Abstract:
A filter element includes a bag ring which is snap fitted into the filter vessel sidewall and retains both the filter element and a filter basket in the desired location in the vessel until removed.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention disclosed herein relates generally to filters for removing particulates from liquids. More particularly the invention relates to a filter in which the filter element or bag may be snap fit into the filter vessel.  
       BACKGROUND OF THE INVENTION  
       [0002]     It is known to have a filter assembly including a vessel that contains a filter element interposed between fluid flow between an inlet and an outlet in the vessel. In such an arrangement it is common for a filter element to include two basic parts: a filter bag of a generally fibrous material for filtering out particulates from the fluid, and a bag ring secured to the edges of the bag for retaining the filter bag in position within the filter vessel. It is also common to have a porous rigid basket within the vessel between the bag and the outlet in order to support the bag.  
         [0003]     A problem with the current art as described, however, is that the filter element and basket often tend to float out of position when fluid flow is stopped through the filter assembly. This problem is exacerbated when the basket is composed of plastic instead of a heavier metal. Therefore it would be advantageous to have a filter assembly which can be economically manufactured and which includes a filter element that will maintain its position within the vessel when fluid flow is stopped.  
       SUMMARY OF THE INVENTION  
       [0004]     A filter assembly is disclosed in which a filter element is snap fit into the filter vessel wall. The snap fit is obtained by means of a protrusion or ridge on the exterior side of the filter bag ring which may be resiliently snap fitted into a complementary recess or groove on the interior side of the vessel sidewall. The snap fitted bag ring retains both the filter element and the filter basket in position.  
         [0005]     An object of the invention is to provide a filter assembly of economical construction which includes a filter element that will not float out of position within the filter vessel when fluid flow has stopped. Another object of the invention is to provide a filter element that will maintain its position within a filter vessel independently of the vessel lid or cover. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     These and other aspects of the invention will be apparent from the following detailed description, with reference to the figures in which:  
         [0007]      FIG. 1  is a partial cut away side view of a filter assembly showing the filter element and filter basket in position within the filter vessel;  
         [0008]      FIG. 2  is a side view in partial cross section of the filter bag ring of the filter element of  FIG. 1 ;  
         [0009]      FIG. 3  is a top view of the filter bag ring;  
         [0010]      FIG. 4  is a detailed cross section of the bag ring and vessel wall before the filter element is fully inserted;  
         [0011]      FIG. 5  is a detailed cross section showing the filter element fully inserted without fluid flow through the vessel; and  
         [0012]      FIG. 6  shows the bag ring in position within the vessel wall with fluid flow through the vessel. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]     Turning now to the figures, a filter assembly  9  as depicted in  FIG. 1  includes a vessel  10 , a filter element  12 , and a rigid basket  14 . Vessel  10  includes a sidewall  16 , bottom wall  18 , and removable cover or lid  20 . An inlet  22  and an outlet  24  in vessel  20  allow fluid flow through the vessel. Vessel sidewall  16  has a generally smooth interior surface except for a shoulder  26  and a groove or notch  28 . Shoulder  26  extends around the inner periphery of sidewall between inlet  22  and outlet  24  and is upwardly inclined near its inner or central edge. Groove  28  is recessed into sidewall  16  slightly below shoulder  26  and extends around the inner periphery of the sidewall.  
         [0014]     Basket  14  supports filter element  12  within the vessel. Basket  14  is of porous construction for allowing flow of liquid therethrough and is preferably made of plastic. Basket  14  is carried within vessel  10  below shoulder  26 . The upper rim  15  of basket  14  is preferably located next to the interior surface of sidewall  16  below groove  28  with the basket extending toward outlet  24 .  
         [0015]     Filter element  12  includes a filter bag  30  and a bag ring  32 . Filter bag  30  is composed of a porous cloth-like filtration material such as woven cloth or blow-molded resins. The mouth of filter bag  30  is secured around its upper edge to bag ring  32  by any suitable process such as heat sealing or gluing.  
         [0016]     Turning now to  FIGS. 2 and 3 , bag ring  32  is of generally circular form sized to fit against the inner surface of vessel sidewall  16  at shoulder  26  to form a liquid seal between the bag ring and the vessel sidewall. Bag ring  32  is preferably made of a pliable or flexible, yet shape retaining or resilient material such as nylon or polypropylene. Bag ring  32  has a stepped sidewall defining a horizontal shoulder  34  extending between an upper sidewall  33  and a lower sidewall  35 . An outer peripheral flange  36  is downwardly angled from upper ring sidewall  33 . Annular ribs  38  extend about the outer periphery of upper ring sidewall  33 . Upper ring sidewall  33  is sized to seat against vessel sidewall  16  below shoulder  26 . Ribs  38  are co-planar and angularly spaced intermittently around bag ring, but a single continuous circumferential rib could also be used. In the depicted embodiment, four ribs  38  angularly spaced at right angles from each other extend intermittently about the upper ring sidewall  33 . Flange  36  forms a recess  40  between the flange and upper ring sidewall  33 . A pair of handles  42  for gripping the filter element span across interior portions of bag ring  32 .  
         [0017]     With basket  14  placed within vessel  10  below shoulder  26 , filter element  12  is pushed into vessel  10  with its flange  36  seating upon shoulder  26  and ribs  38  in bag ring  32  snap-fitting into groove  28 . As filter element  12  is inserted into vessel  10  ( FIG. 4 ), ribs  38  cause upper ring sidewall  33  be flexed inwardly as the ribs pass over the vessel side wall below shoulder  26 . When ribs  38  reach groove  28 , upper ring sidewall  33  flexes back against vessel sidewall  16  with ribs  38  projecting into groove  28  and with bag ring flange  36  being slightly flexed against shoulder  26  to urge ribs  38  into contact with the upper edge of the groove as shown in  FIG. 5 . Ribs  38  prevent bag ring  32  and basket  14  from floating out of position when fluid flow through the filter assembly is terminated. The upper interior edge  39  of inclined shoulder  26  fits into recess  40  with flange  36  overlying and contacting the shoulder. The upper rim  15  of basket  14  is located below shoulder  34  and preferably between vessel sidewall  16  and lower bag ring sidewall  35 . The snap fit bag ring  32  with its ribs  38  fitted into side wall grooves  28  prevents basket  14  from floating out of position without requiring other retaining means for the basket or the bag ring.  
         [0018]     During fluid flow through the vessel ( FIG. 6 ), bag ring flange  36  is urged fully downwardly against shoulder  26 , causing the inclined edge  39  of the shoulder to nest within bag ring recess  40  to create a liquid seal between bag ring  32  and vessel sidewall  16  and to assist in maintaining the bag ring in position during fluid flow through the filter assembly.  
         [0019]     To remove filter element  12  from vessel  10 , bag ring  32  is pulled out of vessel  10  by using handles  42  to urge ribs  38  out of groove  28  and past shoulder  26 .  
         [0020]     The above subject invention is not to be limited to the details given above for the preferred embodiment, but may be modified within the scope of the impending claims.