JP3022618B2 - Fluid pressure detector, flow rate measuring method, flow rate measuring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure detecting device and a flow rate measuring method and a flow rate measuring method using the fluid pressure detecting device.

[0002]

2. Description of the Related Art Here, a prior art relating to a fluid pressure detecting device in a fluid transporting device for air, dry nitrogen, hydrogen, etc. will be described. In particular, here, the flow rate in the pipe of the fluid transport apparatus is generally measured by using a flow rate measuring apparatus using an orifice plate (a disc with a hole provided in the pipe). In this case, a pressure outlet is provided before and after the orifice plate, and the flow rate is calculated from the pressure difference between before and after. In this case, since the pressure is measured with a pressure gauge through a pipe connected to the pressure outlet from the front and rear pressure outlets, the structure of the detection device is complicated, transport and installation are not easy, and it is difficult to make it light and thin. was there.

[0003] When a fluid transport device is installed outdoors, it is necessary to measure the flow of the outside air (air flow) around the fluid transport pipe. In this case, a hot wire (hot wire) flow meter is used near the pipe. Measure the flow rate. In this case, the hot wire is extremely thin, about 5 μm, very weak, and has a disadvantage that it is easily broken. Further, the hot wire is liable to be consumed due to oxidation or the like due to an increase in temperature, and thus has a disadvantage that its life is short. Further, since it takes time to calibrate the flow velocity meter, there is a problem that the measurement takes time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional drawbacks and disadvantages, and is mounted on a fluid transport device to measure a flow rate of a fluid flowing through a circular pipe. It is possible to measure the flow velocity and pressure of the wind flowing around the circular pipe as a single fluid pressure detection device. It is an object of the present invention to provide a fluid pressure detecting device having a simple structure having a long service life and a flow rate measuring method and a flow rate measuring method using this device.

[0005]

According to the present invention, there is provided a fluid pressure detecting device having a circular pipe shape, wherein a hole penetrating between an outer peripheral surface and an inner peripheral surface of the circular tube is formed, and the hole is closed. A pressure sensor is provided in the hole so that an outer peripheral end of the pressure sensor constitutes a pressure detector outside the circular tube, and an inner peripheral end of the pressure sensor is formed of the circular tube. The present invention relates to a fluid pressure detecting device which constitutes an inner pressure detecting section and detects pressure on the outer peripheral surface side and / or the inner peripheral surface side of the circular tube by the pressure sensor.

Here, an orifice plate is provided inside the circular tube so as to be perpendicular to the axis of the circular tube, and the holes and the pressure sensors are provided on the front side and the rear side of the orifice plate, respectively. You may do it. Further, it is preferable that the holes are arranged on the circular pipe at positions spaced apart by 45 ° ± 10 ° in the circumferential direction. Further, the flow rate of the fluid flowing through the circular pipe may be measured from the pressure difference between the output pressures of the pressure sensors on the front and rear sides of the orifice plate of the fluid pressure detecting device. Alternatively, the outer peripheral surface of the circular tube of the pressure sensor of the fluid pressure measuring device is vertically opposed to the flow direction of the fluid, and the total pressure is measured from the hole on the front side and the static pressure is measured from the hole on the rear side. The flow rate may be measured from.

[0007]

As described above, a hole penetrating between the outer peripheral surface and the inner peripheral surface of the circular pipe is formed, and a pressure sensor is provided in this hole.
By providing an orifice plate and arranging holes provided with the pressure sensors on the front side and the rear side of the orifice plate, it is also possible to measure the flow rate of the fluid flowing in the circular pipe by using the fluid transport device. This makes it possible to collect a device capable of measuring the flow velocity and pressure of a wind flowing around a circular pipe of a fluid transport device as one fluid pressure detecting device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. In addition, the same reference numerals are given to the corresponding common parts in the respective drawings, and redundant description is avoided as much as possible. 1 is a top view, FIG. 2 is a front sectional view, and FIG. 3 is a bottom view. The fluid pressure detecting device includes a circular pipe 1 and an orifice plate 2. Pipe 1
Is a double tube of the outer cylinder 1a and the inner cylinders 1b and 1c, which are concentric. The axis is indicated by reference numeral 3. The orifice plate 2 is sandwiched between the outer periphery of the outer tube 1a of the circular tube 1 and the ends of the inner tubes 1b and 1c so that the orifice plate 2 is perpendicular to the axis 3 of the circular tube 1. Is provided. The orifice plate 2 is generally a perforated disk provided in a pipe for measuring a flow rate, but is also used here for measuring a fluid pressure and a flow velocity. Holes (in the normal direction) 4 and 5 penetrating between the outer peripheral surface and the inner peripheral surface of the circular tube 1 are formed. A hole 4 is formed in the circular tube 1 on the front surface 2a side of the orifice plate 2, and
A hole 5 is formed in the circular tube 1 on the rear surface 2b side of the orifice plate 2. In these holes 4 and 5, pressure sensors 6 and 7 composed of electromechanical elements such as semiconductor sensors and piezoelectric elements for detecting pressure are arranged.

