Device for irradiating fluids

Abstract

A housing surrounds an elongated ultraviolet lamp and forms therewith a closed annular space to confine fluid passage means for fluids to be irradiated. The passage means surrounds the ultraviolet lamp and has relatively thin flattened passage runs that either encircle the lamp or extend longitudinally of the lamp. The passage means may provide a plurality of separate paths for sterilization of a plurality of fluid streams to be treated simultaneously and different fluid streams may be treated primarily by different wave lengths. The passage runs may be formed by thin walled resilient plastic tubing which may expand under internal fluid pressure into intimate contact with the lamp. The rays directed outwardly through the thin fluid streams may be reflected back through the thin fluid streams for greater irradiation efficiency.

Description

BACKGROUND OF THE INVENTION

Ultraviolet ray generators such as conventional ultraviolet lamps are commonly employed to irradiate various fluids including natural source waters, conditioned waters, waste waters, sugar solutions, blood plasma, food substances, and various gaseous fluids.

Although many different wave lengths of radiant energy may be employed for various desired effects, the most common applications utilize predominantly 2537 Angstrom wave lengths and 1849 Angstrom wave lengths. The 2537 Angstrom radiation known as the germicidal wave length effectively destroys organisms contained a fluid and the 1849 Angstrom radiation which is generated simultaneously by the same source may be utilized to produce oxidizing effects including the formation of ozone in oxygen gas mixtures and the formation of hydrogen peroxide in water or water mixtures. The ozone and hydrogen peroxide destroy organisms, bad tastes and odors by oxidation.

The present invention relates to a particular type of such an apparatus in which the wall of an elongated casing or housing surrounds an elongated radiant source and forms therewith an elongated annular space through which fluid flows that is to be irradiated. Prior art disclosures of this general type are exemplified by the Linker U.S. Pat. No. 1,079,503 and the Ultradynamics Corporation U.S. Pat. No. 3,182,193.

In the Linker disclosure the fluid to be treated first passes through a tube inside the ultraviolet lamp and then passes through an annular space or chamber that is formed by a casing wall that surrounds the ultraviolet lamp. The annular space around the ultraviolet lamp serves as a single passageway extending longitudinally of the lamp.

In the Ultradynamics Corporation disclosure a single stream of the fluid that is to be irradiated flows through an elongated annular space that is formed by an outer casing wall and an inner quartz tube that surrounds the ultraviolet lamp. Ring-shaped baffles in the annular space encourage turbulence in the relatively thick annular fluid stream to encourage contact between the flowing fluid and the inner quartz tube that surrounds the ultraviolet lamp.

The present invention is directed to a number of featuers and improvements for more effective utilization of the annular space or chamber that surrounds the ultraviolet lamp in an irradiating device of this general type.

SUMMARY OF THE INVENTION

Various objects of various embodiments of the invention include: to provide an effective safeguard against contamination of irradiated fluid caused by structural failure of the transparent envelope of an ultraviolet lamp; to provide flattened fluid streams for reduced thickness in the direction of radiation; to drive the fluid in the flattened streams at high velocity to create turbulence for increased irradiation efficiency; to provide an arrangement whereby a single ultraviolet source may irradiate a plurality of different fluid streams simultaneously; to provide fluid passages that have relatively thin radiation-transmitting walls and yet are capable of confining fluid streams under relatively high pressure; to provide a construction in which tubular passages with relatively thin plastic radiation-transmitting walls are effectively confined to support the tube walls and thus permit the use of relatively thin plastic passage walls with consequent reduction of the radiant energy that is absorbed by the passage walls; to provide such an arrangement in which the fluid passages with thin flexible plastic walls are confined in mutual contact for mutual reinforcement; to provide such an arrangement in which flattened fluid passages with thin flexible plastic walls may bear under internal fluid pressure against the enclosed ultraviolet lamp for mutual support; to provide such an arrangement in which relatively flattened streams of fluid are confined by relatively thin walls for maximum irradiation efficiency; to provide such an arrangement in which the flexible fluid passages make pressure contact with the envelope of the ultraviolet lamp for mutual support with the flexible passages capable of relaxing under temporarily reduced pressure to permit one ultraviolet lamp to be substituted for another; to provide maximum utilization of the radiation capability of a radiant source by completely surrounding the source with flattened streams of fluid that is to be irradiated; to provide reflector means to cause radiation that passes through a stream of fluid to be reflected back through the stream of fluid for greater efficiency; and to provide an exceptionally compact device of this general character that operates at high efficiency for processing a relatively large volume of fluid in a relativey brief period of exposure of the fluid to irradiation.

