JPH0510611B2 - - Google Patents
Info
- Publication number
- JPH0510611B2 JPH0510611B2 JP59044475A JP4447584A JPH0510611B2 JP H0510611 B2 JPH0510611 B2 JP H0510611B2 JP 59044475 A JP59044475 A JP 59044475A JP 4447584 A JP4447584 A JP 4447584A JP H0510611 B2 JPH0510611 B2 JP H0510611B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- receiving unit
- microwaves
- microwave
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
- G01N9/24—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by observing the transmission of wave or particle radiation through the material
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measuring Volume Flow (AREA)
Description
【発明の詳細な説明】
本発明は、マイクロ波を使用して、粉炭等の粉
体の流量をリアルタイムで計測する粉体流量計に
関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder flow meter that measures the flow rate of powder such as pulverized coal in real time using microwaves.
従来のマイクロ波を使用した粉体流量計は、第
１図に示すように、粉体を矢印Ａ方向に搬送する
金属製の搬送管１の途中に、所定距離Ｂだけ離し
てドツプラー送受信ユニツト２と受信ユニツト３
を導波管４，５を介して接続して構成している。 As shown in FIG. 1, a conventional powder flow meter using microwaves has a Doppler transmitting/receiving unit 2 placed in the middle of a metal conveying pipe 1 that conveys powder in the direction of arrow A, at a predetermined distance B. and receiving unit 3
are connected via waveguides 4 and 5.
この粉体流量計では、ドツプラー送受信ユニツ
ト２からマイクロ波を搬送管１内に入射し、その
搬送管１内を搬送されている粉体により反射され
てきた反射マイクロ波をドツプラー送受信ユニツ
ト２で受信して、その反射マイクロ波と入射マイ
クロ波とをミキサーにて混合することにより両マ
イクロ波の周波数差に応じた周波数のビート、即
ちドツプラー周波数を得て、これにより粉体の搬
送速度の情報を得ている。 In this powder flowmeter, a Doppler transmitting/receiving unit 2 injects microwaves into a conveying tube 1, and the Doppler transmitting/receiving unit 2 receives the reflected microwaves reflected by the powder being conveyed in the conveying tube 1. Then, by mixing the reflected microwave and the incident microwave in a mixer, a beat frequency corresponding to the frequency difference between the two microwaves, that is, a Doppler frequency, is obtained, and information on the conveyance speed of the powder can be obtained from this. It has gained.
また、ドツプラー送受信ユニツト２から搬送管
１内に入射されたマイクロ波の一部は、その搬送
管１に沿つて伝搬して、途中で粉体の密度に応じ
て振幅が減少（電力損失が発生する）し位相が変
化して、受信ユニツト３に到達するので、この受
信ユニツト３で得られるマイクロ波の位相或いは
電力と、ドツプラー送受信ユニツト２で送信され
たマイクロ波の位相或いは電力とを比較して、粉
体の密度情報を得ている。 In addition, some of the microwaves input from the Doppler transmitting/receiving unit 2 into the conveying tube 1 propagate along the conveying tube 1, and the amplitude decreases along the way depending on the density of the powder (power loss occurs). The microwave reaches the receiving unit 3 with a changed phase, so the phase or power of the microwave obtained at the receiving unit 3 is compared with the phase or power of the microwave transmitted by the Doppler transmitting/receiving unit 2. The density information of the powder is obtained.
そして、この密度情報と上記した搬送速度情報
とから、粉体の流量を計測している。 Then, the flow rate of the powder is measured from this density information and the above-mentioned conveyance speed information.
ところで、上記したマイクロ波の位相の変化或
いは電力の損失は、搬送されている粉体との相互
作用により生じるものであるが、搬送管１内のマ
イクロ波の電界分布は、その搬送管１が丸管の場
合には第２図（ａはTE11波）に示すように中心
軸の電界が一番強く周辺部に近づくほど弱くなつ
ており（搬送管１が矩形の場合でも同じ。）、また
粉体は搬送管１内に充満しているとは限らない。 By the way, the above-mentioned change in the phase of the microwave or loss of power is caused by the interaction with the powder being transported, but the electric field distribution of the microwave inside the transport tube 1 is caused by the fact that the transport pipe 1 In the case of a round tube, as shown in Figure 2 (a is TE 11 wave), the electric field at the central axis is strongest and becomes weaker as it approaches the periphery (the same applies even if the conveyor tube 1 is rectangular). Further, the conveying pipe 1 is not necessarily filled with powder.
