Foaming agent addition apparatus, spray foaming machine, foaming agent addition method, and foam manufacturing method

Abstract

The present invention provides a foaming agent addition apparatus, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can stably supply a foaming agent to a liquid flowing through a liquid channel without being affected by the pulsation of a liquid pump. [Solution] A foaming agent addition device for liquid L1 supplied by a liquid pump 40, comprising: a liquid flow path pressure gauge 31; a liquid pump drive detection unit 41; a foaming agent container 11; a foaming agent flow path 12 for flowing foaming agent E; a foaming agent pressure gauge 81 for the foaming agent flow path 12; a foaming agent pressurizing pump 80 for foaming agent E; a foaming agent metering pump 50; an on-off valve 60 for controlling the addition of foaming agent E to liquid L1 by opening and closing; and a control unit 61 for controlling the opening of the on-off valve 60 according to the drive status of the liquid pump 40 detected by the pump drive detection unit 41.

Description

Technical Field

[0003]

[0001] The present invention relates to a foaming agent adding device for adding a foaming agent to a liquid, a spraying foaming machine, a foaming agent adding method, and a foam manufacturing method.

Background Art

[0002] Conventionally, a construction method for forming polyurethane foam by mixing polyol and isocyanate on-site and spraying and foaming the mixture onto the roof, wall surface, floor, etc. of buildings and structures is widely known. As a method for assisting the workability of polyurethane foam, for example, when mixing two components of polyol and isocyanate, a method of adding a foaming agent as a third component (hereinafter referred to as the "froth method") is widely known. In the froth method, for example, a foaming agent flow path is provided that is connected to a liquid flow path for supplying polyol or isocyanate, and carbon dioxide or the like as a foaming agent is added to the polyol or isocyanate in the liquid flow path from a tank or the like through the foaming agent flow path. A generally used foaming agent adding device is used. The polyol or isocyanate to which a foaming agent such as carbon dioxide is added in the foaming agent adding device is further mixed with isocyanate or polyol and then discharged outward.

[0003] Generally, the liquid in the liquid flow path of the foaming agent adding device is supplied in a pressurized state, and the foaming agent is pressurized to a pressure higher than the liquid pressure in the liquid flow path and then added to the liquid flow path, so that it can be stably mixed with the liquid. Therefore, a device is used that measures the liquid pressure in the liquid flow path and the foaming agent pressure in the foaming agent flow path, and controls the opening of an on-off valve to add the foaming agent to the liquid when the foaming agent pressure is higher than the liquid pressure (see, for example, Patent Document 1). In addition, a device is also disclosed that controls the addition of the foaming agent to the liquid by pressurizing the foaming agent pressure to a pressure higher than the liquid pressure in the liquid flow path without using a foaming agent pump by heating the foaming agent container, and adding the foaming agent to the liquid by the differential pressure between the foaming agent pressure and the liquid pressure (see, for example, Patent Documents 2 to 3).

Prior Art Documents

[0004] [Patent Document 1] Patent No. 6395556 [Patent Document 2] Patent No. 5255239 [Patent Document 3] Patent No. 5255380 [Overview of the project] [Problems that the invention aims to solve]

[0005] In conventional foaming agent additive systems, the foaming agent pressure must be higher than the liquid pressure to be added. Therefore, the addition of the foaming agent is controlled by detecting the liquid pressure in the liquid channel. However, in conventional foaming agent additive systems, the liquid flowing through the liquid channel is supplied by a liquid pump in a pulsating manner. As a result, the liquid pressure in the liquid channel is easily affected by the pulsation of the liquid pump, making it difficult to control the addition of the foaming agent using a control method that responds to liquid pressure. Furthermore, the amount of foaming agent added fluctuates depending on the pressure difference between the liquid pressure and the foaming agent pressure when the valve is opened and the foaming agent is added to the liquid, as well as the opening time of the valve. This makes it difficult to quantitatively determine the amount of foaming agent added and thus difficult to adjust the amount of foaming agent added. Furthermore, in foaming agent additive devices, it has been considered to provide a foaming agent pressurizing pump to pressurize the foaming agent in the foaming agent channel in order to stabilize the pressure within the foaming agent channel. However, when the pressure of the foaming agent in the foaming agent channel is increased by the foaming agent pressurizing pump, the load on the pump increases, making it difficult to maintain the pressure of the foaming agent and thus difficult to adjust the amount of foaming agent added. Furthermore, in foaming agent additive devices, from the perspective of preventing backflow from the liquid channel to the foaming agent channel, it has been considered to install a foaming agent pressurizing pump to maintain the foaming agent pressure at a higher pressure than the liquid pressure. However, when pressurizing the foaming agent pressure with a foaming agent pressurizing pump in order to maintain a high foaming agent pressure, it is necessary to increase the pressure of the foaming agent in the foaming agent container in order to reduce the pressure difference between the foaming agent pressure in the container and the foaming agent pressure increased by the foaming agent pressurizing pump. If the pressure inside the foaming agent container is increased by, for example, heating the foaming agent container, it increases the equipment costs for heating the foaming agent container and carries the risk of over-pressurizing the foaming agent container. Maintaining a high foaming agent pressure solely by pressurizing with a foaming agent pressurizing pump without increasing the pressure inside the foaming agent container results in a large pressure difference between the pressure inside the foaming agent container and the pressure increased by the foaming agent pressurizing pump, which slows down the increase in foaming agent pressure and makes it difficult to adjust the amount of foaming agent added. Furthermore, carbon dioxide is often used as the blowing agent to be added, from the perspective of cost reduction. Carbon dioxide as an additive is easily vaporized, and especially at high temperatures such as in summer, the pressure of carbon dioxide in the blowing agent container tends to become higher than usual. In conventional blowing agent addition devices, the flow path is connected from the blowing agent container to the on / off valve that controls the amount of blowing agent added to the liquid. As a result, when the pressure of the blowing agent in the blowing agent container becomes high, the pressure difference between the blowing agent and the liquid in the liquid flow path becomes large, making it easy to add too much blowing agent and making it difficult to adjust the amount of blowing agent added.

