Internal corner filter, particularly for small tanks and aquariums

An internal corner filter, particularly for tanks and aquariums, includes a container (2) that can be anchored to the upper rim of a tank (V) at an internal corner thereof. The container has a filtration part (9) and has an intake port (7) and a discharge port (8) which are connected to the tank (V). Circulation of the water to be filtered through the container (2) occurs by virtue of a pump which is coupled to as to avoid seepage and/or accidental leaks of water towards the outside of the aquarium.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an internal corner filter for small tanks 
and aquariums, of the type which can be placed in a corner of the tank. 
2. Description of the Prior Art 
Known corner filters are generally formed by a container that can be 
anchored to the bottom of the aquarium. A filtering material is arranged 
inside the container which has a closure lid, an inlet, and an outlet 
which are connected to an air pump for circulating the water to be 
filtered through the filter. The pump is located outside the aquarium and 
is connected to the filter by a small tube. The pump also has the purpose 
of aerating the pumped liquid and thus allows oxygenation of the life 
forms that live in the aquarium. The filtering material is generally 
constituted by natural or synthetic porous stones which retain impurities 
and allow the liquid to pass. 
Although these known devices are in widespread use, they have some 
acknowledged structural and functional drawbacks, including first of all 
the presence of tubes, various connectors and a one-way valve to connect 
the container to the external pump and to prevent backflow of water if its 
delivery jams or clogs up. This leads to a certain complexity in 
construction and assembly which also increases the difficulty of 
operations for the maintenance of the device and worsen its overall 
aesthetic appearance, which does not harmonize with the ornamental 
function of the aquarium. 
Another drawback is the high noise of the pump. 
Another drawback of these filters is their excessive overall cost, which is 
also increased by the considerable cost of the external valves and 
connectors. 
Another drawback is the limited life of the filtering material, which 
easily clogs and cannot be cleaned easily; this entails the replacement of 
the entire container, increasing the maintenance costs of the device. 
The aim of the invention is to eliminate the drawbacks described above by 
providing an internal corner filter which is structurally simple and 
compact so as to be advantageous from an economical point of view. 
An object is to provide an internal filter that has absolutely no external 
components, so as to simplify assembly and maintenance operations to the 
maximum possible extent. 
Another object is to provide an internal filter that is quiet and is 
aesthetically very pleasant. 
SUMMARY OF THE INVENTION 
This aim, these objects and others which will become apparent hereinafter 
are achieved by a compact corner filter, particularly for small tanks and 
aquariums, comprising a container that can be anchored to the upper rim of 
a tank at an internal corner thereof, a filtration part, being arranged in 
said container, said container having an intake port and a discharge port 
which are connected to the inside of the tank and are connected to a 
pumping means for circulating the water to be filtered, said filtration 
part dividing the container into a first chamber and a second chamber 
which can be respectively connected to the outside by said intake port and 
said discharge port, said pumping means being constituted by a submersible 
micro-pump which is arranged inside said first chamber and has a suction 
inlet that is connected to said intake port. 
By virtue of this arrangement, the filter is entirely included in the 
container, and has no connection to an external pumping means, thus being 
extremely simple and compact and easy to assemble and maintain.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
With reference to the above figures, the internal corner filter, according 
to the invention, generally designated by the reference numeral 1, 
includes a container 2 that can be anchored to the internal upper rims in 
a corner of a tank or aquarium V. 
The container 2 is generally prism-shaped, with a substantially triangular 
transverse cross-section formed by a base wall 3 and by three side walls 
4, 5, and 6. The first two side walls 4 and 5 are substantially identical 
and flat and form a right angle between them. The third wall 6 is inclined 
with respect to the first two and is slightly curved outwards. 
The container 2 is open at the top and has two ports 7 and 8: respectively 
a port 7, formed on the base wall 3, for the intake of the water to be 
filtered, and a port 8, formed on the curved side wall 6, for the 
discharge of the filtered water. 
A filtration part 9 is arranged inside the container and is constituted by 
a substantially flat panel of fibrous material which is arranged 
vertically along the line that connects the acute angles of the triangular 
cross-section of the container, so as to divide the internal chamber of 
the container into a first partial chamber 2', connected to the tank V by 
the intake port 7, and a second partial chamber 2", connected to the tank 
by the discharge port 8. 
