WO1995032785A1

WO1995032785A1 - Self-cleaning filter cartridge for use with liquid or gaseous mediums

Info

Publication number: WO1995032785A1
Application number: PCT/LU1995/000001
Authority: WO
Inventors: Roger Greiveldinger
Original assignee: Roger Greiveldinger
Priority date: 1994-05-31
Filing date: 1995-05-10
Publication date: 1995-12-07
Also published as: AU2420995A

Abstract

The proposed filter cartridge consists of an approximately cylindrical housing (10) and an inner filter insert (22) provided with a fine-mesh filter screen (32) which forms the covering surface of a cylindrical or truncated cone-shaped filter basket (30). In addition, a closure unit (66) is provided to force the liquid or gas flow through the filter screen (32) or alternatively to allow it at least in part to flow along the filter screen (32) and out of the cartridge, the dirt particles which adhere to the filter screen (32) being detached by the current and pressure and flushed away.

Description

SELF-CLEANING FILTER CARTRIDGE FOR LIQUID OR

GASEOUS MEDIA.

The present invention relates to a self-cleaning filter cartridge for liquid or gaseous media with an approximately cylindrical housing and an inner filter insert.

The invention relates in particular to filter inserts combined with aerators for water outlet fittings and filter inserts for shower heads or for the water supply of electrical household appliances, such as washing machines, dishwashers, coffee machines, etc.

To produce a gentle water jet, an aerator is usually screwed onto the water outlet fitting and is available as a standard kit with a filter. The filter is a disc-shaped sieve that is arranged across the water flow upstream from the bubbler. In the aerator, the water jet is distributed through a distributor disc with fine bores arranged transversely to the water flow.

However, it is well known that both these filter screens and the aerators block relatively quickly with dirt particles and lime particles and adversely affect the function of the aerators. The sieves and aerators become blocked particularly quickly with hard water with a high lime content, in particular because the lime particles form in the pipes and water heaters and are flushed into the fittings.

There are filter sieves made of lime-repellent plastic, but the disadvantages are not eliminated because dirt and lime particles settle on the sieve and collect and clog the sieve. Dirt particles pressed by the water pressure through the sieve accumulate on the perforated aerator discs and clog them. It is therefore necessary to regularly disassemble the filter cartridges and aerators and to clean them 5 or descale them, or to replace them. However, it also happens, particularly in the case of advanced contamination and calcification, that the bubbler or filter inserts are stuck in such a way that there is a risk that the fitting will be damaged

10 or that maintenance must be entrusted to a specialist.

The object of the present invention is therefore to create a filter cartridge with a self-cleaning filter insert, in which the

15 Cleaning is either triggered manually at the desired time or triggered automatically when the degree of contamination is increased.

To achieve this object, the present invention proposes a filter cartridge, which thereby

20 is characterized in that the filter insert has a fine-meshed filter screen, which forms the outer surface of a cylindrical or truncated cone-shaped basket and is carried by this in the cartridge housing and supported in the current direction, and that means

2.5 are provided in order to either force the flow of the liquid or gaseous medium through the filter screen or at least partially let it flow out of the filter cartridge along the filter screen, with the dirt particles adhering to the filter screen from the flow

30 and torn free of pressure and washed away.

An important feature is that the screen surface is no longer arranged transversely to the flow direction as in known filter inserts, but simply parallel or at an acute angle to the flow

35 direction. While in the known filter seven the dirt particles under pressure on the transverse arranged sieve surface and pressed into its mesh, so in the present invention most dirt particles slide on the inclined or vertical sieve surface onto the bottom of the filter basket or the filter insert. Those particles which nevertheless adhere to the sieve surface are detached from it during the cleaning process by the high pressure which acts tangentially on the sieve surface. According to a further feature of the invention, the mesh of the filter screen is extremely fine, on the order of approximately 100 μm. This not only achieves a good filter effect, but above all it ensures that the filter basket is not emptied due to the surface tension when the tap is closed. As a result, no or at most very little limescale deposits can result from water evaporation. If the filter screen is also made of lime-repellent material, the problems of limescale deposits are definitely eliminated. The fine mesh of the filter sieve also ensures that the perforated distributor disks and distributor sieves of the aerators do not become blocked.

