Filter assemblies and filtration systems

Abstract

To provide a technology for allowing a user to use a filter assembly to grasp occurrences of abnormalities in drawing a liquid into the downstream side.SOLUTION: A filter assembly includes: a housing 50 having a fixing member 58 and a movable member 60 which may be detachably attached to the fixing member 58 and cooperates with the fixing member 58 to form an inner chamber 52; and a filter cartridge 54 housed in the inner chamber 52. The housing 50 and the filter cartridge 54 form an inner passage 30 forming part of a liquid passage, in which a liquid flows, and going through the filter 74 incorporated into the filter cartridge 54. The inner passage 30 is provided with an air reservoir 154 in which air is enclosed by the liquid accumulated in the inner passage 30.SELECTED DRAWING: Figure 9

Description

Technical Field

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[0001] The present disclosure relates to a filter assembly used in a filtration system.

Background Art

[0002] Patent Document 1 discloses a filter assembly using a filter cartridge for filtering a liquid. This filter assembly includes a housing having a fixed member and a movable member detachably attached to the fixed member, and a filter cartridge housed in an inner chamber formed by the cooperation of the fixed member and the movable member. The housing and the filter cartridge form a part of a liquid flow path through which the liquid flows, and an internal flow path passing through a filter built into the filter cartridge.

Prior Art Documents

[0007] [Figure 1] This is a schematic overall diagram of the filtration system according to the first embodiment. [Figure 2] This is a perspective view of the filter unit according to the first embodiment. [Figure 3] This is a front view of the filter unit according to the first embodiment. [Figure 4] This is a side cross-sectional view of the filter assembly according to the first embodiment. [Figure 5] This is an exploded view of the filter assembly, seen from the same viewpoint as Figure 4. [Figure 6] This is a view of the filter assembly from the direction of arrow A in Figure 4. [Figure 7] This is an enlarged view of Figure 4. [Figure 8] Figure 4 is a cross-sectional view of CC. [Figure 9] This figure shows the state of liquid accumulating inside the filter assembly shown in Figure 4. [Figure 10A] This is a first explanatory diagram of the retraction abnormality in the first embodiment. [Figure 10B] This is a second explanatory diagram of the retraction abnormality in the first embodiment. [Figure 11] This is a side cross-sectional view of the filter assembly according to the second embodiment. [Figure 12A] This is the first explanatory diagram of the air venting method of the second embodiment. [Figure 12B] This is a second explanatory diagram of the air venting method according to the second embodiment. [Figure 12C]This is a third explanatory diagram of the air venting method of the second embodiment. [Figure 13] This is a side cross-sectional view of the filter assembly according to the third embodiment. [Modes for carrying out the invention]

[0008] Embodiments for implementing the filtration system of this disclosure are described below. The same reference numerals are used for identical components, and redundant descriptions are omitted. For the sake of clarity, components are omitted, enlarged, or reduced in each drawing. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0009] (First Embodiment) Refer to Figure 1. The filtration system 10 is used to filter a liquid by a filter assembly 12. The filtration system 10 includes a liquid channel 14 through which liquid flows, a liquid source 16 that supplies liquid to the liquid channel 14, a filter assembly 12 provided in the liquid channel 14, a liquid delivery unit 18 provided downstream of the filter assembly 12 in the liquid channel 14, and a control unit 20 that controls the operation of the filtration system 10. In addition, the filtration system 10 of this embodiment includes a water supply channel 22 through which raw water for diluting the filtered liquid supplied from the liquid channel 14 flows, a modification cartridge 24 provided in the water supply channel 22, and an on-off valve 26 provided in the water supply channel 22. The on-off valve 26 is, for example, an automatic on-off valve such as a solenoid valve or an electric valve.

[0010] The liquid channel 14 supplies the liquid filtered by the filter assembly 12 to the liquid-supplied section 28. In this embodiment, an example is described in which the liquid-supplied section 28 is the water supply channel 22. The liquid channel 14 comprises an internal channel 30 provided inside the filter assembly 12, a primary channel 32 provided upstream of the internal channel 30, and a secondary channel 34 provided downstream of the internal channel 30.

[0011] The liquid source 16 uses, for example, a sealed container that can be reduced in volume and deformed by suction by the liquid delivery unit 18. The liquid source 16 using this sealed container can be deformed (i.e., reduced in volume and deformed) so that its volume decreases with the decrease of the liquid by suction by the liquid delivery unit 18. In addition to this, the liquid source 16 may be, for example, various containers and various tanks (such as open tanks).

[0012] The liquid source 16 is detachable from a liquid source holder (not shown). The liquid is used for drinking, such as, for example, diluting beverage liquid, food additive concentrate, seasoning liquid, etc. In addition to this, the liquid may be used for applications that touch the human body, such as soap water, lotion, body oil, etc. The applications that touch the human body include the diluting beverage liquid, etc. used for the aforementioned drinking. In addition to this, the liquid may be water such as tap water.

[0013] The liquid delivery unit 18 applies a negative pressure that draws in the liquid delivery unit 18 side on the upstream side of the liquid delivery unit 18 of the liquid flow path 14. The liquid delivery unit 18 delivers the liquid by discharging the liquid drawn in from the liquid source 16 side toward the liquid receiving unit 28 side. The liquid delivery unit 18 of the present embodiment delivers the liquid by being driven by the driving power supplied from the control unit 20. The liquid delivery unit 18 of the present embodiment includes, in addition to the pump, a motor that drives the pump. In addition to this, the liquid delivery unit 18 may include, for example, in addition to the pump, a solenoid that drives the pump. The pump of the liquid delivery unit 18 of the present embodiment is a tube pump, but in addition to this, various pumps such as gear pumps, vane pumps, metering pumps, etc. may be adopted. The specific example of the liquid delivery unit 18 is not particularly limited, and it may be, for example, a compressor or the like. The liquid delivery unit 18 of the present embodiment operates with a power supply, but it may also operate without a power supply. In this case, the liquid delivery unit 18 may be, for example, a water flow-driven pump that is driven using the flow of water flowing through the water supply flow path 22.

[0014] Raw water is supplied to the water supply passage 22 from a water source (not shown) on the upstream side. At the confluence 36 with the liquid flow passage 14, the water supply passage 22 generates dilution water by diluting the liquid supplied from the liquid flow passage 14 with the raw water, and supplies the generated dilution water to the water supply target portion 38. The water supply target portion 38 of the present embodiment is the water discharge portion of a water discharge device that discharges dilution water. Here, a water discharge pipe is shown as an example of the water discharge device. In addition to this, the water discharge device may be, for example, a shower head or the like. Here, an example of supplying dilution water as drinking water to the water supply target portion 38 will be described. The "raw water" here refers to the solvent to be added to the liquid supplied from the filtration system 10. Whether the "raw water" is reformed by passing through the reforming cartridge 24 is not a concern. The raw water may be tap water containing a chlorine component, natural water, or the like.

[0015] A part of the water supply passage 22 is provided inside the reforming cartridge 24 itself, and the raw water flowing through its own interior can be reformed. The "reforming" here refers to either removing specific components from the raw water or adding them to the raw water through either a physical change or a chemical change. The reforming cartridge 24 of the present embodiment is a water purification cartridge that removes the chlorine component contained in the tap water flowing in as raw water, and generates purified water by purifying the raw water. In addition to this, as a reforming mode of the raw water, beauty components, fragrance components, carbonic acid components, hydrogen components, etc. may be added to the raw water. The reforming cartridge 24 is detachable from a cartridge holder (not shown).

[0016] The control unit 20 is, for example, a microcomputer, and is composed of a combination of a CPU, ROM, RAM, etc. The control unit 20 can control the liquid supply operation of the liquid supply unit 18. The control unit 20 in this embodiment can also control the opening and closing operation of the on-off valve 26. The control unit 20 performs a liquid supply operation by starting the liquid supply operation of the liquid supply unit 18, thereby supplying liquid to the liquid-receiving unit 28. As a result, liquid flows through the liquid channel 14 by the liquid supply unit 18, and the liquid filtered by the filter assembly 12 is supplied to the liquid-receiving unit 28. The liquid supply operation in this embodiment is performed by starting the liquid supply operation of the liquid supply unit 18 and opening the on-off valve 26 to allow raw water to flow through the water supply channel 22. As a result, the liquid filtered from the liquid channel 14 is supplied to the raw water flowing through the water supply channel 22, generating diluted water, which is then supplied to the liquid-receiving unit 38 via the water supply channel 22.

[0017] Refer to Figures 1, 2, and 3. The filtration system 10 includes a filter unit 40 incorporating a filter assembly 12. In addition to the filter assembly 12, the filter unit 40 includes the aforementioned liquid source 16, internal flow path 30, liquid delivery unit 18, reforming cartridge 24, and a housing 42 that houses these components. The housing 42 is installed on a base 44 such as a kitchen cabinet.

[0018] Refer to Figures 4 and 5. The filter assembly 12 mainly comprises a housing 50 and a filter cartridge 54 housed in an inner chamber 52 formed in the housing 50. The filter assembly 12 is characterized by two main features: a first feature relating to the first sealing member 56, which will be described later, and a second feature relating to an air pocket (not shown). The following describes the basic configuration of the filter assembly 12, and then explains each feature individually.

