Foaming device and foaming method

Abstract

This invention relates to a foaming apparatus (100) that mixes gas (G) into a viscous material of resin (R) and sprays out a foaming material (M) that disperses bubbles in the liquid of the viscous material. The foaming apparatus (100) includes: a piping (10) for the flow of resin and gas; a material supply unit (20) for supplying the viscous material to the piping; a gas supply unit (32) for supplying gas to the piping; a first gear pump (31) disposed midway through the piping; and a second gear pump (33) disposed downstream of the first gear pump on the piping, driven to rotate at a higher speed than the first gear pump, thereby causing gas to flow into the piping. The pipe contains a viscous material containing gas, which is fed downstream of the pipe. A third gear pump (34) is positioned downstream of the pipe from the second gear pump and is driven to rotate at the same speed as the second gear pump, thereby feeding the viscous material containing gas further downstream of the pipe. A mixer (41) is positioned downstream of the pipe from the third gear pump and disperses the bubbles in the viscous material in the liquid of the viscous material. An ejector (45) ejects the foaming material from the liquid of the viscous material, which has been dispersed by the mixer. A control unit (50) controls the ejection action of the foaming material.

Description

Technical Field

[0001] This invention relates to a foaming apparatus and a foaming method. Background Technology

[0002] Conventionally, foamed materials are used, which are structures in which a gas is mixed into a liquid such as a resin, which is used as an industrial sealing or vibration damping material, causing the foaming material containing air bubbles dispersed in the liquid to foam, harden, or solidify. Methods for generating foamed materials include chemical foaming, which involves mixing a main agent and a hardener to chemically foam the material, and mechanical foaming, which involves mechanically mixing a gas into a single liquid.

[0003] Chemical foaming utilizes a chemical reaction, making it difficult to control the foaming ratio due to environmental factors such as temperature, humidity, and the mixing state of two or more liquid agents. In contrast, mechanical foaming mechanically incorporates gas, thus being less affected by environmental factors and allowing for easier control of the foaming ratio. Therefore, mechanical foaming is preferred for sealing materials and vibration damping materials in electronic components, automotive parts, and other applications requiring more precise control of the foaming ratio.

[0004] Mechanical foaming devices mainly include plunger pumps and gear pumps. Gear pumps, because they can deliver liquid in a metered manner, make it easier to control the foaming ratio compared to plunger pumps.

[0005] For example, Patent Document 1 discloses a gear pump type mechanical foaming device, which includes: two gear pumps arranged in a flow path for discharging liquid resin; and a gas supply unit that supplies gas into the flow path via an air intake provided in the flow path between the two gear pumps. In this device, the rotational speed of the gears of each gear pump is controlled to generate a suction pressure (negative pressure) in the flow path between the gear pumps, thereby causing a desired amount of gas to flow into the flow path. In order to control the foaming ratio to an appropriate value, the suction pressure is adjusted by controlling the rotational speed of each gear pump.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2005-152710 Summary of the Invention

[0009] In the case of two pumps installed in the flow path as in Patent Document 1, the downstream pump not only needs to draw in liquid but also needs to draw in the gas required for foaming through the suction port via differential pressure. Therefore, it needs to rotate at a higher speed than the upstream pump. If the downstream pump is configured in this way, the load on the downstream pump is relatively increased. In such a case, due to variations in the speed and pressure of the downstream pump, the liquid-gas mixture pumped from the downstream pump may be sent back to the upstream side. Thus, the downstream pump is under load, making it difficult to deliver liquid and gas in a certain ratio in the foaming device, and making it difficult to obtain a stable foaming ratio.

[0010] Therefore, the purpose of this invention is to obtain a stable foaming ratio in foaming apparatus and foaming method.

[0011] A foaming apparatus according to one aspect of the present invention, which solves the above-mentioned problems, mixes gas into a viscous material and sprays out a foaming material that disperses bubbles in a liquid. The foaming apparatus includes a flow path, a material supply unit, a gas supply unit, a first gear pump, a second gear pump, a third gear pump, a mixer, an ejection unit, and a control unit. The flow path allows the viscous material and gas to circulate. The material supply unit supplies the viscous material into the flow path. The gas supply unit supplies gas into the flow path. The first gear pump is positioned midway through the flow path. The second gear pump is positioned downstream of the first gear pump and is driven to rotate at a higher speed than the first gear pump, thereby causing gas to flow into the flow path and feeding the gas-containing viscous material downstream of the flow path. The third gear pump is positioned downstream of the second gear pump and is driven to rotate at the same speed as the second gear pump, thereby feeding the gas-containing viscous material even further downstream of the flow path. The mixer is positioned downstream of the flow path from the third gear pump, dispersing air bubbles from the viscous material within the liquid viscous material. The ejector sprays out the foaming material generated by the dispersion of air bubbles in the liquid viscous material by the mixer. The control unit controls the ejection action of the foaming material.

