JP6142844B2 - Unit water volume measuring device for concrete - Google Patents

Description

  The present invention relates to a method for measuring a unit water amount of concrete for measuring a unit water amount of fresh concrete.

  Conventionally, as a method for measuring the unit water content of concrete, etc., for determining the unit water content contained in concrete and mortar, a mortar sample is taken from fresh concrete, the weight of this sample is measured, and then the sample is heated under reduced pressure to evaporate moisture. Then, by measuring the weight of the sample again, there has been proposed a concrete unit water amount measuring apparatus in which the estimated unit water amount is obtained from the difference in weight between the sample before moisture evaporation and the sample after moisture evaporation (for example, Patent Document 1). . According to the heat drying method using such a unit water amount measuring apparatus, the sample is heated in the reduced pressure space, so that the boiling point of water is lowered, and thus water can be evaporated in a short time. For this reason, a large-scale heating device is not required, and water can be evaporated by heating at a low temperature for a short time, so that the promotion of cement hydration can be suppressed.

  In addition, the electronic water balance used in the weight measuring instrument has a structure that is not easily affected by heat during drying, and the unit water volume of concrete that realizes miniaturization by integrating the drying means and the weight measuring means integrally. A measuring device has been proposed (for example, Patent Document 2). According to such a configuration of Patent Document 2, since the weight measuring device is arranged below the sample plate in the sample chamber, the main body can be formed compactly, and the sample plate is not in contact with the support rod of the weight measuring device. Since it is configured in the position, heat conduction can be suppressed compared to a configuration in which the sample pan and the support rod of the weight measuring device are in contact with each other, and the weight measuring means is less susceptible to heat during heating of the sample pan. Thus, the weight can be accurately measured using an electronic balance or the like.

JP-A-8-338838 Utility Model Registration No. 3076378

  Certainly, according to the configurations of Patent Documents 1 and 2, the sample can be heated under reduced pressure to evaporate the water, so that the unit water content of the concrete can be measured by heating at a low temperature for a short time. However, in Patent Documents 1 and 2, since it is necessary to mount two or more vacuum pumps in order to perform reduced pressure heating, the cost of the apparatus increases and the number of parts increases, so the entire apparatus is large. In order to improve the convenience of the apparatus, further downsizing has been desired.

  Therefore, the problem to be solved by the present invention is that the sample can be completely dried in a short time in the same manner as the heat drying under reduced pressure, not the heat drying method under reduced pressure. An object of the present invention is to provide a concrete unit water volume measuring device capable of realizing the downsizing.

The concrete unit water content measuring apparatus according to the invention of claim 1 collects a mortar sample from fresh concrete, measures the weight of the sample, heats the sample to evaporate water, and measures the weight of the sample again. In a concrete unit water amount measuring apparatus for obtaining an estimated unit water amount based on a weight difference of a sample after moisture evaporation, a machine body having a lid that can be opened and closed at an upper part, a sample chamber provided in the machine body, and the sample A sample dish that can be loaded and unloaded in the room, a weight measuring means that is provided in the main body of the machine and that measures the weight of the sample dish, and a steam exhaust that is provided in the lid and discharges steam generated from the sample to the outside. And a first heating means provided below the steam discharge fan for heating the sample dish from above, and a second heating means for heating the sample dish from below, The heating means, the vent hole penetrating from the sample dish is placed downwardly into the steam discharge fan disposed above is provided on the lower surface of the first heating means, on said vent hole and coaxially It is arranged, and a heat transfer plate larger than the vent hole is provided .

The concrete unit water content measuring apparatus of the invention of claim 2 collects a mortar sample from fresh concrete, measures the weight of the sample, heats the sample to evaporate water, and measures the weight of the sample again. In a concrete unit water amount measuring apparatus for obtaining an estimated unit water amount based on a weight difference of a sample after moisture evaporation, a machine body having a lid that can be opened and closed at an upper part, a sample chamber provided in the machine body, and the sample A sample dish that can be loaded and unloaded in the room, a weight measuring means that is provided in the main body of the machine and that measures the weight of the sample dish, and a steam exhaust that is provided in the lid and discharges steam generated from the sample to the outside. And a first heating means provided below the steam discharge fan for heating the sample dish from above, and a second heating means for heating the sample dish from below, The heating means, the vent hole penetrating from the sample dish is placed downwardly into the steam discharge fan disposed above is provided, wherein the first heating means, is fixed to the lid side, said first A groove is formed on the lower surface of the heating means, and a seal member is fitted into the groove .

