JPS59226871A - Pressure measuring device - Google Patents

Abstract

PURPOSE:To measure a pressure with a high accuracy by turning a Pitot tube by a stepping motor, and detecting optically a small hole which turns as one body. CONSTITUTION:A Pitot tube 31 fixed to a supporting part 33 is turned by a stepping motor coupled with the supporting part 33. Subsequently, a reference angle detecting small hole 37 provided on a disk 35 formed as one body with the supporting part 33 is detected by a photosensor, the reference direction is determined exactly, and a pressure measurement can be executed with a high accuracy by subsequent exact turning and positioning by the stepping motor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pressure measuring device using a pitot tube for measuring the magnitude and direction of flow velocity.

Conventional configuration and problems thereof Conventionally, a pitot tube for measuring the velocity vector of a flow has been configured as shown in FIG.

That is, reference numeral 1 denotes a pitot tube, which is composed of a small hole 2 for introducing pressure, a pointer part 3 for determining the rotation angle of the small hole 2 from a reference plane, and a pressure extraction end part 4. Further, numeral 5 denotes a disk portion having an angle scale carved thereon, which also serves as a holding portion for smoothing the rotation of the pitot tube 1. The following procedure was used to measure the velocity vector using the Pitot tube shown in FIG.

That is, the pitot tube inserted into the flow is rotated 3600 times,
Aim at the position where the pressure from the small pressure introducing hole 2 shows the maximum value P2, that is, in the direction of the flow V as shown in Figure 2 a, and read the rotation angle ε of the small hole 2 from the reference plane and the pressure P2 at that point. .

Next, as shown in Fig. 2c, the pitot tube is rotated in the forward and reverse directions by a certain angle Δε, and the pressure P1. Read each P3. and three pressures P1
．． The direction and magnitude of the flow can be determined from P2°P3 and angle ε.

However, when measuring the flow velocity using the pitot tube having the conventional configuration, the angle reading tends to be inaccurate and takes a long time. Furthermore, in order to improve the accuracy of the angle, it is necessary to increase the size of the disk portion 5, which also serves as a pitot tube holding portion, which increases the size of the entire fruiting device, which poses a problem in measuring fine details.

Conventionally, when determining the absolute origin that serves as a reference when measuring the rotation angle of the pressure introduction hole of a Pitot tube as shown in Figure 1, it is necessary to place the Pitot tube in a flow of known size and direction. After insertion, the pressure introduction hole was oriented in the direction of flow, and the direction in which the pressure was maximum was set as the absolute origin, that is, the reference direction. However, near the reference direction, the change in pressure with respect to changes in the rotation angle is very small, so the method of determining the reference direction is inaccurate, and the measured pressure direction always includes a deviation from the absolute reference direction. was.

As mentioned above, in the pitot tube pressure measuring device having the conventional structure, it is difficult to measure the flow with high precision, and the measurement efficiency is low because time is consumed in reading the angle.

OBJECTS OF THE INVENTION In order to solve these conventional problems, the present invention attaches a pitot tube to a stepping motor shaft, accurately and quickly measures the rotation angle from a reference direction, and provides a pitot tube support disk. The purpose is to accurately set the absolute reference direction of the Pitot tube pressure introduction/hole using the reference angle detection small hole drilled in the hole and the photo sensor.

Structure of the Invention In order to achieve this object, the present invention provides a stepping pipe in which the open end of the pipe having a fluid pressure inlet hole near the closed end is communicated with a pressure outlet provided in the support. Connected to the motor shaft. On the stepping motor side of the human tube support part, there is a reference angle detection small which has a recess in a plane that includes the center axis of the pressure introduction hole and the pitot tube center axis, and whose center axis is parallel to the pitot tube center axis. A disc with holes and a photosensor that detects the holes were biased.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, 31 is a pitot tube, 32 is a small pressure introduction hole, 33 is a pitot tube support part, 34 is a pressure outlet,
35 is a disc provided with a small hole 37 for detecting a reference angle. Here, the reference angle detection small hole 37 is located within a plane including the central axis of the pressure introduction small hole 32 and the central axis of the pitot tube 31, and has a central axis parallel to the central axis of the pitot tube 31. A hole is provided near the outer periphery of the disc 35.

