LEVEL PROBES FOR ATMOSPHERIC PRESSURE TANKS

Different technologies in line with your applications and needs.

Different overflow probes for liquid hydrocarbons :

DOCIL C400 probe : Overflow probe with optical sensor

MCG 1090 probe : Overflow probe with mechanical sensor

DNM600 or DNC600 probe : Overflow probe for tank with internal floating screen or floating roof

DOCIL C 400 OPTICAL OVERFLOW 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. NTH)
The information is processed with a 9533 board

  • DOCIL C 400 D probe :

Probe fitted with two level sensors (e.g. NH and NTH)
The information is processed with a 9533 board

  • DOCIL C 400 E probe :

Probe fitted with three level sensors (e.g. NE, NH and NTH)
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 à +60°C
  • Installation location : Zone 0, 1 or 2 GAZ

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
    • This sensor is ATEX certified

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 will

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 à +40°C
  • Installation location : Zone 0, 1 or 2 GAZ

Out of the hydrocarbon, the weight of the floats pulls the magnetic rod towards the bottom of the probe :

  • The NH and NTH 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 OVERFLOW PROBE

ATEX:

  • Category & zone : II 1 G
  • Electrical protection : Ex ia IIC T5 Ga
  • Ambient use temperature : –20°C à +60°C
  • Installation location : Zone 0, 1 or 2 GAZ

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

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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

95 33 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
Please fill in the document here and send it to contact@larco.fr for all enquiries