従つて、同一密度の粉体であつても、その粉体
が搬送管１内の断面部分のどの位置にあるかによ
つて、得られる密度情報に差が生じ、その密度情
報に誤差が生じ、ひいては流量計測に誤差が生じ
る。 Therefore, even if the powder has the same density, there will be a difference in the density information obtained depending on the position of the powder in the cross section in the conveying pipe 1, and an error will occur in the density information. , which in turn causes an error in flow rate measurement.
また、第１図に示す構成の粉体流量計では、マ
イクロ波が必要な距離Ｂ内以外にも伝搬して受信
ユニツト３に到達しないものが生じるので、これ
も密度情報の誤差の原因となつている。 Furthermore, in the powder flowmeter with the configuration shown in Figure 1, some microwaves propagate beyond the required distance B and do not reach the receiving unit 3, which can also cause errors in density information. ing.
本発明は斯かる点に鑑みて成されたもので、そ
の目的は、マイクロ波電界の強弱やマイクロ波の
他への漏洩等によつて密度情報に誤差が発生せ
ず、よつて高精度な流量計測ができるようにした
粉体流量計を提供することである。 The present invention has been made in view of the above, and its purpose is to prevent errors in density information due to the strength of the microwave electric field or leakage of microwaves to other sources, and thus to provide highly accurate density information. An object of the present invention is to provide a powder flowmeter capable of measuring flow rate.
以下、本発明の実施例について説明する。第３
図はその一実施例を示すものであり、６はマイク
ロ波損失の少ない低損失誘導体で成る粉体搬送用
の断面が丸形の搬送管（低損失誘電体管）、７は
断面が矩形で全体形状がほぼコ字形状に曲折した
金属製の導波管であり、搬送管６はその軸心が導
波管７の中央部分７ａの軸心と同軸となるよう
に、その中央部分７ａを貫通している。そして、
導波管７の曲折した一方の端部（粉体の搬送され
てくる側）にドツプラー送受信ユニツト２が、ま
た他方の端部（粉体の搬送されて行く側）に受信
ユニツト３が各々取り付けられている。８，９は
搬送管６を導波管７内に固定貫通するための金属
製の丸形のガイド管である。 Examples of the present invention will be described below. Third
The figure shows one example of this, in which 6 is a conveyor tube (low-loss dielectric tube) with a round cross section for conveying powder made of a low-loss dielectric with little microwave loss, and 7 is a rectangular cross-section. It is a metal waveguide whose overall shape is approximately U-shaped. Penetrating. and,
A Doppler transmitting/receiving unit 2 is attached to one bent end of the waveguide 7 (the side from which the powder is conveyed), and a receiving unit 3 is attached to the other end (the side from which the powder is conveyed). It is being Reference numerals 8 and 9 designate round metal guide tubes for fixedly passing the carrier tube 6 through the waveguide 7.
以上において、導波管７におけるマイクロ波電
界の分布は、TE10波では第４図に示すように、
その中心部の電界が強く、長手方向の両側が一番
弱い。ところが、この実施例では搬送管６を、導
波管７の中央部７ａに同軸的に貫通させているの
で、その搬送管６は電界が強くその大きさがほぼ
同一の部分に位置することになる。従つて、搬送
管６内の粉体には、その搬送管６内における断面
方向の位置の如何に拘らず、ほぼ同一の電界が加
わる。 In the above, the distribution of the microwave electric field in the waveguide 7 is as shown in Fig. 4 for TE 10 waves.
The electric field is strong in the center and weakest on both sides of the length. However, in this embodiment, since the carrier tube 6 coaxially penetrates the central portion 7a of the waveguide 7, the carrier tube 6 is located in a portion where the electric field is strong and the magnitude is almost the same. Become. Therefore, substantially the same electric field is applied to the powder in the transport pipe 6 regardless of its position in the cross-sectional direction within the transport pipe 6.
