NL2004121C2

NL2004121C2 - Dispensing system and method for dispensing a fluid.

Info

Publication number: NL2004121C2
Application number: NL2004121A
Authority: NL
Inventors: Haske Zadelhoff
Original assignee: Ceratec Ceramic Bearings B V
Priority date: 2010-01-20
Filing date: 2010-01-20
Publication date: 2011-07-21

Description

Dispensing system and method for dispensing a fluid Field of the invention

The invention relates to the field of dispensing systems for dispensing predefined quantities of a fluid, and the invention relates to the field of methods for dispensing the fluid.

5

Background of the invention

Published patent application GB2099930 discloses a hydraulic ball pump. The pump comprises a rotor which rotates around a central pin which comprises a delivery duct and a suction duct which are open radially at the circumferential zone of the pin. The 10 rotor comprises a member, for example of a plastic construction, in which cylinders are embedded in which balls are provided as pistons. When the rotor rotates a centrifugal force swings the balls in a outwards direction. At the end of the cylinder the balls hit a circular surface constituted by a ring. The ring is positioned around the rotor, but the central point of the ring has an offset with regard to the rotation axis of the rotor. At a first region of the 15 ring the balls are pushed into the cylinder such that the cylinder is emptied into the delivery duct. At a second region of the ring the balls are allowed by the ring to move further outwards. If the rotor rotates with a high enough speed a centrifugal force pulls the balls in the outward direction and a liquid is sucked into the cylinder.

The hydraulic ball pump may be used to dispense an amount of liquid per 20 time unit. The size of the cylinders is known. Multiplying the size of the cylinders with the number of emptied cylinders per time unit results in a delivered amount of liquid during the time period. By controlling the number of rotations during a specific period of time, the amount of delivered liquid during the specific period of time is controlled. However, the hydraulic ball pump can only be used to deliver an accurate amount of liquid in an 25 uninterrupted stream. The rotor has to rotate at a high enough speed to fill the cylinders. Especially, during starting and a stopping the rotation of the rotor the centrifugal force is not high enough which results in a suction of an uncontrollable amount of liquid into the cylinders. Thus, interrupting the operation of the hydraulic ball pump of the published patent application, for example, to obtain an interrupted stream of liquid by dispensing a 30 first amount of liquid at an instant, and a second amount of liquid at a later instant, results in inaccurate dispensing.

2

Summary of the invention

It is an object of the invention to provide a dispensing system which is able to accurately dispense a quantity of a fluid in an interrupted stream.

A first aspect of the invention provides a dispensing system as claimed in 5 claim 1. A second aspect of the invention provides a method for dispensing a fluid as claimed in claim 15. Advantageous embodiments are defined in the dependent claims.

A dispensing system for dispensing predefined quantities of fluid in accordance with the first aspect of the invention comprises a cylindrical body which 10 encloses a cavity. The cylindrical body comprises a bore that extends from the cavity to an outer surface of the cylindrical body. The dispensing system further comprises a plunger which is provided in the bore. The plunger defines within the bore a first sub-space at a first end of the bore, and defines a second sub-space at a second end of the bore. The plunger is movable in a first direction and a second direction which is opposite to the first 15 direction. The moving of the plunger modulates a size of the first sub-space. The dispensing system further comprises a support member which cooperates with the cylindrical body. The cylindrical body is mounted within or around the support member and the cylindrical body is rotatable relative to the support member. The support member is configured to provide an inlet and an outlet. At the first end of the first sub-space an inlet 20 is provided to the first sub-space when the cylindrical body is in a first relative radial position. Also, at the first end of the first sub-space an outlet is provided to the first subspace when the cylindrical body is in a second relative radial position. The first relative radial position is different from the second relative radial position. The dispensing system is configured to push the plunger in the first direction and to push the plunger in the second 25 direction. The plunger is pushed in the first direction when the cylindrical body is in the first relative radial position in order to fill the first sub-space with the fluid through the inlet. The plunger is pushed in the second direction when the cylindrical body is in the second relative radial position in order to exhaust the first sub-space and by releasing the fluid to the outlet.

30 The cylindrical body rotates relative to the support member, which means that they rotate at other speeds and/or in another direction. For example, the cylindrical body may rotate, while the support member has a fixed position, however, in another embodiment the cylindrical body may have a fixed position and the support member may rotate. The cylindrical body is mounted within or around the support member. Thus, a 3 surface of the cylindrical body is opposite a surface of the support member and the two surfaces move relative to each other.

In the first relative radial position of the cylindrical body, the cylindrical body is relatively positioned with respect to the support member such that the inlet is at the 5 first end of the bore. In the second relative radial position of the cylindrical body, the cylindrical body is relatively position with respect to the support member such that the outlet is at the first end of the bore.

The dispensing system initially fills the first sub-space with fluid when the cylindrical body is in the first relative radial position. In the first relative radial position the 10 plunger is pushed in the first direction for filling the first sub-space with the fluid. By pushing the plunger in the first direction the first sub-space becomes larger in size which initially results in a reduction of the pressure in the first sub-space. In the first relative radial position the first end of the bore is at the inlet and the inlet may deliver fluid to the first sub-space. The reduced pressure results in the suction of fluid into the first sub-space 15 from the inlet. The movement of the plunger modulates the size of the first sub-space.

Thus, the pushing of the plunger modulates the size of the first sub-space and as such the pushing determines how much fluid is sucked into the first sub-space.

The inlet is a terminus of an inlet duct, or a flexible inlet hose, or another means which supplies the fluid, and the inlet is the terminus at which the fluid may fill the 20 first sub-space when the cylindrical body is in the first relative radial position. The outlet is a terminus of a outlet duct, or a flexible outlet hose, or another means which is capable of carrying away the dispense fluid, and the outlet is the terminus at which the fluid is received from the first sub-space when the cylindrical body is in the second relative radial position.

25 When the cylindrical body is not in the first relative radial position and not in the second relative radial position the first sub-space is sealed by the surface of the support member that is opposite the surface of the cylindrical body, in other words, the two surfaces are substantially close to each other such that the first end of the bore is sealed such that the fluid can not leave the first sub-space.

30 Subsequently, the cylindrical body and/or the support member rotate such that the cylindrical body becomes in the second relative radial position. In the second relative radial position the plunger is pushed in the second direction which is opposite to the first direction. Thus, the size of the first sub-space is reduced. Further, in the second relative radial position the first end of the bore is at the outlet. The pushing results in 4 exhausting the first sub-space via the outlet and as such releasing a known amount of fluid via the outlet.

A predefined amount of fluid may be dispensed by going through a multiple cycles of filling the first sub-space with the fluid and emptying the first sub-space. In every 5 cycle a known amount of fluid is transferred from the inlet to the outlet. Interrupting the rotation of the cylindrical body and/or the support member defines the end of transferring a fluid from the inlet to the outlet. The number of cycles multiplied by the known amount of fluid that is transferred during each cycle defines the amount of dispensed fluid. Because the amount of fluid that is transferred from the inlet to outlet via the first sub-space is 10 known accurately, the amount of dispensed fluid is accurately known as well. If subsequently the same or another amount of fluid has to be dispensed, the same or another amount of cycles of filling and exhausting the first sub-space has to be ran through. Thus, the dispensing system according to the first aspect of the invention is able to dispense very accurately pre-defined amounts of fluid in an interrupted stream.

15 The accuracy of the dispensing system does not depend on the rotation speed of the cylindrical body and/or the support member in order to get the bore partly filled with the fluid. The rotation of the cylindrical body and/or the support member is only required to position the cylindrical body in the first relative radial position and to rotate the cylindrical body to the second relative radial position. The filling and the exhaustion of the 20 first sub-space is performed by pushing the plunger in the first and the second direction at the first relative radial position and the second relative radial position of the cylindrical body, respectively. For such pushing multiple mechanical options are possible of which a few are discussed in the embodiments. It is to be noted that the pushing the plunger does not include the effect of a centrifugal force which provides a pulling force to the objects 25 which rotate and of which the centre of mass does not coincide with the rotation axis.

It is to be noted that the first relative radial position may also be a first relative radial position interval, and that the second relative radial position may also be a second relative radial position interval. The pushing of the plunger in the first direction or second direction may be performed in the whole interval or during a sub-interval of the 30 interval and does not necessarily depend on one specific first relative radial position or one specific second relative radial position. The functioning of the dispensing system depends on the pushing in the first direction when the first end of the bore is at least partly opposite the inlet, and depends on the pushing in the second direction when the first end of the bore is at least partly opposite the outlet.

5 5

It is to be noted that the fluid may be a gas or a liquid.

In an embodiment the outer surface is a radially outwards facing surface of the cylindrical body.

In an embodiment, the dispensing system comprises a first pushing member and/or a second pushing member. The first pushing member is for pushing the plunger in the first direction when the cylindrical body is in the first relative radial position. The second pushing member is for pushing the plunger in the second direction when the 10 cylindrical body is in the second relative radial position.

In an embodiment, the first pushing member and/or the second pushing member comprises an excentric element being positioned within or around the cylindrical body to push the plunger in the first direction or in the second direction.

An excentric positioned element is a relative simply manufacturable element 15 which is very effective in pushing the plunger. If the excentric element is positioned within the cylindrical body, the circumferential surface of the execentric element is at least at one region of the circumferential surface further away from a rotation axis of the cylindrical body and/or the support member than other regions of the circumferential surface. The region that is further away from the rotation axis may push the plunger in the first direction 20 or in the second direction. If the excentric element is positioned around the cylindrical body, at least a region of the radially inwards oriented surface of the excentric element is closer to the rotation axis of the cylindrical body and/or the support member than other the other regions of the radially inwards oriented surface. The region that is closer may push the plunger in the first direction or in the second direction. The excentric element 25 transforms a rotation into a force to the plunger in the first direction or the second direction. Various embodiments of the excentric element are possible. In an embodiment the excentric element is a cylinder excentrically positioned in the cavity of the cylindrical body such that a central axis of the cylinder does not coincide with the rotation axis. In an embodiment the excentric element is a ring excentrically positioned around the cylindrical 30 body such that a central axis of the ring does not coincide with the rotation axis. In an embodiment the excentric element comprises a protrusion which has a location such that the protrusion is near the first end of the bore when the cylindrical body is positioned at the first relative radial position, or the excentric element comprises a protrusion which has a 6 location such that the protrusions is near the second end of the bore when the cylindrical body is positioned at the second relative radial position.

In another embodiment, the first pushing member and/or the second pushing member comprises a wheel to cooperate with the cylindrical body in operational use. The 5 wheel is rotatable relative to the cylindrical body and a rotation axis of the wheel does not coincide with a rotation axis of the cylindrical body and/or the support member. The wheel comprises a protrusion for pushing the plunger in one of the first direction and the second direction.

A wheel is an effective solution for pushing the plunger in the first and/or 10 the second direction. A wheel with a protrusion comprises on its circumference a profile which is able to cooperate with a surface of the cylindrical body, like for example gears do. The wheel comprises a protrusion which is received by the cylindrical bore in order to push the plunger in the first direction or the second direction. The rotation of the wheel, relative to the cylindrical body, results in the insertion of the protrusion in the cylindrical 15 bore. The protrusion transforms a rotation of the wheel into a pushing force to the plunger.

In an embodiment, the rotation of the wheel is driven by the cylindrical body. This allows the wheel to rotate in a synchronized manner with the cylindrical body. No separate actuator is required for rotating the wheel. In an embodiment, the protrusion is leaveshaped. A leave-shape is advantageous because it allows smooth interaction between the 20 cylindrical body and the protrusion, for example, the protrusion is gradually inserted in the cylindrical bore during the rotation without interruptions. In an embodiment, the wheel comprises a plurality of protrusions. In another embodiment, the plurality of protrusions are equally distributed on the circumference of the wheel, which is a surface of the wheel which is radially outwards oriented with respect to a rotation axis of the wheel.

25 In another embodiment, the first and/or the second pushing member comprises a spring. Using a spring may be an advantageous pushing member because, for example, energy stored in the spring may be released at the moment at which the plunger has to move in the first direction or in the second direction. In an example, the spring is positioned at the second end of the bore, and the spring stores energy when the plunger is 30 pushed in the first direction, and the spring releases the energy by pushing the plunger in the second direction when the cylindrical body is at the second relative radial position. Using a spring reduces the number of elements that have to interact with the cylindrical body. It reduces the complexity of the dispensing system.

7

In another embodiment, the dispensing system comprises a fluid supply system for supplying the fluid under pressure to the inlet. The pressure must be high enough to move the plunger in the first direction when the cylindrical body is in the first relative radial position such that the first sub-space is filled with the fluid.

5 Using pressure for pushing the plunger in the first direction results in less mechanical parts in the dispensing system, which reduces the wear of parts and as such the maintenance costs are reduced. Furthermore, in most production system, the fluid is supplied by a pump which delivers the fluid under pressure. As such, no changes to, or only small adaptations to, the production system are required to obtain the required 10 pressure.

In a further embodiment, the plunger comprises a spherical plunger. Spherical plungers are relative cheap to manufacture with a very high accuracy. Further, the sphere has a small contact surface with the wall of the cylindrical bore, which reduces the amount of wear of the plunger and the wall of the cylindrical bore. Further, if the 15 plunger protrudes partly out of the cylindrical bore and makes contact with for example the support member, the contact surface is small and the spherical plunger may start to roll, which further reduces the friction between the spherical plunger and, in this embodiment, the support member.

In another embodiment, at least one of the following elements of the 20 dispensing system comprises a ceramic material: the cylindrical body, the plunger, the support member, the first pushing member, or the second pushing member. Ceramic materials are well resistant against wear and well resistant against damaging influences of malicious substances. The resistance against wear allows an accurate operation of the metering system during a long period of time without the need of maintenance or the need 25 of replacing parts of the metering system. Or, for example, it may be possible to dispense a liquid with a very low or a very high pH value. In an embodiment, the elements of the dispensing system are entirely of the ceramic material. In an embodiment, the ceramic material is a combination of zirconium oxide and silicon nitride.

In an embodiment, the cylindrical body comprises a plurality of bores and 30 each one of the plurality of bores comprises a plunger. Like the bore, the plurality of bores extend from the cavity to the outer surface of the cylindrical body. The plurality of bores allow the dispensing system to be more efficient. The first sub-space of each one of the plurality of bores may be filled with the fluid when the specific each one of the plurality of bores is at the first relative radial position and subsequently the first sub-space of each one 8 of the plurality of bores may be emptied when the specific each one of the plurality of bores is at the second relative radial position. Fewer rotations of the cylindrical body relative to the support member are required to fill and empty a specific number of first subspaces. Further, a more constant output stream will be obtained at the outlet.

5 In a further embodiment, the plurality of bores are equally distributed over the circumference of the cylindrical body. By means of the equally radial distribution of the bores, the amount of fluid that is dispensing of by the system does not depend on the specific relative radial position of the cylindrical body. For example, independent of a specific relative radial position, rotating the cylindrical body for 180 degrees relative to the 10 support member, results in the same number of bores passing the inlet and passing the outlet, and as such the dispensing of the same amount of liquid. Further, when the cylindrical body rotates relative to the support member, a more constant stream of fluid may be obtained by the cylindrical body of the embodiment.

In a further embodiment, the dispensing system comprises a plurality of 15 inlets and a corresponding number of outlets. A plurality of inlets and a corresponding number of outlets allows the dispensing system to operate more efficiently. When the cylindrical body is rotated relative to the support member over, for example, an angle of 360 degrees, the first sub-space of the bores may be filled and emptied a plurality of times. Thus, fewer rotations are needed to dispense a specific predefined amount of fluid. In a 20 further embodiment, the inlets and outlets are equally distributed over the radially outwards oriented face of the support member.

In another embodiment, the dispensing system comprises a further support member which cooperates with the cylindrical body. The further support member is rotatable relative to the cylindrical body and is preferably not rotatable relative to the 25 support member. The further support member is configured to provide at the second end of the bore a further outlet to the second sub-space for exhausting the second sub-space to release the fluid to the further outlet when the cylindrical body is in the first relative radial position. The further support member is further configured to provide a the second end of the bore a further inlet to the second sub-space for filling the second sub-space with the 30 fluid when the cylindrical body is in the second relative radial position.

The plunger is moved at the first relative radial position in the first direction. The moving of the plunger modulates the size of the first sub-space and the second sub-space. If the first sub-space becomes larger, the second sub-space becomes smaller. If the first sub-space becomes smaller, the second sub-space becomes larger.

9

Without introducing additional pushing means the moving of the plunger may be used for two functions: filling the first sub-space and emptying the second sub-space when the cylindrical body is at the first relative radial position, and emptying the first sub-space and filling the second sub-space when the cylindrical body is at the second relative radial 5 position. The further support member provides the further inlet and the further outlet to support the filling and emptying of the second sub-space. Using the second sub-space for the dispensing of the fluid is advantageous because it allows a more efficient dispensing system without requiring additional means for pushing the plunger in the first and/or in the second direction.

10 In an embodiment, the fluid is a liquid. The liquid may be a composition of liquids and the liquid may contain dissolved substances. In an embodiment the liquid complies with a strong acid, which may be a liquid with a pH value smaller than 3. In another embodiment, the pH value is large, preferably larger than 12.

In an embodiment, the dispensing system further comprises an actuator 15 which is used to rotate the cylindrical body relative to the support member. The dispensing system further comprises a controller that is connected to the actuator and controls the rotation of the cylindrical body relative to the support member to obtain the predefined quantities of fluid. An accurate dispensed predefined quantity of fluid is obtained by accurately controlling the rotation of the cylindrical body relative to the support member, 20 which is performed by the actuator and the controller.

According to a second aspect of the invention a method is provided for dispensing predefined quantities of fluid by means of a dispensing system. The dispensing system comprises a cylindrical body, a plunger and a support member. The cylindrical body encloses a cavity and the cylindrical body comprises at least one bore that extends 25 from the cavity to an outer surface of the cylindrical body. The plunger is provided in the bore for defining a first sub-space of the bore at the first end of the bore and a second subspace of the of the bore at a second end of the bore. The plunger is movable in a first direction and a second direction being opposite to the first direction for modulating a size of the first sub-space. The support member cooperates with the cylindrical body and the 30 cylindrical body is mounted within or around the support member. The support member is configured to provide at the first end of the bore an inlet to the first sub-space when the cylindrical body is in a first relative radial position, and at the first end of the bore an outlet to the first sub-space when the cylindrical body is in a second relative radial position. The second relative radial position is different from the first relative radial position. The 10 method comprises a step of rotating the cylindrical body relative to the support member to position the cylindrical body in the first relative radial position. In a further step of the method the plunger is pushed in the first direction when the cylindrical body is in the first relative radial position to fill the first sub-space with the fluid through the inlet. In a further 5 step of the method the cylindrical body is further rotated relative to the support member to position the cylindrical body in the second relative radial position. In a further step of the method the plunger is pushed in the second direction when the cylindrical body is in the second relative position to exhaust the first sub-space to release the fluid into the outlet.

The method according to the second aspect of the invention provides the 10 same benefits as the dispensing system according to the first aspect of the invention and has similar embodiments with similar effects as the corresponding embodiments of the system.

These and other aspects of the invention are apparent from and will be 15 elucidated with reference to the embodiments described hereinafter.

It will be appreciated by those skilled in the art that two or more of the above-mentioned embodiments, implementations, and/or aspects of the invention may be combined in any way deemed useful.

20 Modifications and variations of the system, the method, which correspond to the described modifications and variations of the system, can be carried out by a person skilled in the art on the basis of the present description.

Brief description of the drawings 25 In the drawings:

Fig. 1 schematically shows an embodiment of the dispensing system of which the cover is removed,

Fig. 2 schematically shows a cross-cut of the dispensing system along line AA’, 30 Fig. 3 schematically shows a detail of the cross-cut of the dispensing system,

Fig. 4. schematically shows a cross-cut of another embodiment of the dispensing system, 11

Fig. 5. schematically shows a cylindrical body and two wheels with a protrusion of another embodiment of the dispensing system,

Fig. 6a schematically shows a support member with a recess and a wheel of another embodiment of the dispensing system, 5 Fig. 6b schematically shows the wheel of Fig. 6a interacting with a cylindrical body of the another embodiment of the dispensing system, and

Fig. 7 schematically shows a flow diagram of the method of the invention.

It should be noted that items denoted by the same reference numerals in 10 different Figures have the same structural features and the same functions. Where the function and/or structure of such an item have been explained, there is no necessity for repeated explanation thereof in the detailed description.

