Separator Cyclone Monitoring

Phil Black - PII Editor 29/06/2009

211 1 minute read

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This application looks at monitoring the downstream pressure of abrasive slurry and liquids in cyclones with process pressure sensors.

Also used successfully in other process for pressure measurement on abrasive, sticky andor charged fluids with suspended solids.

Main Application Details
Level & temperature measurement through hydrostactic pressure sensors
Product:    Water, sand, grit and clay slurries.
Vessel:    Cyclone and pipework
Temperature:    Ambient
Pressure:    1 – 2 bar

Application

In a quarry or process where raw materials are ‘washed out’ using water to be recovered and then reprocessed, a cyclone is often used in order to separate out the useful materials.
To prevent blockages in the cyclone (often caused by to variations in the concentration in the raw materials in suspension) it is important to monitor the pressure downstream. If this pressure falls, the control system can decrease the raw material flow, via an inverter drive to a pump or a valve positioner for example, to allow it to clear. The wear on all process parts this area is very high, as is the chance of blockage for any recessed parts.

Solution

A pressure sensor with a 1″ totally flush ceramic cell is mounted in the wall of the pipe, just downstream of the cyclone. The pressure exerted on the membrane is proportional to the efficiency of the cyclone. Any pressure change means the flow can be regulated to ensure optimum efficiency. Ultra high purity ceramic is used as a diaphragm material because it is a highly durable, abrasion and overload resistant, delivering high accuracy and linearity over long periods.Polymer seals are protected by special design.

Technology

The pressure applied minutely deflects a ceramic sensor diaphragm (as little as 10 microns) This deflection is measured using a special dry capacitor circuit (with a self-monitoring system for diaphragm integrity) and then converted to an output signal for the transmitter.

Benefits of using process pressure sensors in this type of application:

Flush cell, no risk of clogging, direct measurement
High abrasion resistance (polymer seal is protected behind cell face)
High sensitivity of the cell (<0,1 %) for real time process control.