GB2592731A

GB2592731A - Liquid filter

Info

Publication number: GB2592731A
Application number: GB2020366.7A
Authority: GB
Inventors: Arlanzon Lomas David; Jose Tejedor Diago Julio
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-01-20
Filing date: 2020-12-22
Publication date: 2021-09-08
Anticipated expiration: 2040-12-22
Also published as: GB202020366D0; DE102020200589A1; GB2592731B

Abstract

A liquid (e.g. central heating water) filter includes an inner housing 2 having an inlet 6 and outlet 7 and defining an inner space 5, and at least one magnet 8 within the inner space. An outer housing 20 at least partially surrounds the inner housing. The discharge portion 9 of the inner housing includes a discharge opening 10 to enable draining of the inner space, e.g. prior to maintenance/cleaning of the filter. A discharge closure, i.e. drain plug, 11 is externally operable, e.g. by turning of a screw 70 or bayonet closure of the plug, to seal the opening in a fluid-tight manner. When the drain plug is coupled to the discharge opening, i.e. when the opening is sealed by the plug, the outer housing is prevented from being removed from the inner housing. The discharge portion protrudes through a passage opening 21 of the outer housing into an outer surrounding area 30 and/or the drain plug protrudes through the passage opening from the outer surrounding area.

Description

Description Title

Liquid filter

Field of the invention

The invention relates to a liquid filter and a method of dismantling a liquid filter.

Prior Art

Liquid filters for separating magnetic particles are known from the prior art. Such liquid filters are used e.g. in a heating system, e.g. for apartments and apartment buildings, and have hot water flowing through them. In order to prevent wear or damage to circulating pumps, valves or heat C\I exchangers for the hot water, it can be expedient to remove particles, in particular metal particles, from the water. To this end, a liquid filter which has a magnet can be used. Many of the particles can have magnetic properties and can thus be bound to the magnet. (0 20

C Such a liquid filter is known from AT 13751 U1.

Disclosure of the invention

The invention is based upon the knowledge that after a certain period of usage the liquid filer must be cleaned. This can be the case if e.g. a layer of (magnetic) particles has accumulated in the area surrounding the magnet and/or on the bottom of the housing.

It has been shown that it can be expedient to open the liquid filter for cleaning purposes and to rinse out the inner space of the liquid filter or the housing e.g. with running water. In order to perform this cleaning, it is important for safety reasons to separate the liquid filter from the liquid system, e.g. the heating circuit, e.g. by means of valves in its supply line and in its discharge line.

Otherwise, when opening the liquid filter, hot water can continue to flow which could injure the operator. It can be the case that shut-off valves which fluidically separate the liquid filter from the liquid system are not arranged in the vicinity of the liquid filter and/or that the state thereof (open/closed) cannot be seen from the operator's location when dismantling the liquid filter.

In the case of conventional liquid filters which are designed to separate magnetic particles, the C\I housing can be opened to make the inner space accessible (e.g. by unscrewing a housing cover from a housing cup) even if it has been forgotten to close the valves to the liquid system or if the closing procedure was not completed e.g. by reason of defective valves. This can result in many litres of (hot) liquid undesirably passing unhindered in a short period of time into the outer space C\J of the liquid filter.

Therefore, there may be a need to provide a liquid filter, in particular for separating magnetic particles, in which an operator readily recognises if the liquid filter has not yet been separated from the liquid system (e.g. a heating circuit) and which makes at least one intermediate step necessary before the liquid filter or its housing can be opened so that the inner space is accessible for cleaning. The intermediate step can be used to make the operator aware that the liquid filter has not yet been separated from the liquid system, and is used to ensure the safety of the operator and the area surrounding the liquid filter.

Advantages of the invention This need can be met by the subject matter of the present invention according to the independent claims. Advantageous embodiments of the present invention are described in the dependent claims. 3 -

According to a first aspect of the invention, a liquid filter is proposed.

