CA1151558A - Apparatus for separating solids and liquid components - Google Patents

Abstract

APPARATUS FOR SEPARATING SOLIDS AND LIQUID COMPONENTS
ABSTRACT OF THE INVENTION

An apparatus for separating solids and liquid components of different densities from a fluid mixture or emulsion. The apparatus is comprised of a stack of vertically disposed spaced plates that are positioned within a container and between an inlet and an outlet.
The plates are corrugated and the fluid mixture flows from the inlet, and through the stack, parallel to the corrugations, whereby the solids in the mixture drop through to the bottom of the plates, and the light density liquid components flow up toward the top of the stack, while the heavy density liquid components pass through the lower portion of the stack and out towards the outlet.

Description

APPARATUS FOR SEPARATING SOLIDS A'ND LIQUID COM~ONENTS

BACKGROUND OF THE I'NVENTION
1. Field of the' Invent'ion This invention relates to plate separators for fluid mixtures, and more particul~rly to a separator ~apted ~or separating an oil/water mixture contaminated with solids, such as sand ox dirt.
~. Description of'th'e Prior Art .
In U.S. Patent Numbers 3,874,813 and 3,957,656, assi~n-ed to the same assignee as the assi~nee of the present in-vention, there is disclosed a system for eliminating oil from water using a stack of horizontally aligned corrugated plates. However, inasmuch as many oil/water mixtures con-tain solids, such as dirt or sand therein, the horizontally aligned plates provide no means for removing the solid materials while the system is operational~ Thus these solids collect between the plates and frequently clog the system. This results in the need for a regular main~
tenance cycle, whereby the system must be shut down in order to clean and remove the solid matter from the stack of plates.
OBJEC~ O~ THE INVENTION
It is therefore an object of this invention to 25 provide an improved apparatus ~or separating liquid components from a fluid mixture, which mixture ma.~ be contaminated wi.th solids, such as dirt and/or sand.

.~ ' . : .

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It is another object of this invention to pro~
vide an appaxatus for separating oil from water wherein such apparatus has no need for a separate maintenance cycle to remove solids ~rom its coalescing plates~
This and other objects will be pointed out hereafter.
SVMMAR~ OF TEE: INVENTION
According ~o a broad aspect of the invention there is provided an apparatus for separating solids and liquid components of different densities from a ~luid mixture or emulsion. The apparatus includes at lsast one stack of vertically disposed spaced plates that are positioned within a container and between an inlet ~or introducing the fluid mixture into the con-tainer and outlets for discharging the separated liquids from the container. The plates have approximately sinu-soidal cross sectional corrugations positioned parallel to the flow of the mixture, which corrugations ~orm al,ernately constricting and expanding passages. A V
shaped trough is positioned beneath and in juxtaposition with the stack of plates for collecting and removing solids which are separated from the mixture during the passage of the mixture through the stack~ The plates have bleed holes therein at the peaks o~ the corruga-tions to allow ~or equilization of pressure between ad-jacent regions of the stack.
BRIEF DESCRIPTION OF THE DRAWINGS
.
Figure 1 is a cross section of a vertical plate separator in accordance with the invention;
Figure 2 is a partial cross section of some vertically positioned plates within the apparatus shcwn in Figure l;

