Sundy SDDH315t Drying Oven

The SDDH315t Drying Oven is designed for moisture determination in coal, coke and solid biomass fuels, as well as routine laboratory applications including drying, baking, wax melting and heat treatment. It supports both conventional forced-air drying and nitrogen-purge drying, allowing laboratories to perform different drying procedures with a single instrument.

The oven features a temperature range from ambient to 300°C, temperature control accuracy of ±1°C and intelligent PID control for stable, uniform heating. Its spacious stainless-steel chamber, adjustable shelves, delayed-start function and configurable timing modes provide flexible operation for different sample loads and test schedules.

When equipped with the optional nitrogen-purge assembly, the oven can accommodate up to three compact nitrogen drying boxes. The nitrogen valve can be configured to open automatically as the chamber approaches the target temperature, helping reduce gas consumption while maintaining controlled drying conditions.

The SDDH315t is suitable for laboratories in coal, power generation, mining, research and other industrial sectors, and supports moisture testing in accordance with international standards.

Key Features

Dual Forced-Air and Nitrogen-Purge Operation

The oven supports both forced-air drying and nitrogen-purge drying. When equipped with the nitrogen-purge assembly, it can accommodate up to three compact nitrogen drying boxes, making it suitable for different coal ranks while minimizing nitrogen consumption.

Intelligent Nitrogen Control

The nitrogen solenoid valve can be configured to open automatically when the chamber temperature approaches the setpoint. The activation temperature is adjustable, helping laboratories standardize nitrogen-drying procedures and reduce unnecessary gas consumption.

Precise and Stable Temperature Control

Intelligent fuzzy PID control reduces temperature overshoot, shortens stabilization time and improves control accuracy. Two PID control zones, automatic tuning and multi-point temperature correction further enhance performance across different operating temperatures.

Uniform Forced-Air Circulation

An optimized thermal circulation and insulation system distributes heat evenly throughout the chamber. The low-noise circulation motor supports stable airflow and consistent drying conditions across multiple shelf levels.

Flexible Scheduling and Timing

The programmable delayed-start function allows users to schedule heating in advance. Multiple timing modes are available, including constant-temperature timing, total run timing, count-up and count-down operation, with selectable minute or hour units and an audible end-of-test notification.

Large Stainless-Steel Chamber

The vertical design incorporates a 500 × 450 × 550 mm stainless-steel working chamber. Adjustable shelf positions provide flexibility for different sample trays, crucibles and laboratory drying tasks.

Clear and Convenient Operation

The microprocessor controller provides intuitive temperature and time settings, while the double-layer tempered-glass viewing window allows operators to observe the heating process without opening the chamber door.

Comprehensive Safety Protection

Safety functions include overtemperature alarms, temperature-sensor open- and short-circuit detection, automatic heater shutdown, audible and visual warnings, and optional password-protected screen locking for controlled laboratory operation.

Applicable International Standards and Methods

 

StandardStandard TitleApplicable Samples
GB/T 212Proximate Analysis of CoalCoal and coke
GB/T 211Determination of Total Moisture in CoalCoal and coke

Model Selection
ParameterSDDH315tSDDH323SDDH313SDDH306
Picture
Temperature Control RangeAmbient to 300°CAmbient to 300°CAmbient to 300°CAmbient to 300°C
Temperature Control Accuracy±1°C±1°C±1°C±1°C
Temperature Resolution0.1°C0.1°C0.1°C0.1°C
Nitrogen-Purge FunctionOptionalNoNoNo
Main Unit Dimensions636mm×680mm×915mm730mm×670mm×1220636mm×680mm×915mm550mm×550mm×840mm
Chamber Dimensions500mm×450mm×550mm600mm×500mm×750mm500mm×450mm×550mm400mm×360mm×450mm
Weight61kg105kg61kg49kg
Maximum Power2.3 kW3 kW2.3 kW1.6 kW
Power SupplyAC 220 V ±10%, 50 Hz ±1 HzAC 220 V ±10%, 50 Hz ±1 HzAC 220 V ±10%, 50 Hz ±1 HzAC 220 V ±10%, 50 Hz ±1 Hz
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 SDDH315t supports both conventional forced-air drying and nitrogen-purge drying. Users can select the appropriate method according to the sample type and the applicable moisture determination procedure.

