JP2009084480A - Apparatus and method of manufacturing polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing polyurethane foam which is capable of preventing the vaporization of carbon dioxide during feeding. <P>SOLUTION: The apparatus for manufacturing the polyurethane foam includes supply pumps for respectively delivering an A liquid and a B liquid so as to become prescribed discharge pressure, supply pipes for respectively supplying the A liquid and the B liquid delivered by the feed pumps while keeping respective discharge pressure, a feed pipe for feeding liquefied carbon dioxide as a foaming agent to a supply pipe from a liquefied carbon dioxide container having inside pressure higher than the discharge pressure, a discharge apparatus for mixing the liquefied carbon dioxide with one of the A liquid and the B liquid and discharging the mixture, an on-off valve disposed in the middle of the supply pipe for switching the feeding and the stoppage of the liquefied carbon dioxide fed through the feed pipe, and a valve control means for switching the on-off of the on-off valve linked with the supply pump to control the flow rate of the liquefied carbon dioxide. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a polyurethane foam manufacturing apparatus and a manufacturing method thereof, and relates to a polyurethane foam manufacturing apparatus suitable for foaming polyurethane foam performed using liquid (supercritical, subcritical, or liquid) carbon dioxide as a foaming agent, and It relates to the manufacturing method.

  Conventionally, polyurethane foam has been widely used as a heat insulating board, a heat insulating material by spraying, a filling agent, and the like. Such a polyurethane foam usually uses a raw material liquid containing a polyisocyanate component, an active hydrogen group-containing compound component, and a foaming agent. It is manufactured by being discharged from and reacting and solidifying while the foaming limited amount of foaming is foamed.

  However, in recent years, many foaming agents such as Freon are being regulated as foaming agents for polyurethane foam due to problems such as ozone layer destruction, and methods using carbon dioxide as the foaming agent are being studied. When carbon dioxide is used as a blowing agent, it is necessary to use liquefied carbon dioxide (hereinafter referred to as liquefied carbon dioxide) and supply a predetermined amount thereof, but liquefied carbon dioxide has a critical point of about 31 ° C., about It is 7 MPa, and tends to be a gas at room temperature. For this reason, when liquefied carbon dioxide is to be metered and pumped from a carbon dioxide storage container such as a cylinder by a pump, there is a problem in that a predetermined amount cannot be pumped because gaseous carbon dioxide is mixed into the liquefied carbon dioxide. In particular, since the pressure tends to decrease on the suction side of the pump, there is a problem that carbon dioxide, which has become even more gaseous, is mixed into the liquefied carbon dioxide and a predetermined amount cannot be pumped.

  For this reason, various ideas for supplying a predetermined amount of liquid carbon dioxide without vaporization have been proposed.

For example, in Patent Document 1, a pressurized gas container is provided, and a pressurized gas is supplied from the pressurized gas container to the liquefied carbon dioxide container and pressurized to hold the liquefied carbon dioxide as a liquid. Patent Document 2 discloses a technique for keeping the temperature of liquefied carbon dioxide low and preventing vaporization of liquefied carbon dioxide introduced into the first liquefied carbon dioxide metering pump and the second liquefied carbon dioxide metering pump. ing. Patent Document 3 discloses that a chiller that adjusts the temperature of the refrigerant includes a refrigerant and a heat transfer tube that cools the refrigerant, and a liquefied carbon dioxide transfer channel is provided in the chiller. .
JP 2006-192720 A Japanese Patent Laid-Open No. 2005-200484 JP 2006-29895 A

  However, all of the urethane foam manufacturing apparatuses disclosed in the above patent documents measure and supply the amount of carbon dioxide supplied using a carbon dioxide metering pump, and a pump for supplying carbon dioxide is essential. And That is, the problem of vaporization of liquefied carbon dioxide is caused by the use of a pump for measuring carbon dioxide. As long as the pump is used, the problem of vaporization of liquefied carbon dioxide occurs. For this reason, in order to solve the problem as much as possible, in the urethane foam manufacturing apparatus disclosed in each of the above patent documents, a heat exchanger such as a chiller and a distribution pipe should be insulated to keep the temperature of liquefied carbon dioxide low. Alternatively, the pressure is increased using a pressurized gas container to prevent vaporization.

  However, even if the liquefied state can be maintained in the vicinity of the liquefied carbon dioxide container, as long as the carbon dioxide is metered using the pump, the pressure tends to decrease during the suction process on the suction side of the pump, and the liquefied carbon dioxide is vaporized. It is not a drastic solution to the above problem of being easily converted. In addition, since the number of members such as a pressurized container and a heat exchanger increases, the apparatus becomes large and complicated.

  Therefore, in view of the above problems, the technical problem to be solved by the present invention is to solve the problem of measuring an appropriate amount of carbon dioxide with a pump and to solve the problem of vaporization of carbon dioxide by using the pump. An object of the present invention is to provide a polyurethane foam production apparatus and a production method thereof that can be eliminated.

  In order to solve the above technical problem, the present invention provides a polyurethane foam production apparatus having the following constitution and a production method therefor.

According to the first aspect of the present invention, the liquid A mainly composed of polyisocyanate, the liquid B mainly composed of polyol, and liquefied carbon dioxide as a blowing agent supplied from the liquefied carbon dioxide container are mixed. When manufacturing polyurethane foam,
A supply pump for sending out the A liquid and the B liquid so as to have a predetermined discharge pressure;
A supply pipe for feeding while maintaining the A liquid and B liquid respectively sent out by the supply pump;
A feed pipe for feeding liquefied carbon dioxide as a blowing agent supplied from a liquefied carbon dioxide container whose inside is higher than the discharge pressure to the supply pipe;
A discharge device for mixing and discharging the liquefied carbon dioxide into at least one of the liquid A and the liquid B;
An on-off valve that is provided in the middle of the feed pipe and switches between feeding and stopping of liquefied carbon dioxide fed through the feed pipe;
Valve control means for switching opening and closing of the on-off valve in conjunction with the supply pump in order to control the flow rate of the liquefied carbon dioxide;
An apparatus for producing polyurethane foam is provided.

  According to a second aspect of the present invention, there is provided the polyurethane foam manufacturing apparatus according to the first aspect, wherein the opening and closing of the on-off valve is switched so that the on-off valve is opened when the supply pump is driven.

  According to a third aspect of the present invention, the valve control means changes the open / close valve from a closed state to an open state in conjunction with the start of driving of the supply pump, and after a predetermined time has elapsed after the supply pump has stopped driving. The polyurethane foam manufacturing apparatus according to the first aspect, wherein the on-off valve is changed from an open state to a closed state.