The liquid filter has a housing which encloses an inner space. Furthermore, it has an inlet for a liquid and an outlet for the liquid, at least one magnet arranged at least partially in the inner space and a housing shell which surrounds the housing at least partially on the outside. A discharge opening is provided in the housing in a discharge portion, wherein the discharge opening can be closed in a fluid-tight manner with an externally operable discharge closure. The discharge portion protrudes through a passage opening of the housing shell into an outer surrounding area of the liquid filter. Alternatively or in addition, provision is made that the discharge closure protrudes through the passage opening of the housing shell from the outer surrounding area inwardly to the discharge portion.

In accordance with the invention, provision is made that the discharge closure, in the state when coupled to the discharge opening, prevents the housing shell from being removed from the r housing.

CV

1- This advantageously ensures that the housing shell can be removed from the housing only when 0 the discharge closure is no longer coupled to the discharge opening. This advantageously means (D 20 that, prior to the liquid filter being opened, the discharge closure initially has to be at least C\J partially opened and so the discharge opening is at least partially uncovered. Since the discharge opening preferably has a considerably smaller diameter (smaller at least by a factor of 5) than the diameter of the housing (the opened housing does not constitute the discharge opening), only a relatively small volume flow of the liquid can exit therefrom. If an operator notices that the liquid flow does not stop even after a defined time, then it is likely that the liquid filter is not separated from the liquid system. In this case, the discharge opening can then be closed by means of the discharge closure and/or the liquid filter can be separated from the liquid system. If the operator thus firstly wishes to remove the housing shell before he opens the housing (e.g. this sequence can be specified by operating instructions or on a printed label on the liquid filter), then he must initially decouple or release the discharge closure from the discharge opening and thus advantageously he can become aware relatively safely that the liquid filter is not yet separated from the liquid system.

The housing shell can be formed e.g. in the shape of a cup. It can surround the housing, at least in portions or partially, like a second housing wall. 4 -

The liquid container can be suitable for separating magnetic particles. It can also be designed to separate magnetic particles or to bind same from the liquid. Magnetic particles are to be understood to be those particles which can be attracted by a magnet, e.g. a permanent magnet or an electromagnet.

Within the scope of the application, the expression "having" is used synonymously with the expression "comprising", unless otherwise described.

The housing can be formed in the shape of a cup. It can be closed with a cover. The housing can be e.g. hollow-cylindrical. It can extend along a longitudinal axis. The longitudinal axis can be an axis of symmetry of the housing. The longitudinal axis can extend from a bottom of the housing to the cover. The longitudinal axis can define an axial direction.

A radial direction is perpendicular to the direction of the (longitudinal) axis. A circumferential direction is circumferential to the direction of the (longitudinal) axis.

C

In one development, provision is made that it is rendered more difficult to open the housing when the housing shell is mounted. The difficulty relates to a state in which the housing shell is not (0 20 mounted on the housing or in which it does not surround the housing.

As a result, the delay effect when opening the housing is advantageously achieved or extended. As a result, the operator gains time in a particularly reliable manner in order to observe or establish whether the liquid filter is separated from the liquid system. This is because, in order to dismantle the housing shell, the discharge closure must initially be decoupled from the discharge opening, as a result of which the liquid flow out of the discharge opening can be observed. This allows the operator to recognise, before the housing of the liquid filter is opened, whether an unusually strong liquid flow is exiting from the discharge opening (e.g. by reason of high pressure in the liquid system) or whether the exiting liquid flow is continuing for an unusually long time.

Any Inadvertent, excessively rapid opening of the housing directly after releasing the discharge closure or even without releasing the discharge closure is advantageously prevented. It is only after the discharge closure has been released or decoupled from the discharge opening that initially the housing can be removed and subsequently the housing can be opened. -5 -

For example, provision can be made that, in a state in which the housing shell is mounted on the housing, a closure element of the housing is e.g. not freely accessible or is (mechanically, electrically or magnetically) blocked or covered or cannot be actuated directly.

This can advantageously ensure that the housing of the liquid filter or the closure element of the housing can be opened in a simple manner only when the housing shell has been removed from the housing. Therefore, the closure element (e.g. a screw connection or a bayonet closure or a clip closure, etc.) is only freely or easily accessible or can be directly actuated if the housing shell is dismantled from the housing. For example, the housing shell can prevent direct engagement at both ends of a screw connection or bayonet connection such that the screw connection or bayonet connection cannot be released or can only be released in a laborious manner.

