FILTER

Abstract: The invention relates to a filter called spin-on filter (1) for filtering a flowing substance, especially to a filter for hydraulic liquid or lubricating oil in combustion motors. The filter comprises a casing (7), which is openable at one end, a substantially cylindrical replaceable filter means (19) fitted inside the casing, the flow to be filtered having been arranged to pass through the filter means mantle, and a collar (16) for connecting the filter with a device assembly (6), which includes inlet and outlet ducts (4, 5) for flow to be filtered. In accordance with the invention, the filter comprises a support member (10) forming a solid extension of the collar (16) and consisting of an axial spindle (11) inside the filter means (19) and of an end flange (13) at its end opposite to the collar, the periphery of the end flange being tightly sealed against the inner wall of the casing (7) such that the support member will receive the internal pressure within the casing axially. The joints between the support member (10) and the collar (16), and the collar (16) and the device assembly (6), respectively, may consist of threaded joints (15, 2, 3). As the flow to be filtered passes from the outside to the inside of the filter means (19), the means may bear against a perforated support pipe (17) extending inside the means from the collar (16) to the end flange (13) of the support member.

Description: Filter This mvention relates to a filter for filtering a flowing substance, such as oil, comprising a casing, which is openable at one end, a substantially cylindrical, replaceable filter means fitted within the casing, the flow to be filtered being arranged to pass through the mantle of the filter means, and a collar for connecting the filter to the device assembly, which includes inlet and outlet ducts for the flow to be filtered. One of the applications of encased cylindrical filters is filtering lubricating oil in combustion motors so as to keep the oil free of impurities in operation. A second typical field of application for filters of this type is filtering hydraulic liquid in hydraulic systems. Since the filter is fouled in operation and has to be replaced at intervals, the filter casing must be removable from the device assembly to which it is attached. There are previously known oil filters, in which the filter means and the surrounding casing have been constructed as a solid unit, replaceable as such. However, such a design is a waste of material and also produces waste in abundance. From an ecological viewpoint, it is preferable to devise a casing that can be opened, so that the clogged filtering means alone is replaced and the casing including a replacement means is put back in position in the device assembly. FI patent application 955127 is cited as an example of such a design, in which the assembled oil filter described comprises a cylindrical, replaceable filter means, a perforated support pipe within the means, a collar as an extension of this pipe, a casing surrounding the means and a joint ring at the casing mouth. The collar has a thread, which connects the assembled filter with the device assembly, simultaneously providing a sealing between the joint ring and the device assembly. In conventional filters ofthe type above, the casmg must resist axial stress caused by the high pressure of the substance to be filtered, such as oil or hydraulic liquid, and for this reason the casing must be made of a rigid sheet mateπal. The perforated support pipe must also be stiff enough to withstand the internal axial stress within (he casing. However, the manufacture of such perforated pipes is awkward in terms of production techniques. The purpose of this mvention is to piovide a filter with adequate resistance to the pressure within the filter casmg caused by the substance to be filtered, and with lower production costs than conventional filters The filter m accordance with the invention is characterised by the fact that it includes a support member forming a solid extension ofthe collar, and consisting of an axial spmdle inside the filter means and of an end flange at the end opposite to the collar, the periphery of the end flange being tightly sealed to the inner wall of the casmg such that the support member will receive the internal pressuie within the casmg axially In a filter m accordance with the mvention, the axial traction force caused by the pressure is not at all exerted on the casmg, but merely on the spmdle of the support membei and on the end flange, thus allowing a thmner mateπal thickness in the casmg wall If the filter is equipped with a perforated support pipe placed agamst the filter means, this may also be made thmner than before, which is a significant benefit in terms of manufacture techmques Smce the end flange sealed agamst the casmg seals the pressurised casmg inteπoi to be filled with the substance to be filtered, the casmg end does not have to be sealed as in conventional filters, but mstead, the casmg may be formed of a sleeve-like tubular piece which is open at either end In the filter m accordance with the invention, the support member mcludmg the spindle and the collar connecting the filter with the device assembly may be discrete components connected with each other by a threaded joint In this manner, these components are joined by a jomt with high mechanical strength and resistance to the traction force, which also is easy to open with a view to replace the collai. for instance By a snnple replacement of the collar, the filter is adaptable to threads of vaπous sizes provided for the filter in the device assembly The filter m accordance with the mvention preferably includes a joint ring between the openable casmg end and the device assembly, the joint nng mcludmg one or more flow opemngs, through which the casmg mteπoi communicates with one or more inlet ducts for the flow to be filtered m the device assembly In this case, the flow is steered mto the casmg outside the mantle of the cylindrical filter means, from where the flow is filtered mside the mantle, and eventually is removed via the mside of the collar into the outlet duct for filtered flow in the device assembly In tins case the innei surface of the filtei means may bear against the perforated support pipe, which can be advantageosuly manufactured of a thinner mateπal than before, as indicated above The invention will be described in greater detail below by means of examples and with reference to the accomanying drawings, of which figure 1 shows an oil filter with a sleeve-like casing in accordance with the invention, and a device assembly to which the filter can be attached by screwing, figure 2 shows a second oil filter with a sleeve-like casing in accordance with the invention, figure 3 shows a cross-section of the filter along line III-III of figure 1, and figure 4 shows a cross-section of the filter along line IV-IV in figure 1. Figure 1 illustrates a "spin-on filter" 1 in accordance with the invention, which is especially suitable as a replaceable oil filter in a combustion engine. The filter consists of components, which, assembled as in figure 1, can be connected by a threaded joint 2, 3 to device assembly 6 comprising inlet and outlet ducts 4, 5 for the flow to be filtered. The filter in figure 1 comprises a sleeve-like casing 7 appropriately made of metal or plastic, which has a cylindrical, closed mantle 8 and an end 9, and which is open at its opposite end facing the device assembly 6. Inside casing 7 a support member 10 is disposed, which consists of an axial spindle 1 1 with a cross-shaped cross- section, an end flange 13 placed at the spindle end and sealed against the inner surface of the casing mantle 8 with an O-ring joint 12, and of a ring element 14 at the opposite end of the spindle, facing the casing mouth, the support member being attached to the collar 16 attaching the filter to the device assembly 6 by means of the threaded joint 15. The cross-shaped spindle 11 is surrounded by a perforated support pipe 17, which extends from the collar 16 axially to the end flange 13 of the support member. In the space 18 between the support pipe 17 and the casing mantle 8, a cylindrical, replceable filter means 19 has been fitted, whose filtering layer preferably consists of e.g. pleated paper or non-woven fibre pulp. Placed against the open end of the casing 7 is a joint ring 20 between the casing and the device assembly, the joint ring having flow openings 21 to connect the inlet ducts 4 for flow to be filtered in the device assembly with the interior 18 ofthe casing. The joint ring 20 is equipped with an O-ring seal 22 to seal the filter 1, when screwed into position, against the device assembly 6. The sealing between the casing 7 and the joint ring 20 is provided by moulding the outer edge ofthe end flange 23 of the filter means 19 as an O-ring seal 24 placed against the outer surface of the casing mouth. Inside the edge 24 acting as a seal the flange 23 has openings 25 for the incoming flow of substance to be filtered. A filter 1 assembled as in figure 1 is attached to device assembly 6 by screwing the internal thread 2 in collar 16 into the matching extemal thread 3 in the device assembly. With filter 1 in operation, the flow to be filtered is directed from inlet ducts 4 through the joint ring 20 and flow inlets 21, 25 in the end flange 23 of the filter means into a space 18 delimited by casing 7, from where the flow is filtered through the filter material layer in filter means 19 and the perforated support pipe 17 into the space 26 within the pipe, from where the filtered flow is removed into outlet duct 5 in the device assembly through the openings 27 in the end ring 14 of the support member 10 and the collar 16. The flow direction is indicated with arrows in figure 1. A clogged filter means 19 is replaced by screwing off the filter 1 from the device assembly 6, by withdrawing the joint ring 20 from the casing 7 and the collar 16 and by removing the filter means 19 from the space 18 between the casing and the support pipe. After this, a new filter means 19 is fitted into space 18 with the outer edge 24 of its end flange 24 fitted as a seal around the mouth of casing 7, and subsequently the joint ring 20 is pressed into position and the filter thus assembled is fixed to the device assembly 6 by screwing it to the assembly as a unit. The optional embodiment of the invention shown in figure 2 differs from the embodiment of figure 1 in that the casing 7 consists of a cylindrical sleeve, which is tightly sealed at its end opposite to the device assembly by the end flange 13 of the support member 10. In other respects, the presentation above of the design and operation of the filter of figure 1 applies as such to the filter in figure 2. It is obvious to those skilled in the art that the various embodiments ofthe invention are not restricted to the examples given above, but may vary within the scope of the accompanying claims. Thus, the threaded joint between the filter 1 and the device assembly 6 may differ from figures 1 and 2 in that the filter collar 16 is provided with an external thread and the device assembly with a matching internal thread. Besides lubricating oil filters, the filters in accordance with the invention may also serve as hydraulic liquid, liquid fuel or water filters.

Claims: Claims 1. A filter (1) for filtering a flowing substance, such as oil, comprising a casing (7) which is openable at one end, a substantially cylindrical, replaceable filter means (19) fitted inside the casing, the flow to be filtered being arranged to pass through the mantle ofthe filter means, and a collar (16) for connecting the filter with a device assembly (6) including inlet and outlet ducts (4, 5) for the flow to be filtered, characterised in that the filter (1) comprises a support member (10) forming a solid extension of the collar ( 16). and consistmg of an axial spindle ( 11) within the filter means (19) and of an end flange (13) at its end opposite to the collar, the periphery of the end flange being tightly sealed to the inner wall of the casing (7) such that the support member will receive the interior pressure in the casing axially. 2. A filter as claimed in claim 1, characterised in that the support member (10) and the collar ( 16) are discrete components joined by a threaded joint (15). 3. A filter as claimed in claim 1 or 2, characterised in that the collar (16) comprises a thread (2) for connecting it with the device assembly (6). 4. A filter as claimed in any of the preceding claims, characterised in that the spindle (11) of the support member is substantially cross-shaped in cross-section. 5. A filter as claimed in any of the preceding claims, characterised in that the support member ( 10) and the casing (7) are discrete components, sealed against each other with an O-ring seal (12) surrounding the end flange (13) of the support member. 6. A filter as claimed in any of the preceding claims, characterised in that the flow to be filtered is arranged to pass from the outside to the inside of the mantle of the filter means (19), in that the filter can be connected via the inside of the collar (16) with an outlet duct (5) for flow to be filtered in the device assembly (6) and in that the spindle (11) of the support member is surrounded by a perforated pipe (17), which supports the filter means on the inner surface of its mantle. 7. A filter as claimed in any of the preceding claims, characterised in that the casing (7) has the shape of a cylindrical sleeve, which is open at its one end facing the device assembly (6) and sealed at its other end (9). 8 A filter as claimed m any of claims 1 to 6, characterised in that the casmg (7) consists of a cylmdπcal sleeve, which is tightly sealed by the end flange (13) of the support member at its end opposite to the device assembly (6) 9 A filter as claimed m any of the preceding claims, characterised m that the filter comprises a joint rmg (20) between the openable end of the casing (7) and the device assembly (6), the joint img having one or moie openings (21) to allow the casing interior ( 18) to communicate with the inlet duct (4) for flow to be fil t eied the device assembly 10 A filter as claimed in clann 9, characterised m that the seal (24) between the casing (7) mouth and the jomt rmg (20) is located on the outer surface of the casmg mouth

Inventors: KOIVULA TUOMO, KOIVULA, TUOMO
Applicants: KOIVULA TUOMO, PARKER HANNIFINN OY, KOIVULA, TUOMO
Application year: 1996
Main classification: B01D27
IPC codes: B01D27, B01D29, B01D35