Inner filter for aquarium

An inner filter for an aquarium has means forming a pump chamber, a filter chamber, a suction opening, and outlet opening, a suction passage which communicates with the pump chamber and the filter chamber and in which water is aspirated through the suction opening, a pressure chamber which communicates with the pump chamber and the outlet opening, a pump wheel, an electric motor having a rotor which drives the pump wheel in the pump chamber and also having a stator and a housing having three releasable and again assembleable segments, the segments including a first segment which accommodates the stator with an electric conductor, a second segment which accommodates the rotor with a bearing axles and bearings and also accommodates the pump wheel, the pump chamber, the filter chamber, the suction passage and the pressure passage, and a third segment which is placeable on the second segment and formed as a cover and has the outlet opening connectable with the pressure passage, the suction opening which is connectable with the filter chamber being provided in the region of one of the third segment and the first segment.

BACKGROUND OF THE INVENTION 
The present invention relates to inner filters for an aquarium with an 
electric motor operating to circulate water in the aquarium. 
An inner filter of this type is disclosed for example in the German 
document DE-GM 81 26 762.2. It is substantially rod-shaped and has an 
upper pump head which is closed with a cover and accommodates the complete 
electric motor with a stator and a rotor as well as their bearing axles 
and bearings for a pump wheel rotated by the rotor. The pump head is also 
provided with a pump chamber and a pressure passage. The electric motor 
with its components is fixedly installed in the pump head. The pump 
chamber and the pump wheel arranged in it are located under the stator and 
the rotor. A housing part is arranged under the pump head and has a 
central suction passage which is coaxial to the rotor and can be defined 
for example by a pipe provided with openings. At least one filter insert 
is mounted on the pipe. The housing part which contains the filter insert 
is provided with openings in its wall for suction of water so that the 
water can be sucked through the filter insert into the central pipe which 
forms the suction passage. From there the water is supplied by the pump 
through the pump chamber into the pump head and from the pump head in the 
pressure passage located in it. Through the pressure passage the water is 
guided upwardly until it exits from an upwardly located outlet opening 
from the pump head. In this inner filter the lower end of the bearing axle 
is held in a special bottom part which is placed from below and releasably 
on the pump head and which is located between the pump head and the 
housing part located under it and containing the filter insert. When it is 
necessary to clean this known inner filter, it must be removed from the 
aquarium tank as a whole and then dismounted. For exchanging the filter 
insert the lower tubular housing part can be withdrawn. When, however, for 
example the pump wheel, the neighboring region of the rotor, the region of 
the pump chamber or the pressure passage must be cleaned, then first the 
bottom-side closure of the pump head must be released and removed. Then 
the rotor with the bearing axle and the bearings must be disassembled in 
its individual components so that an assembly problem takes place. 
Moreover, the individual regions even with the removed rotor with the pump 
wheel are difficult to access and therefore difficult to clean. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an inner 
filter for an aquarium of the above mentioned type, which avoids the 
disadvantages of the prior art. 
More particularly, it is an object of the present invention to provide an 
inner filter for an aquarium which is designed so that it can be 
dismounted fast and simple by a user without special knowledge and 
auxiliary tools, a filter insert located in the filter chamber can be 
exchanged fast and without difficulties, and the remaining functional 
parts of the inner filter are well accessible for cleaning, maintenance 
and repairs. 
In keeping with these objects and with others which will become apparent 
hereinafter, one feature of the present invention resides, briefly stated, 
in an inner filter for an aquarium which has three releasable and 
assembleable segments, with a first segment which contains the stator with 
the electrical conductor, a second segment which contains substantially 
the rotor with the bearing axle and bearings as well as the pump wheel, 
the pump chamber and the filter chamber and the suction passage as well as 
the pressure passage, and a third segment which is formed as a cover 
located on the second segment and closing the second segment and which has 
at least one outlet opening connectable with the pressure passage, wherein 
a suction passage connectable with the filter chamber is provided in the 
region of the third segment or the first segment. 
When the inner filter is designed in accordance with the present invention 
it avoids the disadvantage of the prior art and provides for the above 
mentioned advantages. 
