Cyclic Flow Device

Abstract

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

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 143,174, filed January 29, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to flow devices. More particularly, the present disclosure relates to periodic flow devices. [Background technology]

[0003] In the development of filtration media, a fluid flow test stand is often employed to help test the efficacy of the filtration media. The test stand generally defines a closed liquid flow circuit through which a fluid is pumped. The filtration media is typically mounted within the liquid flow circuit of the test stand such that the pumped fluid passes through the filtration media. The fluid is often spiked with one or more contaminants upstream of the filtration media, and the effectiveness of the filtration media in separating the contaminants can be quantified based on various parameters including efficiency, pressure drop, collection capacity, etc.

[0004] Typically, the fluid in a test stand is pumped through a liquid flow circuit at a constant flow rate. However, in many real-world implementations of filtration media, the flow rate varies during use. Such flow rate variations affect the performance of the filter media. As such, there is a general interest in having the ability to test filter media under variable flow rate conditions. Test stands have been developed that cyclically vary the flow rate of the fluid stream within the test stand, but such test stands can be relatively large, complex, and costly. Summary of the Invention [Means for solving the problem]

[0005] The cyclic flow devices described herein are configured to be installed along a liquid flow circuit to achieve a varying flow rate through at least a portion of the liquid flow circuit. The cyclic flow device can be a component of the liquid flow circuit or can be a retrofit device configured to be installed on an existing liquid flow circuit. In the latter case, the existing liquid flow circuit can be designed to have a constant flow rate and the cyclic flow device can be a retrofit device that modifies the liquid flow circuit to have a varying flow rate rather than a constant flow rate.

[0006] In some embodiments, the current technology relates to a periodic flow device. A housing has a first variable volume and a first flow opening. The first flow opening extends into the first variable volume. The housing has a movable sidewall defining the first variable volume. A first conduit coupling structure is located around the first flow opening. A linear actuator is secured to the movable sidewall.

[0007] 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 structure 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 comprises a media coupling structure around 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 and the movable sidewall defines a complementary variable volume. Additionally or alternatively, the housing has a second flow opening extending into the complementary variable volume. Additionally or alternatively, the cyclic flow apparatus is a retrofit device.

[0008] Some examples of the current art relate to a cyclic flow device having a housing and a piston. The housing has a flow inlet, a flow outlet, and a cavity extending axially 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 axially along the cavity. The piston defines an axially extending media opening in fluid communication with the cavity.

[0009] In some such embodiments, the device includes an actuator translatably coupled to the piston. Additionally or alternatively, the actuator is configured to periodically translate the piston between a first position and a second position within 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 around the media opening.

[0010] Yet another example of the current technology relates to a periodic flow device. A housing has a first variable volume defining a first flow opening and a conduit coupling structure around the first flow opening. The conduit coupling structure is configured to removably couple to a liquid flow circuit. An actuator is in operative communication with the housing. The actuator is configured to circumferentially cause the housing to accumulate liquid in the liquid flow circuit in the first variable volume and to expel liquid from the first variable volume into the liquid flow circuit.

[0011] In some such embodiments, the device includes a flow sensor disposed at 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 includes a piston translatably disposed within the cylinder, the first variable volume being defined by the cylinder and the piston. Additionally or alternatively, a complementary variable volume is defined by the cylinder and the piston, the cylinder defining a second flow opening extending into 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 periodic flow device is a retrofit device.

[0012] In yet another exemplary embodiment, the current art relates to a cyclic flow device having a housing defining a first variable volume and a complementary variable volume. The housing has an outer casing having a fixed volume. A bladder is disposed within the casing. The bladder defines a first variable volume. A bladder inlet extends into the first variable volume and a bladder outlet extends from the first variable volume. Complementary variable volumes are defined between the bladder and the casing. The casing defines a casing inlet and a casing outlet. A 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 restrictive position and an open position.

[0013] In some such embodiments, the bladder inlet and the casing inlet are at opposite axial ends of the housing. Additionally or alternatively, a flow sensor is positioned adjacent the bladder outlet, and a controller is coupled to the actuator, the controller being in data communication with the flow sensor. Additionally or alternatively, the device has a first conduit coupling structure around the bladder outlet, a second conduit coupling structure around the casing outlet, a third conduit coupling structure around the bladder inlet, and a fourth conduit coupling structure around the casing inlet, each conduit coupling structure configured to be coupled to a liquid flow circuit. Additionally or alternatively, the actuator is configured to cause the bladder to periodically accumulate and release liquid. Additionally or alternatively, the cyclic flow device is a retrofit device.

[0014] Some embodiments of the current technology relate to a periodic flow device having a housing defining a first variable volume and a first flow opening extending into the first variable volume. The housing has a movable sidewall defining the first variable volume. An actuator is operatively coupled to the movable sidewall. A flow sensor is configured to sense a flow rate of the liquid. 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 flow rate of the liquid relative to the flow sensor.

[0015] In some such embodiments, the movable sidewall includes a piston. Additionally or alternatively, the piston defines an opening and a media coupling structure around the opening. Additionally or alternatively, the flow sensor is disposed on the piston. Additionally or alternatively, the flow sensor is disposed adjacent to the first flow opening. Additionally or alternatively, the actuator is a linear actuator. Additionally or alternatively, the actuator is configured to operate a flow control valve. Additionally or alternatively, the housing has a first conduit coupling structure around the first flow opening, the first conduit coupling structure 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 and the movable sidewall defines the complementary variable volume. Additionally or alternatively, the housing has a second flow opening extending into the complementary variable volume.

[0016] The above summary is not intended to describe each or every embodiment, but rather, a more complete understanding of the illustrative embodiments will become apparent and appreciated by reference to the following detailed description of exemplary embodiments and claims, when taken in conjunction with the accompanying drawing figures. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic flow diagram of an exemplary testbed consistent with an exemplary embodiment of the current art; [Diagram 2] 1 is a schematic flow diagram of another exemplary testbed consistent with another exemplary embodiment of the present technology. [Diagram 3] 1 is a schematic cross-sectional view of an exemplary cyclic flow device. [Figure 4] 1 is a schematic cross-sectional view of another exemplary cyclical flow device. [Diagram 5] 1 is a schematic cross-sectional view of yet another exemplary cyclical flow device. [Figure 6]1 is a schematic cross-sectional view of yet another exemplary cyclical flow device. [Figure 7] 1 is a schematic cross-sectional view of an alternative exemplary variable volume housing. [Figure 8] 1 is a schematic cross-sectional view of yet another exemplary cyclical flow device. [Figure 9] 1 is a schematic cross-sectional view of yet another exemplary cyclical flow device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present technology may be more fully understood and appreciated by considering the following detailed description of various embodiments in connection with the accompanying drawings, in which:

[0019] The figures are drawn primarily for clarity and, as a result, are not necessarily drawn to scale. Additionally, various structures / components, including but not limited to fasteners, electrical components (wiring, cables, etc.), etc., may be shown diagrammatically or omitted from some or all of the figures in order to better explain aspects of the depicted embodiment or when the inclusion of such structures / components is not necessary for an understanding of the various exemplary embodiments described herein. However, the absence of showing / depicting such structures / components in a particular figure should not be construed as limiting the scope of the various embodiments in any way.

[0020] A cyclic flow device consistent with the technology disclosed herein can have a variety of different configurations. A cyclic flow device is generally configured to vary the flow rate of a liquid through a filter media holder. In various embodiments, the cyclic flow device is configured to vary the flow rate of a liquid through a portion of a liquid flow circuit. The cyclic flow device may be configured to periodically vary the flow rate of a liquid in a liquid flow circuit through a filter media holder. Such periodicity in the flow rate through the filter media holder can advantageously provide a media testing environment that is more representative of the actual operating environment of the filter media. "Cyclic flow" is generally defined as a flow rate that varies in a repeating pattern over time.

