Liquid supply system

Abstract

To provide a liquid supply system capable of delaying time at which a liquid flow path enters a liquid non-suppliable state after a liquid shortage detector detects liquid shortage.SOLUTION: A liquid supply system 10 includes: a liquid flow path 16 for supplying a liquid supplied from a liquid source 12 to a liquid use part 14; a liquid feed part 18 capable of feeding the liquid in the liquid flow path 16 to the liquid use part 14; a liquid shortage detector 20 that detects liquid shortage of the liquid source 12; and a buffer part 50 that is disposed in the liquid flow path 16 and is capable of temporarily storing the liquid even after the liquid shortage detector 20 detects the liquid shortage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a liquid supply system for supplying liquid. [Background technology]

[0002] Patent Document 1 discloses a liquid supply system including a liquid flow path for supplying liquid in a liquid source to a water supply pipe where the liquid is used, a liquid delivery unit capable of delivering the liquid in the liquid flow path to the water supply pipe, and a liquid shortage detector for detecting liquid shortage in the liquid source. The liquid shortage detector in Patent Document 1 detects liquid shortage based on the number of operations of a pump for sending out liquid in the liquid flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-196635 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the liquid delivery unit continues to deliver liquid after the liquid-out detector detects that the liquid is out of stock, after a while the liquid will enter a state in which the liquid cannot be delivered from the liquid flow path to the liquid-use point. If the liquid flow path enters a state in which liquid cannot be delivered soon after the liquid-out detector detects that the liquid is out of stock, there is a problem that the liquid will not be usable at the liquid-use point for a long period of time until either a new liquid source or new liquid can be obtained.

[0005] Therefore, one object of the present disclosure is to provide a liquid supply system that can delay the time until the liquid flow path becomes unable to supply liquid after the liquid shortage detector detects that the liquid has run out. [Means for solving the problem]

[0006] The first liquid supply system of the present disclosure comprises a liquid flow path for supplying liquid supplied from a liquid source to a point of liquid use, a liquid delivery section capable of delivering liquid in the liquid flow path to the point of liquid use, a liquid-out detector for detecting a shortage of liquid in the liquid source, and a buffer section provided in the liquid flow path and capable of temporarily storing liquid even after a shortage of liquid is detected by the liquid-out detector. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic overall configuration diagram of a liquid supply system according to a first embodiment. [Diagram 2] FIG. 2 is a plan cross-sectional view that illustrates a schematic view of a part of the liquid supply system of the first embodiment. [Diagram 3] 3 is a cross-sectional view showing a schematic diagram of a redundant portion of a tube according to the first embodiment together with a surrounding structure. FIG. [Figure 4] 10 is an explanatory diagram for explaining a problem that occurs when the inner diameter of a redundant portion of a tube is large. FIG. [Diagram 5] 11 is an explanatory diagram for explaining the effect when the inner diameter of the redundant portion of the tube is small. FIG. [Figure 6] FIG. 11 is a plan cross-sectional view that illustrates a schematic view of a part of a liquid supply system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described. The same components are given the same reference numerals, and duplicated explanations will be omitted. In each drawing, for the sake of convenience, components are omitted, enlarged, or reduced as appropriate. The drawings should be viewed according to the orientation of the reference numerals.

[0009] (First embodiment) See Figures 1 and 2. A liquid supply system 10 includes a liquid source 12 capable of storing liquid, a liquid flow path 16 for supplying the liquid supplied from the liquid source 12 to a liquid use point 14, a liquid delivery unit 18 provided in the liquid flow path 16 and capable of delivering the liquid in the liquid flow path 16 to the liquid use point 14, a liquid shortage detector 20 capable of detecting a liquid shortage in the liquid source 12, and a control unit 22 capable of controlling the liquid delivery unit 18. Here, "delivery" means to deliver the liquid.

