Liquid feeding device

Abstract

The present invention improves reliability of continuity of liquid feeding from a supply container to a recovery container.　A liquid feeding device 1 sends a liquid from a supply container 2 to a recovery container 3. The liquid feeding device 1 includes a transfer circuit 4 having: a liquid passage L that guides the liquid between the supply container 2 and the recovery container 3; a liquid feed pump 41; a suction source switching means 42 for switching the suction source of the liquid by the liquid feed pump 41 between the supply container 2 and the recovery container 3; and a discharge destination switching means 43 for switching the discharge destination of the liquid by the liquid feed pump 41 between the recovery container 3 and the supply container 2 in conjunction with the operation of the suction source switching means 42. The transfer circuit 4 is configured to alternately switch between a first state in which a forward flow F1 toward the recovery container 3 is generated in the liquid passage L and a second state in which a reverse flow F2 is generated in the liquid passage L by switching with the switching means (42, 43), and the liquid feed amount by a forward flow F1 is set to a value larger than the liquid feed amount by a reverse flow F2.

Description

Liquid delivery device

[0001] The present invention relates to a liquid delivery device that transfers a liquid from a supply container to a collection container.

[0002] In recent years, in the field of flow chemistry, a technique has become known in which a liquid (solution) stored in a supply container is passed through a chemical reaction device (reactor) such as a microwave device to perform continuous chemical synthesis, etc. The liquid that has passed through the chemical reaction device is continuously transferred to a collection container.

[0003] JP 2013-037882 A

[0004] Heterogeneous catalysts, or solid catalysts, are often used to promote chemical reactions in liquids passing through chemical reactors. These solid catalysts are typically packed in the form of multiple fine particles in the internal passages of chemical reactors. As a result, the multiple granular solid catalysts tend to be concentrated downstream in the liquid flow direction in the internal passages. This uneven distribution of multiple granular solid catalysts can lead to phenomena such as blocking, in which solid catalysts bond together and cause clogging, and channeling, in which the passage (flow path) becomes essentially immobilized. These phenomena can impede stable liquid delivery through the liquid passages extending from the supply container to the collection container, leaving room for improvement in terms of liquid delivery continuity. Furthermore, stable liquid delivery is a common challenge not only in fields such as flow chemistry, but also in fields where liquid delivery does not involve a chemical reactor.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid delivery device that can improve the reliability of the continuity of delivery of liquid from a supply container to a recovery container.

[0006] According to one aspect of the present invention, a liquid delivery device that delivers liquid from a supply container to a recovery container includes a transfer circuit having a liquid passage that guides the liquid between the supply container and the recovery container, a liquid delivery pump provided in the liquid passage that sucks and discharges the liquid, a suction source switching means provided in the liquid passage for switching the source of suction of the liquid by the liquid delivery pump between the supply container and the recovery container, and a discharge destination switching means provided in the liquid passage for switching the destination of discharge of the liquid by the liquid delivery pump between the recovery container and the supply container in conjunction with the operation of the suction source switching means, and the transfer circuit is configured to alternately switch between a first state in which a forward flow toward the recovery container is generated in the liquid passage and a second state in which a backward flow toward the supply container is generated in the liquid passage by switching the suction source and the discharge destination using the suction source switching means and the discharge destination switching means, and the amount of liquid delivered by the forward flow is set to a value greater than the amount of liquid delivered by the backward flow.

[0007] According to the liquid delivery device of the present invention, it is possible to provide a liquid delivery device that can improve the reliability of the continuity of delivery of liquid from the supply container to the recovery container.

[0008] 6 is a diagram showing a liquid delivery device according to an embodiment of the present invention; FIG. 7 is an enlarged view of an internal passage of the liquid delivery device; FIG. 8 is a diagram for explaining an example of operation of the liquid delivery device (forward flow liquid delivery); FIG. 9 is a diagram for explaining another example of operation of the liquid delivery device (backward flow liquid delivery); FIG. 10 is a time chart for explaining a switching period of the direction of liquid flow occurring in the internal passage; FIG. 11 is a diagram showing a modified example of the liquid delivery device; FIG. 12 is a diagram for explaining an example of operation of the liquid delivery device shown in FIG. 6; FIG. 13 is a diagram for explaining another example of operation of the liquid delivery device shown in FIG. 6;

[0009]

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram for explaining a liquid delivery device according to an embodiment of the present invention, and in particular shows a schematic configuration of a liquid delivery device 1 according to this embodiment.

[0010] The liquid delivery device 1 is a device that delivers a liquid from a supply container 2 to a recovery container 3. In this embodiment, the liquid delivery device 1 is used as a device for delivering a liquid in a continuous processing device 100 that continuously performs chemical synthesis or the like by causing a liquid to flow through a chemical reaction device (reactor) R.

[0011] 1, in this embodiment, the liquid delivery device 1 is a device that delivers the liquid from the supply container 2 to the collection container 3 via the chemical reaction device R, and functions as a liquid delivery device in the continuous processing device 100. In other words, FIG. 1 shows a schematic configuration of the continuous processing device 100 including the liquid delivery device 1 and the chemical reaction device R. The liquid delivery device 1 is also a device for executing a liquid delivery method that delivers the liquid from the supply container 2 to the collection container 3 via the chemical reaction device R. The continuous processing device 100 is also a device for executing a liquid treatment method that delivers the liquid from the supply container 2 to the collection container 3 via the chemical reaction device R while heat-treating the liquid in the chemical reaction device R.

[0012] Although not particularly limited, in this embodiment, the chemical reaction apparatus R is a resonant cavity microwave apparatus that generates microwaves and heats the liquid (liquid to be treated) using the high-frequency energy of the microwaves. The chemical reaction apparatus R (microwave apparatus) is configured to irradiate the liquid (liquid to be treated) passing through the chemical reaction apparatus R with microwaves. Specifically, the chemical reaction apparatus R has an irradiation chamber Ra therein that irradiates the liquid with microwaves and a cavity resonator R1 that resonates the microwaves, a cylindrical inlet portion R2 for introducing the liquid into the microwave irradiation chamber Ra, and a cylindrical outlet portion R3 for discharging the liquid after reaction (treatment) from the irradiation chamber Ra. In this embodiment, the irradiation chamber Ra is formed as a rectangular prism-shaped cavity (irradiation space), and the cavity resonator R1 has four side walls R1a and two opposing walls R1b.

