Syringe pump

Description

[0001] The present disclosure relates to a syringe pump according to the preamble of patent claim 1, in particular a syringe pump having a syringe holder for holding a syringe cylinder of an inserted syringe, a drive unit for axially displacing a piston rod of the syringe, and a braking element movable transversely to the longitudinal direction of the syringe by means of a braking actuator from a release position to a braking position and back, which braking element contacts the piston rod in the braking position. Background of the Revelation

[0002] With syringe pumps of the aforementioned type, the problem arises that the known brake actuators have a relatively long reaction time. After a brake signal is transmitted to the brake actuator, it takes exactly this reaction time for the brake element to contact the piston rod and thus fix it in the axial direction. This reaction time therefore negatively impacts the dosing accuracy of the syringe pump.

[0003] When the syringe pump is started up, the drive unit moves onto the piston rod. The piston rod is held in place by the brake element, preventing axial displacement of the piston rod. This prevents accidental discharge of fluid when the drive unit moves onto the piston rod during start-up. State of the art

[0004] Such a syringe pump is known from EP 1 329 232 B1. The brake actuator disclosed therein comprises a motor arranged on a carriage. This motor drives a gear with helical teeth mounted on the carriage via a worm gear. The gear is provided with a threaded bore that engages with the thread of a spindle rod. By rotating the gear, the spindle rod, which is secured against co-rotation, is axially displaced. The spindle rod thus forms a linear drive, on which the brake element itself is also arranged. The brake actuator thus has a complex mechanism, which is why a relatively long response time is to be expected. Furthermore, temperature differences or wear can have a negative impact on the response time, so that the response time is not only relatively long, but also its exact length is unknown, which further negatively impacts dosing accuracy. Brief description of the revelation

[0005] The present disclosure is based on the object of providing a syringe pump that reduces or eliminates the problems of the prior art. In particular, the dosing accuracy of the syringe pump is to be improved.

[0006] This object is achieved by a syringe pump according to claim 1. Further advantageous embodiments are the subject of the subclaims.

[0007] More precisely, the problem is solved by the brake actuator having or being a piezo element for moving the brake element. Such a piezo element has a particularly short response time, which in turn improves the dosing accuracy of the syringe pump. After a braking signal is transmitted to the piezo element, the brake element is quickly moved into its braking position by the piezo element as the brake actuator, so that the piston rod is then fixed in its axial position and no further fluid can be pumped out of the syringe barrel by the piston rod.

[0008] In a preferred embodiment of the syringe pump, the piezo element comprises a stack of several piezo plates connected electrically in parallel.

[0009] By designing the piezo element as a stack with several piezo plates connected electrically in parallel, the change in length of the piezo element can be increased, which the piezo element can perform when an electrical voltage is applied to the piezo element.

[0010] Preferably, the braking element comprises a knife, a blade or a pin for axially locking the piston rod in the braking position of the braking element.

[0011] Using the knife / blade or the pin, the risk of the piston rod slipping on the brake element is minimized.

[0012] Advantageously, the piezo element is connected to a control and / or regulation device preferably arranged in the syringe holder for its control and / or regulation.

[0013] The control and / or regulating device enables dosing of the fluid pumped from the syringe barrel by the syringe pump. For this purpose, the control and / or regulating device is preferably also connected to the drive unit for control purposes. A drive signal can be transmitted to the drive unit and a brake signal to the brake actuator by means of the control and / or regulating device. Furthermore, the control and / or regulating device could be data-linked to an input unit, so that the amount of fluid to be dosed by the syringe can be transmitted to the control and / or regulating device of the syringe pump by means of such an input unit.

[0014] It is further preferred to determine the size of the syringe with the aid of the pressure transmitted from the braking element to the piezo element, the resulting pressure measurement signal transmitted from the piezo element to the control and / or regulating device and by means of software that can be executed by means of the control and / or regulating device.

[0015] This determination of the syringe size represents a way to avoid dosing errors due to the assumption of an incorrect syringe size.

