JP2000146646A - Powder flow rate measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the powder flow rate measuring precision by measuring the bulk density of the powder and the phase change of a microwave to set relevant coefficients between both. SOLUTION: A measuring data processor system 15 fetches output signals from waveguides 11a-11c when no ash falls in a measuring unit 81 and a lower part 82 and measures with the phases of these signals set as reference phases. After this measurement, ash in an ash reservoir 6 is charged in the measuring unit 81, the processor system 15 fetches the output signal from the waveguide 11a, measures its phase, calculates the difference between this phase and the reference phase as a phase change due to the ash charging, calculates a proportional const. k of a specified equation to obtain the bulk density of the ash, based on the phase change, the inner vol. of the measuring unit 81 and the weight of the ash, then fetches output signals from the waveguides 11b, 11c with ash being carried on a discharge vehicle 9, and calculates the phase changes in the waveguides 11b, 11c, based on the phases of these signals. The processor system 15 processes these phase changes by the arithmetic technique using cross correlation functions, etc., and calculates the falling rate, the instantaneous flow rate and the cumulative flow rate of the ash, based on specified equations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder flow rate measuring device for measuring the flow rate of powder such as coal ash using microwaves.

[0002]

2. Description of the Related Art In a plant for burning coal fuel, coal ash produced by the combustion is discharged to the outside through an ash discharge facility as shown in FIG. In FIG. 20, coal ash generated in the coal-fired boiler 1 and the like flows through the flue 2 together with the exhaust gas. The flue gas is released into the atmosphere from a gas discharge facility 3 such as a chimney provided at the end of the flue 2, and the coal ash is discharged into the middle of the flue 2
P (electro-statistics precipi
After being collected by an ash collection facility 4 such as an ash storage device, the ash is passed through an ash transport path 5 and stored in an ash storage tank 6. The coal ash stored in the ash storage tank 6 is discharged to the unloading vehicle 9 through the on-off valve 7 and the ash flow path 8.
The discharge amount is measured by the powder flow rate measuring device 10 shown in FIG.

[0003] The powder flow rate measuring device 10 comprises a pair of upper and lower waveguides 11 b and 11 c which are disposed in such a manner that the ash flow path 8 penetrates the central portion, and these waveguides via a coaxial cable 12. A microwave transmitter 13 for supplying a microwave to one end of each of the waveguides 11b and 11c, and a measurement data processing system 15 connected to the other ends of the waveguides 11b and 11c via a coaxial cable 14 are provided.

The operation of the conventional powder measuring device 10 will be described below. Since the wall of the ash flow path 8 at the position where the waveguides 11 and 12 are disposed is formed of a microwave transmitting material 16 such as Teflon, the waveguide 11 b is transmitted from the microwave transmitter 13 through the coaxial cable 12. , 11c pass through the microwave transmitting material 16 and interact with the ash in the ash flow path 8. Therefore, the measurement data processing system 15 first sets the waveguide 11 in a state where the on-off valve 7 is closed, that is, in a state where ash does not flow down the ash flow path 8.
b, and 11c output signal of the phase φ _b0, φ _c0 reference phase (0
Phase), and then with the on-off valve 7 open,
That is, the phases φ _{b1 (t)} and φ _{c1 (t)} of the output signals of the waveguides 11b and 11c while the ash flows down in the ash flow path 8 are measured. And, based on these measured phases,
Phase change Δφ _{b (t)} = φ _{b1 (t)} −φ _b0 , Δφ _{c (t)} = φ
_{c1 (t)} as well as calculating the -.phi _c0, it is a function of time these phase variation Δφ _{b (t),} the cross-correlation function and the waveguide 11b, based on the arrangement interval of 11c of Δφ _{c (t)} Then, the falling speed v of the ash in the ash flow path 8 is calculated.

The amount of phase change experimentally obtained by using the waveguide 11c is Δφ _c ′, the weight bulk density of ash (average value of ash) in the signal measurement area is ω, and the relation coefficient between them is k _0. Then
These have the following relationships. _{ω = k 0 · Δφ c '} ····· (A) Accordingly, the coefficient k ₀ obtained based on the formula (A)
And the instantaneous flow rate q (t) shown in the following equation (B) based on the ash falling velocity v and the sectional area S of the ash flow path 8, and based on the instantaneous flow rate q (t), An integrated flow rate Q _(T) shown in the following equation (C) is calculated. q (t) = S · v · k ₀ · φ _{c1 (t)} (B)

[0006]

(Equation 1)

[0007]

The above-mentioned conventional powder flow rate measuring apparatus has the following problems. a. When the powder to be measured is coal ash, the electrical characteristics of the unburned carbon remaining without burning are significantly larger than those of the other ash components. Depends greatly on the unburned carbon content.
However, in the above conventional powder flow rate measuring device,
As shown in the equation (A), the phase change amount Δ experimentally measured for ash containing a certain amount of residual unburned carbon content.
Since the coefficient k ₀ is calculated based on φ _c ′ and the general bulk density of coal ash, the actual residual unburned carbon content of the measurement target ash is not reflected in this coefficient k ₀ , Therefore, there arises a problem that the instantaneous flow q (t) as well as the accuracy of the integrated flow rate Q _m is very low. b. In the above-mentioned conventional powder flow rate measuring device, the distance from the microwave transmitter 13 to the waveguides 11b and 11c and the distance from the waveguides 11b and 11c to the measurement data processing system 15 are long. They are connected by a cable 12 and the latter are connected by a coaxial cable 14. However, the coaxial cables 12, 14
The dielectric constant of the internal dielectric changes with the temperature change of the surrounding environment. This change in the dielectric constant changes the group velocity of microwaves in the coaxial cables 12 and 14. Therefore, the conventional powder flow rate measuring device 10 has a problem that an error occurs in the phase measurement value due to a temperature change in the surrounding environment of the coaxial cable 12. An object of the present invention is to provide a powder flow measuring device capable of improving the measurement accuracy by removing the above-described factors of the decrease in the measurement accuracy in view of the problems of the conventional device.

