GB1591513A

GB1591513A - Cleaner for pressurised gas

Info

Publication number: GB1591513A
Application number: GB41709/77A
Authority: GB
Original assignee: KNORR BREMSE GmbH; Daimler Benz AG; Knorr Bremse AG
Current assignee: KNORR BREMSE GmbH; Daimler Benz AG; Knorr Bremse AG
Priority date: 1976-10-13
Filing date: 1977-10-06
Publication date: 1981-06-24
Also published as: DE2646259B2; FR2367523A1; DE2646259A1; IT1112067B; DE2646259C3

Description

(54) A CLEANER FOR PRESSURISED GAS (71) We, KNORR-BREMSE GmbH., Moosacher Strasse 80, D-8000 Munchen 40 and DAIMLER-BENZ AG., Postfach 202, D-7000 Stuttgart 60, Federal Republic of Germany, and both German companies, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a cleaner for a pressurised gas, and is particularly but not exclusively concerned with a compressed air cleaner which may be used in compressed air operated braking installations of motor vehicles.

According to the invention there is provided a cleaner for a pressurised gas comprising: a filter casing having an inlet and an outlet arranged at one end of the casing, and a condensate outlet arranged at the opposite end of the casing; a hollow member arranged in the casing to define a chamber which communicates with said inlet and which extends between the outer surface of said member and the inner surface of said casing; a filter arranged in said chamber to define a gas-cleaning path extending in a direction from said one end of the casing towards said opposite end of the casing; means connecting said gas-cleaning path to the interior of the hollow member; an outlet leading into the interior of the hollow member and communicable with the outlet of the filter casing; a valve seat provided about the outlet of said filter casing; and means biasing the hollow member into contact with said valve seat so that the outlet of the hollow member communicates with the outlet of the filter casing, the hollow member being movable in use against the action of the biasing means, under the action of a predetermined excessive pressure build-up upstream of the filter, out of contact with the valve seat so that uncleaned pressurised gas entering the inlet of the filter casing is able to pass directly to the outlet of the filter casing without passing through the filter.

Preferably the hollow member is, by stops provided by the filter casing, displaceable only for a pre-determined distance.

Embodiments of cleaner for a pressurised gas according to the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-section of a compressed air cleaner; and Figure 2 is a plan view of an alternative construction of base for a hollow member of the cleaner.

The cleaner which will be described is intended primarily for cleaning compressed air e.g. compressed air used to operate a brake system. However, it should be appreciated that the cleaner may be used to clean gases other than compressed air if desired.

The pressure air cleaner comprises, referring to Figure 1, a filter casing in the form of a can 1 which is sealed air-tight with a cover 2. Arranged centrally in the cover 2 is an aperture 4 from which a collar extends into the filter can, the lower edge thereof being designed as a valve seat 6. The aperture 4 may be provided for example with an internal screwthread into which an outlet port stub 8 (shown in dot-dash line) is screwed in. Formed adjacent to the aperture 4 is a further aperture 10 in the cover, which in the case of the example of embodiment shown is designed as a blind aperture out of which lateral slots 12 extend into the chamber under the cover 2. The aperture 10 can, in the same manner as aperture 4, be provided with an internal screwthread into which an inlet port stub 14 shown in dotdash line is screwed in.

Arranged coaxially to the filter can 1, in the latter, is a hollow member partly closed at each end to form an inner vessel 16. The external diameter of the vessel 16 is smaller than the clear internal diameter of the filter can 1, so that there is formed between the vessel 16 and the filter can 1 an annular chamber which is completely filled by a fil ter cartridge 18, preferably in the form of a knitted metal structure or gauze.

The upper end of the vessel 16 is slightly curved outwardly and is so designed that it is able to make an abutment at the valve seat 6. Within the contacting line of the upper end of the vessel 16 with the valve seat 8, in the vessel 16, is an outlet comprising an aperture 20 which communicates with the interior of vessel 16. Between the cover 2 and the top surface of the vessel 16 there remains free a chamber 22 serving for uniform distribution of the pressure air flowing in through the slots 12. The vessel 16 is assembled from an upper, bell-like element 16', and an inverted base 28 latched therein.

The base 28 has an impervious face 28' descending towards its edge and from the edge of which there project upwardly projections 29 which are uniformly distributed about the periphery and are arranged in spaced relationship relative to each other.

The projections 29 carry flanges 29' engaging under the lower edge of the element 16' and are engaged with their upper edges, by means of latching ends 29" into the element 16'.

In the lower zone of the cylindrical wall of the vessel 16, there are formed radial passages 24, due to the interspaces between the projections 29, which said passages provide means conducting pressure air, after flowing through the metal gauze 18, to the interior of the vessel 16.

The vessel 16 may be made from an optional material, but preferably from plastics material, and provided internally in the zone of the element 16' with reinforcing ribs 26 and also at the base with reinforcing ribs 26' supporting the projections 29 thereof.

The base 28 is loaded from below by a spiral compression spring 30 bearing also on the base of the filter can 1, the spring 30 comprising biasing means for biasing the vessel 16 into contact with valve seat 6 and so as to intercommunicate the apertures 20 and 4. Due to the force of the spring 30, the entire inner vessel 16 is pushed upwardly, so that its upper end makes an abutment with the valve seat 6 and shuts off the chamber 22 from the outlet port stub 8 or the outlet aperture 4. The only possible path for the pressure air leads, with disposition of the inner vessel 16, through the filter cartridge 18 and the radial passages 24 into the interior of the vessel 16 and from there through the apertures 20 and 4 into the outlet port stub 8. Formed in the base of the filter can 1 is an outlet aperture 32 into which a dehydrating or liquid drain valve 34 (shown in dot-dash line) is screwed in.

The mode of operation of the pressure air cleaner is as follows: The pressure air flowing-in through the inlet port stub 14 is distributed uniformly in the chamber 22 by means of the slots 12 and penetrates from above in the axial direction into the filter cartridge 18 in the form of a metal gauze. The pressure air flows axially through the entire length of the filter cartridge and is, due to the long filter path, well cleaned. Simultaneously, the condensate available in small droplets in the pressure air is separated from the pressure air. The pressure air is also well cooled, so that intensive condensate precipitation takes place. The heat is transimitted from the metal gauze of the filter cartridge directly to the outer wall of the filter can 1 and therewith rapidly to the atmosphere. Due to gravity, the water flows out of the filter cartridge downwardly, accumulates in the base of the filter can 1 and is precipitated to the atmosphere via the valve 4. Due to the shape of the base face 28', the air is compelled to flow through the apertures 24 and is not able to entrain with it into the vessel 16 any water which has accumulated at the lower element or portion of the filter can.

If, then, due to a soiled filter cartridge 18, the throughflow resistance of the filter cartridge increases and therewith also the pressure in the chamber 22, which may also be the case in the event of low external temperatures, when the water contained in the filter cartridge freezes, a corresponding pressure is exerted on the upper end of the vessel i.e. upstream of the filter. Since the face subjected to pressure is extremely large, even a slight degree of positive pressure of approximately 0.5 bar on the upper end of the vessel 16 is sufficient to press the latter downwardly against the force of the compression spring 30. Thereby, the inlet port stub 14 and the outlet port stub 8 are short-circuited when a predetermined excessive pressure build-up develops upstream of the filter (as can quite readily be ascertained from the drawings) and therewith optionally further supply to a pressure air consumer is guaranteed.

Thus, the pressure air cleaner described above has an excellent degree of filtering efficiency, since the filter cartridge does not require to have a radial throughflow, but an axial throughflow, whereby at the same time good cooling and therewith condensate precipitation results. Furthermore, even in the event of slight flow resistance of the filter, the latter is by-passed, so that no significant pressure loss can occur which would be extremely undesirable at the delivery end of the cleaner.

It is possible to provide the filter can 1 externally with cooling ribs.

Referring to Figure 2, an alternative construction of base for vessel 16 is illustrated.

After omitting the reinforcing ribs 26', it is possible to provide the base 28 with air guiding webs 36 which are disposed on the base face 28' and lead spirally inwardly from the projections 29. These air guiding webs 36 impart to the air, flowing-in through the apertures 24 into the vessel 16, a twist due to which residual condensate is hurled by centrifugal effect against the inner wall of the element 16' and from there is able to flow-away downwardly.

