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 enable the stable addition of a foaming agent to a liquid without causing excessive addition. [Solution] The system includes a liquid flow path pressure gauge 31 for measuring the liquid pressure LP of liquid L1, a foaming agent flow path 12 for flowing foaming agent E supplied from a foaming agent container 11, a foaming agent pressurizing pump 80 for pressurizing the foaming agent pressure EP in the foaming agent flow path 12 to a predetermined pressure, a foaming agent flow path pressure gauge 90 for measuring the foaming agent pressure EP of the foaming agent E flowing through the foaming agent flow path 12, an on-off valve 50 for controlling the addition of foaming agent E to liquid L1 by opening and closing, a flow rate adjustment mechanism 60 for adjusting the flow rate of foaming agent E in the foaming agent flow path 12 upstream of the on-off valve 50, and a control unit 51 that opens the on-off valve 50 when the foaming agent pressure EP measured by the foaming agent flow path pressure gauge 90 is higher than the liquid pressure LP measured by the liquid flow path pressure gauge 31.

Description

Technical Field

[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 a polyurethane foam by mixing polyol and isocyanate on-site and spraying the mixture to foam it on the roof, wall surface, floor, etc. of a building or structure 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 connected to a liquid flow path for supplying polyol or isocyanate is provided, and carbon dioxide or the like as a foaming agent is added to polyol or isocyanate in the liquid flow path through the foaming agent flow path from a tank or the like. 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 under pressure, 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 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 is used (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] In conventional foaming agent additive systems, the condition for adding the foaming agent is that the foaming agent pressure must be higher than the liquid pressure. The addition of the foaming agent to the liquid is controlled by detecting the liquid pressure in the liquid flow path and using the pressure difference between the liquid pressure and the foaming agent pressure as the driving force for foaming agent addition. In control systems that use the pressure difference between liquid pressure and foaming agent pressure as the driving force for foaming agent addition, if the foaming agent pressure becomes high, such as in summer when the flow path is connected from the foaming agent container to the on / off valve that controls the amount of foaming agent added to the liquid, the foaming agent, which is at a higher pressure than the liquid pressure, tends to be added in excess, making it difficult to adjust the amount of foaming agent added.

[0006] Therefore, the object of the present invention is to provide a foaming agent addition apparatus, a spray foaming machine, a foaming agent addition method, and a foam manufacturing method that can stably add a foaming agent to a liquid without causing excessive addition under high temperatures such as in summer. [Means for solving the problem]

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

[13] . [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, comprising: a liquid channel pressure gauge for measuring the liquid pressure of the liquid flowing through the liquid channel; 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 pressurizing pump for pressurizing the foaming agent pressure in the foaming agent channel to a predetermined pressure; a foaming agent channel pressure gauge for measuring the foaming agent pressure of the foaming agent flowing through the foaming agent channel; an on-off valve for controlling the connection between the foaming agent channel and the liquid channel by opening and closing, and controlling the addition of the foaming agent to the liquid by opening and closing; a flow rate adjustment mechanism for adjusting the flow rate of the foaming agent in the foaming agent channel upstream of the on-off valve; and a control unit for opening the on-off valve when the foaming agent pressure measured by the foaming agent channel pressure gauge is higher than the liquid pressure measured by the liquid channel pressure gauge. [2] 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, the foaming agent addition apparatus according to [1]. [3] The foaming agent pressurizing pump pressurizes the foaming agent so that the pressure of the foaming agent is a predetermined higher pressure than the liquid pressure, as described in [1] or [2]. [4] The foaming agent adding apparatus according to any one of [1] to [3], wherein the control unit controls the opening of the on-off valve and then controls the closing of the on-off valve after a predetermined time has elapsed. [5] 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 [4]. [6] The foaming agent pressurizing pump is either an axial pump or a gear pump, as described in any of [1] to [5]. [7] The foaming agent adding apparatus according to any one of [1] to [6], further comprising a pump drive detection unit for detecting the operation of the liquid pump, wherein when the pump drive detection unit detects that the liquid pump has reached the top dead center or the bottom dead center, the control unit controls the opening of the on-off valve. [8] The blowing 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]. A spray foaming machine equipped with a foaming agent addition device as described in any of

[11] [1] to

[10] .