When used with water outlet fittings, the housing of the filter cartridge has a thread so that it can usually be screwed onto the mouthpiece or outlet opening. This means that the fitting does not require any changes to adapt the self-cleaning filter cartridge according to the invention. When used in fittings, an aerator known per se is arranged downstream of the filter basket in the housing.

According to the invention, various configurations are provided for triggering the cleaning process manually or automatically. In a first category of designs, the filter screen is flowed through from the inside to the outside. Here, the impermeable bottom of the filter basket is extended downstream by an axial emptying tube, a closing element being present in the filter basket, which closes the outlet into the emptying tube during normal flow operation and frees the outlet into the emptying tube during cleaning operation.

According to a first embodiment, the spherical or hemispherical closing member is carried by an elastic spring clip which is fastened in the filter basket on the one hand and on the other hand is connected to a radial driving pin which penetrates the filter screen and is guided in an arcuate slot in the housing. Outside of the housing, the driver pin is anchored in a rotating ring sealingly attached to the housing. By manual actuation of the rotating ring, the driver pin is displaced through the arcuate slot, the closing member being moved laterally and opening the outlet into the emptying pipe. This triggers the cleaning process.

Due to the movement of the driver pin, the filter screen is also rotated axially relative to the filter basket. In this case, dirt particles adhering to the outside of the filter screen are wiped off the lateral struts of the filter basket.

When used in household appliances with an automatic water supply, the drain pipe preferably opens into a lateral drain pipe to which a waste water hose is connected.

According to a further embodiment of the invention, the filter cartridge has a stationary, fixed closing member fastened to an inlet plate, while the filter basket with the emptying tube is carried by a compression spring and resiliently in counter Current direction is pressed against the closing element. As the filter sieve becomes soiled, the flow through the sieve decreases, which means that the pressure rises upstream and falls downstream. When the pressure difference that arises in this way overcomes the force of the spring, the filter basket is displaced downstream of the closing element, the outlet being cleared through the emptying pipe. This creates a violent flow through the emptying pipe which sweeps the dirt particles in the filter basket and on the surface of the sieve.

In a further embodiment of the invention, the filter basket is axially stationary, while the closing element, which is designed as a piston, is axially movable in a cylindrical guide sleeve and forms a piston chamber with the latter, in which a compression spring is arranged, which seals the piston with its conical seal ¬ surface presses on the edge of the drain pipe, the piston having an axial pressure compensation channel through its sealing surface and means are provided to adapt the pressure in the piston chamber to the pressure on the side downstream of the screen.

As a result, the piston is exposed to a differential pressure, namely in the direction of the closed position (that is, normal flow operation) under the pressure downstream of the sieve and in the direction of the opening position (that is, cleaning operation) under the pressure upstream of the filter sieve. When the surfaces exposed to these differential forces are calculated appropriately, the piston opens automatically at a differential pressure corresponding to a certain degree of contamination, which triggers the high-pressure cleaning flow through the drain pipe.

The invention also provides two advantageous variants of this embodiment, in order to adjust the pressure in the piston chamber to the pressure downstream of the sieve adapt. According to a first variant, the piston wall and the sleeve wall each have a radial opening, which are flush with one another in the closed piston position and which are closed with a sieve which has the same meshes as the filter sieve and a corresponding pressure drop.

According to a second variant, a channel is provided which opens into the sleeve above the piston in its closed position and connects the piston chamber to the chamber downstream from the filter screen.

In both variants, these connections are interrupted when the piston opens, so that the pressure in the piston chamber drops via the axial pressure compensation channel and the piston is displaced to its upper end position under the full flow pressure. Since the piston does not automatically move into its closed position due to the high pressure, the cleaning operation lasts until the water tap is turned off. The invention also provides two advantageous variants for manually triggering the cleaning operation in this embodiment. According to a first variant, it is sufficient to close the lower outlet end of the drain pipe with the fingertip. The pressure that builds up in the drain pipe and the pressure already in the filter basket are sufficient to lift the piston from its seat and thus initiate the cleaning process.