~ igure 3 is another partial cross section of a pair of plates illustrating a means for e~fectuating a desired spacing of these plates; and Figure 4 is an isometric view of a plate em-ployed in the apparatus of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
. .
Referring to Figure 1, -an apparatus fox ~epa-rating solids and liquid components of different dens-ities in a fluid mixture or emulsion is provided within a container 10, which aontainer can be constructed of any suitable material, such as mild steel coated with co~l tar epoxy on the inside surfaces and epoxy paint on the exterior sur~aces thereof. All internal com-ponents of the apparatus are constructed of plastic, stainless steel or a steel coated with coal tar epoxy so as to be uneffected by most corrosive chemica?.s.
Container 10 has a flanged intake pipe 12 at one end, and a flanged discharged pipe 14 at another end thereof. A transverse manifold 16 is connected to intake pipe 12, and has two or more vertical distri-bution pipes 18 connected thereto. Each distribution pipe 18 can have a plurality of holes 20 on a portion thereof, which holes generally face an adjacent con- -tainer wall 22. The fluid mixture, which in the pre-ferred embodiment is comprised of solid materials (dirt or sand~ and oil dispersed within water, enters through intake pipe 12 so as to be fairly evenly distrib-uted throughout the intake end of container 10. Vents 24 are provided at the top of vertical distribution pipes 18 to permit the escape of excess gasses.
Even distribution of the i~fluent fluid mixture is desired in order t~ minimize turbulence w~ich would otherwise impede sep~ration of the solids ~nd liquid components. Further ~low equalization may be achieved by using a flow equalization baf*le 26 that is comprised of a plurality of parallel vertically spaced slats.
The mixture, which has passed through the flow equalization ba~le 26, next enters a stack 28 o~ vert-ically disposed spaced plates. Separation of the solids and liquid components is enhanced by dividing the in-fluent flow into thin layers by using closely spaced plates to ~orm flow passages. Portions o~ thxee adja-cent plates 30, 32 and 34 are shown in Figure 2, wherein th~ lighter liquid components, such as oil tends to coalesce on a sur~ace of any adjacent plate, and move towards the top of that plate as symbolized by the up-wardly directed arrows, while the heavier water passesthrough the lower portions of the plates. Referring`now to the adjacent surfaces of plates 32 and 34, solids coalesce on plate 32, and being heavier than the oil and water, these solids slide down along the surface of one sloped section of that plate, and after passing a peak or crest 36 in that plate, the solids cascade straight down and coalesce on the adjacènt sur~ace of plate 34 as sym-bolized by the downwardly directed arrows. The solids continue their downward movement along a succeeding sloped section of plate 34, until they reach a crest or peak 38 in that plate, and the solids then cascades vertically down to the next succeeding sloped surface of adjacent plate 32. The sloped sections o~ plates 30, 32 and 34 should be approximately at an angle o~ 45 to 85 wi~h the horizontal plane in order to insure that enough momentum is imparted to the separated solids so that they continue their downward movement within the plat~s until they eventually collect at the bottom of the stack in a trough 40. Trough 40 positioned beneath and in juxtaposition ~lSS8 wich stack 28, provides a means for collecting and re-moving the solids. The solids collected within the bottom of trough 40 can be removed from container 10 by injecting or forcing a stream of liquid through a port on one side (not shown) of the container at one end of the trough and out through a port 42 on the o~her side of the container at the other end of the t~ough.
In accordance with the invention, and as shown in Figure 2, flow passages 44 o~ stack 28 are made to alternately constrict and expand. The fluid mixture passes therethrough, and therehy alternately acceler-ates and decelerates in a gently pulsating manner. In the case of an oil/wa~er mixture, the oil (the dispersed medium) is in the form of drops of vaxious sizes. As a small oil drop collides with a larger oil drop, they coalesce into a still larger drQp. Coalescence, and consequently liquid component separation, can be en-hanced bv increasinq the freauencv of collision of the drops. During acceleration or deceleration. oil dro~s will move at a rate proportional to their size. Rela-tive motion between dro~s of di$ferent sizes therefore occurs, therebv increasinq the collisions by an amount in excess over which would otherwise occur under con-stant velocitv conditions.
The nature of the fluid mixture is such that thedis~ersed medium is so finelv defined that it will not se~arate by gravity alone (at least not for an inad-vertently long period of time). In fact a typical a~-26 lication of this invention is in the treatment of anoil/water mixture which has already been subjected to gravity separation. The coalescing of the minute drops of oil is consequently necessary for separation from the dispersion medium, such as water. The larger the oil drops the faster they Will rise~ The plates of stack 28 are vertically positioned~ so that the corrugations in the plates are positioned parallel to the ~low of the fluid mixture between intake pipe 12 and discharge pipe 14. This enhances the probability that oil will coalesce on the surfaces o~ the ver~ical stack of plates.
On the other hand, if the plates were vertically posi-tioned so that the corrugati`ons were perpendicular to the flow of the mixture therethrough, there is a greater chance that the finely dispersed o;l droplets would pass right through the s~ack without ever coalescing on a plate , the results of which would be that oil would still remain dispersed in the water exiting the container at discharge pipe 14~
Although many forms of alternately constricting and expanding passages can be defined, some design re-strictions exist. If changes in the size of the pas-sages are made angular or abrupt, turbulence will be in-duced which will tend to break up coalesced oil drops rather than to form them.
As shown in Figure 2, stack 28 is comprised of a plurality of thin plates having a wavy cross section.
Also as shown in Figure 2, plates 30, 32 and 34 are in the form of a sine wave having a Pitch P and an ampli-tude A. The plates are preferably made of oleophilic makerial having a desired thickness T, and have a max-imum spacing therebetween.
One example of plate separator dimensions which can be used are as follows:
P = 2.66"
A = 1"
T = 0 060"
S having a range from 1/8" to 1"
An example of oleophilic matexial that can be ii5S8 used for the plates is polypropylene or fiberglas, While the plates in Figure 2 have a sine wave configuration, the corrugations can be made to approximate a sine wave as shown in Fiqure 3, wherein plate~ 44 and 46 can be comprised of narrow straight sections which are connected by wider curvilinear sections.
Also as illustrated in Figure 3, a tie rod ~8 in conjunction with a spool 50 are used to establish the desired spacing between the plates.
As illustrated in ~igure 4, bleed holes 52 are pro-vided at the peaks or crests of the plates so as to egual-ize pressure wi~hir. stack 28, and prevent a pressure im-balance due t~ a large buildup of oil or solids in one regicn of the stack. Semicircular bleed holes ma~ also be provided at the edge/ends of the plates which together with similarly loca~ed semicircular bleed holes in ad-jacent plates combine to form circular bleed ho:'es.
Certain bleed holes may be used to contain tie rods which help ~orm and hold a unitary stack of plates hav-ing an appropriate space between the plates.
When treating some fluid mixtures, adequate solidsand liquid components separation may be achieved solely by the use of the apparatus so far described. In other instances, the addition of coalescing filters 54 (as shown in Figure 1) may enhance the process. Satis-~actory resul~s have been achieved for oil water separa-tion using Industrial Scott~Foam, produced by Scott Paper Company, as a filter material. Other suitable types of filter material can be provided by a brush like material having a randomly oriented oleophilic ~ibrous matrix, wherein the fibers have a mean diameter of less ~han approximately 150 microns.
If ~urther solids and liquid components separa-:~51S5~3 tion would be required, an additional vertically dis-posed stack 56 of plates shown in Fiqure 1 can also be used, wherein the space between the plates of stack 56 are less than the space between the plates of stack 28.
In such an instance, the space between the plates in stack 28 could be l/2", while the space between the plates in stack 56 could be 1/4". As also shown in Figure 1, a trough 58 will be positioned beneath and in juxtaposition with stack 56 and have a port 60 at one end thereof. Trough 58 and port 60 will operate in the same manner as and sarve the same purpose as trough 40 and port 42 located beneath stack 28.
Flanged discharge pipe 14 is connected to a trans-verse manifold 62 which has two or more vertical col-lection pipes 64 depending therefrom. Collection pipes64 can have a plurality of holes 66 within a portion thereof that face a container wall 68. It should be noted that while distribution pipes 18 extend up to the surface of the mixture, collection pipes 64 are de-signed to collect liquid well below the surface so asto avoid draining from the container the less dense components that have been separated and are confined to the top of the liquid body after passing through stack 56. A vent 70 is provided ~o avoid a siphonin~
action which might otherwise tend to empty out container 10. In this example the dispersed medi~m , i.e~ oil which has been separated after passing through stack 56, collects at the top of tha liquid to form a layer of film over a water effluent, which water effluent will be discharged through pipe 14. A float 72 is attached to a pivot arm 74, and supports a flexible conduit 76, which conduit is held within a collar 78. Conduit 76 is open at its top so as to drain therethrough the oil film which has collected. The position of the conduit ss~ :