[0008]

According to a first aspect of the present invention, a relational coefficient between a phase change amount of a microwave and a powder bulk density when a microwave is applied to the powder is set in advance, and the relation coefficient is determined. In a powder flow rate measuring device that measures a flow rate of the powder based on a coefficient, a flow rate of the powder, a cross-sectional area of a flow path of the powder, and a phase change amount of the microwave, the powder to be measured is And a relation coefficient setting means for setting the relation coefficient by actually measuring the weight and bulk density of the powder and the phase change amount of the microwave applied to the powder. In a second aspect based on the first aspect, the relation coefficient setting means is arranged so that the powder flow path is provided on a first on-off valve and a downstream side of the first on-off valve.
And a first waveguide means for applying microwaves to the powder filled in the calibration section, and measuring the weight of the powder filled in the calibration section. And a weight measuring unit configured to set the relation coefficient based on the amount of phase change of the microwave in the first waveguide unit, the weight of the powder, and the volume of the calibration unit. A third invention is a method according to the first or second invention, wherein
A water addition means for adding a predetermined percentage of water to the powder is provided. In a fourth aspect based on any one of the first to third aspects, a microwave is applied to a portion of the flow path of the powder downstream of the calibration section, the microwave being applied to the powder flowing through the portion. 2. The third and third waveguides are arranged at a predetermined interval, and the flow speed of the powder is measured based on the correlation between the phase change amounts of the microwaves in the second and third waveguides. Like that. In a fifth aspect based on the second or third aspect, the second aspect is provided.
The on-off valve has a structure in which no protrusion is interposed in the internal flow path, and a second waveguide means for applying a microwave to the powder flowing through the portion at a portion downstream of the calibration portion. Is arranged, and the flow speed of the powder is measured based on the correlation between the phase change amounts of the microwaves in the first and second waveguide means. In a sixth aspect based on the second or third aspect, the flow rate of the powder is determined using only the phase change amount of the microwave in the first waveguide means under the condition that the flow speed of the powder is constant. Is measured. In a seventh aspect based on any one of the first to sixth aspects, the microwave transmission system connected to the waveguide means comprises: frequency conversion means for increasing the frequency of the input microwave; It is characterized by comprising a coaxial cable for transmitting the raised microwave, and frequency conversion means for lowering the frequency of the microwave transmitted by the coaxial cable to the frequency of the input microwave. In an eighth aspect based on any one of the first to sixth aspects, the microwave transmission system connected to the waveguide means reduces the frequency of the input microwave to a frequency that can be converted into an optical signal. Frequency converting means, electro-optical converting means for converting an output of the frequency converting means into an optical signal, an optical fiber for transmitting the optical signal, and a light for converting the optical signal transmitted by the optical fiber into an electric signal. -It is characterized by comprising electric conversion means and frequency conversion means for increasing the frequency of the converted electric signal to the frequency of the inputted microwave. According to a ninth invention, in any one of the first to sixth inventions, a waveguide is used for a microwave transmission system connected to the waveguide means. According to a tenth aspect, in any one of the first to sixth aspects, the microwave transmission system connected to the waveguide means distributes the input microwave into two parts, and the distribution means distributes the inputted microwave into two parts. A first coaxial cable for transmitting one of the selected microwaves and supplying the microwave to the waveguide means, and transmitting a microwave output from the waveguide means, and having the same characteristics as the first coaxial cable. And a second coaxial cable having a length and transmitting the other microwave distributed by the distribution means, and a first and second microwave output from the first and second coaxial cables, respectively. A phase detection unit that detects a phase of the wave signal; and a phase comparison unit that obtains a phase of the first microwave signal with reference to a phase of the second microwave signal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a powder flow measuring device according to the present invention will be described below with reference to the drawings. In the drawings used in the following description, the same reference numerals are given to the same or common components as those of the conventional device shown in FIG.

(First Embodiment) As shown in FIG. 1, in a powder flow measuring device 100-1 according to a first embodiment,
A lower opening / closing valve 7b is interposed in the middle of an ash flow path 80 connected to the lower end of the ash storage tank 6, and a calibration section 81 is configured between the opening / closing valve 7b and the upper opening / closing valve 7a. . Calibration unit 81
Penetrates through the central portion of the waveguide 11a.
Lower part 82 penetrates through the central part of the waveguides 11b and 11c. In the ash flow path 80, the wall portions corresponding to the locations where the waveguides 11a, 11b, and 11c are arranged are each formed of the microwave transmitting material 16. The calibration section 81 and the lower section 82 of the ash flow path 80 are provided with expandable expanders 81a and 82a at the upper ends, respectively. Therefore, the calibration section 81 can move up and down within a predetermined range.

Below the waveguide 11a, the calibration section 81 is provided.
Weight measuring device 19 for measuring the weight of ash 18 filled in the inside
Is arranged. Note that, for example, a load cell is used as the weight measuring device 19. The microwave transmitter 13 and one end of each of the waveguides 11a, 11b and 11c, and the other end of each of the waveguides 11a, 11b and 11c and the measurement data processing system 15 are connected by a transmission system 20, which will be described later. .

