RU74712U1 - DEVICE FOR MEASURING SPECIFIC RESISTANCE OF HEAT TRANSFER THROUGH THE OBJECT - Google Patents

Abstract

1. A device for measuring resistivity to heat transfer through an object containing a heat exchanger, an inlet pipe, an outlet pipe, a first contact temperature meter, a second contact temperature meter, thermal insulation, the outer surface of the heat exchanger is provided with thermal insulation except for the outer surface of the heat exchanger adjacent to the inner surface of the test object, the exchanger output is connected to the inlet of the outlet pipe, the first contact temperature meter is located between the inner surface of the test object and the outer surface of the heat exchanger, characterized in that it further comprises a heating tank, connecting pipe, storage tank, drain tank, the heating tank is equipped with a heating element and a drain pipe, the connecting pipe is equipped with a valve and a flow meter, the inlet pipe is equipped valve and flow rate meter, the drain pipe is equipped with a valve and flow rate meter, input output pipe is connected to the inlet of the heating tank, the output of the heating tank is connected to the input of the connecting pipe, the output of the connecting pipe is connected to the input of the heat exchanger, the output of the storage tank is connected to the input of the input pipe, the output of the output pipe is connected to the first inlet of the drain tank, and the output of the drain pipe is connected to the second inlet of the drain tank. 2. The device according to claim 1, characterized in that it further comprises a third contact located in the connecting pipe

Description

The utility model relates to construction equipment and can be mainly used to measure the thermal values of various building structures, for example, walls, ceilings, floors, bulkheads, ceilings, etc.

A device for drilling wells [1], which allows to obtain samples of materials from various depths. By measuring the parameters of these samples, one can obtain information on the physical and chemical properties and configuration of the deep layers. A disadvantage of the known device is that it does not provide non-destructive testing of the investigated object

Numerous versions of devices for ultrasonic flaw detection are known, for example, [2, 3], which make it possible to determine the presence of inhomogeneities in various structures and the configuration of these inhomogeneities, however, devices of this kind do not allow the measurement of thermophysical quantities of the materials under study, in particular, thermal resistance.

Numerous variants of devices for measuring the thermal resistance of various electronic devices are known, for example, a device for measuring the thermal resistance of transistors described in [4]. A disadvantage of the known technical solution lies in a narrow scope: it can only be used to measure the thermal resistance of transistors.

Known is described in [5] a device for determining the characteristics of materials containing a source of pulsed heating, a thermocouple

and an electronic processing unit. A thermocouple is located on the surface of the test sample. The output of the thermocouple is connected to the input of the electronic processing unit. The main disadvantage of the known device is that when using pulsed heating requires complex processing of the measurement results, which requires sophisticated equipment. This leads to a significant increase in the cost of measurements. In addition, the great complexity of processing the measurement results leads to a decrease in their accuracy and reliability.

The closest in technical essence to the claimed technical solution is a device for measuring the thermophysical characteristics [6], comprising a heat exchanger, an inlet pipe, an outlet pipe, two contact temperature meters, thermal insulation, the outer surface of the heat exchanger is provided with thermal insulation except for the external adjacent to the inner surface of the studied object the surface of the heat exchanger, the output of the heat exchanger is connected to the inlet of the outlet pipe, the first contact meter tempe Aturi disposed between the inner surface of the test object and the outer surface of the heat exchanger. The second contact temperature meter is placed either on the outer surface of the test object, or on the side surface of the test object.

The known device has low consumer properties. This is due to the need to maintain a constant mass flow rate of the coolant [kg / s] and constant temperature of the coolant at the inlet of the heat exchanger to ensure high accuracy and high reliability of measurements. If these parameters of the coolant are unstable in time, the known device does not allow to achieve high accuracy and high reliability of measurements, as a result of which consumer properties turn out to be low.

The objective of the utility model is to increase consumer properties by increasing the accuracy and reliability of measurements.

