Self-heating heat responsive element and liquid level detector assembled thereby

A technology of liquid level detector and thermal element, applied in the direction of liquid level indicator for physical variable measurement, etc., can solve the problems of small working current, short response time, slow response, etc., and achieve small external interference and strong anti-interference. Ability, stable performance

Inactive Publication Date: 2009-10-14
瞿瑛
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The small thermistor has a small working current and cannot self-heat, and can only passively accept ambient heat. When the liquid temperature is close to the air temperature, the temperature difference cannot be detected, and the liquid level detection function cannot be realized
[0007] The power type thermistor, through a large current, can self-heat. When the temperature of the liquid and the air are close, the temperature of the thermistor in the air is higher because the heat in the air is not easy to dissipate. Low, can realize the above detection function, but the problems are: this kind of thermistor has large volume, large power consumption, and slow response
Since there is no heat conduction medium that dissipates heat outward, and the existence of the packaged glass tube, it cannot perform good heat exchange with the outside world and cannot be used for liquid level detection
[0009] According to the existing technology, a thermal sensor dedicated to liquid level detection has not yet been proposed. It should achieve: miniaturization, short response time, controllable heat generation, and simple application circuit

Method used

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  • Self-heating heat responsive element and liquid level detector assembled thereby
  • Self-heating heat responsive element and liquid level detector assembled thereby
  • Self-heating heat responsive element and liquid level detector assembled thereby

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Such as figure 1 Shown: a self-heating thermosensitive element, the key of which is: composed of a heating resistor 1, a heat conducting medium 2, and a thermosensitive element 3, the heat conducting medium 2 is connected to the heating resistor 1 and the thermosensitive element 3, and the heat conducting medium 2 is connected with The heating resistor 1 is in close contact with the heat-sensitive element 3, and the heat-conducting medium 2 is exposed to the working environment. The heat conduction medium 2 is in close contact with the working environment medium, which can realize sufficient heat exchange.

[0051] The heat conducting medium 2 is located between the heating resistor 1 and the heat sensitive element 3 .

[0052] Its working principle is: when the self-heating thermal element is in the air, the heat emitted by the heating resistor 1 is transferred through the heat-conducting medium 2, a small part is dissipated into the air, and most of it reaches the th...

Embodiment 5

[0063] Such as Figure 5 Shown: in order to fully express the application of self-heating thermal element, the present invention describes a kind of liquid level detector, and its key is: by reference self-heating thermal element K, output circuit, a group of self-heating thermal element 61 ~6i, a set of voltage comparators 71~7i and a set of voltage resistors;

[0064] Wherein the heating resistor 1 in the first self-heating thermistor 61 is connected between the positive and negative poles of the power supply, and the thermistor 3 in the first self-heating thermistor 61 is connected in series with the first voltage dividing resistor R11 and then connected to the positive and negative poles of the power supply. Between the negative poles, the common terminal of the thermistor 3 and the first voltage dividing resistor R11 is connected to the positive or negative input terminal of the first voltage comparator 71;

[0065] The connection relationship between the self-heating th...

Embodiment 6

[0072] Embodiment 6, the working principle of this embodiment is the same as that of Embodiment 5, the difference is that:

[0073] Such as Figure 6 As shown: the output terminals of the voltage comparators 71-7i group are connected with a V / I conversion circuit, and the V / I conversion circuit is composed of a V / I converter 10, a pull-down resistor R3 and a group of series resistors R31-R3 (i-1) composition;

[0074] Wherein the first series resistor R31 is connected between the output terminals of the first voltage comparator 71 and the second voltage comparator 72, and the second series resistor R32 is connected between the second voltage comparator 72 and the third voltage comparator Between the output terminals of 73;

[0075] The other series resistors R33~R3 (i-2) The connection relationship with other voltage comparators 73~7i groups is consistent with the connection relationship of the first and second series resistors R31, R32, the first, second and third voltage ...

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Abstract

The invention discloses a self-heating heat responsive element and a liquid level detector assembled thereby. The self-heating heat responsive element comprises a heating resistor, a heat-conducting medium and a heat responsive element, wherein the heat-conducting medium is respectively and tightly contacted with the heating resistor and the heat responsive element. The heat responsive element can be a heat responsive resistor, a diode and a triode. The liquid level detector comprises the self-heating heat responsive element and a voltage comparator, wherein the self-heating heat responsive element is a special element for detecting liquid level and can reliably work in a wider temperature range. A liquid level detection circuit is simple, flexible and strong in disturbance resisting capability and can exactly detect the liquid level.

Description

technical field [0001] The invention relates to a self-heating thermosensitive element and a liquid level detector assembled from the self-heating thermosensitive element. Background technique [0002] The detection of the liquid level by assembling the liquid level detector with thermal elements has the advantages of low cost and no mechanical wear, so it is widely used. It mainly arranges a row of heat-sensitive elements according to the height of the liquid level. It uses the characteristics that the dissipation constant of heat-sensitive elements in liquid is different from that in air or steam. When the heat-sensitive elements are immersed in liquid, the liquid acts as The heat dissipation medium, at this time, heats the heat sensitive element, the dissipation constant of the heat sensitive element is large, and the temperature rises slowly; when the heat sensitive element is in the air, it loses the good heat dissipation medium of liquid, and the temperature of the hea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01F23/24
Inventor 瞿瑛
Owner 瞿瑛
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