DE102012104924A1 - Filtration device for fluids - Google Patents

Abstract

A filter apparatus (100) for fluids designed as a screen-bolt changer has a housing (10) with two sieve boles (20, 30) displaceably mounted therein, wherein the housing has at least one backwash channel (41, 42) leading from the housing exterior into a housing bore (11, 12) , 43, 44), which opens in a backwash position of a screen pin (20, 30) in one of the screen cavities (21, 22, 31, 32). The backwash channel (41, 42, 43, 44) for the Siebkavität (21, 22, 31, 32) of the one located in backwash Siebbolzens (20, 30) via a Rückspülumlenkungskanal (35, 36, 25, 26) on or in the other, in production position located Siebbolzen (30, 20) out.

Description

• – wenigstens einem Eintrittsteilkanal je Siebkavität;
• – wenigstens einem Austrittskanal je Siebkavität; und
• – wenigstens einem von der Gehäuseaußenseite in die Gehäusebohrung führenden Rückspülkanal, welcher in wenigstens einer Rückspülstellung eines Siebbolzens in einer Siebkavität mündet.

The invention relates to a filtration device for fluids, with a housing having at least two housing bores in which two axially displaceable screen bolts are arranged, each having at least one Siebkavität in which a filter medium is to be arranged, and with

• - At least one inlet sub-channel per Siebkavität;
• - At least one outlet channel per Siebkavität; and
• - At least one leading from the outside of the housing in the housing bore backwash channel, which opens into at least one backwash position of a screen pin in a Siebkavität.

Such a filtering device is known from PCT / WO2004 / 026432 A1 known. This makes it possible to maintain a continuous production operation, even if one of the four screen cavities must be cleaned. By dividing the fluid flow on two screen bolts, each with two screen cavities 50% of the total filter surface can remain in production operation constantly, while the other screen areas are backwashed or completely replaced. In a preferred embodiment of the known filtration device, it is even possible to keep 75% of the total filter surface in production mode, while only one of the four screen cavities, a backwashing or replacement of the filter media.

The advantageous effect of the known filtration device, namely to be able to keep three quarters of the filter surface constantly in production operation, is based on special geometrical conditions of the inlet and outlet part channels as well as the screen pin, which allow in interaction just to flush the one Siebkavität on the same screen pin, while the other is still flowing through the production plant. Due to the narrow axial distances of the subchannels, the different flow paths, which in the 1 - 5 of the PCT / WO2004 / 026432 A1 are illustrated, only allow, it is often no longer possible to provide a so-called blocking position for the preparation of backwashing, ie an axial position of the screen bolt, in which the Siebkavität is already connected to its clean side with an outlet part channel, but still on the dirty side completely shut off from all flow paths. Without the shut-off but a pressure build-up, which is necessary for effective cleaning, not possible.

Thus, it is then necessary to make the so-called backwash channel, which establishes a connection between the dirty side of a screen cavity and the outside of the housing, lockable with a valve, so that the screen is initially exposed to the fluid, in particular the plastic melt, from the clean side can. Thereafter, the valve is opened, so that solved by the high back pressure of the fluid to the filter element stuck particles and are washed away through the backwash channel to the outside of the housing. Such a shut-off valve increases the production costs and must also be kept constantly warm during the filtration of plastic melt, so that the melt remaining in it does not freeze. Since the valve is usually attached to the outside of the housing, it must be additionally heated and / or insulated.

Object of the present invention is to improve a filtering device of the type mentioned so that the backwash channel can be shut off without an external valve.

This object is achieved by a filtering device having the features of patent claim 1.

The invention is based on no longer guiding the backwash channels directly from each screen cavity to the outside of the housing in the respective backwash channel positions of the screen bolts and attaching a valve to the muzzle, but instead of the other screen bolt which is in its production position as a valve to use.

