Throttle Unit

Abstract

A throttle unit, in particular of a blow moulding device, includes a throttle and a position sensor. The throttle has an actuator and a drive unit including an electric motor for changing a position of the actuator. A throughflow cross section in a throughflow channel of a fluid can be changed by changing the position of the actuator. The drive unit is arranged at a first end of the actuator. The position sensor monitors the position of the actuator directly. The throttle unit makes it possible to set and adjust the throttle automatically in an accurate but nevertheless cost-effective manner.

Claims

1. A throttle unit, in particular of a blow moulding device, comprising a throttle and a position sensor, wherein the throttle has an actuator and a drive unit comprising an electric motor for changing a position of the actuator, wherein a throughflow cross section in a throughflow channel a fluid is changeable by changing the position of the actuator, wherein the drive unit is arranged at a first end of the actuator, wherein the position sensor directly monitors the position of the actuator.

2. The throttle unit according to claim 1, wherein the position sensor is arranged in a region of a second end of the actuator opposing the first end.

3. The throttle unit according to claim 2, wherein the actuator has a flow channel, through which fluid can flow, and wherein the actuator is configured to be closed at the second end relative to the flow channel.

4. The throttle unit according to claim 1, wherein the actuator has an end face at the second end, and wherein the position sensor faces this end face.

5. The throttle unit according to claim 1, wherein the first end and the second end define a longitudinal centre axis and wherein the actuator is rotatable about the longitudinal centre axis.

6. The throttle unit according to claim 1, wherein the position sensor is a magnetic field sensor, and wherein a magnet or a magnetisable element is arranged in the throttle.

7. The throttle unit according to claim 6, wherein the magnet or magnetisable element is arranged in or at an end region of the throttle.

8. The throttle unit according to claim 1, wherein the actuator has openings and/or recesses which form the flow channel, and wherein all openings and recesses of the flow channel are arranged at a distance from the second end.

9. The throttle unit according to claim 1, wherein the actuator has a basic structure in the form of a circular cylinder comprising a winding indentation which is configured to be open to the exterior and forms the flow channel.

10. The throttle unit according to claim 9, wherein the indentation has a development which has legs and a web connecting the two legs to each other.

11. The throttle unit according to claim 10, wherein the two legs extend approximately parallel to each other.

12. The throttle unit according to claim 11, wherein the two legs extend perpendicularly to the longitudinal centre axis of the actuator.

13. The throttle unit according to claim 1, wherein the electric motor has a motor shaft which is dynamically sealed, and wherein the dynamic seal the motor shaft is the only dynamic seal for sealing the throttle relative to an outer housing which receives the throttle.

14. A device comprising the throttle unit according to claim 1 and comprising an outer housing which has the duct channel, wherein the actuator is arranged in the duct channel, wherein the duct channel has an inlet opening for supplying the fluid into the flow channel of the actuator and an outlet opening for guiding the fluid away from the flow channel of the actuator, and wherein the inlet opening and the outlet opening are arranged transversely to a longitudinal centre axis of the actuator.

15. A device according to claim 14, wherein the throttle, at the end thereof remote from the actuator has a flange which acts to fix the throttle in the outer housing.

16. The throttle unit according to claim 6, wherein the magnet or the magnetisable element is arranged in the actuator.

17. The throttle unit according to claim 6, wherein the magnetic field sensor is a Hall sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The terms Fig., Figs., Figure, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings.

[0062] Preferred embodiments of the invention are described in the following with reference to the drawings, which are provided for illustrative purposes only and are not to be interpreted as restrictive. In the drawings:

[0063] FIG. 1 shows a perspective view of a valve block of a blow moulding device comprising the throttle unit according to the invention, wherein the valve block is shown in partial section,

[0064] FIG. 2 shows a perspective view of a position sensor of the throttle unit according to the invention as shown in FIG. 1,

[0065] FIG. 3 shows a schematic view of the throttle unit according to the invention in a first combination with a device,

[0066] FIG. 4 shows a schematic view of the throttle unit according to the invention in a second combination with a device,