Unit water content measuring device of the concrete aspect of the present invention according to claim 3, Oite to claim 1, wherein the first heating means, fixed to said lid side, the groove is formed on the lower surface of the first heating means, A seal member is fitted into the groove.

A concrete unit water amount measuring apparatus according to a fourth aspect of the present invention is characterized in that, in the first or third aspect , the heat transfer plate is fixed with a spacer provided between the heat transfer plate and the first heating means.

  According to a fifth aspect of the present invention, there is provided a concrete unit water amount measuring apparatus according to the fourth aspect, wherein an installation distance of the heat transfer plate formed by the spacer with respect to the first heating means is in a range of 2 to 4 mm. Features.

  The concrete unit water amount measuring device of the invention of claim 6 is characterized in that, in any one of claims 1 to 5, a taper portion is provided on the lower surface of the first heating means so as to incline upward toward the inside. Features.

According to the invention of claim 1, since the sample can be completely dried in a short time and no pressure reducing means is required, the cost of the apparatus can be kept lower than that of the heat drying method using a vacuum pump under reduced pressure. The weight can be reduced by downsizing the apparatus. In addition, the sample can be dried in a shorter time, and when the water adhering to the steam discharge fan drops as water droplets, it falls on the heat transfer plate provided to close the vent hole, It is possible to prevent the evaporated water from returning to the sample pan.

According to the invention of claim 2, since the sample can be completely dried in a short time and no pressure reducing means is required, the cost of the apparatus can be reduced compared to the heat drying method using a vacuum pump under reduced pressure. The weight can be reduced by downsizing the apparatus. The seal member is elastically deformed to close the gap between the sample pan and the first heating means, and a flow path is formed from the sample chamber to the steam discharge fan provided in the lid through the vent hole. The steam generated from the can be reliably guided.

  According to the invention of claim 3, the seal member is elastically deformed to close the gap between the sample pan and the first heating means, and from the sample chamber to the steam discharge fan provided in the lid through the vent hole. A flow path is formed, and the vapor generated from the sample can be reliably guided.

  According to the invention of claim 4, a gap can be formed between the first heating means and the heat transfer plate, and the set distance of the heat transfer plate with respect to the lower surface of the first heating means can be appropriately adjusted. it can.

  According to the invention of claim 5, it is possible to measure the unit water amount with little error.

  According to the invention of claim 6, even when the steam generated from the sample is efficiently guided to the steam discharge fan and the water remains on the tapered portion, the water is removed from the sample dish by the inclination of the tapered portion. It is possible to flow to the part side and to prevent water from returning to the sample pan.

It is a front view of the unit water content measuring apparatus which shows Example 1 of this invention. It is a top view of the unit water quantity measuring apparatus which shows Example 1 of this invention. It is a side view of the unit water content measuring apparatus which shows Example 1 of this invention. It is a front view of the unit water content measuring apparatus which shows Example 1 of this invention. It is a partial expanded sectional view of the unit water content measuring apparatus which shows Example 1 of this invention.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention.

  1 to 5 show an embodiment of the present invention, and an embodiment of the present invention will be described with reference to the accompanying drawings. In the concrete unit water amount measuring apparatus 1 in the present embodiment, the machine body 2 has a vertically long box shape, and a lid 4 that can be opened and closed by a hinge portion 3 provided on the back side of the machine body 2 is the machine body 2. A cover 5 is provided so as to cover the upper opening, and a handle 5 is provided at the front upper portion of the lid 4, and a steam exhaust fan 6 for exhausting steam is provided at the center of the upper surface of the lid 4. In addition, a liquid crystal display unit 8 with a touch panel for inputting / outputting information data related to the sample 7 and operating instructions for unit water volume measurement is provided on the upper front surface of the machine body 2, and a thermal transfer is provided on the right side at the lower front surface. A printing device 9 such as a printer is provided, and a voltmeter 10 that easily checks the voltage and prevents a voltage drop and a control unit 11 that performs operation control and data calculation are arranged above and below the lower left side of the front surface. Has been. Further, a cooling fan 12 for cooling the heat inside the machine main body 2 is provided on the side surface of the machine main body 2, so that the cooling time of the machine can be shortened after the test.