In one embodiment of the invention the passage means for the fluid to be irradiated is confined in an annular space of relatively small radial dimension and the fluid flows through runs or convolutions of the passage means which helically encircle the ultraviolet lamp for maximim utilization of the irradiative surface of the lamp. The helical passages may form a plurality of different flow paths for irradiation of different fluid with the different fluids effectively isolated from each other. A feature of the invention is that the helical passages are flattened for relatively thin dimension as measured radially of the ultraviolet lamp. With the runs or convolutions of the fluid passage means having plastic walls, the fluid passage means may be normally under relatively low internal fluid pressure and spaced radially outwardly from the encompassed ultraviolet lamp to provide a thin annular space intimately enclosing the lamp for circulation through the annular space of a fluid that is different from the fluid in the plastic tubing. On the other hand, with the fluid passage means under relatively high pressure, the plastic walls are in pressure contact directly with the ultraviolet lamp with no intervening annular space.

Suitable reflecting surfaces may be provided to intercept the radiation after it passes through the thin streams of fluid to reflect the radiation back through the same streams. The reflecting surface may be the inner circumferential surface of a cylindrical housing wall that forms the outer boundary of the annular space that confines the fluid passages. Or instead, radially inward reflection of the radiation may be provided by reflecting surfaces on the thin walls of the fluid passages. Thus, reflective coatings may be deposited on the outer surfaces of the outer walls of the fluid passages, or may be deposited on the inner surfaces of the outer walls of the fluid passages, or may be incorporated into the outer walls of the fluid passages between the outer and inner surfaces of the outer walls.

In some embodiments of the invention wherein helical runs of one or more passages encompass an elongated ultraviolet lamp, helical ribs extending radially inwardly from the outer housing wall serve as spacers between the helical runs of the flexible fluid passages to resist surging pressures and forces that are created in the operation of the device. In one embodiment of the invention the outer cylindrical wall of the device is provided with cooling fins.

In one embodiment of the invention the fluid passage means that encompasses the elongated ultraviolet lamp is formed with convolutions or runs that extend longitudinally of the lamp in side-by-side relationship.

A feature of one embodiment of the invention is that the runs or convolutions of the passage means that encompasses the ultraviolet lamp are not formed by tubes but are formed by ribs that extend radially inwardly from the outer housing to the peripheral surface of the ultraviolet lamp. The advantage of this arrangement is that radiation from the ultraviolet lamp enters directly into the flowing fluid instead of entering the flowing fluid through a passage wall that absorbs a certain amount of the radiant energy.

One feature of the preferred practice of the invention is the concept of providing a housing structure that completely encloses an elongated ultraviolet lamp as well as fluid passages that surround the lamp, which housing structure comprises a previously mentioned cylindrical housing wall and housing blocks at the two opposite ends of the cylindrical wall. Inlets and outlets for fluid to be irradiated are incorporated in the two housing blocks and terminals for connecting the ultraviolet lamp to an external EMF source are also provided by the housing blocks. Suitable elastic sealing rings embrace the opposite ends of the elongated ultraviolet lamp to seal off the two ends of the annular space that confines the fluid passages. The various features and advantages of the invention may be understood from the following detailed description together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is a side elevation of a selected embodiment of the invention;

FIG. 2 is a broken longitudinal view of the same embodiment;

Fig. 3 is a fragmentary sectional view taken along the staggered line 3--3 of FIG. 2;

FIG. 4 is a fragmentary longitudinal sectional view of a second embodiment of the invention;

FIG. 5 is a similar view of a third embodiment;

FIG. 6 is a fragmentary longitudinal sectional view of a fourth embodiment of the invention;

FIG. 7 is a transverse sectional view of a fifth embodiment of the invention wherein the runs or convolutions of the passage means extend longitudinally of the ultraviolet lamp that they enclose;

FIG. 8 is a longitudinal section taken as indicated by the line 8--8 of FIG. 7 showing the longitudinal configuration of the passage convolutions;

FIG. 9 is a radial sectional view showing how the inner surfaces of the outer walls of flexible passages for the fluids to be irradiated may be provided with reflective coatings whereby radiation passing through a thin fluid stream may be reflected back through the stream;

FIG. 10 is a similar sectional view showing how such a reflecting surface for the same purpose may be provided by a coating that is deposited on the outer surface of the outer wall of the flexible passage; and

FIG. 11 is a further similar sectional view showing how a reflective surface for the same purpose may be encapsulated in the outer walls of the flexible fluid conducting passages.

DESCRIPTION OF THE VARIOUS EMBODIMENTS OF THE INVENTION

In the first embodiment of the invention shown in FIGS. 1-3, an ultraviolet lamp 10 is enclosed by a housing that comprises an aluminum housing cylinder 12, a pair of end blocks 14 and 15 of suitable plastic material in which the ends of the housing cylinder are embedded, and a pair of opposite sheet metal end caps 16 and 17 which are mounted on the corresponding end blocks by suitable screws 18. Electric wires 20 from an emf source are connected to sockets 22 at each end of the housing, which sockets receive terminal prongs 24 at the opposite ends of the lamp 10.

The inside diameter of the housing cylinder 12 is greater than the outside diameter of the lamp 10 so that the housing cylinder cooperates with the lamp to form a longitudinal annular space around the lamp through which liquid may flow for irradiation by the lamp. The opposite ends of this longitudinal annular space are preferably sealed off by corresponding O-rings 26 which embrace the ends of the lamp and are confined under pressure by inner transverse walls 28 of the two end caps 16 and 17. It is apparent that the two end caps 16 and 17 may be removed by loosening of the screws 18 to permit the lamp 10 to be withdrawn from the housing for replacement.

In this first embodiment of the invention, passage means for fluid flow through the longitudinal annular space comprises two tubes 30 and 32 made of a suitable flexible or resilient material that is transparent to the radiation from the lamp 10. A suitable material for the tubes 30 and 32 is sold under the trademark TEFLON which is known technically as FEP (fluorinated ethylene propylene). An important advantage of this plastic is that it is inert and has non-stick properties such that no film builds up on the tubes 30 and 32 during use. It is to be noted that the tubes 30 and 32 are of flattened cross sectional configuration to occupy the longitudinal annular space, the minimum cross sectional dimension of the tubes being radially of the lamp 10 to minimize the distance through the flowing fluid that the radiation must travel and thus minimize loss of the radiant energy by absorption in the fluid.

The tube 30 is wound helically in the longitudinal annular space with one end 34 of the tube embedded in end block 14 in communication with an inlet passsage 35 which is connected by a suitable fitting 36 to an exterior conduit system (not shown). In like manner the second end 38 of the tube 30 is connected to an outlet passage 40 in the end block 15 for outflow through a conduit fitting 42.

In the same manner as the first tube 30, the second tube 32 is wound helically in the longitudinal annular space with one end of the tube in communication with a conduit fitting 36a through an inlet passage 35a in the end block 14, and with the second end of the tube communicating with a conduit fitting 42a through an outlet passage 40a in the end block 15. Thus, the passage means for fluid flow through the longitudinal annular space comprises two passages each of which has helical runs or convolutions in the longitudinal annular space, the helical runs being in side-by-side contact with the helical runs of one passage lying between helical runs of the other passage.

In FIG. 2 the fluid that flows through the two tubes 30 and 32 is at relatively low pressure and the inner circumferential surfaces of the tubes are spaced appreciably radially outwardly from the peripheral surface of the lamp 10 to form in the annular space between the lamp and the housing cylinder a thin inner annular space 44. Means to cause a third fluid to flow through this thin inner annular space 44 includes an inlet bore 45 in the end block 14 connected by a fitting 46 to an exterior conduit 48 and a similar outlet bore 50 in the end block 15 connected by a fitting 52 to an outflow conduit 54.

