Ductus is a time of flight system designed for highly accurate flow measurement in water distribution networks and hydropower plants. 

Flow monitoring is very often mandatory in the area of water supply and industry. Quite frequently, the pipe systems are complex and contain valves and pumps. Due to the patented velocity profile compensation of GWF's Ductus, no flow straighteners or on-site calibration are required. The unique digital signal processing allows the detection of even the smallest time differences, i.e. even the smallest amounts are determined accurately.

Ductus is equipped with an integrated web server running a WebUI. You can display and manage the WebUI using the standard web browser of your smartphone, tablet, PC or notebook. There is no need for any additional software or App. Parameter setting and data visualization has never been so easy.

In the unlikely event that a transducer should fail, Ductus can be programmed to automatically compensate for the loss in path information with little reduced accuracy. Additionally, the operator is advised that an alarm is present. 

The feedthrough transducer housings are separated from the transducers themselves and are designed to allow removal of the entire sensor for repair, replacement, or cleaning without the need to dewater the pipe or shut down the process.

Space constraints and application configurations lead to complex flows in pipes which contain elbows, tees or other disturbing and non-uniform elements. This leads to difficulties in installing flowmeters at an optimum location; which is defined by a minimum distance upstream or downstream of known disturbances at which a fully developed velocity profile is present. For traditional flowmeters, significant errors may be caused by these adverse installation conditions.

In contrast to conventional systems, Ductus provides detailed information on the flow velocity profile. An accurate measurement of the flow rate can be achieved by replicating the flow velocity profile across the pipe. Accuracy is maximized using predetermined conduit configuration parameters and correction factors, which incorporate the specific local installation conditions.

Conventional flowmeters are also sensitive to velocity profiles with a large rotational component (swirl). Swirl can be caused by pumps or multiple out-of-plane changes in flow direction. It is present to some extent in almost every application and can generate significant transverse velocity components; and it takes a long distance to dissipate. If the swirl is not accounted for, it can cause significant errors. Ductus can quantify and correct these disrupting factors without difficulty. The Ductus system keeps its measurement accuracy even when asymmetric profiles and swirls are present in the flow.

Wetted sensors arranged in five parallel planes

The Ductus system is composed of a wall-mounted transmitter and several sensor options. For non-intrusive measurement, clamp-on transducers are available. If the pipe can be dewatered for installation, feedthrough or internally mounted sensors are suitable options. For multi-path systems, a separate housing to connect up to 20 transducers is available.

Standard transmitter

Multi-path extension housing

The Ductus transmitter incorporates all the required algorithms and software to ensure measurement accuracy and repeatability. The IP66 (NEMA 4X) compact housing features a 4 x 20 alphanumeric LCD display and a 4 button keypad. 

All configuration data as well as measured and calculated data are stored inside a 16 GB MicroSD card. The transmitter controls the measurements, calculates the flow rate and provides freely programmable current outputs, status alarms, frequency outputs and totalizer readings. 

The Ductus standard transmitter accommodates 2 acoustic paths. For systems with up to 10 measurement paths, an extension housing is available

CO-L, clamp-on sensor 200 kHz

CO-S, clamp-on sensor 1 MHz

When combining the Ductus with clamp-on transducers, the flow measurement becomes non-intrusive. The transducers are installed with little technical effort and without process interruption on the pipeline. This non-invasive measurement method is suitable for various media such as wastewater, salt water and glycol.

Clamp-on transducers require no modification of the conduit or plant shutdown. Once the CO-L sensors have been installed, they can easily be removed from the mounting system, for example to renew the coupling paste. This prevents a shift of the installation position.

FT-S and FT-L feedthrough sensors

Internal mount sensor TD-IM

Depending on your individual requirements, several options of feedthrough sensors are available. For the sensor type FT-S the pipe only needs to be dewatered for the initial installation. Removal of these sensors for cleaning, repair or replacement is possible without process interruption.

If the pipe is accessible only from the inside, internally mounted sensors are a suitable option.