The flexible heating element

 

(57) Abstract:

The invention relates to electrothermal and can be used in the manufacture of polymer heaters for domestic and industrial use. In a flexible heating element in the base conductive fabric is made of solid insulating filaments, placed between the electrodes, and the weft is made of integrated electrically conductive heat-generating filaments, placed perpendicular to the electrodes. Mathematical ratios, ensuring the establishment of electrical safety resistive layer, in accordance with which calculated the number of conductive filaments (n) per unit length of the resistive layer, the number of electrodes (K) and the number of their constituent metallic yarn (m). As an integrated conductive heat-generating filament used multicomponent filament structure "sheath-core" containing "shell" fluorinated polyolefin-based kienpointner copolymer of tetrafluoroethylene with vinylidenefluoride, and in the core of polycaproamide or glass fiber. The technical result that can be obtained from the use of the invention is to increase electrometers the tx2">

The invention relates to electrothermal, namely, flexible heating elements, the resistive layer which is executed in the form of woven fabrics comprehensive elektroprovoda threads, and can be used in everyday life, medicine, celosamente and devices for heating liquids and gases used in various industries.

Known woven heater, in which the warp and the weft is made of electrically conductive and electroconductive yarns laid by rotation in one direction of the fabric, and the electrodes are located along the base (U.S. patent N 3349359, CL H 05 B 3/34, 1967)

Also known woven heater, electroconductive filaments which are made of a complex of cotton fibers, with a volumetric ratio of electroconductive yarns to the conductive warp threads is 1:1 to 1: 1.5, and the volumetric ratio of the electrically conductive warp and weft threads is 1:1.5 to 1:10 (RF patent N 2046552, CL H 05 B 3/36, 1995)

In the above invention solves the problem of reducing the shrinkage of the resistive layer in the manufacturing process and operation of the heating elements.

A similar problem is solved in a flexible heating element (patent USSR N 1794284 A3, class H 05 B 3/38, 1993 the UNC conductive threads, insulating yarns and metallized yarns, incorporated in the electrodes, which are placed along the edges of the resistive element and bypass the integrated conductive polymer strands.

The main disadvantage of the heating elements is that they do not regulate the ratio between the required technical characteristics of the heating element and is required for practical implementation of textile structure of the resistive layer. This could result in reduced reliability and durability of the flexible heating element.

The closest analogue, selected as a prototype, is the invention according to the patent of the USSR N 1794284.

The primary development task is to create a flexible heating element, which would be the above mentioned disadvantages, and the textile structure of the resistive layer in the form of conductive tissues regulate the required technical parameters of the heating element for the different operating conditions of the products based on it.

The technical result that can be obtained from the use of the invention is to improve electrical safety and the Shen and the technical result is achieved due to the fact, in flexible heating element containing the resistive layer in the form of a conductive fabric, the weft and the base of which is made of integrated electrically conductive polymer fuel yarn, the insulating yarn and electrodes, made in the form of metallic threads, eg integrated electrically conductive heat-generating polymer filament according to the invention, the base conductive fabric is made of solid insulating filaments, placed between the electrodes, and the weft is made of integrated electrically conductive heat-generating polymer filaments, placed perpendicular to the electrodes, while n is the number of conductive filaments per unit length of the resistive layer and K*the number of electrodes per unit width of the resistive layer should correspond to the ratios

< / BR>
< / BR>
where P is the rated power of the heating element, W;

e- maximum permissible dissipation per unit length of conductive thread, W/m;

A - the length of the resistive layer, m;

B - the width of the resistive layer, m;

U - specified supply voltage, V;

Rn- linear electrical resistance of the conductive filament, Ohm/m,

and the number IU testout ratios

< / BR>
< / BR>
where P is the rated power of the heating element, W;

K*the number of electrodes per unit width of the resistive layer, PCs;

U - specified supply voltage, V;

m- limit the dissipation per unit length metallic threads, W/m;

Rmspecific electrical resistance of metallized yarn, Ohm/m;

this complex conductive polymer fuel thread has the structure of a "sheath-core" and contains the "core" of polycaproamide or glass fibers, as in "shell" shaunaolney fluorinated polyolefin-based copolymer of tetrafluoroethylene with vinylidenefluoride in the following ratio of ingredients, wt.%:

