Ultrasonic level transmitter is optimised for open channel flow measurement
21 November 2007
Emerson Process Management is offering a new version of its Mobrey MSP900 ultrasonic level transmitter, optimised for use in open channel flow measurement. The new MSP900FH, which features a pre-wired remote temperature sensor, is ideal for helping water and industrial processing sites comply with MCERTS legislation.
Many effluent treatment sites in the UK are currently reviewing their open channel flow measurement systems in order to meet MCERTS regulations which are now extended to apply to industrial processors as well as water companies. Typically, such systems consist of an ultrasonic level transmitter mounted over a flume or weir.
Used in the open air, conventional ultrasonic level transmitters are prone to suffer from inaccuracies caused by ‘solar gain’ when the sun shines directly on them. The Mobrey MSP900FH transmitter has been designed to overcome this problem by using a remote temperature sensor wired directly into the transmitter. Measuring just 10mm diameter x 25mm length, the compact sensor can easily be located in an appropriately shady spot between the liquid surface and the transmitter. In this way, the system ensures that the air temperature measurement used in the speed of sound calculation is truly representative.
The sensor is hard-wired into the transmitter with a two-metre cable, so there is no additional cabling or set up required, and only a single connection to the controller, thus keeping installation costs to a minimum.
“We have made this development as a direct response to what our customers were telling us,” explains Emerson water industry expert Peter Ward. “It is a neat, functional answer to a common problem. In extended field trials at a customer site MSP900FH consistently out-performed competitive conventional designs.”
The Mobrey MSP900FH is 24V DC loop powered, supplied in a waterproof housing sealed to IP68. It has both analogue 4-20mA communications and digital HART options built-in, and can be used stand-alone, or as part of a site-wide measurement, control and data acquisition system.
Mobrey MSP level transmitters are part of the broad range of intelligent, digital field devices that power the PlantWeb® digital plant architecture to improve plant efficiency by 2% and more through delivering asset optimisation, process automation, and management execution.
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