Abstract:
A heating and pumping device for liquids, in particular for water of aquariums, the device comprising a pump ( 24 ) having a pump body ( 32 ) and a thermo-heating element ( 26 ) having a thermo-heating body ( 60 ). There is a casing ( 22 ) which contains both the pump ( 24 ) and the thermo-heating element ( 26 ) such that a passage section ( 102 ) for water is defined between the thermo-heating element ( 26 ) and the casing ( 22 ). To seal the electrical parts of the thermo-heating element ( 26 ) and to prevent damage, a sole sealed zone ( 100 ) filled with resin is created between the pump body ( 32 ) and the thermo-heating body ( 60 ). This resin filled sole sealed zone ( 100 ) obviates the need for using other less effective sealing elements and gaskets.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a heating and pumping device for liquids, in particular for water of aquariums, of the type comprising a pump and a thermo-heating element. 
     BACKGROUND OF THE INVENTION 
     Devices which consist of a pump used for circulating water, coupled to a thermo-heater allowing the water to be heated, are known. These devices can also be used in aquariums, in particular domestic ones in which it is necessary to provide a pump for circulating water in order to filter it, previously inserting a filter in the recirculating circuit; this permits also to oxygenate the water and to maintain the optimal conditions inside the aquarium for the surviving of fishes contained therein. Furthermore, for the same reason, it is necessary to maintain the water temperature between predetermined limits by a thermo-heater which depends on the type of fishes to be bred. Obviously the aquarium must contain fishes which necessitate water of the same type (salt or fresh water) which must be maintained at the same temperature. 
     On the market different kinds of pump exist, most of them of the centrifugaltype powered by an electric motor. Also different kinds of thermoheater exist, all of them utilizing an electric resistance for heating the water. Many improvements are made for both the pump and thermoheater, but always using these two fundamental elements. 
     An apparatus for pumping and filtering water for aquariums is disclosed in U.S. Pat. No. 3,635,344 filed on Aug. 21, 1970. This document concerns a pump and filter unit to be mounted on the wall of an aquarium by means of hooks. The unit comprises a housing mounted on the outside of the aquarium which contains a removable filter tank for filtering the water. A space is defined between the housing and the filter tank wherein, at the bottom, there are an electric heater for heating the water and a thermostat for controlling the water temperature. The unit also comprises a screw-type elevator mechanically connected to an electric motor placed on the top the elevator. The elevator is immersed in water so that the water is pumped into the filter tank and then it comes out from the bottom of the filter and it fills the space defined between the housing and the filter tank. The water is heated and goes into the aquarium by means of spillways made in the hooks. Producing the pump and the thermoheater separately involves high industrial costs and a long manufacturing time. 
     Bear in mind that these two elements in an aquarium are inconvenient and cumbersome, these troubling the field of vision, that is, they obstruct the clear visual inside the aquarium although these elements are located near the aquarium walls. 
     The thermo-heater has to measure the real temperature of water, hence it must not be positioned near the areas where water is prevented from circulating; therefore it is necessary to choose the right place for it that usually is near the pump. 
     Considering now the thermoheaters of the prior art, they generally consist of glass casing inside which an electric resistance is contained. Consequently they can be damaged because of the fragility of the material used; another drawback consists of the difficulty in providing suitable gaskets for preventing the water from penetrating inside which hinders the correct operation. This involves making suitable housing seats for the gaskets, using gaskets which allow a high degree of sealing and finally an assembly cycle to mount the whole. Finally, the temperature sensor of the thermoheater interferes with the heat which rises upwards in different ways according to the manner the thermoheater is positioned; usually the setting is made when the thermoheater is vertically positioned, therefore it is necessary to put it always in the upright position. 
     SUMMARY OF THE INVENTION 
     The aim of the invention is therefore to conceive a device which eliminates the drawbacks cited above with reference to the prior art. The device made in such way must be simple, reliable and cheap. 
     The aim is achieved by means of a device of the above-mentioned type comprising a pump and a thermoheater element, characterized in that said pump and said thermoheater element are contained inside a casing. The device becomes very compact, including in a sole apparatus both the function of the pump and the thermo-heater so that many advantages derive: easy to produce, quick to manufacture, troubles in the field of vision reduced to a minimum and cost lower than the sum of the individual costs of the pump and thermo-heater. 
     Because of the integration between the thermoheater and the pump, there is no problem in locating the thermoheater in the right position. In particular, between the thermoheater and the casing a passage section for water is defined. The thermoheater element comprises a hollow body inside which resistance means are housed, this body is integral with and in communication to the pump body which houses the statoric part of the pump in order to form a sole sealed zone. 
     In such a way the principle components of the device are few, so reducing the final cost of the product. Filtering means must also be placed between the thermo-heater hollow body and the casing, this means preferably consists of a cartridge in a porous material so extending the functions of the device making it more appreciable, above all, for the customers who want to reduce the total expense of an aquarium. 
     In order to seal the pump body with the hollow body of the thermoheater element, so forming said sealed zone, a resin is used which makes unnecessary the use of sealing elements or gaskets to prevent water from penetrating inside the thermoheater simplifying further the assembly and production phases, guaranteeing at the same time a perfect seal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other advantages result more evidently from the following detailed description of a preferred embodiment made for an illustration and not limiting scope with reference to the following enclosed drawings in which: 
     FIG. 1 is a schematic elevation cross-section of a device according to the present invention; 
     FIG. 2 is an elevation cross-section of the device of FIG. 1 without the casing; 
     FIG. 3 is an enlarged view of a particular of FIG. 2; 
     FIG. 4 is a perspective view of the pump body containing the rotoric part partially moved; 
     FIG. 5 is a perspective view of the hollow body of the thermo-heater element; 
     FIG. 6 is a top view of the electric resistance; 
     FIG. 7 is a perspective view of the presser; 
     FIG. 8 is a perspective view of the casing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 a filtering and pumping device is indicate with  20 . The device  20  comprises a casing  22  inside which a pump  24  is housed. The pump is connected to a thermoheater element  26 . 
     From FIGS. 2 and 4, one notes that the pump  24  comprises a pump body  32 , a statoric part  34  and a rotoric part  36 . The pump body is essentially parallelepipedic and has a first housing  38  designed to house the statoric part  34  of the pump  24  and a second housing  40  designed to house the rotoric part  36  of the pump  24 . The statoric part  34  consists essentially of a support  42  around which an electric winding  44  is provided, whereas the rotoric part  36  comprises a pin  46  on which a rotary impeller  50  is mounted and connected to a permanent magnet  48  with double-polarity. The water flows into the second housing  40  and then to the rotoric part  36  of the pump  24  by means of an entry opening  52  which can be closed by a manually movable tongue which acts like a valve enabling the circulating water flow to vary its rate. 
     From FIGS. 2,  3  and  5 , it can be seen that the thermoheater element  26  comprises an hollow and cylindric thermo-heating body  60 , an electric resistance  62 , a pressing element  64 , a thermostat  66 , a temperature sensor  68  and a temperature controlling mechanism  70 . The thermo-heating body  60  has two opposite ends  60   a,   60   b : the first end  60   a  is closed, whereas the second end  60   b  widens forming a square inlet. 
     From FIGS. 2,  3  and  6 , it can be noted that the electric resistance  62  is wound up inside the thermo-heating body  60 , the resistance  62  consists of a insulating material sheet on which two parts are identified: a first half  62   a , and a second half  62   b  which comprises a PTC-type electric resistance (positive temperature coefficient). The PTC-type resistance comprises a flexible laminar support made of thermo-resistant and electrically insulating material above which an electrically resistive material layer is applied, wherein the electrically resistive layer is made of ink printed on the support so as to form a plurality of tracks or trails as shown in FIG. 6 which are electrically supplied. The main feature of PTC is that the resistance value increases when temperature increases so as to limit the electric current, thereby preventing problems due to overheating. The electric resistance  62  is wound up inside the thermo-heating body  60  beginning with the first half  62   a  so that the first half  62   a , which acts as an insulator for the PTC-type electric resistance  62   b , is interposed between the thermo-heating body  60  and the PTC-type electric resistance  62   b . In such a way a double electrical insulation is provided between the water circulating outside the thermo-heating body  60  and the PTC-type electric resistance  62   b : the thermo-heating body  60  and the first half  62   a.    
     From FIGS. 2,  3  and  7  one notes that a cylindrical pressing element  64  abuts upon the electric resistance  62  so forcing a continuous and uniform contact between the PTC-type electric resistance  62   b  and the inner surface of the thermo-heating body  60 , thus obtaining an optimal thermal exchange. 
     From FIG. 2, it can be noted that the thermostat  66  is housed into the square end  60   b  of the thermo-heating body  60  and is electrically connected to the PTC-type electric resistance  62   b  and to the temperature sensor  68 . The temperature sensor  68  is positioned near the square end  60   b  of the thermo-heating body  60  (see FIG. 3) and is interposed between the first half  62   a  and the second half  62   b  of the electric resistance  62  at a zone  74  (as shown in FIG. 6) that is, clear of the PTC-type electric resistance  62   b . The sensor  68  is of the NTC-type (negative temperature coefficient), that is, a resistive element whose resistance value decreases when the temperature increases. The temperature controlling mechanism  70 , as represented in FIG. 2, comprises a rotatable pin  80  essentially positioned in an axial manner with respect to the thermo-heating body  60  and having two opposite ends  80   a , 80   b : a first end  80   a  which projects out of the closed end  60   a  of the thermo-heating body  60  and a second end  80   b  acting onto a trimmer  82  connected to the thermostat  66  so as to predetermine the required temperature for water. An O-ring gasket  84  is provided onto the first closed end  60   a  of the cylindrical and hollow body  60  where the rotatable pin  80  projects out of the thermo-heating body  60 , in order to prevent water from coming inside. 
     From FIGS. 2,  3  and  4  one notes that the pump body  32  has a seat  90  for housing an electric supply  92  wire which enters into the body and is connected to the electric winding  44  of the statoric part  34  of the pump  24  and to the thermostat  66  which is electrically connected to the PTC-type electric resistance  62   b . The housing  38  is entirely filled with liquid resin which incorporates the statoric part  34  of the pump  24  and the thermostat  66 ; subsequently, the pump body  32  and the thermo-heating body  60  are assembled by inserting the square end  60   b  of the thermo-heating body  60  inside the first housing  38  of the pump body  32  which is shaped so as to perfectly couple with the square end  60   b . The resin solidifies and seals the pump body  32  with the thermo-heating body  60  preventing water from entering inside, so defining a sole sealing zone  100 . 
     From FIGS. 1 and 8, one can see that the casing  22  is essentially parallelepipedic and shaped so as to house not only the pump  24  and the thermo-heating element  26 , but also to define a passage  102  to let the water flow between the casing and the thermo-heating body  60 . The casing  22  has an opening  104  by which water is sucked in and an exit duct  106  from which pumped water comes out. From FIG. 1, it can be seen that a cartridge filter  72  made of porous material is interposed between the casing  22  and the thermo-heating body  60 . 
     In order to use the device, it is sufficient to dip it in water and connect the electric supply wire  92  to an electric source. The pump  24  immediately starts up and makes water recirculate filtering it thanks to the cartridge filter  72 , while the PTC-type electric resistance  62   b  operates when the sensor  68  signals a temperature of the water lower than the temperature predetermined by the thermostat  66  thanks to the control mechanism  70 . Rotating the end  80   a  of the rotatable pin  80  the temperature predetermined by the thermostat  66  is controlled and the temperature of water is changed. 
     From the above disclosure, the simplicity of construction of the device is illustrated, particularly if one considers that the device can be supplied without the cartridge filter  72 , with a predetermined temperature of the thermostat  66 , and without the mechanism  70  for the control of the temperature. Optional use of the temperature control mechanism  70  permits increased versatility of device manufacture, whereas the use of the filter  72  makes the product more suitable and cheap for the market, for example for the domestic aquariums sold to children. 
     Another advantage is due to the fact that the temperature sensor  68  measures the temperature upstream of the thermo-heating element  26  with respect to the direction of the water flow and, consequently, it measures the real temperature of the aquarium water; furthermore, thanks to the clear zone  74  where the temperature sensor  68  is positioned, it is not thermically affected by the proximity of the thermo-heating element  26 . Moreover, the device can be positioned in any position because the temperature sensor  68  measures always the same water temperature independently of its position. For example it is possible to use a different and larger casing which entirely encloses the device so as to house the cartridge filter within the device and said casing and provides a larger passage section  102  for water.