Kjeldahl Digester DW-SH220F

The DW-SH220F Kjeldahl Digester is designed for high-throughput sample digestion before Kjeldahl nitrogen and protein analysis. Its 20-position graphite heating block provides uniform heat transfer across all digestion tubes. PID temperature control, rapid heating, corrosion-resistant construction, and an integrated gas collection system help laboratories achieve efficient and consistent digestion while improving operational safety.

RT +5°C to 450°C
±0.1°C Temp. Stability/Precision
Reaches 450°C in 25 Minutes
300 mL, Ø42 mm Digestion Tubes

Description
Specification
Why Drawell?

Features of DW- SH220F Kjeldahl Digester

Reaches 450°C in 25 minutes with PID temperature control.
Uniform graphite-block heating for consistent digestion.
4.3-inch color screen for real-time monitoring.
Corrosion-resistant design for strong-acid digestion.
Gas collection hood with suction pump for fume removal.
Over-current, over-temperature, and overload protection.
Air-duct insulation maintains uniform tube temperature and stable reflux

Applications of DW- SH220F Kjeldahl Digester

Application of DW SH220F Kjeldahl Digester 7

Application of DW SH220F Kjeldahl Digester 4

Application of DW SH220F Kjeldahl Digester 6

Application of DW SH220F Kjeldahl Digester 5

Product Display

Troubleshooting and Solutions

Causes: Rapid temperature rise, high fat/sugar content in samples, excessive sample weight, no anti-bumping boiling stones added.

Solutions: Adopt gradient low-temperature heating (hold at 180°C for 30 min first before raising temperature); reduce sample weighing amount; add glass boiling stones; pre-carbonize high-sugar and high-fat samples at low temperature in advance.

Causes: Sulfate precipitates after sulfuric acid cools down; incomplete digestion; excessive rapid cooling.

Solutions: Pour waste liquid while hot; add a small amount of pure water for dilution before cooling. For residual black dirt, add dilute sulfuric acid for reheating digestion, then soak and clean after cooling.

Causes: Aging heating wires, carbon deposits inside heating holes leading to poor heat conduction, offset temperature control sensors, uncovered heat insulation cover.

Solutions: Clean residues on inner walls of heating holes; calibrate temperature sensors; contact after-sales service to replace aged heating units; keep the furnace cover closed during the whole digestion process.

White smoke is normal, which is SO₃ produced by high-temperature decomposition of concentrated sulfuric acid.

Precautions: Equip waste gas absorption device (filled with water or dilute alkali for absorption); fully turn on laboratory ventilation. Avoid smoke corroding equipment and irritating respiratory tracts. Do not conduct digestion for a long time without waste gas absorption device.

Judgment standard: Stop heating when the digestive liquid turns clear light blue-green without black particles, then keep constant temperature for another 30 minutes.

Hazards of over-digestion: Long-time high temperature will cause trace loss of nitrogen elements, resulting in lower crude protein test values. Do not heat at high temperature for extra long time.

FAQ

The digester can process up to 20 samples in one batch.

The maximum specified temperature is 450°C.

The PID-controlled heating system reaches 450°C in approximately 25 minutes.

The specified digestion tube size is 300 mL with a diameter of Ø42 mm.

The brochure specifies both heating block temperature stability and precision as ±0.1°C.

The system includes a gas collection hood and suction pump for collecting fumes generated during digestion.

The instrument features a corrosion-resistant coated design intended for experiments involving strong acids.

The DW-SH220F includes over-current protection, high-temperature warning, and overload protection.

The supplied brochure describes the DW-SH220F as a digestion unit. A separate Kjeldahl distillation or analysis system may be required for the subsequent determination stage.

Specifications of DW- SH220F Kjeldahl Digester

DW-SH220F
Temperature range	RT + 5℃ to 450℃
Stability of the heating block temperature	± 0.1℃
Precision of the heating block temperature	± 0.1℃
Heating method	Infrared heating and high purity graphite conduction
Heating insulation method	Unique air duct insulation technology
Digestion tube	300mL, Φ42mm
Capacity per bath	20pcs
Power	220AVC±10%， 50Hz, consumption: 3.6Kw
Dimension	515mm×421mm×211mm
Weight net	25Kg

	DW-SH420F	DW-SH220F
Temperature range	Room temperature +5 – 450℃	●
Temperature accuracy	±1℃	●
Heating method	Infrared heating and high-purity graphite conduction	●
Heating insulation method	unique air duct insulation technology	●
Digestion tube capacity	300ml	300ml
Capacity per batch	20pcs/batch	20pcs/batch
Program storage	500	3
Temperature Ramping	5	5
Time Selection	1 to 1440 Minutes – 1 Minute Steps	●
Tube rack support	YES	NO
Power	3600W	●
Dimensions (mm)	515X458X730	534X453X218
Heating method	Infrared heating and high-purity graphite conduction	●
Heating insulation method	unique air duct insulation technology	●
Tube rack support	YES	NO

	DW-SH220N/SH420	DW-SH220F/SH420F
Tubes Capacity	280mL	300mL/280mL
Kjeldahl Model	K9860/K9840/K1100F	K9860/K9840/K1100F
Scrubber	S402	S402

	DW-SH420	DW-SH420F	DW-SH220N	DW-SH220F
Heating method	Infrared heating and high-purity graphite conduction	●	●	●
Heating insulation method	unique air duct insulation technology	●	●	●
Temperature Ramping	YES	YES	NO	NO
Tube rack support	YES	YES	NO	NO

Why Choose Us?

One-Station Shopping

“Multiple suppliers” have always been an issue in the procurement process. Drawell as a one-stop laboratory equipment and scientific instruments supplier, can perfectly solve this problem. In addition to manufacturing our own equipment, we also represent other laboratory equipment. Our product lines are rich and diverse at competitive prices. Provide one-stop service to customers.

Customer-centric Services

User Training – Training by Drawell skilled engineers about installation, debug tests, technical services, etc. It can happen in our factory in China, or at the site in the customers’ country. Cost depends on where and when the training happens.

Online Support

To discuss the problem and get it resolved, online chats, real-time video calls, and remote guidance. For the after-sales stage, our online technical guidance is free and ready forever.

100% Quality Guarantee Policy

1 year free official warranty, including repairing quality-damaged parts, and offering replacements of selected parts (shipping cost is extra). 5% of the product price is charged for extending the warranty before the end of the official warranty.