A backwash inlet channel, which leads away from the screen cavity to be washed, leads within the housing to the housing bore for the respective other screen pin and first opens onto its lateral surface. Also, a further part of the backwash channel, namely a backwash outlet channel, which leads to an opening on the outside of the housing, opens at the lateral surface of the second screen bolt, whereby the backwash channel is interrupted altogether. As a result, a pressure can build up in the screen cavity of the first screen bolt to be flushed, which jams against the jacket surface of the second screen bolt. By a small axial stroke of the second screen pin a groove introduced at the periphery is moved to the mouths of the two sections of the backwash channel, so that they are interconnected. Thus, the flow path for the screen cavity to be washed is released on the first screen pin. The axial stroke on the second screen pin only needs a little more than the width of the circumferential groove, which according to a preferred embodiment forms the deflection point in the backwashing channel. The production operation on the second screen pin is not affected.

It is also particularly advantageous that in the separation of the backwashing channels according to the invention into two sections each, it is possible for the sieve cavities located one above the other to be on the adjacent Siebbolzen have a common backwash inlet channel, which leads depending on which of the two adjacent Siebkavitäten is being flushed to the deflection channel on one or the other screen pin. This already achieves a manufacturing advantage. The symmetrical design avoids an axial offset of individual flow paths and thus makes it possible to form the deflection channels on both screen bolts the same and to arrange them at the same axial position.

The deflection channels may be internal channels within a screen bolt, whose mouths then each end so that they form a continuous flow path with the backwash inlet channel and backwash outlet channel.

Preferably, the deflection channels are formed as simple circumferential grooves on the outside of the screen pin. Since the screen pins are guided tightly in the housing bore, there is also an outwardly closed channel.

In particular, the common backwash inlet channel can be formed by two sections which are employed in a V-shaped relationship to one another and which intersect at a point on the outside of the housing, wherein the backwash inlet channel is closed again at the point of intersection by a shut-off element. The sections can thus be easily formed by two oblique, introduced from the outside of the housing forth holes.

Although each Rückspülaustrittskanal can be performed individually to the outside of the housing. Preferably, however, the Rückspülaustrittskanal is formed from two V-shaped each other employed Rückspülteilaustrittskanälen that lead to a common end of a backwash or equal to a common outlet opening on the outside of the housing. This allows a particularly space-saving design of the flow paths, which in particular makes it possible to arrange the common outlet opening at the end face of the housing between the housing bores.

However, the particular advantage of the common backwash inlet channel described above lies in the fact that an internal flow connection can be formed between the respective dirt sides of the adjacent screen cavities, which is completely independent of the backwashing function described above. This flow connection via the common backwash inlet channel makes it possible to refill a cleaned and emptied sieve cavity from the dirty side with fluid, in particular plastic melt, and thereby vent it.

In the filtration apparatus known from the prior art, the filling always takes place from the outlet side, but where due to the pressure drop at the filtration device itself or too low a system pressure in the downstream processing machines, the fluid flow is too low to achieve a fast filling and venting and to return the affected screen cavity to the production position as soon as possible.

The double benefit of the inventive design of the backwash channel is achieved in that the Siebkavitäten each have in addition to the known vent groove, which extends in the venting position of a screen bolt from the respective top of the Siebkavität to the housing outside, a Vorflutkanal, which also from the edge of Siebkavität runs in the direction of the outside of the housing, but which extends axially less far than the vent channel and does not lead out of the housing in the venting position. As a result, the Vorflutkanal is at the venting Siebkavität no function. In contrast, in the adjacent screen cavity on the other screen pin, which is in a particular axial position, the preflow channel establishes a connection between the screen screen cavity there and the common backwash inlet channel. Furthermore, in this position, the local screen cavity is in a connection with at least one of the inlet channels in the housing.

The flow path during filling and venting thus results as follows: the fluid flows via one of the inlet part passages of the housing into a screen cavity of one screen bolt and flows from there via the preflow channel and the common backwash channel inlet channel into the adjacent screen cavity of the other screen pin. The Siebkavität fills quickly due to the pressure prevailing at the inlet side high pressure. The displaced air escapes upward through the vent groove to the outside of the housing. After complete venting both screen bolts return to the production position. Thus, any connections of the vent grooves are interrupted to the housing outside as well as the Vorflutnuten to the common backwash inlet channel. The backwash channels themselves are also interrupted, since the backwash inlet channels open again directly on the lateral surface of the screen pin.

An additional valve for closing the backwash can be additionally provided to make a backwash even if the screen bolt having the deflection channel according to the invention is repaired or maintained or for other reasons is not displaced to the position in which he To complete the backwash channel with its backwash diverting channel.

