Cavity repair method and injection equipment for cavity repair

Abstract

To provide a cavity repair method and an injection device for cavity repair capable of filling foam polyurethane excellent in quality.SOLUTION: A repair method comprises steps of: connecting a first pipe 21 from a first tank 1 for a polyol component and a second pipe 41 from a second tank 3 for an isocyanate component to a high pressure mixing machine 5; mixing in high pressure and reacting polyol component mixed liquid 1a and isocyanate component mixed liquid 3a in the high pressure mixing machine 5 after connecting the high pressure mixing machine 5 and a nozzle 7 a tip of which is placed in a cavity C to be filled with hard urethane foam with a hose 61, as well as injecting pressured air in the hose 61 at a downstream side from the high pressure mixing machine 5; discharging reaction-progressed foam material from the nozzle 7; and filling the cavity C with the hard urethane foam in a hard foam state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cavity repair method for filling cavities that occur behind a tunnel lining or in the ground of a building, and to an injection facility for cavity repair. [Background technology]

[0002] For example, a cavity C, as shown in Figure 8, may occur between a tunnel's lining concrete R and the natural ground S behind it. When such a cavity is formed, it is thought that an unbalanced load will be applied locally, causing deformation. Therefore, injection devices and methods have been proposed that inject an agent into the cavity C, fill it with the agent's filler material, and eliminate the unbalanced load (for example, Patent Document 1). Cavities can also form in the ground beneath a building due to groundwater flow, etc., and since there is a risk of the building tilting, the same treatment is used as in the case of cavity C in the lining concrete R above. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6360922 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] As described in claim 1 of Patent Document 1, the invention relates to an injection device that "includes a main agent feed pipe connected at its base end to a main tube connected at its base end to a main pressure pump that pressurizes and delivers the hardening agent and connected at its tip to an injection pipe inserted into the cavity; an air inlet pipe airtightly connected to a connector provided in the wall of the main agent feed pipe, which introduces compressed air from an air compressor into the main agent feed pipe to feed the hardening agent into the injection pipe while stirring it; and a pressure sensor connected to the air inlet pipe that measures the pressure of the compressed air..." Furthermore, paragraph 0005 of the patent also states, "Among these, foamed polyurethane has the advantage of being lightweight and foaming simply by mixing the raw material liquid at the construction site, expanding to several to several tens of times its volume, hardening, and filling the cavity." The detailed description of the invention also exclusively refers to foamed polyurethane.

[0005] However, as paragraph 0056 of Patent Document 1 states, "This compressed air, the polyol compound, and the blowing agent-containing liquid impinge and mix before reaching the tip port 11e1, thereby preparing a foamed polyurethane raw material liquid containing a large amount of air," a large amount of mixing compressed air must be supplied, even though it is not necessary for the urethane reaction itself. On the other hand, when using a high-pressure foaming machine such as that disclosed in JP-A-58-108497, the flow rate of the foamed polyurethane raw material liquid increases with increasing pressure, resulting in increased resistance to flow. To reduce resistance to flow, the high-pressure foaming machine must be connected directly or at a distance close enough to a nozzle attached to the lining concrete with its tip positioned within the cavity. Furthermore, in conventional injection devices such as those described in Patent Document 1, filling a cavity with urethane raw materials can be hindered by the presence of water W in cavity C, as shown in Figure 9. While paragraph 0005 of Patent Document 1 states that "foaming occurs simply by mixing the raw material liquids," it takes time for the polyol component and the isocyanate component to react and become a cream-like substance with a specific gravity of less than 1.0, even if they are thoroughly mixed. If water W is present in cavity C and this water comes into contact with the urethane reaction fluid, it will react with the water, increasing the foaming ratio and causing the density and strength to deviate from the specifications. Before foamed polyurethane turns into a cream, the urethane raw material has a specific gravity of 1.21, which is heavier than water. When it comes into contact with water in this state, it sinks, then foams, causing its specific gravity to fall below 1.0 and it floats up. However, this increases the contact area with water, which can lead to the problem of increased abnormal foaming.

[0006] The present invention solves the above problems by providing a cavity repair method and injection equipment that employs a high-pressure agitator that does not require a large amount of air, while allowing for a sufficient connection distance between the agitator and the nozzle, and that, when the urethane raw material is injected into the cavity, is able to fill the cavity with high-quality foamed polyurethane without causing any problems even if water accumulates in the cavity. [Means for solving the problem]

