`
`[19]
`
`[11] Patent Number:
`
`5,575,631
`
`Jester
`
`[45] Date of Patent:
`
`Nov. 19, 1996
`
`llllllllllllllllillllllllllIllllIllllllllllllllillilllllllllllllllllllllill
`USO05575631A
`
`[54] CURVILINEAR PERISTALTIC PUIVIP
`
`[75]
`
`Inventor: Rogelio Blanco Jester, Mexicali,
`Mexico
`
`[73] Assignee: Ahmad-Maher Moubayed, Mission
`Viejo, Calif.
`
`A9131‘ No‘: 615’704
`[21]
`[22] Filed:
`Mar. 12, 1996
`
`Int. CL6 .................................................... ..
`[52] US. Cl.
`.............................................................. 417/474
`Field of Search ................................... .. 417/474, 478,
`417/479, 480; 604/153
`
`References Cited
`
`U'S' PATENT DOCUMENTS
`4/1964 Voelcker ............................... .. 417/478
`3,127,845
`6/1993 Hyman et al.
`.......................... 417/474
`5,217,355
`FOREIGN PATENT DOCUMENTS
`
`2152352
`582797
`853157
`
`4/1973 Germany .
`9/1958
`Italy .
`8/1981 U.S.S.R.
`
`7/1982 U.S.S.R.
`941672
`Primary Examiner—Timothy Thorpe
`Assistant Examiner—Peter G. Korytnyk
`Attorney, Agent, 0r.Firm—John R. Duncan; Frank D. Gil-
`ham
`[57]
`
`417/474
`
`'
`
`ABSTRACT
`
`A curvilinear peristaltic pump for pum ing liquids throu h
`a resilient tube. The pump includes a culived concave platin
`against which a resilient tube is placed. A multi lobed cam
`is positioned adjacent to the platen and tube. A plurality of
`pump fingers are mounted between the tube and Cam in a
`manner perrnjtting radial movement of the pump fingers_ As
`the cam rotates,
`the fingers are pressed toward the tube
`sequentially so as to pump liquid through the tube. The lobe
`end presses the tube sufiiciently to occlude the tube and
`prevent back flow without over pressing and damaging the
`tube. A transverse pinch finger is provided on each pump
`finger, extending from the tube pressing face of each pump
`finger. At the tube occluding position, the pump finger nearly
`occludes the tube and the pinch finger completes occlusion
`v-vithout pressing the tube beyond the fully occluded posi-
`tion. A fixed or shdable spring pressed pinch finger may be
`used.
`
`20 Claims, 2 Drawing Sheets
`
`ACTA EX. 1013-001
`
`ACTA Ex. 1013-001
`
`
`
`U.S. Patent
`
`69919:1v.0N
`
`Sheet 1 of 2
`
`, 5,575,631
`
`ACTA Ex. 1013-002
`
`
`
`HGURE 4
`
`’HGURE 2
`
`2c
`.<
`F-*
`.‘°
`F-*
`\D
`x:
`ax
`
`ZJ0Z199518
`
`I£9‘sLs‘s
`
`ACTA Ex. 1013-003
`
`
`
`1
`CURVILINEAR PERISTALTIC PUMP
`
`5,575,631
`
`2
`
`BACKGROUND OF THE INVENTION
`
`This invention relates in general to fluid pumps and more
`specifically to a peristaltic pump having a cam driven
`plurality of fingers for sequentially engaging a resilient tube
`to create liquid flow through the tube.
`Conventional linear and rotary peristaltic pumps typically
`have a section of resilient tubing positioned between a wall
`and a, set of rollers or reciprocating pushers that progres-
`sively compress sections of the tubing to pump liquids. Such
`pumps are often used in medical applications, such as
`intravenous infusion or withdrawing fluids such as in a
`wound drainage system. These pumps operate in a positive
`manner and are capable of generating substantial outlet
`pressures.
`
`Typical linear peristaltic pumps include those described
`by Sorg et al. in U.S. Pat. No. 2,877,714, Borsarmyi in U.S.
`Pat. No. 4,671,792 Herninway et al.
`in U.S. Pat. No.
