JPH0439577Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fluid velocity measuring probe that measures the flow velocity of various liquids and gases or the moving velocity of particles and powder. and also relates to something that makes it possible to measure the direction of fluid flow.

[Conventional technology]

Germanium has a temperature-resistance characteristic in which the resistance value decreases according to a constant function when the temperature exceeds a certain temperature range.

The fluid velocity measurement probe of Japanese Patent Application No. 59-207780 and Utility Application No. 61-57682 uses this temperature-resistance characteristic to maintain a constant temperature by applying voltage to a sensor made of a small piece of germanium single crystal. The velocity of the fluid is measured by raising the temperature and converting the resistance value that changes with the temperature change due to contact with the fluid into current, voltage, or power, and measuring this.

Of the above fluid velocity measurement probes, the application was made in 1983.
As shown in the example of No. 57682,
As shown in Fig. 4, a rectangular parallelepiped sensor a made of a small piece of germanium single crystal is mounted on the upper end surface of a support b made of an inorganic material such as ceramic, glass, or synthetic resin, which is an electrical insulator and has excellent heat insulation properties.
The central part of the side surface in the length direction is fixed with an adhesive or the like, and both sides of the support b are sandwiched between highly conductive metal supports c, and the lower end surface of the support b is sufficient to absorb the force of the fluid. There is a probe for measuring fluid velocity that is erected on the upper surface of a base d made of electrically insulating material with a durable thickness.

[Problem that the invention attempts to solve]

The above-mentioned probe for measuring fluid velocity has some difficulties in measuring the direction of fluid flow.

This is thought to be because the sensor of the fluid velocity measurement probe responds uniformly to the direction of the fluid, and the output value changes little with respect to the direction of the fluid.

Therefore, in view of the above problems, the present invention changes the output of the sensor according to the direction of the fluid flow around the longitudinal axis of the support b, thereby making it possible to measure the direction and velocity of the fluid. The present invention aims to provide a speed measurement probe.

[Means for solving problems]

In order to achieve the above purpose, a support is erected on the top of the base, and a length of a sensor made of a small piece of germanium single crystal in the shape of a rectangular parallelepiped is attached to the upper end of a roughly rod-shaped support made of an electrical insulator that is attached to the support. A synthetic resin layer is formed on one side surface in the length direction adjacent to the side surface to which the sensor support is fixed, and a voltage is applied to the sensor to control the fluid flow. Converts the resistance value that changes due to temperature change due to contact with the device into a change in current, voltage or electric energy,
A fluid velocity measurement probe for measuring the velocity of a fluid is provided.

[Effect]

As mentioned above, a synthetic resin layer is formed on one side in the length direction of the sensor, and the side on which the synthetic resin layer of the sensor is formed is formed in the direction of fluid flow with the longitudinal direction of the support as an axis. This makes it possible to measure the direction of fluid flow and also the velocity of the fluid based on the varying output.

〔Example〕

An embodiment of the fluid velocity measuring probe of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory perspective view of an embodiment of a probe for measuring fluid velocity according to the present invention.

In the figure, 1 is a sensor made of a germanium single crystal in the form of a rectangular parallelepiped. Highly conductive metal pieces such as gold, silver, copper, or platinum are fixed to both ends of one side 2 in the length direction of the sensor 1, and electrodes 3a , 3b, and lead wires 4a, 4b connected to the side surfaces of the support body or pillars, which will be described later, are drawn out from the electrodes 3a, 3b, and the electrodes 3
A synthetic resin layer 5 is provided on the entire side surface 2 in the longitudinal direction adjacent to the side surface 2 having the side surfaces a and 3b.

This synthetic resin layer 5 is made by coating synthetic resins such as epoxy resin, silicone resin, aniline resin, phenol resin, polyester resin, and urethane resin.The reason for adopting these synthetic resins is based on the experimental results described below. Ordained.

Reference numeral 6 denotes a rod-shaped support whose upper end is fixed to the center of the surface of the sensor 1 on which the electrodes 3a and 3b are provided via an adhesive layer 7, and the support 6 is an electrically insulating material and has excellent heat insulation properties. It is made of ceramic in the form of a rod.

However, other inorganic materials such as glass or synthetic resins may also be used.

