U.S. patent number RE33,812 [Application Number 07/564,316] was granted by the patent office on 1992-02-04 for diffuser for aeration basin.
Invention is credited to Norbert Schneider.
United States Patent |
RE33,812 |
Schneider |
February 4, 1992 |
**Please see images for:
( Certificate of Correction ) ** |
Diffuser for aeration basin
Abstract
A diffuser for introducing gas in bubbles into liquid held in an
aeration tank .[.comprising.]. .Iadd.having .Iaddend.a body member
having a backing surface and passaging extending from a gas inlet
to an outlet at the backing surface, and a flexible, gas permeable
membrane covering the backing surface and secured at its periphery
to the body member in sealing relationship thereto. The membrane is
.[.adapted to distend.]. .Iadd.distendable .Iaddend.and .[.move.].
.Iadd.moves .Iaddend.away from the backing surface upon delivery of
gas under pressure to diffuser, with the gas flowing through the
distended portion of the membrane and into the liquid in the form
of relatively small gas bubbles, and .[.adapted to collapse.].
.Iadd.collapses .Iaddend.into engagement with the backing surface
when gas under pressure is not delivered to the difuser. A check
valve .[.comprising.]. .Iadd.has .Iaddend.a movable valve member on
the membrane and a valve seat on the backing surface enables flow
of gas into the space between backing surface and the membrane, and
blocks flow of liquid into the passaging in the body member.
Inventors: |
Schneider; Norbert (D-5657
Haan, DE) |
Family
ID: |
6231118 |
Appl.
No.: |
07/564,316 |
Filed: |
August 7, 1990 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
714658 |
Mar 21, 1985 |
|
|
|
Reissue of: |
13158 |
Feb 10, 1987 |
04764314 |
Aug 16, 1988 |
|
|
Foreign Application Priority Data
|
|
|
|
|
Mar 21, 1984 [DE] |
|
|
3410267 |
|
Current U.S.
Class: |
261/62; 137/854;
210/221.2; 239/145; 261/122.2 |
Current CPC
Class: |
C02F
3/201 (20130101); B01F 3/04269 (20130101); Y02W
10/15 (20150501); Y02W 10/10 (20150501); B01F
2003/04297 (20130101); Y10T 137/789 (20150401) |
Current International
Class: |
C02F
3/20 (20060101); B01F 3/04 (20060101); B01F
003/04 () |
Field of
Search: |
;261/62,122-124 ;239/145
;210/221.2 ;209/170 ;137/533.17,533.21,854 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0028728 |
|
Oct 1980 |
|
EP |
|
0507294 |
|
Jan 1931 |
|
DE2 |
|
1254600 |
|
Nov 1967 |
|
DE |
|
6751014 |
|
Jan 1969 |
|
DE |
|
2035651 |
|
Jan 1972 |
|
DE |
|
1767497 |
|
May 1974 |
|
DE |
|
2261994 |
|
Jun 1974 |
|
DE |
|
2554738 |
|
Jun 1976 |
|
DE |
|
1609004 |
|
Jul 1976 |
|
DE |
|
2701656 |
|
Jun 1978 |
|
DE |
|
2647920 |
|
Jul 1978 |
|
DE |
|
2757860 |
|
Jun 1979 |
|
DE |
|
2942607 |
|
Apr 1981 |
|
DE |
|
3101526 |
|
Aug 1982 |
|
DE |
|
3316140 |
|
Nov 1983 |
|
DE |
|
0824376 |
|
Nov 1959 |
|
GB |
|
Other References
Enviroquip catalog excerpt, "Snap-Cap Diffuses", Feb. 1987. .
Parkson Corporation catalog excerpt, "Diffused Aeration Products",
date unknown. .
Nokia catalog excerpt, Catalog No. 8.6.0, Apr. 1977..
|
Primary Examiner: Chiesa; Richard L.
Attorney, Agent or Firm: Rosenblatt & Associates
Parent Case Text
This application is a continuation of application Ser. No. 714,658,
filed on Mar. 21, 1985, which is now abandoned.
