WO2019016279A1

WO2019016279A1 - Volumetric pump

Info

Publication number: WO2019016279A1
Application number: PCT/EP2018/069531
Authority: WO
Inventors: Matthias SCHWALM; Hans-Josef Gerlach
Original assignee: B. Braun Melsungen Ag
Priority date: 2017-07-20
Filing date: 2018-07-18
Publication date: 2019-01-24
Also published as: CN110997038B; RU2769063C2; DE102017116398A1; EP3655062A1; RU2020107430A; CN110997038A; RU2020107430A3

Abstract

The invention relates to a volumetric pump (1) for conveying media through a flexible tube (2), comprising a housing (4), which can be closed by means of a door (3), a displacing device (5) for applying a pressing force to the flexible tube (2), an abutment portion (6), on which the flexible tube (2) is arranged and is supported with respect to the pressing force applied by the displacing device (5), and an adjustable preloading device (7), by means of which the displacing device (5) and/or the abutment (6) are supported with adjustable yielding or preloaded against each other in order to enable adjustment of the pressing force that is or can be applied to the tube (2). The displacing device (5), the abutment portion (6) and the preloading device (7) are arranged within the housing when the housing (4) is closed, and the preloading device (7) can be adjusted from the outside when the housing (4) is closed, without the housing (4) having to be opened for this purpose.

Description

Volumetric pump

Description Technical area

The present invention relates to a volumetric pump for conveying media through a flexible hose with a closable by a door or flap housing, a displacement means for introducing a pressing force on the flexible hose, an abutment portion on which the flexible hose is arranged and on which the one by the

Displacement device presses on pressure-exerted flexible hose and an adjustable biasing means by means of which the displacement means (e.g., slider peristaltic or pump rotor) and / or the anvil are mounted with an adjustable compliance or biased against each other to allow an adjustment of the introduced or introduced on the hose pressure force.

State of the art

From the prior art are various infusion tube pumps

(Squeeze pumps) known. These are used, for example, an active substance with a certain delivery rate from a drug reservoir on a

To promote infusion tube to or into a patient.

Infusion tube pumps are usually designed as volumetric pumps, which displace a volume in the infusion tube from the outside. This has the advantage that the displacement device (slide peristalsis / pump rotor) remains unaffected by the media carried in the hose or does not come into contact with the media. In such pumps, the pressure force of the peristalsis provides a

Significant contribution to the delivery accuracy It is therefore necessary, this

To adjust pressure force precisely, for example, to adjust them to the different elasticity of different tubes (disposable). It is a long-felt need in competent professional circles, the conveying accuracy and pressure stability of To further improve infusion tube pumps, for example, to be able to administer drugs in even more precise dosages.

Furthermore, there is the risk of uncontrolled in known solutions

Failure in the adjusting device for the pressing force, eg. By the breakage of a spring. In such a case, the peristaltic slides may lift off from their corresponding counter bearing, resulting in an uncontrolled amount of drug entering or exiting the patient. Brief description of the invention

Object of the present invention is therefore, means and ways

to provide with which the delivery accuracy can be improved in a volumetric pump.

The above object is achieved by a device having the features of

Claim 1 solved. Advantageous developments are the subject of the dependent claims.

Basically, a volumetric pump according to the invention for conveying media through a flexible hose has the following features / components:

a closable by means of a door / flap / lid housing,

a displacement device, in particular a slide peristaltic or a pump rotor, for mounting / inserting a tube (traveling along the tube)

Pressure force on the flexible hose,

an abutment portion (abutment) on which the flexible hose is arranged and supported as a result of the up / introduced by the displacement means pressure force and

an adjustable biasing means by which the

Displacement device and / or the abutment portion are mounted with an adjustable compliance or biased against each other, with an adjustment of the (by the displacement means) on the hose up / introduced or on / engageable Andruckkraft is possible. According to the invention are the displacement device, the

Counter bearing portion and the biasing means in the closed state of the housing disposed within the same and the biasing means is adjustable in the closed state of the housing from the outside, without requiring the housing must be opened. In other words, the volumetric pump according to the invention is designed to be displaced by means of a displacement device

(Slider peristaltic / pump rotor) by the compression of a defined

Hose volume with a defined, by a biasing device

set / introduced, contact pressure to a certain amount

To promote fluid / agent / infusion solution. The individual components of the

Displacement device (the pump mechanism) are so constructively matched to each other and to the housing, that by the

Biasing device generated pressing force of the displacement device from the outside and without disassembly or opening of the housing can adjust / set.

In known solutions, it is quite possible, the pressure force of the

To set the displacement device (peristaltic), but this is an opening or dismantling of the pump (the pump housing) required. This is due to the reassembly of the pump and the resulting tolerances, inaccuracies or deviations and the achievable

Delivery accuracy is therefore limited. The arrangement according to the invention described above therefore not only offers ergonomic advantages for the user but also enables improved conveying accuracy, since the pressure force of the

Pretensioner can be adjusted with the housing closed and the

Dimensional deviations / tolerances can be compensated during reassembly of the pump.

According to a preferred aspect of the invention, the biasing means may be adapted to be adjusted purely mechanically. Preferably, the

Biasing means comprise an adjusting spring, that is, a spring element whose biasing force can be adjusted by the method of an actuator. According to a preferred embodiment, the displacement device may comprise a number of peristaltic slides, which are for example mounted linearly displaceable in a stationary slide housing (in a sliding direction) and are driven via an eccentric shaft with a number of (angularly offset) eccentric cams. In other words, the displacement device can be designed as a slide peristaltic. In such a slide peristalsis, the number of slides is preferably driven by the eccentric shaft in such a way that it displaces

successively in a wave motion push a defined volume in the flexible hose in a conveying direction. The slider housing can either be a separate inner housing, which is arranged inside the (pump) housing or also be an integral section of the (pump) housing, on which the peristaltic slides are mounted linearly displaceable. Preferably, the peristaltic slides thus mounted have a single degree of freedom in the sliding direction. The eccentric shaft can preferably be mounted rotatably and can be driven to rotate, preferably by a motor.

Basically, however, it is also possible to equip the (squeezing) pump with a pump rotor, on whose circumference a number of angularly spaced pressure rollers is mounted, wherein the flexible hose arcuately around the

Pump rotor is guided and thereby applies against the also arcuate about the flexible hose (around the pump rotor) formed abutment portion quasi as a hose guide.

In a preferred aspect, the pusher housing / rotor housing may be fixed to the (pump) housing to provide precise guidance of the peristaltic pusher / pressure rollers. In the prior art is the

Introducing the adjustable pressure often the whole

Slider housing / rotor housing biased toward the anvil portion. The resulting mobility of the storage of the

Peristaltic pushers / pressure rollers, however, are reflected in a less accurate promotion. According to a preferred embodiment, the eccentric shaft or the pump rotor shaft may be resiliently mounted relative to the slide housing.

Preferably, the biasing means bias the eccentric shaft / pump rotor shaft directly or indirectly toward the abutment portion, so as to generate the pressing force.

According to a further preferred aspect of the invention, the eccentric shaft (the slider peristaltic) can be pivotably mounted on the pendulum arm via a pendulum arm on the slide housing (fixed relative to the housing). The eccentric shaft itself is rotatably mounted on the pendulum arm in such an embodiment.

According to a preferred embodiment, the biasing device in the transverse direction to the sliding direction, in particular in the direction perpendicular to

Sliding direction and perpendicular to the orientation of the inserted in the housing

Hose, act. This has the background that the housing of volumetric pumps in the sliding direction and in the tube insertion direction due to the space required in these directions usually larger dimensions / edge lengths than perpendicular to these two directions (usually the vertical direction). By aligning the biasing device perpendicular to the sliding direction and the tube loading direction so the distance of the biasing device can be reduced to the housing outer surface to facilitate an adjustability of the same from the outside. Particularly preferably, the eccentric shaft can be mounted on the pivotable relative to the slide housing pendulum and the biasing means can, for example. Via a boom arm of the pendulum, in the transverse direction to

Shifting direction apply a torque to the pendulum, which counteracts the torque generated by the pressing force of the slider peristalsis on the pendulum.

According to a preferred embodiment, the biasing means is an adjusting screw;

a spring element, which is arranged axially displaceable and substantially concentric with the adjusting screw; and a spring holder which is axially displaceable and substantially concentric with the adjusting screw and adapted to hold an axial end of the spring element in a specific axial position relative to the adjusting screw,

respectively.

According to a further preferred aspect of the invention, the spring holder, in particular via a self-locking thread pairing, be so connected with adjusting screw that it is due to a rotational movement of the Einstellschraub in

Forced displacement displaces axial direction. In this way, the biasing means can be carried out such that the pressing force by a simple

Rotational motion can be adjusted. A self-locking execution of the thread pairing can be an unintentional adjustment / procedure of the spring holder, eg. As a result of

Preload force, prevent.

According to a preferred embodiment, the spring holder on the housing or the slider housing, in particular by a positive connection, linearly displaceable and rotationally secured to be stored. According to a preferred embodiment, the adjusting screw can be rotatably mounted on the housing and / or the slider housing and / or the pendulum arm. More preferably, the adjusting screw having a circumferential detent, by means of which the adjusting screw in a number of predetermined angular increments relative to the housing can be latched.

According to a further preferred aspect of the invention, the spring element may be formed as a compression spring. More preferably, the spring element may be formed as an axial wave spring. In this way, space can be saved in the axial direction of the spring element. Even more preferably, the spring element / the wave spring may be formed / shaped in such a way that it can not rotate after a break and retains the stored force. If the spring of the counterpressure bearing breaks, an uncontrolled flow will occur immediately in both Directions (depending on the pressure level). The use of the wave spring is safe at this point, as in a fraction of a turn, the spring force is almost maintained.

According to a preferred embodiment, the volumetric pump may have a through-bore or recess in the housing and / or the

Slider housing, which is corresponding to, in particular concentric with, the biasing device is formed to provide accessibility to the same. It is advantageous if the through-hole / recess is sealed by a sealing device to prevent the ingress of dirt into the

To prevent housing interior.

The invention will be explained below with reference to preferred embodiments with reference to the accompanying figures. The figures are merely schematic in nature and are for the sole purpose of understanding the invention. The same elements are provided with the same reference numerals.

Show it:

Fig. 1 is a schematic sectional view through an inventive

volumetric pump according to a preferred embodiment of the invention;

FIG. 2 is an exploded view of a volumetric pump displacement device according to the preferred embodiment; FIG. 3 is a rear perspective view of the volumetric pump displacement device according to the preferred embodiment;

4 is a detailed view of an adjustable biasing device according to a preferred embodiment;

Fig. 5 is a diagram of the balance of forces in the displacement device; and Fig. 6 is a schematic view of another preferred embodiment of a volumetric pump according to the invention of the radial design.

In medical technology, the use of volumetric pumps is known. In such pumps, the pressure force of peristaltic makes a significant contribution to the delivery accuracy. It is therefore necessary to adjust the pressure force of the peristalsis as precisely as possible. In known pumps, such an adjustment of the pressure force of the peristaltic is possible only in a disassembled or opened state of the pump housing. Due to the assembly-related position tolerances of the individual components arising during reassembly of the pump, the achievable accuracy of adjustment of such pumps is limited. Object of the present invention is therefore a pump mechanism with higher

To provide adjustment accuracy. This is achieved in particular by the fact that the individual components of the pump are matched to one another such that the adjustment of the pressure force of the peristaltic can take place in the closed state of the pump housing (without dismantling the pump).

1 shows a volumetric pump 1 for conveying media through a flexible hose 2 according to a preferred embodiment of the invention. More specifically, it is an infusion tube pump, which can supply or supply a means of action from an agent reservoir (not shown) at a predetermined delivery rate via an infusion line to a patient. For this purpose, the volumetric pump 1 basically has a door 3

lockable housing 4. In operation, the flexible hose 2 is arranged between the door 3 and the housing 4. In this arrangement, the hose 2 is provided between a displacement device 5 arranged in the housing 4 and an abutment section 6 formed by the door 3, the abutment section 6 forming an abutment to a contact pressure generated by the displacement device 5.

The displacement device 5 shown in FIGS. 2 and 3

volumetric pump 1 is designed as a slide peristalsis mechanism. As such, it has a number of (peristaltic) sliders 8 (here twelve) which are in a slide housing 9 are mounted linearly movable. The slides 8 are driven by an eccentric shaft 10, which has a number of slides 8 corresponding number of eccentric cam 10.1, which are each arranged corresponding to a slider 8. The eccentric cam 10.1 of the illustrated eccentric shaft 10 are each offset by 30 ° relative to the respective adjacent eccentric cam 10.1, so that, in a driven by a motor 1 1 rotation of the eccentric shaft 10, by the eccentric cam 10.1 in their

Linear movement forcibly guided slide 8, promote a volume in a conveying direction in a substantially sinusoidal displacement movement.

The slide housing 9 is fixedly arranged on the pump housing 4 in order to allow the most accurate possible guidance of the slide 8. In the example shown, the slide housing 9 is formed as a separate housing (inner body), which is advantageously attached to the pump housing 4 (outer body) positively and / or non-positively. In the example shown, the attachment of the

Slider housing 9 on the housing 4 by means of pressed pin. However, all conventional fastening methods are considered, for example by means of other fastening means such as screws, a positive connection or a press or welded connection. The slider housing 9 may also be formed as a stoffeinstückiger portion of the housing 4.

Both slider housing 9 and the abutment portion 6 are thus set in the illustrated voiumetric pump with respect to the pump housing 4. The adjustable pressure force of the peristaltic slide 8 relative to the abutment portion 6 is consequently realized via the mounting of the eccentric shaft 10. This is the

Eccentric shaft relatively movable to the remaining components of the

Displacement device 5 stored. In the example shown, the eccentric shaft 10 is pivotable relative to the slider housing 9 via a pendulum arm 9.1 mounted on a slider housing hinge 9.2. To generate the adjustable pressing force, the pendulum arm 9.1 is biased by means of the adjustable biasing means 7 such that the eccentric shaft 10 rotatably mounted on the pendulum arm 9.1 is urged in the direction of the abutment portion 6 (see Fig .. 1). Accordingly, those of the Eccentric shaft 10 positively driven slide 8 a force application, corresponding to the biasing force of the biasing device. 7

In order to ensure the adjustability of the introduced by the biasing means 7 in the peristaltic mechanism force, the biasing means 7 in the illustrated preferred embodiment as (in this case, three-part)

Spring adjustment formed. The spring adjustment is shown in the

Displacement device 5 as adjustable pressure-loaded spring formed between a boom 9.4 of the valve body 9 and a

Jib 9.5 of the pendulum arm 9.1 is tensioned to bias the eccentric shaft in the direction of the abutment portion.

