Metering system

Abstract

A metering system for applying a bead of a multi-component composite material to a component. The metering system comprises a mixing head including a mixing chamber. The metering system includes one supply line for each component of a multi-component composite material, leading from a source of each component to the mixing chamber. The mixing chamber is configured to mix the components of the multi-component composite material in the mixing chamber and has an outlet opening through which the mixed multi-component composite material exits the mixing head. The metering system includes a metering pump to convey a discharge of the multi-component composite material through the outlet opening. The metering system includes a control unit to output, to the metering pump, a control signal comprising control information and adjust a metering output of the multi-component composite material through the outlet opening of the mixing head based on the control signal.

Claims

1. A metering system for applying a bead of a multi-component composite material to a component, comprising: a mixing head, comprising: a mixing chamber; a first supply line for supplying a first component of the multi-component composite material from a source container of the first component to the mixing chamber; a second supply line for supplying a second component of the multi-component composite material from a source container of the second component to the mixing chamber; wherein the mixing chamber is configured to mix the first component and the second component of the multi-component composite material to form a mixed multi-component composite material comprising an adhesive foam or sealing foam in the mixing chamber; and an outlet opening through which the mixed multi-component composite material exits the mixing head; a first metering pump connected to the first supply line and arranged at a maximum distance of 2 m from the outlet opening of the mixing head, wherein the first metering pump is configured to control the introduction of the first component of the multi-component composite material into the mixing chamber; a second metering pump connected to the second supply line and arranged at a maximum distance of 2 m from the outlet opening of the mixing head, wherein the second metering pump is configured to control the introduction of the second component of the multi-component composite material into the mixing chamber, wherein the introduction of the first component and the second component into the mixing chamber causes a discharge of the mixed multi-component composite material through the outlet opening of the mixing head; a drive configured to move the outlet opening along a trajectory based on trajectory information received from a drive controller, wherein the trajectory information relates to the trajectory and a path velocity based on the trajectory; a control unit configured to output, to the first metering pump and the second metering pump, control signals comprising control information that causes first metering pump and the second metering pump to adjust metering outputs of the first component and the second component of the multi-component composite material, wherein the control unit is configured to receive, from the drive controller, the trajectory information, and to output, for each portion of the trajectory to which a different path velocity is allocated compared with at least one directly adjacent portion of the trajectory, first control information to the first metering pump a predetermined time period prior to outputting second control information to the second metering pump so that a cross-sectional area of the bead of the mixed multi-component composite material remains substantially constant over an entirety of the trajectory; a first supply pump connected to the first supply line and arranged adjacently to the source container of the first component; and a second supply pump connected to the second supply line and arranged adjacently to the source container of the second component.

2. The metering system of claim 1, wherein the control unit is configured to output, for each trajectory portion having a uniform path velocity, separate control information to the first metering pump and the second metering pump in separate control signals.

3. The metering system of claim 1, wherein the trajectory, which comprises different path velocities, is formed as a closed ring.

4. The metering system of claim 1, wherein the metering system is configured to discharge the mixed multi-component composite material in an output range of from 0.1 cm.sup.3/s to 20 cm.sup.3/s.

5. The metering system of claim 1, wherein the control unit is further configured to assign, to related portions of the trajectory that have a consistent curvature, one or more of a uniform path velocity or uniform control information for the first metering pump and the second metering pump to adjust the discharge of the mixed multi-component composite material.

6. The metering system of claim 1, wherein the control unit is configured to output to the first metering pump and the second metering pump a plurality of pieces of control information, separated for each trajectory portion having a uniform path velocity, together in at least one control signal.

7. The metering system of claim 1, wherein the outlet opening of the mixing head is formed as a portion of the mixing chamber or is connected to the mixing chamber by means of a line.

8. The metering system of claim 7, wherein the outlet opening of the mixing head is connected to the mixing chamber by means of the line, and wherein the line is formed between the outlet opening and the mixing chamber of the mixing head as a tubular outflow nozzle or a hose line.

