Abstract:
A filter sponge having a replace-indicating function is mainly used in an aquatic filter to filter aquatic breed water. The filter sponge includes a sponge body ( 10 ) centrally defining therein a vertical passage  11 . A replace-indicating mechanism ( 20 ) is located at a top side of the vertical passage. When the filter sponge is used to filter breed water, the replace-indicating mechanism indicates to the user the state of the filter sponge, by which the user can be aware of whether the filter sponge needs to be replaced.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of The Invention  
         [0002]     The present invention relates generally to a filter sponge with a replace-indicating function, and more particularly to a novel filter sponge which defines a vertical passage and comprises a replace-indicating mechanism located at a top side of the vertical passage to indicate that the filter sponge has been polluted and needs to be replaced.  
         [0003]     2. Description of Related Arts  
         [0004]     Water filters having filter sponges have been widely used in aquatic breed. One of such water filters typically defines therein a cavity having an entrance. For most of such water filters, the filter sponge locates beneath the entrance of a cavity. Therefore, after breed water enters the water filter, the breed water must penetrate the filter sponge downwardly before it flows back into the aquarium via an exit formed below the filter sponge. By passing the breed water through the filter sponge, the filter sponge can thus filter and clean the breed water.  
         [0005]     The simply constructed filter sponge as described above indeed can filter and clean the water. However, because the breed water penetrates the filter sponge from a top side toward a bottom side of the filter sponge, contaminations the filter cleans from the water will be easily accumulated on the top side of the filter sponge. If this accumulation increases greatly, the breed water can hardly penetrate the filter sponge downwardly. As a result, the overall filtering performance of the filter sponge will decrease, even if the bottom section of the filter sponge can still be used. Due to this problem, the filter sponges of this kind as described above are often criticized by their users.  
         [0006]     As an attempt to resolve this problem, the filter sponge is proposed to be located above the entrance. To avoid an excursion of the filter sponge away from its original position due to the floatage of the breed water, the filter sponge defines therein a vertical passage acting as a buffering zone to lessen the floatage. Therefore, the breed water flows into the vertical passage from a bottom side of the filter sponge, and further penetrates through the wall portion of the filter sponge, by which the contaminated water is cleaned. For a fresh filter sponge, once the breed water enters the vertical passage, it directly penetrates through a bottommost section of the wall portion of the filter sponge. Therefore, the filter sponge at the bottommost section thereof forms a filtering zone. As this bottommost section of the filter sponge continuously accumulates the contaminations, the breed water moves along the vertical passage to a higher level, which results in an upward movement of the filtering zone for further filtering operation. Thus, this kind of filter sponge has an improved filtering performance and lifetime.  
         [0007]     However, the filter sponge is generally arranged in a closed filter. If the user fails to timely check the filter sponge, it may often happen that, the filter sponge has also been completely polluted and lost its filtering function but the user has not been aware of that. Thus, the overall filtering performance of the filter sponge will decrease. What is needed, therefore, is to provide a filter sponge that the user can easily and effectively check whether it can still be used to filter water or not.  
       SUMMARY OF THE INVENTION  
       [0008]     A primary object of the present invention is to provide a filter sponge having a replace-indicating function which comprises a sponge body defining therein a vertical passage, and a replace-indicating mechanism located at a top side of the vertical passage. The replace-indicating mechanism has an indicator to achieve an indication function in a floating manner by which the user can be indicated that the sponge body needs to be replaced.  
         [0009]     A secondary object of the present invention is to provide a filter sponge having a replace-indicating function which comprises a sponge body defining therein a vertical passage, and a replace-indicating mechanism located at a top side of the vertical passage. The replace-indicating mechanism has a cover to achieve an indication function in a pivoting manner by which the user can be indicated that the sponge body needs to be replaced. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is an isometric, exploded view of a filter sponge having a replace-indicating function in accordance with embodiments of the present invention;  
         [0011]      FIG. 2  is a schematic view showing an initial use state of the filter sponge of  FIG. 1  assembled to a filter according to a first embodiment;  
         [0012]      FIG. 3  is a schematic view showing a state of the filter sponge of  FIG. 1  that needs to be replaced according to the first embodiment;  
         [0013]      FIG. 4  is a schematic view showing an initial use state of the filter sponge of  FIG. 1  assembled to a filter according to a second embodiment; and  
         [0014]      FIG. 5  is a schematic view showing a state of the filter sponge of  FIG. 1  that needs to be replaced according to the second embodiment. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0015]     Referring to  FIG. 1 , a filter sponge of the present invention is used in an aquatic filter  1  ( FIG. 2  through  5 ) to filter aquatic breed water. The filter sponge in accordance with a first embodiment of the present invention comprises a sponge body  10  and a replace-indicating mechanism  20 . The sponge body  10  is configured to be in a form of a column, and centrally defines therethrough a vertical passage  11 .  
         [0016]     The replace-indicating mechanism  20  comprises a base member  21 , a buoy  22  and a buoy positioning member  23 . The base member  21  comprises a horizontal top portion  211  for being placed on a top side of the sponge body  10 . The horizontal top portion  211  defines a thought hole  212  aligned with the vertical passage  11 . A plurality of connecting stripes  214  extends downwardly along an inner wall of the sponge body  10 . Spaces (not labeled) are formed between two adjacent connecting stripes  214 . A horizontal bottom portion  213  connects free bottom ends of the connecting stripes  214 . A though opening  215  is centrally defined in the horizontal bottom portion  213 .  
         [0017]     The buoy  22  comprises a suspending body  221  which can sit on the horizontal bottom portion  213  at the through opening  215  thereof, and an indicator  222  extending upwardly from the suspending body  221 . The indicator  222  has such a weight as to balance the floatage of the breed water; so that the floatage of the breed water will not move the buoy  22  upwardly when the buoy  22  is disposed in the filter  1 .  
         [0018]     The buoy positioning member  23  comprises a horizontal plate  231  which can be positioned at the through hole  212  of the horizontal top portion  211 . The horizontal plate  231  defines a through aperture  232  for allowing the indicator  222  to vertically move therein.  
         [0019]     Referring to  FIGS. 2 and 3 , the filter  1  comprises a support base  2  for supporting and positioning the filter sponge  10 . When the filter sponge is assembled to the support base  2 , the level of the internal water of the filter is set to be lower than a topmost position of the filter sponge. Since the weight of the indicator  222  is designed so as to balance the floatage of the water, the suspending body  221  can still sit on the horizontal bottom portion  213  as illustrated in  FIG. 2 .  
         [0020]     In use, the breed water in an aquarium (not shown) is pumped into the filter  1  by a pump  3  located in the aquarium. The breed water level rises along the vertical passage  11  of the sponge body  10 . In  FIG. 2 , the sponge body  10  is a fresh one. That is, pores of sponge body  10  have not been obstructed by the contaminations of the breed water. Therefore, once the breed water enters the vertical passage  11 , it directly penetrates through a bottom section of the wall portion of the sponge body  10 , by which the breed water is filtered and cleaned. Then, the cleaned water flows back into the aquarium via an exit  4  of the filter  1 .  
         [0021]     It should be understood that, in initial use, the filtering zone of the filter sponge locates at the bottom section of the sponge body  10 . Therefore, the contaminations in the breed water are only accumulated at the bottom section of the sponge body  10  in the initial use. However, as the using time goes, the bottom section of the sponge body  10  gradually loses its filtering function because the contaminations are continuously accumulated thereat. The breed water then moves upwardly along the vertical passage  11  to a higher level, which results in an upward movement of the filtering zone. When the filtering zone moves to the topmost section of the sponge body  10  as illustrated in  FIG. 3 , the upwardly moving breed water pushes the suspending body  221  to move upwardly. The upwardly moving breed water then passes spaces between the adjacent connecting stripes  214  and penetrates through the sponge body  10 , by which the breed water is filtered and cleaned. In addition, since the suspending body  221  is pushed to move upwardly, the indicator  222  on the suspending body  221  is pushed to move upwardly and extend through the through aperture  232  of the horizontal plate  231 . When the user sees the indicator  222  extending beyond the horizontal plate  231 , the user can realize that the filter sponge needs to be replaced. In this way, the filter sponge of the first embodiment can perform an indication of replacing the filter sponge to the user  
         [0022]     Referring back to  FIG. 1 , in a filter sponge in accordance with a second embodiment of the present invention, the indicator  22  and the buoy positioning member  23  of the first embodiment may be omitted. Instead, a cover  25  is pivotably attached to the horizontal top portion  211  with a pivot structure. The cover  25  coves the through hole  212  of the horizontal top portion  211  in a closed position wherein the through hole  212  is closed at a top side thereof. The cover  25  forms a set of axles  251  at one side thereof. The horizontal top portion  211  further forms a cover holder  216  pivotably receiving the axles  251  of the cover  25  therein to constitute the pivot structure. Therefore, the cover  25  is able to pivot with respect to the cover holder  216  upwardly to an open position wherein the top side of the through hole  212  is open.  
         [0023]     Referring to  FIGS. 4 and 5 , the filter sponge of the second embodiment is also assembled to the support base  2 , with the level of the internal water of the filter  1  being lower than a topmost position of the filter sponge. Since the cover  25  locates above the internal water level, the cover  25  completely covers the through hole  212  of the horizontal top portion  211  as illustrated in  FIG. 4 .  
         [0024]     As described above, the sponge body  10  is a fresh one. Therefore, once the breed water enters the vertical passage  11 , it directly penetrates through a bottom section of the wall portion of the sponge body  10 , by which the breed water is filtered and cleaned. Then, the cleaned water flows back into the aquarium via the exit  4  of the filter  1 . That means, in initial use, the filtering zone of the filter sponge mainly locates at the bottom section of the sponge body  10 . Therefore, the contaminations in the breed water are only accumulated at the bottom section of the sponge body  10  in the initial use.  
         [0025]     However, as the using time goes, the bottom section of the sponge body  10  gradually loses its filtering function because the contaminations are continuously accumulated thereat. The breed water then moves upwardly along the vertical passage  11  to a higher level, which results in an upward movement of the filtering zone. When the filtering zone moves to the topmost section of the sponge body  10  as illustrated in  FIG. 5 , the upwardly moving breed water passes spaces between adjacent connecting stripes  214  and penetrates through the sponge body  10 , by which the breed water is filtered and cleaned. When the sponge body  10  is completely obstructed by the accumulated contaminations, the breed water moves further upwardly through the through hole  212  of the horizontal top portion  211 . As a result, the cover  25  is pivoted upwardly by the upwardly moving breed water into the open position as illustrated in  FIG. 5 . When the user sees the cover  25  in the open position, the user can realize that the filter sponge needs to be replaced. In this way, the filter sponge of the second embodiment can perform an indication of replacing the filter sponge to the user.  
         [0026]     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.