Mill-Gard Brochure.indd

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					Mill - Gard

The Mill-Gard range of Carbon Monoxide detection systems provide early warning of a fire within coal pulverizers
and silo’s. Designed specifically for detecting C.O. gas emissions due to smouldering or fire, the systems use
powerful pumps to extract air samples from the coal mills or silo’s via hardened probes. The air samples are
conditioned and passed over industrial grade C.O. sensors to quickly detect an increase in gas levels. Any
increase in C.O. levels provides an early indication of fire, and alarms are raised accordingly.



                   Key features of the Mill-Gard range:            All systems are designed to minimise
                                                                   purchase, installation, operation and
                                                                   maintenance costs:

                   •   Options for monitoring from 1-16            •   Low purchase cost: multiple points can be
                       sampling probes                                 monitored using one gas sensor
                   •   Continuous sampling or sequential           •   Low cost of ownership: minimal numbers
                       multipoint systems                              of gas sensors to be maintained
                   •   High flow pumps provide fast response        •   Self cleaning operation: all systems
                   •   Conditions the air samples to remove coal       contain dust/water filters, with auto drain
                       dust and contaminants                           function
                   •   Adjustable sample and purge times
                   •   Sample line back-purge facility
                   •   Dual sensor option
Mill - Gard
The Need for C.O. Detection                                                    Control System

Coal for use in the combustion process is delivered to the                     Air samples are drawn into the control cabinet using
power station, unloaded into hoppers and stored in coal                        powerful high-flow pumps. The air samples are filtered and
silo’s. Coal is fed from the silo’s at a predetermined rate                    passed across either one or two C.O. sensors. The C.O.
by a feeder to the mill where it is pulverized and forced                      sensors are monitored by a control panel which displays
through a classifier. The classifier grades the coal allowing                    the gas levels, activates alarm relays and sends status
only fine particles to pass through to the burners. In all of                   signal to the customer control centre via digital signals
the areas described there is a real risk of spontaneous                        and/or an RS-485 Modbus link.
combustion of coal dust.
                                                                               Each sample probe is sampled by its own pump and
Prior to combustion, smouldering occurs which emits                            monitored by a dedicated sensor on continuous monitoring
detectable levels of carbon monoxide gas. At this stage                        systems. Thus all sample lines on multi-point systems are
there is no fire so prevention actions can be taken. The                        fully independently controlled enabling any point to be
Mill-Gard system is designed to detect low levels of C.O.                      taken off-line for maintenance without affecting the rest of
gas and warn site operators of any impending fire hazard                        the system.
before combustion occurs.
                                                                               Multi-point sequential systems use a common pump and
                                                                               sensors to monitor all sample lines on a sequential basis.
System Description                                                             Each sample line is monitored for one minute.

The Mill-Gard systems comprise a control cabinet and                           Sample lines are back-purged using high pressure air. The
sample probes which are inserted into the coal mill or silo                    purge periods can be adjusted to suit site conditions. The
to extract air samples.                                                        system constantly monitors sample flow from all lines and
                                                                               will produce a fault signal in the event of a blockage.
Typical probe installation
                                                          COAL DUST PIPELINE
                                                                               Minimal maintenance is required. The systems are
                                                                               designed so that all filters are easily accessible, and
                                                                               calibration is facilitated using an easy-to-follow menu.

                                                                               Crowcon can supply a comprehensive ‘SCADA’ type
                    SAMPLE




PROBE ASSEMBLY


                                                                               monitoring system to provide remote display of system
                                      DIRECTION OF FLOW
DETECTION SYSTEM
 SAMPLE LINE TO




                                                                               status, alarm warnings, data-logging, SMS messaging and
                                                                               access to information via the internet.

                                                                               Systems can be tailored by Crowcon’s experienced
                                                                               engineering team to suit site requirements. Contact
                                                                               Crowcon for pricing and information.




