DUAL SYRINGE FLUID PUMP

Abstract

A dual syringe fluid pump (100, 200, 300, 400) includes a motor (110, 210, 310, 410) with a rotatable shaft (112, 212, 312, 412), a first syringe (120a, 220a, 320a, 420a) with a first syringe plunger (122a, 222a, 322a, 422a) coupled to the rotatable shaft (112, 212, 312, 412), and a second syringe (120b, 220b, 320b, 420b) with a second syringe plunger (122b, 222b, 322b, 422b) coupled to the rotatable shaft (112, 212, 312, 412). The motor (110, 210, 310, 410) rotates the rotatable shaft (112, 212, 312, 412) to simultaneously move the first syringe plunger (122a, 222a, 322a, 422a) and the second syringe plunger (122b, 222b, 322b, 422b) and at least one of the syringes (120a,b, 220a,b, 320a,b, 420a,b) is adapted to convert the rotation of the rotatable shaft (112, 212, 312, 412) to a linear movement of at least one of the syringe plungers (122a,b, 222a,b, 322a,b, 422a,b).

Claims

1. A dual syringe fluid pump (100, 200, 300, 400) comprising: a motor (110, 210, 310, 410) with a rotatable shaft (112, 212, 312, 412); a first syringe (120a, 220a, 320a, 420a) with a first syringe plunger (122a, 222a, 322a, 422a) coupled to the rotatable shaft (112, 212, 312, 412); and a second syringe (120b, 220b, 320b, 420b) with a second syringe plunger (122b, 222b, 322b, 422b) coupled to the rotatable shaft (112, 212, 312, 412); wherein the motor (110, 210, 310, 410) rotates the rotatable shaft (112, 212, 312, 412) to simultaneously move the first syringe plunger (122a, 222a, 322a, 422a) and the second syringe plunger (122b, 222b, 322b, 422b); and at least one of the syringes (120a,b 220a,b 320a,b 420a,b) is adapted to convert a rotation of the rotatable shaft (112, 212, 312, 412) to a linear movement of at least one of the syringe plungers (122a,b 222a,b 322a,b 422a,b).

2. The dual syringe fluid pump (100) of claim 1 wherein at least one of the syringes (120a,b) further comprises a barrel (124a) with a center bore (124cb) having a profile that prevents rotation of the at least one of the syringe plungers (122a,b) to convert the rotation of the rotatable shaft (112) to the linear movement of the at least one of the syringe plungers (122a,b).

3. The dual syringe fluid pump (200) of claim 1 further comprising a constraint (252) and an aperture (225) in the syringe plunger (222a) wherein the constraint (252) is coupled to the motor (210) and slidably coupled to the aperture (225) to prevent a rotation of the at least one of the syringe plungers (222a,b) such that rotation of the rotatable shaft (212) is converted to the linear movement of at least one of the syringe plungers (222a,b).

4. The dual syringe fluid pump (100, 200, 300, 400) of claim 1 wherein the motor (110, 210, 310, 410) is further adapted to simultaneously move the first syringe plunger (122a, 222a, 322a, 422a) and the second syringe plunger (122b, 222b, 322b, 422b) to aspirate fluid into the first syringe (120a, 220a, 320a, 420a) and dispense fluid from the second syringe (120b, 220b, 320b, 420b).

5. The dual syringe fluid pump (100, 200, 300, 400) of claim 1 wherein at least one of the syringes (120a,b 220a,b 320a,b 420a,b) further comprises: a first valve (126ai,bi 226ai,bi 326ai,bi 426ai,bi) adapted to allow fluid to flow into the at least one of the syringes (120a,b 220a,b 320a,b 420a,b); and a second valve (126ao,bo, 226ao,bo, 326ao,bo, 426ao,bo) adapted to allow fluid to flow out of the at least one of the syringes (120a,b 220a,b 320a,b 420a,b).

6. The dual syringe fluid pump (100) of claim 1 wherein: the first syringe plunger (122a) is coupled to a first end of the rotatable shaft (112); the second syringe plunger (122b) is coupled to a second end of the rotatable shaft (112); and the rotatable shaft (112) extends through the motor (110) from the first syringe (120a) to the second syringe (120b).

7. The dual syringe fluid pump (100) of claim 1 wherein the rotatable shaft (112) rotates coaxially with the linear movement of at least one of the syringe plungers (122a,b).

