CA1094961A - Screenless granular bed filter - Google Patents

Screenless granular bed filter

Info

Publication number
CA1094961A
CA1094961A CA293,263A CA293263A CA1094961A CA 1094961 A CA1094961 A CA 1094961A CA 293263 A CA293263 A CA 293263A CA 1094961 A CA1094961 A CA 1094961A
Authority
CA
Canada
Prior art keywords
passageway
inlet
filter
granular material
granular
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA293,263A
Other languages
French (fr)
Inventor
Frederick A. Zenz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DUCON COMPANY Inc (THE)
Original Assignee
DUCON COMPANY Inc (THE)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US05/759,969 external-priority patent/US4140497A/en
Application filed by DUCON COMPANY Inc (THE) filed Critical DUCON COMPANY Inc (THE)
Application granted granted Critical
Publication of CA1094961A publication Critical patent/CA1094961A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/30Particle separators, e.g. dust precipitators, using loose filtering material

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Filtering Materials (AREA)

Abstract

SCREENLESS GRANULAR BED FILTER

Abstract of the Disclosure A granular bed filter, capable of being back-washed, is disclosed without screens. The filter beds of granular material are generally U-shaped in section.

Description

10~ f;~

l Background Granular bed filters have at least an inlet screen and in some cases a bed support screen. See U.S. Patents 3,410,055 and 3,798,882.
~hen the temperature of the gas being filtered is high, surh as above 1600F, and/or contains for example 1.4% hydrogen sul-fide, the metallurgical requirements prohibit the use of metallic bed support screens or perforated plates. For the same reasons, an inlet screen cannot be used.
The problem solved by this invention is the provision of a granular bed filter lacking an inlet screen and lac~ing a support screen in a manner whereby the granular bed material is not lost during operation or during backwashing of the granular material which at least in part is subjected to cleaning by fluidization.
Summary of the Invention The granular bed filter of the present invention includes a housing having an inlet and an outlet. Walls of the housing are arranged so as to define at least one U-shaped passageway between ~ the inlet and outlet. A bed of granular filter material is supported -~ 20 in said passageway for filtering dirty gas flowing from said inlet to said outlet.
In the preferred embodiment of the present invention, the cross sectional area of the passageway at the end thereof communicat-ing with the outlet is greater than the corresponding area of the end of the passageway communicating with the inlet. Also, the size of the granular material in said passageway and exposed to the inlet is smaller than the size of the granular material in said passageway and exposed to the outlet.
It is an object of the present invention to provide a granular bed filter capable of operating at high temperatures without -' , ~