within collar 78 is preferably made to be adjustable in order to permit a change in the position of its open end in order to adapt it to vaxious thicknesses of oil film which may be formed A cover 80 is provided for container 10 in order to minimize oxidation of parts of the apparatus, and also to permit the apparatus to be placed out doors.
An access cover 82 ~or container cover 80 is provided, so that when the access cover is removed, filters 54 can be reached and may be replaced or removed for clean-ing. Similarly another access cover 84 for container 80 is provided, so that when access cover 34 is removed, float 72 and the position of the open end of conduit 76 can be readily adjusted.
Although this invention has been described with reference to a specific embodiment thereof, numerous modifications are possible without departing from the invention, and it is desirable to cover all modifications falling within the spirit and scope of this invention.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1) Apparatus for separating solids and com-ponents of different densities in a fluid mixture or emulsion comprising:
a) a container;
b) inlet means for introducing said mixture within said container to minimize turbu-lence within said container;
c) first discharge means for removing a more dense component at a level below the level of a less dense component;
d) at least one stack of vertically dis-posed spaced plates positioned within said container and between said inlet means and said first discharge means, said plates having approximately sinusoidal cross sectional corrugations positioned parallel to the flow of said mixture, said corruga-tions forming alternately constricting and expanding passages;
e) second discharge means, positioned on the same side of said plates as said first discharge means, for removing the less dense component at a level above the level of the more dense component; and f) means, positioned beneath and in juxta-position with said plates, for collecting and then removing said solids.

