Frequently Asked Questions

Your questions – our answers

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Do you have a question? We are here to answer. If you don’t find your question here, contact us! Details can be found on the contact page.

Sample material

It can be used for dry materials regardless of their shape (regular shape, porous or non-porous, powdery, granular).

Gas pycnometers are generally used for skeletal density measurement of dry materials. In principle, density determination of liquids and pastes is also possible.

The grain size is irrelevant for the measurement, but the material must not exceed the size of the measuring cup.

For unbiased measurements, the sample must have only a vanishingly low vapor pressure, since the gases and vapors released during the measurement influence the equilibrium pressures.

Yes, because as the title of DIN EN ISO 1183-3 (Determination of the density of non-foamed plastics Part 3: Gas pycnometer method) already suggests, this is an analysis by means of a gas pycnometer, which the BULKINSPECTOR is.

DIN 60 (Plastics - Determination of the apparent density of molding compounds which can flow through a standardized funnel (bulk density)) is a standard for the determination of bulk density, which generally cannot be determined with a gas pycnometer.

Sample feeding

In the standard equipment the BULKINSPECTOR has measuring cups of the size 130 / 65 / 10 cm³.

130cm³ -> Ø57mm x53mm (not cylindrical), Sample diameter max. 40mm
65cm³ -> Ø47mm x41mm (not cylindrical), Sample diameter max. 40mm
10cm³ -> Ø25mm x22mm (not cylindrical), Sample diameter max. 20mm

The BULKINSPECTOR was developed for the automatic determination of density and can therefore be integrated into existing processes for on-line analysis. The type of sampling from a bulk or lump material and the feeding to the pycnometer must be planned for the individual case. With our sampling know-how we are glad to be at your disposal for planning.

Sample magazines with 25 and 50 places are optionally available.

In principle yes, but these must not exceed the max. dimensions of the 130 cm³ measuring cup.

Measurement (method)

Weight, volume and density of the sample. Also the measurement uncertainty of repeat measurements.

Normally, the measuring gas used in gas pycnometers is an inert gas, e.g. helium, which does not react with solids (i.e. reacts, adsorbs) and whose atom is small enough to penetrate even porous material. However, depending on the purpose of the measurement, other gases or oxygen can also be used.

0 … 510 g ± 0,0001 g.

Measuring temperatures between 15 and 35°C can be set.

The measurement uncertainty is ± 0.02%.

The analysis time for a full cycle depends on the type of sample, the size of the measuring vessel, the measuring gas used and the number of repeat measurements. Therefore, the duration of approx. 3 - 6 minutes can only be given as a guide value.

Technical specification

The BULKINSPECTOR has the following dimensions (width x depth x height) 1100 x 675 x 855 mm.

The weight is 190 kg.

The temperature of the device is controlled by Peltier elements.

German, English, Portuguese, Italian, Spanish, Dutch, Russian, French.

Connections, interfaces & data transfer

AC 110 V/16 A/60 Hz, AC 230 V/10 A/50 Hz.

No, the machine sets up its own WiFi for operation via tablet.

The BULKINSPECTOR has a network interface (LAN or RJ45) and has its own WiFi network.

If your PC has an bluetooth adapter, the measurement results can be sent via the bluetooth of the supplied tablet.

Yes, the BULKINSPECTOR can be operated from any computer in the same network via the browser. No additional software is necessary.

Of course, the BULKINSPECTOR can also be used in the USA. It can be operated with AC 110 V/16 A/60 Hz, AC 230 V/10 A/50 Hz.

Maintenance & Service

You can test the BULKINSPECTOR in our laboratory and test center in Mülheim an der Ruhr, Germany.

It is necessary to manually clean the measuring cups at regular intervals. How long these intervals are depends on the sample material.

You can always let us know your concern using the form available on the website. In addition, our support team will be happy to assist you during our normal business hours. You can find all information on our contact page.

The main maintenance tasks on the BULKINSPECTOR are:
Regular cleaning of the measuring cups
Regular recalibration with a calibration ball, can also be done automatically by BULKINSPECTOR.
Replacement of the ultra-fine filter in the gas line, especially in case of frequent measurement of ultra-fine particles.

