Advanced Sand Sedimentation Analyzer:

Updated 02-Feb-11 18:30h

MacroGranometer™ is a computerized sedimentation analyzer of water-insoluble, sand-sized material, using gravity sedimentation from a single level (stratified sedimentation) in water. Employing the most sophisticated solutions makes it the unique tool for sand sedimentology, which provides high quality and meaningful results, with added operational and maintenance ease, and a variety of outputs.

MacroGranometer™ measures the sedimentation velocity distribution, and its data processing program, SedVar™, converts it into a distribution of other sedimentation variables, such as shape-specified grain size. For the conversion, the equation for drag coefficient as a function of Reynolds' number and grain shape developed by J. Brezina (1979b) is utilized.

Distributions of the following sedimentation variables are available:

The grain parameters density and shape can each be quantified as a distribution. This is possible from samples of nearly equal grain size such as narrow sieve fractions.

Our processing software SedVar also computes distributions of the grain sedimentational Reynolds' number; these distributions, similarly to those of PSI sedimentation velocity, feature a less negative skewness than the pertinent PHI grain size distributions. In fact, the skewness of the grain sedimentational Reynolds' number distributions has a medium value between the most negatively skewed PHI, and least negatively skewed PSI distributions). Not only that our Reynolds' number distributions use the shape-specified grain size but can be computed for samples of nearly equal grain size (narrow sieve fractions with varying grain density), and for nearly equal grain density.

The MacroGranometer system is shown on the schematic view below:

sedi1.gif (36927 bytes)



GRM™, Measuring & Operational Software
example of the GRM™ analysis window

(User's 486 66 MHz DX2 PC or higher, with 1 LPT and 1 COM interfaces)

Control & Measuring Electronic Box
CFM automatic digital amplifier, control & sensor PCBs,
power supply, cable distributor

SedVar™, Processing Software

The schematic view of the MacroGranometer™
the sedimentation length L is usually 180 cm

3-D view of the Upper Part of the Sedimentation Tube: Venetian Blind (sample introduction)

3-D view of the MacroGranometer's™ Sedimentation Tube (larger view: klick)

Open lamellae of the Venetian Blind (without rotational magnet etc.)




Underwater Balance Body  (larger view: klick)

3D-View of the Underwater Balance Body 


3-D view of the Lower Part of the Sedimentation Tube with the Underwater Balance  (larger view: klick)

Our measuring software GRM runs on the user's 486 DX2 66 MHz PC or higher, under MS DOS 6.2 or higher. It controls the system's operation and stores the measured data as ASCII files.

Our processing software SedVar runs on the user's MS Windows 98 PC or higher. It processes the measured PSI local sedimentation velocity distributions. SedVar™ consists of three parts:

  1. SedVar™, distribution conversion,
  2. SedGraph™, graphical output generator,
  3. Sed 3D Graph™, 3D plot of a multiple distribution graph.
MEASURING RANGE: 0.016 - 4 mm
  quartz density materials:  0.044 - 4 mm
heavier materials:  may be finer, such as 0.016 - 1 mm;
SAMPLE SIZE: smallest, statistically representative samples of
15,000 - 20,000 grains (0.1 - 5 gram);
settling rate resolution: 0.02 PSI
weight resolution: 0.01 %

RESULTS: semi graphic and full graphic print-outs showing distributions of the six sedimentation variables listed above, such as laboratory, standard and local PSI sedimentation velocities, PHI grain size, density, shape factor and Reynolds' number including either variable size, density or shape factor. The standard sedimentation velocity and Reynolds' number are available also for sieve fractions (constant size) and heavy liquid fractions (constant size and density); each variable is resolved into 401 logarithmically equidistant intervals.

Mean, spread, asymmetry & peakedness are calculated as moment and percentile distribution characteristics of each variable. Other characteristics may be included as you wish.