The operation of the powder flow measuring device 100-1 according to this embodiment will be described below. Microwave transmitter 13
From the waveguides 11a, 11b and 1
When a microwave is supplied to 1c, the microwave is transmitted through the microwave transmitting material 16 and transmitted into the ash flow path 8. The measurement data processing system 15 includes the calibration unit 8 of the ash flow path 80.
The output signals of the respective waveguides 11a to 11c when the ash is not flowing down in 1 and the lower portion 82 are taken in, and the phases φ _{a0 to} φ _c0 of these signals are measured as reference phases (zero phase). After measuring the reference phase φ _{a0 to} φ _c0 , open / close valve 7
The ash in the ash storage tank 6 is filled in the calibration section 81 by opening and closing operations of the a and the b. Therefore, the measurement data processing system 15
Captures the output signal of the waveguide 11a and outputs its phase φ _a1
And the difference Δφ between this phase φ _a1 and the reference phase φ _a0
The _a = _{φ a1 -φ a0} is calculated as a phase change amount due to ash filling. Then, the phase change amount Δφ _a and the weight
Based on the weight w of the ash in the calibration unit 81 measured by the above and the internal volume V of the calibration unit 81 measured in advance, a proportional constant k shown in the following equation (1) is calculated. k = (w / V) / Δφ _a (1) Note that w / V in the above equation (1) indicates the weight bulk density of the ash.

Next, both the on-off valves 7a and 7b are opened, whereby the ash in the ash storage tank 6 is removed from the weighing section 8 of the ash flow path 80.
1 and a carry-out vehicle 9 such as a truck flowing down the lower portion 82
To be loaded. Therefore, the measurement data processing system 15 takes in the output signals of the waveguides 11b and 11c and measures the phases φ _b1 and φ _c1 of those signals, respectively. Then, calculates a difference Δφ _b = φ _b1 -φ _b0 and said the phase phi _b1 reference phase phi _b0 as phase variation in the waveguide 11b, and the difference between the a phase phi _c1 reference phase phi _c0 [Delta] [phi _c = φ _c1 −φ _c0 is calculated as the amount of phase change in the waveguide 11c.

FIG. 2 shows the phase change Δ with time.
It is a waveform diagram which illustrated the change aspect of (phi) _b and (DELTA ₎ (phi) _c . Since the delay time τ shown in FIG. 2 corresponds to the time required for the falling ash to be measured to move between the waveguides 11b and 11c, in the measurement data processing system 15,
The phase change amounts Δφ _b and Δφ _c are processed by an arithmetic method using a cross-correlation function or the like to calculate the delay time τ. Now, assuming that the arrangement interval between the middle and lower waveguides 11b and 11c is L, the falling speed v of the ash is given by: v = L / τ (2) Then, the sectional area of the main ash flow path 8 is represented by S,
The phase signal of the lower waveguide 11c at time t is Δφ
Assuming that _{c (t)} , the instantaneous ash flow rate q discharged from the lower end of the ash flow path 8 at this time t is given by: q = kvSΔφc _(t) (3) Therefore, the integrated flow rate Q of the ash from the time t = 0 when the ash flow starts to the time t = T is expressed by the following equation (4).

[0015]

(Equation 2)

Therefore, the measurement data processing system 15 calculates the ash falling velocity v, the instantaneous ash flow rate q, and the integrated flow rate Q based on the above equations (2), (3) and (4). By the way, the powder flow measuring device 100 according to the first embodiment is described.
According to -1, extremely high flow rate measurement accuracy can be obtained. That is, the the powder flow rate measuring apparatus 100-1, are measured by using the calibration unit 81 of the (1) Hairyuro 8 weight bulk density w / V and the phase change amount [Delta] [phi _a of ash in formula Therefore, the relation coefficient k for them is set according to the amount of unburned carbon actually remaining in the ash to be measured,
As a result, the instantaneous ash flow rate q and the integrated flow rate Q are measured with high accuracy. FIG. 3 shows the measuring device 100 of the embodiment.
Integrated flow rate Q (weight of falling ash) measured by -1;
It is the graph which showed the relationship with the loading ash weight actually measured by the truck scale after loading. As shown in FIG. 3, the difference between the measurement result of the measuring device 100-1 and the actually measured load weight is extremely small.
This suggests that the measurement accuracy of No. 1 is high. The work of loading ash onto the unloading vehicle 9 was completed when the integrated flow rate Q reached the target weight (8 tons).

FIG. 4 shows the ash loading weight in the loading vehicle 9 (in this example, a truck having an allowable loading capacity of 8 tons) in a plurality of loading operations using the powder flow rate measuring device 100-1. The result of the case is shown. As shown in FIG. 4, by using the flow rate measuring device 100-1, the loading amount of ash in the unloading vehicle 9 is controlled to an appropriate amount (weight close to 8 tons) not exceeding the target loading amount of 8 tons. Can be.

(Second Embodiment) As shown in FIG. 5, a powder flow measuring device 100-2 according to a second embodiment is different from the powder flow measuring device 100-1 shown in FIG. Part 30
And a configuration in which an added water amount control unit 40 is added. The water addition section 30 includes a water pipe 31 connected to a lower end of the ash flow path 80, and an electromagnetic flow control valve 32 and a flow meter 33 interposed in the middle of the water pipe 31. The added water amount control unit 40 takes in the instantaneous ash flow rate q calculated based on the equation (3) from the measurement data processing system 15 via the signal line 51, and multiplies the instantaneous ash flow rate q by a predetermined fraction. To set the target amount of added water. Then, the opening of the flow control valve 32 is controlled via the signal line 52 so that the target amount of water is added to the ash. Specifically, the opening of the electromagnetic flow regulating valve 32 is controlled such that the deviation between the target added water amount and the actual added water amount input from the flow meter 33 via the signal line 53 becomes zero.

The fraction by which the instantaneous ash flow rate q is multiplied defines the amount of moisture that can prevent the ash from rising when the ash is loaded into the carry-out vehicle 9, in other words, the amount of moisture that gives the ash wetness that does not cement. The value is set so that water: ash = 15: 85 to 25:75. In this embodiment, the above fraction is set to 20.
Since / 80 is set, the ratio of the moisture and ash of the wet ash is adjusted to 20:80 by the control of the added water. Powder flow measuring device 100- according to this embodiment
Reference numeral 2 has both the flow rate measuring function of the powder flow rate measuring device 100-1 in FIG. 1 and the water addition function. Therefore, the wet ash can be discharged to the carry-out vehicle 9 while accurately measuring the ash flow rate.

