GB1597533A - Method of and apparatus for measuring physical or chemical properties of flowable materials - Google Patents
Method of and apparatus for measuring physical or chemical properties of flowable materials Download PDFInfo
- Publication number
- GB1597533A GB1597533A GB7635/78A GB763578A GB1597533A GB 1597533 A GB1597533 A GB 1597533A GB 7635/78 A GB7635/78 A GB 7635/78A GB 763578 A GB763578 A GB 763578A GB 1597533 A GB1597533 A GB 1597533A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sampling vessel
- measuring
- stream
- sand
- vessel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000463 material Substances 0.000 title claims description 106
- 238000000034 method Methods 0.000 title claims description 19
- 230000009969 flowable effect Effects 0.000 title claims description 15
- 239000000126 substance Substances 0.000 title claims description 13
- 238000005070 sampling Methods 0.000 claims description 54
- 239000004576 sand Substances 0.000 claims description 39
- 239000000523 sample Substances 0.000 claims description 25
- 238000005259 measurement Methods 0.000 claims description 14
- 238000002156 mixing Methods 0.000 claims description 13
- 238000005303 weighing Methods 0.000 claims description 11
- 238000011068 loading method Methods 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000003860 storage Methods 0.000 claims description 7
- 238000007599 discharging Methods 0.000 claims description 5
- 238000009434 installation Methods 0.000 claims description 5
- 238000011049 filling Methods 0.000 claims description 4
- 238000009826 distribution Methods 0.000 claims description 3
- 239000011230 binding agent Substances 0.000 claims description 2
- 238000000280 densification Methods 0.000 claims description 2
- 238000003780 insertion Methods 0.000 claims description 2
- 230000037431 insertion Effects 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 4
- 239000004568 cement Substances 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Hydrology & Water Resources (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Sampling And Sample Adjustment (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Description
(54) METHOD OF AND APPARATUS FOR MEASURING
PHYSICAL OR CHEMICAL PROPERTIES
OF FLOWABLE MATERIALS
(71) We, ELBA-WERK MASCHINEN
GESELLSCHAFT mbH & Co., a German
Company, of 7505 Ettlingen/Baden,
Bahnhofstrasse 17-1 9, Federal Republic of
Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method of and apparatus for measuring physical or chemical properties of flowable materials, in particular the inherent humidity of flowable materials, for example for the preparation of concrete, the preparation of moulding sand, for the glass industry, and for the chemical and food industries.
Whenever flowable materials are mixed together from different components, there exists the problem of obtaining a certain uniform quality for the final mixture. This applies in particular to the preparation of concrete. In this case the mixing quality, particularly in respect of the final strength and the ease of manipulation (consistency), must be kept constant for a multitude of mixtures, often over long periods of time, in order that even the largest concreting sections of a building structure may be produced without defects.
In addition to the accurate metering of the individual mixture components and observations of the correct mixing period, the quantity proportion of mixing water and cement, in short referred to as WZ factor, is decisive for the final strength of the concrete.
The greatest uncertainty in maintaining the necessary WZ factor results from the fluctuating inherent humidity of the component substances, in particular sand with its low grain fraction of from 02 mm. Depending upon its extraction and preparation, the sand is delivered to the consumer with a highly variable moisture content. Transport is effected mostly in open vehicles. At the location of use, the sand is then deposited on storage dumps or in open or closed storage silos. On the storage dumps and in the open silos the sand is continuously exposed to the influence of the weather, and quite considerable differences in its inherent moisture result from the transport as well as the storage at the location of use.Different values between 1% and 15%, measured at the sand weight of each mixed charge, have been found, i.e. the quantity of water contained in a mixture with for example a 1,000 kg sand proportion, as well as the quantity of sand, have shown a variation of over 140 kg (litres), without regard to the water contained in the sand as inherent moisture.
However, since even small variations in the sand humidity influence the quality and consistency of the concrete, the inherent moisture in the sand must always be determined and taken into account for metering the mixing water as well as the sand proportion.
Numerous measuring methods and measuring apparatuses have already been proposed for this purpose. However, in all these known methods and apparatuses difficulties arise from time consuming manipulations, which thereby reduce the efficiency of the concrete preparation installation in an unacceptable manner, or from measuring uncertainties which result in particular from uncontrollable changes in the physical and chemical properties of sand and water influencing the measuring apparatus.
Therefore the problems connected with the measurement of said moisture are generally known and have been dealt with previously in the following investigations:
I. Frenking, H., Dr.-Ing., TU-Aachen: "Grenzen und Möglichkeiten von elektrischen Geräten bei der Eigenfeuchtigkeitsbestimmung von Zuschlagen". Special edition "Die Bauwirtschaft", 1969, Volume 1 of 4.1.
