Fluid treatment system and process

Abstract

PCT No. PCT / CA94 / 00125 Sec. 371 Date Oct. 17, 1994 Sec. 102(e) Date Oct. 17, 1994 PCT Filed Mar. 4, 1994 PCT Pub. No. WO94 / 20208 PCT Pub. Date Sep. 15, 1994A fluid treatment system includes one or more radiation sources arranged in an irradiation zone with a treatment zone through which fluid to be treated passes and is irradiated. The radiation zone has a closed cross section to maintain the fluid within a predetermined maximum distance form he radiation source. Preferably, the irradiation zone comprises a reduced cross-sectional area perpendicular to the direction of fluid flow and thus the fluid flow velocity is increased through the irradiation zone.

Description

TECHNICAL FIELDThe present invention relates to a method of treating fluid by providing a gravity fed flow of fluid to an irradiation zone comprising at least one radiation source and having a closed cross-section which confines the flow of fluid within a predefined maximum distance from the at least one radiation source.The present invention also relates to a novel method of cleaning a radiation source assembly located within a fluid flow wherein the exterior of the source is swept by a cleaning member containing an appropriate cleaning fluid.The present invention also relates to a novel system for treating fluid by exposing it to radiation. Specifically, the present invention relates to a novel gravity fed system for treating fluids comprising a treatment zone which includes a irradiation zone configured to provide a fixed fluid geometry relative to the radiation sources.The present invention also relates to a novel radiation source module for use in a fluid treatment system. Spec...

AI Technical Summary

Benefits of technology

Preferably, the irradiation zone is disposed within a fluid treatment zone including an inlet transition region and an outlet transition region. The inlet transition region receives the fluid flow from the fluid inlet and increases its velocity prior to entry thereof into the irradiation zone. The outlet transition region receives the fluid flow from the irradiation zone and decreases the velocity of the fluid flow prior to its entry into the fluid outlet. Thus, the fluid flow velocity is only elevated within the irradiation zone to reduce hydraulic head loss of the fluid flow through the system. It will be appreciated by those of skill in the art that one or both of the inlet transition region and the outlet transition region may comprise a tapered section (described in more detail hereinbelow). Alternatively, a "bell-mouth" shaped inlet and outlet may be utilized. In either case, the underlying result is a reduction in hydraulic head loss.

Problems solved by technology

.Iadd.rates.Iaddend., accurate fluid level control is difficult to achieve in gravity fed systems, fluctuations in fluid level are inevitable.

Such fluctuations could lead to non-uniform irradiation in the treated fluid.

However, disadvantages exist with the above-described systems.

Depending upon the quality of the fluid which is being treated, the sleeves surrounding the UV lamps periodically become fouled with foreign materials, inhibiting their ability to transmit UV radiation to the fluid.

Of course, this required surplus UV capacity adds to the expense of installing the treatment system.

Depending upon the number of frames to be cleaned at one time and the frequency at which they require cleaning, this can also significantly add to the expense of installing, maintaining and operating the treatment system.

If the frames are in a closed system, removal of the frames from the fluid for cleaning is usually impractical.

Cleaning such closed systems suffers from the disadvantages that the treatment system must be stopped while cleaning proceeds and that a large quantity of cleaning solution must be employed to fill the treatment enclosure.

An additional problem exists in that handling large quantities of acidic cleaning fluid is hazardous and disposing of large quantities of used cleaning fluid is difficult and / or expensive.

Of course open flow systems suffer from these two problems, albeit to a lesser degree.

Indeed, it is the belief of the present inventor that, once installed, one of the largest maintenance costs associated with prior art fluid treatment systems is often the cost of cleaning of the sleeves about the radiation sources.

Another disadvantage with the above-described prior art systems is the output of the UV lamps.

Unfortunately, the UV lamps in the prior art systems were required to be about five feet in length to provide the necessary wattage of UV radiation.

Accordingly, the UV lamps were relatively fragile and required support at each end of the lamp.

This increased the capital cost of the system.

Further, due to the somewhat limited output wattage of the UV lamps in the prior art systems, a great number of lamps were often required.

Such a high number of lamps adds to the above-mentioned costs in cleaning lamps as well as the cost of maintaining (replacing) the lamps.

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