CN201138333Y - Microwave cavity sensor for steam dampness on-line detection - Google Patents
Microwave cavity sensor for steam dampness on-line detection Download PDFInfo
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- CN201138333Y CN201138333Y CNU2007201383054U CN200720138305U CN201138333Y CN 201138333 Y CN201138333 Y CN 201138333Y CN U2007201383054 U CNU2007201383054 U CN U2007201383054U CN 200720138305 U CN200720138305 U CN 200720138305U CN 201138333 Y CN201138333 Y CN 201138333Y
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Abstract
The utility model relates to a microwave cavity sensor for the on-line detection of steam moisture, which belongs to the testing technical field and which is used to solve the detecting problem of steam moisture. The microwave cavity sensor has the following technical proposal: the microwave cavity sensor comprises a cylindrical cavity which is opened at the two ends and has a transmission interface of microwave signal in the middle. The two ends of the cylindrical cavity inside are respectively provided with a ring separator. The ring separator is made up of 1 to 4 cylinders which are coaxial with the cylindrical cavity. The ends of the cylinders near the port of the cylindrical cavity are connected with the cylindrical cavity. The swell factor of the ring separator is greater than that of the cylindrical cavity. With the advantages of simple structure, convenient use and low requirement on environment, the microwave cavity sensor can be used together with the processing circuit of microwave signal to realize the high-precision on-line measurement of the humidity of flowing steam.
Description
Technical field
The utility model relates to a kind of steam moisture sensor, can carry out accurate online detection to steam moisture, belongs to technical field of measurement and test.
Background technology
Steam moisture all has material impact to the security performance and the economical operation performance of steam turbine, therefore is necessary steam turbine exhaust steam moisture is carried out on-line monitoring.Existing steam wetness measurement method mainly is divided into two classes, both thermodynamic method and optical method.Wherein, thermodynamic method is divided into flow limit method, coagulation, steam-air mixed method and heating again, and the monitoring mechanism and the relative merits of the whole bag of tricks are as follows:
The throttling ratio juris is that the sample that will extract is throttled to lower pressure, makes the steam after the throttling be in superheat state, obtains the humidity value that extracts sample steam according to enthalpy permanence condition before and after the throttling.The shortcoming of flow limit method is should not be used for measuring low-pressure area and humidity greater than 8% wet steam (exhaust steam pressure of general condensing turbine is lower, and humidity is in 6～12% scopes).In addition, thermal loss and wet steam expand
Mix the accuracy that also can influence measurement.
Coagulation is that the wet steam sample that will be extracted condenses into water in condenser, and the steam that absorbs according to chilled water in the condenser heat that condenses calculates the humidity of the sample that extracts.This method need be measured a plurality of parameters such as the sample flow of wet steam, cooling water inflow, water temperatures, may produce bigger measurement cumulative errors, and radiation loss simultaneously also can influence the accuracy of measurement, so measuring accuracy is lower.
Steam-air mixed method is that the sample that will be extracted mixes under adiabatic condition with the dry air of external world's introducing in a mixing chamber, according to the mass-energy conservation equation, obtains the humidity that extracts sample.During measurement,
Ask guarantee wet steam and dry air mix after, water loading of the air does not reach capacity as yet, therefore needs a large amount of hot-airs, this just requires to dispose the vacuum pump that capacity is very big in measure field, so has limited application at the scene.
Heating is that the saturated wet steam sample that will extract is heated to dried state of saturation or superheat state, measures the flow of steam sample, according to the caloric receptivity of sample and the variation of heating front and back sample thermal parameter, calculates the humidity of steam.Heating need be to sample flow, add a plurality of parameters such as heat, steam parameter measures, and measuring cumulative errors and radiation loss meeting influences measuring accuracy.
Generally speaking, above-mentioned various thermodynamic methods all need during measurement to extract the part sample the main steam flow in steam turbine, and not only measurement links is many, and the measurement mechanism complexity, and measuring accuracy is low.
Optical method is measured steam moisture and is based upon on the scattering of light principle basis, when light when containing the wet steam flow of water droplet, be subjected to the influence of water droplet light scattering effect in the steam, part light produces scattering phenomenon, therefore transmitted light intensity is less than incident intensity, thereby by measuring wet steam drop diameter in the wet steam, water droplet quantity and steam moisture obtained in scattering of light or decay.
Optical measuring method need not aspirate sampling, and the parameter that needs to measure is also lacked, and operates easier.Its shortcoming has two: first, one of key of optical method success is to keep the cleaning of optical window, generally adopt logical warm air to keep window surface not contact with water at present with greasy dirt, if being exposed to, measures in the steam flow optical window long period, its surface is subjected to polluting and is difficult to avoid, and the strict demand of measurement environment has been limited its application in practice; The second, when optical method is measured steam moisture, need measure respectively primary droplet and secondary water droplet, the measuring technique of primary droplet is ripe, but the secondary water droplet is not also had ripe measuring technique.As only primary droplet being measured, ignore the secondary water droplet in the wet steam, because the quality of water droplet becomes three cubed relation with diameter, its measurement result must be lower than actual value.Even can measure the secondary water droplet, because the optical measurement window is very little, and the unevenness that the secondary water droplet distributes is very big, may be because there is than mistake measurement result in sampling bias.
