Technical background

Flow-optimized measuring tube

Minimal flows usually pose the greatest challenge to flowmeters. These often occur at night, but also if a pipeline network is oversized. The performance of a measuring device during minimal flows can be improved by reducing the nominal diameter. The subsequent increase of velocity results in a better signal strength and thus a better signal-to-noise ratio.

The WATERFLUX measuring tube has a smooth, conical shape with inner reduction to a rectangular profile. This results in a consistent flow profile and thereby reduces or prevents turbulent fluctuations (flow-optimizing effect). The WATERFLUX has been designed to ensure excellent performance both for maximum and minimum flow rates.

No inlets or outlets

Electromagnetic flowmeters usually require certain inlets and outlets to achieve the measuring accuracy specified by the manufacturer. Disturbed flow profiles, such as those that occur after pipe bends or slide valves, considerably affect the measuring result and must be homogenized through long inlets and outlets.

The rectangular cross section of the WATERFLUX increases the flow velocity and optimizes the flow profile within the magnetic field, regardless of where the converter is installed. This means there is no need for straight inlets and outlets and the WATERFLUX can be installed virtually anywhere.

Comparison of flow profiles after pipe bends

The Physikalisch-Technische Bundesanstalt (PTB) in Berlin has studied the behavior of the various cross sections in different flow profiles. It compared the flow profile of a conventional electromagnetic flowmeter (EMF with round cross section) with that of the new WATERFLUX with flow-optimizing cross section after a pipe bend.

Comparison of flow profiles after pipe bends

a) Electromagnetic flowmeters with round cross section

b) Flow profile after a pipe bend

c) WATERFLUX with rectangular cross section

d) Flow profile after a pipe bend

The results of these studies confirm that the WATERFLUX with its flow profile-optimizing cross section offers several advantages: The increased flow rate results an improved signal strength and thus an accurate measurement, even with minimal flows. Errors in the flow profile are reduced by 80 %. The pressure loss resulting from necking is negligible.

Maximum measuring accuracy

Maximum measuring accuracy

The high measuring accuracy (±0.2% of measurement ±0.5mm/s) together with excellent repeatability means that the flowmeter can also be used in custody transfer in accordance with OIML R-49 and MI-001. The zero point stability of the WATERFLUX is considerably better than simple process measuring equipment. As a result, the instrument can measure even minimal flow rates bidirectionally with a high accuracy and can therefore be used for detecting leaks and measuring leak flow volumes.

Low pressure loss

Generally speaking electromagnetic measuring devices have no moving parts in the measuring tube, which means there is little pressure loss. The patented shape of the WATERFLUX's measuring tube has also been specially designed to ensure little pressure loss: The OIML directive allows a pressure loss of 630mbar for a flow rate of 8 m/s in water measurements. The WATERFLUX value is considerably lower than this at 500 mbar. The WATERFLUX's pressure loss at the normal flow rate for water networks of approx. 1 m/s is < 10 mbar.

Low pressure loss
Rilsan® polymer coating

Rilsan® polymer coating

Rilsan polyamide 11 is a soft, powdery plastic, based on vegetable caster oil. It can be used to manufacture high-quality coatings which offer effective and lasting protection against the growth of bacteria. The Rilsan lining on the WATERFLUX measuring tube is extremely resistant to corrosion, ageing and abrasion. WATERFLUX is, therefore, suitable for use with foodstuffs in accordance with KTW, DVGW and ACS and is thus approved for drinking water.

Multiple power concept for any location

The battery-powered WATERFLUX 3070 is ideal for remote locations in the water industry where no mains power is available. KROHNE has developed a special sensor construction requiring very low power for the longest battery lifetime. As standard the IFC 070 signal converter has an internal battery pack with a dual D lithium cell. For an extended battery lifetime an external battery pack, the PowerBlock, with a lithium dual DD cell can be connected to the converter.

The meter reading is saved internally, which ensures that there is no loss of data when changing the batteries.

Thanks to the rectangular cross section, the magnetic coils are relatively close together compared to round cross sections and thus require less energy to generate an adequately strong and homogenous magnetic field.

Cross section comparison

Cross section comparison: Structure of an EMF with round cross section, structure of the WATERFLUX

1= induced voltage (proportional to flow velocity)

2= Electrodes

3= Magnetic field

4= Field coil

A magnetic core with a small round coil has been used instead of saddle coils. This round coil has very short turns and, therefore, offers less ohmic resistance at the same magnetic force (see fig.). The resulting low power consumption and the special batteries developed according to the industry standard (in terms of stray currents and temperature effects) provide a durable, independent power supply. The special geometric layout of the magnetic circuit also prevents idle power from being generated along with the magnetic field.