WHAT WE CLAIM IS: 1. A cleaner for a pressurised gas comprising: a filter casing having an inlet and an outlet arranged at one end of the casing, and a condensate outlet arranged at the opposite end of the casing, and a condensate outlet arranged at the opposite end of the casing; a hollow member arranged in the casing to define a chamber which communicates with said inlet and which extends between the outer surface of said member and the inner surface of said casing; a filter arranged in said chamber to define a gas-cleaning path extending in a direction from said one end of the casing towards said opposite end of the casing; means connecting said gas-cleaning path to the interior of the hollow member; an outlet leading into the interior of the hollow member and communicable with the outlet of the filter casing; a valve seat provided about the outlet of said filter casting; and means biasing the hollow member into contact with said valve seat so that the outlet of the hollow member communicates with the outlet of the filter casing, the hollow member being movable in use against the action of the biasing means, under the action of a predetermined excessive pressure build-up upstream of the filter, out of contact with the valve seat so that uncleaned pressurised gas entering the inlet of the filter casing is able to pass directly to the outlet of the filter casing without passing through the filter.

2. A cleaner according to claim 1, in which said connecting means comprises passages provided at or near the end of the hollow member adjacent said opposite end of the filter casing.

3. A cleaner according to claim 2, in which the biasing means comprises a spring engaging with said end of the hollow member.

4. A cleaner according to any one of the preceding claims, in which the filter casing and the hollow member are arranged cylindrically and co-axially in relation to each other.

5. A cleaner according to any one of the preceding claims, in which the outlet of the filter casing is arranged centrally in said one end of the filter casting, and an annular chamber surrounds the valve seat and communicates with the upstream end of the filter and with the inlet of the casing.

6. A cleaner according to any one of the preceding claims, in which the inlet of the casing via a plurality of slots extending transversely of the general direction of flow of gas through the inlet.

7. A cleaner according to claim 2 or any one of claims 3 to 6 when appendant to claim 2, in which the hollow member comprises a bell-like element and an inserted base latched thereto, said base having an impervious face which extends downwardly from its central position towards its peripheral edge (in the usual position of use of the cleaner) and projections arranged uniformally distributed along said edge and in spaced relationship relative to each other so as to define said passages, said projections being latched into engagement with the edge of the bell-like element remote from the inlet of the casing.

8. A cleaner according to claim 7, in which the hollow member is made of plastics material, and said projections and said belllike element are reinforced by ribs.

9. A cleaner according to claim 7, in which the hollow member is made of plastics material, and the base carries on its face gas-guiding webs extending spirally from the projections.

10. A cleaner according to any one of the preceding claims, in which the filter comprises a cartridge made from a metal gauze.

11. A cleaner according to any one of the preceding claims, in which the filter casing is intended in use to have its axis extending vertically, and is provided at said opposite end thereof with a liquid drain valve forming said condensate outlet.

12. A cleaner according to any one of the preceding claims, in which the hollow member is displaceable relative to the filter casing between limit stops provided by the filter casing.

13. A cleaner according to claim 1 and substantially as hereinbefore described with reference to, and as shown in Figure 1 or Figure 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. face 28' and lead spirally inwardly from the projections 29. These air guiding webs 36 impart to the air, flowing-in through the apertures 24 into the vessel 16, a twist due to which residual condensate is hurled by centrifugal effect against the inner wall of the element 16' and from there is able to flow-away downwardly. WHAT WE CLAIM IS:

1. A cleaner for a pressurised gas comprising: a filter casing having an inlet and an outlet arranged at one end of the casing, and a condensate outlet arranged at the opposite end of the casing, and a condensate outlet arranged at the opposite end of the casing; a hollow member arranged in the casing to define a chamber which communicates with said inlet and which extends between the outer surface of said member and the inner surface of said casing; a filter arranged in said chamber to define a gas-cleaning path extending in a direction from said one end of the casing towards said opposite end of the casing; means connecting said gas-cleaning path to the interior of the hollow member; an outlet leading into the interior of the hollow member and communicable with the outlet of the filter casing; a valve seat provided about the outlet of said filter casting; and means biasing the hollow member into contact with said valve seat so that the outlet of the hollow member communicates with the outlet of the filter casing, the hollow member being movable in use against the action of the biasing means, under the action of a predetermined excessive pressure build-up upstream of the filter, out of contact with the valve seat so that uncleaned pressurised gas entering the inlet of the filter casing is able to pass directly to the outlet of the filter casing without passing through the filter.