JPS5939169B2 - Thickener dissolution method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates primarily to a method for dissolving a thickener for dust suppression used during concrete spraying work in piles, etc., and an apparatus therefor.

In general, in construction using the concrete shotcrete method (NATM), dust generated during the spraying of shotcrete is viewed as a problem as part of environmental hygiene management for work inside piles.

Particularly in the dry and semi-wet concrete spraying methods that have been widely used in recent years, the concrete material (mixture of cement, sand, coarse aggregate, etc.) that has been dry mixed in the spraying machine is air-transported through a transfer pipe using compressed air. At the same time, pressure water is injected into the pipe from a water injection hole provided near the nozzle at the tip of the transfer pipe, and the concrete material in the form of a dry mix is turned into ready-mixed concrete within a short time while being sprayed from the nozzle at the tip. Compared to the wet method, a large amount of floating dust is generated during spraying, resulting in a very poor working environment. In addition, loss due to rebound of fresh concrete during concrete spraying was a problem that could not be overlooked. Therefore, recently, consideration has been given to adding thickeners that are effective in suppressing dust and reducing rebound. Here, the thickener is a white powder or granular water-soluble thermoplastic resin (PEO) with a molecular weight of 100,000 to several million obtained by polymerizing ethylene oxide, commonly known as a water-soluble polymer, or methyl cellulose. White powdery water-soluble thermoplastic resins (Siripon) are known as main ingredients, and these thickeners completely dissolve in water, and their solution shows high viscosity at low concentrations and does not coagulate. It is effective to add a thickener in an amount of about 0.05% by weight of cement dissolved in water, but it takes a considerable amount of time to dissolve in ice, and this Therefore, rather than adding a thickener in powder form to a dry mix concrete material, pumping it into a transfer pipe, adding water at the tip nozzle, and spraying, the thickener is added in advance to a separate tank with water. It is far more effective to completely dissolve the aqueous solution into the concrete material in the form of a dry mix using the nozzle at the tip of the transfer pipe.

However, in the past, a powder thickener was dissolved in water and the aqueous solution was applied to the concrete near the nozzle at the tip of the spraying machine's transfer pipe, which could be installed incidentally to the main body of the spraying machine at a concrete spraying site such as on a highway. There is no equipment that can supply and add thickeners to materials, and the only thing that has been done is to add a pre-dissolved aqueous solution of a thickener in a factory.

In other words, although the above-mentioned thickeners are originally completely water-soluble, it takes a considerable amount of time to completely dissolve them, and it is difficult to dissolve them if the dissolving means is not appropriate. There are many troublesome problems such as a decrease in the viscosity of the aqueous solution.For example, if thickener powder is not sufficiently dispersed in water and flocs form, the air in the flocs will not escape and form a stable hydrophobic band. (Mamako) is formed, making it extremely difficult to dissolve.Also, even if the thickener particles are uniformly dispersed in water, if the mixing force (stirring) is too strong, the thickener molecules will be cut and the viscosity will decrease. On the other hand, if it is too weak, it will become albumen-like and the exfoliation and dispersion of molecules will not proceed smoothly, causing problems such as non-uniform viscosity and requiring a long dissolution time. For this reason, a compact device that can be installed at concrete spraying sites such as in roads and that can perform appropriate melting in a short period of time has not yet been developed, and it is currently hoped that it will be realized as soon as possible. It was hot. This invention was made in view of the above circumstances, and its purpose is to dissolve the above-mentioned thickener in water very easily and appropriately, and in a short period of time. It is an object of the present invention to provide a method for dissolving a thickener and an apparatus therefor which are very effective for use at concrete spraying sites.

In other words, this invention creates a vortex in water placed in a stirring tank by rotating the stirrer at high speed, and in this state, a thickener made of a water-soluble thermoplastic resin in the form of powder or granules is added little by little into the water. By fully dispersing the thickener, and after adding and dispersing a predetermined amount of the thickener, the agitator is rotated at a low speed and stirred without adversely affecting the molecular structure of the thickener (viscosity reduction). The present invention is characterized by a method and apparatus that can achieve appropriate dissolution with high efficiency.

An embodiment of the present invention will be described below with reference to the drawings. First, for the sake of explanation, the device of this invention is equipped with the functions of automatically dissolving a thickener, storing the aqueous solution, and automatically supplying it to a concrete spraying machine, and 1 in Fig. 1 is a stirring tank. , 2 is a storage tank provided adjacent to the stirring tank 1 on the same base (not shown). 3 is a water supply pipe mechanism with a water valve 3a such as an electromagnetic valve for supplying water from a water storage tank (not shown) etc. into the stirring tank 1 as appropriate; 4 is a water supply pipe mechanism with a water valve 3a such as a solenoid valve for supplying water from above into the stirring tank 1 from above; A thickener quantitative supply mechanism such as a feeder with a preset counter that gradually introduces a thickener made of a water-soluble thermoplastic resin, and 5 is a stirrer installed by inserting a shaft with rotating blades into the center of the stirring tank 1. (agitator), the rotation speed is high by timer control (not shown).
It is a variable speed type that can be switched to two low gears.