[0007] In order to achieve the above object, the gist of the invention described in claim 1 is a cavity repair method characterized by connecting a first pipe from a first tank for a polyol component and a second pipe from a second tank for an isocyanate component to a high-pressure agitator, and connecting the high-pressure agitator to a nozzle whose tip is placed in the cavity to be filled with rigid foamed urethane with a hose, then high-pressure mixing the polyol component compound liquid and the isocyanate component compound liquid in the high-pressure agitator to cause them to react, while injecting air into the hose downstream of the high-pressure agitator, discharging the foamed raw material from the nozzle as the reaction progresses, and then filling the cavity with the foamed and hardened rigid foamed urethane. The gist of the invention described in claim 2 is a cavity repair method comprising: connecting a first pipe from a first tank for a polyol component and a second pipe from a second tank for an isocyanate component to a high-pressure agitator; connecting the high-pressure agitator to a nozzle whose tip is placed in the cavity to be filled with rigid foamed urethane with a hose; mixing the polyol component liquid mixture and the isocyanate component liquid mixture under high pressure in the high-pressure agitator to cause a reaction; injecting air into the hose downstream of the high-pressure agitator to cause the reaction to proceed as the mixture passes through the hose; discharging the mixture as a cream-like substance having a specific gravity of less than 1 from the tip of the nozzle; and then filling the cavity with the foamed and hardened rigid foamed urethane. The cavity repair method of claim 3 is the same as claim 1 or 2, characterized in that the polyol component liquid mixture and the isocyanate component liquid mixture are mixed under high pressure in the high-pressure agitator, a pressure gauge for measuring the pressure of the reaction fluid between the polyol component and the isocyanate component flowing through the hose is attached downstream of the high-pressure agitator, and then the polyol component liquid mixture and the isocyanate component liquid mixture are mixed under high pressure in the high-pressure agitator to cause a reaction.The cavity repair method of claim 4 is the same as claim 1, characterized in that the high-pressure agitator and the nozzle are connected by the hose, the polyol component liquid mixture passing through the first piping is heated by a first heater and the isocyanate component liquid mixture passing through the second piping is heated by a second heater, and then the polyol component liquid mixture and the isocyanate component liquid mixture are mixed under high pressure in the high-pressure agitator to cause a reaction. The gist of the invention described in claim 5 is an injection system for cavity repair comprising: a high-pressure agitator having one end of a first pipe connected to a first tank for a polyol component and the other end of a second pipe connected to one end of a second tank for an isocyanate component; a hose connecting the high-pressure agitator to a nozzle whose tip is placed in the cavity to be filled with rigid urethane foam; and an air pipe connected to the hose downstream of the high-pressure agitator; wherein a polyol component compound liquid and an isocyanate component compound liquid are mixed under high pressure in the high-pressure agitator, the polyol component and the isocyanate component react with each other, and the foaming raw material as the reaction progresses is discharged from the nozzle, and the rigid urethane foam is foamed and hardened. The gist of the invention described in claim 6 is an injection system for cavity repair comprising: a high-pressure agitator having one end of a first pipe connected to a first tank for a polyol component and the other end of a second pipe connected to a second tank for an isocyanate component; a hose connecting the high-pressure agitator to a nozzle whose tip is placed in the cavity to be filled with rigid foamed urethane; and an air pipe connected to the hose downstream of the high-pressure agitator, wherein the total length of the hose and the nozzle is set so that the polyol component compound liquid and the isocyanate component compound liquid are mixed under high pressure within the high-pressure agitator, the polyol component and the isocyanate component react with each other, and are discharged from the tip of the nozzle as a cream-like substance with a specific gravity of less than 1. The cavity repair injection equipment of the invention of claim 7 is characterized in that the polyol component compound liquid and the isocyanate component compound liquid are mixed under high pressure in the high-pressure agitator, and a pressure gauge for measuring the pressure of the reaction proceeding fluid between the polyol component and the isocyanate component flowing in the hose is attached downstream of the high-pressure agitator.The cavity repair injection equipment of the invention of claim 8 is characterized in that the cavity repair injection equipment of the invention of claims 5 to 7 further includes a first heater for heating the polyol component compound liquid passing through a first piping, and a second heater for heating the isocyanate component compound liquid passing through the second piping. [Effects of the Invention]

[0008] The cavity repair method and cavity repair injection equipment of the present invention enable the use of a high-pressure agitator even when the high-pressure agitator and nozzle are connected by a hose, thereby enhancing the mixing effect, and furthermore, in response to the uncertainty of whether water has accumulated in the cavity, even if there is a puddle of water, it reduces contact between the foaming raw material of the foamed polyurethane and the water, thereby enabling the cavity to be filled with stable, good-quality foamed polyurethane, thereby demonstrating excellent effects. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic explanatory diagram showing one embodiment of the cavity repair method and cavity repair injection equipment of the present invention, the injection equipment. [Figure 2] FIG. 2 is a partially enlarged view of the cream-like substance reaching the water surface from the state shown in FIG. 1. [Figure 3] FIG. 3 is an enlarged partial view of the state of FIG. 2 in which the cream-like substance has filled the cavity. [Figure 4] FIG. 4 is an explanatory enlarged view showing the cream-like body pressing against the water surface from the state shown in FIG. 3. [Figure 5] This is an enlarged explanatory view showing the cavity filled with hard urethane foam after time has passed since FIG. 4. [Figure 6] FIG. 2 is an explanatory cross-sectional view of a mixing and stirring section of a high-pressure mixer. [Figure 7] FIG. 2 is an explanatory cross-sectional view of a mixing and stirring section of a high-pressure mixer. [Figure 8] This is an explanatory cross-sectional view showing a cavity occurring behind the lining concrete. [Figure 9] FIG. 9 is an explanatory cross-sectional view showing a puddle in the cavity of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0010] The cavity repair method and cavity repair injection equipment according to the present invention are described in detail below. Figures 1 to 7 show one embodiment of the cavity repair method and cavity repair injection equipment (hereinafter simply referred to as "injection equipment"). Figure 1 is an explanatory diagram of the injection equipment. Figure 2 is an enlarged view of the cream-like substance reaching the water surface from the state shown in Figure 1. Figure 3 is an enlarged view of the cream-like substance filling the cavity from the state shown in Figure 2. Figure 4 is an enlarged view of the cream-like substance pressing against the water surface from the state shown in Figure 3. Figure 5 is an enlarged view of the cavity being filled with rigid urethane foam after time has passed from Figure 4. Figures 6 and 7 show cross-sectional views of the mixing and stirring section of a high-pressure mixer. For clarity, each figure is simplified and the essential parts of the invention are emphasized. Portions not directly related to the present invention are omitted, and hatching indicating the cross section of the lining concrete R is omitted from each figure.

