LIQUID SEPARATOR AND FILTER ELEMENT THEREFOR
The present invention concerns a liquid separator containing a housing which is provided with an inlet and an outlet and which consists of a vessel and a lid closing off the lid, and a filter element provided with an outwardly protruding collar with which it is fixed to the housing and whereby, between this filter element and the housing, are provided at least two seals.
Such liquid separators are used among others in liquid- lubricated rotating compressors, in particular screw-type compressors, in particular oil-lubricated compressors, i.e. in which the liquid is oil-
In such known liquid separators, the collar of the filter element is a flat, round flange, whereas the seal is realized in the shape of two sealing rings which are provided in the lid and in an outwardly directed edge of the vessel respectively.
However, the presence of the filter element is hard to establish visually.
Hence, during the assembly in the workshop, the filter element is sometimes omitted, which may have serious results for the machine or the compressor.
As long as no pressure drop is measured in the filter element, its absence will not even be noticed during the testing if the sealing rings have been provided, which
may for example be the case if they have been pre- assembled in the lid or the vessel. As a result, there will be no leak during the testing which can be noticed.
The present invention aims a liquid separator which excludes these and other disadvantages and whereby the possible absence of the filter element can thus be easily noticed.
This aim is reached according to the present invention in that two seals have been provided in a groove in the filter element, one of which has been provided in a groove in the collar and fitting up to the vessel, whereas the other fits up to the lid, so that the part of the filter element containing the grooves with the seals provides for the seal between the vessel and the lid.
As the seals have been provided in grooves of the filter element, there will be no seal between the vessel and the lid when said filter element has not been provided, and there will be an audible and/or visible leak between the vessel and the lid when the housing is put under pressure during the testing. Usually, it is still possible then to insert a filter element.
If the filter element has been provided, the sealings will be pressed against the vessel, against the vessel and the lid respectively, as a result of the weight of the lid or the mechanical pulling of the lid, and thus provide for a sealing between the vessel and the lid.
Preferably, the vessel has a strip on the inside and next to the edge with which it is situated against the lid, which is directed towards said lid in a slanting manner
and inclined towards the outside in the direction of the lid, and the seal which has been provided in the groove in the collar fits up to this slanting strip.
Thanks to the slanting strip, when the liquid separator is put under pressure and the liquid flows in the direction of the lid, as a result of the pressure difference over the filter element, the collar and thus the above-mentioned seal will be pressed more strongly against the slanting strip. The extra force on the seal in the collar or flange against the slanting strip which widens towards the outside is obtained thanks to a slight deformation of the collar towards the outside under the influence of the radial pressure. This requires appropriate dimensions and an appropriate choice of material for the collar.
Preferably, also the side of the lid directed towards the filter element is provided with a slanting strip, and the seal which fits up to the lid is situated against this slanting strip.
Towards the middle of the lid, this slanting strip may either move away from the inside of the vessel or approach this inside.
On the side of the lid, the filter element may be provided with a preferably ring-shaped head with an integrated collar, whereby the grooves with the seals are provided in this head, for example near the outer edge of the collar and there where the collar fits up to the rest respectively .
The seals may be elastic rings, for example 0-rings.
The filter element can be surrounded by a shield, in which case this shield can be provided with an outward directed collar which is situated between a part, for example a shoulder of the vessel and the head of the filter element.
In order to better explain the characteristics of the invention, the following preferred embodiment of a liquid separator and of a filter element therefore is described as an example only and without being limitative in any way, with reference to the accompanying drawings, in which:
figure 1 schematically represents a section of a liquid separator according to the invention; figure 2 shows a section according to line II-II in figure 1, to a larger scale; figure 3 shows the detail which is indicated by F3 in figure 2 to a still larger scale; figure 4 represents a detail analogous to that in figure 3, but with reference to another embodiment of the invention,; figure 5 represents a detail analogous to that in figures 3 and 4, but with reference to yet another embodiment of the invention.
The liquid separator according to the invention which is represented in figures 1 to 3 mainly consists of a housing 1 which is composed of a round vessel 2 and a lid 3, and a filter element 4 fixed in this vessel 2 against the lid 3.
The vessel 2 is provided with an inlet 5 for a mixture of compressed air and liquid, for example oil, whereas the
lid 3 is provided with an outlet 6 in the middle for the air which has been purified from the liquid.
The lid 3 is secured to the vessel 2 by means of screws 7 which protrude through openings 8 in the lid 3 and which are screwed in openings 9 which are screwed in an end 10 or collar of the vessel 2 which is thickened towards the end .
The lid 3 is provided with a ring-shaped collar 11 on the inside, right next to the farthest edge on said thickened end 10, to position the lid 3 on the vessel 2.
Next to the farthest edge and this collar 11, the inside of the thickened end 10 has a ring-shaped part 12 all around. This part 12 is preferably slanted, as in the given example, namely widening towards the lid 3 and thus directed slantingly towards the outside, at an angle a in relation to the longitudinal direction, i.e. in the direction of the longitudinal axis 13 of the housing 1 of the liquid separator. This angle a can be situated between 1° and 89°, but is preferably situated between
10° and 80° and is for example almost equal to 45° or, as is represented, about 30°.
A small strip 14 of this slanting part 12 has been mechanically processed.
Right next to said strip 14 on the side turned away from the lid 3, the inside of the vessel 2 has a shoulder 15 projecting towards the inside.