1969.
2. Lick, W.. Dr.-Ing., Karlsruhe, 1971: "Die Wassergehaltsmessung von Sanden und Kalksandmischungen".
3. Slowack, W., Dr.-lng., Dissertation at the TU-Aachen, 1972: "Grenzen der Feuchtigkeitsmessung von Zuschlagen fiir die
Betonherstellung".
Nevertheless the measuring methods nowadays usable in practice for the measurement of sand moisture in concrete preparation installations are not accurate enough because of the interfering quantities influencing the measurement.
The variation of quality and consistency resulting from the inaccurately detected variable water proportion however, constitutes a safety risk which must be compensated for partly by a cost-intensive increase in the cement proportion and by increased dimensioning of the construction components, which is expensive.
The non-observance of the WZ factor and the consistency of the concrete leads in concrete structures to expensive and under certain circumstances environment-polluting waste production.
Admittedly in a few cases good results were obtained by means of nuclear moisture measurement based on the deceleration of fast neutrons by hydrogen atoms, but the nuclear measurement does not import the necessary accuracy in all cases, in particular in the star-shaped component material stores widely used in concrete preparation installations.
Moreover, the employment of this method is rendered difficult by the extremely high investment costs. Since the fluctuations in the material density occurring in practice also influence the nuclear measurements, this influence must be compensated for, frequently afterwards, by a density compensation. Thereby the investment costs are again increased quite considerably.
Also the calibration of the nuclear measuring device is extremely difficult and time consuming and special safety measures must be taken for handling the radio-active probe and radiation protection rules must be observed.
In contrast thereto, dielectric moisture measuring devices which are based on the measurement of the dielectric constants in conjunction with high-frequency damping are acceptable from the point of view of cost and are well suited for the measurement of the sand moisture. according to an investigation report of the TU-Clausthal. published in "Tonindustriezeitung" of 20th April 1972.
However, in practice considerable mismeasurements result even in this case owing to different material density in the active region of the material store as well as from different pressure loading of the measuring probe.
Moreover, because of the small measuring volume of the measuring probe only a small fraction of the material charge to be removed from the material store is treated. Therefore, in view of the usual different moisture distribution in the active region of the material store the mean moisture value, which alone is of interest, of the material charge cannot be determined.
In many cases even the introduction of measuring probes into the active region of the storage location provides difficulties, because the measuring probe can be built into only one position in the material store in many cases; at least intermittently no exchange of material takes place at these positions, so that the moisture of the next material charge is not measured, but that of the material remaining in the material store.
In addition, the moisture measurement is frequently falsified by material adhering in the region of the measuring probe.
The present invention provides a method of measuring physical or chemical properties of flowable materials, comprising, for each measuring operation, diverting a quantatively constant part of a stream of material flowing out of a material store into a sampling vessel separate from the material store, bringing the material to a uniform density by means of a vibrator built into the sampling vessel, and, after the flow of material from the material store has ceased, measuring the properties of the material by means of a measuring probe at continuously constant pressure loading, and subsequently emptying the material from the sampling vessel into a weighing container after the measuring operation.
The properties measured are preferably at least one of moisture, temperature and pH value.
Thus the measuring does not take place at only one location in the material store at which the measuring probe would otherwise be located and at which quite different measuring quantities may exist than in the portion of the stream of flowable material which is withdrawn from the material store, but the measurement according to the invention is taken on an actual cross-section from the material charge flowing out at that instant.
The invention in another aspect provides apparatus for carrying out the method according to the first aspect of the invention, comprising a sampling vessel separate from a material store, into which sampling vessel may be diverted a part of a stream of material flowing out of the material store, a vibrator built into the sampling vessel for bringing the material to a uniform density, a measuring probe for measuring the properties of the material, and a weighing container arranged to receive material emptied from the sampling vessel.
For the purpose of intercepting a part of the stream of material flowing out of the material store, the sampling vessel may be pivotable into the material stream and back again for discharging by means of a drive.
Alternatively, the sampling vessel may be arranged to be stationary and to extend into the material stream by its forward interceptor portion, the sampling vessel being provided with a separate discharge opening.
Guide plates or feed devices may be provided in the material store outlet for the constant uniform filling of the sampling vessel.
For improving the homogeneity of the material sample, a mixing mechanism may be built into the sampling vessel, if this is necessary because of the material structure.
The main advantage of the present invention is that all factors have been removed which heretofore falsified every measuring result, that is the measuring probe is arranged at a location at which no movement of material takes place, but at which considerable fluctuations of density and pressure may prevail, and each measurement detects the actual cross-section of a charge, the measurement being always effected at a constant pressure loading of the measuring probe, and the sampling vessel being easily attachable, even at a later date, to any existing metering installation.
