Carrier Graviner Mk7, Инструкция по установке, эксплуатации и обслуживанию

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March 2021 Page 8 of 143 59812-K007 Rev 17
Business Confidential
1.4 SYSTEM OVERVIEW
The Graviner Mk7 OMD is an auto addressed oil mist detection system capable of monitoring up to 10
Control Units per system with each Control Unit having up to 10 detectors connected to it. This is
achieved without external sample pipes and with minimum cabling. Each detector head monitors a single
crank space and is a stand-alone device. On power up the detectors gather oil mist density data and
convert it to a digital signal for transmission via the data lines in the detector cable to the Control Unit
which is also mounted on the side of the engine. Alarm levels and alarm output requirements are all set
from either the Remote Display Unit or a PC connected directly to the Control Unit.
The Remote Display Unit n display that shows the oil mist level for each
engine and when required each detector, as well as the status of the system. In the event of an alarm,
the display immediately shows the oil mist levels for the relevant engine. It also enables the individual
readings of each detector on the engine to be displayed on demand and automatically under alarm
conditions.
In the event of a detector fault, that detector can be isolated without affecting the function of the other
detectors on the engine. The system will continue to operate while the faulty detector is replaced,
repaired or maintenance is carried out.
The Mk7 detectors use optical sensing;
the oil mist density in the crank space to which it is connected. In addition, the detector automatically
performs self-checks for any internal faults. The Control Unit interrogates each detector in turn,
identifying the position connected at the Control Unit, the oil mist density value and determines the status
of the detector.
Each detector is fitted with 3 LED indicator lights:
Green - Power on
Red - Alarm
Amber - Fault
As all detectors operate independently, the loss of one detector through a fault does not affect the
operation of the remaining system. Individual detectors, or engine groups, can be isolated from the
system for maintenance while the rest of the system remains in operation.
The Control Unit can be supplied with or without a control membrane. The control membrane has LED
indication for detectors connected, push buttons for isolation and de-isolation of detectors, as well as
pushbuttons for Accepting and Resetting Alarms.
Alarm Philosophy
The system has 3 separate alarm levels as detailed below
1. Pre-Alarm - This indicates that the oil mist levels are increasing in a particular crank-space and
that investigation should be undertaken. This alarm will not operate the slowdown/shutdown
relays.
2. Engine Slow/Shutdown Alarm - When any detector reaches this threshold then the
slowdown/shutdown relay will be operated if they are connected.
3. Back Up Alarm - In the event of a failure of either the Pre-Alarm or Engine Slow/Shutdown
Alarm, then the Back Up Alarm will operate, but it will not operate the slowdown/shutdown
relay. This is an additional functional precaution added by Carrier Fire & Security UK Ltd which
can be connected in any way the customer requires. This is usually connected to a warning
beacon or siren; however, the customer may choose to connect the relay to another device or to
the engine slowdown or shutdown circuitry.
On receipt of either a Pre-Alarm or Engine Slow/Shutdown Alarm the engine should, unless connected
to a slowdown/shutdown relay, be stopped if safe to do so and allowed to cool down so that the
background oil mist levels reduce before entering the engine room.
When the oil mist levels have returned to normal then the Accept and Reset buttons can be operated
from the Control Unit membrane if fitted or alternatively from the Remote Display Unit and the system
will then return to normal operation.