Due to the subdivision of the inner filter into the three releasable and 
assembleable segments, with the first segment substantially containing the 
stator with the electrical conductor, it is possible for example for 
exchanging the filter insert or for cleaning and maintenance works to 
release the third and the second segments, while the first segment can 
remain as before inside the aquarium container at a predetermined 
position. The released second and third segments can be removed from the 
tank and cleaned when needed. When it is only necessary to exchange the 
filter insert, only the third segment must be withdrawn, so that the upper 
end of the second segment is released for withdrawing of the filter 
insert. The filter insert can be removed fast and without difficulties 
upwardly, and there is no danger that some dirt particles which adhere to 
the filter insert can remain in the aquarium tank. When also a cleaning of 
for example the third segment or also the second segment must be 
performed, both segments must be withdrawn from the tank while the first 
segment remains in the aquarium tank, they are cleaned and again inserted 
into the tank. This can be performed by a user without special expert 
knowledge and special tools fast and without difficulties. 
The novel features of the present invention which are considered as 
characteristic for the invention are set forth in particular in the 
appended claims. The invention itself, however, both as to its 
construction and its method of operation, together with additional objects 
and advantages thereof, will be best understood from the following 
description of specific embodiments when read in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An inner filter in accordance with the present invention is identified as a 
whole with reference numeral 10. It can be formed for example as a 
miniature filter which is suitable for example for an aquarium of up to 60 
liter. The inner filter 10 is inserted in an aquarium tank 11 as shown in 
FIG. 3. It is releasably mounted with its rear side 12 on the associated 
inner side 13 of an aquarium wall 14 by means of suitable holders 15, for 
example suction members. The water level in the aquarium tank 11 is 
identified with reference numeral 16 in FIG. 3. It can be seen that the 
inner filter 10 is correspondingly deep in order to exchange water which 
is located in the aquarium tank 11. 
The inner filter 10 has an electric motor 17. The electric motor as well 
known has a stator 11 and a rotor 19 and is supplied with current through 
an electrical conductor 20 extending upwardly from the aquarium tank. The 
electric motor 17 can be of a conventional type, for example a 
self-starting synchronous motor with a permanently magnetic rotor 19 which 
for example has two or several poles and is radially polarized. The 
magnetic poles with alternating polarity can be uniformly distributed 
around the rotor periphery. The rotor 18 is located in a passage 21 of the 
stator 18 so as to form the required air gap. The rotor 19 is held on a 
one-piece or two-pieces bearing axle 22 and rotatable so as to run 
substantially vertically. It is supported with its both ends in associated 
bearings 23 and 24 which can composed for example of elastic elements, for 
example, rubber lips. The rotor 19 drives a pump wheel 25 of a pump, which 
is located above the rotor 19 and in a pump chamber 26 and formed for 
example as multi-vane element. 
The inner filter 10 has further a suction passage which is identified as a 
whole with reference numeral 30. It communicates with the pump chamber 26 
at one side and with a filter chamber 31 which is located in the inner 
filter 10 upstream of the suction passage. When the pump wheel 25 rotates, 
water is aspirated from the aquarium tank 11 into the filter chamber 31 
through at least one outwardly open aspiration opening 32 which is located 
under the water level 16, as identified with an arrow 33 in FIG. 2. At 
least one schematically shown filter insert 34 can be accommodated in the 
filter chamber 31 and composed of a filtering material, for example of 
foam material or other suitable filtering material, activated coal, etc. 
The filter insert 34 is shown schematically as a suspended, upwardly 
withdrawable four-cornered block. The aspirated water passes in 
correspondence with the arrows in FIGS. 2 and 3 through the filter insert 
34 through its total vertical dimension or at least through a substantial 
part of the vertical dimension transversely. Then the water after passing 
the filter insert 34, the suction passage 30 and the pump chamber 25 flows 
into a pressure passage 40. The pressure passage communicates with the 
pump chamber 26 on the one hand and with at least one outlet opening on 
the other end, so that the water exits through the outlet opening in 
correspondence with the arrows in FIGS. 2 and 3 from the inner filter 1 
and then again supplied back into the aquarium tank 11. The inner filter 
10 is located in the water of the aquarium tank so deep that 
advantageously at least one outlet opening 41 is located above the water 
level 16. 