The invention will be further described, by way of example only, with reference to the accompanying drawing, which shows apparatus for measuring physical or chemical properties of flowable materials.
With reference to the drawing, the sand required for composing each mixed material charge is located in a material storage bunker
I and after opening of a closure 2 travels in the form of a sand stream 4 through an outlet 3 into a weighing container 5 into which are also delivered the further component materials, and in which container 5 the various components are weighed for the total charge.
Because of the special significance of the inherent moisture contained in the sand, a sampling vessel 6 is so arranged at the outlet 3 that its forward interceptor portion 60 projects slightly into the sand stream 4 and receives in it a partial sand stream 40. Thus a representative partial sand stream 40 from the sand stream 4 is withdrawn for each mixed material charge and is introduced into the sampling vessel 6.
A vibrator 7 is built into the sampling vessel 6 to bring the inflowing partial sand stream 40 to a continuously constant density value and thereby provide the necessary condition for a uniform measuring state.
A measuring probe 8 projects into the sampling vessel 6, and the actual mean moisture value of the entire sand quantity passed in to the weighing container 5 is thereby detected by a dielectric or other known manner. The measuring result is then taken into account when determining the mixing water quantity which must still be added to the total charge of the component materials during the mixing process after the admixture of a binding agent.
The sampling vessel 6 is so attached to a holder 9 and an adjuster plate 10 by means of elongate holes 11 and bores 12 that its interceptor portion 60 can be adjusted for receiving a partial sand stream 40 which flows for as long as the sand stream 4.
A cylinder and piston unit 13 is pivotally connected on the one hand to the adjuster plate 10 and on the other hand to the sampling vessel 6, in order to discharge the contents of the latter into the weighing container 5 after the measuring process is terminated, and subsequently to return the vessel 6 to its filling position. The discharge is assisted by the vibrator 7.
In a simplified constructional form of the measuring apparatus the cylinder and piston unit 13 may be omitted and the sampling vessel 6 may be rigidly attached to the adjuster plate 10. For discharging the contents of the sampling vessel 6 the latter then has a discharge opening at its lower end.
Guide plates or any other desired feed devices may be arranged in the outlet 3 for guiding the partial sand stream 40.
Furthermore, a mixing mechanism may be build into the sampling vessel 6 for homogenising the material sample.
In any case, the insertion of a crosssectional portion of the flowable material which is being metered, the uniform volume capacity of the sampling vessel, and the always constant densification by means .of the vibrator lead to a continuously constant pressure loading of the measuring probe and to the obtaining of accurate measuring results even when the moisture distribution in the overflowing material exhibits large differences.
WHAT WE CLAIM IS:
1. A method of measuring physical or chemical properties of flowable materials, comprising, for each measuring operation, diverting a quantatively constant part of a stream of material flowing out of a material store into a sampling vessel separate from the material store, bringing the material to a uniform density by means of a vibrator built into the sampling vessel, and, after the flow of material from the material store has ceased, measuring the properties of the material by means of a measuring probe at continuously constant pressure loading, and subsequently emptying the material from the sampling vessel into a weighing container after the measuring operation.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
1. A method of measuring physical or chemical properties of flowable materials, comprising, for each measuring operation, diverting a quantatively constant part of a stream of material flowing out of a material store into a sampling vessel separate from the material store, bringing the material to a uniform density by means of a vibrator built into the sampling vessel, and, after the flow of material from the material store has ceased, measuring the properties of the material by means of a measuring probe at continuously constant pressure loading, and subsequently emptying the material from the sampling vessel into a weighing container after the measuring operation.
2. A method as claimed in Claim I,
wherein the properties measured are at least one of moisture, temperature and pH value.
3. A method of measuring physical or chemical properties of flowable materials, substantially as herein described with reference to the accompanying drawing.
4. Apparatus for carrying out the method as claimed in Claim 1, comprising a sampling vessel separate from a material store, into which sampling vessel may be diverted a part of a stream of material flowing out of the material store, a vibrator built into the sampling vessel for bringing the material to a uniform density. a measuring probe for measuring the properties of the material, and a weighing container arranged to receive material emptied from the sampling vessel.
5. Apparatus as claimed in Claim 4, wherein, for the purpose of intercepting a part of the stream of material flowing out of the material store, the sampling vessel is pivotable into the material stream and back again for discharging by means of a drive.
6. Apparatus as claimed in Claim 4, wherein, for the purpose of intercepting a part of the stream of material flowing out of the material store, the sampling vessel is arranged to be stationary and to extend into the material stream by its forward interceptor portion. the sampling vessel being provided with a separate discharge opening.
7. Apparatus as claimed in any of Claims 4 to 6, wherein guide plates or feed devices are provided in the material store outlet.