According to a second variant, a pressure pin is provided in the emptying tube, which can be pushed up manually in order to lift the piston from its seat.

In a second category of designs, the filter screen is flowed through from the outside to the inside. Here, the bottom of the filter basket is at least partially open, while the housing wall can be closed Has openings to allow a lateral outlet from the filter cartridge during cleaning.

According to a preferred embodiment, the housing wall has a plurality of radial openings which can be opened or closed by means of a rotatable closing element arranged on the outside of the housing.

In an advantageous embodiment, the closing member consists of a sealing ring which is held and guided on a ring-shaped shoulder on the outside of the housing by means of a rotating sleeve and a clamping ring and which has radial and axial outlet openings corresponding to the radial openings of the housing wall. The sealing ring furthermore preferably has a radial adjusting screw guided in an arcuate groove of the housing, so that when the sealing ring is rotated, the ends of the groove on both sides determine the open or closed position of the sealing ring. Exemplary embodiments of the invention are shown in the drawings, in which the same parts are designated with the same reference numbers, and are described in more detail below. Show it :

Figure 1, an axial longitudinal section through a first embodiment of a filter cartridge according to the invention;

Figure 2 is a side view of the filter insert; Figure 3, a variant of the embodiment of Figure 1; FIG. 4 shows an axial longitudinal section through a second exemplary embodiment of a filter cartridge according to the invention;

Figure 5, an axial longitudinal section through a first variant of a third embodiment of a filter cartridge according to the invention; Figure 6 is an axial longitudinal section of a second variant of the third embodiment in the position corresponding to normal flow operation and

FIG. 7, the variant according to FIG. 6 in the cleaning position;

FIG. 8 shows a top view of a fourth exemplary embodiment;

Figure 9, a longitudinal section along the section plane A-A in Figure 8; Figure 10 is a view in the direction B-B in Figure 9;

FIGS. 8a, 9a and 10a, views corresponding to FIGS. 8, 9 and 10, of a variant of the fourth exemplary embodiment.

FIG. 1 shows an example of a filter cartridge intended for water fittings. This consists of a cylindrical housing 10 made of metal or plastic with an upper outer or inner thread 12 in order to be screwed onto the mouthpiece of a faucet or mixer tap, not shown, in the usual way. The housing 10 also has flats 14 on the opposite side to loosen the cartridge with a suitable tool if this is not possible manually.

In the lower part of the housing 10 is a known aerator 16, which can be inserted from above into the housing 10 against an annular inner shoulder 18. A spacer bush 20 is inserted above the bubbler 16 and supports a filter insert 22 according to the invention. On the filter insert there is an inlet disk 24 with inlet openings 26 and an annular seat 28 for a seal, not shown.

The filter insert 22 consists of a carrier basket 30 made of corrosion-resistant metal or lime-repellent material with a truncated cone-shaped lateral surface slightly converging in the direction of flow. On the inside A fine-meshed, appropriately shaped filter screen 32 with a mesh width of approximately 100 μm is also located on the lateral surface, likewise made of corrosion-resistant metal or lime-repellent material. As shown in FIG. 2, the outer surface of the support basket 30 consists of struts 34 which delimit the lateral sieve surfaces. The basket bottom consists of a closed, annular disc 36 whose central opening forms the seat of a closing element 40. An axial emptying pipe 38 extends from the opening in the basket base 36 through the aerator 16 to the underside of the filter cartridge.

The closing element 40, which is formed in the form of a spherical segment in the example shown, is carried by a resilient spring clip 42 which is fastened on the one hand in the basket base 36 or on the emptying pipe 38 and on the other hand is connected to a driving pin 44 which extends radially through the filter screen 32 and into an arcuate slot 46 is carried in the housing. Outside of the housing 10, the driving pin 44 is anchored in a rotating ring 48. This rotary ring 48 is rotatably arranged on the circumference of the housing by means of seals.