[0010] In addition, the liquid supply system 10 may optionally include a main flow path 26 that joins with the liquid flow path 16 at a joining point 24 and to which liquid is added from the liquid flow path 16, an on-off valve 28 provided in the main flow path 26, a water purification cartridge 30 provided in the main flow path 26, and a casing 32 that houses the liquid source 12 and the like. In FIG. 2, the flow direction of the liquid flow path 16 is indicated by a solid arrow, and the flow direction of the main flow path 26 is indicated by a dashed-dotted arrow. In FIG. 2, flow path members that form part of the main flow path 26 are omitted, and only the flow direction is shown. The on-off valve 28 is an automatic on-off valve such as a solenoid valve or an electric valve. The water purification cartridge 30 is used to purify the raw water.

[0011] In the main flow path 26, a liquid other than the liquid flowing through the liquid flow path 16 flows. Here, an example of raw water such as tap water or natural water flows as the "other liquid". Here, the "raw water" refers to a solvent to which the liquid in the liquid source 12 is added. The main flow path 26 is used to supply the other liquid to a supplied device 34. Here, an example is shown in which the supplied device 34 is a discharge device 36 for discharging a liquid, but it may be a tank or the like. The discharge device 36 is, for example, a discharge pipe, a shower head, or a dispenser such as a soap dispenser.

[0012] The casing 32 accommodates at least a part of the liquid flow path 16. The casing 32 of this embodiment also accommodates at least a part of the liquid source 12, the liquid delivery section 18, etc. The casing 32 of this embodiment has a rectangular shape in a plan view, and is fixed to an external member.

[0013] The liquid source 12 of this embodiment is detachably held by a screw mechanism or the like in a liquid source holder 38 fixed to the casing 32. The liquid in the liquid source 12 is used for drinking, for example, as a dilution beverage liquid, a food additive concentrate, a seasoning liquid, etc. In addition, the liquid may be used for applications that come into contact with the human body, such as soapy water, lotion, body oil, etc.

[0014] The liquid use point 14 is a place where the liquid in the liquid source 12 is used. The liquid use point 14 is, for example, either (1) the main flow path 26 or (2) a discharge device for discharging the liquid. In either case of (1) or (2), the liquid flow path 16 directly supplies the liquid to the liquid use point 14. In the case of (1), the liquid flow paths 16 join at a joining point 24 located midway along the flow direction of the main flow path 26, and the liquid of the liquid source 12 is used by being added to another liquid flowing through the main flow path 26. As a result, a mixed liquid is generated by adding the liquid of the liquid source 12 to the liquid on the main flow path 26. In the main flow path 26 in this embodiment, raw water flows as the other liquid, and by adding the liquid to the raw water, diluted water in which the liquid is diluted with the raw water is generated as a mixed liquid. A specific example of the other liquid flowing through the main flow path 26 is not limited to raw water. In the case of (2), the liquid is supplied to the discharge device 36 through the liquid flow path 16 and is used by being discharged from the discharge device 36. In the case of (2), the liquid may be directly supplied to the discharge device 36 as a single-phase liquid flow through the liquid flow path 16, or may be directly supplied to the discharge device 36 as a gas-liquid mixed-phase flow such as cleaning foam made by foaming a cleaning liquid. Here, an example of (1) is shown.

[0015] As an optional configuration, the liquid flow path 16 is provided with a sterilization unit 40 that sterilizes the liquid flowing through the liquid flow path 16. The sterilization unit 40 is configured to sterilize the liquid using, for example, a hollow fiber membrane filter, a photocatalyst, ultraviolet light, or the like.

[0016] The liquid delivery unit 18 of this embodiment can deliver the liquid in the liquid flow path 16 by sending the fluid sucked from the upstream side toward the downstream side. In addition to the pump, the liquid delivery unit 18 of this embodiment includes a driving source such as a motor or a solenoid that drives the pump. The liquid delivery unit 18 can adjust the amount of liquid delivered per unit time under the control of the control unit 22. The pump of the liquid delivery unit 18 is, for example, a tube pump, but various other pumps such as a gear pump and a vane pump may also be used. The liquid delivery unit 18 of this embodiment is configured using a pump, but a specific example thereof is not particularly limited, and may be, for example, a compressor.

[0017] The liquid-out detector 20 includes a sensor 44 that detects a physical quantity that changes depending on the presence or absence of liquid in the detection target portion 42 of the liquid flow path 16, and a liquid-out detection unit 46 that detects liquid out based on the detection result of the sensor 44. Here, "liquid out" does not only mean a case where the liquid source 12 is completely depleted. This "liquid out" also includes a case where, after the liquid source 12 has been drained to the extent that it can be delivered by the liquid delivery unit 18, a small amount of liquid that cannot be delivered by the liquid delivery unit 18 remains in the liquid source 12. The liquid-out detection unit 46 is composed of a computer such as an IC chip.

[0018] An example of the physical quantity to be detected by the sensor 44 is capacitance, but it may be temperature, light amount, etc. In the case where capacitance is detected, when liquid is present in the detection target portion 42 of the liquid flow path 16, the detection value of the capacitance detected by the sensor 44 is larger than when gas is present in the detection target portion 42. The liquid-out detection unit 46 compares the detection value of the sensor 44 with a threshold value set for the detection value of the sensor 44, and detects the liquid out of the liquid based on the comparison result. This threshold value is for determining the presence or absence of liquid in the detection target portion 42 of the liquid flow path 16. For example, when the detection target of the sensor 44 is capacitance, when the detection value is larger than the threshold value, the comparison result indicates that liquid is present in the detection target portion 42 of the liquid flow path 16. On the other hand, when the detection value is smaller than the threshold value, the comparison result indicates that there is no liquid in the detection target portion 42 of the liquid flow path 16, but gas is present. When the detection value of the sensor 44 is the comparison result indicating the presence of liquid, the liquid-out detection unit 46 does not detect the liquid out of the liquid. On the other hand, when the detection value of the sensor 44 is a comparison result indicating the absence of liquid, the liquid shortage detection unit 46 detects the liquid shortage using this as a trigger. When the liquid delivery unit 18 starts the liquid delivery operation, the liquid shortage detector 20 detects the liquid shortage in the liquid source 12 based on the presence or absence of liquid in the detection target portion 42 of the liquid flow path 16.

[0019] When the liquid shortage detector 20 detects the liquid shortage, the liquid shortage may be notified by an alarm unit (not shown). The alarm unit is, for example, a lamp, a display, a speaker, or the like.

[0020] As described above, the liquid out-of-liquid detector 20 detects a liquid out-of-liquid state based on the presence or absence of liquid in the detection target portion 42 of the liquid flow path 16. To achieve this, the liquid supply system 10 is configured so that, when the liquid source 12 runs out of liquid, gas flows through the detection target portion 42 of the liquid flow path 16. To embody this, the liquid supply system 10 of this embodiment employs the following two configurations.

[0021] First, the liquid source 12 is composed of a sealed container capable of shrinking and deforming so that the volume is reduced by suction by the liquid delivery unit 18. The liquid source 12 of this embodiment has a double-cylinder structure including a sealed container capable of shrinking and an outer cylinder that covers the sealed container. By using such a sealed container, it is possible to prevent outside air from entering the sealed container when the sealed container serving as the liquid source 12 runs out of liquid.

[0022] Secondly, the liquid flow path 16 includes a gas reservoir 48 in which gas is stored. The gas reservoir 48 in this embodiment is provided in the sterilization unit 40, but its location is not particularly limited. When there is liquid in the liquid source 12, the liquid delivery unit 18 can deliver the liquid in the liquid flow path 16 by sucking the liquid in the liquid source 12 with a volume reduction deformation of the liquid source 12 while leaving the gas stored in the gas reservoir 48. When the liquid source 12 runs out of liquid, the negative pressure applied to the liquid in the liquid flow path 16 gradually increases due to the suction of the liquid delivery unit 18. As a result, the gas in the gas reservoir 48 begins to expand and is drawn into the liquid flow path 16, and the gas begins to flow through the detection target portion 42 of the liquid flow path 16. In other words, when there is liquid in the liquid source 12, the liquid continues to flow through the detection target portion 42 of the liquid flow path 16, and when the liquid source 12 runs out of liquid, the gas begins to flow through the detection target portion 42. The liquid shortage detector 20 detects the liquid shortage in the liquid source 12 by utilizing the gas stored in the gas reservoir 48.

[0023] The control unit 22 is a computer such as a microcomputer configured by a combination of a CPU, a ROM, and a RAM. The control unit 22 controls the liquid delivery unit 18 to control the amount of liquid delivered per unit time by the liquid delivery unit 18. In this embodiment, the control unit 22 controls the on-off valve 28 to open when the liquid is being delivered by the liquid delivery unit 18. As a result, raw water flows through the main flow path 26, and liquid is added to the main flow path 26 from the liquid flow path 16.

[0024] Here, the liquid supply system 10 of this embodiment includes a buffer section 50 provided in the liquid flow path 16. The buffer section 50 can temporarily store liquid not only before the liquid out-of-liquid detector 20 detects the liquid out-of-liquid, but also after the liquid out-of-liquid detector 20 detects the liquid out-of-liquid. The buffer section 50 is provided to delay the time until the liquid cannot be supplied to the liquid use location 14 when the liquid delivery section 18 continues to deliver liquid after the liquid out-of-liquid detector 20 detects the liquid out-of-liquid, by providing a margin in the amount of liquid stored in the liquid flow path 16. With this objective in mind, the buffer section 50 of this embodiment is provided downstream of the detection target section 42 of the liquid flow path 16.

[0025] The buffer section 50 is composed of either a redundant section 54 provided in a tube 52 that constitutes the liquid flow path 16, or a tank. The tank here refers to a tank that has a storage chamber whose cross section perpendicular to the flow direction on the liquid flow path 16 is larger than the portions that continue forward and backward in the flow direction. Here, an example will be described in which the buffer section 50 is composed of the redundant section 54 of the tube 52.

[0026] The redundant portion 54 is provided in a portion of the longitudinal range of the tube 52 to provide some slack in the length of the tube 52. One end of the tube 52 is connected to a first connecting member 56, and the other end is connected to a second connecting member 58. Here, the first connecting member 56 is the sterilization section 40, and the second connecting member 58 is the liquid delivery section 18. The redundant portion 54 of the tube 52 in this embodiment is provided in a location other than the space between the first connecting member 56 and the second connecting member 58.

[0027] Please refer to Figures 2 and 3. The redundant portion 54 is composed of at least one of the wound shape portions 60A, 60B having a wound shape and the meandering shape portion having a meandering shape. Here, an example is shown in which the redundant portion 54 is composed of the wound shape portions 60A, 60B. The meandering shape portion will be described later. Alternatively, the redundant portion 54 may be composed of a combination of the wound shape portions 60A, 60B and the meandering shape portion, or may be embodied in other ways.

[0028] The redundant portion 54 of this embodiment includes a first wound portion 60A and a second wound portion 60B, but the number of the wound portions is not particularly limited. The wound portions 60A and 60B are repeatedly wound around a virtual winding center C60. The wound portions 60A and 60B of this embodiment are wound around core materials 62A and 62B, but the core materials 62A and 62B are not essential. The first wound portion 60A is wound around a first core material 62A, and the second wound portion 60B is wound around a second core material 62B different from the first core material 62A. The first core material 62A here is the liquid source holder 38, and the second core material 62B is a tube connection member 64 connected to the liquid source holder 38. Although not shown, the end of another tube 66 constituting the liquid flow path 16 is connected to this tube connection member 64.

[0029] The wound portions 60A and 60B in this embodiment are wound in a spiral shape, but may be wound in a vortex shape. In the spiral winding, the first wound portion 60A in this embodiment is a shape in which a plurality of spiral portions 68 each having a spiral wound shape are overlapped in the radial direction, but the number of the spiral portions 68 is not particularly limited. Either a part of the liquid source 12 or the liquid flow path 16 may be provided inside the wound portions 60A and 60B. In this embodiment, the liquid source 12 is provided inside the first wound portion 60A, and the upstream end of the liquid flow path 16 is provided inside the second wound portion 60B.