The invention will be explained in more detail with reference to the drawing. The figures show in detail:

1 a filtration device in backwash position in a side view of the inlet side;

2 a filtration device in the venting position in a side view of the inlet side;

3 the filtering device according to 1 in top view;

4 the filtering device according to 1 in a detail of a perspective view;

5 an enlargement of the view 4 ; and

6 the filtering device according to 2 in a section of a perspective view.

1 shows a filtration device according to the invention 100 with a housing 10 with two housing bores 11 . 12 in which screen bolts 20 . 30 are mounted axially displaceable. Each screen pin 20 . 30 has two Siebkavitäten in the illustrated embodiment 21 . 22 . 31 . 32 , These are from entrance subchannels 13.1 . 13.2 . 13.3 . 13.4 fed, which from a common inlet opening 13 on the housing 10 branch.

In the left image area are on the mutually facing sides of the projecting ends of the screen pin 20 . 30 circumferential grooves 25 . 35 recognizable, which are required for the backwashing process described below. The screen bolts 20 . 30 are formed symmetrically with respect to a vertical axis, so that correspondingly on the other side of the filtering device, at the respective other end of the screen pin 20 . 30 also circumferential grooves 26 . 36 are provided.

In the case 10 is for each pair of superimposed screen cavities 21 . 31 respectively. 22 . 32 a common backwash inlet channel 41 . 42 provided, which within the housing 10 runs. Each pair also has a backwash outlet channel 43 . 44 provided by a common mouth on the outside of the housing in two parts 43.1 . 43.2 (see. 4 Branched, each to one of the Siebkavitäten 21 . 31 respectively. 22 . 32 to lead.

Each of the screen cavities 21 . 22 . 31 . 32 each has at least one vent groove in the upper area 21.2 . 22.2 . 31.2 . 32.2 , Furthermore, each of the Siebkavitäten owns 21 . 22 . 31 . 32 in each case at least one Vorflutnut 21.1 . 31.1 which are both arranged close to the housing center axis, so that a connection with the mouths of the Rücklüleintrittskanäle 41 and 42 can be produced.

In 1 is the filter device according to the invention 100 with the upper screen bolt 20 in a backwash position for rinsing the upper left Siebkavität 21 ,

The lower screen bolt 30 with its sieve cavities 31 . 32 is in a production position, although not exactly centered with respect to the central entrance 13 is arranged. Nevertheless, the two screen cavities 31 . 32 of the lower screen bolt 30 by two inlet sub-channels 13.3 incident flow. The small axial displacement of the lower screen pin 30 from the middle position is necessary to the circumferential groove 35 in overlap with the mouths of the Rückspüleintrittskanals 41 and the backwash outlet channel 43 to bring and thus open the flow path for the fluid.

3 shows the filtration device 100 in backwash position in a view from above. The position of the screen bolts 20 . 30 is the same as in the side view 1 is shown, that is, the upper screen pin 20 is moved to the left.

The right sieve cavity 22 of the upper screen bolt 20 is from the entrance opening 13 flowed through. At the exit side, the fluid passes through one of the housing exit part passages 14.1 . 14.2 from behind into the left sieve cavity 21 , from there through the backwash inlet channel 41 , by the not visible here circumferential groove on the lower screen pin 30 and finally into the backwash exit channel 43 ,

4 again shows the backwash, in an enlarged section of a perspective view. It becomes clear that the backwash inlet channel 41 from two V-shaped hired parts 41.1 . 41.2 consists of a common point of intersection 41.3 have been made on the outside of the case. The intersection has subsequently been sealed again with a closure element. The backwash outlet channel 43 is similarly made: From a common point of intersection on the outside of the housing between the screen pins 20 . 30 are two oblique holes 43.1 . 43.2 in the direction of the respective screen cavities 21 . 31 brought in. The intersection remains open, however, because it forms the common backwash passage exit opening 43.3 ,

At the lower screen bolt 30 is between the end of the backwash inlet channel 41.2 and the end of the backwash exit channel 43.2 the circumferential groove 35 recognizable, through which the Rücklüleintritts- and -austrittskanäle 41.2 . 43.2 in the position shown of the lower screen bolt 30 have been associated with each other.