In the closed position according to FIG. 1, the flow takes place exclusively through the filter screen 32, with entrained particles remaining on the inside of the fine-meshed screen 32 or slipping onto the bottom of the filter basket 30. If the flow rate decreases due to the contamination of the filter screen 32, the cleaning process can be triggered manually. For this purpose, the rotating ring 48 is rotated relative to the housing 10, the driving pin 44 being pivoted from the left-hand position shown in FIG. 2 in the direction of the arrow to the right into the dashed position. The two positions are preferably by corresponding recesses on two neighboring ones Struts 34 of the filter basket 30 determined. When the flexible spring clip 42 bends, the closing member 40 is lifted from its seat and moved laterally, so that the outlet is cleared through the drainage pipe 38 and the water can flow out through the drainage pipe 38 at maximum pressure. Due to the high pressure of the water jet acting at an acute angle on the sieve surface, the deposits on the sieve surface are torn off and washed away with the particles deposited on the bottom basket through the emptying pipe 38, so that the filter insert 22 is cleaned in a very short time and the cleaning process by rotating the driving pin 44 can be ended in the opposite direction. It is possible to load the driving pin 44, for example between the filter insert 22 and the spacer bush 20, by a spring (not shown), so that the cleaning process is initiated against the spring force and, when the rotating ring is released, it is automatically released under the action of the spring is pivoted back into the normal flow position corresponding to FIG. 1.

The embodiment according to FIG. 1 is less suitable for applications in household appliances because the dirt particles would be swept into the consumer circuit by the drain pipe 38. 3 therefore provides a variant of the embodiment according to FIG. 1 for use in household appliances.

The filter insert 22, as well as the actuation and mode of operation in the variant according to FIG. 3 remain unchanged. However, the housing 50 has been modified such that the aerator 16 from FIG. 1 is omitted because it is not required for the intended application. The shortened drain pipe 52 opens into a lateral drain port 54, which is connected to a sewage hose can, so that the dirt particles do not get into the consumer circuit during the cleaning process, where they could be deposited again or cause damage. Only the filtered water reaches the consumer circuit through outlet 56.

Depending on the application, the rotation of the rotating ring 48 can also take place via an electrical, magnetic, hydraulic or pneumatic remote control. In the embodiment according to FIG. 3, the closing element 40 with the rotating ring 48 can simply be replaced by a shut-off element in the connecting piece 54 or in the emptying hose.

FIG. 4 shows an embodiment of a self-cleaning filter cartridge according to the invention with an automatic cleaning operation. In this embodiment, the basket 30 of the filter insert 22 is not carried by the bushing 20, but is axially movable therein and is supported by a compression spring 58 which is seated on the inside of the bushing 20 on the bubbler 16. The drain pipe 38 is also movably guided by the aerator 16. On the underside of the inlet disk 24 there is a stationary, axial pin 60, the conical or spherical lower tip of which forms the closing element. The filter insert 22 is accordingly elastically loaded in the counterflow direction by the compression spring 58, the emptying tube 38 normally abutting against the closing element 60 and the flow occurring exclusively through the filter screen 32. When the flow rate decreases due to contamination of the filter screen 32, the pressure upstream of the screen 32 increases. When the force generated by this pressure increase and directed vertically onto the basket base 36 overcomes the opposite force of the compression spring 58, the filter insert 22 with the drain pipe 38 is displaced axially downward, whereby the basket bottom 36 lifts off the closing member 60 and releases the outlet into the drain pipe 38. In the cleaning process triggered in this way, the dirt particles accumulated in the filter insert 22 are entrained by the pressure jet through the emptying pipe 38. During the cleaning of the filter screen 32, the flow through the filter screen 32 increases again with a corresponding pressure reduction until the compression spring 58 moves the filter insert 22 upwards and by closing the outlet through the

Drain pipe 38 the normal flow through the

Filter sieve 32 and the aerator 16 restores.

The embodiment of Figure 4 is both

Water fittings, shower heads, etc., can also be used indefinitely, as is the case with corresponding adaptation in household appliances.

