FR2513898A1 - AIR CLEANER CONTAINING A SPRAY MIST - Google Patents

Abstract

THE INVENTION RELATES TO AIR CLEANERS CONTAINING MIST. IT RELATES TO A SCRUBBER IN WHICH THE GUIDING SURFACES 5 ARE SHAPED BY PLATES ARRANGED IN A 180 SENSITIVE CIRCLE ARC. DEFLECTORS 21 TRANSMIT WATER AND AIR ALONG THE GUIDING SURFACES. THESE ALLOW THE REMOVAL OF VERY SMALL DIAMETER PARTICLES. APPLICATION TO THE PURIFICATION OF GASES FROM PAINTING CABINS.

Description

The present invention relates to an air purifier containing a fog

formed by spraying in

  a cabin in which a paint is applied by pul-

  verifying on automobiles or the like.

  Excess spray in a cabin

  paint forms a superfluous paint mist, in addition to

  board in the air and adhering to the inner walls of the cabin.

  no and in particular, this fog deteriorates the atmosphere

  in which there are workers

  following precautions to avoid unwanted consequences

  (1) The cabin has a ceiling incorporating a

tif that transmits fresh air.

  2) The cabin has a discontinuous floor, and ventilators

  and exhaust chambers extract the air containing the spray mist, downwards and from the ground so that the fog is separated from the air and the purified air formed is then transmitted to the the ambient atmosphere. 3) Purification water is used to come in contact with the air containing the fog, below the ground and upstream of the fan so that the fog

  trapped in the air and that it is purified.

  (4) The water that trapped the fog is transferred to a separation bath in which a slurry of the pulverized material separates from the water, the resulting clean water being returned by pumps for new. Processes commonly used for the

  putting the air containing the fog in contact with sewage water

  as indicated in the preceding paragraph (3), comprise a projection method, as shown in FIG. 1 of the appended drawings, a deflection method as shown in FIG. 2, and combinations of these two basic methods,

  as shown in Figures 3 and 4 of the accompanying drawings.

  On these, the references A and W respectively designate

  air containing spray mist and purifying water while reference numeral 1 designates a throwing plate and reference 2 a deflection plate Although the above four methods have advantages and

  disadvantages, they pose a common problem because the

  fog separation is not satisfactory, and in particular, it does not ensure a total separation of a fog whose particles have a small dimension

  (diameter less than or equal to 10 microns).

  In view of the disadvantages of the

  The invention relates to a method ensuring

  very high fog separation.

  Other features and advantages of the

  will be better understood by reading the description

  which will follow examples of embodiment and with reference to the accompanying drawings in which: Figures 1 to 4, already described, are sections

  each illustrating the operating principle of a

  known source of air containing mist formed by spraying

tion; -

  Fig. 5 is a diagram illustrating inertia separation; Figures 6a to 6d are schematic sections each showing an example of a concave guide surface; and FIGS. 7 to 11 are sections of different air purifiers containing a mist according to the invention,

  FIG. 7 being a vertical section of a scrubber almost -

  complete while the other figures are vertical cuts

  essential parts of scrubber variants.

  We first consider, by way of illustration, the

  figure 5 for the description of the separation by inertia

  which constitutes the essential process of this separation, by implementing the resistance represented by the Stokes equation. In FIG.

  concave guide intended to guide the air containing the fog

  lard and purifying water, the reference 4 designates an inlet to the guide surface, the reference O designates the center of curvature of the surface 3, cx denotes an angle in the center, R, the effective radius obtained by subtraction. half of the transverse dimension b of the inlet 4 of the radius of curvature of the surface of quidane, and 1 the velocity of the air flow at the inlet 4. the air velocity, as a first approximation, and if we assume that the radius R is much greater than the

  the distance X (d) of radial displacement to the outside

  fog particles under the action of the forces

  in the angle c, is given by the following equation:

  where p (p ep -1) 2 X (d) = _ (1) 1 in which d denotes the particle diameter, for example in meters, fp the density of the particles, e the density of the air and the kinematic coefficient of viscosity of the air When X (dc) = b, dc being a critical diameter of trapping, the particles whose diameter exceeds d are trapped in water while those whose diameter d is less than to remain in the air In other words, the larger the diameter

  is small and the trapping of particles is difficult.

  The reduction of the critical trapping diameter requires, in the preceding equation (1), (1) the increase of "or the increase of the circumferential length L,

  (2) the reduction of X (d) or b, or (3) the increase of v.

  The invention essentially relates to characteristic (1).

  In an air purifier containing spray mist, in a spray booth according to the invention, a concave guide surface is directed downward from a downward flow wall of scrubbing water so that that the water and the air containing the mist are guided, the guide surface having a continuous circular arc shape or the like which has a vertical surface or the like in an intermediate position between the upper and lower ends, and departing tangent portions

  upper and lower extremities in a horizontal direction

  in a direction slightly inclined with respect to a horizontal, an inlet passage being delimited along an upper portion of the guide surface so that it permits

  the circulation of the air containing the fog.

  The nature of the aforementioned concave surface of guiding

  In this example, the guide surface may have an initial upper point.

  Pl, P 2 or P 3 and a lower end point QI, Q 2 or Q 3.

  The points P1 and Q0 are just above and below the center of curvature O of the circle E The points P 2, P 3, Q 2 and Q 3 are in positions for which the tangents form lower angles or equal to 400 and preferably less than or equal to 300, preferably 150, relative to

at the hospital.

