Operating method

Abstract

The invention relates to a method for operating a device (10) for conveying viscous material to an applicator, the device comprising a conveying cylinder (12) in which a double-acting conveying piston (14) is movable back and forth, wherein: the conveying cylinder (12) has a first and a second chamber (16, 18) which are separated from one another by the conveying piston (14); each of the chambers (16, 18) has a material inlet (20) and a material outlet (22); the material inlets (20) are interconnected by means of an inlet-side material line (28), and the material outlets (22) are interconnected by means of an outlet-side material line (30); the inlet-side material line (28) is connected to a conveying pump for the material; the outlet-side material line (30) is connected to the applicator; each material inlet (20) is equipped with an inlet valve (24) for closing and opening up the particular material inlet (20); and each material outlet (22) is equipped with an outlet valve (26) for closing and opening the particular material outlet (22). According to the invention, in order to set a predefined filling quantity in a selected chamber (16), either both inlet valves (24) are opened and both outlet valves (26) are closed, or both outlet valves (26) are opened and both inlet valves (24) are closed, and the conveying piston (14) is moved under force in order to enlarge the selected chamber (16) and reduce the size of the other chamber (18), and material is displaced from the other chamber (18) into the selected chamber (16).

Description

[0001]

[0002] August 13, 2025

[0003] Atlas Copco IAS GmbH, Gewerbestraße 52, 75015 Bretten

[0004] Operating procedures

[0005] The invention relates to a method for operating a device for conveying viscous material to an applicator according to the preamble of claim 1.

[0006] Devices for conveying viscous materials are primarily used in industrial manufacturing, particularly in the automotive industry, where workpieces are coated with viscous materials such as adhesives, sealants, insulating materials, or thermal paste. These devices convey the viscous material to an applicator, which applies it to the workpiece. Application often occurs as a continuous bead of material, a sequence of short beads and / or dots, or as a continuous coating. It is advantageous if the entire bead, coating, or sequence of beads and / or dots is applied in a single operation without interrupting the relative movement between the applicator and the workpiece.For this purpose, sufficient viscous material must be kept on hand, for example in a piston dispenser, which is filled with the required minimum quantity of viscous material before the start of the material application. Conveying devices, the operating method of which is the subject of the present invention, and which have a conveying cylinder with a double-acting conveying piston, as described, for example, in DE 10 2022 118228 A1, allow for a virtually continuous conveying of the viscous material to the applicator, since one chamber is always being emptied while conveying the material to the applicator and the other chamber is simultaneously being refilled. However, the short dead times during the reversal of the conveying piston's movement can also be problematic in some cases.

[0007] P 60832 / PCT

[0008] August 13, 2025 In some applications, the duration may be too long to ensure sufficiently continuous material flow.

[0009] It is therefore an object of the invention to further develop a method of the type mentioned at the outset in such a way that it enables a more continuous application of material.

[0010] This problem is solved according to the invention by a method having the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

[0011] The invention is based on the idea of ​​providing a sufficient fill level or quantity for a predetermined material application in one of the chambers by transferring material from the other chamber into a selected chamber before the application begins. For this purpose, the conveying piston is subjected to force to enlarge the selected chamber and reduce the size of the other chamber, displacing the material from the other chamber into the selected chamber. This transfer can be carried out either via the inlet valves, which are opened for this purpose while the outlet valves are closed, or via the outlet valves, which are opened for this purpose while the inlet valves are closed.Opening both the inlet and outlet valves simultaneously for transferring the material would be disadvantageous, as this would result in a high material pressure at the applicator, often determined by a feed pump, which in some applications cannot be sufficiently reduced, particularly when a long connecting line leads to the applicator. The method according to the invention allows the selected chamber to be filled with a sufficient quantity of material for the subsequent predetermined application without the material in the other chamber being lost. Instead, it is transferred to the selected chamber.

[0012] The delivery piston is conveniently moved by means of a motor acting on a piston rod protruding from the delivery cylinder. Before setting the predetermined fill quantity, a connecting line is conveniently installed between the

[0013] P 60832 / PCT

[0014] On August 13, 2025, the outlet-side material line and the applicator were blocked. This ensures that material from the other chamber is transferred to the selected chamber and does not reach the applicator.