FIG. 5 shows a further embodiment of a self-cleaning filter cartridge according to the invention with automatically or manually controlled cleaning. In the embodiment according to FIG. 5, the filter insert 22 is firmly clamped again between the spacer bush 20 and an inlet disk 62. The closing member consists of an axially movable piston 66 which is guided telescopically in the cylindrical interior 68 of a guide sleeve 64 carried by the run-in disk 62. The piston 66 has an inner, cylindrical piston chamber 70 which is open to the interior 68 of the guide sleeve 64.

The outer end face of the piston 66 is designed as a conical sealing surface 72. In the piston chamber 70 and in the interior 68 of the sleeve 64 there is a compression spring 74, which loads the piston 66 axially downward and presses the sealing surface 72 against the seat formed by the outlet edge in the support basket base 36. The piston wall and the sleeve wall each have radial openings 76, 78, which in closed Align the position of the piston 66 according to FIG. 5. The outside of the opening 78 in the sleeve wall is covered by a sieve 80 which has approximately the same mesh size as the filter sieve 32. An axial pressure equalization channel 82 extends through the end face of the piston 66 and, when the piston position is closed, also the piston chamber 70 connects the drain pipe 38.

5, the piston 66 is closed and forces the water through the sieve 32. However, the fine-mesh sieve 32 causes a slight pressure drop, so that the pressure upstream is slightly higher than that Pressure downstream of the screen. A small proportion of the water also flows through the radial openings 76 and 78 through the piston chamber 70 and through the channel 82, this proportion also being filtered on the strainer 80. Since the filter screens 32 and 80 have approximately the same mesh sizes, approximately the same prevail in the piston chamber 70

Pressure conditions such as downstream of the filter insert 22.

As can be seen from FIG. 5, in the closed position of the piston 66 there is an annular one

Part of the sealing surface 72 above the support basket base 36. This annular surface is accordingly exposed to the pressure on the upstream side, and the force that arises acts on the piston 66 upward against the force of the spring 74 and the pressure in the piston chamber 70 however, calculated so that during normal flow operation and clean sieves, the closing force acting on the piston due to the spring 74 and the pressure in the piston chamber 70 is greater than the opposing opening force on the outer annular surface of the piston 66, so that the piston 66 remains closed. With increasing sieve contamination, the pressure rises upstream, while it falls downstream and in the piston chamber 70, so that the force resulting from this differential pressure is sufficient for a certain degree of contamination to lift the piston 66 from its seat and into the guide sleeve 64 as far as it will go displace (see also FIG. 7), which clears the cleaning pass through the drain pipe 38. This movement of the piston exposes the entire face 72 to the full flow pressure. Since the upward force created by this pressure is stronger than the force of the spring 74, the piston 66 remains open, which means that the cleaning process continues until the water tap is turned off. When the water tap is turned off, the pressure on the end face of the piston falls, so that the piston 66 is displaced into the closed position under the action of the spring 74.

The cleaning process in the embodiment according to FIG. 5 can also be triggered manually at any desired time. To do this, it is sufficient to close the lower outlet of the drain pipe 38, for example with the fingertip, as a result of which the passage through the channel 82 is interrupted. The resulting pressure build-up leads to a pressure equalization between the piston chamber 70 and the drain pipe 38. Since the pressure force on the outer annular surface of the piston 66 above its seat is greater than the sum of the pressure force in the interior 68 of the guide sleeve 64 and the force of the spring 74 , the piston 66 is lifted from its seat. The cleaning process triggered manually in this way can also only be ended by closing the tap.

Figures 6 and 7 show a variant of the embodiment of Figure 5. The operation of this variant is also based on the differential pressure on Piston 66. Instead of creating pressure conditions in the piston chamber 70 via the radial openings 76, 78 and a sieve 80, as in FIG. 5, similar to those downstream of the filter insert 22, the pressure in the embodiment according to FIGS Piston chamber 70 is adapted to the pressure downstream of the filter insert 22 via a by-pass channel 86 leading through the inlet disk 84 and the upper basket rim.

