SDMF300 Muffle Furnace

The SDMF300 Muffle Furnace is a programmable high-temperature furnace designed for the determination of ash and volatile matter in coal, coke and solid biomass fuels. It can also be used for general laboratory heating, ignition, ashing, drying and other thermal treatment procedures.

With a temperature range from ambient to 1000°C, PID temperature control and multiple preconfigured test programs, the SDMF300 provides stable and repeatable heating conditions for routine fuel analysis and laboratory applications. Dedicated programs are available for slow ashing, rapid ashing, volatile-matter determination and Roga Index testing, while two customizable general-purpose modes allow users to create their own heating profiles.

The furnace features a large LCD interface, one-touch test startup and real-time temperature-curve display, making the heating process easy to operate and monitor. Its high-performance heating elements, efficient thermal insulation and comprehensive safety protection help ensure reliable long-term operation in coal laboratories, power plants, metallurgical facilities, cement plants, environmental laboratories and research institutions.

Key Features

Multiple Dedicated Test Programs

The SDMF300 includes independent programs for slow ashing, two rapid ashing methods, volatile matter determination, Roga Index testing and general-purpose heating procedures, covering the main thermal analysis requirements of coal, coke and biomass laboratories.

Flexible Programmable Heating

Two customizable test modes allow users to create specific heating procedures. Up to six heating stages can be programmed with individually defined temperatures, heating times and holding times.

Accurate and Stable Temperature Control

PID temperature-control technology provides precise regulation of heating rates, target temperatures and holding periods. The furnace offers a temperature range from ambient to 1000°C, with 1°C resolution and ±1°C control accuracy.

Optimized Sample Positioning

A dedicated positioning device for the volatile-matter crucible rack helps place samples accurately within the constant-temperature zone, supporting reliable temperature recovery and consistent test conditions.

Simple and Intuitive Operation

The large LCD display, shortcut keys and one-touch startup simplify daily operation. Real-time temperature curves and selectable count-up or countdown timing make the complete heating process easy to monitor.

Reliable Thermal Performance

High-quality heating elements, efficient insulation materials and an enclosed furnace structure provide excellent temperature stability and uniformity during prolonged high-temperature operation.

Comprehensive Safety Protection

The instrument provides alarms for thermocouple open circuit, short circuit, reversed connection, overheating and heating-circuit failure. Automatic power cutoff helps protect both the instrument and the operator.

Applicable International Standards and Methods

 

StandardStandard TitleApplicable Samples
GB/T 212Proximate Analysis of CoalCoal and coke

Model Selection Guide
ParameterSDMF300SDMF300C
Furnace Temperature RangeAmbient to 1000°CAmbient to 1000°C
Maximum Power3.5 kW3.5 kW
Temperature Resolution1°C1°C
Maximum Heating Rate100°C/min100°C/min
Furnace Chamber Dimensions298 × 203 × 121 mm (L × W × H)298 × 203 × 121 mm (L × W × H)
Exposed Heating ElementsYesNo
Electronic Door LockNoNo
Application Notes

We are compiling our practical application experience into a growing collection of technical articles that will be published here regularly.

If you have an immediate analytical challenge before then—whether in mining, energy, advanced materials, or PFAS analysis—contact the Sundy Technology Application Laboratory. We provide customized method development, application optimization, and technical support to help you achieve reliable analytical results.

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Customer Testimonials

We have provided a complete set of Sundy testing solutions, including bomb calorimeter, sulfur analyzer, and thermogravimetric analyzer, to the fuel analysis laboratory of Kavçim Cement, a leading integrated cement plant on Turkey’s Black Sea coast. Sundy’s standardized instrument performance bring outstanding practical value to end users. The upgraded solution significantly simplifies daily operations, lowers manual intervention and maintenance costs, and unifies data consistency for routine fuel analysis.

We are very satisfied with Sundy’s product quality and technical support, and will continue to promote and recommend Sundy analytical instruments for more industrial laboratory projects in Turkey.

Dr. Karahan, POTANTEK

After more than 10 years of continuous cooperation and market verification, we confirm that Sundy’s products, especially its automatic calorimeters and elemental analyzers, have high precise temperature control, accurate testing results, and ultra-low failure rate. All products are fully compliant with international ISO and ASTM standard, completely meeting the testing demands of coal laboratories, power plants, industrial enterprises, universities and scientific research institutions.

We highly recognize Hunan Sundy Science and Technology’s strong production capacity, standardized quality management system, professional technical support team and excellent business credibility. In all our cooperation cases, Sundy has always demonstrated professionalism, reliability and a customer-oriented service attitude.

