DE7621448U1 - DEVICE FOR DISINFECTING LIQUIDS - Google Patents

Description

64/76

6/14/76 Br / dh

BBC Aktiengesellschaft Brown, Boveri & Cie., Baden (Switzerland)

Device for sterilizing liquids

The invention relates to a device for disinfecting liquids by means of ultraviolet radiation of the majority 254 nm wavelength, with a radiation source with The medium to be sterilized flows across the cylindrical boundary.

It is known that liquids with ultraviolet rays of a certain spectral composition, in particular the characteristic 25 ^ 1 nm Hg line can be effectively sterilized be able. Above all, disinfection devices equipped with conventional low-pressure UV lamps are known on the market are. Since the UV radiation output of this type of radiation source is both absolute and specific (ge

7R? 1 £ AB tone70

measure in mW / cm) is small, are either the degree of sterilization or the flow rate of the medium to be sterilized relatively low limits are set.

The preferred embodiment of UV radiation sources for Devices for disinfecting liquids is the one

with circular cylindrical delimitation, the quartz protective tube in question the medium to be sterilized flows either longitudinally or transversely. Such devices are large Number known, including mainly those with cross flow the radiation source are of interest (e.g. Oe-PS 321 829; US-PS 3,637,342; US-PS 3,837,800). The realization of disinfection devices encounters considerable structural difficulties. Among other things, it must be ensured that no Dead spaces arise in the flow pattern, which often requires additional means to increase the turbulence (e.g. CH-PS 477 for longitudinal flow in the shell space between coaxial pipes). In the practice tfsrden for TrinlcWassrentknung Durciiflussincn— genes of 5 m / h per UV lamp with a killing rate of 500 for Bacterium E. CoIi (ratio of germs before and after disinfection). This requires larger flow rates the parallel or series connection of a large number of radiation sources (e.g. US Pat. No. 3,634,025).

The known disinfection devices use low pressure

7621448 05/18/78

> 1

SH / jS

UV radiation sources of a conventional type, which in the case of high flow rates and a wide disinfection wheel complicated, complex and expensive devices result. This is due to the low standard output of conventional low-pressure emitters together. Furthermore, the complicated periodic cleaning of the quartz protective tubes that cannot be carried out immediately is all the more important more important, the greater their number and the more complex the structure of the device, which is often evident from the above can not circumvent fluidic reasons. The high space requirement and the mostly necessary diversions in the wiring harness of the medium to be disinfected make it difficult to install such known devices. The power per UV lamp can be increased by using high-pressure mercury radiation sources. However, such emitters have one compared to low-pressure units significantly lower efficiency based on the intensity of effective UV radiation and pollute the medium to be sterilized by their heating possibly in an inadmissible manner »The proportionate The short service life of high-pressure lamps poses further obstacles to their use.

The invention has the object to provide a device for disinfecting liquids, the large at high kill rate flow rates permitted to process to be sterilized medium per unit radiation of _s single

7621448 I8.0E28

multiple constructive structure, high operational safety and \

has a low price and allows space-saving, simple 1 installation and easy cleaning. |

According to the invention, this is achieved in that as a line?

a pipe is provided for the medium to be sterilized, I

that of at least one cylindrical quartz protective tube through- '. ■

is penetrated, which is a low pressure f

High-current mercury vapor discharge tube with a discharge §

2 I.

current density of at least ΙΑ / cm and a mercury vapor pressure of at most 0.5 Torr, such that said
Medium flows around the quartz protection tube.

Radiation sources of the type mentioned above are known
(e.g. DT-OS 2U 12 997 of the applicant).

Further details of the invention emerge from the following Exemplary embodiments explained in more detail by figures

It shows:

Fig. 1 Elevation and floor plan of a basic type of sterilization
device with regard to its relative position in the wiring harness,

Fig. 2 is a schematic representation of the device
constituent basic elements and their geometric
Relationships,

Fig. 3 ....... ·· «« »; "" I. "> 5i
... »·. · · Ca» f V - ⁵ "64/76 a longitudinal section through the device iait for flow Fig. 1} muiigsrichtung leaning quartz protective tube of the Radiation source, Fig. 5 partial cross-section, partial view in flow direction of the device according to Fig. 3, a longitudinal section through the device with Fig. 6th in the direction of the vertical quartz protection tube Radiation source, Fig. 7th partial cross-section, partial view in flow direction of the device according to Fig. 5, Fig. 8th partial cross-section, partial view in flow direction of a version with oval conduit pipe, partial cross-section, partial view in flow Fig. 9 direction of a version with a rectangular pipe pipe, the outline of a disinfection device with three each Fig. 10 quartz protective tubes containing a radiation source V in relation to their relative position in the cable harness, the relative kill rate as a function of the flow rate r amount for drinking water with a penetration depth for / UV radiation of 15 cm. 1
/ 7621448 05/18/78