[0019] The housing 50 comprises a fixed member 58 and a movable member 60 that can be attached to and detached from the fixed member 58 by movement in the attachment / detachment direction Da. Here, the attachment / detachment direction Da refers to a combination of two movement directions (attachment direction Da1 and removal direction Da2) of the movable member 60 when attaching or detaching it from the fixed member 58. One side of the attachment / detachment direction Da is the attachment direction Da1, in which the movable member 60 approaches the fixed member 58 when attaching the movable member 60 to the fixed member 58. The other side of the attachment / detachment direction Da is the removal direction Da2, in which the movable member 60 moves away from the fixed member 58 when removing the movable member 60 from the fixed member 58. The fixed member 58 and the movable member 60 are made of resin, metal, etc. Here, an example is shown in which they are resin molded products obtained by injection molding or the like.

[0020] Refer to Figure 6. Figure 4 is also a cross-sectional view of BB in Figure 6. The fixing member 58 includes a fixing portion 66 which is fixed to an external fixed member 64 by a first fixing device 62 such as a screw member. The fixed member 64 is, for example, a housing 42 that houses the filter assembly 12.

[0021] Refer to Figures 4 and 5. The fixing member 58 comprises a bottomed cylindrical inner portion 58a and a bottomed cylindrical outer portion 58b surrounding the inner portion 58a. The inner portion 58a forms a central recess 58c that is recessed in the mounting direction Da1, and a first opening 58d is provided at its tip in the removal direction Da2. The outer portion 58b forms an annular recess 58e between itself and the inner portion 58a that is recessed in the mounting direction Da1.

[0022] The movable member 60 as a whole has a bottomed cylindrical shape that is recessed in the removal direction Da2. A second opening 60a is provided at the tip of the movable member 60 in the mounting direction Da1. The tip portion of the movable member 60 is inserted into the annular recess 58e of the fixed member 58. The movable member 60 cooperates with the fixed member 58 to form an inner chamber 52. In this embodiment, the inner chamber 52 is formed by the central recess 58c and annular recess 58e of the fixed member 58 and the movable member 60. A second sealing member 68, such as an O-ring, is placed between the movable member 60 and the fixed member 58 to seal the space between them. The second sealing member 68 prevents fluid flow between the external space 70 outside the filter assembly 12 and the inner chamber 52. The second sealing member 68 is placed between the inner circumference of the outer cylindrical portion 58b of the fixed member 58 and the outer circumference of the movable member 60.

[0023] The movable member 60 is detachable from the fixed member 58 by the first attachment / detachment structure 72. The first attachment / detachment structure 72 in this embodiment is a screw structure and comprises a female screw portion 72a provided on the fixed member 58 and a male screw portion 72b provided on the movable member 60. The female screw portion 72a is provided on the inner circumference of the outer cylindrical portion 58b of the fixed member 58, and the male screw portion 72b is provided on the outer circumference of the movable member 60. The specific example of the first attachment / detachment structure 72 is not particularly limited and may be implemented using snap-fit, interlocking, magnetism, etc.

[0024] The movable member 60 comprises a large inner diameter portion 60b provided on the tip side of the movable member 60, a small inner diameter portion 60c provided on the bottom side of the movable member 60 relative to the large inner diameter portion 60b, and a tapered portion 60d provided between the large inner diameter portion 60b and the small inner diameter portion 60c. The small inner diameter portion 60c has a smaller inner diameter than the large inner diameter portion 60b. The tapered portion 60d gradually reduces its inner diameter from the large inner diameter portion 60b towards the small inner diameter portion 60c.

[0025] The movable member 60 is provided with a cartridge receiving portion 60e at its bottom to receive the filter cartridge 54. In this embodiment, the cartridge receiving portion 60e is rib-shaped, protruding from the bottom of the movable member 60 toward the front and protruding radially inward from the filter cartridge 54, and is provided at intervals in the circumferential direction of the filter cartridge 54.

[0026] The movable member 60 is provided with a finger rest 60f for the user to place their fingers on when attaching or detaching the movable member 60 from the fixed member 58 (see also Figure 3). The finger rest 60f is a projection that extends radially outward from the outer circumference of the movable member 60. In this embodiment, the movable member 60 can be attached to and detached from the fixed member 58 by rotating it around the center line C54 of the filter cartridge 54 using the first attachment / detachment structure 72 (screw structure). The finger rest 60f in this embodiment is used to place fingers on when rotating the movable member 60 in this manner. Multiple finger rests 60f in this embodiment are provided at intervals in the circumferential direction of the filter cartridge 54 (two in this case).

[0027] The filter cartridge 54 is housed in the inner chamber 52 of the housing 50. The filter cartridge 54 can be inserted into or removed from either the inner chamber 52 of the fixed member 58 or the movable member 60 by removing the movable member 60 from the fixed member 58. In this embodiment, when the movable member 60 is removed from the fixed member 58, the filter cartridge 54 is maintained in the state attached by the movable member 60 by the elastic member 128 described later, and can be removed through the second opening 60a from the inner chamber 52 of the movable member 60. The filter cartridge 54 has a protruding portion 54a that protrudes toward the mounting direction Da1 side from the second opening 60a of the movable member 60. By gripping the protruding portion 54a of the filter cartridge 54, the operation of inserting and removing the filter cartridge 54 through the second opening 60a becomes easier.

[0028] The filter cartridge 54 as a whole has a columnar shape (cylindrical in this embodiment) extending along its own centerline C54. Hereinafter, the direction along the centerline C54 of the filter cartridge 54 will be referred to as the axial direction, and the radial and circumferential directions of the circle centered on that centerline will be referred to as the radial direction and circumferential direction, respectively. The axial direction of the filter cartridge 54 coincides with the attachment / detachment direction Da of the movable member 60 to the fixed member 58. Here, the centerline C54 of the filter cartridge 54 refers to the line drawn by connecting the geometric centers of the outer circumferential surface of the filter cartridge 54 in the longitudinal direction of the filter cartridge 54.

[0029] The filter cartridge 54 contains a filter 74 for filtering liquids. In addition to the filter 74, the filter cartridge 54 also includes a filter case 78 that has a filter chamber 76 for housing the filter 74.

[0030] The filter case 78 comprises a bottomed cylindrical case body 80 and a cap 82 that closes the inlet opening of the case body 80. The case body 80 comprises a cylindrical wall portion 80a and a bottom wall portion 80b provided at the axial end of the cylindrical wall portion 80a. The filter chamber 76 is formed in the area surrounded by the case body 80 and the cap 82.

[0031] The filter 74 filters the liquid by capturing foreign matter contained in the liquid as it passes through the internal flow path 30 of the filter assembly 12. The filter 74 in this embodiment also has the function of disinfecting the liquid by capturing microorganisms as foreign matter.

[0032] The filter 74 in this embodiment is a hollow fiber membrane filter. This filter 74 comprises a plurality of straw-shaped hollow fiber membranes 84. The plurality of hollow fiber membranes 84 are bundled together by a bundling member 86. In this embodiment, the bundling member 86 also serves as the cap 82 of the filter case 78. The plurality of hollow fiber membranes 84 in this embodiment are bent into a U-shape, and both ends are bundled together by the bundling member 86. The specific example of the filter 74 is not particularly limited, and various filters such as activated carbon filters and ceramic filters may be used.

[0033] The housing 50 and the filter cartridge 54 become part of the liquid flow path 14 and form an internal flow path 30 that passes through the filter 74. The internal flow path 30 comprises, in order from upstream to downstream, an inlet flow path 90, an upstream liquid chamber 92, an inlet hole 94, a filter chamber 76, an outlet hole 96, a downstream liquid chamber 98, and an outlet flow path 100.

[0034] The inlet channel 90 is formed in the fixing member 58 of the housing 50. The inlet channel 90 includes an inlet hole 90a that opens to the outer surface portion 58f of the fixing member 58, and a first communication hole 90b that connects the inlet hole 90a to the upstream liquid chamber 92. The primary channel member 102 is inserted into the inlet hole 90a and is watertightly attached by a third sealing member 104. The primary channel member 102 is fixed to the fixing member 58 by a second fixing device 106 such as a screw member. A flexible primary tube 108 (see Figure 6) is watertightly connected to the primary channel member 102. A portion of the primary channel 32 is provided inside the primary channel member 102 and the primary tube 108.

[0035] The upstream liquid chamber 92 and the downstream liquid chamber 98 are formed outside the filter cartridge 54 within the inner chamber 52 of the housing 50, as the filter cartridge 54 is housed in the inner chamber 52. In this embodiment, the upstream liquid chamber 92 is provided between the movable member 60 and the filter cartridge 54, as well as between the annular recess 58e of the fixed member 58 and the movable member 60. In this embodiment, the downstream liquid chamber 98 is formed between the central recess 58c of the fixed member 58 and the filter cartridge 54.