The solution of the problem in accordance with claim 1 of the utility model is ensured by the fact that in a known device comprising a heat exchanger, an inlet pipe, an outlet pipe, a first contact temperature meter, a second contact temperature meter, thermal insulation, the outer surface of the heat exchanger is provided with thermal insulation except adjacent to the inner surface of the object under study the outer surface of the heat exchanger, the output of the heat exchanger is connected to the inlet of the output pipe, the first contact The temperature meter is located between the inner surface of the test object and the outer surface of the heat exchanger, the following improvements are made: it additionally contains a heating tank, a connecting pipe, a storage tank, a drain tank, a heating tank equipped with a heating element and a drain pipe, a connecting pipe is equipped with a valve and a coolant flow meter , the inlet pipe is equipped with a valve and a coolant flow meter, the drain pipe is equipped with with a heat carrier flow meter and meter, the output of the input pipe is connected to the input of the heating tank, the output of the heating tank is connected to the input of the connecting pipe, the output of the connecting pipe is connected to the input of the heat exchanger, the output of the storage tank is connected to the input of the input pipe, the output of the output pipe is connected to the first input of the drain tank and the outlet of the drain pipe is connected to the second inlet of the drain tank.

The use in the inventive device of a heating tank equipped with a heating element, provides a constant in time temperature of the coolant at the inlet of the heat exchanger and the constancy

in time, the mass flow rate of the coolant in the heat exchanger. The valves allow you to adjust the mass flow rate of the coolant passing through the corresponding pipelines. In the process of establishing the operating mode, the coolant passes through the drain pipe, bypassing the heat exchanger. The valve of the connecting pipe is opened only after the coolant is heated to the required temperature, while the valve of the drain pipe is closed. Thus, from the moment the measurements are started, the coolant enters the heat exchanger inlet, the mass flow rate of which and the temperature are constant in time, as a result of which the accuracy and reliability of the measurements are increased. This leads to an increase in consumer properties of the claimed device compared to the prototype.

We show that the problem of the utility model is solved in the claimed technical solution.

To do this, we consider the physical and mathematical models of the process and the algorithm for processing the measurement results.

The physical model of the object under study — a single-layer wall (as a fragment of the enclosing structure) —can be represented as a uniform unlimited plate with a thickness of L [m]. At the initial time, the inner surface of the plate is brought into contact with a heat exchanger with a temperature t _c1 [K].

We introduce the following restrictions:

1. The thermal inertia of the heat exchanger is so small in comparison with the thermal inertia of the studied object that it can be neglected.

2. The temperature of the heat exchanger from the beginning to the end of the process remains unchanged.

3. The initial temperature of the investigated object is uniformly distributed over its volume and is equal to the ambient temperature.

4. The length of the heat exchanger along the inner surface of the test object is much greater than the thickness of the test object.

These restrictions are best satisfied by the flow-through heat exchanger, whose thermal inertia is much less than the thermal inertia of the object under study. We also introduce the following assumptions:

1. The heat flux through the object under study is one-dimensional and uniform in cross section.

2. The thermophysical parameters of the material of the studied object does not depend on temperature.

3. The contact coefficient of heat transfer from the heat exchanger to the inner surface of the test object remains unchanged at any time.

4. Until the completion of the first stage of the unsteady thermal regime, the external, opposite to the heated, surface of the studied object can be considered insulated. We assume that the time of the initial stage of heating has arrived if the temperature on the outer surface of the test object is t = t ₀ + Δt ₃ , where 0.5 K ≤Δt ₃ ≤2 K; t ₃ - set value of overheating. This range of changes of L1z will correspond to its own range of values of the Fourier number Fo ₁ = Fo (Δt ₃ ). The choice of the range corresponds to the sensitivity of the applied temperature measurement technique.

By measuring the duration of the initial stage of heating g-i experimentally, it is possible to determine the specific resistance to heat transfer (which is also called the specific thermal resistance) of the studied object through thermal diffusivity according to the formula:

where r is the specific thermal resistance of the object, m ² K / W; λ is the coefficient of thermal conductivity of the material of the object, W / mK; L is the thickness of the flat layer of the investigated object, m; With ₀ - volumetric heat capacity of the material of the object, J / m ³ K; a is the thermal diffusivity of the material of the object, m ² / s, Fo ₁ is the characteristic value of the criterion Fourier number corresponding to time τ ₁ .

Computational studies of the duration of the process were carried out taking into account the influence of the main determining parameters. These studies were supplemented by numerical calculations that take into account the thermal inertia of the heat exchanger.

The algorithm for measuring the thermal diffusivity is based on the fact that the time required for heating the test object to the external surface is related to the thermal diffusivity of the test object through the criterion number Fo. The value of the criterion number Foi, which relates the depth of heating of the material layer with the heating time to the specified value At, can be determined on the basis of calculation by an analytical or numerical method.