As shown in FIGS. 1 and 3, these holes 4 and 5 are located at an angle of 45 degrees from each other in the circumferential direction of the outer peripheral surface of the circular tube 1. The diameter of the holes 4 and 5 is, for example, 1.5 m
m. Further, lead wire grooves 8 and 9 communicating with the holes 4 and 5 in the same direction as the shaft core 3 are provided on the bonding surface side between the outer cylinder 1a and the inner cylinders 1b and 1c. The assembling procedure is as follows. First, the orifice plate 2 is mounted inside the outer cylinder 1a of the circular pipe 1, and the holes 4,
Place between 5 Next, pressure sensors 6 and 7 for detecting pressure are provided, and are adhesively fixed to the holes 4 and 5, so that the holes 4 and 5 serve as partition walls. These pressure sensors 6, 7
The lead wires 10 and 11 are taken out along the lead wire grooves 8 and 9 as shown in FIG. Next, the inner cylinders 1b and 1c of the circular tube 1 are slid along the bonding surface of the outer cylinder 1a, and the orifice plate 2 is moved to the inner cylinders 1b and 1c.
Adhesively fix them so that they are sandwiched between them. Thus, the circular tube 1 and the orifice plate 2 are completely fixed.

Next, the holes 4 and 5 will be described a little more. Although it is a hole where the pressure sensors 6 and 7 are arranged, it is a complete partition wall, and no fluid flows or leaks from 4a and 5a to 4b and 5b. That is, the holes 4 and 5 correspond to the pressure sensor 6,
7 is a partition wall through which fluid cannot pass. In addition, after passing through the lead wires 10, 11, the lead wire grooves 8, 9 are also sealed with synthetic resin or the like, so that fluid does not flow. Therefore, both the outer peripheral side 4a, 5a and the inner peripheral side 4b, 5b of the holes 4, 5 are in contact with the fluid on the outer peripheral side and the inner peripheral side of the circular tube 1, respectively, and the pressure sensors 6, 7 sense the pressure from both sides. Can be done.

An example of the specification dimensions of the fluid pressure detecting device described above is shown below. 1.5 mm diameter of holes 4 and 5 External dimensions of circular tube 1 60 mm Inner diameter size of circular tube 1 50 mm Thickness (plate thickness) of orifice plate 2 5 mm Hole diameter of orifice plate 2 30 mm Hole 4 and hole 5 Distance 45 degrees The outer cylinder 1a, the inner cylinders 1b and 1c, and the orifice plate 2 are made of, for example, stainless steel.

The operation of the present invention will be described with reference to FIGS. FIG. 4 is an operation principle diagram of the present invention, and FIG. 5 is a pressure distribution diagram of the present invention. FIG. 4 shows a state in which the fluid 12 flows around the outer circumference of the circular tube 1 described with reference to FIGS. In FIG. 4, the flow of the fluid 12 is as follows. First, a pressure sensor 7 disposed in the hole 5 is disposed at a position where the pressure is vertically sensed, and the pressure sensor 7 is separated from the outer peripheral surface of the circular pipe 1 by a circumferential angle of 45 degrees. The pressure sensor 6 disposed in the hole 4 is disposed at a different position. Where 12a, 12
b indicates a flow around the outer peripheral surface of the circular tube 1, and 12c indicates a wake.

