GB2272944A

GB2272944A - Aquarium power head attachment means

Info

Publication number: GB2272944A
Application number: GB9325964A
Authority: GB
Inventors: Allan H Willinger; Robert Ellis
Original assignee: Willinger Brothers Inc
Current assignee: Willinger Brothers Inc
Priority date: 1990-05-29
Filing date: 1993-12-17
Publication date: 1994-06-01
Anticipated expiration: 2011-05-28
Also published as: GB9325964D0; GB9325963D0; GB2272943B; GB2272944B; GB2272943A

Abstract

A clamp 150 for attaching a power head (62 Fig. 25) to a wall of the aquarium tank (54) includes a suction cup 178 for attachment to the wall, a ring 168 which mates a tubular inlet portion 90 of the housing of the power head and an internally threaded tube 174 extending diametrically across the ring. Athreaded shaft 176 is disposed within the threaded tube 174 and has an end portion extending from the tube to contact the suction cup 178 and a rotatable knob 180 is fixed to the shaft for rotating the shaft, thereby to adjust the distance between the ring and the wall of the tank. <IMAGE>

Description

2272944 AQUARIUM POWER READ This invention relates to aquarium filtering

and aerating systems and, more particularly, to a clamp for attaching an aquarium power head to a wall of an aquarium tank.

Aquariums are used widely for housing f ish and other aquatic life. In order to provide'a proper habitat for the aquatic life. water held within an aquarium tank is generally filtered and aerated to ensure a removal of waste matter and provide an adequate concentration of oxygen. Aeration. and filtration of waste matter can be combined using the well-known undergravel filter system in which aquarium water is drawn through aquarium gravel spaced off the bottom by a porous plastic plate at the bottom of the tank. The filtered water flows upward through a riser tube and returns to the aquarium. A water pump. generally referred to as a power head. sits on the riser tube and lifts the water up the riser tube and then emits it back to the aquarium. An air passage in the power head causes air to be sucked in as the water passes and the air becomes entrained in the water so that the filtered water returning to the aquarium is now aerated.

Power heads suitable for use with an undergravel filter may be constructed to include a pump having an impeller operated by an electric motor. Water drawn into the power head passes through a water conduit. There is also provided an air-breather conduit which is in flow communication with the water conduit via an air-induction port in a sidewall of the water conduit. By venturi action, the air is drawn from the breather conduit into the flowing water to form a series of bubbles entrained In the stream of water. The motor, the impeller, and both of the conduits are encased within a housing. The housing includes water inlet and outlet ports for the water conduit, and an air inlet port for the breather conduit.

Typically, a clamp or holder is used to retain the power head over the riser tube. The holder permits 5 adjustment to position the power head properly. According to the invention there is provided a clamp for attaching an aquarium power head to a wall of an aquarium tank, the power head including a water conduit and a pump for pumping water of the tank through the conduit, the power head having a housing enclosing the conduit and the pump, the housing being provided with Inlet and outlet ports for the conduit, the inlet port being formed as a tubular section, the clamp engaging with said tubular section for affixing said housing to said wall of the aquarium tank, said clamp comprising:

a ring which mates with said tubular section; attachment means for engagement with said wall; and positioning means extending into said ring and engaging with said attachment means, there being space between said ring and said positioning means for the flow of water through the ring and into the inlet port.

Preferably, the clamp is arranged for use with a power head using an undergravel filter In an aquarium tank, the power head including a pump and fluid conduits housed in a housing having a substantially circular cylindrical sidewall. The substantially circular cylindrical shape avoids entrapment of a fish between the housing and the tank wall, which may contact the housing. The clamp can conveniently secure the housing at a corner of the tank with the power head held by the tank wall and conveniently positioned over the riser tube.

In order to silence the sounds produced by the sucking in and entrainment of air in the water, the power head may provide -for the Anclusion of a muffler as a part of the air breather conduit, the muffler being located between an air inlet port and an induction port in the water conduit wherein the air is mixed into the water. The muffler can be constructed in a low-profile configuration to permit a locating of the muffler within an end wall of the housing. This permits easy access by risers, by means of a removable panel In the muffler, for cleaning interior portions of the muffler.

The muffler can be constructed in a number of embodiments by use of a duct having an array of baffles -5 enclosed within the duct to provide a circuitous path to the passage of the air. The baffles are oriented transversely of a central axis of the duct. The baffles are spaced apart from each other to define a tortuous corridor for the flow of air through the duct. In addition, the baffles can extend inwardly of the duct from different sidevalls of the duct for interdigitation of the baffles. The interdigitation can impart a serpentine form to the corridor. Thereby, as the air progresses through the duct, it undergoes continuous changes in direction which enable the inlet noise to be absorbed as it flows into the housing. Preferably, the baffles are constructed as ribs integrally formed with sidewalls of the duct, a configuration which is readily manufactured by molding plastic.

To provide for the low-profile configuration of the muffler,, the duct can be formed with an enclosed configuration in which one opposed pair of walls may be regarded as a floor and a roof, with sidewalls interconnecting the floor and the roof. Different embodiments of the invention provide for different patterns of the baffles to Provide air passages in the forms of circuitous paths having different configurations. By way of example, alternate ones of the baffles can extend from the floor and the roof partway towards the opposite wall to provide an undulation in air passage which progresses in up and down fashion along the central axis of the duct. Alternatively, alternate ones of the baffles can extend inwardly from opposite sidewalls to provide an undulation from the air passage which progresses in a side to side fashion. The duct may have a linear form with input and output ports at opposite ends of the duct. Alternatively, a center partition may be provided within the duct to form a U-shape configuration of the passageway within the duct in which case the input and the output ports of the duct can be located coaxially to each other and extending in opposite directions from the duct. An adjustable air constriction valve may be utilized at the input port of the duct located on an exterior side of the pump housing to permit manual adjustment of an air flow rate.

By way of yet another form of construction which is employed in a preferred embodiment of the muffler, the lowprofile configuration of the muffler can be obtained by constructing the circuitous sinuous corridor as a series of circular segments shaking back and forth in a concentric arrangement which interconnects inlet and outlet ports of the muffler. Successive circular segments are interconnected by U-shaped and connector segments. This provides a configuration of a passageway with numerous different radii of curvature to attenuate the noise produced by the entry of air in the housing.

In the construction of the air-inlet valve in the power head incorporating any one of the foregoing embodiments of the muffler. the air-inlet valve may be located physically at the input port of the muffler. and may be constructed of two cylindrical sections which are nested, one within the other. The outer cylindrical section includes a sidewall aperture which opens to the external environment for receiving air, and which communicates with an air conducting channel in the inner cylindrical element. By rotation of the outer cylindrical element about the inner cylindrical element, the air inlet opening of the outer cylindrical element is offset relative to the air conduction channel of the inner cylindrical element resulting in a constriction of the passage for intake of air.

The entire housing may be potted with epoxy or other potting compounds to permit the power head to be submerged.

For a better understanding of the Invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, wherein:

Fig. 1 shows, in plan view, a fragmentary portion of an aquarium using a power head with flat walls; Fig. 2 shows a power head including circular cylindrical housing; Fig. 3 shows a plan view of an aquarium, similar to the view of Fig. 1, but including the power head of Figure 2; Fig. 4 is a top plan view of the housing of Fig. 2, the view including a muffler located on a top surface of the housing; Fig. 5 is a front elevation view of the power head of Fig. 2, the view being directed along an axis of an exit port for the aerated water; Fig. 6 is a side elevation view of the power head of Fig. 2; Fig. 7 is a bottom view of the power head Fig. 2; Fig. 8 is a sectional view of the power head of Fig. 21 taken along an elevation plane through the water outlet port, the view showing interior components of a pump assembly including an electric motor and impeller driven by the motor; Fig. 9 is a transverse sectional view of the pump assembly taken along the line 9-9 of Fig. 8; Fig. 10 is an exploded perspective view of a muffler situated at the top wall of the housing of Fig. 2e the view of Fig. 10 showing an array of baf flee upstanding from a bottom surface of a duct carrying air in an air breather conduit; Fig. 11 is an exploded perspective view of the muf f ler, similar to the view of Fig. 10. but showing an array of baffles disposed along a top surface of the air carrying duct; Fig. 12 is a perspective view of a completed assembly of the muffler of Pigs. 10 and 11. the view of Fig. 12 including a valve disposed at an input port of the muffler for selectively restricting a flow of air through the muffler; Fig. 13 is a plan view of the muff ler of Fig. 12. a portion of the upper surface of the muffler being cutaway to disclose the baffles, there being arrows depicting a flow of air in an undulating course among the baffles; Fig. 14 is a sectional view of the muffler taken along the line 1414 of Fig.12. the view Qf Fig. 14 showing interior details in the construction of the valve. the view also showing a coaxial arrangement of input and output ports of the muffler Including the central disposition of a partition to route air between the ports and the muffler; Fig. 15 Is a sectional view of the muffler taken along the line 15-15 in Fig.12. the figure showing an undulating course of flow for air provided by Interdigitation of the baffles extending from top and bottom surfaces of the aircarrying duct; Fig. 16 is an exploded view of the muffler in accordance with a further embodiment having a linear form with input and output ports located at opposite ends of the muffler. the view showing baffles disposed on an upper surface of an air-carrying duct; Fig. 17 is a perspective view of the muffler of Fig. 161 the view showing a top surface of the muffler; Fig. 18 is an sectional view of the muffler taken along the line 18-18 in Fig.17 and looking towards the top surface of the duct, the view showing interdigitation of the baffles by extension of the baffles from alternate sidewalls of the duct;, Fig. 19 shows an exploded view of the muffler in accordance with a further embodiment of the invention, similar to that of Fig. 18. but wherein the duct includes a central partition. this construction providing a U-shape flow arrangement to the air-carrying duct; Fig. 20 is a perspective view of the muffler of Fig. 19; Fig. 21 is a sectional view taken along the line 21-21 of Fig. 20. and being directed towards an upper surface of a duct to disclose the arrangement of the baffles extending in alternating fashion from both the central partition and from an outer encircling sidewall; Fig. 22 is an exploded view of yet another embodiment of the muffler having a linear form with input and output ports located at opposite ends of the muffler,the view showing upper and lower portions of the muffler angled to disclose baffles extending from both upper and lower surfaces of an air-carrying duct; Fig. 23 is a perspective view of the muffler of Fig. 22, the view of Fig. 23 showing a top surface of the muffler; Fig. 24 is a sectional view of the muffler taken along the line 24-24 of Fig.23, the view in Fig. 24 being taken along an elevation plane to show a serpentine passage for flow of air among the baffles; Fig. 25 shows a side elevation view of the power head assembly, and includes a description of the mounting of the pump head to an interior wall surface of an aquarium tank. and connection of an inlet water port of the power head to a riser tube of an undergravel filter;

Fig. 26 is a sectional view shoving connection of a clamp of Fig. 25 to an inlet port of the power head, the view of Fig. 26 being taken along the line 26-26 of Fig. 25.

Fig. 27 is a sectional view, taken along the line 27-27 of Fig. 25, and showing details in the construction of the clamp, the clamp holding the power head at a selectable distance from the tank wall of Fig. 25; Fig. 28 is an exploded view of another embodiment of the muffler wherein the air-carrying duct has been made circular to provide a serpentine duct configuration composed of a series of circular segments of different radii; and Fig. 29 is a sectional view of the muffler taken along the line 29-29 of Fig. 28, the view of Fig. 29 showing a plan view of an upper portion of the muffler of Fig. 28.

In the various figures of the drawing like reference characters designate like parts.

Fig. 1 shows a fragmentary view of an aquarium 40 including a power head 42 for use in causing a flow of the water in an undergravel filter arrangement within the aquarium 40. In accordance with the practice of the prior art. the power head 42 is partially submerged in the water. and is provided with a housing 44 having flat sidewalls such as walls 46 and 48. The aquarium 40 includes a tank 50 constructed of walls n and &c for contalning the water In the tank 50. Caps 56 and 50 are typically present respectively between the housing wall 44 and the tank wall At. and between the housing well 4 and the tank wall g4. riah 40# while swimming in the waters way become entrapped In on of the gapsy such as the gap 568 by being wedged between the walls 46 and 52. This presents a hazard to the, tish.

". 2-9 chow a power head 62 constructed within a totming 64 which Is formed with a sidewall 66 having a circular cylindrical surface. The housing s4 is closed off by rid wall#,, namely,,- &.top wall c and a bottom wall 10. As M In Fig. 3@ the power head 42 to slightly paced from the tank wall 54. tn this cause however. because of the cylindrical configuration of the housing, there Is no parallel wall between the power head and the tank wall. but only a tangential contact. As a result. the curvature of the sidevall 44 InhIbits a wedging and entrapment of the fish to between the sidewall of and the tank wall M.

The power head 42 Includes a puzp n (Itiga. a and 9) prlolng an olectclu ovtr 74 and an Impollor tc which is rotated by the Motor 74, The motor 74 is constructed In well-known fashion and Includes a rotor 70 and a atator a. The stator 00 Includes a winding 02 disposed on laminae 94 of magnetic material, such as iron. -Upon excitation of the winding 82 with electric current, the stator so produces a alternating magnetic field which imparts rotation to the rotor 78 and to the impeller 76 mechanically coupled to the rotor 78. Electric current for the inotor 74 is provided by a pair of electric wires 86 entering into the housing 64 via the top wall 68.

The power head 62 includes a water conduit 88 extending from a water inlet port 90 from the housing 64 to a water outlet port 92 of the housing 64. The inlet port go is located on the bottom wall 70 and opens in the downward direction for drawing in water from the tank SO. The outlet port 92 is located at the bottom of the sidewall 66, and opens in thehorizontal direction for directing an outgoing stream of water to return back to the aquarium tank SO. The impeller 76 may be disposed coaxially with the inlet port 90. The impeller 76 includes a set of radially extending vanes 94 located within the water conduit 68. Upon rotation of the impeller 76, the vanes 94 urge the water to flow through the conduit 88.

Also included within the pump housing 64 is an airbreather conduit 96 which extends from an air inlet port 98 at the top of the housing 54 to an air induction port 100 located on a sidewall of the water conduit 66. In response to the f lowing stream of water in the conduit a$, the X -isinduction port 100 acts as a venturi for drawing air from the breather conduit so Into the water of the conduit at. The air drawn into the water appears as a stream of bubbles entrained in the stream of water exiting the conduit 88 at the outlet port $a. The process of drawing air to the water. causes air to be sucked into the air inlet port so which produced a noise as the air enters. The sound is objectionable and a source of distraction to persons observing aquatic life in a home aquarium 40.

A muffler 102 is provided within the breather conduit 96 between the inlet port go and the induction port 100 for silencing the sound produced by the sucking in of air into the power head. Preferably,, the muf f ler 102 is located at the top wall to of the housing 64 to facilitate access to the muf f ler 102 for cleaning the muf f ler 102. The muf f ler 102 Is constructed with a bottom wall 104 or f loor. and a top wall 106, or roof, disposed parallel to the bottom wall 104. The bottom wall 104 is fixed to the top wall 68 of the housing 64. The top wall 104 Is removable for cleaning the muffler 102. A circuitous passage. in the form of a serpentine corridor. for the conduction of air is formed in the muffler 102 between the bottom wall 104 and the top wall 106. The serpentine corridor is connected serially with a lower tubular portion 108 and an upper tubular portion 110 a of the air-breather conduit $C to provide a continuous passage for the flow of air from the Inlet port go to the induction port 100. A valve 112 is constructed at the inlet port 98 to permit manual adjustment of the rate of flow of air in the breather conduit 96. As a convenience in manufacture. the air-inlet port 98 and the valve 112 may be constructed as an integral assembly with the top wall lot of the muffler 102.

Figs. 10-15 show details in the construction of the muffler 102 and the valve 112 in accordance with a first embodiment of the muffler 102. The muffler 102 comprises a lower set of baffles 114 extending upwardly from the bottom wall 104. and an upper set of baffles 116 extending downwardly from the top wall 106 into the spaces between the lower baffles 114 to provide an-intercalation of the baffles 114 and 116. The baffles 116 are spaced apart from the baffles 114 to provide space for the passage of air. Thereby, the interdigitated sets of baffles 114 and lit form the serpentine corridor for conduction of the air through the muffler 102.

The muffler 102 further comprises an input port lie located on the top wall 106 and an output port 120 located on the bottom wall 104. Two opposed sidewalls 122 and 124 and two end walls 126 and 128 plus a central partition 130 extending in a longitudinal direction of the muffler 102 interconnect the top wall 106 with the bottom wall 104. The input port 118 and the output port 120 are fabricated each in the form of a circular cylindrical tubular segment. The input port 118 and the output port 120 are arranged coaxially to each other. and extend In opposite directions away from the muffler 102. The partition 130 extends through the common axis of the ports 118 and 120 to segregate air flow at the input port 118 to the portion of the muffler 102 between the partition 130 and the sidewall 122, and to segregate the air flow at the output port 120 to the portion of the muffler 102 between the partition 130 and the sidewall 124.

Furthermore. an opening 132 of the port 118 in the top wall 106 (Fig. 14 and partially shown in Fig. 11) and an opening 134 of the output port 120 in the bottom wall 104 (shown in Figs. 10 and 14) are smaller than the areas of the cylindrical segments of the ports 118 and 120, and are offset to opposite sides of the common axis of the ports lit and 120. This arrangement of the openings 132 and 134 provides for communication of the ports 118 and 120 only with the respective portions of the muffler 102 on opposite sides of the partition 130. Thus. the interior of the muffler 102 can be viewed as a duct extending from the input port 118 between the partition 130 and the sidewall 122. the duct bending back around the partition 130 at the end wall 128, and then continuing between the partition 130 and the sidewall 124 to the output port 120. Thus, the duct has a U-shaped configuration. Within the duct, the air flows in undulating fashion among the baffles according to the foregoing description of the serpentine corridor.

Communication of the input port 119 and the output port 120 to opposite sides of the partition 130 is shown best in Fig. 14. An arrow 136 passes through the opening 132 to indicate the f low of air from the input port 118 into the portion of the U-shaped duct defined by the top wall 106, the bottom wall 104, the partition 110, and the sidewall 122. An arrow 138 in the opening 134 indicates the flow of air into the output port 120 from the portion of the Ushaped duct defined by the top wall 106, the bottom wall 104, the partition 130, and the sidewall 124. In the view of Fig. 14, the opening 132 is- displaced to the right of the common axis of the ports 118 and 120, and the opening 134 is displaced to the left of the common axis of the ports lie and 120. Fig. 14 also shows the serial interconnection of the muffler 102 between the upper tubular portion 110 and the lower tubular portion 108 of the breather conduit 96.

The cross-sectional view of the muffler 102, presented in Fig. 15, demonstrates the flow of air through the muffler 102 in the undulating path of the serpentine corridor, the air flow undulating in an up and down motion along a vertical plane. Fig. 15 also shown the coaxial arrangement of the muff ler ports 118 and 120. Arrows indicate the flow of air via the input port 118 into the muffler 102, and the outflow of air from the muffler 102 via the output port 120.

Pigs. 10 and 13-15 also show details in the construction of the valve 112. The valve 112 comprises a cylindrical cap 140 which encircles the tubular portion 110 of the breather conduit 96. The valve 112 includes a slot 142 cut into a sidewall of the tubular portion 110, and a circular aperture 144 disposed on a sidewall of the cap 140 in registration with the slot 142. The cap 140. the tubular portion 110. and the muffler input port 118 are disposed coaxially about a-common axis. The cap 140 may be. rotated manually about the common axis to align the aperture 144 with the slot 142 for a maximum flow of air through the valve 112 into the breather conduit 96. Further rotation of the cap 140 produces an offsetting of the aperture 144 relative to the slot 142 resulting in a constriction of the passage for air through the valve 112. The constriction of the passage for air through the aperture.144 reduces the flow of air through the valve 112 and the breather conduit 9-6. Thereby. by rotation of the cap 140. any desired rate of air f low can be selected up to the maximum value of the rate of flow.

As shown in Figs. 10 and 11, the muffler 102 can be manufactured readily from two plastic parts, each of which is readily molded. One of these parts comprises the bottom wall 104 with the baffles 114 and the port 120 constructed thereon. The second part comprises the top wall 106 with the walls 122, 1241 126, and 128 plus the baffles 116 and the tubular portion 110 constructed upon the top wall log. The walls 122, 124, 126, and 128 extend beyond the perimeter of the bottom wall 104 so as to grip the bottom wall 104 and thereby secure the top wall 106 in spaced-apart relation to the bottom wall 104. The muffler 102 can be opened for cleaning by lifting up on the semicircular end wall 1280 to overcome the friction of the walls 122, 124, 126, and 128 with the bottom wall 104. This permits a cleaning of the spaces among the baffles 114 and among the baffles 116. After cleaning, the muffler 102 is readily reassembled by pressing the top wall 106 towards the bottom wall 104 to secure the lower edges of the walls 122, 124g 126, and 126 to the perimeter of the bottom wall 104.

Figs. 16-18 show a muffler 102A which is an alternative embodiment of the muffler 102 described above. In contrast to the U-shaped duct of the muffler 102, the muffler 102A is constructed with a linear duct bounded by a roof or top wall 106A and a floor or bottom wall 104A interconnected by sidewalls 122A and 124A and end walls 126A and 128A. The walls 104A and 106A are spaced apart from each other and are parallel to each other. Baffles IIGA are disposed parallel to each other and extend from the top wall 106A to contact the bottom wall 104A. No baffles are present on the bottom wall 204A.

By way of contrast in the operation of the muffler 102 and in the operation of the muffler 102A, it is noted that while the undulations in the air conduction passage of the muffler 102 occur in an up and down fashion between floor and roof of the muf f ler 102, in the case of the muf f ler 102A, undulations in the air-flow passage occur from side to side between the sidewalls 122A and 124A. This is accomplished by extending the baffles 116A only partway from one of the sidewalls 122A or 124A to the other of the sidewalls 124A or 122A. By extending only partway to the opposite sidewall, each of the baffles 116A produces a window between the end of the baffle and the sidewall, the window also eing bounded by the top wall 106A and the bottom wall 104A. The windows serve as a part of the corridor within the duct for conduction of the air. By alternating the locations of the windows with respect to the sidewalls 122A and 124A for successive ones of the baffles 116A. the baffles extending from one of the sidewalls are interdigitated with the baffles extending from the other of the sidewalls to provide a serpentine corridor for passage of the air between an input port MA and an output port 120A of the muffler 102A. In view of the linear arrangement of the duct. the ports 118A and 120A are at opposite ends of the muffler 102A.. the input port 118 being located adjacent the semicircular end wall 128A,, and the output port 120A being located adjacent the end wall 126A.

The input port 118A may comprise a plurality of apertures such as the apertures 146. The output port 120A is a circular cylindrical section of tube communicating via a circular aperture in the bottom wall 104A to the interior of the muffler 102A. The apertures 146 are located in the opposite wall. namely the top wall 106A. The sidewalls 122K and 124A. and the end walls 126A and 128A extend from the top wall 106A to grip the perimeter of the bottom wall 106A by a friction fit. The walls 122A. 124Ai 126A. and 128A can be urged manually away from the bottom wall 104A for cleaning the muffler 102A. A plan view of the air flow path among the interdigitated baffles. between the input port 118A and the output port 120A, is shown In Fig. 18.

Pigs. 19-21 show a muffler 1028.which is another embodiment of the muffler 102. The muffler 102B includes certain features of themufflers 102 and 102A. and differs in other respects from the mufflers 102 and 102A. The muffler 1023 includes an air-carrying duct which has a Ushape, similar to the duct of the muffler 102. the U-shape of the duct of a muffler 1028 being provided by a partition 1308 which extends in a longitudinal direction of the muffler 102B in a manner analogous to that of the partition 130 of the muffler 102. Within the muffler 1028. the airflow passage follows a path which undulates in a side-toside manner similar to the air-flow passage within the muffler 102A.

The muffler 1023 comprises a top wall 106B and a bottom wall 104B. there being opposed sidewalls 122B and 1245. and two end walls 126B and 128B which extend from the top wall 106B to engage with and make frictional contact with the perimeter of the bottom wall 104B. An input port 1185 is located on the top wall 106B. opens Into the interior of the muffler 1023, and extends upwardly from the top wall 1063. An output port 120B islocated on the bottom wall 104B. opens into the interior of the muffler 102B, and extends downwardly from the bottom wall 104B. The two ports 118B and 120B have a generally cylindrical tubular shape, and are positioned coaxially. Also included within the muffler 1028 is a set of baffles 116B oriented transversely to the longitudinal partition 130B. the baffles 116B and the partition 130B extending from the top wall 106B to contact the bottom wall 104B.

The baffles 116B and the partition 130B are fully enclosed by the sidewalls 1228 and 1248 and the end walls 126D and 128B. The partition 130D in cooperation with the sidewall 122D define an input branch of the air-carrying duct. The partition 130D in cooperation with the sidewall 124D define an output branch of the air- carrying duct. The two branches of the duct are parallel to each other and are connected together by a passage defined by the semicircular end wall 128D to provide the U-shape to the duct. Within the input branch of the duct there are baffles 116D arranged serially with alternate ones of the baffles extending from the partition 130D partway to the sidewall 122B, the remaining baffles 116B extending from the sidewall 122D partway to the partition 130B. The baffles 116D extending from the partition 130D are disposed between and spaced apart from the baffles 1168 extending from the sidewall 122D to provide for interdigitation of the baffles of the input branch of the air-carrying duct.

The same arrangement of baffles is provided in the output branch of th b.-,.duct wherein alternate ones of the baffles 116D extend from the partition 1303 partway towards the sidewall 124B. and the remaining baffles 1169 extend from the sidewall 124B partway towards the partition 130. This provides for a serpentine corridor within the duct for the flow of air between the input port 1182 and the output port 1209 as shown in Fig. 21. In order to direct air from the input port 118D to the input branch of the duct, and in order to direct air from the output branch of the duct to the output port 1205. the two ports 1183 and 1203 are constructed. as described previously in Fig. 14. wherein the input and the output ports are provided respectively with reduced-size openings 132 and 134 disposed on opposite sides of the partition.. The muffler 1023 is operatively connected to the valve 112 In the same fashion as disclosed above for the muffler 102.

Figs. 22-24 show a muffler 102C which is a further embodiment of the muffler 102. The muffler 102C is similar to the muffler 102A in that both mufflers employ a linear duct between input and output ports disposed on opposite ends of the muffler. The muffler 102C is similar to the muffler 102 in that-both-aiifflers provide for an undulation of the air-flow path with the undulation occurring in a vertical plane between the roof and the floor of the muffler. The muffler 102C comprises a roof or top wall 106C and a floor or bottom wall 104C which is disposed parallel to and spaced apart from the top wall 106C. Sidewalls 122C and 124C and end walls 126C and 128C extend from the edges of the top wall 106C to engage with and to make frictional contact with the perimeter of the bottom wall 104C. As with the previously described c iments of the muffler. the frictional contact between the sidewalls and the end walls with the bottom wall permits the muf f ler 102C to be opened manually for cleaning of the muffler.

The top wall 106C in cooperation with the bottom wall 104C and the sidewalls 122C and 124C define a duct for carrying air, the duct extending in a linear conf iguration from an input port IISC located adjacent the end wall 128C to an output port 120C located adjacent the opposite end wall 126C. The input port 118C is configured as a single aperture in a top wall 1060. The output port 120C has a circular cylindrical configuration and opens via a circular aperture in the bottom wall 104C into the interior of the muffler 102C. A set of baffles IIGC is disposed on the top wall 106C. and a set of baffles 114C is disposed on the bottom wall 104C. The baffles 114C and 116C are oriented transversely to the longitudinal direction of the duct. The baffles 116C extend from the wall JL06C partway to the wall 104C. The baffles 114C extend from the wall 104C partway to the wall 106C, and are disposed between and apart from the baffles 116C. The arrangement of the baffles 114C and n6c provide an undulating passage for the flow of air, the passage having the configuration of a serpentine corridor as depicted in Fig. 24. Fig. 24 also shows arrows representing the flow of air via the inlet port IISC into the serpentine corridor followed by an exiting of the air via the output port 120C.

In each of the embodiments of the muffler, the walls, the baffles, and the muffler ports may be fabricated of plastic or rubber, both of these materials permitting manufacture by a process of molding the components of the muffler. The housing of the pump assembly may be fabricated of the same material employed in the fabrication of the muffler. In accordance with the practice in the construction of aquariums, the plastic or rubber materials employed in the manufacture of aquarium components are nontoxic to aquatic life. Such plastic or rubber is to be employed in the construction of the pump housing 64, the muffler 102 in its various embodiments,, and the valve 112.

Fig. 25 shows a fragmentary view of an aquarium 40A including a filter system 148- including the-power head 62 with a muffler 102, as described above. A further feature of this embodiment. namely, a clamp 150 is provided. The clamp ISO is adjustable for selecting a suitable location for the power head 62 in the tank SO and for securely holding the power head 62 in a selected location.

The aquarium 40A includes an undergravel filter 152 of conventional design, the filter 152 comprising a plate IS4 and a bed of filter material IS6 supported on the plate IS4. The plate IS4 is supported spaced apart from and parallel to a bottom 158 of the tank 50 by posts ISO (one of which is shown in Fig. 25). The plate IS4 has apertures 162 to allow water to f low through the f ilter material 156 into a chamber 164 of clean water beneath the plate 154, the water being pulled from the chamber 164 through a riser tube 166 to the water inlet port 20 of the power head 62. By operation of the power head 62, the water is drawn through the riser tube 166l is aerated, and then is expelled via the water outlet port 92 back into the main body of water of the aquarium 40A.

In accordance with a further feature of this embodiment, as shown in Figs. 25-27, the clamp 150 comprises a circular cylindrical ring assembly 168 having an upper flange 170 for engagement with the water inlet port 90 of the power head 62, and a lower flange 172 for engagement with the upper end of the riser tube 166. Centrally disposed within the ring assembly 169 is an internally threaded tube 174 and a threaded shaft 176 which engages with an interior threaded surface of the tube 174. Rotation of the shaft 176 about its longitudinal axis advances the shaft 176 along the tube 174. A flexible suction cup 178 and a knob 180 are mounted coaxially to an end of the shaft 176.extending outward of the tube 174. The knob 180 is securely fastened to the shaft 176 so that rotation of the knob 180 is imparted to the shaft 176 for advancing the shaft 176 along the tube 174. The knob ISO is readily grasped by a person to allow the person, by rotation of the knob ISO, to adjust the position of the suction cup 174 relative to the ring assembly 169. The upper flange 170 of the ring assembly If$ may be provided with an array of inwardly extending teeth 182 (Fig. 26) for secure engagement of the upper flange 170 with the outer surface of the water inlet port 90 of the pump assembly 62. The suction cup 176 is held on the end of the shaft 176 by a lip which permits the shaft 176 to rotate independently of the cup 178 thereby to permit adjustment of the location of the ring assembly 168 while the suction cup 178 adheres to the tank wall 54.

The operation of the clamp ISO is explained with reference to Figs. 25 and 27. Fig. 27 is particularly useful for explaining the operation of the threaded shaft 176 within the threaded tube 174,the tube 174 being sectioned in Fig. 27 to show threading on the shaft 176. The tube 174 extends diametrically across a central ring 184 of the ring assembly 168. In the operation of the ring assembly 168, the lower flange 172 is placed upon the upper end of the riser tube 166, the upper flange 170 is secured about the water-inlet port 90 of the pump assembly 62, and then the knob 180 is rotated to position the suction cup 178 relative to the ring assembly 166. The suction cup 178 is then pressed against the tank wall S4 to secure the clamp 150 to the tank wall S4. Thereupon, the knob 180 may be rotated further for final adjustment of the position of the power head 62 relative to the tank wall $4. This places the power head 62 in the position indicated in Fig. 3. The riser tube 166 may be fabricated of a plastic which can be placed appropriately to the undergravel filter.

Figs. 28 and 29 show a muf f ler 102D which is yet another embodiment of the muffler 102 described above. Instead of employing the baf f les of the previous embodiments of the muffler to provide the serpentine corridor, the muffler 102D employs a sequence of arcuate passages of differing radii of curvature. The arcuate passages,, indicated generally at 186, are connected serially to provide for a serpentine corridor for conducting air between an input port 118D and an output port 120D of the muf fler 102D. The input port 118D extends into the upper tubular portion 110 and the output port 120D extends into the lower tubular portion 108 of the air-breather conduit 96 (Fig. 8). The muffler 102D comprises a circular base is$ and a circular cover 190 disposed on top of the base lea and having a circular sidewall 192 extending from the cover 190 to overlap and make frictional contact with an outer peripheral surface 194 of the base 188. The frictional contact between the sidewall 192 and the peripheral surface 194 permits the cover 190 to be lifted manually away from the base 186 to permit cleaning of the muffler 102D.

Y Each of the arcuate passages 184 is formed partially by a continuous groove 196 formed in an upper surface 198 of the insert lee and a continuous rib 200 formed in a lower surface 202 of the cover 190. The groove and rib 196 and 200 are matingly arranged and are disposed in registration with each other so that the ribs partially enter the grooves to form the serpentine corridor comprising the series of the arcuate passages 186. Individual ones of the arcuate passages let are indicated in Fig. 29. in sequence of progressively smaller radii. by passages 1861- E. Successive ones of the arcuate passages 186 are connected by U-shaped end passages 204 of smaller radii than the arcuate passage 18M One end of the passage 1061 connects with the output port 120D. One end of the passage 146Z connects via a straight passage 206 to the input port 118D. The base 188 and the cover 190 may be fabricated of plastic or rubber material which facilitates manufacture by a molding process as has been described for the other embodiments of the muffler 102.

The views of Fig. 28 and 29 are drawn magnified. by a factor of approximately two times the actual size of the muffler 102D. The diameter of the largest arcuate passage 186A has a length of approximately one inch. This is substantially smaller than a wavelength of the sound emitted by the sucking in of the air. For example, at a sonic frequency of 1000 hertz, the wavelength is approximately one foot which is an order of magnitude greater than the diameter of the arcuate passage 196k. Thus, it is appreciated that the length of the various passages 186 are much smaller than that which is required for the construction of sonically resonant chambers as is done, by way of example, in the construction of mufflers for automotive engines. All embodiments of the muffler 102 operate in a non-resonant mode. The cross-sectional dimension of a passage 186 measures approximately 1 millimeter, a measure which is sufficiently small such that the passages 186 may be viewed acoustically as a capillary passage. Acoustic waves are rapidly attenuated in such a narrow passage and, accordingly, the muffler 102D is effective in silencing the sound of the incoming air. Similar cross-sectional dimensions are found in the other embodiments of the muffler 102. Also, the lengths of segments of the air transmission passages of the other embodiments of the muffler 102 are also much smaller than a wavelength of the sound. Therefore, all embodiments of the muffler operate in a nonresonant mode and serve to attenuate rapidly the sound produced by the incoming air.

The height of the muffler 102D, as measured along a central cylindrical axis, is much smaller than the outer diameter of the cover 190 to provide the muffler 102D with a low-profile configuration. The low-profile configuration and the overall dimensions of the muf f ler 102D allow the muf f ler 102D to be formed on top of, or as a part of, the top wall 69 (Fig. 8) of the housing 64. Thus, all embodiments of the muf fler 102 can be formed as an integral part of the housing $4.

It is to be understood that the above described embodiment of the invention are illustrative only, and that modifications thereof may occur to those skilled in the art. Accordingly, this invention is not to be regarded as limited to the embodiments disclosed herein.

The embodiments described hereinbefore are similarly described in United 1(ingdom Patent application numbers 9111463.7 and LZ9 "_"-1b Oc" 1 which include claims directed at features of the embodiments.

Claims

CLAIMS 1. A clamp for attaching an aquarium power head to a wall of an

aquarium tank, the power head including a water conduit and a pump for pumping water of the tank through the conduit, the power head having a housing enclosing the conduit and the pump, the housing being provided with inlet and outlet ports for the conduit, the inlet port being formed as a tubular sectioh, the clamp engaging with said tubular section for affixing said housing to said wall of the aquarium tank, said clamp comprising: a ring which mates with said tubular section; attachment means for engagement with said wall; and positioning means extending into said ring and engaging with said attachment means, there being space between said ring and said positioning means for the flow of water through the ring and into the inlet port.
2. A clamp according to claim 1, wherein said positioning means of said clamp Is adjustable for varying a distance between said ring and said tank wall, said positioning means including a rotatable knob located between said attachment means and said ring for allowing manual adjustment of said distance.
3. A clamp according to claim 2, wherein said positioning means of said clamp coffiprises an internally threaded tube extending diametrically across said ring and a threaded shaft disposed within said threaded tube and extending out of an end of said threaded tube to make rotational contact with said attachment means, said knob being fixed to said shaft for imparting rotation to said shaft wherein, upon rotation of said shaft, threads of -said shaft cooperate with threads of said threaded tube to displace said shaft along an axis of said shaft for adjusting said distance between said MR t ring and said tank wall.
4. A clamp according to any one of the preceding claims, wherein said attachment means is a suction cup.
5. A power head for insertion into an aquarium tank, the power head comprising a water conduit, a pump for pumping water of the tank through the conduit and having an impeller extending into the conduit, and a housing enclosing the conduit and the pump, the head having a clamp according to any one of the preceding claims with the ring being mated with the tubular section.
6. A power head according to claim 6, wherein said power head is operative with a riser tube located in said tank for supplying water to said inlet port of said power head and said ring extends away from said tubular section of said inlet port to engage an end of said riser tube, said ring serving as a fluid coupling between said riser tube and said inlet port.
7. A power head according to claims 5 or 6, the head being arranged to pump water through a filter system to return it to the aquarium and for aerating the returned water and comprising an air breather conduit communicating with said water conduit and extending from said water conduit to a source of entering air so that the flow of water through said water conduit entrains air from said breather conduit into the water in said water conduit.
8. A power head according to claim 7, wherein said breather conduit comprises a nonabsorbent muffler for silencing sound emitted by the entraining of the air in the water.
9. A power head according to claim 8, wherein said muffler is integral with said housing.
10. A power head according to claim 8 or 9, wherein said muffler comprises a serpentine corridor.
11. A power head according to claim 10 wherein said serpentine corridor comprises a circular path, with the path doubling back around itself to provide a series of concentric circles.
12. A power head according to any one of claims 5 to 9, comprising a sequence of arcuate passages having differing radii of curvature, said arcuate passages being serially connected to define a serpentine corridor.
13. A power head according to claim 12, wherein said arcuate passages are disposed side-by-side to provide a low-profile configuration to the muffler, the lowprofile configuration permitting a nesting of said muffler within an outer wall of said housing.
14. A power head according to claim 13, wherein one of said arcuate passages is nested within the next of said arcuate passages of said sequence, all of said arcuate passages being disposed in a common plane for a lowprofile configuration, said muffler comprising a base portion and a cover portion which are separable at said common plane to permit a cleaning of the muffler.
15. A power head according to claim 13, comprising a plurality of U-shaped passages and wherein each of said arcuate passages is connected to another of said arcuate passages by one of said U-shaped passages.
16. A power head according to claim 15, wherein each of U-shaped passages has a radius of curvature smaller than any of the radii of curvature of said arcuate passages.
17. A power head according to claim 10, comprising an array of interdigitated baffles, the baffles being spaced apart to define said serpentine corridor for conducting air from said source to said water conduit.
18. A power head according to claim 17, wherein said muffler has an elongated cross-section defined by parameters of width and height, the width being greater than the height to provide a low-profile configuration -1 i to the muffler, the baffles being disposed perpendicularly to a plane of said muffler.
19. A power head according to claim 18P wherein said baffles are elongated in a direction of said muffler plane, said muffler comprising a floor and a roof parallel to said muffler plane, said baffles extending from said floor to said roof, said corridor passing around an end of each baffle.
20. A power head according to claim 19A. wherein said baffles are elongated in a direction of said muffler plane, said muffler comprises a floor, a roof, and sidewalls connecting said floor and said roof, said floor and said roof being parallel to said muffler plane, said baffles extend from a first of said sidewalls to a second of said sidewalls opposite said first sidewall, and alternate ones of said baffles extend from said floor to form windows with said roof, the remaining ones of said baffles extending from said roof to form windows with said floor, said corridor passing through said windows.
21. A power head according to claim 20, wherein said baffles are elongated in a direction of said muffler plane, said baffles extend from a floor to a roof of the muffler, and alternate ones of said baffles extend from a first of sidewalls of the muffler to form windows with a second of said sidewalls opposite said first sidewall, the remaining ones of said baffles extending from said second sidewall to form windows with said first sidewall, said corridor passing through said windows.
22. A power head according to any one of claims 10 to 21, comprising an inlet port and an outlet port for the conduction of air through said corridor, said inlet port extending outward from said housing and said outlet port extending within said housing to an air entraining apparatus, said Inlet-port including a valve accessible outside of said housing for adjusting a flow rate of the air conducted through said serpentine corridor.

4 a Amendments to the claims have been filed as follows - 3C1 ring and said tank wall. 4. A clamp according to any one of the preceding claims, wherein said attachment means is a suction cup. 5. A power head for insertion into an aquarium tank, the power head comprising a water conduit, a pump for pumping water of the tank through the conduit and having an impeller extending into the conduit, and a housing enclosing the conduit and the pump, the head having a clamp according to any one of the preceding claims with the ring being mated with the tubular section. 6. A power head according to claim 6, wherein said power head is operative with a riser tube located in said tank for supplying water to said inlet port of said power head and said ring extends away from said tubular section of said inlet port to engage an end of said riser tube, said ring serving as a fluid coupling between said riser tube and said inlet port. 7. A power head according to claims 5 or 6, the head being arranged to pump water through a filter system to return it to the aquarium and for aerating the returned water and comprising an air breather conduit communicating with said water conduit and extending from said water conduit to a source of entering air so that the flow of water through said water conduit entrains air from said breather conduit into the water in said water conduit. 8. A power head according to claim 7, wherein said breather conduit comprises a non-water absorbing muffler for silencing sound emitted by the entraining of the air in the water. 9. A power head according to claim 8, wherein said muffler is integral with said housing. 10. A power head according to claim 8 or 9, wherein said muffler comprises a serpentine corridor. 11. A power head according to claim 10 wherein said