  The lid 4 has a circular ventilation hole 13 penetrating in the vertical direction at a lower position than the steam discharge fan 6 and is a first heating means having a substantially annular shape in plan view. A heater plate 14 is provided. The upper heater plate 14 is disposed so that the center of the steam discharge fan 6 and the center of the vent hole 13 are on a concentric axis, and a heat transfer plate 15 is disposed on the lower surface of the upper heater plate 14 via a spacer 16. Fixed. Then, when the lid 4 integrally formed with these is opened, a sample pan 18 made of stainless steel or the like is fixed to the machine body 2 in the sample chamber 17 provided in the machine body 2. It is detachably mounted on the lower heater plate 19 as a heating means, and an electronic balance 20 as a weight measuring instrument is accommodated in the lower part of the sample chamber 17. The sample pan 18 is provided with a side wall portion 22 that rises perpendicularly to the bottom surface portion 21 around the bottom surface portion 21 that has a substantially circular shape, and an end portion that is bent outwardly from the side wall portion 22 and vertically. A portion 23 is formed, and the upper surface of the flange portion 23 has a flat portion 24.

  Further, a groove 25 is formed on the lower surface of the upper heater plate 14 slightly inside the outer peripheral edge, and a packing 26 as an annular seal member is fitted therein. When the lid 4 is closed, the packing 26 comes into contact with the flat surface portion 24 which is the upper surface of the collar portion of the sample dish 18 and is elastically deformed so that the gap closes between the sample dish 18 and the upper heater plate 14. Since the flow of air from the side wall side of the sample pan 18 can be blocked, the vapor generated from the sample 7 by heating the sample pan 18 when the lid 4 is closed causes the sample chamber 17 to be heated. Then, a flow path is formed through the vent hole 13 to the steam discharge fan 6 provided in the lid body 4 so that the steam can be reliably guided.

  Furthermore, a taper portion 27 that is slightly inclined upward is formed on the lower surface of the upper heater plate 14 from the inside of the groove 25 portion to the vent hole 13. A slight gap is formed between the heat transfer plate 15 fixed to the upper heater plate 14 via the spacer 16 and the upper heater plate 14. Vapor generated from the sample 7 when the sample pan 18 is heated by this gap is guided from the sample chamber 17 to the vent hole 13, and is sent from the vent hole 13 to the outside of the main body by the vapor discharge fan 6. Discharged.

  The heat transfer plate 15 fixed to the upper heater plate 14 via the spacer 16 is coaxial with the circularly formed vent hole 13 of the upper heater plate 14 and covers the lower surface of the upper heater plate 14 so as to cover it. And is formed in a circular shape whose shape is larger than the diameter of the vent hole 13. By forming the heat transfer plate 15 in a circular shape, heat can be evenly transferred to the heat transfer plate 15 when a voltage is applied and the heat transfer plate 15 is heated. Moreover, since the heat transfer plate 15 is formed with a diameter larger than the diameter of the vent hole 13, the water adhering to the steam discharge fan 6 drops as water droplets and falls downward from the vent hole 13. In this case, this functions as a drain pan, and the heat transfer plate 15 receives water droplets dripping from above, evaporates the water droplets again, and reliably discharges them from the machine body 2 to the outside by the steam discharge fan 6. it can. As a result, it is possible to prevent moisture that should be discharged from the steam discharge fan 6 from returning to the sample pan 18 again. The heat transfer plate 15 may be made of any material such as aluminum, stainless steel or copper, but copper is used from the viewpoint of high water droplet adhesion rate and high thermal conductivity at high temperature. Is preferred. Further, the steam discharge fan 6, the vent hole 13, and the heat transfer plate 15 are preferably arranged on a concentric shaft so that the steam generated from the sample 7 can be efficiently discharged from the machine body 2 to the outside. .