According to the fourth aspect of the present invention, the supply pump sends out the liquid A and the liquid B by moving the piston,
The said valve control means provides the polyurethane foam manufacturing apparatus as described in a 1st aspect which switches opening and closing of the said on-off valve in response to the movement of the said piston.

  According to a fifth aspect of the present invention, the valve control means includes a supply pump drive detection unit that detects a drive state of the supply pump according to whether the piston physically contacts the piston by movement of the piston, The polyurethane foam manufacturing apparatus according to the fourth aspect, wherein the on / off valve is switched between open and closed in conjunction with the drive state of the supply pump detected by the supply pump drive detection unit.

According to a sixth aspect of the present invention, the valve control means includes
When the supply pump drive detection unit physically contacts the piston when the on-off valve is closed, the open / close valve is changed from the closed state to the open state, and the supply pump drive detection unit physically contacts the piston. When the piston is physically contacted again before a predetermined time elapses, the on-off valve is maintained in an open state, and after the supply pump drive detection unit physically contacts the piston, the piston is again turned on before the predetermined time elapses. The polyurethane foam manufacturing apparatus according to the fifth aspect is provided, wherein the on-off valve is changed from the open state to the closed state when there is no physical contact.

According to a seventh aspect of the present invention, the valve control means is
A supply pump drive detector for detecting the start of driving of the supply pump and transmitting a drive detection signal;
A control unit having a signal detection unit for detecting the drive detection signal, a timer unit for counting a predetermined time, and a trigger signal transmission unit for transmitting a trigger signal for opening and closing the on-off valve;
The controller is
When the signal detection unit detects the drive detection signal, the timer unit starts counting, and the trigger signal transmission unit outputs a trigger signal that causes the on-off valve to be opened from a closed state, and the timer unit When the signal detection unit detects a new drive detection signal before completing the count, the count is reset and the count is started again, and when the timer unit completes the count, the trigger signal The transmitter controls to output a trigger signal for closing the on-off valve;
A polyurethane foam production apparatus according to the first aspect is provided.

According to the eighth aspect of the present invention, the supply pump sends out the A liquid and the B liquid by moving the piston,
The supply pump drive detection unit includes a switch that transmits the drive detection signal when the piston physically contacts the piston by movement of the piston.
A polyurethane foam production apparatus according to the seventh aspect is provided.

According to the ninth aspect of the present invention, it further comprises a throttle mechanism capable of adjusting the flow rate of the liquefied carbon dioxide, and an outside air temperature detecting unit for detecting the outside air temperature,
The control unit automatically controls the aperture amount of the aperture mechanism according to the outside air temperature information detected by the outside air temperature detection unit.
A polyurethane foam production apparatus according to any one of the first to eighth aspects is provided.

  According to a tenth aspect of the present invention, the pressure in the liquefied carbon dioxide container is 5 MPa to 8 MPa, and the discharge pressure is 4 MPa to 7 MPa. The polyurethane foam according to any one of the first to ninth aspects. Providing manufacturing equipment.

According to the eleventh aspect of the present invention, a liquid A mainly composed of polyisocyanate, a liquid B mainly composed of a polyol, and liquefied carbon dioxide as a blowing agent supplied from a liquefied carbon dioxide container are mixed. When manufacturing polyurethane foam,
A supply pump for sending out the A liquid and the B liquid so as to have a predetermined discharge pressure;
A supply pipe for feeding the liquid A and liquid B respectively sent out by the supply pump while maintaining a pre-discharge pressure;
A feed pipe for feeding liquefied carbon dioxide as a foaming agent supplied from a liquefied carbon dioxide container having a first pressure higher than the discharge pressure to the supply pipe;
A discharge device for mixing and discharging the liquefied carbon dioxide into at least one of the liquid A and the liquid B;
An on-off valve that is provided in the middle of the feed pipe and switches between feeding and stopping of liquefied carbon dioxide fed through the feed pipe;
Using a polyurethane foam production apparatus comprising: a method of producing a polyurethane foam by reacting liquid A and liquid B discharged from the discharge device,
In order to control the flow rate of the liquefied carbon dioxide, there is provided a polyurethane foam manufacturing method characterized by switching the opening / closing of the on-off valve in conjunction with the supply pump.

  Here, in general, carbon dioxide in a supercritical state is not in a liquid state, but in the present invention, liquefied carbon dioxide includes carbon dioxide in a supercritical state, a subcritical state, and a liquid state. Subcritical carbon dioxide is liquid carbon dioxide whose pressure is higher than the critical pressure of carbon dioxide and whose temperature is lower than the critical temperature, or whose pressure is lower than the critical pressure of carbon dioxide and whose temperature is critical. Carbon dioxide in a liquid state at a temperature or higher and a state in which both the temperature and pressure are less than the critical point but close to this, specifically, carbon dioxide having a temperature of 20 ° C. or higher and a pressure of 5 MPa or higher. .

  According to the first aspect of the present invention, the on-off valve is opened and closed in conjunction with the supply pump that supplies the A liquid and the B liquid to the discharge device, and the pressure difference between the pressure in the liquefied carbon dioxide container and the discharge pressure is utilized. In this way, liquefied carbon dioxide is fed. Thereby, feeding of liquefied carbon dioxide can be performed without using a pump, and vaporization of carbon dioxide accompanying use of the pump can be prevented.

  Further, according to the seventh aspect of the present invention, after detecting the start of driving the supply pump, the on-off valve is opened until a predetermined time elapses, and when the drive of the supply pump is newly detected within the predetermined time, The count for a predetermined time is reset and the count is started again. Thereby, even if the drive time of the supply pump is irregular, the on-off valve can be opened for an appropriate time according to the drive time. Therefore, the flow rate of liquefied carbon dioxide can be adjusted with high accuracy, the discharge pressure can be stabilized, and the need to strictly measure carbon dioxide using a pump can be eliminated.

  Hereinafter, a polyurethane foam manufacturing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a diagram schematically showing a configuration of a polyurethane foam manufacturing apparatus according to a first embodiment of the present invention. The polyurethane foam manufacturing apparatus 1 according to the first embodiment shown in FIG. 1 shows a case where liquefied carbon dioxide is supplied to the polyol component, and the liquefied carbon dioxide 100 stored in the liquefied carbon dioxide container 20. This is a device that transports the component liquid mixed with the isocyanate component (see FIG. 2) and the isocyanate component while heating them using the warmer 3 and the hose heater 4, and mixes and discharges them in the spray gun 5.