8. The dual syringe fluid pump (400) of claim 1 further comprising a coupler (412b) coupled to the rotatable shaft (412) wherein the rotatable shaft (412) is adapted to rotate the coupler (412b) to move the first syringe plunger (412a) to dispense fluid from the first syringe (420a) and move the second syringe plunger (422b) to aspirate fluid into the second syringe (420b).

9. A method of forming a dual syringe fluid pump (100, 200, 300, 400), comprising: forming a motor (110, 210, 310, 410) with a rotatable shaft (112, 212, 312, 412); forming a first syringe (120a, 220a, 320a, 420a) with a first syringe plunger (122a, 222a, 322a, 422a) and coupling the first syringe plunger (122a, 222a, 322a, 422a) to the rotatable shaft (112, 212, 312, 412); forming a second syringe (120b, 220b) with a second syringe plunger (122b, 222b, 322b, 422b) and coupling the second syringe plunger (122b, 222b, 322b, 422b) to the rotatable shaft (112, 212, 312, 412); and adapting the motor (110, 210, 310, 410) to rotate the rotatable shaft (112, 212, 312, 412) to simultaneously move the first syringe plunger (122a, 222a, 322a, 422a) and the second syringe plunger (122b, 222b, 322b, 422b); and adapting at least one of the syringes (120a,b 220a,b 320a,b 420a,b) to convert a rotation of the rotatable shaft (112, 212, 312, 412) to a linear movement of at least one of the syringe plungers (122a,b 222a,b 322a,b 422a,b).

10. The method of forming the dual syringe fluid pump (100) of claim 9 wherein the forming the at least one of the syringes (120a,b) further comprises forming a barrel (124a) with a center bore (124cb) having a profile that prevents rotation of the at least one of the syringe plungers (122a,b) to convert the rotation of the rotatable shaft (112) to the linear movement of the at least one of the syringe plungers (122a,b).

11. The method of forming the dual syringe fluid pump (200) of claim 9 further comprising: forming a constraint (252); forming an aperture (225) in the syringe plunger (222a); coupling the constraint (252) to the motor (210); and slidably coupling the constraint (252) to the aperture (225) to prevent a rotation of the at least one of the syringe plungers (222a,b) such that rotation of the rotatable shaft (212) is converted to the linear movement of at least one of the syringe plungers (222a,b).

12. The method of forming the dual syringe fluid pump (100, 200, 300, 400) of claim 9 further comprising adapting the motor (110, 210, 310, 410) to simultaneously move the first syringe plunger (122a, 222a, 322a, 422a) and the second syringe plunger (122b, 222b, 322b, 422b) to aspirate fluid into the first syringe (120a, 220a, 320a, 420a) and dispense fluid from the second syringe (120b, 220b, 320b, 420b).

13. The method of forming the dual syringe fluid pump (100, 200, 300, 400) of claim 9 wherein the forming the at least one of the syringes (120a,b 220a,b 320a,b 420a,b) further comprises: forming and adapting a first valve (126ai,bi 226ai,bi 326ai,bi 426ai,bi) to allow fluid to flow into the at least one of the syringes (120a,b 220a,b 320a,b 420a,b); and forming and adapting an second valve (126ao,bo, 226ao,bo, 326ao,bo, 426ao,bo) to allow fluid to flow out of the at least one of the syringes (120a,b 220a,b 320a,b 420a,b).

14. The method of forming the dual syringe fluid pump (100, 200, 300) of claim 9 further comprising: coupling the first syringe plunger (122a, 222a, 322a) to a first end of the rotatable shaft (112, 212, 312); coupling the second syringe plunger (122b, 222b, 322b) to a second end of the rotatable shaft (112, 212, 312); and extending the rotatable shaft (112, 212, 312) through the motor (110, 210, 310) from the first syringe (120a, 220a, 320a) to the second syringe (120b, 220b, 320b).

15. The method of forming the dual syringe fluid pump (100, 200, 300, 400) of claim 9 further comprising adapting the rotatable shaft (112, 212, 312, 412) to rotate coaxially with the linear movement of at least one of the syringe plungers (122a,b 222a,b 322b, 422b).

16. The method of forming the dual syringe fluid pump (400) of claim 9 further comprising: forming and coupling a coupler (412b) to the rotatable shaft (412); and adapting the rotatable shaft (412) to rotate the coupler (412b) to move the first syringe plunger (422a) to dispense fluid from the first syringe (420a) and move the second syringe plunger (422b) to aspirate fluid into the second syringe (420b).

17. The method of forming the dual syringe fluid pump (100, 200, 300, 400) of claim 9 further comprising selecting a motor (110, 210, 310, 410) rotation to a syringe plunger (122a,b 222a,b 322a,b 422a,b) displacement ratio.

18. A method of using a dual syringe fluid pump (100, 200, 300, 400), the method comprised of: providing a dual syringe fluid pump (100, 200, 300, 400) comprised of: a motor (110, 210, 310, 410) with a rotatable shaft (112, 212, 312, 412); a first syringe (120a, 220a, 320a, 420a) with a first syringe plunger (122a, 222a, 322a, 422a) coupled to the rotatable shaft (112, 212, 312, 412); and a second syringe (120b, 220b, 320b, 420b) with a second syringe plunger (122b, 222b, 322b, 422b) coupled to the rotatable shaft (112, 212, 312, 412); providing fluid from a fluid source (370, 470) to the first syringe (120a, 220a, 320a, 420a) and the second syringe (120b, 220b, 320b, 420b); rotating the rotatable shaft (112, 212, 312, 412) with the motor (110, 210, 310, 410); and converting the rotation of the rotatable shaft (112, 212, 312, 412) to a linear movement of at least one of the syringe plungers (122a,b 222a,b 322a,b 422a,b) to dispense fluid from the first syringe (120a, 220a, 320a, 420a) while simultaneously aspirating fluid into the second syringe (120b, 220b, 320b, 420b) from the fluid source (370, 470).

19. The method of using the dual syringe fluid pump (100, 200, 300, 400) of claim 18 further comprising rotating the rotatable shaft (112, 212, 312, 412) to aspirate fluid into the first syringe (120a, 220a, 320a, 420a) from the fluid source (370, 470) while simultaneously dispensing fluid from the second syringe (120a, 220b, 320b, 420b).

20. The method of using the dual syringe fluid pump (100, 200, 300, 400) of claim 18 further comprises dispensing fluid from the first syringe (120a, 220a, 320a, 420a) and the second syringe (120b, 220b, 320b, 420b) to a fluid supply conduit (390, 490) in a substantially continuous fluid flow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The same reference number represents the same element on all drawings. It should be understood that the drawings are not necessarily to scale.

[0031] FIG. 1 shows a perspective view of a dual syringe fluid pump 100 according to an embodiment.

[0032] FIG. 2 shows a plan end view of the dual syringe fluid pump 100 taken at section 2-2 shown in FIG. 1.

[0033] FIG. 3 shows another perspective view of the dual syringe fluid pump 100.

[0034] FIGS. 4a and 4b show transparent plan views of the barrel 124.

[0035] FIGS. 5a -5c show plan and perspective views of the syringe plunger 122.

[0036] FIG. 6 shows a perspective view of a dual syringe fluid pump 200 according to another embodiment.

[0037] FIG. 7 shows a detailed perspective view of the dual syringe fluid pump 200.

[0038] FIGS. 8a and 8b show schematic views of a dual syringe fluid pump 300 according to another embodiment.

[0039] FIG. 9 shows a side plan view of a dual syringe fluid pump 400 according to an embodiment.

[0040] FIGS. 10a and 10b show schematic representations of the dual syringe fluid pump 400 according to an embodiment.

DETAILED DESCRIPTION

[0041] FIGS. 1-10b and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of a dual syringe fluid pump. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the dual syringe fluid pump. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

[0042] FIG. 1 shows a perspective view of a dual syringe fluid pump 100 according to an embodiment. As shown, the dual syringe fluid pump 100 includes a motor 110 that is coupled to a first syringe 120a and a second syringe 120b. The first syringe 120a is shown in a transparent view for clarity. The syringes 120a,b include syringe plungers 122a,b (the first syringe plunger 122a is shown). The syringes 120a,b also include barrels 124a,b that encloses the syringe plungers 122a,b. The barrels 124a,b include a center bore 124cb. Inlet 126ai,bi and outlet valves 126ao,bo are coupled to the barrels 124a,b. The first inlet valve 126ai is not shown in FIG. 1 for clarity. The outlet valves 126ao,bo allow fluid in the dual syringe fluid pump 100 to be dispensed by the syringes 120a,b. The inlet valves 126ai,bi allow fluids to be aspirated into the syringes 120a,b as will be described in more detail in the following.