5 shows a further enlargement 4 , Therein, the flow path is shown by the dot-dash line.

During backwashing, the plastic melt flows from the rear, ie from the clean side, into the upper left sieve cavity 21 , and through the filter element, not shown here, into the backwash inlet channel 41 , It then enters the circumferential groove 35 on the top of the lower screen bolt 30 and about this in the lower part 43.2 the backwash outlet channel 43 to the outlet 43.3 on the housing 10 ,

The other part 43.2 the backwash outlet channel 43 opens on the lateral surface of the upper screen bolt 20 and is locked with it. Without function is in the illustrated position of the upper Siebkavität 21 also the Vorflutnut 21.1 ,

2 again shows the filtration device 100 in a side view on the entrance side. In the illustrated position of the screen pin 20 , 30 is the filling and venting of the previously cleaned, left upper Siebkavität 21 reached. Opposite the position in the 1 . 4 and 5 is the upper screen bolt 20 even further moved to the left outside, leaving the vent groove 21.2 now outside the case 10 ends. It should be noted that the Vorflutnut 21.1 , which are for the venting of their own Siebkavität 21 this is not needed, just before the housing edge ends.

At the lower screen bolt 30 is the right screen cavity 32 in production. It is still fed by one of the inlet subchannels. The left sieve cavity 31 is still just in overlap with the entrance section channel 13.3 , allowing melt into the screen cavity 31 can flow into it. The Vorflutnut 31.1 the sieve cavity 31 is in connection with the common backwash inlet channel 41 the two adjacent Siebkavitäten 21 . 31 ,

It can be clearly seen that the circumferential grooves 25 . 35 both outside the case 10 lie, so that no connection between the Rücklüleintrittskanal 41 and the backwash outlet channel 43 consists. The backwash inlet channel 41 in this position alone serves the internal transfer of the fluid from the lower Siebkavität 31 in the upper Siebkavität 21 ,

In 6 the flow path in the venting position is shown as a dot-dash line. The fluid passes from the inlet opening 13 into one of the entrance subchannels 13.3 and above in the lower Siebkavität 31 , About the Vorflutnut 31.1 will connect the screen cavity 31 and the common backwash inlet channel 41 produced. About the backwash inlet channel 41 as a bridge, the upper left Siebkavität 21 reached and filled with fluid. The displaced air escapes upwards via the vent groove 21.2 as well as further ventilation grooves to the outside of the housing 10 ,

The Vorflutnut 31.1 Also serves as a throttle to achieve a very slow filling, which allows even with highly viscous liquids a uniform, bubble-free filling. The Vorflutnut is therefore preferably wedge-shaped, so that their opening cross-section is variable by fine tuning of the axial position of the screen pin.

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

• WO 2004/026432 A1 [0002, 0003]

Claims (10)

