DE8424818U1 - DIRT FILTER FOR THERMOPLASTIC MEDIA - Google Patents

Description

, • 1/5 S -:, ::,.! :: 'p:' 4OO96 7/31/84. Dust filter for thermoplastic media

The invention relates to a dirt filter for viscous, flowable, thermoplastic media with a housing that can be opened recessed filter space in which a loose locking body sits positively in the filter position;

with a lead cut out in the housing, which is connected to a circular Cross section opens into the filter space coaxially to a flow axis;

with a derivation recessed in the housing, which has a circular cross-section coaxial to the flow axis on that of the mouth of the Supply line on the opposite side emanates from the filter chamber; whereby the filter space and the blocking body are rotationally symmetrical to the river oss and are designed smooth and vobei the inner diameter of the filter space, measured perpendicular to the flow axis, is larger everywhere than the corresponding on the same axial Height measured outer diameter of the blocking body in the filter position and the difference between these two diameters in the direction of flow initially decreases except for a blocking cross-section an annular barrier gap and increases again behind this.

In injection molding with thermoplastic material that chewy flowing through heating medium is supplied to spray nozzle vend driven one of these in an attached injection mold. Contaminants in the medium, for example from metal splinters, are retained at the blocking gap in the dirt filter. If a lot of dirt has collected in front of the barrier gap, the dirt hinders the further flow of the medium and must be removed.

In a dirt filter known from DE-GM 84 02 924 the For this purpose, the filter housing is opened, the locking body removed and the filter chamber cleaned.

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The object of the invention is to eliminate the need for opening the housing to avoid cleaning purposes.

The solution to this problem is characterized in claim 1. 5

Then it is sufficient to clean the locking body in its cleaning position to move so that the accumulated dirt is carried away by the flowing medium. From the spray nozzle a portion of heavily soiled medium then occurs. This portion is discarded. Then the locking body is back in its filter position has been moved and spraying operation can continue will.

During normal filter operation, the flowing through exercises Medium pressure in the direction of flow on the blocking body. It is therefore advisable to move the blocking body against the direction of flow in to design its cleaning position adjustable.

For a perfect function it is particularly important that the barrier gap is exactly dimensioned. For this purpose, the locking body in the filter position exactly in a predetermined position. This is achieved by an embodiment of the invention according to claim 3. The locking body is then by the pressure of the flowing medium in its through the stop surface and the stop counter surface is driven in a defined filter position and takes place on these surfaces that are correspondingly stable can be, also enough hold against the possibly very high pressure of the flowing medium.

The guidance of the locking body can be designed very simply, on one side or on both sides, as is the subject of the claims 4 to 6 is.

The device for adjusting the locking body in the cleaning position and back to the filter position should be designed and handled as simply as possible. A corresponding design is the subject of claim 7. By screwing in the grub screw, it presses on the conical surface and pushes the blocking body against the flow direction in the cleaning position. If the grub screw is turned back again, the

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The barrier body, following the pressure of the pending medium, moves back into its barrier division.

It is desirable for a dirt filter to be the unavoidable η to keep the flow resistance in the area of the blocking body as small as possible and adjust the filter effect through To enable replacement of the locking body against a differently sized one. This is made possible in a particularly simple way by an embodiment according to claims 9-10

If there is a lot of dirt, it is advisable to first separate out the large dirt particles, then smaller ones, and so on, in order to keep the accumulation of dirt at one point small in the interest of long-term operation. You can do this hold several appropriately dimensioned dirt filters one behind the other. This effort is avoided by an embodiment of the invention according to claim 10, in which a multiple staggered Filtering in a single blocking body is possible and easy cleaning is also offered. 20th

The invention will now be explained in more detail with reference to the accompanying drawing.

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In the drawing shows:

Figure 1 is a dirt filter according to the invention with the blocking body in the filter position, cut in half, half in view, FIG. 2 the section II from FIG. 1, FIG. 3 the section III from FIG. 1, FIG. 4 shows the section IV from FIG. 1, FIG. 5 shows the locking body from FIG. 1 alone

View according to arrow V, Figure 6 the dirt filter from Figure -1 but with the

Locking body in cleaning position,

Figure 7 shows in partial section another embodiment of a dirt filter, which with three Barring gaps is equipped »and FIG. 8 shows a further exemplary embodiment in partial section a dirt filter.