[12] 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 foaming agent pressure of the foaming agent flowing through the foaming agent channel with a foaming agent channel pressure gauge; measuring the liquid pressure of the liquid flowing through the liquid channel with a liquid channel pressure gauge; pressurizing the foaming agent pressure in the foaming agent channel to a predetermined pressure with a foaming agent pressurizing pump; controlling the connection between the foaming agent channel and the liquid channel by opening and closing an on-off valve, and controlling the addition of the foaming agent to the liquid by opening and closing the on-off valve; and adjusting the flow rate of the foaming agent by a flow rate adjustment mechanism provided in the foaming agent channel upstream of the on-off valve, wherein in the step of controlling the addition of the foaming agent by opening and closing an on-off valve, when the foaming agent pressure measured by the foaming agent channel pressure gauge is higher than the liquid pressure measured by the liquid channel pressure gauge, the control unit controls the on-off valve to open. 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

[13] and

[12] . [Effects of the Invention]

[0008] The present invention provides a foaming agent addition apparatus, a spray foaming machine, a foaming agent addition method, and a foam production method that enable the stable addition of a foaming agent to a liquid without causing excessive addition under high temperatures such as in summer. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram (part 1) showing a foaming agent addition apparatus according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram showing a spray foaming machine according to the first embodiment of the present invention. [Figure 3] This is a flowchart showing a method for adding a foaming agent according to the first embodiment of the present invention. [Figure 4] This is a schematic diagram (part 2) showing a foaming agent addition apparatus according to the first embodiment of the present invention. [Figure 5] This is a schematic diagram (part 1) showing a foaming agent addition apparatus according to a second embodiment of the present invention. [Figure 6] This is a schematic diagram (part 2) showing a foaming agent addition apparatus according to a second embodiment of the present invention. [Figure 7] Flowchart showing a foaming agent addition method according to a second embodiment of the present invention [Figure 8] This is a schematic diagram showing a foaming agent addition apparatus according to another embodiment 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 Figure 1, the foaming agent addition device 10 according to the first embodiment is a device for mixing a foaming agent E with the liquid L1 flowing through the liquid channel 30.

[0011] <Liquid> The liquid L1 is not particularly limited, but a foam raw material, which is a raw material for the foam, is preferable. The foaming agent adding device 10 can produce a foam by mixing a foaming agent E into the liquid L1 which is a foam raw material. Examples of the foam include polyurethane foam, phenolic foam, polystyrene foam, etc. Therefore, as the liquid L1, any material that can be a raw material for these foams may be used. Among the above, polyurethane foam is preferable from the viewpoints of ease of production, curing rate, foaming property, etc. Further, it is more preferable that the polyurethane foam is a rigid polyurethane foam. By using a rigid polyurethane foam, self - adhesiveness, heat insulation property, mechanical strength, etc. tend to be good.

[0012] A urethane resin composition for forming a polyurethane foam is generally prepared by mixing one liquid containing a polyol and two liquids containing a polyisocyanate. The urethane resin composition is foamed by a foaming agent E mixed into the composition and cured to form a polyurethane foam. The foaming agent E may be mixed into either the one liquid or the two liquids, but it is preferably mixed into the one liquid from the viewpoints of stability, etc. That is, the foaming agent adding device 10 preferably mixes the liquid - state foaming agent E into a liquid (one liquid or two liquids) containing either a polyol or a polyisocyanate, and it is more preferable to mix the foaming agent E into the liquid (one liquid) containing a polyol. The liquid (one liquid) containing a polyol is preferably a polyol composition containing a catalyst and a foam stabilizer in addition to the polyol, and may further contain a foaming agent. The foaming agent pre - contained in the one liquid (polyol composition) in this way is also referred to as an "internally added foaming agent" in order to distinguish it from the above - mentioned foaming agent E.

