The binary channels orifice plate gas flow measurement device of built-in multiparameter
The utility model relates to a kind of gas measurement device, especially a kind of binary channels orifice plate gas flow measurement device of built-in multiparameter.
In the existing gas flow measurement technology, the problem that the speed mode measuring principle exists low discharge accurately not measure, positive displacement measuring principle exist movable member and big flow measurement that the problem of limitation is arranged.So, the more employing speed modes of industrial gas flowmeter body measuring method, the resident is with the more employing positive displacements of gas meter measuring method.
In recent years, propose to adopt the thermal type gas quality flow measurement technology, it has the low discharge measurement features near other initiating, and measure output can Direct Digitalization, be easy to electronization.But the thermal type air flow measurement has technological difficulties: the impurity in the pipeline is for the influence of measuring sensor.Be embodied in: the various industrial gasses that flow in the pipeline, rock gas etc., all have fine suspended particle and oily matter, the reason owing to production technology has the impurity that quantity does not wait through regular meeting simultaneously.Even if when just entering pipeline be highly purified clean air, also may be because the impurity that carries of pipeline itself, and make gaseous contamination, thus make gas have impurity.What the impurity in the pipeline was very big may be owing to produce during pipe production, thereby it is very high to eliminate the technical difficulty of impurity, in reality, realize gas extremely pure be not unusual difficulty with impurity.Hot type is measured sensitive element, because suspended particle and oily matter are in time or the accumulation of incident in the gas, it shows as absorption or sticks together the sensitive element surface, thereby influences thermal effect such as its thermal convection, diffusion and distribution, causes measuring error.
As can be seen, after hot type was measured sensitive element and polluted by running environment and gas medium, error appearred in original measurement parameter of setting, i.e. our said data-bias.The reason that data-bias produces is not because the trouble or failure of measuring sensor, data-bias is not to show as instrument and meter simply can not work, it or not the deadlock of saying usually, but, measuring system has departed from the measuring accuracy requirement, other basic function is normal such as data processing functions such as demonstration communications.
In the speed mode flow measurement,, characteristics simple in structure, reliable, technology maturation are arranged such as orifice flowmeter.
Be full of the fluid of pipeline, during restriction device in they flow through pipeline, a fluid stream will form local contraction at the throttling element place of restriction device, thereby flow velocity is increased, and static pressure is low, falls so just produced pressure before and after throttling element, be pressure reduction, the flow of media flow is big more, and the pressure reduction that produces before and after throttling element is just big more, so orifice flowmeter can be weighed the size of fluid flow by measuring pressure reduction.This measuring method is a benchmark with energy conservation law and mobile continuity law.
Differential pressure flowmeter is the most widely used flowmeter of a class, and its use amount is occupied the first place in all kinds of flow instruments.In recent years, because the appearance of various new flowmeter, its use amount percentage descends gradually, but is still a most important class flowmeter at present.
(1) use maximum orifice-plate flowmeter sound constructions, stable and reliable for performance, long service life;
(2) have wide range of applications, still do not have any class flowmeter so far and can intend by comparison;
(3) detection piece and transmitter, Displaying Meter are convenient to scale economics production respectively by different manufacturers production.
(1) measuring accuracy is generally on the low side;
(2) rangeability is narrow, and generally only 3: 1-4: 1;
(3) on-the-spot mounting condition requires high;
(4) crushing big (finger-hole plate, nozzle etc.).
If, can solve the low discharge problems of measurement of orifice flowmeter, that is to say, can be from begin the flow measurement of gas near zero flow; So, such technology is pulling speed formula flowmeter performance significantly, also can be used for the huge resident of quantity size better and use gas meter, and particularly field such as natural gas meter has important social and economic benefit.
Summary of the invention
The utility model has solved in the prior art when using pipeline to carry out gas flow measurement, be difficult to technical matters that gas low discharge in the pipeline is measured, provide a kind of reasonable in design, simple in structure, can begin to measure from the smile flow, and can effectively eliminate impurity effect, and prolong pick-up unit serviceable life, reduce the binary channels orifice plate gas flow measurement device of the built-in multiparameter of use cost.