(a) for "kernel" of polycaproamide fibres:

polycaproamide fiber - 62 - 56

a copolymer of tetrafluoroethylene with vinylidenefluoride - 23 - 25

furnace soot - 15 - 19

b) for the "core" of glass fiber:

glass fiber - 69 - 54

a copolymer of tetrafluoroethylene with vinylidenefluoride - 19 - 20

furnace soot - 12 - 16

Distinctive features are essential, because each of them separately and together is aimed at solving the problem and achieving a new technical RWA is its electric power. To ensure the specified value of the specified parameter resistive layer flexible heating element must contain an integrated electrically conductive fuel strands oriented perpendicular to the electrodes, i.e., placed on a duck conductive fabric, and their number should not be less than the value defined by the ratio n P/eAB (I). With fewer conductive heat-generating threads in the resistive layer will lead to overheating and destruction and, as a consequence, the output of the heating layer of the system. A similar result will occur if part of the electrically conductive threads will be placed on the basis of conductive fabric, i.e., oriented parallel to the electrodes. This circumstance is explained by the fact that at the breakage of the conductive strands disposed between the electrodes on a duck conductive fabric, there will be a redistribution of the electric current between neighboring conductive threads, i.e., conductive thread, located perpendicular to the electrodes, electric current in the break place is redistributed to the neighboring conductive thread, will overload their duck with education for some time new the all new electro-conductive yarn, until the failure of the entire heating element.

Distribution supplied to the heating element power supply between the conductive heat-generating threads through electrodes metallized threads. The number of such electrodes in the resistive layer, depending on specified electrical and geometrical parameters of the heating element must match the expression With fewer electrodes electric power consumption will be less than a specified value and, as a consequence, the surface temperature of the heating element will be lower than desired. With a large number of electrodes, the power consumption will be greater than the specified value, which will inevitably lead to overheating of the conductive threads and, as a consequence, the output of the heating element failed.

The amount of metallic threads in the electrode should match the expressions

With fewer metallic threads (when passing through the electric current will overheat and destroy the conductive thread, envelopes them, that will lead to the exit of the heating element failed.

Use the glass fiber, but the shell is a copolymer of tetrafluoroethylene with vinylidenechloride filled furnace soot, will improve the manufacturability and quality of the heating element in the process of its manufacture and operation.

These distinctive essential features are new, because their use in the prior art, analogs and prototype not found, which allows to characterize the proposed technical solution according to the criterion of "novelty".

One set of new essential features with commonly known essential features that allow one to solve the problem and achieve new technical result, which allows to characterize a new technical solution significant differences compared with the prior art, analogs and prototype. A new technical solution is the result of research and development testing and creative contribution, obtained without the use of standard design solutions or any of the recommendations in its originality and content performance meets the criterion of "inventive step".

In Fig. 1 presents a fragment of the conductive who maintain (b) the number of electrodes in a variant implementation; in Fig. 3 presents the structure of a complex conductive heat-generating threads containing "core" of the polycaproamide or glass fibers, as in "shell" shaunaolney tetrafluoroethylene polymer with vinylidenefluoride.

Fragment of conductive fabric for resistive element contains an array of insulating filaments 1, is placed between the electrodes 2, and the integrated electrically conductive heat-generating filament 3, oriented perpendicular to the electrodes. The number of integrated electrically conductive heat-generating threads is determined based on the set of technical parameters of the heating element and the structural parameters of the conductive fabric.

Technical parameters of the heating element is power (P, W), voltage (U, B) and the dimensions of the resistive layer length (A, m) and width (B, m). Based on the above mentioned parameters, it is necessary to determine the structural parameters of the resistive layer, namely, the number of integrated electrically conductive fuel yarns per unit length of the resistive layer (n/A, PCs/m); number of electrodes (K*, pieces) and the number of metallic threads in the electrode (m, PC). The calculations of these parameters, not only aetsa factore(W/m). Hence the total dissipation of the n-th number of threads corresponding to power the heating element, determined by the relation

P neAB or neAB P,

here

< / BR>
II. Calculation of system power distribution. In Fig. 2 shows a variant of execution of the resistive layer with a different number of electrodes, connected among themselves by means of tokovodov 4. As can be seen from the sketches resistive layer, shown in Fig. 2, A and B are respectively the length and width of the resistive layer, L is the distance between the electrodes, and the number of electrodes is equal to K*= K + 1, where K is the number of bands from an array of insulating threads. Based on this

K = B/L or L = B/K

Calculate the power distribution in the heating element is determined from the fact that a certain number of integrated electrically conductive filaments per unit length of the resistive layer (n); the dimensions of the resistive layer A and B (length and width respectively) (m); linear electrical resistance of the integrated conductive thread (Rn, Ohm/m).

