JP3006334U - Hot water curing equipment for concrete strength test - Google Patents

Abstract

(57) [Summary] [Purpose] A hot water curing device mainly used for short-term compressive strength test by warm water curing at 40 ± 1 ℃ in concrete production process control, and is not affected by calcium components eluted from concrete specimens. To provide a hot water curing device that can be used for a long time. [Structure] An electric heater 11 for heating a concrete specimen A in a curing tank 2 is covered with a fluororesin material 10, and an electric blower 15 is used to circulate hot water in the curing tank.
The curing tank 2 is made of FRP by using the air flow from the above, and adhesion of the calcium component to the curing tank, the heating means 3 and the circulation means is suppressed. A sludge 8 is provided at the bottom of the curing tank to smoothly circulate warm water. A constant temperature state is maintained by the heat insulating effect of the FRP curing tank 2 and the lid member 7, and the power consumption of the electric heater 11 is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hot water curing device used in a hot water curing method in a concrete strength test method.

[0002]

[Prior art]

 There are three types of concrete management: production process control, product control, and quality control. In the compressive strength test mainly for production process control, concrete specimens (20% ± 1 ℃) in constant temperature circulating water ( A sample having a diameter of 10 cm and a height of 20 cm was soaked in water for curing, and a compressive strength test was performed on a specimen with a material age of 28 days.

The applicant of the present application has already provided on the market a constant temperature water circulating device used for underwater curing at 20 ± 1 ° C. This constant-temperature water circulation device has a heat exchanger and a refrigerator installed outside the curing tank, and the submersible pump installed in the heat exchange tank inside the curing tank circulates the water, and at the same time The temperature of the water in the curing tank is adjusted by introducing the heated / cooled cold / hot water to the heat exchange coil in the heat exchange tank by the circulation pump and the circulation pipe, and the constant temperature water of 20 ± 1 ℃ is maintained in the curing tank. It is designed to circulate inside. In this device, the water in the curing tank is not directly circulated to the heat exchanger, but the circulation of water in the curing tank and the circulation of the heat exchange system are separated. There is no risk that the calcium component eluted from the pump will block the heat exchange circulation pump and circulation pipe.

By the way, according to the curing method using the above-mentioned constant temperature water of 20 ± 1 ° C., the specimen of 28 days old is subjected to the compressive strength test and requires a comparatively long-term test. Therefore, a hot water curing method using hot water of 40 ± 1 ° C has been proposed for early determination of concrete strength. This is because by immersing the specimen that had been pre-cured for 2 days in a curing tank in which hot water of 40 ± 1 ° C circulates for 5 days, the age effect of 28 days at 20 ° C can be obtained. It was made possible to perform a compressive strength test in a short period of time.

[0005]

[Problems to be solved by the device]

 When curing concrete with constant temperature water, the calcium component in the cement becomes a problem in addition to water contamination. That is, when a concrete specimen is immersed in water, the calcium component in the leached cement forms calcium hydroxide, which may become powdery or particulate and may be dispersed in water and adhere and grow inside and outside the equipment. is there.

According to the hot water curing method using hot water of 40 ± 1 ° C., the calcium component eluted from the concrete specimen is cured at 20 ° C. Compared with the case, it becomes about 2 to 3 times, and the adverse effect becomes large. That is, as a warm water curing device, a curing tank for housing the specimen, a heating means for heating the water in the curing tank, and a circulation means for circulating the hot water in the curing tank are necessary. , If the calcium component adheres and grows on the heating means for heating the water in the curing tank, the effective heating effect cannot be achieved, and if the calcium component adheres and grows on the circulation device that circulates the hot water, the desired circulation condition is obtained. No constant temperature water is obtained because the temperature distribution in the tank is not constant. Therefore, it is necessary to improve these heating means and circulation device.

As described above, if a heat exchanger is installed outside the curing tank as a heating means and a heat exchange pipe connected to the heat exchanger is introduced into the curing tank, the water in the curing tank is directly heated. Since it is not circulated to the exchanger, it is possible to prevent clogging in the circulation pump and circulation pipe due to the eluted calcium component, but there is a problem that calcium component adheres to the outer surface of the heat exchange pipe, and constant temperature water of 40 ± 1 ℃ is used. There is a problem in the heating ability to obtain. When a submersible pump or the like is used as the circulation means, the calcium component adheres and grows inside the pump or the circulation pipe, resulting in clogging.

