Peristaltic pump with reduced pulsation

Abstract

Systems and methods for reducing pulsation in peristaltic pumps are disclosed. In some examples, the cartridge includes a housing and a flexible sheet coupled to the housing, wherein a transition region of the flexible sheet includes at least one ridge having a maximum height at a location offset from the centerline of the housing transition channel. In some examples, the housing transition channel includes sidewalls that taper toward the active area of ​​the fluid path and / or toward the bottom of the transition channel. An example method of operating a peristaltic pump includes operating a roller at a higher speed during a rotating portion that would otherwise result in a below-average flow rate, and operating the roller at a lower speed during a rotating portion that would otherwise result in an above-average flow rate.

Description

Technical Field

[0001] This disclosure relates to systems and methods associated with peristaltic pumps, for example, used during ophthalmic surgery. Background Technology

[0002] In ophthalmic surgical procedures, fluids are often aspirated from the eye during the procedure. For example, in vitreoretinal surgery, a device can be used to aspirate vitreous material from the eye. As another example, in cataract surgery, a device can be used to break up or emulsify the lens and aspirate the broken up or emulsified lens from the eye.

[0003] In addition, in some ophthalmic surgical procedures, it may be desirable to inject fluids into the eye. For example, in vitreoretinal surgery, cataract surgery, or other procedures, balanced salt solution (BSS) or other irrigation fluids may be introduced into the eye. The fluid may be removed during the procedure as part of the aspiration process.

[0004] In such ophthalmic surgical procedures, peristaltic pumps can be used to aspirate and / or inject fluids. Peristaltic pumps are positive displacement pumps, and because of the limited contact between the pump and the fluid, they are frequently used in medical devices. In a typical design, the pumped fluid only comes into contact with easily removable components of the pump system. To achieve flow, the fluid is contained within a flexible conduit that partially collapses to the point of blocking flow. The sealing point moves along the conduit in the direction of flow. To achieve unrestricted flow, this deformation of the conduit is repeatedly created at multiple locations along the conduit, for example, by using a set of rollers mounted on a rotating hub, with the flexible conduit located near the rollers.

[0005] In some prior art systems, peristaltic pumps include an elastic sheet coupled to a rigid housing, wherein one or more fluid channels are formed in the space between the elastic sheet and the housing. Rollers mounted on a rotating hub compress the elastic sheet to produce a pumping action.

[0006] Prior systems for fluid aspiration and / or injection using peristaltic pumps are disclosed in the following patents: U.S. Patent Nos. 6,261,283, 6,293,926, 6,572,349, 6,632,214, 6,740,074, 6,902,542, 6,962,488, 7,393,189, 7,775,780, 8,011,905, 8,545,198, 8,790,096, 9,482,216, and 9,931,447, the disclosures of which are incorporated herein by reference in their entirety.

[0007] Typically, in peristaltic pumps, the flow is a non-constant, periodic flow. For example, the flow profile typically repeats as it passes through each roller. Previous attempts have been made to reduce pulsation in peristaltic pumps to achieve more stable flow rates. For instance, U.S. Patent No. 6,293,926 discloses an elastic sheet with a tapered channel transition region, wherein the channel transition region of the elastic sheet has an internal cross-section that gradually changes from zero to the full cross-section of the channel. U.S. Patent No. 7,775,780 discloses a housing in which the bottom surface of the channel transition region in the housing tapers toward the elastic sheet to correspond to the shape of the tapered channel transition region of the elastic sheet, so as to provide a transition channel region with a relatively constant cross-section between the housing and the sheet. U.S. Patent No. 8,790,096 discloses other designs aimed at reducing pulsation, such as a peristaltic pump with two pump conduit sections, wherein the rollers acting on one pump conduit section are out of phase with the rollers acting on the other pump conduit section.

[0008] While these previous designs have had some success in reducing pulsation in peristaltic pumps, improvements are still needed to reduce pulsation in peristaltic pumps. Summary of the Invention

[0009] This disclosure relates to improved systems and methods for reducing pulsation in peristaltic pumps.

[0010] In some example embodiments, the cartridge for a peristaltic pump in an ophthalmic surgical system includes a cartridge body and a flexible sheet coupled to the cartridge body, wherein a transition region of the flexible sheet includes at least one ridge having its maximum height at a location offset from the centerline of the transition channel of the cartridge body. The transition region of the flexible sheet may include a notch located above the centerline of the transition channel of the cartridge body. The sheet thickness at the ridge may be greater than the sheet thickness at the notch.

[0011] In some example embodiments, the transition region of the flexible sheet may include multiple ridges having their maximum height at a location offset from the centerline of the transition channel of the housing. The transition region of the flexible sheet may include two ridges, each having its maximum height at a location offset from the centerline of the transition channel of the housing. One of the two ridges may be on one side of the notch, and the other ridge may be on the opposite side of the notch. The two ridges of the transition region of the flexible sheet may be merged into a single ridge within the active area of ​​the flexible sheet.

