CN1229911A - Detecting method and appts. for flow of pipeline coal powder - Google Patents
Detecting method and appts. for flow of pipeline coal powder Download PDFInfo
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- CN1229911A CN1229911A CN 98112839 CN98112839A CN1229911A CN 1229911 A CN1229911 A CN 1229911A CN 98112839 CN98112839 CN 98112839 CN 98112839 A CN98112839 A CN 98112839A CN 1229911 A CN1229911 A CN 1229911A
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Abstract
A method and device for measuring the flow of powdered coal in pipeline uses the optical-fibre pressure sensor arranged on coal-delivering pipeline to detect the changes of pressure P and flowing speed V in pipeline, and the two signals proportional inversely are calculated based on a special equation by operating circuit to obtain the relative values of pressure, flowing speed and density of powdered coal in pipeline. It is suitable for large boil burning coal and features simple method, easy operation, and high sensitivity and stability.
Description
The invention belongs to the detection method of the interior pulverized coal flow of convey coal pipe in the coal-burning boiler and the improvement of device, relate to field of photoelectric technology.
The large coal-fired boiler that is widely used in the fuel-burning power plant is to rely on wind-force by pipeline coal dust to be sent in the stove, makes coal dust be injected in the burner hearth internal combustion with certain speed, make to reach optimal combustion state in the stove, and then the control by coal-air ratio realizes.Prior art is according to temperature in the stove, manually controls wind-force size and coal dust input quantity and make and reach optimal combustion state in the stove; Under metastable condition, this pattern is compiled into corresponding program by the people, and has realized the state demonstration.Because this boiler is very big, and many group nozzles are arranged, its temperature of measuring is the burner hearth integrated temperature, undesired or whole group nozzle at single-nozzle is not in optimal combustion state, be difficult to explanation with measured temperature, so just consider change, and constantly inwardly import coal dust less than stove internal combustion state; In addition because so the random variation of wind-force, coal dust humidity and quality is difficult to the best combustion in the realization stove; And the excessive input of coal dust causes rough burning, not only causes waste, the more important thing is that the stacking energy of coal dust in the stove causes the rising of pressure, has the danger of blast; And the deficiency of coal dust input also causes and produces waste and reduced generating efficiency.The inventor proposes a kind of detection method of coal-burning boiler combustion conditions in view of the above, and the size of adjusting coal-air ratio according to its testing result just can realize the best combustion in the stove, needs to learn the flow and the flow velocity of pipeline powder coal thus, and then the control injecting coal quantity.
Purpose of the present invention just provides a kind of detection method of pipeline powder coal flow, the big or small digitizing of pulverized coal flow, and for the control of injecting coal quantity provides foundation, and the design pick-up unit that this method implemented of sening as an envoy to.
The realization of technical solution of the present invention is finished by following requirement.The detection method of pipeline powder coal flow is: convey coal pipe is provided with fibre optic compression sensor and communicates with inner cavity of pipe, the variation of manifold pressure and flow velocity changes electric signal into by sensor, handles the relative value that just can obtain manifold pressure, flow velocity and coal dust density (ρ) through computing circuit again; Described computing circuit is ρ=2 (C-P) K/V
2Computing circuit, C is a constant in the formula, is that to make C-P, K at 0 o'clock be correction factor at ρ, the K value is in-1/2～-1/3 scope; Wherein pressure P and flow velocity V are then obtained after processing of circuit by the electric signal of sensor output.From the process of pipeline coal transporting as can be seen, in pipeline, add wind wind-force stable after, do not add coal dust as yet before, adjust constant C and equal the tube wall pressure P, make that the coal dust density p equals zero in the circuit, this moment tube wall pressure P minimum, and flow velocity V maximum; Along with the adding of coal dust, pressure P increases, and flow velocity reduces, and when the coal dust addition reached maximum, tube wall pressure was maximum, and flow velocity is minimum; So pressure P and the linear inverse relation of flow velocity V.Flow velocity V can obtain after processing of circuit by pressure P, also can be obtained by the signal of sensor acquisition and the pressure P relation of being inversely proportional to.