[0012] Furthermore, one aspect of the foaming method of the present invention involves mixing gas into a viscous material to generate a foaming material in which bubbles are dispersed in the liquid of the viscous material. In the foaming method, a first gear pump, a second gear pump, and a third gear pump, arranged sequentially from upstream to downstream in a flow path through which the viscous material and gas flow, are used. The second gear pump is driven to rotate at a higher speed than the first gear pump. Furthermore, a suction pressure is generated between the first and second gear pumps within the flow path, causing the gas to be mixed in. The third gear pump is then driven to rotate at the same speed as the second gear pump, feeding the viscous material containing gas into a mixer positioned downstream of the third gear pump in the flow path, thereby dispersing the bubbles in the viscous material within the liquid of the viscous material. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating a foaming apparatus according to a first embodiment of the present invention.

[0014] Figure 2 This is a flowchart illustrating the foaming method according to the first embodiment of the present invention.

[0015] Figure 3 This is a diagram schematically illustrating a modified example of a foaming apparatus according to the first embodiment.

[0016] Figure 4 This is a schematic diagram illustrating the foaming apparatus of the second embodiment.

[0017] Figure 5 It means that it was used. Figure 4 A flowchart of the foaming method of the foaming device. Detailed Implementation

[0018] (First Implementation)

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following description does not limit the technical scope or the meaning of the terms used in the claims. Furthermore, the dimensions in the drawings are sometimes exaggerated for ease of explanation and differ from the actual dimensions.

[0020] (Foaming materials)

[0021] The gas G is mixed into the liquid resin R (equivalent to a viscous material) by the foaming device 100 and mechanical foaming method of this embodiment, and the gas G is generated by dispersing the bubbles in the liquid of the viscous material.

[0022] For example, applications of foamed material M include airtight electronic components, cylinder head covers for motor vehicles, and sealing materials for waterproofing and dustproofing oil pans. Furthermore, in addition to the above, applications of foamed materials also include vibration-damping applications such as engine compartment panels for motor vehicles, potting of electronic components, and soundproofing, vibration-damping, and heat-insulating materials for housings and enclosures.

[0023] It should be noted that, in this specification, the mixture in which gas G is mixed into liquid resin R, causing bubbles to disperse in the liquid resin R, is called foaming material M, and the state in which gas G foams when foaming material M is sprayed from foaming device 100 into the atmosphere is called a foam (bubble). Furthermore, the liquid resin R before hardening or curing is simply referred to as resin R. It should be noted that the state of "gas mixed into resin" includes both the state in which resin and gas alternate in the piping and the state in which the gas is finely dispersed in the resin.

[0024] Examples of resin R include room temperature curing compositions such as moisture-curing and two-component mixtures, heat-curing compositions, and photocuring compositions such as those cured by ultraviolet light or visible light. Furthermore, resin R can be a thermoplastic resin that melts upon heating and cures upon cooling at room temperature. Resin R includes structures that harden, crosslink, or cure from a fluid state. Examples of resins include silicone resins, modified silicone resins, acrylic resins, polyurethane acrylate resins, epoxy resins, polyurethane resins, polyesters, polypropylene, polyethylene, polycarbonate, synthetic rubber, natural rubber, synthetic resins, and natural resins. Resin R includes a structure called an elastomer.

[0025] As the gas G, nitrogen, carbon dioxide, air, etc. can be preferably used, for example.

[0026] (Mechanical foaming device)

[0027] Figure 1 The overall structure of the foaming device 100 is shown in a general way. The foaming device 100 mixes gas G into resin R to generate foaming material M in the liquid of resin R, and sprays out the foaming material M to foam it and generate a foamed body.

[0028] Reference Figure 1 In a brief description, the foaming apparatus 100 of this embodiment includes a material supply unit 20, a pump unit 30, a mixer 41, an ejection unit 45, a third pressure sensor 46, and a control unit 50. Each part of the apparatus is connected by a piping 10 that forms a flow path for discharging resin R and gas G. It should be noted that in this specification, the side where the material supply unit 20 is located is referred to as the upstream side, and the side where the mixer 41 is located is referred to as the downstream side.

[0029] (Piping)

[0030] Piping 10 allows resin R and gas G to flow. For example... Figure 1 As shown, piping 10 includes a first piping 11, a second piping 12, a third piping 13, a fourth piping 14 (equivalent to the first area), a fifth piping 15, and a sixth piping 16.

[0031] The first piping 11 connects the material supply unit 20 to the first gear pump 31 of the pump unit 30. The second piping 12 connects the first gear pump 31 and the second gear pump 33 at the pump unit 30.

[0032] The third piping 13 connects the gas supply unit 32 to the second piping 12. The fourth piping 14 connects the second gear pump 33 and the third gear pump 34, which constitute the pump unit 30. The fifth piping 15 connects the third gear pump 34 of the pump unit 30 to the mixer 41.