[0012] In some example embodiments, the cartridge of a peristaltic pump for an ophthalmic surgical system includes a cartridge body and a flexible sheet connected to the cartridge body, wherein a fluid path transition channel of the cartridge body includes a first end adjacent to a port, a second end adjacent to an active area, and sidewalls, and wherein the distance between the sidewalls gradually decreases towards the second end. In some example embodiments, the distance between the sidewalls gradually decreases towards the bottom of the fluid path transition channel of the cartridge body.

[0013] In some example embodiments, the method of operating a peristaltic pump includes operating the set of rollers at a speed above the rated speed during a rotational portion of the set of rollers where operating at the rated speed would result in a below-average fluid flow rate, and operating the set of rollers at a speed below the rated speed during a rotational portion of the set of rollers where operating at the rated speed would result in a above-average fluid flow rate. The set of rollers may operate in multiple compensation cycles, wherein each compensation cycle reaches a speed above the rated speed and then reaches a speed below the rated speed. The set of rollers may operate in multiple compensation cycles per revolution of the set of rollers. In some example embodiments, the number of compensation cycles per revolution of the set of rollers may be equal to the number of rollers in the peristaltic pump multiplied by the number of pump sections in the peristaltic pump.

[0014] In some example embodiments, the set of rollers operates according to a compensation curve that determines the speed of the set of rollers. The compensation curve can be a fixed curve or a varying curve. For example, the compensation curve can vary depending on the speed of the set of rollers. The compensation curve can be determined during or before peristaltic pump operation. The compensation curve can be associated with a marking located on a removable portion of the peristaltic pump.

[0015] Those skilled in the art will understand these and other examples based on this disclosure. Attached Figure Description

[0016] The accompanying drawings illustrate examples of the systems and methods disclosed herein and, together with the specification, serve to explain the principles underlying this disclosure.

[0017] Figure 1aA front view of an elastic sheet having two pump conduit sections is shown, as disclosed in U.S. Patent No. 8,790,096.

[0018] Figure 1b It demonstrates what is disclosed in U.S. Patent No. 8,790,096. Figure 1a Rear view of the elastic sheet.

[0019] Figure 1c A front view of a housing with two pump conduit sections is shown, as disclosed in U.S. Patent No. 8,790,096.

[0020] Figure 1d It demonstrates what is disclosed in U.S. Patent No. 8,790,096. Figure 1c The rear view of the box.

[0021] Figure 2 Showed along Figure 1c The section cut by line 2-2 in the figure shows a cross-sectional view at this plane, where Figures 1a to 1b The elastic sheet is assembled in Figures 1c to 1d On the box.

[0022] Figure 3 A cross-sectional view of a portion of a first example of a peristaltic pump according to this disclosure is shown.

[0023] Figure 4 A top view showing a portion of a second example of a peristaltic pump according to this disclosure.

[0024] Figure 5 Showing Figure 4 An enlarged view of the fluid path transition channel in the box.

[0025] Figure 6 A graph comparing a previous peristaltic pump system operating at a constant speed with a peristaltic pump operating at a variable speed according to this disclosure is shown.

[0026] Figure 7 A graph showing the compensation curves for operating a peristaltic pump at varying speeds, according to this disclosure.

[0027] The accompanying drawings can be better understood by referring to the following detailed description. Detailed Implementation

[0028] For the purpose of explaining the principles of this disclosure, reference is made to the accompanying drawings, which will be described using specific language. However, it should be understood that this is not intended to limit the scope of this disclosure. Those skilled in the art to which this disclosure relates will generally be fully capable of conceiving any changes and further modifications to the described systems, apparatuses, devices, and methods, as well as any further applications of the principles of this disclosure. In particular, a feature, component, and / or step described as an example with respect to this disclosure may be combined with features, components, and / or steps described as examples with respect to this disclosure. For simplicity, in some cases, the same reference numerals are used in all the drawings to refer to the same or similar parts.

[0029] Figures 1a to 1d Examples include U.S. Patent No. 8,790,096. Figures 1a to 1d The flexible sheet 107 and rigid housing 105 are shown. The flexible sheet 107 and housing 105 can form part of a housing for a peristaltic pump used in an ophthalmic surgical system, for example, part of a housing for an ophthalmic surgical console. As used herein, the term "housing" refers to a component of the peristaltic pump that includes a fluid path for pumping action; the housing may or may not be removed from the ophthalmic surgical console. The ophthalmic surgical console can be similar to the ophthalmic surgical console shown and described in U.S. Patent No. 9,931,447. The ophthalmic surgical console can be similar to known and used ophthalmic surgical consoles (e.g., available from Alcon Laboratories, Inc., Fort Worth, Texas). The vision system may be available from Alcon Laboratories, Inc. (Fort Worth, Texas, USA). (Visual system), or any other ophthalmic surgical console suitable for using the principles described herein.