[0013] As described above, the liquid delivery device 1 is a device that delivers liquid from the supply container 2 to the collection container 3 , and includes the supply container 2 , the collection container 3 , and a transfer circuit 4 .

[0014] The supply container 2 is a storage tank configured to be able to store a predetermined amount of the liquid. The liquid stored in the supply container 2 is, for example, a mixed liquid (raw material mixed liquid) consisting of a solvent and a substrate. In other words, the liquid is a liquid to be treated by heat treatment in the chemical reaction device R. By heat treating the liquid in the chemical reaction device R, a chemical reaction of a reaction target substance, such as a substance (substrate) in the liquid, is promoted, and chemical synthesis or the like is continuously performed in the chemical reaction device R.

[0015] The recovery container 3 is a storage tank that is formed so as to be able to store a predetermined amount of the liquid after passing through the chemical reaction device R and being subjected to heat treatment (in other words, after the chemical reaction).

[0016] The transfer circuit 4 is a circuit for transferring the liquid between the supply container 2 and the recovery container 3, and is mainly composed of a liquid passage L and various devices (liquid delivery pump 41, switching means 42, 43, etc.) described below.

[0017] The liquid passage L is a passage that guides the liquid between the supply container 2 and the recovery container 3. The liquid passage L has a transfer passage 44, an internal passage 5, and a recovery passage 6.

[0018] The transfer passage 44 is a passage that guides the liquid between the supply container 2 and the chemical reaction device R (internal passage 5). The transfer passage 44 has a supply passage 44a, a bypass passage 44b, and a return passage 44c. Each passage element (44a, 44b, 44c) of the transfer passage 44 will be described in detail later.

[0019] The internal passage 5 is a passage that continues from the transfer passage 44 (supply passage 44a) and extends through the interior of the chemical reaction device R, and allows the liquid to circulate. In the illustrated example, the internal passage 5 extends so as to penetrate the chemical reaction device R, and the liquid is guided by the internal passage 5 to pass through the interior of the chemical reaction device R. In other words, in this embodiment, a part of the liquid passage L constitutes the internal passage 5 that passes through the interior of the chemical reaction device R.

[0020] 2 is an enlarged view of the internal passage 5 that passes through the chemical reaction device R. The internal passage 5 is a flow pipe made of, for example, quartz glass, and is formed as a straight pipe with a linear tube axis. The flow pipe serving as the internal passage 5 has a length that passes through the cavity resonator R1 of the chemical reaction device R. The internal passage 5 (flow pipe) is installed so that its tube axis substantially coincides with the center line of the irradiation chamber Ra. The center line of the irradiation chamber Ra coincides with the direction of the electric field generated within the irradiation chamber Ra and is the point where the electric field is strongest.

[0021] In this embodiment, the internal passage 5 (flow pipe) is configured to be detachable from the cavity resonator R1. The center line of the irradiation chamber Ra passes through the center of one opposing wall R1b and the center of the other opposing wall R1b, the cylindrical inlet portion R2 is detachably attached to the center of one opposing wall R1b, and the cylindrical outlet portion R3 is detachably attached to the center of the other opposing wall R1b. The inlet portion R2 is configured to support one end 51 of the flow pipe serving as the internal passage 5 without allowing microwaves introduced into the irradiation chamber Ra to escape to the outside, and the outlet portion R3 is configured to support the other end 52 of the flow pipe serving as the internal passage 5 without allowing microwaves introduced into the irradiation chamber Ra to escape to the outside.

[0022] The flow pipe serving as the internal passage 5 will now be described in further detail. In this embodiment, the internal passage 5 (flow pipe) has a catalyst housing portion 53 capable of housing a plurality of particulate solid catalysts 7. An appropriate type of catalyst is used as the particulate solid catalyst 7 depending on the type of the target substance (substrate) in the liquid. In this embodiment, the catalyst housing portion 53 has a larger diameter than other portions of the internal passage 5 (flow pipe), and catalyst holding members 8 are attached to the upper and lower portions of the catalyst housing portion 53. The catalyst holding member 8 allows the liquid (the liquid to be treated) to pass through, while holding the particulate solid catalyst 7 so that it does not flow out of the catalyst housing portion 53. The catalyst holding member 8 is made of, for example, a filter made of polymer or sintered metal, or cotton, glass wool, or the like.

[0023] 1 , the recovery passage 6 is a passage that guides the liquid between the internal passage 5 (chemical reaction device R) and the recovery container 3. One end of the recovery passage 6 is connected to the other end 52 of the internal passage 5 that protrudes from the outlet R3 of the chemical reaction device R, and the other end of the recovery passage 6 is inserted into the recovery container 3 from the top surface thereof and is located near the bottom wall of the recovery container 3.

[0024] Next, the transfer circuit 4 will be further described with reference to Fig. 1 to Fig. 4. Fig. 3 is a diagram for explaining an example of the operation of the liquid delivery device 1 (forward flow delivery, which will be described later), and Fig. 4 is a diagram for explaining another example of the operation of the liquid delivery device 1 (reverse flow delivery, which will be described later).

[0025] As described above, the transfer circuit 4 is a circuit that transfers the liquid between the supply container 2 and the recovery container 3. Referring to Fig. 1, the liquid delivery device 1 has a controller 9, and the operation of various devices in the transfer circuit 4 is controlled by the controller 9. The controller 9 is configured to also control the operation of, for example, the chemical reaction device R (microwave device).

[0026] The transfer circuit 4 is configured to alternately and repeatedly switch between a first state (see FIGS. 2 and 3) in which a forward flow F1 toward the recovery container 3 is generated in the liquid passage L including the internal passage 5, and a second state (see FIGS. 2 and 4) in which a backward flow F2 toward the supply container 2 (in other words, a backward flow F2 that flows in the opposite direction to the forward flow F1) is generated in the liquid passage L including the internal passage 5. The switching operation in the transfer circuit 4 is controlled by a timer or the like provided in the controller 9.

[0027] Figure 5 is a time chart for explaining the switching period of the direction of liquid flow occurring in the internal passage 5. In Figure 5, the horizontal axis represents time t [sec] starting from the start of operation of the transfer circuit 4, and the vertical axis represents the flow rate V [mL / min] per unit time of the liquid flowing through the internal passage 5 at each time, with different signs for the forward flow F1 (in other words, forward flow) and the backward flow F2 (in other words, reverse flow). The flow rate V of the forward flow F1 is marked with a + sign, and the flow rate V of the backward flow F2 is marked with a - sign.

