SU922607A1 - Method of structure material thermal physical characteristic determination - Google Patents

Description

(54) DEVICE FOR DETERMINATION OF THERMOPHYSICAL CHARACTERISTICS OF MATERIALS OF CONSTRUCTIONS

one

The invention relates to the determination of the thermophysical characteristics (thermal conductivity, thermal diffusivity, heat capacity) of capillary-porous wet building materials.

Devices are known for determining the thermophysical characteristics of materials, comprising a flat heater, a temperature sensor, a reference body, a heating source, and a measuring device for recording temperature 1.

The disadvantage of these devices is the need to locate a temperature sensor inside the construction material, which does not allow to determine the desired characteristics without disturbing the integrity of the construction material.

The closest to the present invention is a device for determining the thermophysical characteristics of materials of construction, which, in addition to a flat heater with a temperature sensor placed in the plane of the heater, a reference body, a heat source and a measuring device for temperature, is equipped with an additional flat electrode located coplanarly with the heater at the same time, the second electrode, which, together with the additional electrode, forms a capacitive wet volume sensor 10 ti 21.

However, the device does not allow the thermophysical characteristics of the materials of the structures to be determined in a non-destructive way if it contains

15 facing layer.

The purpose of the invention is to expand the functionality of the device.

Claims (2)

The goal is achieved by the fact that a device for determining the heat 20 physical characteristics of materials of construction, containing a flat heater with a temperature sensor placed in the plane of the heater, an external electrode, a computer located with a heater, which serves as a simultaneous internal electrode, which together form a capacitive sensor of volumetric humidity connected to the capacitance meter, heat source and temperature recorder, provided with an additional flat ring electrode located between The external and external electrodes of the capacitive sensor are such that the distance between the middle circumferences of the external electrode and the additional electrode is commensurate with the thickness of the finishing material and relates to the distance between the average circumference of the external electrode as well as the thickness of the separating layer to the total thickness of the construction material The electrodes of the capacitive sensor simultaneously serve as elements of the heater, having equal electrical resistance per unit area. In addition, the device is equipped with a multi-channel switch connected to the elements of the heater and a heat source. FIG. 1 shows a block diagram of the proposed device; in fig. 2 is an example of a structural embodiment of an electrode heating system. The device contains an internal (high-potential) electrode 1, an additional (high-potential) electrode 2 and an external (low-potential) electrode 3 forming a three-electrode capacitive humidity sensor and simultaneously serving as heater elements, one of which has a temperature sensor (thermocouple). The electrodes of the capacitive sensor (heating elements) are fixed on the base 5, which is the reference body, and connected to the capacitance meter 6 and, simultaneously, via the multi-channel switch 7 with the source 8 of the pulse heating. The temperature sensor is connected to the temperature meter 9. In order to determine the thermophysical characteristics of the electrode heater, the device system is brought into contact with the surface of the structure under study. The device works as follows. In the initial state, the switch 7 is set to the heating position. When you turn on the source 8 of the pulse heating, the heat pulse arrives at the elements of the heater 1-3; connected in series and transmitted to the surface of the structure under study. Since the elements of the heater are designed in such a way that they have equal electrical resistance per unit area, the specific heat flux over the entire working surface of the electrode-heating system has the same value. After applying the heat pulse, the switch 7 is set to the measurement position. At the same time, connecting lines connecting them with each other and with a heating source are disconnected from the heater elements, and electrodes 1-3 are connected to a capacitance meter 6, the readings of which are proportional to the volumetric moisture of the construction material. The recording of the temperature of the heater is performed continuously or discretely according to the indications of the temperature meter 9 to which the temperature sensor A is connected. The proposed device is widely used in the production quality control of finished products in construction industry enterprises and in field studies of enclosing structures of buildings and structures. Claim 1, Apparatus for determining the thermophysical xapaKj-structural materials of structures, comprising a flat heater with a temperature sensor placed in the plane of the heater, an outer electrode located coplanar with the heater, simultaneously serving as an internal electrode, which together form a capacitive volumetric humidity sensor connected to the meter tanks, a heat source and a temperature recorder, differently in that, in order to expand its functionality, it is equipped with tively flat annular electrode disposed between the inner and outer electrodes succinctly stnogo sensor so that the distance between the middle and outer circumferences of the additional electrodes is comparable to the thickness of the material layer 5chtsogo separated and relates to the distance between the mean circumference the outer electrode is the same as the thickness of the finishing layer to the total thickness of the material of construction, and all the electrodes of the capacitive sensor simultaneously serve as elements of the heater, having equal electrical resistance per unit area. , 2. The device according to claim 1, characterized in that it includes a multi-channel switch connected to the elements of the heater and the heating source. Sources of information taken into account in the examination 1, Dmitrovich A.D. Determination of thermophysical properties of building materials, M., stroiizdat, 19bZ, p. 91 108. 2. USSR author's certificate number 800846, cl. G 01 N 25/18, 1979 (prototype).