[0030] The redundant portion 54 of the tube 52 may be at least twice as long as the shortest distance L1 (see FIG. 2) between the first connecting member 56 and the second connecting member 58, for example, in order to provide a margin in length. The redundant portion 54 may be, for example, 10 times or more, or 20 times or more, longer than the shortest distance L1. In addition, the redundant portion 54 of the tube 52 is larger than the maximum outer dimension L2 of the casing 32 in a plan view in order to provide a margin in length. The maximum outer dimension L2 here refers to the maximum outer dimension of the casing 32. The maximum outer dimension L2 in this embodiment is the outer dimension from the outer surface of one corner 32a on the diagonal line of the casing 32 to the outer surface of the other corner 32b. The redundant portion 54 may be 5 times or more, or 10 times or more longer than the maximum outer dimension L2. The length of the redundant portion 54 may be longer than the length of the portion of the flow path 16 from the detection portion 42 to the second connecting member 58 other than the redundant portion 54. This "portion other than the redundant portion 54" refers to the combination of the flow path portion from the detection portion 42 to the second connecting member 58, the flow path portion upstream of the redundant portion 54, and the flow path portion downstream of the redundant portion 54.

[0031] The effects of the above liquid supply system 10 will now be described.

[0032] The liquid supply system 10 includes a buffer section 50 that is provided in the liquid flow path 16 and can temporarily store liquid even after the liquid shortage detector 20 detects that the liquid is out of the liquid. Therefore, when the liquid supply unit 18 continues to send liquid even after the liquid shortage detector 20 detects that the liquid is out of the liquid, the liquid in the buffer section 50 can be sent to the liquid use point 14 for a while. This makes it possible to delay the time until the liquid supply is impossible and the liquid cannot be supplied to the liquid use point 14 after the liquid shortage detector 20 detects that the liquid is out of the liquid, compared to when the buffer section 50 is not provided. As a result, even if there is a delay in obtaining either a new liquid source 12 or the liquid, the liquid can be used at the liquid use point 14 for as long as possible.

[0033] When the buffer unit 50 is configured with a tank, it is difficult to use up as much liquid as possible in the tank unless the tank outlet is positioned lower than the storage chamber in the tank. When the liquid in the tank is sent by suction of the liquid sending unit 18, consider a case where the tank outlet is positioned lower than the storage chamber. In this case, the liquid supplied from the liquid source 12 side to the tank is sucked into the liquid sending unit 18 side by suction without being stored in the tank, making it difficult to increase the amount of liquid stored in the tank. In other words, when the buffer unit 50 is configured with a tank, there is a problem that it is difficult to increase the amount of liquid stored while using up as much liquid as possible in the tank.

[0034] In this regard, the buffer section 50 of the present embodiment is configured with a redundant section 54 provided in the tube 52. Therefore, the liquid in the redundant section 54 of the tube 52 can be easily sent downstream, making it easier to use up the liquid in the buffer section 50. Also, simply by increasing the length of the redundant section 54 of the tube, the amount of liquid stored in the buffer section 50 can be easily increased. Therefore, compared to when the buffer section 50 is configured with a tank, it is easier to increase the amount of liquid stored in the buffer section 50 while using up the liquid in the buffer section 50.

[0035] The redundant portion 54 is formed by the wound portions 60A and 60B. Therefore, compared to when the redundant portion 54 of the tube 52 is extended in a straight line, the overall size of the redundant portion 54 can be made compact while still increasing the length of the redundant portion 54. A similar effect can be obtained when the redundant portion 54 is formed by a meandering portion.

[0036] The liquid shortage detector 20 detects when the liquid source 12 is out of liquid based on the presence or absence of liquid in the detection target portion 42 of the liquid flow path 16. Therefore, when detecting when the liquid source 12 is out of liquid, it is possible to detect when the liquid source 12 is out of liquid without being affected by errors, compared to when the usage period from when the liquid source 12 started to be used, as well as the integrated flow rate of the liquid supplied from the liquid source 12, is used. Furthermore, when a float switch is disposed in the liquid source 12 to detect when the liquid source 12 is out of liquid, it is necessary to set the drain direction for discharging the liquid from the liquid source 12 downward in order to use up the liquid in the liquid source 12. In this regard, since it is possible to detect when the liquid source 12 is out of liquid without disposing a float switch in the liquid source 12, the above-mentioned restriction on the drain direction of the liquid source 12 can be relaxed.