[0006] Therefore, the present invention aims to provide a foaming agent addition device, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can stably supply a foaming agent to a liquid flowing through a liquid channel without being affected by the pulsation of the liquid pump, by using control that corresponds to the drive of the liquid pump rather than control that corresponds to the liquid pressure in the liquid channel. Furthermore, the present invention aims to provide a foaming agent addition device, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can supply a predetermined amount (predetermined volume) of foaming agent to a liquid flowing through a liquid channel by utilizing a foaming agent metering pump that supplies a predetermined amount of foaming agent to a liquid flowing through a liquid channel. Furthermore, the present invention aims to provide a foaming agent addition device, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that, when using a foaming agent pressure pump, can reduce the burden on the foaming agent pressure pump, maintain the function of the foaming agent pressure pump, and stably supply the foaming agent. Furthermore, the present invention aims to provide a foaming agent addition device, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can prevent the addition of an excess of foaming agent to a liquid by providing a flow rate adjustment mechanism in the flow path from the foaming agent container to an on-off valve that controls the amount of foaming agent added to the liquid. [Means for solving the problem]

[0007] The present invention is summarized in the following [1] to

[15] . [1] A foaming agent addition device for adding a foaming agent to a liquid supplied by a liquid pump and flowing through a liquid channel, comprising: a liquid channel pressure gauge for measuring the pressure of the liquid flowing through the liquid channel; a pump drive detection unit for detecting the operation of the liquid pump; a foaming agent container for containing the foaming agent; a foaming agent channel for flowing the foaming agent supplied from the foaming agent container; a foaming agent pressure gauge for measuring the pressure of the foaming agent flowing through the foaming agent channel; a foaming agent pressurizing pump for pressurizing the foaming agent flowing through the foaming agent channel so that the pressure of the foaming agent measured by the foaming agent pressure gauge is lower than the liquid pressure measured by the liquid channel pressure gauge; a foaming agent metering pump for supplying a predetermined amount of the foaming agent to the liquid channel; an on-off valve for controlling the addition of the foaming agent to the liquid by opening and closing it; and a control unit for controlling the opening of the on-off valve according to the operation status of the liquid pump detected by the pump drive detection unit. [2] The foaming agent adding apparatus according to [1], wherein the control unit opens the on-off valve when the driving position of the liquid pump reaches a predetermined position. [3] The foaming agent adding device according to [1] or [2], wherein the control unit controls the closing of the on / off valve when a predetermined amount of the foaming agent is added to the liquid. [4] The blowing agent metering pump is a positive displacement pump, as described in any of [1] to [3]. [5] The foaming agent metering pump is a reciprocating pump, as described in any of [1] to [4]. [6] The foaming agent pressurizing pump is a pump that continuously pressurizes the foaming agent, the foaming agent adding apparatus according to any one of [1] to [5]. [7] The foaming agent pressurizing pump is either an axial pump or a gear pump, as described in any of [1] to [6]. [8] The foaming agent adding apparatus according to any one of [1] to [7], wherein the liquid comprises a polyol or a polyisocyanate. [9] The foaming agent adding apparatus according to any one of [1] to [8], wherein the liquid contains a filler.

[10] The blowing agent comprising carbon dioxide, a blowing agent adding apparatus according to any one of [1] to [9].

[11] The blowing agent adding apparatus according to any one of [1] to

[10] , wherein the control unit controls the on / off valve not to open when the liquid pressure measured by the liquid flow pressure gauge is lower than a predetermined value.

[12] A foaming agent adding device according to any one of [1] to

[11] , further comprising a flow rate adjustment mechanism for adjusting the flow rate of the foaming agent in the foaming agent flow path upstream of the on / off valve.

[13] The foaming agent addition apparatus according to

[12] , wherein the flow rate adjustment mechanism is a second on-off valve that controls the flow rate of the foaming agent flowing in the foaming agent channel upstream of the on-off valve by opening and closing it. A spray foaming machine equipped with a foaming agent addition device as described in any of

[14] [1] to

[13] .

[15] A method for adding a foaming agent to a liquid supplied by a liquid pump and flowing through a liquid channel, comprising the steps of: supplying a foaming agent contained in a foaming agent container to a foaming agent channel; measuring the pressure of the foaming agent flowing through the foaming agent channel with a foaming agent pressure gauge; measuring the pressure of the liquid flowing through the liquid channel with a liquid channel pressure gauge; and flowing the foaming agent channel such that the pressure of the foaming agent measured by the foaming agent pressure gauge is lower than the pressure of the liquid measured by the liquid channel pressure gauge. A method for adding a foaming agent, comprising the steps of: pressurizing the foaming agent with a foaming agent pressure pump; detecting the operation of the liquid pump with a pump drive detection unit; measuring a predetermined amount of the foaming agent to be supplied to the liquid flow path with a foaming agent metering pump; and controlling the addition of the foaming agent to the liquid by opening and closing an on-off valve, wherein in the step of controlling the addition of the foaming agent by opening and closing an on-off valve, the control unit controls the opening of the on-off valve according to the operation status of the liquid pump detected by the liquid pump drive detection unit.

[16] The method for adding a foaming agent according to

[15] , wherein in the step of controlling the addition of the foaming agent by opening and closing an on-off valve, the on-off valve is controlled not to open when the measured pressure of the liquid pressure gauge is lower than a predetermined value. A method for producing a foam, comprising the step of adding a foaming agent to a liquid flowing through a liquid channel by the foaming agent addition method described in

[17] ,

[15] , or

[16] . [Effects of the Invention]

[0008] In the present invention, instead of controlling the liquid flow path according to the liquid pressure, the control is based on the driving status of the liquid pump. This allows for the stable supply of a foaming agent to the liquid flowing through the liquid flow path without being affected by the pulsation of the liquid pump. This provides a foaming agent addition device, a foaming machine for spraying, a foaming agent addition method, and a foam manufacturing method. Furthermore, the present invention provides a foaming agent addition device, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can supply a predetermined amount (predetermined volume) of foaming agent to a liquid flowing through a liquid channel by utilizing a foaming agent metering pump that supplies a predetermined amount of foaming agent to a liquid flowing through a liquid channel. In addition, when using a foaming agent pressurizing pump, the present invention can provide a foaming agent addition device, a spraying foaming machine, a foaming agent addition method, and a foam manufacturing method that can reduce the burden on the foaming agent pressurizing pump, maintain the function of the foaming agent pressurizing pump, and stably supply the foaming agent.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic diagram showing a foaming agent addition device according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram showing a spraying foaming machine according to a first embodiment of the present invention. [Figure 3] It is a flowchart showing a foaming agent addition method according to a first embodiment of the present invention. [Figure 4] It is a schematic diagram (Part 1) showing a foaming agent addition device according to a second embodiment of the present invention. [Figure 5] It is a schematic diagram (Part 2) showing a foaming agent addition device according to a second embodiment of the present invention. [Figure 6] It is a flowchart (Part 1) showing a foaming agent addition method according to a second embodiment of the present invention. [Figure 7] It is a flowchart (Part 2) showing a foaming agent addition method according to a second embodiment of the present invention. [Figure 8] It is a schematic diagram showing a foaming agent addition device according to other embodiments of the present invention.

Modes for Carrying Out the Invention

[0010] [First Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the foaming agent addition device 10 according to the first embodiment is a device for mixing the foaming agent E into the liquid L1 flowing through the liquid flow path 30.

[0011] <Liquid> Liquid L1 is not particularly limited, but foam raw material, which is a raw material for foam, is preferred. The foaming agent addition device 10 can produce foam by mixing foaming agent E with liquid L1, which is a foam raw material. Examples of foams include polyurethane foam, phenolic foam, and polystyrene foam. Therefore, liquid L1 can be anything that can be used as a raw material for these foams. Among the foams mentioned above, polyurethane foam is preferred from the viewpoint of ease of manufacture, curing speed, and foamability. Furthermore, rigid polyurethane foam is even more preferred. Using rigid polyurethane foam tends to result in good self-adhesion, heat insulation, and mechanical strength.

