LEVEL PROBES FOR ATMOSPHERIC PRESSURE TANKS
Different overfill probes for liquid hydrocarbons :
DOCIL C400 probe : Overfill probe with optical sensor
MCG 1090 probe : Overfill probe with mechanical sensor
DNM600 or DNC600 probe : Overfill probe for tank with internal floating screen or floating roof
DOCIL C 400 OPTICAL OVERFILL PROBE
TYPES OF MOUNTING :
Mounting on external nozzle (on tank shell)
Mounting on roof nozzle
ADAPTABILITY :
Sensor settings on the DOCIL 400 probe can be altered at will.
TESTABILITY :
The DOCIL C 400 probe is the only system on the market with a built-in “real time” functional testing device; the product stored in the tank is injected into the device.
The probe test is performed with the tank in operation; there is no need to dismantle the probe.
SIMPLE WIRING :
A single one-pair cable (such as 01-IP-09-EG-FA) is necessary to connect a probe with one or two sensors to the processing system.
POSSIBLE CONFIGURATIONS :
DOCIL C 400 C probe:
Probe fitted with one level sensor (e.g. HL)
The information is processed with a 9533 board
DOCIL C 400 D probe :
Probe fitted with two level sensors (e.g. HL and HHL)
The information is processed with a 9533 board
DOCIL C 400 E probe :
Probe fitted with three level sensors (e.g. CTL, HL and HHL)
The information is processed with two 9533 boards
ATEX :
- Category & zone : || 1 G
- Electrical protection : Ex ia ||C T5 Ga
- Ambient use temperature : -20°C to +60°C
- Installation location : Zone 0, 1 or 2 GAS
DOCIL SENSOR - LARCO
The DOCIL sensor comprises a glass cone and an electronic circuit with, among other things, an infrared luminous signal transmitter and a receiver.
The DOCIL sensor works on the optical reflection/refraction principle.
DOCIL sensor characteristics
- Accuracy: 0.1 mm
- Response time: 1 ms
- ATEX : II 1 G Ex ia IIC T5 Ga
When the glass cone is not immersed in the liquid, the optical signal is reflected entirely towards the transmitter :
Conversely, when the cone is immersed in a liquid (hydrocarbon), the luminous signal is refracted and the receiver no longer receives the signal, thereby triggering an alarm :
DETECTOR MCG 1090 Mechanical sensor anti-overspill detector
TYPES OF MOUNTING :
Mounting on fixed roof and floating screen tank
Mounting on fixed roof without internal floating screen
ADAPTABILITY :
Detection heights can be altered at wil
TESTABILITY :
The MCG1090 probe can be fitted (optional) with a remote check test mode
There is no need to dismantle the probe nor fit it to the tank roof for the test (can be tested directly from the processing cabinet)
ATEX :
Category& zone : || 1/2 G Ex d ||B T6
Ambient use temperature : -20°C to +40°C
Installation location : Zone 0, 1 or 2 GAS
Out of the hydrocarbon, the weight of the floats pulls the magnetic rod towards the bottom of the probe :
The HL and HHL reed dry contacts are not loaded
No alarm is activated
When the floats are immersed, there is less apparent weight on the line due to the buoyant force.
The magnetic rod is pushed upwards inside the probe by the retraction force of the spring
The first alarm is triggered when the rod goes past the first dry contact (e.g. NH)
The first alarm is triggered when the rod goes past the second dry contact (e.g. NTH)
DNM/DNC600 OVERFILL PROBE
ATEX:
- Category & zone : II 1 G
- Electrical protection : Ex ia IIC T5 Ga
- Ambient use temperature : –20°C to +60°C
- Installation location : Zone 0, 1 or 2 GAS
TYPES OF MOUNTING :
Roof nozzle
Fixed roof tank with internal floating screen
Floating roof tank
ADAPTABILITY:
DNM 600 :
Optical sensor adjustments at will
Mechanical contact switch adjustments at will
DNC 600 :
Mechanical contact switch adjustments at will
Devoid of optical sensors
TESTABILITY :
DNM 600 :
Fitted with an optical DOCIL C probe with “real time” testing by injecting hydrocarbon into the orifices provided for this purpose
The mechanical contact switches can be tested by simple manual action
DNC 600 :
Fitted with mechanical contact switches only, the equipment can be tested by simple manual action
SIMPLE WIRING :
DNM 600/ DNC600 :
Only two one-pair cables (such as 01-IP-09-EG-FA) are necessary to connect a probe with one or two detection thresholds to the processing system.
POSSIBLE CONFIGURATIONS :
DNM600 :
Probe fitted with one or two redundant optical sensors of one or two mechanical contact switches
The information is processed with two 9533 boards
DNC 600 :
Probe fitted with one or two mechanical contact switches only
The information is processed with a 9533 board
PRINCIPLE OF THE DNC 600 PROBE
1. The product level is underneath the detection thresholds :
- The DNC 600 probe is not resting on the floating roof
- The mechanical contact switches are not activated
2. The product level reaches the first detection threshold :
- The DNC 600 probe is resting on the floating roof
- The first mechanical contact switch is activated
3. The product level reaches the second detection threshold :
- The DNC 600 probe is resting on the floating roof
- Both mechanical contact switches are activated
PRINCIPLE OF THE DNM 600 PROBE
1. If the screen or floating roof rises with the product level :
- The DNM 600 probe rests on the roof
- The more the roof rises, the more the probe slides in its bracket
- By sliding in its bracket, the probe activates the mechanical contact switches carefully positioned on the bracket
- The alarms are tripped at the desired level thresholds
2. If the screen or floating roof sinks :
- The DNM 600 probe fitted with optical sensors provides safety redundancy
- The optical sensors will trip alarms when the product rises in the tank
9533 SIL2 PROCESSING BOARD
The 9533 board has an electronic architecture based on widespread discrete components and three relays. The board can be used to process information from any LARCO detector.
Not only does this board process detection information and detector faults, it also constantly monitors a line that can perform quick and efficient troubleshooting in a system fault.
The 9533 board has four indicator lamps on its front face; the different combinations give precise information on the state of the detector.
The 9533 board delivers three dry contacts that can be recovered directly by the site’s PLC:
One contact N1 (level 1)
One contact N2 (level 2)
One contact D (fault)
NECESSARY INFORMATION
Tank type (fixed or floating roof tank, with or without internal floating screen, etc.)
Nozzle type (on tank roof, on shell)
Nozzle and mounting flange diameter (flange can be supplied by LARCO)
Product stored
Probe length
User site