Feature of the present invention also is, the pick-up unit of realizing above-mentioned detection method is to be made of fibre optic compression sensor and computing circuit, wherein the structure of pressure transducer is for to have a flexible sheet that cavity is divided into inner chamber and exocoel at the sensor internal fixation, exocoel communicates with convey coal pipe, the variation of manifold pressure and flow velocity can cause that the convex-concave of flexible sheet changes, the inner cavity surface of flexible sheet is set to light reflection surface, the optical fiber sensor head that fixedly installs at the sensor inner chamber then can be determined the variation of manifold pressure by the variation of reception intensity of reflected light like this, promptly the light signal that receives is converted to electric signal by photoelectric commutator, handles just can obtain pressure again through computing circuit, the relative value of flow velocity and coal dust density.Optical fiber sensor head is by emitting optical fiber and receive optical fiber and constitute, and emitting optical fiber and reception optical fiber comprise reflection optical axis not on same optical axis; According to light trigonometry principle, along with receive catoptrical distance by near to far away, it is the strongest that being changed to of the intensity of reflected light that receives is strengthened to gradually, weakens gradually again; So the present invention is divided into two groups of settings receiving optical fiber, one group is arranged in the strongest distance of reflected light, the light intensity of reception is weakened gradually with the shortening of distance, and another group is arranged on beyond the strongest distance of reflected light, and the light intensity of reception is strengthened gradually with the shortening of distance; Sensor just can obtain two signals that are mutually inverse ratio like this, is set at pressure signal to one, and another then is a flow velocity signal.
Feature of the present invention also is, if sensor acquisition obtains is mono signal, can adopt microprocessor that its processing and correction are become two signals that are mutually inverse relation, carries out computing through computing circuit again; If what sensor acquisition obtained is two signals, can directly carry out computing with computing circuit.ρ of the present invention=2 (C-P) K/V
2The structure of computing circuit is, the pressure P signal is through dividing two tunnel, one tunnel output behind the operational amplifier, and another road 2 (C-P) treatment circuit obtains 2 (C-P) signal and transports to multiplier; Flow velocity signal becomes 1/V through operational amplifier
2Signal divides two the tunnel, the one tunnel to become V signal output through an arithmetical unit again, and another road is through K/V
2Treatment circuit obtains K/V
2Signal is transported in the multiplier, 2 (C-P) and K/V in multiplier
2Multiply each other and obtain the output of p signal.2 (C-P) and K/V wherein
2Two treatment circuits can be selected integrated package, the treatment circuit that also can select resolution element to constitute.
By as can be seen above-mentioned, according to the present invention designed detection method and device, can finish mensuration to the pipeline powder coal flow, obtain parameters such as pipeline pressure, flow velocity and coal dust density, realize purpose of the present invention, thereby for the detection and the control of boiler combustion operating mode provides foundation, make boiler reach optimal combustion state, enhance productivity, save and produce with coal, assurance safe operation.
Accompanying drawing 1 is the structural representation of a kind of example of the designed fibre optic compression sensor of the present invention, and accompanying drawing 2 is the designed ρ of the present invention=2 (C-P) K/V
2The structure principle chart of a kind of example of computing circuit, accompanying drawing 3 is a receiving light power degree (I) and the graph of relation that receives electrical distance (H) in the light trigonometry principle, accompanying drawing 4 is the structural representation of a kind of example of sensing head in the fibre optic compression sensor of the present invention, and accompanying drawing 5 is the end view of Fig. 4.1 is sensing head among the figure, and 2 is flexible sheet, and 3 is the flexible sheet holder, 4 is sensor outer housing, and 5 is convey coal pipe, and 6 is ball float, 7 is the sensing head holder, and 8 is photoelectric commutator, and 9 is light source, 10 is computing circuit, 11 is the optical fiber separation layer, and 12 is the inserts between the optical fiber, and 13 is that (outer ring) receives optical fibre set, 14 is (inner ring) emitting optical fiber group, and 15 is that (center) receives optical fibre set.
Describe specific embodiments of the present invention in detail below in conjunction with accompanying drawing.
The detection method of the pipeline powder coal flow that the present invention is designed is, is set with fiber-optic pressure sensor and communicates with inner cavity of pipe on convey coal pipe, and the variation of manifold pressure and flow velocity changes electric signal into by sensor, through ρ=2 (C-P) K/V
2Computing circuit is handled the relative value that just can obtain manifold pressure P, flow velocity V and coal dust density p.Described ρ=2 (C-P) K/V
2The structure of computing circuit is referring to Fig. 2, sensing head is collected two light signals that are mutually inverse ratio are transported to two photoelectric commutators respectively and are changed electric signal output into, a signal becomes the pressure P signal through operational amplifier and divides two the tunnel, one tunnel output, another road enters the arithmetical unit that is parallel with potentiometer, another input end at arithmetical unit is connected to adjustable potentiometer R, and 2 (C-P) signal that obtains after the computing is transported to multiplier; Another signal becomes 1/V through operational amplifier
2Signal divides two the tunnel, the one tunnel to become the output of flow velocity V signal through an arithmetical unit again, and another road enters the arithmetical unit that is parallel with adjustable potentiometer K, the K/V that obtains after the computing
2Signal is transported to multiplier, 2 (C-P) and K/V in multiplier
2Multiply each other and obtain the output of coal dust density p signal; If what sensing head collected is mono signal, then can adopts microprocessor exclusive disjunction device that it is treated as two signals that are mutually inverse ratio and get final product.Described operational amplifier can be selected the LM324 type.In fact, detection method of the present invention only need be talked clearly principle, and colleague's technician can both finish by several schemes, here narration no longer one by one.