FIG. 6 shows the powder flow rate measuring device 100-2.
4 is a graph showing the relationship between the wet ash falling weight measured by the method and the loaded wet ash weight actually measured on a truck scale after loading. As shown in this graph, this measuring device 10
The difference between the ash weight measured by 0-2 and the actually measured load weight is extremely small,
This suggests that the flow measurement accuracy of No. 1 is extremely high.

Table 1 below shows the results of analysis of the fractions of ash and moisture in the wet ash loaded on the unloading vehicle 9 by each loading operation. It is confirmed that they are mixed at a ratio almost close to the weight fraction (80:20) to be used.

[0022]

[Table 1]

On the other hand, FIG. 7 shows an unloading vehicle 9 (in this example,
The results obtained when a plurality of times (#a to #e) are performed while managing the loading weight of the wet ash with respect to the truck having an allowable loading capacity of 8 tons) based on the flow rate measurement result of the powder flow rate measuring device 100-2. Is shown. As shown in FIG. 7, if the flow rate measuring device 100-2 is used, an appropriate amount (a weight close to 8 tons) of wet ash that does not exceed the target loading amount of 8 tons in any loading operation is carried out by the vehicle 9. Can be loaded on Table 2 below shows the results of analysis of the fractions of ash and moisture in about 8 tons of each wet ash loaded by the loading operations #a to #e shown in FIG. As is clear from Table 2, each wet ash has its ash content and moisture mixed at a ratio almost close to the target weight fraction (80:20).

[0024]

[Table 2]

(Third Embodiment) FIG. 8 shows a third embodiment of the present invention.
Is shown. The powder flow measuring device 100-3 according to this embodiment includes a lower waveguide 11c shown in FIG.
The configuration is different from that of the device 100-1 shown in FIG. 1 in that the configuration is different from that in FIG. 1 in that a lower opening / closing valve 7b 'has a structure in which no protrusion is interposed in the internal flow path. The flow rate measuring function of the powder flow rate measuring device 100-3 of this embodiment is basically the same as that of the powder flow rate measuring device 100-1 shown in FIG. However, the powder flow rate measuring device 100-3
As described above, since the waveguide 11c shown in FIG. 1 is omitted as described above, the falling velocity v of the ash shown in the above equation (2) is calculated by the phase change amount Δ measured by the waveguides 11a and 11b.
phi _a, is calculated based on [Delta] [phi _b. And the above (3)
The instantaneous flow rate q of ash is calculated using the following equation (3) ′ according to the equation, and the integrated flow rate Q is calculated using the following equation (4) ′ according to the above equation (4). q = k · v · S · Δφ _{b (t)} (3) ′

[0026]

(Equation 3)

By the way, in the powder flow measuring device 100-1 shown in FIG. 1, as described above, the waveguides 11b, 11b
phase change amounts Δφ _b , Δφ detected by c
The time lag amount of the signal waveform _c (see FIG. 2) is obtained as the delay time τ, and the ash flow velocity v is calculated based on the delay time τ. The delay time τ can be recognized only on the assumption that the signal waveforms of the phase change amounts Δφ _b and Δφ _c are similar to each other. This is because if the two waveforms have different shapes, the correlation between the two waveforms becomes uncertain and it becomes difficult to recognize the delay time τ.

The approximation of the signal waveforms of the phase change amounts Δφ _b and Δφ _c means that there is no turbulence in the ash flow between the waveguides 11b and 11c, in other words, the flow direction of the falling ash flow. The sparse / dense pattern is the waveguide 11b and the waveguide 11
and c is maintained. In the embodiment shown in FIG. 1, the waveguide 11b,
Since there is no object disturbing the ash flow between 11c,
The delay time τ can be recognized based on the correlation between the two waveforms.

On the other hand, in the device 100-3 of the present embodiment in which the waveguide 11c is omitted, the waveguides 11a and 11
b, the phase change amounts Δφ _a and Δφ _b respectively detected by
The above delay time τ is calculated based on the time-varying waveform of the above, but a lower open / close valve 7b ′ is interposed between these waveguides 11a and 11b. Therefore, if the flow of the falling ash is disturbed by the opening / closing valve 7b ', the pattern of the falling ash in the flowing direction is changed to the waveguide 11b.
Therefore, it is difficult to calculate the delay time τ by utilizing the correlation of the time change waveforms of the phase change amounts Δφ _a and Δφ _b . Therefore,
In the present embodiment, as described above, the lower opening / closing valve 7b 'has a structure in which no protrusion is interposed in the internal flow path, that is, a structure which does not disturb the flow of the falling ash. , The delay time τ can be calculated.

Hereinafter, the structure of the conventional on-off valve 7b used in the embodiment of FIG. 1 and the structure of the on-off valve 7b used in this embodiment will be described. As shown in FIG. 9, the conventional on-off valve 7 b has a structure in which the outlet 72 is not positioned on the axis of the inlet 71, that is, a housing 73 in which the internal flow path is not straight, Valve seat 74,
A swingable valve member 75 is provided for separating and coming into contact with the valve seat 73 to open and close the internal flow path. As shown in FIG. 9B, which shows the open state of the on-off valve 7b, the flow direction of the ash is forcibly changed by the internal flow path.
Since the valve seat 74 interferes with a part of the ash, the turbulence of the ash flow in the inside is inevitable.