[0033] The sixth pipe 16 connects the mixer 41 to the ejector 45. It should be noted that the diameters of the pipes from the first pipe 11 to the sixth pipe 16 are uniform; however, for example, an on / off valve 35 can be installed on the second pipe 12 near the second gear pump 33. With this configuration, gas can be more easily introduced from the gas supply unit 32, which will be described later. Furthermore, by using a nozzle with a smaller pipe diameter, the foaming ratio can be stabilized.

[0034] The material used to form the piping can be any material that is difficult to deform under pressure within the piping 10, without any particular limitation. For example, metals such as SUS can be preferred.

[0035] (Materials Supply Department)

[0036] The material supply unit 20 supplies resin R to piping 10. For example... Figure 1 As shown, the material supply unit 20 is connected to the first gear pump 31 of the pump unit 30 via the first pipe 11. The material supply unit 20 is composed of replaceable cartridges, tanks, etc., such as tanks for storing resin R and pumps for pressurizing and delivering resin R.

[0037] (Pump section)

[0038] like Figure 1 As shown, the pump unit 30 includes a first gear pump 31, a gas supply unit 32, a second gear pump 33, a third gear pump 34, an on / off valve 35, a first pressure sensor 36, and a second pressure sensor 37.

[0039] The first gear pump 31 is disposed in the middle of the piping 10. Specifically, the first gear pump 31 is disposed downstream of the material supply section 20.

[0040] (Gas Supply Department)

[0041] Gas supply unit 32 supplies gas G to second piping 12 and third piping 13, which are arranged between first gear pump 31 and second gear pump 33 to form piping 10.

[0042] Gas supply unit 32 supplies gas G to piping 10. Gas supply unit 32 pressurizes gas G to a predetermined pressure or atmospheric pressure and supplies it to the second piping 12 and the third piping 13. Gas supply unit 32 includes a gas tank for storing gas G and a gas supply port configured to supply gas G from the gas tank to the second piping 12. Gas supply unit 32 utilizes the suction pressure generated within the second piping 12 during the ejection operation as the suction pressure to attract gas G when supplying gas G to the second piping 12. By adjusting the pressure of the gas G supplied from gas supply unit 32, the foaming ratio of the bubbles can be adjusted.

[0043] The second piping 12 has an intake port configured to allow gas G supplied from the gas supply unit 32 to flow into the piping 10. A portion of the flow path of the second piping 12 is configured such that resin R and gas G are mixed (including a state where resin R and gas G are not mixed).

[0044] The second gear pump 33 is positioned downstream of the first gear pump 31 on the piping 10. The second gear pump 33 is driven to rotate at a higher speed than the first gear pump 31, thereby generating a suction pressure to draw gas into the piping 10 and feeding the resin R containing gas G downstream of the piping 10.

[0045] The third gear pump 34 is positioned downstream of the second gear pump 33 on the piping 10. The third gear pump 34 is driven to rotate at the same speed as the second gear pump 33, thereby feeding the resin R containing gas G further downstream of the piping 10.

[0046] The first gear pump 31, the second gear pump 33, and the third gear pump 34 are equipped with gears and can be constructed from a known gear pump that uses the space between the teeth of each gear to transfer fluid. The first gear pump 31, the second gear pump 33, and the third gear pump 34 are each equipped with a drive gear and a driven gear that rotates driven by the drive gear.

[0047] The drive gear of the first gear pump 31 is driven by the electric motor M1. The drive gear of the second gear pump 33 is driven by the electric motor M2. The drive gear of the second gear pump 33 and the drive gear of the third gear pump 34 are as follows: Figure 1 The axis CL is shown to be coaxial. That is, the drive gear of the third gear pump 34 is driven by the same electric motor M2 as the drive gear of the second gear pump 33.

[0048] The fluid delivery rate of a gear pump is stable at a fixed rate, and the fluid delivery rate can be easily adjusted by changing the rotational speed of the gears. For example, an external gear pump with two gears that are simultaneously driven to rotate through the meshing of their teeth can be used as a gear pump.

[0049] During the ejection action, the second gear pump 33 is driven to rotate at a higher speed than the first gear pump 31. The amount (volume) flowing out of the second pipe 12 through the second gear pump 33 is greater than the amount (volume) flowing into the second pipe 12 through the first gear pump 31. Therefore, within the second pipe 12, a suction pressure is generated corresponding to the volume of the reduced amount of resin R.

[0050] The on / off valve 35 can switch the connection state between the second piping 12 and the gas supply unit 32.

[0051] The on / off valve 35 is located between the gas supply port of the gas supply unit 32 and the second pipe 12, and can open and close the intake port.

