Liquid purification or separation – Processes – Including controlling process in response to a sensed condition
Reexamination Certificate
1999-02-01
2001-05-22
Simmons, David A. (Department: 1724)
Liquid purification or separation
Processes
Including controlling process in response to a sensed condition
C210S760000, C422S003000, C073S019010
Reexamination Certificate
active
06235207
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for measuring the degree of treatment of a medium by a gas. In one particular embodiment, the present invention relates to a method and apparatus for determining the degree of oxidative treatment of a medium, such as water, by measuring the total amount of oxidative agent, such as ozone, passing through the water without undergoing a conversion to oxygen.
BACKGROUND TO THE INVENTION
In many areas, a gas is used as a processing agent to treat a material. Examples of this include water treatment, waste water treatment and chemical oxidation (i.e. bleaching).
Accordingly, various different sensors have been developed to measure the level of a gas in a liquid. These include ORP sensors, photometric devices and electrolytic devices.
Ozone is used in various applications in industry and accordingly, sensors for detecting the concentration of ozone have been developed. Typically, these operate by passing ultraviolet light through a fluid stream and measuring the ultraviolet light which is received on a detector. Another type of gas sensor is disclosed in U.S. Pat. No. 5,167,927 to Karlson. Karlson discloses a monitor which measures the heat energy which is released when a gas, eg. ozone, is catalytically converted to a different compound (eg. oxygen).
One example of the use of ozone is to purify water for drinking by passing ozone through the water to kill microorganism contaminants such as bacteria present in the water. Various processes to treat water have been developed using combinations of filtration and ozonation.
For example, U.S. Pat. No. 5,683,576 to Olsen describes an apparatus for treating contaminated water by passing ozone through the water. In the system disclosed by Olsen, an ozone containing gas is passed through the water to be treated, until the instantaneous concentration of ozone in the head space above the water being treated reaches a predetermined level. Then, the flow of ozone through the water continues for a predetermined period of time.
The amount of ozone which must be passed through the water to purify it to any particular state will vary depending upon the initial quality of water to be treated. For example, untreated well or lake water may require a higher degree of purification than treated city water which has previously been treated to some degree.
One disadvantage of Olsen is that it can not be reliable used with such disparate types of water supply. Olsen does not monitor the total amount of ozone which passes through the water unreacted. Thus, the actual degree of treatment of the water is not measured. The system is designed only to ensure that a predetermined minimum amount of ozone passes through the system unreacted. The system makes the assumption that once the concentration of ozone reaches the predetermined level, that it does not subsequently drop below that level, or rise above that level. Further, it assumes that once the water to be treated has been exposed to the preset ozone concentration for a predetermined time that the water is suitable for use. However, depending on the degree of contamination of the water to be treated, the time required to treat the material will vary.
In Olsen, the amount of unreacted ozone passing through the system prior to the time when the instantaneous concentration reaches the predetermined level is not measured. Further, the amount of unreacted ozone passing through the system measured during the predetermined amount of time after the predetermined instantaneous concentration is reached is not measured. Thus, the actual degree of treatment of the water is not measured.
Another disadvantage of the method of Olsen is that, in some applications, it is desirable to monitor the degree of treatment of material as it is being oxidized.
Accordingly, there is a need for a method and apparatus to accurately measure the amount of treatment to which water has been subjected by passing ozone through the water. Further, there is a need to do so on a cost effective scale.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a method of treating a material to a predetermined state with a reactable gas comprising the steps of:
(a) contacting the reactable gas and the material to treat the material and obtaining treated material, the by-product and unreacted gas;
(b) comparing the unreacted gas having treated the material without having being converted into the by-product with a preset amount corresponding to a predetermined state of treatment of the material; and,
(c) treating the material until a prespecified condition is met, the prespecified condition selected from the group:
(i) until the total amount of unreacted gas is at least equal to the preset amount, or
(ii) for a predetermined time.
In one embodiment, the method additionally comprises the steps of:
(a) stopping the flow of the reactable gas after the total amount of unreacted gas is at least equal to the preset amount; and,
(b) issuing a signal to a user that the material has been treated to the predetermined state.
In another embodiment, the material to be treated comprises water and the reactable gas is ozone and the method further comprises passing the reactable gas as finely dispersed bubbles through the water.
In another embodiment, step (b) comprises treating at least a portion of the unreacted gas to produce a signal and determining the amount of unreacted gas based on the signal produced.
In another embodiment, step (b) comprises subjecting at least a portion of the unreacted gas to a chemical reaction to produce heat and determining the amount of unreacted gas based on the heat produced. In a preferred embodiment, all of the unreacted gas is subjected to the chemical reaction.
In another embodiment, the step of determining the amount of unreacted gas based on the heat produced comprises measuring the amount of heat produced; and, calculating the total amount of heat produced by the unreacted gas, wherein the preset amount is determined based on the total amount of heat released by the unreacted gas when the material has been treated to the predetermined state of treatment.
In another embodiment, the step of measuring the amount of heat produced comprises measuring the change in temperature of the unreacted gas from subjecting the unreacted gas to the chemical reaction; and, correlating the temperature differential to the amount of unreacted gas.
In another embodiment, the step of measuring the amount of heat produced comprises:
(a) measuring a first temperature of the unreacted gas;
(b) measuring a second temperature of the gas after subjecting the unreacted gas to the chemical reaction;
(c) calculating the difference between the first temperature and the second temperature; and,
(d) correlating the temperature differential to the amount of unreacted gas.
In another embodiment, the material to be treated comprises water and the reactable gas is ozone and the step of subjecting at least a portion of the unreacted gas to a chemical reaction comprises exposing the ozone to a catalyst to convert ozone into oxygen.
In another embodiment, the method further comprises the step of forming a liquid solution containing microbubbles of the reactable gas prior to contacting the reactable gas with the material.
In another embodiment, the method further comprises passing a liquid and the reactable gas through a prandtl layer turbine and a reduced pressure zone downstream of the prandtl layer turbine prior to contacting the reactable gas with the material.
In another embodiment, the method further comprises passing the material to be treated and the reactable gas through a prandtl layer turbine and a reduced pressure zone downstream of the prandtl layer turbine.
In accordance with another aspect of the present invention, there is provided an apparatus for measuring the degree to which a material has been treated with a reactable fluid, the reactable fluid capable of treating the material and in the process being converted into a by-product,
Bereskin & Parr
Fantom Technologies Inc.
Lawrence Frank M.
Mendes da Costa Philip C.
Simmons David A.
LandOfFree
Method for measuring the degree of treatment of a medium by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for measuring the degree of treatment of a medium by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for measuring the degree of treatment of a medium by... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2444995