EP0511582A1

EP0511582A1 - Device for detecting atmospheric impurities

Info

Publication number: EP0511582A1
Application number: EP92106868A
Authority: EP
Inventors: Bruno Massalongo; Paolo Bolla
Original assignee: EUROGIADA Srl
Current assignee: EUROGIADA Srl
Priority date: 1991-04-29
Filing date: 1992-04-21
Publication date: 1992-11-04
Also published as: IT1249197B; ITVR910037A1; ITVR910037A0; CA2067287A1

Abstract

The device for detecting atmospheric impurities has a detector (1) with a threshold adjuster (11), for detecting the presence of gaseous impurities in the ambient atmosphere, which emit variable control signals. The detector (1) is connected to analogue instruments (2) for displaying the level of the impurities represented by the variable control signals, and the threshold adjuster (11) is connected to an alarm actuator (6) for selectively or simultaneously controlling an acoustic alarm (7), a visual alarm (8), a solenoid valve for closing gas ducts and/or a relay (10) for disactivating power lines.

Description

The present invention relates to a device for detecting atmospheric impurities in enclosed spaces, such as living spaces, public places, vehicle interior compartments and the like.
Gas detectors, in particular detectors which are sensitive to methane gas or carbon dioxide or to carbon monoxide, for household use, are currently known; said detectors are suitable for indicating, by means of simple alarms, usually acoustic ones, the presence of explosive or noxious gases in an amount which exceeds a preset threshold. This threshold is usually set at a density level per cubic meter of explosive or noxious gas in air which is lower than the characteristic risk threshold of the particular gas.
Such devices, however, are unable to indicate the quality of the air in the enclosed space in which they are located. In fact they only have alarms or controls which are activated when the preset threshold is reached but provide no information at lower levels, which would be a precise and definitely better item of information regarding the state of the air.
The aim of the present invention is to eliminate or substantially reduce the problems described above by providing a device for detecting atmospheric impurities which provides a precise assessment of the atmosphere of the enclosed space in which it is located or, so to speak, of its "degree" of pollution.
Within the scope of the above aim, an object of the present invention is to provide a detection device which also indicates that specific danger thresholds have been exceeded for at least one noxious gas.
Not least object of the present invention is to provide a detection device which is highly reliable, easy to install and can be produced at competitive costs.
This aim, the objects mentioned and others which will become apparent hereinafter are achieved by a device for detecting atmospheric impurities, according to the invention, which comprises means for detecting the presence of gaseous impurities in the atmosphere, said means being suitable for emitting variable control signals, means for displaying the level of said impurities by displaying levels of said variable control signals, and an electric power supply for said detection means and for said display means.
Further characteristics and advantages of the invention will become apparent from the description of a preferred but not exclusive embodiment of a device for detecting atmospheric impurities according to the invention, illustrated only by way of non-limitative example in the only figure in the accompanying drawing, which is a block diagram of a device according to the invention.
With reference to the described figure, a device for detecting atmospheric impurities comprises means for detecting the presence of gaseous impurities in the atmosphere, designated by the general reference numeral 1.
The detection means 1 generate variable control signals for controlling means, designated by the general reference numeral 2, for displaying the level of impurities by displaying levels reached by the variable control signals which flow in the electrical connection shown in solid lines in the figure.
The detection means 1 and the display means 2 are furthermore powered by an electric power supply 3.
The detection means 1 comprise at least one sensor, or a plurality of sensors, depending on whether the device must be sensitive to one or more types of impurities in the air. The type of sensor or capsule suitable for being used comprises a resistor, for example of the layer type or of the filament-in-air type and in any case comprising catalyst materials, such as for example platinum and stannous dioxide, which is initially raised and kept at a temperature of approximately several tens of degrees Celsius and varies its resistance as a function of the amount of impurities of one or more gases present in the atmosphere. The resistance variations of the resistor entail variations of the absorbed current, i.e. of the dissipated power, which become the variable control signals directed to the display means 2.
Capsules of the described type are commercially available in a wide range of formats, sizes, power dissipation capabilities and detectable gases, such as for example the sensors 812 and 813 manufactured by the Japanese company Figaro and the sensor FGS-7712 of the Japanese company Hakuto.
The display means 2 comprise analogue instruments, for example of the dial or deflection type, or digital instruments. Preferred display means may be cathode-ray-tube displays, liquid-crystal displays or LED displays, which have the advantage of being readable under any lighting condition.
As regards the liquid-crystal displays and LED displays, they can either provide a direct reading of the momentary value of the impurities, which are indicated by means of a string of numbers, or a history reading, and thus a time-based control. In the latter case, they are matrices of liquid crystals or of LEDs which have a time-related weight factor on the abscissa and a weight factor which indicates the impurities on the ordinate. The activation of elements within this matrix, according to a well-defined proportionality with respect to the ordinates and depending on the provided time interval, provides in the course of time a chart of the impurities condition in the enclosed space in which the device according to the invention is inserted.
For LED displays it is possible to think of the so-called "traffic lights", usually composed of at least one red LED, at least one yellow LED and at least one green LED, which provide a qualitative evaluation of the atmosphere quality state, constantly updating the display according to the changes in the degree of pollution of the ambient atmosphere.
In order to make the detection means 1 independent from the ambient variations in temperature and/or humidity, it is preferable to prearrange a system 4 for controlling the temperature and, possibly, the humidity which subjects the detection means 1 to thermostatic control. Said control system 4 thus allows to keep the sensitivity of the detection means 1 constant, even if the climatic and ambient conditions change.
The variable control signals can advantageously control a ventilation system 5 so as to continuously vary the rotation rate of the motor or motors of said ventilation system 5 in order to provide an exchange of air between the enclosed space and the outside which is more or less intense according to the degree of pollution detected.
The variable control signals can conveniently also control alarm means which warn that a preset threshold of risk for the health of the persons present in the controlled enclosed space is exceeded. The alarm means comprise an alarm activator 6 the threshold whereof is variable according to the different type of gas being monitored, which can selectively or simultaneously control an acoustic alarm apparatus 7, a visual alarm apparatus 8, a solenoid or electric valve 9 for closing gas ducts and a relay 10 for example for deactivating the power lines.
The above mentioned risk thresholds can be adjusted through adjustment means, designated by the reference numeral 11 in the figure, which can comprise at least one rotary potentiometer or at least one decade potentiometer or an adjustment device provided with a display of the selected level by numeric indication; such adjustment device can be of the pushbutton type or of the gear type. The adjustment means 11 activate the alarm activator 6 if at least one risk threshold is exceeded.
Conveniently, the electric power supply 3, which must provide the various components of the above described circuit with a voltage of for example 5 volts, can comprise a power supply/transformer which converts the alternating mains voltage into the required 5 volts, or a power supply which converts a direct voltage, for example of 12 volts, into the supply voltage of the circuit, and a battery pack capable of providing, in any case, the state of the enclosed space even in case of power failure at the mains or other source. Said battery pack can conveniently be of the rechargeable type, and can thus be recharged when the power supply voltage of the device according to the invention is available. In this manner, the device, in its various versions, can be advantageously located in household rooms, work rooms and the like, as well as in interior compartments of motor vehicles, boats and aircraft.
In practical tests it has been observed that the invention achieves the intended aim and objects, constituting a considerable advance with respect to known alarm devices, since it provides its users with a reference (digits, color codes and the like) for deciding whether to ventilate a room even before risk thresholds are reached, and thus reduce pollution-related dangers in enclosed spaces.
The invention thus conceived is susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept. All the details may furthermore be replaced with other technically equivalent elements.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