The figures are purely diagrammatic and not drawn to scale. Particularly for clarity, some dimensions are exaggerated strongly 15

Detailed description A first embodiment is shown in Fig. 1. A three dimensional view of a dispensing system 100 is shown of which a cover is removed. The dispensing system 100 20 comprises a side housing 106 and a cylindrical body 104 which is connected to a rotation axis 112. The cylindrical body 104 acts as a rotor and rotates together with its rotation axis around an imaginary rotation axis 114. The side housing 106 has a fixed position.

However, in other embodiments the housing may rotate and the cylindrical body may have a fixed position. The inner surface 102 of the side housing 106 has, seen in a top view, a 25 shape of a circle, however, the circle is positioned excentric with respect to the imaginary rotation axis 114. The cylindrical body 104 comprises a plurality of bores 110. Each one of the plurality of bores 110 comprises a spherical plunger 108. As seen in Fig. 1, some of the spherical plungers 108 partly protrude out of some of the bores 110 at the location where a gap between the inner surface 102 of the side housing 106 and the cylindrical body 104 is 30 large enough to allow the cylindrical plungers to protrude partly out of the cylindrical body 104. It may already be seen that, if the cylindrical body rotates around the imaginary rotation axis 114, the spherical plungers 108 are pushed in a radially inwards direction when the specific bore 110, in which the specific spherical plunger 108 is provided, 12 reaches the location where the inner surface 102 of the side housing 106 almost touches the radially outwards oriented surface 111 of the cylindrical body.

A cross-cut of the dispensing system 100 along line AA’ is shown in Fig. 2. Cylindrical body 104, which is connected to the rotation axis 112, is shown. The 5 cylindrical body 104 and the rotation axis 112 rotate together around an imaginary rotation axis 114. The side housing 106 of the dispensing system is shown and at the area 208 it is seen that there is a gap between the inner surface 102 of the side housing 106 and the radially outwards oriented surface 111 of the cylindrical body 104. At position 210 the inner surface 102 of the side housing 106 and radially outwards oriented surface 111 10 almost touch each other.

The cylindrical body 104 comprises a plurality of bores of which two bores 214, 216 are shown in the cross-cut. Each one of the plurality of bores comprises a spherical plunger. Bore 214 comprises spherical plunger 212 and bore 216 comprises spherical plunger 218. As seen at the left end of the cross-cut, the spherical plunger 212 15 protrudes partly out of the bore 214. At the right end of the cross-cut, the spherical plunger 218 is completely pushed inside the bore 216 by the excentrically positioned inner surface of the side housing 106.

The cross-cut of Fig. 2 further shows a support member 204 which is in the embodiment the base of the dispensing system 100 and has together with the side housing 20 106 a fixed position. The support member 204 provides an inlet 202 and an outlet 206. The inlet 202 is the end point of an inlet duct 203 which is provided in the support member 204. The inlet 202 has a radial position at a location close to area 208 where the gap between the side housing 106 and the cylindrical body 104 is at its maximum. The outlet 206 is the end point of an outlet duct 207 which is provided in the support member 204.

25 The outlet 206 has a radial position close to area 210 where the gap between the side housing 106 and the cylindrical body 104 is at its minimum.

The inlet 202 receives via a duct in the support member 204 a fluid from a supply system (not shown). The supply system provides the fluid under a high pressure. This pressure is high enough to move the spherical plunger 212 in a radially outwards 30 direction and thereby a part of the bore 214 is filled with the fluid. The amount of fluid that may stream in the bore 214 depends on the size of the bore, the size of the spherical plunger 212 and the distance by which the spherical plunger 212 may protrude out of the bore 214 when the bore 214 is opposite the inlet 202. Thus, a specific design of the dispensing system 100 allows a specific amount of liquid to be taken in the bore 214.

13

The cylindrical body 104 rotates around the imaginary rotation axis 114. In the example of Fig. 2, a rotation of 180 degrees is required to get the bore 214 at a radial position in front of the outlet 206. After about 140 degrees rotation, and continuing towards the complete 180 degrees rotation, the eccentrically positioned inner surface 102 5 of the side housing 106 pushes the spherical plunder 212 in a radially inwards oriented direction until the situation as shown at the right end of Fig. 2 is reached. During the radially inwards oriented movement of the spherical plunger 212 the fluid is emptied into the outlet 206. If the cylindrical body rotates another 180 degrees, the bore 214 ends up in front of the inlet once again, and the high enough pressure of the fluid moves the pherical 10 plunger 212 in a radially outwards direction and the bore 214 is filled with the fluid.

The bore 216 goes through the same cycle of receiving fluid from the inlet 202 and exhausting the fluid in the outlet 206, with the only difference that bore 216 is emptied when bore 214 is filled and vice versa.

It is known how many bores are provided in the cylindrical body 104 and 15 what the angular distance between the bores is. Further, it is known with which amount of fluid the bores are filled when they are opposite the inlet 202, and as such how much fluid is released when the bores are opposite the outlet 206. Thus, the amount of dispensed fluid depends on the angle by which the cylindrical body 104 is rotated around the imaginary rotation axis 114. If a specific amount of fluid has to be dispensed, the cylindrical body 20 104 has to be rotated by a specific angle around the imaginary rotation axis 114.

It is to be noted that the inlet 202 and/or the outlet 206 may be formed by a grove in a surface of the support member 204 that is opposite a surface of the cylindrical body 104. The grooves may be connected to the inlet duct 203 and the outlet duct 207. The inlet that is formed by a groove provides over, for example, an angular distance of 30 25 degrees the fluid to one or more first sub-spaces of respective one or more bores. The outlet that is formed by a groove receives over, for example, an angular distance of 30 degrees the fluid form one or more first sub-spaces of respective one or more bores. It results in a more continuous dispense stream of fluid.

It is to be noted that in the shown embodiment of Figs. 1 and 2 the inner 30 surface 102 of the side housing 106 forms a circle that is excentrically positioned with respect to the rotation axis 114. In another embodiment the inner surface 102 of the side housing 106 encloses the cylindrical body 104 and the inner surface 102 comprises a groove that allows the plungers 212,218 to mode in the first direction when a bore with the respective plunger 212, 218 is in the first radial position. At the second radial position the 14 groove is absent and the inner surface 102 of the side housing 106 pushes the plungers 212, 218 in the second direction. Thus, the groove forms together with a part of the inner surface 102 a circle that is excentrically positioned with respect to the rotation axis 114.

In an embodiment, one or more elements of the dispensing system 100 are 5 manufactured of a ceramic material. Manufacturing techniques for ceramic materials are well known from the handbook “Brevier Technische Keramik” of the “Informationszentrum Technische Keramik”. The one or more elements may comprise the cylindrical body 104, the support member 204, the side housing 106, the cover (not shown), the (spherical) plungers 108, 212, 218 or the rotation axis 112. All other elements 10 which are provided in other embodiment and which are in contact with the fluid may be manufactured of the ceramic material as well. A ceramic material that is well resistant against malicious fluids, for example fluids with a very low pH value, is a combination of zirconium oxide and silicon nitride.