9. The metering system of claim 1, wherein the metering system is configured to move the outlet opening for applying the mixed multi-component composite material at a speed of from 1 m/min to 100 m/min.

10. The metering system of claim 9, wherein the metering system is configured to move the outlet opening for applying the mixed multi-component composite material at a speed of from 3 m/min to 60 m/min.

11. A method for applying a bead of a multi-component composite material to a component, comprising: providing a mixing chamber and a mixing head, the mixing head having a first supply line for supplying a first component of the multi-component composite material from a source container of the first component to the mixing chamber, and a second supply line for supplying a second component of the multi-component composite material from a source container of the second component to the mixing chamber, wherein the mixing head is configured to mix the first component and the second component of the multi-component composite material to form a mixed multi-component composite material comprising an adhesive foam or sealing foam in the mixing chamber, wherein the mixing head has an outlet opening through which the mixed multi-component composite material exits the mixing head; providing a first metering pump connected to the first supply line and arranged at a maximum distance of 2 m from the outlet opening of the mixing head wherein the first metering pump is configured to control the introduction of the first component of the multi-component composite material into the mixing chamber; providing a second metering pump connected to the second supply line and arranged at a maximum distance of 2 m from the outlet opening of the mixing head, wherein the second metering pump is configured to control the introduction of the second component of the multi-component composite material into the mixing chamber, wherein the introduction of the first component and the second component into the mixing chamber causes a discharge of the mixed multi-component composite material through the outlet opening of the mixing head; operating the movement of the outlet opening along a trajectory based on trajectory information received from a drive controller, wherein the trajectory information relates to the trajectory and a path velocity based on the trajectory; receiving at a control unit, the trajectory information; operating the control unit to output first control information to the first metering pump a predetermined time period prior to outputting second control information to the second metering pump, wherein the first control information causes the first metering pump to adjust metering outputs of the first component and the second control information causes the second metering pump to output the second component of the multi-component composite material, and wherein the control unit outputs, for each portion of the trajectory to which a different path velocity is allocated compared with at least one directly adjacent portion of the trajectory, separate first control information to the first metering pump and second control information to the second metering pump so that a cross-sectional area of the bead of the mixed multi-component composite material remains substantially constant over the entire trajectory, providing a first supply pump connected to the first supply line and arranged adjacently to the source container of the first component; and providing a second supply pump connected to the second supply line and arranged adjacently to the source container of the second component.

12. The method of claim 11, wherein the control unit outputs, for each trajectory portion having a uniform path velocity, separate control information to the first metering pump and the second metering pump in separate control signals.

13. The method of claim 11, wherein the mixed multi-component composite material is discharged in an output speed ranging from 0.1 cm.sup.3/s to 20 cm.sup.3/s.

14. The method of claim 11, wherein the control unit assigns, to related portions of the trajectory that have a consistent curvature, one or more of (a) a uniform path velocity or (b) uniform control information such that the first metering pump and the second metering pump operate to leave the discharge of the mixed multi-component composite material over each related portion unchanged.

15. The method of claim 11, wherein the control unit is configured to output to the first metering pump and the second metering pump a plurality of pieces of control information, separated for each trajectory portion having a uniform path velocity, together in at least one control signal.

16. The method of claim 11, wherein the outlet opening for applying the mixed multi-component composite material moves at a speed ranging from 1 m/min to 100 m/min.

17. The method of claim 16, wherein the outlet opening is configured to move at a speed ranging from 3 m/min to 60 m/min when applying the multi-component composite material.

Description

(1) The present invention will be described in greater detail below on the basis of an example embodiment. In the drawings:

(2) FIG. 1 is a side view of an embodiment of the device according to the invention;

(3) FIG. 2 is a plan view of the device from FIG. 1;

(4) FIGS. 3a to 3d are longitudinal sections through beads of a multi-component composite material.

