DE202019000576U1 - Device for applying medium to high viscosity liquid materials - Google Patents

Abstract

Apparatus (10) for applying medium to highly viscous liquid materials comprising a pumping device (12), an application head (16) fluidically connected via a hose (14) to the pumping device (12) and a control unit (50)
the pump device (12) comprises a follower plate (22) with a scoop piston pump (24), the scoop piston pump (24) comprising a drive via which a movement speed of a delivery piston (25) of the scoop pump (24) can be regulated, and
the applicator head (16) comprises a valve (36) for releasing the flow of liquid material through the applicator head (16),
characterized in that between the pumping means (12) and the applicator head (16) is arranged a flow sensor (60) for measuring the flow of the liquid material and wherein the control unit (50) is arranged to contribute the measured value of the flow when applying the liquid material the regulation of the speed of movement of the delivery piston (25) of the pump piston pump (24) to be considered.

Description

The invention relates to a device for applying medium to highly viscous liquid materials, which comprises a pumping device and an applicator head, wherein the device is adapted to convey by the pumping device liquid material from a reservoir to the applicator head.

For example, in the automotive industry, a mixed construction is increasingly used in which different materials are combined. Multi-component adhesives are often used to join the various materials. Furthermore, sealants, lubricants and fillers are typically used in production. These adhesives, sealants, lubricants and fillers are usually pasty or medium and high viscosity materials and have a high viscosity. These medium or high viscosity materials are supplied to the production process with conveyors, the conveyors having a gun with a valve. The valve controls the flow of medium or high viscosity material. It is desirable to be able to set the flow exactly to a predetermined value.

Known dosing systems use pneumatically operated scoop pumps, which initially fill a piston-operated piston-operated doser, wherein the piston dosing device in turn applies the material to a workpiece or component. Other known conveyors use screw pumps, with which the amount of material conveyed and the delivery pressure can be set well. A disadvantage of the screw pumps is that the screw pumps are heated by friction and the material to be pumped can be damaged by the friction in its structure. In particular, it may lead to a destruction of the chemical structure of the material due to the high frictional forces. Therefore, it would be desirable to use scoop pumps in such a conveyor. With ladle pumps, however, there is the problem that the flow rate and the pressure of the position and speed of a delivery piston in the pump are dependent, so that they fluctuate. A uniform material delivery is required for a uniform material application. For this purpose, pressure fluctuations in the application head must be compensated by the conveyor.

Out EN 20 2017 106 256 U1 a device for conveying pasty media from at least two containers is known. The device comprises at least one scoop pump, which communicates with a follower plate and is operated by means of a drive. The drive is equipped with an electronic distance measurement. The electronic distance measurement allows extremely precise monitoring of the drive cylinder, so that an error message can occur with the slightest deviations from the preset path lengths. At the same time, the conveyed quantity of pasty media can be precisely determined by measuring the distance.

DE 20 2014 100 750 U1 discloses an apparatus for completely emptying storage containers containing liquid material. The device comprises a follower plate and a scoop pump. Furthermore, sensors in the form of linear transducers are provided which measure the height of the follower plate. In the case of delivery from several containers, due to the different compressibility of stock materials in the course of emptying the feed containers, deviations in the delivery quantity occur. These deviations are detected either via a measuring transducer and a driver corresponding to the transducer or via scales below the feed container and forwarded to the controller, wherein the controller continuously takes these deviations into account in the calculation of a pulse frequency for the drives of the pumps.

DE 10 2015 120 381 A1 describes a removal device with automatic delivery pressure control. A feed pump conveys material from containers to a mixing block. In the mixing block, a pressure sensor is provided which determines the delivery pressure. A control unit reads the pressure sensor and regulates a drive of the feed pump to set a target discharge pressure.

In the prior art, no conveyors are known which convey liquid material with a scoop pump and meter directly via a gun, with a uniform material application is guaranteed. Furthermore, it is disadvantageous in the known devices that there is no control of the amount of liquid dispensed with the applicator head.

