Dense Medium Control System (System 01)
A complete instrument set and control scheme for the dense medium circuit density, magnetite content, level and pressure, all non-radioactive, supplied as instruments, as a packaged system, or as a full design-and-implementation scope.
5
Instruments in Set
±0.002 g/cm³
Density Accuracy
±0.5%
Magnetite Accuracy
No AERB Licensing
Regulatory Burden
DEFINITION & OVERVIEW
What is the Dense Medium Control System?
The Dense Medium Control System is a complete instrument set and control scheme for the dense medium circuit. The instruments that set the cut-point and hold it there. Suspension density, magnetite content, level and pressure are the four variables that actually determine separation performance, and this system measures every one of them continuously, feeding a control scheme and panel that closes the loop rather than leaving it to periodic manual checks.
Five real instruments make up the standard system: a differential pressure density meter for continuous suspension density on the correct and dilute medium lines; a magnetic content meter for magnetite concentration, the basis of medium balance; a differential pressure level transmitter for correct and dilute medium sump levels; pressure transmitters for cyclone inlet and pump discharge pressure; and the control scheme and panel itself, handling the density loop, medium make-up logic, and operator interface.
Every measurement in this system is non-radioactive; the density meter uses differential pressure, not a nucleonic source, which means the whole system avoids AERB licensing entirely, a genuine regulatory and administrative simplification for any washery in India specifying dense medium instrumentation from scratch.
Complete Cut-Point Instrumentation
Density, magnetite content, level and pressure for every variable that determines separation performance, measured continuously.
Non-Radioactive Throughout
The differential pressure density meter at the core of this system avoids AERB licensing entirely; there is no radioactive source anywhere in the set.
Supplied However You Need It
Available as individual instruments, a packaged system, or a full design-and-implementation scope not a forced all-or-nothing purchase.
Parameter | Value |
|---|---|
Density Meter Range | 0 – 4 g/cm³, ±0.002 g/cm³ accuracy |
Magnetic Content Meter Range | 0 – 1000 / 0 – 2000 g/L, ±0.5% accuracy |
Level Transmitter Accuracy | ±0.1% digital, ±0.25% analogue |
Pressure Transmitter Range | −0.1 MPa to 100 MPa, ±0.2% FS typical |
Common Platform | Shared electronics and spares across all transmitters |
Radioactive Source | None differential pressure and electromagnetic induction principles only |
KEY FEATURES
Key Features & Performance Highlights
Five real instruments from John Finlay's own instrumentation documentation, each with its own dedicated page linked below.
Differential Pressure Density Meter
Continuous suspension density on the correct medium and dilute medium lines, ±0.002 g/cm³ accuracy, no radioactive source, no AERB licensing.
Magnetic Content Meter
Measures magnetite concentration in the suspension by electromagnetic induction, the basis of medium balance across a 0-1000 or 0-2000 g/L range at ±0.5% accuracy, via a full-bore flanged spool with no insertion element in the slurry stream.
DP Level & Pressure Transmitters
A differential pressure level transmitter tracks correct and dilute medium sump levels; pressure transmitters monitor cyclone inlet and pump discharge pressure; both share a common electronics platform and spares holding one calibration procedure and one set of spares across the plant.
Control Scheme and Panel
Ties all four measurements density, magnetite concentration, level and pressure into the density loop, medium make-up logic, and operator interface, closing the loop rather than leaving cut-point control to periodic manual checks.
WORKING PRINCIPLE
How the Dense Medium Control System Works
Five instruments feed one control scheme, closing the loop on cut-point control rather than leaving it to periodic manual measurement.
Suspension Density Measurement
The differential pressure density meter continuously measures suspension density on the correct medium and dilute medium lines.
Magnetite Concentration Measurement
The magnetic content meter measures magnetite concentration by electromagnetic induction, the basis of medium balance calculations.
Sump Level Monitoring
The differential pressure level transmitter tracks correct medium and dilute medium sump levels continuously.
