Machine-made sand water content on-line detection method and control system

Abstract

According to the online detection method for the water content of the machine-made sand, the correction lambda is introduced into the detection mode, so that the actual water content of the machine-made sand falls into the range of phi n + / -lambda; by overlapping the n intervals A, the interval where the actual water content is located is reduced, and the detection precision of the water content is improved; therefore, the water content detection precision is improved while the detection efficiency is improved, and the situation that the efficiency and the precision cannot be guaranteed at the same time during previous detection is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of building material preparation, and particularly relates to an on-line detection method and control system for the water content of machine-made sand. Background Art

[0002] As one of the physical properties of machine-made sand materials, the water content is a physical quantity for judging whether the machine-made sand meets the factory standard; therefore, in the process of wet sand making, usually when the water content in the machine-made sand is dried to 3% - 5%, it can be sent to the site for use after leaving the factory; therefore, the test of the water content in the machine-made sand before leaving the factory is relatively important.

[0003] Currently, when on-line water content detection is required during the production process of machine-made sand, it is all detected manually, and the detection methods generally adopt the drying method or the resistance test method; among them, the drying method has a higher detection accuracy and can reach ±0.1%, and at this time, it can be regarded as the actual water content of the machine-made sand, but the detection efficiency of the drying method is relatively low, and it takes at least 1 hour for each detection; while the resistance test method has a very high detection efficiency, but the detection accuracy is relatively low and can only reach ±0.5%; since the existing detection methods generally select one of these two detection methods for detection; therefore, this detection method cannot meet the requirements of on-line detection of the water content of machine-made sand with high efficiency and high accuracy at the same time. Summary of the Invention

[0004] The purpose of the present invention is to design an on-line detection method for the water content of machine-made sand to solve the problems raised in the background art. To achieve the above purpose, the present invention provides the following detection method: Step 1: Extract a portion of test sand during the drying process of the machine-made sand pile, and then divide the test sand into a portion of dried test sand and several portions of resistance test sand; Step 2: Detect the water content of the dried test sand by the drying method, and detect the water content of several portions of resistance test sand by the resistance test method respectively; let the water content of the dried test sand be α, and the water content of the resistance test sand be β1, β2, β3, β4...β n ; Step 3: Subtract α from β1 to β n respectively and take the absolute value of the result as γ1 to γ n , and remove j differences greater than 0.5% in γ1 to γ n ; Step 4: Let the correction amount λ be the average value of the remaining γ values, that is ; Step 5. When the water content of the manufactured sand pile is dried to near the factory standard, take out the test sand from the manufactured sand pile, divide the test sand into several equal parts, and quickly detect the water content of the several parts of test sand by the resistance test method. Take the test results as Φ1, Φ2... Φ n ; Step 6. Through Φ n ±λ, obtain n value ranges A n =[Φ n -λ, Φ n +λ]. Overlap the value ranges of A1 to A n , select the range with the most overlapping times, and take the midpoint value A 终 of this range. A 终 is the actual water content of the test sand in Step 5.

[0005] Furthermore, a test column is provided on the central axis of the manufactured sand pile, and several humidity sensors are provided on the test column; the humidity sensors are connected to the detection terminal and are used to feedback the humidity inside the manufactured sand pile, so as to facilitate a preliminary judgment of the water content of the manufactured sand pile and further preliminarily judge the factory time of the manufactured sand pile.

[0006] Furthermore, in Step 1 and Step 5, the test sand just taken out from the manufactured sand pile is first filtered and stirred in a sealed test chamber, and after sufficient filtration and stirring, it is evenly divided. And the surface of the parts in the sealed test chamber that come into contact with the test sand is provided with an anti-scratch hydrophobic layer.

[0007] Furthermore, after the resistance test sand is evenly divided, the loose degree of each portion of the evenly divided resistance test sand is adjusted by gentle pressing to ensure that the loose degree of each portion of the resistance test sand is consistent; at the same time, the loose degree of the resistance test sand after being evenly divided in Step 1 and Step 5 also remains consistent after the gentle pressing adjustment.