[0012] A polyurethane resin composition for forming polyurethane foam is generally prepared by mixing a liquid containing a polyol and a liquid containing a polyisocyanate. The polyurethane resin composition is foamed and cured by a foaming agent E mixed into the composition to form polyurethane foam. The foaming agent E can be mixed into either the liquid or the liquid, but it is preferable to mix it into the liquid from the viewpoint of stability and other factors. That is, the foaming agent adding device 10 preferably mixes the liquid foaming agent E into a liquid (liquid or liquid) containing either a polyol or a polyisocyanate, but it is more preferable to mix the foaming agent E into a liquid (liquid) containing a polyol. The liquid containing the polyol (liquid 1) is preferably a polyol composition containing a catalyst and a foam stabilizer in addition to the polyol, and may further contain a blowing agent. The blowing agent thus pre-contained in liquid 1 (polyol composition) is also called an "internally added blowing agent" to distinguish it from the blowing agent E described above.

[0013] Furthermore, the urethane resin composition for forming the polyurethane foam may contain a filler. The inclusion of a filler in the urethane resin composition improves the flame retardancy of the resulting polyurethane foam. It is preferable to mix the filler with a liquid (one or two liquids) containing either a polyol or a polyisocyanate, but it is more preferable to mix the filler with a liquid (one liquid) containing a polyol. Fillers are components that are present as solids in liquid raw material compositions, and generally exist as granular or powdery components in raw material compositions. The filler can be any component that is solid at room temperature (23°C) and atmospheric pressure (1 atm) and does not dissolve in a liquid raw material composition. Examples of fillers include solid flame retardants and settling inhibitors. Examples of solid flame retardants include red phosphorus-based flame retardants, boron-containing flame retardants, bromine-containing flame retardants, phosphate-containing flame retardants, chlorine-containing flame retardants, antimony-containing flame retardants, metal hydroxides, and needle-shaped fillers, and it is preferable that at least one is selected from the group consisting of red phosphorus-based flame retardants, boron-containing flame retardants, and bromine-containing flame retardants.

[0014] Furthermore, in addition to curing catalysts, foam stabilizers, and fillers, polyol compositions may also contain various additives such as flame retardants (solid flame retardants, liquid flame retardants), antioxidants, heat stabilizers, metal damage inhibitors, antistatic agents, crosslinking agents, lubricants, softeners, and pigments.

[0015] <Foaming agent> While not particularly limited, hydrofluoroolefins (HFOs), hydrofluorocarbons (HFCs), hydrocarbons, and diethyl ethers can be used as internally added blowing agents. Examples of hydrofluoroolefins (HFOs) used as internally added blowing agents include fluoroalkenes with approximately 3 to 6 carbon atoms, preferably with 3 or 4 carbon atoms, and more preferably with 3 carbon atoms. Hydrofluoroolefins may also be hydrochlorofluoroolefins having chlorine atoms. Examples of hydrofluorocarbons (HFCs) include hydrofluorocarbons with approximately 1 to 4 carbon atoms, and hydrofluorocarbons may also have chlorine atoms. Examples of hydrocarbons include hydrocarbons with 2 to 5 carbon atoms. Of the hydrocarbons with 2 to 5 carbon atoms, hydrocarbons with 3 or 4 carbon atoms are preferred, and LPG mainly composed of propane and butanes can also be used.

[0016] On the other hand, the blowing agent E can be any blowing agent that can be used for foaming by the Floss method, and can be any blowing agent that becomes a gas at room temperature (23°C) and atmospheric pressure (1 atm), preferably one whose boiling point is less than 0°C at atmospheric pressure. The blowing agent E is not particularly limited, but examples include hydrofluoroolefin (HFO) and carbon dioxide. The Floss method involves mixing the blowing agent E, which becomes a gas at room temperature and atmospheric pressure, with a foam raw material such as a liquid containing a polyol (1 liquid) to cause foaming. The liquid containing a polyol may already contain a blowing agent (internal blowing agent), in which case the blowing agent E functions as a foaming aid to improve foaming properties and workability.

[0017] In the present invention, carbon dioxide is preferably used as the foaming agent E. Carbon dioxide can be mixed with liquid L1 in a liquid state by pressurizing as described later, thereby improving its miscibility with liquid L1. Furthermore, using carbon dioxide reduces the environmental impact. However, carbon dioxide may also be mixed with liquid L1 in a supercritical or subcritical state. When using carbon dioxide as the blowing agent E, it may be used alone, or a mixed gas of hydrofluoroolefin (HFO) and carbon dioxide may be used.

[0018] (Foaming agent addition device) The foaming agent addition device 10 will be described in more detail below. The foaming agent addition device 10 comprises a liquid flow path pressure gauge 31, a pump drive detection unit 41, a foaming agent container 11, a foaming agent flow path 12, a foaming agent pressure gauge 81, a foaming agent pressurizing pump 80, a foaming agent metering pump 50, an on / off valve 60, and a control unit 61. The foaming agent addition device 10 is a device for adding a foaming agent E to a liquid L flowing through a liquid flow path 30.

[0019] A liquid pump 40 is connected to the liquid channel 30, and liquid L1, which is filled in a container such as a drum (not shown), is supplied to the liquid channel 30 by the liquid pump 40 and discharged. The liquid pump 40 may be either a positive displacement pump or a non-positive displacement pump, but a positive displacement pump is preferred. Although positive displacement pumps have large pulsations, according to the present invention, stable supply of the foaming agent is possible even with large pulsations. The positive displacement pump may be either a reciprocating pump or a rotary pump, but a reciprocating pump such as a syringe pump with the seal mechanism on the drive unit side and a plunger pump with the seal mechanism on the cylinder side is preferred. Furthermore, the positive displacement pump may be a variable displacement pump or a constant displacement pump. The liquid pump 40 repeatedly discharges fluid by periodically driving various drive parts such as cylinders, gears, vanes, and plungers by rotation or linear motion, depending on the type of pump. For example, in a syringe pump, the cylinder repeatedly moves linearly between the bottom dead center and the top dead center.

[0020] The liquid L1 flowing through the liquid channel 30 is flowed under pressurized discharge pressure. A liquid channel pressure gauge 31 is connected to the liquid channel 30, and the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 is measured by the liquid channel pressure gauge 31. From the viewpoint of operational stability, the pressure LP of the liquid L1 flowing through the liquid channel 30 is preferably 5 to 10 MPa. The liquid channel pressure gauge 31 transmits the measured liquid pressure LP to the control unit 61.

