CN117043462A

CN117043462A - Circulation flow device

Info

Publication number: CN117043462A
Application number: CN202280011503.1A
Authority: CN
Inventors: K·T·威利斯; J·C·萨瓦斯若姆; K·C·罗伯森; D·O·琼斯
Original assignee: Donaldson Co Inc
Current assignee: Donaldson Co Inc
Priority date: 2021-01-29
Filing date: 2022-01-28
Publication date: 2023-11-10
Also published as: AU2022214311A1; MX2023008468A; US20220244747A1; JP2024507639A; CA3205831A1; KR20230133323A; WO2022165131A1; EP4285022A1

Abstract

A circulating flow apparatus consistent with the techniques disclosed herein is configured to be sealably coupled to a liquid flow circuit. The circulating flow apparatus is configured to vary a flow rate of liquid through the filter media holder. In various embodiments, the circulating flow device is configured to vary a flow rate of liquid through a portion of the liquid flow circuit. The circulation flow device may be configured to cyclically vary a flow rate of liquid in the liquid flow circuit through the filter media holder.

Description

Circulation flow device

The application claims the benefit of U.S. provisional application No. 63/143,174 filed on 1 month 29 of 2021, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to a flow apparatus. More particularly, the present disclosure relates to a circulating flow apparatus.

Background

In the development of filter media, fluid flow test stations are often employed to help test the effectiveness of the filter media. The test station typically defines a closed liquid flow circuit through which fluid is pumped. The filter media is typically mounted within the liquid flow circuit of the test stand such that the pumped fluid passes through the filter media. The fluid is typically charged with one or more contaminants upstream of the filter medium, and the effectiveness of the filter medium in separating the contaminants may be quantified based on a variety of parameters including efficiency, pressure drop, collection capacity, and the like.

Typically, the fluid of the test station is pumped through the liquid flow circuit at a constant flow rate. In many practical embodiments of filter media, however, the flow rate may vary during use. Such flow rate variations can affect the performance of the filter media. It is therefore of general interest to be able to test filter media under variable flow conditions. While test stations have been developed that circulate the flow rate of fluid flow in the test station, such test stations are relatively large and complex and can be cost prohibitive.

Disclosure of Invention

The circulation flow devices described herein are configured to be installed along a liquid flow circuit to achieve varying flow rates through at least a portion of the liquid flow circuit. The circulation flow device may be a component of a liquid flow circuit or it may be a retrofit device configured to be installed in an existing liquid flow circuit. In the latter case, the existing liquid flow circuit may be designed to have a constant flow rate, and the circulating flow apparatus may be a retrofit device that modifies the liquid flow circuit to have a variable flow rate instead of a constant flow rate.

In some embodiments, the present technology relates to a circulating flow apparatus. The housing has a first variable volume and a first flow opening. The first flow opening extends to a first variable volume. The housing has a movable side wall defining a first variable volume. The first conduit coupling surrounds the first flow opening. The linear actuator is fixed to the movable side wall.

In some such embodiments, the movable sidewall is a piston. Additionally or alternatively, the linear actuator and the movable sidewall are configured to vary a flow rate of the liquid in the liquid flow circuit. Additionally or alternatively, the first conduit coupling is configured to sealably couple to the liquid flow circuit. Additionally or alternatively, the piston has a media opening defining a flow path in fluid communication with the first variable volume. Additionally or alternatively, the piston includes a media coupling structure surrounding the media opening. Additionally or alternatively, the piston forms a fluid seal with the housing across the first variable volume. Additionally or alternatively, the first flow opening is a flow inlet and a flow outlet. Additionally or alternatively, the first flow opening is a flow inlet and the first flow opening is not a flow outlet. Additionally or alternatively, the housing has a complementary variable volume, wherein the movable sidewall defines the complementary variable volume. Additionally or alternatively, the housing has a second flow opening extending to a complementary variable volume. Additionally or alternatively, the circulating flow apparatus is a retrofit device.

Some examples of the current technology relate to a circulating flow apparatus having a housing and a piston. The housing has a flow inlet, a flow outlet, and a cavity extending in an axial direction from the flow inlet to the flow outlet. The piston is disposed across the cavity and forms a seal with the housing. The piston is linearly translatable in an axial direction along the cavity. The piston defines an axially extending media opening in fluid communication with the cavity.

In some such embodiments, the apparatus has an actuator translatably coupled to the piston. Additionally or alternatively, the actuator is configured to cyclically translate the piston between a first position and a second position in the cavity. Additionally or alternatively, the first position is toward a first end of the cavity and the second position is toward a second end of the cavity. Additionally or alternatively, the piston defines a media coupling structure surrounding the media opening.

Some other examples of the current technology relate to a circulating flow apparatus. The housing has a first variable volume, the housing defining a first flow opening and a conduit coupling surrounding the first flow opening. The conduit coupling is configured to be detachably coupled to the liquid flow circuit. An actuator is in operative communication with the housing. The actuator is configured to cause the housing to cyclically accumulate liquid in the liquid flow circuit in the first variable volume and release liquid from the first variable volume to the liquid flow circuit.

In some such embodiments, the apparatus has a flow sensor positioned in the first flow opening and a controller coupled to the actuator. The controller is in data communication with the flow sensor. Additionally or alternatively, the housing is a cylinder. Additionally or alternatively, the system has a piston translatably disposed in the cylinder, wherein the first variable volume is defined by the cylinder and the piston. Additionally or alternatively, the complementary variable volume is defined by a cylinder and a piston, wherein the cylinder defines a second flow opening extending to the complementary variable volume. Additionally or alternatively, the first variable volume is a bladder. Additionally or alternatively, the first flow opening is a flow inlet and a flow outlet. Additionally or alternatively, the first flow opening is a flow inlet and the first flow opening is not a flow outlet. Additionally or alternatively, the circulating flow apparatus is a retrofit device.

In some other example embodiments, the present technology relates to a circulating flow apparatus having a housing defining a first variable volume and a complementary variable volume. The housing includes a shell having a fixed volume. A bladder is disposed in the housing. The bladder defines a first variable volume. The bladder inlet extends to the first variable volume and the bladder outlet extends from the first variable volume. A complementary variable volume is defined between the bladder and the housing. The housing defines a housing inlet and a housing outlet. The flow control valve is operably coupled to the bladder outlet. An actuator is operably coupled to the flow control valve. The actuator is configured to oscillate the flow control valve between a restricted position and an open position.

In some such embodiments, the bladder inlet and the housing inlet are located at opposite axial ends of the housing. Additionally or alternatively, a flow sensor is positioned near the bladder outlet and a controller is coupled to the actuator, wherein the controller is in data communication with the flow sensor. Additionally or alternatively, the apparatus has a first conduit coupling around the bladder outlet, a second conduit coupling around the housing outlet, a third conduit coupling around the bladder inlet, and a fourth conduit coupling around the housing inlet, wherein each conduit coupling is configured to couple to the liquid flow circuit. Additionally or alternatively, the actuator is configured to cause the bladder to cyclically accumulate and release liquid. Additionally or alternatively, the circulating flow apparatus is a retrofit device.

Some embodiments of the present technology relate to a circulating flow apparatus having a housing defining a first variable volume and a first flow opening extending to the first variable volume. The housing has a movable side wall defining a first variable volume. An actuator is operably coupled to the movable sidewall. The flow sensor is configured to sense a liquid flow rate. A controller is in data communication with the flow sensor and in operative communication with the actuator. The controller is configured to operate the actuator to define a liquid flow rate relative to the flow sensor.

In some such embodiments, the movable sidewall includes a piston. Additionally or alternatively, the piston defines an opening and a media coupling structure surrounding the opening. Additionally or alternatively, a flow sensor is provided on the piston. Additionally or alternatively, the flow sensor is disposed proximate the first flow opening. Additionally or alternatively, the actuator is a linear actuator. Additionally or alternatively, the actuator is configured to operate the flow control valve. Additionally or alternatively, the housing has a first conduit coupling surrounding the first flow opening, wherein the first conduit coupling is configured to sealably couple to the liquid flow circuit. Additionally or alternatively, the first flow opening is a flow inlet and a flow outlet. Additionally or alternatively, the first flow opening is a flow inlet and the first flow opening is not a flow outlet. Additionally or alternatively, the housing has a complementary variable volume, wherein the movable sidewall defines the complementary variable volume. Additionally or alternatively, the housing has a second flow opening extending to a complementary variable volume.

The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete appreciation of the illustrative embodiments will be apparent and appreciated by reference to the following detailed description of the illustrative embodiments and the claims in view of the accompanying drawings.

Drawings

FIG. 1 is a schematic flow diagram of an example test bench consistent with example implementations of the current technology.

FIG. 2 is a schematic flow diagram of another example test bench consistent with another example embodiment of the current technology.

Fig. 3 is a schematic cross-sectional view of an example circulating flow apparatus.

Fig. 4 is a schematic cross-sectional view of another example circulation flow device.

Fig. 5 is a schematic cross-sectional view of yet another example circulating flow apparatus.

Fig. 6 is a schematic cross-sectional view of yet another example circulating flow apparatus.

Fig. 7 is a schematic cross-sectional view of an alternative exemplary variable volume housing.

Fig. 8 is a schematic cross-sectional view of yet another example circulation flow device.

Fig. 9 is a schematic cross-sectional view of yet another example circulation flow device.

The present technology will be understood and appreciated more fully from a consideration of the following detailed description of various embodiments, taken in conjunction with the accompanying drawings.