[0030] An ophthalmic surgical console typically includes one or more systems that can be used to perform ophthalmic surgical procedures. For example, the console typically includes a jet system that may include an aspiration system for drawing fluid from the eye and an injection system for injecting fluid into the eye. The jet system may be similar to the jet system shown and described in U.S. Patent No. 9,931,447, or similar to known and used systems such as those described in U.S. Patent No. 9,931,447. visual system or A jet system in a vision system, or any other jet system similar to those suitable for using the principles described herein.

[0031] like Figures 1a to 1dThe sheet 107 and housing 105 shown can form part of a cartridge that can be used in a jet system for an ophthalmic surgical console. The cartridge can be similar to a jet system as shown and described in U.S. Patent No. 9,931,447, or similar to those known and used in, for example... visual system or The vision system can be a jet system, or any other jet system suitable for using the principles described herein. The control console may have a set of rollers mounted for rotation on a rotating hub. The hub and rollers, along with the housing (or part of the housing), can together form a peristaltic pump (and may also include other components, such as a peristaltic pump motor).

[0032] Sheet 107 can be made of a flexible material such as silicone rubber or thermoplastic elastomer. Other flexible materials may also be used. When used with respect to the sheet described herein, the term "flexible" means that the sheet has sufficient flexibility to deform for pumping action. Sheet 107 can be one or more sheets. The sheet can be made by molding or any other suitable method.

[0033] The housing 105 may be made of a rigid material, such as a rigid thermoplastic, like polycarbonate and / or polysulfone, to provide rigidity and structural integrity. The housing 105 may be a one-piece or multi-piece construction. The housing may be manufactured by injection molding, machining, or any other suitable method. The housing 105 may have a pump interface portion, which may be joined by a resilient sheet 107 to form a pump fluid path, wherein the pump section of the sheet will be engaged by pump rollers. Sections of the suction flow path and / or injection flow path may extend as channels and / or tubes within the housing 105.

[0034] The box body 105 may have holes and / or notches for aligning the box with the console when it is inserted into the console. In some examples, the box may be a removable, disposable, or consumable item that can be used for a single patient procedure. A new box can be used for a new procedure.

[0035] As described in U.S. Patent No. 8,790,096, sheet 107 is adapted to be coupled to housing 105 to define two or more pump fluid paths for the coupled sheet 107 and housing 105 in areas designated as sheet pump sections 103a, 103b (collectively, pump section 103). In some examples, sheet 107 may be adhesively or mechanically attached to housing 105 (e.g., by adhesive, heat fusion, mechanical crimping, riveting, etc.). In some examples, protrusions on the outer periphery and / or interior of sheet 107, such as protrusions designated 151a-151n, may engage corresponding recesses, such as recesses on housing 105 designated 153a-153n, to connect sheet 107 to housing 105 and help prevent sheet 107 from rotating when subjected to roller action.

[0036] As in Figure 1c and Figure 1d As can be seen, the housing 105 has a front surface 121 and a rear surface 123. The front surface 121 has a pump interface portion 109, which includes housing fluid paths 125a and 125b. Housing fluid path 125a includes an inlet port 112a and an outlet port 112b, a housing fluid path active region 163, a housing fluid path transition region 127a between the inlet port 112a and the housing fluid path active region 163, and a housing fluid path transition region 127b between the outlet port 112b and the housing fluid path active region 163. Housing fluid path 125b includes an inlet port 112c and an outlet port 112d, a housing fluid path active region 165, a housing fluid path transition region 127c between the inlet port 112c and the housing fluid path active region 165, and a housing fluid path transition region 127d between the outlet port 112d and the housing fluid path active region 165. Each of the fluid path transition regions 127a, 127b, 127c, and 127d includes fluid path transition channels 157a, 157b, 157c, and 157d, which are recessed relative to the adjacent fluid path activity region 163 or 165.

[0037] As in Figure 1a and Figure 1b As can be seen, the flexible sheet 107 has a front surface 131 and a rear surface 133. The flexible sheet 107 includes sheet pump sections 103a and 103b. The rear surfaces of each sheet pump section 103a and 103b define sheet fluid paths 135a and 135b, respectively. The front surfaces of each sheet pump section 103a and 103b include roller engagement surfaces 137a and 137b, respectively. The sheet pump section 103a includes a sheet pump section active region 143 adapted to be positioned above the fluid path active region 163 of the housing, a sheet pump section transition region 147a adapted to be positioned above the fluid path transition region 127a of the housing, and a sheet pump section transition region 147b adapted to be positioned above the fluid path transition region 127b of the housing. The sheet pump section 103b includes a sheet pump section active region 145 adapted to be positioned above the fluid path active region 165 of the housing, a sheet pump section transition region 147c adapted to be positioned above the fluid path transition region 127c of the housing, and a sheet pump section transition region 147d adapted to be positioned above the fluid path transition region 127d of the housing.