In the drawing, 1 denotes the filter housing, the consists of two parts 2 and 3. The two parts 2 and 3 are releasably connected to one another along the screw connection 4. To the To facilitate the screw connection are on part 2 hexagon wrench flats 5 'and on part 3 hexagonal wrench flats 6 are provided. The front end of the part 2 is designed as a spray nozzle 7. At the rear end of part 3 is a connection

² ^ socket 8 with external thread 9 and an associated stop surface 10 for screwing the housing to an upstream supplier for the pressurized, flowable, thermoplastic medium, for example plastic,

In the housing 1 there is a supply line 11 and a discharge line 12, respectively with a circular cross-section coaxially to the flow axis 14. The feed line 11 opens into a filter space 13, from which the discharge line 12 starts on the opposite side. The flow direction for the thermoplastic medium corresponds the arrow V.

A loose locking body 15 is inserted in the filter space 13 in Figure 1 in the filter position, which it assumes during filter operation, is drawn. in this filter position lies the

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Blocking body 15 rait a coaxial to the flow axis 14, annular, in the direction of flow stop surface 16 on one Stop mating surface 17 of the housing 1, which is also ring-shaped and is formed coaxially to the flow axis 14 and is opposite to the flow direction.

The locking body 15, apart from slots 18 to 21, is designed to be rotationally symmetrical to the Flußachs.-3 14 and is coaxial to the river axis and to the also rotationally symmetrical from formed Filter space 13 arranged. The middle area of the locking body 15 has the basic shape of two with their base 22 standing cones 23, 24. The locking body has on its circumference along the abutting base surfaces a Rounding off 25. The two ends of the locking body are designed as guide bodies 26, 27. The two guide bodies fit positively into guide recesses 28, 29 of the housing and are in these guide recesses along the flow axis 14 different led. The blocking body can move from the filter position shown in Figure 1 against the direction of flow can be moved into the cleaning position shown in FIG. In filter position, in. Beiaigungsstelluhg and in all The blocking body maintains its position coaxial with the flow axis 14 in intermediate positions.

Both guide bodies 26, 27 are distributed over their circumference the already mentioned slots 18 to 21, which extend along extend the flow axis and allow the flow of the medium.

The outer diameter of the locking body according to double arrow 30 is except in the area of the slots 18 to 21, everywhere smaller a2s the inside diameter measured at the same axial height according to the double arrow 31 of the filter space 13 * The result is that an annular gap 33 is cut out everywhere in the filter space remains through which the filter medium can flow. The filter medium thus enters the supply line, from there through the Slots 18, 19 in the space 33 and from there through the Schlitaie 20, 21 in the discharge and from there through the nozzle 7

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In the area of the rounding 25, the space 33 is narrowest, so that there is an annular locking gap 34, which for the flow of the medium forms the point with the narrowest passage width. The result is that dirt particles in front of this barrier gap 34 be withheld. The difference in diameter between the inside diameter of the filter chamber and the outside diameter of the locking body initially decreases in the direction of flow in the area 35 in front of the locking gap 34 and in the area 36 M-nter the locking gap again to. The decrease in diameter differences ^ in the area 35 is much stronger than the increase in the area in this way occurs in the direction of flow in front of the barrier gap a dirt pocket 38 in which dirt can collect. This dirt pocket is made as large as possible, it extends almost to the guide body 27.

The inside diameter of the filter space is larger in the direction of flow in front of the blocking gap 34 than at the level of the blocking gap. when the locking body gets into its cleaning position shown in FIG widest area of the locking body, this further point of the Opposite the filter space and instead of the narrow blocking gap, a wide cleaning gap 40 is created.

The passage width of the cleaning gap is expediently somewhat larger than the passage width of the slots 18 and 19.

With a receiving body 45 is referred to, which is screwed with the thread 44 into the housing. In this receiving body a grub screw serving as an adjusting screw is inserted coaxially 41. The grub screw is screwed to the receiving body 45 through the thread 48 and its free end is inserted into the Hole 49 of the housing 1. The grub screw 41 has an Allen key receptacle 42 on. In the receiving body a screw plug 46 is screwed by means of the thread 47, the one has a central breakthrough through which the Allen key