Dr. Kim, YEONJIN
FAQs

The SDMF300 is primarily designed for the determination of ash and volatile matter in coal, coke and solid biomass fuels. It can also be used for laboratory heating, ignition, ashing, drying and other high-temperature treatment procedures.

The furnace can be controlled from ambient temperature up to 1000°C. Its temperature resolution is 1°C, and the specified temperature-control accuracy is ±1°C.

The SDMF300 uses a PID control algorithm to regulate the furnace temperature, heating rate and holding time according to the selected test program or user-defined parameters.

The instrument includes dedicated programs for slow ashing, Rapid Ash Method 1, Rapid Ash Method 2, biomass ash, volatile matter determination, Roga Index testing, General Program 1 and General Program 2.

Rapid Ash Method 1 requires samples to be gradually introduced into the furnace at approximately 850°C before the temperature returns to 815°C for the specified holding period.

Rapid Ash Method 2 allows the samples to be loaded at 500°C, after which the furnace automatically heats to 815°C and maintains the programmed test conditions.

In the slow-ashing program, the sample is loaded below 100°C. The furnace heats to 500°C over a period of not less than 30 minutes, holds at 500°C for 30 minutes, then heats to 815°C and holds for one hour. An additional 20-minute check ignition can be performed when required.

For coal volatile matter testing, the furnace is normally stabilized at a sample-loading temperature of 920°C. After the sample is inserted, the furnace is required to recover to 900°C within three minutes, and the total heating time is seven minutes.

The sample-loading temperature can be adjusted between 900°C and 940°C.

The volatile matter result is sensitive to the actual temperature experienced by the sample. The dedicated crucible-rack positioning structure helps place the crucibles accurately within the constant-temperature zone, improving temperature recovery consistency and test repeatability.

Yes. The recovery power for volatile matter, Roga Index and General Program 2 can be adjusted from 1% to 100%.

A higher recovery-power setting generally shortens the temperature-recovery time, while a lower setting produces slower recovery.

General Program 1 is intended for customized multistage heating procedures similar to ash determination.

Users can configure up to six heating stages. The target temperature, heating time and holding time can be set independently for each stage.

General Program 2 allows users to configure:

  • Sample-loading temperature
  • Heating time
  • Temperature-recovery power
  • Total test time
  • Maximum recovery time
  • Test temperature

This mode is suitable for customized procedures similar to volatile matter testing.

Yes. The timing mode can be configured as either count-up or countdown according to the operator’s preference. The selected timing mode applies during the constant-temperature stage of the test.

Yes. The LCD interface can display the real-time furnace temperature curve. The display range automatically adjusts according to the selected test procedure.

The temperature-curve screen can also be disabled in the instrument settings when it is not required.

The instrument provides protection and alarm functions for:

  • Thermocouple open circuit
  • Thermocouple short circuit
  • Reversed thermocouple connection
  • Abnormal cold-junction temperature
  • Furnace overtemperature
  • Heating-circuit failure

In an overtemperature condition, the instrument can automatically cut off the heating power.

No. The SDMF300 does not include the electronic furnace-door lock described for the SDIMF200 model.

Operators must therefore follow the specified test procedures and avoid opening the furnace door during critical heating stages.

No. Host-computer monitoring, centralized instrument control and software-based data management are functions of the SDIMF200 and are not supported by the SDMF300.

The SDMF300 is operated through its local LCD display and control panel.

The recommended operating environment is:

  • Ambient temperature: 0–35°C
  • Relative humidity: no more than 90%
  • No obvious smoke or airborne dust
  • No strong magnetic fields or vibration sources
  • No flammable, explosive or corrosive substances nearby
  • A dry and well-ventilated laboratory environment

The furnace should be positioned at least 25 cm from the wall and 35 cm from other objects.

The required power supply is AC 220 ± 10 V, 50 ± 1 Hz, with reliable protective grounding.

The fuse or circuit protection for the heating-power supply should be rated at no less than 25 A. The maximum instrument power is 3.5 kW.

Temperature calibration includes cold-junction correction and thermocouple coefficient adjustment.

The displayed temperature should first be compared with the ambient temperature. The furnace temperature should then be checked at representative operating points such as 500°C, 815°C or 850°C, and 920°C using the thermocouple electromotive force and the applicable K-type thermocouple reference table.

Temperature calibration should be performed by trained personnel.

Operators should regularly:

  • Keep the furnace clean and dry
  • Prevent dust, corrosive liquids and gases from entering the instrument
  • Inspect the insulation material and furnace chamber
  • Check the thermocouple and electrical connections
  • Verify the power-supply voltage and load capacity
  • Calibrate the furnace temperature periodically
  • Open and close the furnace door carefully to avoid damaging the insulation

When the instrument will not be used for an extended period, suitable dust protection and periodic inspection are recommended.

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