阅读说明：本技术 气体流量传感器 (Gas flow sensor ) 是由 徐斌 孙运峰 刘清源 李本天 于 2020-04-16 设计创作，主要内容包括：本发明提供一种气体流量传感器,其包括流道以及芯片,所述芯片包括置于流道内的感应区。所述感应区包括加热器、位于加热器一侧的第一热电偶以及位于加热器另一侧的第二热电偶,气体依次流经第一热电偶、加热器以及第二热电偶。所述加热器的长度大于第一热电偶和第二热电偶的长度,且(Y-X)/(A+B)≥0.25,其中Y为加热器的长度,X为热电偶的宽度,A为热电偶的长度,B为加热器与热电偶间的距离。本发明提供的气体流量传感器通过设置加热器与第一热电偶、第二热电偶之间的位置关系使得气体中的污染物不落到感应区,从而可以避免因芯片受污染而影响寿命和精度的问题。(The invention provides a gas flow sensor, which comprises a flow channel and a chip, wherein the chip comprises a sensing area arranged in the flow channel. The induction zone comprises a heater, a first thermocouple positioned on one side of the heater and a second thermocouple positioned on the other side of the heater, and gas flows through the first thermocouple, the heater and the second thermocouple in sequence. The length of the heater is greater than that of the first thermocouple and the second thermocouple, and (Y-X)/(A + B) is greater than or equal to 0.25, wherein Y is the length of the heater, X is the width of the thermocouple, A is the length of the thermocouple, and B is the distance between the heater and the thermocouple. According to the gas flow sensor provided by the invention, the position relation among the heater, the first thermocouple and the second thermocouple is set, so that pollutants in gas do not fall into the sensing area, and the problem that the service life and the precision are influenced due to the pollution of a chip can be avoided.)

1. A gas flow sensor comprises a flow channel (1) and a chip (2), wherein the chip (2) comprises a sensing area (21) arranged in the flow channel (1), the sensing area (21) comprises a heater (211), a first thermocouple (212) positioned on one side of the heater (211) and a second thermocouple (213) positioned on the other side of the heater (211), and gas flows through the first thermocouple (212), the heater (211) and the second thermocouple (213) in sequence, wherein the length of the heater (211) is greater than the lengths of the first thermocouple (212) and the second thermocouple (213), and (Y-X)/(A + B) is greater than or equal to 0.25, wherein Y is the length of the heater (211), X is the width of the thermocouple, A is the length of the thermocouple, and B is the distance between the heater (211) and the thermocouple.

2. The gas flow sensor of claim 1, wherein the ratio of the length of the heater (211) to the length of the thermocouple is 1.5: 1.

3. the gas flow sensor according to claim 1, wherein the heater (211) has a length direction perpendicular to a flow direction of the gas.

4. The gas flow sensor according to claim 1, wherein the flow channel (1) comprises a main flow channel (11) with an inlet end (14), a first sub-flow channel (12) connected to the main flow channel (11), and a second sub-flow channel (13) connected to the main flow channel (11), the sensing area (21) being disposed in the first sub-flow channel (12).

5. The gas flow sensor according to claim 4, wherein the first sub-channel (12), the second sub-channel (13) and the main channel (11) intersect at one point.

6. The gas flow sensor according to claim 5, characterised in that the angle at which the first (12) and second (13) sub-channels intersect in the direction of flow of the gas is obtuse.

7. A gas flow sensor comprises a flow channel (1) and a chip (2), wherein the chip (2) comprises a sensing area (21) arranged in the flow channel (1), the sensing area (21) comprises a heater (211), a first thermocouple (212) arranged on one side of the heater (211) and a second thermocouple (213) arranged on the other side of the heater (211), and gas sequentially flows through the first thermocouple (212), the heater (211) and the second thermocouple (213), and the gas flow sensor is characterized in that the length of the heater (211) is greater than the lengths of the first thermocouple (212) and the second thermocouple (213), and the position relation among the heater (211), the first thermocouple (212) and the second thermocouple (213) meets the requirement that pollutants in the gas do not fall into the sensing area (21).

8. The gas flow sensor of claim 7, wherein the ratio of the length of the heater (211) to the length of the thermocouple is 1.5: 1.

9. the gas flow sensor according to claim 7, wherein the heater (211) has a length direction perpendicular to a flow direction of the gas.

10. The gas flow sensor according to claim 1, wherein the flow channel (1) comprises a main flow channel (11) with an inlet end (14), a first sub-flow channel (12) connected to the main flow channel (11), and a second sub-flow channel (13) connected to the main flow channel (11), the sensing area (21) being disposed in the first sub-flow channel (12).

Technical Field

The present invention relates to a gas flow sensor.

Background

The gas flow sensor comprises a flow channel and a chip. The chip comprises an induction area, and the induction area is arranged in the flow channel. Referring to fig. 1, the sensing region 21 'includes a heater 211', a first thermocouple 212 'disposed at one side of the heater 211', and a second thermocouple 213 'disposed at the other side of the heater 211'. The reference numeral 3 'schematically shows the distribution of the intensity of the thermal field when the heater 211' is heated. As can be seen from the figure, the thermal field is weaker at both ends of the heater 211'. The length of the heater 211' in the prior art is almost equal to that of the thermocouple, so that when the gas containing the contaminants passes over the sensing region, some contaminants fall to both sides of the thermocouple. The measurement of the thermocouples is affected because the contaminants are close to the thermocouples on both sides and are likely to partially fall onto the thermocouples. After long-term operation, measurement result deviations can result.

Disclosure of Invention

The invention aims to provide a method for prolonging the service life and reducing the influence of pollutants on the accuracy of a measurement result after long-term work.

