US2400623A - Mist eliminator - Google Patents

Description

y 1945- J. B. BAiRD ETAL I ,5

' MI-ST ELIMINA-TOR Filed Oct. 18,1943 2 Sheets-sheaf 1 w au/ 1:. Dad/57;. u) Ialm B. Baird.

IN V EN TORS.

May 21,, 3946. J. B. BAIRD ET :AL

MIST ELIMINATOR Filed Oct. 18," 1943 2 Sheet-Y-Sheet 2.

P Dearmin.

am Jo/u'l- Baird INVENTORS.

B. M w/ Patented May 21, 1946 MIST ELIMINATOR John .BQBaird and Paul E. Dearmin, Houston,

Tex., assignors to Hudson Engineering Corporation, Houston, Tex, a corporation of Texas Application October 18, 1943, Serial No. 506,714

1 Claim.

This invention relates to a structure'commonly known as a mist eliminator and has for its general object the provision of such a structure which will with greater efficiency than heretofore known remove from a stream of air or gas a mist consisting of liquid particles or the like suspended therein.

The immediate purpose of the mist eliminator to which this invention relates has to do with its use as a means of preventing escape from a cooling tower of mist which may become entrained in and suspended in a stream of air passing through the cooling tower. Such stream of air may pass through the cooling tower by natural means such as by a draft due to convection or due to natural winds, or may be passed through the cooling tower by virtue of the use of fans or the like. Considerable difficulty has been experienced in the past in connection with cooling towers in that the air coming from the tower is apt to carry with it a considerable amount of liquid in the form of a suspended mist. In many localities the actual loss of water in this manner represents a serious difficulty due to the scarcity of water and the difficulty of obtaining the same, while i other localities the presence of the excessive moisture carried out by the stream of air may cause considerable inconvenience and damage to property in the immediate vicinity and in the path of the stream of air.

In any event, it is highly desirable that a means he provided for preventing the stream of air leaving a cooling tower or like structure from carrying with it a substantial amount of moisture in the form of mist and structures devised in the past for this purpose have been able to accomplish it only with a relatively low efiiciency.

While immediate application of this invention is to the problem of preventing the escape of mist from a cooling tower, it will be appreciated that the invention itself is applicable to any situation in which it is desired to eliminate the particle of mist which may be suspended in an air stream or gas stream. Thus, it might readily be used in the place of the usual louvers which are employed in connection with ventilating openings in buildings and the like, to prevent rain and other forms of condensed moisture from being carried into the building by wind or the natural flow of air into the building through the ventilating opening.

It will be appreciated also that while the invention is illustrated in the drawings as being employed in one position only, it may be employed in other positions if so desired.

It is, therefore, a more specific object of this invention to provide a mist eliminator which is capable of general use wherever it is desired to eliminate suspended condensed moisture from an air stream or gas stream.

Another object of this invention is to provide a mist eliminator especially adapted for use in connection with cooling towers for preventing the escape of moisture therefrom through the 'air stream passing through the tower.

Another object of this invention is to provide such a structure which will perform the indicated function with a greater degree of efiiciency than have structures heretofore devised.

Other objects and advantages of this invention will become apparent from the following descrip-' tion taken in connection with the accompanying drawings wherein is set forth by way of illustration and example only and not by way of limitation, a single embodiment thereof.

In the drawings:

Fig. 1 illustrates a side elevation of a cooling tower of the forced draft variety, with parts broken away in order to illustrate the installation of a mist eliminator constructed in accordance with this invention. a

Fig. 2 is a View on an enlarged scale illustrating a mist eliminator constructed in accordance with this invention and showing the outer or downstream face thereof.

Fig. 3 is a transverse cross section through the mist eliminator illustrated in Fig. 2, taken along the line 3-3 of Fig. 2.

Referring more in detail to the drawings, the cooling tower illustrated in Fig. 1 is supported upon any suitable fundation l and is provided with a lower wall section 2 having openings 3 therein in which are disposed suitable power fans 4. These fans are adapted to draw air into the cooling tower through the openings 3 and force it up through the interior of the cooling tower which may be of any suitable and usual cooling tower construction and forms no part of this invention. The upper portion of the cooling tower may be enclosed as illustrated by mean of suitable wall structure 5 and the interior of the cooling tower will be provided with any suitable supports such as the uprights illustrated at 6. Such supports or supports similar thereto are conventionally used in connection with cooling towers of this time.

Extending between adjacent pairs of supports 5 are support beams 1 adapted to receive and support the mist eliminator units constructed in accordance with this invention and illustrated in Figs. 2 and 3.

illustrated an intermediate spacing and tying member I I) which is similar in all respects to the spacing and tying member 3 but which is not secured to uprights 6 and merely rests upon a intermediate portion of the beams I.

Referring now more in detail to the mist eliminator elements, it will be seen that these consist of a plurality of vanes arranged in groups and that the groups are nested with respect to each other. In the form illustrated, four vanes make up each group, these being a relatively narrow vane I I disposed adjacent the intake or upstream side of the mist eliminator, a wider vane I2 which is disposed at substantially right angles to the vane II and is inclined in the opposite direction with respect to the intake and discharge planes of the mist eliminator section. The vane I2 it will be noted is in contact with one edge of the vane I I and extends past the vane I I so as to provide a portion projecting below the vane II as seen in Fig. 3.