[0021] The cyclic flow device can be a retrofit device configured to sealably couple to an existing liquid flow circuit or an integral component of the liquid flow circuit. When the cyclic flow device is a retrofit device, it 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 cyclic flow device can be a retrofit device that modifies the liquid flow circuit to have a varying flow rate rather than a constant flow rate. As defined herein, a "retrofit device" is an accessory component configured to be added to an existing system to modify the system. In various embodiments, the cyclic flow device is a retrofit device configured to modify a constant flow rate liquid flow circuit to exhibit a cyclic flow condition through a portion of the liquid flow circuit.

[0022] FIG. 1 is a schematic flow diagram of a first exemplary liquid flow circuit 10 consistent with various implementations of the current art. The liquid flow circuit 10, in various embodiments, corresponds to a multi-pass filter media test stand. The liquid flow circuit 10 generally includes an inlet line 12 extending from a fluid reservoir 20 to a filter media holder 30. The fluid reservoir 20 is generally configured to contain a liquid that passes through the liquid flow circuit 10. The liquid may be, by way of example, water, hydraulic fluid, fuel, and oil. A contaminant injector 22 is generally in fluid communication with the liquid 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 in continuous amounts. The contaminant may be, for example, a test dust.

[0023] Various components may be disposed along the inlet line 12 of the liquid flow circuit 10. For example, a pump 40 may be fluidly coupled to the inlet line 12. The pump 40 may be configured to urge liquid flow around the liquid flow circuit 10. In various embodiments, the pump 40 is configured to urge liquid flow around the liquid flow circuit 10 at a particular liquid flow rate. In various embodiments, the particular liquid flow rate is selectable by a user, such as via a user interface in operative communication with the pump 40.

[0024] The filter media holder 30 is generally disposed across the inlet line 12. The filter media holder 30 defines an opening that is a filtering path for liquid in the liquid flow circuit 10. The filter media holder 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 liquid reservoir 20, the outlet line 14 being configured to accommodate the flow of liquid from the filter media holder 30 to the liquid reservoir 20 as the liquid is then repeatedly circulated through the liquid flow circuit until the test is stopped. Various additional and alternative components may be disposed along the outlet line 14.

[0025] The pressure sensor 50 is generally configured to sense a differential pressure across the media holder 30. In particular, the pressure sensor 50 can have a first sensor 52 configured to measure the fluid pressure upstream of the media holder 30, and the pressure sensor 50 can have a second sensor 54 configured to measure the fluid pressure downstream of the media holder 30. According to some testing procedures, testing of the filter media is terminated when the pressure sensor 50 senses a threshold differential pressure across the media holder 30 (and thus across the filter media attached to the media holder 30).

[0026] Liquid flow circuit 10 includes an upstream particle counter 60 and a downstream particle counter 62. The upstream particle counter 60 is positioned along liquid flow circuit 10 upstream of media holder 30. The downstream particle counter 62 is positioned along liquid flow circuit 10 downstream of media holder 30. Particle counters 60, 62 may be consistent with particle counters known in the art.

[0027] Positioned generally along liquid flow circuit 10 is a flow sensor 70 configured to monitor the flow rate of liquid through liquid flow circuit 10. In some embodiments, flow sensor 70 is in communication with a user interface to report the flow rate to a user. In some embodiments, flow sensor 70 is in data communication with a controller that is in operative communication with pump 40 to ensure that a constant flow rate is achieved. In some such embodiments, flow sensor 70 can also be in data communication with a user interface to report the flow rate to a user.

[0028] 2 is a schematic flow diagram of another exemplary test stand consistent with another exemplary embodiment of the current art. The liquid flow circuit 11, in various embodiments, is consistent with a single pass filter media test stand. The liquid flow circuit 11 generally defines a single pass flow path 15 extending between a fluid reservoir 21 and a filter media holder 31. More specifically, the single pass flow path 15 extends from a recirculation flow path 13 having the fluid reservoir 21, through the filter media holder 31, to a 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.

[0029] The fluid reservoir 21 is generally configured to contain a liquid that passes through the single pass flow path 15. The liquid may be, by way of example, water, hydraulic fluid, fuel, and oil. In the present example, the liquid includes a contaminant, such as test dust, and the mixture of liquid and contaminant is recirculated through the recirculation flow path 13 by the recirculation pump 42 to prevent precipitation of the contaminant within the reservoir 21.

[0030] Various components may be disposed along the single-pass flow path 15. A sample pump 41 may be fluidly coupled to the single-pass flow path 15. The sample pump 41 may be configured to induce liquid flow through the single-pass flow path 15. In various embodiments, the sample pump 41 is configured to induce liquid flow through the single-pass flow path at a particular liquid flow rate. In various embodiments, the particular liquid flow rate is selectable by a user, such as via a user interface in operative communication with the sample pump 41.

[0031] The media holder 31 is generally positioned across the single pass flow path 15. The media holder 31 defines an opening through which liquid in the single pass flow path 15 may filter. The media holder 31 is generally configured to secure the media around the opening such that liquid in the single pass flow path 15 may pass through the media. The single pass flow path 15 extends from the media holder 31 to the drain tank 23, which holds the liquid filtered by the media (on the media holder 31).

[0032] The pressure sensor 51 is generally configured to sense a differential pressure across the media holder 31. The pressure sensor 51 can have a configuration similar to that depicted in Figure 1, with a hydraulic pressure sensor upstream of the media holder 31 and another hydraulic pressure sensor downstream of the media holder 31. The single-pass flow path 15 can also have an upstream particle counter 61 and a downstream particle counter 63 consistent with particle counters known in the art.

[0033] Generally, a flow sensor 71 configured to monitor the flow rate of liquid through the single-pass flow path 15 is positioned along the single-pass flow path 15. In some embodiments, the flow sensor 71 is in communication with a user interface to report the flow rate to a 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 achieved. The flow sensor 71 can also be in data communication with the user interface to report the flow rate to a user.

[0034] The cyclic flow devices described herein may generally be installed in liquid flow circuits, such as those depicted in Figures 1 and 2, to allow the liquid flow through the liquid flow circuit to have a varying flow rate rather than a constant flow rate.

[0035] 3 depicts one exemplary schematic cross-sectional view of an exemplary periodic flow device 100 consistent with various embodiments. The periodic flow device 100 has a housing 110 that defines a first variable volume 116. The housing 110 has a movable sidewall 124 that defines the first variable volume 116. The housing 110 has a first flow opening 112 that extends to the first variable volume 116.

[0036] The periodic flow device 100 is generally configured to vary the flow rate of the liquid through the media holder 130. The periodic flow device 100 may be configured to create a periodic liquid flow condition through the media holder 130. In various embodiments, the periodic flow device 100 is configured to periodically vary the flow rate of the liquid through the media holder 130.

[0037] 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. The first flow opening 112 and the second flow opening 114 are defined at axially opposite ends of the housing 110. The first flow opening 112 can be a flow inlet in various embodiments. The second flow opening 114 can be a flow outlet in various embodiments. In various embodiments, the first flow opening 112 is only a flow inlet and not a flow outlet.

[0038] The movable sidewall 124 is a piston 124 disposed across the cavity 111. The piston 124 forms a fluid seal with the inner surface of the housing 110. The piston 124 is axially translatable generally linearly along the cavity 111. The position of the piston 124 within the cavity 111 thus defines a volume of a first variable volume 116 and a volume of a complementary variable volume 118 on an opposite side of the piston 124. The first flow opening 112 extends to the first variable volume 116. The second flow opening 114 extends to the complementary variable volume 118.

[0039] The piston 124 has a media holder 130 configured to generally hold a filtration media for testing. The media holder 130 has a media coupling structure 131 configured to generally secure the filter media to the piston 124. The media coupling structure 131 is configured to form a seal around an edge of the filter media to direct fluid flow through the media. The media coupling structure 131 may be, for example, a clamp. The media holder 130 defines a media opening 132 that is an opening that extends axially 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 .

[0040] In some embodiments, the media opening 132 is a plurality of discrete openings through the movable sidewall 124 that collectively define the media opening 132. Such a configuration advantageously provides structural support to 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 and configured to provide support to the filter media. Other configurations may also be used.