The figures are presented primarily for clarity and, therefore, are not necessarily drawn to scale. Further, various structures/components, including but not limited to fasteners, electrical components (cabling, etc.), and the like, may be schematically shown or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or inclusion of such structures/components is not necessary to an understanding of the various exemplary embodiments described herein. However, the absence of showing/describing such structures/components in a particular figure is not to be construed as limiting the scope of the various embodiments in any way.

Detailed Description

Circulation flow devices consistent with the technology disclosed herein may have a variety of different configurations. The circulation flow device is typically configured to vary the flow rate of the liquid through the filter media holder. In various embodiments, the circulation flow device is configured to vary a flow rate of the liquid through a portion of the liquid flow circuit. The circulation flow device may be configured to cyclically vary a flow rate of the liquid in the liquid flow circuit through the filter media holder. Such cycling of the flow rate through the filter media holder may advantageously provide a media testing environment that provides a representation of a real operating environment that is closer to the filter media. "circular flow" is generally defined as the flow rate that fluctuates in a repeating pattern over time.

The circulation flow device may be a retrofit device configured to be sealably coupled to an existing liquid flow circuit or an integral component of a liquid flow circuit. In the case where the circulation flow device is a retrofit device, the circulation flow device is configured to be installed in an existing liquid flow circuit. The existing liquid flow circuit may be configured to have a constant flow rate, and the circulating flow apparatus may be a retrofit device that modifies the liquid flow circuit to have a varying flow rate rather than a constant flow rate. A "retrofit device" as defined herein is an accessory component configured to be added to an existing system to modify the system. In various embodiments, the circulation flow device is a retrofit device configured to modify a constant flow rate liquid flow circuit to exhibit circulation flow conditions through a portion of the liquid flow circuit.

Fig. 1 is a schematic flow diagram of a first example liquid flow circuit 10 consistent with various embodiments of the present technology. The liquid flow circuit 10 is consistent with the multiple pass filter media test station in various embodiments. The liquid flow circuit 10 generally has an inlet line 12 extending from a fluid reservoir 20 to a filter media holder 30. The fluid reservoir 20 is generally configured to hold liquid passing through the liquid flow circuit 10. As examples, the liquid may be water, hydraulic fluid, fuel, and oil. Contaminant injector 22 is typically in fluid communication with fluid reservoir 20. The contaminant injector 22 is configured to inject contaminants into the fluid reservoir 20. In various embodiments, the contaminant injector 22 is configured to inject contaminants into the fluid reservoir 20 at a continuous rate. For example, the contaminant may be test dust.

Various components may be disposed along the inlet line 12 of the liquid flow circuit 10. For example, the pump 40 may be fluidly coupled to the inlet line 12. Pump 40 may be configured to induce a flow of liquid around liquid flow circuit 10. In various embodiments, the pump 40 is configured to induce a flow of liquid around the liquid flow circuit 10 at a particular liquid flow rate. In various embodiments, the particular liquid flow rate may be selected by a user, such as through a user interface in operative communication with pump 40.

The filter media retainer 30 is typically disposed across the inlet line 12. The filter media retainer 30 defines an opening that is a filtration pathway for liquid in the liquid flow circuit 10. The filter media retainer 30 is generally configured to secure the filter media around the opening such that liquid in the liquid flow circuit 10 passes through the filter media. The outlet line 14 extends from the filter media holder 30 to the fluid reservoir 20, wherein the outlet line 14 is configured to accommodate the flow of liquid from the filter media holder 30 to the fluid reservoir 20, at which time the liquid is then repeatedly circulated through the liquid flow circuit until the test is stopped. Various additional and alternative components may be provided along the outlet line 14.

The pressure sensor 50 is generally configured to sense a pressure differential across the media holder 30. In particular, the pressure sensor 50 may have a first sensor 52 configured to measure the liquid pressure on the upstream side of the media holder 30, and the pressure sensor 50 may have a second sensor 54 configured to measure the liquid pressure on the downstream side of the media holder 30. According to some test procedures, testing of the filter media is terminated when the pressure sensor 50 senses a threshold pressure differential across the media holder 30 (and thus across the filter media mounted to the media holder 30).

The liquid flow circuit 10 has an upstream particle counter 60 and a downstream particle counter 62. An upstream particle counter 60 is positioned along the liquid flow circuit 10 upstream of the media holder 30. Downstream particle counter 62 is positioned downstream of media retainer 30 along liquid flow circuit 10. Particle counters 60, 62 may be in accordance with particle counters known in the art.

A flow sensor 70 is generally positioned along the liquid flow circuit 10 and is configured to monitor the flow rate of liquid through the liquid flow circuit 10. In some embodiments, the flow sensor 70 communicates with a user interface to report the flow rate to the user. In some embodiments, the flow sensor 70 is in data communication with a controller that is in operative communication with the pump 40 to ensure that a constant flow rate is obtained. In some such embodiments, the flow sensor 70 may also be in data communication with a user interface to report the flow rate to a user.

FIG. 2 is a schematic flow diagram of another example test bench consistent with another example embodiment of the current technology. In various embodiments, the liquid flow circuit 11 is in accordance with a single pass filter media test stand. The liquid flow circuit 11 generally defines a single pass flow path 15 extending between the fluid reservoir 21 and the filter media retainer 31. More specifically, the single pass flow path 15 extends from the recirculation flow path 13 with the fluid reservoir 21 through the filter media retainer 31 to the drain tank 23. The single pass flow path 15 has an inlet line 12 extending from the recirculation flow path 13 to the filter media holder 31 and an outlet line 14 extending from the filter media holder 31 to the drain tank 23.

The fluid reservoir 21 is generally configured to hold a liquid through the single-pass flow path 15. As examples, the liquid may be water, hydraulic fluid, fuel, and oil. In the present example, the liquid contains contaminants such as test dust, and the liquid-contaminant mixture is recirculated through recirculation flow path 13 using recirculation pump 42 to prevent the contaminants from settling in reservoir 21.

Various components may be disposed along the single pass flow path 15. Sample pump 41 may be fluidly coupled to single pass flow path 15. The sample pump 41 may be configured to induce a flow of liquid through the single pass flow path 15. In various embodiments, the sample pump 41 is configured to induce a liquid flow through the single pass flow path at a particular liquid flow rate. In various embodiments, the particular liquid flow rate may be selected by a user, such as through a user interface in operative communication with the sample pump 41.

The filter media retainer 31 is generally disposed across the single pass flow path 15. The filter media retainer 31 defines an opening that is a filter passage for liquid in the single pass flow path 15. The filter media retainer 31 is generally configured to secure the filter media around the opening such that liquid in the single pass flow path 15 passes through the filter media. The single pass flow path 15 extends from the filter media holder 31 to a drain tank 23 in which liquid filtered by the filter media (on the filter media holder 31) is held.

The pressure sensor 51 is generally configured to sense a pressure differential across the media retainer 31. The configuration of the pressure sensor 51 may be similar to that depicted in fig. 1, with a liquid pressure sensor on the upstream side of the media holder 31 and another liquid pressure sensor on the downstream side of the media holder 31. The single pass flow path 15 may also have an upstream particle counter 61 and a downstream particle counter 63 consistent with particle counters known in the art.

The flow sensor 71 is generally positioned along the single-pass flow path 15 and is configured to monitor the flow rate of the liquid through the single-pass flow path 15. In some embodiments, the flow sensor 71 communicates with a user interface to report the flow rate to the user. In some embodiments, the flow sensor 71 is in data communication with a controller that is in operative communication with the sample pump 41 to ensure that a constant flow rate is obtained. The flow sensor 71 may also be in data communication with a user interface to report the flow rate to a user.

The circulation flow devices described herein may generally be mounted on a liquid flow circuit (such as the liquid flow circuit depicted in fig. 1 and 2) to enable liquid flow through the liquid flow circuit to have a varying flow rate rather than a constant flow rate.

FIG. 3 depicts an example schematic cross-sectional view of an example circulating flow apparatus 100 consistent with various embodiments. The circulation flow device 100 has a housing 110 defining a first variable volume 116. The housing 110 has a movable side wall 124 defining a first variable volume 116. The housing 110 has a first flow opening 112 extending to a first variable volume 116.

The circulation flow device 100 is generally configured to vary the flow rate of liquid through the media holder 130. The circulation flow device 100 may be configured to create a circulating liquid flow condition through the media holder 130. In various embodiments, the circulation flow device 100 is configured to circulate a liquid flow rate through the media holder 130.

The housing 110 generally has a first flow opening 112, a second flow opening 114, and a cavity 111 extending from the first flow opening 112 to the second flow opening 114. A first flow opening 112 and a second flow opening 114 are defined on opposite axial ends of the housing 110. In various embodiments, the first flow opening 112 may be a flow inlet. In various embodiments, the second flow opening 114 may be a flow outlet. In various embodiments, the first flow opening 112 is only a flow inlet and not a flow outlet.

The movable sidewall 124 is a piston 124 disposed across the cavity 111. The piston 124 forms a fluid-tight seal with the inner surface of the housing 110. The piston 124 is generally linearly translatable in an axial direction along the cavity 111. Thus, the position of the piston 124 within the cavity 111 defines the volume of the first variable volume 116 and the volume of the complementary variable volume 118 on the opposite side of the piston 124. The first flow opening 112 extends to a first variable volume 116. The second flow opening 114 extends to a complementary variable volume 118.