In one development, provision is made that the discharge closure is formed with a screw. This advantageously produces a discharge closure which can be produced in a particularly cost-effective and simple manner. Particularly effective sealing tightness is also advantageously achieved. Finally, in this manner the opening of the discharge opening can advantageously be C\I controlled in a particularly precise manner and therefore the volume flow out of the discharge opening can be controlled.

Alternatively or in addition, the discharge closure can be formed with a bayonet closure. This C\J advantageously ensures particularly rapid opening and closing of the discharge opening.

Furthermore, this can advantageously ensure that only the appropriate discharge closure is mounted on the housing. In this manner, any bypassing of the securing arrangement of the housing shell which stops premature removal is prevented (it is not possible e.g. to simply insert another screw which does not block the housing shell). Therefore, a type of poka-yoke effect is produced.

Alternatively or in addition, the discharge closure can be formed with a clip connection. This advantageously ensures particularly rapid opening and closing of the discharge opening.

Furthermore, this can advantageously ensure that only the appropriate discharge closure is mounted on the housing. In this manner, any bypassing of the securing arrangement of the housing shell which stops premature removal is prevented. In a further advantageous manner, the discharge closure can thus be formed e.g. like a swing top of a beer bottle and can thus be captively fastened to the housing. The securing effect in relation to the housing shell can be achieved by virtue of the fact that the discharge closure has different cross-sectional profiles in -6 -the axial and radial direction. In the released state, it can be possible e.g. to thread the discharge closure through the passage opening of the housing shell.

It is understood that the discharge closure can also be coupled or is coupled in a different manner to the discharge opening.

By virtue of the fact that the housing shell is releasably fastened to the housing, it is advantageously ensured that, after release or even removal of the discharge closure from the discharge opening, the housing shell is not automatically released from the housing but instead is held initially on the housing. As a result, an operator can dismantle the liquid filter advantageously in his own time.

For example, provision can be made that the housing shell is attached to the housing by means of a clip connection and/or by means of a latching connection and/or by means of a screw connection and/or by means of a bayonet connection. In a particularly advantageous manner, the passage opening of the housing shell is aligned with the discharge portion or the discharge opening in a state in which the housing shell is mounted on or attached to the housing.

The term "releasable" is to be understood to mean that a connection can be released in a non-CO 20 destructive manner.

In one development, provision is made that the housing has a pocket which protrudes into the inner space, wherein the magnet is fastened to the housing shell, wherein, in a state in which the housing shell is mounted on the housing, the magnet is arranged in the pocket. In an advantageous manner, this ensures that the magnet as such does not come directly into contact with the liquid but instead is separated from the liquid by means of a pocket wall of the pocket. This minimises the risk of the magnet becoming fouled by particles or the risk of corrosion as a result of contact with the liquid. In a further advantageous manner, the cleaning can thereby be significantly simplified. The reason for this is that particularly strong permanent magnets bind magnetic particles very strongly thereto and so it would be difficult and laborious to clean the magnetic particles from a permanent magnet covered with such particles. In a further advantageous manner, this arrangement advantageously ensures that an operator has an incentive to initially remove the housing shell before he opens the housing. In this manner, his safety is increased because he must decouple the discharge closure from the discharge opening prior to removal of the housing shell. Finally, this advantageously ensures that, after the end of -7 -maintenance of the liquid filter, the housing shell is then mounted therewith because the magnet is fastened to the housing shell. Therefore, an operator -if he does not wish to leave the magnetic particle separation procedure inoperative -cannot simply leave the housing shell off in order to reduce the dismantling steps for the next maintenance procedure. This is because then it would not be possible to arrange the magnet securely in the inner space of the housing.

For example, provision can be made that the magnet is releasably fastened to the housing shell, e.g. by means of a screw connection or a fastening screw. As a result, in the case of a defective magnet or a defective (e.g. broken) housing shell, the respective still intact element can be re-used.