8. Apparatus as claimed in any of Claims 4 to 7, wherein a mixing mechanism is built into the sampling vessel for homogenizing the material sample.
9. Apparatus for measuring physical or chemical properties of flowable materials, substantially as herein described with reference to, and as shown in, the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2708943A DE2708943C2 (en) | 1977-03-02 | 1977-03-02 | Method for measuring the inherent moisture content of bulk materials during concrete preparation and device for carrying out the method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1597533A true GB1597533A (en) | 1981-09-09 |
Family
ID=6002530
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7635/78A Expired GB1597533A (en) | 1977-03-02 | 1978-02-27 | Method of and apparatus for measuring physical or chemical properties of flowable materials |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS53109693A (en) |
| DE (1) | DE2708943C2 (en) |
| ES (1) | ES467459A1 (en) |
| FR (1) | FR2382686A1 (en) |
| GB (1) | GB1597533A (en) |
| IT (1) | IT1102713B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS636675Y2 (en) * | 1979-04-26 | 1988-02-25 | ||
| DE3538885C1 (en) * | 1985-11-02 | 1987-06-04 | Elba Werk Maschinen Gmbh & Co | Method and appliance for measuring the intrinsic moisture of bulk solids in the preparation of concrete |
| DE3612282C3 (en) * | 1986-03-13 | 1993-12-23 | Liebherr Mischtechnik Gmbh | Device for measuring the moisture of bulk materials in the flowing material flow |
| SE500831C2 (en) * | 1992-03-13 | 1994-09-12 | Ingemar Dahl | Device and method for moisture measurement during concrete manufacture |
| DE19512924C2 (en) * | 1995-03-30 | 1997-07-03 | Elba Werk Maschinen Gmbh & Co | Device for measuring the intrinsic moisture of the components of a building material mixture |
| CN102505857B (en) * | 2011-11-18 | 2014-02-19 | 河海大学 | Method for positioning vibrating trace of vibrating needle in concrete based on GPS (Global Positioning System) |
| CN102444289B (en) * | 2011-11-18 | 2013-09-25 | 河海大学 | Concrete pouring and vibrating dynamic visualization monitoring method |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE7414019U (en) * | 1974-10-17 | Polysius Ag | Device for taking samples from a stream of granular or small-sized material | |
| DE899618C (en) * | 1941-10-17 | 1953-12-14 | Hans Lange Dr Ing | Arrangement for the automatic regulation of the addition of water according to the inherent humidity of the aggregate during the concrete preparation |
| AT205900B (en) * | 1958-09-23 | 1959-10-26 | Josef Dipl Ing Daum | Process for the production of concrete mixes |
| DE1498590B1 (en) * | 1963-10-31 | 1970-09-03 | Brinkmann Ag M | Automatic device for determining the humidity of a fibrous or sheet-like material |
| AT262126B (en) * | 1965-06-28 | 1968-05-27 | Ammann U Maschf Ag | Process for the batch production of fresh concrete and equipment for carrying out the process |
| US3614230A (en) * | 1969-05-08 | 1971-10-19 | Exxon Research Engineering Co | Apparatus and method for sampling and analyzing fluid solids |
| US3575055A (en) * | 1969-10-16 | 1971-04-13 | Continental Carbon Co | Apparatus for automatically sampling solids |
| CH568139A5 (en) * | 1973-08-30 | 1975-10-31 | Ammann U Maschinenfabrik Ag | |
| FR2258253B1 (en) * | 1974-01-21 | 1978-03-17 | Lerebourg Michel | |
| DE2417012A1 (en) * | 1974-04-08 | 1975-10-23 | Scheurich | Concrete mixes from cement, aggregates and water - using memory stores to calculate exact amt. of water required |
-
1977
- 1977-03-02 DE DE2708943A patent/DE2708943C2/en not_active Expired
-
1978
- 1978-02-21 FR FR7804855A patent/FR2382686A1/en active Granted
- 1978-02-27 GB GB7635/78A patent/GB1597533A/en not_active Expired
- 1978-03-01 ES ES467459A patent/ES467459A1/en not_active Expired
- 1978-03-01 IT IT48246/78A patent/IT1102713B/en active
- 1978-03-02 JP JP2286978A patent/JPS53109693A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2382686B1 (en) | 1984-02-10 |
| IT1102713B (en) | 1985-10-07 |
| JPS6225987B2 (en) | 1987-06-05 |
| JPS53109693A (en) | 1978-09-25 |
| DE2708943C2 (en) | 1986-09-11 |
| DE2708943A1 (en) | 1978-09-07 |
| ES467459A1 (en) | 1979-07-01 |
| IT7848246A0 (en) | 1978-03-01 |
| FR2382686A1 (en) | 1978-09-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |