JPS60218032A - Thermal flow rate sensor - Google Patents

Abstract

PURPOSE:To maintain a proper insertion state, to hold specific tensile strength, and to improve reliability by providing a collar which serves as a stopper at a position which is specific length away from one end of the insulating tube insertion side of the lead member of the thermal flow rate sensor. CONSTITUTION:The flow rate sensor consisting of a temperature-sensitive resistor 2 and a lead 30 is connected to a base conductor 11 by spot welding, an orifice 10 is provided at the upstream side of the temperature sensing resistor 2, and a flow of fluid 12 accelerated by the orifice 10 strikes the temperature sensing resistor 2; and the collar 6 is provided to one end of the lead part 30, which is inserted and fixed where one end surface of an insulating tube 1 abuts on the collar 6, so the contacting area between the insulating tube 1 and lead 30 increases. Consequently, the tensile strength is increased and a falling defect of the lead is reduced, and the insertion length of the lead part 30 becomes constant, so that variance in thermal capacity of the sensor is reduced.

Description

[Detailed Description of the Invention] [Technology of the Invention: Minute Hand] Is the temperature dependence of the temperature-sensitive resistance of the present invention? The present invention relates to a heat-sensitive flow sensor that detects the flow rate or rt flow rate of a fluid.

[Prior art]

Conventionally, there has been a type of flow rate sensor for this type of yuzu, as shown in FIG. In the figure, (1) is a cylindrical insulating tube made of a gas insulator such as ceramic, and on the outer surface of the insulating tube there is a material such as platinum 17'C or nickel that has a certain electrical resistance.
A temperature-sensitive resistor (2) is formed that changes depending on the temperature. Then, rod-shaped rods (8) made of a conductive material are inserted into the openings at both ends of the insulating tube (1). ing. Further, the surface of the temperature-sensitive resistor (2) is covered with a glass material or the like to form a resistor 111 M (5).

The heat-sensitive type flow sensor configured as described above is arranged in the flow path, and the flow is applied to the temperature-sensitive resistor (2) through the lead (8) and the conductive paste (through which the paper passes). Temperature resistance (2)
The flow rate or flow velocity can be detected by changing the temperature of the tube to keep it constant and measuring the change in current.

However, in the flow sensor of this configuration, there are two frames and an upper IC.
j The heat generated by the temperature-sensitive resistor (2) is transmitted to something other than the fluid, that is, to the outside via the lead (8).
- It is necessary to make the lead (8) as small as possible.
Therefore, it is necessary to use stainless steel, etc., which has a low thermal conductivity, and to select the shape and dimensions so that the outer diameter is small within the allowable range of mechanical strength. Reducing the diameter will lead to misalignment of the insulating tube (1) from the central axis, defective formation of the conductive paste, and a significant decrease in the tensile strength of the lead (8).

In addition, during the process of inserting the lead (8) into the openings at both ends of the insulating tube (1), the accuracy of the insertion length cannot be obtained because the lead (8) does not have a stopper.
1) Insert the two leads (7'C) from the openings at both ends of the circular part (
8) was sometimes short-circuited to -contract.

Since it is configured more like the conventional heat-sensitive algae sensor rX, the lead (8) and insulating tube (1) O fixation is unstable.
There were disadvantages such as short circuit or cut-off condition.

[Summary of the invention]

゛ The present invention was made in order to eliminate the drawbacks of the conventional products as described above, and includes a flange that serves as a stopper when inserting the lead into the openings at both ends of the insulating tube. The purpose of the present invention is to provide a highly reliable heat-sensitive flow center that maintains a proper insertion state and maintains a predetermined tensile strength by providing the lead.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained using the t-first case.

In FIG. 1, (1) is an insulating tube made of ceramic η islands, and the shape of the tube is, for example, an outer diameter of III, an inner diameter of 0.6 fins, and a length of 3.20 mm. A platinum layer serving as a temperature-sensitive resistor (2) is vaporized on the outer surface of the insulating tube (1). t
It forms an ao+rt flange (6) or indicates one lead, and the outer diameter is 0.
A circular collar (6) of 71W to 1 seaweed is molded into 19 pieces by punching or the like.