8a and 8b are columns made of metal cylinders such as stainless steel with high conductivity and low possibility of corrosion, which are erected parallel to the base 9, and the lower ends of the supports 6 are slightly below the upper ends of these columns 8a and 8b. The support body 6 is fixed to the pillars 8a and 8b together with the lead wires 4a and 4b by adhesive or soldering with a conductive adhesive.

The base 9 is for fixing the columns 8a and 8b, and has a cylindrical shape with a flat upper end surface, and the inside of the base 9 is for fixing the columns 8a and 8b.
A wire rod is provided to be connected to a and 8b.

However, the supports 8a and 8b are used to further improve measurement accuracy, and depending on the type of fluid and flow rate, it is necessary to firmly support the support body 6. In that case, they may be formed integrally with the base 9. will be considered.

With this configuration, the fluid velocity can be detected in all directions from around the support 6, and the resistance value at both ends of the sensor 1 can be divided in the center of the sensor 1. Eliminate variations and reduce measurement errors.

To explain the current path of the fluid velocity measurement probe, when a voltage is applied between the electrodes 3a and 3b of the sensor 1, the current path is from the column 8a to the lead wire 4a to the sensor 1, and the return path is from the sensor 1 to the lead wire 4.
Flows from b to pillar 8b.

Next, the thermal path will be explained. When a voltage is applied, the sensor 1 generates resistance heat and is heated up.

This resistance heat passes through the support 6 to the pillars 8a and 8b.
The temperature of the sensor 1 decreases due to heat conduction, which causes errors in flow velocity and direction measurements.
This is prevented by making the contact surfaces of a and 8b as small as possible.

Reducing this error means increasing the response speed to changes in airflow speed.

Further, when the direction of the fluid is set from below the support columns 8a and 8b toward the sensor 1, the fluid may be concentrated by the surface of the support body 6 and guided to the bottom surface of the sensor 1. As usual, pillar 8
When a space for fluid passage is formed between a and 8b, the fluid passes toward the rear of the device, preventing intensive guidance by the surface of the support 6, and causing measurement errors due to the direction of fluid flow. prevent.

Experiments using the above probe are shown below.

First experimental example In the first experimental example, the configuration of the probe used is as follows:
Sensor 1 uses germanium single crystal 0.6mm x 0.6mm x
The support 6 was formed into a 4 mm approximately rectangular parallelepiped.
The length is 5mm, and the diameter of struts 8a and 8b is 0.5mm, and the length is 6.5mm.
mm, and the synthetic resin layer 5 is made of epoxy resin.

Using a series resistance circuit connected to the sensor through a 400Ω resistor with a power supply voltage of 30V shown in Figure 2a, the airflow velocity was varied from 1 to 10m/s under the condition that the airflow temperature was constant at 21℃. , the terminal voltage of sensor 1 is plotted on a graph as shown in FIG. 2c.

However, as shown in FIG. 2b, the case where the airflow comes at right angles to the surface of the synthetic resin layer 5 of the sensor 1 is referred to as A, and the airflow comes at right angles to the surface facing the synthetic resin layer 5. Case B is the case, and case C is the case where the light comes at right angles to the end face 10.

From this wind speed-output voltage characteristic diagram, the output of C appears to be the smallest, and the output of A is larger than the output of B, which means that case A cools better than case B.

This seems to be due to the fact that the influence of the airflow that forms a spiral and hits the back surface is greater than the influence of the airflow that hits the synthetic resin layer 5 directly.

In any case, it can be seen from the experimental results that it is possible to distinguish from the characteristic diagram in FIG. Ta.

Further, FIG. 2d is an output characteristic diagram when the angle between the plane perpendicular to the longitudinal direction of the support 6 and the direction of fluid flow is set to 30 degrees.

From this output characteristic diagram, even when the direction of fluid flow has an inclination in the axial direction of sensor 1, there is a difference in the magnitude of the output at least when the inclination angle is 30 degrees, but it is almost the same as that of the fluid flow. It has been found that the direction can be distinguished as rear, front, or side with respect to the side surface on which the synthetic resin layer 5 is formed.

In addition, as a result of using other materials as the material of the synthetic resin layer 5, although the magnitude of the output was different, the characteristics were generally similar.

Second Experimental Example Figure 3a shows the probe used in the experiment, rotated around the length direction of the support 6 in an airflow at a constant speed (5 m/s), and the rotation angle taken as the horizontal axis. , the voltage between the terminals of sensor 1 was plotted with the output voltage as the vertical axis.