[0038] exist Figures 1a to 1dIn the example, protrusions 117a and 117b on the sheet 107 (which can outline corresponding sheet fluid paths 135a and 135b) can be fitted into corresponding grooves 119a and 119b in the housing 105 (which can outline corresponding housing fluid paths 125a and 125b). When the flexible sheet 107 is connected to the housing 105, the sheet fluid path 135a connects with the housing fluid path 125a to form a first pump fluid path, and the sheet fluid path 135b connects with the housing fluid path 125b to form a second pump fluid path.

[0039] Protrusions 117a, 117b can be secured to corresponding recesses 119a, 119b to retain sheet 107 in housing 105. In some examples, protrusions 151a-151n and / or protrusions 117a, 117b can be secured to corresponding recesses 153a-153n and / or recesses 119a, 119b by mechanical / friction fit, adhesive, heat fusion, etc. In some examples, protrusions 117a, 117b can be secured to corresponding recesses 119a, 119b to form a seal, thereby preventing pump fluid from leaking from the pump fluid path.

[0040] As described in U.S. Patent No. 8,790,096, fluid can be pumped through a cartridge when a series of rollers engage two or more pump sections 103a, 103b. The rollers can be mounted radially from the axis of rotation of a peristaltic pump motor (e.g., a stepper or DC servo motor, or other motors such as AC motors) and can be configured to press the pump sections 103 of sheet 107 against the underlying cartridge housing 105. The first and second pump fluid paths (125a and 135a, 125b and 135b) can be fluidly connected to ports in the cartridge housing 105, such as ports 112a, 112b, 112c, 112d (collectively referred to as port 112). Port 112 a-112d can provide corresponding inlets and outlets for the fluid being pumped through the pump fluid path. As the rollers roll past and away from the inlet ports (e.g., inlet ports 112a, 112c), the corresponding fluid clumps can be drawn through the inlet ports into the corresponding pump fluid paths (125a and 135a, 125b and 135b) (due to the vacuum created by the rollers pushing the fluid away from the inlet). As the rollers approach and roll past the outlet ports (e.g., outlet ports 112b, 112d), the corresponding fluid clumps can travel through the outlet ports.

[0041] A single hub roller assembly can act on two (or more) movable pump sections 103 in sheet 107. When the rollers engage pump sections 103, each roller can first roll over a transition region (e.g., transition regions 147a, 147c) having the following transition channels (e.g., transition channels 157a, 157c). In some examples, sheet 107 may not include transition regions 147a-147d, and housing 105 may not include transition channels 157a-157d. As the rollers roll away from transition areas 147a, 147c (and correspondingly, from transition channels 157a, 157c), an internal seal can be formed within the pump section 103 (e.g., at point 161 indicated by the dashed line on pump section 103a or point 169 on pump section 103b) by fully pressing the sheet 107 onto the housing 105 at the sealing point (in the absence of transition areas and transition channels, the rollers can form a seal at the point where the rollers engage with the sheet 107). The internal seal can move as the rollers roll through “active” areas 163 or 165. With the movement of the rollers, fluid preceding the roller movement can be pushed across pump section 103, causing fluid following the roller movement to be drawn from the inlets (e.g., inlets 112a, 112c). As the next roller on the roller head approaches the transition regions 147a, 147c (above transition channels 157a, 157c) behind the roller currently forming the internal seal, the next roller can begin to reduce the cross-sectional space between the sheet 107 below the non-sealing roller and the housing 105. Due to the geometry of the transition regions 147a, 147c and the underlying transition channels 157a, 157c, the non-sealing roller on the transition regions 147a, 147c can have fluid under the roller (e.g., in the transition channels 157a, 157c), thereby preventing a seal. As the cross-sectional space decreases (e.g., when the non-sealing roller approaches the sealing point or starting point of the active regions 163, 165), the fluid drawn by the sealing roller can be slowly constrained. Due to the sealing of the movable roller, the transition roller can slowly reduce the fluid flow from the inlet until the transition roller forms a new seal at sealing point 161 (or 169) and becomes a new movable roller (effectively isolating the previous sealing roller). This sequence can then be repeated when the next roller on the roller head engages at the starting point of transition areas 147a, 147c (above transition channels 157a, 157c).