According to one aspect of the present invention, there is provided a gas flow sensor, comprising a flow channel and a chip, wherein the chip comprises a sensing region disposed in the flow channel, the sensing region comprises a heater, a first thermocouple disposed at one side of the heater, and a second thermocouple disposed at the other side of the heater, and gas flows through the first thermocouple, the heater, and the second thermocouple in sequence. The length of the heater is greater than that of the first thermocouple and the second thermocouple, and (Y-X)/(A + B) is greater than or equal to 0.25, wherein Y is the length of the heater, X is the width of the thermocouple, A is the length of the thermocouple, and B is the distance between the heater and the thermocouple.

Preferably, the length ratio of the heater to the thermocouple is 1.5: 1.

preferably, the length direction of the heater is perpendicular to the flow direction of the gas.

Preferably, the flow channel comprises a main flow channel with an air inlet end, a first branch flow channel connected with the main flow channel and a second branch flow channel connected with the main flow channel, and the sensing area is arranged in the first branch flow channel.

Preferably, the first branch flow channel, the second branch flow channel and the main flow channel intersect at one point.

Preferably, the included angle of the intersection of the first subchannel and the second subchannel along the flow direction of the gas is an obtuse angle.

According to one aspect of the present invention, a gas flow sensor is provided that includes a flow channel and a chip including a sensing region disposed within the flow channel, the sensing region including a heater, a first thermocouple on one side of the heater, and a second thermocouple on the other side of the heater. The gas flows through the first thermocouple, the heater and the second thermocouple in sequence. The length of the heater is greater than that of the first thermocouple and the second thermocouple, and the position relationship among the heater, the first thermocouple and the second thermocouple meets the condition that pollutants in the gas do not fall into the induction area.

Preferably, the length ratio of the heater to the thermocouple is 1.5: 1.

preferably, the length direction of the heater is perpendicular to the flow direction of the gas.

Preferably, the flow channel comprises a main flow channel with an air inlet end, a first branch flow channel connected with the main flow channel and a second branch flow channel connected with the main flow channel, and the sensing area is arranged in the first branch flow channel.

According to the gas flow sensor provided by the invention, the position relation among the heater, the first thermocouple and the second thermocouple is set, so that pollutants in gas do not fall into the sensing area, and the problem that the service life and the precision are influenced due to the pollution of a chip can be avoided.

Drawings

Fig. 1 is a schematic diagram of a sensing region of a chip in the prior art.

Fig. 2 is a schematic view of a gas flow sensor according to the present invention.

FIG. 3 is a schematic diagram of a sensing region of a chip according to the present invention.

Detailed Description

Referring to fig. 2 to 3, the present invention provides a gas flow sensor 100, which includes a flow channel 1 and a chip 2. The chip 2 comprises a sensing region 21 disposed within the flow channel 1. The flow channel 1 comprises a main flow channel 11 with an inlet end 14, a first sub-flow channel 12 connected to the main flow channel 11 and a second sub-flow channel 13 connected to the main flow channel 11. The sensing region 21 is disposed in the first shunt passage 12. The first branch flow channel 12, the second branch flow channel 13 and the main flow channel 11 intersect at one point. The included angle of the intersection of the first subchannel 12 and the second subchannel 13 along the flow direction of the gas is an obtuse angle. The gas flows almost linearly from the main flow channel 11 to the second branch flow channel 13. The first branch flow channel 12 extends smoothly from the main flow channel obliquely backward and upward, then extends horizontally, and finally extends almost vertically, and finally merges with the second branch flow channel 13 at the outlet. The sensing region 21 is disposed in a horizontally extending portion of the first shunt passage 12. Reference numeral 3 indicates the distribution of the intensity of the thermal field of the heater 211. The two ends of the heater 211, which are longitudinally extended (i.e., in the length direction), enable the heater to generate a thermal field in a larger area, thereby increasing the transpiration effect above the two sides of the heater, and enabling the pollutants to be far away from the thermocouple effective induction area, thereby avoiding affecting the measurement result and increasing the service life of the sensor due to pollution.

The sensing zone 21 includes a heater 211, a first thermocouple 212 located at one side of the heater 211, and a second thermocouple 213 located at the other side of the heater 211. The gas flows through the first thermocouple 212, the heater 211, and the second thermocouple 213 in sequence. The length of the heater 211 is greater than the lengths of the first thermocouple 212 and the second thermocouple 213, and (Y-X)/(A + B) is greater than or equal to 0.25, wherein Y is the length of the heater 211, X is the width of the thermocouple, A is the length of the thermocouple, and B is the distance between the heater 211 and the thermocouple. Since the first thermocouple 212 and the second thermocouple have the same length and width and are symmetrically arranged with respect to the heater, the length of the thermocouple is the length of the first thermocouple 212 and the second thermocouple, and the width of the thermocouple is the width of the first thermocouple 212 and the second thermocouple.

Preferably, the ratio of the length of the heater 211 to the length of the thermocouple is 1.5: 1.

the length direction of the heater 211 is perpendicular to the flow direction of the gas. Since the sensing area 21 is disposed at the horizontal extension of the first subchannel 12, the gas flows in the horizontal direction when the gas flows into the area. The sensing region 21 is disposed in a vertical direction in the drawing, so that the length directions of the heater 211, the first thermocouple 212 and the second thermocouple 213 are perpendicular to the gas flow direction therein.

When the positional relationship between the heater 211 and the first and second thermocouples 212 and 213 is changed by those skilled in the art, the contaminants in the gas will not fall to the sensing region 21 when the relationship is satisfied. The lifetime and measurement accuracy of the chip can be increased by allowing the contaminant portion of the gas to fall into the sensing region 21.

It will be apparent to those skilled in the art that various modifications and variations can be made to the above-described exemplary embodiments of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.