  As shown in FIG. 1, the polyurethane foam manufacturing apparatus 1 stores a liquefied carbon dioxide container 20, a polyol component storage container 30 storing B liquid mainly containing polyol, and A liquid mainly containing polyisocyanate. A primary piping L11 and a secondary piping L12 that constitute an example of a feeding piping that conveys the liquefied carbon dioxide 100 (the upstream side from the check valve 29 as will be described later). L12a, the downstream side is L12b), a B liquid pipe L13 that is an example of a supply pipe that transports B liquid, and an A liquid pipe L14 that is an example of a supply pipe that transports A liquid. It has the structure connected to.

  The starting end of the primary pipe L <b> 11 that conveys the liquefied carbon dioxide 100 is connected to the connector 22 of the liquefied carbon dioxide container 20. A filter 23, a blow valve 24, and a first pressure gauge 25 are provided in the middle of the primary pipe L11. The terminal end of the primary pipe L11 is connected to the secondary pipe L12 via an on-off valve 26 and a needle valve 27 which is an example of a throttle mechanism. The secondary pipe L12 is provided with a second pressure gauge 28 and a check valve 29, and is connected to a mixer 32 provided in the B liquid pipe L13.

  The B liquid pipe L <b> 13 includes a B liquid supply pump 31 and a mixer 32, and communicates with the spray gun 5 of the discharge device 2. The A liquid pipe L <b> 14 includes the A liquid supply pump 41 and communicates with the spray gun 5 of the discharge device 2. The spray gun 5 mixes the A liquid fed by the A liquid piping L14 and the B liquid piping L13 with the B liquid mixed with the liquefied carbon dioxide 100 by the mixer 32, and discharges it from the discharge port. The A liquid pipe L14 and the B liquid pipe L13 are provided with the heater 3 and the hose heater 4 as described above. Thereby, the reaction condition (resin reaction) can be stabilized by heating the liquid to be fed and keeping the temperature constant, and the reactivity at the time of discharge from the spray gun 5 can be increased. . That is, by heating the liquid flowing through the A liquid pipe L14 and the B liquid pipe L13 by the heater 3 and the hose heater 4, carbon dioxide is easily dispersed in the A liquid and / or the B liquid, and the polyurethane foam Foaming can be promoted. As shown in FIG. 8, the warmer 3 is composed of two warmers 3a and 3b, and is configured to independently heat the liquid flowing in the liquid A pipe L14 and the liquid B pipe L13. May be. Similarly, as shown in FIG. 8, the hose heater 4 is composed of two hose heaters 4a and 4b, and is configured to independently heat the liquid flowing in the liquid A pipe L14 and the liquid B pipe L13. May be.

  In the example of FIG. 1, the liquefied carbon dioxide 100 is configured to be mixed with the B liquid, but may be configured to be mixed with both the A liquid and the B liquid. In this case, a mixer 42 (see FIG. 8) is provided in the A liquid pipe L14, the terminal end side of the secondary pipe L12 is branched, and the branched terminals are connected to the mixers 32 and 42, respectively. You can do it. Further, the liquefied oxygen dioxide 100 may be configured to be mixed with the A liquid instead of the B liquid. In this case, the end of the secondary pipe L12 may be connected to the mixer 42 (see FIG. 8) provided in the A liquid pipe L14.

  As shown in FIG. 2, the liquefied carbon dioxide container 20 is a container with a siphon tube in which a siphon tube L20 is provided. In addition, a container is not specifically limited, The thing provided generally may be used. For example, a container such as a small gas cylinder that has high pressure resistance and is not thermally insulated may be used as the liquefied carbon dioxide container 20.

  The liquefied carbon dioxide container 20 is provided with a heating member 21 for heating the container. The heating member 21 is for heating the liquefied carbon dioxide 100 stored in the liquefied carbon dioxide container 20 to increase the pressure inside the container. Specific examples of the heating member 21 include a method of immersing a container in an electric heater, a steam heater, or a hot water tank.

  The heating member 21 heats the liquefied carbon dioxide 100 so that the internal pressure of the liquefied carbon dioxide container 20 is about 5 to 8 MPa, preferably 7 to 8 MPa. Hereinafter, the internal pressure set to the said range by heating the liquefied carbon dioxide container 20 is described as a 1st pressure. In addition, although the gas cylinder marketed normally changes with temperature conditions, since an internal pressure is about 3-7 Mpa and does not satisfy the said 1st pressure in winter, it heats. The heating temperature is 40 ° C. or lower. The heating member 21 is provided for the purpose of setting the inside of the liquefied carbon dioxide container 20 to the first pressure. For this reason, for example, when the outside air temperature at midsummer is extremely high and the pressure in the container exceeds the range of the first pressure, cooling to cool the liquefied carbon dioxide container 20 so as to adjust to the range of the first pressure. A member may be used instead of the heating member 21.

  The reason why the first pressure is set to the above value is to prevent the liquefied carbon dioxide 100 in the liquefied carbon dioxide container 20 and the primary pipe L11 from being vaporized. For this reason, if the temperature condition is such that the liquefied carbon dioxide 100 does not vaporize, the first pressure can be set near the critical pressure (7.382 MPa (abs)) or higher than the critical pressure.

  The primary pipe L11 is made of, for example, a 6φ stainless steel pipe, and feeds the liquefied carbon dioxide 100 supplied from the liquefied carbon dioxide container 20 while maintaining the first pressure. The filter 23 provided in the primary pipe L11 is for removing foreign matter in the primary pipe L11, and foreign matter is added to the needle valve 27 and the like for narrowing the feeding flow path of the liquefied carbon dioxide 100. Prevent clogging. The first pressure gauge 25 is provided so as to detect the pressure in the primary pipe L11, that is, the internal pressure of the liquefied carbon dioxide container 20. Based on the detection value of the first pressure gauge 25, the heating operation of the heating member 21 is controlled.

  The on-off valve 26 is a member that connects the primary pipe L11 and the secondary pipe L12, and is electrically controlled to open and close by the control unit 10 described in detail later. The on-off valve 26 has a pressure adjusting function of a primary pressure system on the upstream side and a secondary pressure system on the downstream side thereof. That is, the pressure in the primary pipe L11 and the secondary pipe L12 connected to both ends of the on-off valve 26 is different.

  The needle valve 27 provided in the secondary pipe L12 adjusts the flow amount of the liquefied carbon dioxide 100 sent from the primary pipe L11 to the secondary pipe L12 by adjusting the amount of restriction. The needle valve 27 is configured such that the user can manually adjust the flow rate of the liquefied carbon dioxide 100 that feeds the secondary pipe L12 according to the use environment of the device such as the outside air temperature and the degree of foaming of the polyurethane foam. Has been.

  The check valve 29 provided in the secondary pipe L12 is configured to flow the liquefied carbon dioxide 100 so that the B liquid in the B liquid pipe L13 communicating with the mixer 31 does not flow into the secondary pipe L12. It regulates the direction.