[0042] The sequence of rollers engaging transition regions 147a, 147c (above transition channels 157a, 157c) and then forming a moving internal seal (where subsequent rollers slowly reduce fluid flow until a seal is formed) can result in periodic variations (or “pulses”) in the fluid flow / pressure profile of the fluid being pulled from inlets (e.g., inlets 112a, 112c) and / or pushed to outlets or discharge ports (e.g., outlets or discharge ports 112b, 112d).

[0043] Figure 2 Showed along Figure 1c The cross-sectional view taken by line 2-2 in the figure shows the cross-sectional view at this plane, where, Figures 1a to 1b The sheet 107 is assembled in Figures 1c to 1d On the box body 105. The protrusion 117a of the sheet 107 can be seen in the groove 119a of the box body 105. Figure 2 Line 159 marks the centerline of the fluid path transition channel 157a within the housing. (As shown in...) Figure 2 As can be seen, the pump section 103a of sheet 107 has a raised central portion 171 that protrudes beyond the center of the fluid path transition channel 157a of housing 105. As the pump section 103a of sheet 107 continues from the starting point of the fluid path transition channel 157a to the starting point of the active region 163, the height of the raised central portion 171 gradually increases to a single ridge of full height above the active region 163. The raised central portion 171 continues as a single ridge of full height through the active region 163 to the fluid path transition channel 157b. As the pump section 103a of sheet 107 continues from the starting point of the fluid path transition channel 157b to the outlet 112b, the height of the raised central portion gradually decreases. Above the outlet 112b, the contour of the elastic sheet 107 is consistent with... Figure 2 The outline above the inlet 112a is similar. The geometry of pump section 103b is the same as that of pump section 103a.

[0044] Figure 3 A cross-sectional view of a portion of a first example of a peristaltic pump according to this disclosure is shown. Figure 3 It shows something similar to Figure 2 The view shows a sheet 207 on a housing 205. The housing 205 may be similar to the housing 105 and have all its features. The sheet 207 may be similar to the sheet 107 and have all its features, except that the profile of the sheet pump section transition region of the pump section of the sheet 207 differs from that of the sheet pump section transition regions 147a-147d of the pump sections 103a and 103b of the sheet 107.

[0045] As in Figure 3As can be seen, in the region above inlet 212a, the pump section 203a of sheet 207 has a sheet pump section transition region 247a, which has two raised side ridges 209 protruding on either side of the central portion 208 of sheet 207, wherein the central portion 208 of sheet 207 is the portion of sheet 207 above the fluid path transition channel 257a of the housing. The central portion 208 of sheet 207 is recessed relative to the two raised side ridges 209 on either side of the central portion 208. The central portion 208 includes a notch located above the centerline 259 of the fluid path transition channel 257a of the housing.

[0046] As in Figure 3 As can be seen, the sheet pump section transition region 247a includes at least one ridge 209, and in this example, two ridges 209, which have a maximum height 209H at a location offset from the centerline 259 of the fluid path transition channel 257a. In this example, the height of a point on the sheet 207 represents the height of the front surface of the sheet 207, which is measured from the surface of the box 205 at a horizontal plane in the fluid path activity area of ​​the box, resulting in the height 209H of each ridge 209.

[0047] The thickness of the sheet pump section transition region 247a at each ridge 209 is greater than the thickness of the region at the notch at the central portion 208. In the example shown, at each ridge 209, the thickness of the sheet 207 extends over the entire range of the height 209H of the ridge 209. In other examples, the rear surface of the sheet 207 may protrude beyond the horizontal plane of the fluid path active area of ​​the housing, such that the thickness of the ridge may be less than the height of the ridge measured from the horizontal plane of the fluid path active area of ​​the housing.

[0048] The transition area of ​​the flexible sheet 207 may include multiple ridges, which have their maximum height at a location offset from the centerline of the transition channel of the housing 205. In the example shown, one of the two ridges 209 is on one side of the notch 208, and the other ridge of the two ridges 209 is on the opposite side of the notch 208. Other numbers and placements of ridges are possible in other examples.

[0049] As the pump section 203a of sheet 207 continues from the starting point of the box fluid path transition channel 257a at inlet 212a to the box fluid path active area (corresponding to...) Figure 1c At the starting point of the active region 163, the height of the raised side ridges 209 gradually decreases until they no longer exist as raised side ridges in the active region. Similarly, as the pump section 203a of the sheet 207 approaches the active region of the fluid path in the housing (corresponding to...), the height of the raised side ridges 209 gradually decreases until they no longer exist as raised side ridges in the active region. Figure 1cStarting from the active area 163), the height of the recessed central portion 208 gradually increases until it becomes the full-size central area above the fluid path active area of ​​the box. The sheet pump section active area of ​​pump section 203a (located corresponding to...) Figure 1c The active area 163 of the sheet 207 (above the active area of ​​the fluid path in the box) has a similar profile to the active area 143 of the sheet pump section 103a, wherein the central portion of a single protrusion is aligned above the center of the active area of ​​the fluid path in the box. As the pump section 203a of the sheet 207 continues from the starting point of the fluid path transition channel 257a at the inlet 212a to the starting point of the active area of ​​the fluid path in the box, the two ridges 209 of the sheet pump section transition area 247a merge into a single ridge in the active area of ​​the sheet pump section.