(5) FIG. 4 is a plan view of the metering system according to the invention;

(6) FIG. 5 is a sectional side view of a dynamic mixing head of the metering system according to the invention; and

(7) FIG. 6 is a perspective view of a container frame of the device according to the invention.

(8) FIG. 1 denotes a metering system according to the invention in general terms by reference numeral 10. The metering system 10 comprises a mixing head 12, in which components of a multi-component composite material are mixed together in a mixing chamber 14. The multi-component composite material is applied to a component from the mixing head 12 through an outlet opening 16. In the example embodiment shown in FIG. 1, the outlet opening 16 is connected to the mixing chamber 14 by means of a tubular outflow nozzle 18.

(9) In the embodiment shown here, the components of the multi-component composite material are conveyed by means of four metering pumps 20, 22, 24, 26 from component sources (not shown) to the mixing chamber, and from there to the outlet opening 16. As described at the outset, however, it may also be conceivable to form a metering system 10 according to the invention having two or three metering pumps.

(10) A control unit 28 in data-communication with the metering pumps 20, 22, 24, 26 delivers control information to the metering pumps 20, 22, 24, 26, the respective metering outputs of the metering pumps 20, 22, 24, 26 being adjusted on the basis of said control information. In this case, the metering output can in particular be deemed to be the volume and/or mass conveyed per second by each metering pump 20, 22, 24, 26.

(11) In FIG. 2, the metering system 10 is viewed vertically from above and it can be seen that the outlet opening 16 (in FIG. 2 concealed by components above it) is moved along a trajectory 30, on which the multi-component composite material is to be applied to a component 32.

(12) In the process, the trajectory 30 comprises a first portion 30_1, which extends substantially in a straight line, a second portion 30_2, which has a 90 curvature, and a third portion 30_3, which again extends substantially in a straight line.

(13) A drive 34 is configured to move the outlet opening 16 along the trajectory 30. Since, like all drives, the drive 34 requires a certain amount of time or a certain distance in order to accelerate the outlet opening 16, it is obvious that higher movement speeds of the outlet opening 16 can be achieved in the first portion 30_1 and the third portion 30_3 of the trajectory 30 than in the second portion 30_2, in which the outlet opening 16 has to traverse the 90 curvature.

(14) Since the control unit 28 receives information, for example from a CNC control unit (not shown), related to the trajectory 30 and the path velocities of the outlet opening 16 that can be achieved therein by the drive 34, the control unit 28 can output, to the metering pumps 20, 22, 24, 26, control information related to a corresponding portion of the trajectory 30 in such a way that, despite varying path velocities of the outlet opening 16, the same amount of multi-component composite material is continually applied per unit of distance (for example when considered in each case over a path portion having a length of 5 cm).

(15) FIGS. 3a to 3d show longitudinal sections through beads 36, 38, 40, 42 of a multi-component composite material, the longitudinal sections having been taken, by way of example, along a plane that is substantially parallel to a page plane in FIG. 2. The arrows in FIGS. 3a to 3d indicate the direction in which the respective beads 36, 38, 40, 42 of multi-component composite material have been applied.

(16) In this context, FIG. 3a shows a bead 36 which has been produced using a conventional prior-art metering system. In other words, the bead 36 has been applied with a constant movement speed of an outlet opening and a constant metering output of a metering pump. The portions 36_1, 36_2 and 36_3 have a substantially uniform bead thickness.

(17) FIG. 3b comprehensibly illustrates the problem that occurs when a known metering system is modified merely to the extent that the outlet opening 16 is moved at a higher speed in straight portions of the trajectory 30 than in curved portions of the trajectory 30. The metering output of the metering system remains constant in the process. It can be seen in FIG. 3b that the thickness of the bead 38 initially increases in a region 38_1, in which the outlet opening 16 is decelerated in order to subsequently traverse the curved region 38_2, and then reaches the thickness that corresponds to the speed of the outlet opening 16 at which the portion 38_2 is traversed. In a portion 38_3, downstream of the curved portion 38_2, the outlet opening 16 is accelerated again such that the thickness of the bead 38 accordingly decreases again.