In one development, provision is made that the housing has a first housing part and a second housing part, wherein the first housing part and the second housing part are connected to one another in a fluid-tight manner (in particular in the mounted state of the liquid filter). As a result, particularly simple dismantling or maintenance or cleaning of the liquid filter is advantageously effected. The first housing part can be designed e.g. as a cover or a cover element. The second C\I housing part can be designed e.g. as a housing cup. It can have e.g. a bottom. In the mounted state, the inner space of the housing which can be formed by both housing parts is separated in a fluid-tight manner from an outer space of the liquid filter. (0 20

C\J The first housing part and the second housing part can be connectable or connected to one another e.g. by means of a screw connection and/or a bayonet closure and/or a clip connection and/or by means of a latching connection. In a particularly preferred manner, the first and second housing parts are connectable or connected to one another in a releasable manner (i.e. non-destructively separable from one another).

In an advantageous manner, provision is made that the inlet and the outlet are arranged on the first housing part, wherein the discharge portion is arranged on the second housing part. As a result, a spatial and functional separation is advantageously effected between the components for the normal operation (inlet and outlet) and for the purpose of maintenance (releasing the discharge closure). This also renders it possible to use e.g. the second housing part for different first housing parts and thus to achieve a cost-effective modular design.

For example, provision can be made that the second housing part is arranged, in a normal installation position of the liquid filter in relation to the gravitational force (g), under the first -8 -housing part. This ensures that the discharge opening is arranged at a most geodetically lowest possible point. As a result, during dismantling of the housing it is advantageously possible to ensure that liquid is emptied in the most complete manner possible from the inner space of the housing before the housing is opened.

By virtue of the fact that the discharge closure, in a state in which it closes the discharge opening in a fluid-tight manner, is oversized in relation to the passage-opening of the housing shell, it is advantageously ensured that with particularly simple and cost-effective means the housing shell cannot be removed from the housing as long as the discharge closure is coupled to the discharge opening.

It is understood that such an oversize of the discharge closure is not essential for securing the housing shell. It is feasible that the discharge closure, in the state when closed in a fluid-tight manner, activates a blocking element (mechanically and/or electrically and/or magnetically) which prevents removal of the housing shell. This can be e.g. by locking bar elements or a splaying element in the form of a dowel pin or the activation of a magnetic closure.

C

According to a second aspect of the invention, a method of dismantling a liquid filter is proposed. The term dismantling is to be understood to mean that, after the dismantling, the inner space of (0 20 the housing is freely accessible in order e.g. to be cleaned (the mere opening of the discharge C\J opening thus does not bring about any dismantling).

The method of dismantling a liquid filter comprises at least the steps of: * providing a liquid filter, as described above; * releasing the discharge closure from the discharge opening; * removing the housing shell from the housing, in particular after the liquid filter has become empty; * opening the housing.

The method advantageously ensures that the housing is opened only when beforehand the discharge closure has been released from the discharge opening and subsequently the housing shell has been removed. As a result, the operator gains time in order to inspect the liquid flow flowing out of the discharge opening and to recognise whether the liquid filter has been correctly separated from the liquid system. 9 -

In one advantageous development, between the step of releasing the discharge closure and the step of removing the housing shell a further step can also be provided: * removing the discharge closure from the housing.

In one advantageous development, between the step of releasing the discharge closure and the step of removing the housing shell, still further steps (individually or in combination) can also be provided: * detecting or observing how strongly and/or how long the liquid flow flows out of the discharge opening -this can be effected e.g. by means of electronic sensors; * comparing the detected or observed values to desired values (e.g. from a group of characteristics) -this can be effected e.g. by means of a computer; * in dependence upon the comparison: establishing whether the liquid filter is completely fluidically separated from the liquid system -for this purpose, e.g. tolerance intervals around the desired values can be specified; * if it is established that the liquid filter is not completely separated from the liquid system: interrupting the dismantling and/or the separation of the liquid filter from the liquid system; alternatively, if the detected value is outside the tolerance interval, e.g. an error (0 20 message can also be output.

This advantageously permits maintenance, which is particularly safe for the operator and the surrounding area, with a reproducible method.

Drawings Further features and advantages of the present invention will become apparent to the person skilled in the art from the following description of embodiments by way of example which, however, are not to be interpreted as limiting the invention, with reference to the accompanying drawings.

In the drawings: Figure 1: shows a schematic view of a liquid filter; -10 -Figure 2: shows a schematic cross-section of a further liquid filter; Figures 3a to Sc: show detailed views of the liquid filter of figure 2 in various states during dismantling; Figure 4: show steps of a method of dismantling a liquid filter.