[0011] (1) Injection equipment for cavity repair The cavity repair injection equipment includes a first tank 1 for a polyol component, a second tank 3 for an isocyanate component, a first pipe 21, a second pipe 41, a high-pressure agitator 5, a hose 61, an air pipe 81, and a pressure gauge 62 for the reaction proceeding fluid (Figure 1).

[0012] The first tank 1 for polyol component is a heat-insulating tank that stores the polyol component compounded liquid 1a sent from a drum (not shown) at an appropriate temperature using a heater, etc. The second tank 3 for isocyanate component is a heat-insulating tank that stores the isocyanate component compounded liquid 3a sent from a drum (not shown) at an appropriate temperature using a heater, etc. The rigid urethane foam 93 filling the cavity C is formed from a polyol component liquid mixture 1a (hereinafter also referred to as "liquid A"), which is a liquid mixture containing a polyol component for two-component polyurethane resin, and an isocyanate component liquid mixture 3a (hereinafter also referred to as "liquid B") containing an isocyanate component. Liquid A comprises a polyol, such as a polyether polyol or a polyester polyol, or both, a catalyst, a blowing agent, etc. Liquid B comprises, for example, TDI prepolymer, crude TDI, polymeric MDI, various modified MDI, etc. Liquid A and liquid B are separately pumped by drum pumps into a first tank 1 and a second tank 3. Both liquids are sent from the first tank 1 and the second tank 3 through a first pipe 21 and a second pipe 41, respectively, to a high-pressure mixer 5.

[0013] The first pipe 21 is a pipe that connects the first tank 1 and the high-pressure agitator 5. One end of the first pipe 21 is connected to the lower part of the first tank 1, and the other end of the first pipe 21 is connected to the high-pressure agitator 5 via a high-pressure pump 25. The second pipe 41 is a pipe that connects the second tank 3 and the high-pressure agitator 5. One end of the second pipe 41 is connected to the lower part of the second tank 3, and the other end of the second pipe 41 is connected to the high-pressure agitator 5 via a high-pressure pump 45. Flow meters 29 and 49 are attached to the discharge sides of the high-pressure pumps 25 and 45 associated with the first and second pipes 21 and 41, respectively. The flow meters 29 and 49 display and record the instantaneous and cumulative flow rates of liquid A and liquid B passing through the pipes. A first heater 26 and a second heater 46 are installed in the first and second pipes 21 and 41 up to the vicinity of the flow meters 29 and 49. Specifically, a coil fin heater is installed, which is a sheathed heater made of nichrome wire wrapped in a metal pipe with an insulator between them and a spiral heat-dissipating flange called a coil fin wrapped around the surface of the sheathed heater. The coil fin heater is installed inside the first pipe 21 (or second pipe 41), improving thermal efficiency and heating liquid A (or liquid B). First and second hose heaters 22 and 42, each with a built-in heater wire, are installed in the first and second pipes 21 and 41 from the flow meters 29 and 49 to the high-pressure agitator 5. These heaters can adjust the temperatures of liquid A and liquid B flowing inside the pipes. The temperatures of liquid A and liquid B are adjusted by first and second heaters 26 and 46 and first and second hose heaters 22 and 42 wrapped around the first pipe 21 and second pipe 41 up to near the high-pressure agitator 5, but the first and second hose heaters 22 and 42 are not shown in Figures 2 and 3. Reference numerals 23 and 43 denote thermometers for measuring the temperatures of liquid A and liquid B, which are installed in the first and second pipes 21 and 41 just before they enter the high-pressure agitator 5. The first pipe 21 and the second pipe 41, which run from the flowmeters 29, 49 to the high-pressure mixer 5, are made of high-pressure tubes. The high-pressure tubes are flexible and supple, making it easy for workers to handle the pumps 25, 45, flowmeters 29, 49, and other equipment while they are still installed and fixed on the transport vehicle.

[0014] High-pressure agitators 5 are well known, but here, they act as injection guns that spray liquids A and B with high ejection energy from fine holes 510, 530 provided in the chamber inner wall 500, and mix and mix them by colliding with each other (Figure 6). While the low-pressure foam injection device described in Patent Document 1 pumps liquid A and liquid B from the first tank 1 and the second tank 3 at a pressure of 7 to 9 MPa, the high-pressure pump 25 of the first pipe 21 and the high-pressure pump 45 of the second pipe 41 pump liquid A and liquid B from the first tank 1 and the second tank 3 to the high-pressure agitator 5, respectively. Liquid A (liquid B) pumped to the high-pressure agitator 5 passes through the flow path 51 (53) of the mixing and stirring section 5b, which is the main section, and is sprayed under high pressure into the chamber 50 from the pores 510 (530) in the cylindrical inner wall 500. The pores 510 for liquid A and the pores 530 for liquid B are inclined in the cylindrical axial direction of the chamber 50, from the ring-shaped flow path that circles near the cylindrical inner wall 500 to the pore openings in the cylindrical inner wall 500, and liquid A and liquid B are discharged toward the opposing pore at this angle of inclination.