一方、導波管にはその寸法に応じて、特定周波
数以下のマイクロ波は伝搬させないカツトオフ周
波数があり、例えば長辺がａの矩形の導波管で
は、そのカツトオフ周波数のときの波長、つまり
カツトオフ波長〓ｃは〓ｃ＝2aである。また、
半径がｒの丸形導波管では〓ｃ＝２〓ｒ／ｋ（ｋ
は使用する電磁界のモードによつて決まる定数。）
である。従つて、上記実施例では、使用マイクロ
波の周波数が予め決まつているときには、搬送管
６の外径を上記カツトオフ波長となる寸法に設定
することにより、或いは搬送管６の径が予め決ま
つているときは、その搬送管６の外径で決まるカ
ツトオフ波長以上の波長のマイクロ波を使用する
ことにより、その搬送管６におけるガイド管８，
９の取付部より外側の部分に対しては、マイクロ
波が漏洩することはなくなり、そこにおけるマイ
クロ波損失をが無くなる。 On the other hand, waveguides have a cutoff frequency that prevents microwaves below a certain frequency from propagating, depending on their dimensions.For example, in a rectangular waveguide with long sides a, the wavelength at that cutoff frequency, that is, the cutoff The wavelength 〓c is 〓c=2a. Also,
For a round waveguide with radius r, 〓c=2〓r/k(k
is a constant determined by the mode of the electromagnetic field used. )
It is. Therefore, in the above embodiment, when the frequency of the microwave to be used is predetermined, the outer diameter of the conveyor tube 6 is set to a dimension that corresponds to the cut-off wavelength, or the diameter of the conveyor tube 6 is determined in advance. When the guide tube 8 in the conveying tube 6 is
Microwaves no longer leak to the portion outside the mounting portion 9, and microwave loss therein is eliminated.
以上により、搬送管６内の粉体にはほぼ同一の
電界が加わり、またマイクロ波の外部への漏洩も
なくなるので、ドツプラー送受信ユニツト２から
受信ユニツト３に至るマイクロ波は、その位相や
電力が搬送管６内の粉体の密度によつて連続的に
変化する。なお、マイクロ波の位相や電力は導波
管７の曲折部分や搬送管６自体の影響もうける
が、これらは定数として扱うことができるので、
そこで得られる密度信号或いは最終的に得られる
流量信号を補正することにより、正確な流量を計
測することができる。 As a result of the above, almost the same electric field is applied to the powder in the conveying tube 6, and there is no leakage of microwaves to the outside, so that the microwaves reaching from the Doppler transmitter/receiver unit 2 to the receiver unit 3 have different phases and powers. It changes continuously depending on the density of the powder inside the transport tube 6. Note that the phase and power of the microwave are influenced by the bent portion of the waveguide 7 and the carrier tube 6 itself, but these can be treated as constants, so
By correcting the density signal obtained there or the flow rate signal finally obtained, an accurate flow rate can be measured.
第５図は別の実施例の構造を示すものであり、
導波管７′におけるドツプラー送受信ユニツト２
や受信ユニツト３に対する取り付け部分の曲折部
分がほぼ90度となつている以外は第３図に示した
ものと同一である。 FIG. 5 shows the structure of another embodiment,
Doppler transmitter/receiver unit 2 in waveguide 7'
It is the same as that shown in FIG. 3, except that the bent portion of the mounting portion for the receiving unit 3 is approximately 90 degrees.
なお、搬送管６はその少なくとも導波管７，
７′を貫通する部分が低損失誘導体で形成されて
いれば良く、他は通常の搬送管と同様の金属であ
つても良い。また、導波管７，７′は丸形であつ
ても良く、更に搬送管６は矩形であつても良い。 Note that the carrier pipe 6 has at least its waveguides 7,
It is sufficient that the portion passing through 7' is made of a low-loss dielectric, and the rest may be made of the same metal as a normal conveying pipe. Moreover, the waveguides 7, 7' may be round, and the conveying pipe 6 may be rectangular.
以上から本発明によれば、ドツプラー送受信ユ
ニツトから受信ユニツトに至るマイクロ波の漏洩
や不均一電界に基づく密度情報の誤差の発生を防
止することができ、精度の向上した流量計を実現
することができるという特徴がある。 As described above, according to the present invention, it is possible to prevent the leakage of microwaves from the Doppler transmitting/receiving unit to the receiving unit and the occurrence of errors in density information due to non-uniform electric fields, and it is possible to realize a flowmeter with improved accuracy. It has the characteristic that it can be done.