Dependence

at Bi> 100 it is universal. The temperature head on the heat exchanger ϑ ₀ is set by the power of the heating element in the heating tank, and the temperature superheat Δt is measured. Thus, by measuring the duration of the initial stage of heating τ ₁ experimentally, it is possible to determine the thermal diffusivity by the formula (1). To the greatest extent, the convenience of practical use of the claimed technical solution can be realized in the case of obtaining an approximation

Descriptions of the dependence of Fo ₁ on ϑ ₀ and Δt in the form of an analytical formula.

In the interval of change Δt (0.5-2.0) K, dependence (2) is approximated in the form:

Where

It is more convenient to represent dependence (3) for practical calculations in a dimensionless form

where ϑ _m is the characteristic value of the temperature head, taken equal to ϑ _m 100K.

The quality criterion for the final approximation dependence (4) is the approximation error 5, which is calculated by the formula:

where Fo ^A are the values of Fo ₁ obtained from the exact solution; Fo ^a - values

Fo ₁ calculated according to (4).

The results of the analysis of the errors of dependence (4) are presented in table 1.

Table 1 Approximation error δ% ΔtK θ ₀ K 80 70 60 fifty 40 thirty twenty 0.5 -1.2 -1.5 -1.7 -1.9 -2.0 -1.8 -1.1 one 2.1 1.8 1,5 1.3 1,1 1.3 2.2 1,5 1,6 1,2 0.8 0.5 0.3 0.4 1.7 2 -0.2 -0.6 -1.1 -1.5 -1.7 -1.4 0.2

As can be seen from the data in Table 1, the approximation formula (4) provides the accuracy of calculations that is quite satisfactory for practice.

However, approximation formula (4) was obtained under the assumption of instantaneous creation of overheating on the heated surface of the studied object. In practice, without taking special measures, such a restriction on the instantaneous occurrence of temperature pressure on the heated surface of the investigated object is not implemented. This is due to the thermal inertia of the heat exchanger and heating device, which ensures the heating of water to a predetermined temperature. Consider the influence of these factors on the instantaneous heating of the surface of the investigated object.

We will take into account the thermal inertia of the heat exchanger. Consider the situation when the heat exchanger is in contact with the measured sample and has the same initial temperature, and its heating begins at the moment of the start of the flow of coolant to its input with the initial temperature To. Then the change in temperature of the heat exchanger over time can be described as follows [7]

where t ₁ is the temperature of the inner surface of the investigated object in contact with the working surface of the heat exchanger [K]; t _{0 -} water temperature at the inlet of the heat exchanger [K]; - thermal conductivity between the working surface of the heat exchanger and the inner surface of the test object [W / K]; C _w is the total heat capacity of the heat exchanger together with the pipeline [J / K]; S is the surface area of the pipeline [m ² ]; α is the heat transfer coefficient of the coolant with the inner surface of the pipeline [W / m ² ] K]; M - mass flow rate of the coolant [kg / s]; c _f is the specific heat of the coolant [J / kgK]

At the initial moment of time τ = 0, the temperatures of the heat exchanger and the heated surface of the test object are equal to the initial temperature or the temperature of the medium, that is, t _T = t ₁ = t _c . Exit to the stationary thermal regime is carried out at τ> 4 / m ₀ , that is, to heat the inner surface of the investigated object, it is necessary to spend a certain time, which requires evaluation. The neglect of this time leads to a systematic error in determining the time τ spent on through heating of the object under study. This, in turn, will introduce a systematic error in determining the coefficient of thermal diffusivity.

The relative error in determining the coefficient of thermal diffusivity is calculated as follows. For the selected nominal value of the thermal diffusivity coefficient, Δt (τ ₂ ) is calculated taking into account the formula (6), where τ _{2 is the} time of occurrence of overheating taking into account the thermal inertia of the heating heat exchanger. This value is greater than τ, and in the limiting case of zero thermal inertia of the heat exchanger coincides with it. Then you can write

where a _{2 is the} value of a, determined taking into account the time taken to heat the heat exchanger to a stationary temperature. The relative error is determined by the formula

Consider the system "heat exchanger - the studied object." To calculate a _2, it is necessary to pose a boundary-value problem of thermal conductivity with a boundary condition of the first kind on a heated surface and the condition of thermal insulation on the opposite surface.

We write the heat equation in the form

with boundary conditions:

and the initial condition:

In this case, the boundary conditions on the heated surface will include the temperature of the heat exchanger, determined by formula (6), and t ₁ is the temperature of the heated inner surface of the object under study.