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would take 42 is accessible from the outside. The grub screw 41 is directed radially onto a conical surface 42 of the locking body. This conical surface 43 is annular and coaxial with the flow axis 14 and narrows in the direction of flow. The grub screw 41 is in the filter position of the filter body shown in FIG directed at the wide end of the conical surface. In this position the grub screw is turned back and its head is tight against the screw plug 46, so that there is a Seal arises. If the grub screw 41 is tightened, then it pushes the locking body into its cleaning position and slides on the conical surface 43 towards the narrower end of the conical surface. The blocking body has reached its cleaning position, when the head of the grub screw hits the lower shoulder 59 of the receiving body 45. In this cleaning position of the grub screw, there is a seal between the shoulder 59 and the head of the grub screw 41. The seals of the head of the grub screw in the filter position and in the cleaning position of the grub screw can be favored by an annular cutting edge on both sides of the head of the grub screw, which is in the locking screw respectively presses into the shoulder 59. If the grub screw is turned back from its cleaning position into the position shown in FIG filter position shown, then the blocking body, following the pressure of the medium, gives way to its in figure 1 drawn filter position back.

In operation, the slots 18, 19 act as a pre-filter and the Locking gap 34 as the main filter, in front of the locking gap 34, dirt collects in the dirt pocket 38 and is held back and finally the pocket fills, if that's done then the flow restriction by this dirt collected in the pocket is so great that the operation is interrupted got to. The grub screw 41 is now tightened so that the Lock gap 34 opens to the cleaning gap 40 and that Medium can take the dirt collected in the dirt bag with it. The slots 20, 21 and the nozzle 7 are wide enough so that the dirt can pass through there unhindered. The portion of the medium enriched with the dirt is discarded. At-

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then the grub screw 41 is turned back again and the blocking body moves back into its filter position and the Spraying operation can be continued.

In front of the slots 18, 19 only relatively large ones collect Particles of dirt »which, if at all, are very rarely expected so that no disturbances due to accumulated dirt are to be expected there even after a long period of operation. But if once such a fault occurs, operation must be interrupted are and the filter housing can be cleaned in the open state, it is essential that according to the invention of normally accumulating dirt is collected in the dirt pocket and by briefly actuating the grub screw can be blown out.

The embodiment shown in Figure 7 differs from that shown in Figure 1 to 6 only by the Design of the filter space and the locking body, so that three locking gaps 50 to 52 located one behind the other are created.

The barrier gap 50 has a larger passage width than the barrier gap 51 and this in turn has a larger passage width as the blocking gap 52. Cleaning gaps 53, 54, 55 and dirt pockets 56, 57, 58 are assigned to the three blocking gaps. The locking gaps widen to the respectively assigned cleaning gap when the locking body is only dash-dotted in its indicated cleaning position is adjusted. The cleaning gaps 53, 54, 55 all have a larger passage width than the blocking gap 52, so that the dirt from all three dirt pockets through all cleaning gaps unhindered can flow off when the blocking body is in its cleaning position.

The exemplary embodiment shown in FIG. 8 differs from the exemplary embodiment shown in FIGS. 1 to 6 only through the design of the filter space 33 '. figure

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8 shows the dirt filter in the filter position. In this filter position, the locking body 15 ¹ is pushed back against the flow direction by the screwed-in grub screw G 41 '. In this position there is only a narrow blocking gap 34 'in the space 33', through which dirt particles that collect in the dirt pocket 38 are retained. For cleaning purposes. the grub screw 41 'is turned back. The sporr body 15 * is then driven forward through the filter medium in the direction of flow, into its cleaning position, in which it strikes with its stop surface 16 'on the stop counter surface 17 *. In this cleaning position, not shown in FIG. 8, the blocking gap 34 ¹ has widened to a wider cleaning gap 40 '. Otherwise, the embodiment of Figure 8 is designed in the same way as the embodiment

"5 5 example according to Figure 1 to 6. Corresponding parts in Figure 8 with the same reference number as in Figures 1 to 6, In contrast to this, however, denotes with a trailing dash.

In a modification of the illustrated embodiments, the slots 18 to 21 corresponding slots can also be in those Housing parts can be provided which the guide recesses 28, 29 surrounding corresponding guide recesses. Instead of the contactors, channels can also be provided. Under Under certain circumstances, a single guide body at one end is sufficient of the locking body.

Instead of one or three barrier gaps as provided in FIG. 1 or FIG. 7, a different number can also be used Provide barrier gaps with associated cleaning gaps and dirt pockets, where you can determine the diameter ratios selects accordingly as indicated in the text relating to FIG.