[0037] Next, other features of the liquid supply system 10 will be described. Please refer to FIG. 4. Here, a part of a cross section of the wound shape portion 60A of the tube 52 as viewed from the axial direction is shown on the right side of the figure, and the AA cross section shown on the right side is shown on the left side of the figure. Here, only a spiral portion of approximately one turn of the wound shape portion 60A formed by the redundant portion 54 is shown. The redundant portion 54 of this embodiment has a shape in which an upward flow path portion 70 that rises toward the flow direction of the tube 52 and a downward flow path portion 72 that descends toward the flow direction of the tube 52 are repeated. An upwardly convex mountain portion 74 is provided between the upward flow path portion 70 and the downward flow path portion 72.

[0038] As a result of further investigation into providing the redundant portion 54 in the tube 52, the inventors of the present application came to the following new realization. When providing the redundant portion 54 in the tube 52, it seems desirable to increase the inner diameter D52 of the tube 52 from the viewpoint of increasing the amount of liquid stored as much as possible. However, if the inner diameter of the redundant portion 54 of the tube 52 is increased, an overtaking phenomenon in which the air bubbles 76 overtake the liquid 78 in the upward flow passage portion 70 of the redundant portion 54 of the tube 52 is likely to occur. This can be assumed to be due to the following reasons.

[0039] In the upward flow passage section 70, when the surface tension acting on the bubble 76 at the contact point between the inner wall surface of the tube 52 and the bubble 76 is greater than the buoyancy acting on the bubble 76, the bubble 76 does not rise up and remains in the upward flow passage section 70. As shown in FIG. 4, when the bubble 76 becomes larger in a cross section perpendicular to the flow direction of the tube 52 (hereinafter referred to as a tube cross section), the buoyancy acting on the bubble 76 becomes greater. When the buoyancy becomes greater than the surface tension acting on the bubble 76, the bubble 76 peels off the inner wall surface of the tube 52 and rises up to the peak portion 74, which causes the above-mentioned overtaking phenomenon. Here, as shown in FIG. 5, when the inner diameter D52 of the tube 52 is small, even if the bubble 76 gathers and grows, the bubble 76 hits both radial sides of the inner wall surface of the tube 52 before it rises up, making it easier to maintain a state in which the surface tension is greater than the buoyancy. As a result, the overtaking phenomenon is less likely to occur. 4, when the inner diameter D52 of the tube 52 is large, the buoyancy tends to become greater than the surface tension before the bubble 76 grows to the point where it hits both radial sides of the inner wall surface of the tube 52. As a result, the overtaking phenomenon tends to occur.

[0040] When such an overtaking phenomenon occurs in the upward flow passage section 70 of the tube 52, the air bubbles 76 move preferentially downstream while the liquid 78 remains in the upward flow passage section 70. The air bubbles 76 remain as a mass of gas 80 in the peak section 74 of the tube 52, and some of them move further downstream, and in the process, move downstream again due to the overtaking phenomenon in the upward flow passage section 70 that exists. As a result, due to the overtaking phenomenon, a problem may occur in which only gas is supplied from the liquid flow passage 16 to the liquid use point 14 while the liquid 78 in the upward flow passage section 70 remains in a state without being effectively used. This overtaking phenomenon and the problems caused by it occur when the gas in the gas reservoir 48 starts to flow through the liquid flow passage 16 after the liquid source 12 runs out of liquid.

[0041] The inventors of the present application have come to the realization that, from the viewpoint of suppressing such an overtaking phenomenon in the upward flow passage portion 70 of the tube 52, it is effective to reduce the inner diameter D52 of the redundant portion 54 of the tube 52 to a certain extent, although this goes against the objective of increasing the amount of liquid stored. This is because, as described above, this makes it easier to maintain a state in the upward flow passage portion 70 where the surface tension is greater than the buoyancy acting on the air bubbles 76. Suppressing this overtaking phenomenon can be advantageous in solving the problem that only gas is supplied from the liquid flow passage 16 to the liquid-using portion 14 while the liquid 78 remains in the upward flow passage portion 70.