Claims
I claim:
1. Diffuser means for use in an aeration basin for introducing gas
in the form of bubbles into liquid held in the basin, said diffuser
means comprising:
a body member having a backing surface and passaging in the body
member extending from a gas inlet .[.adapted.]. .Iadd.positioned
.Iaddend.to receive gas under pressure from a source thereof to an
outlet at the backing surface for delivery of the gas under
pressure thereto;
a flexible, gas permeable membrane covering the backing
.[.surfce.]. .Iadd.surface .Iaddend.and secured generally along the
periphery of the membrane to the body member in sealing relation,
the membrane being .[.adapted.]. .Iadd.positioned .Iaddend.to
distend and move away from the backing surface upon the delivery of
gas under pressure to the diffuser, with the gas flowing through
the distended portion of the membrane and into the liquid in the
form of relatively small gas bubbles, and being .[.adapted.].
.Iadd.positioned .Iaddend.to collapse into engagement with the
backing member when gas under pressure is not delivered to the
diffuser;
and check valve means comprising a movable valve member on the
movable with the membrane and a valve seat on the body member at
said outlet, the movable valve member being moved away from the
valve seat along with the membrane when gas under pressure is
delivered to the diffuser to open the check valve for allowing the
gas to enter the space between the member and the backing surface,
and the movable valve member being moved into sealing relationship
with the valve seat to close the check valve when gas under
pressure is no longer delivered, for blocking flow of liquid into
the passaging in the diffuser means; and
stop means comprising interengageable means on the body member and
secured to the membrane generally at a central portion thereof for
limiting movement of said central portion of the membrane away from
the backing surface to a predetermined position spaced apart from
yet being generally adjacent to the backing surface, whereby when
gas under pressure is delivered to the diffuser means, the membrane
distends and moves away from the backing surface but with the stop
means holding the member spaced generally adjacent to the backing
surface for flow of gas through the distended portion of the
membrane.
2. The diffuser means set forth in claim 1 wherein the movable
valve member is formed of fluid impermeable material and is carried
on the membrane.
3. The diffuser set forth in claim 1 wherein the movable valve
member is integrally formed in the membrane.
4. The diffuser set forth in claim 1 wherein the backing surface of
the .[.diffuser.]. .Iadd.body member .Iaddend.is generally planar
and the .[.member.]. .Iadd.membrane .Iaddend.is secured to the
.[.diffuser.]. .Iadd.body member .Iaddend.around the periphery of
the backing surface.
5. The diffuser set forth in claim 4 wherein the backing surface
and the distended portion of the membrane are of generally disc
shaped configuration.
6. The diffuser set forth in claim 1 wherein the membrane has a
plurality of small pores formed therein which expand in size when
the membrane is distended by the gas under pressure for flow of gas
therethrough and which close when the membrane collapses against
the backing surface for blocking flow of liquid therethrough.
.Iadd.
7. Diffuser means for use in an aeration basin for introducing gas
in the form of bubbles into liquid held in the basin, said diffuser
means comprising:
a body member having a backing surface and passaging in the body
member extending from a gas inlet positioned to receive gas under
pressure from a source thereof to an outlet at the backing surface
for delivery of the gas under pressure thereto;
a flexible, gas-permeable membrane covering the backing surface and
secured generally along the periphery of the membrane to the body
member in sealing relation, the membrane being positioned to
distend and move away from the backing surface upon the delivery of
gas under pressure to the diffuser, with the gas flowing through
the distended portion of the membrane and into the liquid in the
form of relatively small gas bubbles, and being positioned to
collapse into engagement with the backing member when gas under
pressure is not delivered to the diffuser;
and check valve means comprising movable valve member means movable
with the membrane and a valve seat on the body member at said
outlet, the movable valve member means being moved away from the
valve seat along with the membrane when gas under pressure is
delivered to the diffuser to open the check valve for allowing the
gas to enter the space between the member and the backing surface,
and the movable valve member means being moved into sealing
relationship with the valve seat to close the check valve when gas
under pressure is no longer delivered, for blocking flow of liquid
into the passaging in the diffuser means; and
stop means comprising interengageable means on the body member and
the member generally at central portions thereof for holding the
central portion of the member generally adjacent to the central
portion of the backing surface, whereby when gas under pressure is
delivered to the diffuser means, the membrane distends, with
portions of the membrane spaced outwardly of said central portion
moving away from the backing surface but with the central portion
of the membrane remaining held closely adjacent to the central
portion of the backing surface by said stop means. .Iadd.
