GB2248558A

GB2248558A - Aquarium filter

Info

Publication number: GB2248558A
Application number: GB9028088A
Authority: GB
Inventors: Kazutoshi Tominaga
Original assignee: Tominaga Jyushi Kogyosho KK
Current assignee: Tominaga Jyushi Kogyosho KK
Priority date: 1990-10-08
Filing date: 1990-12-27
Publication date: 1992-04-15
Also published as: JPH0461609U; GB9028088D0

Abstract

An external filter for an aquarium comprises a frame 1 which mounts on top of the tank and carries a pump unit 4 and a stack of two or more separate filter units 10, 11, 12 through which water from the pump filters downwards in series to outlet 17. Each filter unit consists of an open rectangular vessel fitting on to the unit or frame beneath. As shown the upper units contain cotton or glass wool, and the lowest unit 10 contains elements covered with active carbon on which bacteria breed for biochemical purification. The upper units remove solid impurities and are cleaned more frequently than the lower. Overflows 13, 18 are provided at each level. Lid 24 has a feeding hole 24a. <IMAGE>

Description

FILTERING DEVICE FOR A HOUSEHOLD AQUARIUM The present invention relates to a filtering device for use in association with a household aquarium in which fishes and aquatic plants are reared for pleasure.

Formerly this type of filtering device used for household aquariums, such as described in the specification of UK Patent GB 2131710 B, has been in general use. This device comprises an oblong framework being transversely placed on the side top walls of an aquarium. The central portion of the framework is a filtering unit loaded with a filtering element. The aquarium water is successively circulated through the filtering unit for purification.

The filtering device described above is capable of cleaning aquarium water by both physical purification that filters waste material from the water, and biochemical purification by which self-multiplying microorganism within the filtering element resolves waste material contained in the water.

In the beginning of use of this type of filtering device, only the physical purification described above is effective because the microorganisms necessary for biochemical puriication do not multiply quickly enough to be effective from the start.

The necessary microorganisms will multiply in course of time sufficiently enough for biochemical purification to work effectively. However, by this time a large quantity of waste material may have accumulated on the surface of the filtering element, causing the filtering devise to plug up, preventing full effectiveness of physical purification.

Therefore, the filtering element which has plugged up in this way must be cleaned. It is to be noted that when the mud which has accumulated on the surface of the filtering element is washed away, so too are the microorganism which have multiplied in the filtering element. Accordingly, the efficiency of both the physical and biochemical purifications cannot be expected at the same time.

In consideration of this problem, the present invention aims at providing a filtering device for use in association with a household aquarium which is capable of efficiently enhancing both physical and biochemical purification.

Other objects and advantages of the present invention will become apparent from the detailed description given below.

The filtering device in the present invention comprises at least two separable filtering tank units which are stacked one upon the other and laid as a whole on a supporting framework, with the upper filtering tank unit(s) providing a principal space for physical purification, while the lower filtering unit provides a principal space for biochemical purification.

In detail, this filtering device for use in association with a household aquarium comprises the supporting framework which is transversely placed on the side top walls of an aquarium, the filtering tank units being easily placed on or removed from the top of the aquarium. The filtering device mentioned above constitutes a filtering system and includes at least two separable filtering tank units placed one on top of the other, whose top sides are open so as to allow the dirty water pumped up from the aquarium to enter this system from the very top filtering tank unit and flow successively down through the lower filtering tank unit and back into the aquarium as cleaned water.

The dirty water from the aquarium which is carried up into the very top filtering tank unit and successively drained down through the lower filtering tank unit is purified by filtering elements loaded into each filtering tank unit. Even if the filtering element of the top filtering tank unit would become plugged up by the accumulation of waste material on its surface, biochemical purification will nevertheless be maintained in the lower filtering tank unit, because only the plugged up filtering tank unit(s) on top need be cleaned.

In the accompanying drawing: Fig. 1 is a vertical cross-section of a filtering device in an embodiment of the present invention; Fig. 2 is a perspective view showing the filtering device in its disassembled state; and Fig. 3 is a vertical cross-section of a filtering device in another embodiment of the present invention.

The present invention will be described below in more detail by way of example with reference to the accompanying drawings.

A filtering device in the embodiment shown in Fig. 1 comprises a supporting framework 1 mounted on tops (a) of opposite side walls of an aquarium (A), and a filtering tank system 2 consisting of a set of filtering tank units 2 placed on and separable from the supporting framework 1.

As shown in Fig. 2, the supporting framework 1 described above consists of a stationary portion 1a which is long sideways and a separate slidable portion 1b. The stationary portion la includes a pump unit site 4 on one end surrounded by side walls 3. The other end of the supporting framework is left open without a wall. The slidable portion 1b with three side walls 6, is inserted into the open end side of the stationary portion la, wherein a pair of upside down L-shaped slide guides 5 are provided on the inner side of the accepting side wall 3 are provided. The slide walls 6 of the slidable portion Ib are held in place in the stationary portion 1a by these slide guides 5. In this way, the slidable portion 1b is freely slidable and retractible in a longitudinal direction of the stationary portion la.

