Model 9620 determines solids concentration in slurries using ultrasound non contacting sensors.

Application: Measurement of density / concentration of non-dissolved solids in slurries.
Industries: all

Instrumentation: Rhosonics Model 9620 + UFTC and UFTS- series probes.

Introduction

The need for inline analysis of density or total suspended solids concentration in slurries in various processes has increased in recent years, due to safety regulations and the need for reducing the costs of laboratory analyses. The concentration analyzer, using the propagation characteristics of sound waves in liquids, enables an easy, reliable and maintenance-free analysis of slurries.

Principle of operation

Ultrasonic inline analysis as it is being deployed by Rhosonics utilizes the range of frequencies from approximately 20 KHz to over 10 MHz. Sound pulses are normally generated and received by piezoelectric transducers that have been acoustically coupled to the liquid to be analyzed.
In many slurry applications a single transducer, recessed in the pipe wall or forming an integral part of a pipe section, serves as both transmitter and receiver (pulse/echo mode). For some applications involving large pipe sizes or very dense slurries, two separate transmitting and receiving transducers on opposite sides of the pipe are used (Through transmission mode).

The sound waves are launched by exciting the transducer with a precisely defined pulse having a specific frequency spectrum. The sound waves travel through the flowing liquid, either reflecting off the opposite side of the pipe to return to its point of origin (pulse/echo), or are being received by another transducer, usually located at the opposite side of the pipe wall. The received signal is then amplified and analyzed the Rhosonics Model 9620, employing advanced signal processing.
As the sound waves are traveling through the slurry, emulsion or suspension, the sound waves are interacting with particles within the liquid, such as non-dissolved particles, either suspended or emulsified.

During the propagation through the liquid, sound waves are both attenuated by scattering (reflection of sound) as well as by absorption. The Rhosonics Model 9620 precisely measures the ratio between transmitted and received signal. As this ratio is directly proportional to the concentration of the suspended solids, Model 9620 provides a direct reading in terms of percent solids and density of the slurry.

Inline sensors

Because the flow of the slurry should preferably not disturbed, Rhosonics has developed a range of sensors, fulfilling these demands. Figure 4 is showing a flow-through sensor section, with a 3”-150LBS flanges and 3 inch bore size, with sensors installed.

This flow-through system employs two sensors, which are mounted diagonally. They are made flush with the pipe wall, thus avoiding build-up of material on the sensors. As previously explained, one transducer is acting as transmitter of pulsed ultrasonic sound waves, the other as receiver.
This flow section is available in pipe sizes of 3” up to 14” in diameter.

Controller

For all slurry applications, the Model 9620 is serves as controller and readout of concentration. The Model 9620 has all electronics on board to transmit and receive the ultrasonic signals and convert it to a concentration signal. Available in bench mount version, rack mount or in weatherproof housing, the Model 9620 features both analog and digital outputs, allowing continuous monitoring of the concentration at all times.
Consult your sales representative to discuss the most ideal controller version and sensor type for your specific application.

Payback of the analyzer

As an illustration of cost-savings due to accurate analysis, consider a plant that installs a Rhosonics sensor in a pipeline, thereby avoiding downtime due to clogging with 2 days per year.
Suppose this plant produces 125 tons of product per day at $50 per ton would save:
0,55% of one year production is 0,55% of 125 x 365 x $50 = $ 12 375 per year.
The installed inline sensor also reduces the amount of (hot) water, leading to 5% annual energy saving. On a daily basis this plant consumes $5 of energy per ton produced, and thus saves:
 5% of 125 x 365 x $5 = $ 11 406 per year.
With this amount of savings, the payback time of the analyzer is less than seven months. Consequently, annual savings are as much as $ 23 781 per year.

Conclusions

The Rhosonics Model 9620 Concentration Analyzer is the most accurate instrument for inline analysis of slurries. It is the only instrument that can be used over the entire working range of commercial concentrations with remarkable accuracy. In addition, it has no moving parts and its accuracy is not degraded by fouling, which is a common problem with coriolis meters and differential pressure meters.
In addition, the UltraSmart system makes the analysis highly reliable, all together resulting in higher profitability in any plant where the concentration of a slurry must be carefully measured and/or controlled.

Meauring range slurry: 0~5%; 0~10%; 0~20%; 0~40%;
Typical overall accuracy: 0.15% of range, minimum 3% of reading