[0028] The transfer circuit 4 starts from the first state, switches from the first state to the second state only once in one period T (in other words, one cycle time T), and then instantly switches (returns) to the first state when one period T has elapsed, and thereafter performs this operation (switching operation) every period T. One period T is the time (= T1 + T2) obtained by adding the duration T1 of the first state (forward flow F1) and the duration T2 of the second state (backward flow F2).

[0029] 5, in the liquid delivery device 1, the liquid delivery rate Q1 due to the forward flow F1 is set to a value greater than the liquid delivery rate Q2 due to the backward flow F2. In other words, in this embodiment, in the liquid delivery device 1, the liquid delivery rate Q1 of the liquid passing through the chemical reaction device R in the first state is set to a value greater than the liquid delivery rate Q2 of the liquid passing through the chemical reaction device R in the second state. In this embodiment, the flow rate V1 per unit time of the liquid flowing through the internal passage 5 in the first state is the same as the flow rate V2 per unit time of the liquid flowing through the internal passage 5 in the second state. In other words, the absolute value of the flow rate +V1 of the forward flow F1 is set to the same value as the absolute value of the flow rate −V2 of the backward flow F2. The duration T1 of the first state is set to a time longer than the duration T2 of the second state. In this embodiment, by setting V1=V2 and setting T1>T2, the liquid delivery amount Q1 (=V1×T1) of the liquid passing through the chemical reaction device R in the first state is set to a value larger than the liquid delivery amount Q2 (=V2×T2) of the liquid passing through the chemical reaction device R in the second state (i.e., Q1>Q2). Therefore, the substantial liquid delivery amount (effective liquid delivery amount) of the liquid delivered by the liquid delivery device 1 from the supply container 2 to the recovery container 3 in one period T (one cycle time T) is the amount (=Q1−Q2) obtained by subtracting the liquid delivery amount Q2 from the liquid delivery amount Q1.

[0030] In this embodiment, as described above, the internal passage 5 has the catalyst containing section 53. Therefore, in the catalyst containing section 53, a forward flow F1 is formed in the first state, and a backward flow F2 is formed in the second state.

[0031] The transfer circuit 4 has a liquid feed pump 41, a suction source switching means 42, a discharge destination switching means 43, and a liquid passage L including a transfer passage 44. The main components of the transfer circuit 4 (liquid feed pump 41, a suction source switching means 42, and a discharge destination switching means 43) are provided in a transfer passage 44 (a passage that guides the liquid between the supply container 2 and the internal passage 5) of the liquid passage L. That is, in this embodiment, the main components of the transfer circuit 4 are arranged together upstream of the internal passage 5 when viewed in the flow direction of the forward flow F1.

[0032] The liquid feed pump 41 is provided in the transfer passage 44 of the liquid passage L and is a pump that sucks in and discharges the liquid. The liquid feed pump 41 has, for example, a maximum discharge pressure of about 5 MPa and a set discharge flow rate of about 0.01 to 100 mL / min, and is a pump that can continuously feed the liquid at high pressure. In this embodiment, the liquid feed pump 41 has a liquid suction port 41a and a liquid discharge port 41b, and in both the first state and the second state, the liquid is sucked in through the suction port 41a and discharged from the discharge port 41b.

[0033] The suction source switching means 42 is provided in the transfer passage 44 of the liquid passage L, and is a switching means for switching the suction source of the liquid by the liquid feed pump 41 between the supply container 2 and the recovery container 3 (in other words, the internal passage 5, further, the chemical reaction device R). In a first state, the suction source switching means 42 switches the suction source to the supply container 2, and in a second state, switches the suction source to the recovery container 3 (the internal passage 5, the chemical reaction device R).

[0034] In the illustrated example, the suction source switching means 42 is an electromagnetically driven three-way valve provided in the transfer passage 44. The suction source switching means 42 is configured to form a passage in the transfer passage 44 that connects the suction port 41 a of the liquid feed pump 41 to the supply container 2 in the first state, and to form a passage in the transfer passage 44 that connects the suction port 41 a of the liquid feed pump 41 to one end 51 of the internal passage 5 in the second state.

[0035] The discharge destination switching means 43 is provided in the transfer passage 44 of the liquid passage L, and is a switching means for switching the discharge destination of the liquid by the liquid feed pump 41 between the collection container 3 (in other words, the internal passage 5, further, the chemical reaction device R) and the supply container 2 in conjunction with the operation of the suction source switching means 42. The discharge destination switching means 43 switches the discharge destination to the collection container 3 (the internal passage 5, the chemical reaction device R) in a first state, and switches the discharge destination to the supply container 2 in a second state.

[0036] In the illustrated example, the discharge destination switching means 43 is an electromagnetically driven three-way valve provided in the transfer passage 44. The discharge destination switching means 43 is configured to form a passage in the transfer passage 44 that connects the discharge port 41 b of the liquid feed pump 41 to one end 51 of the internal passage 5 in the first state, and to form a passage in the transfer passage 44 that connects the discharge port 41 b of the liquid feed pump 41 to the supply container 2 in the second state.

[0037] The transfer circuit 4 is configured such that (1) the suction source is switched to the supply container 2 by the suction source switching means 42 and the discharge destination is switched to the recovery container 3 (internal passage 5, chemical reaction device R) by the discharge destination switching means 43, thereby switching to a first state in which a forward flow F1 is generated in the liquid passage L (internal passage 5), and (2) the suction source is switched to the recovery container 3 (internal passage 5, chemical reaction device R) by the suction source switching means 42 and the discharge destination is switched to the supply container 2 by the discharge destination switching means 43, thereby switching to a second state in which a backward flow F2 is generated in the liquid passage L (internal passage 5). In other words, the transfer circuit 4 is configured to alternately switch between the first state in which a forward flow F1 toward the recovery container 3 is generated in the liquid passage L and the second state in which a backward flow F2 toward the supply container 2 is generated in the liquid passage L by switching the suction source and the discharge destination by the suction source switching means 42 and the discharge destination switching means 43.

[0038] More specifically, the transfer passage 44 of the liquid passage L of the transfer circuit 4 has a supply passage 44a, a bypass passage 44b, and a return passage 44c. Each passage (44a, 44b, 44c) of the transfer passage 44 is formed of a pipe made of an appropriate material.