The piston 124 has a media retainer 130 that is generally configured to hold filter media for testing. The media retainer 130 has a media coupling structure 131 that is generally configured to secure the filter media to the piston 124. The media coupling structure 131 is configured to form a seal around the edge of the filter media to direct fluid flow through the media. For example, the media coupling structure 131 may be a clamp. The media retainer 130 defines a media opening 132, which is an axially extending opening through the piston 124. The media opening 132 is in fluid communication with the cavity 111. The media opening 132 defines a flow path between the first variable volume 116 and the complementary variable volume 118. The media coupling structure 131 generally surrounds the media opening 132 such that the filter media coupled to the media coupling structure 131 extends across the media opening 132. The media opening 132 extends from the first variable volume 116 to the complementary variable volume 118.

In some embodiments, the media opening 132 is a plurality of discrete openings through the movable sidewall 124 that cumulatively define the media opening 132. Such a configuration advantageously provides structural support for the media across the media opening 132. In some other embodiments, a support screen (such as a wire mesh screen) is coupled to the movable sidewall 124 across the media opening 132, the support screen configured to provide support to the filter media. Other configurations may also be used.

The actuator 120 is generally operably coupled to the movable sidewall 124. In the present example, the actuator 120 is translatably coupled to the piston 124 via a shaft 122. In various embodiments, the actuator 120 is a linear actuator secured to the piston 124. The actuator 120 is configured to actuate linear translation of the piston 124 through the cavity 111. More specifically, actuator 120 is configured to cyclically translate piston 124 between a first position and a second position in cavity 111. The direction and speed of the piston 124 through the cavity 111 may define the direction, speed, or both the direction and speed of fluid flow through the media opening 132, and more particularly, the direction, speed, or both the direction and speed of fluid flow through the filter media of the media retainer 130 secured to the piston.

In various embodiments, the circulation flow device 100 is configured to be coupled to a liquid reservoir (not currently depicted). In various embodiments, the circulation flow device 100 is configured to be coupled to a liquid flow circuit 10 that may incorporate a liquid reservoir, where only a portion of the liquid flow circuit 10 is depicted at the present time. Although the element numbers associated with the multi-pass liquid flow circuit 10 described above with reference to fig. 1 are used herein in the discussion of the circulating flow apparatus, it should be understood that the liquid flow circuit may be consistent with the single-pass liquid flow circuit 11 discussed above with reference to fig. 2. In some embodiments, the circulation flow device 100 is integral with the liquid flow circuit 10. However, in some other examples, the circulation flow device 100 is configured to be coupled to the liquid flow circuit 10. The circulation flow device 100 has a first conduit coupling 113 surrounding the first flow opening 112. The first conduit coupling 113 is configured to be sealably coupled to a flow line of the liquid flow circuit 10, such as the inlet line 12, such that the first flow opening 112 is in direct fluid communication with the liquid flow circuit 10. In various embodiments, the first conduit coupling 113 is configured to be detachably coupled to the inlet line 12 of the liquid flow circuit 10. The first conduit coupling 113 may use a variety of different fastening mechanisms and combinations of fastening mechanisms commonly known in the art.

The circulation flow device 100 generally has a second conduit coupling 115 surrounding the second flow opening 114. The second conduit coupling 115 is configured to be sealably coupled to a flow line, such as the outlet line 14 of the liquid flow circuit 10, such that the second flow opening 114 is in direct fluid communication with the outlet line 14 of the liquid flow circuit 10. The second conduit coupling 115 is configured to be detachably coupled to the outlet line 14 of the liquid flow circuit 10. The second conduit coupling 115 may use a variety of different fastening mechanisms and combinations of fastening mechanisms commonly known in the art.

In the present example, the circulation flow device 100 is generally configured to be installed in the liquid flow circuit 10. In some embodiments, the circulation flow device 100 is configured to replace the media holder 30 of the liquid flow circuit 10. Thus, the media retainer 30 of the liquid flow circuit 10 may be removed, and the first conduit coupling 113 coupled to the inlet line 12 of the liquid flow circuit 10, and the second conduit coupling 115 coupled to the outlet line 14 of the liquid flow circuit 10. In some other embodiments, the circulation flow device 100 is configured to be integral with a liquid flow circuit. In some (but not all) such embodiments, the circulation flow device 100 may omit one or both of the first conduit coupling 113 and the second conduit coupling 115, with the inlet line 12 and/or the outlet line 14 being integral with the housing 110.

As discussed above, the liquid flow circuit 10 coupled to the circulating flow apparatus 100 is configured to circulate liquid through the flow circuit at a constant volumetric flow rate. When the movable sidewall 124 is stationary within the cavity 111, the velocity of the liquid through the media opening 132 (or through the filter media coupled to the piston 124 around the media opening) is constant and equal to the volumetric flow rate divided by the flow area of the media opening 132. As the movable sidewall 124 translates linearly through the cavity 111 toward the second flow opening 114, the velocity of the liquid passing through the media opening 132 decreases due to the linear velocity of the movable sidewall 124. As the movable sidewall 124 translates linearly through the cavity 111 toward the first flow opening 112, the velocity of the liquid passing through the media opening 132 increases due to the linear velocity of the movable sidewall 124. In this way, the fluid velocity through the media retainer 130 may be varied.

In some embodiments, the device 100 includes a liquid flow sensor configured to sense one or both of a fluid flow rate or a fluid flow rate through the media holder 130. In various other embodiments, device 100 does not include a liquid flow sensor, and processing system 142 may be configured to calculate a liquid flow rate and/or flow rate through media holder 130. As already described above, such calculation is typically based on the flow rate through the liquid flow circuit 10 and the linear velocity of the piston 124. The processing system 142 may obtain the flow rate of the liquid flow circuit 10 from data entered by a user through a user interface or from data obtained from the flow sensors 70, 71 of the liquid flow circuit 10 discussed above with reference to fig. 1 and 2. In some such examples, the flow sensors 70, 71 are in data communication with a processing system 142 configured to receive flow rate data from the flow sensors 70, 71 of the flow circuits 10, 11 (fig. 1 and 2). Processing system 142 is depicted in fig. 3 as being separate from controller 140, but in some embodiments processing system 142 is a component of controller 140. In some embodiments consistent with fig. 3, processing system 142 may be, for example, a computer in communication with controller 140.

In some embodiments, the controller 140 may be in operable communication with the actuator 120 such that the controller 140 is configured to operate the actuator (thereby translating the movable sidewall 124) to define a liquid flow rate condition through the media holder 130. The liquid flow rate conditions may be assigned to the system by a user through a user interface such as a computer, dial, keyboard, touch screen, or the like. The liquid flow rate conditions may be consistent with the circulation flow conditions. The processing system 142 may be configured to determine the circulation speed of the piston to achieve a specified fluid flow rate condition and communicate operating instructions to the controller 140, which is configured to send control signals to the actuator 120. In various embodiments, the actuator 120 is configured to actuate the cyclical flow condition in response to receiving a control signal from the controller 140.

In some embodiments, removal of the media holders 30, 31 in the liquid flow circuit 10 will also result in removal of the pressure sensors 50, 51 (fig. 1 and 2). Thus, the circulation flow device 100 may include a first pressure sensor 136 disposed on an upstream side of the movable side wall 124 of the device 100, and a second pressure sensor 138 disposed on a second side of the movable side wall 124, such that a differential pressure across the filter media holder 130 may be calculated. In some embodiments, the system may be configured to calculate a liquid flow rate through media holder 130 based on the differential pressure data.

Various modifications may be made to the design depicted in fig. 3 consistent with the techniques disclosed herein. While the current design has a single flow inlet 112 and a single flow outlet 114, in some embodiments, there may be multiple inlets 112 and multiple outlets 114 to the housing 110. The plurality of inlets 112 and the plurality of outlets 114 may extend from multiple directions to the housing 110. For example, multiple inlets extending to and from the housing may advantageously increase the speed at which the fluid flow rate may be varied. Further, in some embodiments, the inlet and outlet may extend from the housing in an axial direction rather than a lateral direction as depicted in the figures.

Fig. 4 is a schematic cross-sectional view of another example circulation flow device 200 consistent with the techniques disclosed herein. The circulation flow device 200 has a housing 210 defining a first variable volume 216. The housing 210 has a movable sidewall 224 defining a first variable volume 216. The housing 210 has a first flow opening 212 extending to a first variable volume 216. The conduit coupling 213 is disposed about the first flow opening 212. The conduit coupling 213 is configured to sealably couple to the liquid flow circuit 10 and may have a configuration similar to the conduit coupling discussed above. In the present example, the conduit coupling 213 is configured to couple to the inlet line 12 of the liquid flow circuit 10. However, it should be understood that in some embodiments, the conduit coupling 213 is configured to be coupled to the outlet line 14 of the liquid flow circuit 10 and will operate consistent with this description. In some other embodiments, the circulation flow device 200 is configured to be integral with the liquid flow circuit 10. In some (but not all) such embodiments, the circulation flow device 200 may omit the conduit coupling 213, wherein the liquid flow circuit 10 is integral with the housing 110.

The circulation flow device 200 is configured to vary the flow rate of liquid through the media holder 30. The circulation flow device 200 is generally configured to modify the fluid flow through the inlet line 12 (or outlet line) of the liquid flow circuit 10 to regulate the liquid flow rate through the media retainer 30 of the liquid flow circuit 10. The circulation flow device 200 may be configured to create a circulation flow condition through the media holder 30. In various embodiments, the circulation flow device 200 is configured to circulate a liquid flow rate through the media holder 30. In the present example, the media holder 30 is not defined by the circulation flow device 200. In contrast, here, the media retainer 30 is a component of the liquid flow circuit 10 (only a portion of which is currently depicted) to which the circulation flow device 200 is configured to be coupled.