[0015] The chamber with the larger fill level before the conveying piston moves can be selected. For this purpose, the fill level of the chamber is determined before the piston moves. The chamber with the larger fill level is generally filled more quickly to the predetermined level. It goes without saying that no redistribution occurs if at least one of the chambers already contains the predetermined level or more. Alternatively, the chambers can be selected alternately, so that the material is applied alternately from one chamber and then the other. In this case, a prior determination of the fill level of the chambers is not necessary. Furthermore, the chambers are loaded evenly during operation.

[0016] Before setting the specified fill quantity, it is advisable to determine the operating state of the device. Depending on this state, either the inlet or outlet valves are then opened to adjust the fill quantity. To determine the operating state, the material pressure at the material outlets and / or the material inlets can be measured. Since the material pressure at the material inlets, which are usually connected to a feed pump, is generally significantly higher than at the material outlets, which are connected to the applicator, transferring the material via the inlet valves carries a lower risk of air inclusions that could adversely affect the material.Before the next material application begins, the pressure in the selected chamber must be reduced, as it is usually higher than the desired pre-pressure at which the material is conveyed to the applicator. This is generally achieved through a pressure release process in which a small amount of material is discharged from the selected chamber. If the inlet valves are opened to set the specified fill quantity, it is advisable to adjust the pressure after the specified fill quantity has been set.

[0017] P 60832 / PCT

[0018] On August 13, 2025, material was removed from the selected chamber at a predetermined pressure, a pressure reduction process that is time-consuming. On the other hand, when transferring material via the outlet valves, it must be noted that this is only possible if a sufficiently high material pressure exists in the chambers. If this pressure is present, transferring material via the outlet valves may be preferable, as the conveying device then does not need to be brought back into an operational state by the pressure reduction process described above and is therefore ready for operation again more quickly. It is therefore preferred that, to set the predetermined fill quantity, the inlet valves are opened when the material pressure at at least one of the material outlets falls below a first minimum value.Furthermore, it is advantageous that the outlet valves are opened to set the predetermined fill quantity when the material pressure at both material outlets exceeds a second minimum value. This second minimum value can be equal to or greater than the first minimum value.

[0019] Finally, parameters can be used to determine the operating state, defining when the applicator should apply material to a workpiece. To set the specified fill quantity, the inlet valves are opened when the material application is at least a predetermined time in the future. The transfer of material via the inlet valves then always occurs when there is sufficient time after the transfer and before the next material application for the pressure reduction process described above.

[0020] The invention will now be explained in more detail with reference to an exemplary embodiment shown schematically in the drawing. It shows

[0021] Fig. 1 shows a device for conveying viscous material.

[0022] The device 10 for conveying viscous material, or conveying device 10 for short, shown in the drawing, has a conveying cylinder 12 in which a conveying piston 14 is movable back and forth. The conveying cylinder 12 has a first chamber 16 and a second chamber 18, which are separated by the conveying piston 14.

[0023] P 60832 / PCT

[0024] The chambers 16 and 18 are sealed and separated from each other. Each chamber has a material inlet 20 and a material outlet 22, with each material inlet 20 being equipped with an inlet valve 24 for closing and opening, while each material outlet 22 is equipped with an outlet valve 26 for closing and opening. The two material inlets 20 are connected to each other by an inlet-side material line 28, while the two material outlets 22 are connected to each other by an outlet-side material line 30. A supply line 32 from a feed pump (not shown) opens into the inlet-side material line 28, while a connecting line 34 to an applicator (not shown) branches off from the outlet-side material line 30.

[0025] During operation of the conveying device 10, material is alternately conveyed from the first chamber 16 and the second chamber 18 to the applicator via the respective material outlet 22, the outlet-side material line 30, and the connecting line 34 to apply a viscous material to workpieces. Simultaneously, material is introduced into the other chamber 16, 18, from the conveying pump via the supply line 32, the inlet-side material line 28, and the respective material inlet 20. To convey material from the first chamber 16, the inlet valve 24 of the second chamber 18 and the outlet valve 26 of the first chamber 16 are opened, while the inlet valve 24 of the first chamber 16 and the outlet valve 26 of the second chamber 18 are closed.When material is conveyed from the second chamber 18, the inlet valve 24 of the first chamber 16 and the outlet valve 26 of the second chamber 18 are opened, while the inlet valve 24 of the second chamber 18 and the outlet valve 26 of the first chamber 16 are closed. The conveying piston 14 is moved primarily due to the pressure generated by the conveying pump, which in most cases is significantly higher than the pre-pressure applied to the applicator. In this way, almost continuous conveying of the material can be achieved by reversing the direction of movement of the conveying piston 24 by switching the inlet and outlet valves 24 and 26 as soon as one of the chambers 16 and 18 is emptied. The conveying of the material can be stopped after such a reversal.

