FR2850169A1 - Combined thermometer and hygrometer has pointers made from two materials in layers that respond to changes in temperature and humidity - Google Patents

Abstract

The combined thermometer and hygrometer consists of a transparent housing (4) marked with temperature and humidity scales and containing two pointers (1, 2), each made from layers of two different materials. The temperature pointer is made from a layer of aluminium stuck or affixed to a layer of plastic; the humidity pointed is made from a similar aluminium layer attached to a layer of paper. The combined thermometer and hygrometer consists of a transparent housing (4) marked with temperature and humidity scales and containing two pointers (1, 2), each made from layers of two different materials. The temperature pointer is made from a layer of aluminium between two micrometres and 1 mm thick, stuck or affixed to a layer of plastic between 10 micrometres and 1 mm thick; the humidity pointed is made from a similar aluminium layer attached to a layer of paper between 20 micrometres and 1 mm thick. The two pointers have tips (6) of thick coloured paper and are attached by a rubber strip (8) to a block (3) mounted on the base of the housing, which has an air inlet and outlet (5).

Description

The present invention relates to a thermometer-hygrometer

  with bending needles depending on the temperature and humidity of the ambient air.

  Thermometers-hygrometers (even the simplest) are traditionally made using complex manufacturing processes or expensive electronic circuits.

  The device according to the invention makes it possible to produce a simpler measuring instrument, since it is composed of only two needles in a transparent and graduated case. The transparency of the case underlines the simplicity of the instrument and offers it a current design.

  According to a first characteristic, the device according to the invention comprises a laminate composed of two materials of different thermal expansion for the thermometer and a laminate composed of a plastic or metallic layer on a hygroscopic layer for the hygrometer.

  In the case of FIG. 1, the thermal laminated needle (l) consists of a layer of aluminum 11 micrometers thick (standard household aluminum foil) fixed to a layer of adhesive PVC thickness 50 micrometers (standard transparent adhesive tape, schoolboy type adhesive), length 63 millimeters and width approximately 6 millimeters.

  -The hygrometric laminated needle consists of a layer of aluminum thickness 25 11 micrometers (household aluminum foil, standard) glued with liquid neoprene to a layer of paper 0.10 millimeter thick (block paper standard note) of length 40 millimeters and width approximately 7 millimeters.

  In the case of the hygrometric needle (9, the sheets 30 of paper have a direction of deformation which must be known before creating the laminate. The length of the needle is cut in the longitudinal direction of the sheet of notepad .

  To find out the direction of deformation of any sheet, simply cut a longitudinal strip and a transverse strip (write "LONGITUDINAL" or "TRANS VERSAL" above). Then apply an adhesive strip to each strip. The two strips are immersed in a container of water. One of the two strips instantly deforms and indicates the correct direction of cutting.

  The two needles QD and QC are fixed with double-sided adhesive with a common Plexiglas base 3. A rubber bond (thickness 0.5mil3imeter absorbs deformations of the hygrometric needle (2 in the extreme position. The colored arrowsO (blue for the hygrometer and red for the thermometer) are made of paper of approximate thickness 0, 2 millimeters and are glued to the ends of the needles. By way of non-limiting example, it is possible to use plexiglass thickness 2, 3 millimeters for the housing 4, with air inlets (s5.

  The graduation of the hygrometer is done directly on the front face of the case and on the rear face for the thermometer (see figure 2). The reverse is possible.

  To have a wider graduation (see Figure 3) and a lower amplitude of the thermometric needle, the adhesive PVC layer must be doubled (ie 100ym instead of 50, um).

  The commercial presentation will be made in waterproof plastic, to avoid untimely curvatures linked to hygrometric variations of the ambient air and to solar exposures.

  The device according to the invention is particularly designed to measure (with increased visual comfort), the temperature and the humidity of the ambient air in an original and decorative manner.

Claims (6)

  1) Thermometer-hygrometer with dial needles curving as a function of the temperature and humidity of the ambient air, characterized in that these needles consist of a laminate composed of a layer of low thermal expansion / high thermal expansion layer for the thermometer and a laminate composed of a metal layer / hygroscopic layer or an adhesive plastic / hygroscopic layer for the hygrometer.   2) thermometer-hygrometer according to claim 1, ca10 characterized in that the laminate (consists of an aluminum layer of thickness between 2 micrometers and 1 millimeter, glued or fixed to a layer of PVC between 10 micrometers and 1 millimeter, and the laminate O consists of a layer of aluminum with a thickness between 2 micro15 meters and 1 millimeter glued or fixed to a layer of paper with a thickness between 20 micrometers and 1 millimeter.   3) Thermometer-hygrometer according to claim 1 or claim 2, characterized in that the laminated needles are fixed or glued to the base of a rigid case D 20 with air inlet and outlet, and wall fixing hole C.   4) Thermometer-hygrometer according to claim 3, characterized in that a rubber connection Q is located between the hygrometric needle QO and the fixing base Q on the housing.   5) Thermometer-hygrometer according to the preceding claims, characterized in that the housing U. is transparent and graduated.   6) Thermometer-hygfometer according to the preceding claims, characterized in that the laminated needles are terminated by an arrow 6 made of thick and colored paper.