[0008] Furthermore, during the drying process of the manufactured sand pile, an experimental test is carried out on the pressing force of the gentle pressing adjustment, and the loose degree of the resistance test sand when the water content is tested by the resistance test method and the test accuracy reaches the highest is selected.

[0009] Furthermore, the method of the experimental test is as follows: take out a portion of test sand from the drying process of the manufactured sand pile, and then divide the test sand into a portion of dried test sand and several portions of resistance test sand. The several portions of resistance test sand reach different loose degrees under the action of different pressing forces; then, the water content of the dried test sand is detected by the drying method, and the water content of the several portions of resistance test sand is detected by the resistance test method respectively. Let the water content of the dried test sand be α', and the water content of the resistance test sand be β1', β2'... β n '; select the β i ' closest to α'; take the detected water content as β iThe looseness of the sand for resistance testing is the standard looseness, and the compaction force at this time is taken as the standard compaction force; The water content of the evenly divided sand for resistance testing in Step 1 and Step 5 is tested only after reaching the standard looseness.

[0010] Furthermore, during the drying process of the manufactured sand pile, the optimal spacing of the probe in the resistance testing method is determined through preliminary experiments. At the same time, when testing the water content of the evenly divided sand for resistance testing in Step 1 and Step 5, the spacing of the probe is the optimal spacing.

[0011] Furthermore, the method of the preliminary experiment is as follows: Take a portion of the sand for testing from the drying process of the manufactured sand pile. Subsequently, divide the sand for testing into a portion of dried sand for testing and several portions of sand for resistance testing. The several portions of sand for resistance testing are placed in a testing tank with probes of different spacings; Subsequently, the water content of the dried sand for testing is detected by the drying method, and the water content of the several portions of sand for resistance testing is detected by the resistance testing method respectively. Let the water content of the dried sand for testing be α'', and the water content of the sand for resistance testing be β1'', β2''...β n ''; Select the β closest to α'' i ''; Detect that the probe spacing of the sand for resistance testing with a water content of β i '' is the optimal spacing; The evenly divided sand for resistance testing in Step 1 and Step 5 is tested for water content under the condition that the probe spacing is the optimal spacing.

[0012] Furthermore, the probe spacing can be set to 10 groups; they are the probe spacing of 5mm, the probe spacing of 5.5mm, the probe spacing of 6mm, the probe spacing of 6.5mm, the probe spacing of 7mm, the probe spacing of 7.5mm, the probe spacing of 8mm, the probe spacing of 8.5mm, the probe spacing of 9mm, the probe spacing of 9.5mm, and the probe spacing of 10mm; and the optimal spacing of the probe is selected through preliminary experiments.

[0013] A control system for the water content of manufactured sand, which is used for the implementation of the on-line detection method of the water content of manufactured sand, includes a control module, a resistance testing module, a drying testing module, and a data transmission module. There is also a calculation module for calculating the correction amount λ inside the control module. Both the resistance testing module and the drying testing module are used to detect the water content of the sand for testing. The data transmission module is used to transmit the water content data detected by the resistance testing module and the drying testing module to the calculation module. There is also a correction detection module connected to the calculation module and used to output A 终 of the control module.

[0014] Compared with the prior art, the beneficial effects of the present invention: In the detection method of the present invention, a correction amount λ is introduced, so that the actual water content in the manufactured sand falls within Φ n ±λ; and through the overlap of n intervals A, the interval where the actual water content is located is narrowed, and the detection accuracy of the water content is improved; therefore, the present invention improves the detection accuracy of the water content while improving the detection efficiency, eliminating the situation where the efficiency and accuracy cannot be guaranteed simultaneously in the previous detection. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of the overall structure of the control system used in the present invention.

[0017] Wherein: 1. Control module; 2. Calculation module; 3. Correction detection module; 4. Resistance test module; 5. Drying test module; 6. Data transmission module. Detailed Embodiment

[0018] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the drawings and preferred embodiments, describe in detail the specific embodiments, structures, features and their effects of the present invention.

