DE102004015942B3 - Mixing head for feeding reactive plastic components has rotary disk valve operated through a clutch by the motor that drives the mixing rotor - Google Patents

Abstract

Reactive components, which are controlled by a rotary disk valve (22), are supplied through connections (60) to a rotary mixer (24) with a vertical outlet. A motor (12) drives the mixing rotor through a central shaft and also moves the valve disk, when required, through a clutch and gearbox (16). The position of the valve disk is picked up by a sensor (76) and provides the control signal (64) for the clutch. The motor, clutch, gearbox, valve and mixing chamber are separate modules bolted together. The valve housing is partly conical with angled feed channels. The valve passages include connections for recycling material and for flushing.

Description

The The invention relates to a device for mixing reactive plastics according to the generic term of claim 1

Foams, potting materials, Sealants, adhesives and the like are often by the reaction produced by two or more plastic components. It must The plastic components are brought together in metered quantities and mixed together. For this the components are over controllable Valves introduced into a mixing chamber.

In the known design of the valves as needle valves, the opening and closing of the valves takes place by an axial stroke of the valve needle. This lifting movement of the valve needle leads to a certain material displacement of the component, which can lead to pressure fluctuations in the flowable material of the plastic component and thus inaccuracies in the dosage. Such inaccuracies may be particularly influential in the dosage of minute amounts. A valve system without such a material displacement during opening and closing results when the plastic channels leading into the mixing chamber ducts are opened or closed by a valve body sliding across the valve opening. The strand of the component is sheared by this valve body, without causing material displacement and compression. From the DE 33 01 911 A1 a device for mixing reactive plastics is known which has such a valve system. The cylindrical mixing chamber is enclosed by a hollow cylindrical valve body, which forms the lateral surface of the wall of the mixing chamber. The hollow cylindrical valve body has radial valve channels, which are arranged so that they can be brought by controlled rotation of the Ven tilkörpers with the ducts that supply the plastic components, for alignment to open the valve. If the valve body is rotated so that its valve channels do not coincide with the ducts, the valve is closed. The radially leading into the mixing chamber arrangement of the ducts determines the diameter dimensions of the device. The coaxial arrangement of valve body and mixer in the mixing chamber housing affect the assembly effort.

From the US 2,868,518 a device of the type mentioned is known in which a rotatable valve body terminates an axial end wall of the mixing chamber. The valve body has valve channels, which open axially into the mixing chamber and, depending on the rotational position of the valve body, connect the conduit channels to the mixing chamber or close these conduit conduits. A motor drives the mixer via a shaft which passes coaxially through the valve body. A second radially attached motor is used to rotate the valve body. As a result, the device is complex and takes up considerable space.

From the GB 863 843 a device for mixing reactive plastics is known with a mixer arranged in a mixing chamber, in which a valve body terminates an axial end wall of the mixing chamber. The valve body has valve channels, which bring by connecting the valve body conduction channels with the mixing chamber or complete. A motor drives the mixer via a shaft which passes coaxially through the valve body. The valve body is twisted manually.

Of the Invention is based on the object, a device for mixing to create reactive plastics that are simple and compact Structure and a favorable Assembly possible.

These The object is achieved by a device having the features of patent claim 1.

advantageous versions The invention are specified in the subclaims.

at the device according to the invention is the valve body formed as a valve disc, which serves as a rotatable lid Completing mixing chamber at an axial end wall. The valve disc is axial in alignment with the mixer which can be driven in rotation in the mixing chamber arranged and is coaxially penetrated by the drive of the mixer. The valve channels to lead in this way axially on the end face in the cylindrical mixing chamber. The valve device is extremely simple in this way and can be inexpensive getting produced. The feeder the plastic components and the drive of the mixer are of the same axial face in guided the mixing chamber. The extrusion of the mixed plastic takes place at the opposite axial end of the mixing chamber. The mixing chamber must therefore only by be enclosed a cylindrical wall of low wall thickness, so that small outer diameter and realize a slender construction of the device. This is particularly advantageous when the mixing device as controlled movable mixing head is used, with which the plastic precise is introduced into smaller components.

the same Motor is used to drive the mixer and the valve disc to twist. The engine is at the opposite of the mixing chamber End of the device arranged, the motor shaft with the mixer axially aligned. The mixer can be mounted directly on the motor shaft. Coaxially about the motor shaft are a switchable clutch and preferably arranged a reduction gear, via which the valve disc on the Switching the clutch controlled can be turned when the valve position changed shall be. It is not an additional one Drive for the adjustment of the valve system required. The coaxial arrangement the clutch and preferably the gearbox around the motor shaft also leads to a compact outer diameter the device.

Is appropriate the device composed of axially successively mounted modules. A first module consists of the engine. At this engine is the switchable coupling attached. To the clutch will be another Module attached to the gearbox. The gearbox closes axially the valve module to which in turn the mixing chamber with the mixer is grown. The individual modules can be put together and bolted together, allowing easy assembly results. The motor shaft is coaxially freely rotatable by the Clutch, the transmission and the valve module out. Preferably, the Mixing chamber detachable screwed into the valve module and the mixer is detachable put on the free end of the motor shaft, preferably snapped. This is a quick and easy replacement of the mixing chamber and the mixer possible. This is advantageous if the mixing chamber and the mixer of plastic residues need to be cleaned or replaced or replaced with equivalent parts of a different size should be.

in the The invention will be explained below with reference to an embodiment shown in the drawing embodiment explained in more detail. It demonstrate

1 a perspective view of the entire device,

2 a side view of the device,

3 in perspective the mixing head consisting of valve module and mixing chamber,

4 an axial section through the mixing head of 3 .

5 in perspective the gear module,

6 an axial section through the transmission module of 5 .

7 an individual representation of the cover ring,

8th a detailed representation of the valve ring and

9a -D the position of the valve in the various functions of the device.

In the 1 and 2 is shown the entire device for mixing reactive plastics. The device is total of a carrier plate 10 carried with which the device is mounted in a suitable device which guides the device and positioned to deploy the mixed plastic at predetermined locations. Such a device is, for example, a robot arm or a coordinate guide.

In the carrier plate 10 is an engine 12 , In particular, a controlled drivable electric motor attached. Axial to the engine 12 is a shiftable clutch 14 grown. To this clutch 14 closes axially a gear 16 on, which is designed as a self-contained module, which in the 5 and 6 is shown in detail. The gear 16 is by means of a flange 18 with the clutch 14 screwed. Axial to the gearbox 16 is again a mixing head 20 attached, which in turn forms a single module and in the 3 and 4 is shown in detail. The mixing head 20 consists of a valve unit 22 and a mixing chamber 24 together. To the lower end of the mixing chamber 24 a nozzle, not shown in the drawing is set, through which the plastic mixture is applied.

As can be seen from the drawing, the mixing chamber has 24 the shape of a slender hollow cylinder with a circular cross-section. In the mixing chamber 24 is a mixer 26 arranged in the form of a stirrer, which is one to the mixing chamber 24 Coaxial axis is driven in rotation. The mixer 26 has an eccentric cross-section and circumferential grooves to the in the mixing chamber 24 introduced plastic components to mix together. The construction of the mixer 26 is known in the art and can be replaced by other, also known versions of the mixer.

The drive of the mixer 26 done by a wave 28 , in which in the 3 and 4 visible upper end of the engine 12 sits and the shaft 28 drives. The wave 28 interspersed freely rotatably mounted the clutch 14 , The gear 16 and the valve unit 22 , On the lower end of the shaft 28 is the mixer 26 axially plugged and releasably axially locked by means of a snap connection. The mixer 26 is with the wave 28 torque-locking, z. B. via a polygonal cross-section, coupled.

The valve unit 22 has a housing 30 which has the shape of a cylinder and tapers conically upwards. On the top of the case 30 is an outwardly flared flange 32 screwed. The flange part 32 comes with a lower flange 34 of the transmission 16 screwed. At the bottom is the case 30 through a screwed-on floor 36 completed. The mixing chamber 24 is coaxially detachable in the ground 36 screwed.