The arrows of the fluid 12 indicate the direction of the flow to be measured. The pressure sensor 7 detects the pressure at the position of 0 degree, and the pressure sensor 6 detects the pressure at the position shifted by 45 degrees. I do. FIG. 5 shows the pressure distribution when the position is shifted from the 0 degree position to 180 degrees in the circumferential direction of the circular tube 1 (the position of the wake 12c). The position of the fluid 12 is 0 degree, the position of the flow 12a, 12b on the outer peripheral surface of the circular pipe 1 at a right angle is 90 degrees,
The measured values are shown in this figure with the position of 12c being 180 degrees. The horizontal axis represents the angle, and the vertical axis represents the pressure coefficient. The total pressure of the pressure detected by the pressure sensor 7 P _O, the pressure sensor 6
Is used as the static pressure P _S , and the pressures detected by the pressure sensors 6 and 7 are converted into electric signals and input to an arithmetic circuit such as a CPU (not shown), and the velocity V of the fluid is calculated from Equation 1. Ask by The obtained speed V is displayed, for example, digitally (not shown). Assuming that the density of the fluid is ρ, the velocity V of the fluid is expressed by Equation 1.

[0014]

(Equation 1) Further, the static pressure P of the dynamic pressure detected by total pressure P _O and the pressure sensor 6 measured by the pressure sensor 7 when When P _D and dynamic pressure P _D
It can be obtained from the difference from _S (P _D = P _O −P _S ). FIG. 6 shows an example in which the fluid pressure detecting device of the present invention is actually connected to external fluid pipes 13 and 14 as a fluid transport device. With this fluid transport device, the flow rate can be measured. FIG.
5 is based on the principle of using the outer peripheral surface of the circular tube 1, but in FIG. 6, the flow rate of the fluid flowing through the inner peripheral surface, that is, the inner cylinders 1b and 1c of the circular tube 1 is determined by an orifice. Determined by using the plate 2 and 6 and 7. Here, a gas such as air or dry nitrogen is used as the fluid, but is not limited to a gas, and a fluid, heated steam, or the like may be used. 6, the external fluid pipes 13 and 14 are fastened to both ends of the fluid pressure detection device via packings 15 and 16 with high tension bolts and nuts. In this case, the lead wires 10 and 11 of the pressure sensors 6 and 7 are taken out of the circular tube 1 while being pressed by the packing.

Next, the operation is as follows.
12 flows upstream, passes through the fluid pressure sensing device, and transports the fluid 12c downstream through the external fluid line 14. Here, the flow rate of the fluid is measured by the fluid pressure detecting device, and the flow rate Q is expressed by Expression 2.

[0016]

(Equation 2)That is, here, m = 0.6, α = 0.74, and D = 50 mm.
Determined from the above specifications, ε (compression coefficient) is P₁, P_Two
Is determined when the value of ₁, P_Two
The flow rate can be measured by detecting. Then, P
₁, P_TwoIs detected on the inner peripheral side of the pressure sensor 6 in the hole 4.
Pressure P from 4b₁The hole 5 on the inner peripheral side 5b of the pressure sensor 5
The pressure of the incoming fluid is P_TwoAnd these pressure sensors 6,
7. Convert the measured value of the pressure measured by 7 into an electric quantity,
Input to an arithmetic circuit such as a CPU (not shown),
To obtain the flow rate Q of the fluid by calculation. This flow rate Q
Digital display, for example, by a display (not shown)
It has become.

As described above, the pressure and flow velocity of the fluid outside the circular tube 1 can be measured by the same pressure detecting device as described with reference to FIGS. 4 and 5, and FIG. As described above, it is possible to measure the flow rate of the fluid flowing inside the circular tube 1. The feature here is
In particular, detected by the pressure sensors 6 and 7 the external flow of circular tube 1 from the respective holes 4 and 5 as the total pressure P _O static pressure P _S, and the pressure inside the flow of circular tube 1 through the hole 4 and 5 P ₁ , P ₂
Are measured by the pressure sensors 6 and 7. According to this principle, the holes 4 and 5 and the pressure sensors 6 and 7 are the same, and the pressures 6 and 7
Serves as a partition. The same pressure sensors 6 and 7 can measure pressure, flow velocity and flow rate. The pressure detecting device has a simple structure and is inexpensive and durable. Although the measurement method of measuring the flow rate of the fluid transport device and the pressure of the air flowing around the fluid transport device and the flow velocity have been described above,
It can also be used to measure pressure and flow velocity in ducts and wind tunnels using the outer peripheral surface of a circular pipe.