In Fig. 4, -41 is the stepping motor, 42 is the stepping motor mounting stand, 43 is the photosensor consisting of a light emitting part 44 and a light receiving part 46, 47 is the photosensor mounting stand, and 46 is the stepping motor shaft. be.

Here, the photosensor 43 is connected to the stepping motor shaft 4.
The pressure obtained through the pressure introduction hole 32 is installed so that the optical axis passes through the reference angle detection hole 37 in a horizontal or vertical plane that includes the center line of 6. The pressure is guided to a pressure transducer such as a manometer through the outlet 34 and a tube, and is measured.

By using the pressure measuring device configured in this manner, the rotation angle of the pitot tube from the reference direction can be accurately and quickly read using the step angle of the stepping motor as the limit of resolution. Further, since the forward and reverse rotation speed through a certain predetermined angle Δε is fast, the pressure measurement time can be shortened.

Further, a small reference angle detection hole 37 is optically located in a plane including the central axis of the pressure introduction hole 32 of the pitot tube and the central axis of the pitot tube, and has a central axis parallel to the central axis of the pitot tube. By detecting the pressure by the means, the small pressure introduction hole 32 of the shibito tube can be initialized accurately and easily in the absolute reference direction.

For example, the absolute reference direction is accurate in the horizontal or vertical direction by the signal of a photosensor installed so that the optical axis passes through the reference angle detection small hole 37 in a horizontal or vertical plane that includes the central axis of the stepping motor. Initial settings can be easily made.

Even if the pitot tube is removed from the motor shaft, the pitot tube 31 and the small hole 37 for detecting the reference angle in the support disk are integrated, so there is no deviation in the reference direction and the reproducibility is very good. .

Furthermore, since a stepping motor is used, rotation angle control can be easily configured with a pulse signal generator, and it can also be applied to an automatic flow measurement device using a computer or the like.

Effects of the Invention As described above, according to the pressure measuring device of the present invention, it is possible to accurately control the rotation angle of the pipe from the reference direction according to the step angle of the stepping motor, thereby achieving highly accurate measurement. It can be done quickly.

Furthermore, by detecting the reference angle detection small hole with a photosensor, the absolute reference origin of the pressure introduction hole can be initialized with high accuracy. Furthermore, since the small hole for detecting the reference angle and the pitot tube are made of an integrated structure, even if the pitot tube is removed from the motor shaft, the absolute reference origin will not shift and it can always be installed in the same reference direction with the same accuracy. .

Furthermore, since the rotation can be controlled using pulse signals, it can also be applied to automatic flow measuring devices using a controller such as a computer.

[Brief explanation of the drawing]

FIG. 1a is a schematic front view of a conventional pitot tube pressure measuring device;
2 is a side view, FIGS. 2 a, b, and c are sectional views showing the rotational direction of the pressure introduction hole of the pitot tube. FIGS. 3 a, b are pressure measuring devices according to an embodiment of the present invention. side view, front view, 4th
The figure is a side view of the same pressure measuring device. 31... Pitot tube, 32... Pressure introduction hole,
33...Pitot tube support part, 34...Pressure outlet, 37...Reference angle detection/J hole, 41...
Stepping motor, -ta, 43...- Photo sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure (L) (b) Figure 2 ((L) (b)
(C) Figure 3 (α) (b)

Claims (2)

[Claims] (1) A pressure measuring device in which a pitot tube, which has a small hole for introducing fluid pressure near the closed end and the open end of the other end of the pipe communicates with a pressure outlet provided in the support, is connected to the Stella Pink motor shaft. . (2) On the stepping motor side of the pitot tube support section, there is a pressure measuring device that has a central axis parallel to the pitot tube central axis on a plane that includes the central axis of the small pressure introduction hole and the pitot tube central axis.