The structure of described fibre optic compression sensor is referring to Fig. 1, in sensor outer housing 4, be set with flexible sheet 2 cavity is divided into inner chamber and exocoel by holder 3, flexible sheet can be selected the phosphor bronze diaphragm, thick 0.3mm, the inner cavity surface of diaphragm is a light reflection surface, and the size of diaphragm is decided by the size of shell 4; Have some apertures that exocoel is communicated with convey coal pipe 5 in the bottom of holder 3, the variation of manifold pressure and flow velocity can make diaphragm 2 produce distortion; For the distortion that makes diaphragm more converges, be provided with a ball float 6 in the bottom of holder 3, and ball float is had be no less than 1/5 part to expose in the pipeline 5, ball float can jack-up diaphragm 2 after being subjected to manifold pressure and fluid thrust, and ball float can adopt glass bead or hollow steel ball; Fixedly install optical fiber sensor head 1 at the sensor inner chamber by sensing head holder 7, make sensing head can receive the reflected light of diaphragm 2, the end of sensing head is connected with light source 9 and photoelectric commutator 8, photoelectric commutator is connected with computing circuit 10 again, and the pressure P that obtains after treatment, flow velocity V and density p electric signal are transported to outside the housing 4.The structure of described sensing head is referring to Fig. 4 and Fig. 5, optical fiber sensor head is made up of emitting optical fiber and reception optical fiber, emitting optical fiber 14 is arranged in the inner ring of sensing head, its end is connected in light source 9, receive optical fiber and divide two groups of settings, one group is positioned at sensing head center 15, and the end that another group is arranged in 13, two groups of the outer rings of sensing head is connected to photoelectric commutator 8; The axial arrangement of sensing head inner fiber (Fig. 4) is, the end face of center reception optical fiber 15 and the end face of emitting optical fiber 14 are on same plane, its distance (H) apart from diaphragm 2 by in the strongest distance (H ＇) of reception reflected light, promptly with diaphragm and its shortening apart from (H), the light intensity that is received (I) weakens gradually, referring to left side curve among Fig. 3, the end face that the outer ring receives optical fiber 13 is higher than the end face that receives optical fiber 15, in the strongest distance of reception reflected light (H ＇) in addition, promptly with shortening apart from (H), institute's receiving light power (I) strengthens gradually, referring to the right curve in the accompanying drawing 3.
The notion of the pressure P that proposes in the detection method of the present invention, flow velocity V and density p, only be to use the Several Factors that physical change in the coal chute represented in these several nouns, do not represent the notion on the practical significance, its numerical value that records also is the simulation electric weight that these combined factors change, so can not with P and V among (the especially limit hypothesis) the present invention that gets across of actual theory obtain and between relation, so the result who is measured by the present invention also only limits to the control of determining to reach the pipeline coal-air ratio of variation relatively of pipeline powder coal flow, face can not be done other purposes.The inventor makes a pick-up unit model machine according to described requirement, and through experimental test, under the constant situation of wind-force, when the coal amount was linear the change, measured P, V, three electric weight of ρ also were linear change, and is 0.5Kg/M at coal-air ratio
3, 1.0Kg/M
3, 1.5Kg/M
3The time, the electricity of the ρ that records is respectively put variation more than 1V, thereby illustrates that the present invention is feasible with the detection of main road pulverized coal flow, can be used in the detection of combustion conditions, meets the requirement to injecting coal quantity control, has reached purpose of the present invention.
To equal the adjustment of P be by the adjustment of potentiometer R is finished to C among the present invention, also can be by adjusting the potentiometer realization in parallel with arithmetical unit; P, the V that records when after disposable adjustment, various wind-force being changed, the electric weight input recognition system of ρ, the corrected parameter of P, V, ρ and being stored when determining various wind-force and change by it; In application, meet wind-force when changing, P, V, ρ value that recognition system then records with corresponding corrected parameter correction according at that time air output, the some of them details is the content of another invention, has no longer described in detail here.
