Continous analyzer of volatile organic compounds, device and method for continuously assessing the quality of inside ambient air and use of said device for monitoring a ventilation installation

• US 20030012696A1
• Filed: 08/28/2002
• Published: 01/16/2003
• Est. Priority Date: 03/09/2000
• Status: Abandoned Application

• Current Assignee: Electricitã© De France
• Original Assignee: Electricitã© De France
• Inventors: Millancourt, Bernard
• Application Number:
  US10/220,104
• Publication Number:
  US 20030012696A1
• Time in Patent Office: Days
• US Class Current: 422/83
• CPC Class Codes: G01N 33/0004 Gaseous mixtures, e.g. polluted air
• CPC Class Codes: G01N 33/0014 by eliminating a gas by a chemical reaction G01N33/0013; a chemical reaction taking place or a gas being eliminated in one or more analysing channels G01N33/0024
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array
• CPC Class Codes: G01N 33/0032 using two or more different physical functioning modes
• CPC Class Codes: G01N 33/0047 Organic compounds
• CPC Class Codes: G01N 33/0049 Halogenated organic compounds
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/204998 Inorganic carbon compounds

Abstract

The present invention concerns a continuous analyser of volatile organic compounds (10) comprising a circuit (18) for the sequential processing of air such that the air is drawn in by a pump (17) through a filter (11) and scanned by a first sensor (15) for CO/VOC and the second sensor (16) for H₂O, either directly along a first pathway, or after passing through a cartridge (12) for retaining organic species along a second pathway; the switch over from one to the other of these two pathways being assured by an electric valve (13) controlled by a sequencer (14).

The present invention also concerns a device and a method for continuously evaluating the quality of interior ambient air.

Claims

1. Continuous analyser of volatile organic compounds characterised in that it comprises:

a measuring module comprising a first CO/VOC sensor (15) and a second H₂O sensor (16),

a sequential processing circuit for air comprising;

a filter (11)

a cartridge (12) for the selective retention of volatile organic compounds arranged on a first pathway (12) in parallel with a second direct pathway (11)

an electric valve (13) controlled by a sequencer (14), which assures the first pathway—

second pathway commutation

a pump (17) located downstream of the sensors (15, 16) in such a way that the air to be analysed is drawn in through a filter (11) and is transferred towards the CO/VOC (15) and H₂O (16) sensors either directly, or after passing through the cartridge (12)

a circuit (18) for processing the signals coming from the sensors (15, 16) and the sequencer (14), enabling the following three parameters to be obtained;

the water concentration of the air

the CO concentration of the air, on a sample with the VOCs removed

the VOC concentration, by calculating the difference in signals obtained using the CO/VOC sensor (15) when the air to be analysed is transferred towards this sensor either along the first pathway or along the second pathway.

2. Device for continuously analysing the quality of interior ambient air comprising a continuous analyser of volatile compounds according to claim 1, in which the measuring module also comprises sensitive elements of sensors for NO₂ (20) and CO₂ (21), and in which the sequential processing circuit for the air drawn in by the pump through the filter (11) initially scans the third sensor (20) and the fourth sensor (21) before being transferred towards the first sensor (15) and the second sensor (16) along the first or second pathway.

3. Device according to claim 2, in which the first, the second and the third sensors (15, 16, 20) are metal oxide chemical micro-sensors.

4. Device according to claim 2, in which the pump (17) is a membrane pump.

5. Method for continuously analysing the quality of interior ambient air, implementing the device according to any of claims 2 to 4, and which comprises the following stages:

the calibration curve for each of the sensors (15, 16, 20, 21) for measuring different compounds;

CO/VOC, H₂O, NO₂ and CO₂ is determined.

the influence of the majority interfering compounds is corrected by calculation.

the output signal from each sensor is transposed into measured compound concentration, while taking account of its calibration curve.

a quality index for each compound measured is determined by referring to an evaluation grid that gives an index value for each compound as a function of different thresholds limits for the concentrations of compounds, referring to health data.

an overall index of the quality of the air is obtained as a function of the different compound indexes obtained thereof.

6. Use of the device according to any of claims 2 to 4 for controlling a ventilation unit.