Low dust continuous mixing system

Abstract

To provide a compact system that can suppress scattering of powder to the outside and can efficiently and continuously perform a mixing process during the time between the entry of powder and the finish of mixing.SOLUTION: The dust-reducing continuous mixing system includes: powder storage means 12 that can store powder from a powder entry port 12A and can discharge the powder from a powder discharge port; lateral powder transport means 14 that is provided under the powder discharge port of the powder storage means and transports the powder discharged from the powder discharge port in the horizontal direction; longitudinal powder transport means 16 that is provided so that the axis line is approximately perpendicular to the axis line of the lateral powder transport means and transports upward the powder transported from the lateral powder transport means; mixing means 18 that mixes the powder transported from the longitudinal powder transport means and liquid; and dust collecting means 20 that sucks the powder scattering from the powder entry port to the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a low-dust continuous mixing system. [Background technology]

[0002] BACKGROUND ART Powders that require mixing, such as cement, mortar, concrete, and earthen materials, have conventionally been mixed with water in a predetermined ratio and kneaded using a mixer before use.

[0003] This type of mixing is often carried out near the construction site. For example, to produce cement milk from cement near the construction site, cement and water are often placed in a large plastic bucket and mixed manually using a mixer such as a hand mixer. Also, at small construction sites where working space is limited, it has been necessary to avoid installing a cement silo and instead have workers lift the cement bag and pour the cement directly into the mixer.

[0004] However, with this method, when the cement is poured from the cement bag, the powder is blown up, generating a large amount of dust, which causes problems such as dust pollution for workers. There is also concern about the danger caused by the rotation of the mixer blades when pouring.

[0005] In particular, replacing the concrete trackbed of railway tracks cannot be done during railway operating hours and must be done during limited hours late at night. Furthermore, the presence of overhead wires and supports surrounding the tracks limits the space available for installing equipment, making it difficult to carry out work efficiently in terms of both work efficiency and work content.

[0006] Patent Document 1 proposes a method for converting the ballast bed of a railway track into a concrete ballast bed in a rational and economical manner, in which an ultra-rapid-hardening, non-shrinkage grout mortar containing a rapid-hardening material and an expansive material is injected into the ballast bed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-87302 Summary of the Invention [Problem to be solved by the invention]

[0008] However, there is no mention of the large amount of dust that is generated when pouring cement from a cement bag, and of compact continuous processing at work sites where working space is limited.

[0009] In view of the above, an object of the present invention is to provide a compact system that can suppress the scattering of powder to the outside from the time the powder is added until the end of kneading, and that can perform efficient, continuous kneading processing. [Means for solving the problem]

[0010] The present inventors have conducted various studies to solve the above problems and have found that the problems can be solved by the present invention described below.

[0011] A low-dust continuous mixing system according to one embodiment of the present invention (this embodiment) includes: a powder storage means capable of storing powder from a powder inlet and discharging the powder from a powder outlet; a lateral feed powder conveying means arranged below the powder outlet of the powder storage means and conveying the powder discharged from the powder outlet in a horizontal direction; a vertical feed powder conveying means arranged so that its axis is approximately perpendicular to the axis of the lateral feed powder conveying means and conveys the powder conveyed from the lateral feed powder conveying means upward; a kneading means for kneading the powder conveyed from the vertical feed powder conveying means with a liquid; and a dust collection means for sucking up the powder scattering to the outside from the powder inlet.

[0012] By using a dust collection means to suck up the powder that scatters from the powder inlet, it is possible to reduce dust. In addition, by combining a horizontal powder conveying means with a vertical powder conveying means that is almost perpendicular to it, a compact system is possible. As a result, it is possible to suppress the scattering of powder to the outside from the time the powder is introduced until the end of kneading, and it is possible to provide a compact system that allows for efficient continuous kneading processing.

[0013] In the low-dust continuous kneading system of this embodiment, it is preferable that the powder storage means, the lateral powder conveying means, and the vertical powder conveying means are housed in a single server tank. By housing these in a single server tank, the server tank can be configured to be movable on a cart.