`4,893,991 and Canon in U.S. Pat. No. 4,728,265. While
`generally effective, these pumps are large, complex and
`cumbersome, requiring a drive shaft parallel to a resilient
`tube and a plurality of cams along the drive shaft to move
`pushers toward and away from the tube.
`Rotary peristaltic pumps generally dispose a resilient tube
`along a circular path, with a number of rollers mounted
`around the circumference of a circular rotor sequentially
`rolling along the tube to occlude the tube and force liquid
`through the tube. Typical of such pumps are those disclosed
`by Soderquist et al. in U.S. Pat. No. 4,886,431 and Kling in
`U.S. Pat. No. 3,172,367. These pumps often have relatively
`low efliciency and impose high shear and tension stresses on
`the tube causing internal tube wall erosion or spallation. The
`tube may eventually be permanently deformed so that the
`tube becomes flattened into a more oval shape and carries
`less liquid.
`Another type of peristaltic pump has a tube arranged
`along a circular path with a cam member within the circle
`sequentially moving a plurality of blunt pushers or fingers
`outwardly to sequentially compress the tube from one end of
`the path to the other. Typical of these pumps are those shown
`by Gonner in German Patent No. 2,152,352 and Tubospir in
`Italian Patent No. 582,797.
`
`These pumps tend to be less complex than linear peri-
`staltic pumps. However, the pressure imposed by the blunt
`fingers reduces tube life, sometimes causing internal tube
`wall erosion or spallation, which results in particulate matter
`getting into the fluid stream. Tube with different wall thick-
`nesses cannot be accommodated by these pumps, since with
`thinner than standard tubes the fingers will not properly
`occlude the tube and with thicker than standard tubes the
`tube will close prematurely and be subject to excessive
`compression, requiring higher cam drive power and causing
`excessive wear on the cam and tube.
`
`Thus, there is a continuing need for peristaltic pumps of
`greater simplicity, small size, low drive power requirements
`and which can accommodate resilient tubes of varying wall
`thickness while reducing wear and internal erosion of the
`resilient tube.
`
`SUMMARY OF THE INVENTION
`
`The above-noted problems, and others, are overcome in
`accordance with this invention by a curvilinear peristaltic
`pump having a concave curved, generally circular, platen for
`
`supporting a resilient tube, a multi-lobe cam rotatable about
`the center of the platen concavity, and a plurality of pump
`fingers riding on the cam as cam followers and guided to
`move in a radial direction toward and away from said platen.
`Each pump finger has a face for engaging a tube on said
`circular platen. Each face includes a narrow pinch finger
`spring centered in the face and biased to extend beyond the
`face. Further, each pump finger includes a roller between the
`body of the pump finger and the cam to ride on the cam in
`the manner of a roller bearing, reducing wear.
`When the cam is rotated, the pump finger closest to the
`highest area on the cam (widest lobe) in the direction of
`rotation will be moved outwardly in a radial direction to
`squeeze the tube against the platen. As the cam continues to
`rotate, the second pump finger will squeeze the tube as the
`pinch finger on the first pump finger occludes the tube, to
`force liquid in the tube to flow in the same direction as the
`cam rotates. As cam rotation continues,
`the subsequent
`fingers will sequentially squeeze the tube to push liquid and
`then occlude the tube. At the same time, the pump finger just
`behind the lobe will move away from the tube, allowing the
`tube to expand and fill with liquid. This sequence continues
`as cam rotation proceeds.
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`Details of the invention, and of preferred embodiments
`thereof, will be further understood upon reference to the
`drawing, wherein:
`FIG. 1 is a perspective view of my pump with the casing
`open and partially cut-away and one pump finger and pinch
`finger cut-away;
`FIG. 2 is a side elevation of the pump at the beginning of
`a pumping cycle with the casing closed and the near side
`casing removed to show the internal components;
`'
`FIG. 3 is a detail side elevation view of the pump finger
`assembly having a spring biased pinch finger and with the
`pinch finger partially cut-away; and
`FIG. 4 is a detail side elevation view of a pump finger with
`an alternate pinch finger embodiment.
