FR2828415A1 - Manufacture of hydraulic, hydrocarbon or bituminous compounds from a mixture of water and various granulates, whereby composition is closely controlled by measuring both the weight of added product and its moisture content - Google Patents

Abstract

Method for management of a continuous fabrication installation for mixing water with different granulates, with each granulate distributed by a hopper equipped with an extractor that deposes its product onto a conveyor belt from where it is transported into a mixer. Accordingly the method involves measurement of conveyor belt speed and thus material flow for each granulate, with at the same time continuous measurement of the moisture level in each granulate at least one position upstream of the mixer. An Independent claim is made for a manufacturing installation for producing of water and granulate mixtures for used in binding compounds.

Description

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 The invention relates to an installation for mixing aggregates and a method for managing the installation.

 The prior art already knows various variants of aggregates mixing installations. An installation of this type makes it possible to prepare hydraulic or hydrocarbon or bituminous binders by mixing water and various aggregates or constituents in variable percentage.

 Each of the aggregates is, for example, distributed by a hopper fitted at the bottom with an extractor depositing the aggregate on a conveyor belt which pours the products into a mixer.

 It is already known to automatically manage the entire installation by means of a computer as a function of the speed of the strip and / or flow rate of each of the aggregates. These data are, for example, continuously measured by a speed sensor and / or an integrating rocker placed on the belt, and the computer acts, for example, on the motor-reducer driving the belt and on the speed variator of the extractor motor, the installation possibly comprising a double strip.

The user has an anological or digital control panel allowing him to enter one or more set values in the computer
Currently, it is not known to automatically manage an installation of this type as a function of the humidity level of one or more of the constituents, nor as a function of the humidity level of the final product.

 This would indeed require specific means to continuously measure this moisture content in a flow of abrasive material in permanent motion.

 The means currently used to measure the humidity on these installations are means of measurement by sampling. The operator therefore only has specific information on this data and it is impossible to program a recipe which would allow a predefined mixture to be produced continuously and reliably, the uncertainty on the humidity level being very variable.

 However, in the state of the art, there are a few means of continuous humidity measurement, but they have numerous drawbacks, which prevents them from being installed on a production installation.

 They present in particular the following drawbacks: - delicate installation and assembly, - doubtful reliability, in some cases, use of isotopes (regulatory constraints and difficult linearization of results)

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 in any case, high cost.

 The object of the present invention is to provide a method capable of managing an installation of the type described above, continuously as a function of one or more humidity rate values measured continuously at one or more points located in the flow. of material.

 This object is achieved by the invention which consists of a method for managing a continuous manufacturing installation of a mixture of water and various aggregates, each of the aggregates being distributed by a hopper equipped at the bottom with an extractor depositing the granulate on a conveyor belt discharging the products into a mixer, process capable of continuously measuring the speed of each conveyor belt and continuously measuring the flow rate of each aggregate, characterized in that it is capable of measuring in continuous humidity at at least one point in the path of the material.

 The humidity can be measured upstream and / or downstream of the mixer.

 According to a variant, the method is able to calculate the dry flow of aggregate for each hopper.

 According to another variant, the method is capable of programming and regulating the installation as a function of the dry flow rates on each of the hoppers, a dry flow rate instruction being added to the measurement of the humidity level of the corresponding hopper.

 According to another variant, the humidity measurement is compared with a humidity instruction set in advance in a comparator, the difference between the measurement and the instruction representing the correction to be made, then the correction value is compared in a comparator to the actual measurement of the water flow, and the comparator output information acts on a speed controller of the supply means in order to regulate the water flow continuously, as a function of the continuous measurement of the humidity level.

 According to another variant, it allows the management of an installation comprising several treatment lines and:

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 the measurements of the humidity levels measured upstream of each mixer of each treatment line are entered into a calculation block which performs a weight average, taking into account the flow rate of each hopper and the percentage of water of each component.

The result or average is compared to a humidity setpoint
At the same time, the humidity measurement at the mixer outlet is also compared with the same humidity setpoint.
The values of the comparator outputs are compared with each other
The result of the comparison of the previous values is compared with the actual measurement of the water flow.