In the present example, the circulation flow device 200 may operate as an accumulator. The circulation flow device 200 is configured to be fluidly coupled to the liquid flow circuit 10 upstream of the media holder 30. In various embodiments, the circulation flow device 200 is configured to cyclically accumulate liquid from the inlet line 12 of the liquid flow circuit 10 in the housing 210 (specifically, the first variable volume 216) and release liquid from the housing 210 (e.g., the first variable volume 216) to the inlet line 12 of the liquid flow circuit 10. After passing through the media retainer 30, the liquid passes through the outlet line 14 of the liquid flow circuit 10.

In the present example, the circulation flow device 200 is not coupled to the outlet line 14 of the liquid flow circuit 10, but in some other embodiments, the circulation flow device 200 is configured to be coupled to the outlet line 14 of the liquid flow circuit 10. In such embodiments, the circulation flow device 200 is configured to cyclically accumulate liquid from the outlet line 14 of the liquid flow circuit 10 in the housing 210 and release liquid from the housing 210 to the outlet line 14 of the liquid flow circuit 10. In such embodiments, the flow rate through the media holder 30 will generally decrease when liquid is released from the housing 210, and the flow rate through the media holder 30 will increase when liquid accumulates in the housing 210.

The housing 210 has a first flow opening 212 and a cavity 211 extending from the first flow opening 212. The cavity 211 extends in an axial direction from the first flow opening 212 toward the opposite axial end 202 of the housing 210. In the present example, the first flow opening 212 is a flow inlet, which means that liquid enters the housing through the first flow opening 212. In the present example, the first flow opening 212 is also a flow outlet, which means that liquid leaves the housing 210 through the first flow opening 212. The first flow opening 212 extends to a first variable volume 216.

The movable sidewall 224 is a piston 224 disposed across the cavity 211. The piston 224 forms a fluid tight seal with the inner surface of the housing 210. The piston 224 is linearly translatable in an axial direction along the cavity 211. Thus, the position of the piston 224 within the cavity 211 defines the volume of the first variable volume 216. The complementary variable volume 218 is defined on the opposite side of the piston 224, but unlike the previous embodiments, here the complementary variable volume 218 does not receive liquid from the liquid flow circuit 10. In further contrast to the previous embodiments, the piston 224 does not define a media holder. Instead, the media retainer 30 is a component of the liquid flow circuit 10.

The actuator 220 is generally operably coupled to the movable sidewall 224. In the present example, the actuator 220 is translatably coupled to a piston 224 via a shaft 222. In various embodiments, actuator 220 is a linear actuator secured to piston 224. The actuator 220 is configured to actuate linear translation of the piston 224 through the cavity 211. More particularly, actuator 220 is configured to cyclically translate piston 224 between a first position and a second position in cavity 211. The direction and speed of the piston 224 through the cavity 211 is related to the speed of fluid flow through the media retainer 30 in the liquid flow circuit 10. The actuator 220 and the movable sidewall 224 are configured to vary the flow rate of the liquid in the liquid flow circuit 10.

More particularly, the circulation flow device 200 is configured to be fluidly coupled to a liquid flow circuit 10 that circulates liquid therethrough at a constant volumetric flow rate. When the movable sidewall 224 is stationary within the cavity 211, the velocity of the liquid through the media holder 30 (or through the filter media coupled to the media holder around the media opening in the media holder) is constant and equal to the volumetric flow rate divided by the flow area of the opening in the media holder 30. As the movable sidewall 224 translates linearly through the cavity 211 away from the first flow opening 212, liquid is diverted from the liquid flow circuit 10 to the first variable volume 216. Thus, the volumetric flow rate toward the media holder 30 reduces the volumetric flow rate of liquid moving into the first variable volume 216 of the housing 210, thereby reducing the velocity of liquid passing through the media holder 30. As the movable sidewall 224 translates linearly through the cavity 211 toward the first flow opening 212, liquid is released from the first variable volume 216 to the liquid flow circuit 10. Thus, the volumetric flow rate through the media retainer 30 increases the volumetric flow rate of liquid exiting the housing 210. In this way, the fluid velocity of the sample filter media held across the media holder 30 can be varied.

In some embodiments, the circulation flow device 200 has a flow sensor 234 configured to sense a liquid flow rate. For example, the flow sensor 234 may be coupled to the housing 210 proximate the first flow opening 212 to sense a liquid flow rate through the first flow opening 212. In some other embodiments, the flow sensor 234 of the device 200 may be coupled to the media holder 30 in the liquid flow circuit 10. In embodiments that include a flow sensor 234, for example, the flow sensor 234 may communicate with a user interface to record the liquid flow rate and report the liquid flow rate to a user. In various examples, the flow sensor 234 is in data communication with a controller 240. The controller 240 may be in operable communication with the actuator 220 such that the controller 240 is configured to operate the actuator (and thereby translate the movable sidewall 224) to define a liquid flow rate relative to the flow sensor, and more particularly, the liquid flow rate through the media holder 30. In various embodiments, the circulation flow device 200 does not have a flow sensor 234. In some embodiments, the flow sensor may be a component of the liquid flow circuit 10, as discussed above. In some embodiments, the system is configured to calculate the flow rate through the media holder 30 based on the liquid flow rate through the liquid flow circuit (determined by the flow sensor or entered by the user) along with the liquid flow rate to or from the device 200 based on the expansion or contraction of the first variable volume 216 in response to the displacement of the piston 224.

In the present example configuration, the circulation flow device 200 does not replace any of the components of the liquid flow circuit 10 (such as in the case of the example of fig. 3, the device is configured to replace the media holder and possibly other components). In contrast, in the present example, the circulation flow device 200 is configured to be added to the liquid flow circuit 10.

Fig. 5 is a schematic cross-sectional view of yet another example circulation flow device 300. The circulation flow device 300 is similar to the circulation flow device described above with reference to fig. 4, except that in the present example, the first variable volume 316 of the housing 310 is configured to be in fluid communication with the liquid flow circuit 10 upstream of the media holder 30, and the complementary variable volume 318 of the housing 310 is configured to be in fluid communication with the liquid flow circuit 10 downstream of the media holder 30. The first variable volume 316 of the housing 310 is configured to be in fluid communication with the inlet line 12 of the liquid flow circuit 10, and the complementary variable volume 318 of the housing 310 is configured to be in fluid communication with the outlet line 14 of the liquid flow circuit 10. The circulation flow device 300 may be described as being parallel to the media holder 30. Such a configuration advantageously facilitates modification or circulation of the fluid velocity through the media holder 30 without significantly altering the volumetric flow through the liquid circuit upstream and downstream of the circulating flow apparatus 300. For example, as the first variable volume 316 increases to decrease the flow volume through the media retainer 30, the complementary variable volume 318 decreases to release a corresponding volume of liquid.

The housing 310 generally has a first flow opening 312, a second flow opening 314, and a cavity 311 extending from the first flow opening 312 to the second flow opening 314. The circulation flow device 300 has a housing 310 defining a first variable volume 316. The housing 310 has a movable sidewall 324 defining a first variable volume 316 and a complementary variable volume 318. The housing 310 has a first flow opening 312 extending to a first variable volume 316 and a second flow opening 314 extending to a complementary variable volume 318. First and second flow openings 312, 314 are defined on opposite axial ends of the housing 310. In the present example, each of the first and second flow openings 312, 314 operates as a flow inlet and a flow outlet for the housing 310.

The circulation flow device 300 is generally configured to vary the flow rate of liquid through the media holder 30. The circulation flow device 300 may be configured to create a circulating liquid flow condition through the media holder 30. In various embodiments, the circulation flow device 300 is configured to circulate a liquid flow rate through the media coupling structure 30. Similar to the example discussed with reference to fig. 4, in the present example, the media retainer 30 is not a component of the circulation flow device 300. Instead, the media holder 30 is a component of the liquid flow circuit 10 to which the circulation flow device 300 is configured to be coupled.

The movable sidewall 324 is a piston 324 disposed across the cavity 311. The piston 324 forms a fluid tight seal with the inner surface of the housing 310. The piston 324 is generally linearly translatable in an axial direction along the bore 311. Thus, the position of the piston 324 within the cavity 311 defines the volume of the first variable volume 316 and the volume of the complementary variable volume 318 on the opposite side of the piston 324.

The actuator 320 is translatably coupled to the movable sidewall 324. In the present example, the actuator 320 is fixed to the piston 324 via a shaft 322. In various embodiments, actuator 320 is a linear actuator secured to piston 324. The actuator 320 is configured to actuate linear translation of the piston 324 through the cavity 311. More particularly, the actuator 320 is configured to cyclically translate the piston 324 between a first position and a second position in the cavity 311. The direction and speed of the piston 324 through the cavity 311 may define the speed of fluid flow through the media holder 30, and more particularly, the speed of fluid flow through the filter media secured to the media holder 30. The actuator 320 may be configured to cause the housing to cyclically accumulate liquid from the inlet line 12 of the liquid flow circuit 10 in the first variable volume 316 and release liquid from the first variable volume 316 to the inlet line 12 of the liquid flow circuit 10.

The circulation flow device 300 generally has a first conduit coupling 313 surrounding the first flow opening 312 that is configured to be sealably coupled to the liquid flow circuit 10 such that the first flow opening 312 is in direct fluid communication with the inlet line 12 of the liquid flow circuit 10. In various embodiments, the first conduit coupling 313 is configured to be detachably coupled to the inlet line 12 of the liquid flow circuit 10. The circulation flow device 300 also has a second conduit coupling 315 surrounding the second flow opening 314, the second conduit coupling configured to be sealably coupled to the outlet line 14 of the liquid flow circuit such that the second flow opening 314 is in direct fluid communication with the outlet line 14 of the liquid flow circuit 10. The second conduit coupling 315 is configured to be detachably coupled to the outlet line 14 of the liquid flow circuit 10. In some other embodiments, the circulation flow device 300 is configured to be integral with the liquid flow circuit 10. In some (but not all) such embodiments, the circulating flow apparatus 300 may omit one or both of the first conduit coupling 313 and the second conduit coupling 315, with the inlet line 12 and/or the outlet line 14 being integral with the housing 110.