If, due to the blockage of the filter screen 32 and the resulting pressure increase on the outer ring surface of the piston 66 above its seat, the upward force on the piston exceeds the sum of the pressure forces in the interior 68 of the guide sleeve 64 and the force of the spring 74, the piston 66 of lifted his seat and displaced into the open position according to Figure 7. Since the entire end face 72 of the piston 66 is now exposed to the force of the cleaning pressure jet, the piston remains in the open position according to FIG. 7 until the water tap is turned off. The manual triggering of the cleaning process takes place somewhat differently than in the embodiment according to FIG. 5. In the embodiment according to FIGS. 6 and 7 there is an axially movable sleeve 88 in the center of the lower part of the aerator 16, with a sleeve 88 extending through the drain pipe 38 to to the bottom 36 of the filter basket 30 extending pin 90. When this sleeve 88 is pressed in with the fingertip or with any other object, the piston 66 is lifted from its seat from the upper end of the pin and then under the pressure of the water on the entire face displaced into the open position according to FIG. 7.

The embodiment according to FIGS. 6 and 7 responds more quickly when operated manually than in FIG. 5, because in FIG. This can be an advantage places, in particular in the hot water spout, since the cleaning process can be triggered with any object in FIG.

The designs shown in FIGS. 5 to 7 are particularly intended for outlet fittings. On the other hand, they are less suitable for household appliances because the automatically triggered cleaning process continues even after the filter screen has been cleaned until the water tap is turned off, which means that the water supply to the appliance would be eliminated if the cleaning flow as in FIG 3 would be diverted into a sewage hose.

While the exemplary embodiments described above have the common feature that the filter screen is flowed through from the inside to the outside, in the exemplary embodiment described below the filter screen is flowed through from the outside to the inside.

The filter cartridge shown in longitudinal section in FIG. 9 again consists of an approximately cylindrical housing 100 with a thread 102 for screwing onto the outlet of a water tap or a mixer tap. A commercially available aerator 104 and a filter insert 106 according to the invention are seated in the housing.

The filter insert 106 has a cylindrical, fine-mesh filter sieve 108, which forms the outer surface of a filter basket 110 consisting of vertical struts. The filter basket 110 sits on the edge of the central opening 112 of an annular disk 114 above the aerator 104. Above the filter basket 110 there is an inlet disk 116 with a ring of, for example, six inlet openings 118 which open into the annular space around the filter sieve 108. The discs 114, 116 and the filter basket 110 can be made in one piece or consist of separate components. A certain number, for example six, through openings 120 are provided in the housing wall above the disk 114, which openings can be closed by a closing element 122 arranged on the housing periphery. In the exemplary embodiment shown, the closing member 122 has a rotatable sealing ring 124 made of plastic that slides well. The sealing ring 124 has a number of radial and axial outlet openings 126 corresponding to the openings 120 in the housing wall. When the sealing ring 124 is rotated, the annular space around the filter screen can either be connected to the outlet openings 126 or be closed. The rotation of the sealing ring is preferably limited by a radial adjusting screw 130 guided in an arcuate groove 128 on the housing periphery.

As shown, the sealing ring 124 can rest against an annular, conical bead 132 of the housing wall. It is held by means of a rotating sleeve 134 carried by the bead 132, to which the sealing ring 124, e.g. B. is fastened with two screws 138. A between the rotating sleeve 134 and the bead 132 clamping ring 136, z. B. made of rubber, the O-ring, ensures elastic pressure of the sealing ring 134 on the conical bead and sufficient sealing when the closing member 122 is closed.

When the closing member is closed, ie when the outlet openings 126 are rotated relative to the openings 120 in the housing wall, the normal flow takes place through the filter sieve 108, the open filter basket bottom and the air spout 104. When the rotary sleeve 134 is turned manually, Outlet openings 126 are matched to the openings 120 in the housing wall, the water can flow out at full pressure through the outlet openings, the ones in the filter insert 106 deposited dirt particles adhering to the filter sieve 108 are entrained.