Therefore, an object of the present invention is to provide a warm water curing device that can be used for a long period of time without being affected by adhesion and growth of calcium components when targeting constant temperature water of 40 ± 1 ° C. It is in the place of providing.

[0009]

[Means for Solving the Problems]

 That is, this invention is intended to test the strength of concrete, a curing tank for immersing a specimen that has been preliminarily cured, a heating means for heating the water in the curing tank, and a curing tank. It is a warm water curing device for concrete strength test, which is equipped with a circulating means for circulating the hot water, and which is equipped with an efficient heating means and circulating means that can suppress the adhesion of calcium components eluted from concrete specimens as much as possible. It is intended to provide a warm water curing device that uses an electric heater that is directly immersed in the water of the curing tank as the heating means, and has an affinity with calcium components to prevent adhesion and growth of calcium components. It has been found that a material having a low heat resistance, that is, a fluororesin material, preferably a polytetrafluoroethylene resin, is used to cover the outer peripheral surface.

Further, as a circulation means, only an air outlet is provided inside the curing tank, and by connecting with an electric blower installed outside the curing tank, if forced circulation by air injection can be performed, calcium component It was found that there is no water suction mechanism containing water and it is circulated by unilateral blowing, which prevents clogging.

That is, the hot water curing apparatus according to the present invention heats the water in the curing tank for immersing the specimen that has been preliminarily cured in order to test the strength of concrete. And a circulation means that circulates the warm water in the curing tank.The heating means is electrically immersed in the curing tank and covered with a fluorine resin material that does not easily adhere to calcium components in concrete. It is composed of a heater, and the circulation means is composed of an electric blower installed outside the curing tank for blowing air into the curing tank and stirring hot water, and an air blowing path introduced into the curing tank. Polytetrafluoroethylene resin (PTFE) is the most suitable fluororesin material for coating the outer peripheral surface of the electric heater.

In order to prevent the calcium component from adhering to the inner wall surface of the curing tank, it is optimal that at least the inner wall of the curing tank is made of glass fiber reinforced plastic (FRP). The curing tank may be made of stainless steel, iron, plastic, wood, or other material. Iron or stainless steel has toughness, but it is heavy, and calcium components easily adhere to it. In order to maintain a constant temperature of around 40 ° C, the temperature of the heater must be controlled frequently, and the heat loss is large. Also, plastic and wooden materials are lighter in weight and have a greater heat retaining effect than metal ones, but they are not durable and can not be used for a long period of time, and the adhesion of calcium components is large. There is a drawback.

However, when it is made of FRP (glass fiber reinforced plastic), not only the durability is great, but also the adhesion of calcium component is small and the heat retaining property is good. As a means for further improving the heat insulating property and heat retaining property, it is preferable that the curing tank is made of a material having urethane foam as a core material and inner and outer surfaces made of FRP. Further, for the purpose of maintaining a constant temperature of 40 ± 1 ° C, it is desirable to cover the upper surface of the curing tank with a heat-insulating lid so that it can be opened and closed. In addition, in order to circulate the constant temperature water smoothly inside the curing tank and to make the constant temperature water evenly contact the entire surface of all the specimens, it is desirable to install a sludge at the bottom of the curing tank.

Considering the convenience of installation and movement of the device, a curing tank equipped with an electric heater as a heating means and an air outlet as a circulation means, and a machine room equipped with an electric blower, a control unit, etc. It is convenient to mount the entire device, which is arranged side by side, on a trolley with movable casters.

[0015]

[Action]

 As described above, in order to test the strength of concrete, the hot water curing apparatus according to the present invention immerses the specimen that has been preliminarily cured in a curing tank and uses an electric heater as a heating means to cure the tank. The temperature of the water inside is kept at 40 ± 1 ° C, and at the same time, air is jetted into the curing tank through the air outlet using an electric blower, and the hot water is circulated in the curing tank by this jet flow. It is the optimum hot water curing device used in the hot water curing method that uses 40 ± 1 ° C hot water for early determination of concrete strength.