8. The diffuser means of claim 7, wherein said movable valve member
means is formed as an integral portion of said membrane. .Iadd.
9. The diffuser means of claim 8, wherein the movable valve member
means is formed of material which is fluid-impermeable when
pressurized gas is applied. .Iadd.
10. The diffuser of claim 7, wherein said movable valve member
means is a separate component from said membrane mounted to said
membrane. .Iadd.11. The diffuser of claim 7, wherein said movable
valve member means is distinct from said membrane and is at least
in part embedded in said membrane. .Iadd.12. The diffuser of claim
7, wherein the backing surface of the body member is generally
planar and the membrane is secured to the body member around the
periphery of the backing surface. .Iadd.13. The diffuser of claim
12, wherein the backing surface and the distended portion of the
membrane are of generally disc-shaped configuration. .Iadd.14. The
diffuser of claim 7, wherein at least the portions of the membrane
spaced outwardly of said central portion thereof have a plurality
of small pores formed therein which expand in size when the
membrane is distended by the gas under pressure for flow of gas
therethrough and which close when the membrane collapses against
the backing surface for blocking flow of liquid therethrough.
.Iadd.15. The diffuser of claim 7, wherein said interengageable
means is secured to the membrane generally at a central portion
thereof for limiting movement of said central portion of the
membrane away from the backing surface to a predetermined position
spaced apart from yet being generally adjacent to the backing
surface. .Iadd.16. The apparatus of claim 7, wherein said stop
means, when gas under pressure is supplied, holds said central
portion of said membrane against said backing surface.
Description
BACKGROUND OF THE INVENTION
This invention relates to a diffuser for introducing gas in the
form of bubbles into liquid held in an aeration basin, and more
particular to so-called "disc" type diffusers having a bubble
generating member of generally disc shape.
Diffusers for aeration basins holding a bio-degradeable liquid such
as sewage are typically mounted at regularly spaced intervals on a
grid of piping covering the bottom of the aeration basin. The
piping delivers gas (usually air) under pressure to the diffusers,
and each of the diffusers in turn generate relatively small bubbles
in the liquid. Thus, air is delivered to the liquid in the basin in
the form of small bubbles throughout the extent of the basin to
enhance the transfer of oxygen to the liquid for faster oxidation
treatment of the liquid.
Conventional "disc" type diffusers comprise a body member mounted
on the piping and a disc of gas permeable ceramic material secured
to the body member. The body member has a gas inlet at the bottom
thereof adapted to receive air under pressure from the piping and a
generally circular open top in flow communication with the gas
inlet. The disc of ceramic material is fitted over the top of the
body member in sealing relationship therewith. When air pressure is
delivered to the diffuser, it flows into the inlet, up toward the
top of the body member and out through the gas permeable ceramic
disc into the sewage in the form of bubbles. Flow of liquid back
down into the diffuser, when air under pressure is not being
delivered, is blocked by the ceramic disc which is impermeable to
the flow of liquid therethrough.
A problem with the conventional "disc" type diffuser is that over
time suspended solids in the liquid being treated tend to deposit
on the ceramic disc and block the gas passages or pores in the
disc. This blockage tends to reduce the flow rate of air through
the disc thereby reducing the amount of oxygen delivered to the
liquid for treating the liquid. In the extreme, this blockage stops
all flow of gas through the ceramic disc, thus rendering the
diffuser incapable of performing its intended purpose. In addition,
with the ceramic disc completely blocked, the air pressure may
become so great as to cause the disc to be blown off the body
member, thus also rendering the diffuser incapable of performing
its intended purpose. In addition, the latter occurence allows
liquid to enter the piping system, which may damage it.
SUMMARY OF THE INVENTION
Among the several objects of this invention may be noted the
provision of a diffuser having a bubble generation membrane which
remains free of deposits of solids in the liquid being treated
which could block the pores in the membrane; the provision of such
a membrane which has pores therein which open only when air under
pressure is delivered to the diffuser and close when air under
pressure is not delivered to the diffuser for keeping suspended
solids from entering the pores; and the provision of such a
diffuser which has a check valve associated therewith for
positively blocking flow of liquid into the piping.