[0041] The actuator 120 is generally operatively 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 translational movement of the piston 124 through the cavity 111. More specifically, the actuator 120 is configured to periodically translate the piston 124 between a first position and a second position within the cavity 111. The direction and velocity of the piston 124 through the cavity 111 can dictate the direction, velocity, or both direction and velocity of fluid flow through the media opening 132, and more specifically, through the filter media secured to the media holder 130 of the piston.

[0042] In various embodiments, the periodic flow device 100 is configured to couple to a liquid reservoir (not currently depicted). In various embodiments, the periodic flow device 100 is configured to couple to a liquid flow circuit 10 that may incorporate a liquid reservoir, only a portion of which is currently depicted. Element numbers associated with the multi-pass liquid flow circuit 10 described above with reference to FIG. 1 are used in the discussion of the periodic flow device herein, although it will be understood that the liquid flow circuit may coincide with the single-pass liquid flow circuit 11 described above with reference to FIG. 2. In some embodiments, the periodic flow device 100 is integral with the liquid flow circuit 10. However, in some other examples, the periodic flow device 100 is configured to couple to the liquid flow circuit 10. The periodic flow device 100 has a first conduit coupling structure 113 around the first flow passage opening 112. The first conduit coupling structure 113 is configured to sealably couple to a flow line, such as the inlet line 12 of the liquid flow circuit 10, 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 structure 113 is configured to removably couple to the inlet line 12 of the liquid flow circuit 10. The first conduit coupling structure 113 can use a variety of different fastening mechanisms and combinations of fastening mechanisms, as are commonly known in the art.

[0043] The periodic flow device 100 generally has a second conduit coupling structure 115 about the second flow opening 114. The second conduit coupling structure 115 is configured to sealably couple 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 structure 115 is configured to removably couple to the outlet line 14 of the liquid flow circuit 10. The second conduit coupling structure 115 can use a variety of different fastening mechanisms and combinations of fastening mechanisms, as is commonly known in the art.

[0044] In the present example, the periodic flow device 100 is generally configured to be installed within the liquid flow circuit 10. In some embodiments, the periodic flow device 100 is configured to replace the media holder 30 of the liquid flow circuit 10. As such, the media holder 30 of the liquid flow circuit 10 can be removed, and the first conduit coupling structure 113 is coupled to the inlet line 12 of the liquid flow circuit 10, and the second conduit coupling structure 115 is coupled to the outlet line 14 of the liquid flow circuit 10. In some other embodiments, the periodic flow device 100 is configured integrally with the liquid flow circuit. In some, but not all, such embodiments, the periodic flow device 100 can omit one or both of the first and second conduit coupling structures 113, 115 when the inlet line 12 and / or the outlet line 14 are integral with the housing 110.

[0045] As described above, the liquid flow circuit 10 coupled to the cyclic flow device 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 liquid passing through the media opening 132 (or through the filter media coupled to the piston 124 around the media opening) is constant and is equal to the volumetric flow rate divided by the flow area of ​​the media opening 132. When the movable sidewall 124 translates linearly through the cavity 111 toward the second flow opening 114, the velocity of liquid passing through the media opening 132 decreases with the linear velocity of the movable sidewall 124. When the movable sidewall 124 translates linearly through the cavity 111 toward the first flow opening 112, the velocity of liquid passing through the media opening 132 increases with the linear velocity of the movable sidewall 124. In this manner, the fluid velocity through the media holder 130 can be varied.

[0046] In some embodiments, the device 100 incorporates a liquid flow sensor configured to sense one or both of the fluid flow rate or the fluid flow rate through the media holder 130. In various other embodiments, the device 100 does not incorporate a liquid flow sensor, and the processing system 142 may be configured to calculate the flow rate and / or flow rate of the liquid through the media holder 130. Such calculations are generally based on the flow rate through the liquid flow circuit 10 and the linear velocity of the piston 124, as described above. The processing system 142 may derive the flow rate of the liquid flow circuit 10 from either data entered by a user through a user interface, or data obtained from the flow sensors 70, 71 of the liquid flow circuit 10 as described above with reference to FIGS. 1 and 2. In some such examples, the flow sensors 70, 71 are in data communication with the processing system 142, which is configured to receive flow rate data from the flow sensors 70, 71 of the flow circuits 10, 11 (FIGS. 1 and 2). 3 as being separate from the controller 140, in some embodiments the processing system 142 is a component of the controller 140. In some embodiments consistent with FIG. 3, the processing system 142 may be, for example, a computer in communication with the controller 140.

[0047] In some embodiments, the controller 140 can be in operative 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 condition can be specified to the system by a user via a user interface, such as a computer, dial, keypad, touch screen, etc. The liquid flow rate condition can be matched to a cyclic flow condition. The processing system 142 can be configured to determine a cyclic velocity of the piston to achieve the specified liquid flow rate condition and communicate an operating command to the controller 140 configured to send a control signal to the actuator 120. In various embodiments, the actuator 120 is configured to actuate the cyclic flow condition in response to receiving a control signal from the controller 140.

[0048] In some embodiments, removing the media holder 30, 31 in the liquid flow circuit 10 may also result in removing the pressure sensors 50, 51 (FIGS. 1 and 2). Thus, the cyclical flow device 100 may incorporate a first pressure sensor 136 disposed on an upstream side of the movable sidewall 124 of the device 100, and a second pressure sensor 138 disposed on a second side of the movable sidewall 124 such that a differential pressure can be calculated across the filter media holder 130. In some embodiments, the system may be configured to calculate a flow rate of liquid through the media holder 130 based on the differential pressure data.

[0049] There may be various modifications to the design depicted in FIG. 3 that are 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 multiple flow inlets 112 and multiple flow outlets 114 may extend into the housing 110 from multiple directions. Multiple inlets extending into and out of the housing may advantageously increase the rate at which the fluid flow rate may be varied, for example. Additionally, in some embodiments the flow inlets and flow outlets may extend axially out of the housing, rather than laterally as depicted.

[0050] 4 is a schematic cross-sectional view of another exemplary periodic flow device 200 consistent with the technology disclosed herein. The periodic flow device 200 includes a housing 210 that defines a first variable volume 216. The housing 210 includes a movable sidewall 224 that defines the first variable volume 216. The housing 210 includes a first flow opening 212 that extends to the first variable volume 216. A conduit coupling structure 213 is disposed about the first flow opening 212. The conduit coupling structure 213 is configured to sealably couple to the liquid flow circuit 10 and can have a similar configuration to the conduit coupling structures described above. In the present example, the conduit coupling structure 213 is configured to couple to the inlet line 12 of the liquid flow circuit 10. However, it will be understood that in some implementations, the conduit coupling structure 213 is configured to couple to the outlet line 14 of the liquid flow circuit 10 and operate consistent with the present description. In some other embodiments, the cyclic flow device 200 is configured to be integral with the liquid flow circuit 10. In some but not all such embodiments, the cyclic flow device 200 may omit the conduit coupling structure 213 when the liquid flow circuit 10 is integral with the housing 110.

[0051] The periodic flow device 200 is configured to vary the flow rate of the liquid through the media holder 30. The periodic flow device 200 is generally configured to modify the liquid flow through the inlet line 12 (or outlet line) of the liquid flow circuit 10 to adjust the flow rate of the liquid through the media holder 30 of the liquid flow circuit 10. The periodic flow device 200 may be configured to create a periodic flow condition through the media holder 30. In various embodiments, the periodic flow device 200 is configured to periodically vary the flow rate of the liquid through the media holder 30. In the present example, the media holder 30 is not defined by the periodic flow device 200. Rather, here, the media holder 30 is a component of the liquid flow circuit 10 (only a portion of which is currently depicted) to which the periodic flow device 200 is configured to couple.

[0052] In the present example, the cyclic flow device 200 can operate as an accumulator. The cyclic 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 cyclic flow device 200 is configured to periodically 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 holder 30, the liquid passes through the outlet line 14 of the liquid flow circuit 10.