[0050] The tail transition region of pump section 203a from the active area to the outlet is similar to the transition region of pump section 203a from the inlet to the active area. From the active area to the outlet, the height of the raised central portion gradually decreases until this portion becomes the recessed central portion 208 above the outlet, similar to... Figure 3 The recessed central portion 208 is located above the central inlet 212a. Similarly, from the active area to the outlet, lateral ridges form and increase in height until these lateral ridges constitute the full height of the two raised lateral ridges 209, as shown in... Figure 3 This can be seen from the text.

[0051] The sheet 207 has a second pump section 203b similar to pump section 103b, except that the second pump section is the same as the pump section 103b and the pump section 203a is the same as the pump section 103a. The geometry of pump section 203b is the same as that of pump section 203a.

[0052] Figure 3 The contour of the elastic sheet 207 in the pump helps reduce pulsation in the peristaltic pump. Figure 2 In the example, as the roller rolls over the inlets 112a, 112c and the transition region, the roller presses the raised central portion 171 downwards and into the fluid path transition channels 157a, 157c of the housing, which may cause or facilitate pulsating flow. Similarly, in Figure 2 In the example, as the roller rolls over the transition area and outlets 112b, 112d, the roller again presses the raised central portion 171 downwards and into the fluid path transition channels 157b, 157d of the housing, which may cause or facilitate pulsating flow. In contrast, in Figure 3 In this embodiment, as the roller rolls over the inlet and transition region, the roller primarily acts on the raised side ridges 209. The raised side ridges 209 and the corresponding recessed central region 208 help reduce or eliminate the downward protrusion of the central region as the roller passes through the inlet and fluid path transition channel, thereby reducing pulsations in the flow. Similarly, in Figure 3 In this embodiment, the roller rolls from the active area over the transition area and the outlet, again primarily acting on the raised side ridges 209. The raised side ridges 209 and the corresponding recessed central region 208 help reduce or eliminate the downward protrusion of the central region as the roller passes through the fluid path transition channel and the outlet, thereby reducing pulsations in the flow. The raised side ridges 209 relieve pressure on the central region, helping to prevent the central region from being pushed downwards into the fluid path transition channel, and correspondingly helping to reduce pulsations in the flow rate.

[0053] As an alternative embodiment (not shown), the housing 205 itself may have one or more raised shoulders or ramps in the transition area. These raised shoulders or ramps can help prevent the rollers from pressing excessively on the central area of ​​the flexible sheet. Similar to... Figure 3 In this embodiment, the pressure in the central region of the transition area of ​​the flexible sheet will be reduced, helping to prevent the central region of the flexible sheet from being pushed downward into the fluid path transition channel, and correspondingly helping to reduce pulsations in the flow rate.

[0054] Figure 4 A top view showing a portion of a second example of a peristaltic pump according to this disclosure. Figure 4 In Figure 1c A similar view to the view of housing 105 shows housing 305. Housing 305 may be similar to housing 105 and have all its features, except for the shape of the fluid path transition channel of the housing, as shown in the figure and described below. Housing 305 can be used with any suitable flexible sheet such as sheet 107 or sheet 207.

[0055] The housing 305 has a pump interface portion 309 to which an elastic sheet (e.g., elastic sheet 107 or 207) can be coupled. The pump interface portion 309 has grooves 319a, 319b adapted to receive corresponding protrusions (e.g., protrusions 117a, 117b) of the elastic sheet. The area defined by these grooves 319a, 319b and the corresponding protrusions of the elastic sheet constitutes a region for fluid flow within a fluid path defined by the housing fluid paths 325a, 325b. Fluid flows from inlet 312a to outlet 312b in a first fluid path and from inlet 312c to outlet 312d in a second fluid path.

[0056] The fluid paths 325a and 325b of the housing include similar... Figure 1b The active areas 163 and 165 are active areas 363 and 365. The pump section includes housing fluid path transition channels 357a, 357b, 357c, and 357d designed to reduce pulsation in fluid flow.