[0036] The filter cartridge 54 includes the aforementioned filter chamber 76, inlet hole 94, and outlet hole 96. The filter chamber 76 is formed inside the filter cartridge 54. The inlet hole 94 allows liquid to flow into the filter chamber 76 from the upstream liquid chamber 92, which is located upstream of the filter chamber 76 in the internal flow path 30. In this embodiment, the inlet hole 94 is provided in the bottom wall portion 80b of the case body 80 that constitutes the filter case 78. The outlet hole 96 allows liquid to flow out from the filter chamber 76 to the downstream liquid chamber 98, which is located downstream of the filter chamber 76 in the internal flow path 30. The outlet hole 96 is provided in the cap 82 that constitutes the filter case 78. In this embodiment, the outlet hole 96 also serves as the end of the hollow fiber membrane 84, and multiple outlet holes 96 are provided in the cap 82.

[0037] The outlet channel 100 is formed in the fixing member 58 of the housing 50. The outlet channel 100 includes an outlet hole 100a opening in the outer surface portion 58f of the fixing member 58, and a second communication hole 100b connecting the outlet hole 100a to the downstream liquid chamber 98. The secondary channel member 110 is inserted into the outlet hole 100a and is watertightly attached by a fourth sealing member 112. The secondary channel member 110 is fixed to the fixing member 58 by a third fixing device 114 (see Figure 6), such as a screw member. The secondary channel member 110 is connected to a flexible secondary tube 116. A portion of the secondary channel 34 is provided inside the secondary channel member 110 and the secondary tube 116. The inlet hole 90a and the outlet hole 100a open in the outer surface portion 58f of the fixing member 58 facing the same direction (in this case, the mounting direction Da1).

[0038] Liquid flows into the inlet channel 90 from the primary channel 32 of the liquid channel 14. The liquid that flows into the inlet channel 90 flows into the filter chamber 76 via the upstream liquid chamber 92 and the inlet hole 94. The liquid that flows into the filter chamber 76 flows out to the downstream liquid chamber 98 via the filter 74 and the outlet hole 96. The liquid that flows out to the downstream liquid chamber 98 flows out to the secondary channel 34 of the liquid channel 14 from the outlet channel 100. In this way, the liquid flowing through the liquid channel 14 is filtered as foreign matter contained in the liquid is captured by the filter 74.

[0039] Refer to Figure 7. The first improvement will be explained. The filter assembly 12 includes a first sealing member 56 that seals the space between the fixing member 58 and the filter cartridge 54 by being compressed in the attachment / detachment direction Da (axial direction). The first sealing member 56 prevents the flow of liquid between the upstream liquid chamber 92 and the downstream liquid chamber 98 formed within the inner chamber 52. The first sealing member 56 is an annular elastic member such as an O-ring or X-ring.

[0040] In this embodiment, the first sealing member 56 is mounted on a one-member member 120, which is one of the fixing member 58 and the filter cartridge 54. Here, we will describe an example where the one-member member 120 is the filter cartridge 54. This one-member member 120 includes a circumferential surface portion 120a on which the first sealing member 56 is mounted, and a first pressing surface 120b that presses the first sealing member 56 in the attachment / detachment direction Da. In this embodiment, the circumferential surface portion 120a is the outer circumferential surface portion of the filter cartridge 54. The first sealing member 56 is mounted in a first mounting groove 120c provided on the circumferential surface portion 120a of the one-member member 120. In this embodiment, the first mounting groove 120c is formed between a pair of first annular portions 120d and 120e that protrude radially from the circumferential surface portion 120a of the one-member member 120. The first pressing surface 120b is provided on one of the first annular portions 120d of the pair of first annular portions 120d and 120e. The protruding length L120d of one of the first annular portions 120d is greater than the protruding length L120e of the other first annular portion 120e, thereby providing a first pressing surface 120b on the first annular portion 120d. Here, the protruding lengths L120d and 120e refer to the radial lengths from the circumferential surface portion 120a to the tip portion of one of the members 120.

[0041] The other member 122 (here, the fixing member 58), which is the other of the fixing member 58 and the filter cartridge 54, is provided with a second pressing surface 122a that presses the first sealing member 56 in the attachment / detachment direction Da. The second pressing surface 122a is provided at a position opposite the first pressing surface 120b in the attachment / detachment direction Da. In this embodiment, the second pressing surface 122a is provided at the tip of the inner cylindrical portion 58a of the fixing member 58. The second pressing surface 122a has a tapered shape so that it moves away from the circumferential surface portion 120a of the one member 120 as it approaches the first pressing surface 120b side. As a result, when pressing the first sealing member 56 between the first pressing surface 120b and the first sealing member 56, the first sealing member 56 can be pressed against the circumferential surface portion 120a of the one member 120, thereby making the first sealing member 56 tightly adhere to the circumferential surface portion 120a. Ultimately, this improves the sealing performance of the first sealing member 56.

[0042] The filter assembly 12 includes a second attachment / detachment structure 126 that allows the filter cartridge 54 to be attached to and detached from the movable member 60. The second attachment / detachment structure 126 in this embodiment is an elastic member 128 that is compressed radially between the movable member 60 and the filter cartridge 54. The elastic member 128 in this embodiment is an annular member such as an O-ring or X-ring. The second attachment / detachment structure 126 maintains the state in which the filter cartridge 54 is attached to the movable member 60 when the movable member 60 is removed from the fixed member 58 (see Figure 5). The second attachment / detachment structure 126 (elastic member 128) in this embodiment maintains the state in which the filter cartridge 54 is attached to the movable member 60 by the elastic restoring force caused by the compression of the elastic member 128.

[0043] The elastic member 128 is mounted in a second mounting groove 130 provided in either the filter cartridge 54 or the movable member 60 (in this case, the filter cartridge 54). In this embodiment, the second mounting groove 130 is formed between a pair of second annular portions 132 that protrude radially from the filter cartridge 54.

[0044] The elastic member 128 is positioned between the small inner diameter portion 60c of the movable member 60 and the filter cartridge 54. When the filter cartridge 54 is inserted into or removed from the second opening 60a of the movable member 60, the elastic member 128, which is attached to the filter cartridge 54, slides along the small inner diameter portion 60c without sliding along the large inner diameter portion 60b of the movable member 60. At this time, by sliding the elastic member 128 along the tapered portion 60d of the movable member 60, the elastic member 128 can be smoothly inserted into the small inner diameter portion 60c of the movable member 60.

[0045] In this embodiment, the filter cartridge 54 is removed from the movable member 60 by pulling it out through the second opening 60a (see Figure 5) of the movable member 60 against the elastic restoring force of the elastic member 128. The filter cartridge 54 is attached to the movable member 60 by the elastic member 128 by pushing it inward through the second opening 60a of the movable member 60 against the elastic restoring force of the elastic member 128. In this way, the second attachment / detachment structure 126 makes it possible to attach and detach the filter cartridge 54 to the movable member 60 by moving the filter cartridge 54 relative to the movable member 60.

[0046] The method for replacing the filter cartridge 54 using the filter assembly 12 described above will now be explained. First, the movable member 60 is removed from the fixed member 58 by moving the movable member 60 in the removal direction Da2 relative to the fixed member 58. In this embodiment, the movable member 60 is removed from the fixed member 58 by the first attachment / detachment structure 72 (screw structure) by rotating the movable member 60.

[0047] Next, the used filter cartridge 54 is replaced with a new filter cartridge 54. At this time, the used filter cartridge 54 is removed from the inner chamber 52 of either the fixed member 58 or the movable member 60 (in this case, the movable member 60), and then the new filter cartridge 54 is inserted into the same inner chamber 52.

[0048] Subsequently, the movable member 60 is attached to the fixed member 58 by moving the movable member 60 in the mounting direction Da1 relative to the fixed member 58. In this embodiment, the movable member 60 is attached to the fixed member 58 by the second attachment / detachment structure 126 (screw structure) by rotating the movable member 60. During this process, the first seal member 56 is pressed between the pressing surfaces 120b and 122a provided on the filter cartridge 54 and the movable member 60, respectively, and the first seal member 56 is crushed in the attachment / detachment direction Da. At this time, the cartridge receiving portion 60e of the movable member 60 presses the filter cartridge 54 in the mounting direction Da1, thereby crushing the first seal member 56 in the attachment / detachment direction Da.

[0049] The effects of the filter assembly 12 described above will now be explained.

[0050] (A) Let's consider the case where the first sealing member 56 is compressed radially between the fixing member 58 and the filter cartridge 54, perpendicular to the center line C54 of the filter cartridge 54. This refers to the case where the first sealing member 56 is compressed radially between the inner circumference of the inner cylindrical portion 58a of the fixing member 58 and the outer circumference of the filter cartridge 54. In this case, when the filter cartridge 54 is moved away from its fixed position in the filter assembly 12 in the removal direction Da2, the circumferential surface of the other member 122 (in this case, the fixing member 58) and the first sealing member 56 slide against each other until the first sealing member 56 is separated from the other member 122 (in this case, the fixing member 58) of the fixing member 58 and the filter cartridge 54. Similarly, when the filter cartridge 54 is brought closer to its fixed position in the mounting direction Da1, the circumferential surface of the other member 122 and the first sealing member 56 slide against each other until the filter cartridge 54 is positioned in its fixed position.