Figure 1 shows a schematic cross-section of a liquid filter 1. The liquid filter 1 is suitable for separating magnetic particles 60. It can also be designed to separate magnetic particles 60. The liquid filter 1 can be used e.g. in a heating system for apartments or houses.

The liquid filter 1 has a housing 2 which encloses an inner space S. Furthermore, it has an inlet 6 for a liquid and an outlet 7 for the liquid (it is understood that the inlet 6 and outlet 7 can basically also be interchanged). Furthermore, it has at least one magnet 8 arranged at least partially in the inner space, and a housing shell 20 which surrounds the housing 2 at least partially on the outside. A discharge opening 10 is provided in the housing 2 in a discharge portion 9, wherein the C\I discharge opening 10 can be closed in a fluid-tight manner with an externally operable discharge closure 11. In this exemplified embodiment, provision is made that the discharge closure 11 protrudes through a passage opening 21 of the housing shell 20 from an outer surrounding area 30 of the liquid filter 1 inwards to the discharge portion 9. The discharge closure 11, in the state C\J when coupled to the discharge opening 10, prevents the housing shell 20 from being removed from the housing 2.

The housing 2 extends along a longitudinal axis A. A radial direction R is perpendicular to the longitudinal axis A. A circumferential direction U is circumferential to the longitudinal axis A. In this case, the housing 2 and/or the housing shell 20 is made by way of example from a material which has a main portion (more than 50%) consisting of synthetic material. It can be formed e.g. from polyamide (PA) or can comprise polyamide, e.g. polyamide filled with glass fibres (e.g. PA66).

Polypropylene (PP) is also possible. A structure made from synthetic material is particularly cost-effective. A different synthetic material is basically also possible. A use of metal or a formation exclusively consisting of metal is also feasible. The wall thicknesses of the housing 2 and/or housing shell 20 can be e.g. in each case at least 2 mm, preferably at least 4 mm.

The liquid can be e.g. water or hot water, e.g. at a temperature which is at least 30, preferably at least 40°C, particularly preferably at least 50°C most particularly preferably at least 60°C.

The liquid from a liquid system (e.g. a heating circuit), not illustrated in this case, can enter the inner space 5 of the housing 2 via a supply line 40 and the inlet 6. The magnetic particles 60 contained in the liquid can then be attracted by the magnet 8 and fixedly held thereon and are thus separated from the liquid. The liquid thus cleaned can leave the inner spaces of the housing 2 via the outlet 7 and passes back into the liquid system via the discharge line 50. In order to permit safe dismantling and cleaning or maintenance of the liquid filter 1, the liquid filter 1 can be fluidically separated from the liquid system. For this purpose, a supply line valve 41 is provided in the supply line 40 and a discharge valve 51 is provided in the discharge line 50. The liquid filter 1 is to be dismantled or its housing 2 opened only if the supply line valve 41 and the discharge valve 51 are closed and the liquid filter 1 is thus fluidically separated from the liquid system. It is understood that the inlet 6 and outlet 7 can basically also be interchanged -then the supply line 40 with the supply line valve 41 and the discharge line 50 with the discharge valve 51 are interchanged.

The discharge opening 10 has a considerably smaller diameter than the diameter of the housing 2. For example, the diameter of the housing 2 is at least three times as large, preferably at least five times as large, as the diameter of the discharge opening 10. By means of the discharge opening 10 C\J and the strength and/or duration and/or temperature of a liquid flow flowing therethrough when the discharge closure 11 is open, it is possible to safely establish whether the liquid filter 1 is completely separated from the liquid system.

In this case, the housing 2 has a first housing part 3 and a second housing part 4. The first housing part 3 can be e.g. a housing cover. The second housing part 4 can be e.g. a housing cup having a bottom. The first housing part 3 and the second housing part 4 are connected to one another in a fluid-tight manner when the liquid filter 1 is in the mounted state. In this exemplified embodiment, a screw connection is provided as a closure means 78 of the housing 2. A bayonet closure or a different connection can also be provided.

