CS260680B1 - Hygrometer sensor, especially for heat flow measurement - Google Patents

Abstract

The solution relates to a hygrometer sensor for measuring heat flow, used in an aspiration compensation hygrometer. The sensor consists of a system of parallel and/or series-connected thermocouples arranged in a planar formation surrounded by thresholds enabling the creation of an active water surface and according to the invention, its active surface between the thresholds is assigned: a homogenizing grid made of a thermally conductive material, for example copper.

Description

The invention relates to a hygrometer sensor, in particular for measuring the heat flux.

In textile finishing machines, often heated air is used to dry large quantities of goods. In order to achieve efficient use of drying air, these machines are equipped with a number of hygrometers, based primarily on the comparative aspiration principle. Hygrometers contain sensors for measuring heat flux (called alpha meters). These surface sensors are generally installed in hygrometers so that one surface, the bottom surface, is attached to the surface of the body at a known temperature and their other surface is bounded by suitable thresholds, with a water layer between them. This layer of water is blown by a drying air stream which absorbs moisture when the moist goods are dried and evaporates the water covering the sensor while cooling. This creates a condition where the described sensor can indicate the heat flux dependent on the humidity of the blow drying air.

The disadvantage of these surface sensors is that in order to achieve the required working conditions, the blowing air must have a certain speed in contact with the water surface and the entire surface of the sensor must be covered with a water layer. Since the water still evaporates, new water must be supplied in a larger quantity than it evaporates in order to at the same time achieve the cleaning of the process-clogged sensor. However, this increase in the amount of water undesirably prolongs the reaction time of the hygrometer to determine the drying air humidity.

It is an object of the present invention to overcome these disadvantages of the sensors used for measuring heat flow.

260 680

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sensor for measuring the heat flow so as to ensure its self-cleaning with water from technological products, while achieving the shortest possible reaction time of the sensor.

The object of the invention is to provide a heat flux sensor according to the invention, characterized in that a homogenizing grid of thermally conductive material with a thermal conductivity higher than the thermal conductivity of water is arranged between the thresholds fixed on the upper active surface of the sensor. the upper surface of the sensor is smaller than the dimension of the smallest of the holes formed in the homogenization grid. The homogenization grid according to the invention has a high thermal conductivity which guarantees maximum utilization of the active surface of the sensor. Furthermore, this high-velocity homogenization grid homogenises the temperature of the water over the entire active surface of the sensor and its lesser wettability allows for a self-cleaning effect.

Further advantages and features of the invention will become apparent from the description of an exemplary embodiment of the sensor shown in cross-section of the accompanying drawing.

The hygrometer operating on the comparative aspiration principle consists of a lower body 14 on which the heat flux sensor 12 is mounted. This sensor 12 is plate-shaped and comprises built-in miniature thermocouples 13 arranged either in series and / or in parallel. This heat flux sensor 12 is connected via a power line to a measuring device 6, for example a recording millimeter. The thresholds 10 are fastened to the upper active surface of the heat flow sensor 12, between which water 9 is fed through a supply channel 15 formed in the lower body 14. Between the thresholds 10, a flat homogenization grid 6 is placed in the formed shoulder and fixed by means of adjustable holders 2. .

This homogenization grid 6 is made of a thermally well conductive material having a thermal conductivity coefficient higher than that of water. Preferably, the material is copper, brass, bronze and the like, suitably selected openings of the grid 6 and the connecting bridges between these openings ensure a constant leveling of the water level JB on the upper surface of the homogenizing grid 3 into a solid water surface. The gap between the homogenization grid 3 and the upper surface of the heat flow metering sensor 12 is smaller than the smallest dimension of the smallest hole formed in the homogenization grid

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The entire heat flow sensor 12 is covered by a lid

16. creating a space for measuring itself around said sensor 12. A hole is formed in the bottom of the lid 16 into which the nozzle 7 of the upper exchanger 6 of the measured air flow 4 is inserted. In the side wall of the lid 16 there is a discharge pipe 11 for exhausting both the measured air 4 and water 9 running over the thresholds 10 of the sensor 12 for measuring heat flux.

The operation of the heat flux sensor in a hygrometer is as follows. The water 9 passing through the inlet duct 15 extends onto the surface of the heat flow sensor 12 and accumulates in the space enclosed by the threshold 10 until the upper surface of the dome canopy touches the lower surface between the thresholds 10 of the inserted homogenization grid 3. 9, a similar tension is generated as between water 9 and the active surface of the sensor, but acting in the opposite direction. Both, the opposing voltage creates a transverse force causing the space between the heat flow sensor 12 and the homogenization grid 3 to fill completely. only penetrates the water 9 at a random place through the inserted homogenizing grid 3, the water level 8 is united in the whole area and finally the water 9 overflows over the thresholds 10. During the blowing of the water level 8 with the measured wet air stream 4. into the space where it hits the water level 8 The water 9 evaporates the more, the less moisture the measured air 4 contains. However, the inserted homogenization grid 3 evenly distributes the heat flux over the entire active surface of the sensor 12 for water. measuring the heat flux, thereby substantially reducing the reaction time of the apparatus and ensuring efficient use of the entire active surface of the heat flux sensor 12. The water 9, which passes over the thresholds 10 during the measurement, is discharged from the interior of the lid 16 together with the measured air 4 through the exhaust duct 11 and at the same time flushes away all impurities and technological fumes, e.g. always clean and there is no need to interrupt the measurement.

Claims (1)

SUBJECT OF THE INVENTION 260 680 A hygrometer sensor, in particular for measuring the heat flux, consisting of a system of parallel and / or series connected thermocouples arranged in a surface formation surrounded by thresholds for generating an active water level, characterized in that between the thresholds (10) mounted on the upper active surface of the sensor (12). ), a homogenizing grid (3) of thermally conductive material having a thermal conductivity higher than the thermal conductivity of water (9) is disposed, the dimension of the gap between the homogenizing grid (3) and the upper surface of the sensor (12) being smaller than the smallest of the holes in the homogenization grid (3).