[0051] In this respect, the first sealing member 56 in this embodiment is compressed in the attachment / detachment direction Da between the fixing member 58 and the filter cartridge 54. Therefore, when the filter cartridge 54 is moved away from its fixed position in the removal direction Da2 from the fixed position in the filter assembly 12, the fixing member 58 and the other member 122 of the filter cartridge 54 and the first sealing member 56 hardly slide against each other. The same is true when the filter cartridge 54 is moved towards its fixed position in the mounting direction Da1. Consequently, compared to the case where the first sealing member 56 is compressed radially between the fixing member 58 and the filter cartridge 54, the sliding resistance acting on the first sealing member 56 when moving the filter cartridge 54 relative to the fixing member 58 in the attachment / detachment direction Da can be greatly reduced. This improves workability at that time. In addition, when the movable member 60 is removed from the fixing member 58, the elastic member 128 makes it easier to maintain the state in which the filter assembly 12 is attached to the movable member 60. Consequently, it becomes easier to avoid a situation where the filter cartridge 54 remains in the inner chamber 52 of the fixing member 58 due to the sliding resistance of the first sealing member 56.

[0052] The second attachment / detachment structure 126 maintains the state in which the filter cartridge 54 is attached to the movable member 60 when the movable member 60 is removed from the fixed member 58. Therefore, when removing the movable member 60 from the fixed member 58, the second attachment / detachment structure 126 allows the movable member 60 and the filter cartridge 54 to be handled as a single unit. This makes it possible to insert and remove the filter cartridge 54 into and out of the movable member 60 while holding the movable member 60 that has been removed from the fixed member 58. In turn, the replacement work of the filter cartridge 54 can be made easier.

[0053] The second detachable structure 126 is an elastic member 128 that is compressed between the movable member 60 and the filter cartridge 54. Therefore, the second detachable structure 126 can be realized with a simpler configuration compared to the case where the second detachable structure 126 is a screw structure. In particular, when a screw structure is provided, the difficulty of molding increases with the complexity of the mold when resin molding the movable member 60 and the filter cartridge 54. This has the advantage of being avoided.

[0054] Next, we will describe other features of the filter assembly 12.

[0055] The elastic member 128 divides the upstream liquid chamber 92 formed between the movable member 60 and the filter cartridge 54 into two small chambers 140A and 140B spaced apart in the attachment / detachment direction Da. Here, the small chambers 140A and 140B include a first small chamber 140A located on the attachment direction Da1 side of the elastic member 128, and a second small chamber 140B located on the removal direction Da2 side of the elastic member 128. The first small chamber 140A is mainly formed between the cylindrical wall portion 80a of the filter case 78 and the movable member 60. The second small chamber 140B is formed between the bottom wall portion 80b of the filter case 78 and the bottom of the movable member 60.

[0056] Refer to Figures 7 and 8. At least one of the movable member 60 and the filter cartridge 54 is provided with a communication channel 142 that connects two small chambers 140A and 140B. The two small chambers 140A and 140B and the communication channel 142 are provided as part of the internal channel 30. The communication channel 142 in this embodiment is grooves 142a and 142b provided at least on the inner circumferential surface of the movable member 60 that crushes the elastic member 128. The grooves 142a and 142b in this embodiment are provided at multiple (two in this case) positions spaced apart in the circumferential direction of the filter cartridge 54. These grooves 142a and 142b include an axial groove 142a provided along the attachment / detachment direction Da on the inner circumferential surface of the small inner diameter portion 60c of the movable member 60, and a radial groove 142b provided along the radial direction between adjacent cartridge receiving portions 60e.

[0057] As a result, even if the liquid chamber 92 formed between the movable member 60 and the filter cartridge 54 is divided into two small chambers 140A and 140B by the elastic member 128, liquid can be passed between the two small chambers 140A and 140B by the communication channel 142. Therefore, the movable member 60 and the filter cartridge 54 can be handled as a single unit by the elastic member 128, while liquid can be passed between the two small chambers 140A and 140B that are divided by the elastic member 128.

[0058] Furthermore, by making the communication channel 142 a groove, the communication channel 142 can be realized with a simpler configuration compared to the case where the communication channel 142 with a closed cross-section structure is formed by a single member. Here, a closed cross-section structure refers to a structure that forms a closed cross-section in a cross-section perpendicular to the channel axis.

[0059] In this embodiment, the axial groove 142a of the groove is provided in a position that overlaps radially with the finger grip portion 60f of the movable member 60 and the filter cartridge 54. This prevents a decrease in the appearance quality of the resin molded product (movable member 60) caused by uneven thickness at the location of the groove, compared to the case where the groove does not overlap radially with the finger grip portion 60f of the movable member 60.

[0060] Refer to Figure 9. The second point of improvement will now be explained. In this embodiment, the filter assembly 12 is installed in a sideways orientation, with the center line C54 of the filter cartridge 54 facing sideways. To achieve this, the housing 42 of the filter unit 40, including the filter assembly 12, is installed on the base 44 such that the center line C54 of the filter cartridge 54 faces sideways (see also Figures 3 and 4). Here, "sideways" includes not only the case where the center line C54 of the filter cartridge 54 is positioned parallel to the horizontal plane, but also the case where it is positioned approximately parallel to the horizontal plane. Unless otherwise specified, the positional relationships of each component when the filter cartridge 54 is positioned sideways in this embodiment will be explained below.

[0061] In this embodiment, the inlet passage 90 of the internal passage 30 is located above the center line C54 of the filter cartridge 54, and the outlet passage 100 of the internal passage 30 is located below the center line C54 of the filter cartridge 54. The outlet passage 100 is located below the inlet hole 94 of the filter cartridge 54. The secondary side passage member 110, which is attached to the outlet hole 100a of the outlet passage 100, is provided with an inlet portion 110a that is the upstream end of the secondary side passage 34. The bottom surface of the central recess 58c of the fixing member 58 is provided with a bottom recess 58g that is recessed in the mounting direction Da1 at the lower part of the bottom surface compared to the upper part of the bottom surface.

[0062] The internal flow path 30 is provided with a submerged portion 152 that is submerged below the liquid surface 150a of the liquid 150 stored in the internal flow path 30, thereby blocking the flow of air in the flow direction of the internal flow path 30. In this embodiment, the submerged portion 152 is provided in the outlet flow path 100 of the internal flow path 30. As a result, the internal flow path 30 is provided with an air reservoir 154 upstream of the submerged portion 152, where air is sealed in by the liquid 150 stored in the internal flow path 30. The air reservoir 154 is provided above the liquid surface 150a of the liquid 150 stored in the internal flow path 30. In this embodiment, the air reservoir 154 is provided in a part of the upstream liquid chamber 92, the filter chamber 76, and the downstream liquid chamber 98, which are located upstream of the outlet flow path 100 that becomes the submerged portion 152 of the internal flow path 30. It can also be said that the air reservoir 154 is provided at least upstream of the filter chamber 76 in the internal flow path 30.

[0063] By providing such an air reservoir 154 in the filter assembly 12, it becomes possible to detect when an abnormality occurs when drawing liquid from the internal flow path 30 downstream. This abnormality occurs, for example, when there is no liquid 150 left in the liquid source 16 that supplies liquid to the liquid flow path 14. In addition, an abnormality can occur when a blockage of foreign matter occurs upstream of the air reservoir 154 in the liquid flow path 14. An abnormality can also be said to occur when attempting to draw the liquid from the internal flow path 30 to the secondary flow path 34 while the inflow of liquid 150 from the primary flow path 32 to the internal flow path 30 is interrupted. The operation of the filter assembly 12 before and after the occurrence of this abnormality will be explained.

[0064] The liquid supply unit 18 (see Figure 1) applies negative pressure to draw the fluid in the internal flow path 30 downstream of the internal flow path 30 in the liquid flow path 14. When the liquid supply unit 18 applies negative pressure to the liquid flow path 14, drawing it towards the liquid supply unit 18, the liquid in the liquid source 16 is supplied to the liquid flow path 14 by this negative pressure. This liquid 150 flows from the primary flow path 32 of the liquid flow path 14 into the internal flow path 30 of the filter assembly 12. This liquid is then drawn from the internal flow path 30 to the secondary flow path 34. The flow direction Db of the liquid 150 in the internal flow path 30 is illustrated here.

[0065] Let's consider the case where there is no abnormality in the draw-in. In this case, the liquid 150 continues to flow through the internal flow path 30 of the filter assembly 12, with the submerged portion 152 of the internal flow path 30 remaining submerged below the liquid level 150a of the liquid 150 stored in the internal flow path 30. In other words, the liquid 150 continues to flow through the internal flow path 30 of the filter assembly 12, with air remaining in the air reservoir 154 within the internal flow path 30. In this normal state, the position of the liquid level 150a of the liquid 150 may differ depending on the part of the internal flow path 30. For example, the liquid level 150a in the downstream liquid chamber 98 may be lower than the liquid level 150a in the filter chamber 76. This occurs, for example, when the passage speed of the liquid 150 through the filter 74 is slower than the draw-in speed of the liquid 150 from the internal flow path 30 to the secondary flow path 34.

