JPS6191532A - Fluid temperature measuring apparatus - Google Patents

Abstract

PURPOSE:To reduce measuring errors, by providing a temperature detection rod which has a thermosensitive member at the tip thereof while having a flange-shaped fin and is to be inserted coaxially into an inner cylinder. CONSTITUTION:A part of fluid flowing into a protective cylinder 2 via an inlet opening 2a from the upstream side of a tube wall flows axially through spaces of an inner cylinder 3 and the protective cylinder 2 while the remainder flows axially through the inner cylinder 3 from the opening 3b of the inner cylinder 3 and then, converge to flow out via an outlet opening 2b of the protective cylinder 2. Here, with the action of fins 3c and 3c supporting the inner cylinder 3, the inner cylinder 3 is insulated thermally against the protective cylinder 2 to be almost the same in the temperature as the internal fluid. The thermosensitive member 4a at the tip of the temperature detection bar 4 is also allowed to contact the internal fluid directly to perform a direct heat exchange and becomes almost the same in the temperature as the internal fluid fluid by being shielded from radiant heat with a flange-shaped fin 4b. Then, as the member 4a is shielded double through the inner cylinder 3 and the protective cylinder 2, there is no transmission of radiant heat thereto and the inner cylinder 3 is thermally shielded with the protective cylinder 2 while heat exchange is done with the internal fluid through internal and external surfaces thereby eliminating the possibility of adversely affecting the member 4a.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to fluid temperature measuring devices.

[Conventional technology]

The temperature of the internal fluid is measured when there is a temperature difference between the internal fluid and the pipe wall in the intake and exhaust pipes of internal combustion engines, the piping of refrigerators, etc. 5
As shown in the cross-sectional view, there is a thermocouple inside the protective tube 02.
A detection rod o3 having a temperature sensing portion 03a such as a crystal resistor is installed, a mounting fitting 05 is welded to the pipe 01 to be measured, and a protective tube o2 is fixed to the pipe 01 with a cap nut o6.

Here, 07 is the screw cap for fixing the detection rod Oshi to the protection tube 02, 08 is the gasket to prevent the internal fluid from flowing out, 09 is the output conductor of the detection rod, and 010 is the signal of the detection rod 03. The temperature of the internal fluid is measured as the temperature of the temperature sensing part 03a by an external lead wire leading to the measuring device.

However, when measuring the internal fluid temperature by such means, for example in the exhaust pipe of an internal combustion engine, the outer surface 01
is exposed to the atmosphere, as shown in the model diagram in Figure 6, a part of the heat input 021 to the protective tube 02 is transferred through the protective tube 02 itself as heat 022 due to heat conduction, and the rest is transferred between the inner surface of the tube and the inner surface of the tube. A considerable amount of heat is released to the outside as heat 023 due to radiation of
24 is unavoidable to dissipate, and even if heat is kept, complete insulation is difficult.
Since the metal fittings of 5.06 are exposed, the temperature of the tube wall becomes lower than the temperature of the internal fluid due to heat dissipation.

Furthermore, during measurement, the insertion length of the protective tube varies depending on the type of internal fluid, flow rate, pressure, etc., but it is generally set to be at least 17 times the diameter of the protective tube for the following reasons.

That is, as shown in the model diagram of FIG. 7, when a cylinder 062 is provided protruding from a flat plate 031 and hot air 063 with a temperature higher than that of the flat plate 031 is applied to the cylinder, first, as shown in FIG. When the length of 032 is short, that is, when the insertion length of the protective cylinder is insufficient, the temperature distribution in the axial direction of the cylinder becomes curve 03 with respect to the internal fluid temperature 038 and the inner surface temperature of the flat plate 037.
4, this is because the flat plate 031 has lower crystallinity than the hot air 033 due to convection heat dissipation, and the curve 034 from the cylinder 032.
This is because heat flows out in proportion to the temperature and the temperature becomes low.
A temperature difference 038 occurs at the tip.

Next, if the insertion length of the protective tube is sufficiently long, as shown in the same figure (B), the temperature distribution of the cylinder 032 becomes gentler as it approaches the tip, and approaches the temperature of the hot air 033. , the slope of the curve 034 becomes zero at the tip, and the temperature becomes 038, which is the same as the hot air, so there is no measurement error.

The temperature distribution of the cylinder 062 at that time is expressed by the following equation, and from this relationship, in order to reduce measurement errors, the insertion length of the protective cylinder should be 17 times its diameter, and θ - internal fluid temperature C ℃) θ = Tip temperature of the protection tube C℃) θ = Tube inner surface temperature (temperature at the base of the protection tube) (℃) h = Heat transfer coefficient of the protection tube surface (K cat/m''h''C) P = Protection tube Length (m) λ = heat transfer coefficient (K at/m h '(1) A
H = cross-sectional area of # (wall thickness (m) of δ1-u) t = I/O length (m) However, in reality, the pipe wall is a normal pipe.

In the case of ducts and the like, it is often difficult to secure the necessary insertion length due to problems with the dimensions and the vibration strength of the protective tube.

[Problem that the invention seeks to solve]

The present invention was proposed in view of these circumstances, and it prevents the effects of radiant heat between the protective tube and the tube wall and conductive heat from the protective tube itself to the tube wall, and enables accurate measurement of internal fluid temperature. It is an object of the present invention to provide a fluid temperature measuring device that enables the following.

[Failure to solve the problem]

To this end, the present invention provides a fluid system in which a temperature sensing rod having a temperature sensing member is inserted into the tip of the protective tube by penetrating the tube wall in the lateral direction and inserting the tip of the protective tube into the fluid within the tube over an appropriate insertion length. In a temperature measuring device, an inlet opening is drilled near the closed tip and opens in the upstream direction of the fluid in the tube, and an inlet opening is drilled in a part slightly away from the inlet opening along the insertion length and opens in the downstream direction of the fluid in the tube. A protective cylinder having an outlet opening that opens, and an annular space inside the deep protective cylinder to divide the fluid in the pipe that flows coaxially (C) through the opening opposite to the inlet opening and separate the fluid in the insertion length direction. an inner cylinder whose relatively short end is closed, and a temperature-sensitive member coaxially inserted into the inner cylinder, and a temperature-sensitive member coaxially inserted into the inner cylinder; A temperature detection rod having a flange-like fin protruding from a portion near the tube wall is provided.

[For production]

With such a configuration, it is possible to obtain a fluid temperature measuring device that accurately measures the temperature of the internal fluid while reducing the influence of heat dissipation due to radiation and conduction.

〔Example〕

One embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a longitudinal cross-sectional view thereof, Fig. 2 is a partially enlarged view showing the protection tube in Fig. 1, and Fig. 6 is a diagram taken along z-i in Fig. 2. FIG.

In the above figure, 1 is the tube wall through which the fluid to be measured flows, and 2 is the temperature measurement protection tube according to the present invention, which is inserted laterally into the internal fluid through the tube wall 1, and is located upstream near the closed tip. An inlet opening 2a is formed in the side wall, and an outlet opening 2b is formed in the downstream side wall near the tube wall 1.

3 is a relatively short inner cylinder inserted into the tip of the protective cylinder 2;
Its tip is closed with an end plate 3a, and the inlet opening 2 of the protective cylinder 1
An opening 3b is bored in a portion facing a, and has radial fins 3C protruding from the outer periphery near the opening end at equal intervals, and cooperates with fins 2C protruding from the inner surface of the closed end plate of the protective tube. It is fixed coaxially within the protection tube 1.

4 is a temperature sensing rod located in the center of the inner cylinder 3, and temperature sensing members 4a are inserted into the axis of the protective cylinder 2 and attached at the tip, and are protruded at equal intervals near the temperature sensing member 4a. The inner tube 3 and the protection tube 2 are connected by the radial fins 4C provided and the flange-like fins 4b protruding from a portion slightly closer to the pipe wall than the outlet opening 2b.
is coaxially supported.

5.6.7, 8, 9. iQ is the mounting bracket 051, the cap nut 06°, and the screw cap 07. shown in Figs. 4 and 5, respectively. Patsukin 08. The output conductor 09° is the same structural member as the external conductor 010.

In such a device, a part of the internal fluid flowing into the protection tube 2 from the upstream side of the tube wall 1 through the inlet opening 2a passes through the annular space between the inner tube 3 and the protection tube 2 along the axis of the protection tube. The remaining portion flows in the axial direction through the opening 3b of the inner cylinder 3, joins together, and flows out through the outlet opening 2b of the protection cylinder 2.

At this time, when both the inner and outer surfaces of the inner cylinder 3 come into direct contact with the internal fluid, the inner cylinder 3 is thermally insulated from the protective cylinder 2 due to the action of the fins 3C and 2C that support the inner cylinder 3. , have the same temperature as the internal fluid.

The temperature sensing member 4a at the tip of the temperature sensing rod also comes into direct contact with the internal fluid to directly exchange heat, and the flange-like fins 4b
By shielding radiant heat, the temperature becomes the same as that of the internal fluid.

In this case, the temperature-sensitive member is doubly shielded from the pipe wall, which is lower or higher temperature than the internal fluid, through the inner cylinder and the protection cylinder, so there is no transmission of radiant heat, and the inner cylinder is protected. When heat is shielded by the cylinder, heat is exchanged directly with the internal fluid on both the inner and outer surfaces, so there is no risk of adverse effects on the temperature-sensitive member.

Furthermore, in this device, since the temperature-sensitive member is in direct contact with the fluid being tested, the required insertion length of the temperature detection rod is shorter than that of conventional devices.For example, in a sheathed thermocouple with an outer diameter of 3.2 m/m, The required insertion length is about 60 m/m, which is sufficient, and this allows the entire device to be shortened and small, which is advantageous in terms of structural strength.

〔Effect of the invention〕

In short, according to the present invention, a fluid is produced by penetrating the tube wall laterally, inserting the tip of the protective cylinder into the fluid within the tube over an appropriate insertion length, and inserting a temperature detection rod having a temperature-sensitive member into the tip. In a temperature measuring device, an inlet opening is bored near the closed tip and opens toward the upstream side of the fluid in the tube, and an inlet opening is drilled at a position slightly apart and r'' from the inlet opening along the insertion length and downstream of the fluid in the tube. A protective tube having an outlet opening opening toward the inlet, and an opening coaxially inserted into the protective tube with an annular space therein and facing the inlet opening) separates the inflowing fluid in the tube and separates each into the insertion length. N also has an inner cylinder whose relatively short end is closed, and a temperature-sensitive member inserted coaxially into the inner cylinder, at the end of which the gases guided in the direction meet and flow out through the outlet opening. The present invention is industrially extremely useful because it provides a fluid temperature measuring device with less measurement error by providing a temperature sensing rod with flange-like fins protruding from the outlet opening near the pipe wall.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing one embodiment I9u of the present invention, FIG. 2 is a partially enlarged view showing the protection tube of FIG. 1, and FIG. 4 is a longitudinal sectional view showing a known fluid temperature measuring device; FIG. 5 is a lateral sectional view of FIG. 4;
This figure is a model diagram showing the heat wave state during protection in FIG. 5, and FIG. 7 is a model diagram showing the temperature distribution of the protection tube in FIG. 4. 1... Pipe wall, 2... Protective tube, 2a... Inlet opening, 2
b... Outlet opening, 2C... Fin, 3... Inner cylinder, 3
a... End plate, 3b... Opening, 3c... Fin, 4
...Temperature detection rod, 4a...Temperature sensing member, 4b...Flanged fin, 4G...Fin, 5...Mounting bracket,
6... Bag nut, 7... Screw cap, 7a... Nokusokin, 7b... Patchkin, 8... Patchkin, 9...
Output conductor, 10...external conductor. Sub-Agent Patent Attorney Masaru Tsukamoto Letter Box Figure 7 Figure 2 Figure 3

Claims (1)

[Scope of Claims] Fluid temperature obtained by penetrating the pipe wall laterally, inserting the tip of the protective tube into the fluid within the tube over an appropriate insertion length, and inserting a temperature detection rod having a temperature-sensitive member into the tip. In the measuring device, an inlet opening is drilled near the blocked tip and opens toward the upstream side of the fluid in the tube, and an inlet opening is drilled at a location slightly apart from the inlet opening along the insertion length and opens toward the downstream side of the fluid in the tube. A protective cylinder has an annular space and is coaxially inserted into the protective cylinder, and the fluid flowing into the pipe is separated from the opening facing the inlet opening, and the fluid is guided in the insertion length direction. an inner cylinder whose relatively short end is closed for merging and flowing out through the outlet opening, and a temperature-sensitive member coaxially inserted into the inner cylinder at the tip, and a tube wall of the outlet opening. 1. A fluid temperature measuring device comprising: a temperature detection rod having a protruding flange-like fin at a closer portion thereof.