[0053] While in the present example, the cyclic flow device 200 is not coupled to the outlet line 14 of the liquid flow circuit 10, in some other embodiments, the cyclic flow device 200 is configured to couple to the outlet line 14 of the liquid flow circuit 10. In such embodiments, the cyclic flow device 200 is configured to periodically accumulate liquid from the outlet line 14 of the liquid flow circuit 10 within the housing 210 and release liquid from the housing 210 to the outlet line 14 of the liquid flow circuit 10. In such implementations, as liquid is released from the housing 210, the flow rate through the media holder 30 generally decreases and as liquid accumulates in the housing 210, the flow rate through the media holder 30 increases.

[0054] The housing 210 has a first flow opening 212 and a cavity 211 extending from the first flow opening 212. The cavity 211 extends axially from the first flow opening 212 towards the opposite axial end 202 of the housing 210. In the current example, the first flow opening 212 is a flow inlet, meaning that liquid enters the housing through the first flow opening 212. In the current example, the first flow opening 212 is also a flow outlet, meaning that liquid exits the housing 210 through the first flow opening 212. The first flow opening 212 extends to a first variable volume 216.

[0055] The movable sidewall 224 is a piston 224 disposed across the cavity 211. The piston 224 forms a fluid seal with the inner surface of the housing 210. The piston 224 is axially linearly translatable along the cavity 211. The position of the piston 224 within the cavity 211 thus defines the volume of the first variable volume 216. A complementary variable volume 218 is defined opposite the piston 224, but unlike the previous embodiment, here the complementary variable volume 218 does not receive liquid from the liquid flow circuit 10. In further contrast to the previous embodiment, the piston 224 does not define a media holder. Rather, the media holder 30 is a component of the liquid flow circuit 10.

[0056] The actuator 220 is generally operatively coupled to the movable sidewall 224. In the present example, the actuator 220 is translatably coupled to the piston 224 via a shaft 222. In various embodiments, the actuator 220 is a linear actuator fixed to the piston 224. The actuator 220 is configured to actuate linear translation of the piston 224 through the cavity 211. More specifically, the actuator 220 is configured to periodically translate the piston 224 between a first position and a second position in the cavity 211. The direction and velocity of the piston 224 through the cavity 211 is related to the rate of fluid flow through the media holder 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.

[0057] More specifically, the cyclic flow device 200 is configured to fluidly couple to the liquid flow circuit 10 that circulates liquid at a constant volumetric flow rate. When the movable side wall 224 is stationary within the cavity 211, the velocity of liquid passing through the media holder 30 (or through the filter media coupled to the media holder around the media opening of the media holder) is constant and is equal to the volumetric flow rate divided by the flow area of ​​the opening of the media holder 30. When the movable side wall 224 is linearly translated 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. In this way, the volumetric flow rate towards the media holder 30 is reduced by the volumetric flow rate of liquid moving into the first variable volume 216 of the housing 210, reducing the velocity of the liquid passing through the media holder 30. As the movable sidewall 224 translates linearly through the cavity 211 towards the first flow opening 212, liquid is expelled from the first variable volume 216 into the liquid flow circuit 10. As a result, the volumetric flow rate through the media holder 30 increases by the volumetric flow rate of liquid exiting the housing 210. In this manner, the fluid velocity through the sample filter media secured across the media holder 30 can be varied.

[0058] In some embodiments, the periodic flow device 200 includes a flow sensor 234 configured to sense a flow rate of the liquid. For example, the flow sensor 234 can be coupled to the housing 210 adjacent the first flow opening 212 and sense a flow rate of the liquid through the first flow opening 212. In some other embodiments, the flow sensor 234 of the device 200 can be coupled to the media holder 30 in the liquid flow circuit 10. In embodiments incorporating a flow sensor 234, the flow sensor 234 can communicate with a user interface, for example, to record and report the flow rate of the liquid to a user. In various examples, the flow sensor 234 is in data communication with the controller 240. The controller 240 can be in operative communication with the actuator 220 such that the controller 240 is configured to manipulate the actuator (thereby translating the movable sidewall 224) to determine a flow rate of the liquid relative to the flow sensor, and more particularly through the media holder 30. In various embodiments, the periodic flow device 200 does not include a flow sensor 234. In some embodiments, the flow sensor can be a component of the liquid flow circuit 10, as described above. In some embodiments, the system is configured to calculate the flow rate through the media holder 30 based on the liquid flow rate (either determined by the flow sensor or input by a user) through the liquid flow circuit combined 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.

[0059] In the present exemplary configuration, the cyclic flow device 200 does not replace any components of the liquid flow circuit 10 (e.g., as in the example of FIG. 3 where it is configured to replace the media holder and possibly other components). Rather, in the present example, the cyclic flow device 200 is configured to be added to the liquid flow circuit 10.

[0060] 5 is a schematic cross-sectional view of yet another exemplary periodic flow device 300. The periodic flow device 300 is similar to that described above with reference to FIG. 4, except that in this example, a 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 a 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 periodic flow device 300 can be described as being in parallel with the media holder 30. Such a configuration advantageously facilitates modifying or cyclically varying the velocity of the fluid through the media holder 30 without significantly changing the volumetric flow through the liquid circuit upstream and downstream of the periodic flow device 300. For example, as the first variable volume 316 increases to decrease the volume of flow through the media holder 30, the complementary variable volume 318 decreases to expel a corresponding volume of liquid.

[0061] 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 periodic flow device 300 has the housing 310 defining a first variable volume 316. The housing 310 has a movable sidewall 324 defining the first variable volume 316 and a complementary variable volume 318. The housing 310 has the first flow opening 312 extending into the first variable volume 316 and the second flow opening 314 extending into the complementary variable volume 318. The first flow opening 312 and the second flow opening 314 are defined at axially opposite ends of the housing 310. In the present example, the first flow opening 312 and the second flow opening 314 each operate as a flow inlet and a flow outlet for the housing 310.

[0062] The periodic flow device 300 is generally configured to vary the flow rate of liquid through the media holder 30. The periodic flow device 300 may be configured to create a condition of periodic liquid flow through the media holder 30. In various embodiments, the periodic flow device 300 is configured to periodically vary the flow rate of liquid through the media coupling structure 30. Similar to the example discussed with respect to FIG. 4, in the present example, the media holder 30 is not a component of the periodic flow device 300. Rather, the media holder 30 is a component of the liquid flow circuit 10 to which the periodic flow device 300 is configured to couple.

[0063] The movable sidewall 324 is a piston 324 that is disposed across the cavity 311. The piston 324 forms a fluid seal with the inner surface of the housing 310. The piston 324 is generally linearly translatable axially along the cavity 311. The position of the piston 324 within the cavity 311 thus 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.

[0064] An actuator 320 is translatably coupled to the movable sidewall 324. In the present example, the actuator 320 is secured to the piston 324 via a shaft 322. In various embodiments, the actuator 320 is a linear actuator secured to the piston 324. The actuator 320 is configured to actuate linear translation of the piston 324 through the cavity 311. More specifically, the actuator 320 is configured to periodically translate the piston 324 between a first position and a second position within the cavity 311. The direction and velocity of the piston 324 through the cavity 311 can define a rate of fluid flow through the media holder 30, and more specifically, through the filter media secured to the media holder 30. The actuator 320 can be configured to periodically cause the housing to accumulate liquid from the inlet line 12 of the liquid flow circuit 10 in the first variable volume 316 and expel liquid from the first variable volume 316 to the inlet line 12 of the liquid flow circuit 10.

[0065] The periodic flow device 300 generally has a first conduit coupling structure 313 about the first flow opening 312 configured to sealably couple 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 structure 313 is configured to removably couple to the inlet line 12 of the liquid flow circuit 10. The periodic flow device 300 also has a second conduit coupling structure 315 about the second flow opening 314 configured to sealably couple to the outlet line 14 of the liquid flow circuit 10 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 structure 315 is configured to removably couple to the outlet line 14 of the liquid flow circuit 10. In some other embodiments, the periodic flow device 300 is configured to be integral with the liquid flow circuit 10. In some, but not all, such embodiments, the cyclic flow device 300 may omit one or both of the first and second conduit coupling structures 313, 315 when the inlet line 12 and / or the outlet line 14 are integral with the housing 110.

