FR2528716A1 - IMPROVEMENTS ON AIR FILTERS - Google Patents

Abstract

THE DROPLET OF LIQUID FROM A GAS CURRENT IS SEPARATED BY BALLISTIC EFFECT BY MAKING THE CURRENT SUBJECT A CHANGE OF DIRECTION SUCH THAT THE DROPS ARE COLLECTED ON A MESHED COLLECTOR STRUCTURE 9.

Description

The present invention relates to air filters and in particular to

  devices adapted at least to reduce the quantity of liquid entrained in a penetrating air stream

  in an air filter When using a covered air filter

  rant to filter the air arriving at an internal combustion engine, it is often important to eliminate the entrained liquid, or at least to bring it to an acceptable level Paper air filters are not suitable for treating currents mixed liquid-air Water vapor is fairly well tolerated and can even improve combustion efficiency In addition, liquid entrainment rates are often extremely high in the vicinity of road vehicles traveling at high speed

speed in wet weather.

  Known liquid temperatures use force

  centrifugal and / or a sudden change in direction of the

  rant of air which brings particles by ballistic effect or

  heaviest water droplets to settle, separating

  rant of the air current, on some form of collecting surface

  this connected to an opening or to a drip channel These known separators are not particularly effective and it has been proposed to pass through a stream of wire mesh with large meshes This is known for its ability to cause coalescence of liquid droplets

  taken from an air stream, but when the air flow

  mide is important, the canvas can be "saturated", released

  down a certain amount of water At low temperatures

  erasing, the canvas can also become frosted.

  According to the present invention, a device specific to

  separate droplets of liquid from a gas stream

  streaks comprises an envelope containing a collecting means disposed in the assembly vertically, formed of an openwork mesh structure of which the lower marginal part abuts in sealing manner against a wall part in the vertical assembly of the envelope, this wall part having an inlet formed by a slot in the horizontal assembly, the horizontal edges of which are in the shape desired to accelerate the gas stream entering towards the collecting means so that the gas stream necessarily undergoes a change of direction of at least 90 before generally sweep up the royen collector and reach the exit of the envelope. Preferably also, the liquid collector is arranged

  so as to undergo a self-draining, a liquid outlet means

  which is provided for discharging the collected liquid outside

laughing envelope.

  When the entry communicates directly with a gaseous atmosphere charged with liquid, it is preferable that the edges of the entry have the desired shape to deflect and / or exclude the

  any liquid collected on the external surface or

  dull envelope especially it is important to minimize

  the quantity of such liquid which is entrained by the cou-

gaseous rant in the entrance.

  As previously stated, it is advantageous to do

  so that the liquid collecting means undergoes a self-

  draining, by gravity It is also advantageous to bring the

  gas stream sweeping the liquid collector in the

  seems from bottom to top, that is to say against the weight-

  to accuse the separation effect.

  To better understand the invention, we will now describe two embodiments with reference to the accompanying drawing, in which:

  Figure 1 is a side sectional view of a separa-

  liquid content according to the invention, and

  Figure 2 is a side sectional view of a varian-

  te of liquid separator according to the invention.

  In the figures, we see an envelope 5 having an outlet 6 and an inlet slot 7 A liquid collector, constituted by an impermeable support 8 and by a layer of steel wire 9, is mounted inside the envelope so that gas entering through slot 7 has to undergo a sudden change of direction to pass from a slightly inclined downward path (relative to the top of the envelope) to a vertical or almost vertical path along the surface of the fabric 9, before going around, towards the exit, the end

  a waterproof retaining cap 4 The cap 4 is used to

  limit the re-entrainment of liquid collected on the fabric, which is evacuated by an outlet 11 In FIG. 2, the same function is assumed by collecting tubes 12, placed on

the sides of the envelope.

  The slot 7 has an upper lip which defines an external channel 3 arranged so as to prevent the liquid from dripping directly into the inlet The lip also defines an internal channel 13 playing the same role inside the envelope The opposite edge 14 of the slot is also rounded

  to regulate the flow of incoming gas.

  It can be seen that, in FIG. 2, two slots are provided

  and two liquid collectors, as well as an outlet

  different tation With two slots, the flow can be higher. In a concrete embodiment based on Figure 1, the envelope was of generally rectangular shape, the dimension 2 of the slot 7 being from 20 to 30 mm, the exact value being chosen according to the width of the slot, and the top speed of penetration into the envelope was approximately 20 m / s The dimension l being approximately 40 mm, the wire mesh 9 being approximately 12 mm thick The overall pressure drop at the

  crossing the separator (from entry to exit) was

  about 54 f O Pa (corresponding to a 55 mm water column).

  When tested with artificially charged air (by spraying) large amounts of water, the separator

  proved to retain about 85% of the water reaching it, which

  has excellent efficiency.

Claims (4)

  1 Device capable of separating entrained droplets of liquid from a gas stream, characterized in that it comprises an envelope (5) containing a collecting means (9) arranged generally vertically, formed of an openwork mesh structure, the lower marginal part sealingly abuts against a wall part in the vertical assembly of the envelope, this wall part having an inlet formed by a slot (7) in the horizontal assembly, whose horizontal edges (13, 14) have the shape desired to accelerate the gas stream entering towards the collecting means so that the gas current necessarily undergoes a change of direction of at least 900 before sweeping the assembly upwards as a whole and reaching then the outlet (6) from the envelope.   2 Device according to claim 1, characterized in that the envelope has a liquid outlet (6) located at the junction between the collecting means (9) and the envelope wall   (8), so that the collecting means is subjected to self-draining.   3 Device according to claim 1 or 2, characterized in that the flow of the outlet gas is generally horizontal, after a change of direction of about 90   suffered around the upper edge of the collecting means (9).   4 Device according to claim 1 or 2, characterized in that the flow of the outlet gas is on the whole   directed vertically downwards after a change of direction   tion of about 1800 suffered around the upper edge of the medium collector (8, 9).   Device according to any one of the claims   previous, further characterized in that the edges (3; 13) of the inlet (7) are shaped to deflect and / or exclude any liquid collected in service on the surfaces   internal and / or external of the envelope.