[0015] When the injection gun of the high-pressure mixer 5 is gripped by hand and the lever 5a in FIG. 1 is pulled, the rod 57 retracts as shown in FIG. 6, first opening the aperture 530, and liquid B is sprayed from the aperture 530, which serves as a liquid B outlet, into the cylindrical chamber 50. Further retraction of the rod 57 (substantially instantaneous) moves the rod head 571 back beyond the position of the aperture 510. The aperture 510 opens, and liquid A is ejected from the aperture 510, which serves as a liquid A outlet, toward the spraying liquid B. The collision of liquid A and liquid B results in efficient mixing and agitation. The agitated and mixed foaming raw material g passes through the hose 61 connected to the retaining cylindrical portion 56 of the chamber 50 and further through the nozzle 7 connected to the hose 61 to the nozzle tip opening 70. The injection equipment of the present invention is configured to perform high-pressure mixing in a high-pressure agitator 5, reacting the polyol component with the isocyanate component, and ensuring time for the reaction to proceed from the high-pressure agitator 5 through a long hose 61 to the tip opening 70 of the nozzle 7, and then eject a cream-like substance 91 with a specific gravity of less than 1 from the tip opening 70 of the nozzle. The "creamy substance" referred to here refers to a substance that has changed in appearance to a creamy substance as a result of the A liquid and the B liquid being stirred, mixed, and reacting, and incorporating air bubbles to form foam. In the present invention, this creamy substance 91, which has a specific gravity of less than 1, is discharged from the nozzle tip 70. The A liquid and the B liquid are mixed under high pressure using the high-pressure agitator 5, and are reacted in the hose 61 and the nozzle 7 until a creamy substance 91 with a specific gravity of less than 1 is formed.

[0016] The reaction-progressing fluid of foaming raw material g, that is, the creamy substance 91 in a desirable state with a specific gravity of less than 1, continues to be discharged from the nozzle tip opening 70, and after the required amount of creamy substance 91 has been discharged into cavity C, the hand pulling the lever 5a of the injection gun is released. Then, lever 5a returns to its original position, and rod 57 advances as shown by the outlined arrow in Figure 7, so that rod 57 closes the respective openings of fine hole 510 of the liquid A outlet and fine hole 530 of the liquid B outlet. Unlike manually opening and closing a valve, the start and stop of injection of liquid A and liquid B into cavity C can be quickly switched by simply pulling or releasing lever 5a. The structure of the mixing and stirring section 5b is not limited to the structure shown in Figs. 6 and 7, and may be configured, for example, as described in Japanese Patent No. 5126817, so that the liquid ejected from one of the multiple orifices crosses and collides with itself within the chamber before colliding with the liquid ejected from the other orifice, thereby further increasing the degree of mixing.

[0017] The hose 61 is a flexible pressure-resistant hose that connects the high-pressure agitator 5 and the nozzle 7. In cavity repair work to fill a cavity C behind the tunnel lining, the nozzle 7 is attached to the lining concrete R to inject foaming material g for rigid urethane foam into the cavity C. The nozzle 7 is fixed to the required location of the lining concrete R, with its tip positioned in the cavity C to be filled with rigid urethane foam 93 (Figures 1 to 3). After drilling a hole in the lining concrete R, the nozzle 7 is inserted and fixed to the lining concrete R with its base end protruding toward the tunnel interior TN. The hose 61 connects the nozzle 7 to the high-pressure agitator 5, and guides the reaction-progressing fluid of foaming material g, which is agitated and mixed with liquid A and liquid B by the high-pressure agitator 5, to the nozzle tip 70. Preferably, the reaction-progressing fluid of foaming material g is made into a cream-like substance 91 at the nozzle tip. One end of the hose 61 is connected to the outlet of the high-pressure mixer 5, and the other end is connected to the nozzle 7, whose tip is located in the cavity C. The length L7 of the nozzle 7 plus the length L61 of the hose are set so that the high-pressure mixed liquids A and B reach a cream state 91 with a specific gravity of less than 1 along the path (Figure 3). Here, the length of the nozzle 7 is appropriately selected within the range of 500 to 2,000 mm. For example, if the cavity depth is 1,000 mm or less, the length is set to {tunnel concrete thickness [mm] + cavity depth [mm] - 50 [mm]}, and the nozzle is inserted up to 50 mm before the natural ground. If the cavity depth is 1,000 mm or more, the length is set to {tunnel concrete thickness [mm] + 1,000 [mm]}, and the nozzle is filled to a depth of 1,000 mm and then refilled. The nozzle length L7 is then increased so that it reaches 50 mm before the natural ground. The hose length L61 is set to approximately 1,500 mm, and the nozzle diameter is approximately 20 mmφ, while the diameter of the hose 61 is set to a diameter equal to or larger than this. Thus, liquid A and liquid B are mixed under high pressure in the high-pressure mixer 5, and foaming raw material g, which is the reaction between the polyol component and the isocyanate component, becomes a reaction-progressing fluid, and by passing it through the hose 61 and the nozzle 7, the reaction time is increased, and it can be discharged from the tip opening of the nozzle 7 as a reaction-progressing fluid in the form of a cream-like substance 91 with a specific gravity of less than 1.