(18) FIG. 3c now shows another undesirable result of an application of a bead 40 of multi-component composite material to a component. During application of the bead 40, the speed at which the outlet opening 16 is moved is adapted on the basis of the curvatures of the portions 40_1, 40_2 and 40_3, but the metering output of a metering pump or of metering pumps 20, 22, 24, 26 is not controlled in proportion to the speed of the movement of the outlet opening 16. As a consequence, the metering pump either decelerates or accelerates too sharply, and so a thickness of the bead 40 decreases in the portion 40_1 towards the portion 40_2, increases again in the portion 40_2 towards the start of the portion 40_3, and then decreases again over the portion 40_3.

(19) FIG. 3d now shows the result of applying a bead 42 of a multi-component composite material on the basis of the present invention. When the bead 42 is applied, both a movement speed of the outlet opening 16 is varied, and a metering output of the metering pumps 20, 22, 24, 26 is controlled in proportion to the movement speed of the outlet opening 16. As a result, it is possible to generate a bead 42 that has a consistent thickness over the portions 42_1, 42_2 and 42_3, i.e. a cross-sectional area that is consistent in planes arranged at right angles to the page plane in FIG. 3d and at right angles to an application direction of the bead 42.

(20) FIG. 4 is a plan view of the metering system 10. In this case, the mixing head 12 is viewed from above, similarly to FIG. 2. On both sides of the mixing head 12, first and second metering pumps 22, 24 are arranged; in this case, by way of example, the first metering pump 22 is to be assigned to the first component A and the second metering pump 24 is to be assigned to the second component B.

(21) In the bottom right-hand region in FIG. 4, a first component container 44 of the first component A and a second component container 46 of the second component B can be seen; in this case these containers are in the form of drums and are interchangeably connected to the metering system 10. The component containers 44 and 46 are each fluidically coupled to a supply pump 48, 50; here, the supply pump 48 conveys the first component A from the first component container 44, and the supply pump 50 conveys the second component B from the second component container 46, to the mixing head 12 by means of lines (not shown). During an operating phase of the mixing head, the supply pumps 48, 50 are operated either continuously or in a speed-controlled manner, such that a supply of the components to the mixing head and maintenance of a predetermined overpressure in the supply lines remain guaranteed.

(22) In this case, the metering system 10 further comprises an air-conditioning apparatus 52, which is configured to control the temperature of, i.e. cool or heat, at least one of the components A and B.

(23) FIG. 4 also shows a flushing apparatus 54, for emptying and/or cleaning the mixing head 12, and scales 56.

(24) FIG. 5 is a sectional side view, on an enlarged scale, of the mixing head 12. It can be seen that in this embodiment the mixing head 12 is in the form of a dynamic mixing head. In other words, in the mixing chamber 14 there is a stirring element 58 that turns within the mixing chamber 14 about the vertical axis (an axis from the top downwards in FIG. 5).

(25) On its outer circumference, the stirring element 58 has recesses 60 for improving a stirring action of the stirring element 58. In this way, components introduced into the mixing chamber 14, for example components A and B, can be blended very homogeneously.

(26) The mixed components exit the mixing chamber 14 through the tubular outflow nozzle 18 and are then applied to a workpiece through the outlet opening 16.

(27) FIG. 6 shows a container frame 62, which is used, among other things, to receive the first component container (not shown) and second component container 46, the respective supply pumps 48, 50 and the air-conditioning apparatus 52. As can be seen, in this case the component containers are arranged above the supply pumps 48, 50, and so components A and B can be provided to the supply pumps 48, 50 in a gravity-assisted manner. In addition, the elevated arrangement of the component containers makes it simpler to swap them, for example by using a forklift truck.