The oven is primarily intended for moisture determination in coal, coke and solid biomass fuels. It can also be used for general laboratory applications such as drying, baking, wax melting, heat treatment, sterilization and curing.

The product brochure identifies the following applicable Chinese standards:

  • GB/T 211, Determination of Total Moisture in Coal
  • GB/T 212, Proximate Analysis of Coal

The actual operating temperature, drying atmosphere and test duration should be selected according to the specific method used.

The rated temperature-control range stated in the product brochure is from ambient temperature to 300°C, with a temperature resolution of 0.1°C and temperature-control accuracy of ±1°C.

The controller uses intelligent fuzzy PID regulation. Compared with conventional PID control, this design is intended to reduce temperature overshoot, shorten stabilization time and improve temperature-control accuracy. The controller also supports automatic tuning, two PID control zones and three-stage temperature correction.

Auto-tuning may be performed when the temperature-control response is unsatisfactory, such as excessive overshoot or slow stabilization. During auto-tuning, the chamber temperature may temporarily overshoot significantly, so heat-sensitive samples should be removed before the procedure begins.

A pressure regulator is installed on the nitrogen cylinder. The low-pressure outlet is connected by tubing to the N₂ inlet on the rear panel of the oven. The nitrogen drying box is placed inside the chamber and connected to the corresponding nitrogen port.

The SDDH315t can support up to three nitrogen drying boxes. Each box measures approximately 289 × 153 × 88 mm. The actual number used should allow sufficient space for airflow and safe sample handling.

The operating procedure specifies a nitrogen flow rate of approximately 1 L/min. It also provides the following reference calculation:

Nitrogen flow rate = 15 × furnace volume ÷ 60

The flow should be adjusted using the flow-control device on the front of the oven.

Yes. When the nitrogen solenoid-valve function is enabled, the oven can automatically open the nitrogen valve as the chamber temperature approaches the setpoint. The activation point is determined by the configurable temperature-deviation parameter.

The valve-control deviation parameter determines how far below the set temperature nitrogen purging begins. For example, a value of 20°C means that the valve opens when the measured temperature is higher than the setpoint minus 20°C. A value of 0°C means that nitrogen begins after the chamber reaches the set temperature.

Nitrogen provides a controlled, low-oxygen drying atmosphere for methods that require nitrogen drying. The dedicated drying box directs nitrogen around the sample while limiting unnecessary gas consumption. Operators must ensure that neither the inlet nor the outlet of the box is blocked by crucibles or sample containers.

Sample trays must not be stacked, placed directly against the chamber walls or arranged in a way that blocks the central air passage. Sufficient clearance must be maintained between adjacent trays and between the trays and the chamber walls to ensure effective hot-air circulation.

No. The manual recommends that the loaded area should generally not exceed approximately two-thirds of the available shelf surface. Overloading may restrict airflow, reduce drying uniformity and cause localized overheating.

Yes. The circulation fan should remain operating while the oven is heating. Switching off the fan during temperature rise can impair heat distribution and accelerate ageing of the heating element.

The controller supports three timing configurations:

  • No timing
  • Constant-temperature timing
  • Total operating-time timing

It also supports count-up or count-down operation, with minutes or hours selectable as the timing unit.

In constant-temperature timing mode, timing begins only after the measured chamber temperature enters the defined constant-temperature range around the setpoint. This prevents the heat-up period from being included in the effective drying time.

Yes. The appointment or delayed-start function allows the operator to set a waiting period before heating begins. During the delay period, the controller keeps the heating output switched off and displays the remaining time.

If the temperature sensor is open-circuit, short-circuit, outside its measurement range or otherwise abnormal, the controller displays a fault indication, activates audible and visual alarms and automatically disconnects the heating output. The sensor and its wiring should be inspected before operation resumes.

The oven must not be used for flammable, explosive, toxic or strongly corrosive materials. It must be installed level, connected to protective earth and operated with the specified power supply. During operation, the top surface, viewing window and exhaust areas may become hot and must not be touched. Maintenance and internal repairs should only be performed by qualified personnel.

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