In the above description, the interval between the holes 4 and 5 has been described as 45 degrees. However, as can be seen from the pressure distribution diagram in FIG.

[0019]

As described above, one aspect of the present invention is as follows.
In a fluid pressure detecting device having a circular tube shape, a hole penetrating between an outer peripheral surface and an inner peripheral surface of a circular tube is formed, and a pressure sensor is provided in the hole so as to close the hole. The outer peripheral tip of the pressure sensor constitutes a pressure detector outside the circular tube, and the inner peripheral tip of the pressure sensor constitutes a pressure detector inside the circular tube. The pressure on the surface side and / or the inner peripheral surface side is detected.
Therefore, according to such a configuration, the pressure on the outer peripheral surface side and the inner peripheral surface side of the circular tube are both reduced by the pressure sensor disposed in the circular tube so as to close the hole. It becomes possible to detect. Also, by providing an orifice plate in the circular pipe, and through holes in the wall of the circular pipe on the front and rear sides of the orifice plate, by disposing the above pressure sensor in each through hole, In addition to being able to measure the flow rate of the fluid flowing through the fluid pipe in the fluid transport device, it is also possible to measure the flow velocity and pressure of the flow of the wind flowing around the fluid pipe of the fluid transport device. It is possible to assemble as one fluid pressure detecting device that can be performed, and to realize a fluid pressure of a simple configuration that is lightweight, short, small and highly reliable, and a flow rate measuring method and a flow rate measuring method using this device. Can be provided.

[Brief description of the drawings]

FIG. 1 is a top view of an embodiment of a fluid pressure detecting device according to the present invention.

FIG. 2 is a front sectional view of FIG.

FIG. 3 is a bottom view of FIG. 2;

FIG. 4 is an operation principle diagram of the present invention.

FIG. 5 is a pressure distribution diagram of the present invention.

FIG. 6 is a cross-sectional view when the fluid pressure detecting device of the present invention is assembled to a fluid transport device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circular tube 1a Outer cylinder 1b, 1c Inner cylinder 2 Orifice plate 3 Shaft core 4, 5 hole 6, 7 Pressure sensor 8, 9 Lead wire groove 10, 11 Lead wire 12 Fluid 12a, 12b Flow of outer peripheral surface of circular pipe 12c Wake 13, 14 External fluid pipe

Claims (5)

(57) [Claims] In a fluid pressure detecting device having a circular pipe shape, a hole is formed through a hole between an outer peripheral surface and an inner peripheral surface of the circular tube, and a pressure is formed in the hole so as to close the hole. A sensor is provided, and an outer peripheral end of the pressure sensor constitutes a pressure detecting unit outside the circular tube, and an inner peripheral end of the pressure sensor constitutes a pressure detecting unit inside the circular tube. And
A fluid pressure detecting device, wherein the pressure sensor detects a pressure on an outer peripheral surface side and / or an inner peripheral surface side of the circular tube. 2. The pressure measuring device according to claim 1, wherein an orifice plate is provided inside the circular tube so as to be perpendicular to the axis of the circular tube, and a front surface and a rear surface of the orifice plate are provided. A fluid pressure detecting device, wherein the hole and the pressure sensor are provided respectively. 3. The fluid pressure detecting device according to claim 1, wherein the hole according to claim 1 or 2 is arranged on the circular pipe at a position circumferentially separated by 45 ± 10 degrees. 4. A flow rate measuring device for measuring a flow rate of a fluid flowing in a circular pipe from a differential pressure between output pressures of pressure sensors on a front side and a rear side of the orifice plate of the fluid pressure detecting device according to claim 2. Method. 5. The fluid pressure measuring device according to claim 2, wherein an outer peripheral surface of the circular tube of the pressure sensor is vertically opposed to a flow direction of the fluid, and a total pressure is applied from a hole on the front side to the rear side. A flow velocity measuring method in which a static pressure is measured from a hole of the above and the flow velocity is measured from the difference.