[0019] Embodiment: An on-line detection method for the water content of manufactured sand includes the following steps; Step 1: Extract a portion of test sand during the drying process of the manufactured sand pile, and then divide the test sand into a portion of drying test sand and several portions of resistance test sand; Step 2: Detect the water content of the drying test sand by the drying method, and detect the water content of several portions of resistance test sand by the resistance test method respectively; let the water content of the drying test sand be α, and the water content of the resistance test sand be β1, β2, β3, β4...β n ; Step 3: Subtract α from β1 to β n respectively and take the absolute value of the result γ1 to γ n , and remove j differences greater than 0.5% in γ1 to γ n ; among them, since the accuracy of the resistance test method is ±0.5%, a difference greater than 0.5% indicates that there is poor contact or short circuit in the detection process of this portion of resistance test sand, or it is at the end value of the measurement accuracy (with a large error), and it should be discarded to improve the overall detection accuracy of the detection method. Step 4: Set the correction amount λ as the average value of the remaining γ values, i.e., ; Since the β value fluctuates on both sides of the α value, λ will be less than 0.5%. At this time, the value of the correction amount λ is also determined.

[0020] Step 5: When the water content of the manufactured sand pile dries to near the factory standard, take out the test sand from the manufactured sand pile, divide the test sand into several equal parts, and quickly detect the water content of several parts of the test sand by the resistance test method. Take the detection results as Φ1, Φ2... Φ n ; Step 6: Obtain n value ranges A n = [Φ n - λ, Φ n + λ] through Φ n ± λ. Overlap the value ranges of A1 to A n , select the range with the most overlapping times, and take the midpoint value A 终 of this range. A 终 is the actual water content of the test sand in Step 5; among them, the actual water content will fall within the range of Φ n ± λ. Since λ is less than 0.5%, the detection accuracy of the water content is improved. At this time, the detection error of the detection method in the present invention is between the detection errors of the drying method and the resistance test method, and the detection accuracy is higher than that of the resistance test method; and through the overlap of n ranges A, the range where the actual water content is located is further narrowed, and by taking the midpoint value of the range with the most overlapping times as the actual value of the water content, the detection accuracy of the water content is further improved; during the detection process, the resistance test method is adopted, so the present invention improves the detection accuracy of detecting the water content by the resistance test method while improving the detection efficiency, eliminating the situation where the efficiency and accuracy cannot be guaranteed at the same time in the previous detection; in addition, removing the maximum and minimum values in Φ n in Step 5 can reduce the detection error; the present invention determines the correction amount λ during the drying process of the manufactured sand pile, so that the online detection method in the present invention can be directly adopted after drying, thus saving the detection time.

[0021] In the present invention, a test column is provided on the central axis of the manufactured sand pile, and a plurality of humidity sensors are provided on the test column; the humidity sensors are connected to a detection terminal for feeding back the humidity inside the manufactured sand pile, so as to facilitate a preliminary judgment of the water content of the manufactured sand pile, and further a preliminary judgment of the ex-factory time of the manufactured sand pile; it is convenient for testers to measure the manufactured sand in a timely manner; in the above steps 1 and 5, the test sand just taken out from the manufactured sand pile is first filtered and stirred in a sealed test chamber to make the water content of the test sand more uniform while filtering out the impurities in the test sand. After the test sand is fully filtered and stirred, it is evenly divided, and the surface of the parts in the sealed test chamber that come into contact with the test sand is provided with an anti-scratch hydrophobic layer to prevent the moisture inside the manufactured sand from remaining on the stirring mechanism; the detection accuracy is improved.