[0039] The supply passage 44a is a passage that guides the liquid between the supply container 2 and the internal passage 5 (in other words, the chemical reaction device R). The supply passage 44a has a generally uniform cross-sectional shape throughout the flow direction. One end of the supply passage 44a is inserted into the supply container 2 from the top surface thereof and is located near the bottom wall of the supply container 2. The other end of the supply passage 44a is connected to one end 51 (the chemical reaction device R) of the internal passage 5. The liquid feed pump 41 is provided in the supply passage 44a.

[0040] Here, as the liquid continues to flow through the supply passage 44a, which has the same cross-sectional shape, the flow of the liquid within the supply passage 44a can become generally laminar. In contrast, in this embodiment, a turbulent flow generating unit 10 that disturbs the liquid flow within the liquid passage L (supply passage 44a) is provided near one end of the supply passage 44a. The turbulent flow generating unit 10 is not particularly limited, but may be, for example, a static mixer that forms part of the supply passage 44a. In this case, the turbulent flow generating unit 10 is configured to agitate the liquid, which has been in a laminar flow, by causing the liquid to flow through the static mixer, thereby disturbing the flow of the liquid. Thus, in this embodiment, the liquid delivery device 1 includes a turbulent flow generating unit 10 that is provided in the liquid passage L and disturbs the liquid flow within the liquid passage L. In this embodiment, the turbulent flow forming unit 10 is provided at a position upstream of and close to one end 51 of the internal passage 5 when viewed in the flow direction of the forward flow F1, i.e., near the entrance to the internal passage 5 in the first state. In this embodiment, the liquid passes through the turbulent flow forming unit 10 while repeatedly flowing between the forward flow F1 and the backward flow F2 within the turbulent flow forming unit 10, thereby effectively agitating the liquid. This agitation effectively increases the chance of collisions between substrates in the liquid. In this state, the liquid is sent to the internal passage 5 inside the chemical reaction device R.

[0041] Specifically, the static mixer serving as the turbulent flow generating unit 10 may be, for example, a static mixer with a comb-tooth structure or a vortex-generating structure that has been introduced on the market. However, other configurations (structures) of the turbulent flow generating unit 10 may be used instead of an expensive static mixer. For example, the turbulent flow generating unit 10 may be filled with a plurality of granular particles (beads), or may be an in-line filter with a microporous structure made of polymer or sintered metal. Furthermore, the turbulent flow generating unit 10 may be formed by providing a plurality of protrusions on the inner wall of the tubing that constitutes the supply passage 44a. The turbulent flow generating unit 10 may have any function as long as it has the function of disrupting the liquid flow.

[0042] The bypass passage 44b is a passage connected to the supply passage 44a so as to bypass the liquid feed pump 41. The bypass passage 44b connects a first branch point S1 provided at a predetermined position on the supply passage 44a on the suction port 41a side of the liquid feed pump 41, and a second branch point S2 provided at a predetermined position on the supply passage 44a on the discharge port 41b side of the liquid feed pump 41.

[0043] Return passage 44c is a passage that returns to supply container 2 from third branch point S3, which is provided at a predetermined location on supply passage 44a between liquid feed pump 41 (discharge port 41b) and second branch point S2. One end of return passage 44c is inserted into supply container 2 from the top surface of supply container 2 and is located near the bottom wall of supply container 2. The other end of return passage 44c is connected to third branch point S3 of supply passage 44a.

[0044] Then, (1) the suction source switching means 42 switches the suction source to the supply container 2 by opening and closing the transfer passage 44 so as to allow flow through the first branch point S1 toward the suction port 41a of the liquid delivery pump 41 and block flow through the bypass passage 44b, and the discharge destination switching means 43 switches the discharge destination to the recovery container 3 by opening and closing the transfer passage 44 in conjunction with (synchronization with) the suction source switching means 42 so as to allow flow through the third branch point S3 and the second branch point S2 toward the internal passage 5 (chemical reaction device R) and block flow through the return passage 44c. Then, (2) the suction source switching means 42 switches the suction source to the recovery container 3 by opening and closing the transfer passage 44 so as to block the flow passing through the first branch point S1 toward the suction port 41a of the liquid delivery pump 41 and allow the flow to pass through the bypass passage 44b, and the discharge destination switching means 43 switches the discharge destination to the supply container 2 by opening and closing the transfer passage 44 so as to block the flow passing through the third branch point S3 and the second branch point S2 toward the internal passage 5 and allow the flow to pass through the return passage 44c.

[0045] In this embodiment, as described above, the suction source switching means 42 and the discharge destination switching means 43 are each an electromagnetically driven three-way valve. Each switching means (42, 43) has a first port P1, a second port P2, and a third port P3. The ports (P1, P2, P3) and the internal passages of each three-way valve constitute a part of the transfer passage 44. The suction source switching means 42 is located at the first branch point S1, and the discharge destination switching means 43 is located at the third branch point S3. In each switching means (42, 43), the first port P1 is always open, the second port P2 is open when de-energized and closed when energized (i.e., normally open), and the third port P3 is closed when de-energized and open when energized (i.e., normally closed). Note that in FIGS. 3 and 4 , open ports are indicated by solid black, and closed ports are indicated by white. The suction source switching means 42 has the same operational performance as the discharge destination switching means 43, and for example, a three-way valve of the same type as the three-way valve serving as the discharge destination switching means 43 is employed.

[0046] In the suction source switching means 42, the first port P1 is connected to the suction port 41a of the liquid feed pump 41 via the supply passage 44a, the second port P2 is connected to the supply container 2 via the supply passage 44a, and the third port P3 is connected to the bypass passage 44b. In the discharge destination switching means 43, the first port P1 is connected to the discharge port 41b of the liquid feed pump 41 via the supply passage 44a, the second port P2 is connected to one end 51 of the internal passage 5 via the supply passage 44a, and the third port P3 is connected to the return passage 44c.

[0047] The driving of each switching means (42, 43) is controlled by the controller 9. As shown in Fig. 3, each switching means (42, 43) allows flow between P1 and P2 and blocks flow between P1 and P3 and between P2 and P3 when not energized (initial state). Then, as shown in Fig. 4, when each switching means (42, 43) is energized, it blocks flow between P1 and P2 and between P2 and P3 and allows flow between P1 and P3.

[0048] Next, we will explain the operation of the liquid delivery device 1 configured as above. In the initial state, power is not supplied to the switching means (42, 43), and the transfer circuit 4 is in a state where a forward flow F1 can be generated in the internal passage 5 when the liquid delivery pump 41 is started.