[0043] FIG. 2 shows a plan end view of the dual syringe fluid pump 100 taken at section 2-2 shown in FIG. 1. As can be seen, the syringe plungers 122a,b have profiles that interface with profiles in the barrels 124a,b. The interfaced profile is shown as oval shaped with flat sides. As will be described in more detail in the following with reference to FIG. 4a-5c, the interfaced profiles prevent the rotation of the syringe plungers 122a,b. Preventing the plungers 122a,b from rotating can convert the motor 110 rotation to a linear displacement of the syringe plungers 122a,b. The motor 110 can also be adapted to simultaneously move the syringe plungers 122a,b as will be described in more detail in the following.

[0044] FIG. 3 shows another perspective view of the dual syringe fluid pump 100. The first syringe 120a is shown with an exploded perspective view for clarity. The motor 110 includes a rotatable shaft 112. The rotatable shaft 112 is coupled to the syringe plungers 122a,b. The first syringe plunger 122a has two O-rings 123. Between the motor 110 and the first syringe 120a are pins 140. The pins 140 align and couple the motor 110 with the collars 130a,b. A set screw 132 is employed to couple the collars 130a,b with the syringe barrels 124a,b although any suitable fastening means can be employed. The collars 130a,b also couple the syringes 120a,b to the motor 110.The rotatable shaft 112 is shown as a through axis shaft that extends through the center of the motor 110. However, in alternative embodiments, more than one shaft can be employed (e.g., with a coupling or the like). The shaft 112 can also be located somewhere other than the center of the motor 110. As shown, the syringe plungers 122a,b are coupled to a first and second distal ends of the rotatable shaft 112.

[0045] The motor 110 is adapted to rotate the rotatable shaft 112 to simultaneously move the syringe plungers 122a,b. The motor 110 can therefore simultaneously dispense fluid from the first syringe 120a and aspirate fluid into the second syringe 120b. The rotation can also cause a torque on the plunger 122a that, if not prevented, could cause the plunger 122a to rotate. The following discusses how the plunger 122a,b is prevented from rotating.

[0046] FIGS. 4a and 4b show transparent plan views of the barrel 124. FIG. 4a shows a side plan view of the barrel 124 and FIG. 4b shows an end plan view of the barrel 124. The barrel 124 is shown as having a slot 124ss that is adapted to receive the set screw 132. Also shown are the center bore 124cb, an inlet bore 124ib, and an outlet bore 124ob. The center bore 124cb is coupled to the inlet bore 124ib and the outlet bore 124ob via an inlet tap 124it and an outlet tap 124ot. As can be seen, the center bore 124cb has a shaped profile. This shaped profile can interface with the syringe plunger 122.

[0047] FIGS. 5a -5c show plan and perspective views of the syringe plunger 122. The syringe plunger 122 includes a face rib 122fr, a center rib 122cr, and a rear rib 122rr. The syringe plunger 122 also includes two O-ring slots 122s1,s2. Although two O-ring slots 122s1,s2 are shown, more or fewer O-ring slots may be employed in alternative embodiments. The O-ring slots 122s1,s2 are adapted to receive and hold the O-rings 123 described with reference to FIG. 3. As can be seen in FIGS. 5 and 5c, the plunger 122a has a shaped profile.

[0048] Referring to FIGS. 4a-5c as well as FIG. 2, the center bore 124cb profile can interface with the syringe plunger 122's profile. The interfaced profiles are shown as oval shaped with flat sides although other appropriately shaped profiles can be employed. The interfaced profiles provide a fluid seal that can prevent leakage of fluid past the O-rings 123 shown in FIG. 3. This allows the fluid dispensed from and aspirated into the syringes 120 to be precise, accurate, and repeatable. For example, if the fluid leakage past the O-rings 123 is prevented, the volume of fluid dispensed may not vary between each dispensing due to leakage. The volume of the fluid dispensed can therefore be more precise.

[0049] The interfaced profiles also prevent the plunger 122a,b from rotating when the motor 110 rotates the rotatable shaft 112. For example, the rotatable shaft 112 can rotate to move the plunger 112a away from the motor 110. Friction between the rotatable shaft 112 and the plunger 112a can therefore apply a torque to the plunger 112a. The interfaced profiles apply reactive forces to the plunger 112a that counter the torque. The reactive forces prevent the plunger 112a from rotating. Similar results can be obtained from other profiles shapes such as square shaped profiles with rounded corners or the like. As an alternative to the shaped interfaced profiles, other embodiments can employ constraints to prevent the plunger from rotating, which are described in the following with reference to FIGS. 6 and 7.