[0013] In addition, the urethane resin composition for forming the polyurethane foam may contain a filler. By including a filler in the urethane resin composition, the flame retardancy of the resulting polyurethane foam is improved. It is preferable to mix the filler into a liquid (one-component or two-component) containing either a polyol or a polyisocyanate, and it is more preferable to mix the filler into the liquid containing the polyol (one-component). The filler is included as a solid component in the liquid raw material composition and is generally a component present in the form of granules or powder in the raw material composition. The filler may be a solid at normal temperature (23 °C) and normal pressure (1 atm) and does not dissolve in the liquid raw material composition. Examples of the filler include solid flame retardants and anti-settling agents. Examples of the 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. It is preferable that it is at least one selected from the group consisting of red phosphorus-based flame retardants, boron-containing flame retardants, and bromine-containing flame retardants.

[0014] In addition to the curing catalyst, foam stabilizer, and filler, the polyol composition can also contain various additives such as flame retardants (solid flame retardants, liquid flame retardants), antioxidants, heat stabilizers, metal deactivators, 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 foaming agent container 11, a foaming agent flow path 12, a foaming agent pressurizing pump 80, a foaming agent flow path pressure gauge 90, an on-off valve 50, a flow rate adjustment mechanism 60, and a control unit 51. The foaming agent addition device 10 is a device for adding a foaming agent E to the liquid L flowing through the 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. 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 liquid 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 51.

[0021] The foaming agent container 11 contains the foaming agent E. 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). By heating with the heater, the internal pressure of the foaming agent container 11 increases, thereby reducing the burden on the foaming agent pressurizing pump 80 to pressurize, and making it easier to deliver the foaming agent E to the foam flow path 12 under high pressure.

[0022] 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, 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.

[0023] A foaming agent flow path pressure gauge 90 is provided in the foaming agent flow path 12. The foaming agent flow path pressure gauge 90 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 90 transmits the measured foaming agent pressure EP to the control unit 51.

[0024] 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 51 and is located upstream of the on-off valve 50 in the foaming agent flow path 12. The foaming agent pressure pump 80 pressurizes the foaming agent pressure EP in the foaming agent flow path 12 to a predetermined pressure that is higher than the liquid pressure LP of the liquid L1 flowing through the liquid flow path 30. Specifically, the foaming agent pressurizing pump 80 pressurizes the foaming agent so that the foaming agent pressure EP is a predetermined higher pressure than the liquid pressure LP. Here, the predetermined higher pressure is a value set according to the type, properties, and amount of foaming agent E and liquid L1 used, and can be set as appropriate. For example, the predetermined higher pressure is set so that the foaming agent pressure EP is 0.05 to 5.00 MPa higher than the liquid pressure LP. The foaming agent pressurizing pump 80 is preferably a pump capable of pressurizing and supplying the foaming agent E at a stable pressure, from the viewpoint of enabling the supply of the foaming agent E to the liquid passage 30 at a constant pressure via the on-off valve 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.

[0025] The foaming agent pressurizing pump 80 is preferably controlled by the control unit 51. The control unit 51 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 flow path pressure gauge 90, and controls the foaming agent pressurizing pump 80 so that the foaming agent pressure EP of the foaming agent E flowing through the foaming agent flow path 12 becomes higher than the pressure LP of the liquid L1 flowing through the liquid flow path 30. Furthermore, when the foaming agent pressure EP reaches a specified value, the control unit 51 closes the flow rate adjustment mechanism 60 as described later, so it is preferable to control the pump 80 to stop supplying the foaming agent E to the on-off valve 50 at that timing. The control unit 51 may restart the stopped foaming agent pressurizing pump 80 at the timing when the flow rate adjustment mechanism 60 is opened. 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 on-off valve 50 located downstream.

[0026] A flow rate adjustment mechanism 60 is provided in the foaming agent flow path 12. In one embodiment, as shown in Figure 1, the flow rate adjustment mechanism 60 may be configured to be located upstream of the on-off valve 50 and downstream of the foaming agent pressurizing pump 80 in the foaming agent flow path 12. The flow rate adjustment mechanism 60 adjusts the flow rate of the foaming agent E in the foaming agent flow path 12. The flow rate adjustment mechanism 60 can be a second on-off valve that controls the flow rate of the foaming agent E flowing in the foaming agent flow path 12 upstream of the on-off valve 50 by opening and closing it. The flow rate adjustment mechanism 60 prevents an excess of the foaming agent E flowing in the foaming agent flow path 12 by opening the second on-off valve, and stably supplies the foaming agent E to the liquid L1 flowing in the liquid flow path 30. On the other hand, the flow rate adjustment mechanism 60 stops the supply of the foaming agent E toward the on-off valve 50 by closing the second on-off valve. The second on-off valve is composed of, for example, a solenoid valve.

[0027] In the foaming agent flow path 12, an on-off valve 50 is provided downstream of the foaming agent pressurizing pump 80 and the flow rate adjustment mechanism 60. The on-off valve 50 controls the connection between the foaming agent flow path 12 and the liquid flow path 30 by opening and closing, and controls the addition of the foaming agent E to the liquid L1 by opening and closing. When the on-off valve 50 is opened, it supplies the foaming agent E flowing through the foaming agent flow path 12 to the liquid L1. On the other hand, when the on-off valve 50 is closed, it stops the supply of the foaming agent E to the liquid L1. The on-off valve 50 is composed of, for example, a solenoid valve.

[0028] A control unit 51 is connected to the flow rate adjustment mechanism 60 and the on-off valve 50 to control the opening or closing of the flow rate adjustment mechanism 60 and the on-off valve 50. The control unit 51 receives the foaming agent pressure EP from the foaming agent flow path pressure gauge 90 and the liquid pressure LP from the liquid flow path pressure gauge 31, and controls the flow rate of the foaming agent E flowing through the foaming agent flow path 12 by the flow rate adjustment mechanism (second on-off valve) 60 and the on-off valve 50 according to the received foaming agent pressure EP and liquid pressure LP. The control unit 51 controls the on-off valve 50 to open when the foaming agent pressure EP is higher than the liquid pressure LP. In addition, the control unit 51 also controls the flow rate adjustment mechanism 60 along with the on-off valve 50.

[0029] Specifically, in the initial operation, with the on-off valve 50 closed and the flow rate adjustment mechanism 60 open, the foaming agent pressurizing pump 80 is driven to increase the foaming agent pressure EP. When the control unit 51 detects that the foaming agent pressure EP has risen to a specified value, it sends a control signal to the flow rate adjustment mechanism 60 and the on-off valve 50. Based on this control signal, the control unit 51 closes the flow rate adjustment mechanism 60 and opens the on-off valve 50 to supply the foaming agent E to the liquid flow path 30. After controlling the opening of the on-off valve 50, the on-off valve 50 is closed after a predetermined time has elapsed. Subsequently, the flow rate adjustment mechanism 60 is opened, and the foaming agent pressurizing pump 80 is driven to increase the foaming agent pressure EP to a specified value, and then the above operation is repeated. The specified value is a value set so that the foaming agent pressure EP is higher than the liquid pressure LP by the predetermined value mentioned above. Through the above control, the foaming agent E is supplied to the liquid channel 30 at a predetermined pressure higher than the liquid pressure LP for a predetermined time, so that a constant amount of foaming agent E can be supplied to the liquid channel 30. Furthermore, the flow rate adjustment mechanism 60 is provided, and more than one level of control is performed, which prevents the foaming agent container 11 and the foaming agent pressurizing pump 80 from being directly connected to the liquid flow path 30. This prevents excessive supply of foaming agent E, which is pressurized more than necessary in the foaming agent container 11 and the foaming agent flow path 12, to the liquid flow path 30, especially during the summer.

[0030] Furthermore, the control unit 51 may also receive the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 measured by the liquid channel pressure gauge 31, and control the on-off valve 50 not to open if the liquid pressure LP is lower than a predetermined value. By controlling the control unit 51 in this way, the on-off valve 50 is not opened when the liquid pressure LP is lower than a predetermined value, thereby preventing 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 liquid 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 liquid 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.

[0031] 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%.

[0032] (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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] [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. Note that the flowchart in Figure 3 is a diagram for explaining the blowing agent addition method, and the blowing agent addition method does not necessarily proceed in the order of the steps shown in Figure 3.

[0038] 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 foaming agent pressure EP toward the on-off valve 50 inside the foaming agent channel 12 to be in the range of 5 to 12 MPa.