~0~ 9~jl 1 a support screen or inlet screen while at the same time providing a granular bed filter which may be backwashed by fluidizing at least part of the granular material.
Other objects will appear hereinafter.
For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the pre-cise arrangements and instrumentalities shown.
Figure 1 is a vertical sectional view through a granular bed filter in accordance with the present invention.
Figure 2 is a transverse sectional view taken along the line 2-2 in Figure 1.
Figure 3 is a perspective view partially cut away for il-lustrating another embodiment of the present invention.
Figure 4 is a sectional view taken along the line 4-4 in Figure 3.
Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in Figure 1 a granular bed filter in accordance with the present invention designated generally as 10.
The filter 10 includes a housing 12 having an inlet mani-fold 14 and an outlet manifold 16. The inlet manifold 14 is separated from the outlet manifold 16 by a partition wall 18. It will be noted that the partition 18 divides the interior of the housing 12 in a manner so that the inlet manifold 14 is substantially smalle} in cross sectional area than the outlet manifold 16.
The filter 10 includes a plurality of filter chambers having an inlet end communicating with the inlet manifold 14 and an outlet end communicating with the outlet manifold 16. The walls of the housing 10 for defining the filter chambers are preferably pre-
- 2 -10~'~961 fabricated so as to have their inlet end secured in a cut-out opening in the partition wall 18. Tn ~igure 1, the housing 12 includes filter chambers 20 and 22 which are identical. Hence only Eilter chamber 22 will be described in detail.
The filter chamber 22 is U-shaped in transverse section as shown in Figure 1 with a curved top wall 24 and a curved bottom wall 26 interconnected by side walls 28 and 30. The distance between the side walls 28 and 30 is less than the transverse dimensions across the housing 12 as shown in Figure 2.
An end wall 32 interconnects the upper edge of the walls 24, 26, 28 and 30 at the inlet end thereof. An inlet opening 34 is provided in the bottom wall 26. The filter chamber 22 communicates with the outlet manifold 16 by way of an outlet opening 36. While it is preferred to have the opening 36 at an elevation above the elevation of opening 34, they may be substantially the same elevation.
The bight portion and the portion of the legs of the filter chamber 22 is filled with a bed of granular material 38. The granular material 38 is preferably a coarse material such as Alundum particles having transverse dimensions of approximately one-quarter inch.
On the inlet end of the granular material 38, there is provided a thin layer 40 of fine granular material such as that disclosed in my above-mentioned application and the above-mentioned patents.
The cross sectional area of the filter chamber 22 adjacent the outlet opening 36 is substantially greater than that of the filter chamber 22 adjacent the inlet opening 34. In other words, the top and bottom walls 24, 26 are divergent adjacent the outlet opening 36. m e purpose of the enlarged cross sectional area adjacent the - outlet opening 36 is to reduce the superficial gas velocity thereby compensating for any increase in pressure drop due to the *Trademark 10~`1961 1 length of the filter path through the granular materials 38 and 40.
The layer of granular material 40 is spaced from the elevation of the inlet opening 34 by a distance 90 that the layer of granular material 40 may be fluidized in the space thereabove without flowing out of the opening 34. This feature is explained in greater detail in my above-mentioned co-pending application. With the layer of granular material 40 having a thickness of three inches, the upper surface thereof will be spaced from the lower edge of opening 34 by a distance of approximately seven inches.
The interface between the coarse granular material 38 and the layer 40 of fine granular material is preferably horizontally disposed to assure uniform fluidizing reverse flow gas distribution.
During backwashing, the layer 40 of granular material will be fluid-ized into the space thereabove without any lifting or fluidizing of the coarse granular material 38. The large interface between the materials 38, 40 assures that the reverse flow cleaning gas velocity will be insufficient to fluidize the coarse granular material 38.
The interface between the materials 38, 40 extends across the full width and length of the inlet end of the filter chamber 22.
Dirty gas at an elevated temperature with or without high-ly corrosive components is introduced into the inlet manifold 14.
The dirty gas enters the filter chambers 20, 22 through the inlet opening, is filtered as it passes downwardly through the layer 40 of fine granular material, is further filtered as it passes through the granular material 38, and then exits into the outlet manifold 16. When it is desired to clean the filter beds, backwash gas such as air is introduced into the outlet manifold 16 at a low pressure such as 80 psi above the operating pressure in manifold 16. The backwash gas flows through the coarse granular material 38 and envelopes any accumulated dust in the interstices between the coarse 10~ ~9~;1 1 granular materi~l 38. The backwash gas then passes upwardly through the interface between materials 38, 40 and fluidizes the granular material 38 into the space thereabove but below the elevation of the inlet opening 34. The backwash gas then passes out the inlet opening 34 into the inlet manifold 14. Accumulated contaminants in the layer 40 of granular material is removed therefrom as the mater-ial is fluidized.
In Figures 3 and 4, there is illustrated another embodiment of the present invention designated generally as 10'. The filter 10' includes a housing defined by the outer pipe 42 and the inner pipe 44 coupled together by way of a partition wall 46 which divides the annular space between the pipes into an inlet manifold 48 and an outlet manifold 50. It will be noted that the pipes 42, 44 are non-concentric so as to define a U-shaped passageway between the mani-folds 48 and 50 with the larger cross sectional area of the passage-way being provided adjacent the outlet manifold 50 for the reasons discussed above. Dirty gas is supplied to the inlet manifold 48 by way of the conduit 54r Clean gas from the outlet manifold 50 flows into the pipe 44 by way of holes 52. The filter 10' may have a plurality of fil-ter chambers along the length of the pipes 42, 44. The ends of pipe 42 are closed at each end by an end wall whereas the pipe 44 may be open at both ends or may be closed at one end depending upon the de-sired distribution of the clean àir therewithin. The U-shaped pass-ageway is filled with the granular material, coarse and fine as des-cribed above. The elevation of the fine granular material i8 spaced below the inlet opening 56 in accordance with the description set forth above so that the fine granular material is not lost when being backwashed.
When filters 10 and 10' are used with high temperature and/or corrosive gases, the walls of the housings may be made from 10'~496~