The scope of the required wear and spare parts depends on the material to be analyzed and the operating conditions and can only be determined individually.

Equipment & Accessories

The following accessories are available for the BULKINSPECTOR:
Measuring beaker size 130/65/10 cm³.
Sample magazine with 25/50 sample containers
Underframes with/without sound insulation
Calibration balls
Vacuum cleaner
Compressor
Adapter set for the connection of a larger waste container
Sampling devices for the integration of the BULKINSPECTOR as on-line measuring device into running processes.

The tablet for using the app control of the BULKINSPECTOR is of course included.

Basics & Explanation of Terms

The BULKINSPECTOR is the only pycnometer on the market in which the measuring cup is automatically inserted into the measuring cell by a handling device. Furthermore, the weighing of the sample is done by a scale integrated in the BULKINSPECTOR, so that no additional handling by the operator is necessary.
This also offers the possibility to connect a sample magazine in front of the device or to integrate it into the on-line monitoring of processes.

The BULKINSPECTOR is a gas pycnometer. It can be used to determine the density (skeletal density) of solids, porous and bulk materials, including powders, with high precision.

Gas pycnometers are usually based on the solids to be measured displacing their volume of test gas in a sample chamber. Typically, helium is used as the test gas because it does not interact (i.e., react or adsorb) with solids and the atom is small enough to penetrate even porous material.

Our BULKINSPECTOR is a constant volume gas pycnometer.
This type of measurement is the most widely used and is also directly mentioned as a method in various standards and pharmacopoeias.

After the material sample has been taken up in a measuring cup, this is introduced into the measuring cell via a handling device and the volume of the sample is determined there according to the selected presettings.
After the volume has been determined several times, the handling device takes over the further transport to the balance for the determination of the sample mass.
Once the mass of the sample is known, the density of the solid can be calculated. This is also referred to as the true density.
Finally, the handling device removes the measuring cup and takes the measured material sample to the emptying device. There, the measuring cup is additionally cleaned with compressed air and is then ready for the next sample.

The skeletal density, also called pure density, absolute density or true density, denotes the density of the material part of a solid in any state of aggregation, i.e. without taking into account the volume of any cavities it may contain. In the case of porous solids, the true density is determined by crushing and grinding the material until its particles no longer contain any pores (see also tapped density). The counterpart to the pure density of porous materials is the bulk density, in the determination of which the pore volume is very well taken into account. Gas pycnometers with helium as the test gas are used as a good approximation for determining the true density.
In the case of heaps, the pure density in grain analysis is obtained from weighing and extrapolation. The counterpart to the pure density of heaps is the bulk density.

Source: This article uses material from the Wikipedia article "Pure density" and is licensed under the GNU Free Documentation License. A list of authors is available in Wikipedia.

The skeletal density or pure density, absolute density or true density, denotes the density without taking into account the volume of any cavities it may contain.

Bulk density, on the other hand, is the density of a bulk material and a continuous fluid that fills the cavities between the particles. The fluid can also be air. The individual components must not dissolve into each other.

Source: This article is based on articles from the free encyclopedia Wikipedia and is licensed under the GNU Free Documentation License. A list of authors is available in Wikipedia.

Tapped density (synonym: shaking density) which describes the density of a heap (solid) which has already been compacted by tamping or shaking compared to its bulk density.

Source: This article is based on various articles from the free encyclopedia Wikipedia and is licensed under the GNU Free Documentation License. A list of authors is available in Wikipedia.

Bulk density, also called apparent or geometric density or bulk density, it is the density of a porous solid based on volume including pore spaces.

Source: This article is based on various articles from the free encyclopedia Wikipedia and is licensed under the GNU Free Documentation License. A list of authors is available in Wikipedia.

If the personnel costs, including the additional costs of a laboratory assistant, are estimated at approx. 65,000 €/year, the BULKINSPECTOR pays for itself after only one year, if the laboratory assistant is completely relieved of the measuring activities. If the lab technician is only relieved on a half-day basis, the amortization period is 2 years.