  Next, the effect | action is demonstrated about the unit water quantity measuring apparatus 1 of the concrete provided with the said structure. When performing a heat-drying test to measure the unit water volume, fresh concrete, which is fresh concrete in which water, cement, fine aggregate, coarse aggregate, and admixture are blended in a known ratio, and a concrete mixer truck are used. A portion of the ready-mixed concrete carried into the site is taken out, and coarse aggregate is removed from the ready-mixed concrete by wet screening to collect a mortar sample 7 (hereinafter simply referred to as sample 7), and approximately 100 g is used. In this example, the sample 7 is most preferably about 100 g in order to dry completely in a short time, and the sample 7 of about 80 g to 120 g is used. Before the measurement, the lid 4 of the unit water amount measuring device 1 is opened, the sample 7 is placed in the sample pan 18, placed on the lower heater plate 19, and the lid 4 is closed. Then, the packing 26 attached to the lower surface of the upper heater plate 14 provided integrally with the lid 4 is brought into contact with the flat surface portion 24 on the upper surface of the flange portion 23 of the sample dish 18 so that the sample dish 18 and the upper heater plate are brought into contact with each other. Since 14 is in close contact and the gap is closed, only the flow path connected to the vent hole 13 is provided from the inside of the sample chamber 17 to the outside of the main body 2. In this state, the unit water amount measuring device 1 is operated to start measurement.

  When the measurement starts, the sample weight before drying is first measured by the electronic balance 20 disposed below the sample pan 18 and stored in the control unit 11. When the upper heater plate 14 and the lower heater plate 19 are operated under the control of the control unit 11, they heat and dry the sample 7 together with the heat transfer plate 15 fixed to the upper heater plate 14 via the spacer 16. . In the present embodiment, the sample 7 is heated and dried from above and below by the upper heater plate 14 and the lower heater plate 19, so that the sample 7 can be heated to the boiling point in a short time.

  The moisture in the sample 7 is vaporized and vaporized when heating and drying starts and reaches the boiling point, and when this rises, the vapor is guided to the tapered portion 27 of the upper heater plate 14, so that the upper heater plate 14 and the heat transfer plate The air passes through the ventilation hole 13 through the gap 15 and is discharged from the machine body 2 to the outside by the steam discharge fan 6. At this time, when water adhering to the steam discharge fan 6 drops as water droplets, the water drops on the heat transfer plate 15 provided so as to close the vent hole 13, so that the evaporated water is removed from the sample pan 18. Returning to can be prevented. In addition, the water on the heat transfer plate 15 is reheated by the heat transfer plate 15 to be vaporized into steam, which is reliably discharged from the steam discharge fan 6 to the outside. It will not remain. Thus, after the sample 7 is heated and dried, the control unit 11 measures the weight of the sample after drying, and calculates the weight difference from the weight of the sample before drying. Then, the estimated unit water amount is calculated by the control unit 11 in light of the weight of the known cement, water and fine aggregate before and after drying. In addition, when the vapor generated from the sample 7 adheres to the taper portion 27 and water remains on the taper portion 27, the taper portion 27 is inclined and drops as a water droplet into the sample pan 18. Since water flows through the tapered portion 27 to the flange portion 23 side of the sample plate 18 before, even if water remains in the tapered portion 27, it can be prevented from returning to the sample plate 18. Moreover, terms, such as unit water quantity, are known by concrete mixing, and terms, such as an estimated unit water quantity, show what was calculated by this measuring method.