[0049] First, when the liquid supply pump 41 is activated, the transfer circuit 4 enters a first state in which a forward flow F1 toward the recovery container 3 is generated in the liquid passage L (internal passage 5). In the first state, the transfer circuit 4 fully opens the supply passage 44a, forming a passage that passes through the first branch point S1 (specifically, the second port P2 and the first port P1 in the suction source switching means 42), the liquid supply pump 41, the third branch point S3 (the first port P1 and the second port P2 in the discharge destination switching means 43), and the second branch point S2. In the first state, the liquid supply pump 41 sucks and discharges the liquid, causing the liquid to flow in the order of the supply container 2 → the supply passage 44a → the internal passage 5 → the recovery passage 6, and then into the recovery container 3. In the first state, the forward flow F1 toward the recovery container 3 is generated in the internal passage 5, and the liquid flows toward the recovery container 3 inside the chemical reaction device R (microwave device). Furthermore, when the chemical reaction device R is activated, an electromagnetic field in TM110 mode is excited in the irradiation chamber Ra (i.e., microwaves are irradiated onto the liquid flowing through the internal passage 5). As a result, the liquid introduced into the internal passage 5 is heated by the microwaves, and the temperature of the liquid rises rapidly.

[0050] The liquid then flows into the catalyst containing section 53. In the catalyst containing section 53, the liquid passes through gaps between the plurality of particulate solid catalysts 7. During this passage, the flow of the liquid is disturbed and the liquid is agitated. Therefore, when the liquid passes through the catalyst containing section 53, contact between the target substance to be reacted (substrate) in the liquid and the catalyst is promoted. As a result, in the catalyst containing section 53, the chemical reaction of the liquid is promoted by the particulate solid catalysts 7 and the heat treatment by the chemical reaction device R. Then, due to the forward flow F1, the plurality of particulate solid catalysts 7 are slightly unevenly distributed toward the recovery container 3.

[0051] Thereafter, the liquid after the reaction (processing) flows out from the other end 52 of the internal passage 5 and is guided to the recovery container 3 via the recovery passage 6 and recovered. The transfer circuit 4 maintains the first state for duration T1 from the start of activation of the liquid feed pump 41. After duration T1 has elapsed, the transfer circuit 4 instantaneously switches to the second state in which a backward flow F2 is generated in the liquid passage L (internal passage 5). During this switching, for example, the liquid feed pump 41 is not stopped, and its operation is maintained, and the chemical reaction device R also continues to irradiate the liquid with microwaves without stopping. In the second state, the suction source switching means 42 and the discharge destination switching means 43 are each energized. As a result, the transfer circuit 4 forms a passageway that passes through the second branch point S2, the bypass passage 44b, the first branch point S1 (specifically, the third port P3 and the first port P1 of the suction source switching means 42), the liquid feed pump 41, the third branch point S3 (the first port P1 and the third port P3 of the discharge destination switching means 43), and the return passage 44c. In the second state, the liquid feed pump 41 sucks and discharges the liquid, thereby sending the liquid in the following order: recovery container 3 → recovery passage 6 → internal passage 5 → supply passage 44a → second branch point S2 → bypass passage 44b → first branch point S1 (suction source switching means 42) → liquid feed pump 41 → third branch point S3 (discharge destination switching means 43) → return passage 44c, and then back into the supply container 2. In the second state, a backward flow F2 toward the transfer circuit 4 is generated in the internal passage 5, and the liquid flows toward the transfer circuit 4 inside the chemical reaction device R (microwave device). Therefore, at the time of this switching, the flow of the liquid in the internal passage 5 is reversed. This reversal effectively agitates the liquid. Furthermore, the plurality of particulate solid catalysts 7 that were unevenly distributed on the recovery container 3 side in the first state are agitated by the reversal and drawn back to the transfer circuit 4 side.

[0052] Thereafter, the transfer circuit 4 continues in the second state for duration T2. ​​After duration T2 has elapsed, the controller 9 cuts off the power supply to each switching means (42, 43), and the transfer circuit 4 instantly switches (returns) to the first state. Thereafter, the above-described operation (switching operation) is repeated a predetermined number of times. As a result, the liquid delivery device 1 delivers a predetermined amount of the liquid stored in the supply container 2 to the recovery container 3.

[0053] The liquid transfer method performed by the liquid transfer device 1 for transferring the liquid from the supply container 2 to the recovery container 3 via the chemical reaction device R includes at least alternately generating a forward flow F1 and a backward flow F2 in the internal passage 5, and setting the liquid transfer amount Q1 of the liquid passing through the chemical reaction device R in the forward flow F1 to a value greater than the liquid transfer amount Q2 of the liquid passing through the chemical reaction device R in the backward flow F2.

[0054] The liquid treatment method executed by the continuous treatment device 100 (i.e., a liquid treatment method in which the liquid is heat-treated in the chemical reaction device R while being fed from the supply container 2 to the recovery container 3 via the chemical reaction device R) includes at least alternately and repeatedly generating a forward flow F1 and a backward flow F2 in the internal passage 5, and setting the liquid feed rate Q1 of the liquid passing through the chemical reaction device R in the forward flow F1 to a value greater than the liquid feed rate Q2 of the liquid passing through the chemical reaction device R in the backward flow F2.

[0055] In the liquid delivery device 1 according to this embodiment, a portion of the liquid passage L of the transfer circuit 4 constitutes an internal passage 5 that passes through (extends to) the interior of the chemical reaction device R, and the transfer circuit 4 is configured to alternately and repeatedly generate a forward flow F1 toward the recovery container 3 and a backward flow F2 in the opposite direction to the forward flow F1 in the internal passage 5 of the liquid passage L, and further, the liquid delivery amount Q1 by the forward flow F1 (the liquid delivery amount Q1 passing through the chemical reaction device R in the forward flow F1) is set to a value greater than the liquid delivery amount Q2 by the backward flow F2 (the liquid delivery amount Q2 passing through the chemical reaction device R in the backward flow F2). By alternately and repeatedly generating the forward flow F1 and the backward flow F2 in the liquid passage L including the internal passage 5, the liquid and the plurality of particulate solid catalysts 7 are effectively agitated each time the flow direction is reversed, and uneven distribution of the catalyst in the internal passage 5 can be effectively eliminated each time the flow direction is reversed. As a result, phenomena such as blocking (i.e., catalysts bonding together and causing clogging) and channeling (i.e., the substantial immobilization of the passage) are effectively suppressed in the internal passage 5. This increases the opportunities for contact between substances (substrates) reacting in the liquid and between substances in the liquid and the catalyst in the internal passage 5 compared to conventional techniques. Furthermore, by setting the liquid delivery rate Q1 of the forward flow F1 to a value greater than the liquid delivery rate Q2 of the backward flow F2, the liquid delivery device 1 can fulfill its basic function of delivering the liquid from the supply container 2 to the recovery container 3. As described above, the liquid delivery device 1, the liquid delivery method, and the liquid treatment method according to this embodiment can easily increase the opportunities for contact between the reaction target substance and a reaction-promoting substance such as a catalyst in the internal passage 5 (chemical reactor R), thereby stabilizing the reaction in the chemical reactor R and the yield of the reaction product. In this way, the liquid delivery device 1 prevents the stable delivery of liquid in the liquid passage L extending from the supply container 2 to the collection container 3 from being hindered, and the liquid delivery device 1 is a device that can improve the reliability of the continuity of liquid delivery from the supply container 2 to the collection container 3.