 Optionally, provision can also be made for continuous measurement of the temperature of the materials (aggregate or final product).

 The invention also relates to a computer designed for carrying out the method of the invention.

 The invention also relates to an installation for continuously manufacturing a mixture of water and various aggregates and binders, each of the components and aggregates being distributed by a hopper fitted at the bottom with an extractor depositing the aggregate on a conveyor belt which pours the products into a mixer, characterized in that it comprises at least one humidity rate sensor capable of continuously measuring said moisture content of the material at a point in its path.

 To do this, such a humidity level sensor can be placed upstream and / or downstream of the mixer of the installation.

 The invention will be better understood using the description below of several non-limiting embodiments of the invention, made with reference to the following appended figures: FIG. 1: block diagram of an installation comprising a regulation in function of the humidity level measured continuously before each mixer, FIG. 2: schematic diagram of an installation comprising regulation as a function of the humidity level measured continuously at the outlet of one or each mixer,

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 FIG. 3: schematic diagram of an installation comprising regulation as a function of the humidity rate measured continuously before and after the mixer, FIG. 4: diagram of connection of the general computer of the installation.

 Reference is now made to FIG. 1 to describe a first variant of implementation of the invention.

 As an example, FIG. 3 shows three hoppers, but this number is not limiting.

 According to a first example of operating mode, measurements of the total dry flow can be obtained.

 Conventionally, each hopper (la, lb, lc) is equipped in the lower part with an extractor depositing the aggregate on a conveyor belt (2a, 2b, 2c).

 Each extractor is equipped with an integrating flip-flop on tape which captures the flow coming and the speed of the belt and generates a measurement signal of aggregate flow coming on time (3a, 3b, 3c) according to the information of weight (5a, 5b, 5c) and speed (6a, 6b, 6c). Each aggregate flow measurement signal is sent to the inputs of a computer (7).

 The treatment line of each hopper (1 a, 1 b, 1 c) is equipped with a means of continuous measurement of the humidity level located upstream of the mixer (for example upstream of the extractor) and generating each a humidity measurement signal (4a, 4b, 4c), sent to the input of said computer (7).

 For each hopper, the calculator is able to calculate the dry flow (8a, 8b, 8c) of aggregate in tonnes per hour by difference and to display it on a display (9).

 The dry flow can be a unit flow (8a, 8b, 8c) per dispenser or total for the entire installation.

 According to a second example of operating mode, the computer (7) of the installation can be programmed in dry flow.

 For each hopper, an extractor setpoint (10a) (in t / h) of dry flow is added in an operator (11a) to measure the humidity level (4a) of the corresponding hopper. The operator's output (Qa) (11) is therefore the sum of the humidity rate (4a) and the dry flow setpoint (10a). The value (Qa) is used to control the speed variation of the extractor of the first hopper and is given by the formula Q (work) = Qsec / 1- (% water).

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 The same wiring and the same summation in operators (11b, 11c) are used for the other two processing lines but have not been shown in FIG. 1 for the sake of clarity and appear in FIG. 3.

 The set values (10a, 10b, 10c) for the hoppers can be identical or different depending on the recipe that the user wants to program according to the dry flow rates on each of the hoppers, therefore according to the components of the mixture to be obtained. The corrections of proportions are carried out automatically by the computer (7).

 Reference is now made to FIG. 2 to describe a second variant of implementation of the invention.

 For the sake of clarity, a single processing line has been shown, but the installation may include several, for example three as in the first figure.

 The measurement is carried out continuously at a point (20) of the path of the material leaving a mixer (21).

 For the reliability of the measurements it is important to choose a point (20), for example in a chute or a slide (where one is certain that there never occurs clogging or accumulation of product) or else on the vein of product transported by the strip (22) or else in contact with the lower strand of the strip.

 The sensor used can be of any known type (dielectric, etc.) and can be a contact sensor or a contactless sensor (with infrared for example).

 In the case of a contact sensor, it is necessary to adapt it specially so that it resists abrasion, for example by covering it with an anti-abrasion layer (ceramic layer for example).

 The humidity measurement (23) (for example 10%) is compared with a humidity setpoint (24) fixed in advance (for example 15%) in a comparator (25).

