GB2122106A

GB2122106A - Water-air separator

Info

Publication number: GB2122106A
Application number: GB08315853A
Authority: GB
Inventors: Robert Steuart Gladstone
Original assignee: Coopers Filters Ltd
Current assignee: Coopers Filters Ltd
Priority date: 1982-06-16
Filing date: 1983-06-09
Publication date: 1984-01-11
Also published as: DE3321688A1; SE8303386L; GB2122105A; ES8404869A1; GB2122106B; IT8348507A0; GB8315853D0; FR2528716B1; ES523329A0; SE8303386D0; FR2528716A1

Abstract

Water droplets are separated from air being fed to an I.C. engine by causing the air to change direction, in passage from inlet 7 to outlet 6, adjacent to a wire mesh pad 9 backed by impervious wall 8, so that the droplets impinge on and penetrate the pad and flow down it to outlet 11. <IMAGE>

Description

1 GB 2 122 106 A 1

SPECIFICATION Improvements in and relating to air cleaners

This invention relates to air cleaners and in particular to apparatus for at least reducing the amount of liquid entrained in an airstream ei.itering an air cleaner. Where a conventional air Odaner is used to filter the airflow to an internal combustion e.ngine; it is often important to remove entrained -liquid, or to at least reduce it to an acceptable level. Paper air filters are not well suited to handling mixed liquid air flows. Water vapour it fairly well tolerated and may improve combustion efficiency. On the other ha nd, the levels of entrained liquid are often extremely high in the vicinity of road vehicles travelling at speed in wet weather.

Known liquid separators make use of centrifugal force and/or a sudden change of airstream direction which causes the heavier water particles/droplets to become ballistically separated from the airstream onto some form of collector surface which is connected to a drain aperture or channel. These known separators are not particularly efficient and it has been proposed that the airstream should be passe d through a coarse wire mesh. The latter is known for its ability to coalesce droplets of liquid from an airstream, but where the throughput of wet air is high, the mesh may become "plugged" releasing quantities of water in the downstream direction. At low 95 temperatures the mesh may also ice up.

According to the present invention, apparatus for separating entrained liquid droplets from a gas flow comprises a casing containing a generally vertically disposed collector means in the form of a foraminous reticulated structure having a lower edge portion which abuts in sealing relation to a generally vertical wall portion of the casing, said wall portion having an inlet in the form of a generally horizontally extending slot, the 105 horizontal margins of which are shaped to accelerate the inlet gas flow towards the collector means so that the gas flow is constrained to undergo a change of direction of at least 901 prior to travelling generally upwardly over the collector 110 means and thereafter to an outlet from the casing.

Preferably also, the liquid collector is so disposed as to be self-draining, liquid outlet means being provided for removing collected liquid to the outside of the casing.

Where the inlet communicates directly with a 115 liquid-laden gaseous atmosphere, it is preferred that the margins of the inlet are shaped to deflect and/or exclude liquid which may collect on the external or internal surface of the casing. In particular, it is important to minimise the amount 120 of such liquid which becomes entrained by the gas flow into the inlet.

As previously stated, it is advantageous to make the liquid collector means self-draining, under gravity. It is also convenient to make the gas 125 flow generally upwardly over the liquid collector, i.e. against gravity, to enhance the separation effect.

In order that the invention be better understood preferred embodiments of it will now be described with reference to the accompanying drawing in which:

Figure 1 is a cross-sectional side view of a liquid separator according to the invention, and Figure 2 is a cross-sectional side view of a modified liquid separator according to the invention.

In the figures, a casing 5 has an outlet 6 and a slot inlet 7. A liquid collector comprising an' impermeable support 8 and a layer of steel wire mesh 9 is mounted inside the casing so that.gas entering through the slot 7 has to undergo an abrupt, change of direction from slightly - downwards (relative to the top of the casing) to a vertical or near vertical path along the surface of the mesh 9, before passing around the end of an impermeable retaining cap 4, towards the outlet. The cap 4 serves to minimise re-entrainment of liquid collected on the mesh, whilst an outlet 11 serves to drain the latter. In Figure 2 collector tubes 11 serve to accomplish this function, to the sides of the casing.

The slot has an upper lip in the form of an external channel 3 disposed to prevent liquid dripping directly into the inlet. The lip also has an internal channel 13 to serve the same purpose internally of the casing. The opposed edge 14 of the slot is also rounded, to smooth the inlet gas flow. It will be appreciated that Figure 2 features two slots and two liquid collectors, as well as a differently directed outlet. Two slots enable a greater throughput. 100 in one practical embodiment based on Figure 1, the casing was generally rectangular with a slot dimension 2 in the range 20 to 30 mm, the exact size being selected so that for a given slot width, the peak flow velocity into the casing was about 20 m/s. The dimension 1 was about 40 mm, the wire mesh 9 being about 12 mm thick. The separator exhibited an overall pressure drop (from inlet to outlet) of about 55 mm of water. On test with air artificially loaded with large quantities of water (by spraying), the separator removed about 85% of the water supplied to it. It was extremely effective.

Claims

1. Apparatus for separating entrained liquid droplets from a gas flow, characterised in that the apparatus comprises a casing containing a generally vertically disposed collector means in the form of a foraminous reticulated structure having a lower edge portion which abuts in sealing relation to a generally vertical wall portion of the casing, said wall portion having an inlet in the form of a generally horizontally extending slot, the horizontal margins of which are shaped to accelerate the inlet gas flow towards the collector means so that the gas flow is constrained to undergo a change of direction of at least 900 prior to travelling generally upwardly over the collector means and thereafter to an outlet from the casing.

2 GB 2 122 106 A 2 2. Apparatus according to claim 1 characterised by the provision of a liquid outlet from the casing at the junction between the 15 collector means and the casing wall, whereby the collector means is self- draining.

3. Apparatus according to claim 1 -or claim 2, characterised in that the outlet gas flow is generally horizontal, following a substantially 900 change of direction around an upper margin of the 10 collectormeans.

4. Apparatus according to claim 1 or claim 2,. characterised in that the outlet gas flow is generally vertically downwards following a substantially 1801 change of direction around an upper margin of the collector means.

5. Apparatus according to any preceding claim further characterised in that the margins of the inlet are shaped to deflect and/or exclude liquid which in use may collect on the internal and/or 20 external surfaces of the casing.

6. Apparatus for separating entrained liquid droplets from a gas flOw substantially as described with reference to and as illustrated by the accompanying drawing.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1984. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.