In the figure, the direction of the gravitational force g is indicated pointing downwards. Therefore, in figure 1 the discharge opening 10 is located approximately at the geodetically lowest point. In this manner, during dismantling almost all of the liquid located in the inner spaces is discharged via the discharge opening 10.

-12 -Furthermore, the housing 2 has a ventilation element 17 at its geodetically approximately highest point. By means of this ventilation element 17, e.g. formed as a screw, e.g. air or gaseous media which have accumulated in the inner space Scan be discharged from the inner space 5 and thus removed.

In this embodiment, the discharge closure 11, in a state in which it closes the discharge opening 10 in a fluid-tight manner, is oversized in relation to the passage-opening 21 of the housing shell 20. As a result, when the discharge closure 11 is mounted, the housing shell 20 cannot be removed from the housing 2. However, other embodiments are also feasible, by means of which the housing shell 20 is fixedly held on the housing 2 when the discharge closure 11 is in the mounted state. This can be e.g. by mechanical, electrical or magnetic devices, e.g. the mechanical actuation of locking bar elements, splaying in the manner of a dowel pin, an electrically actuated closure or a magnetic holder. Other types of fixing are also feasible.

In this case, in a state in which a housing shell 20 is mounted on the housing 2, the closure C\I element 78 of the housing 2 is not freely accessible or is blocked or covered or cannot be directly actuated. However, this is not an essential element of the invention. Therefore, opening the housing 2 when the housing shell 20 is mounted is rendered more difficult in this embodiment (0 20 which is provided merely by way of example. Therefore, an operator cannot readily release the C\J second housing part 4 from the first housing part 3 without having previously removed the housing shell 20-he at least becomes aware that the proposed dismantling procedure is to be adhered to. The removal of the housing shell 20 is, in turn, only possible if previously the discharge closure 11 is released or decoupled or removed from the discharge opening 10.

The housing shell 20 can be releasably fastened to the housing 2, e.g. by means of a clip connection and/or a latching connection and/or by means of a screw connection and/or by means of a bayonet connection. As a result, even when the discharge closure is released or removed, the housing shell 20 is held independently on the housing 2.

In this case, the discharge closure 11 can be formed with a screw which engages into a thread of the discharge opening 10 or is screwed onto an external thread of the discharge opening 10. Alternatively or in addition, the discharge closure 11 can be formed with a bayonet closure. Alternatively or in addition, it can be formed with a clip connection.

-13 -Figure 2 shows a schematic cross-section of a further liquid filter 1.

In this embodiment, the housing 2 has a pocket 12 which protrudes into the inner space 5. In this case, the magnet 8 is fastened to the housing shell 20, e.g. by means of a screw connection with a fastening screw 75 which can be released in a non-destructive manner. The fastening screw 75 can be formed e.g. in one piece with the housing shell 20. It can engage into a recess, which is structured having a thread, at a distal end of the magnet 8. In a state in which the housing shell 20 is mounted on the housing 2, the magnet 8 is arranged in the pocket 12. It is inserted into the pocket 12 through a pocket opening 19 which faces downwards in figure 2. It is separated from the liquid in the inner space 5 by means of a pocket wall 73.

In this embodiment by way of example, the inlet 6 and the outlet 7 are arranged on the first housing part 3 and the discharge portion 9 is arranged on the second housing part 4. The second housing part 4 can preferably be arranged, in a normal installation position of the liquid filter 1 in relation to the gravitational force g, under the first housing part 3. r

CV In this embodiment by way of example, the discharge portion 9 protrudes through a passage- 1- opening 21 of the housing shell 20 into the outer surrounding area 30 of the liquid filter 1. This 0 ensures -by reason of the eccentric arrangement of the discharge portion 9 in relation to a (D 20 central axis of the housing 2-that the housing shell 20 is always in a true position.

CV

In this case, the first housing part 3 has, between the inlet 6 and outlet, a fluid guide wall 18 which extends in the inner space 5 of the housing 2 approximately in parallel with the (longitudinal) axis A downwards to the second housing part 4. This fluid guide wall 18 can impose on the liquid entering through the inlet 6 into the inner space 5 a rotatory component in the circumferential direction U. In this manner, particles (magnetic or non-magnetic) contained in the liquid can be urged by means of a cyclone effect (centrifugal separation) to the outer side of the inner space 5 where they settle. This improves the purity of the liquid which is recirculated from the outlet 7 into the liquid system. It is understood that the supply line 6 and discharge line 7 can basically be interchanged.