[0066] Refer to Figures 10A and 10B. Here, we show an example of how the state transitions from Figure 10A to Figure 10B as the entrapment abnormality progresses. When an entrapment abnormality occurs, the liquid in the internal flow path 30 is drawn into the secondary flow path 34 through the secondary flow path member 110, and the liquid level 150a of the liquid 150 that seals air in the air reservoir 154 gradually decreases in direction Dc. Consequently, the liquid in the submerged portion 152 of the internal flow path 30 is also drawn into the secondary flow path 34 through the secondary flow path member 110.

[0067] As shown in Figure 10B, the liquid 150 in the internal flow path 30 is drawn in by air until the area that would normally be an air reservoir 154 and the inlet 110a of the secondary flow path member 110 are connected by air through the area that would normally be submerged 152. When this connection is established, the air accumulated in the air reservoir 154 begins to be drawn in direction Dd towards the secondary flow path 34. As a result, air begins to flow through the secondary flow path 34 of the liquid flow path 14 upstream of the liquid delivery unit 18.

[0068] The effects of the filter assembly 12 regarding the second improvement described above will now be explained.

[0069] (B) Thus, the filter assembly 12 is equipped with the aforementioned air reservoir 154. Therefore, when an abnormality in drawing liquid downstream occurs in the internal flow path 30 of the liquid flow path 14, the air in the air reservoir 154 can be passed through the secondary flow path 34 of the liquid flow path 14 instead of the liquid 150. Consequently, as described later, the presence or absence of liquid in the secondary flow path 34 of the liquid flow path 14 can be detected to determine the occurrence of an abnormality in drawing liquid.

[0070] Refer to Figure 9. The inlet 94 of the filter cartridge 54 is provided in the bottom wall portion 80b of the case body 80. Therefore, compared to the case where the inlet 94 is provided in the cylindrical wall portion 80a of the case body 80, the inlet 94 can be positioned closer to the center line C54 of the filter cartridge 54, regardless of the variation in the circumferential position of the filter cartridge 54 relative to the housing 50. For example, if the inlet 94 is provided in the cylindrical wall portion 80a of the case body 80, depending on the circumferential position of the filter cartridge 54, the inlet 94 may be located at the upper end of the cylindrical wall portion 80a. In this case, the air reservoir 154 can only be provided above the upper end of the filter cartridge 54, and the amount of air that can be stored in the air reservoir 154 will be small.

[0071] In this respect, according to this embodiment, the inlet hole 94 can be positioned close to the center line C54 of the filter cartridge 54, regardless of fluctuations in the circumferential position of the filter cartridge 54. Therefore, a stable amount of air can be stored in the air reservoir 154 regardless of fluctuations in the circumferential position of the filter cartridge 54. In particular, the filter cartridge 54 of this embodiment is cylindrical, and the circumferential position of the filter cartridge 54 relative to the housing 50 can be adjusted. Even in such a case, there is the advantage of obtaining the effects described herein.

[0072] Furthermore, if the outlet passage 100 is located below the inlet hole 94 of the filter cartridge 54, under normal conditions, the liquid level 150a of the liquid 150 stored in the filter chamber 76 and downstream liquid chamber 98 of the filter cartridge 54 will be above the inlet hole 94 of the filter cartridge 54. Therefore, if the inlet hole 94 is provided in the cylindrical wall portion 80a of the case body 80, depending on the circumferential position of the filter cartridge 54 relative to the housing 50, the inlet hole 94 may be located at the lower end of the cylindrical wall portion 80a. In this case, the liquid level of the liquid 150 that can be stored in the filter chamber 76 and downstream liquid chamber 98 will be very low. Consequently, when the liquid 150 is flowing through the liquid passage 14 due to changes in the liquid level of the liquid 150, air in the air pockets 154 such as the filter chamber 76 will flow out into the secondary passage 34, making it easier for air to get trapped in the secondary passage 34.

[0073] In this respect, according to this embodiment, the inlet hole 94 can be positioned close to the center line C54 of the filter cartridge 54, regardless of fluctuations in the circumferential position of the filter cartridge 54. Therefore, regardless of fluctuations in the circumferential position of the filter cartridge 54, it becomes easier to secure the liquid level of the liquid 150 that can be stored in the filter chamber 76 and the downstream liquid chamber 98. Consequently, air in the air reservoir 154 such as the filter chamber 76 is less likely to flow out into the secondary flow path 34, and the risk of air entrapment in the secondary flow path 34 can be reduced.

[0074] In relation to ensuring a stable air volume and reducing the risk of air entrapment, as explained here, it is preferable that the inlet hole 94 of the filter cartridge 54 be located on the center line C54 of the filter cartridge 54.

[0075] The air reservoir 154 is provided at least upstream of the filter chamber 76 in the internal flow path 30. The advantages of this are explained below. Due to changes in the liquid level of the liquid 150 that seals the air in the air reservoir 154, air leaking from the air reservoir 154 may flow into the filter chamber 76. In this case, by providing the air reservoir 154 upstream of the filter chamber 76, it becomes easier to retain the air leaking from the air reservoir 154 in the filter cartridge 54 by the filter 74 in the filter chamber 76. Therefore, compared to the case where the air reservoir 154 is provided only downstream of the filter chamber 76 in the internal flow path 30, it becomes easier to suppress the outflow of air leaking from the air reservoir 154 into the secondary flow path 34 of the liquid flow path 14. Consequently, when no air intake abnormality occurs, it becomes easier to maintain a state in which as much air as possible is secured upstream of the filter chamber 76.

[0076] Other features of the filter assembly 12 will now be described. Refer to Figures 10A and 10B. The filter assembly 12 includes a drain passage 158 for draining residual liquid 156 remaining at the bottom of the downstream liquid chamber 98 when the filter cartridge 54 is placed on its side, to the outside of the filter assembly 12. The residual liquid 156 here refers to the liquid remaining in the internal flow path 30 of the filter assembly 12 when such a draw-in abnormality occurs. In this embodiment, the outlet flow path 100 of the internal flow path 30 also serves as the drain passage 158. This simplifies the configuration compared to providing a separate drain passage 158 from the outlet flow path 100.

[0077] The drain passage 158, which also serves as the outlet passage 100, guides the remaining liquid 156 in the downstream liquid chamber 98 to the inlet 110a of the secondary flow path member 110, and allows it to be discharged to the outside from the inlet 110a. The remaining liquid 156 guided to the inlet 110a by the drain passage 158 is drawn downstream in the secondary flow path 34 and discharged to the outside of the filter assembly 12. When the filter assembly 12 is installed in a horizontal orientation, it can also be said that it is configured to allow the remaining liquid remaining at the bottom of the downstream liquid chamber 98 to be discharged to the outside (in this case, the secondary flow path 34) through the drain passage 158.

[0078] The drain passage 158 in this embodiment can discharge the residual liquid 156 remaining in the lower part of the downstream liquid chamber 98 until its liquid level falls below the entire filter chamber 76 of the filter cartridge 54. To achieve this, the drain passage 158 is located below the entire filter chamber 76 throughout its entire flow direction. Furthermore, the drain passage 158 in this embodiment can discharge the residual liquid 156 remaining in the lower part of the downstream liquid chamber 98 until its liquid level in a cross-section along the centerline C54 of the filter cartridge 54 is below the upper end position 98a of the downstream liquid chamber 98. To achieve this, the drain passage 158 is located below the upper end position 98a of the downstream liquid chamber 98 throughout its entire flow direction.

[0079] The inlet portion 158a of the drain passage 158 opens at the lower part of the downstream liquid chamber 98, specifically at the location including the lower end of the downstream liquid chamber 98. In this case, the inlet portion 158a of the drain passage 158 opens at the bottom surface of the central recess 58c (the bottom surface of the bottom recess 58g) at the lower end of the downstream liquid chamber 98. Alternatively, the inlet portion 158a of the drain passage 158 may also open at the lower surface of the lower end of the downstream liquid chamber 98.

[0080] Thus, the filter assembly 12 is equipped with a drain passage 158 for discharging residual liquid 156 remaining at the bottom of the downstream liquid chamber 98 to the outside. Therefore, after a draw-in abnormality occurs, the amount of residual liquid can be reduced as much as possible by discharging the residual liquid 156 remaining in the downstream liquid chamber 98 to the outside through the drain passage 158. Consequently, when the filter cartridge 54 is moved relative to the fixing member 58 for removal of the filter cartridge 54, the amount of residual liquid spilled to the outside from the part of the fixing member 58 that becomes the downstream liquid chamber 98 can be reduced.

[0081] Next, the features of the filtration system 10 will be described. Refer to Figure 1. The filtration system 10 includes a liquid detection unit 160 that detects the presence or absence of liquid at a detection point downstream of the air reservoir 154 in the liquid flow path 14. The detection point here refers to the section between the air reservoir 154 and the liquid supply unit 18 in the secondary flow path 34 of the liquid flow path 14.