In such a formulation, the problem is very difficult to use analytical approaches. Therefore, the calculations were performed numerically, using the finite-difference scheme constructed by the integro-interpolation method [8]. The time was fixed at which the temperature of the thermally insulated surface began to change, as well as the time during which this change occurred in the range from 0.5 to 2 ° C. Further, based on the values of this change and the temperature head on the heated surface, the criterion Fourier number Fo _{2 was} calculated by the formula (4). Then, a _{2 was} calculated from (7), and from (8) using the nominal value of thermal diffusivity - δa ₂ .

The results are presented in figure 1 and figure 2.

Figure 1 shows graphs of the dependence of the relative error in determining the coefficient of thermal diffusivity of a flat test object with a thickness of 0.3 m due to the delay in establishing the stationary temperature of the heat exchanger heated to the operating temperature by the heat carrier from the measured overheating on the opposite surface of the test object. The nominal values of the coefficient of thermal diffusivity are equal (m ² / s, 10 ^-6 ): 0.9 (line L ₁ ); 0.3 (line L ₂ ); 0.15 (line L ₃ ). The temperature of the coolant at the inlet to the heat exchanger ϑ ₀ = 80 K, its mass flow rate M = 5 g / s.

Figure 2 shows graphs of the dependence of the relative error in determining the coefficient of thermal diffusivity of a flat test object with a thickness of 0.3 m due to the delay in heating by the hot heat carrier of the heat exchanger, brought into contact with the inner surface of the test object, from the measured overheating on the outer surface of the test object. Nominal values of the coefficient of thermal diffusivity are equal, (m ² / s, 10 ^-6 ): 0.9 (line L ₄ ); 0.3 (line L ₅ ); 0.15 (line L ₆ ). The temperature of the coolant at the inlet to the heat exchanger ϑ ₀ = 50 K, its mass flow rate M = 5 g / s.

In many cases, such an error is quite acceptable. However, the problem is aggravated by the fact that the heat carrier can be supplied to the heat exchanger inlet from the heater, which changes its temperature even more slowly than the heat exchanger heats up when the heat exchanger with its predetermined operating temperature is supplied to its heat exchanger. Changing the temperature of the coolant supplied to the input of the heat exchanger requires an analysis of the thermal inertia of the heater.

We will take into account the thermal inertia of the heat exchanger and heater. When deriving formula (6), it was assumed that the coolant enters the heat exchanger inlet immediately warmed up to temperature t ₀ . However, the heater has thermal inertia. To enter the operating mode, in which the coolant leaves it heated up to a given temperature t ₀ , time is required. Consider the effect of thermal inertia of the heater on the measurement process.

Consider that the coolant moves sequentially through the heater, and then through the heat exchanger in contact with the test object. This means that the mass flow rate of the coolant M and the heat capacity of the coolant C _f will be the same in the mathematical model considered below, which are included in relation (6).

We assume that the heater is made in the form of a heating tank equipped with a heating element, which transfers thermal energy to the coolant flowing through it. Then the non-stationary volumetric average temperature of the heated heat exchanger will be described by a linear differential equation of the first order of the form

Under the initial condition

where C _k is the total heat capacity of the heat exchanger together with the pipeline [J / K]; t _k is the temperature of the heated heat exchanger [° C]; t _in - the temperature of the coolant at the inlet to the heat exchanger [° C]; _k is the thermal conductivity from the heated heat exchanger to the environment [W / K];

P is the heat dissipation power of the heating element [W].

The solution of equation (13) has the form

where α _k is the convective heat transfer coefficient [W / m ² K]; S _k is the surface area of the heat exchanger [m ² ].

We take into account the small thermal inertia of the coolant. Then the distribution of the coolant along the length of the pipeline is described by a differential equation of the first order:

where L _k is the length of the heated body of the heat exchanger (or pipeline).

The solution of equation (16) has the form

From (17) it follows that the temperature of the water leaving the heater is

Substituting in (18) the expressions for t _k from (15), we obtain:

At the initial moment:

In stationary mode:

We introduce the restriction: t _BX = t _c s, which means that the temperature of the heat exchanger at the heater inlet is equal to the ambient temperature. Then, expanding the expression for Ek, we obtain after transformations from (19):

We introduce one more restriction. E _k = 1 (condition for complete recovery). Then the expression (22) will be simplified to the form:

Now compare the thermal inertia of the heater and the heat exchanger. While ensuring good thermal contact of the heat exchanger with the test object, the condition must be ensured:

at which the formula in (6) for the tempo then simplifies to the form

For the heater to work efficiently, the heat loss to the environment must be small. For this, the thermal conductivity of the insulation should be much less than the water equivalent, which is described by the inequality:

where from

From the structure of formulas (25) and (27), taking into account condition (24), we obtain

Inequality (28) means that the values of thermal inertia constants, which are the reciprocal of the heating rate, are in opposite proportions, i.e., the thermal inertia of the heater is much greater than the thermal inertia of the heat exchanger. This means that the time taken to heat the coolant with the heater to a predetermined temperature t ₀ will be much longer than the time required to heat the heat exchanger (and, accordingly, the surface of the layer adjacent to it) to t ₁ .