A device is proposed for applying medium-viscosity to highly viscous liquid materials, which comprises a pumping device, an application head fluidically connected to the pumping device via a hose, and a control unit. The pump device comprises a follower plate with a scoop piston pump, the scoop pump comprising a drive, via which a movement speed of a delivery piston of the scoop pump can be regulated. The applicator head includes a valve for releasing the flow of liquid material through the applicator head. It is further provided that between the pumping device and the applicator head, a flow sensor for measuring the flow of the is arranged liquid material and that the control unit is adapted to take into account the measured value of the flow during the application of the liquid material in the regulation of the movement speed of the delivery piston of the pump piston.

The storage container is preferably a cylindrical drum. The storage container may include, for example, a pasty or medium to high viscosity liquid material such as an adhesive, lubricant, filler or sealant. Medium and high viscosity materials which can be applied by the proposed device include in particular adhesives, sealants, lubricants and fillers such as those used in the assembly of components in the automotive industry. In general, a medium-viscosity material is understood as meaning a material whose viscosity at 20 ° C. is greater than 50 Pa · s and less than or equal to 1000 Pa · s. High viscosity materials have a viscosity of more than 1000 Pa · s at 20 ° C.

The apparatus comprises a pumping device for conveying the liquid material from the reservoir to the applicator head. The pumping device comprises a follower plate with a pump. The pump of the pump device is designed according to the invention as a pump piston pump. In a scoop pump, a delivery piston is provided, which moves up and down in the pump. The delivery piston has an outlet valve, so that the liquid material to be pumped is conveyed on a downward movement of the delivery piston to the other side of the piston and liquid material is sucked out of the reservoir during an upward movement. The output side of the pump piston is connected via a hose to the gun.

The delivery piston of the pump is preferably driven by an electric drive, so that the movement speed of the delivery piston can be set quickly and precisely. In particular, the speed of movement of the electric drive can be regulated. For this purpose, the pump piston or its drive is connected to the control unit of the device. The drive is preferably designed as an electric drive with an electric motor. In particular, stepper motors and servomotors are suitable. For example, a three-phase motor is used whose speed is controlled. The control unit specifies the speed according to a regulation. A switching of a direction of the three-phase motor can be done for example via limit switches in a lifting unit of the pump piston pump. The electric drive may include sensors for determining a position and / or speed of the motor shaft. Furthermore, a sensor for detecting the position of the delivery piston can be provided.

The applicator head has a valve with which the delivery of the liquid material can be controlled. To apply liquid material, the valve is opened and the valve is closed again to stop the application. The amount of liquid material which is dispensed by the applicator head when the valve is open is preferably predetermined by the pump and thus regulated by regulating the speed of the delivery piston. The valve is preferably connected to the control unit so that it can be opened and closed by the control unit. In further embodiments, it may be provided that the valve in addition to a fully open position and a fully closed position also allows intermediate positions to influence the amount of material to be applied. Suitable valves include, for example, needle valves and rotary valves. An applicator head with a suitable rotary valve is for example in the utility model DE 20 2017 000 784 described.

The control unit of the device is preferably arranged to control the speed of the delivery piston, depending on a predetermined desired value for the flow of the liquid material through the open valve of the application head. An actual flow is measured via the flow sensor and transmitted to the control unit. Accordingly, the flow sensor is connected to the control unit and the control unit is set up to take into account the measured value for the flow in the regulation of the speed of the delivery piston.

A controller of the device preferably controls the flow in such a way that the speed of movement of the delivery piston of the delivery pump is regulated as an input variable as a function of the measured flow. If a change in the flow rate is detected, the speed of the delivery piston is adapted accordingly to the delivery piston pump. Preferably, the speed is increased when the flow rate is below a predetermined flow rate set point and, preferably, the velocity is decreased when the flow rate is above the set point.

Preferably, the flow sensor is designed as a flow sensor, which does not touch the liquid material. A preferred example of such a flow sensor is an ultrasound-based flow sensor.

Such flow sensors determine the flow through a pipe or a hose, by passing ultrasonic signals through the tube and collecting them again. In one embodiment of such a flow sensor, two ultrasonic sensors, each capable of transmitting and receiving ultrasonic signals, are slanted with respect to the pipe with respect to the flow direction of the liquid material in the pipe. Both ultrasonic sensors send out an ultrasonic signal for measuring the flow, which is received again by the respective other ultrasonic sensor. The transit time of the ultrasonic signals is measured in each case. The transit time of the ultrasonic signals is influenced by the flow rate of the liquid material in the interior of the tube, so that the flow rate can be determined from the measured signal propagation times. Based on the specific flow rate and the known cross-section of the tube, the flow can then be calculated, ie how much liquid material flows through the tube per unit of time. The tube may also be a tube, wherein the flow sensor is arranged in a fixed relation to the tube.