[0016] In a further embodiment of the syringe pump, the syringe barrel can be supported on one side by means of the syringe holder over a circumferential area of ​​less than 180° of the syringe barrel in the radial direction. The syringe holder is arranged on a side of the syringe barrel opposite the braking element, and a braking piston rod connects the syringe holder and the braking element.

[0017] This ensures that the syringe is securely held in position even when a braking force is applied by the braking element to the tip's piston rod. Furthermore, the tip can be quickly and safely inserted into the desired position relative to the syringe pump. The braking piston rod is designed to be rigid or at least partially movable.

[0018] The brake actuator is advantageously located on the same side of the syringe barrel as the brake element. The brake actuator preferably contacts the brake element. This further shortens the reaction time. Alternatively, the use of a gear (power transmission train) between the brake actuator and the brake element is conceivable.

[0019] Further preferably, the brake actuator is connected to the control and / or regulating device by means of a cable running through the brake piston rod.

[0020] Control and / or regulation signals can be transmitted via the cable. It is also conceivable that the brake actuator could be supplied with power via the cable. Such a power supply can also be implemented, for example, with the control and / or regulation device.

[0021] According to a further, alternative embodiment of the syringe pump, the brake actuator is arranged on the same side of the syringe barrel as the syringe holder. The brake actuator then allows the brake piston rod to be moved transversely to the longitudinal direction of the syringe to move the brake element from the release position to the braking position and back.

[0022] This allows the tip pump area associated with the braking element, which is located on the side of the syringe barrel opposite the syringe holder, to be made particularly small. Furthermore, electrical assembly of the syringe pump can be simplified because all components requiring electrical power can be arranged particularly close to one another.

[0023] In summary, such a syringe pump is suitable for a wide range of applications, such as dosing medication in liquid form by means of syringes, for example, into the bloodstream or other parts of the body of people. Short description of the characters

[0024] In the following, preferred embodiments are presented in more detail with reference to the attached figures. Fig. 1 shows a schematic representation of a first embodiment of the syringe pump in a side view. Fig. 2shows a schematic representation of a section of the first embodiment of the syringe pump in a three-dimensional view. Fig. 3 shows a schematic representation of a second embodiment of the syringe pump in a side view. Fig. 4 shows a schematic representation of a section of the second embodiment of the syringe pump in a three-dimensional view. Description of preferred embodiments

[0025] The syringe pump 1 has according to Fig.1 and Fig.3 among other things a syringe holder 2 for holding a syringe cylinder 3.1 of an inserted syringe 3, a drive unit 4 for the axial displacement of a piston rod 3.2 of the syringe 3, and a braking element 6 which can be moved transversely to the longitudinal direction L of the syringe 3 by means of a braking actuator 5 from a release position p F into a braking position p B and back, which braking element contacts the piston rod 3.2 in the braking position p B.

[0026] Fig.1 and Fig.3 show the braking element 6 in the release position p F . In the three-dimensional view of the first embodiment of the syringe pump 1 from Fig. 2 The braking element 6 is shown in the braking position p B with contact to the piston rod 3.2. In Fig.4 the interior of the tip holder 2 of the second embodiment of the syringe pump 1 is shown, with the syringe 3 being shown in the figure for the sake of clarity. Fig.4 not shown. The same reference numerals are used for the same components in all figures.

[0027] The brake actuator 5 has a piezo element 7 for moving the brake element 6.

[0028] To actuate the brake actuator 5, a voltage is applied to the piezo element 7. For this purpose, two wires are connected to the piezo element 7, as symbolized by corresponding lines in the figures. Depending on the voltage polarity, the piezo element 7 expands or contracts in its axial direction. The axial direction of the piezo element 7 refers to the direction in which the change in length of the piezo element 7, due to the coupling of the piezo element 7 to the brake element 6, leads to the movement of the brake element 6.

[0029] The piezo element 7 has a stack of several piezo plates connected electrically in parallel in order to achieve the required change in length at reasonable voltage values.