As already discussed, the liquid flow circuit 10 coupled to the circulation flow device 300 is generally configured to circulate liquid through the flow circuit at a constant volumetric flow rate. When the movable sidewall 324 is stationary within the cavity 311, the velocity of the liquid passing through the opening of the media holder 30 (or through the filter media coupled to the media holder) is constant and equal to the volumetric flow rate divided by the flow area of the opening in the media holder 30. As the movable sidewall 324 translates linearly through the cavity 311 away from the first flow opening 312, liquid from the inlet line 12 of the liquid flow circuit 10 accumulates in the first variable volume 316. The volumetric flow rate through the inlet line 12 reduces the volumetric flow rate of liquid into the first variable volume 316 of the housing 310, thereby reducing the velocity of the liquid through the media retainer 30. At the same time, the liquid within the complementary variable volume 318 is released in the outlet line 14 of the liquid flow circuit 10.

As the movable sidewall 324 translates linearly through the cavity 311 toward the first flow opening 312, liquid from the first variable volume 316 of the housing 310 is released to the inlet line 12 of the liquid flow circuit 10. The volumetric flow rate through the inlet line 12 increases the volumetric flow rate of the liquid exiting the first variable volume 316 of the housing 310, thereby increasing the velocity of the liquid through the media retainer 30. At the same time, the complementary variable volume 318 accumulates liquid from the outlet line 14 of the liquid flow circuit 10. The volumetric flow rate through the outlet line 14 correspondingly reduces the volumetric flow rate of liquid into the complementary variable volume 318 of the housing 310.

In the manner described above, the fluid velocity of the sample filter media held across the media holder 30 may be cyclically varied.

As already discussed above, the circulation flow device 300 may have a flow sensor 334 configured to sense the liquid flow rate. The flow sensor 334 may be configured to sense a liquid flow rate through the first flow opening 312 or elsewhere, as already described above. The flow sensor 334 may be in communication with the user interface, the controller 340, or both the user interface and the controller 340. The controller 340 may be in operable communication with the actuator 320, as already described above.

Fig. 6 is a schematic cross-sectional view of yet another example circulating flow apparatus. Similar to the example discussed above with reference to fig. 5, here, the first variable volume 416 of the housing 410 is configured to be in fluid communication with the liquid flow circuit 10 upstream of the media retainer 30, and the complementary variable volume 418 of the housing 410 is configured to be in fluid communication with the liquid flow circuit 10 downstream of the media retainer 30. However, in the present example, the first variable volume 416 of the housing 410 is configured to be mounted in-line with the inlet line 12 of the liquid flow circuit 10, and the complementary variable volume 418 of the housing 410 is in fluid communication with the outlet line 14 of the liquid flow circuit 10. More specifically, a complementary variable volume 418 of the housing 410 is fed into the outlet line 14 of the liquid flow circuit 10. Such a configuration may advantageously facilitate modification or circulation of the fluid velocity through the media holder 30 without altering the volumetric flow through the liquid circuit upstream and downstream of the circulating flow apparatus 400.

The housing 410 generally has a first flow opening 412, a second flow opening 414, and a cavity 411 extending from the first flow opening 412 to the second flow opening 414. The housing 410 of the circulation flow device 400 defines a first variable volume 416 and a complementary variable volume 418. The housing 410 has a movable sidewall 424 defining a first variable volume 416 and a complementary variable volume 418. The housing 410 has a first flow opening 412 extending to a first variable volume 416 and a second flow opening 414 extending to a complementary variable volume 418. First and second flow openings 412, 414 are defined on opposite axial ends of the housing 410. In the present example, the first flow opening 412 operates as a flow outlet to the housing 410. The first flow opening 412 is not a flow inlet. The second flow opening 414 operates as a flow inlet and a flow outlet to the housing 410.

A first conduit coupling 413 is disposed about the first flow opening 412, the first conduit coupling configured to be sealably coupled to the liquid flow circuit 10 such that the first flow opening 412 is in direct fluid communication with the inlet line 12 of the liquid flow circuit 10. In various embodiments, the first conduit coupling 413 is configured to be detachably coupled to the inlet line 12 of the liquid flow circuit 10. A second conduit coupling 415 is disposed about the second flow opening 414, the second conduit coupling configured to be sealably coupled to the outlet line 14 of the liquid flow circuit such that the second flow opening 414 is in direct fluid communication with the outlet line 14 of the liquid flow circuit 10. The second conduit coupling 415 is configured to be detachably coupled to the outlet line 14 of the liquid flow circuit 10.

Similar to some previous examples, here, the movable sidewall 424 is a piston 424 disposed across the cavity 411 that defines a first variable volume 416 and a complementary variable volume 418 of the housing 410. Piston 424 forms a fluid tight seal with the inner surface of housing 410. The piston 424 is generally linearly translatable in an axial direction along the cavity 411. Thus, the position of the piston 424 within the cavity 411 defines the volume of the first variable volume 416 and the volume of the complementary variable volume 418 on the opposite side of the piston 424.

The actuator 420 is translatably coupled to a piston 424 via a shaft 422. In various embodiments, actuator 420 is a linear actuator secured to piston 424. The actuator 420 is configured to actuate linear translation of the piston 424 through the cavity 411. More particularly, the actuator 420 is configured to cyclically translate the piston 424 between a first position and a second position in the cavity 411. The direction and speed of the piston 424 through the cavity 411 may define the speed of fluid flow through the media retainer 30, and more particularly, the speed of fluid flow through the filter media secured to the media retainer 30. The actuator 420 may be configured to cause the housing 410 to cyclically accumulate liquid from the inlet line 12 of the liquid flow circuit 10 in the first variable volume 416 and release liquid from the first variable volume 416 to the inlet line 12 of the liquid flow circuit 10.

Unlike the previous examples, in the present example, the housing 410 has a third flow opening 419 configured to fluidly couple to the inlet line 12 of the liquid flow circuit 10. The third flow opening 419 is configured to be positioned along the inlet line 12 of the liquid flow circuit 10 upstream of the first flow opening 412. The third conduit coupling 417 surrounding the third flow opening 419 is configured to sealably couple to the inlet line 12 of the liquid flow circuit 10. The third conduit coupling 417 may be consistent with other conduit coupling structures described herein. It should be noted that, similar to the examples described above, in some embodiments in which the circulating flow apparatus is integral with the fluid flow circuit 10, one or more of the conduit coupling 413, 415, 417 may be omitted.

The first variable volume 416 is configured to fluidly couple the inlet line 12 and the media retainer 30. First flow opening 412 and third flow opening 419 are in direct fluid communication with first variable volume 416. Specifically, in the present example, piston 424 and shaft 422 define a liquid conduit 426 that fluidly couples third flow opening 419 and first variable volume 416. In this example, the liquid conduit 426 passes through the complementary variable volume 418, but is fluidly isolated from the complementary variable volume 418. In operation, the liquid flow circuit 10 may be configured to direct a flow of liquid through the liquid conduit 426 at a constant volumetric flow rate.

As with the previously described embodiments, the circulation flow device 400 is configured to vary the liquid flow rate through the media holder 30. The circulation flow device 400 may be configured to create a circulating liquid flow condition through the media holder 30. In various embodiments, the circulation flow device 400 is configured to circulate a liquid flow rate through the media coupling structure 30.

As already described above, when the movable sidewall 424 is stationary within the cavity 411, the velocity of the liquid passing through the media holder 30 (or through the filter media coupled to the media holder 30) is constant and equal to the volumetric flow rate of the liquid flow circuit 10 divided by the flow area of the opening in the media holder 30. As the movable sidewall 424 translates linearly through the cavity 411 away from the first flow opening 412, the volumetric flow rate decreases the volumetric flow rate of liquid into the first variable volume 416, thereby decreasing the velocity of liquid through the media holder 30. As the movable sidewall 424 translates linearly through the cavity 411 toward the first flow opening 412, the volumetric flow rate through the first flow opening 412 increases the volumetric flow rate of liquid pushed out of the first variable volume 416 by the piston, thereby increasing the velocity of liquid through the media holder 30.

In various embodiments, a flexible hose may fluidly couple the liquid conduit 426 of the shaft 422 and the inlet line 12 to accommodate linear translation of the piston 424 (and thus the shaft 422).

As already discussed above, the circulation flow device 400 may have a flow sensor 434 configured to sense a liquid flow rate. The flow sensor 434 may be configured to sense the flow rate of liquid through the first flow opening 412 or elsewhere, as already described above. The flow sensor 434 may be in communication with a user interface, a controller 440, or both a user interface and a controller 440. The controller 440 may be in operative communication with the actuator 420, as already described above.

Although in the present example, the apparatus 400 has a first variable volume 416 coupled to the inlet line 12 just upstream of the media holder 30, in some other embodiments, the first variable volume 416 is coupled to the outlet line 14 downstream of the media holder 30. In such a configuration, the first variable volume 416 of the housing 410 is configured to be in fluid communication with the liquid flow circuit 10 downstream of the media retainer 30, and the complementary variable volume 418 of the housing 410 is configured to be in fluid communication with the liquid flow circuit 10 along the inlet line 12 upstream of the media retainer 30. In such an example, the first variable volume 416 of the housing 410 may be configured to be mounted in-line with the outlet line 14 of the liquid flow circuit 10, and the complementary variable volume 418 of the housing 410 may be configured to be fed into the inlet line 12 of the liquid flow circuit 10.