[0026] P 60832 / PCT

[0027] On August 13, 2025, switching will resume after a dead time that is regularly significantly shorter than one second.

[0028] In some applications, however, such a dead time is too long. Such applications arise, for example, when a continuous bead of material must be applied to a workpiece in a single operation by moving the applicator along an application path relative to the workpiece using an industrial robot. In such a case, it may be necessary to fill one of the two chambers 16, 18 with a quantity of the viscous material sufficient to apply the bead of material completely and without interruption to the workpiece. For this purpose, the fill quantity of the two chambers 16, 18 is first determined. Since the chambers 16, 18 are always completely filled with the viscous material, the fill quantity they contain can be easily calculated by determining the position of the conveying piston 14.This is performed by an evaluation unit (not shown in the drawing), which receives position data, for example, from an increment counter of the motor. If one of the chambers 16, 18 already contains the specified fill quantity, it is selected for the discharge of the viscous material to the applicator, and the conveying piston 14 is moved, after opening the corresponding inlet and outlet valves 24, 26, so that the respective chamber 16, 18 decreases in size. If neither of the two chambers 16, 18 contains at least the specified fill quantity, material is transferred from one chamber to the other. For this purpose, one of the chambers 16, 18, in this case the first chamber 16, is selected and subsequently referred to as the selected chamber. The selected chamber is generally the chamber 16, 18 that initially contains the larger fill quantity. To transfer the material, either both inlet valves 24 or both outlet valves 26 are opened.When the inlet valves 24 are opened, the outlet valves 26 remain closed, and vice versa. Subsequently, the conveying piston 14 is moved by means of a motor 36, which is connected to it via a piston rod 38, such that the selected chamber 16 enlarges and the other chamber 18 shrinks, so that material is conveyed either via the inlet-side material line 28 or via the outlet-side material line.

[0029] P 60832 / PCT

[0030] 13 August 2025 30 from the other chamber 18 into the selected chamber 16, until the latter contains at least the specified fill quantity.

[0031] Whether the inlet valves 24 or the outlet valves 26 are opened for transfer depends on the operating state of the conveying device 10. It is generally preferred to open the inlet valves 24 for transfer and keep the outlet valves 26 closed, since the material pressure is usually higher on the inlet side than on the outlet side, and the risk of a loss of contact between the material and the conveying piston 14 in the other chamber is then lower. Such a loss of contact can allow air to enter the chamber in question, often rendering the material unusable. However, if the transfer is achieved by opening the inlet valves 24, the material pressure in both chambers 16 and 18 is usually too high after the transfer is complete, so that material must be drained from the selected chamber to reduce the pressure. Such a pressure reduction process is time-consuming.Furthermore, while re-transferring the material by opening the outlet valves 26 is advantageous in terms of saving time, as the time-consuming pressure reduction process after re-transferring is eliminated, the material pressure at the outlet is often not high enough to ensure reliable re-transferring without loss of contact between the material and the conveying piston 14. For this purpose, pressure sensors 40 are provided, which measure the pressure at the material inlets 20 and the material outlets 22 between the chambers 16, 18 and the valves 24, 26, and transmit these measurements to the evaluation unit. The evaluation unit analyzes the received data and then determines whether the inlet valves 24 or the outlet valves 26 should be opened for re-transferring. Finally, the evaluation unit also receives signals from the robot carrying the applicator, indicating whether the application process is active or inactive.The application process is active when an application is scheduled within a predefined time period. In such a case, the evaluation unit recognizes that the time between the transfer and the planned start of the application is insufficient to carry out a pressure reduction process and opens the outlet valves 26 for the transfer, provided the material pressure present there is sufficient.

[0032] P 60832 / PCT

[0033] August 13, 2025. During the transfer process, the connecting line 34 remains closed at all times. A further pressure sensor 42 measures the material pressure in the connecting line and also transmits its readings to the evaluation unit.