[0018] The air pipe 81 is an air supply tube connected to the hose 61 downstream of the high-pressure agitator 5 (FIG. 1). The air pipe 81 is provided to enable air to be injected from an air compressor (not shown) into the hose 61 downstream of the high-pressure agitator 5. Here, the low-pressure mixing in Patent Document 1 also mixes and mixes liquid A and liquid B to form rigid urethane foam 93, but this mixing and mixing relies on compressed air. The compressed air is not necessary for the reaction itself of rigid urethane foam 93, and is an unnecessary non-reactive gas. If a large amount of compressed air is used, there is a risk that large voids will form in the filler of rigid urethane foam 93 that fills cavity C. We also consider a high-pressure foaming machine of the collision turbulent mixing type for rigid urethane foam concentrate, whose essential components are a polyisocyanate component, a polyol, and a blowing agent, as disclosed in Japanese Patent Laid-Open Publication No. 56-108497. If the distance from the high-pressure foaming machine to the nozzle 7 is short, it is difficult to discharge a creamy mass 91 with a specific gravity of less than 1 from the nozzle tip 70, no matter how high the pressure is to discharge and achieve collision turbulent mixing. Conversely, if the distance from the high-pressure foaming machine to the nozzle 7 is long, it is difficult to discharge a creamy mass 91 from the nozzle tip 70. High-pressure foaming produces a high-speed fluid under high pressure, and if the distance to the nozzle 7 is long, the resistance of the reaction-progressing fluid (creamy mass 91) flowing over that distance is high, making it difficult to flow. Furthermore, the surface of the creamy mass 91 becomes rough, resulting in cell roughness.

[0019] In contrast, the present invention solves this problem by injecting a small amount of air compressed by an air compressor into the hose 61 downstream of the high-pressure agitator 5. The injected small amount of air enables the reaction proceeding fluid, in the form of a creamy substance 91, to be discharged from the nozzle tip 70, which is located a sufficient distance from the high-pressure agitator 5 to the nozzle 7. At the same time, the problem of cell roughness is also solved. Injecting air forms a boundary film of the air on the inner wall of the hose 61, reducing the flow resistance of the reaction proceeding fluid, or creamy substance 91, flowing through the hose 61. The boundary film formed by the air also eliminates cell roughness. The rate of air injection into the hose 61 is extremely small, approximately 13 liters per minute. The compressed air used for low-pressure mixing in Patent Document 1 is significantly less than the large amount of air used, as described in paragraph 0056 of the same document, "...to prepare a foamed polyurethane raw material liquid containing a large amount of air." There is no risk of large voids forming in the rigid foamed polyurethane 93 filling the cavity C. Supplying air to the point downstream of the high-pressure agitator 5 where the hose 61 connects not only prevents cell breakdown but also reduces resistance to the reaction-progressing fluid (foaming raw material g) flowing through the hose 61 and nozzle 7. Here, air is supplied via air piping 81 to the point where the hose 61 connects immediately after exiting the high-pressure agitator 5, reducing resistance to the flow of the reaction-progressing fluid throughout the hose 61. The hose length L61 and nozzle length L7 from the tip of the nozzle 7 ensure sufficient discharge of a creamy mass 91.

[0020] The pressure gauge 62 for the reaction proceeding fluid is an instrument that measures the pressure of the reaction proceeding fluid between the polyol component and the isocyanate component that flows through the hose 61 after the A liquid and the B liquid are mixed under high pressure in the high-pressure agitator 5. The pressure gauge 62 is attached to the downstream side of the high-pressure agitator 5, at the joint with the hose 61 immediately after the air pipe 81 is connected. In this embodiment, an air pressure gauge 83 is attached to the air pipe 81 that introduces air into the connection between the high-pressure agitator 5 and the hose 61. While this air pressure gauge 83 can be relied upon, the addition of the reaction fluid pressure gauge 62 allows for more direct and accurate measurement of the properties of the creamy mass 91 discharged from the nozzle tip 70. However, if the reaction fluid pressure gauge 62 were attached to the flow location of the reaction fluid resulting from the high-pressure mixing and reaction of liquids A and B in the high-pressure agitator 5, it would be necessary to wash and remove the foaming raw material g adhering to not only the hose 61 but also the reaction fluid pressure gauge 62 after injecting the required amount of creamy mass 91 into the cavity C from the nozzle tip 70, which would be troublesome. Nevertheless, in order to obtain more accurate information about the creamy mass 91 discharged from the nozzle tip 70 into the cavity C, a pressure gauge measuring the pressure of the reaction fluid flowing in the hose 61 is attached downstream of the high-pressure agitator 5 in the main flow of the reaction fluid. The injection pressure of the cream-like material 91 for rigid urethane foam to be filled into cavity C is directly detected by the pressure gauge 62 located downstream of the high-pressure mixer 5, where the reaction proceeding fluid flows, thereby providing the desired injection equipment that can more reliably and properly inject the cream-like material 91 for rigid urethane foam into cavity C. Reference numeral 73 denotes a connection joint, reference numeral 82 denotes an air on-off valve provided in the air pipe 81, and reference numeral GL denotes a road surface.

[0021] (2) Cavity repair method The cavity repair method is carried out using the injection equipment (1) as follows, for example. We will explain how to repair a cavity C behind the lining concrete R as shown in Figure 1, where there is a puddle W there. First, the entire injection equipment set is transported to the cavity repair site, and it is confirmed that the first pipe 21 from the first tank 1 and the second pipe 41 from the second tank 3 are both connected to the high-pressure mixer 5. Then, a hose 61 is connected between the high-pressure mixer 5 and a nozzle 7, the tip of which is located in the cavity C to be filled with the rigid urethane foam 93. In this example, the nozzle 7 is approximately 1,000 mm long, while the hose 61 is approximately 1,500 mm long, making the hose 61 longer. The hose 61 and nozzle 7 are set to lengths that allow the cream-like substance 91, with a specific gravity of less than 1, to be dispensed from the nozzle tip 70. Furthermore, the long hose 61 facilitates work by a worker aboard the deck D of the boom-type aerial work platform. The worker can then use a connection joint 73 to efficiently connect the tip of the hose 61 to the base end of the nozzle 7, which is already fixed to the lining concrete R. Near the workers on deck D, there are arranged a high-pressure agitator 5, thermometers 23 and 43, a pressure gauge 62 for the reaction proceeding fluid, and an air on-off valve 82. Around the same time, a generator (not shown) is started up, and the first and second heaters 26, 46 and the first and second hose heaters 22, 42 are adjusted according to the outside air temperature, so that liquid A and liquid B adjusted to predetermined temperatures can be sent from the first tank 1 and the second tank 3 through the first piping 21 and the second piping 41 to the high-pressure agitator 5. Also, the high-pressure pumps 25, 45 are started up, and the air compressor for supplying air to the air piping 81 is started up and put into standby mode.