[0042] From the viewpoint of suppressing the overtaking phenomenon of the tube 52 in the upward flow passage section 70, the inner diameter D52 of the tube 52 in the redundant section 54 is preferably 3.5 mm or less. Here, the inner diameter D52 refers to a diameter. This is advantageous in suppressing the overtaking phenomenon of the tube 52 in the upward flow passage section 70, compared with a case where the inner diameter D52 of the tube 52 is somewhat larger than this (for example, 5.0 mm). This condition of the inner diameter D52 of the tube 52 specifies that the inner diameter of the tube 52 should be made small to a certain extent from the viewpoint of suppressing the overtaking phenomenon of the tube 52 in the upward flow passage section 70, using a numerical value as a guideline, and the numerical value does not have a critical meaning. The lower limit of the inner diameter of the tube 52 is not particularly limited, but may be, for example, 0.5 mm or more in consideration of a size that can be actually realized.

[0043] In the above, the problem of the overtaking phenomenon being likely to occur in the ascending flow path portion 70 of the tube 52 has been described. This problem is likely to occur in an environment where the amount of liquid sent per unit time from the liquid sending portion 18 is small, such as 10.0 (mL / min) or less. When the liquid in the liquid flow path 16 is added to the main flow path 26 as in this embodiment, the instantaneous flow rate of the liquid in the main flow path 26 is, for example, 1.0 (L / min) or more. It can also be said that the above problem is likely to occur when the amount of liquid sent from the liquid sending portion 18 is very small compared to the instantaneous flow rate of the liquid in the main flow path 26.

[0044] The amount of liquid delivered per unit time of the liquid delivery unit 18 of this embodiment is preferably 10.0 (mL / min) or less as described here. This is advantageous in solving the problem by satisfying the above-mentioned condition of the inner diameter of the tube 52 even under the condition of the amount of liquid delivered that is likely to cause the overtaking phenomenon in the ascending flow path portion 70 of the tube 52. The reason for making the amount of liquid delivered small in this way is that the amount of liquid required at the liquid use portion 14 is small. The amount of liquid delivered by the liquid delivery unit 18 here is adjusted to this range by adopting a liquid delivery unit 18 with a small maximum amount of liquid delivered and controlling the amount of liquid delivered by the liquid delivery unit 18 with the control unit 22. The lower limit of the amount of liquid delivered by the liquid delivery unit 18 is not particularly limited, but may be, for example, 0.5 (mL / min) or more.

[0045] The inventor of the present application has set the above-mentioned numerical range for the inner diameter of the tube 52 as a result of various experiments. An example of an experiment on which this is based will be described. This experiment was conducted under conditions in which the inner diameter of the tube 52 was changed in various ways, and a small amount of gas was sent into the tube 52 while a liquid was passed through the tube 52, in order to confirm whether or not an overtaking phenomenon occurs in the ascending flow passage portion 70 of the tube 52. The tube 52 used was equipped with an ascending flow passage portion 70 and a descending flow passage portion 72 as shown in Figs. 4 and 5. The fluid in the tube 52 was sucked by the liquid sending portion 18. The liquid sending amount of the liquid sending portion 18 was 1.5 (mL / min) and 3.0 (mL / min). The liquid sending portion 18 was operated so as to intermittently repeat the suction operation. When the liquid sending portion 18 stopped the suction operation, it was evaluated that the overtaking phenomenon occurred when the air bubble 76 did not stop in the middle of the ascending flow passage portion 70 of the tube 52 and rose to the peak portion 74 as shown in Fig. 4. In contrast, when the bubble 76 remains stopped midway through the ascending flow path portion 70 of the tube 52 as shown in Fig. 5, it is evaluated that the overtaking phenomenon does not occur. Table 1 shows the relationship between the inner diameter of the tube 52 and the overtaking phenomenon. As described above, when the inner diameter of the tube 52 is 3.5 mm or less, the overtaking phenomenon does not occur, and it can be seen that in relation to the overtaking phenomenon, it is effective to reduce the inner diameter of the tube 52.