The diffuser means of this invention comprises a body member having
a backing surface and passaging in the body member extending from a
gas inlet adapted to receive gas under pressure from a source
thereof to an outlet at the backing surface for delivery of the gas
under pressure thereto. The diffuser further includes a flexible,
gas permeable membrane covering the backing surface and secured
generally along the periphery of the membrane to the body member in
sealing relation, the membrane being adapted to distend and move
away from the backing surface upon the delivery of gas under
pressure to the diffuser, with the gas flowing through the
distended portion of the membrane and into the liquid in the form
of relatively small gas bubbles, and being adapted to collapse into
engagement with the backing member when gas under pressure is not
delivered to the diffuser. The diffuser also has check valve means
comprising a movable valve member on the membrane and a valve seat
on the body member at said outlet, the movable valve member being
moved away from the valve seat along with the membrane when air
under pressure is delivered to the diffuser to open the check valve
for allowing the gas to enter the space between the member and the
backing surface, and the movable valve member being moved into
seating relationship with the valve seat to close the check valve
when gas under pressure is no longer delivered, for blocking flow
of liquid into the passaging in the diffuser.
Other objects and features will be in part apparent and in part
pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical central section of a first embodiment of the
diffuser means of this invention; and
FIG. 2 is a vertical central section of a second embodiment of the
diffuser means.
Corresponding reference characters indicate corresponding parts
throughout the several views of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown a first embodiment of the
diffuser of this invention comprising a body member having a
generally planar, disc-shaped backing surface 1, and a passaging 2
extending up from a lower gas inlet 3. The gas inlet 3 is adapted
to receive a connection or fitting from piping for delivery of gas
(such as air or oxygen) under pressure from a source thereof.
A membrane 5 of gas permeable, elastic material is stretched under
light tension over the backing surface. The periphery of the
membrane is secured to the rim of the body member in sealing
relationship by hoop band 6. To ensure a tight fit of the membrane
or the body member, the edges of the membrane may be provided with
a thickened edge margin (not shown) engageable by the band.
The membrane material is an elastomeric material which does not
react chemically with the liquid being treated and is resistant to
the growth of micro organisms thereon. The membrane has been
perforated with a large number of relatively small slots or pores.
With the membrane in an untensioned or slightly tensioned condition
these slots are closed and thus block flow of either gas or liquid
therethrough. However, when the membrane is distended (highly
tensioned) upon the delivery of gas under pressure to the diffuser,
the slots open into large pores for relatively high flow rates of
gas therethrough.
While the closure of the pores is generally effective to block flow
of liquid back into the diffuser, when air under pressure is not
delivered to the diffuser, check valve means is provided to
positively block such flow of liquid. The movable member of the
check valve comprises a disc 9 in axial alignment with but of
larger diameter than the mouth of the inlet in the backing surface
1, which serves as the valve seat of the check valve. The disc 9 is
secured to the membrane by means of a bolt 7 extending through the
disc, and threaded ring 8 and nut 10.
As shown in FIG. 1, stop means generally at a central portion of
the membrane holds this portion of the membrane generally adjacent
the backing surface of the body member when air under pressure is
delivered to the diffuser. The stop means includes interengageable
means, such as the head of the bolt 7 and an abutment member 4 in
the passaging 2 in the body member, enabling movement of the
central portion of the membrane away from the backing surface
within a predetermined range of distances.
In the operation of the diffuser, when gas under pressure is
delivered to the diffuser, the air causes the membrane to distend
and move away from the backing surface to the extent allowed by the
stop. As the membrane distends, the pores or slots open thereby
allowing the air to flow into the liquid in the form of small
bubbles emanating over the entire surface of the distended portion
of the membrane. When air under pressure is no longer provided, the
membrane collapses into engagement with the backing surface and the
pores or slots close to block flow of liquid into the diffuser. The
check valve thus provides positive blockage of liquid flow into the
diffuser
Referring to FIG. 2, there is generally shown a second embodiment
of the diffuser which is similar to the first except the numerous
elements forming the movable valve member of the check valve and
stop means or the membrane have been replaced by a single member 11
having a head integrally formed in the membrane. As with the first
embodiment, the portion of the membrane beneath the movable valve
member is the element engageable with the valve seat.
In view of the above, it will be seen that the several objects of
the invention are achieved and other advantageous results
attained.
As various changes could be made in the above constructions without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
* * * * *