[0022] Next, the worker on the aerial work vehicle pulls the lever 5a of the high-pressure agitator 5, and liquid A and liquid B are mixed under high pressure in the high-pressure agitator 5 to cause a reaction. Almost simultaneously with the operation of pulling the lever 5a, the air on-off valve 82 is opened to supply air to the downstream hose 61 of the high-pressure agitator 5. Liquid A and liquid B, which have been primarily heated in the first tank 1 and the second tank 3, are controlled to a predetermined temperature by the first and second heaters 26 and 46 and the first and second hose heaters 22 and 42 so that the urethane reaction proceeds smoothly, and are then sent to the high-pressure agitator 5 by the high-pressure pumps 25 and 45. These liquids A and B are sprayed from the fine holes 510 and 530 in the mixing and stirring section 5b. The foaming raw material g, which has been reacted by collision and mixing of the sprayed liquids A and B, becomes a reaction-promoting fluid and the reaction proceeds inside the hose 61 connected to the downstream side of the high-pressure agitator 5. The reaction proceeds while passing through the hose 61 and the nozzle 7, and a creamy substance 91 with a specific gravity of less than 1 is discharged from the tip opening 70 of the nozzle 7. The supply of air allows the reaction proceeding fluid to flow smoothly through the hose 61 and the nozzle 7, and further enables the discharge of a creamy substance 91 without cell roughness from the nozzle tip 70.

[0023] For a while, the operator checks with the thermometer that liquids A and B are being supplied to the high-pressure agitator 5 at the specified temperature, and also checks with the reaction proceeding fluid pressure gauge 62 that the creamy material 91 is being supplied in an appropriate state to the cavity C. While performing these checking operations, the operator continues to discharge the creamy material 91 from the nozzle tip opening 70 while keeping the lever 5a of the high-pressure agitator 5 pulled.

[0024] Even if a puddle W is present in the cavity C while the creamy substance 91 is being discharged, this cavity repair method does not cause any problems. As shown in Figure 1, the creamy material 91 discharged from the nozzle tip 70 moves downward due to gravity toward the puddle W in the cavity C. Then, even when it reaches the puddle W as shown in Figure 2, the creamy material 91 floats on the water surface W1 because its specific gravity is less than 1. The boundary surface 92 of the creamy material 91 contacts the water surface W1. However, unlike the case where the entire foaming raw material g, which has a specific gravity greater than 1 before becoming the creamy material 91, sinks in the water and foams abnormally, the abnormal portion of the creamy material 91 is limited to the boundary surface 92 with the water W. The abnormal portion remains a thin film.

[0025] Thereafter, the creamy material 91 continues to be discharged from the nozzle tip 70 until the cavity C is completely filled with the creamy material 91, as shown in Figure 3. An operator on deck D checks the progress of filling the cavity C with the creamy material 91 by checking the reading of the reaction proceeding fluid pressure gauge 62. Furthermore, a person on the ground communicates advance information to the worker on deck D, indicating that the amount of creamy material 91 being injected into cavity C is approaching the required amount, using flow meters 29, 49 installed on the ground facility side. The worker, while watching the information from flow meters 29, 49 and the pressure change on reaction proceeding fluid pressure gauge 62, confirms that the required amount of creamy material 91 has been injected into cavity C, and then returns lever 5a. Rod 57 advances, and the supply of liquids A and B to high-pressure mixer 5 stops. Thereafter, the reaction proceeding fluid remaining in the hose 61 is removed with air, and the air on-off valve 82 is closed to complete the repair work.

[0026] After that, from the state shown in Figure 3, for example, the cream-like material 91 that has filled the cavity C will, over time, push down the water surface W1 due to its foaming pressure, as shown in Figure 4. The puddle W will flow out of the cavity C through the gaps in the earthen wall S. After about a day has passed, the cream-like material 91 will have almost completely foamed and hardened, and the repair of the cavity C will be completed, with the entire cavity C filled with the desired hard foamed urethane 93, as shown in Figure 5. As described above, in response to the uncertainty of whether or not there is a puddle W in cavity C, this cavity collection method is a construction method that can take all possible measures, as shown in Figures 1 to 5, even if there is a puddle W. The other configurations are the same as those described in (1), so their explanation will be omitted. The same symbols as in (1) indicate the same or equivalent parts.

[0027] (3) Mixing performance comparison Table 1 shows the actual measurement values ​​of mixing performance at an outside temperature of 23°C, where (A) is a low-pressure foaming machine with a structure similar to that of Patent Document 1, and (B) is a high-pressure mixer 5, and the low-pressure foaming machine or the high-pressure mixer is connected to a nozzle 7 with a length of 1,000 mm and an inner diameter of 20 mmφ, the tip of which is placed in cavity C and attached to lining concrete R, by a hose with a length of 1,500 mm and an inner diameter of 19 mmφ. (C) is the result of investigating the device in (A) with a general-purpose static mixer further attached to the tip of the nozzle.