[0056] The transfer circuit 4 is configured to alternately switch between a first state in which a forward flow F1 toward the collection container 3 is generated in the liquid passage L and a second state in which a backward flow F2 toward the supply container 2 is generated in the liquid passage L by switching the suction source and the discharge destination using the suction source switching means 42 and the discharge destination using the discharge destination switching means 43. In other words, the transfer circuit 4 is configured to switch to the first state by switching the suction source of the liquid by the liquid feed pump 41 to the supply container 2 using the suction source switching means 42 and switching the discharge destination of the liquid by the liquid feed pump 41 to the collection container 3 using the discharge destination switching means 43, and to switch to the second state by switching the suction source to the collection container 3 using the suction source switching means 42 and switching the discharge destination to the supply container 2 using the discharge destination switching means 43; As a result, the liquid delivery device 1 can switch between the first state and the second state simply by controlling the switching means (42, 43) without performing any special control on the liquid delivery pump 41. Therefore, the liquid delivery device 1 can switch between the first state and the second state with simple control. For example, even if the liquid delivery pump 41 cannot perform reverse rotation drive and the suction port 41a and the discharge port 41b of the liquid delivery pump 41 are fixed as in this embodiment, alternating switching between the first state and the second state can be performed instantaneously by simply switching the suction source and the discharge destination of the liquid delivery pump 41. Furthermore, a liquid delivery pump that does not have a structure capable of performing reverse rotation drive can be used as the liquid delivery pump 41, and a small-volume, high-pressure liquid delivery pump that cannot perform reverse rotation drive can also be used as the liquid delivery pump 41.

[0057] In this embodiment, as described above, the condition Q1>Q2 is satisfied by setting V1=V2 and setting T1>T2. This allows the switching operation of the transfer circuit 4 to be performed periodically simply by setting the duration T1 of the first state and the duration T2 of the second state using a timer or the like in the controller 9. As a result, switching between the first state and the second state can be performed with even simpler control.

[0058] In this embodiment, the liquid delivery device 1 includes a turbulence generating unit 10 that is provided in the liquid passage L and that disturbs the liquid flow within the liquid passage L. As a result, the turbulence generating unit 10 can disturb the liquid flow within the liquid passage L in both the first state and the second state. Therefore, even in cases where long-term laminar flow can cause foreign matter to adhere to the inner wall of the liquid passage L, the turbulence generating unit 10 can effectively suppress the adhesion of foreign matter to the inner wall. Furthermore, as in this embodiment, by providing the turbulence generating unit 10 near the entrance to the internal passage 5 in the first state, the liquid is introduced into the internal passage 5 in the first state with the substrate uniformly dispersed in the solvent. As a result, the reaction is stabilized.

[0059] In this embodiment, the liquid delivery device 1 has one supply container 2 and supplies one type of liquid (one liquid) to the chemical reaction device R, but is not limited to this and may be configured to supply a mixed liquid of two liquids to the chemical reaction device R, as shown in Figures 6 to 8. Figure 6 is a diagram showing a modified example of the liquid delivery device 1, Figure 7 is a diagram for explaining one example of the operation of the liquid delivery device 1 shown in Figure 6 (forward flow liquid delivery), and Figure 8 is a diagram for explaining another example of the operation of the liquid delivery device 1 shown in Figure 6 (backward flow liquid delivery).

[0060] 6, the liquid delivery device 1 further includes another supply container 2′ for storing a liquid (hereinafter referred to as reagent liquid B) different from the liquid (hereinafter referred to as reagent liquid A), a mixing section 11 for mixing the reagent liquid A and the reagent liquid B, and another transfer circuit 4′ for transferring the reagent liquid B between the other supply container 2′ and the mixing section 11. The other transfer circuit 4′ is configured to alternately switch between a third state corresponding to the first state and a fourth state corresponding to the second state in synchronization with a suction source switching means 42 and a discharge destination switching means 43 (described later) of the transfer circuit 4, and the amount of liquid delivered by the other transfer circuit 4′ in the third state is set to a value higher than the amount of liquid delivered by the other transfer circuit 4′ in the fourth state.

[0061] Another supply container 2' is a storage tank configured to be able to store a predetermined amount of reagent solution B. The reagent solution B stored in another supply container 2' is, for example, a mixed solution (raw material mixed solution) consisting of a solvent and a substrate. The substrate contained in the reagent solution A stored in the supply container 2 is a different type of substrate from the substrate contained in the reagent solution B.

[0062] The mixer 11 is provided at a predetermined position in the liquid passage L of the transfer circuit 4 between the destination switching means 43 and the recovery container 3. In this embodiment, the mixer 11 is disposed at a predetermined position in the supply passage 44a of the transfer circuit 4 between the second branch point S2 and the internal passage 5 (the turbulent flow forming section 10 in the illustrated example). In the mixer 11, the reagent solution A and the reagent solution B are mixed, and the mixed liquid containing two types of substrates is supplied to the internal passage 5 (chemical reaction device R), where a catalyst and heat treatment promote a chemical reaction of the mixed liquid of the two liquids. The mixer 11 may be, for example, a T-type joint or a joint with a double-pipe structure.