6 in the figure is a cage-shaped strainer 1 installed in the stirring tank 1 so as to have a double-walled structure separating the inside and outside of the tank. In this structure, the upper frame is supported by an elastic support member 7 such as a buffer rubber so as to be freely movable within an appropriate range with respect to the stirring tank 1, and is vibrated by a vibrator 8 disposed on the upper part of the upper frame. It's getting old. Reference numeral 9 denotes a water pump mechanism with a water pump 9a that sucks up the aqueous solution in the stirring tank 1 from the bottom thereof and transfers it into the storage tank 2.

Incidentally, on the side wall of the stirring tank 1, an upper limit level sensor LSl for detecting the liquid level is attached near the upper end, and a lower limit level sensor LS2 is attached to the lower end. These level sensors LS1 and LS2 are commercially available electromagnetic relay type switches called Nibocompact, and they operate to detect when a dielectric liquid covers the probe protruding into the tank 1, and the liquid separates. These level sensors LS1 and LS2 are placed at a position laterally shifted from directly below the mouth of the water supply pipe 3a of the water supply mechanism 3 so as not to directly hit the water falling from the water supply pipe 3a. In addition, an air blowing mechanism 10 with an air valve 10a is provided directly above the level sensors LSl and LS2 to blow dinit air from a nozzle toward the probes to remove adhering matter. This prevents the level sensors LS1 and LS2 from malfunctioning.
A level sensor LS3 similar to the above is also provided on the side wall of the storage tank 2, located near the lower end. A pressure pump 1 sends the aqueous solution in the storage tank 2 to a nozzle at the tip of a transfer pipe (not shown) of a concrete spraying machine.
A supply pipe mechanism 11 with 1a is connected. In addition, in this supply pipe mechanism 11, a pressure pump 11a operates in conjunction with the operation of the concrete spraying machine, and when concrete spraying is finished, pressure feeding of the aqueous solution is stopped, and excess aqueous solution is drained into the tank 2 by a condensation valve 11b. It is now possible to return to In addition, the various devices and mechanisms mentioned above include level sensors LSL, LS2,
Automatic control is performed as shown in the time chart of FIG. 2 by a control circuit (not shown) that operates by taking in the detection signal of LS3 as an input signal. To describe the method for dissolving the thickener and storing and supplying it using the apparatus with the above-mentioned configuration, first, although not shown in FIG.
Turn the main switch (push button switch) to 0N.

The level sensors LS1 and LS2 confirm that there is no predetermined amount of water in the stirring tank 1, and the water valve 3a of the supply mechanism 3 opens, thereby starting water supply. Therefore, a predetermined amount (100 in this example) is added to the stirring tank 1.
When the upper limit level center LS1 is activated by adding water to the liter (1), the water valve 3a is automatically closed and the water supply is stopped, and at the same time, the agitator 5 and the vibrator 8 of the strainer 16 are started. The stirrer 5 rotates at high speed (approximately 11 m/cm in circumferential speed of the stirring blade).
Sec) to generate a vortex in the water in the tank 1, and the vibrator 8 appropriately vibrates the entire strainer 16.
On the other hand, T seconds after the start of the agitator 5 (approximately 2 seconds after the water in the tank 1 generates a vortex), a timer or a delay circuit causes the feeder 1 of the thickener constant supply mechanism 4 to adjust the water surface to the vortex state. The thickener is started to be added in small amounts from above, and at the same time the preset counter, which was in the reset state, starts counting. In this way, the thickener dropped in small amounts is efficiently dispersed in the water while being sucked deep below the water surface by the eddy current, and when the preset counter reaches the preset count value ( When approximately 0.1% of thickener by weight is added to the feeder, the feeder stops adding the thickener, and from that point on, a timer etc. is set to start T2 seconds later (when a certain amount of thickener is submerged in the water). (After approximately 3 seconds until sufficient dispersion), the rotational speed of the stirrer 4 is automatically switched to a low speed, the peripheral speed of the stirring blade is reduced to 1 m/Se, and then the timer is set in advance for a time T (approximately 90 seconds) Continue stirring. In this way, high-speed stirring is performed for a short period of time during the initial stage when the thickener is introduced and dispersed, but after that, switching to low-speed stirring is performed.
To smoothly and uniformly dissolve a powder thickener in a short time without cutting the powder molecules of a powder thickening agent dispersed in water, that is, without causing a decrease in viscosity. The thickener added into the stirring tank 1 is now in the hydrophobic zone (Mamaco).
This greatly reduces the occurrence of albumen-like (glue-like) formation that causes viscosity non-uniformity, and it becomes possible to uniformly disperse and dissolve in water without causing a decrease in viscosity. Also, during the stirring operation described above, the cage-shaped strainer 16 in the tank 1 is activated by the vibrator 8.
By continuing to vibrate and vibrate, the hydrophobic band (mamako) and glue-like substances attached to the strainer 16 are dispersed and passed through, thereby further dispersing and dissolving the thickener in water. Let it grow further. In this way, when the set time of the timer comes, the stirring machine 5 and the vibrator 8 stop stirring, and the work of dissolving the thickener is completed.