The housing 30 has in its cylindrical portion a built-in from the bottom hollow cylindrical chamber, which at the bottom through the bottom 36 is completed. In this chamber is coaxially rotatable a valve disc 38 stored, at the bottom of a transition disc 40 is attached. The valve disc 38 and the transition disc 40 be axially through the floor and a drive sleeve 70 held. In the upper face of the valve disc 38 is an annular valve ring 42 made of a wear-resistant material, in particular of a ceramic material used. The valve ring 42 has axially through holes 44A and 44B on and in its top in the circumferential direction grooves 46A and 46B , The arrangement of the holes 44A and 44B and the grooves 46A and 46B is in 8th shown. Their function will be explained later. From the holes 44A and 44B starting run valve channels 48A respectively. 48B in the axial direction through the valve disc 38 , The valve channels 48A and 48B thereby run at an angle to the central axis of the valve disc 38 so they are aware of the larger radius of the holes 44A and 44B at the top of the valve disc 38 to a smaller radius at the bottom of the valve disc 38 to lead. The valve channels 48A and 48B lead at the bottom through the transition disc 40 into the mixing chamber 24 , For this purpose, the transition disc 40 on the one hand a continuous recess 50 on that the continuous wave 28 encloses and into which the valve channel 48A opens. Next points the transition disc 40 a through hole 52 on, which is attached to the lower end of the valve channel 48B followed. The transition disc 40 covers the flared upper axial end of the mixing chamber 24 off, with the recess 50 and the hole 52 in this axial end of the mixing chamber 24 open out. A seal 41 on the outer circumference of the transition disc 40 seals them against the mixing chamber 24 from.

In the upper conical part of the housing 30 lead ducts to the outside by means of screw terminals 60 Connecting cables can be connected. In the illustrated embodiment, ducts 54A and 54B for the supply of plastic components, ducts 56A and 56B for the recirculation of plastic components and ducts 58A and 58B intended for a detergent. The ducts lead through corresponding holes in a deck ring 62 , in its dimensions essentially the valve ring 42 corresponds and to this valve ring 42 adjacent to the end wall of the hollow chamber of the housing 30 is used. About sealing elements 39 be the valve ring 42 and the bezel 62 compressed with defined preload force. The cover ring 62 also consists of a wear-resistant material, in particular a ceramic material. The arrangement of the ducts 54A and 54B . 56A and 56B . 58A and 58B is from the view of the bezel in 7 seen. Their function will be described below.

A flowable plastic component A is the supply line from a supply via a connecting line 54A fed. From the duct 56A leads a connecting line back to the supply. Accordingly, to be mixed with the plastic component A flowable plastic component B from a supply to the duct 54B supplied and from the duct 56B recirculated to the supply. The cable channels 58A and 58B a suitable rinsing agent is supplied.

The valve disc 38 can be controlled controlled in a manner described later, wherein the valve ring 42 facing the bezel 62 twisted. Because the valve ring 42 and the bezel 62 made of a wear-resistant ceramic material, is the wear of the valve ring 42 and bezel 62 low, even if plastic components are processed with abrasive additives.

Based on 9a -D will be the operation of the valve unit 22 described.

9a shows the closed position of the valve unit. The valve disc 38 with the valve ring 42 is opposite the bezel 62 turned so that the ducts 54A and 54B for the supply of plastic components and the ducts 58A and 58B for the detergent on a closed surface of the valve ring 42 hit and closed by this. Thus, neither the components A and B nor flushing means the valve channels 48A and 48B be supplied. The ducts 56A and 56B for the recirculation lines hit the grooves 46A and 46b which extend in the circumferential direction over a certain angular range. Because these grooves 46A and 46B only in the surface of the valve ring 42 are incorporated also the cable channels 56A and 56B locked.

To the plastic components A and B of the mixing chamber 24 supply, mix and deploy, the valve disc 38 turned so that the valve ring 42 in the 9b shown dosing position occupies. In this position come the components A and B supplying ducts 54A and 54B with the holes 44A and 44B of the valve ring 42 to cover. The ducts 56A and 56B continue to fall with the grooves 46A and 46B together and the ducts 58A and 58B for the detergent will continue through the valve ring 42 locked. It is now the component A through the duct 54A and the hole 44A of the valve ring 42 in the valve channel 48A flow, then enters the recess 50 the transition disc 40 and from this into the mixing chamber 24 , Component B flows over the duct 54B , the hole 44B in the valve channel 48B and from this through the hole 52 the transition disc 40 into the mixing chamber 24 , In the mixing chamber, the plastic components A and B by means of the mixer 26 mixed and can be discharged through the nozzle, not shown. Because the recess 50 through a shaft seal 29 sealed passage of the shaft 28 encloses the plastic component A flows around the passage of the shaft 28 before the plastic component B over the hole 52 in the mixing chamber 24 is mixed. This will ensure that in the area of the shaft seal 29 the components A and B are not yet in contact with each other and react with each other. A setting of reacted plastic in the shaft seal area 29 can be prevented.