  The shape of the guide surface with respect to the circle E may be such that this surface 5 coincides with

  circle E as shown in Figure 6a, a higher half

  upper half of the surface 5 deviating outwardly of the circle E, as shown in Figure 6b, a lower half deviating from the circle E as shown in Figure 6c, or both in; The examples of FIGS. 6 b to 6 d may have a surface -dévié guide Although the importance of this deviation from the circle at the center of curvature or the radius is not primordial, this deviation or deviation is preferably minimal.

  designates downward walls for the circulation of

ration.

  As the preceding examples show, the critical trapping diameter of the fog particles

  much less according to the invention compared with that of

  these known by the use of a concave guide surface having a sufficient circumferential length, the behavior being theoretically represented by the equation

  (1) In other words, simple improvements in the structure of

  ture of the guide surface give important advantages

  compared to known constructions, so that

  The smaller particles are separated with the same separation efficiency, while the particles of the same size are separated with greater separation efficiency. According to the solution (2) previously considered, the inlet passage through which the air containing the fog penetrates, can be partitioned In particular, a passage

  divided in two has advantages because (1) the dia-

  The particle size of the particles that can be trapped is reduced compared to the prior art since the input dimension b is halved while the speed of the current remains the same, (2) as the trapping diameter does not change,

  that is, the dimension b remains the same as in the

  If the wind speed is not partitioned, the circulation velocity V is equal to 1/2 F, and the pressure drop is thus twice as low.

  and allows for energy savings, and (3) the speed of the

  can be determined at a value between

  values of the two cases (1) and (2) which precede (Q = S x v).

  When implementing the invention, the technique (3) can be used perfectly in combination with

techniques (1) and (2).

  Reference is now made to Figures 7 and 8 on

  Reference 7 designates a spray booth

  the reference 8 of the walls, the reference 9 a floor

  continuous, the reference 10 an object to be painted, for example an automobile body, the reference 11 a tank, the reference 12 of the purge water supply distributors, the reference 13 slightly inclined washing trays to evacuation ports, and references 14 and 15 of the elongated and continuous plates forming partitions

  and whose outer surface plays the role of the walls 6 of

  The reference 16 designates lower plates

  inclined channels, the reference 17 a purge channel and the

  reference 18 a duct joining an evacuation chamber.

  The broken lines A represent the air currents and the solid lines Wel the currents of water The points designate

  fog particles Reference 19 designates

  elongate and continuous guide shaped cups, having circular arcs covering 180 and delimiting

  Concave concave surfaces 5 on their internal face.

  20 denotes projection plates which bow

  down and that can be eventually removed.

  Reference 21 designates guide plates forming a step

  22 of introduction of the air containing the fog along the upper portions of the guide surfaces 5 The guide plates 21 also receive the purification water which

  overflows the walls 6 and the passage 22 have a joint opening

  mune 23 opening into the cabin 7 In these modes of

  the two guide plates 19 are placed one

  the other so that the removal of the paint tips adhering to the guide surfaces is much easier

  thanks to large openings formed on 180 a.

  Preferably, the guide surfaces 5 are coated with

  "Teflon" or other material that effectively binds the adhesive

  of fine paint particles.

  The purification of the air containing the fog

  is performed by inertial separation at the surface

  these 5 and by shock separation at the plates 20

projection.

  FIG. 9 represents a variant of scrubber in which the two guide plates 19 are arranged opposite each other and have a common plate 20 of

  projection A central feed distributor 12 is placed

  between the air guide plates 21 so that the waste water

  ration flows through the orifices 23 formed in the upper

guides 21.

  The variant of FIG. 10 comprises an opening

  23, a guide plate 19 and a guide plate 21.

  In FIG. 11, the wall 6 of the downstream current

  and the entrance passage 22 communicate with the cabin 7

  by separate orifices 23 'and 23 ".

  Although the plate or the plates 20 projection

  Figures 8 and 9 are deleted in the

  10 and 11, the latter embodiments may also comprise circular-shaped projection plates as in the embodiment of FIG. 8 or a flat plate perpendicular to the air currents and

  of water, as shown in Figure 9, as part of the

  vention. Of course, various modifications may be made by those skilled in the art to the devices which have just been described as non-limiting examples only.

  without departing from the scope of the invention.

2513898-

Claims (4)

  1 Purifier for purifying air containing a mist formed by spraying, by contact with purifying water, characterized in that it comprises at least one concave guide surface (5) directed downwards from at least one wall (6) of downward flow of purifying water for this water and the air containing the mist to be guided, the guide surface having a continuous arcuate shape or the like comprising a surface vertical or the like in an intermediate portion between upper and lower ends, and tangential portions extending from the upper and lower ends in a horizontal direction or in a direction slightly inclined with respect to a horizontal, and an inlet passage (22) delimited on the along an upper part of the surface   (5) so that it allows the passage of air containing fog.   2 A scrubber according to claim 1, characterized   in that the guide surface (5) is in the form of a   arc of circle covering an angle in the center of 1800 approximately.   3 A scrubber according to claim 2, characterized   in that the wall (6) of downward flow and the   entrance (22) have a common orifice opening into a spray booth.   4 A scrubber according to claim 1, characterized   in that the inlet passage (22) also forms a surface flow of sewage water.   A scrubber according to any one of claims 1 to 3, characterized in that the inlet passage (22) for the introduction of air containing the mist is drifted to the right and to the left in an intermediate position   transversely to the orifice (23).