[0021] The liquid pump 40 is equipped with a pump drive detection unit 41. The pump drive detection unit 41 detects the operation of the liquid pump 40. The pump drive detection unit 41 transmits pump drive information DI related to the detected operation of the liquid pump 40 to the control unit 61. As described above, the liquid pump 40 periodically drives the drive unit by reciprocating or rotational motion, and the pump drive detection unit 41 can detect the position in which the drive unit is driven during that period. For example, in a reciprocating pump such as a syringe pump, the pump moves back and forth between the bottom dead center and the top dead center, and the pump drive detection unit 41 can detect the position in which the pump's drive unit is driven during that reciprocating motion. Similarly, in a rotary pump, it is sufficient to detect the position in which the drive unit is driven during the rotational motion. A sensor is used as the pump drive detection unit 41. Specific examples of sensors include a laser distance sensor that measures the drive position of the liquid pump 40 as a distance, and a position sensor that detects when the liquid pump 40's drive unit reaches a certain position (for example, top dead center or bottom dead center).

[0022] A pressure-resistant container can be used as the foaming agent container 11, for example, a known gas cylinder can be used. The foaming agent container 11 is preferably used to store the foaming agent E under pressure. The foaming agent container 11 may also be equipped with a heater (not shown), and by heating with the heater, the internal pressure of the foaming agent container 11 will increase, thereby reducing the burden on the foaming agent pressurizing pump 80 to pressurize, and making it easier to send the foaming agent E to the foam flow path 12 under high pressure.

[0023] As described above, the foaming agent channel 12 is a path for supplying the foaming agent E from the foaming agent container 11 to the liquid channel 30. The foaming agent channel 12 may be equipped with a channel cooling device (not shown) consisting of a coolant or the like, which can cool the foaming agent E flowing through the foaming agent channel 12. Cooling the foaming agent E in the foaming agent channel 12 makes it less likely for the foaming agent E to vaporize in each foaming agent channel, making it easier to mix with the liquid L in a liquid state. It is preferable to maintain the temperature inside the foaming agent channel 12 in the range of -20 to 20°C.

[0024] A foaming agent pressure gauge 81 is provided in the foaming agent flow path 12. The foaming agent pressure gauge 81 measures the foaming agent pressure EP of the foaming agent E flowing through the foaming agent flow path 12. The foaming agent flow path pressure gauge 81 transmits the measured foaming agent pressure EP to the control unit 61.

[0025] A foaming agent pressure pump 80 is provided in the foaming agent flow path 12. The foaming agent pressure pump 80 is connected to the control unit 61 and is located upstream of the foaming agent metering pump 50 in the foaming agent flow path 12. The foaming agent pressure pump 80 reduces the load on the foaming agent pressure pump and makes it easier to maintain the function of the foaming agent pressure pump by pressurizing the foaming agent E flowing through the foaming agent flow path 12 so that its foaming agent pressure EP is lower than the pressure LP of the liquid L1 flowing through the liquid flow path 30. From the viewpoint of preventing excessive addition of the foaming agent E to the liquid channel 30, the foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 is preferably 0.1 to 3 MPa or more lower than the pressure LP of the liquid L1 flowing through the liquid channel 30. The foaming agent pressurizing pump 80 is preferably a pump that can pressurize and supply the foaming agent E at a stable pressure, from the viewpoint of enabling the supply of a constant amount of foaming agent E to the foaming agent metering pump 50, and more preferably a pump that continuously pressurizes the foaming agent, and among these, either an axial pump or a gear pump is preferred. The foaming agent pressure EP inside the foaming agent channel 12 is prone to changes, such as a decrease due to suction from the foaming agent metering pump 50. These changes in foaming agent pressure EP can cause problems such as vaporization or backflow of the foaming agent E. Therefore, it is preferable to adjust the foaming agent pressure EP of the foaming agent E sent to the liquid channel 30 and the foaming agent metering pump 50 to be in the range of 5 to 12 MPa. By adjusting the foaming agent E in the foaming agent channel 12 to within the above range, it becomes easier to supply it to the liquid channel 30 in a liquid state. When the foaming agent E is supplied to the liquid channel 30 in a liquid state, it becomes easier to mix with the liquid L1.

[0026] The foaming agent pressurizing pump 80 is preferably controlled by the control unit 61. The control unit 61 compares the liquid pressure LP received from the liquid flow path pressure gauge 31 with the foaming agent pressure EP received from the foaming agent pressure gauge 81, and controls the foaming agent pressurizing pump 80 to pressurize the foaming agent E flowing through the foaming agent flow path 12 so that the foaming agent pressure EP is lower than the pressure LP of the liquid L1 flowing through the liquid flow path 30. The control unit 61 also controls the supply of foaming agent E from the foaming agent pressurizing pump 80 to the foaming agent metering pump 50 to continue when the foaming agent pressure EP is below a predetermined pressure. Furthermore, the control unit 61 may control the supply of foaming agent E from the foaming agent pressurizing pump 80 to the foaming agent metering pump 50 to stop when the foaming agent pressure EP reaches a predetermined pressure. As described above, by controlling the foaming agent pressure EP of the foaming agent E, it is possible to stably supply the foaming agent E to the foaming agent metering pump 50 located downstream.

[0027] A foaming agent metering pump 50 is provided in the foaming agent channel 12. The foaming agent metering pump 50 receives and meters the foaming agent E flowing through the foaming agent channel 12, thereby supplying a predetermined amount (predetermined volume) of foaming agent E to the liquid channel 30. By providing the foaming agent metering pump 50, even if the foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 is lower than the liquid pressure LP, the foaming agent E supplied to the liquid channel 30 can be made to a pressure higher than or equal to that of the liquid L1 flowing through the liquid channel 30, thereby preventing backflow of the liquid L1. The foaming agent metering pump 50 may be non-positive displacement or positive displacement, but a positive displacement pump is preferred because it is easy to supply a constant amount of foaming agent and the volume can be easily varied. As a positive displacement pump, reciprocating pumps such as syringe pumps and plunger pumps are preferred, and among these, syringe pumps are preferred because they have high metering accuracy for single-shot amounts and are also excellent for high-pressure transport. Furthermore, by using a positive displacement pump, especially a syringe pump, even if the foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 is lower than the liquid pressure LP, it is easy to pressurize the foaming agent E with the foaming agent metering pump 50 and supply the foaming agent E to the liquid channel 30 at a pressure higher than the liquid pressure LP of the liquid L1 flowing through the liquid channel 30. Furthermore, the foaming agent metering pump 50 may be of variable volume or fixed volume, but a variable volume type is preferred. By varying the volume, the predetermined amount of foaming agent E supplied can be varied. The variable volume control of the foaming agent metering pump 50 is preferably composed of a known control device equipped with a CPU (microprocessor), memory, input port, output port, etc., and may be composed of a personal computer or it may be varied manually.

[0028] In the foaming agent flow path 12, an on-off valve 60 is provided downstream of the foaming agent metering pump 50. The on-off valve 60 controls the addition of foaming agent E to liquid L1 by opening and closing it. When the on-off valve 60 is opened, it supplies the foaming agent E flowing through the foaming agent flow path 12 to liquid L1. On the other hand, when the on-off valve 60 is closed, it stops the supply of foaming agent E to liquid L1. The on-off valve 60 is composed of, for example, a solenoid valve.