If the level sensor LS3 confirms that the aqueous solution in the storage tank 2 is insufficient to a predetermined amount, the lift pump 9a of the lift pipe mechanism 9 is activated.
The aqueous thickener solution in the stirring tank 1 is sucked in from below the bottom of the strainer 16 and transferred into the storage tank 2. As a result, the water level of the aqueous solution in the storage tank 1 decreases, and the liquid level is detected by both level sensors LS1 and LS2.
The water pump 9a is stopped by a confirmation signal that the remaining amount of the aqueous solution in the tank has become below a predetermined level. Note that while the water pump 9a is in operation, the air valve 10a of the air blowing mechanism 10 opens in synchronization with this and injects GINIT air, and even though the water level in the tank 1 is decreasing, the level sensor 10a is opened. Hydrophobic bands and glue-like substances that remain attached to the probes of LSl and LS2 and cause malfunction of the sensors LS and LS2 are blown away with the above Ginnit Air, and the level sensor LS
1, so that LS2 can perform error-free detection operation according to the water level in tank 1. The thickener aqueous solution placed in the storage tank 2 is sucked by the pressure pump 11a of the supply pipe mechanism 11, which operates in conjunction with the operation of the concrete spraying machine, and is sprayed at the tip of the transfer pipe of the concrete spraying machine. It is added to dry mix concrete near the nozzle to reduce dust generation and rebound caused by concrete spraying.

Further, after the aqueous solution in the stirring tank 1 is transferred to the storage tank 2, the water supply pipe mechanism 3, stirrer 5, vibrator 8, feeder 14, etc. are sequentially operated in the same manner as described above when the preset counter 1 is reset. It operates and dissolves the thickener in exactly the same manner as above, waits until the remaining amount of the aqueous solution in the storage tank 2 becomes small, and then continuously supplies the thickener aqueous solution to the concrete spraying machine. Make it possible. Since this invention has been made as detailed above, it is possible to uniformly disperse and dissolve the thickener in water very easily and appropriately, and in a short period of time, so that it can be used at concrete spraying sites such as inside roads. It is very effective for use.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic diagram of the configuration of the device, and FIG. 2 is a time chart of the same device. 1... Stirring tank, 2... Storage tank, 3... Water supply mechanism, 3a... Water valve, 4... Thickener Quantitative supply mechanism (feeder 1), 5... Stirrer, 6... Strainer 1, 7... Elastic support, 8... Vibrator, 9. ...Pumping mechanism, 9a...
Lifting pump, 10... Air blowing mechanism, 10a
... Air valve, 11 ... Aqueous water supply pipe mechanism, 11a ... Pressure pump, LSL, L
S2, LS3...Liquid level sensor.

Claims (1)

[Claims] 1. A predetermined amount of water is placed in a stirring tank, a vortex is created in the water by high-speed rotation of a stirrer, and in this state, a water-soluble thermoplastic resin in the form of powder or granules is poured from above the water surface. A thickener characterized in that the thickener is dispersed in water while being added little by little, and after a predetermined amount of the thickener has been added and dispersed, the agitator is rotated at a low speed and stirring is continued for a predetermined period of time to dissolve the thickener. How to dissolve. 2. A stirring tank, a water supply pipe mechanism that supplies a predetermined amount of water into the stirring tank, and a small amount of a predetermined amount of a thickener made of a powdered or granular water-soluble thermoplastic resin from above the water surface in the stirring tank. It has a thickening agent quantitative supply mechanism that allows the thickener to be added at once, and when the thickener is added, it rotates at high speed to create a vortex in the water in the stirring tank, and after the thickener has been added and dispersed into the water, it rotates at a low speed. A thickener dissolving device comprising a variable speed stirrer that switches and operates for a predetermined period of time. 3. The thickener dissolving device according to claim 2, wherein the stirring tank has a cage-shaped strainer inside thereof that can be vibrated by a vibrator.