 The difference, for example 5%, between the measurement (23) and the setpoint (24) represents the correction (26) to be made.

 The value of the correction (26) is compared in a comparator (28) to the actual measurement (27) of the water flow, measurement carried out by a flow meter at the outlet of the water supply means, in the figure a set ( regulated valve 29 and pump 30).

 The output information (31) of the comparator (28) acts on a variable speed drive (32) of the water supply means (29, 30) in order to continuously regulate the

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 water flow (33) injected into the treatment line upstream of the mixer, as a function of the continuous measurement of the humidity level (23).

 The advantage of this alternative embodiment is to be able to guarantee the percentage of humidity in the mixture from a recipe, that is to say from a predefined composition.

 Referring now to Figure 3 which shows a third variant of implementation of the invention.

 According to this variant, the installation is regulated taking into account the measurement of the moisture content of the material both upstream and downstream of the mixer of each treatment line.

 We find in Figure 3 the elements referenced 1 to 11 in Figure 1.

 The installation comprises in this example, three hoppers (la, lb, lc) and three processing lines which are not all entirely drawn for the sake of clarity and which each operates as previously described.

 The humidity rate measurements (4a, 4b, 4c) are entered into a calculation block (40) which performs a weight average, taking into account the flow rate of each hopper and the percentage of water in each component.

 The result or average (41) is compared with a humidity setpoint (42) in a first comparator (43).

 In parallel, the humidity measurement (23) (see also Figure 2) at the mixer outlet is also compared to the same humidity setpoint (42) in a second comparator (44).

 The values of the outputs (E) and (R) of the comparators 43 and 44 are compared with one another in a third comparator (45).

 The output result (46) of the third comparator (45) is compared by the fourth comparator (28) (as in FIG. 2) with the actual measurement (27) of the water flow which is regulated in the same way as in figure 2.

 The computers and comparators listed above are functional blocks of a general computer contained in a housing (60) shown in FIG. 4.

 In the figure, it receives, without limitation, the speed and weight information (from 0 to 10 V and from 4 to 20m A) on each line 1, line 2, line 3 and on the mixer, as well as the flow rate (Q in t / h) dosers on each of these lines and on the mixer, and gives the dry flow rates on the line and mixer.

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 This general computer can be equipped with one or more alarm outputs (for example an alarm for lack of flow on a line), a connection line (63) for a programming console, an Authorization key -Market .

 It can manage, by way of nonlimiting example, 2 to 8 humidity probes (or sensors) arranged at predetermined points in the path of the aggregates, these being particularly studied to be able to withstand a very hard working environment.

 The main advantage of the process according to the invention is to carry out an exact metering of the materials (in dry weight), since it makes it possible to determine the percentage of water contained in the aggregates (all coming), the recipe for the desired mixture being directly entry into the automation of the general computer, according to the percentage of water, which controls the extractor to obtain exact quantities of product to be discharged from each hopper.

 In addition, a measurement of the humidity is carried out on each aggregate outlet. This measurement is carried out continuously and makes it possible to constantly know the evolution of the humidity rate, the measurements being used in the general computer.

 The process or the installation according to the invention can be adapted according to the desired application because: - the aggregates are stored in hoppers with variable capacities according to the characteristics (sizes and nature), - the number of hoppers and treatment lines are not limited, - the materials can be extracted from the hoppers by different means; belt extractors, vibrating extractors, rotary distributors, etc.

 - the dosing technique used can be: continuous weighing and dosing on a tape (dosometer) weighing and dosing in weight loss,. dosing by controlled opening of a hopper, it is possible to add means for continuously measuring the average temperature of each of the aggregates and / or of the final product. In this case it is possible to associate with each humidity measurement point a measurement of

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 temperature. The temperature measurement to weigh the water additions (example, in the case of high heat, correct the water intake taking into account greater evaporation).

 The method according to the invention and the associated general computer operate on any new installation.

 However, it is also possible to apply the method according to the invention to an already existing manufacturing installation, the general computer being provided so that it can be integrated into an existing automation.

 In addition, provision can be made to trigger the correction if the correction lE-RI is greater than a predetermined value, for example 1.5% (the correction will therefore be weighted).