As best seen in FIGS. 2 and 3, the pretensioning device is arranged essentially transversely to the sliding direction of the peristaltic slides 8. The biasing means 7 thus generates a torque about the axis of rotation of the slide housing hinge 9.2, about which the pendulum arm 9.1 is pivotable, which is opposite to the torque generated by the pressing force of the peristaltic valve 8. The vertical orientation of the biasing direction and the sliding direction of the peristaltic slide 8 relative to each other has the advantage that the distance to the pump housing 4 in the transverse direction to the sliding direction is shorter than in the sliding direction or in tube loading direction. This is due to the fact that volumetric pump housings are generally cuboid and have the shortest edge length in a direction transverse to the sliding direction and to the tube loading direction (usually the vertical direction). In other words, the accessibility of the adjustable pretensioning device 7 can be improved from outside the housing 4 by such a structural design, since a smaller distance must be bridged.

In order to provide the adjustability of the biasing means 7 in the assembled state of the housing 4, in the illustrated pump is a

Through hole 12 through the housing 4 and provided by the boom 9.4 of the slider housing 9, to which the biasing means 7 is arranged concentrically and through which the biasing means 7 is accessible. As can be seen from FIG. 4, the access to the spring adjustment in the illustrated example is by a sealing device 13 (which here has a screw plug and a sealing ring) sealed to prevent ingress of dirt particles in the pump gearbox. Adjacent to the access to the adjustable pretensioning device 7 shown in FIG. 4 are also on the outside of the pump housing 4

Markers 14 are provided, which the user with an increase or

Reduction of the pressure force of the peristaltic indicate the corresponding direction of rotation.

In the illustrated preferred embodiment, the biasing device 7 formed here as a spring adjustment is constructed in three parts from an adjusting screw 7.1, a spring element (wave spring) 7.2 and a spring retainer 7.3 (retaining ring). The adjusting screw is, as can be seen in Figure 3, rotatably mounted on the boom 9.4 of the slide housing 9 and the boom 9.5 of the pendulum arm 9.1. The spring holder 7.2 acts via an internal thread with an external thread of

Adjusting screw 7.1 together and thus proceeds in a rotational movement of the adjusting screw 7.1 relative to this in the axial direction. For this purpose, the spring holder 7.2 also acts in such a form-fitting manner with the slide housing 9 that this is secured against rotation or co-rotation with the adjusting screw 7.1 and yet mounted axially movable relative to the slide housing. This is achieved in the example shown in that the spring holder 7.3 an integral

Fork portion forms, which a rib 9.3 of the valve body. 9

positively receives. Stop surfaces 9.6 on the slide housing 9 limit the possible compression of the spring element 7.2.

The spring element 7.2 is advantageously arranged such that it with its axial ends a shock with the spring holder 7.3 and the boom 9.4 of the

Pendulum arm 9.1 forms. In this way, the spring element 7.2 can preload the eccentric shaft 10 mounted on the pendulum arm 9.1 in the direction of the abutment section 6. A rotation of the adjusting screw 7.1 triggers an axial movement of the spring holder 7.3, as a result of which the spring element 7.2 is compressed or relaxed. An adjustment of the introduced on the pendulum arm 9.1 biasing force is thus made possible by a simple rotation of the adjusting screw 7.1, which by the

Through hole / recess 12 is accessible. The spring element 7.2 is formed in the illustrated preferred embodiment as a wave spring. This has the advantage that wave springs

need comparatively little space in the axial direction to apply the same force as many other types of springs. In addition, the wave spring - im

Contrary to conventional (spiral) compression springs - be designed so that when a break at one point of the spring element 7.2, the two fragments resulting from the fracture can not rotate relative to each other. This is particularly advantageous for the present medical application, since in this way, even with a failure of the spring element 7.2, the biasing force stored in the same can be securely maintained. If this were not the case, it could result in a failure of the spring element 7.2 to fluctuations in the delivery rate and thus to an uncontrolled drug delivery.

