LEWA Odor Control Unit

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.

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.

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

In-and output monitoring

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.

Increase flow capacity

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).

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.

Inputs	Outputs	Power supply
Two 24 VDC optocoupler units	1 power output for magnetic-driven pump	230 VAC (SPU230)
	1 switched output at 230 VAC or 24 VDC	24VDC (SPU24)
	24 VDC / 20 W component supply (OCU, IOU etc.)

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.

Inputs	Outputs	Power 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

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.

Inputs	Outputs	Power 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

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.

Inputs	Outputs	Power supply
4 Ex digital inputs		24 VDC

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.

Type	CC 7000 wall housing	19‘‘ rack	EExd casing	EExde casing
Dimensions W x H x L [mm]	354 x 237 x 236	483 x 132,5 x 230	depending on size and expansion modules of the control	340,5 x 675,5 x 275