Defined electrical resistance of the fragment of the resistive layer (R1located between adjacent electrode is about L = B/K, get R = 1/KRnB/AnK;

we know P = U2/R, then R = U2/P

or K2= PBRn/U2'an, where

In accordance with the above, the number of electrodes in the resistive layer, depending on specified electrical and geometrical parameters of the heating element is determined by the ratio

< / BR>
III. The determination of the number of metallic threads in the electrode. The determination of the number of metallic threads in the electrode produced considering the fact that the current flowing from the power source to the electrodes, should not lead to the destruction of the metallic filaments constituting the electrodes. The total current in the resistive layer, equal

I = P/U,

where P is the power of the heating element, W;

U - specified supply voltage, Century

This current is distributed between the electrodes. If electrodes K, then for each of them carrying current:

(a) for an even number of electrodes

Ik= 21/K*= 2P/K*U,

b) for an odd number of electrodes

Ik= 21/K*-1 = 2P/(K*-1)u

The current flowing through the electrodes, in turn, is allocated between the components of its metal threads. If these threads, m, b) for an odd number of electrodes

I1= 2P/(K*-1)Um.

When the current passing through the metallic thread should not destroy it, i.e., the dissipation caused by the passage of current, shall not exceed the maximum heat dissipation for a given type metallic yarn. If we denote the limiting dissipation per unit length metallic thread size m (W/m), then by Ohm's law

I2iRmm,

where Rm- electrical resistivity metallic threads, Ohm/m

Then the number of metallic yarn (m) in the electrode will be:

(a) for an even number of electrodes

or

b) for an odd number of electrodes

or

Not less important task was the development of an integrated electrically conductive heat-generating threads resistive layer that would provide performance flexible heating element.

The structure of an integrated electrically conductive heat-generating threads, shown in Fig. 3, consists of a "core" on the basis of polycaproamide 5 glass 6 fibers around which a localized conductive composition 7 of kienpointner copolymer of tetrafluoroethylene with vinylidene the priority themes the specified copolymer of the known fluorinated polyolefins in combination with a furnace soot has the lowest electrical resistivity. This is due to the fact that highly structured furnace carbon black is hydrophobic and is well combined with the fluorinated polyolefins. In addition, on the surface of the particle furnace black almost no oxygen-containing complexes, which is important for obtaining a composition with a high proportion of use of the conductive material.

However, the threads of the composition of the copolymer+carbon black may be subjected to significant plastification cooker hoods up to 500%. This circumstance demanded the introduction of the structure of the filament reinforcing element is "kernel". The basic requirements for reinforcing element multifilament yarn were as follows: high mechanical strength and chemical-resistant. From the above, from all types of fibers are most appropriate polycaproamide, but to create heating elements running within 130-180oC, should be used as "core" complex threads of glass fibers.

The technology of manufacturing integrated conductive polymer threads on su the different examples.

Example 1. From the measuring device in the apparatus of disolver enters solvent is acetone and the copolymer. Through pipe load a specified amount of soot and prepare a spinning solution. Next, produce a dispersion of soot particles in a rotary pulsational mixer and after the evacuation serves the resulting solution in spunbond kit which simultaneously served and fibrous filler. Filler ends with the opening of 0.9 - 1.1 mm, which governs the thickness of the applied layer. On exit from the die fibrous filler is fed into the mine, where a counter that serves hot air, heated to a temperature of 120 - 135oC. While the acetone is removed from the mine on regeneration and integrated conductive thread is made on the package for further processing in tissue filler with specified technical and textile characteristics. In the process of manufacturing integrated conductive yarn as in example 1, the ingredients were taken in the following ratio, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 24

furnace soot - 10

polycaproamide fiber - 66

Example 2. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt is on - 64

Example 3. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 23

furnace soot - 15

polycaproamide fiber - 62

Example 4. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 25

furnace soot - 19

polycaproamide fiber - 56

Example 5. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 26

furnace soot - 22

polycaproamide fiber - 52

Example 6. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 16

furnace soot - 09

glass fiber - 75

Example 7. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 17

furnace soot - 10

glass fiber - 73

Example 8. Carried out analogously to example 1 in the following ratio ing the - 12

glass fiber - 69

Example 9. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 20

furnace soot - 16

glass fiber - 64

Example 10. Carried out analogously to example 1 in the following ratio of ingredients multifilament yarn, wt.%:

a copolymer of tetrafluoroethylene with vinylidenefluoride - 22

furnace soot - 18

glass fiber - 60

The results of tests on the mechanical and electrical characteristics of integrated electrically conductive yarns in examples 1-10 are presented in the table.