It should be noted that in the embodiments depicted and described above, displacement of a first volume of liquid from a first variable volume by a piston results in an opposite displacement of a corresponding volume of liquid from a complementary variable volume, wherein the corresponding volume is smaller than the first volume of liquid. The reason for this is that the shaft reduces the volume of the complementary variable volume compared to the first variable volume. Fig. 7 is a schematic cross-sectional view of an alternative exemplary variable volume housing 510 consistent with some embodiments, wherein the configuration of the housing 510 advantageously equalizes the volumes per unit length of the first variable volume 516 and the complementary variable volume 518. The housing 510 may replace other housings disclosed in the present disclosure and may be configured to define openings and flow paths consistent with embodiments that have been disclosed.

The housing 510 has a first end 502 and a second end 504, and a fluid flow passage 511 extending axially from the first end 502 to the second end 504. A movable sidewall 524 is disposed in the fluid flow passageway 511. A first variable volume 516 and a complementary variable volume 518 are defined within the housing 510 on opposite sides of the movable side wall 524. The movable side wall 524 is a piston 524. The first shaft 522 is configured to couple the piston 524 to an actuator (not currently depicted). The first shaft 522 extends in an axial direction through the second end 504 of the housing 510 and through the complementary variable volume 518. A second shaft 526 is coupled to the piston 524 opposite the first shaft 522. The second shaft 526 extends through the first end 502 of the housing 510 and through the first variable volume 516. In various embodiments, the cross-sectional areas of the first shaft 522 and the second shaft 526 are equal, where the cross-sectional areas are orthogonal to the axial extension of the housing 510.

Fig. 8 is a schematic cross-sectional view of yet another example circulation flow device 600 consistent with various embodiments. The circulation flow device 600 is configured to be coupled to the liquid flow circuit 10. The circulation flow device 600 has a housing 610 defining a first flow opening 612 and a first conduit coupling 613 surrounding the first flow opening 612. The first conduit coupling 613 is configured to be detachably coupled to the liquid flow circuit 10. The actuator 620 is in operative communication with the housing 610. The actuator 620 is configured to cyclically accumulate liquid in the liquid flow circuit 10 to the housing 610 (and in particular, the first variable volume 616) and release liquid from the housing 610 (and in particular, the first variable volume 616) to the liquid flow circuit 10. In some embodiments, a flow sensor 634 is positioned adjacent to the first flow opening 612. In particular, here, a flow sensor 634 is positioned near the bladder outlet 612 (where the bladder is described in more detail below). The flow sensor 634 may be configured to sense the flow rate of liquid through the first flow opening 612 or elsewhere, as already described above. Flow sensor 634 may be in communication with a user interface, controller 640, or both a user interface and controller 640. The controller 640 may be in operable communication with the actuator 620 and in data communication with the flow sensor 634 to vary the flow rate of the liquid through the first flow opening 612.

In the present example, the housing 610 defines a cavity 611 having a first variable volume 616 and a complementary variable volume 618. The first variable volume 616 is configured to be coupled collinearly with the inlet line 12 of the liquid flow circuit 10. The first variable volume 616 is connected in series between the inlet line 12 and the media retainer 30. Thus, the first variable volume 616 has a first conduit coupling 613 configured to couple to the liquid flow circuit 10 upstream of the media retainer 30 and a second conduit coupling 617 surrounding the second flow opening 619 configured to couple to the liquid flow circuit 10 upstream of the first conduit coupling 613.

The complementary variable volume 618 is configured to be coupled collinearly with the outlet line 14 of the liquid flow circuit 10. A complementary variable volume 618 is connected in series between the media retainer 30 and the outlet line 14. Thus, the housing 610 has a third conduit coupling 615 surrounding a third flow opening 614 that communicates with a complementary variable volume 618. The third conduit coupling 615 is configured to be coupled to the liquid flow circuit 10 downstream of the media retainer 30. The housing 610 has a fourth conduit coupling 621 surrounding a fourth flow opening 623 in communication with the complementary variable volume 618. The fourth conduit coupling 621 is configured to couple to the liquid flow circuit 10 upstream of the third conduit coupling 615. Similar to the examples described above, in some embodiments in which the circulation flow device is integral with the fluid flow circuit 10, one or more of the conduit coupling structures 613, 615, 617, 621 may be omitted.

Similar to other embodiments described herein, the housing 610 has a movable sidewall 624 defining a first variable volume 616. However, unlike the previous examples, in the present example, movable sidewall 624 is a bladder 624. Bladder 624 is typically constructed of a hollow flexible material, such as an elastomeric material, such as rubber. In some other embodiments, the movable sidewall may be a bellows having a collapsible and expandable sidewall. The first flow opening 612 of the bladder 624 may be referred to as a bladder outlet 612. The second flow opening 619 of the bladder 624 may be referred to as a bladder inlet 619. The bladder outlet 612 extends from the first variable volume 616, and the bladder inlet 619 extends to the first variable volume 616.

In the present example, the housing 610 has a casing 644 that houses a bladder 624. The housing 644 is generally rigid to define a fixed volume. The complementary variable volume 618 is defined by the volume between the bladder 624 and the inner surface of the housing 644. Such a configuration may advantageously allow liquid accumulated by the first variable volume 616 to replace liquid accumulated by the complementary variable volume 618. The third flow opening 614 and the fourth flow opening 623 are defined by a housing 644. The third flow opening 614 may be referred to as a housing outlet 614 and the fourth flow opening 623 may be referred to as a housing inlet 623. In the present configuration, the housing inlet 623 and the bladder inlet 619 are located on opposite axial ends of the housing 610. Similarly, the housing outlet 614 and bladder outlet 612 are located on opposite axial ends of the housing 610.

In the present example, actuator 620 is operably coupled to movable sidewall 624. In particular, a flow control valve 636 is coupled to the bladder 624 across the bladder outlet 612, and an actuator 620 is operatively coupled to the flow control valve 636. The actuator 620 is configured to selectively oscillate the valve 636 between the restricting position and the open position to reduce and increase the flow rate of the liquid through the first flow opening 612 and, thus, the media holder 30. Decreasing the flow rate of the liquid through the first flow opening 612 causes the bladder 624 to retain the liquid from the inlet line 12 of the liquid flow circuit 10, and the bladder 624 expands to contain an increased volume of liquid in the bladder. Increasing the flow rate of the liquid through the first flow opening 612 causes the bladder 624 to release the liquid into the liquid flow circuit 10 and causes the bladder to contract as the volume of liquid within the bladder 624 decreases.

Fig. 9 is a schematic cross-sectional view of yet another example circulation flow device. Similar to the example discussed above with reference to fig. 8, here the first variable volume 716 of the housing 710 is configured to be collinear with the inlet line 12 of the liquid flow circuit 10, and the complementary variable volume 718 of the housing 710 is configured to be in fluid communication with the outlet line 14 of the liquid flow circuit 10. Configuring both the first variable volume 716 and the complementary variable volume 718 to be collinear with the flow lines in the liquid flow circuit may advantageously allow the fluid flow through these volumes to be constant, thereby reducing the accumulation or settling of particles in these volumes. In the present example, the first variable volume 716 of the housing 710 is configured to be mounted in-line with the inlet line 12 of the liquid flow circuit 10, and the complementary variable volume 718 of the housing 710 is in fluid communication with the outlet line 14 of the liquid flow circuit 10. This configuration advantageously facilitates modification or circulation of the fluid velocity through the media retainer 30 without altering the volumetric flow through the liquid flow circuit 10 upstream and downstream of the circulation flow device 700.

The housing 710 generally has a first flow opening 712, a second flow opening 714, and a cavity 711 extending from the first flow opening 712 to the second flow opening 714. The housing 710 of the circulation flow device 700 defines a first variable volume 716 and a complementary variable volume 718. The housing 710 has a movable side wall 724 defining a first variable volume 716 and a complementary variable volume 718. The housing 710 has a first flow opening 712 extending to a first variable volume 716 and a second flow opening 714 extending to a complementary variable volume 718. A first flow opening 712 and a second flow opening 714 are defined on opposite axial ends of the housing 710. In the present example, the first flow opening 712 operates as a flow outlet to a first variable volume 716 of the housing 710. The first flow opening 712 is not a flow inlet. The second flow opening 714 operates as a flow outlet to a complementary variable volume 718 of the housing 710.

A first conduit coupling 713 is disposed about the first flow opening 712, the first conduit coupling being configured to be sealably coupled to the liquid flow circuit 10 such that the first flow opening 712 is in direct fluid communication with the inlet line 12 of the liquid flow circuit 10. In various embodiments, the first conduit coupling 713 is configured to be detachably coupled to the inlet line 12 of the liquid flow circuit 10. A second conduit coupling 715 is disposed about the second flow opening 714, the second conduit coupling configured to be sealably coupled to the outlet line 14 of the liquid flow circuit such that the second flow opening 714 is in direct fluid communication with the outlet line 14 of the liquid flow circuit 10. The second conduit coupling 715 is configured to be detachably coupled to the outlet line 14 of the liquid flow circuit 10.