The flow sensor is preferably accommodated in a measuring module. The measuring module preferably comprises a pipe section with a defined cross section, wherein the flow sensor is fixed with respect to the pipe section in the measuring module. The measuring module also preferably has connections with which the measuring module can be connected to other parts of the device.

The measuring module is preferably arranged adjacent to the application head. By placing the measuring module as close as possible to the application head, possible disturbances which could influence the measurement result are avoided. In particular, influences are reduced by the pumping device. Preferably, it is provided that the measuring module has a first connection, which is connectable to an inlet of the application head, and has a second connection, which is connectable to the hose, which is in communication with the pumping device of the device. Furthermore, it is conceivable to arrange the measuring module around the hose which connects the pumping device to the application head. In this case too, it is preferable for the measuring module to be arranged as close as possible to the application head.

Preferably, the device is further adapted to measure the pressure of the liquid material and to take into account in the regulation of the drive of the scoop piston pump. For this purpose, the pump device preferably comprises a first pressure sensor, which is arranged on an outlet side of the scoop pump and is adapted to detect the pressure with which the scoop piston pump presses the liquid material into the hose. Preferably, the applicator head comprises a second pressure sensor, which is arranged on a supply side of the valve. The control unit is preferably set up to take into account the measured values of the first pressure sensor and / or of the second pressure sensor in the regulation of the movement speed of the delivery piston. In particular, it is preferred to regulate the movement speed such that the pressure at the supply side of the valve remains within a predetermined pressure range.

Preferably, in the regulation of the movement speed of the delivery piston, the measured value of the flow sensor is used in the first place, the regulation being regulated to a predetermined desired flow rate. The measured values of the first and / or of the second pressure sensor are preferably used in order to maintain the pressure within predetermined limits during regulation to the set flow rate. In particular, it is provided to specify a maximum pressure which may not be exceeded in the control of the predetermined target flow rate. If the pressure is above or below the predetermined pressure range, the speed of movement of the delivery piston is preferably adjusted such that the pressure returns to the predetermined range. It is accepted that when exceeding a maximum predetermined pressure and / or falls below a minimum predetermined pressure, the target flow rate is not reached for a short time.

In addition, the measured values of the first pressure sensor and / or of the second pressure sensor are preferably used to control the movement speed of the delivery piston if, for example due to a technical defect or a non-availability of measured values of the flow sensor, no measured values for the actual flow are available , In this case, the movement speed of the delivery piston of the scoop pump is preferably regulated in such a way that a predetermined desired pressure is achieved at the first pressure sensor and / or at the second pressure sensor.

Preferably, the control unit is further configured to perform a check of the device using the first and / or the second pressure sensor. If the predetermined pressure range is undershot, a leak in the system is preferably closed, through which liquid material emerges. If the predetermined pressure range is exceeded, blockage in the system is preferably concluded. In addition, the control unit is preferably set up when countermeasures are detected to initiate such as issuing an error message or switching off the pump piston. Preferably, these countermeasures are then initiated, even if a change in the speed of movement of the delivery piston of the scoop pump no normalization of the pressure in the predetermined pressure range within a predetermined period of time can be achieved.

For a controlled and uniform application of the liquid material to a component or workpiece, it is preferable to regulate the pressure of the liquid material in the gun so that it corresponds to a predetermined desired value or within a predetermined pressure range, since the flow, so the Amount of liquid material delivered in a time unit by the applicator, is dependent on the pressure. The desired value for the pressure on the supply side of the valve is preferably in the range from 5 to 250 bar, particularly preferably in the range from 30 to 150 bar.