The outer diameter of the insertion part (7) of this lead is 0.5 silk, the outer diameter of the support part is U0,311+, and the support S is formed slightly thinner than the insertion part fc.

After applying silver paste, etc. on the outer surface of the insertion part of the flanged lead 1alJI and on the inside of the insulating tube (1), open both ends of the insulating tube (1). Insert a pair of leads from S, add 1tL1 of sintering,
Thereafter, a heat resistor made of an electrical insulator such as glass is formed on the outer surface of the temperature-sensitive resistor (2).

The second factor shows an installation example of a heat-sensitive flow sensor manufactured by the above-mentioned manufacturer. As shown in the figure, a flow sensor σ consisting of a temperature-sensitive resistor (2) and a support conductor made of stainless steel (1!9) is connected to the spot l111 contact, and the #temperature-sensitive resistor (2) is An orifice 4 is installed in the upper fit@, and the structure is such that the flow of fluid accelerated by the orifice impinges on the temperature-sensitive resistor (2).At this time, the flow direction is On the other hand, connect the support conductor (b) to the flow tube (
9).

By inserting and holding the collar (6) in this manner until it comes into contact with one end surface of the insulating tube (1), the following effects can be obtained.

(1) Since the contact area between the insulating tube (1) and the lead (2) increases, the tensile strength increases and the number of lead removal defects is reduced.

By keeping the insertion length of (phantom lead (2)) constant,
The variation in heat capacity of the sensor is reduced.

(81g Temperature resistor (g) rxf v -t aa + to A
II Pipe (i) o Since the central axes match and maintain a proper posture, the heat radiation coefficient becomes stable and power adjustment becomes easy.

(4) By making the insulating tube (1) constant between the insertion part of the lead and the collar (6), it is possible to reduce the outer diameter of the support part of the lead. This reduces heat loss. 1
．． 4 ICs and FCs for highly accurate flow measurement.

In addition, in the above example, platinum black M was used as the rt temperature sensitive resistor (2).
J film, dispersed in an organic vehicle on platinum powder.
The same effect can be obtained by applying a thin film of nickel, copper, etc.
In addition, lead +301 is made of stainless steel, 7 is made of platinum,
A similar effect can be achieved by adding nickel.

〔Effect of the invention〕

As described above, according to the present invention, the lead member Kj? By providing a flange serving as a stopper at a predetermined length from one end of the insulating tube insertion device, a proper connection state can be obtained and reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view of a heat-sensitive flow sensor according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of installing a heat-sensitive flow sensor in a flow pipe according to an embodiment of the present invention, FIG. 3 is a cross-sectional side view of a conventional heat-sensitive flow rate unit. (1): Insulating tube (2): g temperature resistance t8), lead): lead (4): 4-electro paste (phrase: anti-reflective film (6): tsuba (7): insertion part (8): support part (9): Flow tube (101 Nioriaisu 42 support exclusive use: Fluid flow & In the diagram, the same symbol σ indicates the same or equivalent part. Agent Masuo Oiwa Figure 1 Figure 2 Figure 1) Figure 3 Procedural amendment (voluntary) Name of the invention Thermal flow rate sensor 6 Person making the amendment Representative Hitoshi Katayama Dept., Agent 6 Details of the amendment Page 5 line 4 “Support conductor (12) J and 1, % is corrected to "Support conductor (11) J."

Claims (1)

[Claims] A thermosensitive flow weight detection sensor in which a thin film resistor with temperature dependence tW is formed on the outer surface of an insulating tube, and rod-shaped lead members are inserted into openings at both ends of the insulating tube and fixed at T-. A heat-sensitive drop sensor characterized in that a flange is formed at a predetermined length from one end of the lead member on the insertion side.