The housing 710 has a third flow opening 719 configured to be fluidly coupled to the inlet line 12 of the liquid flow circuit 10. The first flow opening 712 and the third flow opening 719 are in direct fluid communication with the first variable volume 716. The third flow opening 719 is configured to be located upstream of the first flow opening 712 along the inlet line 12 of the liquid flow circuit 10. The third flow opening 719 operates as an inlet to the first variable volume 716. The third conduit coupling 717 surrounding the third flow opening 719 is configured to sealably couple to the inlet line 12 of the liquid flow circuit 10. The third conduit coupling 717 may be consistent with other conduit coupling described herein.

The housing 710 has a fourth flow opening 723 configured to be fluidly coupled to the outlet line 14 of the liquid flow circuit 10. The fourth flow opening 723 is configured to be located along the outlet line 14 of the liquid flow circuit 10 upstream of the second flow opening 714. The second flow opening 714 and the fourth opening 723 are in direct fluid communication with the complementary variable volume 718. The fourth flow opening 723 operates as an inlet to the complementary variable volume 718. The fourth conduit coupling 721 surrounding the fourth flow opening 723 is configured to be sealably coupled to the outlet line 14 of the liquid flow circuit 10. The fourth conduit coupling 721 may be consistent with other conduit coupling structures described herein. Similar to the examples described above, in some embodiments in which the circulation flow device is integral with the fluid flow circuit 10, one or more of the conduit coupling structures 713, 715, 717, 721 may be omitted.

Similar to some previous examples, here, the movable side wall 724 is a piston 724 disposed across the fluid channel 711, the piston defining a first variable volume 716 and a complementary variable volume 718 of the housing 710. The piston 724 forms a fluid-tight seal with the interior surface of the housing 710. The piston 724 is generally linearly translatable in an axial direction along the cavity 711. Thus, the position of the piston 724 within the cavity 711 defines the volume of the first variable volume 716 and the volume of the complementary variable volume 718 on the opposite side of the piston 724.

The actuator 720 is translatably coupled to a piston 724 via a shaft 722. In various embodiments, actuator 720 is a linear actuator that is fixed to piston 724. The actuator 720 is configured to actuate linear translation of the piston 724 through the cavity 711. More particularly, the actuator 720 is configured to cyclically translate the piston 724 between a first position and a second position in the cavity 711. The direction and speed of the piston 724 through the cavity 711 may define the speed of fluid flow through the media holder 30, and more particularly, the speed of fluid flow through the filter media secured to the media holder 30.

As with the previously described embodiments, the circulation flow device 700 is configured to vary the liquid flow rate through the media holder 30. The circulation flow device 700 may be configured to create a circulating liquid flow condition through the media holder 30. In various embodiments, the circulation flow device 700 is configured to circulate a liquid flow rate through the media coupling structure of the media holder 30.

In various embodiments, the liquid flow circuit 10 coupled to the circulation flow device 700 is configured to circulate liquid through the flow circuit at a constant volumetric flow rate. Thus, when the movable sidewall 724 is stationary within the cavity 711, the velocity of the liquid passing through the media holder 30 (or through the filter media coupled to the media holder 30) is constant and equal to the volumetric flow rate divided by the flow area of the openings in the media holder 30. As the movable sidewall 724 translates linearly through the cavity 711 away from the first flow opening 712, the volumetric flow rate through the first flow opening 712 decreases the volumetric flow rate of liquid into the first variable volume 716, thereby decreasing the velocity of liquid through the media retainer 30. As the movable sidewall 724 translates linearly through the cavity 711 toward the first flow opening 712, the volumetric flow rate through the first flow opening 712 increases the volumetric flow rate of liquid pushed out of the first variable volume 716 by the piston, thereby increasing the velocity of liquid through the media holder 30.

As already discussed above, the circulation flow device 700 may have a flow sensor 734 configured to sense a liquid flow rate. The flow sensor 734 may be configured to sense a liquid flow rate through the first flow opening 712 or elsewhere, as already described above. Flow sensor 734 may be in communication with a user interface, controller 740, or both a user interface and controller 740. The controller 740 may be in operable communication with the actuator 720, as already described above.

In various embodiments of the presently disclosed technology, the system is configured to oscillate the first variable volume between a minimum possible volume of the first variable volume and another volume. Such a system configuration reduces the chance of contaminants suspended in the liquid remaining in the first variable volume and thus ensures that contaminants pass through the liquid flow circuit downstream of the first variable volume. Similarly, in embodiments where there is a complementary variable volume in liquid communication with the liquid flow circuit (such as depicted in fig. 3, 5, 6, 8, and 9), various embodiments of the systems disclosed herein are configured to oscillate the complementary variable volume between its smallest possible volume and another volume for the same reasons. Because the smallest possible volume of the complementary variable volume results in the largest possible volume of the first variable volume and the smallest possible volume of the first variable volume results in the largest possible volume of the complementary variable volume, such a system is configured to oscillate the first variable volume (and the complementary variable volume) between its smallest possible volume and the largest possible volume.

For example, in embodiments where the first variable volume and the complementary variable volume are defined by a cylinder and a piston translatably disposed in the cylinder (such as depicted in fig. 3, 5, 6, 7, and 9), the system is configured to oscillate the piston between axial ends of the cylinder such that a minimum volume of the first variable volume approaches zero, and a maximum volume of the first variable volume approaches a volume of the cylinder less the volume of the piston when the complementary variable volume approaches zero. As another example, in an embodiment where the first variable volume is defined by a bladder and the complementary variable volume is defined by a housing (such as depicted in fig. 8), the smallest possible volume of the first variable volume 616 may be near zero when the internal volume of the bladder 624 is near zero, which correlates to the largest possible volume of the complementary variable volume 618, which is the volume of the housing minus the volume of the bladder 624. The minimum possible volume of the complementary variable volume 618 may be near zero, which corresponds to the bladder 624 expanding to its maximum possible volume, wherein the bladder 624 expands to substantially fill the housing 644.

In some embodiments of the current technology, it may be desirable to use different circulation devices with alternative configurations in combination with a particular liquid flow circuit. For example, some test conditions may benefit from a circulating flow apparatus having a relatively large first variable volume, while other test conditions may benefit from a circulating flow apparatus having a relatively small first variable volume. Thus, some systems consistent with the technology disclosed herein include multiple circulation devices, each coupled in parallel to a liquid flow circuit. Each circulation device may define a first variable volume (and a complementary variable volume, if relevant) of different size. Each circulation device may be consistent with those devices discussed herein. In such embodiments, the system may include a switch, such as an electronic or mechanical switch, by which each circulation device may be selected for operable engagement with the liquid flow circuit. In some such embodiments, the liquid communication between each circulation device and the liquid flow circuit is mutually exclusive.

Statement of embodiment

Example 1. A circulation flow device comprising:

A housing having a first variable volume and a first flow opening extending to the first variable volume, the housing including a movable sidewall defining the first variable volume, and the housing including a first conduit coupling surrounding the first flow opening; and

a linear actuator secured to the movable sidewall.

Embodiment 2. The circulation flow device of any one of claims 1 and 3 to 12, wherein the movable side wall is a piston.

Embodiment 3. The circulation flow device of any one of claims 1-2 and 4-12, wherein the linear actuator and the movable sidewall are configured to vary a flow rate of the liquid in the liquid flow circuit.

Embodiment 4. The circulating flow apparatus of any one of claims 1-3 and 5-12, wherein the first conduit coupling is configured to sealably couple to a liquid flow circuit.

Embodiment 5. The circulating flow apparatus of any one of claims 1-4 and 6-12 wherein the piston has a media opening defining a flow path in fluid communication with the first variable volume.

Embodiment 6. The circulating flow apparatus of any one of claims 1-5 and 7-12 wherein the piston comprises a media coupling structure surrounding the media opening.

Embodiment 7. The circulating flow apparatus of any one of claims 1-6 and 8-12 wherein the piston forms a fluid seal with the housing across the first variable volume.

Embodiment 8. The circulation flow device of any one of claims 1 to 7 and 9 to 12, wherein the first flow openings are a flow inlet and a flow outlet.

Embodiment 9. The circulation flow device of any one of claims 1 to 8 and 10 to 12, wherein the first flow opening is a flow inlet and the first flow opening is not a flow outlet.

Embodiment 10. The circulation flow device of any one of claims 1 to 9 and 11 to 12, the housing having a complementary variable volume, wherein the movable sidewall defines the complementary variable volume.

Embodiment 11. The circulation flow device of any one of claims 1 to 10 and 12, wherein the housing has a second flow opening extending to the complementary variable volume.

Embodiment 12. The circulation flow device of any one of claims 1 to 11, wherein the circulation flow device is a retrofit installation.

Example 13. A circulation flow device comprising:

a housing having a flow inlet, a flow outlet, and a cavity extending in an axial direction from the flow inlet to the flow outlet; and

a piston disposed across the cavity and forming a seal with the housing, wherein the piston is linearly translatable along the cavity in the axial direction, the piston defining an axially extending media opening in fluid communication with the cavity.

The circulation flow device of any one of claims 13 and 15 to 18, further comprising: an actuator coupled to the piston.

The circulation flow device of any one of claims 13-14 and 16-18, wherein the actuator is configured to cyclically translate the piston between a first position and a second position in the cavity.

The circulation flow device of any one of claims 13 to 15 and 17 to 18, wherein the first position is toward a first end of the cavity and the second position is toward a second end of the cavity.

Embodiment 17. The circulation flow device of any one of claims 13-16 and 18, wherein the piston defines a media coupling structure surrounding the media opening.

The circulation flow device of any one of claims 13 to 17, wherein the circulation flow device is a retrofit unit.