During the curing of the specimen in this curing tank, the calcium component in the concrete, which is the specimen, elutes to form calcium hydroxide, which is dispersed in water in the form of powder or particles. Fluorine resin material that does not allow calcium components to adhere to the electric heater, and because the outer peripheral surface is preferably coated with polytetrafluoroethylene resin, the adhesion and growth of calcium components are suppressed, and it also serves as a circulation means. Has only an air outlet in the curing tank and is connected to an electric blower installed outside the curing tank to perform forced circulation by unidirectional blowout by air injection. Does not occur.

In addition, when the curing tank is made of FRP, it has excellent durability, is resistant to the adhesion of calcium components, and has good heat insulation and heat retention. Furthermore, if the entire curing tank is made of a foamed urethane core material and its inner and outer surfaces made of FRP, heat insulation and heat retention are further improved, and it is most suitable as a constant temperature water tank of 40 ± 1 ° C.

[0018]

【Example】

 Hereinafter, embodiments shown in the accompanying drawings will be described. FIG. 1 is a sectional view of a hot water curing apparatus showing an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a side view of a machine room side.

As shown in the figure, a warm water curing apparatus 1 according to the present invention comprises a curing tank 2 for immersing a columnar specimen A which has been preliminarily cured and a curing tank 2 for testing the strength of concrete. It is provided with a heating means 3 for heating the water therein and a circulation means 4 for circulating the warm water in the curing tank 2.

The curing tank 2 has a tank wall 5 whose inner and outer surfaces are made of polyester FRP with a heat insulating material 6 made of urethane foam or the like as a core material, and whose upper surface is opened, and an appropriate number of supply tanks are provided. The size of the sample A is set so that it can be cured. The open upper surface of the curing tank 2 is openably and closably covered with a lid material 7 containing a plastic heat insulating material so as to keep heat and prevent evaporation of hot water. Further, a large number of holes are formed at the bottom of the curing tank 2, and an ethylene vinyl acetate copolymer (EVA) sludge 8 is installed so as to smooth the circulation of hot water. Although not shown, a drainage device is provided at the bottom of the curing tank 2.

The heating means 3 is composed of an electric heater 11 such as a series heater which is immersed in the curing tank 2 and whose surface is covered with the fluororesin material 10. The heating device 3 is adjacent to the curing tank 2 in a side-by-side manner. It is arranged along the wall surface from the tank wall on the chamber 12 side. In this embodiment, a polytetrafluoroethylene resin (PTFE resin) is used as the fluororesin material 10. This electric heater 11 is energized by PID control that combines a temperature sensor 14 arranged on the tank wall of the curing tank 2 and a temperature information signal output from this temperature sensor with proportional control, product control, etc. Controlled.

The circulation means 4 adopts a so-called gust blower system, and is equipped with an ultra-high pressure type electric blower 15 in the machine room 12 adjacent to the curing tank 2, and is connected to this electric blower to guide it into the curing tank 2. An air outlet 17 of a vinyl chloride pipe having a horizontal nozzle portion 16 extending in the depth direction along the tank wall in the vicinity of the bottom and having an air outlet is provided. Further, the machine room 12 is provided with a control operation unit 18 for controlling temperature and the like. Further, the entire apparatus in which the curing tank 2 and the machine room 12 are arranged side by side is mounted on the carriage 1a having the casters 9 so that the entire apparatus can be easily moved.

In the above structure, when the strength of concrete is tested, a cylindrical specimen A made of fresh concrete is preliminarily cured for about 2 days, and then a flood of 10 cm or more is applied to the upper surface of the specimen A. It is secured and immersed in the curing tank 2 for curing. During this curing, in the curing tank 2, the electric heater 11 is operated based on the temperature information from the temperature sensor 14 to keep the hot water in the curing tank 2 at a temperature of 40 ± 1 ° C. At the same time, air is blown into the curing tank 2 through the air blowing passage 17 using the electric blower 15, and hot water is circulated in the curing tank 2 by this jet flow, and the water temperature is evenly distributed at 40 ± 1 ° C throughout the tank. Maintain a constant temperature. If specimen A is immersed in a curing tank for 5 days in this state, a curing state similar to that of specimen A that has been cured for 28 days at around 20 ° C can be obtained. Therefore, specimen A is removed from curing tank 2 and subjected to a compressive strength test. Should be done.

