Atmospheric & Vacuum Drying Constant Weight Tester

Choose vacuum drying when the sample is heat-sensitive (decomposes, discolours or melts at high temperature), oxidation-prone, or contains low-boiling solvents/volatiles. Lowering the pressure markedly reduces the boiling point of water so drying completes at a lower temperature, preventing non-water volatile loss from being counted as moisture.

Yes. Dishes are 75 mL standard and the actual sample mass follows your method; with a 0.3 mg constant-weight criterion and a 0.1 mg balance, results stay stable even at low sample masses. For ultra-micro samples, please confirm the approach with us first.

It depends on how much heat the sample tolerates. Atmospheric mode performs heated loss on drying and moisture content, replacing the oven, desiccator and balance in one unit. Vacuum mode dries at low temperature inside an evacuable chamber — lowering the pressure lowers the boiling point of water, so moisture leaves at a lower temperature, which suits heat-sensitive and oxidation-prone samples that would otherwise decompose or oxidise. Both modes share the same constant-weight criterion (0.3 mg, at 0.1 mg balance resolution), so results are directly comparable.

Pharmacopoeias and GB methods usually define constant weight as a difference of no more than 0.3 mg between two consecutive weighings (a few standards use 0.5 mg or 0.2 mg). The instrument judges at ≤0.3 mg by default, which covers most pharmacopoeia and food-contact methods; if your standard specifies another criterion, confirm applicability with an engineer before ordering.

No. Overall migration is the total non-volatile substance transferred from a food-contact material under a specified simulant and contact condition; evaporation residue is the mass left after the soak or extract solution is taken to dryness; non-volatile matter refers specifically to the fraction that does not volatilise at that temperature. Their sample preparation and simulants differ, but all three end with evaporation, drying and constant-weight weighing, so one constant-weight tester serves them all.

They are not equivalent. Loss on drying is everything the sample loses at the specified temperature — water, residual solvent and other volatile components; water content means H₂O specifically and is usually determined by Karl Fischer titration or a dedicated moisture analyser. The two figures approach each other only when water is the sole volatile present. A compliance report should state the method and conditions for each.

The four differ in temperature, duration and preparation, but all end in the same high-temperature ignition, cooling and constant-weight weighing step, so one high-temperature instrument covers them. Ignition residue is the inorganic residue left after high-temperature ignition; ash is what remains after food, pharmaceutical or herbal material is ignited at a specified temperature; acid-insoluble ash treats the ash further with acid and keeps only the insoluble part, to reveal sand and other extraneous matter; loss on ignition (LOI) is the mass percentage lost by solid waste, building materials or minerals at high temperature.

Yes. Standard models ship as-is, while chamber count, specimen size, fixtures, temperature range and software modules (including the GMP Computerized System module) can be tailored to your SOP and URS. IQ/OQ/PQ validation documentation packages are available.

Standard models usually ship in 4–8 weeks; customised builds depend on the agreed scope. Instruments are packed in export wooden cases and can move by sea, air or rail. We supply proforma invoice, packing list and certificate of origin (CO / Form E), and work under EXW, FOB, CIF or DAP terms.

We provide remote installation guidance, bilingual (Chinese/English) manuals and video training; on-site commissioning by our engineers is available. Users can self-calibrate with standard weights, reference films or calibrated leak standards, and third-party calibration certificates can be supplied.

The instrument carries a 12-month warranty from acceptance plus lifetime maintenance support. Consumables (molecular sieve, desiccant, sealing grease, printer paper) are kept in long-term stock, and key components are international brands available worldwide. We respond to technical enquiries within 24 hours.

Yes. Every instrument lists its applicable standards on the specification page (ASTM, ISO, GB, YBB, Chinese Pharmacopoeia, USP, EP, JIS, DIN, TAPPI and more). The software outputs raw records and reports suitable for audit trails, with an optional GMP / FDA 21 CFR Part 11 compliance module.

The software ships with Chinese and English interfaces; other languages can be added on request. Data export is available over RS232, USB, Ethernet or Wi-Fi, and reports can be exported to Excel, PDF or structured files for LIMS integration.