[0039] 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 channel pressure gauge 90. The obtained foaming agent pressure EP is transmitted to the control unit 51.

[0040] In step S3, the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 is measured by the liquid channel pressure gauge 31. The obtained liquid pressure LP is transmitted to the control unit 51.

[0041] In step S4, the foaming agent pressure EP in the foaming agent flow path 12 is pressurized to a predetermined pressure by the foaming agent pressurizing pump 80. Specifically, the control unit 51 receives the liquid pressure LP of the liquid L1 flowing through the liquid flow path 30, measured by the liquid flow path pressure gauge 31, and the foaming agent pressure EP of the foaming agent E flowing through the foaming agent flow path 12, measured by the foaming agent flow path pressure gauge 90. The control unit 51 then compares the liquid pressure LP and the foaming agent pressure EP and controls the foaming agent pressurizing pump 80 so that the foaming agent pressure EP is higher than the liquid pressure LP by a predetermined value or more.

[0042] Furthermore, in step S5, the flow rate of the foaming agent E flowing through the upstream foaming agent flow path 12 is adjusted by a flow rate adjustment mechanism 60 provided in the foaming agent flow path 12 upstream of the on-off valve 50. Specifically, the flow rate of the foaming agent E flowing through the foaming agent flow path 12 upstream of the on-off valve 50 is controlled by opening or closing the flow rate adjustment mechanism 60.

[0043] In step S6, the addition of the foaming agent E to the liquid L1 is controlled by opening and closing the on-off valve 50. In the process of controlling the addition of the foaming agent E by opening and closing the on-off valve 50, the control unit 51, which receives the liquid pressure LP and the foaming agent pressure EP, compares the liquid pressure LP and the foaming agent pressure EP, and controls the on-off valve 50 to open when the foaming agent pressure EP is higher than the liquid pressure LP by a predetermined value or more.

[0044] [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 S6 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 (7). (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 foaming agent pressure EP of the foaming agent E flowing through the foaming agent channel 12 using a foaming agent channel pressure gauge 90. (3) A step of measuring the liquid pressure LP of the liquid L1 flowing through the liquid channel 30 with a liquid channel pressure gauge 31. (4) A step of pressurizing the foaming agent pressure EP in the foaming agent flow path 12 to a predetermined pressure using the foaming agent pressurizing pump 80. (5) A process of adjusting the flow rate of the foaming agent E by a flow rate adjustment mechanism 60 provided in the foaming agent flow path 12 upstream of the on / off valve 50. (6) A process of controlling the addition of foaming agent E to liquid L1 by opening and closing the on / off valve 50. (7) 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.

[0045] As described above, in this embodiment, by providing the flow rate adjustment mechanism 60, the blowing agent E can be stably supplied to the liquid L1 flowing through the liquid channel 30. For example, even if the blowing agent pressure EP becomes high under high temperatures such as in summer, the flow rate adjustment mechanism 60 can prevent the addition of an excess amount of blowing agent E to the liquid L1. Furthermore, since the blowing agent E is supplied to the liquid channel 30 at a predetermined pressure higher than the liquid pressure LP for a predetermined time, a constant amount of blowing agent E can be supplied to the liquid channel 30. In this embodiment, the flow rate adjustment mechanism 60 is 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. Even if the flow rate adjustment mechanism 60 is not a second on-off valve, as long as the flow rate can be adjusted by the flow rate adjustment mechanism 60, it is possible to prevent the foaming agent E from being supplied in excess to the liquid flow path 30. Furthermore, if a valve other than the second on-off valve is used as the flow rate adjustment mechanism 60, for example, instead of closing the flow rate adjustment mechanism 60 in the above configuration, it is preferable to adjust the flow rate of the foaming agent to a first amount that is relatively small, and instead of opening the flow rate adjustment mechanism 60, it is preferable to adjust the flow rate of the foaming agent to a second amount that is larger than the first amount.