Claims (23)

 CLAIMS 1. Method for the management of a continuous manufacturing installation of a mixture of water and various aggregates, each of the aggregates being distributed by a hopper equipped at the bottom with an extractor depositing the aggregate on a conveyor belt pouring the products into a mixer, process capable of continuously measuring the speed of each conveyor belt and continuously measuring the flow rate of each aggregate, characterized in that it is capable of continuously measuring the moisture content in at least a point in the path of the material. 2. Method according to claim 1, characterized in that the humidity is measured at a point on the path located upstream of the mixer. 3. Method according to claim 1, characterized in that the humidity is measured at a point in the path located downstream of the mixer. 4. Method according to claim 1, characterized in that the humidity is measured upstream and downstream of the mixer. 5. Method according to claim 2, characterized in that it is able to calculate the dry aggregate flow (8a, 8b, 8c) for each hopper. 6. Method according to claim 5, characterized in that it is capable of programming and regulating the installation as a function of the dry flow rates on each of the hoppers, a dry flow rate instruction being added to the measurement of the humidity rate of the corresponding hopper. 7. Method according to claim 6, characterized in that the set values for the hoppers can be identical or different according to the recipe which one wants to program according to the components of the mixture to be obtained. 8. Method according to claim 7, characterized in that the corrections of proportions are carried out automatically. 9. Method according to one of claims 1 to 8 characterized in that it is capable of continuously measuring the average temperature of the materials. 10. Method according to claim 3, characterized in that the humidity measurement (23) is compared with a humidity setpoint (24) fixed in advance in a comparator (25), the difference between the measurement and the instruction representing the correction to be made. <Desc / Clms Page number 10> 11. Method according to claim 10, characterized in that the correction value (26) is compared in a comparator (28) to the actual measurement (27) of the water flow. 12. Method according to claim 11, characterized in that the output information (31) of the comparator (28) acts on a variable speed drive (32) of the supply means (29,30) in order to regulate the flow d water (33) continuously, according to the continuous measurement of the humidity level (23). 13. Method according to claim 4, characterized in that it allows the management of an installation comprising several treatment lines and in that: - the measurements of the humidity levels (4a, 4b, 4c) measured upstream of each mixer of each treatment line is entered into a calculation block (40) which performs a weight average, taking into account the flow rate of each hopper and the percentage of water of each component. The result of the comparison of the values (E) and (R) above is compared with the actual measurement of the water flow.  The result or average (41) is compared to a humidity setpoint (42) - At the same time the humidity measurement (23) at the mixer outlet is also compared to the same humidity setpoint (42) - The values of the outputs (E) and (R) comparators (43) and (44) are compared with each other 14. Computer, characterized in that it is designed for the implementation of the method according to one of claims 1 to 13. 15. Computer according to claim 14, characterized in that it comprises one or more alarm outputs. 16. Computer according to one of claims 14 to 15, characterized in that it comprises a connection line for a programming console. 17. Installation for continuously manufacturing a mixture of water and various aggregates and binders, each of the components and aggregates being distributed by a hopper equipped at the bottom with an extractor depositing the aggregate on a conveyor belt which discharges the products in a mixer, characterized in that it comprises <Desc / Clms Page number 11>  at least one humidity rate sensor capable of continuously measuring said moisture content of the material at a point in its path. 18. Installation according to claim 17, characterized in that it comprises at least one sensor placed upstream of the mixer. 19. Installation according to claim 17, characterized in that it comprises at least one sensor placed downstream of the mixer. 20. Installation according to claim 17 characterized in that it comprises at least one sensor placed upstream and at least one sensor placed downstream of the mixer. 21. Installation according to claim 19, characterized in that each sensor is placed in a chute or a slide (where it is certain that there is never clogging or accumulation of product) or on the vein of product transported by the strip (22) or else in contact with the lower strand of the strip. 22. Installation according to claim 21, characterized in that the sensor is a contact sensor specially adapted to resist abrasion, by covering a ceramic layer. 23. Installation according to one of claims 17 to 21, characterized in that it comprises means for measuring the average temperature of the materials.