This will lead to a further significant increase in the thermal diffusivity determination error.

Thus, the task of the utility model is really solved in the claimed technical solution.

In the particular case, in accordance with claim 2 of the utility model formula, the claimed device further comprises a third contact temperature meter located in the connecting pipe. The presence of this contact temperature meter allows you to get more complete information about the heat transfer process, resulting in increased accuracy and reliability of measurements.

In the particular case, in accordance with paragraph 3 of the formula of the utility model, the claimed device further comprises a fourth contact temperature meter located in the outlet pipe. The presence of this contact temperature meter allows you to get more complete information about the heat transfer process, resulting in increased accuracy and reliability of measurements.

In the particular case, in accordance with paragraph 4 of the utility model formula, a second contact temperature meter is located on the outer surface of the object under study. This embodiment of the inventive device provides a fixation of the start time of the temperature rise at a given point located on the outer surface of the investigated object.

In the particular case, in accordance with paragraph 5 of the utility model formula, a second contact temperature meter is located on the side surface of the object under study. This embodiment of the inventive device provides a fixation of the start time of the temperature rise at a given point located on the side surface of the investigated object.

In the particular case, in accordance with paragraph 6 of the formula of the utility model, the storage tank is made adjustable in height. This embodiment of the claimed device allows, if necessary, changing the pressure of the coolant at the inlet of the heat exchanger, as a result of which it is possible to change the mass flow rate of the coolant in the heat exchanger depending on the specific measurement conditions.

In a particular case, in accordance with paragraph 7 of the utility model formula, the storage tank is equipped with an overflow pipe, the outlet of which is connected to the third inlet of the drain tank. If the position of the storage tank in height is unchanged and the parameters of the claimed device are selected in such a way that the mass flow rate of the coolant in the connecting pipe is less than the minimum possible mass flow rate of the coolant in the inlet pipe, then part of the coolant goes all the way through the overflow pipe, as a result of which constant coolant level in the storage tank. This leads to a constant value of the mass flow rate of the coolant in the heat exchanger, resulting in increased accuracy and reliability of measurements.

In the particular case, in accordance with paragraph 8 of the utility model formula, the claimed device further comprises an external pipeline, the storage tank is equipped with a coolant level meter, the external pipe is equipped with a valve, the control input of which is connected to the output of the coolant level meter. If the position of the storage tank in height is unchanged and the parameters of the claimed device are selected so that the mass flow rate of the coolant in the connecting pipe is less than the minimum possible mass flow rate of the coolant in the inlet pipe, then the coolant level sensor generates a signal to the control input of the valve, which an external pipeline is provided, as a result of which a constant level of coolant in the storage tank is ensured. This leads to a constant value of the mass flow rate of the coolant in the heat exchanger, resulting in increased accuracy and reliability of measurements.

The essence of the utility model is illustrated by a description of two specific options for the structural implementation of the claimed device and drawings, in which:

- figure 1 - figure 2 shows graphs explaining the essence of the utility model,

- figure 3 shows a diagram of a first embodiment of a structural embodiment of the claimed device,

- figure 4 shows a diagram of a second embodiment of a structural embodiment of the claimed device.