[0022] Since the contact area between particles of manufactured sand decreases in an overly loose state, more interstitial resistance will be generated in the current path, resulting in a non-uniform electric field; this unstable contact will significantly increase the measurement error, thus affecting the test accuracy of the resistance test method. Therefore, after the resistance test sand in the present invention is evenly divided, the loose degree of each portion of the evenly divided resistance test sand will be gently pressed and adjusted to ensure that the loose degree (degree of looseness) of each portion of the resistance test sand is consistent; at the same time, after the loose degree of the resistance test sand evenly divided in steps 1 and 5 is gently pressed and adjusted, it also remains consistent; thereby improving the test accuracy of the resistance test method; in order to find the most suitable loose degree of the manufactured sand for the resistance test method. Therefore, in the detection method of the present invention, an experimental test of the pressing force of the gentle pressing adjustment will be carried out during the drying process of the manufactured sand pile, so as to select the loose degree of the resistance test sand when the test accuracy reaches the highest when detecting the water content by the resistance test method.

[0023] The specific experimental test method is as follows: Extract a portion of test sand from the drying process of the manufactured sand pile, and then divide the test sand into a portion of dried test sand and several portions of resistance test sand. The several portions of resistance test sand reach different loose degrees under the action of different pressing forces; then the water content of the dried test sand is detected by the drying method, and the water content of the several portions of resistance test sand is detected by the resistance test method respectively. Let the water content of the dried test sand be α', and the water content of the resistance test sand be β1', β2'...β n '; Select the β that is closest to α' i '; Take the detected water content as β iThe looseness of the sand for resistance testing is the standard looseness, and the compaction force at this time is taken as the standard compaction force; thus, during the detection process of the resistance testing method, while the looseness is consistent, the looseness is in the best detection state; it is convenient to improve the detection accuracy; in addition, during the drying process of the manufactured sand pile, multiple portions of the test sand can be extracted for multiple experiments, and the average value is taken to obtain the best standard compaction force and standard looseness; and in steps one and five, the moisture content of the evenly divided resistance test sand is tested only after reaching the standard looseness, thereby improving the test accuracy of the entire test method.

[0024] During the process of using the resistance testing method, if the probe spacing is too small, it will cause the current to concentrate in a local area and cannot reflect the overall conductive characteristics of the manufactured sand; while if the spacing is too large, it will extend the current path, increasing the risk of electric field distortion and resulting in deviation of the resistivity calculation result; in addition, when the probe spacing is too small, insufficient contact pressure may lead to poor contact between the probe and the sand grains, increasing the contact resistance; if the spacing is too large, a higher pressure is required to achieve stable contact, which may damage the sand body structure; therefore, the optimal probe spacing is also an important parameter to improve the test accuracy of the resistance testing method; thus, in the drying process of the manufactured sand pile, this invention determines the optimal probe spacing in the resistance testing method through preliminary experiments. At the same time, when testing the moisture content of the evenly divided resistance test sand in steps one and five, the probe spacing is the optimal spacing, thereby improving the test accuracy of the resistance testing method.

[0025] The method of the preliminary experiment is as follows: during the drying process of the manufactured sand pile, one portion of the test sand is extracted from the drying process of the manufactured sand pile. Subsequently, the test sand is divided into one portion of dried test sand and several portions of resistance test sand. The several portions of resistance test sand are placed in a test tank with probes of different spacings; then, the moisture content of the dried test sand is detected by the drying method, and the moisture content of the several portions of resistance test sand is detected by the resistance testing method respectively. Let the moisture content of the dried test sand be α'', and the moisture content of the resistance test sand be β1'', β2''...β n ''; select the β that is closest to α'' i ''; detect that the probe spacing of the resistance test sand with a moisture content of β i '' is the optimal spacing; thus, during the detection process of the resistance testing method, the probe spacing is in the best spacing state; it is convenient to improve the detection accuracy; in addition, during the drying process of the manufactured sand pile, multiple portions of the test sand can be extracted for multiple experiments, and the average value is taken to obtain the best spacing; and in steps one and five, the moisture content of the evenly divided resistance test sand is tested only after reaching the standard looseness, thereby improving the test accuracy of the entire test method. In addition, considering the looseness of the sand used for resistance testing and the volume during actual testing (since the number of test samples is large, the volume of each sample is generally small), the probe spacing of a general probe will be within 5 - 10 mm. Therefore, for the preliminary experiment on the probe spacing, the probe spacing can be set to 10 groups, namely, the probe spacing of 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, and 10 mm for a control experiment, and the optimal probe spacing can be selected through the preliminary experiment.