[0067] FIG. 5 shows a partial section through a portion of the valve block as shown in FIG. 1 with a fitted throttle unit according to the invention,

[0068] FIG. 6 shows a perspective view of the throttle unit as shown in FIG. 1,

[0069] FIG. 7 shows a longitudinal section through the arrangement as shown in FIG. 5,

[0070] FIG. 8 shows a longitudinal section through a valve block with a fitted throttle unit according to the invention in a further embodiment,

[0071] FIG. 9 shows an actuator of the throttle unit according to the invention as shown in FIG. 7,

[0072] FIG. 10 shows the actuator as shown in FIG. 9 with a view of the development of the indentation thereof,

[0073] FIG. 11 shows an actuator of the throttle unit according to the invention in a second embodiment,

[0074] FIG. 12 shows an actuator of the throttle unit according to the invention in a third embodiment, and

[0075] FIG. 13 shows a portion of the throttle unit according to the invention with a fitted storage element.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0076] FIG. 1 shows a preferred field of application of the throttle unit according to the invention. The field of application is a housing block of a blow moulding machine, also referred to as a valve block. The valve block 1 has a through-hole 10 which is penetrated by a blowing pin. A blank of a body to be inflated, in particular a PET or PP bottle, can be arranged on or in the through-hole 10. Blow moulding machines of this type are widely known in the prior art and will therefore not be described in greater detail.

[0077] They have a plurality of process valves which are actuated at different times during the course of the blowing process in order to bring the blank into the desired shape by means of blowing air. In this view, a pilot valve 11 of a process valve is shown. Further process valves, more specifically a pre-blowing valve and a main blowing valve, are covered by a valve cover 13 and are therefore not visible in this figure.

[0078] A process fluid, in this case blowing air, can be guided into the valve block from the exterior via a throughflow channel 12. The portion of the throughflow channel 12 located between an inlet opening 120 and an outlet opening 121 in the region of the throttle 2 is shown in FIG. 5.

[0079] The valve block 1 is connected so as to be able to communicate with a control unit 80, which is connected to a machine control 81. The control unit 80 and the machine control are shown schematically in FIGS. 3 and 4.

[0080] A throttle unit according to the invention is arranged on or, as shown in this case, in the valve block 1. It comprises a throttle 2 and a position sensor 3.

[0081] The throttle 2 is configured to be substantially cylindrical and is introduced or inserted into a hole in the valve block 1. The casing of the throttle 2 is completely surrounded by the valve block 1. In FIG. 1, the valve block 1 is shown in a sectional view in this region so that the throttle 2 can be seen. In the actual valve block 1, only the end shown on the right in FIG. 1 can be seen from the exterior.

[0082] The position sensor 3 is arranged adjacent to the throttle 2 in the valve block 1. In this example, it is arranged at an end face of the throttle 2. A sealing blanking plug 4 closes a hole in the valve block 1, which leads to the throttle 2, from the exterior.

[0083] A fastening screw 5 fixes the throttle 2 at an end of the throttle 2 opposing the position sensor 3.

[0084] A preferred exemplary embodiment of a position sensor 3 is shown in FIG. 2. It preferably has an elongate shape. Consequently, it requires little space and can be inserted into a hole in the valve block 1 in a simple manner. The position sensor 3 can be configured without a housing, since the valve block 1 forms the protective housing thereof. The position sensor 3 has a preferably flat base plate 30, at the front free end of which a magnetic field sensor, preferably a Hall sensor 31, is arranged. Instead of a Hall sensor, other sensors can also be used, for example a magnetoresistive sensor.

[0085] As shown in FIG. 2, further elements can be arranged on the base plate 30. Preferably, a storage means 32 is provided in order to store measured values, but also correction values, locally. Preferably, an electronic unit 33 is provided in order to operate the magnetic field sensor and to transmit the measured values to the control unit 80.