[0082] The liquid detection unit 160 includes a sensor 162 that detects a physical quantity that changes depending on the material flowing through the location to be detected in the liquid flow path 14, and a determination unit 164 that determines the presence or absence of liquid based on the detection result of the sensor 162. The sensor 162 in this embodiment is a capacitance sensor that detects the capacitance of the material as a physical quantity that changes depending on the material flowing through the location to be detected in the liquid flow path 14. The sensor 162 in this embodiment is located outside the flow path member that forms the liquid flow path 14, but it may also be located inside it.

[0083] The determination unit 164 determines the presence or absence of liquid by comparing the detected value of the sensor 162 with a preset determination value. In this embodiment, when the sensor 162 detects capacitance, the detected value (capacitance) of the sensor 162 increases when a high dielectric constant liquid 150 flows through the liquid channel 14, and decreases when a low dielectric constant air flows through the liquid channel 14. Therefore, in this embodiment, if the detected value (capacitance) of the sensor 162 exceeds the determination value, the determination unit 164 determines that liquid 150 is flowing through the detected location in the liquid channel 14 and that there is liquid. Conversely, if the detected value (capacitance) of the sensor 162 is less than or equal to the determination value, the determination unit 164 determines that air is flowing through the detected location in the liquid channel 14 and that there is no liquid. The determination value is set so as to distinguish between the detected value when the substance flowing through the detected location in the liquid channel 14 is liquid and the detected value when the substance flowing through is air.

[0084] The determination unit 164 detects the presence of liquid if it determines that liquid is present. The determination unit 164 detects the absence of liquid if it determines that liquid is absent. In addition, the determination unit 164 may also detect the absence of liquid if it has determined that liquid is absent a predetermined number of times consecutively. The determination unit 164 outputs the detection result regarding the presence or absence of liquid to the control unit 20.

[0085] As described above, the liquid detection unit 160 of this embodiment detects the presence or absence of liquid at a location to be detected by detecting a physical quantity that changes depending on the material flowing through that location in the liquid flow path 14 using a sensor 162. This allows the detection of a liquid suction abnormality in the filter assembly 12 using the detection result of the liquid detection unit 160. For example, if the liquid detection unit 160 detects the presence of liquid, it can be determined that no liquid suction abnormality has occurred. Conversely, if the liquid detection unit 160 detects the absence of liquid, it can be determined that a liquid suction abnormality has occurred. The control unit 20 may also notify the user of a liquid suction abnormality in a manner perceptible to the user through a notification unit (not shown). The notification unit may be, for example, a lamp, speaker, or display.

[0086] (Second Embodiment) Refer to Figure 11. The filter assembly 12 of the second embodiment will be described.Hereafter, among the components described in the first embodiment, components not described below will be treated the same as in the first embodiment unless there is a particular inconsistency.The filter assembly 12 of the second embodiment differs from the filter assembly 12 of the first embodiment in features related to the second improvement.

[0087] In this embodiment, the inlet channel 90 of the internal channel 30 is located below the centerline C54 of the filter cartridge 54, and the outlet channel 100 of the internal channel 30 is located above the centerline C54 of the filter cartridge 54. The outlet channel 100 is located above the inlet hole 94 of the filter cartridge 54.

[0088] In this embodiment, the submerged portion 152 that blocks the flow of air within the internal flow path 30 is provided at least at the inlet hole 94 of the internal flow path 30. As a result, an air reservoir 154 is provided in the upstream liquid chamber 92 of the internal flow path 30, where air is sealed in by the liquid 150 accumulated in the upstream liquid chamber 92. The air reservoir 154 in the upstream liquid chamber 92 is provided when the liquid 150 is accumulated in the internal flow path 30 until the inlet hole 94, which becomes the submerged portion 152, is submerged below the liquid surface 150a. Here, an example in which there is only one inlet hole 94 is described. If there are multiple inlet holes 94, the air reservoir 154 is provided when all of the inlet holes 94 are submerged below the liquid surface 150a of the liquid 150.

[0089] In the internal flow path 30, downstream of the submerged area 152 (filter chamber 76, downstream liquid chamber 98), the liquid 150 is accumulated above the liquid level 150a of the liquid 150 stored in the upstream liquid chamber 92. Here, the flow direction Db of the liquid 150 when liquid is passed through the internal flow path 30 in a normal state where no draw-in abnormality occurs is shown. In this embodiment, in the internal flow path 30, downstream of the submerged area 152 (filter chamber 76, downstream liquid chamber 98, etc.), the liquid 150 passes above the liquid level 150a of the liquid 150 stored in the upstream liquid chamber 92.

[0090] A method for bleeding air from the filter assembly 12 to provide an air reservoir 154 within the filter assembly 12 of this embodiment will be described. Refer to Figures 12A to 12C. Here, an example is shown in which the state transitions in the order of Figure 12A → Figure 12B → Figure 12C as the air bleeding progresses. The liquid flow direction Db is also shown in each figure. Assume the state immediately after a new filter cartridge 54 has been placed inside the filter assembly 12. Under this state, when the liquid supply unit 18 applies negative pressure to the liquid flow path 14, drawing it towards the liquid supply unit 18, the liquid supplied from the liquid source 16 flows into the internal flow path 30 of the filter assembly 12 via the primary flow path 32. As the amount of liquid flowing into the internal flow path 30 increases, the air in the internal flow path 30 is drawn into the secondary flow path 34, and the liquid level of the liquid 150 in the area including the submerged portion 152 of the internal flow path 30 (in the second embodiment, the inlet hole 94) gradually rises in direction De (see Figures 12A and 12B). When the submerged portion 152 of the internal flow path 30 is filled with liquid 150, an air pocket 154 is formed upstream of that point in the internal flow path 30 (see Figure 12C). Up to this point, the process is the same as in the first embodiment.

[0091] In this embodiment, as the amount of liquid 150 flowing into the internal flow path 30 increases, the liquid level of the liquid 150 stored in the upstream liquid chamber 92 gradually rises (see Figure 12A). When the liquid level of the liquid 150 in the upstream liquid chamber 92 rises to the level of the inlet hole 94, the liquid 150 flows into the filter chamber 76 from the inlet hole 94 and flows out of the filter chamber 76 through the outlet hole 96 into the downstream liquid chamber 98 (see Figure 12B). Under these conditions, as the amount of liquid 150 flowing into the internal flow path 30 increases, the liquid levels of the liquid 150 in the filter chamber 76 and the downstream liquid chamber 98 gradually rise. When the liquid level of the liquid 150 stored in the filter chamber 76 matches the liquid level of the liquid 150 stored in the upstream liquid chamber 92, the liquid levels of the liquid 150 stored in both gradually rise until the inlet hole 94 is submerged. When the liquid level of the liquid 150 stored in the upstream liquid chamber 92 rises to the point where the inlet hole 94 is submerged, an air pocket 154 is formed in the upstream liquid chamber 92, which is upstream of that point (see Figure 12C). From this point onward, as the amount of liquid 150 flowing into the internal flow path 30 increases, the liquid levels of the liquid 150 stored in the filter chamber 76 and the downstream liquid chamber 98 gradually rise.

[0092] By raising the liquid level 150 accumulated in the filter chamber 76 in this way, air is discharged from the filter chamber 76 to the secondary flow path 34 through the outlet hole 96 of the filter cartridge 54. This air discharge from the filter chamber 76 refers to the process of discharging the air from the filter chamber 76 after placing a new filter cartridge 54, which is now filled with air in the filter chamber 76, into the inner chamber 52 of the housing 50.

[0093] Refer to Figures 12B and 12C. In this embodiment, the filter assembly 12 includes an air vent passage 170 for discharging air remaining in the upper part of the filter chamber 76 to the outside of the filter assembly 12 when the filter cartridge 54 is oriented horizontally. In this embodiment, the outlet passage 100 of the internal passage 30 also serves as the air vent passage 170. This simplifies the configuration compared to providing a separate air vent passage 170 in addition to the outlet passage 100.

[0094] When the filter chamber 76 is bled, the air inside the filter chamber 76 flows out of the filter chamber 76 through the outlet hole 96 to the downstream liquid chamber 98, and is then discharged to the outside through the downstream liquid chamber 98 and the air bleed passage 170. Here, the direction of air flow Df during air bleed is shown. When the air bleed passage 170 also serves as the outlet passage 100, the air inside the filter chamber 76 is discharged to the outside through the inlet 110a of the secondary flow path member 110 attached to the outlet hole 100a of the outlet passage 100. At this time, the air inside the filter chamber 76 is drawn downstream from the inlet 110a of the secondary flow path member 110 in the secondary flow path 34 and discharged to the outside. When the filter assembly 12 is installed in a horizontal orientation, it can also be said that when the filter chamber 76 is bled, the air remaining in the upper part of the filter chamber 76 is discharged to the outside (in this case, the secondary flow path 34) through the air bleed passage 170.