[0014] In the low-dust continuous kneading system of this embodiment, the shortest distance between the suction port of the dust collection means and the powder inlet is preferably 200 to 1000 mm. By keeping the distance within this range, it is possible to prevent the powder from scattering to the outside when dust is generated. The suction port of the dust collection means refers to, for example, the end of a dust collection duct.

[0015] In the low-dust continuous kneading system of this embodiment, it is preferable that the dust collecting means sucks up the powder that scatters when the powder is transported from the vertical powder transport means to the kneading means. By sucking up the dust before the kneading means, it is possible to further reduce dust in the entire system.

[0016] The low-dust continuous kneading system of this embodiment has an axial length (L A ) is 3000 to 6000 mm, and the axial length of the vertical powder conveying means (L B ) is preferably 1500 to 2500 m.

[0017] The low-dust continuous kneading system of this embodiment has an axial length (L A ) the axial length of the vertical powder conveying means (L B ) ratio (L B / L A ) is preferably 0.25 to 0.65.

[0018] In the low-dust continuous kneading system of this embodiment, the powder storage means is a hopper, and the taper angle of the lower part of the hopper is preferably 50 to 70°. By setting the taper angle of the lower part of the hopper to 50 to 70°, the powder is less likely to remain, and the powder is more likely to be smoothly supplied to the transverse powder conveying means.

[0019] In the low-dust continuous kneading system of this embodiment, it is preferable that the transverse powder conveying means is a transverse screw conveyor and the vertical powder conveying means is a vertical screw conveyor. By using screw conveyors for both the transverse powder conveying means and the vertical powder conveying means, the dispersibility and mixability of the powder can be improved.

[0020] In the low-dust continuous kneading system of this embodiment, it is preferable that at least one of the screws of the horizontal feed screw conveyor and the screws of the vertical feed screw conveyor is surface-treated. By applying the surface treatment, clogging of the powder can be prevented.

[0021] In the low-dust continuous kneading system of this embodiment, it is preferable that the blade shape of at least one of the screws of the horizontal feed screw conveyor and the vertical feed screw conveyor is a standard type with a standard pitch. By using such a blade shape, clogging of the powder can be prevented.

[0022] The low-dust continuous kneading system of this embodiment preferably further comprises an additional kneading means, and the powder discharged from the kneading means is kneaded again by the additional kneading means, thereby enabling a stable supply of the kneaded product.

[0023] In the low-dust continuous kneading system of this embodiment, the height of the vertical powder conveying means is preferably 1000 to 2150 mm, which allows it to be used sufficiently even in tunnels and the like that have height restrictions.

[0024] In the low-dust continuous kneading system of this embodiment, the height of the server tank is preferably 1000 to 1900 mm, which allows it to be used sufficiently even in tunnels and the like that have height restrictions.

[0025] In the low-dust continuous mixing system of this embodiment, the powder is preferably a mortar raw material powder. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a compact system that can suppress the scattering of powder to the outside from the time the powder is added until the end of kneading, and that can perform efficient, continuous kneading processing. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a side view of a low-dust continuous mixing system according to one embodiment of the present invention. FIG. [Figure 2] 2 is a cross-sectional view of the low-dust continuous kneading system shown in FIG. 1 along the line AA. [Figure 3] 1 is a plan view of a portion of a low-dust continuous kneading system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] This embodiment will be described in detail below. 1, the low-dust continuous kneading system according to this embodiment includes powder storage means 12 that stores powder through powder inlet 12A and can discharge the powder through a powder outlet, transverse powder conveying means 14 that is disposed below the powder outlet of powder storage means 12 and conveys the powder discharged from the powder outlet in a horizontal direction, vertical powder conveying means 16 that is disposed with an axis that is substantially perpendicular to the axis of transverse powder conveying means 14 and conveys the powder conveyed from transverse powder conveying means 14 upward, kneading means 18 that kneads the powder conveyed from vertical powder conveying means 16 with a liquid, and dust collection means 20 that sucks up powder that scatters from the powder inlet to the outside. Here, "substantially perpendicular" refers to an angle of approximately 90°±10° relative to the axis of transverse powder conveying means 14, and is preferably perpendicular.

