Technical Specifications

The DS7700-M is a benchtop digital density meter from A.KRÜSS Optronic, part of the DS7000 series manual sample supply line. It uses oscillating U-tube technology with a borosilicate glass oscillator, and samples are injected manually through a Luer syringe. The viewing window lets you confirm bubble-free filling during injection, and internal Peltier control holds the sample at 10–40 °C. Minimum sample volume is 0.9 ml, and a measurement completes in about 3 seconds after temperature equalisation . The specifications below cover the standard unit; the DS7800-M variant offers ±0.0001 g/cm³ accuracy if your method needs it.

Model/Part Number: DS7700-M

Measurement Performance

• Measurement principle: oscillating U-tube, borosilicate glass oscillator

• Measurement range: 0–3 g/cm³

• Measurement accuracy: ±0.001 g/cm³

• Resolution: confirm against the FRITSCH datasheet for your configuration

• Measurement period: 3 seconds after temperature equalisation

• Minimum sample volume: 0.9 ml

• Pressure range (relative): 0–9 bar

• Sample supply: manual via Luer syringe

• Bubble check: viewing window during injection

Temperature Control

• Temperature control: integrated Peltier

• Temperature control range: 10–40 °C

• Temperature control accuracy: ±0.01 °C

• Temperature measurement accuracy: ±0.02 °C

• Temperature measurement resolution: 0.01 °C

Scales and Methods

• Pre-installed scales: density (g/cm³), relative density, Brix (%Brix), alcohol concentration (Vol.-%), sulfuric acid concentration (% by weight)

• User-defined scales: unlimited

• Methods: over 10,000 possible

• Adjustment: automatic, menu-guided, with air pressure sensor and tempered calibrating agents

Data Integrity and Compliance

• Audit trail: available

• User management: available

• Measured value stabilization: available

• Standards referenced: GMP/GLP, 21 CFR Part 11, pharmacopoeias (USP, BP, JP, Ph. Eur.), FDA, ISO, HACCP, OIML, ASTM, ICUMSA, NIST

Materials and Construction

• Sample contact parts: borosilicate glass, PTFE

• Suitable samples: almost all liquids, emulsions, and pastes

Operation and Interfaces

• Display: 7.0-inch capacitive touchscreen, 800 x 480 pixels, wipeable

• Languages: 6 selectable

• Input options: touchscreen, keyboard, mouse, barcode scanner

• Interfaces: 1x USB, 1x RS-232, 1x Ethernet, LIMS

Physical and Electrical

• Dimensions (W x H x D): 220 x 220 x 430 mm

• Weight: 5.3 kg

• Operating voltage: 100–240 V, 47–63 Hz

• Power consumption (measurement mode): 25 W

• Power consumption (maximum): 120 W

Standard Accessories Included:

• DS7700-M density meter base unit with glass U-tube oscillator

• Drying unit with 3/2-way valve (DS7060)

• Luer filling nozzle and Luer syringes

• Tube set for manual sample supply

• Waste container with lid

• Power cable

• Operating manual

• Test report

Items Excluded:

• Calibration standards (isooctane, n-nonane, ultrapure water, dichlorotoluene available separately)

• Additional syringes and consumables

• Barcode scanner

• Printer for report output

Pre-installation Requirement:
Place the instrument on a rigid, level bench with clearance for the touchscreen and syringe access. Connect to a grounded power supply within the 100–240 V range. Allow the unit to reach ambient temperature before first use if stored in a colder environment. Perform the automatic adjustment with tempered calibrating agents before the first measurement. Confirm the drying unit is connected and the waste container is in place.

Why This Density Meter Fits Labs With Expensive or Limited Samples

Automated density meters earn their price when sample volume is high. When it is not, the DS7700-M digital density meter takes a different approach: manual Luer syringe injection, a 0.9 ml minimum sample, and the same oscillating U-tube measurement principle used across the DS7000 series. You lose the autosampler. You keep the accuracy, the Peltier control, and the chemistry-resistant wetted parts.

The manual format suits more than cost control. Low to high viscosity samples go through the Luer syringe, and the viewing window lets you watch the fill and confirm there are no bubbles before the measurement starts. For pastes and emulsions that would clog a peristaltic pump, that direct control matters. Cleaning follows the same manual logic: inject a suitable solvent until residue dissolves, then let the attached drying unit clear the U-tube.

For buyers sourcing through OS4U, the configuration question is whether the DS7700-M's ±0.001 g/cm³ accuracy covers your method or whether the DS7800-M's ±0.0001 g/cm³ is required, and whether the standard manual set includes the tube and syringe sizes your samples need. The KRÜSS manual sample supply page lists the current set contents and calibration standards.

Key Benefits

Accuracy without the automation premium

The DS7700-M laboratory density meter delivers ±0.001 g/cm³ accuracy with a 3-second measurement. For labs that run modest sample volumes or handle samples too viscous for automated pumps, the manual format removes cost without removing measurement quality.

Small sample, direct control

A 0.9 ml minimum sample volume and a Luer syringe give you direct control over filling. The viewing window confirms bubble-free injection before the reading starts, which matters when a bubble would mean a wasted run on a limited sample.

Peltier control inside the instrument

Internal Peltier control holds the sample at 10–40 °C with ±0.01 °C accuracy, and temperature measurement resolves to 0.01 °C. You are not waiting for ambient equilibration or connecting an external bath.

Scales that cover more than density

Density, relative density, Brix, alcohol concentration, and sulfuric acid concentration are pre-installed, with unlimited user-defined scales. A single instrument covers quality checks that might otherwise need a separate Brix refractometer or alcohol meter.

Chemistry-resistant wetted parts

Borosilicate glass and PTFE contact the sample. That combination handles almost all liquids, emulsions, and pastes, including samples that would attack metal or standard polymer tubing.

Compliance documentation built in

Audit trail, user management, and conformity with 21 CFR Part 11, GMP/GLP, and the major pharmacopoeias. The DS7700-M carries the data integrity features regulated labs need without moving to a higher-tier model.

Solving the Problems That Slow Density Measurement Down

Struggling with expensive samples that make automated purge cycles wasteful? Manual Luer injection with a 0.9 ml minimum sample means you use only what the measurement needs. No automated rinse sequence consuming additional sample.

Handling viscous pastes and emulsions that clog pumps? Manual syringe injection pushes the sample through directly. The viewing window confirms the fill is clean before the measurement starts.

Getting bubble-contaminated readings? The viewing window is there for exactly that reason. You see the fill, you confirm it is bubble-free, and only then does the measurement run.

Worried about temperature drift affecting density? Peltier control holds the sample at the set temperature, and the measurement completes in 3 seconds after equalisation. Temperature is controlled, not assumed.

Needing multiple concentration scales on one instrument? Density, relative density, Brix, alcohol, and sulfuric acid concentration are pre-installed, with user-defined scales available. One instrument covers the concentration checks.

Concerned about aggressive samples attacking the flow path? Borosilicate glass and PTFE contact the sample. The DS7700-M handles chemically challenging liquids without a separate configuration.

Warranty & Support

We provide a 1-year manufacturer’s warranty covering parts and labor. Technical support, installation assistance, and operational training are also available. Replacement parts and consumables are available throughout the product’s service life.

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