[0086] At an end opposing the Hall sensor, the position sensor 3 has a plug connector 35 which is soldered onto the base plate 30 with a plug connector connection 34. The plug connector 35 protrudes from the valve block and acts as a second support point on the one hand and for connection to the control unit 80 on the other. The position sensor 3 is preferably releasably arranged in the valve block 1.

[0087] The throttle 2, more specifically an actuator 22 described below, constricts a throughflow cross section in the throughflow channel 12 and thus changes the throughflow volume. The position sensor 3 monitors the position of the throttle 2. More specifically, the position sensor 3 monitors the actuator 22 and thus determines the exact position thereof. The position of the actuator 22 is changed by means of an electric motor 21, which preferably has a gear mechanism 211.

[0088] An example of the manner in which the throttle unit can be operated and used is explained with reference to FIGS. 3 and 4.

[0089] A machine control 81, preferably a programmable logic controller (PLC), communicates with a control unit 80, also referred to as a control box. The control unit 80 acts on the electric motor 21 of the throttle 2 which, via an optional gear 211, changes the position of the actuator 22 of the throttle 2. This change is detected by the position sensor 3. The position sensor 3 reports the changed position to the control unit 80. Based on these reported data, and optionally in accordance with the machine control 81, the control unit changes the control data of the electric motor 21 and thus the position of the actuator 22. This is preferably carried out when resetting the process device, in particular the blow moulding machine, for example when a new type of hollow body is to be inflated or when the throttle 2 or another consumable part of the device ages or has been replaced. In this case, the machine control 81 preferably specifies a desired angle of the throttle 2.

[0090] In the variant shown in FIG. 4, regulation is also carried out during the production process. This is, however, preferably carried out exclusively between the switching cycles of the individual process valves, i.e. there is pressure in the throughflow channel 12, but the process fluid is not flowing.

[0091] For this purpose, a pressure sensor 9 is preferably provided, which measures the process pressure in the process 82, for example in the region of the preform. In this case, the machine control 81 preferably specifies a desired pressure or a desired pressure increase. The control unit automatically adapts the angle of the throttle 2 during the next blowing cycle, based on the information specified and taking into account the measured position of the actuator 22 and the pressure value of the pressure sensor 9. Preferably, regulation is not constant, and changes are rather only made between the blowing cycles in the event of divergence from desired values. In this way, a cost-effective electric motor, which has a sufficiently long service life due to the low number of switching cycles, can be used in the throttle 2.

[0092] A preferred exemplary embodiment of the throttle unit according to the invention is clearly shown in FIGS. 5 to 8.

[0093] The throttle 2 comprises the actuator 22 and a drive unit comprising a housing 20 and the electric motor 21. The housing 20 is preferably configured to be open at the top so that it forms a trough for receiving the electric motor 21. In other embodiments, the housing 20 is configured to be closed over the entire circumference thereof. The housing 20 is preferably configured in one piece. The actuator 22 is arranged at a front end, in the direction of insertion into the valve block 1. The actuator 22 and the housing 20, which is notionally completed to form a closed cylinder, preferably have an identical or an approximately identical outer diameter. The outer diameter is preferably only slightly smaller than the inner diameter of the hole in the valve block 1.

[0094] The right end of the housing 20 remote from the actuator 22 forms a flange 200 which acts as an external stop on the valve block 1. The fastening screw 5 fixes this end, and thus the throttle 2, in the hole in the valve block 1. For this purpose, the fastening screw 5 is received in an opening 28, shown in FIG. 6, in the region of the housing 20 adjacent to the flange 200.

[0095] An adjoining outer sealing ring 26 seals the throttle 2 from the exterior. The flange 200 is penetrated by a plug connector 27 which connects the electric motor 21 to the control unit 80.

[0096] The actuator 22 is likewise configured to be substantially cylindrical. It forms a flow channel 29 between an inlet opening 120 and an outlet opening 121 of the throughflow channel 12. This is clearly shown in FIG. 5. The portion of the throughflow channel 12, from the end shown leading to the exterior up to the inlet opening 120, is not visible due to the partial section in FIG. 1 and the sections shown in FIGS. 5, 7 and 8. It can, however, extend as desired within the valve block 1.