[0057] Figure 5 An enlarged view of the fluid path transition channel 357a in the housing is shown. The transition segment 357a includes a bottom surface 381, side walls 382 and 383, top edges of the side walls 384 and 385, a first end 386, and a second end 387. The first end 386 represents the end of the fluid path transition channel 357a adjacent to the inlet 312a, and the second end 387 represents the end of the fluid path transition channel 357a adjacent to the active area 363. The shape of the fluid path transition channel 357a represents the shapes of other fluid path transition channels 357b-357d. In the case of fluid path transition channels at the pump section ends, such as fluid path transition channels 357b and 357d, the first end 386 represents the ends of fluid path transition channels 357b and 357d adjacent to outlets 312b and 312d, respectively.

[0058] As in Figure 4 and Figure 5 As can be seen, sidewalls 382, ​​383 and top edges 384, 385 gradually approach each other as they move away from the first end 386 of the fluid path transition channel 357a and towards the second end 387. Therefore, the width of the fluid path transition channel 357a gradually narrows towards the second end 387 (the width is the dimension through the fluid path transition channel along the radius of the pump interface portion). As in Figure 4 and Figure 5 As can be seen, the distance between the two sidewalls 382 and 383 gradually changes towards the second end 387. Furthermore, the sidewalls 382 and 383 are inclined, such that the sidewalls 382 and 383 are closer together at the bottom surface 381 than at the top where they intersect with the top edges 384 and 385 of the sidewalls. (As shown in...) Figure 4 and Figure 5 As can be seen, the distance between the two sidewalls 382 and 383 gradually changes towards the bottom 381 of the fluid path transition channel 357a. The bottom surface 381 also slopes upward towards the second end 387. The other fluid path transition channels 357b-357d have the same shape as the fluid path transition channel 357a.

[0059] In previous designs, for example Figure 1c In the housing, although it has an upwardly sloping bottom surface at the end of the transition channel 157a-157d towards the housing fluid path (see, for example) Figure 1c The inclined surfaces 158a-158d in the middle, but the fluid path transition channels 157a-157d in the box have a constant width throughout the fluid path transition channels in the entire box. In contrast, in Figures 4 to 5In the design, the width of the fluid path transition channels 357a-357d in the box gradually changes, that is, it narrows towards the end 387 as the side walls 382, ​​383 (and the top edges of the side walls 384, 385) move closer to the end 387. In addition, due to the slope of the side walls 382, ​​383, the width of the fluid path transition channels 357a-357d in the box is narrower at the bottom than at the top.

[0060] Considering such Figures 4 to 5 The geometry shown allows for smoother and gentler fluid flow in and out of the active area. The gradients of the sidewalls 382 and 383 towards the ends 387 of the fluid path transition channels 357a-357d and towards the bottom 381 create a smoother and gentler flow in and out of the active area. This smoother and gentler flow reduces the pulsations that might exist in the flow in the previous geometry.

[0061] Figure 6 A graph comparing a previous peristaltic pump system operating at a constant speed with a peristaltic pump operating at a varying speed according to this disclosure is shown. Figure 6 In the graph, the example of a previous peristaltic pump system (labeled "constant speed") has two pump sections and seven rollers, similar to those described in U.S. Patent No. 8,790,096. The rollers are operated by a stepper motor, which in this example takes 200 steps per revolution of the set of rollers. Each roller travels twice across each of the two pump sections per revolution. Figure 6 As can be seen, this example system previously generated a pulsating flow, ranging from as low as approximately 9.5 mL / min to as high as approximately 13.8 mL / min. The flow was cyclical, with 14 highs and 14 lows, representing the rollers passing through the pump section 14 times (each of the 7 rollers passing through 2 pump sections). As shown in... Figure 6 As can be seen, each of the other low points looks different, with one set of low points ranging from about 9.5 ml / min to about 9.8 ml / min, and another set of low points ranging from about 10.5 ml / min to about 10.8 ml / min, indicating a difference between the two pump segments.

[0062] According to this disclosure, the speed of the motor in the peristaltic pump system is modulated based on the measured flow output. The motor operates faster in the measured low flow range and slower in the measured high flow range. Figure 7 A graph showing the speed adjustment factor of a peristaltic pump operating at varying speeds according to this disclosure is provided. Based on measured flow output, the motor speed is continuously adjusted to a speed between approximately 0.75 times and 1.15 times the rated operating speed. (As shown in...) Figure 7 As can be seen, the compensation is carried out in a cycle that reflects the pulsating flow. Among them, 14 adjustments above the rated speed and 14 adjustments below the rated speed represent the rollers passing through the pump section 14 times (each of the 7 rollers passes through 2 pump sections).

[0063] As in Figure 6 It can be seen from this that, when based on Figure 6 The compensation curve ( Figure 6 When operated at a varying rate (marked as "variable speed"), the resulting fluid flow is smoother and pulsation is reduced. The system produces flow rates within a narrow range of approximately 12 ml / min ± 0.2 ml / min.