[0046] In the above explanation, the flow rate adjustment mechanism 60 was described as being located upstream of the on-off valve 50 and downstream of the foaming agent pressurizing pump 80 in the foaming agent flow path 12, as shown in Figure 1. However, the flow rate adjustment mechanism 60 may also be located upstream of the on-off valve 50 and upstream of the foaming agent pressurizing pump 80 in the foaming agent flow path 12, as shown in Figure 4. In this configuration as well, the foaming agent container 11 is prevented from being directly connected to the liquid channel 30, thus preventing excessive supply of foaming agent E, which becomes excessively high pressure in the foaming agent container 11 and foaming agent channel 12, to the liquid channel 30 under high temperatures such as in summer. However, the flow rate adjustment mechanism 60 has the configuration shown in Figure 1, which allows it to be located downstream of the foaming agent pressurizing pump 80 and closer to the on-off valve 50, thus enabling stable control.

[0047] [Second Embodiment] Next, a second embodiment of the present invention will be described in detail. The difference in the second embodiment from the first embodiment is that, as shown in Figures 5 and 6, the liquid pump 40 is equipped with a pump drive detection unit 41. 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, the same reference numerals are used for components having the same configuration as in the first embodiment.

[0048] In this embodiment, the liquid pump 40 is provided 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 51. 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 of the drive unit 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 of the pump's drive unit during that reciprocating motion. Similarly, in a rotary pump, it is sufficient to detect the position of the drive unit during its 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).

[0049] The control unit 51 receives pump drive information DI for the liquid pump 40 from the pump drive detection unit 41 and controls the on-off valve 50 and the flow rate adjustment mechanism 60 to open or close them according to the blowing agent pressure EP and liquid pressure LP, as well as the driving status of the liquid pump 40. Specifically, when the blowing agent pressure EP rises to a specified value and the driving position of the liquid pump 40 reaches a predetermined position, the control unit 51 controls the on-off valve 50 to open and simultaneously controls the flow rate adjustment mechanism 60 to close. By opening the on-off valve 50, a certain amount of blowing agent E is supplied to the liquid flow path 30, similar to the first embodiment. As described above, the liquid pump 40 is driven periodically. When the drive unit of the liquid pump 40 reaches a predetermined position, the on-off valve 50 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 liquid 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 E is supplied to the liquid flow path 30 at that timing, the supply of foaming agent E to liquid L1 becomes stable. In other words, in this embodiment, by controlling the on-off valve 50 to open when the drive unit of the liquid pump 40 reaches a predetermined position, a stable supply of the foaming agent E to the liquid L1 becomes possible. Furthermore, by controlling the on-off valve 50 to open when it reaches a predetermined position and then closing it, the opening and closing of the on-off valve 50 will be repeated, similar to the first embodiment. Similarly, the flow rate adjustment mechanism (second on-off valve) 60 should also be controlled to repeatedly open and close, similar to the first embodiment. In other words, when the control unit 51 detects that the foaming agent pressure EP has risen to a specified value and receives pump drive information DI indicating that the drive position is driven to a predetermined position, it sends a control signal to the flow rate adjustment mechanism 60 and the on-off valve 50. Based on this control signal, the flow rate adjustment mechanism 60 is closed and the on-off valve 50 is opened to supply the foaming agent E to the liquid flow path 30. After that, the control is performed in the same manner as in the first embodiment.

[0050] 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°).

[0051] The control unit 51 may control the drive unit of the liquid pump 40 to open the on-off valve 50 once per cycle, or to open the on-off valve 50 once every two cycles, or to open the on-off valve 50 once every n cycles (where n is an integer of 3 or more). Alternatively, the control unit 51 may control the drive unit of the liquid pump 40 to open the on-off valve 50 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, it is not necessary to open the on-off valve 50 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.

