Non-invasive, portable and explosion-proof clamp-on ultrasonic flowmeters are proving to be an essential tool for ensuring the safe and efficient operation of chemical production plants.
These plants form a complex system of material and energy flows, with everything from raw materials to end products flowing through a network of pipelines and pumps. This means that flow measurements are crucial for ensuring that everything runs as smoothly as possible.
Traditional wetted measuring systems are subject to constant wear and tear, which can lead to a loss of accuracy or even complete failure. There are also often areas where flow rates need to be measured but no permanent measuring device is installed. This is where clamp-on ultrasonic flowmeters offer an accurate and reliable alternative.
Using the proven transit-time correlation technique, special Lamb and shear wave transducers are simply clamped to the outside of the pipe. For measurement, two ultrasonic pulses are sent through the medium – one in the direction of flow and a second one against it. Each transducer is alternately working as an emitter and a receiver, and the transit-time of the ultrasonic signal propagating with the flow direction is shorter than the transit-time of the signal propagating against the flow direction. A transit-time difference can therefore be measured, allowing the determination of the average flow velocity based on the propagation path of the ultrasonic signals.
There is no need to cut the pipe, and no need for plant process interruption to carry out installation, which is of particular benefit to facilities where pipes can’t easily be depressurised.
Non-invasive flow measurement in potentially explosive zones –
Due to explosion protection reasons, hydrocarbons must not exceed a certain flow rate when transported through pipelines, in order to prevent potentially dangerous electrostatic charges. For the same reason, the possibility of pumps running dry has to be prevented. These pumps are therefore fitted with limit switches that cut off the pumping process if the defined limit values are exceeded or not reached. Ideally, this safety function is set up with the help of a flow measurement.
This is exactly why system engineers at a leading international provider of solutions for high-quality hydrocarbon products were looking for a portable clamp-on ultrasonic system for non-invasive flow measurement. They also needed a flowmeter approved for use in potentially explosive areas.
FLEXIM’s portable energy flowmeter specially designed for measurement in hazardous areas was chosen for the task, along with a pair of CDM clamp-on ultrasonic transducers that cover practically all liquid applications with a pipe diameter range of 50 mm to 3400 mm. The transmitter can also measure gases and liquid-based thermal energy flows, and the company has the option of retrofitting it with gas transducers if required.
Rapid set-up of high-precision flow measurement –
The portable flowmeter is now working at full capacity to check and readjust the protective functions on the pumps. It is in use almost every day, and is also used to check existing measuring devices.
The users greatly appreciate the practical functionality of the measuring system, which allows for high-precision flow measurement to be set up quickly. The system allows the user to parameterise pipe and media data, mount transducers accordingly and deliver reliable measuring results in less than five minutes.
Due to this positive experience, the site is now planning to fit stationary flow measuring points with clamp-on ultrasonic technology from FLEXIM.
For more detailed information on the benefits of non-invasive ultrasonic flow measurement in the petrochemical industry, contact Simon Millington – www.flexim.co.uk | firstname.lastname@example.org | +44 (0)1606 781 420
By FLEXIM Instruments UK Ltd