[0034] In summary, the following can be stated: The invention relates to a method for operating a device 10 for conveying viscous material to an applicator, which has a conveying cylinder 12 in which a double-acting conveying piston 14 is movable back and forth, wherein the conveying cylinder 12 has a first and a second chamber 16, 18, which are separated from each other by the conveying piston 14, wherein each of the chambers 16, 18 has a material inlet 20 and a material outlet 22, wherein the material inlets 20 are connected to each other by means of an inlet-side material line 28 and the material outlets 22 are connected to each other by means of an outlet-side material line 30, wherein the inlet-side material line 28 is connected to a conveying pump for the material, and wherein the outlet-side material line 30 is connected to the applicator.wherein each material inlet 20 is provided with an inlet valve 24 for closing and opening the respective material inlet 20 and wherein each material outlet 22 is provided with an outlet valve 26 for closing and opening the respective material outlet 22. According to the invention, it is provided that, in order to set a predetermined fill quantity of a selected chamber 16, either both inlet valves 24 are opened and both outlet valves 26 are closed, or both outlet valves 26 are opened and both inlet valves 24 are closed, and the conveying piston 14 is acted upon to enlarge the selected chamber 16 and reduce the size of the other chamber 18, and material is displaced from the other chamber 18 into the selected chamber 16.

[0035] P 60832 / PCT

[0036] August 13, 2025

Claims

9 Claims 1. Method for operating a device (10) for conveying viscous material to an applicator, the device comprising a conveying cylinder (12) in which a double-acting conveying piston (14) is movable back and forth, the conveying cylinder (12) comprising a first and a second chamber (16, 18) which are separated from each other by the conveying piston (14), each of the chambers (16, 18) comprising a material inlet (20) and a material outlet (22), the material inlets (20) being connected to each other by means of an inlet-side material line (28) and the material outlets (22) being connected to each other by means of an outlet-side material line (30), the inlet-side material line (28) being connected to a conveying pump for the material, and the outlet-side material line (30) being connected to the applicator.wherein each material inlet (20) is provided with an inlet valve (24) for closing and opening the respective material inlet (20) and wherein each material outlet (22) is provided with an outlet valve (26) for closing and opening the respective material outlet (22), characterized in that, to set a predetermined fill quantity of a selected chamber (16), either both inlet valves (24) are opened and both outlet valves (26) are closed, or both outlet valves (26) are opened and both inlet valves (24) are closed, and the conveying piston (14) is acted upon to enlarge the selected chamber (16) and reduce the size of the other chamber (18), and material is displaced from the other chamber (18) into the selected chamber (16). P 60832 / PCT August 13, 2025 2. Method according to claim 1, characterized in that the conveying piston (14) is moved by means of a motor (36) acting on a piston rod (38) projecting from the conveying cylinder (12).

3. Method according to claim 1 or 2, characterized in that before moving the conveying piston (14) the filling quantity of the chambers (16, 18) is determined and the chamber (16, 18) with the larger filling quantity is selected.

4. Method according to claim 1 or 2, characterized in that the chambers (16, 18) are selected alternately.

5. Method according to one of the preceding claims, characterized in that a connecting line (34) between the outlet-side material line (30) and the applicator is blocked before the predetermined fill quantity is set.

6. Method according to one of the preceding claims, characterized in that an operating state of the device (10) is determined before the predetermined filling quantity is set and that, depending on the operating state, either the inlet valves (24) or the outlet valves (26) are opened to set the predetermined filling quantity.

7. Method according to claim 6, characterized in that the material pressure is measured at the material outlets (22) and / or at the material inlets (20) to determine the operating state.

8. Method according to claim 7, characterized in that the inlet valves (24) are opened to adjust the predetermined fill quantity when the material pressure at at least one of the material outlets (22) falls below a first minimum value.

9. Method according to claim 7 or 8, characterized in that the outlet valves (26) are opened to adjust the predetermined fill quantity. P 60832 / PCT August 13, 2025 11 will occur if the material pressure at both material outlets (22) exceeds a second minimum value.

10. Method according to one of claims 6 to 9, characterized in that parameters are used to determine the operating state which define when material application by the applicator is to take place on a workpiece, and that the inlet valves (24) are opened to set the predetermined fill quantity when the material application is at least a predetermined time interval in the future.

11. Method according to one of the preceding claims, characterized in that the inlet valves (24) are opened to adjust the predetermined fill quantity and that, after adjusting the predetermined fill quantity, material is removed from the selected chamber (16) to adjust a predetermined material pre-pressure. P 60832 / PCT August 13, 2025

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