[0052] The on / off valve 35 includes a known needle valve. The on / off valve 35 comprises: a needle-shaped valve core that is subjected to force in the closing direction (closing the intake port); a piston connected to the valve core and moving the valve core in the opening direction (opening the intake port); and a cylindrical portion forming a receiving space for accommodating the valve core and the piston. The receiving space of the cylindrical portion is connected to the gas supply port and the second piping 12 via the intake port. It should be noted that the on / off valve 35 may also be constructed as a backflow valve or a ball valve, in addition to the above.

[0053] During the ejection action, such as Figure 1 As shown, the first gear pump 31, the gas supply unit 32, the second gear pump 33 and the third gear pump 34 are driven, and the on / off valve 35 is opened to send the viscous material containing gas to the mixer 41.

[0054] The first pressure sensor 36 can measure (detect) the inter-pump pressure P1 (equivalent to the first pressure) between the first gear pump 31 and the second gear pump 33 in the second piping 12.

[0055] The second pressure sensor 37 can measure (detect) the inter-pump pressure P2 (equivalent to the second pressure) between the second gear pump 33 and the third gear pump 34.

[0056] The mixer 41 is positioned downstream of the third gear pump 34 from the piping 10. It agitates the resin R containing gas G, which is pumped by the third gear pump 34, to generate bubbles. These bubbles disperse in the liquid resin R, forming a foaming material M. The mixer 41 is positioned downstream of the third gear pump 34 from the piping 10 and is located between the pump section 30 and the ejection section 45. Figure 1 As shown, the mixer 41 includes a frame 41a and a rotor 41b.

[0057] like Figure 1 As shown, the frame 41a includes an inlet (not shown), an outlet (not shown), a mixing chamber (not shown), and a frame protrusion 41c. The inlet allows resin R containing gas to flow in from the pipe 10. The outlet allows foaming material M to be discharged to the ejection section 45. The mixing chamber is disposed between the inlet and the outlet, forming a space for mixing the resin R containing gas.

[0058] Multiple frame protrusions 41c are provided on the inner wall surface of the frame forming the mixing chamber. The frame protrusions 41c are alternately spaced from the blades of the rotor 41b along the axial direction of the rotor 41b. The frame protrusions 41c are arranged at predetermined angular intervals along the circumferential direction of the inner wall surface of the mixing chamber, which is formed into a generally cylindrical shape.

[0059] In this embodiment, the axial and circumferential angular intervals of the frame protrusions 41c are both equally spaced. However, the intervals of the frame protrusions 41c do not need to affect the characteristics of the foam, and they can be arranged non-equally in the axial and circumferential directions. Furthermore, the mixer 41 is connected to the cooler (not shown), thereby allowing adjustment of the temperature in the mixer 41.

[0060] The rotor 41b, like the mixing chamber, has a generally cylindrical shape. The rotor 41b is rotatable by an electric motor (not shown). The rotor 41b has the following characteristics: Figure 1 The blades are arranged on the side of the cylindrical shape. The blades of the rotor 41b are also arranged at predetermined intervals along the axial direction of the rotor 41b, just like the frame protrusion 41c.

[0061] Furthermore, multiple blades of rotor 41b are arranged at predetermined angular intervals in the circumferential direction of rotor 41b. In this embodiment, the axial and circumferential spacing of the blades of rotor 41b is equally spaced. However, similar to the frame protrusion 41c, the axial and circumferential spacing of the blades of rotor 41b is not limited to being equally spaced, as long as it does not affect the characteristics of the foam.

[0062] The ejection section 45 includes: a nozzle for ejecting foamed material M generated by dispersing bubbles in a liquid resin R through a mixer 41 as a foam body; a main body having a connecting passage for conveying the foamed material M stirred by the mixer 41 to the nozzle; and an ejection valve that can be opened and closed. The nozzle serves as the ejection outlet for ejecting the foamed material M generated by dispersing bubbles in a liquid resin R through a mixer 41. The ejection valve is preferably a needle valve, and more preferably, the ejection outlet of the nozzle is close to the front end of the needle valve. A third pressure sensor 46 is capable of detecting (measuring) the ejection pressure P3 of the foamed material M just before it is ejected in the connecting passage.

[0063] (Control Department)

[0064] The control unit 50 controls each part of the device by performing an ejection action that ejects the foam material M as a foam body. Furthermore, the control unit 50 controls the ejection action of the foam material M by receiving an ejection signal from the user (ejection signal ON), and can stop the ejection action by no longer receiving an ejection signal (ejection signal OFF).

[0065] (Mechanical foaming method)

[0066] The following is for reference Figure 2 This describes a mechanical foaming method that uses a foaming device 100 to generate foam.

[0067] Figure 2This is a flowchart illustrating a mechanical foaming method according to an embodiment of the present invention.