In another embodiment, the rotation axis 112 is connected to an actuator 15 which rotates the cylindrical body 104 relative to the support member 204. The actuator is controlled by a controller. The controller controls the actuator such that the dispensing system dispenses a predefined amount of fluid. Thus, the controller determines how many rotations are required to dispense the predefined amount of fluid and controls the actuator such that the specific number of rotations is made by the cylindrical body 104.

20 Fig. 3 schematically shows a detail of the cross-cut of Fig 2. The left end of the cross-cut is shown. A cross-cut of a cylindrical body 104 is shown. The cylindrical body 104 comprises a bore 214. The first end of the bore 214 is indicated with number 312 and the second end is indicated with reference number 306. In the bore 214 is provided a spherical plunger 212. The spherical plunger 212 substantially touches the wall of the bore 25 214 and as such the spherical plunger 212 divides the bore 214 in a first sub-space 310 and a second sub-space 308. The spherical plunger 212 is movable in a first direction 304 and a second direction 302. The moving of the spherical plunger 212 modulates the size of the first sub-space 310 and the second sub-space 308.

Fig. 3 further shows a cross-cut of the side housing 106 of which the 30 radially inwards oriented face 102 is positioned some distance away from the radially outwards oriented face 111 of the cylindrical body 104. As shown in Fig. 1 and Fig. 2, the distance between the radially inwards oriented face 102 of the side housing 106 and the radially outwards oriented face 111 varies. Especially in the section shown in Fig. 3 the gap has a maximum distance.

15

Fig. 3 further shows a support member 204, which is fixed to the side housing 106. The cylindrical body 104 rotates relative to the support member 204. The support member 204 provides an inlet 202 to the first sub-space 310. The inlet 202 is positioned at a radially outwards oriented face of the support member 204 such that, when 5 the bore 214 is at the position where the gap between the side housing 106 and the cylindrical body 104 is as large as possible, the bore 214 may receive the fluid from the inlet 202.

In the embodiment of Fig. 1, 2 and 3, the fluid is received from a supply system (not shown) which provides the fluid under a high pressure. The fluid under high 10 pressure provides a pushing force to the right side of the spherical plunger 212. Consequently, the spherical plunger 212 moves in the first direction 304 and as a consequence the first sub-space 310 becomes larger and is filled with the fluid. The distance along which the spherical plunger 212 is moved in the first direction 304 is limited by the side housing 106.

15 Fig. 4 shows another embodiment of a dispensing system 400. A cross-cut of the dispensing system 400 is shown. In the middle of the cross-cut is shown a support member 404 which comprises an inlet duct 406 and an outlet duct 416. Around the support member is positioned a cylindrical body 408 of which a first bore 414 and a second bore 418 are shown. The first bore 414 comprises a cylindrical plunger 402 and the second bore 20 418 comprises another cylindrical plunger 420. Around the cylindrical body is provided a further support member 410 which comprises a further inlet duct 412 and a further outlet duct 422.

The further support member 412 is not rotatable with respect to the support member 404. The cylindrical body 408 is rotatable with respect to the support member 25 404. The inlet 413 to the bore 414 of the further inlet duct 412 is positioned opposite the outlet 415 of the outlet duct 416. The inlet 419 to the bore 418 of the inlet duct 406 is positioned opposite the outlet 412 of the further outlet duct 422. An imaginary rotation axis 417 around which the cylindrical body 408 rotates is indicated in Fig. 4.

The dispensing system 400 is connected to a fluid supply system (not 30 shown) which provides a fluid under a pressure. The pressure is high enough to move the cylindrical plungers 402, 420 when the fluid is provided to the bores 414 and 418.

In a relative radial position of the cylindrical body 408 as shown in Fig. 4, the further inlet duct 412 provides the fluid under the pressure to bore 414 and as a consequence the cylindrical plunger 402 moves towards the imaginary rotation axis 417.

16

The radially outwards positioned sub-space of bore 414 is filled with the fluid and at the same time the radially inwards positioned sub-space of the bore 414 is emptied via the outlet duct 416. In the relative radial position of the cylindrical body 408 the inlet duct 406 provides the fluid under the pressure to bore 418 and consequently the cylindrical plunger 5 420 moves away from the imaginary rotation axis 417. The radially inwards positioned sub-space of bore 418 is filled with liquid and the radially outwards positioned sub-space of bore 418 is emptied in the further outlet duct 422.

If the cylindrical body 408 rotates relative to the support member 404 to a relative radial position in which bore 414 is in between the inlet duct 406 and the further 10 outlet duct 422, the process of filling and emptying of the bores 414, 418 is performed in the opposite direction as described in the previous paragraph.

By controlling a number of rotations of cylindrical body 408 relative to the support member 404 a specific number of bores may be filled and emptied and as such an accurately dispensed quantity of fluid may be obtained. It is to be noted that the 15 embodiment of Fig. 4 may dispense, for example, twice the same amount by each one of the outlet ducts 416, 422 independently, or the sum of the amounts of fluid provided by the two outlet ducts 416, 422 may form the dispensed quantity of fluid.

It is to be noted that the embodiment as shown in Fig. 4 is not limited to two inlet ducts, or two outlet ducts in total. The support member 404 may comprise for 20 example two inlet ducts and two outlet ducts, and the further support member 410 may also comprise two further inlet ducts and two further outlet ducts. If this is the case, the output ports and the input ports of inlet ducts and outlet ducts, respectively, may alternate over the radially outwards oriented face of the support member 404, and the output port and the input ports of the further inlet ducts and the further outlet ducts, respectively, may be 25 positioned opposite the input ports and the output ports of outlet ducts and inlet ducts, respectively.

In Fig. 5 a part 500 of another embodiment of a dispensing system is shown. A cross-cut of a cylindrical body 502 is shown which is rotatable relative to a support member (not shown) of the dispensing system. The cylindrical body 502 and/or the support 30 member rotate around rotation axis 513. The cylindrical body comprises a cavity and comprises a plurality of bores 504, 506, 512 that extend from the cavity to the radial outwards oriented face of the cylindrical body 502. Each one of the bores 504, 506, 512 comprises a plunger (not shown) for modulating a size of a first sub-space of the bore and a size of a second sub-space of the bore.

17

Fig. 5 shows two wheels 508, 514 which are rotatable relative to the cylindrical body 502. The rotation axis 507, 515 of the wheels 508, 514 do not coincide with the rotation axis 513 of the cylindrical body 502. Wheel 508 rotates in an opposite direction as the rotation direction of the cylindrical body 502. Wheel 514 rotates in the 5 same direction as the rotation direction of the cylindrical wheel 502 - however, wheel 514 makes more rotation per time unit than the cylindrical body 502.