Filtration device ( 100 ) for fluids, with a housing ( 10 ) with at least two housing bores ( 11 . 12 ), in which two axially displaceable screen bolts ( 20 . 30 ) are arranged, each having at least one Siebkavität ( 21 . 22 . 31 . 32 ), in which a filter medium is to be arranged, and with: - at least one inlet part channel ( 13.1 . 13.2 . 13.3 ) per screen cavity ( 21 . 22 . 31 . 32 ); At least one outlet channel per screen cavity ( 21 . 22 . 31 . 32 ); and - at least one of the housing outside in the housing bore ( 11 . 12 ) leading backwash channel ( 41 . 42 . 43 . 44 ), which in at least one backwash position of a screen pin ( 20 . 30 ) in a sieve cavity ( 21 . 22 . 31 . 32 ), characterized in that the backwash channel ( 41 . 42 . 43 . 44 ) for a screen cavity ( 21 . 22 . 31 . 32 ) of the one, located in backwash screed ( 20 . 30 ) via a backwash diverting channel ( 35 . 36 . 25 . 26 ) on or in the respective other, in production position Siebbolzen ( 30 . 20 ) leads. Filtration device ( 100 ) according to claim 1, characterized in that the backwashing channels ( 41 . 42 ) for the screen cavities ( 21 . 22 . 31 . 32 ) each comprise at least: - a backwash inlet channel ( 41 . 42 ), which in a backwash position of a Siebbolzens ( 20 . 30 ) with its one end in the Siebkavität to be rinsed back ( 21 . 22 . 31 . 32 ) and with its other end in the housing bore ( 11 . 12 ) for the other screen pin ( 20 . 30 ) opens; A backflush diversion channel ( 25 . 26 . 35 . 36 ) on the respective other screen bolt ( 20 . 30 ) located in at least one axial position of the other screen pin ( 20 . 30 ) to the backwash inlet channel ( 41 . 42 ) connects; A backwash outlet channel ( 43 . 44 ), of the housing bore of the other screen pin ( 20 . 30 ) to the outside of the housing ( 10 ) and in the said axial position of the other screen pin ( 20 . 30 ) on the backflushing duct ( 25 . 26 . 35 . 36 ) opens. Filtration device according to claim 2, characterized in that the superimposed sieve cavities ( 21 . 31 . 22 . 32 ) adjacent screen bolts ( 20 . 30 ) a common backwash inlet channel ( 41 ). Filtration device ( 100 ) according to at least one of claims 1 to 3, characterized in that on the outside of the screen pin ( 20 . 30 ) of each screen cavity ( 21 . 22 . 31 . 32 ) out to the outside of the housing ( 10 ) in each case at least one venting channel ( 21.2 . 22.2 . 31.2 ) and at least one preflow channel ( 21.1 . 31.1 ) whose axial extent does not extend beyond that of the venting channel ( 21.2 . 22.2 . 31.2 ), wherein the vent channel ( 21.2 . 22.2 . 31.2 ) in a venting position of a screen bolt ( 20 . 30 ) from a screen cavity ( 21 . 22 . 31 . 32 ) to over the outside of the housing ( 10 ) and at the same time at the other screen pin ( 20 . 30 ) the screen cavity ( 21 . 22 . 31 . 32 ) with an inlet sub-channel ( 13.1 . 13.3 ) and with the Vorflutkanal ( 21.1 . 31.1 ) and the sewer ( 21.1 . 31.1 ) to the backwash inlet channel ( 41 . 42 ), which at the to be deaerated Siebkavität ( 21 . 22 . 31 . 32 ) opens. Filtration device ( 100 ' ) according to at least one of claims 2 to 4, characterized in that the Rückpülaustrittskanal ( 43 ' . 44 ' ) with a valve ( 50 ' ) is closable or the backwash inlet channel ( 41 . 42 ) is to be interrupted by a valve. Filtration device according to at least one of claims 2 to 5, characterized in that the backwashing inlet channel ( 41 . 42 ) made of two V-shaped back flushing member inlet channels ( 41.1 . 41.2 ) formed at one point ( 41.3 ) on the outside of the housing ( 10 ), wherein the backwash inlet channel ( 41 . 42 ) is closed at the intersection by a shut-off or interrupted by a valve. Filtration device according to at least one of the preceding claims, characterized in that the backwash outlet channel ( 43 . 44 ) made of two V-shaped backflushing part outlet channels ( 43.1 . 43.2 ) formed to a common outlet opening on the outside of the housing ( 10 ) to lead. Filtration device according to claim 7, characterized in that the outlet opening at the end face of the housing ( 10 ) between the housing bores ( 11 . 12 ) is arranged. Filtration device according to at least one of the preceding claims 1 to 8, characterized in that the backwash diverting duct ( 25 . 26 . 35 . 36 ) as one on the outer surface of the screen bolts ( 20 . 30 ) formed circumferential groove is formed. Filtration device according to at least one of the preceding claims 1 to 8, characterized in that at least one backwash diverter channel is formed within the screen pins and has two orifices on the outside. Filtration device according to at least one of the preceding claims, characterized in that - each screen pin has at least two screen cavities ( 21 . 22 . 31 . 32 ), in each of which a filter medium is to be arranged, - that the entrance channel ( 13 ) in each case at least one inlet sub-channel ( 13.1 ... 13.4 ) per screen cavity ( 21 . 22 . 31 . 32 ) is branched; - That the outlet channel in each case at least one outlet sub-channel ( 14.1 . 14.2 ) per screen cavity ( 21 . 22 . 31 . 32 ) is branched.

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