In a word, existing steam wetness measurement method and measurement mechanism thereof all exist wretched insufficiency, design a kind of simple in structure, adaptive capacity to environment is strong, the steam moisture sensor of cheap for manufacturing cost, function admirable, in order to online detection steam moisture, be very necessary to security and the economy that improves steam turbine.
Summary of the invention
The utility model be used to overcome prior art defective, provide a kind of simple in structure, measuring accuracy is high, the microwave resonance cavity sensor that is used for the online detection of steam moisture that adaptive capacity to environment is strong.
The alleged problem of the utility model realizes with following technical proposals:
A kind of microwave resonance cavity sensor that is used for the online detection of steam moisture, it comprises that there is the cylindrical cavity of microwave signal transmission interface both ends open, a centre, at the two ends of cylindrical cavity inside an annulus separation scraper is set respectively, described annulus separation scraper is formed with the coaxial cylinder of cylindrical cavity by 1～4, they are connected with cylindrical cavity near an end of cylindrical cavity port, and the expansion coefficient of annulus separation scraper is bigger than cylindrical cavity.
The above-mentioned microwave resonance cavity sensor that is used for the online detection of steam moisture, the wall that described cylindrical cavity air-flow flows into end is a wedge structure.
The above-mentioned microwave resonance cavity sensor that is used for the online detection of steam moisture, described annulus separation scraper is made of the metal fine-structure mesh.
The above-mentioned microwave resonance cavity sensor that is used for the online detection of steam moisture, described cylindrical cavity is by constituting by wedge shape cylinder 1, middle cylinder 3 and the regulating sleeve 6 that is threaded successively, the wall of described wedge shape cylinder 1 is a wedge structure, utilizes dog screw 5 to be fixed between described regulating sleeve 6 and middle cylinder.
The above-mentioned microwave resonance cavity sensor that is used for the online detection of steam moisture, the interface of described connection microwave signal transmission waveguide is an elliptical aperture, and elliptical aperture major and minor axis radius ratio is 1: 0.4, and the major axis of elliptical aperture is identical with the resonator axis direction.
The utility model constitutes microwave cavity with cylindrical cavity and annulus separation scraper, and the resonator cavity resonant frequency signal with the steam moisture conversion of signals becomes to be easy to measure measurement mechanism is simplified greatly, and sensor is not high to environment requirement.The annulus separation scraper adopts the metal fine-structure mesh to constitute, and both can allow two phase flow of damp steam freely pass through resonator cavity under the less situation of resistance, has guaranteed that again resonator cavity has high quality factor; The annulus separation scraper adopts the expansion coefficient metal material bigger than cylindrical cavity to make, stretch into the length of cylindrical cavity by appropriate design annulus separation scraper, in the time of can making tested wet steam temperature variation, the expansion of cylindrical cavity and separation scraper is cancelled out each other to the influence of resonator cavity resonance frequency, thus the influence that makes measurement result not changed by vapor (steam) temperature; It is a wedge structure that the air-flow of cylindrical cavity flows into end wall surface, can make the two phase flow of damp steam parameter that enters resonator cavity consistent with the main flow parameter, reduces sampling bias to greatest extent.The utility model is simple in structure, and is easy to use, low to environment requirement, cooperates with the microwave signal treatment circuit, can realize the high-precision of flowing wet steam humidity
On-line measurement.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is a structural representation of the present utility model;
Fig. 2 is the structural representation of wedge shape cylinder;
Fig. 3 is the left view of Fig. 2;
Fig. 4 is the structural representation of annulus dispenser;
Fig. 5 is the left view of Fig. 4;
Fig. 6 is the structural representation of middle cylinder;
Fig. 7 is the left view figure of Fig. 6;
Fig. 8 is the structural representation of regulating sleeve;
Fig. 9 is the left view of Fig. 8.
Each label is among the figure: 1, wedge shape cylinder, 2, the annulus dispenser, 3, middle cylinder, 4, rectangular waveguide, 5, dog screw, 6, regulating sleeve.
Embodiment
The variation of medium specific inductive capacity will cause the change of resonator cavity resonance frequency in the microwave cavity, by measuring the resonator cavity change of resonance frequency, can measure medium specific inductive capacity or its variable quantity in the resonator cavity.Under the certain pressure (temperature), different its specific inductive capacity of the humidity of wet steam are also just different, and both are corresponding one by one, therefore, can detect the humidity of wet steam by the specific inductive capacity of measuring wet steam in the microwave cavity.