[0029] A control unit 61 is connected to the on-off valve 60, which controls the opening or closing of the on-off valve 60. The control unit 61 receives pump drive information DI of the liquid pump 40 from the pump drive detection unit 41 and controls the on-off valve 60 to open according to the driving status of the liquid pump 40. Specifically, it controls the on-off valve 60 to open when the driving position of the liquid pump 40 reaches a predetermined position. When the on-off valve 60 is opened, a predetermined amount of foaming agent E is supplied to the liquid flow path 30 as described above. As described above, the liquid pump 40 is driven periodically. When the drive unit of the liquid pump 40 (drive position) reaches a predetermined position, the on-off valve 60 opens, and at the same timing in that cycle, the foaming agent E is supplied to the liquid L1. Here, the liquid pump 40 supplies liquid L to the flow path 30 with almost the same behavior (i.e., almost the same pressure and the same flow rate) at the same timing in the cycle. Therefore, when a predetermined amount (i.e., a fixed amount) of foaming agent is supplied to the flow path 30 at that timing, the supply of foaming agent E to liquid L1 becomes stable. In other words, in this embodiment, instead of controlling the liquid flow path 30 in response to the liquid pressure, the control is performed to open the on-off valve 60 when the drive unit of the liquid pump 40 reaches a predetermined position, thereby enabling a stable supply of the foaming agent E to the liquid L1. Furthermore, by controlling the valve 60 to open when it reaches a predetermined position and then closing it, the opening and closing of the valve will be repeated.

[0030] The predetermined position described above is not particularly limited, but if the liquid pump 40 is a reciprocating pump such as a syringe pump, it may be the top dead center, the bottom dead center, or a specific position between these, but it is preferable that it be either the top dead center or the bottom dead center. When the liquid reaches the top dead center or the bottom dead center, the pressure of the liquid L1 supplied to the liquid flow path 30 decreases. Therefore, if the predetermined position is the top dead center or the bottom dead center, the foaming agent E will be supplied at the timing when the pressure decreases, making it easier to mix the foaming agent E with the liquid L1. Furthermore, in a reciprocating pump, the above-mentioned predetermined position does not have to be just one location during one cycle in which the drive unit moves from top dead center to bottom dead center and then from bottom dead center to top dead center; there may be two or more locations. For example, both top dead center and bottom dead center may be set to predetermined positions. Furthermore, in the case of a rotary pump, the predetermined position can similarly be set to a specific position n° (where n is any position between 0 and 360°) within the rotation period (0 to 360°).

[0031] The control unit 61 may control the drive unit of the liquid pump 40 to open the on-off valve 60 once per cycle, or to open the on-off valve 60 once every two cycles, or to open the on-off valve 60 once every n cycles (where n is an integer of 3 or more). Alternatively, the control unit 61 may control the drive unit of the liquid pump 40 to open the on-off valve 60 multiple times within one cycle, for example, to open it once every half cycle. Note that opening the valve once per cycle means, for example, that if the top dead center is set to a predetermined position, the valve will open each time the top dead center is reached. The same applies to the bottom dead center. Furthermore, if, for example, a specific position between the top dead center and the bottom dead center is defined as the predetermined position, then it is not necessary to open the on-off valve 60 in any case when the drive unit reaches the predetermined position. Instead, it is preferable to control the valve to open either when the drive unit moves from the top dead center to the bottom dead center, or from the bottom dead center to the top dead center. Furthermore, in a double-acting type with multiple drive units (for example, a double-acting plunger pump), the on-off valve may be controlled based on the drive of one of the drive units, or it may be controlled based on the drive of multiple drive units. When controlled based on the drive of multiple drive units, for example, the valve may be opened each time the drive unit of each drive unit is positioned in a predetermined location.

[0032] The control unit 61 controls the on-off valve 60 to close when a predetermined amount of foaming agent E is added from the foaming agent metering pump 50 to the liquid L1 in the liquid channel 30. In this way, by closing the on-off valve 60 when a predetermined amount of foaming agent E is added from the foaming agent metering pump 50 to the liquid L1 in the liquid channel 30, a predetermined amount (predetermined volume) of foaming agent E can be stably supplied to the liquid L1 flowing through the liquid channel 30 without adding any excess foaming agent E. Here, the control unit 61 may measure the amount of foaming agent E discharged from the foaming agent metering pump 50 and close the valve when it determines that a predetermined amount of foaming agent E has been added to the liquid L1 when the amount discharged reaches a predetermined amount, or it may close the valve after a certain period of time has elapsed since opening, thereby adding a predetermined amount of foaming agent E to the liquid L1. Alternatively, the control unit 61 may detect the operation of the foaming agent metering pump 50 and close the valve when it determines that all of the predetermined amount of foaming agent E measured by the foaming agent metering pump 50 has been added.

[0033] Furthermore, the control unit 61 receives the liquid pressure LP of the liquid L1 flowing through the liquid channel 30, measured by the liquid channel pressure gauge 31, and controls the on-off valve 60 not to open if the measured pressure LP is lower than a predetermined value. By controlling the control unit 61 and not opening the on-off valve 60 when the measured pressure LP is lower than a predetermined value, it is possible to prevent the addition of the foaming agent E when only a small amount of liquid L1 is flowing through the liquid channel 30. Situations where the measured pressure LP is lower than a predetermined value include when the foaming agent addition device 10 is started, when it is stopped, and when the liquid channel 30 is clogged. The predetermined value of the measured pressure LP is preferably lower than the fluctuation of the pulsation of the liquid pump 40, for example, it can be set to 3 MPa.

[0034] Furthermore, the control unit 61 receives the liquid pressure LP of the liquid L1 flowing through the liquid channel 30, measured by the liquid channel pressure gauge 31, and the blowing agent pressure EP of the blowing agent E flowing through the blowing agent channel 12, measured by the blowing agent channel pressure gauge 81, and controls the blowing agent pressurizing pump 80 so that the blowing agent pressure EP is lower than the liquid pressure LP.

[0035] The amount of blowing agent E supplied to the liquid L1 flowing through the liquid channel 30 is preferably 0.05 to 5.0% by volume relative to the liquid L1, more preferably 0.1 to 4.5%, and even more preferably 0.15 to 4.0%. By keeping the amount of blowing agent E supplied within the above range, it becomes possible to incorporate an appropriate amount of blowing agent into the polyol, etc., and the polyurethane foam can be properly foamed. The amount of blowing agent E supplied to the liquid L1 flowing through the liquid channel 30 is preferably adjusted depending on the blowing agent E used. For example, if the blowing agent E is carbon dioxide, it is preferably 0.2 to 2.0%, and if the blowing agent E is a mixed gas of hydrofluoroolefin and carbon dioxide, it is preferably 0.4 to 3.5%.

[0036] (Spray foaming machine) As shown in Figure 2, the spray foaming machine 1 is equipped with the foaming agent addition device 10 described above. In this embodiment, the spray foaming machine 1 is a device for forming polyurethane foam. However, in the present invention, the spray foaming machine is not limited to a device for forming polyurethane foam, but may be a device for forming other types of foam. As described above, rigid polyurethane foam is preferred. Furthermore, the spray foaming machine 1 is a spray foaming machine for on-site application, and is brought to the construction site where the polyurethane foam is to be applied, and is a device for forming the polyurethane foam at the construction site.