[0052] The method for adding the foaming agent E to the liquid L1 in the foaming agent addition device 10 of this embodiment is shown in the flowchart of Figure 7. The flowchart in Figure 7 further includes a step (step S10) in which the pump drive detection unit 41 detects the operation of the liquid pump 40. In step S10, the pump drive detection unit 41 detects the operation of the liquid pump 40. This involves the pump drive detection unit 41 detecting the drive position of the drive unit of the liquid pump 40, which pressurizes the liquid L1 flowing through the liquid channel 30, and obtaining 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 51. Then, in the step (step S6) in which the addition of the foaming agent E is controlled by opening and closing the on-off valve 50, the control unit 51 also controls the opening of the on-off valve 50 according to the driving status of the liquid pump 40 detected by the pump drive detection unit 41. Specifically, it is preferable to control the opening of the on-off valve 50 when the control unit 51 detects that the foaming agent pressure EP has risen to a specified value, and when it receives pump drive information DI of the liquid pump 40 from the pump drive detection unit 41, and the driving position of the drive unit in the liquid pump 40 reaches a predetermined position.

[0053] 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.

[0054] [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, as shown in Figure 8, the foaming agent addition device 10 can be configured to include a check valve 52 between the foaming agent pressurizing pump 80 and the on-off valve 50 to prevent backflow of the foaming agent E flowing through the foaming agent channel 12. [Explanation of Symbols]

[0055] 1. Spray foaming machine 10. Foaming agent addition device 11. Foaming agent container 12 Foaming agent flow path 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 42. Liquid pump (second liquid pump) 50 Shut-off valves 51 Control Unit 52 Check valve 60 Flow rate adjustment mechanism 70 Spray gun 70A discharge part 70B Mixing section 80 Foaming agent pressurizing pump 90 Foaming agent flow path pressure gauge 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 liquid pressure of the liquid flowing through the liquid flow path, 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 pressurizing pump that pressurizes the foaming agent pressure in the foaming agent flow path to a predetermined pressure, A foaming agent flow path pressure gauge for measuring the foaming agent pressure of the foaming agent flowing through the foaming agent flow path, A valve controls the connection between the foaming agent channel and the liquid channel by opening and closing, and controls the addition of the foaming agent to the liquid by opening and closing, Upstream of the aforementioned on-off valve, the foaming agent flow path is provided with a flow rate adjustment mechanism for adjusting the flow rate of the foaming agent, A foaming agent additive apparatus comprising: a control unit that opens the on-off valve when the foaming agent pressure measured by the foaming agent flow path pressure gauge is higher than the liquid pressure measured by the liquid flow path pressure gauge.

2. The foaming agent addition apparatus according to claim 1, 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.

3. The foaming agent pressurizing pump pressurizes the foaming agent so that the pressure of the foaming agent is a predetermined higher pressure than the liquid pressure, as described in claim 1 or 2.

4. The foaming agent adding apparatus according to any one of claims 1 to 3, wherein the control unit controls the opening of the on-off valve, and then controls the closing of the on-off valve after a predetermined time has elapsed.

5. The foaming agent pressurizing pump is a pump that continuously pressurizes the foaming agent, as described in any one of claims 1 to 4.

6. The foaming agent pressurizing pump is either an axial pump or a gear pump, according to any one of claims 1 to 5.

7. The system further includes a pump drive detection unit for detecting the operation of the aforementioned liquid pump, The foaming agent adding apparatus according to any one of claims 1 to 6, wherein when the pump drive detection unit detects that the liquid pump has reached its top dead center or bottom dead center, the control unit controls the opening of the on-off valve.

8. The foaming agent adding apparatus according to any one of claims 1 to 7, wherein the liquid comprises a polyol or 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. A spray foaming machine equipped with a foaming agent addition device according to any one of claims 1 to 10.

12. 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 foaming agent pressure of the foaming agent flowing through the foaming agent channel using a foaming agent channel pressure gauge, A step of measuring the liquid pressure of the liquid flowing through the liquid channel using a liquid channel pressure gauge, A step of pressurizing the foaming agent pressure in the foaming agent channel to a predetermined pressure using a foaming agent pressurizing pump, The process involves controlling the connection between the foaming agent channel and the liquid channel by opening and closing a valve, and controlling the addition of the foaming agent to the liquid by opening and closing the valve. The process includes adjusting the flow rate of the foaming agent using a flow rate adjustment mechanism provided in the foaming agent flow path upstream of the aforementioned on-off 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 on-off valve to open when the pressure of the foaming agent measured by the foaming agent flow path pressure gauge is higher than the liquid pressure measured by the liquid flow path pressure gauge.

13. 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 12.

Images