Utilize microwave cavity to measure steam moisture, the resonator cavity change of resonance frequency realizes when flowing through microwave cavity by measuring two phase flow of damp steam, have higher accuracy and degree of accuracy in order to make to measure, the microwave resonance cavity sensor that is used to detect two phase flow of damp steam humidity should have good two-phase flow aerodynamic characteristic, high-frequency electromagnetic characteristic and low temperature sensitivity, both satisfied following requirement: the two phase flow of damp steam parameter that (1) enters resonator cavity is consistent with the main flow parameter, and sampling bias is little; (2) two phase flow of damp steam can freely pass through resonator cavity, and steam flow resistance to flow by resonator cavity the time is little, and resonator cavity has good two-phase flow aerodynamic characteristic; (3) resonator cavity has high quality factor; (4) the wet steam variation of temperature can not cause the change of resonator cavity resonance frequency.
Referring to Fig. 1, cylindrical cavity is by constituting by wedge shape cylinder 1, middle cylinder 3 and the regulating sleeve 6 that is threaded successively.The wall of wedge shape cylinder 1 inlet end is a wedge structure, and the annulus dispenser of airflow inlet is fixed between wedge shape cylinder 1 and the middle cylinder 3, and the annulus dispenser of air stream outlet is fixed on the regulating sleeve 6.During concrete enforcement, cylindrical cavity with and with the connected mode of annulus dispenser multiple variation can be arranged.For guaranteeing that sampling error is little, the internal diameter of wedge shape cylinder 1 and middle cylinder 3 should be consistent.
Referring to Fig. 4, Fig. 5, the annulus dispenser is made up of three equidistant equal thickness fine-structure mesh annulus, and this annular fine-structure mesh separator structure both can allow two phase flow of damp steam freely pass through resonator cavity, steam flow resistance to flow by resonator cavity the time is less, has guaranteed that again resonator cavity has high quality factor; Resonator cavity cavity and the annulus separation scraper at two ends adopt the metal material of different expansion coefficient respectively, the cylindrical shape resonator cavity adopts low-expansion material, two ends annulus separation scraper adopts high-expansion material, difference according to two kinds of material expansion coefficient that adopt, stretch into the length of resonator cavity by design two ends annulus separation scraper, make when tested wet steam temperature variation, the expansion of resonator cavity cavity and two ends separation scraper is cancelled out each other to the influence of resonator cavity resonance frequency, thereby makes the influence that measurement is not changed by vapor (steam) temperature.
Referring to Fig. 2, Fig. 3, it is a wedge structure that the air-flow of resonator cavity flows into end wall surface, and this structure can make the two phase flow of damp steam parameter that enters resonator cavity consistent with the main flow parameter, does not have sampling bias.
Referring to Fig. 6, Fig. 7, cylindrical shape wall central authorities at resonator cavity have an elliptical aperture, and elliptical aperture major and minor axis radius ratio is 1: 0.4, and the major axis of elliptical aperture is identical with the resonator axis direction, resonator cavity carries out the microwave signal transmission by this elliptical aperture and rectangular waveguide coupling.
Referring to Fig. 8, Fig. 9, regulating sleeve 6 is used to regulate the length of resonator cavity, and rotary regulating sleeve letter 6 can be regulated two distances between the annulus dispenser, regulates resonance frequency, and dog screw 5 is used for regulating sleeve 6 fixing with middle cylinder 3.
When measuring wet steam humidity, resonator axis is consistent with airflow direction, allows the wet steam free flow cross resonator cavity, draws the steam moisture that flows through resonator cavity by measuring the resonator cavity change of resonance frequency.
Claims (5)
1, a kind of microwave resonance cavity sensor that is used for the online detection of steam moisture is characterized in that, it comprises that both ends open, a centre are provided with the cylindrical cavity of microwave signal transmission interface, in two of cylindrical cavity inside
An annulus separation scraper is set respectively, and described annulus separation scraper is formed with the coaxial cylinder of cylindrical cavity by 1～4, and their are connected with cylindrical cavity near an end of cylindrical cavity port, and the expansion coefficient of annulus separation scraper is bigger than cylindrical cavity.
According to the described microwave resonance cavity sensor that is used for the online detection of steam moisture of claim 1, it is characterized in that 2, the wall that described cylindrical cavity air-flow flows into end is a wedge structure.
According to claim 1 or the 2 described microwave resonance cavity sensors that are used for the online detection of steam moisture, it is characterized in that 3, described cylindrical cavity is by wedge shape cylinder (1), middle cylinder 3 and by being threaded successively
Joint sleeve (6) constitutes, and the wall of described wedge shape cylinder (1) is a wedge structure, utilizes dog screw (5) to be fixed between described regulating sleeve (6) and middle cylinder.