Claims (5)
1. the detection method of a pipeline powder coal flow is to rely on the fibre optic compression sensor acquired signal that is arranged on the convey coal pipe, and changes them into two electric signal that are mutually inverse ratio, it is characterized in that, two signals through ρ=2 (C-P) K/V
2Computing circuit is handled, and can obtain the relative value of pressure P, flow velocity V and coal dust density p, and C is a constant in the formula, and K is a correction factor; When the coal dust density p is zero, adjusts constant C and equal pressure P.
2. detection method according to claim 1 is characterized in that, described ρ=2 (C-P) K/V
2Computing circuit structure is, two that obtain signals that are mutually the inverse ratio electric signal become the pressure P signal through operational amplifier divide two tunnel, one tunnel output, and another road 2 (C-P) processing of circuit obtains 2 (C-P) signal and transports to multiplier; Another signal is become 1/V through operational amplifier
2Signal divides two the tunnel, the one tunnel to become the output of flow velocity V signal through an arithmetical unit again, and another road is through K/V
2Processing of circuit obtains K/V
2Signal is transported in the multiplier, 2 (C-P) and K/V in multiplier
2Multiply each other and obtain the output of coal dust density p signal; Correction factor K value is in-1/3～-1/2 scope.
3. realize the pick-up unit of claim 1 and 2 described detection methods, it is characterized in that, the structure of described fibre optic compression sensor is, at the sensor housing internal fixation one flexible sheet is set cavity is divided into inner chamber and exocoel, exocoel communicates with convey coal pipe, the variation of manifold pressure and flow velocity can cause that the convex-concave of this diaphragm changes, the inner cavity surface of this diaphragm is a light reflection surface, be set with optical fiber sensor head alignment light reflecting surface at inner chamber, the emitting optical fiber end of optical fiber sensor head is provided with light source, its end that receives optical fiber is connected to photoelectric commutator, again through ρ=2 (C-P) K/V
2Handle, it is external that the P, the V that obtain and ρ signal are transported to sensor shell.
4. device according to claim 3, it is characterized in that, reception optical fiber in the described optical fiber sensor head divides two groups of settings, the termination of one group of optical fiber is concordant with the termination of emitting optical fiber, it in the strongest distance of reflected light, makes the light intensity of reception weaken gradually with the shortening of distance apart from the distance of light reflection surface; The termination of another group optical fiber is higher than the termination of emitting optical fiber, and it beyond the strongest distance of reflected light, makes the light intensity of reception strengthen gradually with the shortening of distance apart from the distance of light reflection surface; End at two group of received optical fiber connects two photoelectric commutators respectively, can obtain two electric signal that are mutually inverse ratio.
5. device according to claim 4 is characterized in that, is provided with a ball float in the diaphragm holder of sensor exocoel bottom, and ball float is had be no less than 1/5 part to expose in the pipeline, can the jack-up flexible sheet after ball float is stressed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 98112839 CN1229911A (en) | 1998-03-20 | 1998-03-20 | Detecting method and appts. for flow of pipeline coal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 98112839 CN1229911A (en) | 1998-03-20 | 1998-03-20 | Detecting method and appts. for flow of pipeline coal powder |
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| CN1229911A true CN1229911A (en) | 1999-09-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 98112839 Pending CN1229911A (en) | 1998-03-20 | 1998-03-20 | Detecting method and appts. for flow of pipeline coal powder |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101939591B (en) * | 2007-12-07 | 2012-10-10 | Abb技术有限公司 | A system and method for full combustion optimization for pulverized coal-fired steam boilers |
| CN103162748A (en) * | 2013-02-04 | 2013-06-19 | 中国科学院半导体研究所 | Optical floater flowmeter |
-
1998
- 1998-03-20 CN CN 98112839 patent/CN1229911A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101939591B (en) * | 2007-12-07 | 2012-10-10 | Abb技术有限公司 | A system and method for full combustion optimization for pulverized coal-fired steam boilers |
| CN103162748A (en) * | 2013-02-04 | 2013-06-19 | 中国科学院半导体研究所 | Optical floater flowmeter |
| CN103162748B (en) * | 2013-02-04 | 2016-01-20 | 中国科学院半导体研究所 | A kind of optical floater flowmeter |
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