Example 19. A circulation flow device comprising:

a housing having a first variable volume, the housing defining a first flow opening and a conduit coupling surrounding the first flow opening, wherein the conduit coupling is configured to be detachably coupled to a liquid flow circuit; and

an actuator in operable communication with the housing, wherein the actuator is configured to cause the housing to cyclically accumulate liquid in the liquid flow circuit in the first variable volume and release liquid from the first variable volume to the liquid flow circuit.

Embodiment 20 the circulation flow device of any one of claims 19 and 21 to 27, further comprising: a flow sensor positioned in the first flow opening; and a controller coupled to the actuator, wherein the controller is in data communication with the flow sensor.

The circulation flow device of any one of claims 19 to 20 and 22 to 27, wherein the housing is a cylinder.

Embodiment 22 the circulation flow device of any one of claims 19 to 21 and 23 to 27, further comprising: a piston translatably disposed in the cylinder, wherein the first variable volume is defined by the cylinder and the piston.

Embodiment 23 the circulation flow device of any one of claims 19 to 22 and 24 to 27, further comprising: a complementary variable volume defined by the cylinder and the piston, wherein the cylinder defines a second flow opening extending to the complementary variable volume.

The circulation flow device of any one of claims 19 to 23 and 25 to 27, wherein the first variable volume is a bladder.

The circulation flow device of any one of claims 19 to 24 and 26 to 27, wherein the first flow openings are a flow inlet and a flow outlet.

The circulation flow device of any one of claims 19 to 25 and 27, wherein the first flow opening is a flow inlet and the first flow opening is not a flow outlet.

The circulation flow device of any one of claims 19 to 26, wherein the circulation flow device is a retrofit unit.

Example 28. A circulation flow device comprising:

a housing defining a first variable volume and a complementary variable volume, the housing comprising a housing having a fixed volume and a bladder disposed in the housing, wherein the bladder defines the first variable volume, a bladder inlet extending to the first variable volume, and a bladder outlet extending from the first variable volume, wherein the complementary variable volume is defined between the bladder and the housing, and the housing defines a housing inlet and a housing outlet;

a flow control valve operatively coupled to the bladder outlet; and

an actuator operably coupled to the flow control valve, wherein the actuator is configured to oscillate the flow control valve between a restricted position and an open position.

The circulation flow device of any one of claims 28 and 30 to 33, wherein the bladder inlet and the housing inlet are located at opposite axial ends of the housing.

Embodiment 30 the circulation flow device of any one of claims 28 to 29 and 31 to 33, further comprising: a flow sensor positioned near the bladder outlet; and a controller coupled to the actuator, wherein the controller is in data communication with the flow sensor.

Embodiment 31 the circulation flow device of any one of claims 28 to 30 and 32 to 33, further comprising: a first conduit coupling around the bladder outlet, a second conduit coupling around the housing outlet, a third conduit coupling around the bladder inlet, and a fourth conduit coupling around the housing inlet, wherein each conduit coupling is configured to couple to a liquid flow circuit.

The circulation flow device of any one of claims 28 to 31 and 33, wherein the actuator is configured to cyclically accumulate and release liquid from the bladder.

Embodiment 33 the circulation flow device of any one of claims 28 to 32, wherein the circulation flow device is a retrofit installation.

Example 34. A circulation flow device comprising:

a housing defining a first variable volume and a first flow opening extending to the first variable volume, the housing including a movable sidewall defining the first variable volume;

an actuator operably coupled to the movable sidewall;

a flow sensor configured to sense a liquid flow rate; and

A controller in data communication with the flow sensor and in operative communication with the actuator, wherein the controller is configured to operate the actuator to define a liquid flow rate relative to the flow sensor.

The circulation flow device of any one of claims 34 and 36 to 46, wherein the movable side wall includes a piston.

Embodiment 36 the circulating flow apparatus of any one of claims 34-35 and 37-46 wherein the piston defines an opening and a media coupling structure surrounding the opening.

The circulating flow apparatus of any one of claims 34-36 and 38-46, wherein the flow sensor is disposed on the piston.

The circulation flow device of any one of claims 34 to 37 and 39 to 46, wherein the flow sensor is disposed adjacent the first flow opening.

Embodiment 39. The circulating flow apparatus of any one of claims 34-38 and 40-46 wherein the actuator is a linear actuator.

Embodiment 40 the circulation flow device of any one of claims 34 to 39 and 41 to 46, wherein the actuator is configured to operate a flow control valve.

Embodiment 41 the circulating flow apparatus of any one of claims 34-40 and 42-46, the housing comprising a first conduit coupling surrounding the first flow opening, wherein the first conduit coupling is configured to sealably couple to a liquid flow circuit.

Embodiment 42 the circulation flow device of any one of claims 34 to 41 and 43 to 46, wherein the first flow openings are a flow inlet and a flow outlet.

Embodiment 43 the circulation flow device of any one of claims 34 to 42 and 44 to 46, wherein said first flow opening is a flow inlet and said first flow opening is not a flow outlet.

Embodiment 44. The circulating flow apparatus of any one of claims 34-43 and 45-46 the housing has a complementary variable volume, wherein the movable side wall defines the complementary variable volume.

Embodiment 45. The circulating flow apparatus of any one of claims 34-44 and 46 wherein the housing has a second flow opening extending to the complementary variable volume.

The circulation flow device of any one of claims 34 to 45, wherein the circulation flow device is a retrofit unit.

One or more of the components described herein, such as a controller, sensor, detector, or system, may include a processor, such as a Central Processing Unit (CPU), computer, logic array, or other device capable of directing data into and out of the components. A processor may include one or more computing devices with memory, processing, and communication hardware. The controller may include circuitry for coupling together various components of the controller or coupling together various components of the controller with other components operatively coupled to the controller. The functions of the processor may be performed by hardware and/or as computer instructions on a non-transitory computer-readable storage medium.

The processor may include any one or more of a microprocessor, a microcontroller, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some examples, a processor may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the processor herein may be embodied as software, firmware, hardware or any combination thereof.

In one or more embodiments, the functionality of the processor may be implemented using one or more computer programs using a computing device, which may include one or more processors and/or memory. Program code and/or logic described herein may be applied to input data/information to perform the functions described herein and to generate desired output data/information. The output data/information may be applied as input to one or more other devices and/or methods, as described herein or in a known manner. In view of the above, it is apparent that the controller functions described herein may be implemented in any manner known to those skilled in the art.

It should also be noted that, as used in this specification and the appended claims, the phrase "configured to" describes a system, apparatus, or other structure that is constructed to perform a particular task or take a particular configuration. The word "configured to" may be used interchangeably with terms such as "disposed to," "configured to," "manufactured to," and the like.

All publications and patent applications in this specification are indicative of the level of skill of those skilled in the art to which this application pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. In the event of any inconsistency between the present disclosure and the disclosure of any of the documents incorporated by reference herein, the present disclosure shall control.

This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive, and that the claims are not to be limited to the illustrative embodiments as set forth herein. For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers should be understood as modified in all instances by the term "about". Furthermore, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein that may or may not be specifically recited herein. Thus, in this context, the values recited herein encompass deviations of ±3 percentiles. In this context, the recited values may be regarded as values comprised within the general standard error of the property modified by the measurement number.

Claims

1. A circulation flow device comprising:

a linear actuator secured to the movable sidewall.

2. The circulation flow device of any one of claims 1 and 3 to 12, wherein the movable side wall is a piston.

3. The circulation flow device of any one of claims 1 to 2 and 4 to 12, wherein the linear actuator and the movable side wall are configured to vary a flow rate of liquid in a liquid flow circuit.

4. The circulation flow device of any one of claims 1 to 3 and 5 to 12, wherein the first conduit coupling is configured to sealably couple to a liquid flow circuit.

5. The circulating flow apparatus of any one of claims 1-4 and 6-12 wherein the piston has a media opening defining a flow path in fluid communication with the first variable volume.

6. The circulation flow device of any one of claims 1 to 5 and 7 to 12, wherein the piston includes a media coupling structure surrounding the media opening.

7. The circulating flow apparatus of any one of claims 1-6 and 8-12 wherein the piston forms a fluid seal with the housing across the first variable volume.

8. The circulation flow device of any one of claims 1 to 7 and 9 to 12, wherein the first flow openings are flow inlets and flow outlets.

9. The circulation flow device of any one of claims 1 to 8 and 10 to 12, wherein the first flow opening is a flow inlet and the first flow opening is not a flow outlet.

10. The circulation flow device of any one of claims 1 to 9 and 11 to 12, the housing having a complementary variable volume, wherein the movable side wall defines the complementary variable volume.

11. The circulating flow apparatus of any one of claims 1 to 10 and 12 wherein the housing has a second flow opening extending to the complementary variable volume.

12. The circulation flow device of any one of claims 1 to 11, wherein the circulation flow device is a retrofit installation.

13. A circulation flow device comprising:

14. The circulation flow device of any one of claims 13 and 15 to 17, further comprising: an actuator coupled to the piston.

15. The circulating flow apparatus of any one of claims 13-14 and 16-17 wherein the actuator is configured to cyclically translate the piston between a first position and a second position in the cavity.

16. A circulation flow device as claimed in any one of claims 13 to 15 and 17, wherein the first position is towards a first end of the chamber and the second position is towards a second end of the chamber.

17. A circulation flow device as claimed in any one of claims 13 to 16, wherein the piston defines a media coupling around the media opening.

18. A circulation flow device comprising:

19. A circulation flow device comprising:

a flow control valve operatively coupled to the bladder outlet; and

20. A circulation flow device comprising:

an actuator operably coupled to the movable sidewall;

A flow sensor configured to sense a liquid flow rate; and