The battery life depends on the number of integrated batteries as well as the set measuring frequency (see diagram). At the default measuring frequency of 1/15 Hz and a temperature of approx. 25°C the life cycle with

  • 2 integrated batteries is: 10 years
  • external battery pack is: 15 years

Thanks to the low power consumption, batteries in the WATERFLUX last up to 5 times longer than in  similar devices.

For locations where mains power is available, but water companies demand a power backup to ensure continuous measurements, the WATERFLUX 3070 can be equipped with an external IP68 FlexPower unit. The input power for the KROHNE FlexPower can be supplied by connecting an 110...230 V AC mains supply source. Should the mains power supply fail, an internal battery will take over the power supply to the IFC 070 signal converter as a backup. To save energy, the meter will automatically switch over to a low-power-consuming battery backup mode.

Solar or wind power can provide an alternative to battery power for locations where no mains power is available. There is a growing market demand for green power sources like wind and/or solar energy. For this purpose the FlexPower unit is delivered with a special power cable for connection to a 10...30 V DC power supply.

Flow, pressure and temperature measurement with just one device

Maintaining the water balance, reducing pumping costs, pressure monitoring and district zoning (DMA) are Focus areas for water companies in drinking water Distribution networks. Pressure and flow data give important input for monitoring and operating networks. Managing pressure levels is required for efficient transport and delivery of potable water. A large pressure drop is an indicator for leakage.

Safety of drinking water is a key priority for water companies. Temperature control is required because high temperatures may pose a risk to public health and flushing of networks is needed. When potable water has reached a critical value, the WATERFLUX 3070 sounds an alarm.

WATERFLUX 3070 is the first all-in-one water meter that measures flow, pressure and temperature simultaneously with just one instrument. The WATERFLUX 3000 sensor is equipped with an integrated pressure and temperature sensor.

  • Flow, pressure and temperature measurement values can be read on the IFC 070 display and can be read out via Modbus RTU
  • An alarm can be generated via the status output or via Modbus when critical limits for pressure and/or temperature are exceeded ultimate Efficiency

Direct subsurface installation

Thanks to its reliability, maintenance-free operation and its robust construction the flow sensor can also be buried underground.

Burying the sensor directly under the ground has a number of advantages. It can be a major cost saving because it eliminates the need for a measurement chamber. With no moving parts to wear out or other parts that can break down, there is little to no need for meter maintenance. Verification options on site ensure the integrity of the meter. All sizes can be buried. To protect the flow sensor a special subsoil coating
can be ordered. The remote sensor version has an IP68 stainless steel connection box.

Data communication options

Our equipment needs to support customer business processes like zoning for water balance (DMA), water abstraction, pressure management, and revenue collection. For this water companies need more measurement data, smart data, accurate data and real-time data.

WATERFLUX 3070 provides important data like sum, forward and reverse flows, and flow rates at critical measurement points. With the integrated pressure and temperature sensor the actual values for pressure and temperature become available. It also provides meter and battery status information.

The display forms the main source of data for meters that are used for billing and are subject to custody transfer (OIML R49, MI-001). Measurement and meter status data can be given out either via 2 pulse and 2 status outputs or via a Modbus RTU RS 485. Simple data communication requires a simple interface between the WATERFLUX 3070 and a wide range of communication equipment and systems in use in the market.

Modbus communication

Battery powerFlexPower (mains power)
  • 2 pulse + 2 status outputs
  • Optional low power Modbus communication for connection to GSM/GPRS module
  • 2 pulse + 2 status outputs
  • High power Modbus communication for connection to e.g. PLC 

WATERFLUX 3070 can communicate by RS485 using the Modbus RTU protocol. An add-on board for the Modbus module is integrated in the IP68 converter housing. Modbus has been selected because it is a mature, versatile and accepted protocol and can be easily integrated into other communication systems. It forms a standard solution to disclose all data available from the IFC 070 signal converter.

WATERFLUX 3070 offers two RS 485 Modbus RTU interface options: a low (battery) power and a high (mains) power Modbus option. The low power (non-isolated) Modbus version is unique in the market and can be used for data communication between a battery-powered WATERFLUX 3070 version and a battery-powered data logger GPRS module. In the case of the WATERFLUX 3070 with FlexPower, the mains powered water meter, the high power (isolated) Modbus option can be ordered for data communication to process automation systems (SCADA, DCS, PLC).

