Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Calorimeter
Reexamination Certificate
1998-08-11
2001-10-30
Warden, Jill (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Calorimeter
C422S084000, C422S085000, C436S132000, C436S147000, C073S023300
Reexamination Certificate
active
06309599
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an apparatus for determining or metering a given substance content of a fluid.
BACKGROUND OF THE INVENTION
Such apparatuses are already known for testing the alcohol content in the exhaled breath, and estimating the alcohol content of the blood.
Among these known apparatuses for testing the percentage of alcohol, an ethylometer or Alcotest™ currently available in the market is shown on
FIG. 1
of the enclosed drawings and comprises:
a means for sensing the alcoholic vapors in the breath, comprising a porous reactant mass
1
which progressively changes color by chemical reaction with said alcoholic vapors according to the volume of gas flowing through said mass,
a hollow tube
2
opened at its longitudinal ends, wherein said mass is housed so that the exhaled air entering the tube by one end passes through the mass and flows out by the other end,
a means for metering the alcohol content in the breath, comprising a graduation
3
on the portion of the tube containing the reactant mass, said graduation being calibrated according to a predetermined volume of gas passing through the mass, and
a means for limiting the gas volume passing through the tube, comprising a flexible inflatable bladder
4
, intended to be connected to one end of the tube and the inflation of which is limited to the aforementioned predetermined calibrating volume, said bladder being provided with a valve at its nozzle.
The operation of this Alcotest™ consists of blowing into the limiting bladder until it is completely full, then completely emptying the bladder through the tube after inserting the nozzle
5
of the bladder onto an end of the tube, and finally comparing the graduated mark of reference
3
with the length of reactant which changed color, to obtain an evaluation of the alcohol content of the blood. However, this type of ethylometer exhibits many drawbacks, in particular risks of leakage in the limiting bladder itself and at its connection to the tube, whereas the apparatuses have no tightness deficiency. There results a great overcost to obtain such as tightness.
This apparatus is also complicated in use since it requires three separate operations for the user. On the other hand, when the test is negative, the reactant mass does not change color but reacts with the water vapor contained in the exhalation, which makes the tube unusable, namely inoperable for a subsequent use. However, nothing on the tube let's know whether it is unused or has already been used during a negative test, since the tube and the inflatable bladder are in two separated parts.
The object of this invention is therefore to overcome the aforementioned drawbacks and to provide a novel light-weight portable apparatus for determining or metering a given substance content of a fluid, which is simple to manufacture and to use.
SUMMARY OF THE INVENTION
In this respect, this invention provides an apparatus for determining a given substance content of a fluid, comprising: a means for sensing the presence of said substance in the fluid, comprising a porous reactant mass which progressively reacts with said substance according to the fluid volume flowing through the mass, said porous mass being generally selected so that it turns color during the chemical reaction with the substance,
a hollow tube opened at its two longitudinal ends, wherein said mass is housed,
a means for determining the substance content of the fluid, comprising for instance a graduated metering means on the longitudinal portion of the tube containing the reactant mass, said means being calibrated according to a predetermined fluid volume flowing through the mass,
wherein it comprises a means for monitoring the fluid volume passing through the tube, comprising a heat sensitive indicator for indicating that the reactant mass has reached a critical heating temperature corresponding to a fluid volume flowing through the mass equal to the aforementioned predetermined calibrating volume did pass through the tube and hence that the user must stop blowing.
The invention is therefore based on the use of the exothermic reaction between the reactant mass and the fluid and onto the correlation between the fluid volume passing through the mass and the heating temperature thereof.
In a first preferred embodiment of the invention, the aforementioned heat indicator comprises a reactant solution such as an ink which instantaneously turns color and in a non reversible way when said critical temperature is reached. In an alternative embodiment, this reactant solution is absorbed into a chip which is secured to or embedded into the inner or outer walls of the tube, at the vicinity or at the level of said reactant mass.
According to another inventive feature, the indicator is arranged on the tube periphery at the level of the porous reactant mass and in a determined position for serving at the same time as a reference mark for determining the substance content of the fluid. The heat indicator may be carried by a removable ring for a reuse of the indicator onto another tube, when the heat indicator could be dissociated from the reference mark and positioned at the downstream end of the reactant mass.
In another embodiment, said heat indicator comprises an acoustic alarm or a light signal which is activated when the critical temperature is reached.
Still in another embodiment, said heat (thermal) indicator comprises a temperature sensor and a means for displaying the sensed temperature.
According to another inventive feature, the apparatus comprises an element for indicating the apparatus's used or unused state, said indicating element consisting of a non reversible heat indicator.
Indeed, even when the test is negative, the exothermic reaction is produced and therefore activates the heat sensitive indicator which indicates that the apparatus has already been used.
According to still another inventive feature, the apparatus comprises an element for indicating the apparatus's out of date or in date state, said indicating element consisting of a non reversible heat sensitive indicator, and the critical temperature of which is set at the temperature at which the reactant mass is likely to degrade by the action of an external heating, for instance by an extended exposure of the apparatus under the sun.
The critical temperature is advantageously selected in the range of 45° C. to 70° C., wherein the heating curve of the exothermic reaction with respect to the fluid volume hardly varies with the ambient temperature. Preferably, the critical temperature is substantially equal to 55° C.
The inventive apparatus may be used for instance as alcotest or for metering the pollution rate of nitrogen monoxide, nitric vapor or carbon dioxide in air, or still for metering a given substance rate in a liquid.
REFERENCES:
patent: 3459508 (1969-08-01), Miczka
patent: 3823382 (1974-07-01), Gaddy
patent: 4300385 (1981-11-01), Albarda
patent: 4354854 (1982-10-01), Fritze et al.
patent: 4791065 (1988-12-01), Rislove
patent: 5171535 (1992-12-01), Lamont
patent: 43042 (1982-01-01), None
patent: 480177 (1992-04-01), None
Cross LaToya I.
Metrologie et Systemes Industriels de Regulation (M.E.S.I.R. S.A
Morris Duane
Warden Jill
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