[0026] In the above detection method, the experimental test of looseness, the preliminary experiment of the optimal spacing, and the measurement of the correction amount λ are all carried out during the drying process of the manufactured sand pile. Therefore, when it is necessary to detect the moisture content of the manufactured sand at the time of factory shipment, it can be directly detected, thus greatly improving the detection efficiency of the moisture content at the time of factory shipment.

[0027] Please refer to Figure 1 ; A moisture content control system for manufactured sand, used for the implementation of the on-line moisture content detection method of manufactured sand, includes a control module 1, a resistance test module 4, a drying test module 5, and a data transmission module 6. Inside the control module 1, there is also a calculation module 2 for calculating the correction amount λ. Both the resistance test module 4 and the drying test module 5 are used to detect the moisture content of the test sand. The data transmission module 6 is used to transmit the moisture content data detected by the resistance test module 4 and the drying test module 5 to the calculation module 2. Inside the control module 1, there is also a correction detection module 3 connected to the calculation module 2 and used for outputting A 终 Therefore, during the drying process of the manufactured sand pile, only one portion of the test sand needs to be taken out from the manufactured sand, and then the test sand is divided into several portions. The moisture content is measured through the resistance test module 4 and the drying test module 5. The data transmission module 6 transmits the data measured by the resistance test module 4 and the drying test module 5 to the calculation module 2 for calculating the correction amount λ. When it is necessary to test the moisture content of the manufactured sand pile at the time of factory shipment, only one portion of the test sand needs to be taken out from the manufactured sand pile, and then the test sand is divided into several portions. After obtaining the correction amount λ, the correction detection module 3 detects the moisture content of several portions of the test sand and finally obtains A 终 A 终 A is the actual moisture content of the test sand. Therefore, the detection error of the detection method in the present invention is greater than that of the resistance test method. And during the detection process, the resistance test method is adopted. Therefore, the present invention improves the detection accuracy of the moisture content detected by the resistance test method while improving the detection efficiency, eliminating the situation where the efficiency and accuracy cannot be guaranteed simultaneously in the previous detection.

[0028] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "upper", "lower", "left", "right", "front", "rear" and similar expressions used herein are for illustrative purposes only.

[0029] The above are only the preferred embodiments of the present invention, and do not impose any formal limitations on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the technical content disclosed above within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. An on-line detection method for the water content of manufactured sand, characterized in that, It includes the following steps: Step 1: Extract a portion of sand for testing from the process of drying the manufactured sand pile. Subsequently, divide the tested sand into a portion of dried tested sand and several portions of resistance-tested sand. Step 2: Detect the water content of the sand for drying test by the drying method, and detect the water content of several portions of sand for resistance test by the resistance test method; let the water content of the sand for drying test be α, and the water contents of the sand for resistance test be β1, β2, β3, β4...β n ; Step 3: Subtract α from each of β1 to β n and take the absolute values of the results as γ1 to γ n , and remove j differences greater than 0.5% from γ1 to γ n ; Step 4. Set the correction amount λ as the average value of the remaining γ values, i.e., ; Step 5. When the moisture content of the manufactured sand pile is dried to be close to the factory standard, take out the test sand from the manufactured sand pile, divide the test sand into several equal parts, and quickly detect the moisture content of several parts of the test sand by the resistance test method, and take the detection results as Φ1, Φ2... Φ n ; Step 6. Through Φ n ±λ, obtain n value intervals A n =[Φ n -λ, Φ n +λ], overlap the value intervals from A1 to A n , select the interval with the most overlapping times, and take the midpoint value A 终 , A 终 is the actual water content of the test sand in Step 5.