* Λ

Fig. 1 shows the disinfection device in its relative position to the cable harness. The medium 1 to be sterilized is fed to the device through the incoming line 2, flows through the line pipe 3 of the device and leaves the same through the outgoing line 4. The line pipe 3 is connected to the incoming and outgoing line with pipe flanges 5 in a conventional manner. On its way through the device, the medium 1 flows around the quartz protective tube 6 containing the UV radiation source in such a way that the flow runs essentially transversely to its longitudinal axis. 7 represents the heat sink of the radiation source, not shown here, housed inside the quartz protective tube. The conduit 3 has an effective length L and, in the case of a circular cross section, an inner diameter D, whereas the outer diameter of the quartz protective tube is d. This results in the relationship for the maximum half the width of the cross section

Δ-

D-d

In order to achieve optimal utilization of the UV radiation, certain geometrical relationships of the dimensions D, d and L are observed. See FIG. 2. From this basic form of the disinfection device shown in FIG the various embodiments depicted in the figures to 9 are described in more detail. The cross-section of the

7621448 05/18/78

Line pipe 3 also have a shape deviating from the Xreisform. The quartz protective tube 6 can also be crooked At an angle to the direction of flow.

The geometrical relationships of the device are shown schematically in FIG. The medium 1 to be sterilized flows

with flow direction from left to right through the pipe

processing pipe 3 with longitudinal axis 8. The longitudinal axis 9 of the jet -I containment source quartz protective tube 6 closes with

the longitudinal axis 8 (= the direction of flow) the angle eCein, which is preferably in the range of ¹ 15-135. The execution; are approximate shapes of the mutually penetrating pipes

do not intersect on the example shown in Fig. 2: the longitudinal axes 8 and 9 limited. The latter can also

cross, i.e. stand crooked to each other. Under certain

J circumstances, e.g. when introducing or attaching Hess probes

* of observation windows in the cross section can be one of the

like asymmetrical arrangement would be desirable. The dimensioning is carried out in such a way that a UV ray of the 25 ¹ J nm Hg line exiting perpendicularly from the quartz protective tube 6 at point A or 3 with intensity I after striking the inner wall of the conduit 3 at point A ¹ or B ¹ still has an intensity of 0.2 I to 0.5 I. The absorption lengthways

the line AA ⁷ = ¹ 3B * = Δ = '^ ^SO11 - ^so 5Ο5ί to 80% loading, wear. The length L of the pipe 3 becomes more advantageous

7621448 05/18/78

• if

- 8 - * ·· * ^: 64 / 7β

Way to 1 to 3 times D dimensioned. A preferred execution is the one with L = 2D.

Figures 3 and 4 show a longitudinal and a cross section _;

or partial view of a device with pipe 3 S

with a circular cross-section. The UV = radiation source IG, preferably in a single-piston design, is coaxially enclosed by the quartz protective tube 6 with a longitudinal axis 9. In the illustrated embodiment, the longitudinal axis 9 of the quartz protective tube 6 (= longitudinal axis of the radiation source 10) forms the angle <£, with the longitudinal axis 8 of the pipe 3. The quartz protective tube 6 is held at both ends by stuffing boxes 11 and against the liquid pressure inside the Line pipe 3 sealed. 12 is a conventionally constructed and used in a known manner cleaning device consisting of one or more axially one behind the other ring-shaped or toroidal brushes, which isird by means of an operating handle 13 is operated by hand. The cleaning of the surface of the quartz tube takes place in accordance with the composition of the medium to be sterilized at periodic intervals to the deposition of solids, which diminish the effectiveness of the UV radiation, zn stop. The remaining reference symbols correspond to those of FIGS. 1 and 2.

A particularly simple design in terms of construction

7821448 05/18/78

- 9 - 64 "/ 76

5 and 6 show in longitudinal and cross-section or partial view. The reference numbers correspond to those 3 and 4. The longitudinal axis 9 of the quartz protective tube and the associated radiation source 10 is perpendicular here on the longitudinal axis 8 of the pipe 3

In FIGS. 7 and 8, two embodiments with flat conduit pipes 3 are shown. In the case of FIG. 7 it is a pipe 3 with an oval or elliptical cross-section, while FIG. 8 shows a pipe 3 with a rectangular cross-section. In the latter case, the corners of the rectangle are expediently | rounded in a suitable manner. As a determining measure for the | UV radiation now appears here as the width (= minimum inner clear width) of the conduit 3. Similarly, in the formula according to FIG. 2, the dimension "D" is replaced by the dimension "E": AA ¹ = BB '= ^ = ■ The embodiments according to FIG. 7 and FIG. 8 are particularly suitable for the disinfection of media with less penetration depth for UV radiation, eg for salt water, since they allow a more favorable utilization of the cross-section for a given flow rate. It goes without saying that the cross-sections according to FIG. 7 and FIG. 8 can also be used for embodiments according to FIG.