[0095] Refer to Figure 12C. The air vent passage 170 is capable of discharging air remaining in the upper part of the filter chamber 76 to the outside until the liquid level 150a of the liquid 150 accumulated in the filter chamber 76 is at least above the uppermost outlet hole 96 of the filter cartridge 54. Here, "uppermost outlet hole 96" refers to the outlet hole 96 if the filter cartridge 54 has only one outlet hole 96, or the uppermost outlet hole 96 of the multiple outlet holes 96 if the filter cartridge 54 has multiple outlet holes 96. To satisfy this condition, the air vent passage 170 is positioned above the uppermost outlet hole 96 of the filter cartridge 54 throughout its entire flow direction. This allows air remaining in the upper part of the filter chamber 76 to be discharged to the outside through the air vent passage 170 until the uppermost outlet hole 96 of the filter cartridge 54 is submerged in the liquid 150 during the process of raising the liquid level of the liquid 150 in the filter chamber 76. Air remaining above the uppermost outlet 96 within the filter chamber 76 may be discharged to the outside through the air vent passage 170 as the liquid level in the liquid stored in the filter chamber 76 fluctuates. Figure 11 shows an example in which the air in the filter chamber 76 is completely discharged in this manner.

[0096] Thus, the filter assembly 12 is equipped with an air vent passage 170 for releasing residual air remaining in the upper part of the filter chamber 76 to the outside when the liquid level in the filter chamber 76 is raised when the filter cartridge 54 is oriented horizontally. Therefore, even when the filter cartridge 54 is oriented horizontally, the amount of liquid that can be stored in the filter chamber 76 can be increased by discharging residual air to the outside through the air vent passage 170. Consequently, the liquid can pass through as wide an area of ​​the filter 74 in the filter chamber 76 as possible, allowing the filter 74 to be used efficiently.

[0097] (Third Embodiment) Refer to Figure 13. The filter assembly 12 of the third embodiment will be described. The filter assembly 12 of the third embodiment differs from the filter assembly 12 of the second embodiment in its configuration and installation configuration. Specifically, the filter assembly 12 of this embodiment is installed in a vertical orientation in which the center line C54 of the filter cartridge 54 is oriented vertically. To achieve this, the housing 42 of the filter unit 40, including the filter assembly 12, is installed on the base 44 (not shown) so that the center line C54 of the filter cartridge 54 is oriented vertically. Here, "vertical orientation" includes not only the case in which the center line C54 of the filter cartridge 54 is positioned parallel to the vertical line, but also the case in which the center line C54 is positioned approximately parallel to the vertical line.

[0098] The filter assembly 12 is configured to discharge any air remaining in the upper part of the filter chamber 76 through the outlet passage 100 when air is being bled from the filter chamber 76. To achieve this, when the filter cartridge 54 is oriented vertically, the outlet passage 100 is positioned above the outlet holes 96 of the filter cartridge 54 throughout its entire flow direction. To satisfy this condition, if the filter cartridge 54 has multiple outlet holes 96, the outlet passage 100 is positioned above each outlet hole 96. This allows air remaining in the upper part of the filter chamber 76 to be discharged through the outlet passage 100 to the outside (in this case, the secondary passage 34) until the outlet holes 96 of the filter cartridge 54 are submerged in the liquid 150 during the process of raising the liquid level in the filter chamber 76.

[0099] This allows residual air in the filter chamber 76 to be discharged to the outside through the outlet passage 100 when the liquid level in the filter chamber 76 is raised, even when the filter cartridge 54 is oriented vertically. Consequently, whether the filter cartridge 54 is oriented vertically or horizontally, residual air in the filter chamber 76 can be released to the outside as much as possible.

[0100] In this explanation, we have described the case where the filter assembly 12 of the second embodiment is installed in a vertical orientation instead of a horizontal orientation. In addition, even when the filter assembly 12 of the first embodiment is installed in a vertical orientation instead of a horizontal orientation, it may be configured so that when air is bled from the filter chamber 76, the air remaining in the upper part of the filter chamber 76 can be discharged to the outside through the outlet passage 100.

[0101] Furthermore, this example shows that the submerged portion 152 in the internal flow path 30 is provided at least at the inlet hole 94. Figure 13 shows the flow direction Db of the liquid 150 when liquid is passed through the internal flow path 30 in a normal state where no draw-in abnormality has occurred. In this embodiment as well, similar to the second embodiment, the liquid 150 passes through the internal flow path 30 so as to pass above the liquid surface 150a of the liquid 150 accumulated in the upstream liquid chamber 92, downstream of the submerged portion 512 (filter chamber 76, downstream liquid chamber 98, etc.).

[0102] Next, we will describe the transformation forms of each component described so far.

[0103] The liquid-receiving section 28, to which the filtered liquid from the filtration system 10 is supplied, is not limited to the water supply channel 22 through which raw water flows, but may also be a water discharge device, a tank, etc. The filtration system 10 does not necessarily have to include the water supply channel 22, the modification cartridge 24, or the on / off valve 26.

[0104] In relation to the effect of (A), it is not necessary for the internal flow path 30 of the filter assembly 12 to have an air reservoir 154.

[0105] The filter assembly 12 does not necessarily have a second attachment / detachment structure 126. In this case, when the movable member 60 is removed from the fixed member 58, the filter assembly 12 may remain in the area that becomes the inner chamber 52 of the fixed member 58. The second attachment / detachment structure 126 may be constructed using a screw structure, a groove-and-groove fitting structure, a magnet, a screw member, etc., in addition to the elastic member 128. If there is no elastic member 128 that constitutes the second attachment / detachment structure 126, the liquid chamber (upstream liquid chamber 92 in this embodiment) that is divided by the elastic member 128 can be made wider. Accordingly, the amount of air that can be stored in the liquid chamber when an air reservoir 154 is provided in it can be increased.

[0106] In the example described, the inner chamber 52 is formed in order from the fixed member 58 side to the movable member 60 side in the axial direction, with a downstream liquid chamber 98, a filter chamber 76, and an upstream liquid chamber 92. In addition, the upstream liquid chamber 92, filter chamber 76, and downstream liquid chamber 98 may be formed in order from the fixed member 58 side to the movable member 60 side in the axial direction. In this case, the downstream liquid chamber 98 is formed between the filter cartridge 54 and the movable member 60 instead of the upstream liquid chamber 92. In this case, the elastic member 128 may divide the downstream liquid chamber 98 into two small chambers 140A and 140B.

[0107] Neither the movable member 60 nor the filter cartridge 54 is required to have a connecting channel 142 that connects the two small chambers 140A and 140B. In this case, only one of the small chambers 140A and 140B may be used as part of the internal channel 30. Alternatively, only the filter cartridge 54 may have a connecting channel 142, or both the movable member 60 and the filter cartridge 54 may have a connecting channel 142.

[0108] The communication channel 142 may be formed in a closed cross-sectional structure by either the movable member 60 or the filter cartridge 54. The groove may be provided on the outer circumferential surface of the filter cartridge 54 that crushes the elastic member 128. Alternatively, the groove may be provided on the surface that crushes the elastic member 128 in at least one of the movable member 60 and the filter cartridge 54.

[0109] An example has been described in which one member 120 to which the first sealing member 56 is attached is a filter cartridge 54, and the other member 122 is a fixing member 58. Alternatively, the one member 120 to which the first sealing member 56 is attached may be a fixing member 58, and the other member 122 may be a filter cartridge 54. The second pressing surface 122a of the other member 122 may be a flat surface perpendicular to the attachment / detachment direction Da.

[0110] In relation to the effect of (B), the first sealing member 56 may be compressed radially in the direction of the filter cartridge 54 between the fixing member 58 and the filter cartridge 54.

[0111] The air reservoir 154 may be located in any part of the internal flow path 30 (e.g., the upstream liquid chamber 92, the filter chamber 76, the downstream liquid chamber 98, etc.).

[0112] The drain passage 158 may be provided separately from the outlet passage 100 of the internal passage 30. The drain passage 158 may also discharge only the residual liquid remaining at the top of the downstream liquid chamber 98 when the filter cartridge 54 is oriented horizontally.

[0113] In this example, the drain passage 158 discharges the remaining liquid in the downstream liquid chamber 98 to the outside by negative pressure drawn into the secondary flow path 34. Alternatively, the drain passage 158 may discharge the remaining liquid in the downstream liquid chamber 98 to the outside by its own weight.

[0114] The air vent passage 170 may be provided separately from the outlet passage 100 of the internal passage 30. When the filter cartridge 54 is turned on its side, the air vent passage 170 may release only the air remaining in the lower part of the filter chamber 76 to the outside when the liquid level in the filter chamber 76 is raised.

[0115] In the example described, the air vent passage 170 raises the liquid level in the internal passage 30 by negative pressure drawn into the secondary passage 34, thereby discharging air from the filter chamber 76. Alternatively, the air vent passage 170 may raise the liquid level in the internal passage 30 by positive pressure pushed from the primary passage 32 into the internal passage 30, thereby discharging air from the filter chamber 76.

[0116] The inlet holes 94 of the filter cartridge 54 may be located in the cylindrical wall portion 80a of the filter cartridge 54. The number of inlet holes 94 of the filter cartridge 54 is not particularly limited, and there may be multiple inlet holes 94.