Thus, by inserting the slidable portion Ib into the stationary portion la, the two portions are united into the supporting framework 1 which can thus be Extended and retracted as a whole adjustable in length. The slidable portion 1b comprises a thermostat hole 7 in which a thermostat (S) is fixed and a heater cord hole 8 in which a cord leading to the heater (H) is inserted. A heater unit site 9 receives the thermostat (S) and the heater (H).

The filtering tank system 2 consists of at least two oblong filtering tank units 10, 11 and 12 made of transparent plastics. The top side of each tank unit is open.

As shown in Fig. 1, the bottom of the lowest filtering tank unit 10 is molded into a circumscribing stepped recess 10a adapted to securely fit onto the side walls 3 of the supporting framework 1. Both ends of the supporting framework 1, i.e., the pump unit site 4 and the heater unit site 9 protrude from both sides of the filtering tank system 2.

Within the lower filtering tank unit 10, a detachable vertical partition 13 is placed in order to create a returning water tank space 14 and a filter element space 15.

The filter element space 15 accommodates a grid plate 16 on the stepped recess 10a so that both spaces 14, 15 are joined in liquid communication by a sub-level gap formed between the grid plate 16 and a lower end of the detachable vertical partition 13. The bottom wall of the returning water tank space 14 is provided with an opening 14a. A removable outlet duct 17 is inserted in the opening 14a.

The upper filtering tank unit 11 consists of a molded transparent plastics body with a circumscribing stepped recess 11a underneath to allow the upper filtering tank unit 11 to be securely set on top of the lower filtering tank unit 10. In doing so, the constricted circumscribing stepped recess 11a securely fits inside of the top edge walls of the bottom filtering tank unit 10. Internally, the upper filtering tank unit 11 comprises a fixed integral partition wall 18 corresponding to the detachable vertical partition wall 13 of the bottom filtering tank unit 10.

The part corresponding to the filtering element space 15 of the bottom filtering tank unit 10, has small drain holes 19 along the bottom surface 20 of a filtering element space 21. The area corresponding to the returning water tank space 14 described above is bottomless in order to allow overflow water above the fixed vertical partition wall 18 to flow down directly into the returning water tank space 14.

The reference numeral (M) designates an electric pump motor, reference numeral 22 designates a bracket, 23 designates a pump duct, and 24 designates a transparent plastic lid with an round opening 24a for dropping fish food into the aquarium.

The filtering device in operation consists of the fully expanded supporting framework 1 which is transversely placed on top of the opposite side walls of the aquarium (A), and the filtering tank units 10 and 11 which are placed on the supporting framework 1.

Inside of each filtering tank unit 10 and 11, filtering elements (X) of such materials as cotton and glass-wool are accommodated. In this embodiment, the upper filtering tank unit 11 is stuffed with the filtering element (X) consisting of cotton and glass-wool, and the lower filtering tank unit is stuffed with many individual purifying elements (Y). The purifying elements (Y) each comprises a small columnar piece and branch-like lugs radially protruding from a middle portion of the piece, with their surfaces being covered with adsorbent active carbon.

By turning on the electric pump motor (M), aquarium water is pumped up through the pump duct 23 from òne side of the aquarium (A) to the upper filtering tank unit 11 and distributed into the filtering element (X). After the water drains through the filtering element (X), it is distributed evenly into the individual filtering elements (Y) in the bottom filtering tank unit 10 through small drain holes 19 on the bottom surface 20. In this filtering tank unit 11, biochemical purification works effectively because active carbon layer on the surface of the individual purifying element contains an infinite number of small holes in which aerobic bacteria are allowed to multiply undisturbed.

The water cleaned in such a manner returns to the aquarium (A) through the outlet duct 17. The thermostat (S) is inserted into the thermostat opening 7 of the heater unit site 9, and the heater (H) is placed inside, near the thermostat and on the bottom of the aquarium (A), its cord leading through the heater cord hole 8.

Fig. 3 shows an alternative embodiment of the filtering device. In addition to the double layered filtering system 2 mentioned above, another filtering tank unit 12 of the same structure as the unit 11 is securely set on the top thereof, creating a triple layered filtering system 2 consisting of three filtering tank units 10, 11 and 12. It is understood that the nomenclature for the parts in both filtering tank units 11, 12 are identical, therefore further explanation is omitted here. In this case, the uppermost filtering tank unit 12 and the intermediate tank unit 11 accommodate a cotton or glass-wool filtering element (X), and the bottom filtering tank unit 10 accommodates individual purifying elements (Y) coated with a layer including an active carbon.These individual purifying elements each comprises a small columnar piece and branch-like lugs protruding radiålly from a middle portion thereof. The two upper filtering tank units 11, 12 are mainly for physical purification, while the bottom filtering tank unit 10 is for biochemical purification.

In the above two cases, two or three filtering tank units are stacked one upon the other forming a double or triple layer filtering system2. However, four or more filtering tank units may be employed if necessary.

It may be also advisable to load the filtering element (X) of cotton and glass-wool into the upper filtering tank unit 12, and individual purifying elements (Y) as an excellent medium for multiplying micioorganism into the lower filtering tank units 10 and 11 in order that physical puri fication may be effected mainly in the top filtering tank unit 12 and biochemical purification mainly in the bottom filtering tank units 10 and 11. Further, it will be also effective to load the same filtering element (X) such as cotton and glass-wool into all the filtering tank units.

According to this method, when the filtering element placed in the top filtering tank unit gets plugged up with mud at a fairly early stage, physical purification is revived simply by cleaning the filtering element in the top of tank unit. The advantage of the method is that, biochemical purification is maintained in the lower level filtering tank unit(s) as microorganisms are allowed to multiply undisturbed. When the pH of the aquarium water need be adjusted, it is advisable to put into the filtering tank units some material, like coral sand, which serves this function of pH adjustment.

The present invention, a filtering devise for a household aquarium, as described above, consists of at least two separable top and bottom filtering tank units with open tops, in which the pumped aquarium water filters successively through the uppermost filtering tank unit down into the lowermost filtering tank unit to circulate back into the aquarium. In this way, the aquarium water can be filtered through several filtering elements several times, ensuring a more effective method of purification. Furthermore, since the filtered aquarium water comes into contact with air when passing through each filtering tank unit and thereby agitated, the cleaned water which circulates back into the aquarium is sufficiently oxygenated.

When the filtering elements which are loaded into the upper filtering tank units becomes plugged up by mud accumulating on its surface, only that filtering elements need be washed. This leaves the self-multiplying microorganisms necessary for biochemical purification, undisturbed in the lower filtering tank units thereby insuring more effective water purification treatment by both physical and biochemical purification.

The filtering device consists of a number of separable filtering tank units as described above so that the whole filtering devise is made compact for easy transport and storage, and for easy cleaning of the various filtering elements.

Claims

1. A filtering device for use in association with a household aquarium, the filtering device comprising a supporting framework placed on top of the aquarium, a filtering tank system separably placed on the supporting framework, the filtering tank system comprising at least two top and bottom filtering tank unit stacked up one on another, wherein water is pumped up from the aquarium and allowed to flow from the uppermost filtering tank unit successively into the lower filtering tank units and circulating back into the aquarium.

2. A filtering device as defined in claim 1, wherein the filtering system consists of the three filtering tank units stacked up one on another.

3. A filtering device as defined in claim 1 or 2, where in the lowest filtering tank unit has a circumscribing stepped recess on its bottom end portion, which recess securely fits into the side walls of the supporting framework.

4. A filtering device as defined in claim 1, 2 or 3, wherein the lowest filtering tank unit comprises therein a detachable vertical partition o create a returning water tank space and a filtering element space, the filtering element space accommodating a grid plate on the circumscribing constricted stepped recess, and wherein the returning water tank space is in liquid communication with the filtering element space, through a sub-level gap formed under the detachable vertical partition.

5. A filtering device as defined in claim 4, wherein the bottom wall of the returning water tank space is provided with an opening and a removable outlet duct inserted in the opening.

6. A filtering device as defined in claim 1 or 2, wherein the filtering tank units, except for the lowest one, accommodate an attached vertical partition which creates a returning water tank space and a filtering element space which are disposed in longitudinal direction of the tank unit, the filtering element space comprising the bottom wall having many small holes so as to allow the free drainage of aquarium water into the next fil tering tank unit, and wherein the bottom of the return ing water tank space is open to allow excessive water which flows over the partition to directly flow down into the returning water space of the lowest filtering tank unit.

7. A filtering device as defined in claim 1, 2 or 6, wherein the filtering tank units, except for the lowest one, are made of a molded transparent hard plastics.

8. A filtering device as defined in claim 1, 2, 6 or 7, wherein the filtering tank units, except for the lowest one, comprise a circumscribing constricted stepped recess on the bottom, the stepped recess securely fitting into the top side walls of the filtering tank unit disposed directly below.

9. A filtering device as defined in claim 1 or 2, wherein the top filtering tank unit is provided with a removable lid placed on top thereof and comprising an opening through which fish food is dropped into the aquarium.

10. A filtering device as defined in claim 1, wherein the supporting framework is composed of a stationary portion and a slidable portion combined therewith so as to make the framework as a whole substantially ex tensible and retractable in longitudinal direction.

11. A filtering device constructed and arranged to operate substantially as herein described with reference to and as illustrated in any of the Figs. of the accompanying drawings.