4, according to the described microwave resonance cavity sensor that is used for the online detection of steam moisture of claim 3, it is characterized in that described annulus separation scraper is made of the metal fine-structure mesh.
5, according to the described microwave resonance cavity sensor that is used for the online detection of steam moisture of claim 4, it is characterized in that, the interface of described connection microwave signal transmission waveguide is an elliptical aperture, and elliptical aperture major and minor axis radius ratio is 1: 0.4, and the major axis of elliptical aperture is identical with the resonator axis direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201383054U CN201138333Y (en) | 2007-12-19 | 2007-12-19 | Microwave cavity sensor for steam dampness on-line detection |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201383054U CN201138333Y (en) | 2007-12-19 | 2007-12-19 | Microwave cavity sensor for steam dampness on-line detection |
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| CN201138333Y true CN201138333Y (en) | 2008-10-22 |
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| CNU2007201383054U Expired - Fee Related CN201138333Y (en) | 2007-12-19 | 2007-12-19 | Microwave cavity sensor for steam dampness on-line detection |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101183081B (en) * | 2007-12-19 | 2010-08-11 | 华北电力大学 | Microwave sensor used for detecting steam humidity |
| CN103592318A (en) * | 2013-10-28 | 2014-02-19 | 华北电力大学（保定） | Two-channel microstrip slot steam turbine steam humidity sensor |
| CN104568992A (en) * | 2014-12-03 | 2015-04-29 | 国网河南省电力公司电力科学研究院 | Microwave resonant cavity capable of automatically following steam exhaust direction |
| CN105866141A (en) * | 2016-04-29 | 2016-08-17 | 华北电力大学（保定） | Dual-mode four-channel steam turbine steam humidity measuring system and method |
| CN106442651A (en) * | 2016-11-28 | 2017-02-22 | 华北电力大学（保定） | Micro-strip chip resonator for measuring humidity of steam turbine |
| CN108321485A (en) * | 2018-03-05 | 2018-07-24 | 华北电力大学（保定） | A kind of microwave resonance cavity and steam turbine last stage humidity detector |
| CN112798621A (en) * | 2020-12-25 | 2021-05-14 | 孟敏 | Icing and dewing detection device and method based on S-shaped microwave transmission line |
| CN113251091A (en) * | 2021-07-01 | 2021-08-13 | 江苏永衡土木减隔震工程技术研究院有限公司 | Adjustable eddy current damper |
-
2007
- 2007-12-19 CN CNU2007201383054U patent/CN201138333Y/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101183081B (en) * | 2007-12-19 | 2010-08-11 | 华北电力大学 | Microwave sensor used for detecting steam humidity |
| CN103592318B (en) * | 2013-10-28 | 2016-01-27 | 华北电力大学（保定） | Two-channel microstrip slot steam turbine steam humidity sensor |
| CN103592318A (en) * | 2013-10-28 | 2014-02-19 | 华北电力大学（保定） | Two-channel microstrip slot steam turbine steam humidity sensor |
| CN104568992B (en) * | 2014-12-03 | 2017-03-15 | 国网河南省电力公司电力科学研究院 | The microwave cavity in steam discharge direction is followed automatically |
| CN104568992A (en) * | 2014-12-03 | 2015-04-29 | 国网河南省电力公司电力科学研究院 | Microwave resonant cavity capable of automatically following steam exhaust direction |
| CN105866141A (en) * | 2016-04-29 | 2016-08-17 | 华北电力大学（保定） | Dual-mode four-channel steam turbine steam humidity measuring system and method |
| CN105866141B (en) * | 2016-04-29 | 2018-05-18 | 华北电力大学（保定） | A kind of bimodulus four-way steam-turbine humidity measurement system and method |
| CN106442651A (en) * | 2016-11-28 | 2017-02-22 | 华北电力大学（保定） | Micro-strip chip resonator for measuring humidity of steam turbine |
| CN108321485A (en) * | 2018-03-05 | 2018-07-24 | 华北电力大学（保定） | A kind of microwave resonance cavity and steam turbine last stage humidity detector |
| CN112798621A (en) * | 2020-12-25 | 2021-05-14 | 孟敏 | Icing and dewing detection device and method based on S-shaped microwave transmission line |
| CN112798621B (en) * | 2020-12-25 | 2021-10-08 | 孟敏 | Icing and dewing detection device and method based on S-shaped microwave transmission line |
| CN113251091A (en) * | 2021-07-01 | 2021-08-13 | 江苏永衡土木减隔震工程技术研究院有限公司 | Adjustable eddy current damper |
| CN113251091B (en) * | 2021-07-01 | 2021-10-15 | 江苏永衡土木减隔震工程技术研究院有限公司 | Adjustable eddy current damper |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081022 Termination date: 20121219 |