Circuit Pressure Monitoring
Pressure transmitters monitor cyclone inlet pressure and pump discharge pressure, both sharing a common electronics platform.
Closed-Loop Control
The control scheme and panel combine all four measurements into the density loop, medium make-up logic, and operator interface, closing the loop rather than relying on periodic manual sampling.
TECHNICAL SPECIFICATIONS
Dense Medium Control System | Full Specification
Real specifications for all five instruments in the system, sourced directly from John Finlay's instrumentation documentation.
Parameter | Key Spec | Function |
|---|---|---|
Differential Pressure Density Meter | 0-4 g/cm³, ±0.002 g/cm³, 0.2 s response | Correct & dilute medium density |
Magnetic Content Meter | 0-1000/2000 g/L, ±0.5%, DN100-200 | Magnetite concentration, medium balance |
DP Level Transmitter | ±0.1% digital, ±0.25% analogue | Correct & dilute medium sump levels |
Pressure Transmitters | −0.1 to 100 MPa, ±0.2% FS typical | Cyclone inlet, pump discharge pressure |
Control Scheme & Panel | Shared electronics, common spares | Density loop, medium make-up, operator interface |
COMPARISON
Instrumented Dense Medium Control vs. Manual Circuit Monitoring
With Dense Medium Control System
Without Direct Blockage Detection (Typical)
Applications of the Dense Medium Control System
This system is specified wherever dense medium cut-point control needs to be measured and closed-loop controlled, not periodically checked and manually adjusted.
Dense Medium Cyclone Circuit Control
The core application is continuous density, magnetite, level and pressure measurement feeding cut-point control on the dense medium cyclone circuit.
Medium Balance Management
Magnetite concentration measurement is the basis for medium balance calculations and make-up decisions.
Retrofitting Away from Radioactive Density Gauges
A complete, non-radioactive replacement path for washeries looking to eliminate AERB licensing from their dense medium circuit instrumentation.
Greenfield Washery Design
Specified as a complete system from the outset in new dense medium circuit designs, rather than assembling instrumentation piecemeal.
Closed-Loop Automation Projects
Forms the instrumentation foundation for washeries moving from manual density checks to automated, closed-loop cut-point control.
About John Finlay
Dense Medium Control Instrumentation Supplier in India
Why John Finlay?
5
Real Instruments, One System
Density, magnetite content, level and pressure measurement, plus the control scheme tying them together.
130+
Coal Washery Projects
Completed EPC projects worldwide, including Asia’s largest coking coal washery at 30 MTPA.
AERB Licenses Required
Non-radioactive density measurement throughout the system with no Atomic Energy Regulatory Board licensing burden.
Non-radioactive density measurement throughout the system with no Atomic Energy Regulatory Board licensing burden.
IN
India-Based Support
Manufactured at Hefei John Finlay Mining Equipment Co., Ltd. and supported locally in India for installation, commissioning, spares and service.
Dense Medium Control System | Frequently Asked Questions
Common questions from coal washery process engineers evaluating complete dense medium circuit instrumentation.
Five real instruments: a differential pressure density meter, a magnetic content meter, a differential pressure level transmitter, pressure transmitters for cyclone inlet and pump discharge, and the control scheme and panel that ties them together.
No, the density measurement uses differential pressure, not a radioactive source, so the entire system avoids AERB licensing and the associated radiation-safety compliance burden.
Yes, the system is supplied as individual instruments, as a packaged system, or as a full design-and-implementation scope, depending on what your circuit needs.
Density and magnetite concentration are the two variables that most directly determine cut-point, and this system measures both continuously, feeding a control scheme that closes the loop rather than relying on periodic manual sampling.
One calibration procedure and one spares holding across the plant, rather than managing different calibration routines and spare parts inventories for each instrument type.
Still running your dense medium circuit on periodic manual checks?
Our engineers can help you specify complete, non-radioactive instrumentation for closed-loop cut-point control.
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