A further special feature of the inner filter 10 is that it is composed of 
three releasable and again assembleable, for example pluggable-in segments 
50, 60 and 70. The segments are designed so that when needed they can be 
separated from one another by a user as shown for example on the explosive 
view of FIG. 1. As a rule, the first segment 50 remains inside the 
aquarium tank 11 and is therefore releasably mounted on the aquarium wall 
14, while only the second segment 60 and the third segment 70 can be 
withdrawn upwardly from the first segment 50, as will be explained 
hereinbelow. 
The first segment 50 is substantially L-shaped. Its shortest L-leg 51 
extends forwardly and can be placed on the second segment 60 in a vertical 
direction from above. The first segment 50 contains substantially the 
stator 18 of the electric motor 17 with the electrical conductor 20 and 
forms a part which can be mounted with its rear side 12 releasably on the 
aquarium wall 14. For example for cleaning the inner filter 10 it can 
remain in the fixedly mounted position in the tank as shown in FIG. 3. 
The second segment 60 is designed so that it contains substantially the 
rotor 19 with the bearing axle 22 and the bearings 23 and 24, as well as 
the pump wheel 25, and also the pump chamber 26 or at least its greater 
part as well as the filter chamber 31, the pressure passage 40, and the 
suction passage 30. At least a substantial part of the suction passage 30 
is a component of the second segment 60. 
The third segment 70 is formed as a substantially cap-shaped cover. It can 
be placed on the second segment 60 from above so as to close the second 
segment. The third segment 70 has at least one outlet opening 32 which is 
connectable with a filter chamber 31, and also at least one outlet opening 
41 which is connectable with the pressure passage 40. 
The so assembled inner filter 10 in the assembled condition of the three 
segments 50, 60 and 70 is a longitudinally extending substantially 
four-cornered body, especially rectangular or square body as shown in FIG. 
2. During the use this body is oriented substantially vertically and held 
in the aquarium tank 11. The third segment 70 especially in form of the 
substantially cap-shaped cover, is placed on the upper side of the second 
segment 60 and not against the first segment 50 Therefore in the placed 
position the second segment 60 extends at the upper side up to the height 
of the substantially vertical, longer L-leg 52 of the first segment 50. In 
accordance with a not shown example, the inner filter can be formed as a 
longitudinally extending and substantially round and/or cornered for 
example triangular body. 
The third segment 70 has for example a round cap 71 which closes the 
pressure passage 40 substantially in the region of its upper end 42 and 
has at least one opening 72. As can be seen from FIG. 4 the opening 72 is 
formed as a substantially reverse U-shaped slot and forms the above 
described outlet opening through which the water exits from the pressure 
passage 40 and is supplied back into the aquarium tank 11. The cap 71 has 
for example a substantially cylindrical wall 73 and is inserted with this 
wall into the third segment 70. It is turnably adjustable in it, for 
example, over a turning angle of maximum 70.degree.. Thereby the cap 71 
forms an upper turning discharge, so that the user by rotating the cap 17 
can provide the discharge direction. 
Moreover, the third segment 70 is provided with a device for controlling 
the volume flow. For this purpose the third segment 70 has for example a 
slider which controls the throughflow cross-section in the pressure 
passage 40, in particular the transition region of the pressure passage 40 
to the outlet opening 41. The slider 74 controls the volume stream. It 
engages transversely in a tubular part 75 of the third segment 70 and 
controls its throughflow cross-section. 
An adjusting handle 76 which operates in the same slider direction and can 
be grasped from outside engages the slider 74. It is held in the third 
segment 70 so that it is transversely displaceable. The third segment 70 
is formed as a one-piece synthetic plastic member, in which the cap 71 and 
the transversely displaceable slider 74 with the adjusting handle 76 can 
be exchangeably inserted. The third segment 70 is connectable with the 
upper end of the second segment 60 for example by a plug connection. The 
tubular part 76 extends in the upper end 42 of the pressure passage 40 to 
produce at least a substantially tight connection. 