[0030] The braking element 6 has a knife 8 or a pin for axially locking the piston rod 3.2 in the braking position p B of the braking element 6.

[0031] The piezo element 7 is connected to a control and / or regulation device 9, preferably arranged in the syringe holder 2, for its control and / or regulation. The control and / or regulation device 9 is according to Fig.4 arranged on a circuit board and can be supplied with power, for example, by a battery that can also be arranged in the syringe holder 2. Alternatively, the syringe pump 1 could be connected to an external power supply via a power cable.

[0032] The size of the syringe 3 can be determined using the pressure transmitted from the braking element 6 to the piezo element 7, the resulting pressure measurement signal transmitted from the piezo element 7 to the control and / or regulating device 9, and software executable by the control and / or regulating device 9. In particular, the diameter of the tip cylinder 3.1 can be determined. To determine the size of the tip 3, the control and / or regulating device 9 preferably contains a table in which various pressure measurement values ​​are assigned to different syringe sizes. Such a table is determined, for example, before use of the tip pump 1 using this or an identical syringe pump and corresponding syringes 3, and is stored in the control and / or regulating device 9.Alternatively, a corresponding functional, modeled dependency of syringe size to pressure measurement signal could also be stored in the control and / or regulation device 9.

[0033] The syringe cylinder 3.1 can be supported on one side, over a circumferential area of ​​less than 180° of the syringe cylinder 3.1 in the radial direction r, by means of the syringe holder 2. The syringe holder 2 is arranged on a side of the syringe cylinder 3.1 opposite the braking element 6. A braking piston rod 10 connects the syringe holder 2 and the braking element 6 to one another.

[0034] The brake actuator 5 is made according to the first embodiment of the syringe pump 1 from Fig.1 and Fig.2arranged on the same side of the syringe barrel 3.1 as the braking element 6. Preferably, the braking actuator 5 contacts the braking element 6. For example, the knife 8 or the pin is arranged directly on the piezo element 7 and connected to the piezo element 7. The axial direction of the piezo element 7 then runs parallel to the direction of movement of the braking element 6. Preferably, the direction of movement of the braking element 6 and the axial direction of the piston rod 3.2 run substantially perpendicular to one another.

[0035] The brake actuator 5 is then according to Fig.1 and Fig.2 connected to the control and / or regulating device 9 by means of a cable 11 running through the brake piston rod 10.

[0036] The cable 11 is preferably two-wire. The polarity of the voltage applied to the piezo element 7 is Fig.1 and Fig.2preferably selected such that the piezo element 7 expands when voltage is applied and the braking element 6 is then moved from its release position p F into the braking position p B or is subsequently held in the braking position p B. Alternatively, it is also conceivable for the polarity to be selected such that the braking element 6 is in the braking position p B when no voltage is applied to the piezo element 7. When a voltage is applied to the piezo element 7, the braking element 6 is then moved from the braking position p B into the release position p F or is subsequently held in the release position p F by axial contraction of the piezo element 7. The polarity is preferably selected such that during operation of the syringe pump 1, the piezo element 7 does not have to be supplied with current for a longer period than it needs to be supplied with current.

[0037] The brake actuator 5 is made according to the second embodiment of the syringe pump from Fig.3 and Fig.4 arranged on the same side of the syringe cylinder 3.1 as the syringe holder 2. By means of the brake actuator 5, the brake piston rod 10 is movable transversely to the longitudinal direction L of the syringe 3 in order to move the braking element 6 from the release position p F to the braking position p B and back.

[0038] In particular, the brake piston rod 10 then has a rigid wooden cylindrical shell and an axially movable, preferably cylindrical core, wherein the core is then connected to the brake actuator 5, in particular to the piezo element 7.

