Odorcontrols

LEWA Odor Control Unit

For more than 40 years, LEWA develops and designs systems and units for the odorization of gases. In a odorization process, a odorous gas is metered to odorless and potentially hazardous gases. Thus, leakage of gases can be detected as early as possible and accidents are avoided. To ensure that the correct amount of the odorant is metered, LEWA has developed a modular control odor control unit.

LEWA Odor Control Unit
Monitoring and control of odor concentration.

LEWA offers a complete system for the fully automatic monitoring and control of odorizing systems that is also suitable for easy retrofitting of existing LEWA systems or those of other manufacturers. All the important operating data is available as output signals for recording and for remote transmission.

Thanks to the continuous monitoring of the odorizing systems, this control allows the weekly inspections of the odorizing systems required by DVGW (German Technical and Scientific Association for Gas and Water) to be omitted or done at longer intervals. That reduces costs while still maintaining total reliability. Another advantage is the system's easy handling for operating personnel.

Setting the desired odorant concentration is done in digital steps of 0.1 μl/Nm3 on the controller. A target/actual value comparison is available at all times. If the value deviates, a correction is made completely automatically in a closed control loop. An error message is output for deviations caused by external influences. Time-consuming configuration at the concentration on the stroke adjustment of the metering pump is completely eliminated. In addition to the time saved, odorant consumption is also optimized due to the precise setting and the automatic monitoring and readjustment. This significantly lowers ongoing operating costs.

LEWA odorization system for gas odorization

Modular design of the odor control unit

The OCU control unit is a modular unit with 19" expansion cards and can be provided either in a 19" rack or in IP65 housing for wall mounting. The control consists of one or two SPU power supply units and power pack units, an OCU control unit and, depending on requirements, additional expansion assemblies.

Odor control unit OCU

The Odor Control Unit (OCU) is the CPU and the base unit for controlling one or two magnetic-driven or motor-driven pump(s). The connection to the expansion modules is possible either via digital outputs (to SPU) or via BUS. All settings can be made with a keyboard with nine keys using a dialogguided system. Multiple dialog languages are selectable.

All data is securely saved to a FRAM in case of power failure. All malfunctions are printed in plain text on the display (8 x 20 characters). The error memory can save more than 200 messages with date and time.

With the OCU, up to two metering pumps alternately (e. g. for summer/winter operation) or together (to increase flow capacity) can be controlled. Also, control of magnetic-driven or motordriven metering pumps is possible. The OCU regulates and monitors a preselected odorant concentration in μl/Nm³ or mg/Nm³. The unit of measurement for gas flows can be selected (Nm³, m³, l, kg).

All analog input and output signals are monitored. There is a digital "Stop odorization" input in order to stop odorization, for example when refilling. Furthermore, digital inputs are available for up to two pressure switches to monitor the diaphragm(s) of the metering pump(s). The connection to a central computer can be done using a serial interface RS485 and the MODBUS RTU protocol.

The OCU features connection options for:

  • A KMM actual-value sensor (flow meter) or an actual-value sensor with pulse output
  • Up to three digital or analog gas meters, each with its own scaling
  • A pressure transducer in the gas line to convert gas meter 1 into Nm³
  • One or two gas chromatograph(s) for recording odorant concentration(s)
  • Solenoid valves in the metering lines
  • Solenoid valve in the filling line to a large tank
Odorcontrols

InputsOutputsInterfacesPower supply
10 digital inputs 24 VDC (optocoupler)2 relays: 1 isolated changeover contact, 1 isolated normally open contact1 RS23224 VDC
5 analog inputs 0/4-20 mA (12 bits)4 active optocoupler outputs (24 VDC / 20 mA)2 RS485
2 analog outputs (0/4-20 mA)

Odor control unit SPU

The odor control unit SPU is the power supply unit and the magnetic-driven pump power pack unit for all MAH – MLM40 magnetic-driven pumps. With the SPU, a solenoid valve in the pressure line can be regulated via two 24 VDC optocoupler units.

[Translate to English:]

InputsOutputsPower supply
Two 24 VDC optocoupler units1 power output for magnetic-driven pump230 VAC (SPU230)
1 switched output at 230 VAC or 24 VDC24VDC (SPU24)
24 VDC / 20 W component supply (OCU, IOU etc.)

Odorcontrols  spu

Expansion module IOU

The expansion module IOU is a card for additionally required inputs and outputs and special functions (e. g. filling logic). The card has its own front panel with LEDs and is normally provided with power via the SPU.

InputsOutputsPower supply
4 digital inputs 24 VDC (optocoupler)4 relays (4 isolated normally open contacts)24 VDC
4 analog inputs 0/4-20 mA (12 bits)2 analog outputs 0/4-20 mA (12 bits)
1 isolated optocoupler output (max. 24 VDC / 20 mA)
2 active optocoupler outputs 24 VDC / 20 mA

Odorcontrols iou

Expansion module SIOU

Expansion card SIOU is for activating the feedback control. It features additionally required inputs and outputs and special functions (e.g. filling logic), but – unlike the IOU – the card is installed behind the OCU and does not have its own front panel. The expansion module is normally provided with power via the SPU.

InputsOutputsPower supply
4 digital inputs 24 VDC (optocoupler)4 relays (4 isolated normally open contacts)24 VDC
4 analog inputs 0/4-20 mA (12 bits)2 analog outputs 0/4-20 mA (12 bits)
1 isolated optocoupler output (max. 24 VDC / 20 mA)
2 active optocoupler outputs 24 VDC / 20 mA

Odorcontrols siou

Expansion module EXU

The expansion card EXU provides digital EX inputs (e. g. KMM, float switch, etc.). The card has its own front panel with LEDs and is normally provided with power via the SPU.

InputsOutputsPower supply
4 Ex digital inputs24 VDC

Odorcontrols exu

Odor control unit housing

The odor control units are available in a CC 7000 wall housing with integrated motherboard and standardly 13 holes for screwed cable connections or in a 19" rack with built-in motherboard. Also, variants in explosion-proof housings are available.

TypeCC 7000 wall housing19‘‘ rackEExd casingEExde casing
Dimensions W x H x L [mm]354 x 237 x 236483 x 132,5 x 230depending on size and expansion modules of the control340,5 x 675,5 x 275

Odorcontrols

Downloads

  • LEWA Odoriersysteme (DE)
    LEWA Odoriersysteme für Erd,- Bio und Flüssiggas. Individuelle Konzepte und Auslegungen. | pdf | 19.09.2017
  • LEWA odorizing systems (EN)
    LEWA odorizing systems for natural gas, biogas and liquefied gas. Individual concepts and dimensions. | pdf | 19.09.2017

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