`
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`Refening to FIGS. 1 and 2, there is seen a curvilinear
`peristaltic pump 10 having a casing basically consisting of
`a front plate 12, a back plate 14 and spacers 16. The casing
`is held together by a plurality of bolts 19 for ease of
`assembly and disassembly as needed. A removable cover 18
`is secured to casing 10. Each spacer 16 includes a block 20
`having a hole therethrough cooperating with a pin or bolt 22
`and hook—shaped cover extensions 24 to hold the cover 18 in
`place.
`Cover 18 includes a concave curvilinear platen 26. While
`platen 26 may have any suitable surface, generally a cylin-
`drical surface is preferred. As best seen in FIGS. 2 and 3, a
`resilient tube 28 may be laid along platen 26, exiting through
`the open space between each pair of extensions 24.
`A multi-lobed cam 30 is mounted for rotation about an
`axle 32 that extends through suitable bearings in front and
`back plates 12 and 14. Cam 30 may have any suitable
`number of lobes, two or more. For optimum performance
`with smallest size, the three-lobe cam shown is preferred.
`Where platen 26 is cylindrical, axle 32 is preferably at the
`axis of the platen. Cam 30 can be rotated in either direction
`to pump liquid through tube 28 in either direction. For
`
`ACTA EX. 1013-004
`
`ACTA Ex. 1013-004
`
`
`
`5,575,631
`
`3
`convenience of operation explanation, cam 30 will be con-
`sidered to be rotating clockwise, as indicated by arrow 34.
`Any suitable drive means may be used to rotate cam 30. In
`the preferred embodiment shown, an electric drive motor 36
`extends through opening 37 in back plate 14 and is mounted
`on .the back surface of front plate 12. Motor 36 has a drive
`shaft 38 extending through front plate 12 to a pulley 40. A
`drive belt 42 extends from pulley 40 to pulley 44 mounted
`on cam axle 32. Pulleys 40 and 44 are sized to provide the
`desired cam rotation speed. A variable speed motor 36 may
`be used to allow cam rotation speed to be easily varied. If
`desired, a gear system could be used in place of belt 42, or
`a dilferent drive system could be used, such as a conven-
`tional hydraulic drive, in place of the electric motor and belt
`drive system shown.
`A plurality of pump fingers 48, as best seen in FIGS. 1 and
`3, are mounted for radial movement on front plate 12 and
`back plate 14 between cam 30 and platen 26. Any suitable
`number of pump fingers 48 may be used. Where a greater
`number of cam lobes are used, fewer fingers will generally
`be used. On the other hand, if narrow fingers 48 are used, a
`larger number may be provided. A large scale pump will
`generally use a larger number of fingers. A preferred number
`of pump fingers 48 for a three-lobe cam 30 of maximum
`efliciency coupled with small size is from 7 to 11 pump
`fingers, with 9 generally being optimum. As seen in FIG. 1,
`a plurality of opposed radial grooves 50 are provided in front
`plate 12 and back plate 14 to receive side extensions 52 that
`extend into grooves 50 and are freely movable therealong.
`Each pump finger 48, as best seen in FIG. 3, includes a
`cylindrical recess 54 at a first end 56 for rotatably receiving
`a bearing roller 58. Rollers 58 freely roll on the surface of
`cam 30 in the manner of roller bearings, reducing wear on
`the cam surface. Side extensions 52 as seen in FIG. 1 are
`formed on the sides of pumping finger 48. A transverse,
`inverted “T” slot 62 is formed across the top of pump finger
`48. A base 64 mounting a transverse pinch finger 66 fits
`within slot 62, with pinch finger 66 extending through a
`transverse cavity in the pumping surface along second end
`68 of pump finger 48, as seen in FIG. 1. A spring 70 biases
`base 64 and pinch finger 66 toward the extended position.