When controlling the pressure to a desired value, a regulator of the device is preferably used, which preferably controls the pressure such that the movement speed of the delivery piston of the feed pump is controlled as an input variable in dependence of the measured on the supply side of the valve pressure. Upon a detected change in pressure, the speed of the delivery piston of the pump piston is adjusted accordingly. Preferably, the speed is increased when the pressure on the supply side of the valve is below the target pressure, and preferably the speed is lowered when the pressure on the supply side of the valve is above the target pressure. Accordingly, when specifying a pressure range, the speed of the delivery piston, for example, initially regulated only dependent on the measured flow rate and only then deviated from when a measured pressure is outside the predetermined pressure range. Then, the speed is lowered when the predetermined maximum pressure is exceeded and increases the speed when the predetermined minimum pressure is exceeded.

For the control as a function of the measured flow and / or as a function of the measured pressures, a controller is preferably used, which may for example be integrated into the control unit. Continuous controllers or unsteady controllers can be used as controllers. The control is preferably configured as a PID controller (proportional-integral-derivative controller), as a PI controller (proportional-integral controller) or as a PD controller (proportional-differential controller). Other forms of control such as a two-position controller are possible. In the control, a hysteresis can be provided, so that an intervention by the control only takes place when the absolute value of the deviation from the measured flow is greater than a predetermined deviation. A hysteresis can also be used when taking into account the measured pressure, so that an intervention by the control takes place only when the absolute value of the deviation from the measured pressure on the supply side of the valve from the target pressure is greater than a predetermined deviation. The predetermined deviation is, for example, 1 bar. Furthermore, it is preferable to design the control such that a delay between the measurement of a pressure change and / or a flow change and a change in the speed of the delivery piston is a maximum of 200 ms and preferably a maximum of 100 ms.

In the control, in each case a movement speed for the delivery piston is determined as a function of the control variables, that is to say of the measured flow or the measured pressures. To implement a change in the speed of movement of the delivery piston, a speed of the drive of the delivery piston pump is adjusted accordingly.

In the regulation of the flow rate to the desired value and / or the regulation of the pressure within the predetermined pressure range, a pressure difference between the pressure with which the pump piston pumps the liquid material into the hose and the pressure on the supply side of the valve is preferably taken into account. It is preferred in the regulation of the pressure, that in a deviation of the pressure on the supply side of the valve from the target pressure, a change in the speed of the delivery piston is made stronger, the greater the absolute value of the pressure difference between the pressure at which the pump piston the liquid Material presses into the hose, and the pressure on the supply side of the valve is.

Preferably, a time delay is determined which elapses after detection of a change in pressure measured by the first or second pressure sensor until this pressure change has transmitted via the hose and is also measured by the respective other pressure sensor, wherein the determined time delay in the regulation of the flow and / or the pressure within the given pressure range is used. In the regulation of the flow, it is particularly preferred, in an anticipated by a change in the desired flow pressure change the pump piston pump to anticipate to compensate for the determined time delay.

This can in particular an aging of a hose, which the pumping device and the order header connects, be balanced. With increasing aging, the hoses used receive more of the liquid material (for example, an adhesive), so that without taking into account the time delay, a reaction time between the pressure build-up of the pump and the actual pressure increase in the gun is getting longer. This is advantageously compensated by determining the time delay and corresponding anticipatory actuation of the pump by the appropriately set up control unit.

The determined time delay is preferably used in the control to specify the strength of a speed change of the delivery piston. This ensures that the system is not understeered or overridden in the control.

The amount of liquid material delivered by the scooping piston depends on the position of the scooping piston. Therefore, the control unit is preferably configured to increase the speed of a drive of the delivery piston before reaching a reversal point and to lower again after passing the reversal point. For this purpose, it may be provided to determine the position of the delivery piston via a sensor.

Preferably, the device comprises a positioning device, with which the application head can be moved relative to a component or workpiece. The positioning device is preferably configured such that movements in all three spatial directions are possible. Furthermore, it is preferred if the application head can also be rotated relative to the component or workpiece, wherein in turn a possibility for rotation about all three spatial directions is preferred. In the embodiment of the positioning device, it is possible that the application head is moved while the component or the workpiece is at rest or vice versa, that the application head rests and the component or the workpiece is moved. Mixed forms are also conceivable in which, for example, the component is displaceably arranged in two directions and a movement takes place in the remaining spatial direction as well as a rotation through the application head.

Preferably, the positioning device is implemented as a robot arm carrying the application head and arranged to move the application head relative to a stationary component.