[0050] FIG. 6 shows a perspective view of a dual syringe fluid pump 200 according to another embodiment. The dual syringe fluid pump 200 is shown with an exploded view of the first syringe 220a. The dual syringe fluid pump 200, similar to the dual syringe fluid pump 100, includes a motor 210 that is coupled to a first syringe 220a and a second syringe 220b. A collar 250 is between the motor 210 and the first syringe 220a. The syringes 220a,b includes syringe plungers 222a,b slidably disposed inside barrels 224a,b (only the first syringe plunger 222a is shown). In contrast to the syringe plunger 112a shown in FIGS. 1-5c, the syringe plunger 222a has a circular shape. O-rings 223 are disposed around the syringe plunger 222a. The barrel 224a has a center bore 224cb, an outlet bore 226ao, an inlet bore 226ai. The center bore 224cb is coupled to the inlet valve 226ai and the outlet valve 226ao. The syringe 220 also includes a nut 225 that is coupled to syringe plunger 222a. The barrel 224a also includes a nut bore 227. The nut 225 is adapted to fit into the nut bore 227. The nut 225 also has apertures 225 that are slidably coupled to constraints 252. Although two apertures 225 and constraints 252 are shown, more or fewer may be employed in alternative embodiments.

[0051] FIG. 7 shows a detailed transparent perspective view of the dual syringe fluid pump 200. For clarity, the motor 210 and the first syringe 220a are shown in a transparent assembled view without the second syringe 220b. The syringe plunger 222a is slidably disposed in the center bore 224cb. The center bore 124cb is coupled to the inlet bore 124ib and the outlet bore 124ob via an inlet tap 124it and an outlet tap 124ot. The constraints 252 are coupled to the barrel 224a. The nut 225 is slidably disposed inside the nut bore 227.

[0052] The nut 225 can move linearly along the length of the constraints 252. The constraints 252 prevent the rotation of the syringe plunger 222a. For example, when the motor 210 rotates the rotatable shaft 212, the constraints 252 oppose a rotational torque on the syringe plunger 222a. This can prevent the rotation of the syringe plunger 222a thereby converting the rotation of the rotatable shaft 212 to a linear movement and displacement of the syringe plunger 222a within the center bore 224cb. Accordingly, the syringe plunger 222a can have a profile (e.g., circular) that does not prevent the rotation of the syringe plunger 222a.

[0053] With reference to FIGS. 1-7, the motor 110, 210 is a direct drive motor although any suitable motor, such as a stepper motor, can be employed. In the embodiment shown, the motor 110, 210 can also include an encoder that detects the rotation position of the motor 110, 210. The motor 110, 210 is adapted to simultaneously move the syringe plungers 122a,b, 222a,b in the barrels 124a,b 224a,b. The motor 110, 210 is disposed between and coupled to the syringes 120a,b 220a,b. However, in alternative embodiments, such as those shown in FIGS. 9-10b, the motor can be coupled to syringes in different configurations or locations. The motor 110, 210 is adapted to receive a command from a controller (see FIGS. 8a-8b) that instructs the motor 110, 210 to rotate the rotatable shaft 112, 212 a desired amount. The desired amount can be in units of radians, steps, or the like. The encoder in the motor 110, 210 can also send information to the controller. As will be explained in more detail in the following, the desired rotation can correspond with the amount of fluid that is dispensed from and aspirated into the syringes 120a,b 220a,b.

[0054] The motor 110, 210 is adapted to rotate the rotatable shaft 112, 212 to simultaneously move the syringe plungers 122a,b 222a,b. The motor 110, 210 can therefore simultaneously dispense fluid from the first syringe 120a, 220a and aspirate fluid into the second syringe 120b, 220b. For example, in the embodiment shown, the motor 110, 210 rotates the rotatable shaft 112, 212 which moves the first syringe plunger 122a, 222a away from the motor 110, 210. The rotation also moves the second syringe plunger 122b, 222b towards the motor 110, 210. In this exemplary movement, fluid is dispensed from the first syringe 120a, 220a via the first outlet valve 126ao, 226ao and aspirated into the second syringe 120b, 220b via the second inlet valve 126bi, 226bi. Rotating the shaft 112, 212 in the opposite direction causes fluid to be aspirated into the first syringe 120a, 220a and fluid to be dispensed from the second syringe 120b, 220b.