[0029] For example, in a conventional mixer with limited workspace, workers had to open a cement bag and pour cement directly into the mixer. This resulted in large amounts of dust being generated, creating problems such as dust pollution for workers. However, in this embodiment, dust is reduced by using a dust collection device to suck up the powder scattered from the powder inlet. Furthermore, a compact system can be realized by combining a horizontal powder conveying device with a vertical powder conveying device that is approximately perpendicular to the horizontal powder conveying device. As a result, powder scattering from the time the powder is introduced until the end of mixing is suppressed, enabling efficient, continuous mixing and kneading. Furthermore, a compact system that can be used in a limited workspace can be provided.

[0030] Powder containing means 12 is a powder containing tank that contains powder through a powder inlet 12A and is configured so that the contained powder can be discharged from a powder outlet located at the bottom thereof to lateral feed powder conveying means 14. There are no particular limitations on the shape of powder containing means 12 as long as it tapers from the powder inlet 12A side towards the powder outlet at the bottom, but a hopper is preferred.

[0031] When the powder containing means 12 is a hopper, as shown in FIG. 2, which is a cross section taken along line AA in FIG. 1, the angle of inclination of the lower inclined portion of the hopper, as the angle (θ) between the horizontal line and the inclined portion of the lower inclined portion of the hopper, is preferably 50 to 70°, and more preferably 55 to 65°.

[0032] The lateral powder conveying means 14 is connected to the powder discharge port of the powder storage means 12, and conveys the powder dropping from the powder discharge port to the vertical powder conveying means 16. The lateral powder conveying means 14 may, for example, have a cylindrical trough (casing) and a rotating shaft provided with screw blades, with the rotating shaft inserted into the trough, and is preferably a lateral screw conveyor. A motor with a reducer is provided at the end of the rotating shaft (the end opposite the vertical feed powder conveying means), and when this motor is operated to rotate the rotating shaft, the powder is displaced by the screw blades of the rotating shaft and gradually moves axially within the trough toward the vertical feed powder conveying means 16. The top of the trough may be entirely open, or may be partially open and the open part may be connected to the powder discharge port of the powder containing means 12 .

[0033] From the viewpoint of compacting the system, the length in the axial direction of the transverse powder conveying means 14 (L A ) is preferably 3000 to 5000 mm, more preferably 3000 to 4500 mm. The outer diameter of the trough of the transverse powder conveying means 14 is preferably about 150 to 250 mm. The outer diameter of the screw blade of the transverse powder conveying means 14 is preferably about 165 to 235 mm, which is large enough to be accommodated in the trough. The screw pitch of the screw blade is preferably about 120 to 235 mm. The shape of the screw blade is preferably a standard pitch or a variable pitch, and more preferably a standard type with a standard pitch.

[0034] The screw rotation speed when rotating the rotary shaft is preferably about 35 to 60 rpm.

[0035] The vertical feed powder conveying means 16, for example, has a rotating shaft with a screw blade disposed inside a cylinder, and the upper part of the rotating shaft is connected to a motor for rotation. The side of the cylinder at the lower part of the vertical feed powder conveying means 16 is connected to the end of the trough of the horizontal feed powder conveying means 14, and the powder conveyed from the horizontal feed powder conveying means 14 is sent to the lower part of the vertical feed powder conveying means 16, conveyed to the upper part by the vertical feed powder conveying means 16, and then conveyed to the kneading means 18 through a conveying pipe 22 connected to an outlet at the upper part. The vertical feed powder conveying means 16 is preferably a vertical feed screw conveyor.

[0036] From the viewpoint of compacting the system, the length in the axial direction of the vertical powder conveying means 16 (L B ) is preferably 1500 to 2500 mm, and more preferably 1800 to 2300 mm. The outer diameter of the cylindrical body of the vertical feeding powder conveying means 16 is preferably about 130 to 220 mm. The outer diameter of the screw blade of the vertical powder conveying means 16 is preferably about 155 to 205 mm so that it can be housed in the cylindrical body. The screw pitch of the screw blade is preferably about 120 to 200 mm. The shape of the screw blade is preferably a standard pitch or a variable pitch, and more preferably a standard type with a standard pitch.