第１図は従来の流量計の構造を示す断面図、第
２図ａは従来の搬送管内の電界モードを示す図、
ｂはその電界の分布を示す特性図、第３図は本発
明の一実施例の流量計の構造を示す断面図、第４
図ａは第３図における導波管の中央部分の電界モ
ードを示す断面図、ｂはその電界の分布を示す特
性図、第５図は別の実施例の流量計の構造を示す
断面図である。
１……金属で成る搬送管、２……ドツプラー送
受信ユニツト、３……受信ユニツト、４，５……
導波管、６……搬送管（低損失誘電体管）、７，
７′……導波管、８，９……金属で成るガイド管。
Figure 1 is a sectional view showing the structure of a conventional flowmeter, Figure 2a is a diagram showing the electric field mode in a conventional conveying pipe,
b is a characteristic diagram showing the distribution of the electric field, FIG. 3 is a sectional view showing the structure of a flowmeter according to an embodiment of the present invention, and FIG.
Figure a is a cross-sectional view showing the electric field mode in the central part of the waveguide in Figure 3, b is a characteristic diagram showing the distribution of the electric field, and Figure 5 is a cross-sectional view showing the structure of a flowmeter according to another embodiment. be. 1... Conveyance tube made of metal, 2... Doppler transmitting/receiving unit, 3... Receiving unit, 4, 5...
Waveguide, 6...Carrier tube (low loss dielectric tube), 7,
7'... Waveguide, 8, 9... Guide tube made of metal.
Claims (1)
波を入射して、その入射マイクロ波と上記粉体で
反射した反射マイクロ波とから得られるドツプラ
ー周波数により上記粉体の流速信号を得ると共
に、上記入射マイクロ波の上記粉体による損失或
いは位相遅れにより上記粉体の密度信号を得、該
密度信号と上記流速信号とにより上記粉体の流量
を計測するようにした粉体流量計において、 上記搬送管の少なくとも一部を低損失誘電体管
にて形成し、ほぼコ字形状に曲折した金属製の導
波管の中央部分に上記低損失誘電体管を同軸とな
るように貫通させ、上記導波管の一端にドツプラ
ー送受信ユニツトを接続すると共に、他端に受信
ユニツトを接続し、且つ上記低損失誘電体管の径
で決まるカツトオフ周波数以下の周波数のマイク
ロ波を使用して成る粉体流量計。[Claims] 1. Microwaves are incident on the conveying direction of a conveying pipe that conveys powder, and the Doppler frequency obtained from the incident microwave and the reflected microwave reflected by the powder is used to control the concentration of the powder. In addition to obtaining a flow velocity signal, a density signal of the powder is obtained by loss or phase delay of the incident microwave due to the powder, and the flow rate of the powder is measured based on the density signal and the flow velocity signal. In the mass flow meter, at least a part of the conveying pipe is formed of a low-loss dielectric pipe, and the low-loss dielectric pipe is coaxially arranged in the center of a metal waveguide bent into a substantially U-shape. A Doppler transmitting/receiving unit is connected to one end of the waveguide, a receiving unit is connected to the other end, and microwaves having a frequency below the cutoff frequency determined by the diameter of the low loss dielectric tube are used. A powder flow meter made of
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59044475A JPS60187818A (en) | 1984-03-08 | 1984-03-08 | Flow meter for powdery body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59044475A JPS60187818A (en) | 1984-03-08 | 1984-03-08 | Flow meter for powdery body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60187818A JPS60187818A (en) | 1985-09-25 |
| JPH0510611B2 true JPH0510611B2 (en) | 1993-02-10 |
Family
ID=12692547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59044475A Granted JPS60187818A (en) | 1984-03-08 | 1984-03-08 | Flow meter for powdery body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60187818A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7610816B2 (en) | 2006-11-02 | 2009-11-03 | Ohm Electric Co., Ltd. | Flow measurement device |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011077782A1 (en) * | 2011-06-20 | 2012-12-20 | Robert Bosch Gmbh | Apparatus for dispensing powdery product e.g. coffee powder, has sensor that is connected to control unit for controlling metering device, based on detected density of powdered product |
| CN113324603A (en) * | 2021-04-16 | 2021-08-31 | 浙江纺织服装职业技术学院 | Detection apparatus for nonmetal pipe flow through state |
-
1984
- 1984-03-08 JP JP59044475A patent/JPS60187818A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7610816B2 (en) | 2006-11-02 | 2009-11-03 | Ohm Electric Co., Ltd. | Flow measurement device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60187818A (en) | 1985-09-25 |
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