Vaisala Oy

Vaisala Oyj

Lars Stormbom

Matti Lyyra

Jorma Ponkala

Jukka Leppänen

Ari Paukkunen

Veijo Antikainen

Pekka Belt

Hannu Jauhiainen

Ari Lehto

Petteri Survo

Jouko S Jalava

Eero Hiltunen

Jukka Lepp&auml;nen

Heikki Mesia

Jukka LEPPÄNEN

According to an example aspect of the present invention, there is provided a method in connection with a radiosonde, the method comprising measuring a humidity of the atmosphere at several different altitudes in the atmosphere, measuring a pressure at several different altitudes in the atmosphere or calculating the pressure from an altitude of the radiosonde obtained from GPS or other satellite navigation system, measuring or estimating a temperature of a humidity sensor, and measuring a relative humidity by a capacitor with a polymer insulator, wherein the relative humidity value is corrected based on a correction factor, which is a function of pressure, humidity sensor temperature, and relative humidity, such that the humidity value decreases when pressure decreases.

Method in connection with a radiosonde and system

The invention relates to a method and apparatus for measurement of total water content in a liquid. According to the method, the relative water content (aw) of the liquid is measured in a first measurement step at a first temperature (T). According to the invention, the temperature of the liquid under measurement is altered from the first temperature (T) and the relative water content is measured in a second measurement step at the second, altered temperature (T), whereby, based on these at least two measurement values (aw()T, aw()T), the total water content is determined from the temperature dependence of water dissolution into the liquid under measurement.

Method and apparatus for defining water content of a liquid

A method and apparatus for measuring the water content of a liquid, including a method step for electrically measuring the property of the liquid for one parameter. The properties of the liquid are measured at least substantially simultaneously by another electrical method, where the properties of the liquid are measured using both a relative-value and an absolute-value measurement method.

Method and apparatus for measuring water content

A method and system relating to an improvement in measuring accuracy of a gas concentration sensor, the method comprising the steps of measuring a parameter of the sensor, the parameter being a resistance or a capacitance, that is sensitive to the gas or its concentration being measured, and simultaneously changing the temperature of the sensor in a cyclic manner. The parameter of the sensor being measured is measured more than two times or continuously during each heating cycle. The measured parameter value is filtered to obtain a signal component associated with the fundamental frequency of the heating cycle for use at a later step, and the thus filtered signal component is used in the correction and/or calibration of actual output signal of the sensor.

Measurement method and system for a humidity or gas concentration sensor

The invention relates to a method for improving the selectivity of a polymer film gas sensor. According to the method, the gas sensor is heated and a sensor parameter sensitive to the variable under measurement is recorded. According to the invention, the parameter of the sensor sensitive to the variable under measurement is measured at a plurality of instants during both the heating period and the cooling period of the sensor, a hysteresis function of the sensor response is formed over the heating and cooling periods, and on the basis of the hysteresis function, the concentration of each measured gas component is determined.

Method of improving the selectivity of a polymer-film gas sensor and a

The invention relates to an indirect measurement method of dewpoint or gas concentration and an apparatus suited for prediction of icing. The method is based on measuring the relative concentration of the gas directly and simultaneously measuring the temperature of the element (3) measuring the relative concentration of the gas. According to the invention, the temperature of the relative value measuring element (3) is shifted so as to bring the operation of the measuring element to a measurement range of maximally high sensitivity.

Method of measuring dewpoint or gas concentration and apparatus for

The invention relates to a method and sensor structure for measuring the concentration of nonpolar gases such as carbon dioxide. According to the method, the concentration of the nonpolar gas adsorbed/absorbed in a polymer film (2) is determined by detecting the weight of the polymer film (2). According to the invention, the dielectric coefficient of the polymer film (2) is measured, and on the basis of this, a correction is made in the concentration measurement result obtained from the weight measurement. (FIG. 1)

Method of measuring concentration of nonpolar gases such as carbon

Detector and method for detecting the presence of a liquid, such as water dew or of ice, or for detecting a change of phase in liquid, based on a change in an electrical resistance. The detector comprises a substrate onto whose face one or several resistor patterns are applied. For detecting the presence of a liquid or ice or equivalent by a change in the detector resistance, a low-mass detector resistor pattern is applied onto a substrate out of such a metal or equivalent as has a considerable dependence on temperature. On the substrate, there are contact patterns that feed a short pulse of electric current to heat the detector resistor as a short pulse, the presence of a liquid or ice and or a change of phase being detected by the change in resistance taking place during the short pulse. The thickness of the metal film in the resistor pattern (15) of the detector resistor (R.sub.det) is, as a rule, chosen as s&lt;1 .mu.m.