[0037] The spray foaming machine 1, in addition to the foaming agent addition device 10, further includes the liquid flow path 30 (hereinafter also referred to as the first liquid flow path 30) and the liquid pump 40 (hereinafter also referred to as the first liquid pump 40). The spray foaming machine 1 also includes a second liquid flow path 32 through which a liquid L2 different from the liquid L1 flows, and a liquid pump 42 (hereinafter also referred to as the second liquid pump 42) that delivers the liquid L2 to the second liquid flow path 32. The first and second liquid pumps 40 and 42 are connected to a liquid container (not shown) such as a drum, and deliver the liquids L1 and L2 drawn from the liquid container to the first and second liquid flow paths 30 and 32, respectively.

[0038] As described above, polyurethane foam can be formed by mixing a liquid containing a polyol and a liquid containing a polyisocyanate, then foaming and curing the mixture. The liquid L1 flowing through the first liquid channel 30 is either the liquid or the liquid, and the liquid L2 flowing through the second liquid channel 32 is the other of the liquid. Preferably, liquid L1 is the liquid containing the polyol and liquid L2 is the liquid containing the polyisocyanate.

[0039] The spray foaming machine 1 is equipped with a spray gun 70. The spray gun 70 is equipped with a discharge section 70A and a mixing section 70B. In the mixing section 70B, the first and second liquid channels 30 and 35 are merged. Liquids 1 and 2 flowing through the first and second liquid channels 30 and 32 are mixed in the mixing section 70B, and the mixture (urethane resin composition) is sprayed from the discharge section 70A. At this time, the urethane resin composition is preferably sprayed onto the target surface of a building or structure, such as the roof, walls, or floor. The sprayed urethane resin composition foams and hardens to become polyurethane foam. Polyurethane foam is used, for example, as an insulating material.

[0040] In the spray foaming machine 1 described above, a liquid L1 obtained by appropriately mixing the foaming agent E using the foaming agent addition device 10 is used as the raw material for polyurethane foam, so that polyurethane foam with good foaming properties and sprayability can be formed.

[0041] [Method for adding foaming agent] The method for adding the blowing agent E to the liquid L1 in the blowing agent addition device 10 of this embodiment will be explained in detail with reference to the flowchart in Figure 3. In the following explanation, the pressure, temperature, etc. will be explained using the case where the blowing agent E is carbon dioxide as a specific example, but if the blowing agent E is another substance, the pressure, temperature, etc. should be set according to the properties of that substance.

[0042] In step S1, the foaming agent E contained in the foaming agent container 11 is supplied to the foaming agent channel 12. It is preferable to maintain the temperature of the foaming agent E supplied to the foaming agent channel 12 in the range of -20 to 20°C. Furthermore, it is preferable to adjust the pressure inside the foaming agent channel 12 so that the pressure of the foaming agent E sent to the foaming agent metering pump 50 is in the range of 5 to 12 MPa.

[0043] Next, in step S2, the foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 is measured by the foaming agent pressure gauge 81. The obtained foaming agent pressure EP is transmitted to the control unit 61.

[0044] In step S3, the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 is measured by the liquid pressure gauge 31. The obtained liquid pressure LP is transmitted to the control unit 61.

[0045] Next, in step S4, the blowing agent E flowing through the blowing agent channel 12 is pressurized by the blowing agent pressurizing pump 80 so that the blowing agent pressure EP of the blowing agent E measured by the blowing agent pressure gauge 81 is lower than the liquid pressure LP measured by the liquid channel pressure gauge 31. Specifically, the control unit 61, which receives the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 measured by the liquid channel pressure gauge 31 and the blowing agent pressure EP of the blowing agent E flowing through the blowing agent channel 12 measured by the blowing agent pressure gauge 81, compares the liquid pressure LP and the blowing agent pressure EP, and controls the blowing agent pressurizing pump 80 so that the blowing agent pressure EP is lower than the liquid pressure LP.

[0046] Next, in step S5, the pump drive detection unit 41 detects the operation of the liquid pump 40. Specifically, the pump drive detection unit 41 detects the drive position of the drive unit of the liquid pump 40 for pressurizing the liquid L1 flowing through the liquid channel 30, and obtains pump drive information DI related to the detected operation of the liquid pump 40. The pump drive detection unit 41 is preferably a laser applicator capable of continuously measuring the drive position of the drive unit of the liquid pump 40. The obtained pump drive information DI is transmitted to the control unit 61.

[0047] Next, in step S6, a predetermined amount of foaming agent E to be supplied to the liquid flow path 30 is measured using the foaming agent metering pump 50.

[0048] Next, in step S7, the addition of the foaming agent E to the liquid L1 is controlled by opening and closing the on-off valve 60. In the process of controlling the addition of the foaming agent E by opening and closing the on-off valve 60, the control unit 61 controls the opening of the on-off valve 60 according to the driving status of the liquid pump 40 detected by the pump drive detection unit 41. Specifically, the control unit 61 receives pump drive information DI of the liquid pump 40 from the pump drive detection unit 41, and when the driving position of the drive unit in the liquid pump 40 reaches a predetermined position, it controls the opening of the on-off valve 60.

[0049] However, steps S1 to S7 described above are merely examples of control and may be performed in any order as long as they do not contradict the essence of the present invention. For example, step S2 may be performed simultaneously with each of the steps from S3 to S6, or after any of the steps from S3 to S6. For example, steps S5 and S6 may be performed in reverse order or simultaneously. Also, steps S2 to S4 and steps S5 to S6 may be performed simultaneously. Steps S2 and S3 may also be performed in reverse order or simultaneously.

[0050] [Method for manufacturing foamed material] A foam can be formed by using the foaming agent addition device 10 according to the first embodiment of the present invention. The method for manufacturing polyurethane foam in this embodiment includes the steps S1 to S7 described above, and further includes the step of discharging a mixture prepared by mixing liquid L1, which is obtained by adding a foaming agent E to liquid L1 flowing through the liquid channel 30 in the foaming agent addition device 10, with liquid L2 in a spray foaming machine 1. Specifically, it includes the following steps (1) to (8). (1) A process of supplying the foaming agent E contained in the foaming agent container 11 to the foaming agent flow path 12. (2) A step of measuring the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 with a liquid pressure gauge 31. (3) A step of measuring the foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 with a foaming agent pressure gauge 81. (4) A step of pressurizing the foaming agent E flowing through the foaming agent channel 12 with the foaming agent pressurizing pump 80 so that the foaming agent pressure EP of the foaming agent E measured by the foaming agent pressure gauge 81 is lower than the liquid pressure LP measured by the liquid channel pressure gauge 31. (5) Steps to detect the operation of the liquid pump 40 using the pump drive detection unit 41. (6) A step of measuring a predetermined amount of foaming agent E to be supplied to the liquid channel 30 using a foaming agent metering pump 50. (7) A process of controlling the addition of foaming agent E to liquid L1 by opening and closing the on / off valve 60. (8) A step of discharging a mixture prepared by mixing liquid L1, which has been obtained by adding foaming agent E to liquid L1 flowing through the liquid channel 30 in the foaming agent addition device 10, with liquid L2 in the spray foaming machine 1.