The third segment 70 can have at least one projection. In the shown 
embodiment of FIG. 1 it has two projections 77 and 78 each provided with 
openings 79 and 80 which form the suction openings 72. The openings 79 and 
80 can be formed for example as substantially vertically extending slots. 
Each projection 77, 78 passes from the opening 79, 80 in the suction 
passage 30, especially first in the filter chamber 31. Both projections 
77, 78 are located on the front side 81 which is oriented to the left in 
FIGS. 1 and 2 and project from it. The projections 77, 78 extend at a 
distance from one another and substantially parallel to one another and 
formed identically. Each projection 77, 78 engages the second segment 60 
on its associated upper end around the corresponding front side 61. 
The opening 72 which first the outlet opening 41 in the cap 71, especially 
in its wall 73, of the third segment 70 is provided on the same front wall 
81 on which the opening 79 and 80 which form the suction opening 32 are 
provided by means of the both-side projections 77, 78. However, the 
opening 72 is located above, so that there is a clear vertical separation 
between the outlet opening 41 and the suction openings 32 on the other 
hand. 
Details of the first segment 50 are explained hereinbelow. This segment is 
formed preferably as a one-piece synthetic plastic member in which the 
stator 18 with the electrical conductor 20 is inserted. The reverse side 
12 of the longer, substantially vertical leg 52 forms the mounting side. 
The holder 15, for example the suction member is provided on this side for 
releasable mounting on the inner side 13 of the aquarium wall 14. A 
substantially trough-shaped receptacle 53 is provided in the rear side 12, 
and the electrical conductor 20 is upwardly guided in the receptacle 53 
The stator 18 of the electric motor 17 is located in the lower part of the 
first segment 50, especially in the substantially horizontal, shorter leg 
51 and/or transition region between the legs 51, 52 wherein a 
corresponding space is available. The stator 18 is mounted in the first 
segment 50 with a water tight closure. The passage 21 which receives the 
rotor 19 is substantially vertically oriented in the stator 18. 
The first segment 50 has a substantially vertically extending front wall 54 
which extends at a distance from the rear side 12 and forms a rear wall 
limitation of the suction passage 30. By withdrawing of the second segment 
60 from the first segment 50 which remains on the aquarium wall 14 the 
suction passage 30 is released. In the lower region 54 which guides the 
substantially horizontal short leg of the first segment 50, the front wall 
54 forms a part of the wall limiting of the pump chamber 26 in which the 
inclined wall 56 is extended. 
The second segment 60 is formed also as one-piece synthetic plastic member. 
The rotor 19 together with the bearing axle 22 and the bearings 23, 24, as 
well as the pump wheel 25 and in some cases at least one filter insert 34 
are exchangeably inserted in the synthetic plastic member. 
The second segment 60 is shorter by the height of the third segment 70 and 
by the height of the substantially horizontal short leg 51 of the first 
segment 50, and also is smaller by the depth of the substantially vertical 
leg 52 then the first segment 50. The dimension of the second segment 60 
is selected so that the second segment is placed on the forwardly 
projecting part of the substantially horizontal shorter leg 51 of the 
first segment 50, and together with the first segment 50 forms a body 
having a substantially four-cornered cross-section, in particular a 
substantially rectangular or square cross-section as shown in FIG. 2. 
The second segment 60 has a substantially L-shaped inner passage which is 
closed by the walls 62 an 63 leading to the pump chamber 26. The inner 
passage forms the pressure passage 40 and extends over the substantially 
vertical, longer leg at the front side and also at the substantially 
horizontal shorter leg to the rear side so as to form the pump chamber 26, 
and extends under the bottom region. Therefore the filter chamber 31 in 
the interior of the second segment 60 adjoins the inner wall 63 and is 
limited by the inner side of the wall 63, the remaining region of the 
adjoining front wall 64, and two substantially parallel side walls 63 The 
second segment has an upwardly extending wall part 66 which is provided on 
its rear side and faces the front wall 54 of the first segment 50. The 
wall part 66 extends substantially over the half height of the second 
segment 60 and limits the filter chamber 31. The wall part 66 limits 
moreover with its rear side a corresponding portion of the suction passage 
30. The suction passage in the operative condition of the inner filter 10 
is limited by the front wall 54 of the first segment 50. 