The application head, together with the positioning device, can in particular be part of an application device used in a production process.

Preferably, the pumping device comprises a lifting device for raising and / or lowering the follower plate, wherein the lifting device has a controllable drive. The drive is preferably used in conjunction with the control of the pump piston, wherein the follower plate is lowered depending on the amount of withdrawn from the reservoir liquid material.

The valve of the application head is opened when liquid material is to be dispensed and is closed again after finishing the material application. In this way, running or dripping of liquid material is prevented. Preferably, the valve is a needle valve or a rotary valve.

list of figures

• 1 eine schematische Darstellung einer Vorrichtung zum Auftragen mittel- bis hochviskoser flüssiger Materialien und
• 2 eine schematische Darstellung eines Messmoduls.

An embodiment of the invention is illustrated in the drawings and explained in more detail in the following description. Show it:

• 1 a schematic representation of an apparatus for applying medium to high viscosity liquid materials and
• 2 a schematic representation of a measuring module.

The figures illustrate the subject matter of the invention only schematically.

1 shows a device 10 for applying medium to high viscosity liquid materials. The device 10 includes a pumping device 12 and an order header 16 , which has a hose 14 connected to each other.

The pumping device 12 includes a base plate 18 on which a storage container 20 is turned off. In the illustrated situation, the reservoir is 20 executed as a barrel. The pumping device 12 further includes a follower plate 22 with a piston pump 24 that of a lifting device 19 be worn. With the lifting device 19 can the follower plate 22 in the storage container 20 lowered and raised again.

The piston pump 24 has a delivery piston 25 up, that of a drive 26 via a screw jack 27 is driven. The drive 26 is designed for example as an electric motor.

The order header 16 has a feeder 34 on which over the hose 14 with the through the piston pump 24 subsidized material is supplied. On the hose 14 is a measuring module 70 arranged, which has a flow sensor 60 includes. The flow sensor 60 is set up, the flow of liquid material from the pumping device 12 to the order header 16 to eat. The flow sensor 60 is with a control unit 50 connected. About a valve 36 , which is designed for example as a needle valve, may be a nozzle 38 closed or opened.

The order header 16 is from a positioning device 44 worn, which is designed for example as a robot arm. The positioning device 44 allows the order header 16 relative to a component 46 to move.

At a pump outlet 28 the scoop pump 24 is a first pressure sensor 30 arranged, which the pressure of the liquid material in front of the hose 14 certainly. In the feeder 34 of the order header 16 is a second pressure sensor 32 arranged, which the pressure of the liquid material in the gun 16 in front of the valve 36 certainly. The first pressure sensor 30 and the second pressure sensor 32 are each with the control unit 50 connected. The control unit 50 also stands with the drive 26 the scoop pump 24 in connection.

To apply liquid material, the valve 36 open, so that from the piston pump 24 conveyed liquid material from the nozzle 38 can escape. The flow, that is, the amount of liquid material which is conveyed per unit time, is via the flow sensor 60 of the measuring module 70 determined and to the control unit 50 transmitted. The control unit 50 then regulates the drive 26 such that the flow rate is regulated to a predetermined desired value.

For targeted and correct amount of liquid material on the component 46 Apply, is preferably additionally provided, the pressure in the gun 16 to monitor that it is within a predetermined pressure range. The control unit detects this 50 the pressure in the gun 16 and on the output side of the scoop pump 24 , The control unit 50 then regulates the speed of the drive 26 and thus the speed of the delivery piston 25 the scoop pump 24 initially such that the with the flow sensor 60 measured value corresponds as possible to a predetermined target value for the flow. Exceeds or falls below by the second pressure sensor 32 in front of the valve 36 measured pressure the predetermined pressure range, then the movement speed of the delivery piston is correspondingly 25 changed, for which a short-term deviation from the predetermined target flow rate is accepted.

For applying the liquid material to the component 46 then becomes the order header 16 using the positioning device 44 relative to the component 46 moves, with the valve 36 is selectively opened and closed.