The base wall 3 of the container 2 is correspondingly divided by the 
filtration part into a portion 3' and a portion 3" which belong to the 
respective chambers 2' and 2". 
Conveniently, in order to stabilize the filtration part 9 in the desired 
position, two guides or longitudinal supports 10 and 11 are formed in the 
corners that lie between the side walls 4 and 5 and the curved side wall 
6; said guides retain the vertical edges of the filtration panel. 
The height of the filtration part 9 must be less than the maximum height of 
the container 2 and more than the overflow level of the discharge port 8, 
so as to avoid the overflow of the water contained by the edges of the 
container 2 if the filtration part 9 becomes clogged. 
According to the invention, a submersible micro-pump 12 is detachably 
anchored in the intake chamber 2' of the container 2 and has a pump body 
13 having a substantially cylindrical axial symmetry of the type disclosed 
in the European Patent Application No. 94109686.9. 
A discharge outlet 14 is formed at the lower end of the pump body 13 and 
has a variable cross-section to adjust the flow-rate, whereas the cable 15 
for the supply of electric power to the driving motor protrudes from the 
upper end. 
Conveniently, the pump is connected to the intake port 7 by a choke 
pre-chamber which is formed by a cylindrical part 16 that is anchored to 
the bottom 3' of the chamber 2' by a circumferential edge 17 that abuts 
against a collar 18 formed on the base wall 3. A tooth 19 is formed on the 
collar 18 and engages a corresponding seat of the cylindrical part 16 to 
prevent its rotation about its own axis. 
The adjustable discharge outlet 14 is constituted by a first series of 
radial openings 14' which are formed circumferentially on the side wall of 
the body 13, peripherally with respect to the impeller, and can be aligned 
with a second series of corresponding openings 14" that have the same 
spacing and are formed on the cylindrical part 16. The cylindrical body 13 
is retained axially with respect to the cylindrical part 16, but can 
rotate with respect to said part 16 so as to vary the extent to which the 
radial openings 14' are closed, correspondingly varying the flow-rate. 
Conveniently, the vertical position of the discharge port 8 is chosen so 
that it is lower than the upper portion of the pump body 13 which includes 
the electric parts, i.e. the connecting cable 15 and the switch 19, so 
that these parts always rise above the water. Accordingly, even if the 
pump is of the type that is encapsulated in epoxy resin, this arrangement 
is a safety enhancement to avoid leakage of current due to lack of 
insulation. 
The container 2 can be anchored to the upper rim of the tank by a simple 
engagement means which consists of brackets 21, 22, shaped like an 
inverted U and formed monolithically along the upper edges of the side 
walls 4 and 5. 
Accordingly, since the upper edges of the container are flush with the 
tank, no lid is necessary to protect the filter, because the lid of the 
aquarium itself is sufficient. 
The operation of the filter is evident from what has been described above. 
Water is drawn in through the port 7 formed on the base wall 3' and is 
poured into the first chamber 2', upstream of the filtration part, and 
then passes through the filtration part 9 and exits through the discharge 
port 8, returning to the aquarium. 
If the filtration part 9 is blocked, the water can overflow along its upper 
edge and returns to the tank, preventing the water from spilling outside 
the aquarium. 
The interchangeable filtration part may be of the type with integrated 
porous elements and fibers, of a type that is easily commercially 
available, with different porosity values according to the requirements of 
the user. The intake piece 7 can be removed to place the tube beneath the 
gravel of the aquarium if required. 
The container of the device is preferably made of transparent plastic by 
injection-molding or thermoforming. 
The internal corner filter according to the invention achieves the intended 
aim and objects and particularly has an extremely compact and simplified 
structure with respect to similar devices of the prior art. Furthermore, 
the filter has no tubes, connectors and one-way valves and accordingly 
does not require particular connections, simplifying all the assembly and 
maintenance operations to the maximum possible extent. The external 
appearance of the filter is extremely neat and does not alter the 
ornamental purpose of the aquarium. 
Although the invention has been described with reference to the embodiment 
illustrated in the drawings, it is understood that the filter is 
susceptible of numerous modifications and variations, all of which are 
within the scope of the inventive concept expressed by the accompanying 
claims.