[0064] According to this disclosure, a method of operating a peristaltic pump includes rotating the set of rollers such that each roller rotates once around the pump section during each rotation of the set of rollers; operating the set of rollers at a speed higher than the rated speed during a rotational portion where operating the set of rollers at the rated speed would result in a below-average fluid flow rate; and operating the set of rollers at a speed lower than the rated speed during a rotational portion where operating the set of rollers at the rated speed would result in a above-average fluid flow rate. The rotational portion during which the set of rollers operates at a speed higher than the rated speed need not be all the portions of rotation where operating the set of rollers at the rated speed would result in a below-average fluid flow rate. Similarly, the rotational portion during which the set of rollers operates at a speed lower than the rated speed need not be all the portions of rotation where operating the set of rollers at the rated speed would result in a above-average fluid flow rate.

[0065] The operation of this set of rollers can be performed in multiple compensation cycles, each cycle reaching a speed above the rated speed and then below the rated speed. The set of rollers can operate in multiple compensation cycles per revolution of the set of rollers. In some embodiments, the number of compensation cycles per revolution of the set of rollers is equal to the number of rollers in the peristaltic pump multiplied by the number of pump sections in the peristaltic pump. For example, in Figure 6 and Figure 7 In the example, the peristaltic pump has seven rollers and two pump sections, and the compensated cycles per revolution of this set of rollers are fourteen, as in... Figure 7 This can be seen from the text.

[0066] The operation of this set of rollers can be performed based on the compensation curve that determines the speed of this set of rollers, for example... Figure 7 The compensation curve shown can be a fixed curve during pump operation, or it can vary depending on the speed of the set of rollers.

[0067] In some embodiments, the compensation curve can be determined during operation of the peristaltic pump. For example, the flow rate can be measured and the roller speed adjusted in real time. As another example, the flow rate can be measured and the roller speed adjusted based on one or more recent pump cycles. In other embodiments, the compensation curve can be determined before operation of the peristaltic pump. For example, the compensation curve can be determined during testing of the peristaltic pump or similar testing methods.

[0068] The compensation curve can be associated with a marking located on a removable part of the peristaltic pump. For example, the box can have a barcode or other machine-readable marking that informs the control console of the compensation curve.

[0069] Those skilled in the art will understand that the embodiments covered by this disclosure are not limited to the specific exemplary embodiments described above. In this regard, although several illustrative embodiments have been shown and described, various modifications, alterations, and substitutions are contemplated in the foregoing disclosure. It should be understood that such changes can be made to the foregoing without departing from the scope of this disclosure. Therefore, it should be understood that the appended claims should be interpreted broadly and in accordance with the content of this disclosure.

Claims

1. A cassette for a peristaltic pump of an ophthalmic surgical system, the cassette comprising: a cassette body having a front surface and a back surface, wherein the front surface of the cassette body comprises a cassette body fluid path, wherein the cassette body fluid path comprises a plurality of ports, a cassette body fluid path active area, and a cassette body fluid path transition area between one of the plurality of ports and the cassette body fluid path active area, wherein the cassette body fluid path transition area comprises a cassette body fluid path transition channel that is recessed relative to the cassette body fluid path active area; and a flexible sheet coupled to the cassette body, wherein the flexible sheet comprises a sheet pump segment having a back surface comprising a sheet fluid path and a front surface comprising a roller engagement surface, wherein the sheet fluid path connects with the cassette body fluid path to form a pump fluid path when the flexible sheet is coupled to the cassette body, wherein the sheet pump segment comprises a sheet pump segment active area positioned over the cassette body fluid path active area and a sheet pump segment transition area positioned over the cassette body fluid path transition area; wherein the sheet pump segment transition area comprises at least one ridge on the front surface of the sheet pump segment that has its maximum height at a location that is offset from a centerline of the cassette body fluid path transition channel; wherein the sheet pump segment transition area comprises two ridges on the front surface of the sheet pump segment, each of the two ridges having its maximum height at a location that is offset from a centerline of the cassette body fluid path transition channel; wherein the sheet pump segment transition area comprises a notch at a location over the centerline of the cassette body fluid path transition channel; wherein one of the two ridges is on one side of the notch and the other of the two ridges is on an opposite side of the notch; wherein the two ridges of the sheet pump segment transition area merge into a single ridge in the sheet pump segment active area.

2. The cassette for a peristaltic pump of an ophthalmic surgical system of claim 1, wherein, a thickness of the sheet pump segment transition area at the at least one ridge is greater than a thickness at the notch.

3. The cassette for a peristaltic pump of an ophthalmic surgical system of claim 1, wherein, a height of the notch on the sheet pump segment transition area increases until it reaches a full-size center area over the cassette body fluid path active area.

4. The cassette for a peristaltic pump of an ophthalmic surgical system of claim 3, wherein, a height of the full-size center area decreases until it becomes the notch on the sheet pump segment transition area.

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