[0028] [Table 1]

[0029] In Table 1, the dimensional stability under wet heat was measured by measuring the amount of deformation after 24 hours at a temperature of 70°C and humidity of 95%, which corresponds to an accelerated test to observe changes after, for example, 10 years. In the table, the horizontal and vertical percentages refer to the egg-shaped rigid urethane foam 93 discharged from the tip opening 70 of the nozzle 7 or the static mixer and cured, so the lengthwise direction of the egg shape is taken as the vertical direction and the widthwise direction as the horizontal direction. As can be seen from Table 1, the high-pressure mixer 5 exhibits superior values ​​in almost all categories compared to the low-pressure foaming machine. Therefore, we investigated the degree of improvement by attaching a static mixer to the low-pressure foaming machine, but the high-pressure mixer 5 still showed superior results, particularly in terms of dimensional stability under moist heat. It can be seen that the rigid urethane foam 93 produced with the high-pressure mixer 5 exhibits almost no shrinkage over the long term, making it ideal for filling cavity C.

[0030] (4) Effects Unlike the low-pressure mixing of 0.1 to 0.2 MPa as in Patent Document 1, the cavity repair method and cavity repair injection equipment configured in this manner uses a high-pressure agitator 5 of 7 to 9 MPa to increase the degree of agitation and mixing of liquid A and liquid B, thereby accelerating the reaction and promoting a more homogenous urethane reaction. However, if a high-pressure agitator 5 is used and connected to a nozzle 7 with its tip located in the cavity C via a hose 6, the high pressure increases the resistance to the reaction-promoting fluid (foaming raw material g) passing through the hose 61 and nozzle 7. The present invention solves this problem of increased resistance by injecting air into the hose 61 downstream of the high-pressure agitator 5. Injecting air allows the air to penetrate between the reaction-promoting fluid and the tube walls of the hose 61 and nozzle 7, acting like a lubricant, preventing the reaction-promoting fluid from rubbing against the tube walls as it progresses. Furthermore, even a small amount of air is effective, and does not require as much air as is required for mixing in low-pressure foaming.

[0031] The length of the nozzle 7 and the length of the hose 61 are set so as to allow the reaction time to progress and produce a creamy substance 91 having a specific gravity of less than 1, which is then discharged from the tip opening of the nozzle 7 as the creamy substance 91.

[0032] However, if a high-pressure agitator 5 is used and the lengths of the nozzle 7 and the hose 61 are set so that the reaction proceeding fluid becomes a cream-like mass 91 with a specific gravity of less than 1, the resistance to fluid flow within the hose 61 and the nozzle 7 becomes too great, and there is a concern that the cream-like mass 91 discharged from the nozzle tip opening 70 may suffer from cell roughness. This problem can be solved by connecting an air pipe 81 to the hose 61 downstream of the high-pressure agitator 5 and injecting a small amount of air into the hose 61 downstream of the high-pressure agitator 5. Injecting a small amount of air is thought to form an air film on the inner wall of the hose, reducing the resistance to liquid flow within the hose 61 and nozzle 7 even if the hose 61 and nozzle 7 are long. This air film then prevents cell breakdown. Therefore, using the high-pressure agitator 5 makes it possible to increase the mixing efficiency of liquid A and liquid B. The longer the passage time through the hose 61 and nozzle 7, the more the reaction progresses, allowing a cream-like substance 91 with a specific gravity of less than 1 and no cell breakdown to be discharged from the nozzle tip 70.

[0033] First, by making the high-pressure agitator 5 an essential component, mixing efficiency is increased, contributing to the formation of rigid urethane foam 93 of consistent quality, and second, by adopting a configuration including air piping 81 for injecting air into hose 61, a high-pressure agitator 5 with high liquid resistance can be used, and hose 61 can be interposed between the high-pressure agitator 5 and nozzle 7 rather than directly connecting them. The interposition of hose 61 improves usability. Thirdly, the length of the nozzle 7 and the hose 61 promotes the reaction within the hose 61 and the nozzle 7, making it possible to discharge a creamy substance 91 with a specific gravity of less than 1 from the nozzle tip opening 70.

[0034] By configuring the present invention as described above, a cream-like substance 91 with a specific gravity of less than 1 and free of cell roughness can be discharged from the nozzle tip opening 70, and when the urethane raw material is injected into the cavity C, there is no problem even if water accumulates in the cavity C. The specific gravity of the urethane raw material is 1.21, which is heavier than water. If the A and B liquids in the foaming raw material g injected into cavity C are not mixed or stirred properly, or if the reaction time between A and B liquids is insufficient, a reaction-progressing fluid containing unreacted material will be discharged from the nozzle tip 70. If there is a puddle W in cavity C, the unreacted material will sink in the water and foam, and then float up when the specific gravity becomes less than 1. At this time, the area in contact with water is large, and the amount of abnormal foaming increases proportionally.