1 ceramic or refractory material. Preferably, the walls of the housing exposed to contact with the dirty corrosive gas are made from metal coated on its exposed surface with a thin layer of ceramic in accor-dance with conventional procedures utilized heretofore for making kitchen sinks, bathtubs, and the like. As will be apparent from the above description and the illustration in the drawings, the filter of the present invention is easily fabricated from readily available materials requiring little machining. For e~ample, the embodiment in Figures 3 and 4 has the advantage of permitting the use of readily available tubes with tube 44 being surrounded by tube 42. The U-shaped passageway, divergent at its outlet end, is attained by posi-tioning the tubes so as to be non-concentric. The absence of inlet screens or support screens decreases the cost of the filter while at the same time eliminating a component which is highly subject to corrosion.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A granular bed filter comprising a housing having an inlet and an outlet, walls of said housing defining a U-shaped passageway between said inlet and outlet, one end of said passageway communicating with said inlet, the other end of said passageway communicating with said outlet, and a bed of granular filter material in said passageway; the cross sectional area of said other end of said passageway being greater than the cross sectional area of said one end.
2, A filter in accordance with claim 1 wherein said granular filter material is in two sizes, most of the filter material being of a coarse size, with a layer of fine granular material overlying the coarse granular material only at the one end of the passageway, and with the top surface of said fine granular material being spaced below the inlet of said passageway by a distance sufficient to permit the fine granular material to be fluidized into the space thereabove during backwashing without the fine granular material being lost by passing through the inlet to said passageway.
3. A filter in accordance with claim 1 wherein said housing includes inner and outer non-concentric tubes with a partition extending between the tubes, said passageway being defined by the ID of the outer tube and the OD of the inner tube.
4. A filter in accordance with claim 1 wherein said housing includes a plurality of said passageways disposed one above the other, an inlet manifold communicating with each passageway inlet, and an outlet manifold communicating with each passageway outlet.
5. A granular bed filter lacking screens or perforated support plates for granular filter material comprising a housing having an inlet and an outlet, walls of said housing defining a U-shaped passageway, one end of said passageway communicating with said inlet, the other end of said passageway communicating with said outlet, a bed of granular filter material in said passageway, a cross sectional area of said passageway at said other end thereof being greater than the cross sectional area of said one end of said passageway, said U-shaped passageway being defined by spaced upper and lower walls which are imperforate in the area juxtaposed to the granular filter material.
6. A filter in accordance with claim 5 wherein a major portion of the granular filter material is coarse granular material with the remainder being fine granular material, a layer of the fine granular material being provided only at said one end of said passageway and being spaced from said inlet by a distance sufficient to permit the layer of fine granular material to be fluidized into the space thereabove without passing through the inlet to said passageway.
7. A filter in accordance with claim 5 wherein said housing includes inner and outer non-concentric tubular members, said U-shaped passageway being defined by a portion of the OD of the inner tubular member and a juxtaposed portion of the ID of the outer tubular member,
8. A filter in accordance with claim 5 wherein a plurality of said passageways are provided within said housing, said housing including an inlet manifold communicating with the inlet to each passageway, said housing including an outlet manifold communicating with the outlet of each passageway, said passageways being disposed at different elevations within said housing.
9. A filter in accordance with claim 7 wherein said inner tubular member is provided with holes communicating with said outlet.
10. A method comprising the steps of filtering gas to remove contaminants therefrom by passing the gas downwardly through one end of a U-shaped passageway defined by imperforate walls and containing a bed of granular filter material, and reducing the velocity of the gas as it exits from said U-shaped bed of filter material, and performing said filtering step without the use of screens or perforated support plates.
11. A method in accordance with claim 10 including using granular material of at least two sizes, the smaller size granular material being a minor portion of the granular material and being a layer not more than three inches high at the inlet end of the passageway and substantially below the elevation of an inlet to said passageway so as to provide sufficient space thereabove for fluidizing the fine granular material without loss of the fine granular material through the inlet during backwashing.
12. A method in accordance with claim 10 including using an imperforate portion of spaced non-concentric curved wall portions to define the U-shaped passageway.
CA293,263A 1977-01-17 1977-12-16 Screenless granular bed filter Expired CA1094961A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US05/759,969 US4140497A (en) 1976-10-18 1977-01-17 Screenless granular bed filter
US759,969 1977-01-17

Publications (1)

Publication Number Publication Date
CA1094961A true CA1094961A (en) 1981-02-03

Family

ID=25057630

Family Applications (1)

Application Number Title Priority Date Filing Date
CA293,263A Expired CA1094961A (en) 1977-01-17 1977-12-16 Screenless granular bed filter

Country Status (9)

Country Link
JP (1) JPS5390069A (en)
AU (1) AU500568B1 (en)
BR (1) BR7800121A (en)
CA (1) CA1094961A (en)
DE (1) DE2801479C3 (en)
FR (1) FR2377220A1 (en)
GB (1) GB1576175A (en)
IT (1) IT7819321A0 (en)
MX (1) MX4439E (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3204222C1 (en) * 1982-02-08 1983-07-28 Josef 8000 München Berger Separating device having loose granular working material
JPS63279308A (en) * 1987-05-12 1988-11-16 Honda Motor Co Ltd Positioning controller

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE197318C (en) *
FR1433133A (en) * 1964-05-09 1966-03-25 Metallgesellschaft Ag Padded filter box
JPS4714555U (en) * 1971-03-17 1972-10-20
JPS4845600U (en) * 1971-09-29 1973-06-14
JPS5219542B2 (en) * 1972-07-29 1977-05-28
US3795090A (en) * 1972-08-25 1974-03-05 Barnebey Cheney Co Fluid filter construction

Also Published As

Publication number Publication date
DE2801479A1 (en) 1978-07-20
MX4439E (en) 1982-05-04
IT7819321A0 (en) 1978-01-17
AU500568B1 (en) 1979-05-24
JPS5714206B2 (en) 1982-03-23
FR2377220A1 (en) 1978-08-11
GB1576175A (en) 1980-10-01
FR2377220B1 (en) 1983-01-14
DE2801479B2 (en) 1980-02-21
DE2801479C3 (en) 1980-11-06
BR7800121A (en) 1978-08-22
JPS5390069A (en) 1978-08-08

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