[0055] The rotatable shaft 112, 212 is a lead screw adapted to linearly move the syringe plungers 122a,b 222a,b according to a rotation-to-displacement ratio. That is, each unit of rotation of the rotatable shaft 112, 212 corresponds to a displacement of the plungers 122a,b 222a,b. Although the rotatable shaft 112, 212 is a lead screw shaft with threads, any appropriate means of converting the shaft 112, 212 rotation to a linear movement and displacement of the syringe plungers 122, 222 can be employed. In the embodiment shown, the rotatable shaft 112, 212 is comprised of screw threads with a selected rotation-to-displacement ratio, which can be expressed as number of threads per unit length. Therefore, when the motor 110, 210 receives a command from a controller (see FIGS. 8a-8b) to rotate a desired amount, the rotatable shaft 112, 212 is adapted to move the syringe plungers 122, 222 a desired displacement length. In the embodiment shown, the rotatable shaft 112, 212 moves linearly along the center axis of the motor 110, 210 to move the plungers 122, 222.

[0056] Converting the shaft 112, 212 rotation to a linear movement and displacement of the syringe plungers 122, 222 allows the motor 110, 210 to dispense from and aspirate fluid into the syringes 120, 220. The motor 110, 210 can also dispense fluid in a substantially continuous manner, as will be described in the following with reference to FIGS. 8a-8b.

[0057] FIGS. 8a and 8b show a schematic view of a dual syringe fluid pump 300 according to another embodiment. The dual syringe fluid pump 300 is a schematic representation of the dual syringe fluid pumps 100, 200 described with reference to FIGS. 1 to 7. For example, the syringes 320a,b represent the syringes 120, 220 described with reference to FIGS. 1 to 7. Accordingly, description of features shown in FIGS. 8a-8b can correspond to features described with reference to FIGS. 1-7. However, the dual syringe fluid pump 300 can also be a schematic representation of other embodiments.

[0058] As shown, the dual syringe fluid pump 300 includes a motor 310 that is coupled to a first syringe 320a and a second syringe 320b. The motor 310 is adapted to dispense fluid from and aspirate fluid into the syringes 320a,b. Also shown is a controller 360 that is electrically coupled to the motor 310 and the syringes 320 via signal lines 362a,b. The signal lines 362a,b are adapted to carry signals between the controller 360 and syringes 320a,b which can have sensors 320as,bs. A fluid source 370 and a fluid supply conduit 390 is also shown. The fluid source 360 is fluidly coupled to the syringes 320a,b. The fluid supply conduit 390 is a conduit that can be coupled to equipment that uses fluid dispensed by the fluid pump 300.

[0059] Arrows indicating movement are also shown in FIGS. 8a and 8b. The direction of the plunger 322a,b displacement is represented by an arrow in the motor 310. The direction of the fluid flow dispensed from and aspirated into the syringes 320a,b is shown by arrows proximate the valves 326. For example, the arrow proximate the first syringe outlet valve 326ao indicates that the fluid is being dispensed from the first syringe 320a. The arrow proximate the second syringe inlet valve 326bi shown in FIG. 8a indicates that fluid is being aspirated into the second syringe 320b. The arrow in the motor 310 in FIG. 8a indicates that the syringe plunger 322a in the first syringe 320a is moving away from the motor 310. The syringe plunger 322b is moving towards the motor 310.

[0060] The displacement direction of the syringe plungers 322a,b shown in FIG. 8a dispenses fluid from the first syringe 320a via the outlet valve 326ao. This displacement also aspirates fluid into the second syringe 320b via the inlet valve 326bi. The first syringe inlet valve 326ai and the second syringe outlet valve 326bo are closed due to the pressure in the syringes 320a,b. A relatively low pressure in the second syringe 320b prevents the second outlet valve 320bo from opening. A relatively high pressure in the first syringe 320a prevents the first inlet valve from opening. In FIG. 8b, the displacement direction of the syringe plungers 322a,b shown as moving in a direction opposite the direction shown in FIG. 8a.