During this time, the curing tank 2 is closed by a heat insulating lid member 7. Further, since the curing tank 2 is made of FRP having a heat insulating material as a core material, the heat insulating and heat retaining effects are good, and Evaporation of hot water is also suppressed, and it is maintained at a constant constant temperature of 40 ± 1 ℃ with low power consumption.

Even if the calcium component in the concrete which is the specimen A is eluted during the curing of the specimen A in the curing tank 2, the calcium resin does not easily adhere to the electric heater 11. Since the material 10 is covered and the curing tank 2 is made of FRP, the calcium component does not easily adhere to it. Further, since the circulation means is constituted by unidirectional air blowing from the air blowing passage 17 connected to the electric blower 15, there is no mechanism portion for sucking the calcium component, and it is difficult for the air blowing passage 17 to adhere to the air blowing passage 17. Thus, it is possible to provide the warm water curing apparatus 1 that can be used for a long period of time.

[0026]

[Effect of device]

 As is clear from the above detailed description, according to claim 1, the electric heater for heating the concrete specimen in the curing tank is coated with a fluororesin material, preferably polytetrafluoroethylene resin, and cured. Since the hot water in the tank is circulated using the air flow from the electric blower, the heat exchanger and the submersible pump used in the conventional method can be installed in the curing tank as compared to the test piece. It is possible to provide a warm water curing apparatus that makes it difficult for the eluted calcium component to adhere to the heating means and the circulation means and can withstand long-term use.

Further, according to claim 3, since the curing tank is also made of FRP, it is possible to suppress the attachment of the calcium component and to exhibit the heat insulating property to reduce the power consumption of the electric heater. Further, the weight of the entire device can be reduced.

According to the fourth aspect, since the urethane foam is used as the core material and the inner and outer surfaces thereof are made of FRP, the heat insulating and heat retaining effects are good.

Further, according to claim 5, since the upper part of the curing tank is covered with a heat-insulating lid material, the heat retaining effect in the curing tank becomes large even when kept in warm water of about 40 ° C. It is possible to further reduce the power consumption of the heater.

According to claim 6, since the sludge for mounting the specimen on the bottom of the curing tank is provided, the circulation of warm water is smoothly performed, and all the specimens are uniformly immersed in the warm water. The state is obtained.

According to the seventh aspect, since the entire apparatus including the curing tank and the machine room is mounted on the trolley with casters, there is also an advantage that it can be easily moved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a warm water curing apparatus according to the present invention,

FIG. 2 is a plan view of the same,

FIG. 3 is a side view of a machine room side.

[Explanation of symbols]

 1 Hot Water Curing Device 1a Cart 2 Curing Tank 3 Heating Means 4 Circulating Means 5 Tank Walls 6 Heat Insulation Materials 7 Lid Materials 8 Sinks 9 Castors 10 Fluororesin Materials 11 Electric Heaters 15 Electric Blowers 16 Horizontal Nozzles 17 Air Blowouts A

Claims (7)

[Scope of utility model registration request] 1. To test the strength of concrete,
A curing tank for immersing the specimen that has been preliminarily cured,
It is equipped with a heating means for heating the water in the curing tank and a circulation means for circulating the warm water in the curing tank. The heating means is immersed in the curing tank and the calcium component in the concrete does not easily adhere to it. It consists of an electric heater covered with a fluororesin material, and the circulation means consists of an electric blower installed outside the curing tank that blows air into the curing tank and stirs hot water, and an air blowing path that leads to the curing tank. A hot water curing device for concrete strength test, which is characterized in that 2. The hot water curing apparatus according to claim 1, wherein the fluororesin material is polytetrafluoroethylene resin. 3. The warm water curing apparatus according to claim 1, wherein at least the inner wall of the curing tank is made of FRP. 4. The warm water curing apparatus according to claim 1, wherein the curing tank is made of a material having urethane foam as a core material and inner and outer surfaces made of FRP. 5. The hot water curing apparatus according to claim 1, 2, 3 or 4, wherein an upper portion of the curing tank is covered with a heat insulating lid so as to be openable and closable. 6. The warm water curing apparatus according to claim 1, further comprising a sludge on which a specimen is placed at the bottom of the curing tank. 7. The hot water curing apparatus according to claim 1, wherein the entire apparatus is mounted on a movable cart with casters.