Title:
FLUID IRRADIATING APPARATUS USING GAMMA RAYS AND HELICAL PASSAGEWAYS
United States Patent 3602712


Abstract:
A radioactive apparatus is provided for the sterilization and treatment of liquids and especially for the sterilization and treatment of liquid waste such as sewage and industrial waste by the use of gamma radiation sources. A spiraling input chamber spirals around a center chamber having an elongated core member with a helical pipe forming a helix or coil around said hollow member in the center chamber. Liquid waste being received by the apparatus passes through the spiraling chamber into the center chamber, into and through the elongated hollow member and then through the helical pipe to an output. Gamma radiation sources are located around the helical pipe in such a manner as to provide an efficient use of the radiation sources.



Inventors:
Mann, Leland A. (Brevard, FL)
Woodbridge, David D. (Brevard, FL)
Application Number:
04/799578
Publication Date:
08/31/1971
Filing Date:
02/17/1969
Assignee:
ENERGY SYSTEMS INC.
Primary Class:
Other Classes:
250/436, 250/437, 250/438, 976/DIG.441
International Classes:
C02F1/30; G21K5/02; (IPC1-7): G21H5/00
Field of Search:
250/43,48,49,52,106,44
View Patent Images:
US Patent References:
2968734Device for the exposure of fluid to radiationJanuary 1961Yeomans
2866905Device for exposing an object to radiationDecember 1958Yeomans
2072417Method of irradiating substances with active raysMarch 1937Berndt et al.
2065055Irradiating apparatusDecember 1936Berndt et al.



Primary Examiner:
Borchelt, Archie R.
Claims:
We claim

1. An irradiator apparatus for irradiating fluids comprising in combination:

2. The apparatus according to claim 1 in which a second said passageway is connected to said center core passageway at one end portion thereof and to said output means and forming a helix around said center core.

3. The apparatus according to claim 2 in which a third passageway is connected to said center core passageway and to said input means.

4. The apparatus according to claim 3 in which said radiation sources form two circular parallel rows around said center core, one said row being located on the outside of the helix formed from said second helical passageway.

5. The apparatus according to claim 4 in which said center core passageway has baffles means located therein.

6. The apparatus according to claim 5, in which said third passageway has baffles therein.

7. The apparatus according to claim 6 in which the baffles in said center core passageway have plate baffles with openings passing therethrough alternating with solid plate baffles, said baffles being fixedly attached to said center core and to each other.

8. The apparatus according to claim 7 in which said radiation sources are elongated cylindrically shaped.

9. The apparatus according to claim 8 in which said gamma radiation sources are cobalt 60.

10. The apparatus according to claim 9, in which said third passageway is a spiralling helical pipe.

11. The apparatus according to claim 10, in which said radiation sources are contained in radiation-holding means adapted to be hung on said second helical passageway.

12. The apparatus according to claim 10, in which said radiation sources are contained in holding means attached to said center member and to the wall of said center chamber.

13. The apparatus according to claim 7, in which said gamma radiation sources are cesium 137.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to radioactive devices and particularly to radioactive devices for sterilizing and treating liquids and especially liquid waste such as sewage and industrial waste. The present irradiator provides a relatively high efficiency utilization of its gamma radiation sources to kill micro-organisms and to break down the molecular structure of components of the waste.

2. Description of the Prior Art holding pressure, to for microbiological

In the past various types of irradiators and sterilizers have been suggested for liquids and especially for disinfecting water. These prior art sterilizers frequently involved the use of heat by holding the temperature, and sometimes the pressure to an elevated degree for a predetermined length of time to obtain a substantial kill as desired of the microbiological agents in the liquid.

It has also been suggested in the past to use various types of radiation for the sterilization of liquids as well as for the sterilization of foods, drugs and the like.

The treatment of liquids by these prior art radiation means is frequently carried out by circulating the fluids through tubes having walls transparent to radiation, through which walls the radiation will pass, with the radiation source located next to the wall. Ultraviolet light has been one of the most common types of radiation use for the sterilization of liquids, and the like, and in this type of radiation as in many others, the tubes of the radiation sources may become coated with solid materials such as contaminations in the liquid, or the transparency of the liquid may be low, thus reducing the efficiency of the sterilization. This is particularly true with the use of ultraviolet radiation and the like. Such coatings and/or suspended materials have negligible effect on the effectiveness of the present invention.

Finally, it has been suggested to use radioactive isotope sources for the sterilization of liquids as well as for gases and solids. This type of sterilizer has proved advantageous over heat sterilizers because of the time saved in the rapid sterilization by radiation by avoiding the time lost during the thermodiffusion period and for other reasons. One such radiation sterilizer provides two sets of pipes alternately wrapped around a radiation source and encompassed within a lead shielding contained so that two separate liquids may be irradiated simultaneously. While this prior art device has certain advantages, it is not suitable for the treatment of liquid waste because of the small tubes used without means for keeping solid particles of contamination intermixed with the fluid. It also loses a great deal of efficiency by irradiating on only one side of the source and by useless absorption of large amounts of radiation in metal walls, and is adapted only for use with a single source. The present invention, on the other hand, provides for the irradiation of a very large volume of liquid which will normally have varying amounts of solids in various forms and sizes mixed within the liquid. It also provides a relatively high efficiency for use of the energy of the radiation source and improved flow control for the liquid passing into and out of the irradiator.