The program Sed 3D Graph™ (part of the SedVar™ program) permits a graphical display of a group of distributions, either according to the samples' geographic horizontal or vertical location, or according to another desired variable. For example, a group of PSI-settling velocity (or grain density) distributions, each from a constant grain size fraction, can be plotted according to their PHI-grain size.

The optional program SHAPE™ provides the possibility of separating as many as five mixed distribution components, each normally distributed. This program can match a sieve analysis to the sedimentation analysis of the same sample, and compute Shape Factor values to each 0.02-PSI sedimentation velocity. Our SedVar™ program can use this set of the variable SF values to adjust the sedimentation grain size distributions of similar samples (the results of the MacroGranometer™) to the sieving; in other words, it can simulate the sieving errors.

Examples  of our clients who use the instrument

  1. Department of Geological Sciences, University of Trieste, Italy (click);

  2. Department of Geology, University of Vienna, Austria (click).

Example of a PSI distribution decomposed into Gaussian components

SAMPLE:                      FileName:                         sed122.dat

A sand fraction, consisting of nearly monosize grains, made by precision sieves with circular holes:


black sand

sample 13

at a 90° intersection of beaches


near Casusay

Venezuela Bay

about 110 km NNW of Maracaibo

Sampling Date:


low tide

tide amplitude: about 75 cm

Analysis date, time:

1981-2-1, 16:55h

Tmean                                  = 24.76°C


precision wet vibration sieving

circular holes ± 0,002 mm


1.770 ±0.0639 PHI

= 0.297 ±0.013 mm

Average of 8 sample
split analyses:

Total Mass:
Mean Sample
Split Mass:

0.6916 gram

0.08645 gram

SF = 0.63 (calculated Corey‘s Shape Factor)

Glab = 980.962 gal (cm/sec2)

Decomposed MonoSize Polymineral (1.77 PHI = 0.297mm) Fraction in PSI

 PSI Distribution of MonoSize (1.77PHI=0.297mm) Polymineral Fraction Decomposed into 4 Gaussian Components

Our Sand Sedimentation Analyzer (MacroGranometer) measured at 0.02 PSI intervals (X-axis).
No data manipulation such as “smoothing“ has been used.
The smoothness of the 1st derivative,“Input d%“, shows the analysis quality.
Our Program SHAPE identified 4 Gaussian Components (Comp 1, Comp 2, Comp 3 and Comp 4).


Our Program SHAPE™ (based on the method by Isobel CLARK, 1977) decomposed the analyzed PSI distribution into
4 Gaussian components with the following 11 parameters -
4 means, 4 standard deviations, 3 percentages (the 4th one is the rest up to 100%)



St. Dev.



Minerals (calculated & confirmed)


















quartz, feldspars, calcite






porous calcite (fossils)

Goodness of fit


χ2 <0.01

Our Program NGRM calculated density from the constant PHI size and each PSI-mean value.
The density values of each component match the minerals identified microscopically and by X-ray diffraction analysis.

Our Program SedVar™ converted the variable PSI into a log density distribution (not shown here).
The ultimately lowest Chi-square value, χ2 <0.01, reveals the decomposition quality.

Client's preparation for our installation of the instrument

The client should build and fix two steel Bases to carry both the Air Shock Absorbers, and an operation platform before our installation. Also, a container with about 100 liter distilled water should be available a few days before our installation (the container should be positioned above the top of the sedimentation column in order its water will be warmer, and without dissolved air).

Calibration Experiment
for IUGS-COS Working Group on Modern Methods of Grain Size Analysis, 1986 - 1989,
chaired by James P. M. Syvitski 

J. Brezina collected and processed the data of the Experiment from 17 participants, however, he did not complete the final processing before the publication deadline of the book by J. P. M. Syvitski (click on the author's review of the Syvitski's book in Basin Research 4/1992).

Below are shown the calibration results of one of the MacroGranometer™ users, the participant No. 14 (in the Syvitski's book quoted under instrument code ST3), in comparison with a precision 0.25-PHI sieving, made by participant No. 7.