[0063] The other transfer circuit 4' has the same configuration as the transfer circuit 4, except that the liquid delivery range, suction source, and discharge destination are different from those of the transfer circuit 4. That is, the other transfer circuit 4' includes another liquid passage L' corresponding to the liquid passage L, another liquid delivery pump 41' corresponding to the liquid delivery pump 41, another suction source switching means 42' corresponding to the suction source switching means 42, and another discharge destination switching means 43' corresponding to the discharge destination switching means 43. The other liquid delivery pump 41' preferably has the same operational performance as the liquid delivery pump 41, for example, a pump of the same type as the liquid delivery pump 41 is used. The other suction source switching means 42' and the other discharge destination switching means 43' preferably have the same operational performance as the suction source switching means 42 and the discharge destination switching means 43, for example, a three-way valve of the same type as the three-way valves used as the suction source switching means 42 and the discharge destination switching means 43 is used. Below, the other transfer circuit 4' will be described, mainly focusing on the differences from the transfer circuit 4.

[0064] The other liquid passage L' has the same configuration as the liquid passage L, except that the liquid delivery range is different from that of the liquid passage L. The other liquid passage L' guides the reagent solution B between the other supply container 2' and the mixing section 11 and does not have an internal passage 5 or a recovery passage 6. In the other liquid passage L', one end of a supply passage 44a is inserted into the other supply container 2' from the top surface thereof and positioned near the bottom wall of the other supply container 2', and the other end of the supply passage 44a is connected to the mixing section 11. The supply passage 44a of the other liquid passage L' is provided with a first branch point S1 (another suction source switching means 42'), another liquid delivery pump 41', a third branch point S3 (another discharge destination switching means 43'), and a second branch point S2, in this order, as well as a bypass passage 44b and a return passage 44c, just like the liquid passage L.

[0065] The other liquid feed pump 41′ is provided in the other liquid passage L′, and is a pump that sucks in and discharges the test liquid B, and has the same structure as the liquid feed pump 41. Like the liquid feed pump 41, the other liquid feed pump 41′ is provided in the supply passage 44a of the other liquid passage L′.

[0066] The other suction source switching means 42' is provided in the other liquid passage L' and is a switching means for switching the suction source of the reagent solution B by the other liquid feed pump 41' between the other supply container 2' and the mixing unit 11. The other suction source switching means 42' has the same structure as the suction source switching means 42 and, like the suction source switching means 42, is provided at the first branch point S1 of the supply passage 44a of the other liquid passage L'. In the third state, the other suction source switching means 42' is configured to switch the suction source of the other liquid feed pump 41' to the other supply container 2' by forming a passage in the transfer passage 44 of the other liquid passage L' that communicates the suction port 41a of the other liquid feed pump 41' with the other supply container 2'. In the fourth state, the other suction source switching means 42' is configured to switch the suction source of the other liquid delivery pump 41' to the mixing section 11 by forming a passage in the transfer passage 44 of the other liquid passage L' that connects the suction port 41a of the other liquid delivery pump 41' to one end 51 of the internal passage 5 via the mixing section 11.

[0067] The other discharge destination switching means 43′ is provided in the other liquid passage L′ and is a switching means for switching the discharge destination of the reagent solution B from the other liquid feed pump 41′ between the mixing section 11 and the other supply container 2′ in conjunction with the operation of the other suction source switching means 42′. The other discharge destination switching means 43′ has the same structure as the discharge destination switching means 43 and, like the discharge destination switching means 43, is provided at the third branch point S3 of the supply passage 44a of the other liquid passage L′. In the third state, the other discharge destination switching means 43′ is configured to switch the discharge destination of the other liquid feed pump 41′ to the mixing section 11 by forming a passage in the transfer passage 44 of the other liquid passage L′ that communicates the discharge port 41b of the other liquid feed pump 41′ with one end 51 of the internal passage 5 via the mixing section 11. In the fourth state, the other discharge destination switching means 43' is configured to switch the discharge destination of the other liquid supply pump 41' to another supply container 2' by forming a passage connecting the discharge port 41b of the other liquid supply pump 41' to the other supply container 2' in the transfer passage 44 of the other liquid passage L'.

[0068] The other transfer circuit 4' is configured to alternately and repeatedly switch between a third state in which a forward flow F1 is generated in the liquid passage L through the mixing section 11 and a fourth state in which a backward flow F2 is generated in the liquid passage L through the mixing section 11, by switching the suction source and the discharge destination of the other liquid feed pump 41' by the other suction source switching means 42' and the other discharge destination switching means 43' in synchronization with the suction source switching means 42 and the discharge destination switching means 43 of the transfer circuit 4. The amount of liquid fed by the other transfer circuit 4' in the third state is set to a value greater than the amount of liquid fed by the other transfer circuit 4' in the fourth state.

[0069] As shown in FIGS. 7 and 8 , the controller 9 synchronizes the control of each device in the transfer circuit 4 with the control of each device in the separate transfer circuit 4'. As a result, when the transfer circuit 4 is in the first state and the separate transfer circuit 4' is in the third state, a forward flow F1 of the two-liquid mixture (= A + B) is formed in the internal passage 5 (see FIG. 7 ). When the transfer circuit 4 is in the second state and the separate transfer circuit 4' is in the fourth state, a backward flow F2 of the two-liquid mixture is formed in the internal passage 5 (see FIG. 8 ). Note that when the backward flow F2 is formed, the two-liquid mixture flows into the transfer circuit 4 and the separate transfer circuit 4' through the mixing section 11, which may cause the mixture ratio (quantitativeness) of reagent solution A to deviate from the intended mixture ratio. To address this deviation in the mixture ratio, a reservoir (not shown) for collecting the backflowing mixture may be provided at a predetermined location in the supply passage 44a between the second branch point S2 and the mixing section 11.

[0070] 6 to 8, in the liquid delivery device 1 that delivers a mixture of two liquids, the turbulent flow forming part 10 is provided near the entrance to the internal passage 5 in the first state, so that in the first and third states, the mixture of two liquids is introduced into the internal passage 5 in a more uniformly mixed state, thereby more reliably stabilizing the reaction.

[0071] Furthermore, in the present embodiment and the above-described modified example, each switching device (42, 43, 42', 43') is an electromagnetically driven three-way valve. However, this is not limited thereto. Two two-way valves may be used instead of one three-way valve. That is, each switching device (42, 43, 42', 43') may be configured with two electromagnetically driven two-way valves. In this case, although not shown, in the suction source switching device 42 and the alternative suction source switching device 42', one two-way valve is provided in the bypass passage 44b and the other two-way valve is provided near the first branch point S1 in the supply passage 44a. In addition, in the discharge destination switching device 43 and the alternative discharge destination switching device 43', one two-way valve is provided in the return passage 44c and the other two-way valve is provided near the second branch point S2 in the supply passage 44a. For example, one of the two-way valves is a normally closed type solenoid valve that is closed when not energized and open when energized, and the other two-way valve is a normally open type solenoid valve that is open when not energized and closed when energized.