The sealing surface between the housing wall and the sealing ring 134 does not have to be absolutely tight. On the contrary, a leakage of the water with increasing pressure in the filter insert 106 due to contamination of the filter sieve 108 and the visible formation of drops on the underside of the closing element 122 can be an indication of contamination of the filter sieve 108 and can encourage the user to put the filter cartridge on the cleaning operation switch.

The filter cartridge according to FIGS. 8 to 10 has the advantage that a commercially available aerator can be used, while the aerators of the previous embodiment must have an opening for the drain pipe. The filter cartridge of FIGS. 8 to 10 is therefore also particularly suitable for taps and mixer taps.

Figures 8a-10a show a variant of the embodiment of Figures 8-10, which is particularly suitable for shower heads in showers. In this embodiment, the housing 100 has a thread 102 or 102a on both sides in order to be screwed, for example, between the mixer tap and the associated spiral hose. This filter cartridge also does not have an aerator because it is superfluous when it is being used. Otherwise, the filter cartridge is identical to that of FIGS. 8-10. In all embodiments and variants, it is possible to easily supplement the hydraulic continuous rinsing of the filter screen by mechanical cleaning of the screen. It can happen that needle-like lime particles crystallize in the water or elongated dirt particles are carried along by the water. Such particles could be in get caught in the fine mesh of the sieve and are not washed away during the cleaning process. In order to prevent this, it is possible to assign an elastic jacket to the filter screen, which lies closely against the screen, but which yields elastically to the water pressure so as not to disturb the passage through the screen.

In the embodiments according to FIGS. 1 to 7, in which the sieve is flowed through from the inside out, the filter basket, e.g. be surrounded by a rubber hose which, when the tap is closed, fits snugly against the outer surface of the filter screen. When the tap is opened, the rubber hose is inflated by the water pressure and frees the entire outer surface of the strainer so that the water can flow through the strainer unhindered during normal flow operation.

When the water tap is closed, the rubber hose snaps together again in a flash, pushing elongated particles stuck in the sieve out of the sieve.

A similar solution can be used in the embodiment according to FIGS. 8-10, in which the screen is flowed through from the outside in. Here, however, an elastic organ would have to be provided on the inner surface of the sieve, which expands through its own elasticity or by means of a spring in order to push out stuck particles outwards and which is compressed by the water pressure in order to free the sieve surface. Such an organ could e.g. B. consist of an annular compressed air hose.

The invention has been described for the sake of simplicity and for better understanding with reference to its use in water pipes. However, the invention is not limited to this special application since the self-cleaning filter cartridge according to the invention if other liquids, such as oil or fuel, or even gaseous media can be used.

A special feature of the filter cartridge according to the invention is that in particular the embodiments of FIGS. 1, 5 and 6 can be switched not only for cleaning purposes, but also whenever a usable water jet with high pressure is required. In the known filter inserts, which serve to generate a gentle water jet, the pressure of the water on the sieve and in the aerator is considerably reduced. However, the present filter cartridge allows at least part of the water to flow out directly through the drain pipe or the outlet openings, the high line pressure when leaving the fitting, e.g. B. can be used for cleaning purposes.

Claims

PATENT CLAIMS

1. Self-cleaning filter cartridge for liquid or gaseous media with an approximately cylindrical housing (10, 100) and an inner filter insert (22, 106), characterized in that the filter insert (22, 106) has a fine-meshed filter screen (32, 108), which forms the outer surface of a cylindrical or frustoconical filter basket (30, 110) and is supported by this in the cartridge housing (10, 100) and is supported in the flow direction and that means are provided to prevent the flow of the liquid or gaseous medium either through the filter screen (32 , 108) or at least partially let it flow out of the filter cartridge along the filter screen (32, 108), the dirt particles adhering to the filter screen (32, 108) being torn away by the flow and pressure and being washed away.

2. Filter cartridge according to claim 1, characterized in that the mesh size of the filter screen (32) is in the order of 100 microns.

3. Filter cartridge according to claim 1 or 2, characterized in that all or individual components consist of a lime-repellent material.