Each one of the wheels 508, 514 has a protrusion 510, 516. The wheels 508, 514 and the cylindrical body 502 cooperate such that the protrusions 510, 516 of the wheels 508, 514 are received by the bores 504, 506, 512. The cylindrical body 502 and the 10 wheel 508, 514 interact as gears.

At the left end of the picture is shown that the protrusion 510 is received by bore 512. During the inwards movement of the protrusion 510 into bore 512 the plunger, which is provided in the bore 512, is pushed in a radially inwards direction. At the right end of the picture is shown that the protrusion 516 is received by bore 506. Protrusion 516 15 pushes the plunger of bore 506 in a radially outwards direction.

The pushing of the plungers results in increasing one of the two sub-space of the bore, and the decrease of the other one of the two sub-space of the bore. The increase of the one of the sub-spaces may be used to suck fluid into the one of the subspaces. When the one of the sub-spaces increases, the pressure sinks in the one of the sub-20 spaces and if the one of the sub-spaces is opposite an inlet, the fluid is sucked into the one of the sub-spaces. The decrease of the other one of the sub-spaces may be used to exhaust the other one of the subspaces and release the fluid into an outlet.

In Figures 6a and 6b parts of another embodiment of a dispensing system are shown. In Fig. 6a is shown a support member 603 in a three dimensional view. When 25 the parts of the dispensing system are assembled together, the column 602 of support member 603 will be positioned in a cavity 614 of a cylindrical body 610. Support member 603 comprises in the column 602 a recess 606 in which a wheel 604 is provided and the wheel 604 partly protrudes out of the recess 606. The recess 606 may have a connection with an inlet duct for providing fluid to the recess 606.

30 Fig. 6b shows the cylindrical body 610 which will receive the column 602 of the support member 603 in the cavity 614 of the cylindrical body 610. The cylindrical body 610 is connected to a rotation axis 612 for rotating the cylindrical body 610 relative to the support member 603. The cylindrical body 610 comprises a plurality of bores 608.

18

Fig. 6b further shows the wheel 604. The wheel 604 comprises 4 leave shaped protrusions 616. In particular, the cooperation between wheel 604 and the cylindrical body 610 is shown in Fig. 6b. The wheel 604 and the cylindrical body 610 cooperate as gears. The protrusions 616 are successively received by the successive bores 5 608. Once one of the protrusions 616 enters one of the bores 608, the protrusion pushes a plunger, which is provided in each one of the bores 608, in a radially outwards direction. As discussed at Fig. 6a, the recess 606 in which the wheel 604 is positioned may be connected to an inlet duct which provide a fluid. When the protrusion 616 pushes the plunger in the radially outwards direction, fluid is sucked via the recess 606 into the bore 10 608. The recess 606 acts as the inlet.

The bores 608 are emptied at another relative radial position. It may be done by another wheel which acts as a pushing member, or it may be done by an element which is excentrically positioned around the cylindrical body 610.

Fig. 7 shows an embodiment of the method 700 for dispensing predefined 15 quantities of fluids according to the second aspect of the invention. The dispensing is performed by means of a dispensing system. The dispensing system comprises a cylindrical body, a plunger and a support member. The cylindrical body encloses a cavity and the cylindrical body comprises at least one bore that extends from the cavity to an outer surface of the cylindrical body. The plunger is provided in the bore for defining a 20 first sub-space of the bore at the first end of the bore and a second sub-space of the of the bore at a second end of the bore, and the plunger is movable in a first direction and a second direction being opposite to the first direction for modulating a size of the first subspace. The support member cooperates with the cylindrical body and the cylindrical body is mounted within or around the support member. The support member is configured to 25 provide at the first end an inlet to the first sub-space when the cylindrical body is in a first relative radial position, and at the first end an outlet to the first sub-space when the cylindrical body is in a second relative radial position being different from the first relative radial position. In a first step of the method the cylindrical body rotates 702 relative to the support member to position the cylindrical body in the first relative radial position. In a 30 second step the plunger is pushed 704 in the first direction when the cylindrical body is in the first relative radial position for filling the first sub-space with the fluid through the inlet. In a third step of the method the cylindrical body is further rotated 706 relative to the support member to position the cylindrical body in the second relative radial position. In a fourth step the plunger is pushed 708 in the second direction when the cylindrical body is 19 in the second relative radial position for exhausting the first sub-space to release the fluid to the outlet.

The embodiments of the invention may be used to dispense fluids which are 5 mechanically or chemically aggressive, for example, fluids with a very low or very high pH value, and/or fluids that comprise particles. Examples of such fluids are fuels, polymer solutions, pigment solutions, or hying oil. Most of these fluids have to be dispensed very accurately to obtain a product which is manufactured within a small error bandwidth.

10 It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not 15 exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures 20 cannot be used to advantage.

The following embodiments are considered advantageous: 1 A dispensing system (100, 400, 500) for dispensing predefined quantities of a fluid, the system comprising: 25 - a cylindrical body (104, 408, 502, 610) enclosing a cavity (614), wherein the cylindrical body (104, 408, 502, 610) comprises a bore (110, 214, 216, 414,418, 506, 512, 608) that extends from the cavity (614) to an outer surface (111) of the cylindrical body (104,408, 502,610), a plunger (108, 212, 218, 402, 420) provided in the bore (110, 214, 216, 30 414, 418, 506,, 512, 608) for defining a first sub-space (310) ofthe bore (110, 214, 216, 414, 418, 506,, 512, 608) at a first end (312) ofthe bore (110, 214, 216, 414, 418, 506,, 512, 608) and a second sub-space (308) ofthe bore (110, 214, 216, 414, 418, 506,, 512, 608) at a second end (306) of the bore (110,214,216,414, 418, 506,, 512, 608), wherein the plunger (108, 212, 218, 402, 420) being movable in a first direction (304) and a second 20 direction (302) opposite to the first direction (304) for modulating a size of the first subspace (310), a support member (204, 404, 603) for cooperating with the cylindrical body (104, 408, 502, 610), wherein the cylindrical body (104, 408, 502, 610) is mounted within 5 or around the support member (204, 404, 603) and the cylindrical body (104, 408, 502, 610) is rotatable relative to the support member (204, 404, 603), wherein the support member (204, 404, 603) is configured to provide at the first end (312) an inlet (202,419, 606) to the first sub-space (310) when the cylindrical body (104, 408, 502, 610) is in a first relative radial position, and at the first end (312) an outlet (206, 415) to the first sub-space 10 (310) when the cylindrical body (104, 408, 502, 610) is in a second relative radial position, and wherein the second relative radial position is different from the first relative radial position, wherein the dispensing system (100, 400, 500) is configured for: pushing the plunger (108,212,218, 402, 420) in the first direction (304) 15 when the cylindrical body (104, 408, 502, 610) is in the first relative radial position for filling the first sub-space (310) with the fluid through the inlet (202, 419, 606), and for pushing the plunger (108, 212, 218, 402, 420) in the second direction (302) when the cylindrical body (104, 408, 502, 610) is in the second relative radial position for exhausting the first sub-space (310) to release the fluid to the outlet (206, 415).