[0037] The screw rotation speed when rotating the rotary shaft is preferably about 200 to 380 rpm.

[0038] Here, the length (L A ) relative to the axial length (L B ) ratio (L B / L A) is preferably 0.25 to 0.65, and more preferably 0.35 to 0.5. By keeping this ratio within the above range, the length of the axial direction of the lateral feed powder conveying means in particular does not become too long, and the functions of the lateral feed powder conveying means and the vertical feed powder conveying means can each be efficiently exhibited.

[0039] It is also preferable that at least one of the screws of the horizontal screw conveyor and the vertical screw conveyor is surface-treated. This surface treatment can prevent clogging with powder (mortar, etc.). Examples of surface treatments include Teflon (registered trademark) treatment.

[0040] The kneading means 18 is not particularly limited as long as it has a kneading section, but for example, it preferably has a storage chamber that temporarily stores the powder transported from the upper part of the vertical feed powder transport means 16 and a kneading section that kneads the powder in the storage chamber. An example of the storage chamber is a hopper, and examples of the kneading means with a kneading section include kneading mixers such as grout mixers, high-speed hand mixers, and forced stirring mixers. In the kneading section, a liquid (for example, water) is supplied for kneading with the powder.

[0041] After mixing, the mixture is injected into an appropriate location at the construction site from a discharge port provided in the mixing section by a pressure pump.

[0042] From the viewpoint of compacting the system, when the powder storage means 12, the lateral feeding powder conveying means 14, the longitudinal feeding powder conveying means 16, and the dust collecting means 20 are viewed in a plan view, as shown in FIG. 3, the length in the axial direction of the lateral feeding powder conveying means 14 (L C ) is preferably 3000 to 5000 mm. D ) is preferably 700 to 1200 mm. By setting each length within the above range, it is possible to accommodate it in places where the working space is restricted, such as a tunnel in the ballast bed of a railway track, and effective construction is possible.

[0043] It is also preferable that the powder storage means 12, the horizontally feeding powder conveying means 14, and the vertically feeding powder conveying means 16 are housed in one server tank. Furthermore, the height of the vertical powder conveying means 16 is preferably 1000 to 2150 mm, and the height of the server tank is preferably 1000 to 1900 mm. By setting the respective heights within the above ranges, they can be accommodated in places where there are restrictions on the working space, such as tunnels on the ballast bed of railway tracks, enabling effective construction.

[0044] Furthermore, powder inlet 12A of powder containing means 12 is preferably at a height of 2 mm or less from the bottom of powder containing means 12. A height of 2 mm or less improves workability.

[0045] In the present invention, dust collecting means 20 is provided to suck up powder scattered to the outside from powder inlet 12A. As the dust collecting means 20, a known dust collecting device can be used. The shortest distance between the suction port of the dust collecting means 20 and the powder inlet 12A is preferably 200 to 1000 mm, more preferably 350 to 600 mm. Here, the suction port of the dust collecting means refers to, for example, the end 20A of the dust collecting duct.

[0046] Furthermore, it is preferable that the powder that scatters when being conveyed from the vertical feed powder conveying means 16 to the kneading means 18 is sucked up by the dust collecting means 20. For example, it is preferable that the dust before the kneading means 18 is sucked up by a dust collecting hose connected to the dust collecting means 20, for example, the end 20B of a dust collecting duct. By sucking up the dust before the kneading means, it is possible to further reduce dust in the entire system.

[0047] The low-dust continuous kneading system of the present invention preferably further comprises additional kneading means 24. In the additional kneading means 24, the powder-containing kneaded material is supplied from the discharge port of the kneading section of the kneading means 18 through a hose 23 and kneaded again. The kneaded material is then fed to an appropriate location at the construction site through a hose 26. This allows for an even more stable supply of the kneaded material. Here, the additional kneading means 24 may be an after-mixer (a remixer of G-MIX) or the like.

[0048] Powders to be used in the low-dust continuous mixing system according to this embodiment include cement, mortar, concrete, earthen materials, and other powders that require mixing, and mortar raw material powders including mortar are preferred.