  The secondary pipe L12b has a small diameter smaller than that of the primary pipe L11. In the first embodiment, the secondary pipe L12b is composed of a 3φ stainless steel pipe. That is, since the flow rate of the liquefied carbon dioxide 100 is different between the upstream side and the downstream side of the needle valve 27, the secondary pipe L12b can be made to have a small diameter to reduce the pressure drop. Since the flow rate of the liquefied carbon dioxide 100 to be fed is reduced, the secondary pipe L12 is in a second pressure state that is lower than the first pressure in the primary pipe L11. The specific value of the second pressure is 4 to 7 MPa, preferably 5 to 6 MPa, and is preferably substantially the same or slightly higher than the discharge pressure (when stopped) of the spray gun 5 of the discharge device 2.

  The B liquid pipe L <b> 13 and the A liquid pipe L <b> 14 feed the B liquid and the A liquid to the spray gun 5 at a pressure pressurized by the supply pumps 31 and 41, respectively.

  Examples of the polyisocyanate that is liquid A include aromatic polyisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and some of the isocyanate groups of aromatic polyisocyanates, aliphatic diisocyanates or alicyclic diisocyanates with urethane and / or Alternatively, those modified with urea may be used, and those obtained by modifying a part of isocyanate groups into burette, allophanate, carbodiimide, oxaziridone, acid, imide and the like may be used.

  Examples of the polyol that is the liquid B include ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexanedimethanol, bisphenol A, 3-methyl-1,5-pentanediol. , Glycerin, trimethylolpropane, pentaerythritol, sucrose, glucose, fructose sorbitol, methylglycoxide and at least one of compounds having active hydrogen. Further, for example, the other active hydrogen-containing compound includes at least one of amines such as ethylenediamine, propylenediamine, diethylenetriamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, and the like. .

  Furthermore, a polyether polyol may be used as the active hydrogen group-containing compound. As the polyether polyol, for example, a monomer such as alkylene oxide is known by using at least one of the above-exemplified active hydrogen compounds as an initiator. What is obtained by addition polymerization by a method is mentioned. Examples of the monomer used for the addition polymerization reaction include ethylene oxide, propylene oxide, glycidyl ether, methyl glycidyl ether, t-butyl glycidyl ether, and phenyl glycidyl ether.

  Further, a polyester polyol may be used as the active hydrogen group-containing compound. Examples of the polyester polyol include ethylene glycol, propanediol, butanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, and hexamethylene glycol. , Decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, at least two compounds having a hydroxyl group such as bisphenol A 1 type, for example, adipic acid, malonic acid, succinic acid, tartaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, azelaic acid, Use at least one of compounds having at least two carboxyl groups such as merit acid, glutaconic acid, α-hydromuconic acid, β-diethylsuccinic acid, hemimellitic acid, 1,4-cyclohexanedicarboxylic acid, etc. And those produced by known methods.

  Furthermore, in addition to the above polyester polyol, a polyester polyol produced by transesterification of a polyalkylene terephthalate polymer and a low molecular diol can also be used. Examples of the low molecular weight diol include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, and cyclohexanedimethanol.

  The catalyst for proceeding the urethanation reaction between the polyisocyanate and the active hydrogen group-containing compound is not particularly limited, and for example, a known catalyst can be used. Further, the foam stabilizer is not particularly limited, and for example, all those used in the production of polyurethane foam can be used. Further, additives such as a catalyst, a foam stabilizer, a flame retardant and the like are usually mixed on the B liquid side. The polyurethane foam of the present invention includes polyisocyanurate foam.

  The pressure in the B liquid pipe L13 and the A liquid pipe L14, that is, the discharge pressure of the spray gun 5 is controlled by the supply pumps 31 and 41 to be a constant pressure (4 to 6 MPa). As the supply pumps 31 and 41, for example, a double-acting proportioning pump that can send liquid to the spray gun 5 at both the up and down strokes of the pump with one piston and one cylinder can be used. The pressure in the B liquid pipe L13 and the A liquid pipe L14 is driven by the supply pumps 31 and 41, because the B liquid and the A liquid pulsate in the B liquid pipe L13 and the A liquid pipe L14. Although it fluctuates, when the supply pumps 31 and 41 are stopped, they are configured to be equal to or higher than a predetermined threshold pressure (for example, about 5 MPa). That is, as shown in FIG. 3, the supply pumps 31 and 41 are configured such that the piston is moved by a pressure adjusting mechanism 50 such as an air cylinder or a hydraulic cylinder, so that the liquid B and the liquid A are always supplied at a constant pressure. It is configured. For example, when the spray gun 5 is operated and the liquid in the B liquid pipe L13 and the A liquid pipe L14 is consumed, the discharge pressure in the B liquid pipe L13 and the A liquid pipe L14 decreases. The supply pumps 31 and 41 are driven to adjust the discharge pressure to be equal to or higher than the threshold pressure (for example, about 5.5 MPa).

  As described above, the internal pressure in the secondary pipe L12 is adjusted by feeding the liquefied carbon dioxide 100 by the on-off valve 26 and adjusting the degree of opening (throttle amount) of the needle valve 27 to the secondary pipe L12. As a result of the decrease in the flow rate of the liquefied carbon dioxide 100, the pressure is reduced to the second pressure. Therefore, the secondary pressure system in the secondary pipe L12, the B liquid pipe L13, and the A liquid pipe L14 adjusts the pressures of the A liquid and the B liquid by driving the supply pumps 31 and 41, and opens and closes. Liquefied carbon dioxide 100 supplied from the primary pressure system in the primary pipe L11 due to the pressure difference between the primary pressure system and the secondary pressure system by switching between opening and closing by the valve 26 and adjusting the throttle amount of the needle valve 27. The flow rate is adjusted. As a result of adjusting the flow rate of the liquefied carbon dioxide 100, the pressure of the secondary pressure system becomes substantially uniform.

  In the polyurethane foam manufacturing apparatus according to the first embodiment, the adjustment (measurement) of the flow rate of the liquefied carbon dioxide 100 is automated by switching the opening / closing valve 26 in conjunction with the operation of the supply pumps 31, 41. It is configured. More specifically, the switching of the on-off valve 26 linked to the operation of the supply pumps 31 and 41 is configured to be performed by the switch 51 and the control unit 10 which are examples of the supply pump drive detection unit. This further eliminates the need for a separate pump for adjusting (measuring) the flow rate of the liquefied carbon dioxide 100. In the first embodiment, the switch 51 and the control unit 10 constitute valve control means.