The internal thread of the spring holder 7.3 and the external thread of

Adjusting screw 7.1 are formed in the example shown as a self-locking thread (eg., As trapezoidal thread) to prevent the axial position of the spring holder 7.3 changed due to the biasing force or to ensure that the set by the user pressure force is maintained. At the adjusting screw 7.2, a circumferential crown-shaped detent 15 is provided, which cooperates with a corresponding detent portion 16 (eg. A triangular-shaped snap-in lug) of the valve body 9 to an unintentional Versteilen the adjusting 7.1. (in addition to the self-locking thread) to prevent. The detent 15, 16 also gives the user a better haptic and acoustic feedback when going through the angular steps, when this adjusts the pressing force by means of the biasing device 7.

Fig. 5 shows a schematic representation of a balance of forces within the illustrated displacement device 5. The eccentric shaft 10 urges the slider 8 in the direction of the flexible hose 2 to effect a displacement. This is held by the fixed abutment portion 6 whereby a restoring force FR arises, which on the eccentric shaft 10 and thus also on the boom 9.1 (on which the eccentric shaft 10 is rotatably mounted). Consequently, a torque is created on the slide housing hinge 9.2, on which the pendulum arm 9.1 is pivotally mounted. A perpendicular to the main body of the pendulum arm 9.1 oriented

Arm 9.5 undergoes a biasing force Fv by the spring element 7.2, which is aligned perpendicular to the return force FR and counteracts the torque generated by the restoring force FR.

In Fig. 6 is an alternative embodiment of an inventive

volumetric pump 1, which in this case not as

Schieberperistaltikpumpe but as a radial peristaltic pump

(Peristaltic pump) is executed. According to the preceding

described embodiment, the radial peristaltic pump 1, a closable by means of a door 3 housing 4. In the housing 4 is a

Insertion recess formed with a substantially arcuate outer edge, which represents the abutment portion 6. The displacement device 5 is formed in the embodiment shown in Fig. 6 as a pump rotor 5, which is rotatably mounted in the housing 4 and a number (here three) of pressure rollers or shoes 5.1 has. The pump rotor 5 is arranged within the recess so that it forms an arcuate gap in conjunction with the part-circular edge of the same (ie the abutment portion 6), in which the flexible tube 2 is inserted or inserted. During a rotation of the pump rotor 5, the hose 2 undergoes a pressure force traveling in the axial direction of the hose (in the circumferential direction of the pump rotor 5) by the pressure rollers 5.1, which compresses the hose 2 to a defined extent in cooperation with the abutment portion 6 and in this way Moves volume in a conveying direction / promotes. Also in the radial volumetric pump 1, the pressing force is made adjustable. In the illustrated example, the pump 1 for this purpose has two separate adjusting springs 7, with which the abutment portion 6 and the pump rotor 5 are each biased against each other (towards each other). According to the invention, both adjusting springs 7 are arranged in the housing 4 (for example in a through-bore in the same) in such a way that they can be adjusted from the outside, without the door 3 having to be opened or the housing 4 being dismantled. The abutment portion 6 is mounted relative to the rest of the housing 4 relatively movable in the example shown, to bias it against the pump rotor 5 to enable. Preferably, the biasing force of the biasing device 7, which applies the biasing force to the pump rotor 5 and thus urges it in the direction of the abutment portion 6, is introduced into the rotor axis 5.2.

Of course, it suffices to implement the invention, a single

Provide biasing device 7, which biases either the pump rotor 5 or the abutment portion 6 toward the other component 5, 6.

In summary, the volumetric pump 1 according to the invention is therefore characterized by various design measures (such as, for example, the mutually perpendicular

Alignment of the sliding and the biasing direction or the use of an axial on pressure loaded wave spring) adapted to the pressure force of

Displacement device (peristaltic mechanism) from the outside and without disassembly of the housing 4 can be adjusted. For the user, this means that the pressure force could even be adjusted without the tube 2 (disposable) would have to be removed.

