Multichamber UV purifying process

Claim 2

A process of purifying a fluid medium with ultraviolet radiation wherein the medium is passed through an apparatus including a photoreactor wherein it is exposed to the ultraviolet radiation and thereby irradiated, said process being characterized by: recirculating the irradiated medium through the apparatus and back through said photoreactor; drawing off a portion only of the recirculated medium from the apparatus to serve as the purified medium; concurrently with said withdrawal adding unpurified medium, in an amount equivalent to that so withdrawn, to the apparatus to be mixed with the irradiated medium remaining therein to produce a mixture of irradiated and nonirradiated medium; and irradiating said mixture while it is being recirculated through the apparatus.

Claim 3

A process as set forth in claim 1, wherein the recirculation is performed intermittently with a dwell period between each two periods of recirculation, said medium being drawn off only during said dwell periods.

Claim 4

A process of purifying a fluid medium with a predetermined minimum radiation dose of ultraviolet radiation wherein, at a given location, a number n, less than four, of flow paths for said medium are provided in juxtaposition to each other and the incident ultraviolet radiation is first introduced into one of said paths and permitted to escape from said one path into other of said paths, said process being characterized by: the relationship between the irradiation intensity, the character of the medium and the depth of the medium traversed by the irradiation being established so that not more than fifty percent of the incident radiation is absorbed by the medium in said one path and substantially the remainder escapes to a flow path immediately adjacent said one path; and the total radiation absorbed by the medium in all the flow paths does not exceed (1-0.5 n )·100 percent of the total incident radiation.

Claim 5

A process of purifying a fluid medium with a predetermined minimum radiation dose of ultraviolet radiation wherein, at a given location, a number n, less than four, of flow paths for said medium are provided in juxtaposition to each other and the incident ultraviolet radiation is first introduced into one of said paths and permitted to escape from said one path into other of said paths, said process being characterized by: the relationship between the irradiation intensity, the character of the medium and the depth of the medium traversed by the irradiation being established so that not more than fifty percent of the incident radiation is absorbed by the medium in said one path and substantially the remainder escapes to a flow path immediately adjacent said one path; and the total radiation absorbed by the medium in all the flow paths does not exceed (1-0.5 n )·100 percent of the total incident radiation.

Claim 6

A process as set forth in claim 3, wherein the same medium is passed through one of said paths and then through the other.

Claim 7

A process as set forth in claim 3, wherein the medium to be irradiated is first divided into two parts, the medium constituting one part is passed through one of said paths and the medium constituting the other part is passed through the other of said paths.

Claim 8

A process as set forth in claim 3, wherein the medium flowing through one of said paths is different than the medium flowing through the other of said paths.

Claim 9

A process as set forth in claim 3, wherein the radiation is within the wavelength range of 260 to 280 nm.

Claim 10

A process as set forth in claim 3, including the step of adding an oxidizing agent to the medium in time to be present in the medium during at least part of the time that the medium is receiving said radiation.

Claim 11

A process as set forth in claim 3, wherein the medium passing through at least one of said paths is recirculated and again subjected to the radiation while being recirculated, and some of the recirculated medium is drawn off to serve as the purified medium.

Claim 12

A process as set forth in claim 3, including the step of detecting the amount of radiation which is not absorbed in said flow paths and adjusting the rate of flow of the medium in relation to the detected amount of radiation by diminishing the rate of flow as the detected amount of radiation diminishes and by increasing the rate of flow as the detected amount of radiation increases, all while continuing to maintain the flow, to the end that the throughput is maintained as great as is reasonably possible while maintaining a predetermined minimum radiation dose.

Claim 13

A process as set forth in claim 9, wherein the recirculation is performed intermittently with a dwell period between each two periods of recirculation, said medium being drawn off only during said dwell periods.

Claim 14

A process as in claim 3 wherein the relationship between the irradiation intensity, the character of the medium and the depth is established so that an equal portion of the incident radiation is absorbed by the medium in each flow path.

Claim 15

A process of purifying a fluid medium with a predetermined minimum radiation dose of ultraviolet radiation wherein, at a given location, a number n, less than four, of series connected flow paths to be passed consecutively by said medium are provided in juxtaposition to each other and the incident ultraviolet radiation is first introduced into one of said paths and permitted to escape from said one path into other of said paths, said process being characterized by: the relationship between the irradiation intensity, the character of the medium and the depth of the medium traversed by the irradiation being established so that not more than fifty percent of the incident radiation is absorbed by the medium in said one path and substantially the remainder escapes to a flow path immediately adjacent said one path; the total radiation absorbed by the medium in all the flow paths does not exceed (1-0.5 n )·100 percent of the total incident radiation; and the relationship between the irradiation intensities effective in each one of said flow paths and the total rate of flow of the medium through all said flow paths being established so that the sum of the fractional doses applied to the medium being passed through each one of the series connected flow paths equals the predetermined minimum radiation dose applied to the medium when it has passed consecutively through all said flow paths.

Claim 16

A process of purifying a fluid medium with a predetermined minimum radiation dose of ultraviolet radiation wherein, at a given location, a number n, less than four, of series connected flow paths to be passed consecutively by said medium are provided in juxtaposition to each other and the incident ultraviolet radiation is first introduced into one of said paths and permitted to escape from said one path into other of said paths, said process being characterized by: the relationship between the irradiation intensity, the character of the medium and the depth of the medium traversed by the irradiation being established so that not more than fifty percent of the incident radiation is absorbed by the medium in said one path and substantially the remainder escapes to a flow path immediately adjacent said one path; the total radiation absorbed by the medium in all the flow paths does not exceed (1-0.5 n )·100 percent of the total incident radiation; and the relationship between the irradiation intensities effective in each one of said flow paths and the total rate of flow of the medium through all said flow paths being established so that the sum of the fractional doses applied to the medium being passed through each one of the series connected flow paths equals the predetermined minimum radiation dose applied to the medium when it has passed consecutively through all said flow paths.