4. Filter cartridge according to one of claims 1 to 3, characterized in that the impermeable bottom of the filter basket (30) is extended downstream by an axial emptying tube (38) that a closing member (40, 60, 66) is present in the filter basket (22) is that the outlet in the emptying pipe (38) seals in normal flow operation, the flow taking place exclusively through the filter sieve (32) and, with the closing element (40, 60, 66) open, most of the flow through the drain ¬ approximately pipe (38).

5. Filter cartridge according to one of claims 1 to 4, characterized in that the housing (10) Has thread (12) in order to be screwed onto the mouthpiece of the outlet opening of a water fitting and that the housing contains an aerator (16) downstream of the filter insert (22).

6. Filter cartridge according to claim 4, characterized in that the emptying pipe (38) opens into a lateral emptying nozzle (54), to which a waste water hose is connected.

7. Filter cartridge according to one of claims 1 to 6, characterized in that the spherical or hemispherical closing member (40) is carried by an elastic spring clip (42) that the spring clip (42) on the one hand in the filter basket (30) attached and on the other hand is connected to a radial driver pin (44) which penetrates the filter screen (32) and is guided in an arcuate slot (46) of the housing (10) and that the driver pin (44) outside the housing in a seal on the housing adjacent rotating ring (48) is anchored.

8. Filter cartridge according to one of claims 1 to 6, characterized in that the closing member (60) is fixed in a stationary and fixed manner to an inlet disk (24), that the filter basket (30) is carried by a compression spring (58) and is elastic in counterflow. direction is pressed against the closing element (60).

9. Filter cartridge according to one of claims 1 to 5, characterized in that the filter insert (22) sits firmly in the housing (10), that the closing member designed as a piston (66) is axially movable in a cylindrical guide sleeve (64) and forms a piston chamber (70) in which a compression spring (74) is arranged, which presses the piston (66) with its conical sealing surface (72) onto the edge of the drain pipe (38), the piston (66) has an axial pressure equalization channel (82) through its sealing surface (72) and means are provided for adjust the pressure in the piston chamber (70) to the pressure on the side downstream of the screen (32).

10. Filter cartridge according to claim 8, characterized gekenn¬ characterized in that the piston wall and the sleeve wall each have a radial opening (76) and (78) which are aligned with each other in the closed piston position and which are closed with a sieve having approximately the same mesh size has, like the filter screen (32).

11. Filter cartridge according to claim 9, characterized gekenn¬ characterized in that the interior (68) of the guide sleeve (64) when the piston position is closed by a by-pass channel (86) extending through the inlet disk (84) and the basket rim (30) ) is connected to the room downstream of the filter insert (22).

12. Filter cartridge according to claim 10, characterized by an in the emptying tube (38) arranged, extending to the filter basket base (36) extending, axially movable pin (90) which can be actuated via a movable sleeve (88) seated in the bubbler (16) is.

13. Filter cartridge according to one of claims 1 to 3, characterized in that the bottom of the filter basket (110) is at least partially open and that the housing wall has closable openings.

14. Filter cartridge according to claim 13, characterized in that the housing wall has a plurality of radial openings (120) which can be opened or closed by means of a rotatable closing member (122) arranged on the outside of the housing.

15. Filter cartridge according to claim 14, characterized gekenn¬ characterized in that the closing member (122) consists of a sealing ring (124) which by means of a rotating sleeve (134) and a clamping ring (136) on an annular bead (132) on the Outside of the housing (100) is held and guided, and the radial openings gen (120) of the housing wall has corresponding radial and axial outlet openings (126).

16. Filter cartridge according to claim 15, characterized gekenn¬ characterized in that the sealing ring (124) has a radial, in an arcuate groove (128) of the housing (100) guided adjusting screw (130), which the rotation of the sealing ring (124) and Limited rotary sleeve (134).

17. Filter cartridge according to one of claims 13 to 16, characterized in that the housing (100) has a thread (102, 102a) on both sides in order to be screwed into the water hose of a shower system.

18. Filter cartridge according to one of claims 1 to 17, characterized in that the filter screen (32,

108) is assigned a jacket which rests elastically or resiliently on the screen surface and is separated from the screen surface by the water pressure during flow operation.