[0066] As discussed thus far, the liquid flow circuit 10 coupled to the cyclic flow device 300 is generally configured to circulate liquid through the flow circuit at a constant volumetric flow rate. When the movable side wall 324 is stationary within the cavity 311, the velocity of liquid passing through the opening of the media holder 30 (or through the filter media coupled to the media holder) is constant and is equal to the volumetric flow rate divided by the flow area of ​​the opening of the media holder 30. As the movable side wall 324 is linearly translated 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 is reduced by the volumetric flow rate of liquid into the first variable volume 316 of the housing 310, reducing the velocity of liquid passing through the media holder 30. At the same time, the liquid in the complementary variable volume 318 is discharged into the outlet line 14 of the liquid flow circuit 10.

[0067] As the movable side wall 324 is linearly translated through the cavity 311 toward the first flow opening 312, liquid from the first variable volume 316 of the housing 310 is discharged into the inlet line 12 of the liquid flow circuit 10. The volumetric flow rate through the inlet line 12 increases by the volumetric flow rate of liquid exiting the first variable volume 316 of the housing 310, increasing the velocity of liquid passing through the media holder 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 decreases by the volumetric flow rate of liquid entering the complementary variable volume 318 of the housing 310.

[0068] In the manner described above, the fluid velocity through the sample filter media fixed across the media holder 30 can be varied periodically.

[0069] As discussed above, the cyclic flow device 300 can have a flow sensor 334 configured to sense a flow rate of the liquid. The flow sensor 334 can be configured to sense a flow rate of the liquid through the first flow opening 312 or elsewhere, as discussed above. The flow sensor 334 can be in communication with a user interface, a controller 340, or both a user interface and a controller 340. The controller 340 can be in operative communication with the actuator 320, as discussed above.

[0070] 6 is a schematic cross-sectional view of yet another exemplary cyclical flow device. Similar to the example described above with reference to FIG. 5, here a 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 holder 30, and a 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 holder 30. However, in the present example, the first variable volume 416 of the housing 410 is configured to be placed 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, the complementary variable volume 418 of the housing 410 feeds into the outlet line 14 of the liquid flow circuit 10. This configuration may advantageously facilitate modifying or cyclically varying the velocity of the fluid through the media holder 30 without changing the volumetric flow through the liquid circuit upstream and downstream of the cyclical flow device 400.

[0071] 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 periodic flow device 400 defines a first variable volume 416 and a complementary variable volume 418. The housing 410 has a movable sidewall 424 that defines the first variable volume 416 and the complementary variable volume 418. The housing 410 has the first flow opening 412 that extends to the first variable volume 416 and the second flow opening 414 that extends to the complementary variable volume 418. The first flow opening 412 and the second flow opening 414 are defined at axially opposite ends of the housing 410. In this 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 acts as a flow inlet and a flow outlet to the housing 410 .

[0072] The first conduit coupling structure 413 is disposed about the first flow opening 412 configured to sealably couple 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 structure 413 is configured to removably couple to the inlet line 12 of the liquid flow circuit 10. The second conduit coupling structure 415 is disposed about the second flow opening 414 configured to sealably couple to the outlet line 14 of the liquid flow circuit 10 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 structure 415 is configured to removably couple to the outlet line 14 of the liquid flow circuit 10.

[0073] As with some previous examples, here the movable sidewall 424 is a piston 424 disposed across a cavity 411 that defines a first variable volume 416 and a complementary variable volume 418 of the housing 410. The piston 424 forms a fluid seal with an inner surface of the housing 410. The piston 424 is generally linearly translatable axially along the cavity 411. The position of the piston 424 within the cavity 411 thus 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.

[0074] The actuator 420 is translatably coupled to the piston 424 via a shaft 422. In various embodiments, the actuator 420 is a linear actuator secured to the piston 424. The actuator 420 is configured to actuate linear translation of the piston 424 through the cavity 411. More specifically, the actuator 420 is configured to periodically translate the piston 424 between a first position and a second position within the cavity 411. The direction and velocity of the piston 424 through the cavity 411 can define a rate of fluid flow through the media holder 30, and more specifically through the filter media secured to the media holder 30. The actuator 420 can be configured to periodically cause the housing 410 to accumulate liquid from the inlet line 12 of the liquid flow circuit 10 in the first variable volume 416 and expel liquid from the first variable volume 416 to the inlet line 12 of the liquid flow circuit 10.

[0075] Unlike the previous examples, in the current example, the housing 410 has a third flow opening 419 configured to be fluidly coupled to the inlet line 12 of the liquid flow circuit 10. The third flow opening 419 is configured to be positioned upstream of the first flow opening 412 along the inlet line 12 of the liquid flow circuit 10. A third conduit coupling structure 417 around 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 structure 417 can be consistent with other conduit coupling structures described herein. As with the above examples, it should be noted that in some embodiments where the periodic flow device is integral to the fluid flow circuit 10, one or more of the conduit coupling structures 413, 415, 417 may be omitted.

[0076] The first variable volume 416 is configured to fluidly couple the inlet line 12 and the media holder 30. The first flow opening 412 and the third flow opening 419 are in direct fluid communication with the first variable volume 416. In particular, in the present example, the piston 424 and the shaft 422 define a liquid conduit 426 that fluidly couples the third flow opening 419 and the first variable volume 416. In this example, the liquid conduit 426 passes through but is fluidly isolated from the complementary variable volume 418. In operation, the liquid flow circuit 10 can be configured to direct liquid flow through the liquid conduit 426 at a constant volumetric flow rate.

[0077] As with the previous embodiments described, the periodic flow device 400 is configured to vary the flow rate of liquid through the media holder 30. The periodic flow device 400 can be configured to create a condition of periodic liquid flow through the media holder 30. In various embodiments, the periodic flow device 400 is configured to periodically vary the flow rate of liquid through the media binding structure 30.

[0078] As described above, when the movable sidewall 424 is stationary within the cavity 411, the velocity of liquid passing through the media holder 30 (or through the filter media coupled to the media holder 30) is constant and is 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 is linearly translated through the cavity 411 away from the first flow opening 412, the volumetric flow rate decreases by the volumetric flow rate of liquid into the first variable volume 416, decreasing the velocity of liquid passing through the media holder 30. As the movable sidewall 424 is linearly translated through the cavity 411 towards the first flow opening 412, the volumetric flow rate through the first flow opening 412 increases by the volumetric flow rate of liquid pushed out of the first variable volume 416 by the piston, increasing the velocity of liquid passing through the media holder 30.

[0079] In various embodiments, a flexible hose may fluidly couple the liquid conduit 426 of the shaft 422 to the inlet line 12 to accommodate linear translation of the piston 424 (and thus the shaft 422).

[0080] As mentioned above, the periodic flow device 400 can have a flow sensor 434 configured to sense a flow rate of the liquid. The flow sensor 434 can be configured to sense a flow rate of the liquid through the first flow opening 412 or elsewhere, as has been described above. The flow sensor 434 can be in communication with a user interface, a controller 440, or both a user interface and a controller 440. The controller 440 can be in operative communication with the actuator 420, as described above.

[0081] In the present example, the device 400 has a first variable volume 416 coupled to the inlet line 12 immediately upstream of the media holder 30, although 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 holder 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 holder 30. In such an example, the first variable volume 416 of the housing 410 may be configured to be placed 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 feed into the inlet line 12 of the liquid flow circuit 10.

[0082] It should be noted that in the embodiment depicted and described above, the displacement of a volume of a first liquid from a first variable volume by the piston results in an opposite displacement of a corresponding volume of liquid from a complementary variable volume, where the corresponding volume is smaller than the volume of the first liquid. This is because the shaft reduces the volume of the complementary variable volume relative 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, where 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 can be substituted for other housings disclosed herein and can be configured to define openings and flow paths consistent with previously disclosed embodiments.

[0083] 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 within the fluid flow passage 511. A first variable volume 516 and a complementary variable volume 518 are defined within the housing 510 on opposite sides of the movable sidewall 524. The movable sidewall 524 is a piston 524. A first shaft 522 is configured to couple the piston 524 to an actuator (not depicted here). The first shaft 522 extends axially 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 on the opposite side of 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. The cross-sectional areas of the first shaft 522 and the second shaft 526 are equal in various embodiments, where the cross-sectional areas are perpendicular to the axial extension of the housing 510 .