7621448 ii.05.78

6 *) / 7 6

For very high flow rates or media with high absorption or low penetration depth for UV radiation, in Advantageously, a series connection of several radiation sources, a maximum of four, is used. Fig. 9 shows an embodiment with a total of three radiation sources, wherein the reference numerals correspond to those of FIG.

N In FIG. 10, the relative killing rate is - - ■ - as a function of the flow rate Q (m / h) for a device according to FIG. ¹ and FIG. 6 for drinking water with a penetration depth "K = 15 cm for 25 1 J nm-Hg Radiation. The flow rate Q in m / h is plotted on the abscissa on a reciprocal scale from right to left. The ordinate has a logarithmic scale. N is the number of germs before, N the number after disinfection in relation to the Volume unit of the medium. In the present example it is Bacterium E. Coli. The penetration depth / L of the UV radiation is defined as the distance from the surface of the quartz skin 6-in which the intensity of the 254 nm radiation after passing through the Medium has sunk to the 1 / e-th part in the case of parallel radiation (e = 2.7l8), i.e. in which the radiation intensity (= radiation power / solid angle; DIN 5031, Bl. 1, Aug. 1970) on the 1 / e-th part dropped

§ is. The diagram shows that bex is very high

Flow rates of 100 m / h with the inventive pre

762144S 18.85.78

- 11 - "" "6I1 / 76

direction with only a single radiation source a kill rate of at least 10 is achieved for the type Bacterium E. CoIi, ie at least 99.9 % of the originally proposed

existing germs are destroyed.

With the new device according to the invention for decontamination of liquids, a device was created which, with the greatest possible structural simplicity, requires the least possible space and low »price has low maintenance with a high flow rate and high kill rate at the same time

for the medium to be sterilized. In particular, the

device according to the invention deflections and complex supply

restoration work on the wiring harness. The purification of the quartz

protection tube can be in conventional and extremely simple

Way to be carried out periodically.

7621448 18th osl 78

Claims (1)

- 12 - 64/76 ~ t pj ρ s ρ γ ü che 1 »Device for disinfecting liquids using ultraviolet radiation of mostly 25 * J nm wavelength, with a radiation source with a cylindrical delimitation from au disinfecting medium is flowed across, characterized in that that a pipe (3) is provided as a line for the medium (1) to be sterilized, which is at least a cylindrical quartz protective tube (6) is penetrated, which as a radiation source (10) is a low-pressure, high-current mercury vapor discharge tube with a discharge current density of at least 1 A / cm and a mercury vapor pressure of at most 0.5 Torr, in such a way that said medium (1) flows around the quartz protective tube (6). 2. Device according to claim 1, characterized in that the pipe (3) has a circular cross-section. 3. Apparatus according to claim 1, characterized in that the conduit pipe (3) has an oval or elliptical cross section having. H. Device according to claim 1, characterized in that 7621448 ia.Q5.7a A Λ (a a 3 - 13 - 64/76 a 3 * a »> · A as the pipe (3) has a rectangular cross-section. 5. The device according to claim 1, characterized in that the longitudinal axes (8j 9) of the quartz protective tube (6) and the Line pipe (3) with each other an angle C ^ between i »form 5 ° and 135 °. 6. The device according to claim 2, characterized in that the longitudinal axis (9) of the quartz protective tube (6) on the longitudinal I axis (8) of the pipe (3) is vertical. I 7 device according to one of the preceding claims 1-6, I characterized in that the external ·! diameter d of the quartz protective tube (6) at least 6 cm I, and the intensity of the 25 ¹ I nm line of the beam i radiation source (10) on the surface of the quartz protective ear ^ II x 6 cm 2 1 (6) greater than 30. - ^ - mW / em. I 8. The device according to claim 1, characterized in that i at most four each containing a radiation source (10), »'! the conduit pipe (3) penetrating quartz protective tubes (6) '; are provided. 9. Apparatus according to claim 1 or 8, characterized in that 7621448 05/18/78 - 14 - 64/76 £ ee—- - ■ ο t e-- \ = I ¹ ? CHl that the inner diameter D or the minimum clear width E of the conduit pipe (3) and the diameter d of the quartz protective tube (6) are dimensioned such that the absorption of the radiation of the 254 nm Hg line on the way from a point (A; B) on the surface of a quartz protective tube (6) to a point (A ¹ ; B ¹ ) on the inner wall of the conduit pipe (3) along a straight line, both on the surface of the quartz protective tube (6) and on that of the conduit pipe (3) is vertical, through the medium to be sterilized is 50 to 80 % . | 10. Apparatus according to claim 1 or 8, characterized in that the length L of the conduit pipe (3) measured on his Inner diameter D obeys the relationship D <T L <3D. 11. The device according to claim 1, characterized in that the radiation source sin low-pressure EQahstiOm mercury vapor discharge tube is provided in single-piston design. ■ - . 7621448 05/18/78