[0049] For use in railway track ballast beds, it is preferable that the mortar raw material powder contains a rapid-hardening additive and an expansive additive. The rapid-hardening additive is composed of crystalline or amorphous calcium aluminate and gypsum such as anhydrous gypsum, hemihydrate gypsum, or dihydrate gypsum, and produces ettringite through a hydration reaction. The amount of the rapid-hardening additive used is preferably 5 to 50 parts by mass, more preferably 20 to 40 parts by mass, per 100 parts by mass of cement. If the amount is less than 5 parts by mass, it is difficult to obtain the effects of the present invention, such as difficulty in obtaining strength in a short period of time, and if the amount exceeds 50 parts by mass, the effects cannot be expected.

[0050] The expansive agent is composed of calcium sulfoaluminate containing free lime and having a mineral composition represented by the formula 3CaO·3Al2O3·CaSO4 (C3A3CaSO4), and can form ettringite upon hydration, or it can be a quicklime (CaO)-based agent that forms Ca(OH)2 upon hydration. The amount of expansive agent used is preferably 1 to 10 parts by mass, more preferably 3 to 8 parts by mass, per 100 parts by mass of cement. If it is less than 1 part by mass, the expansion will be too small, and if it exceeds 10 parts by mass, the expansion will be too large, which may cause destruction.

[0051] Furthermore, in order to increase the fluidity, it is possible to use at least one admixture such as a water-reducing agent, a high-performance water-reducing agent, a high-performance air-entraining water-reducing agent, and a superplasticizer. Cements used in ultra-fast-hardening non-shrinkage grout mortar include various Portland cements such as normal, early-strength, and extra-early-strength, and various blended cements that contain fly ash or blast furnace slag in addition to these Portland cements, and generally normal, early-strength, or extra-early-strength Portland cement is used.

[0052] In this embodiment, it is preferable to prepare an ultra-rapid-hardening non-shrink grout mortar by kneading ultra-rapid-hardening cement, which is made of cement, a rapid-hardening material, and an expansive material, with sand and water in a mixer as the mortar raw material powder. The cement / sand ratio, which is the ratio of cement to fine aggregate in ultra-fast-hardening non-shrink grout mortar, is usually 1 / 0.5 to 1 / 3, and the water / binder ratio, which is the ratio of water to the binder consisting of cement, fast-hardening material, and expansive material, can be changed depending on external factors such as air temperature and water temperature, and the required target softness. It is also preferable to add a set retarder to adjust the handling time (workable time) of the ultra-fast hardening non-shrink grout mortar.

[0053] The low-dust continuous mixing system of the present invention is preferably mounted on a carriage. Mounting it on a carriage makes it movable, improving convenience. By using a carriage that is applicable to railway tracks, it can be used to replace the concrete trackbed of railway tracks. In other words, it can be a low-dust continuous mixing system for replacing the concrete trackbed of railway tracks. The mounting surface of the carriage is a rectangular area (L 1 ) as shown in FIG. 3, in which the powder storage means 12, the horizontal powder conveying means 14, the vertical powder conveying means 16, and the dust collecting means 20 are installed. C ×L D ) is preferably included.

[0054] [Test example] A low-dust continuous mixing system as shown in Figure 1 was fabricated and a mixing test was carried out. An outline of the system is shown in Table 1 below. The powder used was Hypretascon TYPE-1S for prepacked construction (manufactured by Denka Co., Ltd.). The water / powder ratio (%) was set to 20%.

[0055] [Table 1]

[0056] The amount of dust from the start of operation of the system was measured using a commercially available dust collector. The results are shown in Table 2 below.