Device for detecting atmospheric impurities, characterized in that it comprises detection means (1) for detecting the presence of gaseous impurities in the atmosphere, said detection means (1) being suitable for emitting variable control signals, display means (2) for displaying the level of said impurities by displaying levels of said variable control signals, and an electrical power supply (3) for said detection means (1) and for said display means (2).
Device according to claim 1, characterized in that said detection means (1) comprise at least one sensor or capsule for detecting the presence of impurities in the air.
Device according to claim 1, characterized in that the or each sensor comprises a resistor having a resistance which varies according to the degree of pollution of one or more specific polluting gases.
Device according to any one of the preceding claims, characterized in that it comprises a temperature control system (4) for providing thermostatic control of said detection means (1).
Device according to any one of claims 1 to 4, characterized in that said display means (2) selectively comprise analogue instruments and digital instruments.
Device according to claim 5, characterized in that said display means (2) comprise a cathode ray tube display.
Device according to claim 5, characterized in that said display means (2) comprise a liquid-crystal display.
Device according to claim 5, characterized in that said display means (2) comprise an LED display.
Device according to any one of the preceding claims, characterized in that it comprises at least one ventilation system (5) which can be controlled by said variable control signals and can be powered by said electrical power supply (3).
Device according to any one of the preceding claims, characterized in that it comprises alarm means (6,7,8,9,10) for indicating that one or more risk thresholds have been exceeded, said alarm means (6,7,8,9,10) being activatable by said variable control signals.
Device according to claim 10, characterized in that said alarm means (6,7,8,9,10) comprise a variable-threshold alarm activator (6) and an alarm apparatus (7,8) which can be activated by said alarm activator (6).
Device according to claim 10, characterized in that said alarm means comprise an acoustic (7) and/or visual (8) alarm apparatus.
Device according to claim 11 or 12, characterized in that said alarm means (6,7,8,9,10) comprise a variable-threshold alarm activator (6) which is suitable for activating a solenoid or electric valve (9) for closing gas ducts.
Device according to any one of claims 10 to 13, characterized in that said alarm means (6,7,8,9,10) comprise a relay (10).
Device according to any one of the preceding claims, characterized in that it comprises adjustment means (11) for presetting said activation and/or risk thresholds and activating said variable-threshold alarm activator (6).