[0084] 8 is a schematic cross-sectional view of yet another exemplary periodic flow device 600 consistent with various embodiments. The periodic flow device 600 is configured to be coupled to a liquid flow circuit 10. The periodic flow device 600 has a housing 610 defining a first flow opening 612 and a first conduit coupling structure 613 around the first flow opening 612. The first conduit coupling structure 613 is configured to be removably coupled to the liquid flow circuit 10. An actuator 620 is in operative communication with the housing 610. The actuator 620 is configured to periodically accumulate liquid within the liquid flow circuit 10 in the housing 610 (particularly, the first variable volume 616) and release liquid from the housing 610 (particularly, 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, flow sensor 634 is positioned adjacent bladder outlet 612 (the bladder is described in more detail below). Flow sensor 634 may be configured to sense the flow rate of liquid through first flow opening 612 or elsewhere, as described above. Flow sensor 634 may be in communication with a user interface, a controller 640, or both a user interface and a controller 640. Controller 640 may be in operative communication with actuator 620 and in data communication with flow sensor 634 to alter the flow rate of liquid through first flow opening 612.

[0085] 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 in-line with the inlet line 12 of the liquid flow circuit 10. The first variable volume 616 resides in series between the inlet line 12 and the media holder 30. As such, the first variable volume 616 has a first conduit coupling structure 613 configured to couple to the liquid flow circuit 10 upstream of the media holder 30 and a second conduit coupling structure 617 around the second flow opening 619 configured to couple to the liquid flow circuit 10 upstream of the first conduit coupling structure 613.

[0086] The complementary variable volume 618 is configured to be coupled in-line with the outlet line 14 of the liquid flow circuit 10. The complementary variable volume 618 is in series between the media holder 30 and the outlet line 14. Thus, the housing 610 has a third conduit coupling structure 615 around a third flow opening 614 in communication with the complementary variable volume 618. The third conduit coupling structure 615 is configured to couple to the liquid flow circuit 10 downstream of the media holder 30. The housing 610 has a fourth conduit coupling structure 621 around a fourth flow opening 623 in communication with the complementary variable volume 618. The fourth conduit coupling structure 621 is configured to couple to the liquid flow circuit 10 upstream of the third conduit coupling structure 615. Similar to the above examples, in some embodiments where the cyclic flow device is integral to the fluid flow circuit 10, one or more of the conduit coupling structures 613, 615, 617, 621 may be omitted.

[0087] Similar to other embodiments described herein, the housing 610 has a movable sidewall 624 that defines a first variable volume 616. However, unlike previous examples, in the current example, the movable sidewall 624 is a bladder 624. The bladder 624 is generally constructed of a hollow flexible material, such as an elastomeric material, such as rubber. In some other embodiments, the movable sidewall can be a bellows having a collapsible, inflatable sidewall. The first flow opening 612 of the bladder 624 can be referred to as a bladder outlet 612. The second flow opening 619 of the bladder 624 can 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.

[0088] In the current example, the housing 610 has an outer casing 644 that houses a bladder 624. The outer casing 644 is generally rigid to define a fixed volume. A complementary variable volume 618 is defined by a volume between the bladder 624 and an inner surface of the outer casing 644. Such a configuration may advantageously allow liquid accumulated by the first variable volume 616 to displace liquid accumulated by the complementary variable volume 618. A third flow opening 614 and a fourth flow opening 623 are defined by the outer casing 644. The third flow opening 614 may be referred to as a casing outlet 614, and the fourth flow opening 623 may be referred to as a casing inlet 623. In the current configuration, the casing inlet 623 and the bladder inlet 619 are at opposite axial ends of the housing 610. Similarly, the casing outlet 614 and the bladder outlet 612 are at opposite axial ends of the housing 610.

[0089] In the present example, the actuator 620 is operably coupled to the movable sidewall 624. In particular, a flow control valve 636 is coupled to the bladder 624 across the bladder outlet 612, and the actuator 620 is operably coupled to the flow control valve 636. The actuator 620 is configured to selectively swing the valve 636 between a restrictive position and an open position to decrease and increase the flow rate of liquid through the first flow outlet 612, and thus decrease and increase the flow rate of liquid through the media holder 30. Decreasing the flow rate of liquid through the first flow opening 612 causes the bladder 624 to retain liquid from the inlet line 12 of the liquid flow circuit 10, and the bladder 624 expands to accommodate the increased volume of liquid within the bladder. Increasing the flow rate of liquid through the first flow opening 612 causes the bladder 624 to release liquid into the liquid flow circuit 10 and contracts to accommodate the decreased volume of liquid within the bladder 624.

[0090] 9 is a schematic cross-sectional view of yet another exemplary cyclical flow device. Similar to the example described above with reference to FIG. 8, here a first variable volume 716 of a housing 710 is configured to be in-line with an inlet line 12 of a liquid flow circuit 10, and a complementary variable volume 718 of the housing 710 is configured to be in fluid communication with an outlet line 14 of the liquid flow circuit 10. Configuring both the first variable volume 716 and the complementary variable volume 718 to be in-line with a flow line of the liquid flow circuit may advantageously allow for a constant fluid flow through the volumes and reduce accumulation or settling of particles within the volumes. In the current example, the first variable volume 716 of the housing 710 is configured to be placed in-line with an inlet line 12 of a liquid flow circuit 10, and the complementary variable volume 718 of the housing 710 is in fluid communication with an outlet line 14 of the liquid flow circuit 10. This configuration advantageously facilitates modifying or cyclically varying the velocity of fluid through the media holder 30 without changing the volumetric flow through the liquid flow circuit 10 upstream and downstream of the cyclic flow device 700.

[0091] 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 periodic flow device 700 defines a first variable volume 716 and a complementary variable volume 718. The housing 710 has a movable sidewall 724 that defines the first variable volume 716 and the complementary variable volume 718. The housing 710 has the first flow opening 712 that extends to the first variable volume 716 and the second flow opening 714 that extends to the complementary variable volume 718. The first flow opening 712 and the second flow opening 714 are defined at opposite axial ends of the housing 710. In the current example, the first flow opening 712 acts as a flow outlet to the first variable volume 716 of the housing 710. The first flow opening 712 is not a flow inlet. The second flow opening 714 acts as a flow outlet to a complementary variable volume 718 of the housing 710.

[0092] The first conduit coupling structure 713 is configured to sealably couple to the liquid flow circuit 10 and is disposed about the first flow opening 712 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 structure 713 is configured to removably couple to the inlet line 12 of the liquid flow circuit 10. The second conduit coupling structure 715 is configured to sealably couple to the outlet line 14 of the liquid flow circuit and is disposed about the second flow opening 714 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 structure 715 is configured to removably couple to the outlet line 14 of the liquid flow circuit 10.

[0093] The housing 710 has a third flow opening 719 configured to be in fluid communication with 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 upstream of the first flow opening 712 along the inlet line 12 of the liquid flow circuit 10. The third flow opening 719 acts as an inlet to the first variable volume 716. A third conduit coupling structure 717 around 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 structure 717 may be consistent with other conduit coupling structures described herein.

[0094] 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 upstream of the second flow opening 714 along the outlet line 14 of the liquid flow circuit 10. The second flow opening 714 and the fourth opening 723 are in direct fluid communication with a complementary variable volume 718. The fourth flow opening 723 acts as an inlet to the complementary variable volume 718. A fourth conduit coupling structure 721 around the fourth flow opening 723 is configured to sealably couple to the outlet line 14 of the liquid flow circuit 10. The fourth conduit coupling structure 721 may be consistent with other conduit coupling structures described herein. As with the examples above, in some embodiments where the periodic flow device is integral to the fluid flow circuit 10, one or more of the conduit coupling structures 713, 715, 717, 721 may be omitted.

[0095] As with some previous examples, here the movable sidewall 724 is a piston 724 disposed across a fluid passageway 711 that defines a first variable volume 716 and a complementary variable volume 718 of the housing 710. The piston 724 forms a fluid seal with an inner surface of the housing 710. The piston 724 is generally linearly translatable axially 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.