By virtue of the described arrangement three different fluids may be circulated simultaneously through the longitudinal annular space for simultaneous irradiation by the lamp 10. For example, the plastic tubes 30 and 32 may carry two different liquids for irradiation primarily by the 2537 Angstrom wave length of the radiant energy and an oxygen mixture such as air may flow through the inner annular space 44 for the formation of ozone therein by the 1849 Angstrom wave length of the radiant energy. To give another example, an aqueous mixture may flow through the inner annular space 44 for the formation of hydrogen peroxide therein by the shorter wave length of the radiant energy.

In another mode of operation of the embodiment shown in FIGS. 1-3, fluid flow through the inner annular space 44 is omitted and instead fluid flows through the plastic tubes 30 and 32 with the spiral runs of the tubes in pressure contact with both the outer housing cylinder 12 and the inner lamp 10 and with the sides of the helical turns of the tube 30 in mutual pressure contact with the sides of the helical turns of the plastic tube 32. An important advantage of this arrangement is that since the walls of the plastic tubes 30 and 32 are supported, the walls may be exceedingly thin even though the internal fluid pressure is relatively high and, of course, the thinner the walls of the two spiral tubes the less the amount of absorption of the radiant energy by the walls. The mutually contacting side walls of the two tubes 30 and 32 are supported by each other and it is to be noted that the fluid pressures on the opposite sides of each pair of contacting walls are balanced so that the pressure drop across each pair of mutually contacting side walls may be practically zero.

Another advantage of this second mode of the embodiment shown in FIG. 1 is that with the two spiral plastic tubes 30 and 32 in pressure contact both with the housing cylinder 12 and with the periphery of the lamp 10, the plastic tubes support the lamp against vibration and shock. Another advantage is that the spiral runs of the two plastic tubes embrace the lamp 10 under pressure to immobilize the lamp in the housing and to protect the immobilized lamp. Simply reducing the fluid pressure in the two helical tubes 30 and 32 causes the tubes to relax and thus free the lamp 10 for removal when desired.

Another advantage is that with the plastic tubes 30 and 32 of flat cross-sectional configuration, the fluids may be forced through the two tubes under high pressure at high velocity to create active turbulence in the flowing fluids. Such turbulence tends to cause all portions of the flowing liquid to make contact at one time or another with the inner walls of the spiral turns where the radiant energy is at maximum intensity.

An important feature of the invention is the concept of providing reflecting surfaces to intercept the radiation after the radiation passes through the fluid, the radiation being thus reflected back through the fluid for increased irradiation efficiency. In this regard, the provision of a housing cylinder 12 made of aluminum is advantageous not only because of the low cost and high heat conduction of aluminum, but also because an aluminum surface, and especially a polished aluminum surface, is a highly efficient reflector of radiant energy of short wave lengths. Thus, the inner circumferential surface of the housing cylinder 12 reflects the radiant energy back through the plastic tubes 30 and 32.

If desired, the reflecting surfaces may be incorporated in the structure of the flattened plastic tubes 30 and 32. For example, FIG. 9 indicates how a reflective coating 55 may be deposited on the inner surfaces of the outer walls of the helical runs of the tubes 30 and 32. Thus, the radiant energy is reflected back without absorption by the outer walls of the plastic tubes. As another example, FIG. 10 shows how reflective coatings 56 may be deposited on the outer walls of the helical turns of the plastic tubes 30 and 32. As a still further example, FIG. 11 shows a reflective surface 57 encapsulated in the outer walls of the flexible fluid conductors such as 30 and 32. This can be accomplished by forming the fluid conductors from laminated films having the reflectors sandwiched therebetween. The reflective surfaces may advantageously be made of magnesium oxide which reflects the 2537 Angstrom radiation more effectively than aluminum.

In the modification of the invention illustrated by FIG. 4, two flattened plastic tubes 60 and 62 are wound helically in side-by-side relationship in the longitudinal annular space surrounding the lamp 10, but in this instance the successive helical turns of the two tubes are separated by helical ribs 64 that extend inwardly from the housing cylinder 12a. The helical ribs 64 have utility in resisting surges of fluid pressure and other forces. A further feature of the construction shown in FIG. 4 is that the housing cylinder 12a is provided with external cooling fins 65.