Claims (10)

··: · ρ 40 096 7/31/84. • ■ · Claims 1 1. Dirt filter for viscous, flowable, thermoplastic media with a filter space recessed in an openable housing, in which a loose locking body sits positively in the filter position; with a feed line recessed in the housing, which has a circular cross-section and is coaxial with a plus axis in the filter chamber flows out; with a derivation recessed in the housing, which is marked with a circular Cross-section extending from the filter chamber coaxially to the flow axis on the side opposite the mouth of the feed line; wherein the filter space and the blocking body are designed to be rotationally symmetrical to the flow axis and smooth, and the inner diameter of the filter space, measured perpendicular to the flow axis, is everywhere greater than the corresponding outside diameter measured at the same axial height of the one in the filter position Blocking body and the difference between these two diameters in the flow direction initially decreases except for a blocking cross-section of an annular barrier gap and behind this increases again, characterized in that the locking body (15) with a closed housing (1) from its filter position along the flow axis (14 x) is displaceable to a cleaning position, and that when the blocking body is in the cleaning position, an annular cleaning gap (40) is formed instead of the blocking gap (34), and that the passage width of the cleaning gap is larger than that of the blocking gap. 2. Dirt filter according to claim 1, characterized in that the blocking body (15) counter to the flow direction in its Rest position is adjustable. 3. Dirt filter according to claim 2, characterized in that the blocking body (15) is directed in the flow direction, for The flow axis (14) has a coaxial, annular stop surface (16), that on the housing (1) an adjacent to the filter space (33), directed against the direction of flow, for Flow axis coaxial, annular stop counter surface (17) is provided, and that in the filter position of the locking body, the locking body with its stop surface (16) on the stop counter surface (17) of the housing (1) is supported in an adjacent manner f. 4. Dirt filter according to one of the preceding claims, characterized in that at least at one end of the blocking body (15) as an extension of the same a guide body (26,27) is attached, the form-fitting and displaceable in the flow direction in a guide recess' (28.29) of the housing (1) fits, and
that in the guide body and / or in the parts of the housing surrounding the guide recess, channels (18-21) distributed over the circumference are cut out for the thermoplastic medium, the passage width of which is greater than that of the barrier gap (34). ² ^ 5. Dirt filter according to claim 4, characterized in that the channels (18-21) are formed by slots in the guide body (26,27) which extend along the flow axis (14). 6th Dirt filter according to Claim 4 or 5, characterized in that one at each end of the blocking body (15) Guide body (26,27) is attached with an associated guide recess (28, 29) in the housing (1). 7 · Dirt filter according to one of the preceding claims, characterized in that a narrowing in the flow direction, annular conical surface (43) coaxial with the flow axis (14) is provided on the outside of a guide body (26, 27), J ...! 3- '*.' * .. '' ·· 'ρί 40 096 31. 7.84 * and that one designed as an adjusting screw, accessible from the outside Grub screw (41) in the housing (1) is arranged radially to the river axis (14), which is in the filter position located locking body (15) on the wide end of the conical surface (43) is directed. 8. Dirt filter according to one of the preceding claims, characterized in that, based on the. in filter position located locking body (15). upstream of the barrier gap (34) a dirt pocket (38) is formed by the difference in diameter between the upstream of the barrier gap the outer diameter of the blocking body and the inner diameter of the filter space (33) are stronger in the direction of flow decreases as this diameter difference increases on the downstream side of the barrier gap in the direction of flow. 9. Dirt filter according to one of the preceding claims 1 to 8, characterized. that the locking body (15) in its central area has the basic shape of two cones with their bases placed one on top of the other, that the locking body on its periphery (25) along the abutting Base surfaces is rounded, and that, based on the filter position of the blocking body, the Locking gap (34) at the level of the abutting base surfaces lies. 10. Dirt filter according to one of the preceding claims, characterized characterized in that, in relation to the direction of flow, several blocking gaps (50-52) are provided at a distance one behind the other are, that, based on the direction of flow, the difference in diameter between the outer diameter of the locking body and the inner diameter of the filter space decreases in front of each locking gap and behind it increases again, that each locking gap is assigned a cleaning gap (53-55) for the locking body in the cleaning position. ...._.... ₄ .. _ .. ·· ρ 40 09ί 7/31/84 » that of these barrier gaps in the flow direction the first has the largest passage width, the next one has a smaller passage width and so on, and that the cleaning gaps all have larger passage widths than the largest barrier gap.