[0117] The liquid detection unit 160 only needs to be able to detect the presence or absence of liquid at the detection point within the liquid flow path 14, and its specific examples are not particularly limited. When sensor 162 is used in the liquid detection unit 160, the physical quantity to be detected by sensor 162 is not limited to capacitance, but may be temperature, light intensity, etc. When temperature is used as the physical quantity to be detected by sensor 162, the liquid detection unit 160 may be equipped with a heater to heat the liquid flow path 14 in addition to the aforementioned sensor 162 and determination unit 164. In this case, sensor 162 may be a thermistor or the like to detect temperature. Sensor 162 detects a first temperature after a first set time has elapsed from the start of heating of the liquid flow path 14 by the heater, and a second temperature after a second set time has elapsed from the start of heating. The temperature difference between the first and second temperatures becomes smaller when a liquid with a high heat transfer coefficient flows through the liquid flow path 14, and larger when air with a low heat transfer coefficient flows through the liquid flow path 14. Therefore, the determination unit 164 determines that liquid is flowing through the liquid channel 14 and that there is liquid if the temperature difference between the first temperature and the second temperature detected by the sensor 162 is less than a predetermined determination value. Conversely, the determination unit 164 determines that air is flowing through the liquid channel 14 and that there is no liquid if the temperature difference is less than the determination value.

[0118] The embodiments and variations described above are illustrative. The abstract technical ideas derived from them should not be interpreted restrictively to the content of the embodiments and variations. The content of the embodiments and variations can be modified in many ways, such as by changing, adding, or deleting components. In the embodiments described above, the content that allows for such design modifications is emphasized with the notation "embodiment." However, design modifications are naturally permitted even in content without such notation. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied. Any substitution of any of the components and expressions of this disclosure between methods, apparatus, systems, etc., is also valid as an embodiment of this disclosure.

[0119] The technical ideas embodied in the above embodiments and variations can be generalized to include the technical ideas described in the following items.

[0120] The first item is a filter assembly comprising a housing having a fixed member and a movable member that is detachable from the fixed member and cooperates with the fixed member to form an inner chamber, and a filter cartridge housed in the inner chamber, wherein the housing and the filter cartridge become part of a liquid flow path through which liquid flows, forming an internal flow path that passes through a filter built into the filter cartridge, and the internal flow path is provided with an air reservoir through which air is sealed by the liquid accumulated in the internal flow path.

[0121] The second item is the filter assembly described in the first item, wherein the filter assembly is installed in a horizontal orientation such that the center line of the filter cartridge is horizontal, the filter cartridge has a downstream liquid chamber formed between it and the fixing member, which is located downstream of the filter chamber housing the filter in the internal flow path, and the filter assembly has a drainage passage for discharging any remaining liquid at the bottom of the downstream liquid chamber to the outside.

[0122] The third item is the filter assembly described in item 2, wherein the outlet passage of the internal passage also serves as the drain passage.

[0123] The fourth item is a filter assembly according to any one of the first to third items, wherein the filter assembly is installed in a horizontal orientation such that the center line of the filter cartridge is horizontal, the filter cartridge comprises a filter chamber for housing the filter, and an air vent passage for discharging air remaining in the upper part of the filter chamber to the outside when the air in the filter chamber is vented.

[0124] The fifth item is the filter assembly described in item 4, in which the outlet passage of the internal passage also serves as the air vent passage.

[0125] The sixth item is a filter assembly according to any of the third to fifth items, wherein the filter assembly is installed in a vertical orientation, with the center line of the filter cartridge being vertical, instead of the horizontal orientation, and the filter assembly is configured to discharge the air remaining in the upper part of the filter chamber to the outside through the outlet passage when the air in the filter chamber is bled.

[0126] The seventh item is a filter assembly according to any one of the first to sixth items, wherein the filter cartridge comprises a filter chamber for housing the filter, and the air reservoir is provided at least upstream of the filter chamber in the internal flow path.

[0127] The eighth item is a filter assembly according to any of the first to seventh items, comprising a bottomed cylindrical case body that forms a filter chamber for housing the filter, and an inlet for allowing liquid to flow into the filter chamber from upstream of the filter chamber in the internal flow path, wherein the inlet is provided on the bottom wall of the case body.

[0128] The ninth item is the filter assembly described in item eight, wherein the inlet hole is located on the center line of the filter cartridge.

[0129] The tenth item is a filter assembly according to either the eighth or ninth item, wherein the filter assembly is installed in a lateral configuration such that the center line of the filter cartridge is horizontal, and the outlet channel of the internal channel is located below the inlet hole.

[0130] The 11th item is a filter assembly according to any one of the first to tenth items, wherein the filter assembly is used in a filtration system, and the filtration system comprises a liquid delivery unit that draws the fluid in the internal flow path to a downstream side of the internal flow path in the liquid flow path, and a liquid detection unit that detects the presence or absence of liquid downstream of the air reservoir in the liquid flow path.

[0131] The 12th item is a filtration system comprising: a liquid channel through which liquid flows; a filter assembly described in any of the 1st to 10th items provided in the liquid channel; a liquid delivery unit that draws the fluid in the internal channel to a downstream side of the internal channel in the liquid channel; and a liquid detection unit that detects the presence or absence of liquid downstream of the air reservoir in the liquid channel. [Explanation of Symbols]

[0132] 10...Filtration system, 12...Filter assembly, 14...Liquid flow path, 18...Liquid delivery section, 30...Internal flow path, 50...Housing, 52...Inner chamber, 54...Filter cartridge, 56...First sealing member, 58...Fixing member, 60...Movable member, 64...Liquid delivery section, 66...Fixed part, 74...Filter, 76...Filter chamber, 80...Case body, 80b...Bottom wall section, 92...Upstream liquid chamber, 9 4...Inlet hole, 98...Downstream liquid chamber, 100...Outlet passage, 120...One member, 120a...Circumferential surface, 120b...First pressing surface, 122...Other member, 122a...Second pressing surface, 126...Second detachable structure, 128...Elastic member, 140A, 140B...Small chamber, 142...Communicating passage, 150...Liquid, 156...Residual liquid, 158...Liquid drainage passage, 160...Liquid detection unit, 170...Air venting passage.

Claims

1. A filter assembly used in a filtration system, The aforementioned filtration system is The filter assembly has an internal channel formed in which it becomes part of a liquid channel through which the liquid flows, A liquid supply unit that draws the fluid in the internal channel downstream of the internal channel in the liquid channel, The liquid flow path includes a liquid detection unit that detects the presence or absence of liquid downstream of the internal flow path and upstream of the liquid delivery unit, The aforementioned filter assembly is A housing having a fixing member and a movable member that is detachable from the fixing member and cooperates with the fixing member to form an inner chamber, The system comprises a filter cartridge housed in the aforementioned internal chamber, The housing and the filter cartridge form the internal flow path through the filter built into the filter cartridge. A filter assembly in which the internal flow path is provided with an air reservoir into which air is sealed by the liquid accumulated in the internal flow path.

2. The filter assembly is installed in a horizontal orientation such that the center line of the filter cartridge is horizontal. The filter cartridge has a downstream liquid chamber formed between the fixing member and the internal flow path, which is located downstream of the filter chamber housing the filter. The filter assembly according to claim 1, further comprising a drainage passage for discharging residual liquid remaining at the bottom of the downstream liquid chamber to the outside.

3. The filter assembly according to claim 2, wherein the outlet passage of the internal passage also serves as the liquid drain passage.

4. The filter assembly is installed in a horizontal orientation such that the center line of the filter cartridge is horizontal. The filter cartridge comprises a filter chamber for housing the filter, The filter assembly according to claim 1, further comprising an air venting passage for discharging air remaining in the upper part of the filter chamber to the outside when the filter chamber is vented.

5. The filter assembly according to claim 4, wherein the outlet passage of the internal passage also serves as the air vent passage.

6. The filter assembly is installed in a vertical orientation, instead of the horizontal orientation, where the center line of the filter cartridge is vertical. The filter assembly according to claim 3 or 5, wherein the filter assembly is configured to discharge air remaining in the upper part of the filter chamber to the outside through the outlet passage when air is bled from the filter chamber.

7. The filter cartridge comprises a filter chamber for housing the filter, The filter assembly according to claim 1, wherein the air reservoir is provided at least upstream of the filter chamber in the internal flow path.

8. The filter cartridge comprises a bottomed cylindrical case body that forms a filter chamber for housing the filter, and an inlet for allowing liquid to flow into the filter chamber from upstream of the filter chamber in the internal flow path. The filter assembly according to claim 1, wherein the inlet hole is provided in the bottom wall of the case body.

9. The filter assembly according to claim 8, wherein the inlet hole is provided on the center line of the filter cartridge.

10. The filter assembly is installed in a horizontal orientation such that the center line of the filter cartridge is horizontal. The filter assembly according to claim 8, wherein the outlet channel of the internal channel is provided below the inlet hole.

11. A liquid channel through which liquid flows, A filter assembly according to any one of claims 1 to 5, 7 to 10 is provided in the liquid flow path, A liquid supply unit that draws the fluid in the internal channel downstream of the internal channel in the liquid channel, A filtration system comprising a liquid detection unit that detects the presence or absence of liquid in the liquid flow path downstream of the internal flow path and upstream of the liquid delivery unit.

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