2. The online detection method for the water content of manufactured sand according to claim 1, wherein: A test column is provided on the central axis of the manufactured sand pile, and several humidity sensors are provided on the test column; the humidity sensors are connected to the detection terminal to feedback the humidity inside the manufactured sand pile, so as to facilitate the preliminary judgment of the water content of the manufactured sand pile, and further preliminarily judge the ex-factory time of the manufactured sand pile.

3. The on-line moisture content detection method of manufactured sand according to claim 1, characterized in that: In Step 1 and Step 5, the tested sand just taken out from the manufactured sand pile is first filtered and stirred in a sealed test chamber. After sufficient filtration and stirring, it is then evenly divided, and the surface of the parts in the sealed test chamber that come into contact with the tested sand is provided with an anti-scratch hydrophobic layer.

4. The on-line detection method for the water content of manufactured sand according to claim 3, characterized in that: After the resistance-tested sand is evenly divided, gently press and adjust the looseness of each portion of the evenly divided resistance-tested sand to ensure that the looseness of each portion of the resistance-tested sand is consistent; at the same time, after the looseness of the resistance-tested sand evenly divided in Step 1 and Step 5 is gently pressed and adjusted, it also remains consistent.

5. The online detection method for the water content of manufactured sand according to claim 4, wherein: During the drying process of the manufactured sand pile, conduct an experimental test on the compaction force of the gentle pressing adjustment, and select the looseness of the resistance-tested sand when the water content is tested by the resistance test method and the test accuracy reaches the highest.

6. The online detection method for the water content of manufactured sand according to claim 5, characterized in that: The method of experimental testing is as follows: a test sand sample is taken from the process of drying the manufactured sand pile, and then the test sand is divided into a dried test sand sample and several resistance test sand samples. The several resistance test sand samples reach different degrees of looseness under the action of different compaction forces. Subsequently, the moisture content of the dried test sand sample is detected by the drying method, and the moisture content of the several resistance test sand samples is detected by the resistance test method. Let the moisture content of the dried test sand sample be α', and the moisture contents of the resistance test sand samples be β1', β2'...β n '; Select the β that is closest to α' i '; Take the looseness of the resistance test sand sample with the detected moisture content of β i ' as the standard looseness, and take the compaction force at this time as the standard compaction force; The resistance-tested sand evenly divided in Step 1 and Step 5 is tested for water content only after reaching the standard looseness.

7. The on-line detection method for the water content of manufactured sand according to claim 3, characterized in that: During the drying process of the manufactured sand pile, determine the optimal spacing of the probe in the resistance test method through preliminary experiments. At the same time, when testing the water content of the resistance-tested sand evenly divided in Step 1 and Step 5, the spacing of the probes is the optimal spacing.

8. The on-line detection method for the water content of manufactured sand according to claim 7, characterized in that: The method of the preliminary experiment is as follows: Take a portion of sand for testing from the process of air-drying the manufactured sand pile. Subsequently, divide the sand for testing into one portion of dried sand for testing and several portions of sand for resistance testing. Place the several portions of sand for resistance testing in a test tank equipped with probes at different spacings. Subsequently, detect the water content of the dried sand for testing through the drying method, and detect the water content of the several portions of sand for resistance testing respectively through the resistance testing method. Let the water content of the dried sand for testing be α'', and the water content of the sand for resistance testing be β1'', β2''...β n ''; Select the β that is closest to α'' i ''; Detect that the probe spacing of the sand for resistance testing with a water content of β i '' is the optimal spacing; The evenly divided sand for resistance testing in Step 1 and Step 5 is tested for water content under the condition that the probe spacing is the optimal spacing.

9. A water content control system for manufactured sand, which is used for implementing the detection method described in any one of claims 1-8, and is characterized in that: It includes a control module, a resistance test module, a drying test module, and a data transmission module. Inside the control module, there is also a calculation module for calculating the correction amount λ. Both the resistance test module and the drying test module are used to detect the water content of the test sand. The data transmission module is used to transmit the water content data detected by the resistance test module and the drying test module to the calculation module. Inside the control module, there is also a correction detection module connected to the calculation module and used to output A 终 of the correction detection module.

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