[0051] As described above, in this embodiment, a pump drive detection unit 41 is provided to detect the operation of the liquid pump 40, thereby detecting the operation status of the liquid pump 40 and controlling it according to the operation status of the liquid pump 40. In this way, by controlling it according to the operation status of the liquid pump 40 rather than according to the liquid pressure in the liquid flow path 30, the foaming agent E can be stably supplied to the liquid L1 flowing through the liquid flow path 30 without being affected by the pulsation of the liquid pump 40. Furthermore, in this embodiment, by using a foaming agent metering pump 50 that supplies a predetermined amount of foaming agent E to the liquid L1 flowing through the liquid channel 30, a predetermined amount (predetermined volume) of foaming agent can be stably supplied to the liquid L1 flowing through the liquid channel 30. Furthermore, in this embodiment, by using the foaming agent pressurizing pump 80, the foaming agent pressure EP in the foaming agent flow path 12 is kept lower than the liquid pressure LP in the liquid flow path 30, thereby reducing the load on the foaming agent pressurizing pump 80, maintaining its function, and enabling a stable supply of the foaming agent.

[0052] [Second Embodiment] Next, a second embodiment of the present invention will be described in detail. In the second embodiment, the difference from the first embodiment is that, as shown in Figures 4 and 5, the foaming agent flow path 12 upstream of the on-off valve 60 is equipped with a flow rate adjustment mechanism 90 for adjusting the flow rate of the foaming agent E. The differences between the second embodiment and the first embodiment will be described below. Also, parts that are omitted from the description are the same as in the first embodiment. Furthermore, in the following description, components having the same configuration as in the first embodiment will be denoted by the same reference numerals.

[0053] The flow rate adjustment mechanism 90 may be configured to be located upstream of the on-off valve 60 and downstream of the foaming agent pressure pump 80 in the foaming agent flow path 12, as shown in Figure 4, or it may be configured to be located upstream of the on-off valve 60 and upstream of the foaming agent pressure pump 80 in the foaming agent flow path 12, as shown in Figure 5. The flow rate adjustment mechanism 90 adjusts the flow rate of foaming agent E to the foaming agent metering pump 50. The flow rate adjustment mechanism 90 can be a second on-off valve that controls the flow rate of foaming agent E flowing through the foaming agent flow path 12 upstream of the on-off valve 60 by opening and closing it. When the second on-off valve opens, the flow rate adjustment mechanism 90 supplies foaming agent E flowing through the foaming agent flow path 12 to the foaming agent metering pump 50. On the other hand, when the second on-off valve closes, the flow rate adjustment mechanism 90 stops the supply of foaming agent E to the foaming agent metering pump 50. The second on-off valve is composed of, for example, a solenoid valve. Furthermore, the flow rate adjustment mechanism 90 is preferably located closer to the on-off valve 60 so that it can be controlled more stably, and the configuration shown in Figure 4 is preferred.

[0054] The flow rate adjustment mechanism 90 is connected to an on-off valve control unit 61 that controls the opening or closing of the second on-off valve. The on-off valve control unit 61 controls the flow rate adjustment mechanism (second on-off valve) 90 according to the opening or closing status of the on-off valve 60. Specifically, when the on-off valve 60 is open, the flow rate adjustment mechanism 90 is closed. Furthermore, when the on-off valve 60 is closed, the flow rate adjustment mechanism 90 is opened to supply the foaming agent to the foaming agent metering pump 50. Then, before switching the on-off valve 60 back to open, or simultaneously with switching the on-off valve 60 to open, the flow rate adjustment mechanism 90 is closed. By controlling the opening and closing status of the flow rate adjustment mechanism 90 in this way, it is possible to control the flow path from the foaming agent container 11 to the on-off valve 60 so that it is not directly connected. In other words, by controlling the flow rate adjustment mechanism 90 so that it is not directly connected to the flow path from the foaming agent container 11 to the on-off valve 60, it is possible to prevent excessive addition of foaming agent E from the foaming agent container 11 to the liquid L1, even if the foaming agent pressure in the foaming agent container 11 becomes high.

[0055] The method for adding the foaming agent E to the liquid L1 in the foaming agent adding device 10 shown in Figure 4 of this embodiment is shown in the flowchart of Figure 6, and the method for adding the foaming agent E to the liquid L1 in the foaming agent adding device 10 shown in Figure 5 is shown in the flowchart of Figure 7. In the flowchart of Figure 6, before the step of measuring the foaming agent E with the foaming agent metering pump 80 (step S6), the process includes closing the on-off valve 60 and opening the flow rate adjustment mechanism 90 (step S10). Then, before the step of controlling the addition of the foaming agent E by opening and closing the on-off valve 60 (step S7), the process includes closing the flow rate adjustment mechanism 90 (step S11). Furthermore, the flowchart in Figure 7 includes a step (S10) in which the on-off valve 60 is closed and the flow rate adjustment mechanism 90 is opened, before the step (S1) in which the foaming agent E contained in the foaming agent container 11 is supplied to the foaming agent flow path 12. Then, before the step (S7) in which the addition of the foaming agent E is controlled by opening and closing the on-off valve 60, the flowchart includes a step (S11) in which the flow rate adjustment mechanism 90 is closed.

[0056] However, the steps shown in the flowcharts of Figures 6 and 7 are merely examples of control and may be performed in any order as long as they do not contradict the essence of the present invention. For example, step S2 may be performed simultaneously with steps S3 to S6 and steps S10 and S11, or after any of steps S3 to S6 and steps S10 and S11. For example, steps S5 and S6 may be performed in reverse order or simultaneously. Also, steps S2 to S4 and steps S5 to S6 may be performed simultaneously. Steps S2 and S3 may also be performed in reverse order or simultaneously.

[0057] As described above, in this embodiment, by providing the flow rate adjustment mechanism 90, the connection of the flow path from the foaming agent container 11 to the on-off valve 60 can be controlled, and even when the foaming agent container 11 is under high pressure, the differential pressure between the foaming agent E and the liquid pressure in the liquid flow path 30 can be adjusted. By adjusting the differential pressure between the foaming agent E and the liquid pressure in the liquid flow path 30, the foaming agent metering pump 50 can stably supply a predetermined amount (predetermined volume) of foaming agent to the liquid L1 flowing through the liquid flow path 30. In this embodiment, the flow rate adjustment mechanism 90 has been described as a second on-off valve, but other mechanisms may be used as long as they can adjust the flow rate of the foaming agent E.