                                                                                                Typical Multi-point System
Mill - Gard
Single Point Sample System
                                           The single point system is designed to monitor gas samples from a single
                                          probe. A powerful high-flow pump extracts and transports gas samples to
                                          the system where they are conditioned to remove dust and moisture. The
                                          conditioned sample gas is then passed across one or two gas sensors before
                                          being exhausted to atmosphere.

                                          System integrity is maintained at all times using flow-fail monitoring devices.
                                          The system is controlled by a programmable timer which sequences sample
                                          and purge/drain cycles. The current operating mode is clearly displayed and
                                          sample/purge times are fully adjustable.

                                          The gas sensors are monitored by an optional Gasmaster control panel which
                                          provides gas level display, alarm and fault indication, relay outputs and 4-20mA
                                          outputs for each sensor plus RS-485 Modbus communications. Alternatively
                                          the system can be supplied without the Gasmaster and provide a 4-20mA
                                          signal from each sensor plus a system fault contact.




Multi Point Sample System
The multi-point system uses the same sampling arrangement as the single point system,
but can monitor up to 16 separate sample lines on a sequential basis.

Each sample line is monitored for one minute on a sequential basis, and the samples are
passed across one or two gas sensors. Filters and flow-fail devices are fitted to ensure
safe and reliable operation at all times. Sample and purge times are fully adjustable,
and a specific sample line can be selected and held at any time using buttons mounted
on the front panel.

The gas sensors are monitored by an optional Gasmaster control panel which provides
gas level display, alarm and fault indication, relay outputs and 4-20mA outputs for each
sensor plus RS485 Modbus communications. Alternatively the system can be supplied
without the Gasmaster and provide a 4-20mA signal from each sensor plus a system fault
contact.



Continuous Multi Point Sample System

                        The continuous multi-point system has a pump, filter and valve set and C.O. sensor dedicated for each
                        sample line. Thus up to 15 sample points can be concurrently monitored to provide rapid warning of
                        gas build-up in any area.

                        Each sample line is monitored by a flow-fail device to ensure integrity at all times. Sample, purge and
                        back-purge times are adjustable, and any sample point can be taken off-line for maintenance whilst the
                        remaining lines remain operational.

                        The gas sensors are monitored by a Vortex control panel, which provides gas level display, 3 levels of
                        alarm and a fault indication, 8-32 programmable relay outputs and RS-485 Modbus communications.
                        A software package is also available to provide a remote display of gas levels and system status, alarm
                        warnings, datalogging, SMS messaging and access to information via the internet.
Mill-Gard Range
Specifications

 Model                                    Single Point                                                    Sequential Multi-Point                          Continuous Multi-Point
 Sample Lines                             1                                                               1-16                                            1-15
 Gas sensors                              1 or 2                                                          1 or 2                                          1 or 2 per sample line
 Dimensions                               760 x 600 x 350mm                                               1000 x 600 x 400mm                              2100 x 800 x 800mm
                                          (30 x 23.5 x 14 inches)                                         (39.3 x 23.5 x 16 inches)                       (83 x 31.5 x 31.5 inches)
 Ingress protection                       Indoor use only                                                 Indoor use only                                 Indoor use only
 Sample Pipe Specification                 10mm o/d, 8mm i/d                                               10mm o/d, 8mm i/d                               10mm o/d, 8mm i/d
                                          (1/2” o/d optional)                                             (1/2” o/d optional)                             (1/2” o/d optional)
                                          Stainless Steel, HDPE or PTFE                                   Stainless Steel, HDPE or PTFE                   Stainless Steel, HDPE or PTFE
 Max. line length                         1Km                                                             1Km                                             1Km
                                          (0.62 mile)                                                     (0.62 mile)                                     (0.62 mile)
 Sensor type                              Electrochemical                                                 Electrochemical                                 Electrochemical
                                                   o                                                                       o                                      o
 System operating                         0 to +35 C                                                      0 to +35 C                                      0 to +35 C
                                                   o                                                               o
 temperature                              (32 to 95 F)                                                    (32 to 95 F)                                    (32 to 95oF)
 Sampling performance                     Suitable for sampling from                                      Suitable for sampling from                      Suitable for sampling from
                                          -600mbar(g) to                                                  -600mbar(g) to                                  -600mbar(g) to
                                          +250mbar(g)                                                     +250mbar(g)                                     +250mbar(g)