Similarly, a vane I3 which is of a width similar to the vane I2 is disposed transversely with respect to the vane I2 and in contact with the upper edge thereof as seen in Fig. 3, but extends past .the vane I 2, in substantially the same manner that the vane I2 extends past the vane II. In the form illustrated, this vane I3 is substantially parallel to the vane I I.

Extending transversely of the vane I3 at the outlet side of the mist eliminator is a fourth vane I4, the same being disposed substantially parallel to the vane I2 in the form illustrated. This vane I I is comparable in width to the vane II but extends across the edge of the vane I 3 so as to project by substantiall equal amounts on opposite sides of the vane I For the sake of convenience in reference, the lower side of the mist eliminatoras seen in Fig. 3

will be referred to herein as the rear or upstream side, and the upper side as shown in Fig. 3 will be referred to as the front or downstream side, it being understood that flow is adapted to take place through the eliminator from the lower side as seen in Fig. 3 to the upper side. In other words, the lower side as seen in Fig. 3 might be referred to as the inlet side whereas the upper side might be referred to as the discharge side.

Also, for the sake of convenience, that face and edge of each of the vanes which are disposed toward the bottom or inletside as seen in Fig. 3 may be referred to as the rear edge or face or the upstream edge or face, and the edge and face of each vane which appears uppermost in Fig. 3 may be referred to as the forward edge or face or as the downstream edge or face as the case may be.

It is further noted that the portion of the vane I2 which projects rearwardly past the vane I I forms with the vane I I a V-shaped channel which will serve to catch mist and condensate and prevent it from passing through the device. A similar mist catcher will be formed by that portion of the vane I3 which projects rearwardly past the vane I2, in cooperation with the adjacent porwill be formed by that. portion of the vane I 4 which projects past the forward edge of the vane I3 and extends rearwardlyof such forward edge.

In each case, the V-shaped space thus formed between the rearwardly projecting portion of one vane and the portion adjacent the forward edge of the adjacent vane will serve as a rearwardly open mist catcher to catch and conduct away mist or condensate removed from the stream of air or gas passing through the device.

It is further to be noted that each of the vanes II, which incidentally extend more than half of the shortest distance between the adjacent vanes I2 of two adjacent groups, but less than the ful1- distance between such vanes, will serve to prevent the streamline flow of air or gas into the space between these vanes I2 but will not serve to substantially obstruct such flow except for the retarding influence which will be inherent in the turbulent flow thus produced. Likewise, the pro-, jections which form portions of the respective mist collectors above referred to serve to create turbulence in the air or gas as it flows throughthe eliminator, and air or gas issuing from the eliminator is prevented from streamline flow out from between two adjacent vanes I 3 of adjacent. groups of vanes by the forwardly projecting portion of the vane I I.

The groups of vanes II, I2, I3 andi are 'ar-' ranged as illustrated in nested position with respect to each other so that theyform between them zigzag passageways. having meansat each end and at each bend in the passageways for the collection of mist and thecausing of turbulence in the air or gas flow through the device, and

having additional means at each end of each I mist laden as to appear as a dense fog, and upon being blown through the mist eliminator herein described issued as a stream of air in which no condensed moisture could be detected by the senses of sight or feeling or by the expedient of holding a dry cotton cloth in the path of the issuing stream of air for a substantial period.

It will thus be seen that a means hasbeen provided which is fully capable of carrying out and achieving the objects of this invention.

It will be appreciated that While in the cooling tower illustrated the mist eliminator constructed in accordance with this invention is arranged in a horizontal position at the top of the'tower, it may also be used in a vertical position, preferably with the vanes or slats extending up and down,

members so that these tying and spacing members will not obstruct such flow along the channels.

It will further be appreciated that while .it is intended that the device'illustrated and described will operate most efficiently as a mist eliminator when the flow of air or gas passes into the device tion of the vane I2, and a third such mist catcher from the bottom as seen in Fig. 3 and out through the top thereof, air or gas flow may 'take place in the reverse direction through the device, thus making it possible for such mist eliminators to be used for example as the side walls of cooling towers in which the passage of natural winds transversely through the cooling towers is utilized instead of forced drafts such as in the cooling tower illustrated.

Having described our invention, we claim:

In a mist eliminator, a series of groups of vanes with the vanes of each group arranged in zig-zag fashion and the groups nested together with flow spaces therebetween, each group of vanes comprising more than two vanes, and each of the vanes other than the rearmost vane projecting rearwardly across and beyond and in contact with the forward edge of the vane to its rear, and a plurality of spaced parallel vane supporting plates positioned perpendicularly with respect to the vanes and having a plurality of slots of zig-zag formation therein extending continuously from adjacent the forward to adjacent the rear edges thereof, each slot having a plurality of joined sections angularly disposed with respect to adjoining sections, each section being of a shape and size to receive a single vane, and said. plates having openings formed therein extending between the rearwardly projecting portion of a vane receiving section of each slot and the forward portion of the vane receiving section of the slot rearwardly thereof.

JOHN B. BAIRD. PAUL E. DEARMIN.

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