[0068] In a foaming method, gas G is incorporated into resin R, and the bubbles are dispersed in the liquid of resin R to generate a foamable material M. For example... Figure 2 As shown, the foaming method generally includes spraying actions (S2 to S5). A detailed description follows.

[0069] When the user turns on the power to the foaming device 100, the control unit 50 activates the mixer 41 in a state of operational readiness (S1). The mixer 41 can be in a state of constant operation, at least in the operational readiness state. Furthermore, the control unit 50 controls the supply of resin R from the material supply unit 20 to the piping 10.

[0070] Next, the control unit 50 receives a control signal (ejection signal ON, S2) to start the ejection action of the foam material M by the user's operation.

[0071] Next, the control unit 50 drives the first gear pump 31 and the second gear pump 33 to rotate at a higher speed than the first gear pump 31. Furthermore, the control unit 50 drives the third gear pump 34 to rotate at the same speed as the second gear pump 33, utilizing a coaxial configuration.

[0072] As a result, the amount (volume) of resin R flowing out of the second pipe 12 via the second gear pump 33 is greater than the amount of resin R flowing into the second pipe 12 via the first gear pump 31. Therefore, a suction pressure is generated within the second pipe 12 corresponding to the volume of the reduced amount of resin R.

[0073] Next, the control unit 50 opens the on / off valve 35 to connect the second piping 12 to the gas supply unit 32. At this time, gas G is drawn from the gas supply unit 32 by the suction pressure in the second piping 12, and the pressurized or atmospheric pressure gas G is mixed into the second piping 12 through the third piping 13 after being pressure-transmitted by the gas supply unit 32.

[0074] It should be noted that the on / off valve 35 is preferably opened after a predetermined time, for example, 0.1 to 0.5 seconds, has elapsed since the first gear pump 31 and the second gear pump 33 began to rotate. This allows the second piping 12 to be connected to the gas supply unit 32 while maintaining suction pressure within the second piping 12, thus preventing backflow of resin R into the gas supply unit 32.

[0075] In addition, after a specified time, the opening and closing valve 35 is opened, and the pressure in the flow path between the first gear pump 31 and the second gear pump 33 decreases compared with the pressure of the supplied gas, so that the gas can be supplied stably.

[0076] The gas G introduced into the second gear pump 33, together with the resin R, is sent to the mixer 41 by the third gear pump 34. The resin R containing gas, pressurized from the third gear pump 34, flows into the mixing chamber from the inlet of the mixer 41. The third gear pump 34 is controlled to be coaxial with the second gear pump 33, thereby feeding the resin R containing gas into the mixer 41.

[0077] When the rotor 41b is rotated by the electric motor, the blades of the rotor 41b rotate around the axis of the rotor 41b, and together with the frame protrusion 41c, agitate the resin R containing gas in the mixing chamber. As a result, the gas G in the resin R is dispersed in a finely dispersed manner due to shear force, generating a foaming material M. The rotational speed of the rotor 41b can be set, for example, from 1 to 100 rpm.

[0078] Next, the foamed material M generated by the mixer 41 is discharged from the outlet of the mixer 41 to the communication path provided in the ejection section 45. As a result, the foamed material M is ejected into the atmosphere from the nozzle via the communication path (S3). The gas G of the foamed material M ejected into the atmosphere is released from the pressurized state and hardens or solidifies in an expanded and foamed state to form a foam.

[0079] It should be noted that, for ease of explanation, the explanations are presented in chronological order. Figure 2 The actions of S3 are all possible, but in reality, there are also situations where the actions are performed roughly simultaneously.

[0080] The control unit 50 controls the spraying action to stop because the user's operation no longer receives a signal indicating the spraying action of the foaming material M (spraying signal OFF) (S4). Accepting this, the control unit 50 controls the first gear pump 31, the second gear pump 33, and the third gear pump 34 to stop. Then, the control unit 50 controls the operation by closing the on / off valve 35 and the spraying valve of the spraying unit 45 (S5). It should be noted that in the case of continuous spraying action, S2 can be returned after S5 to perform the actions of S2 to S5 a predetermined number of times.

[0081] As described above, the foaming apparatus 100 of this embodiment sprays out a foaming material M that mixes gas G into resin R and disperses bubbles in the liquid of resin R. The foaming apparatus 100 includes a piping 10, a material supply unit 20, a gas supply unit 32, a first gear pump 31, a second gear pump 33, a third gear pump 34, a mixer 41, an ejection unit 45, and a control unit 50.

[0082] Pipeline 10 allows resin R and gas G to flow. Material supply unit 20 supplies resin R to pipeline 10. Gas supply unit 32 supplies gas G to pipeline 10. First gear pump 31 is located midway through pipeline 10.