Analysis of the data presented in the table shows that the most suitable are complex electro-conductive yarn according to examples 3, 4 ("core" is made of fibers of polycaproamide) and 8, 9 ("core" is made of glass fibers), as the threads of these compositions have the smallest linear electrical resistance (1400-1500 Ohm/m for thread-based nylon and 1250-1300 Ohm/m for thread-based glass) and have a minimum elongation at break. In addition, these threads have a high quality shell is not damaged in the process made filament yarn patterns "sheath-core", containing "shell" shaunaolney copolymer of tetrafluoroethylene with vinylidenefluoride, and in the core filler on the basis of polycaproamide (option I) or glass fiber (option II) is presented below.

An example calculation of the structure of the resistive layer (variant I).

Set: rated power of the heating element P = 2000 W; supply voltage U = 220; length A = 5 m, width B = 1 m

You want to determine the structure of the resistive layer, providing specified technical parameters.

Solution. As the heat-generating integrated conductive thread choose thread according to example 3 (see table.), linear electrical resistance which Rn= 150,000 Ohms/m with maximum permissible heat dissipation per unit length of the threade= 0.5 W/m With an expression I determined the number of complex threads per unit length of the resistive layer:

or

n = 2000/0,551 = 800 threads/meter.

Using the expression II will perform the calculation to determine the required number of electrodes in the resistive layer:

or

< / BR>
Round the resulting expression to integers (excluding fractional part) and by reusing expressions II we define the number Teplov the 20001500001/484005(2-1)2= 1239 strands/meter.

Thus, the desired resistive layer should contain n = 1239 filament yarn per unit length of the resistive layer and the two electrodes of metallic threads located on the edges of the resistive layer and the envelopes integrated conductive thread.

Using expressions III we define the number of metallized threads in the electrode taking into account the fact that the used floss brand MC copper-based with specific electrical resistance Rm= 1 Ohm/m and maximum heat dissipation per unit lengthm= 0.5 W/m

or

.

Thus, to ensure the reliability of the heating element by providing the specified parameters resistive layer should contain 1239 threads per 1 m of its length, which is placed between the two electrodes 13 metallized yarn type MC each.

An example calculation of the resistive layer (variant II).

Set: rated power of the heating element P = 3000 watts; supply voltage U = 36 In; sleeve length A = 1 m, width B = 1 m

Solution. Select the type and quantity of fuel strands. Suppose that we (as in the example according to the variant I) use complex thread, containing in the core policypro is but a valid dissipatione= 0.5 W/m With a linear density is 55 Tex and textile provides maximum density 2000 strands/meter length of the conductive fabric.

To ensure the health of the heating element, the amount of fuel threads per 1 m length of the resistive layer according to the expression I should be

< / BR>
The resulting value is above the maximum realizable value at textile weaving density (2000 strands/meter) integrated heat-generating thread with the "core" of polycaproamide fibres. Therefore, it is necessary to use a composite conductive filament with a large maximum allowable heat dissipation.

The table shows that the most suitable is a complex conductive thread with the "core" of the glass fibers, linear electrical resistance which Rn= 120000 Ohm/m with the maximum permissible heat dissipatione= 1,5 W/m (table, example 9). When the linear density is 100 Tex and textile provides maximum density 1600 strands/meter length of the conductive fabric.

According to the expression I in this case, the amount of conductive heat-generating threads on a 1 m length of the resistive layer sostavilo element, the corresponding specified characteristics.

Using the expression II, conduct a preliminary assessment of the required number of electrodes in the resistive layer:

or

< / BR>
Rounding the resulting value to integers (excluding fractional part) and by reusing expressions II check the amount of fuel of threads per unit length of the resistive layer:

n = RnPB/U2A(K*-1)2or

n = 12000030002/3621(24-1)2= 1050 strands/meter.

Thus, the resistive layer with dimensions S = A B = 1 m 2 m = 2 m must contain 1050 integrated electrically conductive threads with the "core" of the glass fibers and the electrode 24 of metallized yarns, spaced equally across the width of the resistive layer.

Using expressions III-defined number of metallic threads in each electrode, which used metallic copper thread brand MC with specific electrical resistance Rm= 1 Ω/m and the maximum dissipationm= 0.5 W/m

or

.