If the metered mixing and spreading of the plastic interrupted, z. B. because the device is moved to a different position for dispensing the plastic, so the valve disc 38 with the valve ring 42 in the in 9c turned recirculation position rotated. In this position open the ducts 54A and 54B through which the components A and B are supplied and the ducts 56A and 56B for the return of the components together in the groove 46A respectively. 46B , The over the duct 54A respectively. 54B inflowing plastic component A or B can through the groove 46A respectively. 46B in the duct 56A respectively. 56B flow and be recirculated via this to the respective stock. The ducts 58A and 58B for the particular detergent are still through the valve ring 42 locked.

If the device is put out of action, then the mixing head 20 preferably rinsed to the plastic components A and B from the valve and the mixing chamber 24 to remove and to prevent seizing and possible reaction of component residues. For this purpose, the valve disc 38 with the valve ring 42 in the in 9d shown rinsing position turned. In this position come the cable channels 58A and 58B for the supply of the detergent with the holes 44A respectively. 44B of the valve ring 42 to cover so that detergent in the valve channels 48A and 48B can flow through and through the transition disc 40 into the mixing chamber 24 arrives. The ducts 54A and 54B come with the grooves 46A respectively. 46B to cover and the ducts 56A and 56B are each through the valve ring 42 locked.

It is readily apparent that also a third plastic component can be supplied in a corresponding manner and recirculated by a further valve channel 48 , further cable channels 54 and 56 and a corresponding hole 44 and groove 46 in the valve ring 42 be provided. Likewise, further ducts and bores can be provided to blow compressed air through the valve channels and the mixing device and expel the detergent after rinsing.

Around the valve disc 38 to rotate between the different functional positions, according to the invention the same engine 12 used the mixer 26 drives. This is at the bottom of the engine 12 concentric with the wave 28 at the exit from the engine 12 a clutch 14 arranged. The clutch, not shown in detail in the drawing, is connected via control signals via a connection 64 be fed, engaged and disengaged. The drive side of the coupling is non-rotatable with the shaft 28 connected. The output side of the clutch drives that into the 5 and 6 illustrated gear 16 at. For this purpose engages in the assembly of the transmission 16 at the clutch 14 the output side of the coupling torque-locked in an input disk 66 of the transmission 16 , The gear 16 is a reduction gear, preferably as a so-called harmonic drive transmission (eg.

EP 0 309 197 A2 ) is trained. The input disk 66 sits firmly on the hollow core shaft 67 of the transmission. With the through the gear 16 reduced speed becomes an output disk 68 of the transmission 16 driven. When mounting gearbox 16 and mixing head 20 comes the output disk 68 in torque-locking engagement with a drive sleeve 70 the valve unit 22 , The drive sleeve 70 leads coaxially through the flange 32 and the case 30 the valve unit. With the lower end of the drive sleeve 70 is the valve disc 38 firmly connected, z. B. on the drive sleeve 70 screwed. The drive sleeve 70 is rotatable in the valve unit 22 stored. Coaxial in the drive sleeve 70 sits a bearing sleeve 72 which via radial ball bearings 74 the wave 28 rotatably supported. The wave 28 rotates freely through the hollow core shaft 67 of the transmission 16 ,

Should the function of the mixing head 20 be switched, so will the clutch 14 engaged via a corresponding control signal. The motor 12 then drives with the through the gearbox 16 reduced speed the valve disc 38 with the valve ring 42 at. The respective angular position of the valve disc 38 is through sensors 76 detected on the outer circumference of the housing 30 are arranged.

10

support plate

12

engine

14

clutch

16

transmission

18

upper flange of 16

20

mixing head

22

valve unit

24

mixing chamber

26

mixer

28

wave

29

shaft seal

30

casing

32

flange

34

lower flange of 16

36

ground

38

valve disc

39

sealing elements

40

Interface washer

41

poetry

42

valve ring

44A / B

drilling

46A / B

groove

48A / B

valve ducts

50

recess

52

drilling

54A / B

Dosing the ducts

56A / B

Recirculating ducts

58A / B

Flushing ducts

60

screw

62

cover ring

64

control connection

66

input disc

67

core shaft

68

output disc

70

drive sleeve

72

bearing sleeve

74

Radial ball bearings

76

sensors

Claims (12)