The first embodiment of the device for measuring the specific resistance to heat transfer through the object comprises a heat exchanger 1, an inlet pipe 2, an outlet pipe 3, a first contact temperature meter 4, a second contact temperature meter 5, thermal insulation 6, the outer surface of the heat exchanger 1 is provided with thermal insulation 6 except adjacent to the inner surface 7 of the test object 8 of the outer surface of the heat exchanger 1, the output of the heat exchanger 1 is connected to the input of the output pipe 3, ne A contact temperature meter 4 is placed between the inner surface 7 of the test object 8 and the outer surface of the heat exchanger 1. It also contains a heating tank 9, a connecting pipe 10, a storage tank 11, a drain tank 12, a heating tank 9 is equipped with a heating element and a drain pipe 13, connecting the pipeline 10 is equipped with a valve 14 and a flow meter 15, the inlet pipe is provided with a valve 16 and a flow meter 17, the drain pipe 13 is equipped with a valve 18 and and coolant flow meter 19, the output of the input pipe 2 is connected to the input of the heating tank 9, the output of the heating tank 9 is connected to the input of the connecting pipe 10, the output of the connecting pipe 10 is connected to the input of the heat exchanger 1, the output of the storage tank 11 is connected to the input of the input pipe 2, the output pipe 3 is connected to the first inlet of the drain tank 12, and the output of the drain pipe 13 is connected to the second inlet of the drain tank 12. The third contact temperature meter 20 is located in the flax pipe 10, the fourth contact temperature meter 21 is located in the outlet pipe 3.

The second contact temperature meter 5 is located on the outer surface 22 of the test object 8 or on the side surface 23 of the test object 8.

As a heating element, a converter of electric energy into thermal energy can be used. The terminals to which an external source of electrical energy is connected are indicated by 24 in FIGS. 3 and 4. The direction of flow of the heat carrier is shown by arrows indicated by 25 at FIGS. 3 and 4. The storage tank 11 is equipped with an overflow pipe 26, the outlet of which connected to the third inlet of the drain tank 12.

The change in pressure of the coolant at the inlet of the heat exchanger 1 is carried out by changing the height of the storage tank 11 above the heat exchanger 1 (by changing the value of h).

The coolant accumulated in the drain tank 12 can be used again by transporting it from the drain tank 12 to the storage tank 11 using a return pipe 27 provided with a valve 28 and pump 29 or by transporting the coolant from the drain tank 12 to the storage tank 11 using any containers, for example, buckets.

The described embodiment of the structural implementation of the claimed device operates as follows. At the initial moment of time, valves 16, 18, and 28 are opened and the heating element and pump 29 are turned on. The valve 14 must be closed. The heat carrier from the storage tank 11 enters the heating tank 9 through the inlet pipe 2. The excess coolant received through the storage tank 11 overflow pipe 26 enters the drain tank 12 (this maintains a constant level of coolant in the storage tank 11). The heating element heats the heat carrier located in the heating tank 9. From the heating tank 9, the coolant through the drain pipe 13 enters the second inlet of the drain tank 12. From the drain tank 12, the coolant by means of the pump 29 enters the storage tank 11, after which the process is repeated. While the temperature of the coolant is lower than the required value, the valve 14 is closed. When the temperature of the coolant in the heating tank 9 reaches the desired value, open the valve 14 and close the valve 18, after which the coolant through the connecting pipe 10 enters the heat exchanger 1. The working temperature of the coolant at the inlet of the heat exchanger 1 should to be higher than the maximum possible temperature of the coolant at the inlet of the heating tank 9. When the temperature of the coolant entering the inlet pipe 2 changes, the constancy the temperature at the inlet of the heat exchanger 1 is provided by changing the operating mode of the heating element. In the heat exchanger 1, the heat carrier transfers thermal energy to the test object 8 through a portion of the inner surface 7 of the test object 8 adjacent to the outer surface of the heat exchanger 1. The first (third, fourth) contact temperature meter 4 (20, 21) records the moment the temperature rises and its further change in time in the contact area of the outer surface of the heat exchanger 1 with the inner surface 7 of the test object 8 (in the connecting pipe 10, in the output pipe 3). The second contact temperature meter 5 captures the moment the temperature rises and its further change in time at a given point. In accordance with paragraph 4 of the utility model formula, the target point is selected on the outer surface 22 of the test object 8. In accordance with paragraph 5 of the utility model formula, the target point is selected on the side surface 23 of the test object 8. The heat carrier passing through the heat exchanger 1 flows through the outlet pipe 3 to the first inlet of the drain tank 12. The flow rate meters 15, 17 and 19 of the coolant control the flow rate of the coolant in the connecting pipe 10, the inlet pipe 2 and the drain pipe 13. The working temperature of the coolant the spruce at the inlet of the heat exchanger 1 should be higher than the maximum possible temperature of the coolant at the inlet of the heating tank 9. When the temperature of the coolant entering the inlet pipe 2 changes, the temperature at the inlet of the heat exchanger 1 is constant due to a change in the operating mode of the heating element.

Calculation of the thermal values of the studied object is carried out according to the known method described, for example, in [6].