The second segment 60 further has a bottom part 67 which is connected as 
one-piece with the wall 63 and the rear side wall part 66 and extends in a 
transverse direction from one side wall 65 to another side wall 65. The 
upwardly facing side of the bottom part 67 forms the bottom of the filter 
chamber 31, while the downwardly facing side forms an upper limit of the 
pump chamber 62. The vertically extending wall part 66 merges arcuately or 
as shown here inclinedly into the bottom part 67 The inclined course of it 
substantially corresponds to the inclined course of the inclined wall 56 
of the first segment 50 which extends at the rear side at a distance from 
it. In the extension of the inclined wall 56, extends short inclined wall 
piece 68, which goes from one side wall 65 to another side wall 65 and is 
also a one-piece part of the segment 60. The wall piece 68 extends the 
inclined course of the inclined wall 68 and completes the inclinedly 
outwardly oriented transition conduit portion which connects the suction 
passage 30 with the pump chamber 26. 
The filter insert 34 inserted in the filter chamber 31 is held in the 
region of the bottom part 67 with its lower end at a distance above the 
bottom part 67. This has the advantage that the filtered out dirt 
particles or the like can accumulate in this lower region. The wall part 
66 which is oriented upwardly at least substantially over the half height 
of the second segment 60 has the advantage that, together with the side 
walls 65 and the inner walls 63 as well as the regions of the front wall 
64 extending at both sides, it forms a trough of a corresponding height. 
During withdrawal of the filter insert 34 upwardly water remains in the 
trough, it is contained in the second segment 60 and also in the filter 
insert 34 and can be loaded with the dirt particles. It is therefore 
guaranteed that during the exchange of the filter insert 30 the water 
which is located in the above described trough and in some cases is 
contaminated is caught there and does not flow into the aquarium tank 11. 
Vertically extending projections 69 serve for vertical spacing of the 
filter insert 34. They can be formed for example as webs on which the 
filter insert 34 is held in the filter chamber 31. 
The bottom part 67 of the second segment 60 has a reversely U-shaped part 
19 which is oriented upwardly toward the filter chamber 31. The upper 
bearing 33 formed for example as a rubber lip for the upper end of the 
bearing axle 22 of the rotor 19 is received in the portion 90. The portion 
90 with its wall facing the filter chamber 31 forms a projection which 
corresponds to the projection 69. It can serve as a spacer at the lower 
side of the filter insert 34 which sits on it. 
The pressure passage 40 is formed as an inner passage in the second segment 
60, separated from the filter chamber 31. The inner passage is limited 
from outside on the one hand by the front wall 82 which is designed as a 
forwardly projecting somewhat gallery-like wall strip. It extends 
substantially in the central region of the front side 61 of the second 
segment 60 from above downwardly and between both front walls 64. 
Inwardly, the inner passage is limited by the inner wall 63 The inner wall 
63 is curved inwardly to the filter chamber 61 and extends substantially 
over the width of the outer wall 62. It projects with its side edges from 
inside to the wall 62 so as to form a closed passage. Both walls 62 and 63 
limit an inner tubular passage which is closed relative to the filter 
chamber 31 up to the pump chamber 26. 
The second segment 60 moreover has a downwardly projecting holding device 
91 in the region under the pump chamber 26. The rotor 19 together with the 
bearing axle 22 and the bearings 23 and 24 is held on the holding device 
91. During placing of the second segment 60 on the substantially 
horizontal shorter leg 51 of the first segment 50, the holding device 91 
extends in the interior 57 of the leg 51 of the first segment 50, so that 
the rotor 19 is received in it and therefore extends in the passage 21 of 
the stator 18. The holding device 91 has a downwardly projecting 
supporting part 92 and a lower bearing cap 93. The lower bearing 24, for 
example a rubber lip for the lower end of the bearing axle 22 of the rotor 
19 is received in the bearing cap 93. The rotor 19 with the bearing axle 
22 and both bearings 23 and 24 is held in this manner in the segment 60, 
while the pump wheel 25 is held in the upper end of the rotor 19 which 
extends into the pump chamber 26. 