However, the angle at which the airflow arrives perpendicularly to the end face 10 is set to 0 degrees, the side that rotates counterclockwise is defined as the minus side, and the side that rotates clockwise is defined as the plus side.

From Fig. 3a showing the experimental results, the output characteristics are approximately symmetrical with respect to 0 degrees, but the side where the airflow arrives at the side where the synthetic resin layer 5 is formed (-90 degrees to 0 degrees)
It is determined that the output is slightly larger than the output on the side (0 degrees to 90 degrees) where the airflow arrives at the side surface opposite to the side surface on which the synthetic resin layer 5 is formed.

In addition, Fig. 3 is an enlarged view of Fig. 3 a near 0 degrees.
Shown in Figure b.

Figure 3c is the same as in Figure 3a, with the angle between the plane orthogonal to the axis of the support 6 and the direction of fluid flow set to 30 degrees. 2 is an output characteristic diagram rotated around the longitudinal direction of the support body 6. FIG.

According to FIG. 3c, the output characteristic curve is slower than that in FIG. 3a, but the directional characteristics can be determined sufficiently.

From Experimental Examples 1 and 2 above, by forming the synthetic resin layer on one side, it was possible to obtain an output that varied with the direction of the airflow, making it possible to measure the wind speed as well as the wind direction.

In addition, since the sensor 1 is made of a small piece of germanium single crystal, it is more durable than a hot wire anemometer. 5, it goes without saying that the speed and direction of conductive fluids such as water can also be measured.

[Effect of idea]

The probe for measuring fluid velocity according to the present invention as described above has a synthetic resin layer formed on one side surface in the length direction of the sensor, and the synthetic resin layer has a structure in which the fluid coming towards the synthetic resin layer and the fluid coming towards the other side surface are separated from each other. By changing the output with the incoming fluid, it is possible to measure which direction the fluid is coming from, and also measure the velocity of the fluid.

In addition, as shown in the example, by sandwiching the support between two pillars and reducing the contact area between the support and the pillars, the heat of the sensor is prevented as much as possible from escaping to the pillars, and the fluid velocity is reduced. Measurement errors can be reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the probe for measuring fluid velocity according to the present invention, Fig. 2a shows the series resistance circuit used in the experiment, and Fig. 2b shows the direction of fluid flow in which the experiment was conducted. Explanatory diagram, Fig. 2c is a fluid velocity-output voltage characteristic diagram, Fig. 2d is a fluid velocity-output voltage characteristic diagram with the sensor tilted at 30 degrees with respect to the fluid flow direction, and Fig. 3a is a fluid velocity-output voltage characteristic diagram. is a rotation angle-output voltage characteristic diagram when the support is rotated around the length direction of the support, and FIG. 3b is a rotation angle-output voltage characteristic diagram that is an enlarged view of the vicinity of the rotation angle of 0 degrees in FIG. 3a. Figure 3c is a rotation angle-output voltage characteristic diagram when the sensor is rotated around the length direction of the support with the sensor tilted 30 degrees to the direction of fluid flow, and Figure 4 is the conventional It is a perspective view showing an example. DESCRIPTION OF SYMBOLS 1...Sensor, 2...Side surface, 3a, 3b...Electrode, 4a, 4b...Lead wire, 5...Synthetic resin layer, 6...Support, 7...Adhesive layer, 8a, 8b
... Support column, 9 ... Base, 10 ... End surface.

Claims (1)

[Claims for Utility Model Registration] 1. A sensor in which a column is erected on the top surface of a base, and a small piece of germanium single crystal is placed in the shape of a rectangular parallelepiped on the upper end surface of a substantially rod-shaped support made of an electrical insulator that is attached to the column. A central part of one side surface in the length direction is fixed, a synthetic resin layer is formed on either side surface in the length direction adjacent to the side surface to which the sensor support is fixed, and a voltage is applied to the sensor. A fluid velocity measurement probe that measures the velocity of a fluid by converting the resistance value that changes with temperature changes due to contact with the fluid into changes in current, voltage, or electric power. 2. The fluid according to claim 1 of the utility model registration claim, in which the pillars are two metal pillars of good electrical conductivity that are erected in parallel and spaced apart from each other on the upper surface of the base, and a support body is sandwiched between the pillars. Probe for speed measurement.