REFERENCE CHARACTERS:

1 volumetric pump;

2 flexible hose;

3 door / pump flap;

4 housing;

5 displacement device;

5.1 pressure rollers / sliding shoes;

5.2 rotor axis;

6 abutment section;

7 adjustable pretensioner;

7.1 adjusting screw;

7.2 spring element;

7.3 spring holder;

8 slides;

9 slide housing;

9.1 pendulum arm;

9.2 slide housing hinge;

9.3 rib;

9.4 Extension arm of the valve body

9.5 cantilever arm of pendulum arm;

9.6 stop surfaces

10 eccentric shaft;

10.1 eccentric cam;

1 1 engine;

12 through hole;

13 sealing device;

14 mark;

15 detent;

16 detent section.

Claims

claims

1 . Volumetric pump (1), in particular infusion pump, for conveying media through a flexible hose (2) with

- A closable by means of a door or flap (3) housing (4);

- A displacement device (5), in particular a slide peristalsis, for applying / introducing a pressing force on the flexible hose (2);

- An abutment portion (6) on which the flexible hose (2) is arranged and on which the flexible hose (2) relative to the through

Displacement device (5) introduced supporting pressure force is supported; and

- An adjustable biasing means (7), by means of which the

Displacement device (5) and / or the abutment portion (6) are mounted biased at least in sections with an adjustable biasing force or biased against each other to allow an adjustment of the hose (2) introduced or introduced pressure force,

characterized in that

the displacement device (5), the abutment portion (6) and the

Biasing means (7) are arranged in the closed state of the housing (4) within the same such that

the biasing device (7) in the closed state of the housing (4) is adjustable from the outside, without requiring that the housing (4) must be opened.

2. volumetric pump (1) according to claim 1, characterized in that the biasing means (7) as a purely mechanical spring adjustment (7.1, 7.2, 7.3) is formed, which from outside the housing (4) is accessible.

3. volumetric pump (1) according to claim 1 or 2, characterized in that the displacement means (5) comprises a number of peristaltic slides (8) which in a fixed slide housing (9) in a sliding direction

are mounted linearly displaceable and are driven by an eccentric shaft (10), which in particular on a pendulum arm (9.1) and by means of the biasing means (7) against the slide housing (9) is resiliently mounted.

4. volumetric pump (1) according to one of claims 1 to 3, characterized in that the biasing means (7), the biasing force on the

Eccentric shaft (10), in the displacement device (5) initiates.

5. volumetric pump (1) according to claim 3 or 4, characterized in that the biasing means (7) is designed such that through this

introduced biasing force is aligned transversely to the sliding direction of the peristaltic slide (8).

6. volumetric pump (1) according to one of claims 1 to 5, characterized in that the biasing means (7)

an adjusting screw (7.1);

a spring element (7.2), in particular a wave spring, which is arranged axially displaceable and substantially concentric with the adjusting screw (7.1); and a spring retainer (7.3) which is axially displaceable and substantially concentric with the adjusting screw (7.1) and adapted to hold an axial end of the spring element (7.2) in a specific axial position relative to the adjusting screw (7.1),

having.

7. Volumetric pump (1) according to claim 6, characterized in that the spring holder (7.3), in particular via a self-locking thread pairing, in such a way with adjusting screw (7.1) is connected, that he is due to a

Rotary movement of the adjusting screw (7.1) moves forcibly guided in the axial direction.

8. volumetric pump (1) according to claim 6 or 7, characterized in that the adjusting screw (7.1) rotatably on the housing (4) and / or the

Slider housing (9) is mounted and a detent (15), by means of which the adjusting screw (7.1) in a number of predetermined angular increments relative to the housing (4) and / or the slide housing (9) can be latched.

9. volumetric pump (1) according to one of claims 6 to 8, characterized in that the spring element (7.1) is designed as a wave spring and in its geometry such that it can not rotate after a break.

10. volumetric pump (1) according to one of the preceding claims, characterized by a through hole (12) or recess in the

Housing (4) and / or the slide housing (4), which correspond to,

in particular concentric with, the biasing means (7) is formed to provide accessibility to the same.