The technical scheme that its technical matters that solves the utility model adopts is: a kind of binary channels orifice plate gas flow measurement device of built-in multiparameter, comprise the gas flow measurement pipe, narrow meshed orifice plate in the middle of the measuring tube internal fixation has, described orifice plate has enough thickness, measure the measurement mechanism that is connected on the tube wall across orifice plate, measurement mechanism mainly comprises pressure transducer, the upstream of one termination orifice plate of pressure transducer, the downstream of another termination orifice plate of pressure transducer, pressure transducer connects data handling system, at least be provided with the installation portion of a depression on the hole wall of the aperture of orifice plate middle part, wherein, at least be provided with the installation portion of a depression on the hole wall of the aperture of orifice plate middle part, one of them installation portion is fixed with hot type and measures sensitive element, the surface of hot type measurement sensitive element and the hole wall shape of aperture are at a tilt angle, the edge, windward side of hot type measurement sensitive element is mutually concordant with hole wall, orifice plate inside is provided with from installation portion and is connected to the line passage of measuring outside the tube wall, is furnished with in the line passage to connect the data line that hot type is measured sensitive element and data handling system; Differential pressure pick-up and hot type are measured there is mutually noninterfere in sensitive element to the measurement result of tested steam flow rate-of flow redundant overlapping region.Narrow meshed orifice plate in the middle of gas flow measurement pipe internal fixation has, and on the tube wall of measuring tube, be provided with the pressure transducer of measuring diaphragm upstream and downstream pressure reduction and handle by data handling system, this structure is equivalent to typical pore plate flow measurement device, the scope that can measure is 6.0m/s-20.0m/s, improve the precision of differential pressure pickup, the scope of measuring can narrow down to 2.0m/s, hot type is set on the aperture hole wall of the orifice plate middle part in measuring tube measures sensitive element, realize the common factor measurement of hot type measuring technique and orifice plate speed mode measuring technique, the measurement range that hot type measurement sensitive element can reach is 0.01m/s-15m/s, can measure tiny flow quantity like this, differential pressure measurement passage and small amount of flow measuring bypass bridge circuit are separate, mutually noninterfere during measurement, installation portion on the aperture hole wall can have a plurality of, is provided with according to the parameter of gas flow needs; Have gas stream out-of-date in pipeline, measurement synchronization such as differential pressure and hot type are carried out the surveying work of flow and other parameter; If when gas flow rate was in the low discharge zone that orifice flowmeter is difficult to accurately to measure, the measurement of orifice plate principle did not produce accurate flow measurement signal, but the hot type measuring technique can accurately be measured small gas flow; When air-flow in the pipeline is operated in the flow region that orifice flowmeter can accurately measure, the measurement of the measurement of orifice plate principle and hot type principle all can and effectively be measured the gas flow rate that flows through synchronously, measure passage for two and finished redundant measurement, and then carry out effective drift correction, improved the stability and the reliability of flow measurement.
A kind of scheme: described orifice plate is structure as a whole, and the orifice plate interference is fixed on the measuring tube inwall, measures tube wall and offers circular hole, fixedly circular hole alignment line passage behind the orifice plate.The orifice plate of integrative-structure can adopt metal to make, and it is interference fit that orifice plate is fixed on the measuring tube inwall
Another kind of scheme: described orifice plate is divided into into two for dividing body structure, and parting plane is through the axis of orifice plate, and the aperture on the orifice plate is made of the semicircular pillar chamber in the middle of two branch orifice plates.
Line passage on the orifice plate is arranged on the parting plane of orifice plate.
As preferably, installation portion is two, measures the sensitive element except installing and fixing hot type, also is mounted with temperature sensor.
As preferably, installation portion is on same circumferential plane, perhaps on different circumferential plane.
As preferably, the orifice plate in the measuring tube is provided with some through holes, and through hole is with respect to middle aperture symmetric arrangement.
If orifice plate is divided into two for dividing body structure, with the axis of parting plane through orifice plate, the middle aperture and the through hole of symmetrical aperture are on the parting plane of orifice plate.Such two orifice plates are symmetrical, and it is also convenient to make; If through hole is three, then can be on same parting plane with two through holes and middle aperture, another through hole like this can simplified structure not on parting plane.
When air-flow in the pipeline is operated in the flow region that orifice flowmeter can accurately measure, it is only relevant to gas flow rate to give full play to the orifice flowmeter measuring-signal, and, obtain the flow velocity under the gas duty to the big or small irrelevant measuring principle of the temperature, pressure quality of gas medium itself.Carry out the measurement of gas mass flow by the hot type measuring technique, calculate by the compensation of temperature, pressure measurement signal synchronously, can compare twin-channel measurement result.So, as long as having with the measurement range of pore plate flow measurement device, the measurement range of hot type measuring technique occurs simultaneously, just realized adaptively correcting; Simultaneously,, make the interior gas flow of pipeline stationary state occur, just realized hot type measuring sensor school zero and the online replacing of carrying out this pick-up unit by the switching valve of operations flows measuring device.
Owing to there is the phenomenon of gaseous contamination, differential pressure pick-up and hot type are measured the problem that can exist actual measured results not wait between the sensitive element, just need measure sensitive element correction to hot type this moment, realizes the condition of a correction by the microelectronics micro mechanical technology: the family curve funtcional relationship f that supposes hot type measurement sensitive element
(v, t)Remain unchanged, the zero point drift that requires hot type to measure sensitive element simultaneously can effectively be controlled in the accuracy rating.Referring to accompanying drawing 6, transverse axis is gas flow rate V
(t), number axis is voltage signal Y
(v, t)+ α
(t)A coefficient of representative function, α
(t)At the zero point of representative function, calibration function 9 is at Vt
2Between measurement result equate that with the measurement result of differential pressure pick-up after after a while, gas medium is contaminated, causes K
(t)Descend, actual measurement function 10 occurs, get V (t
2) between V (t
i), on calibration function, draw Y (t
i), on the actual measurement function, draw Y ' (t
i), Y ' (t
i) and Y (t
i) between have Δ Y, if Δ Y surpasses the precision that hot type is measured sensitive element,, then need to determine the K that revises such as 〉=1.0%
(t)Be worth K ' (
t), because funtcional relationship remains unchanged, therefore meet calibration function again through the function of revising, the measured value less than the overlapping region that actual measurement draws becomes real actual measured value after revising, the numerical value at zero point can form the numerical value of a no flow velocity by the valve of closing bypass bridge circuit two ends.
