumatic actuator, and I/P transducer, a volume booster and a filter
regulator all come mounted and integrally piped to the valve body as a complete assembly. The owner/
installer is responsible for the proper installation of the MBOV, which is shipped separately.