[0057] [Table 2]

[0058] As a result of this test, the following was confirmed. (1) The low-dust continuous mixing system was stable in both powder supply and fluidity of the discharged mortar. (2) For low-dust continuous mixing, the dust concentration before the test was 0.020 mg / m when materials were fed from the flexible container to the hopper and when materials were fed from the hopper to the mixer during operation. 3 0.026 to 0.030 mg / m at each location 3 The amount was about the same as above, and almost no dust generation was observed. On the other hand, the conventional method of pouring open bags resulted in a concentration of 3.26 mg / m at each location during the pouring process. 3 ~6.47mg / m 3 A lot of dust was generated. 3 The amount of dust remained, which was greater than during low-dust continuous mixing. From this, it is believed that by using low-dust continuous mixing in construction work, dust generation can be significantly reduced, and furthermore, since opening bags to load materials becomes unnecessary, the burden on workers can also be reduced. [Industrial Applicability]

[0059] The low-dust continuous mixing system of the present invention can be suitably applied to construction work on railway tracks in operation, mainly during nighttime periods when the tracks are out of service, from the last train to the first train. [Explanation of symbols]

[0060] 12 Powder containing means 12A Powder inlet 14 Powder conveying means 16 Vertical powder conveying means 18 Mixing means 20 Dust collection means

Claims

1. a powder containing means capable of containing powder through a powder inlet and discharging the powder through a powder outlet; a lateral powder conveying means disposed below the powder discharge port of the powder containing means and configured to convey the powder discharged from the powder discharge port in a horizontal direction; a vertical powder conveying means provided so as to have an axis substantially perpendicular to the axis of the horizontal powder conveying means, for conveying the powder conveyed from the horizontal powder conveying means upward; a kneading means for kneading the powder and liquid conveyed from the vertical powder conveying means; a dust collecting means for sucking the powder scattered to the outside from the powder inlet; Including, the powder storage means, the lateral feeding powder transport means, and the vertical feeding powder transport means are housed in a single server tank, a side surface of the cylindrical body at a lower portion of the vertical feeding powder conveying means is connected to an end portion of the trough of the horizontal feeding powder conveying means; The powder is any one of cement, mortar, concrete, soil material, and mortar raw material powder containing the mortar, the horizontal powder conveying means is a horizontal screw conveyor, and the vertical powder conveying means is a vertical screw conveyor, At least one of the screws of the horizontal feed screw conveyor and the screws of the vertical feed screw conveyor is surface-treated to prevent clogging of the powder, A low-dust continuous mixing system for railway track ballast beds.

2. 2. The low-dust continuous kneading system according to claim 1, wherein the shortest distance between the suction port of the dust collecting means and the powder inlet is 200 to 1,000 mm.

3. 3. The low-dust continuous kneading system according to claim 1, wherein the dust collecting means sucks in the powder that scatters when the powder is transported from the vertical powder transport means to the kneading means.

4. The length in the axial direction of the transverse powder conveying means (L Ａ ) is 3000 to 5000 mm, and the axial length of the vertical powder conveying means (L Ｂ 4. The low-dust continuous kneading system according to claim 1, wherein the distance between the nozzle and the nozzle is 1500 to 2500 mm.

5. The length in the axial direction of the transverse powder conveying means (L Ａ ) relative to the axial length of the vertical powder conveying means (L Ｂ ) ratio (L Ｂ / L Ａ 5. The low-dust continuous kneading system according to claim 1, wherein the ratio of the total mass of the mixture to the total mass of the kneading material is 0.25 to 0.

65.

6. 6. A low-dust continuous kneading system according to claim 1, wherein the powder containing means is a hopper, and the taper angle of the lower part of the hopper is 50 to 70 degrees.

7. The shape of the blades of at least one of the screws of the horizontal feed screw conveyor and the vertical feed screw conveyor is a standard type with a standard pitch, The screw rotation speed when rotating the rotation shaft of the transverse screw conveyor is 35 to 60 rpm, 7. The low-dust continuous kneading system according to claim 1, wherein the screw rotation speed when rotating the rotation shaft of the vertical feed screw conveyor is 200 to 380 rpm.

8. 8. The low-dust continuous kneading system according to claim 1, further comprising an additional kneading means, wherein the powder discharged from the kneading means is kneaded again by the additional kneading means.

9. The low-dust continuous kneading system according to any one of claims 1 to 8, wherein the height of the vertical powder conveying means is 1000 to 2150 mm.

10. The low-dust continuous kneading system according to any one of claims 1 to 8, wherein the height of the server tank is 1000 to 1900 mm.

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