[0083] The second gear pump 33 is positioned downstream of the first gear pump 31 on the piping 10. The second gear pump 33 is driven to rotate at a higher speed than the first gear pump 31, thereby causing gas G to flow into the piping 10 and feeding resin R containing gas G downstream of the piping 10. The third gear pump 34 is positioned downstream of the second gear pump 33 on the piping 10, and is driven to rotate at the same speed as the second gear pump 33, thereby feeding resin R containing gas G further downstream of the piping 10.

[0084] The mixer 41 is positioned downstream of the third gear pump 34 from the piping 10, dispersing air bubbles in the resin R within the liquid resin R. The ejector 45 ejects the foaming material M, in which the air bubbles are dispersed in the liquid resin R by the mixer 41. The control unit 50 controls the ejection of the foaming material M.

[0085] This configuration eliminates or reduces the load on the second gear pump 33. Consequently, the mixing ratio of resin R to gas G can be stabilized, and the foaming ratio of the foaming material M ejected from the ejection section 45 can be stabilized. Furthermore, the foaming device 100 includes a third gear pump 34 in addition to the first gear pump 31 and the second gear pump 33, thus ensuring stable ejection during initial movement even without adjustment.

[0086] Furthermore, the drive gear of the third gear pump 34 is driven by the same electric motor M2 as the drive gear of the second gear pump 33. This ensures that the differential pressure between the second gear pump 33 and the third gear pump 34 is either not generated or is approximately zero. Therefore, the load on the second gear pump 33 can be eliminated or reduced, contributing to the achievement of a stable mixing ratio of the resin R and gas G ejected from the ejection section 45.

[0087] Furthermore, the foaming method of this embodiment involves mixing gas G into resin R and dispersing bubbles in the liquid of resin R to generate a foamable material M. In this foaming method, among the first gear pump 31, the second gear pump 33, and the third gear pump 34 arranged sequentially from the upstream side to the downstream side in the piping 10 that circulates resin R and gas G, the second gear pump 33 is driven to rotate at a higher speed than the first gear pump 31.

[0088] Furthermore, a suction pressure is generated between the first gear pump 31 and the second gear pump 33 within the piping 10, causing gas G to be mixed in. Additionally, the third gear pump 34 is driven to rotate at the same speed as the second gear pump 33, supplying resin R containing gas G to a mixer 41 located downstream of the third gear pump 34 within the piping 10, which disperses air bubbles in the liquid resin R.

[0089] This eliminates or reduces the load on the second gear pump 33, stabilizes the mixing ratio of resin R and gas G ejected from the ejection section 45, and stabilizes the foaming ratio of the foaming material M.

[0090] (A variation of the first embodiment)

[0091] Figure 3 This diagram schematically illustrates a modified example of the foaming apparatus 100a according to the first embodiment. The foaming apparatus 100a differs from the first embodiment in that the drive gear of the third gear pump 34a is driven by a motor M3, which is different from the drive gear of the second gear pump 33. Furthermore, the control unit 50a constituting the foaming apparatus 100a differs from the first embodiment in that it controls each part of the apparatus including the third gear pump 34a.

[0092] In this modified example, the second gear pump 33 and the third gear pump 34a are not operated by the same electric motor M2; the third gear pump 34a is operated by a different electric motor M3 than the electric motor M2. The control unit 50a controls each part of the device in the same manner as in the first embodiment, with the second gear pump 33 and the third gear pump 34a operating in the same way. Other aspects are the same as in the first embodiment, and therefore, descriptions are omitted.

[0093] (Second Implementation)

[0094] Figure 4 The foaming apparatus 100b of the second embodiment of the present invention is shown schematically. Figure 5 This is a flowchart illustrating a foaming method using the foaming apparatus 100b of the second embodiment. In the second embodiment, the point at which the circulation path is provided for the foaming apparatus 100b of the first embodiment differs from that of the foaming apparatus 100.

[0095] like Figure 4 As shown, the foaming device 100b includes a piping 10b, a material supply unit 20, a pump unit 30b, a mixer 41, an ejection unit 45, a third pressure sensor 46, circulation valves 47 and 48, and a control unit 50b.

[0096] (Piping)

[0097] Piping 10b includes a first piping 11, a second piping 12, a third piping 13, a fourth piping 14, a fifth piping 15, a sixth piping 16, and a seventh piping 17. The first piping 11 to the sixth piping 16 have the same structure as the piping 10 of the foaming apparatus 100 in the first embodiment, so the description is omitted.

[0098] The seventh pipe 17 connects the downstream region of the ejection section 45 to the fourth pipe 14, which is located in the first region between the second gear pump 33 and the third gear pump 34a. The portion of the fourth pipe 14 downstream of the connection point with the seventh pipe 17, the fifth pipe 15, the sixth pipe 16, and the seventh pipe 17, in this specification, correspond to the circulation path connecting the region between the second gear pump 33 and the third gear pump 34a.

[0099] (Materials Supply Department)

[0100] The material supply unit 20 is the same as the foaming device 100 in the first embodiment, so its description is omitted.