Thus, to ensure the health and reliability of the heating element by providing the specified parameters resistive layer should be avannah threads brand MC each, posted by evenly across the width B of the resistive layer (2 on the sides and 22 between them).

The test developed flexible heating element based on the calculated in accordance with the ratios I-IV resistive layer created on the basis of a comprehensive fuel conductive yarn type "sheath-core" from kienpointner copolymer and fibrous fillers, showed high reliability and efficiency in operation of various products.

Thus, the proposed new technical solution in the specified essential features meets the criterion of "industrial applicability", i.e. the level of the invention.

1. The flexible heating element containing the resistive layer in the form of a conductive fabric, the weft and the base of which is made of integrated electrically conductive polymer fuel yarn, the insulating yarn and electrodes, made in the form of metallic threads, eg integrated electrically conductive heat-generating polymer filament, characterized in that the base of the conductive fabric is made of solid insulating filaments, placed between the electrodes, and the weft is made of complex elektroproektmontazh threads per unit length of the resistive layer and the K* - the number of electrodes per unit width of the resistive layer must conform to the following ratios:

< / BR>
< / BR>
where P is the rated power of the heating element, W;

e- maximum permissible dissipation per unit length of conductive thread, W/m;

A and B are respectively the length and width of the resistive layer, m;

U - specified supply voltage, V;

Rn- linear electrical resistance of the conductive filament, Ohm/m

2. The flexible heating element under item 1, characterized in that the amount of metallic threads in the electrode for even m1and odd m2the number of electrodes must comply with the following ratios:

< / BR>
< / BR>
where P is the rated power of the heating element, W;

K* is the number of electrodes per unit width of the resistive layer pieces;

U - specified supply voltage, V;

m- limit the dissipation per unit length metallic threads, W/m;

Rmspecific electrical resistance of metallized yarn, Ohm/m

3. The flexible heating element according to any one of paragraphs.1 and 2, characterized in that the integrated conductive fuel thread has the structure "Obolo the Institute on the basis of a copolymer of tetrafluoroethylene with vinylidenefluoride in the following ratio of ingredients, wt.%:

Polycaproamide fiber - 62 - 56

A copolymer of tetrafluoroethylene with vinylidenefluoride - 23 - 25

Furnace soot - 15 - 19

4. The flexible heating element according to any one of paragraphs.1 and 2, characterized in that the integrated conductive fuel thread has the structure of a "sheath-core" and "core" integrated conductive heat-generating filament contains glass fibers in the following ratio of ingredients, wt.%:

Glass fiber - 69 - 64

A copolymer of tetrafluoroethylene with vinylidenefluoride - 19 - 20

Furnace soot - 12 - 16

 

Same patents:

Flexible heater // 2098927
The invention relates to the field of electric heating, namely, to designs of flexible resistive heater surface type used for space heating

Heater // 2116706
The invention relates to the field of electrothermics, namely to electric heaters

The invention relates to the field survey and can be used in flexible heaters made from polymer materials used for space heating

The invention relates to the field of special requests and can be used in devices for heating, in particular in the sill heaters or dryers

Flexible heater // 2094958
The invention relates to the field of special requests and can be used in electric heating elements

Film heater // 2088047
The invention relates to flat heaters of the radiant type, in particular for film heaters used for heating of domestic and industrial premises

The invention relates to underwater technology, namely the associated equipment diving equipment, and can be used when conducting diving operations

The invention relates to multilayer materials with electric and can be used for the manufacture of clothing

The invention relates to the electrical industry and can be used in the manufacture of flexible polymer heaters for clothes for special purposes, for heating pipes, appliances, etc

The invention relates to electrical engineering, in particular to a cable technology

The invention relates to the field of electrical engineering

Flexible heater // 2110901
The invention relates to the design of electric heaters and can be used for local heating in the technical and domestic purposes, in particular seats of cars and overalls operators forestry machines while working outdoors in the winter season

Flexible heater // 2106765
The invention relates to teplojelektrotekhnika, in particular, to flexible heaters, and can be used to create heating systems, for example, residential and industrial buildings

The invention relates to materials having the ability to conduct an electric current

The invention relates to electrical engineering, in particular to a flat electric heating elements

Flexible heater // 2079979
The invention relates to the field of electrical engineering, in particular, to flexible heaters in the form of a tape that can be used in various sectors of the economy (construction, agriculture, household and other)

The invention relates to electrical engineering and can be used for the manufacture of polymer heating elements

Flexible heater // 2076462
The invention relates to electrical engineering and is intended for local heating of individual objects or areas of the body
Up!