The construction shown in FIG. 5 differs from the construction shown in FIGS. 2 and 4 in that a single helically wound plastic tube 66 instead of two separate plastic tubes occupies the elongated annular space around the lamp 10. In FIG. 5 the housing cylinder 12b is formed with inner helical ribs 68 that have the same purpose as the helical ribs 64 in FIG. 4. In FIG. 5, however, the housing cylinder 12b comprises a helically wound band 70 with the ribs 68 projecting inwardly from the helical band.

The embodiment of the invention illustrated by FIG. 6 is largely similar to the first embodiment as indicated by the use of similar reference numerals to indicate similar parts. A flattened plastic tube 30a is helically wound in the longitudinal annular space around the lamp 10 in the same manner as the previously mentioned plastic tube 30, but a second plastic tube is omitted so that a second helical passage 72 is created in the longitudinal annular space with the helical turns of the passage 72 alternating with the helical turns of the flattened plastic tube 30a.

The housing cylinder 12c is formed with a pair of inner helical ribs 74 which not only confine the helical turns of the plastic tube 30a, but also serve as opposite side walls for the helical passage 72. In the construction shown the helical ribs 74 make contact with the periphery of the lamp 10 and for this purpose a thin layer 75 of a suitable resilient sealing material may be provided on the inner circumferential edges of the helical ribs. A suitable silicone may be employed for this purpose. One end of the helical passage 72 communicates with an inlet passage 76 in the end block 14a that leads to a conduit fitting 78 and, in like manner, the second end of the helical passage 72 is in communication with a conduit fitting (not shown) in the second end block of the housing.

An important advantage of the construction shown in FIG. 6 is that the fluid in the helical passage 72 is in direct contact with the outer circumferential surface of the lamp 10, no radiant energy being lost by absorption in a plastic wall between the flowing fluid and the lamp. The inner surface of the housing cylinder 12c is a reflecting surface to increase the effectiveness of the radiant energy.

In the modification of the invention illustrated by FIGS. 7 and 8, the runs or convolutions of a single fluid passage of the device extent longitudinally of the lamp instead of helically of the lamp, the runs being crowded together as shown for full utilization of the circumferential surface of the lamp. The single fluid passage 80 of this embodiment is formed in part by longitudinally extending flattened plastic tubes 82 and in part by U-shaped passages 84 in the two housing end blocks 14b and 15b respectively. As may be seen in FIG. 8 the U-shaped passages 84 interconnect the ends of the contiguous plastic tubes 82 to provide a single fluid passage through the device. Preferably, the inner surface of the housing cylinder 12d is polished for radially inward reflection of the radiant energy.

In all the embodiments of the invention the fluid to be treated is in a region of maximum intensity of radiant energy with minimum travel of the radiant energy required to reach all parts of the flowing fluid. With the addition of reflecting surfaces the radiant energy is utilized with maximum effectiveness.

It is to be noted that although the convolutions of the passage means in FIGS. 2, 4, 5 and 6 extend circumferentially of the elongated lamp and the convolutions in FIG. 8 extend longitudinally of the lamp, in both instances the convolutions are side-by-side and the overall configuration of the passage means is annular and completely surrounds or encases the lamp for full utilization of the available radiant surface of the lamp.

An important feature of the embodiments of the invention shown in FIGS. 2, 4, 5 and 7 is that the flowing fluid that is to be treated by radiant energy is completely encased in plastic walls. If the ultraviolet lamp 10 is cracked or broken there is no danger of contamination of the flowing fluid.

My description if specific detail of the selected embodiments of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

Claims

I claim:

1. In a device for radiant treatment of flowing fluid, the combination of:

an elongated lamp providing a source of radiant energy and having an envelope wall; and

passage means for flow therethrough of fluids to be treated by the radiant energy;

said passage means comprising a plurality of tubes of flexible non-metallic material having a unitary wall structure transparent to said radiant energy in side-by-side relationship each being of substantially smaller cross sectional area than the radiant source;

said tubes being positioned to jointly provide an overall configuration of an annulus surrounding and substantially completely encasing the envelope wall of said radiant source.