The housing shell 20 can be held on the second housing part 4 e.g. by means of a clip connection 22. The first housing part 3 and second housing part 4 can be connected to one another in a fluid-tight manner e.g. by means of a screw connection as a closure element 78, wherein a sealing -14 -means 16, e.g. in the form of an 0-ring, improves the sealing tightness. The housing shell 20, when in the state mounted on the housing 2, can block any release of the screw connection.

The discharge connection 11 has a screw 70 and a cup 71 which is arranged around the screw 70.

The cup 71 can capture any liquid exiting the discharge opening 10. Arranged at the bottom of the cup 71 is an outlet nozzle 72, through which the captured liquid can be discharged in a targeted manner, e.g. into a bucket.

Figure 3a shows a first detailed view of the liquid filter of figure 2 in a first state during dismantling. The discharge closure 11 has been decoupled from the discharge opening 10 and has been removed from the housing 2. The housing shell 20 is still fastened to the second housing part 4 by means of the clip connection 22 (other releasable connections are also possible). In this state, the liquid located in the inner space 5 can run off through the discharge opening 10. It is not yet (directly or readily) possible to open the housing 2 because the closure element 78 of the housing 2 is still blocked or covered by the housing shell 20 (an operator could only grasp hold of the housing shell in order to rotate the second housing part 4 with respect to the first housing C\I part 3 -however, it is then not possible or in any event not so easily possible to open the housing part 2). In other words, in the illustrated screw connection between the first housing part 3 and second housing part 4, the lower end of the screw connection in the figure is not freely accessible.

CD 2 0 C By observing or detecting volume flow and/or duration and/or temperature of the liquid flow, it is possible to conclude whether the liquid filter 1 is fluidically completely separated from the fluid system. This can be particularly relevant e.g. when the shut-off valves cannot easily be accessed or seen or are not located in the immediate vicinity of the liquid filter 1.

If the liquid flow is unusually strong and/or long-lasting and/or the temperature corresponds to that of the liquid system, this can be an indication that the liquid filter 1 is not yet fluidically completely separated from the liquid system. In this case, it can be necessary e.g. to check and/or completely close the shut-off valves. Alternatively or in addition, the dismantling procedure can be interrupted. For example, the discharge closure 11 can then be coupled to the discharge opening 10, e.g. by turning the screw 70. Grasping hold of the edge of the cup 71 or the outlet nozzle 72 allows this procedure to be performed even in the case of hot liquids without a high risk of burning.

-15 -Figure 3b shows a second detailed view of the liquid filter of figure 2 in a second state during dismantling. The housing shell 20 with the magnet 8 fastened thereto has been released from the housing 2. Therefore, particles 60 (not illustrated here) held magnetically in the inner space Scan now be easily released from the pocket wall 73. Moreover, the housing 2 can now be opened. The closure element 78 of the housing 2 is open in an unblocked manner. In other words: If an operator grasps hold of the second housing part 4 and rotates it relative to the first housing part 3, this movement is transmitted into the closure element 78, in this case the screw connection, which was not yet the case in the state shown in figure 3a.

Figure 3c shows a third detailed view of the liquid filter of figure 2 in a third state during dismantling. The housing 2 is now open and the second housing part 4 has been unscrewed from the first housing part 3. The second housing part 4 in which the separated particles accumulate can now be cleaned. Subsequently, the liquid filter 1 can then be mounted or put back together in the reverse order.

Figure 3c clearly shows the fluid guide wall 18. C\I

Figure 4 shows steps of a method of dismantling a liquid filter 1. The method includes, along the solid line, the steps of: (0 20 C * providing 100 a liquid filter 1, as described above; * releasing 200 the discharge closure 11 from the discharge opening 10; * removing 300 the housing shell 20 from the housing 2, in particular after the liquid filter 1 has become empty; * opening 400 the housing 2.