Device for mixing reactive plastics, with a mixing chamber ( 24 ), with one in the mixing chamber ( 24 ) arranged rotationally drivable mixer ( 26 ), with to the mixing chamber ( 24 ) leading line channels ( 54 . 56 . 58 ) and with a valve body, the valve channels ( 48 ) which forms a part of the mixing chamber wall and which is controlled to be movable between an open position, in which the valve channels ( 48 ) the line channels ( 54 . 56 . 58 ) in alignment with the mixing chamber ( 24 ), and a closing position, in which the valve body, the ducts ( 54 . 56 . 58 ) against the mixing chamber ( 24 ), wherein the valve body a valve disc ( 38 ) which is connected to the axis of the mixer ( 26 ) aligned axis rotatably an axial end wall of the mixing chamber ( 24 ), wherein the valve channels ( 48 ) axially into the mixing chamber ( 24 ), and a motor ( 12 ) the mixer ( 26 ) by means of a shaft ( 28 ), coaxial and rotatable through the valve disc ( 38 ), characterized in that the valve disc ( 38 ) through which the mixer ( 26 ) driving engine ( 12 ) via a coaxial with the shaft ( 28 ), controlled switchable coupling ( 14 ) and a transmission ( 16 ) speed-driven driven is rotatable. Device according to claim 1, characterized in that the transmission ( 16 ) coaxial with the shaft ( 28 ) is arranged and is freely rotatable through this. Device according to one of claims 1 or 2, characterized in that the valve disc ( 38 ) in a housing ( 30 . 32 . 36 ) is rotatably mounted and that the mixing chamber ( 24 ) detachable on the housing ( 36 ) is attached. Device according to claim 3, characterized in that the mixer ( 26 ) detachable, in particular axially latching, on the shaft ( 28 ) is attachable. Device according to one of the preceding claims, characterized in that the ducts ( 54 . 56 . 58 ) to that of the mixing chamber ( 24 ) facing away from the axial end face of the valve disc ( 38 ) to lead. Apparatus according to claim 5, characterized in that in the on the valve disc ( 38 ) adjacent inner surface of the housing ( 30 ) a cover ring ( 62 ) is used made of a wear-resistant, in particular ceramic material, through which the ducts ( 54 . 56 . 58 ), and that in the axial end face of the valve disc ( 38 ) a valve ring ( 42 ) is used made of a wear-resistant, in particular ceramic material, which on the cover ring ( 62 ) and through which the valve channels ( 48 ) to lead. Apparatus according to claim 5 or 6, characterized in that the housing ( 30 ) axially adjacent to the valve disc ( 38 ) receiving portion has a conical portion and that the ducts ( 54 . 56 . 58 ) through this conical region from the outer surface of the housing to the Ge ( 38 ) to lead. Device according to one of the preceding claims, characterized in that the with the ducts ( 54 . 56 . 58 ) to cover incoming sides of the valve channels ( 48 ) on a larger radius of the valve disc ( 38 ) are arranged as the in the mixing chamber ( 24 ) outlet ends, so that the valve channels ( 48 ) in the valve disc ( 38 ) extend at an angle inclined to the axis of rotation. Device according to one of the preceding claims, characterized in that at least two ducts ( 54 ) for supplying plastic components and at least two ducts ( 56 ) are provided for recirculating the plastic components and that the valve disc ( 38 ) or the valve ring (in 42 ) in a metering position with the valve channels ( 48 ) or with corresponding holes ( 44 ) of the valve ring ( 42 ) with the ducts ( 54 ) comes to cover for the supply of the plastic components and in a recirculation position via circumferentially extending grooves ( 46 ) the line channels ( 54 ) for the supply of the plastic components and the ducts ( 56 ) for recirculation. Device according to one of the preceding claims, characterized in that ducts ( 58 ) are provided for a detergent and that in a flushing position of the valve disc ( 38 ) the valve channels ( 48 ) or the associated holes ( 44 ) of the valve ring ( 42 ) with these line channels ( 58 ) for the detergent come to cover. Device according to one of the preceding claims, characterized in that at the mixing chamber ( 24 ) facing end face of the valve disc ( 38 ) a transitional disc ( 40 ) is arranged that the transition disc ( 40 ) a recess ( 50 ) into which one of the valve channels ( 48A ) of the valve disc ( 38 ), which is the wave ( 28 ) and with the mixing chamber ( 24 ) and that a bore ( 52 ) the transition disc ( 40 ) interspersed with the other valve channel ( 48B ) is aligned and into the mixing chamber ( 24 ) opens. Device according to one of the preceding claims, characterized in that on the one hand the engine ( 12 ) with the coupling ( 14 ), secondly the transmission ( 16 ) and to the third of the valve unit ( 22 ) and the mixing chamber ( 24 ) formed mixing head ( 20 ) each form separate building modules which are connected via flanges ( 18 . 32 . 34 ) are bolted together.