[0061] The dual syringe fluid pumps 100-300 described with reference to FIGS. 1-8b have rotatable shafts 112-312 in a through axis configuration. The through axis configuration allows the motor 110-310 to simultaneously move the first syringe plunger 120a-320a and the second syringe plunger 120b-320b. However, other embodiments of the dual syringe fluid pump can simultaneously move the syringe plungers 122a,b-322a,b without using the through axis configuration, as will be described in the following with reference to FIGS. 9-10b.

[0062] FIG. 9 shows a side plan view of a dual syringe fluid pump 400 according to an embodiment. As shown, the motor 410 is disposed on one side of the dual syringe fluid pump 400. The syringes 420a,b are arranged in a parallel configuration. The syringes 420a,b have syringe plungers 422a,b. The dual syringe fluid pump 400 can have inlet and outlet valves 426. In the embodiment shown, the first syringe 420a has an inlet valve 426ai and an outlet valve 426ao. The second syringe 420b has an inlet valve 426bi and an outlet valve 426bi. Similar to the embodiments described in the foregoing, the motor 410 has a rotatable shaft 412. The rotatable shaft 412 is shown with an encoder 412a. The rotatable shaft 412 is coupled to the syringe plungers 422a,b via a coupler 412b. The coupler 412b is a worm gear coupler although other couplers can be employed in alternative embodiments. The syringe plungers 422a,b have grooved portions 422at,bt (e.g., cam locks or the like) that are coupled to the coupler 412b.

[0063] Due to the parallel configuration of the syringes 420a,b the plungers 422a,b in the syringes 420a,b have parallel stroke axes. However, in alternative embodiments, the stroke axes can be oriented in different directions. In the embodiment shown, the syringe plungers 422a,b move away from the motor 410 to dispense fluids from the first syringe 420a. The syringe plungers 422a,b move towards the motor 410 to aspirate fluid into the plungers 420a,b. Accordingly, the motor 410 can move the syringe plungers 422a,b to dispense fluid from and aspirate fluid into the syringes 420a,b.

[0064] The motor 410 rotates the coupler 412b to move the syringe plungers 422a,b in opposite directions. The rotating coupler 412b is engaged with the grooved portions 412at,bt. In the embodiment shown, the grooved portions 412at,bt have grooves with opposing orientations. For example, the first grooved portion 412at can have left hand twisted grooves. The second thread portion 412bt can have right hand twisted grooves. When the coupler 412b rotates, the opposing orientations of the grooves causes the plungers 422a,b to move in opposite directions. For example, the first plunger 422a can move away from the motor 410 while the second plunger 422b simultaneously moves toward the motor 410. To reverse the directions of the plungers 422a,b the motor 410 reverses the rotation of the rotatable shaft 412. The motor 410 can therefore rotate the rotatable shaft 412 to simultaneously move the syringe plungers 422a,b.

[0065] The rotation of the rotatable shaft 412 can be detected by the encoder 412a. In the embodiment shown, the encoder 412a is a position sensor that detects the rotation position of the rotatable shaft 412. The encoder 412 generates a signal (e.g., electrical) that is communicated to a controller (described with reference to FIGS. 10a-10b). Using the signal provided by the encoder 412, the controller can precisely and accurately dispense fluid from the dual syringe fluid pump 410, as will be discussed in more detail in the following.

[0066] FIGS. 10a and 10b show schematic representations of the dual syringe fluid pump 400 according to an embodiment. The dual syringe fluid pump 400 includes the motor 410 which is coupled to the syringes 420a,b. Although not shown for clarity, the syringe plungers 422a,b are in the syringes 420a,b. The rotation direction of the rotatable shaft 412 is indicated by an arrow in shown in the motor 410. The arrow in FIG. 10a indicates indicates that the rotatable shaft 412 is rotating in a direction with an axis oriented, using the right hand rule, towards the syringe plungers 420a,b. The arrow in FIG. 10b indicates the rotatable shaft 412 is rotating in an opposite direction.

[0067] The direction of the fluid flow dispensed from and aspirated into the syringes 420a,b is shown by arrows proximate the valves 426. For example, the arrow proximate the first syringe outlet valve 426ao indicates that the fluid is dispensed from the first syringe 420a. The arrow proximate the second syringe inlet valve 426bi shown in FIG. 10a indicates that fluid is being aspirated into the second syringe 420b. FIG. 10a shows that the syringe plungers 122a,b 222a,b dispenses fluid from the first syringe 420a via the outlet valve 426ao and aspirates fluid into the second syringe 420b via the inlet valve 426bi. The first syringe inlet valve 426ai and the second syringe outlet valve 426bo are shown as closed due to the fluid pressure in the syringes 420a,b. In FIG. 10b, the syringe plungers 422a,b are shown as moving in directions opposite the directions shown in FIG. 10a.