[0046] [Table 1]

[0047] (Second embodiment) Please refer to FIG. 6. In this embodiment, an example will be described in which the redundant portion 54 of the tube 52 is constituted by a serpentine portion 90. The serpentine portion 90 has a serpentine shape that moves repeatedly back and forth in a first direction X and moves in a second direction Y perpendicular to the first direction X as a whole. The serpentine portion 90 includes a plurality of extension portions 92 that extend in the first direction X and are spaced apart in the second direction Y, and a plurality of foldback portions 94 that connect the first direction ends of adjacent extension portions 92. The number of foldbacks of the serpentine portion 90 is not particularly limited, but may be, for example, two, three, four or more. In this embodiment, the same effect as that of the liquid supply system 10 of the first embodiment can be obtained.

[0048] Next, variations of each of the components described above will be described.

[0049] The liquid shortage detector 20 may be a float switch provided in the liquid source 12 and detecting a liquid shortage when the amount of water falls below a specified level. There are no particular limitations on the specific example of how the liquid supply system 10 is configured to allow gas to flow through the liquid flow path 16 when the liquid source 12 runs out of liquid. For example, this may be achieved by using an open tank as the liquid source 12.

[0050] The above-mentioned embodiment and modified forms are merely examples. The technical ideas abstracted from these should not be interpreted as being limited to the contents of the embodiment and modified forms. The contents of the embodiment and modified forms may be modified in many ways, such as changing, adding, or deleting components. In the above-mentioned embodiment, the contents in which such design changes are possible are emphasized by adding the notation "embodiment". However, design changes are also permitted even in contents without such notation.

[0051] When the technical ideas embodied in the above-described embodiments and modified forms are generalized, it can be said that the technical ideas described in the following items are included.

[0052] (2) The liquid supply system according to the 1st item, wherein the buffer section is constituted by a redundant section provided in a tube that constitutes the liquid flow path.

[0053] (3) The liquid supply system according to the 2nd item, wherein the redundant portion is constituted by at least one of a winding portion having a winding shape and a serpentine portion having a serpentine shape.

[0054] (4th item) The liquid supply system according to either of the second and third items, wherein the inner diameter of the tube in the redundant portion is 3.5 (mm) or less.

[0055] (Item 5) A liquid supply system according to item 4, wherein the amount of liquid delivered per unit time by the liquid delivery section is 10.0 (mL / min) or less.

[0056] (Item 6) The liquid supply system according to any one of Items 1 to 5, wherein the liquid shortage detector detects the liquid shortage in the liquid source based on the presence or absence of liquid in a detection target portion of the liquid flow path.

[0057] (Item 7) A liquid supply system described in any one of items 1 to 6, wherein the liquid flow path directly supplies liquid to the liquid usage location, and the liquid usage location is either a main flow path through which other liquid flows, or an ejection device. [Explanation of symbols]

[0058] 10...liquid supply system, 12...liquid source, 14...liquid usage point, 16...liquid flow path, 18...liquid delivery section, 20...liquid shortage detector, 26...main flow path, 36...discharge device, 42...detected section, 50...buffer section, 52...tube, 54...redundant section, 60A, 60B...wound section, 90...serpentine section.

Claims

1. A liquid flow path for supplying a liquid supplied from a liquid source to a liquid use point; a liquid delivery section capable of delivering the liquid in the liquid flow path to the liquid use location; A liquid shortage detector capable of detecting the liquid shortage of the liquid source; a buffer section provided in the liquid flow path and capable of temporarily storing liquid even after the liquid shortage detector detects a shortage of liquid.

2. 2. The liquid supply system according to claim 1, wherein the buffer portion is constituted by a redundant portion provided in a tube that constitutes the liquid flow path.

3. 3. The liquid supply system according to claim 2, wherein the redundant portion is configured by at least one of a winding portion having a wound shape and a serpentine portion having a serpentine shape.

4. 3. The liquid supply system according to claim 2, wherein the inner diameter of the tube in the redundant portion is 3.5 mm or less.

5. The liquid supply system according to claim 4 , wherein the liquid delivery section delivers a liquid amount per unit time of 10.0 (mL / min) or less.

6. The liquid supply system according to claim 1 , wherein the liquid shortage detector detects the liquid shortage in the liquid source based on the presence or absence of liquid in a detection portion of the liquid flow path.

7. The liquid flow path supplies liquid directly to the liquid use point, 2. The liquid supply system according to claim 1, wherein the liquid use location is either a main flow path through which other liquid flows, or a discharge device.

Images