Centrate sampling line
Measured at
Analogue to control system
Signal
Alarm, optional trip
Response
4 steps
Sample to alarm
DEFINITION & OVERVIEW
What is Centrifuge Effluent Monitoring?
A coarse coal centrifuge keeps the coal and lets water and fines drain away as centrate. As long as the screen basket is whole, very little coarse material gets through. When a basket cracks or a bar breaks, coarse coal starts to leave with the centrate instead.
That coal settles in the centrate tank. Over time it builds up until it blocks the pump or the line, and then the problems arrive in a row: launder overflow, water loss and, in the worst case, a plant-wide stoppage. The trouble is that the failure is usually discovered only after one of those consequences, not before.
Our Centrifuge Effluent Monitoring System, System 05 in our instrumentation range, watches the centrate itself. A sampling line takes a small stream off the centrate pipe, a concentration meter reads it continuously, and the signal goes to the central control system. A rising trend sets off an operator alarm, and an interlock trip can be added if you want the system to act on its own. It sits alongside Screen Underflow Anti-Blockage Detection in the plant's process reliability set.
Finds the Fault Early
Watches the centrate for the first sign of coarse carry-over, instead of waiting for a blocked pump or line.
Alarm, With an Optional Trip
An analogue signal feeds the central control system, raising an operator alarm, with an interlock trip available.
Reads the Severity
The worse the carry-over, the faster concentration rises, so a severe failure reaches the alarm sooner.
Parameter | Value |
|---|---|
Monitored Point | Coarse coal centrifuge centrate pipe |
Measurement | Concentration meter in a sampling line |
Normal Condition | Low, steady concentration reading |
Fault Condition | Rising concentration trend against a set threshold |
Output | Analogue signal to the central control system |
Response | Operator alarm, optional interlock trip |
KEY FEATURES
Key Features & Performance Highlights
What this system does for a plant running coarse coal centrifuges.
Detects the Cause, Not Just the Consequence
Most plants find a basket failure when the centrate pump blocks or the launder overflows. Monitoring the centrate catches the cause while the fix is still a planned job.
A Clear Normal and a Clear Fault
With little or no carryover, the concentration reading stays low and steady. A failing basket shows up as a climbing trend, which is easy for an operator to recognize on a trend screen.
Responds in Proportion to the Fault
The more severe the carry-over, the faster concentration rises, and the sooner the alarm point is reached. A small leak gets noticed, and a serious failure gets noticed quickly.
Fits Your Existing Control System
The signal goes straight into the central control system, so there is no separate monitoring screen to watch. Alarms and trends appear where the operator already looks.
WORKING PRINCIPLE
How Centrifuge Effluent Monitoring Works
Four steps, from the centrate pipe to the operator.
Sample
A sampling line is taken off the centrate pipe of the coarse coal centrifuge.
Measure
A concentration meter in the sampling line reads continuously. With little or no coarse carryover, the reading is low and steady.
Detect
If a basket cracks or a bar breaks, coarse material carries over, and the concentration reading climbs in a clear upward trend toward the alarm threshold.
Act
The analogue signal goes into the central control system, which raises an operator alarm and, if fitted, can trip an interlock.
Into the Control Scheme
The control system uses cyclone inlet and pump discharge pressure alongside density, magnetite content and level to keep the dense medium circuit steady.
TECHNICAL SPECIFICATIONS
Centrifuge Effluent Monitoring | System Overview
Item | Detail |
|---|---|
Applies To | Coarse coal centrifuge centrate |
Sampling | Sampling line off the centrate pipe |
Detection | Rising concentration trend against a set alarm threshold |
Output | Analogue signal to the central control system |
Operator Response | Alarm |
Optional Response | Interlock trip |
Working Temperature | -20 to +85 °C |
Supply Voltage | 12-36 V DC |
Output | 4-20 mA, two-wire |
Sensor | Ceramic piezoresistive or diffused silicon |
COMPARISON
Effluent Monitoring vs. Waiting for the Blockage
Centrifuge Effluent Monitoring
Finding It After the Consequence
Applications of Centrifuge Effluent Monitoring
Wherever a coarse coal centrifuge runs and a blocked centrate line would hurt.
Coarse Coal Centrifuge Circuits
Monitors the centrate of the coarse coal centrifuge for screen basket cracks and broken bars.
Centrate Tank and Pump Protection
Stops coarse material from building up to the point where it blocks the pump or the line.
Launder Overflow and Water Loss Prevention
An early alarm keeps centrate flowing to where it should go.
Planned Basket Maintenance
Turns a basket failure from an emergency into a scheduled repair.
Unattended Protection
With the optional interlock trip, the circuit can protect itself on a night shift.
About John Finlay
Process Reliability Systems from John Finlay
Why John Finlay?
4 Steps
Sample to Alarm
Sample, measure, detect, act: a simple chain from the centrate pipe to the operator.
130+
Coal Washery Projects
Completed EPC projects worldwide, including Asia’s largest coking coal washery at 30 MTPA.
EPC
Full Circuit Supply
Supplied as part of a complete instrumentation and automation offering across the coal preparation flowsheet.
IN
India-Based Support
Manufactured at Hefei John Finlay Mining Equipment Co., Ltd. and supported locally in India for installation, commissioning, spares and service.
Centrifuge Effluent Monitoring | Frequently Asked Questions
Common questions from plant engineers worried about centrifuge basket failures.
Coarse coal passes through the crack and leaves with the centrate. It settles in the centrate tank, and as it builds up, it can block the pump or the line, leading to launder overflow, water loss and, in the worst case, a plant-wide stoppage.
A sampling line takes a stream off the centrate pipe, and a concentration meter reads it continuously. Normal operation gives a low, steady reading. Coarse carry-over shows as a clear upward trend against a set alarm threshold.
An analogue signal goes into the central control system, which raises an operator alarm. An interlock trip can be added if you want the system to act automatically.
Yes. The more severe the carry-over, the faster concentration rises, so the alarm point is reached sooner.
Centrate carries abrasive coarse solids when a basket fails, so the meter has to be chosen for that duty. Our engineers confirm the meter type for your centrifuge circuit when the system is specified.Â
The system is designed for the centrate of a coarse coal centrifuge. For help choosing and sizing centrifuges, see our centrifuge selection guide.
Want to catch basket failures before they block the line?
Our engineers can walk you through how to fit effluent monitoring to your centrifuge circuit.
Talk to an ExpertRelated Equipment
Screen Underflow Anti-Blockage Detection (S4)
The sister system that guards against blockage under the screens.
Dense Medium Control System (S1)
The other packaged system in the instrumentation range.
Instrumentation Overview
All John Finlay instruments and control systems in one place.
Centrifuge Selection Guide
Basket capacity and wear life when choosing a coal centrifuge.