Also the inside of the lid 3 is provided with a ring- shaped part 16 around the outlet 6, a small strip 17 of
which has been mechanically processed. This part 16, and thus also the strip 17 thereof, are preferably positioned slantingly in relation to the longitudinal axis 13, as in the given example .
This slanting part 16 is directed away from the collar 11 and thus towards the outlet 6 or towards the middle of the lid 3, moving away from the inside of the vessel 2, and it has a slope or angle β in relation to the longitudinal axis 13 which is situated between 1° and 89° and preferably between 45° and 89°, for example between 60° and 85° .
The filter element 4 mainly consists of a ring-shaped head 18 and a filter part which itself consists of filter material 19 which is surrounded by a housing 20 with two concentric, perforated walls 21 and 22. 2. At the end moved away from the lid 3 , the filter element 4 is sealed by a bottom 23.
This bottom 23 is provided with a bulge in which opens an exhaust pipe 24.
The head 18 is made of aluminium or high-grade plastic by means of die-casting, injection-moulding respectively, and it consists of a part 25 forming an inverse gutter and meshing over the end of the filter part 19-20, and an outwardly protruding collar 26.
The filter part 19-20 is cast to the part 25 by means of thermosetting material or another hardening jointing material.
As is represented in detail in figure 3, this part 25 has
an edge 27 against the collar 26, opposite the strip 17 of the lid 3, protruding towards this strip 17 and bevelled accordingly, provided with a ring-shaped groove 28 in which has been provided an elastic sealing ring 29, for example an O-ring.
The free edge of the collar 26 is bent away from the lid 3 and is situated opposite the strip 14 of the vessel 2. The farthest edge of this collar 26 has been bevelled in accordance with the strip 14 and is provided with a ring- shaped groove 30 in which has been provided an elastic sealing ring 31, for example an O-ring.
The filter element 4, in particular the filter part 19- 20, is surrounded by a shield 32. This shield 32 is provided with an outwardly directed collar with which it rests on the shoulder 15 of the vessel 2, and thus is situated between said shoulder 15 and the collar 26 of the head 18.
In order to mount the filter element 4 in the liquid separator, the shield 32 is first placed in the vessel 2 when it is detached from the lid 3, with its collar on the shoulder 15. Then, the filter element 4 is placed with the collar 26 of its head 18 against the strip 14 of the vessel 2.
This vessel 2 is then fixed to the lid 3 by means of the screws 7.
As a result, the sealing ring 29 is pressed against the strip 17 of the lid 3, and the sealing ring 31 against the strip 14 of the vessel 2, such that the head 18 provides for the sealing between the lid 3 and the vessel
2 .
The shoulder 15 forms a support for the shield 32 and a stop which, through the agency of the collar of the shield 32, prevents the farthest edge of the collar 26 from shifting off the strip 14.
Compressed air to be purified which is mixed with oil flows in the vessel 2 via the inlet 5 and subsequently through the filter element 4.
The purified air leaves the liquid separator via the outlet 6.
As a result of the pressure drop in the filter element 4, the pressure on the outside of the filter element 4 is larger than on the inside thereof, so that the head 18 is pressed with even more force against the lid 3 and the vessel 2.
If, for any reason whatsoever, the filter element 4 is not present, there will be no sealing whatsoever between the vessel 2 and the lid 3, and during the testing or during the operation, there will be a clearly visible or audible leak between said vessel 2 and said lid 3.
The embodiment of the liquid separator as represented in figure 4 mainly differs from the above-described embodiment in that the head 18 of the filter element 4, the thickened end 10 of the vessel 2 and of the inside of the lid 3 have another shape.
In particular, the part 12 and thus the strip 14 of the end 10 form a larger angle with the longitudinal axis
13 or an axis parallel thereto, for example of about 45°, and the part 16 and thus the strip 17, towards the middle of the lid 3 towards the inside of the vessel 2, are inclined at an angle β in relation to the longitudinal axis 13 or an axis parallel thereto which is preferably smaller, for example between 30° and 60°.
The part 16 can even be parallel to the part 12, as represented in figure 4 , so that the angles c- and β are equal.
Moreover, there is no collar 11, so that the presence of the head 18 can be visually established through the gap 33 between the end 10 and the lid 3.
The filter element 4 is assembled in the same manner as described above. Also in this embodiment, the slopes of the parts 12 and 16 provide for a solid and leakage-proof sealing thanks to the sealing rings 29 and 31 in the grooves 28 and 30, especially when the filter element 4 is used when there is pressure in the vessel 2.
The embodiment according to figure 5 mainly differs from the embodiment according to figure 4 in that the head 18 of the filter element 4 and the lid 3 have yet another shape.
In particular, the part 16 of the lid 3 and the strip 17 against which the sealing ring 29 fits up are not directed slantingly in relation to the longitudinal axis 13 of the housing 1, but they are perpendicular to it. Further, the edge 27 of the collar 26 of the head 18 of the filter element 4 is not inclined, but also perpendicular to the longitudinal axis 13.
10
Only the part 12 of the thickened end 10 of the vessel 2 and the edge of the collar 26 situated against it are inclined, for example at about 45°, in relation to the longitudinal axis 13, as in the embodiment according to figure 4.
In this embodiment also, the filter element 4 can be clamped with its collar 26 between the lid 3 and the thickened end 10 of the vessel 2 as described above, whereby the sealing rings 29 and 31 provide for a good sealing .
The invention is by no means restricted to the embodiments described above and represented in the accompanying drawings; on the contrary, such a liquid separator and its filter element can be made in all sorts of variants while still remaining within the scope of the invention.