GSM/GPRS delivers information from anywhere in the world

Bulk water meters are often installed over a wide area and at measuring points in remote areas or water chambers under the ground or difficult-to-reach transitional points. The unique low-powered battery Modbus option has a dedicated chipset for a long lifetime and can be connected to a battery-powered GSM/GPRS data logger unit for a complete remote solution.

Via its outputs the WATERFLUX 3070 can be connected to a wide range of data logger and remote communication equipment from various brands that support pulses and/or Modbus. It has already been tested with the following preselected vendors:

  • Datawatt
  • Jiaxing HgDao
  • Lacroix Sofrel
  • Metasphere
  • Primayer

Web-based data hosting

Through a dedicated web site, data can be viewed or exported for further analysis. The advantages are: a fully secured data base and confidential access to data, no more constraints to handle a SCADA and data presentation can be customised by the end user. Additionally, PC-based data hosting can be used.

A wide range of collected data are available, e.g.:

  • Trend curves with statistics and printing
  • List of data (counters, flow, daily/weekly/monthly reports, measurements, alarms, etc.)
  • Data exported in Excel
  • Automatic alarms to be sent to a dedicated e-mail address
  • Data can be sent to a dedicated FTP server

Long-term reliability and simplified installation

In a world where water is becoming scarce, potable water is a precious resource. Flow measurements of potable water need to be very accurate as they form the basis for efficient water network management and for the billing of water consumption.

Every single flowmeter is standard wet calibrated before leaving the factory. As an option verification to custody transfer standards (OIML R49, MI-001) can also be ordered. KROHNE operates a large number of accurate calibration facilities including the world’s most precise volumetric calibration rig for flowmeters.

Thanks to its unobstructed measuring section, the WATERFLUX sensor is far superior to conventional mechanical water meters, in terms of pressure loss and long-term stability. The WATERFLUX 3070 performs automatic self-tests including an of integrity check of hardware and software and a calculation of the remaining battery lifetime. If required, warnings and error messages are available on the display, via the status outputs or via Modbus.

The OPTICHECK provides an inline health check to make sure that installed electromagnetic flowmeters are performing within specification. When the tool is connected on site, it gathers measuring data to ensure that the flowmeter is performing within 1% of its factory calibration. A hard copy verification report can
be printed for every flowmeter. Contact KROHNE for more information or for an onsite service visit.

WATERFLUX simplifies installation and minimises maintenance

Water meters are distributed over a widespread area and are often in difficult-to-reach locations ranging from:

  • Remote sites of water wells
  • Long-distance distribution networks
  • Measurement chambers under busy roads
  • Small, narrow or flooded measurement chambers
  • Basements of buildings

The WATERFLUX 3070 offers many features and benefits to simplify engineering in various conditions:

  • Multiple power concept, providing a power solution for any location
  • Diameter range on batteries from DN25 up to DN600
  • Compact and remote converter housing
  • Reduced straight lengths (0D inlet, 0D outlet) for locations with minimal space
  • Subsoil installation where no measurement pit is required

To control costs easy installation and minimal visits to site are prerequisite for water companies. To simplify the installation on site the WATERFLUX 3070 offers:

  • Battery power option, meaning no electrical wiring on site
  • Plug & play MIL connectors further reduce the need for wiring on site
  • A standard reference electrode, making grounding rings obsolete
  • Compact and low weight design
  • Installation without filters or strainers

To reduce site visits, the WATERFLUX 3070 has a:

  • Robust construction with no obstructions in the flow for a long-term reliability
  • Tamper-proof design
  • Long-lasting batteries
  • Range of communication interfaces to reduce the need for manual collection of data

Installation in measurement chambers

Water meters are used for monitoring and control purposes in the water distribution networks running from the water production plant down to the customer. The meters are often installed in measurement chambers under ground.

The installation of a WATERFLUX 3070 has some major benefits compared to a mechanical meter because it does not need upstream and downstream piping but also no ancillary equipment like strainers, filters or isolation valves with a bypass.

All that is required in the measurement chamber is the sensor itself leading to substantial lower installation costs. A (compact or remote) Signal converter and an optional data logger/GPRS unit can be installed either in the measurement chamber or above the ground. Above the ground the remote Signal converter and datalogger/GPRS unit are usually placed on a pillar or in an electrical cabinet.

With its maintenance-free design also substantial reductions in maintenance costs can be realised. There is no need for removing the sensor from the line for a recalibration. The OPTICHECK is available for verifying the integrity of the flow sensor, transmitter and transmitter cable.