SUMMARY OF THE INVENTION

The present invention is a liquid irradiator utilizing gamma radiation sources for the sterilization and treatment of liquids, especially liquid waste such as sewage and industrial waste in which large volumes of liquids need to be treated and which liquids may commonly have various amounts and types of solid matter therein. The irradiator has a hollow center chamber and a spiralling input chamber for receiving the entering flow of liquid to spiral around the center chamber and to flow into the center chamber from the spiralling input chamber at one end thereof. The liquid then passes through the center chamber, and into an elongated core member located in the center chamber, out a pipe which is helically wrapped around the hollow member, prior to exiting from the irradiator. Gamma radiation sources are located in the center chamber and around the elongated core member and may be desirably placed in two parallel circles, one on each side of the helical exit pipe. Baffles may be appropriately located throughout the system for increasing the turbulence in the fluid to improve uniformity of radiation close to the liquid and prevent settling of any solids therein. The irradiator is of course enclosed in shielding sides which may be, for instance, concrete walls of the appropriate sides. Inlets and outlets through the shielding will be curved or bent to prevent escape of any significant quantity of the radiation, which radiation travels in a straight line and would not therefore be able to escape. For the same reason, the cover for the shielding chamber would be stepped in the usual manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of this invention will be apparent from a study of the written description and the drawings in which:

FIG. 1 is a top plan view with a portion broken away of a preferred embodiment of the present invention.

FIG. 2 is a view taken along line 2--2 of FIG. 1.

FIG. 3 is a view taken along line 3--3 of FIG. 2.

FIG. 4 shows a broken-away view of the embodiment of FIGS. 1 through 3.

FIG. 5 illustrates a baffle in the elongated core member taken along line 5--5 of FIG. 4.

FIG. 6 illustrates a second baffle of the elongated core member taken along line 6--6 of FIG. 4.

FIG. 7 shows a radiation source holder or hanger for the embodiment of FIGS. 1 through 6.

FIG. 8 is a view taken along line 8--8 of FIG. 7.

FIG. 9 illustrates a second embodiment of the present invention; and

FIG. 10 illustrates a second embodiment for a radiation-source holder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a copy illustrating the location of a loading pool 10 which is not a permanent part of the irradiator but may be used in loading and unloading the irradiator core. The sterilizer has a concrete shielding 11, an inlet pipe 12, an exit pipe 13, for the ingress and egress of liquid respectively. The sterilizer has a cover 14 which may be a shielding material such as concrete or may be a heavier material such as lead, or the like. This cover would normally be stepped, as shown by the dotted lines 15 to prevent the escape of radiation and will have brackets 16 for placing the cover on as well as moving it during loading and unloading operations.

FIG. 2 is taken along lines 1--2 of FIG. 1 and shows a cutaway of the concrete shielding 11, inlet pipe 12 and exit pipe 13. Step 15 for the cover 14 is more clearly illustrated in this view, as is bracket 16 and bracket anchors 17 which more readily adapt bracket 16 for lifting the heavy cover.

Referring now to FIG. 3, a cutaway view taken along line 3--3 of FIG. 2 is shown with the details of the core of the irradiator more clearly shown. The input 12 and exit 13 pipes can be seen with the input feeding into an inwardly spiralling chamber 20, having walls 21 and baffles 22. Chamber 20 allows the input liquid to gradually move in toward the radiation source, with the radiation getting more intense as the liquid moves through the spiralling chamber. This chamber is illustrated as circular in cross section, but could of course be oblong, square or irregular-shaped without departing from the spirit and scope of the present invention. Baffles 22 provide turbulence to improve the mixing of the liquid, to keep solid matter mixed within the liquid and to provide better flow characteristics of the liquid, as well as more uniform irradiation of the liquid. As the liquid in chamber 20 approaches the end of the spiralling chamber 23, it is forced through a passage 19 (FIG. 4) into a center chamber 18 and into an elongated member 24. Member 24 has a series of concentric alternating baffles 25 and 26, baffles 25 being connected to the side of center member 24 with openings in the center thereof. Baffles 26 on the other hand are circular members connected to baffles 25 by baffle-holding rod 29. This baffling system of intermittent baffles not only provides for turbulence and thorough mixing of solid matter in the liquid, but also forces the liquid near the walls of center member 24 at various points as it passes through, as will be described in more detail later. The liquid exits from core member 24 at 27 into a helical pipe 28 which wraps in a helix around center member 24 and exits at exit 13. Helical pipe 28 is illustrated as being circular in cross section but could, of course, be square, rectangular or any other shape without departing from the spirit and scope of this invention. The sources of gamma radiation 30 are placed in a circle around center member 24 and a second group of sources of gamma radiation sources 31 may be placed around center member 24, but further out so that they also encircle the helix formed by pipe 28. These sources of radiation 30 and 31 may be pencil-shaped, cobalt 60 or cesium 137, but it is to be understood that other shapes and sources of radiation may be used without departing from the spirit and scope of the present invention. However, the pencil or elongated cylinder shape is one form in which cobalt 60 is commercially available, thus making it a desirable source because of its availability and reasonable price in this particular shape. Radiation-source hangers 32 are adapted to have holders attached thereto which the radiation sources may be placed in. These hangers are illustrated as being hung on pipe 28, but will be described in more detail later.