  The switch 51 is composed of, for example, a micro switch or a limit switch. As shown in FIG. 3, when the pistons of the supply pumps 31 and 41 move (when moving between the solid line and the dotted line in the figure), a part of them (for example, It arrange | positions so that it may physically contact the flange) provided in the outer peripheral part of the piston. When the switch 51 physically contacts a part of the supply pumps 31 and 41, the switch 51 outputs a switch signal, which is an example of a drive detection signal, to the control unit 10.

  The control unit 10 includes a central control unit 11, a switch signal detection unit 12 that is an example of a signal detection unit that detects a switch signal of the switch 51, a timer unit 13 that counts a predetermined time, and a trigger that opens and closes the on-off valve 26. And a trigger signal transmitter 14 for transmitting a signal.

  When the switch signal detection unit 12 receives the switch signal of the switch 51, the central control unit 11 causes the trigger signal transmission unit 14 to transmit a trigger signal for opening the on-off valve 26, and the timer unit 13 has a predetermined time T. The count (for example, about 3 seconds) is started. When the count of the predetermined time T of the timer unit 13 is completed, the central control unit 11 causes the trigger signal transmission unit 14 to transmit a trigger signal that causes the on-off valve 26 to be closed. As a result, as shown in the graph on the left side of FIG. 5, the opening / closing valve 16 is opened until the predetermined time T elapses after the switch signal detection unit 12 detects the switch signal, and 2 from the primary pressure system. The liquefied carbon dioxide 100 is supplied to the secondary pressure system, and the pressure of the secondary pressure system is adjusted to be equal to or higher than the threshold pressure.

  Further, as shown in the graph on the right side of FIG. 5, the supply pumps 31 and 41 are continuously driven, and before the timer unit 13 completes the counting of the predetermined time T, the switch signal detection unit 12 performs a new switch. When the signal is detected, the central control unit 11 resets the count of the predetermined time T of the timer unit 13 and performs control so that the timer unit 13 starts counting the predetermined time T again. While the supply pumps 31 and 41 are being driven, the pressure of the secondary pressure system is lower than the threshold pressure. Therefore, the control uses the pressure of the secondary pressure system higher than the primary pressure system, The pressure of the primary pressure system can be recovered to the threshold pressure or higher at an early stage.

  In addition, due to the pulsation of the supply pumps 31 and 41, the pressure in the B liquid pipe L13 and the A liquid pipe L14, that is, the discharge pressure of the spray gun 5 is temporarily higher than the second pressure in the secondary pipe L12. Although it may become high, the backflow of the B liquid and / or A liquid in the secondary piping L12 in that case is prevented by the check valve 29.

  Next, the operation of the polyurethane foam manufacturing apparatus according to the first embodiment will be described. First, the preparation procedure performed before manufacturing a polyurethane foam using the polyurethane foam manufacturing apparatus concerning this 1st Embodiment is demonstrated.

  In the first embodiment, first, the liquefied carbon dioxide container 20, the polyol component storage container 30, and the polyisocyanate component storage container 40 that are raw materials are connected using various pipes L <b> 11 to L <b> 14, and then inside the pipes L <b> 13 and L <b> 14. Are filled with liquid B and liquid A, respectively.

  Next, the liquefied carbon dioxide 100 is filled into the primary pipe L11. In this operation, the liquefied carbon dioxide 100 is fed into the primary pipe L11 with the on-off valve 26 closed. However, since air or the like is present in the primary pipe L11, one end must be opened. In this case, the liquefied carbon dioxide 100 cannot be filled. Therefore, in the polyurethane foam manufacturing apparatus 1 according to the first embodiment, the primary pipe L11 is provided with the blow valve 24 and the primary pipe L11 is filled with the liquefied carbon dioxide 100. For this reason, the position where the blow valve 24 is provided is preferably in the vicinity of the upstream side of the on-off valve 26 of the primary pipe L11. By providing the blow valve 24 in this manner, the trouble at the time of starting up the apparatus can be facilitated, and the liquefied carbon dioxide 100 remaining in the pipe can be discharged when the apparatus is stopped, and the pressure can be released. .

  After the filling, the liquefied carbon dioxide container 20 is heated by the heating member 21, and the pressure in the primary pipe L11 is adjusted to the first pressure (7 to 8 MPa). Note that the temperature control of the heating member 21 may be configured to be controlled by a computer so as to maintain the first pressure based on the output value of the first pressure gauge 25, for example.

Thereafter, the on-off valve 26 and the needle valve 27 are opened, the liquefied carbon dioxide 100 is filled in the secondary pipe L12, and the throttle amount (opening degree) of the needle valve 27 is adjusted. The pressure in the secondary pipe L12 naturally decreases due to a decrease in the flow rate of the liquefied carbon dioxide 100, and is almost balanced with the pressure (4 to 6 MPa) in the B liquid pipe L13 and the A liquid pipe L14. The throttle amount of the needle valve 27 may be adjusted according to the outside air temperature when the polyurethane foam manufacturing apparatus 1 is used, for example. The throttle amount of the needle valve 27 is preferably adjusted so that, for example, the flow rate of the liquefied carbon dioxide 100 is increased when the outside air temperature is low, and the flow rate is decreased when the outside temperature is high.
When the pressure in the secondary pipe L12 becomes the second pressure, the on-off valve 26 is closed. Thereby, the preparatory process for manufacturing a polyurethane foam is completed.

  In addition, adjusting the 1st pressure to 7-8 Mpa as mentioned above is based on the phase state of a carbon dioxide. That is, carbon dioxide has a relationship as shown in the state diagram shown in FIG. 6 and has a critical point (7.382 MPa (abs), 31.1 ° C.). Therefore, as long as the pressure near the critical point is maintained, carbon dioxide does not become a gas. Therefore, by setting the first pressure to 7 to 8 MPa, the liquid state can be maintained if the temperature in the primary pipe L11 is about room temperature (for example, 20 ° C.).

  In general, it is said that the discharge pressure of the discharge device 2 is 4 to 7 MPa, preferably about 5 to 6 MPa. If the second pressure is set lower than this, the liquefied carbon dioxide 100 is added to the B liquid pipe L13. Can not supply. For this reason, the second pressure is set to a pressure that is substantially the same as or slightly larger than the discharge pressure. In addition, even after the adjustment (measurement) of the flow rate that passes through the needle valve 27 and is supplied to the liquid A and / or the liquid B is completed, even if the liquefied carbon dioxide 100 is vaporized, it is particularly large in the production of polyurethane foam. There is no problem.

  When the preparation step is completed, polyurethane foam is manufactured by the polyurethane foam manufacturing apparatus 1. Hereafter, the manufacturing process of a polyurethane foam is demonstrated, referring FIG.1, FIG.3, FIG.4, FIG.5 and FIG. FIG. 7 is a flowchart showing the operation of the control unit 10.