[0068] In operation, the dual syringe fluid pump 100-400 dispenses fluid from the first syringe 120a-420a and the second syringe 120b-420b. The fluid can be supplied to the syringes 120a,b-420a,b by the fluid source 370, 470 described with reference to FIGS. 8a-10b. The motor 110-410 can rotate the rotatable shaft 112-412 to dispense fluid from the first syringe 120a-420a while simultaneously aspirating fluid from the fluid source 370, 470 into the second syringe 120-420b. The motor 110-410 can also rotate the rotatable shaft 112-412 to aspirate fluid into the first syringe 120a-420a from the fluid source 370, 470 while simultaneously dispensing fluid from the second syringe 120b-420b.

[0069] The fluid, being dispensed from one of the syringes 120a,b-420a,b while the other is aspirating fluid, flows from the fluid supply port 390, 490 in a substantially continuous manner. For example, even though there are two syringes 120a,b dispensing fluid in an alternating manner, one of the syringe plungers 122a,b-422a,b is dispensing fluid to the fluid supply conduit 390, 490. The syringes 120-420 also do not dispense fluid at the same time. For example, the syringe plungers 122a,b-322a,b described with reference to FIGS. 1-9 are coupled to distal ends of the shaft 112, 212. The motor 110-310 can therefore move the syringe plungers 122a,b-322a,b in opposite directions. Similarly, the motor 410 described with reference to FIGS. 9-10b is coupled to the syringe plungers 422a,b via a coupler 412b that can simultaneously move the syringe plungers 422a,b in opposite directions. Since the first syringe plunger 122a-422a and the second syringe plunger 122b-422b move in opposite directions, the fluid is not dispensed from the first syringe 120a-420a at the same time as the second syringe 120b-420b.

[0070] The embodiments described above provide a dual syringe fluid pump 100-400. As explained above the dual syringe fluid pump 100-400 can simultaneously move syringe plungers 122a,b-422a,b to dispense fluids from a first syringe 120a-420a and aspirate fluid into a second syringe 120b-420b. This simultaneous movement reduces the complexity of the dual syringe fluid pump 100-400 over prior art dual syringe fluid pumps. In addition, having two syringes 120a,b-420a,b allows for the fluids to be dispensed precisely and accurately as well as continuously. For example, the displacement length of the syringe plungers 120a,b-420a,b can, for example, be controlled by sensors 320as,bs that detect when the syringe plungers 120a,b-420a,b have moved to their fully dispensed or aspirated positions. This allows the displacement length of the syringe plungers 122a,b-422a,b to be controlled so desired amounts of fluids can be dispensed.

[0071] Since the dual syringe fluid pump 100-400 is less complex than prior art fluid pump designs, the precision and accuracy of the amount of fluid dispensed by the dual syringe fluid pump 100-400 is repeatable over a large number of cycles. The design of the dual syringe fluid pump 100 described with reference to FIGS. 1-5c is even less complex by providing an interfaced profile that is adapted to prevent the rotation of the syringe plunger 122a,b. For some applications, the interfaced profile can eliminate the need for additional or alternative constraints 252 that also limit the rotation of the syringe plungers 222a,b described with reference to FIGS. 6-7. Depending on the application, the constraints 252 or the shaped profile plungers 122a,b may be preferred.

[0072] The dual syringe fluid pump 100-400 is also compact. For example, the dual syringe fluid pump 100-300 with the through axis configuration can have a narrow profile. The through axis configuration can also have a profile more narrow than the dual syringe fluid pump 400 having the side motor 410 configuration. However, the dual syringe fluid pump 400, with the motor 410 on one side, can fit into a cube shaped envelope. The preferred configuration can depend on the available envelope in which the dual syringe fluid pump 100-400 is employed.

[0073] The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the present description. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the present description. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present description.

[0074] Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other dual syringe fluid pumps, and not just to the embodiments described above and shown in the accompanying figures. Accordingly, the scope of the embodiments described above should be determined from the following claims.