Referring now to FIG. 4--a broken view taken along line 44 of FIG. 1 is shown, having input 12, exit 13, and spiralling chambers 20, with chamber wall 21. Member 24 and chamber 18 can be more clearly seen as can baffles 25 and 26, and baffle-holding rods 29. The liquid leaving chamber 20 through passageway 19 and flowing into chamber 19 will enter the top portion of member 24 and will flow therethrough in a turbulent manner because of the baffles 25 and 26, but all of the liquid will be forced near the walls of member 24, very close to radiation sources 30. Upon reaching the bottom of member 24, the liquid will be forced into pipes 28 at entrance 27 and will be circulated in a helical path between radiation sources 30 and 31, and will flow out exit 13. A set of braces 39 may be used to maintain pipe 28 at the proper angle of the desired helix. Source-hanging rods 32 with source holder 33 attached thereto and holding sources 31 and 30 may also be seen, as can shielding 11.

FIGS. 5 and 6 are taken along lines 5--5 and line 6--6 respectively of FIG. 4, and illustrate more clearly the baffles in member 24. FIG. 5 illustrates the center baffle member 26 held by holding rods 29 which are in turn connected to baffle members 25, but do not directly touch center core member 24, while FIG. 6 shows baffle plate 25 directly connected to elongated member 24 and also to baffle-holding rods 29.

FIG. 7 illustrates one type of hanger 32 for holding sources 30 and 31. The rods of hanger 32 have containers 33 connected thereto for holding the sources while a plate 35 is attached to the rods and has an aperture 36 whereby a pair of sources may be removed with a hook or other mechanical means for handling the source in a safe manner.

FIG. 8 shows a view along line 8--8 of FIG. 7 and shows a source 30, source container 33, rod 32, and shows container 33 connected to rod 32 by weld 36.

Turning now to FIG. 9, there is shown a second embodiment of the present invention in which most of the features of the invention remain the same but in which the spiralling chambers have been replaced by a large pipe and in which the source holders used are of a different type. Liquid to be irradiated is received at the input 12 through shielding 11, which as explained may be concrete but if the structure is to be beneath the earth, earth embankments would also provide adequate shielding if sufficiently thick. The liquid enters relatively large pipe 40 and proceeds in a circular manner forming first an outer and downwardly proceeding helix and then an inner upper proceeding helix in an outer section 41 separated from an inner section by wall 42. At the finish of the double helix the liquid enters an elongated center member 24 at 43. Center core 24 may be the same as described in the earlier embodiment. The liquid then proceeds through center member 24 and exits at 27 into pipe 28 which then encircles center member 24 as already described, prior to exiting at output 13. Inner source holders 44 are connected to center member 24 by brackets 45 and outer source holders 46 are connected to wall members 47 by brackets 48. They will be described in more detail in connection with FIG. 10. As can be seen at this point, entering liquid gradually proceeds towards the center core and then back through the radiation sources so that the liquid is being continuously radiated as it passes through the irradiator.

FIG. 10 shows a more detailed view of radiation holder 44 and bracket 45; radiation source 30 may also be seen, which may be an elongated cylinder-shaped source of cobalt 60, or the like, and holder 44 may have funnel-shaped opening 46 to provide for easier loading of the source 30. Since this type of holder is not readily adaptable to remove the holder, the source would normally have to be removed separately if this were required for any reason. However, it is anticipated in the present invention the entire irradiator will be loaded prior to having its concrete overhead shielding top put in place and will require no further entry until the sources must be replaced at which time the radiation source containers would be removed, reloaded and replaced.

As will be clear to those skilled in the art, an irradiator or device has been provided for irradiating liquids, especially liquid waste such as sewage effluent, and the like, and which acts to kill micro-organisms and to break down contaminants such as detergents, herbicides and pesticides. In the case of detergents, it has been found that they can be broken down whether they are biodegradable or not in most cases, thus simplifying the overall treatment process.

It is contemplated that other embodiments are within the scope of the invention and such embodiment might for instance include a pair of concentric tubes surrounding and parallel to the center member and being baffled so that liquid leaving the special chamber will pass vertically between the baffled tubes up through one and down the next. This would of course replace the helical pipe means and would include additional baffles.

This invention is not to be construed as limited to these particular forms disclosed herein since these are to be regarded as illustrative rather than restrictive.