[0096] An actuator 720 is translatably coupled to the piston 724 via a shaft 722. In various embodiments, the actuator 720 is a linear actuator secured to the piston 724. The actuator 720 is configured to actuate linear translation of the piston 724 through the cavity 711. More specifically, the actuator 720 is configured to periodically translate the piston 724 between a first position and a second position within the cavity 711. The direction and velocity of the piston 724 through the cavity 711 can define a velocity of fluid flow through the media holder 30, and more specifically through the filter media secured to the media holder 30.

[0097] As with the previous embodiments described, the periodic flow device 700 is configured to vary the flow rate of liquid through the media holder 30. The periodic flow device 700 can be configured to create a condition of periodic liquid flow through the media holder 30. In various embodiments, the periodic flow device 700 is configured to periodically vary the flow rate of liquid through the media coupling structure of the media holder 30.

[0098] In various embodiments, the liquid flow circuit 10 coupled to the cyclical flow device 700 is configured to circulate liquid through the liquid flow circuit at a constant volumetric flow rate. Thus, when the movable sidewall 724 is stationary within the cavity 711, the velocity of liquid passing through the media holder 30 (or through the filter media coupled to the media holder 30) is constant and is equal to the volumetric flow rate divided by the flow area of ​​the opening in the media holder 30. As the movable sidewall 724 is linearly translated through the cavity 711 away from the first flow opening 712, the volumetric flow rate through the first flow opening 712 decreases by the volumetric flow rate of liquid into the first variable volume 716, which decreases the velocity of the liquid passing through the media holder 30. As the movable side wall 724 is linearly translated through the cavity 711 towards the first flow opening 712, the volumetric flow rate through the first flow opening 712 increases due to the volumetric flow rate of liquid pushed out of the first variable volume 716 by the piston, which increases the velocity of the liquid passing through the media holder 30.

[0099] As mentioned above, the cyclic flow device 700 can include a flow sensor 734 configured to sense a flow rate of the liquid. The flow sensor 734 can be configured to sense a flow rate of the liquid through the first flow opening 712 or elsewhere, as has been described above. The flow sensor 734 can be in communication with a user interface, a controller 740, or both a user interface and a controller 740. The controller 740 can be in operative communication with the actuator 720, as described above.

[0100] In various embodiments of the presently disclosed technology, the system is configured to vary the first variable volume between its minimum possible volume and another volume. Such a system configuration reduces the chance that contaminants suspended in the liquid remain in the first variable volume, thus ensuring that the 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 those depicted in Figures 3, 5, 6, 8 and 9), various implementations of the system disclosed herein are configured to vary the complementary variable volume between its minimum possible volume and another volume for the same reasons. Since the minimum possible volume of the complementary variable volume results in the maximum possible volume of the first variable volume, and the minimum possible volume of the first variable volume results in the maximum possible volume of the complementary variable volume, such a system is configured to vary the first variable volume (and the complementary variable volume) between its minimum and maximum possible volumes.

[0101] For example, in an embodiment in which the first variable volume and the complementary variable volume are defined by a cylinder and a piston translatably disposed within the cylinder (such as those depicted in FIGS. 3, 5, 6, 7, and 9), the system is configured to oscillate the piston between the axial ends of the cylinder such that the minimum volume of the first variable volume approaches zero and the maximum volume of the first variable volume approaches the volume of the cylinder minus the volume of the piston as the complementary variable volume approaches zero. As another example, in an embodiment in which the first variable volume is defined by a bladder and the complementary variable volume is defined by a casing (such as those depicted in FIG. 8), the minimum possible volume of the first variable volume 616 may approach zero relative to the maximum possible volume of the complementary variable volume 618, the volume of the casing minus the volume of the bladder 624, as the internal volume of the bladder 624 approaches zero. The minimum possible volume of complementary variable volume 618 may approach zero in response to bladder 624 expanding to its maximum possible volume, such that bladder 624 expands to substantially fill outer casing 644 .

[0102] In some embodiments of the current technology, it may be desirable to use different periodic devices having alternative configurations in combination with a particular liquid flow circuit. For example, some test conditions may benefit from a periodic flow device having a relatively large first variable volume, while other test conditions may benefit from a periodic flow device having a relatively small first variable volume. Thus, some systems consistent with the technology disclosed herein incorporate multiple periodic devices, each coupled in parallel to a liquid flow circuit. Each periodic device may define a different sized first variable volume (and complementary variable volumes, if relevant). Each periodic device may be consistent with those discussed herein. In such embodiments, the system may incorporate a switch, such as an electronic or mechanical switch, via which each periodic device may be selected for operable engagement with the liquid flow circuit. In some such embodiments, the liquid communication between each periodic device and the liquid flow circuit is mutually exclusive.

[0103] Description of the embodiments Embodiment 1. a housing having a first variable volume and a first flow opening extending into the first variable volume, the housing comprising a movable sidewall defining the first variable volume and a first conduit coupling structure about the first flow opening; A linear actuator fixed to the movable side wall; A cyclic flow device comprising:

[0104] Embodiment 2. 13. The cyclic flow device of any one of claims 1 and 3-12, wherein the movable side wall is a piston.

[0105] Embodiment 3. 13. The cyclic flow device of any one of claims 1-2 and 4-12, wherein the linear actuator and the moveable side wall are configured to vary a flow rate of liquid within the liquid flow circuit.

[0106] Embodiment 4. 13. The cyclic flow device of any one of claims 1 to 3 and 5 to 12, wherein the first conduit coupling structure is configured to sealably couple to a liquid flow circuit.

[0107] Embodiment 5. 13. The cyclic flow device of any one of claims 1-4 and 6-12, wherein the piston has a media opening defining a flow passage in fluid communication with the first variable volume.

[0108] Embodiment 6. 13. The cyclic flow device according to any one of claims 1 to 5 and 7 to 12, wherein the piston comprises a media coupling structure around the media opening.

[0109] Embodiment 7. 13. The cyclic flow device of any one of claims 1 to 6 and 8 to 12, wherein the piston forms a fluid seal with the housing across the first variable volume.

[0110] Embodiment 8. 13. The cyclic flow device according to any one of claims 1 to 7 and 9 to 12, wherein the first flow openings are a flow inlet and a flow outlet.

[0111] EMBODIMENT 9. 13. The cyclic flow device according to 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.

[0112] Embodiment 10. 13. The cyclic flow device of any one of claims 1-9 and 11-12, wherein the housing has a complementary variable volume and the movable sidewall defines a complementary variable volume.

[0113] Embodiment 11. 13. The cyclic flow device of any one of claims 1 to 10 and 12, wherein the housing has a second flow opening extending into a complementary variable volume.

[0114] Embodiment 12. 12. The cyclic flow device of claim 1, wherein the cyclic flow device is a retrofit device.

[0115] Embodiment 13. a housing having a flow inlet, a flow outlet, and a cavity extending axially from the flow inlet to the flow outlet; a piston disposed across the cavity and forming a seal with the housing, the piston being linearly translatable axially along the cavity and defining an axially extending media opening in fluid communication with the cavity; A cyclic flow device comprising:

[0116] Embodiment 14. 19. The cyclic flow device of any one of claims 13 and 15-18, further comprising an actuator coupled to the piston.

[0117] EMBODIMENT 15. 19. The cyclic 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 within the cavity.

[0118] EMBODIMENT 16. 19. The cyclic flow device of any one of claims 13-15 and 17-18, wherein the first position is towards a first end of the cavity and the second position is towards a second end of the cavity.

[0119] EMBODIMENT 17. 19. The cyclic flow device of any one of claims 13 to 16 and 18, wherein the piston defines a media binding structure around the media opening.

[0120] EMBODIMENT 18. 18. The cyclic flow device of any one of claims 13 to 17, wherein the cyclic flow device is a retrofit device.