`The pump operates in the following manner. As seen in
`FIG. 2, two lobes of cam 30 are located at the beginning and
`end of the series of pump fingers 48. At this position, pump
`fingers 48 engaging the central portion of tube 28 along the
`middle of platen 26 are relatively withdrawn and those at the
`ends are relatively extended,
`thereby creating a zone of
`occlusion. Thus, the central portion of tube 28 is filled with
`liquid and the ends are substantially occluded. As cam 30
`rotates in the direction of arrow 34, the second left pump
`finger 48 is pressed further against
`tube 28 while the
`rightmost pump finger begins to withdraw. Liquid is thus
`pushed in a zone of occlusion toward the right or outlet end
`of tube 28 and begins to exit. As cam rotation continues,
`pump fingers 48 are sequentially extended from the left and
`withdrawn at the right, forcing liquid in tube 28 toward the
`outlet end.
`
`As seen in the central region of tube 28 in FIG. 2, pinch
`fingers 66 under the forces of springs 70 are relatively
`extended. The leftmost pump finger 48 is slightly extended,
`but second end 68 of pump finger 48 has not entirely
`occluded tube 28. Pinch finger 66 is extended sufficiently
`under the force of spring 70 to occlude the tube. With a thin
`wall tube 28, pinch fingers 66 will extend further to close the
`tube. With a thick walled tube, pinch finger will only extend
`a shorter distance until the tube is closed. Thus, only enough
`force is applied through the pinch finger to close the tube.
`
`4
`
`In prior art pumps, the pumping finger extended only a
`single preset distance under the strong mechanical force of
`a cam. With those arrangements, thin tubes are not entirely
`occluded and thick walled tubes are crushed beyond closure,
`often resulting in rapid wear,
`internal wall erosion and
`spallation with the resulting injection of particles of wall
`material into the liquid stream, of great concern in many
`infusion operations. Only a short degree of extension and
`retraction of pinch fingers 66 is required to produce this
`highly advantageous result, typically from about 0.2 to 1.0
`mm.
`
`FIG. 4 shows a side elevation view of a second embodi-
`ment of pump fingers 48. Here the pump fingers 48 use a
`pinch finger in the form of a fixed transverse ridge 71 across
`the surface 68 of the pump fingers in place of the spring
`biased pinch fingers 66 of the embodiment of FIG. 3. While
`the FIG. 3 embodiment is generally preferred for lowest tube
`wear and the ability to work well tubes of slightly varying
`diameter and wall thickness, in other cases the lower cost
`version of FIG. 4 may be preferred where the tube is more
`dimensionally uniform or the motor has suflicient power and
`the tube can take greater compression.
`While certain specific relationships, materials and other
`parameters have been detailed in the above description of
`preferred embodiments, those can be varied, where suitable,
`with similar results. Other applications, variations and rami-
`fications of the present invention will occur to those skilled
`in the art upon reading the present disclosure. Those are
`intended to be included within the scope of this invention as
`defined in the appended claims.
`I claim:
`
`1. A curvilinear peristaltic pump which comprises:
`a curved, concave, platen;
`a rotatable cam spaced from said platen;
`means for rotating said cam in a first direction;
`a plurality of pump fingers, each having a first end riding
`on said cam and a second end adjacent to said platen;
`guide means for axially guiding said pump fingers in
`radial directions;
`
`'
`
`said cam configured to first sequentially move said pump
`fingers toward said platen and second sequentially
`allow said pump fingers to move away from said
`platen;
`each of said pump fingers having a pinch finger extending
`beyond said second end, transversely across second
`end;
`
`whereby a resilient tube may be interposed between said
`platen and said second pump finger ends so that as said
`pump fingers are sequentially moved toward said
`platen, liquid in said tube will be pumped in said first
`cam rotation direction and each pinch finger will
`occlude said tube when each said pump finger reaches
`a position closest to said platen.
`2. The curvilinear peristaltic pump according to claim 1
`wherein each said pinch finger comprises a slidable member
`extending through a transverse slot in each pump finger
`second end and further including means for biasing each
`said pinch finger in a direction extending outwardly of said
`transverse slot.
`
`3. The curvilinear peristaltic pump according to claim 2
`wherein each of said pump fingers has a transverse cavity
`communicating with said transverse slot,
`21 base member
`within said cavity supporting a pinch finger in said trans
`verse slot, with a compression spring between said base
`member and a wall of said cavity opposite said pinch finger.