  Here, in the present embodiment, the steam generated from the sample 7 is guided to the vent hole 13 connected to the steam discharge fan 6, that is, the spacer 16 between the upper heater plate 14 and the heat transfer plate 15. It is provided with a configuration in which a gap is provided through the. In terms of configuration, the spacer 16 can adjust the set distance of the heat transfer plate 15 relative to the lower surface of the upper heater plate 14 depending on the measurement conditions, but if the installation distance is not appropriate, the error in the measurement results will increase. . For example, if the installation distance of the heat transfer plate 15 relative to the lower surface of the upper heater plate 14 is too long, the vaporized water adheres to the heat transfer plate 15 before being guided to the vent hole 13 by the tapered portion 27. If the liquid is dripped down through the heat transfer plate 15 and returns to the sample pan 18, and if it is too short, the vapor is not exhausted from the sample chamber 17, and the sample 7 The water inside cannot be completely evaporated, and an error occurs in the measurement result after the measurement. Therefore, in this example, the optimum installation distance between the upper heater plate 14 and the heat transfer plate 15 was determined by the following heat drying test.

  First, 128 g to 130 g of the sample 7 was heat-dried at 90 V with no load for approximately 6 minutes using the unit water amount measuring apparatus 1 of this example. Details of common sample composition are shown in Table 1. The installation distance of the heat transfer plate 15 with respect to the lower surface of the upper heater plate 14 is 1 mm set by only one copper washer, 3 mm set by only the spacer 16, and three copper plates in addition to the spacer 16. A heat drying test was conducted at 6 mm set by a washer.

  As a result of the test, when the installation distance is 1 mm, as shown in Table 2, the estimated water amount is 166.0 kg with respect to the unit water amount 169 kg in the sample composition table, and the difference is −3.0 kg, which is a large error. Occurred. In addition, when the installation distance is 6 mm, as shown in Table 3, the estimated water amount is 165.8 kg with respect to the unit water amount 169 kg in the sample composition table, and the difference is -3.2 kg, which is also large. An error has occurred. On the other hand, when the installation distance is 3 mm, as shown in Table 4, the estimated water amount for the first time is 168.5 kg and the opening difference is -0.5 kg with respect to the unit water amount 169 kg in the sample 7 composition table. In addition, the estimated water volume for the second time is 169.3 kg, and the difference is 0.3 kg. The estimated amount of water for the third time was 168.0 kg, the difference in opening was -1.0 kg, and the error was 1 kg or less, resulting in the least error. When the installation distance was 1 mm or 6 mm, water droplets were confirmed on the heat transfer plate 15.

  Therefore, from the above test results, the installation distance of the heat transfer plate 15 with respect to the upper heater plate 14 is preferably about 3 mm, and the unit water amount can be measured with a small error by being installed in the range of at least 2 to 4 mm. Shall.

  As described above, in this embodiment, the mortar sample 7 is collected from the fresh concrete, the weight of the sample 7 is measured, the sample 7 is heated to evaporate the moisture, the weight of the sample 7 is measured again, and the moisture is measured. In a concrete unit water amount measuring apparatus 1 for obtaining an estimated unit water amount based on a difference in weight of a sample 7 after evaporation, a machine body 2 having a lid 4 that can be opened and closed at an upper part, a sample chamber 17 provided in the machine body 2, A sample pan 18 that can be loaded into and removed from the sample chamber 17, an electronic balance 20 that is provided in the main body 2 and measures the weight of the sample pan 18, and a vapor that is provided in the lid 4 and is generated from the sample 7. Are provided below the steam discharge fan 6, and the upper heater plate 14 is provided as a first heating means for heating the sample dish 18 from above, and the sample dish 18 is heated from below. Lower heater as second heating means -The plate 19 is provided, and the upper heater plate 14 is provided with a vent hole 13 penetrating from the lower sample pan 18 to the upper steam discharge fan 6 so that the sample 7 is completely dried in a short time. In addition, since no pressure reducing means is required, the cost of the apparatus can be reduced compared to a heat drying method using a vacuum pump under reduced pressure, and weight reduction is realized by downsizing the apparatus. be able to.

  In addition, since the heat transfer plate 15 which is disposed concentrically with the vent hole 13 on the lower surface of the upper heater plate 14 and is larger than the vent hole 13, the sample 7 can be dried in a shorter time. When the water adhering to the steam discharge fan 6 drops as water droplets, it falls on the heat transfer plate 15 provided to close the vent hole 13, so that the evaporated water returns to the sample pan 18. Can be prevented.