The calibration samples consisted of glass spheres with exactly determined density of each of the five mixture components; three sand samples were mixtures of up to three components. J. Brezina produced each mixture component on 65-millimeter screens featuring galvanically deposited meshes with circular holes, with the aid of random vibration of the glass spheres in alcohol suspension on each screen. The minimum material on each screen enabled that only one-layer of spheres has been screened until constant amount of retained spheres (zero throuput), which resulted into ample sieving time.

The component portions have been obtained on a high precision rotational sample splitter using the slowest possible samples' flow. The high statistical representativity of each split was confirmed by the negligible variation of the weight of each component split. Still, each sample had a specific percentage of the three components, and, this way, has been produced exclusively for each participant.

The percentages of each three sieve fractions of the Sand 1 are shown in the Table below, column headed by "14" for the Participant 14 (Syvitski's code "ST3"), who analyzed the sub-sample [split] 4, = "14S1S4") by the MacroGranometer. This sub-sample had a mean density 2.487125 g/cm3.

For comparison, three sieve fraction percentages of the Sand 1 are shown in the same Table, column headed by "7" for the Participant 7, who analyzed the sub-sample 2 by a carefully executed sieving at 0.25 PHI.

Participant-# 14 7
# PHI-mean mm g/cm3 % %
1 0.515±0.010 0.700±0.005 2.5050 25.3 26.0
2 1.000±0.015 0.500±0.005 2.5035 20.7 20.6
3 1.498±0.020 0.354±0.005 2.4700 54.0 53.4

The MacroGranometer™ analysis by the participant 14 of the same sample, and decomposed by our program Shape™ have recovered the original three distribution components very closely:

# PHI-mean mm-mean

PHI-standard deviation



 0.667 0.0698 22.39
2 0.8733  0.546 0.0842 26.99
3 1.4926  0.355 0.1053 50.63

Below are the graphical plots of the MacroGranometer™ analysis (participant 14, sand 1, sub-sample 4 = 14S1S4.dat):

Example of an analysis processed by SedVar into frequency and cumulative  curves
(the frequencies are plot in linear scales).
The sample 14S1S4 was a calibration material consisting of glass spheres, participant 14 ("ST3"), sand 1, sub-sample (split) 4.

Example of an analysis processed by SedVar into cumulative curve
(the cumulative frequency is in probability scale).
The same sample as above.

Below is the graphical output of our SHAPE™ program (produced by MS EXCEL program):

Below is the result of standard sieving (at 0.25 PHI intervals) by the participant 7.


The histogram above suffers from three fundamental shortcomings of the sieving (at 0.25 PHI) in comparison with a sedimentation method (at 0.02 PHI):

  1. The sieving, using 12.5-times wider intervals than the MacroGranometer™, resolves only two instead of three components. The third component can only be suspected according to the asymmetry of the smaller distribution component.
  2. The sieving is shifting the results by its interval width (0.25 PHI = 1/8 of the grain size) toward finer grain size.
  3. Nonspherical particle shape affects the sieving size inconsistently with specific surface: particles with nonspherical shape are sieved as coarser, whereas their specific surface is greater as that of the finer particles.

Please note that Syvitski has not:

  1. exactly known the size distributions of the test samples synthesized by J. Brezina, therefore his evaluations could not be appropriate;

  2. identified the mixed distribution components by a program such as our Shape™.

Five types of settling tubes provided clearly better results than all other tested instruments (image analyzer, Coulter-Counter™, Malvern™ laser particle sizer, SediGraph™, photosedimentometer Lumosed™).

From the five settling tubes, three ones (two of them were MacroGranometers™) qualified as Advanced Settling Tubes. The output of both MacroGranometers™ best matched the expected results using the above shown highly demanding criteria (fit of the mixed distribution components).

The other settling tubes, and particularly other instruments, could even not reproduce the original fractions. The component modes were so strongly shifted that they could hardly be recognized as formed by the original fractions; frequently, additional modes formed or some of the modes disappeared.

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