On the other hand, an on-off valve 7b 'shown in FIG. 10 has an inlet 77 and an outlet 78 coaxially formed at the upper and lower portions of a housing 76, and a central portion of the housing 76 interposed between the inlet 77 and the outlet 78. Valve member 79
Is provided. The valve member 79 slides on a spherical valve seat 76 a provided on the housing 76, and also has a shaft 79 a orthogonal to the axis of the inlet 77 and the outlet 78.
It is rotatably supported by. The valve member 79 has a valve hole 79 having the same diameter as the inlet 77 and the outlet 78.
b is formed so as to penetrate the shaft 79a at right angles.
According to the on-off valve 7b ', the inlet 77 and the outlet 78 are shut off (closed state) in the state shown in FIG. 10A in which the valve hole 79b is directed sideways, and the valve member 79 is opened from this state. 9
In the state shown in FIG. 10B in which the valve hole 79a is turned vertically by turning by 0 °, communication is established between the inlet 77 and the outlet 78 (open state). In the open state, a uniform linear internal flow path from the inlet 77 to the outlet 78 is formed,
The ash flowing from the inlet 77 is discharged from the outlet 78 without disturbing the flow.

Therefore, according to the embodiment of FIG. 8 using the on-off valve 7b ', the on-off valve 7c'
Despite being interposed between the waveguides 11a and 11b, the sparse and dense pattern in the ash flow direction changes from the waveguide 11a to the waveguide 11a.
b, and as a result, the phase change amounts Δφ _a , Δ
it is possible to accurately calculate the delay time τ on the basis of the correlation of phi _b of the waveform. In addition, as shown in FIG.
The valve hole 79a of the valve member 79 may be formed in a square cross section. In this case, the side length of the valve hole 79a is desirably set to the diameter of the inlet 77 and the outlet 78 or a length close thereto. . The powder flow measuring device 100-3 of the above embodiment is the same as the powder flow measuring device 100-
1 has the same function as the powder flow rate measuring apparatus 100-1 in FIG. Therefore, it is advantageous in reducing the size and cost.

(Fourth Embodiment) As shown in FIG. 12, a powder flow measuring device 100-4 according to a fourth embodiment is shown.
Has a configuration in which the water addition unit 30 and the added water amount control unit 40 shown in FIG. 5 are added to the powder flow rate measurement device 100-3 shown in FIG. Therefore, this powder flow measuring device 1
No. 00-4 is an effect of the powder flow rate measuring device 100-2 shown in FIG. 5 capable of discharging wet ash, and a powder size shown in FIG. 8 which can reduce the size and cost. It also has the effect of the flow measurement device 100-3.

(Fifth Embodiment) As shown in FIG.
The powder flow measuring device 100-5 according to the fifth embodiment includes:
It has a configuration in which the waveguide 11b shown in FIG. 8 is omitted. Now, assuming that the falling speed of the ash falling from the on-off valve 7a shown in FIG. 13 is constant, there is no need to calculate the above formula (2) for calculating the falling speed. This means that it is not necessary to calculate the delay time τ using the pair of waveguides 11a and 11b shown in FIG. 8, that is, it is not necessary to provide the waveguide 11b. Means
In this embodiment, based on such consideration, the waveguide 11b is omitted in consideration of use under the condition that the falling speed of the ash falling from the on-off valve 7a is constant. In the present embodiment having a single waveguide 11a, a falling speed v of the ash obtained experimentally in advance, and the phase change amount [Delta] [phi _a obtained based on the output signal of the waveguide 11a, The instantaneous ash flow rate q is calculated based on the following equation (3) ″ according to the above equation (3). Q = k · v · S · Δφ _{a (t)} (3) ” The instantaneous ash flow rate q is calculated based on the following equation (4) ″ according to the above equation (4).

[0035]

(Equation 4)

According to the powder flow rate measuring device 100-5 according to the fifth embodiment, the powder flow rate measuring device 100 shown in FIG. 8 has a simple configuration using only a single waveguide 11a. Since a function equivalent to -3 is obtained, significant cost reduction and size reduction can be achieved.

(Sixth Embodiment) As shown in FIG. 14, a powder flow measuring device 100-6 according to a sixth embodiment is shown.
Has a configuration in which the water adding unit 30 and the added water amount control unit 40 shown in FIGS. 5 and 12 are added to the powder flow rate measuring device 100-5 shown in FIG. Therefore, according to the powder flow rate measuring device 100-6, both the effect that the cost can be significantly reduced and the size can be reduced, and the effect that the wet ash can be discharged can be obtained.

Next, the devices 100-1 to 100-1 of the above embodiment are described.
The microwave transmission system 20 used in 00-6 will be described. The transmission system 20 shown in FIG. 15 includes an up-conversion mixer 201 connected to the output of the microwave oscillator 13 and an up-conversion mixer 201.
High-pass filter 202 for filtering the output signal of the above, a down-conversion mixer 204 connected to the high-pass filter 202 via a coaxial cable 203, a low-pass filter 205 for filtering the output signal of the down-conversion mixer 204, and an up-conversion mixer 201 And a high-frequency oscillator 207 for applying a sine-wave signal to the down-converter mixer 204. The down-converter mixer 204 is connected to the waveguide 11 (11a, 11b, 11b).
c). In addition, the high-frequency transmitter 20
6,207 output frequencies are equal to each other.

In the power supply system 20, the up-converting mixer 201 converts the microwave signal of frequency f 1 output from the microwave transmitter 13 and the sine wave signal of frequency f 2 output from the high-frequency transmitter 206. The signal components having the frequency of the absolute value of the sum of the frequencies of the two signals and the signal component having the frequency of the absolute value of the difference are output.