When the inner filter 10 is assembled for operation as shown in FIGS. 2 and 
3, and inserted in the above described manner in the aquarium tank 11 and 
mounted on the aquarium wall 14 the inner filter 10 is turned on and the 
pump wheel 25 is driven by the rotor 19 in a rotary direction. Thereby the 
water is aspirated from the interior of the aquarium tank 11 through the 
suction openings 32 in form of the openings 79, 80 and in particular the 
slots on the projections 77, 78 into the filter chambers 31, and through 
the filter insert 34 located in the filter chamber transversely to it. The 
water flows through the suction passage 30 and the pump chamber 26 in the 
closed inner pressure passage 40 and through it is raised, discharged at 
the upper end of the inner filter 10 through the outlet opening 41 
especially the slot shaped opening 72 in the cap 71 in correspondence with 
the arrow in FIG. 2, and then is again supplied into the aquarium tank 11. 
Due to this circulation of the water, it is cleaned in the inner filter 10 
by filtration. When needed, an electric heating device for heating can be 
integrated. 
The electric part of the electric motor 17 and the electric conductor 20 
are sealed so that a contact with water is reliably prevented. 
From time to time individual components of the inner filter must be 
cleaned. This can be practiced by a user fast, simple without special 
knowledge and special tools in the following manner. With the switched-off 
electric motor 7, the user first pulls the third segment 70 formed as the 
upper cover for example upwardly from the second segment 30, so as to 
release the upper end of the second segment 60. 
The thusly separated third segment 70 can be cleaned by the user without 
difficulties. If desired, also the cap 71 and/or the slider 74 with the 
adjusting handle 76 can be released when cleaning is desired in these 
regions as well. Also, it is performed for the purpose of exchanges in the 
event of damages and the like. 
When only the filter insert 34 is to be exchanged and for example cleaned, 
the user reaches from above in the filter chamber 31 and pulls out the 
filter insert 34. Some dripping water as well as water still located in 
the filter chamber 31 which can be loaded with dirt particles is collected 
in the above described manner inside the trough in the filter chamber 31 
and hinders flowing out or draining in the aquarium tank 11. The removed 
filter insert 34 can be cleaned or exchanged with another insert. After 
this in a reverse manner the third segment 70 is placed again, so that the 
inner filter 10 is again operational. 
When it is necessary to clean the interior of the second segment 60, for 
example also the pump wheel 25 and the region adjoining it, the second 
segment 60 is released from the first segment 50 which remains in the 
aquarium tank 11 and removed from the aquarium tank. Also, some water 
loaded with dirt particles located inside the filter chamber does not 
drain in the aquarium tank 11 and contaminates it. During withdrawal of 
the second segment 60 simultaneously the rotor 19 with the bearing axle 22 
and the bearings 23 and 24 is separated from the first segment 50 and 
pulled out upwardly so that all components of the rotor including the pump 
wheel 25 become freely accessible. Also, the interior of the pump chamber 
26 is then available from outside since the lower region 55 which limits 
the pump chamber 26 at the right end in FIG. 3 is a component of the first 
segment 50 an remains in the aquarium tank 11 during the separation. Also 
the wall part 66 of the suction passage 30 is freely accessible, since the 
other front wall 54 which limits the suction passage remains as a part of 
the first segment 50 in the aquarium tank 11. 
With the removed second segment 60 the whole rotor 19 with the bearing axle 
22 and the bearings 23 and 24 and with the pump wheel 25 can be cleaned, 
maintained and if necessary replaced. Also, the interior of the filter 
chamber 31 can be cleaned without problems with the removed filter insert 
34. When the inner filter 10 is again assembled to form an operational 
body, it is performed in a reverse manner and can be done fast and without 
difficulties. 
In accordance with another, not shown, embodiment the suction openings 32 
are provided not in the segment 70, but instead they are formed on the 
suction regions of the front side of the front wall of the first segment 
60, for example by webs and channels between them. They can be engaged 
from above by the second segment 60, whereby a connection with the filter 
chamber 31 and the suction passage 30 is provided. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described as embodied in an 
inner filter, it is not intended to be limited to the details shown, since 
various modifications and structural changes may be made without departing 
in any way from the spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention.