Background art

In prior known filters of the above-discussed type, the filter element is sealed on the nipple with a conventional O-ring seal. For example, the publication US 6,099,726 discloses such a filter. There, the nipple is positioned at the bottom end of the filter chamber and the filter element has its bottom cap provided with a tube placing itself on the outer surface of the nipple. The tube has on its inner surface a circular slot with an O-ring seal therein. General description of the invention

What is sought to be protected by a patent is presented in the claims.

In a filter according to the invention, the filter element is sealed against a nipple with a ring seal, whereby either the normal to the plane of the ring seal forms an acute angle with the axis of the element or the normal to the plane defined by the end of the response element not provided with a ring seal, forms an acute angle with the axis of the element. The angle is preferably 1 - 60 °, more preferably 5 - 45 °, most preferably 10 - 20°. As a result, the force required for inserting the ele- ment in place is smaller than that required when using conventional O-ring sealing. The element can be set in place by a smooth sliding action, and no powerful sudden motion is needed. Neither does the seal disengage from its slot in the element insertion process as easily as when using a conventional sealing arrangement. Respectively, the withdrawal of the element is also easier. The invention enables the use of a tighter and thereby also a more secure sealing.

Most favorably, it is the normal to the ring seal that forms the acute angle with the axis of the element.

The nipple is a cylindrical tube in the filter chamber. Most preferably, it extends into the interior of the chamber. The filter element has an end cap, which is provided with a cylindrical response tube to be sealed on the nipple. Most preferably, the response tube is made in one piece with the end cap. Most preferably, the response tube is received on the outer surface of the nipple. Most preferably, the seal in this case lies in a slot present on a surface of the complementary tube. Alternatively, the complementary tube may be accommodated on the inner surface of the nipple. In this case, as well, the seal lies most preferably in a slot present on the surface of the response tube.

Most preferably, the filter chamber has an openable lid for replacing the filter elements thereby. The filtering surface of the filter element may especially consist of a pleated filter fabric. The element has a support member in the form of a perforated pipe with a top cap at its upper end and a bottom cap at its lower end.

There may even be several filter elements and respectively nipples in the filter chamber.

At the end of the filter element opposite with respect to the nipple, the inlet and outlet sides may also be separated from each other with an inclined ring sealing similar to that at the end with the nipple.

Most preferably, the fluid to be filtered is passed through the filtering surface from outside to inside, the filtered fluid being discharged through the nipple. The filter can be used for filtering both liquids and gases. The liquid to be filtered may be e.g. a lubricating liquid, a liquid fuel, a hydraulic liquid, or water.

Drawings

The accompanying drawings constitute a part of the written description of the invention and are related to the detailed description of some embodiments of the invention. In the drawings, fig. 1 shows a filter in cross-section, fig. 2 shows in an enlarged view the detail B of fig. 1 at th bottom end of the e filter, and fig. 3 shows in an enlarged view the detail C of fig. 1 at the top end of the filter.

Detailed description of some embodiments of the invention

The filter according to the drawings comprises a cylindrical filter element 2, dis- posed longitudinally in a filter chamber 1 having the shape of a circular cylinder. At the bottom 3 of the chamber there is a hole, which is in line with the element and fitted with a tubular nipple 4 for placing the element thereon. The top end of the chamber is closed with an openable lid 5. At the side of the chamber there is an inlet fitting 6 for a fluid to be filtered. Under the chamber bottom there is a filtered flu- id receiver 7 provided with an outlet fitting 8 for the filtered fluid. The receiver has its bottom provided with a receiver drain fitting 9, and the filter chamber has its lower part provided with a filter chamber drain fitting 10.

The filter element 2 has on its inside a perforated support pipe 1 1 , having dis- posed on its outer surface a pleated filter fabric 12. At the bottom end, the filter fabric is held stationary by a bottom cap 13 and at the top end by a top cap 14. The lower end of the bottom cap constitutes a cylindrical response tube 15 received against the outer surface of the nipple 4. The response tube has its inner surface formed with a circling annular slot 16 such that the normal thereto is at an angle of 10 - 20 ° relative to the axis of the element. In the slot there is fitted a ring seal 17.

The filter has inside its lid 5 a cylindrical sleeve bracket 18 in register with the filter element 2. Between the sleeve bracket and the upper surface 19 of the top cap 14 there is in the normal situation a small gap. The sleeve bracket prevents the filter element from rising off the nipple.

The filter element 2 has its top cap 14 provided with a tubular upright 19 having an O-ring seal 21 in a slot on its inner surface. The support pipe 1 1 of the element has an extension in the form of a cylindrical lip 22 having a closed upper end. The lip has its outer surface functioning as a seating surface for the seal. The top cap is further provided with a pivoting handle 23 for lifting and lowering the element.