The signal component having the frequency of the absolute value of the difference is removed by the high-pass filter 202. Therefore, only the microwave signal having the frequency of the absolute value of the sum is input to the coaxial cable 203. The high-frequency microwave signal is transmitted to the vicinity of the waveguide 11 through the coaxial cable 203 and then input to the down-converter mixer 204. The down-conversion mixer 204 receives the input microwave signal and the frequency
7, the signal component having the frequency of the absolute value of the sum of the frequencies of the two signals and the frequency of the absolute value of the difference (the microwave oscillator 13)
(Equivalent to the output frequency f1). Of the signal components output from the down-conversion mixer 204, the signal component having the frequency of the absolute value of the sum is removed by the low-pass filter 205.
Is output. And this frequency f
The one microwave signal is input to the phase measurement waveguide 11 of the powder flow rate measuring devices 100-1 to 100-6 according to the above embodiments for phase measurement.

According to the transmission system 20, after the output of the microwave oscillator 13 is raised in frequency by the up-conversion mixer 201, the waveguide 1
1 will be transmitted. Coaxial cable 20
In No. 3, although the dielectric constant of the internal dielectric depends on the temperature of the surrounding environment, the temperature dependency decreases as the frequency of the energized signal increases. That is, for example, the temperature dependence of the relative dielectric constant when polychlorotrifluoroethylene is used as the material of the dielectric shows a tendency as illustrated in FIG. Therefore, if the transmission system 20 is employed, the change in the permittivity of the coaxial cable 203 due to the environmental temperature can be reduced, and the phase change of the microwave in the cable 203 can be suppressed. The accuracy of microwave phase measurement in the tube 11 is improved.

In the transmission system 20, two high-frequency oscillators 206 and 207 are provided. The output of one of the high-frequency oscillators is shared by the up-conversion mixer 201 and the down-conversion mixer 204. Such a configuration is also possible. The transmission system 20 includes:
It is also used between the waveguide 11 and the measurement data processing system 15. In this case, the output signal of the waveguide 11 is input to the up-conversion mixer 201, and the output signal of the low-pass filter 205 is used for measurement data processing. System 15
Is input to

FIG. 17 shows another example of the configuration of the transmission system 20. The power supply system 20 includes a down-converter mixer 208 connected to the output of the microwave oscillator 13, a low-pass filter 209 for filtering an output signal of the down-converter 208, and an electric power connected to an output of the low-pass filter 209. An optical changer 210, which converts an optical signal output from the electro-optical changer 210 into an optical fiber 211;
, An up-converting mixer 213 connected to the output of the optical-electrical converter 212, a high-pass filter 214 connected to the output of the up-converting mixer 213, and a down-converter A high-frequency oscillator 215 for applying a sine wave signal to the mixer 208 and a high-frequency oscillator 216 for applying a sine wave signal to the up-conversion mixer 213 are provided. In addition,
The optical-electrical converter 212 is arranged near the waveguide 11. In addition, high-frequency oscillators 215 and 21
6 generates a sine wave signal of the same frequency.

In the transmission system 20, the down-converting mixer 208 multiplies the microwave signal of the frequency f1 output from the microwave oscillator 13 by the sine wave signal of the frequency f3 output from the frequency oscillator 206. Thus, a signal having the frequency of the absolute value of the sum of the frequencies of both signals and a signal having the frequency of the absolute value of the difference are output.

Of the signal components output from the down-conversion mixer 201, the signal component having the frequency of the absolute value of the sum is removed by the low-pass filter 209. Therefore, the electro-optical converter 210 inputs a signal having a frequency of the absolute value of the difference, that is, a low-frequency signal that can be converted into an optical signal, and converts this signal into an optical signal. The optical signal is transmitted to the waveguide 1 by the optical fiber 211.
1 is transmitted to the vicinity. And the optical-electrical converter 21
After being converted into an electric signal again in step 2, the signal is input to the up-conversion mixer 213.

The up-conversion mixer 213 has a light-
The output signal of the electric converter 212 is multiplied by the sine wave signal of the frequency f3 output from the high-frequency transmitter 216, and the frequency of the absolute value of the sum of the frequencies of both signals (the output frequency f1 of the microwave transmitter 13) And a signal component having a frequency of the absolute value of the difference. Among the signal components output from the up-conversion mixer 213, the signal component having the frequency of the absolute value of the difference is removed by the high-pass filter 214, so that the original frequency f1 is output from the high-pass filter 214.
Is output. The microwave signal of the frequency f1 is input to the phase measurement waveguide 11 for phase measurement.

Since the optical signal transmitted by the optical fiber 211 is hardly affected by the environmental temperature, the transmission system 20
Is used, microwaves can be transmitted without a phase change due to environmental temperature. That is, if the transmission system 20 is interposed between the microwave transmitter 13 and the waveguide 11 as described above, the microwave having no phase change is supplied to the waveguide 11. If the transmission system 20 is interposed between the waveguide 11 and the measurement data processing system 15, the output signal of the waveguide 11 is guided to the measurement data processing system 15 without a phase change. Therefore, the transmission system 2
If the microwave is transmitted with 0, the phase change of the microwave in the waveguide 11 can be measured with extremely high accuracy. In the transmission system 20, two high-frequency oscillators 215 and 216 are provided. The output of one of the high-frequency oscillators is shared by the down-converting mixer 208 and the up-converting mixer 213. It is also possible.

FIG. 18 shows an example in which the transmission system 20 is constituted by a waveguide 217 having a predetermined length. Since the transmission phase of the microwave in the waveguide 217 depends on the tube shape, it is not affected by the temperature change. Therefore, as shown in the figure, if this transmission system 20 is interposed between the microwave oscillator 13 and the phase measuring waveguide 11, microwaves having no phase change can be supplied to the waveguide 11. In addition, this transmission system 2
If 0 is interposed between the waveguide 11 and the measurement data processing system 15, the output signal of the waveguide 11 can be guided to the measurement data processing system 15 without a phase change. Therefore, if the transmission system 20 is used, it is possible to accurately measure the phase change of the microwave in the waveguide 11.