[0072] The chemical reactor R (i.e., flow reactor), which continuously promotes a reaction while flowing a liquid as described above, can be used for cell culture applications in fields such as biochemistry. In cell culture applications, a liquid such as a culture medium containing dissolved oxygen may be continuously supplied to a cell culture medium provided in a cell culture vessel corresponding to the chemical reactor R to promote cell culture in the culture medium. In such cases, increased contact between the cells being cultured and the oxygen-dissolved culture medium (i.e., the cell culture-promoting substance) is desired. The liquid delivery device 1, the liquid delivery method, and the liquid treatment method can also be used for cell culture applications. In this case, although not shown, instead of the internal passage 5, a cell culture medium is provided inside the chemical reactor R (i.e., cell culture vessel), and the end of the supply passage 44a and the end of the recovery passage 6 of the transfer circuit 4 are connected to this medium. A culture solution is stored as the liquid in the supply container 2, and the culture solution (the liquid) is stored in the supply container 2 in a state in which oxygen (gas) as a culture reaction promoter is dissolved or dispersed in the culture solution (i.e., in a gas-containing state). This increases the opportunity for contact between the cells to be cultured and the oxygen-dissolved culture solution (reaction promoter) in the medium.

[0073] Furthermore, in this embodiment and the above-described modified example, the liquid delivery device 1 is used as a device for delivering liquid in a continuous processing apparatus 100 that continuously performs chemical synthesis, etc., but the application is not limited to this. That is, the liquid passage L of the liquid delivery device 1 does not have to pass through the interior of the chemical reaction apparatus R. In this case, the liquid delivery device 1, during the liquid delivery operation of delivering liquid from the supply container 2 to the recovery container 3, repeatedly generates a forward flow F1 and a backward flow F2 in the liquid passage L, thereby preventing the accumulation of foreign matter on the inner wall (inner wall of the pipe) of the liquid passage L and ensuring stable liquid delivery by the liquid delivery device 1. As a result, the continuity of liquid delivery from the supply container 2 to the recovery container 3 is improved.

[0074] The above describes the embodiments of the present invention and their modifications. However, the present invention is not limited to the above-described embodiments and modifications, and it goes without saying that further modifications and changes are possible based on the technical concept of the present invention.

[0075] 1...liquid delivery device, 2...supply container, 2'...another supply container, 3...recovery container, 4...transfer circuit, 41...liquid delivery pump, 42...suction source switching means, 43...discharge destination switching means, 4'...another transfer circuit, 41'...another liquid delivery pump, 42'...another suction source switching means, 43'...another discharge destination switching means, 5...internal passage, 53...catalyst containing section, 7...plurality of particulate solid catalysts, 10...turbulence forming section, 11...mixing section, F1...forward flow, F2...backward flow, L...liquid passage, L'...another liquid passage, Q1, Q2...liquid delivery amount, R...chemical reaction device (reactor), T1, T2...duration, V1, V2...flow rate

Claims

1. A liquid delivery device for delivering a liquid from a supply container to a collection container, comprising: a transfer circuit having: a liquid passage for directing the liquid between the supply container and the collection container; a liquid delivery pump provided in the liquid passage for sucking and discharging the liquid; a suction source switching means provided in the liquid passage for switching the source of suction of the liquid by the liquid delivery pump between the supply container and the collection container; and a discharge destination switching means provided in the liquid passage for switching the destination of the liquid discharged by the liquid delivery pump between the collection container and the supply container in conjunction with the operation of the suction source switching means, wherein the transfer circuit is configured to alternately switch between a first state in which a forward flow toward the collection container is generated in the liquid passage and a second state in which a backward flow toward the supply container is generated in the liquid passage, by switching the suction source and the discharge destination using the suction source switching means and the discharge destination switching means, and wherein an amount of liquid delivered by the forward flow is set to a value greater than an amount of liquid delivered by the backward flow.

2. The liquid delivery device according to claim 1, wherein a portion of said liquid passage constitutes an internal passage passing through the inside of a chemical reaction device.

3. The liquid delivery device according to claim 2, wherein the internal passage has a catalyst storage section capable of storing a plurality of particulate solid catalysts, and the forward flow is formed in the catalyst storage section in the first state, and the backward flow is formed in the catalyst storage section in the second state.

4. The liquid delivery device according to claim 1, further comprising a turbulence generating section provided in said liquid passage for turbulently flowing liquid within said liquid passage.

5. A liquid delivery device as described in claim 4, wherein a portion of the liquid passage constitutes an internal passage passing through the interior of a chemical reaction device, and the turbulent flow forming portion is provided near an entrance to the internal passage in the first state.

6. The liquid delivery device according to claim 1, wherein the liquid is stored in the supply container in a state where the liquid contains gas.

7. A liquid supply system further comprising: another supply container for storing a liquid other than the liquid mentioned above; a mixing section provided in a predetermined position in the liquid passage between the discharge destination switching means and the recovery container, for mixing the liquid mentioned above with the other liquid; and another transfer circuit for transferring the other liquid between the other supply container and the mixing section, wherein the other transfer circuit has: another liquid passage for guiding the other liquid between the other supply container and the mixing section; another liquid delivery pump provided in the other liquid passage for sucking in and discharging the other liquid; another suction source switching means provided in the other liquid passage for switching the source of suction of the other liquid by the other liquid delivery pump between the other supply container and the mixing section; and another discharge destination switching means provided in the other liquid passage for switching the destination of discharge of the other liquid by the other liquid delivery pump between the mixing section and the other supply container in conjunction with the operation of the other suction source switching means, The liquid delivery device of claim 1, wherein the other transfer circuit is configured to alternately switch between a third state in which the forward flow is generated in the liquid passage through the mixing section and a fourth state in which the backward flow is generated in the liquid passage through the mixing section by switching the suction source and the discharge destination of the other liquid delivery pump by the other suction source switching means and the other discharge destination switching means in synchronization with the suction source switching means and the discharge destination switching means of the transfer circuit, and the amount of liquid delivered by the other transfer circuit in the third state is set to a value greater than the amount of liquid delivered by the other transfer circuit in the fourth state.

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