`
`ACTA EX. 1013-005
`
`ACTA Ex. 1013-005
`
`
`
`5
`
`6
`
`5,575,631
`
`4. The curvilinear peristaltic pump according to claim 1
`wherein each said pinch finger is a transverse ridge on each
`said pump finger second end.
`5. The curvilinear peristaltic pump according to claim 1
`wherein each of said cams has at least two lobes and has a
`
`surface gradually transitioning between lobes.
`6. The curvilinear peristaltic pump according to claim 1
`wherein each pump finger carries a rotatable roller at said
`first end to engage and roll along said cam.
`7. The curvilinear peristaltic pump according to claim 1
`further including releasable latch means for attaching said
`platen to a cam support casing.
`8. The curvilinear peristaltic pump according to claim 1
`wherein said platen surface is cylindrical and said cam is
`rotatable around an axis concentric with said cylindrical
`platen surface.
`9. The curvilinear peristaltic pump according to claim 1
`wherein said cam is supported for rotation between parallel
`front and back plates.
`10. The curvilinear peristaltic pump according to claim 9
`wherein said guide means comprises cooperating pairs of
`radial grooves in said front and back plates and side exten-
`sions on each pump finger for radial sliding in a pair of said
`grooves.
`11. A curvilinear peristaltic pump which comprises:
`a curved, concave, platen;
`a rotatable multi-lobed cam spaced from said platen;
`means for rotating said cam in a first direction;
`a plurality of pump fingers, each having a first end riding
`on said cam and a second end adjacent to said platen;
`guide means for axially guiding said pump fingers in
`radial directions from a center of rotation of said cam;
`
`a resilient tube interposed between said platen and said
`pump fingers;
`said cam configured to first sequentially move said pump
`fingers toward said platen to compress said tube and
`second sequentially allow said pump fingers to be
`moved away from said platen by tube resiliency;
`each of said pump fingers sized to compress said tube as
`said cam moves said pump fingers forward said platen
`but not fully occlude said tube; and
`each of said pump fingers having a pinch finger extending
`transversely beyond said pump finger second end to
`
`frilly occlude said tube as said cam moves said pump
`fingers toward said platen.
`12. The curvilinear peristaltic pump according to claim 11
`wherein each said pinch finger comprises a slidable member
`extending through a transverse slot in each pump finger
`second end and further including means for biasing each
`said pinch finger in a direction extending outwardly of said
`transverse slot.
`
`13. The curvilinear peristaltic pump according to claim 11
`wherein each said pinch finger is a transverse ridge on each
`said pump finger second end.
`14. The curvilinear peristaltic pump according to claim 11
`wherein said cam has at least two spaced lobes and cam
`diameter smoothly changes diameter from widest at said
`lobes to narrower between said lobes.
`
`15. The curvilinear peristaltic pump according to claim 11
`wherein each pump finger carries a rotatable roller at said
`first end to engage and roll along said cam.
`16. The curvilinear peristaltic pump according to claim 11
`further including releasable latch means for attaching said
`platen to a cam support casing.
`17. The curvilinear peristaltic pump according to claim 11
`wherein said platen surface is cylindrical and said cam is.
`rotatable around an axis concentric with said cylindrical
`platen surface.
`18. The curvilinear peristaltic pump according to claim 11
`wherein said cam is supported for rotation between parallel
`front and back plates.
`19. The curvilinear peristaltic pump according to claim 18
`wherein said guide means comprises cooperating pairs of
`radial grooves in said front and back plates and further
`including side extensions on each pump finger for radial
`sliding in a pair of said grooves.
`20. The curvilinear peristaltic pump according to claim 11
`wherein each of said pump fingers comprises an elongated
`body having a transverse slot across said second end,
`extending into said pump finger and communicating with a
`cavity, said pinch finger slidably fitting within said slot and
`secured to a base in said cavity and further including a
`compression spring between said base and a wall of said
`cavity opposite said pinch finger to bias said pinch finger
`outwardly of said transverse slot.
`*
`*
`>l<
`*
`
`*
`
`ACTA EX. 1013-006
`
`ACTA Ex. 1013-006