The beneficial effects of the utility model are: the minimum flow measurement has been extended to heat type gas flow detected the small flow velocity that can measure, range ratio was greater than 1: 100.Simultaneously, the elementary errors pressure passageway and the bypass bridge circuit of measuring diaphragm element are installed in outside the pipeline, are convenient for changing the sensitive measurement element; Particularly finish heat type gas flow and detect, avoided of the direct impact of the interior impurity of pipeline, thereby improved whole reliability the measuring sensor of sensitivity at the bypass bridge circuit.Two measurement ranges of measuring passage based on hot type measuring technique and pore plate flow measurement device are occured simultaneously, and realize knowing clearly redundant measurement, by automatic Verification and school zero power energy, whole measuring accuracy and stability are improved greatly.The present invention can measure the large diameter pipeline airshed, also can be used for small-bore resident and use the gas flow instrument, breaks through the limitation of the measurement range of flowmeter in the past; With respect to ultrasonic measuring device, its manufacturing cost and use cost is cheap.
Description of drawings
Fig. 1 is a kind of structural representation of the utility model;
Fig. 2 is a kind of three-dimensional cutaway view of the utility model;
Fig. 3 is the another kind of three-dimensional cutaway view of the utility model;
Fig. 4 is the synoptic diagram of a kind of orifice plate of the present utility model;
Fig. 5 is a kind of partial enlarged drawing of the present utility model;
Fig. 6 is a kind of measurement functions graph of a relation of the present utility model;
Among the figure: 1, measuring tube, 2, orifice plate, 3, the line passage, 4, hot type measures sensitive element, 5, aperture, 6, pressure transducer, 7, installation portion, 8, through hole, 9, calibration function, 10, the actual measurement function.
Below by specific embodiment, and in conjunction with the accompanying drawings, the technical solution of the utility model is described in further detail.
Embodiment 1: a kind of binary channels orifice plate gas flow measurement device of built-in multiparameter (referring to accompanying drawing 1 accompanying drawing 2 accompanying drawings 5), comprise gas flow measurement pipe 1, the orifice plate 2 of band aperture 5 in the middle of the measuring tube internal fixation has, described orifice plate has enough thickness, measure the measurement mechanism that is connected on the tube wall across orifice plate, measurement mechanism mainly comprises pressure transducer 6, the upstream of one termination orifice plate of pressure transducer, the downstream of another termination orifice plate of pressure transducer, pressure transducer connects data handling system, the hole wall of the aperture of orifice plate middle part is provided with the installation portion 7 of 2 depressions, two installation portions are on the same periphery of axis direction, one of them installation portion is fixed with hot type and measures sensitive element 4, another installation portion fixed temperature sensor, the hole wall of the surface of hot type measurement sensitive element and the surface of temperature sensor and aperture forms the angle of an inclination, the edge, windward side of hot type measurement sensitive element is mutually concordant with hole wall, orifice plate inside is provided with from installation portion and is connected to the line passage of measuring outside the tube wall 3, is furnished with in the line passage to connect the data line that hot type is measured sensitive element and data handling system; Orifice plate is structure as a whole, and is processed by a metal integral, and the orifice plate interference is fixed on the measuring tube inwall, measures tube wall and offers circular hole, fixedly circular hole alignment line passage behind the orifice plate.
Embodiment 2: a kind of binary channels orifice plate gas flow measurement device (referring to accompanying drawing 3) of built-in multiparameter, orifice plate is divided into into two for dividing body structure, parting plane is through the axis of orifice plate, and the aperture on the orifice plate is combined by the semicircular pillar chamber in the middle of two branch orifice plates; Line passage on the orifice plate is arranged on the parting plane of orifice plate, and all the other structures are with reference to embodiment 1.
Embodiment 3: a kind of binary channels orifice plate gas flow measurement device (referring to accompanying drawing 4) of built-in multiparameter, the orifice plate in the measuring tube is provided with 1 aperture, 2 through holes 8, aperture are in the centre position of orifice plate, through hole on the aperture limit with respect to the aperture symmetry; If orifice plate is arranged in through hole and aperture on the parting plane simultaneously for dividing body structure.
Above-described embodiment is several preferred version of the present utility model, is not the utility model is done any pro forma restriction, also has other variant and remodeling under the prerequisite that does not exceed the technical scheme that claim puts down in writing.