20 2. A dispensing system (100, 400, 500) according to embodiment 1, further comprising at least one of the following: a first pushing member (514, 604) for pushing the plunger (108, 212,218, 402, 420)in the first direction (304) when the cylindrical body (104, 408, 502, 610) is in the first relative radial position, and/or 25 - a second pushing member (106, 508) for pushing the plunger (108, 212, 218, 402, 420) in the second direction (302) when the cylindrical body (104, 408, 502, 610) is in the second relative radial position.

3. A dispensing system (100, 400, 500) according to embodiment 2, wherein the first pushing member (514, 604) and/or the second pushing member (106, 508) 30 comprises an excentric element (106) positioned within or around the cylindrical body (104, 408, 502, 610) for pushing the plunger (108, 212, 218, 402, 420) in the first direction (304) or in the second direction (302).

4. A dispensing system (100, 400, 500) according to embodiment 2, wherein the first pushing member (514, 604) and/or the second pushing member (106, 508) 21 comprises a wheel (508, 514, 604) for cooperating with the cylindrical body (104, 408, 502, 610) in operational use, wherein the wheel (508, 514, 604) is rotatable relative to the cylindrical body (104, 408, 502, 610), wherein a rotation axis (507, 515) of the wheel (508, 514, 604) does not coincide with a rotation axis (114, 417, 513) of the cylindrical body 5 (104, 408, 502, 610) and/or the support member (204, 404, 603), and wherein the wheel (508, 514, 604) comprises a protrusion (510, 516, 616) for pushing the plunger (108, 212, 218, 402, 420) in the first direction (304) or in the second direction (302).

5. A dispensing system (100, 400, 500) according to one of the previous embodiments, wherein the dispensing system (100, 400, 500) comprises a fluid supply for 10 supplying the fluid under pressure to the inlet(202, 419, 606), wherein the pressure is for moving the plunger (108, 212, 218, 402, 420) in the first direction (304) when the cylindrical body (104, 408, 502, 610) is in the first relative radial position to fill the first sub-space (310) with the fluid.

6. A dispensing system (100, 400, 500) according to one of the previous 15 embodiments, wherein the plunger (108, 212, 218, 402, 420) comprises a spherical plunger (108,212,218).

7. A dispensing system (100, 400, 500) according to one of the previous embodiments, wherein at least one of the following elements of the dispensing system (100, 400, 500) comprises a ceramic material: the cylindrical body (104, 408, 502, 610), 20 the plunger (108, 212, 218, 402, 420), the support member (204, 404, 603), the first pushing member (514, 604), or the second pushing member (106, 508).

8. A dispensing system according to embodiment 7, wherein the ceramic material is manufactured from zirconium oxide and silicon nitride.

9. A dispensing system (100, 400, 500) according to one of the previous 25 embodiments, wherein the cylindrical body (104, 408, 502, 610) comprises a plurality of bores (110, 214, 216, 414, 418, 506,, 512, 608) each comprising a plunger (108, 212, 218, 402, 420).

10. A dispensing system (100, 400, 500) according to embodiment 9, wherein the plurality of bores (110, 214, 216, 414, 418, 506,, 512, 608) are equally distributed over 30 the circumference of the cylindrical body (104, 408, 502, 610).

11. A dispensing system (100, 400, 500) according to one of the previous embodiments, comprising a plurality of inlets (202, 606) and a corresponding number of outlets (206).

22 12. A dispensing system (100, 400, 500) according to one of the previous embodiments further comprising a further support member (410) for cooperating with the cylindrical body (104, 408, 502, 610), wherein the further support member (410) is rotatable relative to the cylindrical body (104, 5 408, 502, 610) and not rotatable relative to the support member (204, 404, 603), wherein the further support member (410) is configured to provide at the second end (306) a further outlet (421) to the second sub-space (308) for exhausting the second sub-space (308) to release the fluid to the further outlet (421) when the cylindrical body (104, 408, 502, 610) is in the first relative radial position, 10 wherein the further support member (410) is further configured to provide at the second end (306) a further inlet (413) to the second sub-space (308) for filling the second subspace (308) with the fluid when the cylindrical body (104, 408, 502, 610) is in the second relative radial position.

13. A dispensing system (100, 400, 500) according to one of the previous 15 embodiments, wherein the fluid is a liquid.

14. A dispensing system (100, 400, 500) according to one of the previous embodiments further comprising: an actuator for rotating the cylindrical body (104, 408, 502, 610) relative to the support member (204, 404, 603), and 20 - a controller connected to the actuator for controlling the rotation of the cylindrical body (104, 408, 502, 610) relative to the support member (204, 404, 603) to obtain the predefined quantities of the fluid.

15. A method (700) for dispensing predefined quantities of a fluid by means of a dispensing system, wherein the dispensing systems comprises a cylindrical body, a 25 plunger and a support member, wherein the cylindrical body encloses a cavity and the cylindrical body comprises a bore that extends from the cavity to an outer surface of the cylindrical body, wherein the plunger is provided in the bore for defining a first sub-space of the bore at the first end of the bore and a second sub-space of the of the bore at a second end of the bore, wherein the plunger is movable in a first direction and a second direction 30 being opposite to the first direction for modulating a size of the first sub-space, wherein the support member is configured for cooperating with the cylindrical body, wherein the cylindrical body is mounted within or around the support member, wherein the support member is configured to provide at the first end an inlet to the first sub-space when the cylindrical body is in a first relative radial position, and at the first end an outlet to the first 23 sub-space when the cylindrical body is in a second relative radial position being different from the first relative radial position, the method comprising: rotating (702) the cylindrical body relative to the support member to 5 position the cylindrical body in the first relative radial position, pushing (704) the plunger in the first direction when the cylindrical body is in the first relative radial position for filling the first sub-space with the fluid through the inlet, further rotating (706) the cylindrical body relative to the support member to 10 position the cylindrical body in the second relative radial position, and pushing (708) the plunger in the second direction when the cylindrical body is in the second relative radial position for exhausting the first sub-space to release the fluid to the outlet.