[0097] The actuator 22 is directly connected to a motor axle 210 of the electric motor 21. The fixing means used is preferably a grub screw 23.

[0098] The motor shaft 210 is dynamically sealed relative to the housing 20 by means of a sealing ring 25. Preferably, this is the only dynamic seal relative to the valve block or stationary components. An inner seal 24 seals the front end of the housing 20 facing the actuator 22 relative to the valve block 1.

[0099] The actuator 22 itself is not sealed. However, a sealing ring (shown in broken lines) is provided at the inlet opening 120 and a sealing ring (not shown) is provided at the outlet opening 121.

[0100] A magnet 6, preferably a permanent magnet, is arranged at the end of the actuator 22 facing away from the electric motor 21. In the examples shown in FIGS. 7 and 8, the magnet is a bar magnet which extends perpendicularly to the longitudinal centre axis L of the throttle 2. The magnet is arranged adjacent to the position sensor 3, wherein it is inserted into a hole arranged in the actuator 22 so that it is located adjacent to the end face of the actuator 22.

[0101] The magnet 6 is preferably arranged centrally relative to the longitudinal centre axis L, wherein the axis thereof, defined by the north and south poles thereof, extends perpendicularly to the longitudinal centre axis. If the actuator 22 is rotated about the longitudinal centre axis L by means of the electric motor 21, the magnetic field of the magnet 6 detected by the Hall sensor 31 changes and the change in the angle of rotation of the actuator can be detected. If a zero position of the actuator 22 is known, the effective angle of rotation, and thus the change in the throughflow cross section, can be calculated. The zero position of the angle of rotation is preferably a position in which the throughflow cross section is fully open or fully closed.

[0102] In other embodiments, the magnet 6 is a disc magnet, as shown in FIG. 11. In the figures, the dividing line within the magnet shows the north and south poles of the magnet 6. The measurement principle remains fundamentally the same. It is also possible to use other magnet shapes.

[0103] As is clearly shown in FIGS. 9 and 11, the actuator 22 is preferably configured in one piece. It has a substantially cylindrical basic structure, of which the end face facing the position sensor 3 is configured to be closed. This end face can have an indentation for the magnet 6, as illustrated in the embodiments shown in FIGS. 11 and 12. It is, however, preferably always closed relative to the flow channel 29.

[0104] The actuator 22 has an indentation 220 which winds around the circumference such that the remaining casing 221 forms an elevation. This indentation 220, together with the elevated casing region, forms the flow channel 29. The actuator 22 therefore does not have any through-openings for the flow channel 29. FIG. 10 shows the development of the indentation 220. It has two legs 223, which preferably extend parallel to each other. The legs 223 taper towards the respective free ends thereof. The legs 223 are preferably not of equal width. Preferably, the narrow leg faces the inlet opening 120 and constricts the throughflow cross section to the maximum possible extent.

[0105] The two legs 223 are connected to each other by a web 224. The web 224 is preferably also configured to be asymmetrical, wherein it preferably forms an angle from the leg 223 at the inlet to the second leg 223 at the outlet, as can be seen in FIG. 10.

[0106] The flow channel 29 can also take other forms.

[0107] In FIG. 11, the magnet 6 is a disc magnet. It is arranged in an indentation in the end face of the actuator 22. The remaining elements of the actuator 22 are preferably identical to those in the first exemplary embodiment.

[0108] In FIG. 12, the actuator has a projection 222 which acts as a positioning aid for the definition of the zero setting, i.e. the definition relating to the 0 position mentioned at the outset, of the throttle 2.

[0109] In FIG. 13, arranged at the rear end of the housing 20 facing away from the actuator 22 is a storage element 7, an RFID tag in this case, on which data can be stored when the throttle 2 is produced, but preferably also when the throttle 2 is in operation. Preferably, at least correction data for correcting the position of the actuator 22 are stored.

[0110] The throttle unit according to the invention makes it possible to set and adjust the throttle automatically in an accurate but nevertheless cost-effective manner.