Detector and method for observation of the presence of a liquid and/or

The invention relates to a method of producing a microporous, gas permeable electrode structure, and to a corresponding electrode structure. According to the method, on a substrate (2) by means of a vacuum evaporation process is formed a first microporous electrode layer (4) using an angle (.alpha.) between the substrate (2) and the evaporation source (1) smaller than 90.degree.. According to the invention, on the first microporous layer (4) is formed another microporous layer (5) of a precious metal using essentially the same evaporation angle (.alpha.) as in the fabrication step of the first microporous layer (4).

Method of producing a microporous, gas permeable electrode structure and

Method, in particular in radiosondes, for measurement of relative humidity by using a capacitive humidity detector (10) or a combination of detectors (10.sub.1,10.sub.2 ;10P), as well as humidity detectors. In the detector, between the capacitor plates, an insulating material (12) is used, whose permittivity is a function of the amount of water vapor absorbed by the insulating material (12). The detector (10) or the combination of detectors is heated in order to remove any ice, frost or condensed humidity deposited on the face and/or in the environment of the detector. The detector capacitance (C.sub.M) or a part (C.sub.1 . . . C.sub.N) of same is heated, in time and/or in place, periodically by means of electric current (I). The detecting of the detector capacitance (C.sub.M) is carried out without measurement of the detector temperature after the detector capacitance or a part (C.sub.1 . . . C.sub.N) of same has cooled down substantially to the temperature of the environment where the ratio of the duration of the measurement cycle to the duration of the heating cycle is selected from a minimum range of 10 to one, up to a maximum range of 3000 to one.

Method for measurement of relative humidity, in particular in

Method, in particular in radiosondes, for measurement of relative humidity by using a capacitive humidity detector (10) or a combination of detectors (10.sub.1, 10.sub.2 ; 10P), as well as humidity detectors. In the detector, between the capacitor plates, an insulating material (12) is used, whose permittivity is a function of the amount of water absorbed by the insulating material (12). The detector (10) or the combination of detectors is heated in order to remove any ice, frost or condensed humidity deposited on the face and/or in the environment of the detector. The detector capacitance (C.sub.M) or a part (C.sub.1 . . . C.sub.N) of same is heated, in time and/or in place, periodically by means of electric current (I). The detecting of the detector capacitance (C.sub.M) is carried out without measurement of the detector temperature after the detector capacitance or a part (C.sub.1 . . . C.sub.N) of same has cooled down substantially to the temperature of the environment.

Method of measurement of relative humidity, in particular in

The invention concerns a capacitive humidity sensor (6) capable of being connected to a measurement device of dielectric factor and a method for producing the sensor. The sensor comprises a dielectric layer (3), whose dielectric factor changes according to the moisture content absorbed in the layer, and at least two galvanically isolated conductive layers (2,1) enclosing the dielectric layer (3), where one of the conductive layers (2) of the capacitor construction is provided with a random pattern of clefts (7), which allow an immediate communication of ambient air with the dielectric layer (3). According to the invention, the dielectric layer (3) has a solid structure without cracks corresponding to the clefts (7) of the conductive layer (2). The construction according to the invention offers a reduction of the capillary effect and associated hysteresis up to a complete elimination of the effect in some embodiments of the invention.

Capacitive humidity sensor construction and method for manufacturing the

This invention concerns a calibration method and compatible sensor construction for the determination of relative concentration of a gas or vapor. According to the method a sensor is brought to controlled conditions, in which at least one calibration point is determined, and then with the help of the calibration point measurement values the response of the sensor for the measured gas or vapor is computed. According to the invention, both the temperature of the sensor and the relative concentration of the desired gas or vapor is measured at the actual measurement site, and the temperature of the sensor is deviated from the ambient temperature so transiently that the partial pressure of the measured gas or vapor can be assumed to stay at least approximately constant at the measurement site, whereby the results of measurements performed at each deviated temperature level can be used for computing a correction factor for the calibration of the sensor. An improved measurement accuracy results from the uncomplicated calibration routine.

Calibration method for gas or vapor relative concentration sensor

This invention concerns a method for trimming a planar capacitor. According to the method, a laser emission is focused to an electrode of a capacitor formed on a substrate transparent to laser emission and including of an upper electrode, an insulation layer, and a lower electrode, in order to achieve a passivation effect on the electrode. The laser emission is focused according to the invention locally onto the lower electrode through the substrate in order to achieve a heating effect on the lower electrode, thereby oxidizing the electrode material so that the lower electrode is locally converted into an electrically nonconductive state while being protected by the substrate and the insulation layer. The trimming method in accordance with the invention is accurate and offers a stable capacitance value.

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Vantaa, Finland

Lars Stormbom