15

Claims

A dosing system (100, 400, 500) for dosing predefined amounts of fluid, the system comprising: 5. a cylindrical body (104, 408, 502, 610) enclosing a cavity (614), the cylindrical body ( 104, 408, 502, 610) includes a bore (110, 214, 216, 414, 418, 506, 512, 608) extending from the cavity (614) to an outer surface (111) of the cylindrical body (104, 548, 502, 610), a plunger (108, 212, 218, 402, 420) provided in the bore (110, 214, 216, 414, 418, 506, 512, 608) for defining a first subspace ( 310) at a first end (312) of the bore (110, 214, 216, 414, 418, 506, 512, 608) and a second subspace (308) at a second end (306) of the bore (110, 214 (216, 414, 418, 506, 512, 608), the plunger (108, 212, 218, 402, 420) being movable in a first direction (304) and a second direction (302) opposite to the first direction (304) for modulating the size of the first subspace (310), a support member (204, 404, 603) for cooperating with the cylindrical body (104, 408, 502, 610), the cylindrical body (104, 408, 502, 610) within or around the support member (204,404, 603), and wherein the cylindrical body (104, 408, 502, 610) is rotatable with respect to the support member (204, 404, 603), the support member (204, 404, 603) being configured for providing an inlet port (202, 419, 606) to the first subspace (310) at the first end (312) if the cylindrical body (104, 408, 502, 610) is in a first relative radial position, and for providing an outlet opening (206, 415) at the first subspace (310) at the first end (312) if the cylindrical body (104, 408, 502, 610) is in a second relative radial position, and wherein the first relative radial position differs from the second relative radial position, wherein the dosing system (100, 400, 500) is configured for: pushing the plunger (108, 212, 218, 402, 420) in the first direction 30 (304) if the cylindrical body (104, 408 502, 610) is in a first relative radial position for filling the first subspace (310) with the fluid through the inlet port (202, 419, 606), and for pushing the plunger (108, 212, 218) , 402, 420) in the second direction (302) if the cylindrical body (104, 408, 502, 610) is in a second relative radial position for emptying the first subspace (310) to discharge the fluid via the outlet opening (206, 415).

A dosing system (100, 400, 500) according to claim 1, further comprising at least one of the following: a first pushing member (514, 604) for pushing the plunger (108, 212, 218, 402, 420) in the first direction (304) if the cylindrical body (104, 408, 502, 610) is in the first relative radial position, and / or, a second pushing member (106, 508) for pushing the plunger 10 ( 108, 212, 218, 402, 420) in a second direction (302) if the cylindrical body (104, 408, 502, 610) is in the second relative radial position.

A dosing system (100, 400, 500) according to claim 2, wherein the first pushing member (514, 604) and / or the second pushing member (106, 508) comprises an eccentric member (106) positioned within or around the cylindrical body (104, 408, 502, 610) for pushing the plunger (108, 212, 218, 402, 420) in a first direction (304) or in a second direction (302).

A dosing system (100, 400, 500) according to claim 2, wherein the first pushing member (514, 604) and / or the second pushing member (106, 508) comprises a wheel (508, 514, 604) for co-operating with the cylindrical body (104, 408, 502, 610) during use, the wheel (508, 514, 604) being rotatable relative to the cylindrical body (104, 408, 502, 610), with a rotation axis ( 507, 515) of the wheel (508, 514, 604) does not coincide with a rotation axis (114, 417, 513) of the cylindrical body (104, 408, 502, 610) and / or of the support member (204, 404, 603), and wherein the wheel (508, 514, 604) comprises a protrusion (510, 516, 616) for pushing the plunger (108, 212, 218, 402, 420) in the first direction (304) or in the second direction (302).

A dosing system (100, 400, 500) according to any of the preceding claims, wherein the dosing system (100, 400, 500) comprises a fluid supply for supplying the fluid to the inlet opening (202, 419, 606) under pressure wherein the pressure is for moving the plunger (108, 212,218,402,420) in the first direction (304) if the cylindrical body (104, 408, 502, 610) is in a first relative radial position for filling the first subspace (310) with the fluid.

A dosing system (100, 400, 500) according to any of the preceding claims, wherein the plunger (108, 212, 218, 402, 420) comprises a spherical plunger (108, 212, 218, 402, 420).

A dosing system (100, 400, 500) according to any of the preceding claims, wherein at least one of the following parts of the dosing system (100, 400, 500) comprises a ceramic material: the cylindrical body (104, 408, 502 , 610), the plunger (108,212, 218,402,420), the support member (204, 404, 603), the first pushing member (514, 604), or the second pushing member (106, 508).

A dosing system (100, 400, 500) according to claim 7, wherein the ceramic material is made from zirconium oxide and silicon nitride.

A dosing system (100, 400, 500) according to any of the preceding claims, wherein the cylindrical body (104, 408, 502, 610) has multiple bores (110, 214, 216, 414, 418, 506, 512, 608) each comprising a plunger (108, 212, 218, 402, 420).

A dosing system (100, 400, 500) according to claim 9, wherein the plurality of bores (110, 214, 216, 414, 418, 506, 512, 608) are evenly distributed around the circumference of the cylindrical body (104, 408 , 502, 610). 25

A dosing system (100, 400, 500) as claimed in any one of the preceding claims comprising a plurality of inlet openings (202, 206) and a corresponding number of outlet openings (206).

A dosing system (100, 400, 500) as claimed in any one of the preceding claims which comprises a further support member (204, 404, 603) for cooperating with the cylindrical body (104, 408, 502, 610), the further support member (204, 404, 603) is rotatable relative to the cylindrical body (104, 408, 502, 610) and is not rotatable relative to the support member (204, 404, 603), the further support member (204, 404, 603) is configured to provide a further outlet opening (421) at the second end (306) to the second subspace (308) for emptying the second subspace (308) to drain the fluid through the further outlet opening ( 421) if the cylindrical body (104, 408, 502, 610) is in the first relative radial position, the further support member (204, 404, 603) being configured to provide a second end (306) further i inlet opening (413) to the second partial cavity (308) for filling the second partial cavity (308) with the fluid if the cylindrical body (104, 408, 502, 610) is in the second relative radial position.

A dosing system (100, 400, 500) according to any of the preceding claims, wherein the fluid is a liquid.

A dosing system (100, 400, 500) according to any of the preceding claims, further comprising: 20. a drive means for rotating the cylindrical body (104, 408, 502, 610) relative to the support member (204, 404, 603), and a controller connected to the drive means for controlling the rotation of the cylindrical body (104, 408, 502, 610) relative to the support member (204, 404, 603) to obtain the predefined amounts of the fluid.

15. A method (700) for dosing predefined amounts of a fluid using a dosing system, the dosing system comprising a cylindrical body, a plunger, and a support member, the cylindrical body enclosing a cavity and a bore comprising extending from the cavity to an outer surface of the cylindrical body, wherein the plunger is provided in the bore for defining a first partial length at a first end of the bore and a second partial length at a second end of the bore, the plunger movable is in a first direction and a second direction opposed to the first direction for modulating the size of the first subspace, the support member being configured to cooperate with the cylindrical body, the cylindrical body being mounted inside or around the support part, wherein the support part is c is configured to provide an inlet opening at the first end if the cylindrical body is in a first relative radial position, and an outlet opening at the first end if the cylindrical body is in a second relative radial position, and wherein the first relative position differs from the second relative radial position, the method comprises: 10. rotating (702) the cylindrical body relative to the support member to the first relative radial position, pushing (704) the plunger in the first direction if the cylindrical body is in the first relative radial position, for filling the first subspace with the fluid through the inlet opening, 15. further rotating (706) the cylindrical body relative to the support member to the second relative radial position, and pushing (708) the plunger in the second direction if the cylindrical li body is in the second relative radial position, for emptying the first subspace to drain the fluid through the outlet opening. 20