Still further steps can be provided between the steps of releasing 200 the discharge closure 11 and removing 300 the housing shell 20. They can be e.g. the following steps, all of which or individual ones of which are performed: * removing 250 the discharge closure 11 from the housing 2; * detecting or observing 260 how strongly and how long the liquid flow flows out of the discharge opening 10; * comparing 270 the detected or observed values to desired values e.g. from a group of characteristics; -16 - * in dependence upon the comparison: establishing 280 whether the liquid filter 1 is completely fluidically separated from the liquid system; * if it is established that the liquid filter 1 is not completely separated from the liquid system: interrupting 290 the dismantling and/or separation of the liquid filter 1 from the liquid system.

The liquid filter land the method of dismantling the liquid filter 1 are suitable e.g. for use in heating circuits, e.g. for apartments and houses, wherein the heating circuits are operated e.g. with hot water, wherein particles, in particular magnetic particles 60, are to be separated out of the liquid. However, the liquid filter land the method are not limited to such applications.

Claims

-17 -Claims 1. Liquid filter, in particular for separating magnetic particles, the liquid filter having: --a housing (2) which encloses an inner space (5); --an inlet (6) for a liquid; --an outlet (7) for the liquid; --at least one magnet (8) arranged at least partially in the inner space (5); --a housing shell (20) which surrounds the housing (2) at least partially on the outside; wherein a discharge opening (10) is provided in the housing (2) in a discharge portion (9), wherein the discharge opening (10) can be closed in a fluid-tight manner with an externally operable discharge closure (11), wherein the discharge portion (9) protrudes through a passage opening (21) of the housing shell (20) into an outer surrounding area (30) of the liquid filter (1), C\I and/or wherein the discharge closure protrudes through the passage opening (21) of the housing shell (20) from the outer surrounding area (30) inwards to the discharge portion (9), (0 20 wherein the discharge closure (11), in the state when coupled to the discharge opening C\J (10), prevents the housing shell (20) from being removed from the housing (2).
2. Liquid filter as claimed in the preceding claim, wherein it is rendered more difficult to open the housing (2) when the housing shell (20) is mounted, wherein, in particular in a state in which the housing shell (20) is mounted on the housing (2), a closure element (78) of the housing (2) is not freely accessible or is blocked or is covered or cannot be actuated directly.
3. Liquid filter as claimed in any one of the preceding claims, wherein the discharge closure (11) is formed with a screw and/or wherein the discharge closure (11) is formed with a bayonet closure and/or wherein the discharge closure (11) is formed with a clip connection.
-18 - 4. Liquid filter as claimed in any one of the preceding claims, wherein the housing shell (20) is releasably fastened to the housing (2), in particular by means of a clip connection (22) and/or a latching connection and/or by means of a screw connection and/or by means of a bayonet connection.
5. Liquid filter as claimed in any one of the preceding claims, wherein the housing (2) has a pocket (12) which protrudes into the inner space (5), wherein the magnet (8) is fastened, in particular releasably fastened, to the housing shell (20), wherein, in a state in which the housing shell (20) is mounted on the housing (2), the magnet (8) is arranged in the pocket (12).
6. Liquid filter as claimed in any one of the preceding claims, wherein the housing (2) has a first housing part (3) and a second housing part (4), wherein the first housing part (3) and the second housing part (4) are connected to one another in a fluid-tight manner, C\I in particular by means of a screw connection or a bayonet closure.
CD 7. Liquid filter as claimed in the preceding claim, (0 20 wherein the inlet (6) and the outlet (7) are arranged on the first housing part (3), C\J wherein the discharge portion (9) is arranged on the second housing part (4), wherein in particular the second housing part (4) is arranged, in a normal installation position of the liquid filter (1) in relation to the gravitational force (g), under the first housing part (3).
8. Liquid filter as claimed in any one of the preceding claims, wherein the discharge closure (11), in a state in which it closes the discharge opening (10) in a fluid-tight manner, is oversized in relation to the passage opening (21) of the housing shell (20).
9. Method of dismantling a liquid filter, comprising the steps of: --providing (100) a liquid filter (1) as claimed in any one of the preceding claims; --releasing (200) the discharge closure (11) from the discharge opening (10); --removing (300) the housing shell (20) from the housing (2), in particular after the liquid filter (1) has become empty; -19- --opening (400) the housing (2).