[0121] EMBODIMENT 19. a housing having a first variable volume defining a first flow opening and a conduit coupling structure surrounding the first flow opening, the conduit coupling structure configured to be removably coupled to a liquid flow circuit; an actuator in operative communication with the housing, the actuator being configured to cause the housing to periodically accumulate liquid in the liquid flow circuit in the first variable volume and release liquid from the first variable volume into the liquid flow circuit; A cyclic flow device comprising:

[0122] EMBODIMENT 20. 28. The periodic flow device of any one of claims 19 and 21-27, further comprising a flow sensor positioned within the first flow opening and a controller coupled to the actuator, the controller in data communication with the flow sensor.

[0123] EMBODIMENT 21. 28. The cyclic flow device of any one of claims 19-20 and 22-27, wherein the housing is a cylinder.

[0124] EMBODIMENT 22. 28. The cyclic flow device of any one of claims 19-21 and 23-27, further comprising a piston translatably disposed within the cylinder, the first variable volume being defined by the cylinder and the piston.

[0125] EMBODIMENT 23. 28. The cyclic flow device of any one of claims 19-22 and 24-27, further comprising a complementary variable volume defined by a cylinder and a piston, the cylinder defining a second flow opening extending into the complementary variable volume.

[0126] EMBODIMENT 24. 28. The cyclic flow device of any one of claims 19 to 23 and 25 to 27, wherein the first variable volume is a bladder.

[0127] EMBODIMENT 25. 28. The cyclic 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.

[0128] 26. 28. The cyclic 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.

[0129] EMBODIMENT 27. 27. The cyclic flow device of any one of claims 19 to 26, wherein the cyclic flow device is a retrofit device.

[0130] 28. a housing defining a first variable volume and a complementary variable volume, the housing comprising an outer casing having a fixed volume and a bladder disposed within the casing, the bladder defining the first variable volume, a bladder inlet extending into the first variable volume, and a bladder outlet extending from the first variable volume, complementary variable volumes being defined between the bladder and the casing, the casing defining a casing inlet and a casing outlet; a flow control valve operably coupled to the bladder outlet; an actuator operably coupled to the flow control valve, the actuator configured to oscillate the flow control valve between a restricted position and an open position; A cyclic flow device comprising:

[0131] 29. 34. The cyclic flow device of any one of claims 28 and 30-33, wherein the bladder inlet and the casing inlet are at opposite axial ends of the housing.

[0132] EMBODIMENT 30. 34. The cyclical flow device of any one of claims 28-29 and 31-33, further comprising a flow sensor positioned adjacent to the bladder outlet and a controller coupled to the actuator, the controller in data communication with the flow sensor.

[0133] EMBODIMENT 31. 34. The cyclical flow device of any one of claims 28-30 and 32-33, further comprising a first conduit coupling structure around the bladder outlet, a second conduit coupling structure around the casing outlet, a third conduit coupling structure around the bladder inlet, and a fourth conduit coupling structure around the casing inlet, each conduit coupling structure configured to be coupled to a liquid flow circuit.

[0134] EMBODIMENT 32. 34. The cyclic flow device of any one of claims 28 to 31 and 33, wherein the actuator is configured to cause the bladder to cyclically accumulate and release liquid.

[0135] EMBODIMENT 33. 33. The cyclic flow device of any one of claims 28 to 32, wherein the cyclic flow device is a retrofit device.

[0136] EMBODIMENT 34. a housing defining a first variable volume and a first flow opening extending into the first variable volume, the housing including a movable sidewall defining the first variable volume; an actuator operatively coupled to the movable sidewall; a flow sensor configured to sense a flow rate of the liquid; a controller in data communication with the flow sensor and in operative communication with the actuator, the controller being configured to operate the actuator to determine a flow rate of the liquid relative to the flow sensor; A cyclic flow device comprising:

[0137] EMBODIMENT 35. 47. The cyclic flow device of any one of claims 34 and 36-46, wherein the movable side wall comprises a piston.

[0138] EMBODIMENT 36. 47. The cyclic flow device of any one of claims 34-35 and 37-46, wherein the piston defines an opening and a media-binding structure around the opening.

[0139] 37. 47. The cyclic flow device of any one of claims 34-36 and 38-46, wherein the flow sensor is located on the piston.

[0140] 38. 47. The cyclic flow device of any one of claims 34-37 and 39-46, wherein the flow sensor is located adjacent the first flow opening.

[0141] 39. 47. The periodic flow device of any one of claims 34 to 38 and 40 to 46, wherein the actuator is a linear actuator.

[0142] EMBODIMENT 40. 47. The cyclic flow device of any one of claims 34-39 and 41-46, wherein the actuator is configured to operate a flow control valve.

[0143] EMBODIMENT 41. 47. The cyclic flow device of any one of claims 34-40 and 42-46, wherein the housing includes a first conduit coupling structure around the first flow opening, the first conduit coupling structure configured to sealably couple to the liquid flow circuit.

[0144] EMBODIMENT 42. 47. The cyclic 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.

[0145] EMBODIMENT 43. 47. The cyclic flow device of any one of claims 34-42 and 44-46, wherein the first flow opening is a flow inlet and the first flow opening is not a flow outlet.

[0146] EMBODIMENT 44. 47. The cyclic flow device of any one of claims 34-43 and 45-46, wherein the housing has a complementary variable volume and the movable sidewall defines a complementary variable volume.

[0147] EMBODIMENT 45. 47. The cyclic flow device of any one of claims 34 to 44 and 46, wherein the housing has a second flow opening extending into a complementary variable volume.

[0148] EMBODIMENT 46. 46. ​​The cyclic flow device of any one of claims 34 to 45, wherein the cyclic flow device is a retrofit device.

[0149] One or more of the components, such as the controllers, sensors, detectors, or systems described herein, may include a processor, such as a central processing unit (CPU), computer, logic array, or other device capable of directing data to and from the component. The processor may include one or more computing devices having memory, processing, and communication hardware. The processor may include circuitry used to couple the various components of the controller or with other components operably 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.

[0150] A 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. Functionality attributed to a processor herein may be embodied as software, firmware, hardware, or any combination thereof.

[0151] In one or more embodiments, the functions 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. The program code and / or logic described herein may be applied to input data / information to perform the functions described herein and 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 applied in a known manner. In view of the above, it will be readily apparent that the controller functions described herein may be implemented in any manner known to one of ordinary skill in the art.

[0152] It should also be noted that, as used herein and in the appended claims, the phrase "configured" describes a system, apparatus, or other structure that is constructed to perform a particular task or adopt a particular configuration. The term "configured" can be used interchangeably with similar words, such as "arranged," "constructed," "manufactured," and the like.

[0153] All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this technology 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 by reference. In the event of a conflict between the disclosure of this application and the disclosure of a document incorporated by reference herein, the disclosure of this application shall govern.

[0154] This application is intended to cover adaptations or variations of the subject matter. The above description is intended to be illustrative and not limiting, and it is to be understood that the claims are not limited to the illustrative embodiments described herein. For the purposes of this specification and the appended claims, unless otherwise indicated, all numerical values ​​are understood to be modified in all cases by the term "about". Also, all ranges include the maximum and minimum points disclosed, and any intermediate ranges therein that may or may not be specifically recited herein. Thus, in this context, values ​​referred to herein include a deviation of ±3%. Within this context, the values ​​stated are considered to include values ​​that are within the normal standard error of measurement for the property they modify.

Claims

1. a housing having a first variable volume and a first flow opening extending into said first variable volume, said housing comprising a movable sidewall defining said first variable volume and a first conduit coupling structure around said first flow opening, said movable sidewall being a piston; A linear actuator fixed to the movable side wall; A cyclic flow device comprising:

2. A periodic flow device as described in claim 1, wherein the piston has a media opening defining a flow path fluidly connected to the first variable volume, and the piston has a media coupling structure surrounding the media opening.

3. The periodic flow device of claim 1, wherein the first flow opening is a flow inlet and a flow outlet.

4. The periodic flow device of claim 1, wherein the first flow opening is a flow inlet and the first flow opening is not a flow outlet.

5. The periodic flow device of claim 1, wherein the housing has a complementary variable volume and the movable side wall defines the complementary variable volume.

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