The second embodiment of the device for measuring the specific resistance to heat transfer through the object contains an external pipe 30 provided with a valve 31 and a pump 29, the storage tank 11 is equipped with a level meter 32 of the coolant, the output of which is connected to the control inputs of the valve 31 and the pump 29. The outer surface of the heat exchanger 1 is provided thermal insulation 6 in addition to adjacent to the inner surface 7 of the test object 8, the outer surface of the heat exchanger 1, the output of the heat exchanger 1 is connected to the input of the output about pipeline 3, the first contact temperature meter 4 is placed between the inner surface 7 of the test object 8 and the outer surface of the heat exchanger 1. The heating tank 9 is equipped with a heating element, the connecting pipe 10 is equipped with a valve 14 and a flow meter 15, the inlet pipe 2 is equipped with a valve 16 and a meter flow rate of the coolant 17, the drain pipe 13 is equipped with a valve 18 and a flow meter of the coolant 19, the output of the inlet pipe 2 is connected to the input of the heating tank 9, you One of the heating tank 9 is connected to the input of the connecting pipe 10, the output of the connecting pipe 10 is connected to the input of the heat exchanger 1, the output of the storage tank 11 is connected to the input of the input pipe 2, the output of the output pipe 3 is connected to the first input of the drain tank 12, and the output of the drain pipe 13 is connected with the second inlet of the drain tank 12. The third contact temperature meter 20 is located in the connecting pipe 10, the fourth contact temperature meter 21 is located in the outlet pipe 3.

The second contact temperature meter 5 is located on the outer surface 22 of the test object 8 or on the side surface 23 of the test object 8.

As a heating element, a converter of electric energy into thermal energy can be used.

The change in pressure of the coolant at the inlet of the heat exchanger 1 is carried out by changing the height of the storage tank 11 above the heat exchanger 1 (by changing the value of h).

The coolant accumulated in the drain tank 12 can be reused by transporting it from the drain tank 12 to the storage tank 11 using an external pipe 30 provided with a pump 29 and valve 31, the inlet of which is connected to the outlet of the drain tank 12, or by transporting the coolant from the drain tank 12 into external pipeline 30 using any containers, for example, buckets.

The described embodiment of the structural implementation of the claimed device operates as follows. At the initial moment of time, valves 16, 18 and 31 are opened and the heating element and pump 29 are turned on. The valve 14 must be closed. The heat carrier from the storage tank 11 enters the heating tank 9 through the inlet pipe 2. The heating element heats the heat carrier located in the heating tank 9. The level meter of the coolant 32 generates a signal supplied to the control inputs of the pump 29 and valve 31, while the level of coolant in the storage tank 11 is maintained constant.

From the heating tank 9, the coolant through the drain pipe 13 enters the second inlet of the drain tank 12. From the drain tank 12, the coolant using the pump 29 enters through the external pipe 30 into the storage tank 11, after which the process is repeated. While the temperature of the coolant is lower than the required value, the valve 14 is closed. When the temperature of the coolant in the heating tank 9 reaches the desired value, open the valve 14 and close the valve 18, after which the coolant through the connecting pipe 10 enters the heat exchanger 1. The working temperature of the coolant at the inlet of the heat exchanger 1 should to be higher than the maximum possible temperature of the coolant at the inlet of the heating tank 9. When the temperature of the coolant entering the inlet pipe 2 changes, the constancy the temperature at the inlet of the heat exchanger 1 is provided by changing the operating mode of the heating element. In the heat exchanger 1, the heat carrier transfers thermal energy to the test object 8 through a portion of the inner surface 7 of the test object 8 adjacent to the outer surface of the heat exchanger 1. The first (third, fourth) contact temperature meter 4 (20, 21) records the moment the temperature rises and its further change in time in the contact area of the outer surface of the heat exchanger 1 with the inner surface 7 of the test object 8 (in the connecting pipe 10, in the output pipe 3). The second contact temperature meter 5 captures the moment the temperature rises and its further change in time at a given point. In accordance with Clause 4 of the utility model formula, the set point is selected on the outer surface 22 of the test object 8. In accordance with Clause 5 of the utility model formula, the set point is selected on the side surface 23 of the test object 8. The heat carrier passing through the heat exchanger 1 flows through the outlet pipe 3 to the first inlet of the drain tank 12. The flow rate meters 15, 17 and 19 of the coolant control the flow of coolant in the connecting pipe 10, the inlet pipe 2 and the drain pipe 13, respectively.