[0058] [Other embodiments] As described above with reference to the first and second embodiments, the foaming agent addition apparatus, spray foaming machine, foaming agent addition method, and foam production method are examples of the present invention. The present invention is not limited to the configuration of the above embodiments, and various improvements and modifications are possible without departing from the spirit of the present invention, and components may be added as appropriate. For example, before the step of measuring a predetermined amount of foaming agent E to be supplied to the liquid channel 30 using the foaming agent metering pump 50 (step S6), the process includes a step of pressurizing the pressure of the foaming agent E flowing through the foaming agent channel 12 to a predetermined pressure using the foaming agent pressurizing pump 80. In the process of pressurizing the foaming agent to a predetermined pressure using the foaming agent pressurizing pump 80, the pressure of the foaming agent E flowing through the foaming agent channel 12 may be measured using a foaming agent pressure gauge 81 installed between the foaming agent pressurizing pump 80 and the foaming agent metering pump 50. Measuring the pressure with the foaming agent pressure gauge 81 improves the accuracy of pressurizing the foaming agent to a predetermined pressure using the foaming agent pressurizing pump 80, and enables a more stable supply of foaming agent E to the foaming agent metering pump 50 located downstream.

[0059] For example, in a foaming agent addition method, in step S7, where the addition of foaming agent E to liquid L1 is controlled by opening and closing a shut-off valve 60, if the measured pressure LP of the liquid pressure gauge 31 is lower than a predetermined value, the shut-off valve 60 may be controlled not to open. By including step S20 in the foaming agent addition method, when the foaming agent addition device 10 is started, stopped, or when the liquid flow path 30 is clogged, and the amount of liquid L1 flowing through the liquid flow path 30 is small, the foaming agent E will not be added at a stable rate, so control can be implemented to prevent addition. The predetermined value of the measured pressure LP is preferably a value lower than the fluctuation of the pulsation of the liquid pump 40, for example, it can be set to 3 MPa.

[0060] For example, as shown in Figure 8, the foaming agent addition device 10 can be configured to include a check valve 62 between the foaming agent metering pump 50 and the on / off valve 60 to prevent backflow of the foaming agent E flowing through the foaming agent channel 12. [Explanation of Symbols]

[0061] 1. Spray foaming machine 10. Foaming agent addition device 11. Effervescent agent container 12 Foaming agent channel 30 Liquid channel (first liquid channel) 31 Liquid flow pressure gauge 32 Second liquid channel 40. Liquid pump (first liquid pump) 41 Pump drive detection unit 41 42. Liquid pump (second liquid pump) 50 Foaming agent metering pump 60 Shut-off valves 61 Control Unit 62 Check valve 70 Spray gun 70A discharge part 70B Mixing section 80 Foaming agent pressurizing pump 81 Foaming agent pressure gauge 90 Flow rate adjustment mechanism E Foaming agent L1, L2 liquid

Claims

1. A foaming agent adding device for adding a foaming agent to a liquid supplied by a liquid pump and flowing through a liquid channel, A liquid flow path pressure gauge for measuring the pressure of the liquid flowing through the liquid flow path, A pump drive detection unit for detecting the operation of the aforementioned liquid pump, A foaming agent container for containing the aforementioned foaming agent, A foaming agent channel through which the foaming agent supplied from the foaming agent container flows, A foaming agent pressure gauge for measuring the pressure of the foaming agent flowing through the foaming agent channel, A foaming agent pressurizing pump pressurizes the foaming agent flowing through the foaming agent channel so that the pressure of the foaming agent measured by the foaming agent pressure gauge is lower than the liquid pressure measured by the liquid channel pressure gauge. A foaming agent metering pump that supplies a predetermined amount of the foaming agent to the liquid flow path, A valve for controlling the addition of the foaming agent to the liquid by opening and closing it, A foaming agent additive device comprising: a control unit that controls the opening of the on / off valve according to the driving status of the liquid pump detected by the pump drive detection unit; and a control unit that controls the opening of the on / off valve.

2. The foaming agent adding apparatus according to claim 1, wherein the control unit opens the on-off valve when the driving position of the liquid pump reaches a predetermined position.

3. The foaming agent adding apparatus according to claim 1 or 2, wherein the control unit controls the closing of the on / off valve when a predetermined amount of the foaming agent is added to the liquid.

4. The foaming agent metering pump is a positive displacement pump, as described in any one of claims 1 to 3, for the foaming agent adding apparatus.

5. The foaming agent metering pump is a reciprocating pump, according to any one of claims 1 to 4.

6. The foaming agent pressurizing pump is a pump that continuously pressurizes the foaming agent, as described in any one of claims 1 to 5.

7. The foaming agent pressurizing pump is either an axial pump or a gear pump, according to any one of claims 1 to 6.

8. The foaming agent adding apparatus according to any one of claims 1 to 7, wherein the liquid comprises a polyol or a polyisocyanate.

9. The foaming agent adding apparatus according to any one of claims 1 to 8, wherein the liquid contains a filler.

10. The blowing agent, comprising carbon dioxide, is a blowing agent adding apparatus according to any one of claims 1 to 9.

11. The foaming agent adding apparatus according to any one of claims 1 to 10, wherein the control unit controls the on / off valve not to open when the liquid pressure measured by the liquid flow path pressure gauge is lower than a predetermined value.

12. The foaming agent adding apparatus according to any one of claims 1 to 11, further comprising a flow rate adjustment mechanism for adjusting the flow rate of the foaming agent in the foaming agent flow path upstream of the on / off valve.

13. The foaming agent addition apparatus according to claim 12, wherein the flow rate adjustment mechanism is a second on-off valve that controls the flow rate of the foaming agent flowing in the foaming agent channel upstream of the on-off valve by opening and closing it.

14. A spray foaming machine equipped with a foaming agent addition device according to any one of claims 1 to 13.

15. A method for adding a foaming agent to a liquid supplied by a liquid pump and flowing through a liquid channel, A process of supplying the foaming agent contained in the foaming agent container to the foaming agent flow path, A step of measuring the pressure of the foaming agent flowing through the foaming agent channel using a foaming agent pressure gauge, A step of measuring the pressure of the liquid flowing through the liquid channel using a liquid channel pressure gauge, A step of pressurizing the foaming agent flowing through the foaming agent channel with a foaming agent pressurizing pump so that the pressure of the foaming agent measured by the foaming agent pressure gauge is lower than the liquid pressure measured by the liquid channel pressure gauge, The process involves detecting the operation of the liquid pump using a pump drive detection unit, A step of measuring a predetermined amount of the foaming agent to be supplied to the liquid channel using a foaming agent metering pump, The process includes controlling the addition of the foaming agent to the liquid by opening and closing a valve, A method for adding a foaming agent, wherein, in the step of controlling the addition of the foaming agent by opening and closing an on-off valve, the control unit controls the opening of the on-off valve according to the driving status of the liquid pump detected by the liquid pump drive detection unit.

16. The method for adding a foaming agent according to claim 15, wherein, in the step of controlling the addition of the foaming agent by opening and closing an on-off valve, the on-off valve is controlled not to open when the measured pressure of the liquid pressure gauge is lower than a predetermined value.

17. A method for producing a foam, comprising the step of adding a foaming agent to a liquid flowing through a liquid channel using the foaming agent addition method described in claim 15 or 16.

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