FIG. 19 shows a transmission system from the microwave transmitter 13 to the measurement data processing system 15 via the waveguide 11.
That is, a transmission system 20 'which also serves as a transmission system 20 between the microwave transmitter 13 and the waveguide 11 and a transmission system 20 between the waveguide 11 and the measurement data processing system 15 in FIG. The transmission system 20 ′ includes a power divider 221 disposed near the microwave transmitter 13 and phase detectors 222 and 223 disposed near the measurement data processing system 15.
And one of the divided outputs of the power divider 221 and the waveguide 1
1 and the output end of the waveguide 11 and the phase detector 2
22, a coaxial cable 225 interposed between the other divided output of the power divider 221 and the phase detection 223, and phase detectors 222 and 22.
3 and a phase comparator 226 connected to each output. The coaxial cable 225 has the same characteristics and length as the coaxial cable 224. Further, the phase comparator 226 is provided near the measurement data processing system 15.

In the transmission system 20 ′, the power divider 221 splits the output of the microwave transmitter 13 into two. One distributed output is applied to one end of the waveguide 11 via a portion 224 a of the coaxial cable 224, and the other distributed output is applied to the phase detector 223 via the coaxial cable 225. The output signal of the waveguide 11 is
The coaxial cable 224 is applied to the phase detector 222 via another portion 224b. Therefore, one phase detection 2
The microwave whose phase has changed in the waveguide 11 and the coaxial cable 224 is input to the waveguide 22, and the microwave whose phase has changed in the coaxial cable 225 is input to the other phase detector 223. Become. The phase detectors 222 and 223 detect the phases of the input signals, respectively. Further, the phase detector 226 is a phase detector 2
The detected phase of the phase detector 22 is compared with the detected phase of the phase detector 223 to extract the latter phase based on the former phase.

The phase of the microwave passing through the coaxial cables 224 and 225 changes due to the change in the environmental temperature.
As described above, since the cables 224 and 225 are the same length and have the same electrical characteristics, the amounts of phase change of microwaves in these cables 224 and 225 are equal. Therefore, in the phase comparator 226,
The phase in which each phase change in the coaxial cables 224 and 225 is canceled, that is, the phase of the microwave whose phase has been changed only in the waveguide 11 is extracted.

The measurement data processing system 15 controls the waveguide 1 based on the phase extracted by the phase comparator 226.
Since the amount of phase change at 1 is measured, there is no possibility that the measurement result includes a phase change of the microwave in the coaxial cable 224 as an error. Therefore, this transmission system 2
If 0 'is used, the amount of phase change in the waveguide 11 can be accurately measured, and a highly reliable flow measurement result can be obtained. The phase detectors 222 and 223 and the phase comparator 226 can be incorporated in the measurement data processing system 15. Although the powder flow rate measuring devices 100-1 to 100-6 according to the above-described embodiment are applied to the measurement of the flow rate of coal ash, the flow rate measurement of powder other than coal ash, for example, the flow rate of flour in a silo The present invention can be effectively applied to measurement, flow rate measurement of powdery chemicals, powdery synthetic resin, and the like.

[0053]

To measure the flow rate of the powder using the microwave, the relation coefficient between the phase change amount of the microwave when the microwave is applied to the powder and the weight bulk density of the powder is measured. In the present invention, the relationship coefficient is set by actually measuring the phase change amount and the weight bulk density of the powder to be measured. Therefore, according to the present invention, the relation coefficient depends on the electrical characteristics of the powder to be measured (for example, in coal ash, it is greatly affected by the residual amount of unburned carbon, the moisture content, and the like). As a result, the measurement accuracy of the flow rate is dramatically improved. Further, the microwave transmission system connected to the waveguide means has a configuration for suppressing a phase change of the microwave, which also contributes to improvement of measurement accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a powder flow rate measuring device according to the present invention.

FIG. 2 is a waveform diagram illustrating a mode of a time change of a phase change amount in a waveguide for measuring a flow speed of ash.

FIG. 3 is a graph showing the relationship between the falling weight of ash measured by the apparatus of FIG. 1 and the actually measured weight of ash loaded on a truck.

FIG. 4 is a graph showing measured ash weights in a plurality of loading operations.

FIG. 5 is a schematic view showing another embodiment of the present invention in which a water adding section is added to the apparatus of FIG. 1 to discharge wet ash.

6 is a graph showing the relationship between the falling weight of ash measured by the apparatus of FIG. 5 and the actually measured weight of ash loaded on a truck.

FIG. 7 is a graph showing measured ash weights in a plurality of loading operations.

FIG. 8 is a schematic diagram showing another embodiment of the present invention having a configuration in which the number of waveguides is reduced by one.

FIG. 9 is a schematic sectional view showing a configuration of a lower on-off valve shown in FIG. 1;

FIG. 10 is a schematic sectional view showing a configuration of a lower on-off valve shown in FIG. 8;

11 is a schematic cross-sectional view showing the on-off valve of the on-off valve shown in FIG. 10 in which a valve hole is changed to a square cross section.

FIG. 12 is a schematic view showing another embodiment of the present invention in which a water adding section is added to the apparatus of FIG. 8 to discharge wet ash.

FIG. 13 is a schematic view showing another embodiment of the present invention having a configuration in which the number of waveguides is reduced by two.

14 is a schematic view showing another embodiment of the present invention in which a water adding section is added to the apparatus of FIG. 13 to discharge wet ash.

FIG. 15 is a block diagram showing a configuration of a transmission system for transmitting microwaves at a high frequency.

FIG. 16 is a graph illustrating the temperature dependence of the dielectric constant of a coaxial cable.

FIG. 17 is a block diagram showing a configuration of a transmission system that converts microwaves into light and transmits the light.

FIG. 18 is a block diagram showing a configuration of a transmission system for transmitting microwaves through a waveguide.

FIG. 19 is a block diagram showing a configuration of a transmission system configured to cancel a phase change occurring in a coaxial cable.

FIG. 20 is a schematic view illustrating the configuration of an ash discharge facility in a coal fuel combustion plant.

FIG. 21 is a schematic diagram showing a configuration of a conventional powder flow measuring device.

[Explanation of symbols]

 6 Ash storage tanks 7a, 7b, 7b '9 Transport vehicles 11a to 11c Waveguide 13 Microwave transmitter 15 Measurement data processing system 16 Microwave transmission material 19 Weight measuring device 20 Transmission system 30 Water addition unit 31 Water pipe 32 Flow rate Control valve 33 Flow rate system 40 Added water amount control section 76 Housing 76a Valve seat 77 Inlet 78 Exit 79 Valve member 79a Shaft 79b Valve hole 80 Ash flow path 81 Calibration section 82 Lower part of ash flow path 201, 213 Up-conversion mixers 202, 214 High-pass filters 204, 208 Down-converter mixers 205, 209 Low-pass filters 206, 207, 215, 216 High-frequency oscillator 210 Electric-optical converter 211 Coaxial cable 212 Optical-electric converter 217 Waveguide 221 Power divider 222, 223 Phase Detector 224, 225 Coaxial cable Bull 226 phase comparator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenya Fujita 1-1-1 Wadazakicho, Hyogo-ku, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries, Ltd., Kobe Shipyard (72) Inventor Hiroyuki Iwabuchi 2 Araimachi Shinhama, Takasago-shi, Hyogo 1-1-1, Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Keiichi Morishita 2-1-1, Araimachi, Arai-machi, Takasago-shi, Hyogo Prefecture Inside Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Kenji Iizuka Arai-cho, Takasago-shi, Hyogo 2-1-1 Niihama, Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Masaru Ishibashi 2-1-1, Niihama, Arai-machi, Takasago City, Hyogo Prefecture, Japan Inside Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Shinya Ishii Takasago, Hyogo Prefecture 2-1-1, Niihama, Arai-cho, Yokohama-shi F term in Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (reference) 2F035 A A04 DA01 DA03 DA04 DA08 DA15

Claims (10)

[Claims] 1. A relational coefficient between a phase change amount of a microwave and a powder bulk density when a microwave is applied to a powder is set in advance, and the relational coefficient, a flow speed of the powder, In a powder flow rate measuring device that measures the flow rate of the powder based on the cross-sectional area of the flow path of the powder and the phase change amount of the microwave, the weight and bulk density of the powder to be measured, A powder flow measuring device, characterized by further comprising a relation coefficient setting means for setting the relation coefficient by actually measuring the phase change amount of the applied microwave. 2. The calibration method according to claim 1, wherein said relation coefficient setting means is configured to divide said powder passage by a first on-off valve and a second on-off valve provided downstream of said first on-off valve. A first waveguide unit for applying microwaves to the powder filled in the calibration unit, and a weight measuring unit for measuring the weight of the powder filled in the calibration unit, The powder flow rate measuring device according to claim 1, wherein the relation coefficient is set based on the amount of phase change of the microwave in the waveguide means, the weight of the powder, and the volume of the calibration unit. 3. A water adding means for adding a predetermined fraction of water to said powder.
Or the powder flow measuring device according to 2. 4. A second and third waveguide means for applying microwaves to a powder flowing through a portion of the flow path of the powder downstream of the calibration portion at a predetermined interval. 4. The method according to claim 1, wherein the flow rate of the powder is measured based on the correlation between the phase change amounts of the microwaves in the second and third waveguide means. Powder flow measuring device. 5. A second on-off valve having a structure in which no protrusion is interposed in an internal flow path, and a microwave downstream of the calibration section is applied to powder flowing through the section. 3. The apparatus according to claim 2, further comprising a second wave guide means for acting, wherein the flow speed of the powder is measured based on a correlation between the phase change amounts of the microwaves in the first and second wave guide means. Or the powder flow rate measuring device according to 3. 6. The method according to claim 2, wherein the flow rate of the powder is measured using only the phase change amount of the microwave in the first waveguide under the condition that the flow speed of the powder is constant. 4. The powder flow rate measuring device according to 3. 7. A microwave transmission system connected to said waveguide means comprises: frequency conversion means for increasing the frequency of the input microwave; and a coaxial cable for transmitting the microwave having the increased frequency. 7. The powder flow rate measuring device according to claim 1, further comprising frequency conversion means for lowering the frequency of the microwave transmitted by the coaxial cable to the frequency of the input microwave. 8. A microwave transmission system connected to said waveguide means, a frequency conversion means for lowering the frequency of the inputted microwave to a frequency which can be converted into an optical signal, and an output of said frequency conversion means to an optical signal. Electro-optical conversion means for converting the optical signal, an optical fiber for transmitting the optical signal, an optical-electric conversion means for converting the optical signal transmitted by the optical fiber into an electric signal, The powder flow measuring device according to any one of claims 1 to 6, further comprising frequency conversion means for increasing a frequency to a frequency of the input microwave. 9. The powder flow rate measuring device according to claim 1, wherein the microwave transmission system connected to said waveguide means is a waveguide. 10. A microwave transmission system connected to the waveguide means, a distribution means for dividing the input microwave into two, and one of the microwaves distributed by the distribution means for transmitting the microwave to the waveguide. A first coaxial cable for supplying to the means and transmitting microwaves output from the waveguide means, and having the same characteristics and length as the first coaxial cable and distributed by the distribution means. A second coaxial cable for transmitting the other microwave and the first and second coaxial cables.
Phase detection means for detecting the phases of the first and second microwave signals respectively output from the coaxial cable of
The first microwave signal based on the phase of the second microwave signal;
7. The powder flow rate measuring device according to claim 1, further comprising: a phase comparing unit that extracts a phase of the microwave signal.