2) Apparatus for separating solids and com-ponents of different densities in a fluid mixture or emulsion according to claim 1, further comprising:
a second stack of vertically disposed spaced plates positioned within said con-tainer and between said one stack and said first discharge means, wherein the space between the plates of said second stack is less than the space between the plates of said one stack.

3) Apparatus for separating solids and com-ponents of different densities in a fluid mixture or emulsion according to claim 1, wherein said spaced plates have bleed holes therein at the peaks of said sinusoidal cross sectional corrugations to allow for equalization of pressure between adjacent regions of said one stack.

4) Apparatus for separating solids and com-ponents of different densities in a fluid mixture or emulsion according to claim 1, wherein said solid col-lecting and removing means is comprised of a trough, whereby a stream can enter one end of said trough and exit an opposite end of said trough to flush the col-lected solids out from the bottom of said trough.

5. Apparatus for separating components of different densities in a fluid mixture, said apparatus comprising a container, an inlet for introducing said mixture into said container, first discharge means for removing the more dense component of said fluid mixture at a level below the level of said less dense component, a plurality of plates in said container, each of said plates extending vertically from a point adjacent the upper surface of said fluid mixture toward the bottom surface of said fluid mixture and also extending generally in the direction of fluid flow between the inlet and first discharge means to define vertically extending fluid flow paths between said plates between the inlet and the first discharge means, said plates having corrugations extending parallel to the direction of fluid flow such that the distance between each of said plates and a corresponding adjacent plate varies along the surface of the plate between the upper surface of said fluid mixture to the bottom surface thereof so that the width of the fluid flow paths varies at different horizontal cross sectional planes taken through said plates, and second discharge means for removing the less dense component at a level above the level of the more dense component.

6. Apparatus for separating fluid components of different densities in a fluid mixture according to claim 5, in which the fluid flow paths between one of said plates and corresponding adjacent plate have a substantially sinusoidal configuration.

12 ,. Apparatus for separating fluid components of different densities in a fluid mixture according to claim 6, in which said corrugations are substantially sinusoidal in a cross sectional plane transverse to the direction of fluid flow.

8. Apparatus for separating fluid components of different densities in a fluid mixture according to claim 7, in which each of said corrugations has a series of peaks alternating with connecting sections interconnecting said peaks, the peaks of each plate nesting within the peaks of a corresponding adjacent plate, the spacing between the peaks on one of said plates to corresponding peaks on an adjacent plate being greater than the spacing between the adjacent connecting section on said one plate and the corresponding connecting section on said adjacent plate.

9. Apparatus for separating fluid components of different densities in a fluid mixture according to claim 8, and bleed holes in at least some of the peaks of at least some of the plates to equalize pressure across the plates.

10. Apparatus for separating fluid components of different densities in a fluid mixture according to claim 8, and structure interconnecting at least some of the peaks of some of the plates with a corresponding peak of an adjacent plate to regulate the spacing between the plates.