  First, the spray gun 5 shown in FIG. 1 is operated, and the liquid A, liquid B, and liquefied carbon dioxide 100 supplied into the discharge device 2 in the preparation step are mixed while being heated by the heater 3 and the hose heater 4. Then, the liquid mixture is discharged from the spray gun 5. At this time, the liquid mixture discharged from the spray gun 5 vaporizes the liquefied carbon dioxide 100 and reacts and solidifies to form polyurethane foam. At this time, the discharge from the spray gun 5 consumes the A and B liquids in the A liquid pipe L14 and the B liquid pipe L13, and the liquefied carbon dioxide 100 in the secondary pipe L12. The pressure (pressure of the secondary pressure system), that is, the discharge pressure decreases.

  When the discharge pressure becomes lower than a predetermined threshold pressure (for example, about 5 MPa), the supply pumps 31 and 41 are driven to supply the A liquid and the B liquid into the A liquid pipe L14 and the B liquid pipe L13, respectively. . At this time, when the supply pumps 31 and 41 that move the piston contact the switch 51 as shown in FIG.

When the switch signal detection unit 12 (see FIG. 4) detects the switch signal (step S1), the central control unit 11 transmits a trigger signal that causes the trigger signal transmission unit 14 to open the on-off valve 26 (step S1). Along with S2), the timer section 13 starts counting for a predetermined time T (step S3).
When the on-off valve 26 is opened by step S2, the liquefied carbon dioxide 100 is sent into the secondary pipe L12. At this time, the flow rate of the liquefied carbon dioxide 100 decreases according to the throttle amount of the needle valve 27, and the pressure is adjusted so that the inside of the secondary pipe L12 becomes the second pressure (for example, 5 to 6 MPa).

After step S3, the central control unit 11 determines whether or not the timer 13 has completed counting the predetermined time T (step S4).
When the counting is completed in step S4, the central control unit 11 causes the trigger signal transmission unit 14 to transmit a trigger signal for closing the on-off valve 26 (step S7).
When the count is not completed in step S4, the central control unit 11 determines whether or not the switch signal detection unit 12 further detects a switch signal (step S5). That is, it is determined whether or not the pistons of the supply pumps 31 and 41 are continuously moved.

In step S5, when the switch signal detection unit 12 does not detect a new switch signal, the central control unit 11 proceeds to step S4.
In step S5, when the switch signal detection unit 12 detects a new switch signal, the central control unit 11 resets the count of the predetermined time T of the timer unit 13 (step S6), and then proceeds to step S3. Thus, the timer unit 13 starts counting the predetermined time T.

When the pressure of the secondary pressure system becomes equal to or higher than a predetermined threshold pressure by driving the supply pumps 31 and 41 and opening the on-off valve 26, the drive of the supply pumps 31 and 41 is stopped. In this case, since the switch 51 does not transmit a switch signal, the timer unit 13 can complete the counting of the predetermined time T.
When the counting is completed in step S4, the central control unit 11 causes the trigger signal transmission unit 14 to transmit a trigger signal for closing the on-off valve 26 (step S7).

With the above operation, the pressure of the secondary pressure system is restored to the second pressure.
The operations in steps S1 to S7 may be performed while discharging the mixed liquid by the spray gun 5, or the operation of the spray gun 5 is continued until the reduced secondary pressure system pressure returns to the second pressure. You may make it not accept.

As described above, according to the polyurethane foam manufacturing apparatus 1 according to the first embodiment, the open / close valve 26 is switched according to the supply operation of the liquid A and the liquid B, whereby the liquefied carbon dioxide container The liquefied carbon dioxide 100 is fed to the secondary pressure system using the pressure difference between the inside 20 and the discharge pressure (pressure difference between the primary pressure system and the secondary pressure system) as the conveying force. Thereby, feeding of the liquefied carbon dioxide 100 can be performed without using a pump, and vaporization of carbon dioxide accompanying use of the pump can be prevented.
Further, the flow rate of the liquefied carbon dioxide 100 to the secondary pipe L12 is adjusted with high accuracy so that the inside of the secondary pipe L12 is lower than the first pressure by the opening / closing valve 26 and the needle valve 27, It is possible to prevent the liquefied carbon dioxide 100 from being fed into the discharge device 2 without restriction by the high first pressure.

  Moreover, according to the polyurethane foam manufacturing apparatus 1 according to the first embodiment, after detecting the start of driving of the supply pumps 31 and 41, the on-off valve 26 is opened until a predetermined time T elapses, and within the predetermined time T When the drive of the supply pumps 31 and 41 is newly detected, the count for the predetermined time T is reset and the count is started again. Thereby, even if the drive time of the supply pumps 31 and 41 (time for moving the piston) is irregular, the on-off valve can be opened for an appropriate time according to the drive time. Therefore, it is possible to stabilize the discharge pressure by adjusting the flow rate of the liquefied carbon dioxide 100 with high accuracy, and it is possible to eliminate the need to strictly measure carbon dioxide using a pump.

  Moreover, according to the polyurethane foam manufacturing apparatus 1 concerning this 1st Embodiment, it comprises so that the drive of the supply pumps 31 and 41 may be detected when the supply pumps 31 and 41 and the switch 51 contact physically. Therefore, the configuration is simple and inexpensive. In addition, the structure which detects the drive of the supply pumps 31 and 41 is not limited to this, For example, you may comprise so that the said drive may be detected using a sensor etc., for example.

  Further, according to the polyurethane foam manufacturing apparatus 1 according to the first embodiment, the first pressure is set to 5 MPa to 8 MPa, and the second pressure and the discharge pressure are set to 4 MPa to 7 MPa, respectively. The liquid state can be maintained. Thereby, since carbon dioxide can be fed to the discharge device 2 in a liquid state (including a supercritical state and a subcritical state), cooling for preventing vaporization of the liquefied carbon dioxide 100 as in the conventional example. There is no need to provide an apparatus, and the apparatus can be reduced in size and cost. For example, when the outside air temperature is high and the pressure in the liquefied carbon dioxide container 20 is the first pressure as in the summer, the liquefied carbon dioxide container 20 can be used as it is, while in the winter. When the outside air temperature is low and the pressure of the liquefied carbon dioxide container 20 is less than the first pressure, the inside of the container can be pressurized to the first pressure using a pressurizing means such as the warmer 3.