[0101] (Pump section)

[0102] like Figure 5 As shown, the pump unit 30b includes a first gear pump 31, a gas supply unit 32, a second gear pump 33, a third gear pump 34a, an on / off valve 35, a first pressure sensor 36, a second pressure sensor 37, and a switching valve 38 (equivalent to a third valve).

[0103] The first gear pump 31, gas supply unit 32, second gear pump 33, on / off valve 35, first pressure sensor 36, and second pressure sensor 37 have the same structure as the foaming device 100 of the first embodiment, and therefore their description is omitted. The third gear pump 34a is operated by the electric motor M3 in the same way as the foaming device 100a of the modified example of the first embodiment.

[0104] The switching valve 38 is configured on the fourth pipe 14, which corresponds to the first region between the second gear pump 33 and the third gear pump 34, and can open and close the flow path between the second gear pump 33 and the third gear pump 34a.

[0105] The switching valve 38 is not particularly limited and can be composed of a full-bore ball valve or the like, which has no flow resistance (or low flow resistance).

[0106] (Mixer, ejector, third pressure sensor, circulation valve)

[0107] The mixer 41, the ejector 45, and the third pressure sensor 46 have the same structure as the foaming device 100 of the first embodiment, so their description is omitted. In this specification, the circulation valve 47 corresponds to the first valve, and the circulation valve 48 corresponds to the second valve.

[0108] The circulation valve 47 is disposed in the seventh pipe 17 that constitutes the circulation path. The circulation valve 48 is disposed in the seventh pipe 17 that constitutes the circulation path at a position downstream of the circulation valve 47.

[0109] (Control Department)

[0110] The control unit 50b controls each part of the device by switching between the spraying operation and the circulation operation in the piping 10b, which includes the circulation path. During the spraying operation, the control unit 50b closes the circulation valves 47 and 48 and opens the switching valve 38, and feeds the resin R containing gas G into the mixer 41 by driving the first gear pump 31, the second gear pump 33 and the third gear pump 34a.

[0111] During cyclic operation, the control unit 50b closes the switching valve 38 and opens the circulation valves 47 and 48 to control each part of the device by driving the first gear pump 31, the second gear pump 33, and the third gear pump 34a. As a result, the resin R containing gas G circulates in the circulation path and the mixer 41 to maintain the foaming state of the foaming material M.

[0112] (Foaming method)

[0113] Next, a foaming method using the foaming apparatus 100b of this embodiment will be described.

[0114] When the user turns on the power to the foaming device 100b, the control unit 50b activates the mixer 41 in a ready-to-operate state (S11). Furthermore, the control unit 50b controls the supply of resin R from the material supply unit 20 to the piping 10b. Next, the control unit 50b controls the operation by closing the switching valve 38 and opening the circulation valves 47 and 48 (S12).

[0115] Next, the control unit 50b drives the third gear pump 34a (S13). As a result, the foaming material M in the circulation path circulates within the circulation path.

[0116] When the control unit 50b receives a spray signal from the user's action (spray signal ON, S14), the control unit 50b stops the third gear pump 34a and controls it by closing the circulation valves 47 and 48 and opening the switching valve 38 (S15).

[0117] Next, the control unit 50b drives the first gear pump 31 and the second gear pump 33 to rotate at a higher speed than the first gear pump 31. Furthermore, the control unit 50b drives the third gear pump 34a to rotate at the same speed as the second gear pump 33.

[0118] Then, the control unit 50b controls the process by opening the on / off valve 35 and opening the spray valve of the spray unit 45 (S16). As in the first embodiment, resin R containing gas G is fed into the mixer 41, generating a foaming material M in which gas G is dispersedly mixed into resin M1 and sprayed out from the nozzle of the spray unit 45.

[0119] When the control unit 50b no longer receives the ejection signal due to user operation (ejection signal off, S17), the control unit 50b controls the first gear pump 31, the second gear pump 33, and the third gear pump 34a to stop. Furthermore, the control unit 50b controls the operation by closing the on / off valve 35 and the ejection valve of the ejection unit 45 (S18). It should be noted that in the case of continuous ejection operations, S18 can be followed by S12, and the operations of S12 to S18 can be performed a predetermined number of times.

[0120] As described above, in the foaming apparatus 100b of this embodiment, the piping 10b has a circulation path connecting the downstream area of ​​the spray section 45 to a first area, the first area being the area between the second gear pump 33 and the third gear pump 34a. The foaming apparatus 100 includes circulation valves 47 and 48, and a switching valve 38.

[0121] Circulation valve 47 is disposed in the seventh pipe 17 in the circulation path. Circulation valve 48 is disposed in the circulation path downstream of circulation valve 47. Switching valve 38 is disposed in the fourth pipe 14, which is the first area between the second gear pump 33 and the third gear pump 34a. During the spraying operation, control unit 50b closes circulation valves 47 and 48, opens switching valve 38, and drives the third gear pump 34a to rotate, thus feeding foaming material M into mixer 41.