2. The combination as set forth in claim 1 in which each of said runs encircle in close proximity to the envelope wall of the radiant source.

3. A combination as set forth in claim 2 in which said tubes provide a plurality of independent helical flow paths through said annulus for conveying fluids through the annulus simultaneously.

4. A combination as set forth in claim 1 in which said tubes have flexible pressure-responsive walls,

said tubes being of flattened cross sectional configuration with their minimum cross sectional dimensions radially of said source,

said tubes normally functioning under relatively high fluid pressure in pressure contact with the radiant source,

said tubes being capable of relaxing in response to lowered fluid pressure therein to release the pressure of the tubes against the source.

5. A combination as set forth in claim 1 in which each of said runs extends in a direction parallel to the axis of the radiant source.

6. The combination as set forth in claim 5 in which the tubes coact to form a single flow passage having alternately reversed flow portions extending between opposite end portions of the radiant source.

7. The combination as set forth in claim 1 in which said tubes are formed of fluorinated ethylene propylene.

8. A combination as set forth in claim 1 in which said tubes have plastic pressure-responsive walls;

and in which the tubes are surrounded by adjacent housing structure in pressure contact therewith whereby the adjacent housing structure reinforces the plastic walls.

9. A combination as set forth in claim 8 in which said tubes are confined side-by-side in pressure contact with each other for reinforcement against their internal pressures.

10. A combination as set forth in claim 1,

which includes a separate housing enclosing the tubes;

in which helical ribs cooperate with the envelope wall of the radiant source and said housing to form helical spaces between the source and the housing;

and in which the fluid flows through said helical spaces.

11. A combination as set forth in claim 10 in which the tubes are helical and have flexible pressure-responsive plastic walls;

and in which said tubes occupy said helical spaces.

12. A combination as set forth in claim 1 which includes reflector means to intercept the radiant energy from said source after the radiant energy passes through said tubes, said reflector means serving to reflect the radiation inwardly through the tubes towards the radiant source.

13. A combination as set forth in claim 12 in which said relector means is the inner circumferential surface of a housing surrounding the tubes.

14. A combination as set forth in claim 13 in which said inner circumferential surface of the housing is an aluminum surface.

15. A combination as set forth in claim 12 in which said tubes have plastic walls capable of transmitting the radiant energy;

and in which said reflector means comprises a coating of reflecting material carried by plastic walls that are on the sides of the tubes that are away from the elongated radiant source.

16. A combination as set forth in claim 1 in which said housing has external cooling fins.

17. A combination as set forth in claim 1 in which said passage runs coact with the envelope wall of said source of radiant energy to form a flow passage for the fluid to flow in direct with the envelope wall of the source of radiant energy.

18. In a device for irradiating fluids, the combination of:

an elongate tubular lamp providing a source of radiant energy; and

multiple flexible tubes for different fluids to be irradiated,

each tube extending along the lamp of said source in close proximity thereto and being conformed to the outer surface configuration of the lamp tube,

each tube being of flattened cross sectional configuration with its width a multiple times its thickness and with its thickness dimension extending radially of said source,

said multiple tubes extending over at least a major portion of the irradiating surface of said lamp.

19. In a device for irradiating fluids, the combination of:

an elongated lamp source of radiant energy having a peripheral enclosing wall;

at least one tube of flexible material extending substantially from one end to the other of said radiant source,

said tube being flattened towards said source in transverse cross section; and

housing means spaced from the enclosing wall of the radiant source with the flattened tube occupying at least the major portion of the radial dimension of the space between the enclosing wall and the housing means.

20. A combination as set forth in claim 19, wherein said housing means confines the passage means to limit expansion in cross section of the passage means in response to fluid pressure in the passage means.

21. A combination as set forth in claim 20 in which the fluid is under pressure with the flexible walls of the tube in pressure contact with both said housing and said source of radiant energy.

22. A combination as set forth in claim 19 in which a plurality of tubes extend from one end to the other of the radiant source to carry different fluids.