<< Second Embodiment >>
FIG. 8 is a diagram schematically showing a configuration of a polyurethane foam manufacturing apparatus 1A according to the second embodiment of the present invention. The polyurethane foam manufacturing apparatus 1A according to the second embodiment shown in FIG. 8 includes a discharge device 2A and a control unit 10A in place of the discharge device 2 and the control unit 10, and further includes an outside air temperature detection unit 60. It differs from the polyurethane foam manufacturing apparatus 1 concerning one Embodiment. Hereinafter, the differences will be mainly described in detail.
The polyurethane foam manufacturing apparatus 1A according to the second embodiment includes the warmers 3a and 3b and the hose heaters 4a and 4b instead of the warmer 3 and the hose heater 4, and is mixed with the A liquid pipe L14. Although it differs from the polyurethane foam manufacturing apparatus 1 according to the first embodiment in that the machine 42 is further provided, since these have been described above, redundant description will be omitted.

  The discharge device 2A further includes an operation unit 6 in addition to the discharge device 2. The operation unit 6 is disposed in a part of the spray gun 5 so that a user who is using the apparatus can easily operate the operation unit 6. The operation unit 6 is provided with an adjustment button or an adjustment knob (not shown) to which adjustment information on the foaming degree of the polyurethane foam discharged from the spray gun 5 is input. The user can obtain a polyurethane foam having a desired foaming degree by operating the adjustment button or the adjustment knob and inputting desired foaming degree information to the operation unit 6.

  In the second embodiment, the degree of foaming of the polyurethane foam is adjusted by adjusting the throttle amount of the needle valve 27. Here, it is assumed that the aperture value can be adjusted by, for example, switching in 10 steps of 1 to 10. As described above, since the liquefied carbon dioxide 100 is easily affected by the outside air temperature (ambient temperature), an appropriate throttle amount of the needle valve 27 varies depending on the outside temperature. For this reason, in the second embodiment, an outside air temperature detection unit 60 is provided. As described above, after the adjustment (measurement) of the flow rate supplied to the liquid A and / or the liquid B is completed, the outside air temperature detection unit 60 is installed on the polyurethane foam even if the liquefied carbon dioxide 100 is vaporized. It is preferable to be provided in the vicinity of the needle valve 27 because there is no particular problem in manufacturing.

  The control unit 10A is configured to control the throttle amount of the needle valve 27 based on the foaming degree adjustment information input to the operation unit 6 and the outside air temperature information detected by the outside air temperature detecting unit 60. Specifically, as shown in FIG. 9, in addition to the control unit 10, the control unit 10A further includes a foaming degree adjustment information receiving unit 15 that receives foaming degree adjustment information, and a needle valve 27 that serves as a reference for the outside air temperature. Are provided with a storage unit 16 that stores information on the reference throttle amount in advance and a throttle amount control signal transmitter 17 that transmits a control signal for the throttle amount to the needle valve 27.

  The foaming degree adjustment information includes, for example, information for adjusting the reference aperture amount in five stages of -2, -1, 0, +1, and +2. The storage unit 16 stores a data table as shown in Table 1 below, for example.

  The control unit 10A determines the optimum throttle amount of the needle valve 27 according to the foaming degree adjustment information received by the foaming degree adjustment information receiving unit 15 and the outside air temperature information detected by the outside air temperature detecting unit 60. For example, when the foaming degree adjustment information is +1 and the outside air temperature information is 10 ° C., the throttle degree is optimally 6 (= 5 + 1).

  The valve control means 10A causes the throttle amount control signal transmitter 17 to transmit a throttle amount control signal for setting the needle valve 27 to the throttle amount (6 in the above example). Thereby, it is possible to automatically switch to the throttle degree of the needle valve 27 in consideration of the outside air temperature and the user's request. In addition, when the outside air temperature changes after the switching, it is preferable to automatically switch to the throttle degree of the needle valve 27 according to the outside air temperature information and the foaming degree adjustment information.

  According to the polyurethane foam manufacturing apparatus 1A according to the second embodiment of the present invention, the opening / closing valve 26 and the throttle degree of the needle valve 27 are controlled by the valve opening / closing means 10A. The adjustment can be performed with higher accuracy, and the need to strictly measure carbon dioxide using a pump can be eliminated.

  Further, according to the polyurethane foam manufacturing apparatus 1A according to the second embodiment of the present invention, the above configuration allows the user to spray without worrying about the difference in the degree of foaming caused by the outside air temperature around the on-off valve 26. By inputting desired foaming degree adjustment information to the operation unit 6 provided in the gun 5, it is possible to automatically switch to the optimum throttle amount of the needle valve 27.

  Further, according to the polyurethane foam manufacturing apparatus 1A according to the second embodiment of the present invention, the operation unit 6 for switching the throttle amount of the needle valve 27 is arranged in the discharge device 2, so that the user can change the throttle amount. There is no need to move close to the needle valve 27. In general, since the liquefied carbon dioxide container 20, the polyol component storage container 30, and the polyisocyanate component storage container 40 are not easy to carry, the length of the A liquid pipe L14 and the B liquid pipe L13 is increased (for example, 100 m). Then, the user carries only the discharge device 2 and uses the device 1A. For this reason, it is possible to drastically reduce the burden on the user by configuring the throttle amount of the needle valve 27 to be automatically controlled as described above.

  In addition, this invention is not limited to the said embodiment, It can implement in another various aspect. For example, in the second embodiment, the throttle degree of the needle valve 27 is automatically adjusted according to the foaming degree adjustment information and the outside air temperature information, but the present invention is not limited to this. For example, the throttle degree of the needle valve 27 may be adjusted according to any one of the foaming degree adjustment information and the outside air temperature information. Even in this case, the flow rate of the liquefied carbon dioxide 100 can be adjusted with higher accuracy than in the past, and the necessity of strictly measuring carbon dioxide using a pump can be eliminated.

In the above description, the needle valve 27 is provided as an example of the throttle mechanism, but the present invention is not limited to this. For example, the on-off valve 26 may be configured to have a throttle mechanism function.
In the above description, the on / off valve 26 is switched between open and closed in conjunction with the driving of the supply pumps 31 and 41. However, the present invention is not limited to this. For example, the opening / closing valve 26 may be switched between open and closed in conjunction with a pressure change in the supply pipes L13 and L14 that triggers the supply pumps 31 and 41 to be driven.

  Since the polyurethane foam production apparatus according to the present invention can solve the problem of vaporization of carbon dioxide due to the use of a pump, liquid (supercritical, subcritical or liquid) carbon dioxide is used as a foaming agent. It is useful as a production apparatus suitable for foaming polyurethane foam to be used.