 Operating Voltage                        110V or 230Vac                                                  110V or 230Vac                                  110V or 230Vac
 Outputs                                  System only: 4-20mA for each                                    System only: 4-20mA for each                    8-32 SPCO Relays rated at 5A
                                          sensor plus a fault contact.                                    sensor plus a fault contact.                    250Vac. Can be set for any alarm
                                          With Gasmaster Control System:                                  With Gasmaster control system:                  level from any sensor. Fault relay
                                          High and Low alarm relays per                                   High and Low alarm relays per                   also provided. RS-485 Modbus
                                          sensor, Fault relay, 4-20mA per                                 sensor, Fault relay, 4-20mA per                 communications. Remote display/
                                          sensor plus RS-485 Modbus                                       sensor plus RS-485 Modbus                       data logging software available.
                                          communications. Relays rated 8A                                 Relays rated 8A 250Vac
                                          250Vac
 Display                                  LCD for pneumatic functions.                                    LCD for pneumatic functions.                    LCD for pneumatic functions. LED
                                          Optional Gasmaster shows gas                                    Optional Gasmaster shows gas                    display for gas levels, alarms and
                                          levels, alarms and sensor status                                levels, alarms and sensor status                faults. Comprehensive remote
                                          via a large LCD display.                                        via a large LCD display.                        display software available with site
                                                                                                                                                          mimic option.


 Sensor options                           CO: 0-100, 250, 500 or 1000ppm
                                          Other gases may be available on request.
 Approvals                                Safe area use only                                              Safe area use only                              Safe area use only




Note:   Systems can be engineered to suit any application. Crowcon require that a Sample System Questionnaire is completed prior to ensure the specified system
        meets site requirements. Contact Crowcon for details.

Accessories            Sample probes: Various options available for insertion into the coal mill or silo.

                       Cooling Coil: To reduce sample gas temperature from hot processes

                       10mm HDPE Sample tube: Available by the metre




                                                                                                                                                                          P07 019
                                                                                                                                                                          Issue 1 Feb 07
UK Office                                 USA Office                                                         Rotterdam Office                                 Singapore Office
Crowcon Detection Instruments Ltd        Crowcon Detection Instruments Ltd                                 Crowcon Detection Instruments Ltd               Crowcon Detection Instruments Ltd
2 Blacklands Way                         21 Kenton Lands Road                                              Vlambloem 129                                   Block 192 Pandan Loop
Abingdon Business Park                   Erlanger                                                          3068JG, Rotterdam                               #05-01 Pantech Industrial Complex
Abingdon                                 Kentucky 41018-1845                                               Netherlands                                     Singapore 128381
Oxfordshire OX14 1DY                     USA                                                               Tel: +31 10 421 4232                            Tel: +65 6745 2936
United Kingdom                           Tel: +1 859 957 1039 or                                           Fax: +31 10 421 0542                            Fax: +65 6745 0467
Tel: +44 (0) 1235 557700                       1-800-5-CROWCON                                             Email: eu@crowcon.com                           Email: sales@crowcon.com.sg
Fax: +44 (0) 1235 557749                 Fax: +1 859 957 1044                                              Website: www.crowcon.com                        Website: www.crowcon.com
Email: sales@crowcon.com                 Email: salesusa@crowcon.com
Website: www.crowcon.com                 Website: www.crowcon.com
                                                         Crowcon reserves the right to change the design or specification of this product without notice

				
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