The coolant level sensor 32 generates a signal arriving at the control inputs of the pump 29 and valve 31, ensuring a constant level of the coolant in the storage tank 11. The working temperature of the coolant at the inlet of the heat exchanger 1 should be higher than the maximum possible temperature of the coolant at the inlet of the heating tank 9. When the temperature of the incoming in the inlet pipe 2 of the coolant the constancy of the temperature of the coolant at the inlet of the heat exchanger 1 is provided by changing the operating mode of the heat flax element.

Calculation of the thermal values of the studied object is carried out according to the known method described, for example, in [6].

INFORMATION SOURCES

1. Sukhov R.I., Lebedkin Yu.M., Kuznetsov V.G. and others. A method of drilling wells and a device for its implementation. RF patent for invention No. 2237148, prior. 1999.10.06, publ. 2001.07.20, IPC7 Е21В 6/02, Е21В 7/00, Е21В 10/36.

2. Pilin B.P., Markov A.A., Molotkov S.L. The method of ultrasonic inspection and a device that implements it. RF patent for the invention No. 2131123, prior. 1996.01.12, publ. 1999.05.27, IPC6 G01N 29/04.

3. Bobrov V.T., Tarabrin V.F., Ordynets S.A., Kuleshov R.V. Ultrasonic flaw detector "Swallow". RF patent for invention No. 2231783, prior. 2001.08.09., Publ. 2003.07.10, IPC7 G01N 29/04.

4. Sergeev V.A. Device for measuring the thermal resistance of transistors. Application for a patent of the Russian Federation for invention No.2000127414 / 09, prior. 2000.10.31, publ. 2002.10.10, IPC7 G01R 31/26.

5. Medvedev VV, Troitsky O.YU. Device for determining the characteristics of materials. RF patent for invention No. 2212653, prior. 2002.05.28, publ. 2003.09.20, IPC7 G01N 25/18.

6. Abramova E.V., Epiphany A.I., Isakov P.G., Lapovok E.V., Khankov S.I. etc. A device for measuring thermophysical characteristics (options). RF patent No. 54193 for utility model, priority 12/19/2005, publ. 06/10/2006, IPC G01N 25/18 (2006.01).

7. Epiphany A.I., Isakov P.G., Platonov A.S.,. Hankov S.I. Methods for measuring the specific thermal resistance of building envelopes // Building Materials No. 6, 2007, P.45 - 47.

8. Samarsky A.A. Theory of difference schemes. - M .: Nauka, 1977.

Claims (8)

1. A device for measuring resistivity to heat transfer through an object containing a heat exchanger, an inlet pipe, an outlet pipe, a first contact temperature meter, a second contact temperature meter, thermal insulation, the outer surface of the heat exchanger is provided with thermal insulation except for the outer surface of the heat exchanger adjacent to the inner surface of the test object, the exchanger output is connected to the inlet of the outlet pipe, the first contact temperature meter is located between the inner surface of the test object and the outer surface of the heat exchanger, characterized in that it further comprises a heating tank, connecting pipe, storage tank, drain tank, the heating tank is equipped with a heating element and a drain pipe, the connecting pipe is equipped with a valve and a flow meter, the inlet pipe is equipped valve and flow rate meter, the drain pipe is equipped with a valve and flow rate meter, input output pipe is connected to the inlet of the heating tank, the output of the heating tank is connected to the input of the connecting pipe, the output of the connecting pipe is connected to the input of the heat exchanger, the output of the storage tank is connected to the input of the input pipe, the output of the output pipe is connected to the first input of the drain tank, and the output of the drain pipe is connected to the second inlet of the drain tank. 2. The device according to claim 1, characterized in that it further comprises a third contact temperature meter located in the connecting pipe. 3. The device according to claim 1, characterized in that it further comprises a fourth contact temperature meter located in the outlet pipe. 4. The device according to claim 1, characterized in that the second contact temperature meter is located on the outer surface of the test object. 5. The device according to claim 1, characterized in that the second contact temperature meter is located on the side surface of the test object. 6. The device according to claim 1, characterized in that the storage tank is made adjustable in height. 7. The device according to claim 1, characterized in that the storage tank is equipped with an overflow pipe, the output of which is connected to the third inlet of the drain tank. 8. The device according to claim 1, characterized in that it further comprises an external pipeline, the storage tank is equipped with a coolant level meter, the external pipe is equipped with a valve, the control input of which is connected to the output of the coolant level meter.