[0035] In contrast, the present invention solves this problem by discharging a cream-like material 91 with a specific gravity of less than 1 from the nozzle tip opening 70 as described above, and preventing the material from sinking into a puddle W even if the puddle W exists in the cavity C. In other words, with the above-described configuration of the present invention, in which a cream-like material 91 with a specific gravity of less than 1 is discharged from the nozzle tip opening 70, even if there is a puddle W in the cavity C at the site, the material will sit on the water surface W1 (FIGS. 2 and 3), and contact of the cream-like material 91 with the water surface will be minimized to the boundary surface 92. The abnormal foam layer at the boundary surface 92 can be limited to about 2 mm. As the cream-like material 91 is further injected into cavity C, its pressure pushes down the water surface W1, causing the water in puddle W to flow out into the soil (Figure 4). After that, when the cream-like material 91 reaches the stage of foaming and hardening into rigid urethane foam 93, the abnormally foamed layer formed at interface 92 is also crushed, and cavity C is filled with the desired high-quality rigid urethane foam 93. Note that even if there are no gaps in the soil and the water in puddle W cannot flow out, the formation of rigid urethane foam 93 is completed and the abnormally thin layer remains at interface 92, so there is no problem.

[0036] If a pressure gauge 62 for measuring the pressure of the reaction-promoting fluid is installed downstream of the high-pressure agitator 5, the pressure of the reaction-promoting fluid itself near the nozzle tip 70 can be determined. This makes it possible to more accurately determine whether the reaction-promoting fluid being discharged from the nozzle tip 70 has become a creamy mass 91. Unlike Patent Document 1, which uses a pressure sensor attached to the air inlet pipe for compressed air for mixing and agitation, this method provides more direct information about the reaction-promoting fluid being discharged from the nozzle tip 70, which contributes to filling the cavity C with high-quality rigid urethane foam 93.

[0037] Furthermore, by providing a first heater 26 that heats the polyol component compound liquid passing through the first pipe 21 and a second heater 46 that heats the isocyanate component compound liquid passing through the second pipe 41, the cavity C can be filled with high-quality rigid urethane foam 93 regardless of seasonal variations. The reaction rate between liquid A and liquid B is affected by temperature. In cold winter months, the reaction between liquid A and liquid B slows down, and there is a risk that unreacted material will be injected into cavity C from the nozzle tip opening 70. However, in the present invention, the polyol component compounded liquid passing through the first pipe 21 is heated by the first heater 26 and the isocyanate component compounded liquid passing through the second pipe 41 is heated by the second heater 46 according to the outside air temperature, and the temperatures are adjusted and controlled to predetermined levels, allowing liquid A and liquid B to react in the high-pressure agitator 5 under appropriate temperature conditions, so that cavity C can be filled with rigid urethane foam 93 of consistent quality all year round.

[0038] Furthermore, in Patent Document 1, shut-off ball valves are attached to both liquid A and liquid B, and if they are not closed simultaneously after work is completed, there is a possibility that unreacted urethane will remain. On the other hand, in the present invention, liquid A and liquid B are opened and closed approximately simultaneously by the forward and backward movement of rod 57 as shown in Figures 6 and 7, so there is no chance that only one liquid will be ejected from nozzle tip 70. Cavity C can be filled with rigid urethane foam 93 of stable quality. As described above, the cavity repair method and cavity repair injection equipment of the present invention exhibit the various excellent effects described above and are extremely useful.

[0039] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention depending on the purpose and application. The shape, size, number, materials, etc. of the first tank 1, first piping 21, first heater 26, second tank 3, second piping 41, second heater 46, high-pressure agitator 5, hose 61, nozzle 7, tip port, air piping 81, cavity C, etc. can be selected appropriately depending on the application. Although the embodiment describes a cavity formed behind the lining concrete of a tunnel, the cavity is not limited to this, and cavities formed in the ground of a building are also within the scope of application of the present invention. [Explanation of symbols]

[0040] 1. First tank for polyol component 1a Polyol component blend liquid (liquid A) 21 First Piping 22 First hose heater 26 First heater 3 Second tank for isocyanate component 3a Isocyanate component compound liquid (liquid B) 41 Second piping 42 Second hose heater 46 Second heater 5. High-pressure mixer 61 Hose 62 Pressure gauge for reaction fluid (pressure gauge) 7 nozzles 70 Tip (nozzle tip) 81 Air piping 91 Creamy substance (Creamy substance with specific gravity less than 1) 93 Hard urethane foam C cavity

Claims

1. The system comprises a high-pressure agitator, one end of which is connected to a first tank for a polyol component and the other end of which is connected to a second tank for an isocyanate component, a hose connecting the high-pressure agitator to a nozzle whose tip is disposed in a cavity into which the rigid urethane foam is to be filled, and an air pipe connected to the hose downstream of the high-pressure agitator, The injection equipment for cavity repair is characterized in that a polyol component compounded liquid and an isocyanate component compounded liquid are mixed under high pressure in the high-pressure mixer, the polyol component and the isocyanate component react with each other, and the foaming raw material in which the reaction progresses is discharged from the nozzle, causing the foaming and hardening into the rigid foamed urethane.

2. The system comprises a high-pressure agitator, one end of which is connected to a first tank for a polyol component and the other end of which is connected to a second tank for an isocyanate component, a hose connecting the high-pressure agitator to a nozzle whose tip is disposed in a cavity into which the rigid urethane foam is to be filled, and an air pipe connected to the hose downstream of the high-pressure agitator, The injection equipment for cavity repair is characterized in that the combined length of the hose and the nozzle is set so that a polyol component compound liquid and an isocyanate component compound liquid are mixed under high pressure in the high-pressure mixer, the polyol component and the isocyanate component react with each other, and the resulting mixture is discharged from the tip of the nozzle as a cream-like substance having a specific gravity of less than 1.

3. A cavity repair method using an injection equipment for cavity repair described in claim 1 or 2.

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