[0039] The polarity of the voltage applied to the piezo element 7 is according to Fig.3 and Fig.4preferably selected such that the piezo element 7 contracts when voltage is applied and the braking element 6 then moves from its release position p F into the braking position p B or is subsequently held in the braking position p B. Alternatively, it is also conceivable for the polarity to be selected such that the braking element 6 is in the braking position p B when no voltage is applied to the piezo element 7. When a voltage is applied to the piezo element 7, the braking element 6 is then guided from the braking position p B into the release position p F or is subsequently held in the release position p F by the axial expansion of the piezo element 7. The polarity is also preferably selected in this second embodiment of the syringe pump 1 such that during operation of the syringe pump 1 the piezo element 7 does not have to be supplied with current for a longer period than it needs to be supplied with current.

[0040] The syringe pump 1 preferably has a clamping mechanism 12, by means of which the syringe cylinder 3.1 can be secured after the syringe 3 has been inserted into the syringe pump 1. In particular, a syringe wing formed on the syringe cylinder 3.1 can be clamped by means of the clamping mechanism 12. To remove the syringe 3 from the syringe pump 1, the clamping mechanism 12 is first released. List of reference symbols

[0041] 1Syringe pump 2Syringe holder 3Syringe 3.1Syringe cylinder of syringe 3 3.2Piston rod of syringe 3 4Drive unit 5Brake actuator 6Brake element 7Piezo element 8Blade 9Control and / or regulating device 10Brake piston rod 11Cable 12Clamping mechanism L Longitudinal direction of the syringe 3 r Radial direction of the syringe 3 p F Release position of the braking element 6 p B Braking position of the braking element 6

Claims

1. A syringe pump (1) with a syringe holder (2) for holding a syringe cylinder (3.1) of an inserted syringe (3), a drive unit (4) for axial displacement of a piston rod (3.2) of the syringe (3), and a brake element (6) which can be moved transversely to the longitudinal direction (L) of the syringe (3) via a brake actuator (5) from a release position (pF ) into a brake position (pB ) and back and which contacts the piston rod (3.2) in the brake position (pB ), characterized in that the brake actuator (5) has a piezo element (7) for moving the brake element (6).

2. The syringe pump (1) according to claim 1, characterized in that the piezo element (7) comprises a stack of several piezo plates electrically connected in parallel.

3. The syringe pump (1) according to one of claims 1 or 2, characterized in that the brake element (6) has a knife (8) or a pin for axial locking of the piston rod (3.2) in the brake position (pB ) of the brake element (6).

4. The syringe pump (1) according to one of the preceding claims, characterized in that the piezo element (7) is connected to a control device and / or regulation device (9) preferably arranged in the syringe holder (2) for its control and / or regulation.

5. The syringe pump (1) according to claim 4, characterized in that a size of the syringe (3) is determinable by means of the pressure transmitted from the brake element (6) to the piezo element (7), by the resulting pressure measurement signal transmitted from the piezo element (7) to the control device and / or regulation device (9), and by software executable via the control device and / or regulation device (9).

6. The syringe pump (1) according to one of the preceding claims, characterized in that the syringe cylinder (3.1) can be supported on one side over a circumferential region of less than 180° of the syringe cylinder (3.1) in the radial direction (r), via the syringe holder (2), which is arranged on a side of the syringe cylinder (3.1) opposite the brake element (6), and a brake piston rod (10) connects the syringe holder (2) and the brake element (6) to one another.

7. The syringe pump (1) according to claim 6, characterized in that the brake actuator (5) is arranged on the same side of the syringe cylinder (3.1) as the brake element (6) and preferably contacts the brake element (6).

8. The syringe pump (1) according to claim 7, characterized in that the brake actuator (5) is connected to the control device and / or regulation device (9) via a cable (11) running through the brake piston rod (10).

9. The syringe pump (1) according to claim 6, characterized in that the brake actuator (5) is arranged on the same side of the syringe cylinder (3.1) as the syringe holder (2), and the brake piston rod (10) is movable transversely to the longitudinal direction (L) of the syringe (3) via the brake actuator (5) in order to move the brake element (6) from the release position (pF ) to the brake position (pB ) and back.