[0122] In addition, during the cycle operation, the control unit 50b opens the circulation valves 47 and 48 and closes the switching valve 38, and drives the third gear pump 34a to rotate, so as to circulate the foaming material M in the circulation path and the mixer 41, thereby maintaining the foaming state of the foaming material M.

[0123] Therefore, the foaming material M can maintain or easily maintain a homogeneous dispersion in the circulation path constituting the piping 10b. Moreover, it can prevent or suppress the decrease in foaming ratio that would occur when the spraying of the foaming material M stops.

[0124] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made in the claims. The above description illustrates the case where control units 50, 50a, and 50b receive the ejection signal through user operation, but is not limited thereto. In addition to the above, the control units may also receive the ejection signal from other higher-level devices.

[0125] This application is based on Japanese Patent Application No. 2020-201002, filed on December 3, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0126] Symbol Explanation

[0127] 100, 100a, and 100b foaming devices

[0128] 10, 10b piping (flow path),

[0129] 14. Fourth piping (circulation path, first zone)

[0130] 15. Fifth piping (circulation path)

[0131] 16. Sixth piping (circulation path)

[0132] 17. Seventh piping (circulation path)

[0133] 20. Materials Supply Department

[0134] 32. Gas Supply Department

[0135] 31 First gear pump,

[0136] 33 Second gear pump,

[0137] 34, 34a Third gear pump,

[0138] 38. Switching valve (third valve)

[0139] 41 Mixer

[0140] 45. Ejector section.

[0141] 47. Circulation valve (first valve)

[0142] 48. Circulation valve (second valve)

[0143] Control units for models 50, 50a, and 50b.

[0144] M-type foamed material,

[0145] R resin (adhesive material),

[0146] G gas,

[0147] P1 Pump Interval Pressure (First Pressure)

[0148] P2 Pump Interval Pressure (Second Pressure).

Claims

1. A foaming apparatus comprising: mixing gas into a viscous material and spraying out a foaming material that disperses bubbles in a liquid of the viscous material; the foaming apparatus comprising: A flow path that allows the viscous material and the gas to circulate; A material supply unit that supplies the viscous material to the flow path; A gas supply unit that supplies the gas to the flow path; A first gear pump is disposed in the middle of the flow path; The second gear pump, which is positioned downstream of the first gear pump in the flow path, is driven to rotate at a higher speed than the first gear pump, thereby causing the gas to flow into the flow path and feeding the viscous material containing the gas downstream of the flow path. A third gear pump, which is positioned downstream of the second gear pump in the flow path, is driven to rotate at the same speed as the second gear pump, thereby feeding the viscous material containing the gas further downstream in the flow path. A mixer, positioned downstream of the flow path from the third gear pump, disperses air bubbles in the viscous material within the liquid of the viscous material. The ejector section ejects the foaming material, which has been dispersed in the viscous liquid by the mixer through bubbles; and The control unit controls the spraying action of the foaming material. The drive gear of the third gear pump is driven by the same electric motor as the drive gear of the second gear pump. The second gear pump and the third gear pump are connected by piping.

2. The foaming device according to claim 1, wherein, The flow path has a circulation path connecting the downstream region of the ejector portion with a first region, the first region being the region between the second gear pump and the third gear pump. The foaming device includes a first valve disposed in the circulation path, a second valve disposed downstream of the first valve in the circulation path, and a third valve disposed in the first region. During the ejection action, the control unit closes the first and second valves, opens the third valve, and drives the third gear pump to rotate, thereby feeding the viscous material containing the gas into the mixer. During the circulation operation, the control unit closes the third valve, opens the first valve and the second valve, and drives the third gear pump to rotate, thereby circulating the viscous material containing the gas in the circulation path and the mixer to maintain the foaming state of the foaming material.

3. The foaming device according to claim 1 or 2, wherein, The control unit controls each part of the device and controls the ejection action.

4. A foaming method comprising mixing gas into a viscous material to generate a foaming material in which bubbles are dispersed in a liquid of the viscous material, wherein, In a flow path through which the viscous material and the gas circulate, a first gear pump, a second gear pump, and a third gear pump are sequentially arranged from upstream to downstream. The second gear pump is driven to rotate at a higher speed than the first gear pump, creating a suction pressure between the first and second gear pumps within the flow path to mix in the gas. The third gear pump is driven to rotate at the same speed as the second gear pump, feeding the viscous material containing the gas into a mixer. The mixer is positioned downstream of the third gear pump within the flow path, dispersing air bubbles from the viscous material within the liquid form of the viscous material. The drive gear of the third gear pump is driven by the same electric motor as the drive gear of the second gear pump. The second gear pump and the third gear pump are connected by piping.

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