2 shows a schematic representation of the measuring module 70 , which is between the pumping device 12 and the order header 16 the device 10 is arranged, compare 1 ,

The measuring module 70 includes a pipe section 72 as well as the flow sensor 60 , The flow sensor 60 includes two ultrasonic sensors 62 , which in each case ultrasound signals 64 can send and receive. The ultrasonic sensors 62 , are related to the pipe section 72 or with reference to the direction of a flow 74 of the liquid material in the pipe section 72 arranged at an angle. Both ultrasonic sensors 62 send to measure the flow 74 one ultrasonic signal each 64 from which of the other ultrasonic sensor 62 is received again. The duration of the ultrasonic signals 64 is measured in each case. The duration of the ultrasonic signals 64 is determined by the flow rate of the liquid material in the interior of the pipe section 72 influenced, so that the flow rate can be determined from the measured signal transit times. Based on the specific flow rate and the known cross section of the pipe section 72 then can the flow 74 calculated, so how much liquid material per unit time through the pipe section 72 flows. Alternatively to a separate pipe section 72 can be provided that the hose 14 , which the pumping device 12 with the order header 16 connects, through the measuring module 70 is guided, wherein a portion of the hose 15 as a pipe section 72 is used.

The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

LIST OF REFERENCE NUMBERS

10

contraption

12

pumping device

14

tube

18

baseplate

19

lifting device

20

reservoir

22

follower plate

24

Priming piston pump

25

delivery piston

26

drive

27

screw jack

28

pump output

30

first pressure sensor

32

second pressure sensor

34

supply

36

Valve

38

jet

44

positioning

46

component

50

control unit

60

Flow Sensor

62

ultrasonic sensor

64

ultrasonic signal

70

measurement module

72

pipe section

74

flow

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202017106256 U1 [0004]
• DE 202014100750 U1 [0005]
• DE 102015120381 A1 [0006]
• DE 202017000784 [0012]

Claims (10)

Apparatus (10) for applying medium to high viscosity liquid materials comprising a pumping device (12), an application head (16) fluidically connected via a hose (14) to the pumping device (12) and a control unit (50), the pumping device (12 ) comprises a follower plate (22) with a scoop pump (24), wherein the scoop piston pump (24) comprises a drive, via which a movement speed of a delivery piston (25) of the scoop pump (24) is controllable, and the application head (16) a valve (16) 36) for releasing the flow of the liquid material through the applicator head (16), characterized in that between the pumping means (12) and the applicator head (16) a flow sensor (60) for measuring the flow of the liquid material is arranged and that the Control unit (50) is arranged, the measured value of the flow during the application of the liquid material in the control of the speed of movement of För derkolbens (25) of the pump piston pump (24) to be considered. Device (10) according to Claim 1 , characterized in that the flow sensor (60) designed such that it does not touch the liquid material. Device (10) according to Claim 1 or 2 , characterized in that the flow sensor (60) is an ultrasound-based flow sensor configured. Device (10) according to one of Claims 1 to 3 , characterized in that the flow sensor (60) is received in a measuring module (70). Device (10) according to Claim 4 , characterized in that the measuring module (70) is arranged adjacent to the applicator head (16). Device (10) according to one of Claims 1 to 5 characterized in that the pump means (12) comprises a first pressure sensor (30) disposed on an outlet side of the scoop pump (24) and adapted to sense the pressure at which the scoop pump (24) injects the liquid material into the Hose (14) presses that the application head (16) comprises a second pressure sensor (32) disposed on a supply side of the valve (36) and the control unit (50) is arranged to use the speed of movement of the delivery piston (25) from readings of the first pressure sensor (30) and the second pressure sensor (32) as input values so that the pressure on the supply side of the valve (36) remains within a predetermined pressure range. Device (10) according to one of Claims 1 to 6 characterized in that the apparatus (10) further comprises positioning means (44) arranged to move the applicator head (16) relative to a component (46) Device (10) according to Claim 7 characterized in that the positioning means (44) is embodied as a robotic arm carrying the applicator head (16) and arranged to move the applicator head (16) relative to a stationary component (46). Device (10) according to one of Claims 1 to 8th , characterized in that the pumping device (12) comprises a lifting device (19) for raising and / or lowering the follower plate (22), wherein the lifting device (19) has a controllable drive. Device (10) according to one of Claims 1 to 9 , characterized in that the valve (36) is a needle valve or a rotary valve.

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