  Further, the upper heater plate 14 is fixed to the lid body 4 side, and a groove 25 is formed on the lower surface of the upper heater plate 14. Since the packing 26 as a seal member is fitted into the groove 25, the packing 26 is elastically deformed. A gap is formed between the sample pan 18 and the upper heater plate 14, and a flow path is formed from the sample 7 chamber through the vent hole 13 to the vapor discharge fan 6 provided in the lid 4, and the vapor generated from the sample 7 is discharged. It can be surely guided.

  In addition, since the heat transfer plate 15 is fixed by providing a spacer 16 between the upper heater plate 14, a gap can be formed between the upper heater plate 14 and the heat transfer plate 15, and the upper heater The set distance of the heat transfer plate 15 with respect to the lower surface of the plate 14 can be adjusted as appropriate.

  Moreover, since the installation distance with respect to the upper heater plate 14 of the heat transfer plate 15 formed by the spacer 16 is in the range of 2 to 4 mm, it is possible to measure the unit water amount with little error.

  In addition, since a tapered portion 27 that is inclined inward and upward is provided on the lower surface of the upper heater plate 14, the steam generated from the sample 7 is efficiently guided to the steam discharge fan 6, and water is placed on the tapered portion 27. Even if it remains, water can flow toward the flange 23 side of the sample pan 18 due to the inclination of the tapered portion 27, and water can be prevented from returning to the sample pan 18.

1 Unit water volume measuring device 2 Machine body 4 Lid 6 Steam exhaust fan 7 Sample
13 Vent
14 Upper heater plate (first heating means)
15 Heat transfer plate
16 Spacer
17 Sample room
18 Sample pan
19 Lower heater plate (second heating means)
25 groove
26 Packing (seal member)
27 Taper

Claims (6)

After taking a mortar sample from fresh concrete and measuring the weight of the sample, the sample is heated to evaporate the moisture, and the weight of the sample is measured again. In an apparatus for measuring the unit water content of concrete, a machine body having a lid that can be opened and closed at the top, a sample chamber provided in the machine body, a sample pan that can be loaded into and removed from the sample chamber, and a machine body A weight measuring means for measuring the weight of the sample pan; a steam exhaust fan provided on the lid for exhausting steam generated from the sample to the outside; and provided below the steam exhaust fan. And a first heating means for heating the sample dish from above and a second heating means for heating the sample dish from below, and the first heating means is provided above the sample dish arranged below. Arrangement Vent hole is provided which penetrates into steam discharge fan that is, the lower surface of the first heating means, the disposed vent hole and coaxially on said the vent large heat transfer plate than is provided A unit water volume measuring device for concrete. After taking a mortar sample from fresh concrete and measuring the weight of the sample, the sample is heated to evaporate the moisture, and the weight of the sample is measured again. In an apparatus for measuring the unit water content of concrete, a machine body having a lid that can be opened and closed at the top, a sample chamber provided in the machine body, a sample pan that can be loaded into and removed from the sample chamber, and a machine body A weight measuring means for measuring the weight of the sample pan; a steam exhaust fan provided on the lid for exhausting steam generated from the sample to the outside; and provided below the steam exhaust fan. And a first heating means for heating the sample dish from above and a second heating means for heating the sample dish from below, and the first heating means is provided above the sample dish arranged below. Arrangement Vent hole is provided which penetrates into steam discharge fan is, the first heating means, is fixed to the lid side, the groove on the lower surface of the first heating means is formed, the sealing member in the groove A unit water content measuring device for concrete, characterized in that is fitted . Said first heating means, fixed to said lid side, the groove on the lower surface of the first heating means is formed of concrete of claim 1 Symbol mounting, characterized in that the sealing member is fitted into the groove Unit water volume measuring device. The concrete unit water quantity measuring device according to claim 1 or 3, wherein the heat transfer plate is fixed by providing a spacer between the heat transfer plate and the first heating means. The concrete unit water content measuring apparatus according to claim 4, wherein an installation distance of the heat transfer plate formed by the spacer with respect to the first heating means is in a range of 2 to 4 mm. The unit water amount measuring apparatus for concrete according to any one of claims 1 to 5, wherein a taper portion that is inclined inward and upward is provided on a lower surface of the first heating means.

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