It is a figure which shows typically the structure of the polyurethane foam manufacturing apparatus concerning 1st Embodiment of this invention. It is a figure which shows the structure of a liquefied carbon dioxide container. It is the elements on larger scale which show the structure of a supply pump. It is a block diagram of the control part of the polyurethane foam manufacturing apparatus concerning 1st Embodiment of this invention. It is a timing chart which shows the relationship between the ON / OFF state of a switch, and the open / close state of an open valve. It is a phase diagram of carbon dioxide. It is a flowchart which shows the manufacturing process of the polyurethane foam using the polyurethane foam manufacturing apparatus of FIG. It is a figure which shows typically the structure of the polyurethane foam manufacturing apparatus concerning 2nd Embodiment of this invention. It is a block diagram of the control part of the polyurethane foam manufacturing apparatus concerning 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polyurethane foam manufacturing apparatus 2 Discharge apparatus 3 Heating machine 4 Hose heater 5 Spray gun 6 Operation part 10 Control part 11 Central control part 12 Switch signal detection part 13 Trigger signal transmission part 20 Liquefied carbon dioxide container 21 Heating member 22 Connector 23 Filter 24 Blow valve 25 1st pressure gauge 26 On-off valve 27 Needle valve 28 2nd pressure gauge 29 Check valve 30 Polyol component storage container 31 B liquid pumps 32, 42 Mixer 40 Polyisocyanate component storage container 41 A liquid pump 50 Pressure adjustment mechanism 51 Switch 60 Outside air temperature detection part L11 Primary piping L12, L12a, L12b Secondary piping L13 B liquid piping L14 A liquid piping

Claims (11)

In producing polyurethane foam by mixing A liquid mainly composed of polyisocyanate, B liquid mainly composed of polyol, and liquefied carbon dioxide as a blowing agent supplied from a liquefied carbon dioxide container,
A supply pump for sending out the A liquid and the B liquid so as to have a predetermined discharge pressure;
A supply pipe for feeding the liquid A and liquid B respectively sent out by the supply pump while maintaining the discharge pressure;
A feed pipe for feeding liquefied carbon dioxide as a blowing agent supplied from a liquefied carbon dioxide container whose inside is higher than the discharge pressure to the supply pipe;
A discharge device for mixing and discharging the liquefied carbon dioxide into at least one of the liquid A and the liquid B;
An on-off valve that is provided in the middle of the feed pipe and switches between feeding and stopping of liquefied carbon dioxide fed through the feed pipe;
Valve control means for switching opening and closing of the on-off valve in conjunction with the supply pump in order to control the flow rate of the liquefied carbon dioxide;
A polyurethane foam manufacturing apparatus comprising:   2. The polyurethane foam manufacturing apparatus according to claim 1, wherein the valve control unit switches opening and closing of the on-off valve so that the on-off valve is opened when the supply pump is driven.   The valve control means changes the open / close valve from the closed state to the open state in conjunction with the start of driving of the supply pump, and changes the open / close valve from the open state to the closed state after a lapse of a predetermined time after the drive of the supply pump is stopped. The apparatus for producing polyurethane foam according to claim 1. The supply pump sends out the A liquid and the B liquid by moving the piston,
The polyurethane foam manufacturing apparatus according to claim 1, wherein the valve control means switches opening and closing of the on-off valve in conjunction with movement of the piston. The valve control means includes a supply pump drive detection unit that detects a drive state of the supply pump based on whether or not it physically contacts the piston, and the supply pump drive state detected by the supply pump drive detection unit Switching the opening and closing of the on-off valve in conjunction with
The polyurethane foam manufacturing apparatus according to claim 4. The valve control means includes
When the supply pump drive detection unit physically contacts the piston when the on-off valve is closed, the open / close valve is changed from the closed state to the open state, and the supply pump drive detection unit physically contacts the piston. When the piston is physically contacted again before a predetermined time elapses, the on-off valve is maintained in an open state, and after the supply pump drive detection unit physically contacts the piston, the piston is again turned on before the predetermined time elapses. The polyurethane foam manufacturing apparatus according to claim 5, wherein the on-off valve is changed from the open state to the closed state when there is no physical contact. The valve control means includes
A supply pump drive detector for detecting the start of driving of the supply pump and transmitting a drive detection signal;
A control unit having a signal detection unit for detecting the drive detection signal, a timer unit for counting a predetermined time, and a trigger signal transmission unit for transmitting a trigger signal for opening and closing the on-off valve;
The controller is
When the signal detection unit detects the drive detection signal, the timer unit starts counting, and the trigger signal transmission unit outputs a trigger signal that causes the on-off valve to be opened from a closed state, and the timer unit When the signal detection unit detects a new drive detection signal before completing the count, the count is reset and the count is started again, and when the timer unit completes the count, the trigger signal The transmitter controls to output a trigger signal for closing the on-off valve;
The polyurethane foam manufacturing apparatus according to claim 1. The supply pump sends out the A liquid and the B liquid by moving the piston,
The supply pump drive detection unit includes a switch that transmits the drive detection signal when the piston physically contacts the piston by movement of the piston.
The polyurethane foam manufacturing apparatus according to claim 7. Furthermore, a throttle mechanism capable of adjusting the flow rate of the liquefied carbon dioxide, and an outside air temperature detection unit for detecting the outside air temperature,
The valve control means automatically controls the throttle amount of the throttle mechanism according to the outside air temperature information detected by the outside air temperature detection unit,
The polyurethane foam manufacturing apparatus according to any one of claims 1 to 8.   The polyurethane foam manufacturing apparatus according to any one of claims 1 to 9, wherein the pressure in the liquefied carbon dioxide container is 5 MPa to 8 MPa, and the discharge pressure is 4 MPa to 7 MPa. In producing polyurethane foam by mixing A liquid mainly composed of polyisocyanate, B liquid mainly composed of polyol, and liquefied carbon dioxide as a blowing agent supplied from a liquefied carbon dioxide container,
A supply pump for sending out the A liquid and the B liquid so as to have a predetermined discharge pressure;
A supply pipe for feeding the liquid A and liquid B respectively sent out by the supply pump while maintaining a pre-discharge pressure;
A feed pipe for feeding liquefied carbon dioxide as a foaming agent supplied from a liquefied carbon dioxide container having a first pressure higher than the discharge pressure to the supply pipe;
A discharge device for mixing and discharging the liquefied carbon dioxide into at least one of the liquid A and the liquid B;
An on-off valve that is provided in the middle of the feed pipe and switches between feeding and stopping of liquefied carbon dioxide fed through the feed pipe;
Using a polyurethane foam production apparatus comprising: a method of producing a polyurethane foam by reacting liquid A and liquid B discharged from the discharge device,
In order to control the flow rate of the liquefied carbon dioxide, the polyurethane foam manufacturing method is characterized by switching the opening and closing of the on-off valve in conjunction with the supply pump.

Images