A kind of force-measuring type optical fibre flowmeter
Technical field
The present invention relates to the flow rate test technical field, relate in particular to a kind of force-measuring type optical fibre flowmeter, be applicable to measure the flow of fluid.
Background technology
In a lot of fields of commercial production and people's lives, all need the flow of convection cell to monitor.At present, target type meter commonly used is when flowing through target plate by liquid target plate to be produced pressure, make target plate band moving-target bar produce microdisplacement, record displacement and displacement is converted to electric signal input analytical equipment by electric transducer and calculate, draw at last flow number.But, the electrical type sensor exist poor, the easy electric leakage of sealing, perishable, be subjected to the problems such as electromagnetic interference (EMI).
Fibre Optical Sensor adopts optical fiber to carry out sensing and transmission, does not have the problems referred to above, has therefore in recent years obtained increasing attention.But still there is more problem in present optical fibre flowmeter.
The people such as Li Chuan have proposed a kind of target type fiber grating liquid flowmeter (Chinese invention patent application 200910094845.0), the pressure on the choked flow target that this flowmeter adopts a series of transmission mechanisms such as choked flow target, connecting rod, cantilever that fluid is caused passes to fiber grating, and the variation by grating spectrum records flow.The deficiency of this design is: 1) the choked flow target has affected flow field and the flow in original pipeline; 2) need to increase the shaft seal sheet, strip hole etc. is set, technique and complex structure especially need this movable agency of connecting rod is sealed, and reliability is low.
The people such as Zhang Qiang have proposed " with the fiber grating liquid flow sensor of temperature compensation " (Chinese invention patent application 200910229030.9) equally, adopt " elasticity tongue " to experience the pressure that fluid causes in this sensor, its deficiency is: 1) elasticity tongue itself can affect original ducted flow and flow field characteristic equally; 2) direction of fiber grating and flow direction are not parallel, and Fluid Flow in A can produce extra-stress to fiber grating, thereby affect measuring accuracy.
The people such as Gao Yingjun also disclose a kind of similar structure in utility model patent " optical fiber raster flow sensor ", this structure adopts the method that fiber grating is arranged on " tablet " to carry out flow measurement, and tablet is experienced the pressure of fluid.This scheme exists and above-mentioned two deficiencies that scheme is identical: tablet can affect original ducted flow and flow field characteristic equally.In addition, fiber grating and tablet are connected as a single entity to produce easily and warble, thereby affect measuring accuracy.
Therefore, how to make flowmeter not affect flow and the flow field of former pipeline, make optical fiber not be subjected to the impact of other adjection and improve sensitivity, and structure and the technique of simplifying flowmeter, the problem that optical fibre flowmeter is needed solution at present badly become.
Summary of the invention
The technical matters that (one) will solve
In view of this, fundamental purpose of the present invention is to provide a kind of force-measuring type optical fibre flowmeter, affects flow and the flow field of former pipeline to solve flowmeter, and optical fiber is subjected to the problems such as impact of other adjection, and structure and the technique of simplifying flowmeter.
(2) technical scheme
For achieving the above object, the invention provides a kind of force-measuring type optical fibre flowmeter, this force-measuring type optical fibre flowmeter comprises: the shell 10 that this force-measuring type optical fibre flowmeter and tested pipeline is affixed; Be installed on shell 10 sidewall outsides and two ends all with the measuring tube 20 of shell 10 inner sealing UNICOMs; Be installed on measuring tube 20 inside produce distortion under the pressure of fluid dynamometry diaphragm 30; Be installed on the fixed beam 50 of measuring tube 20 inner fixed fiber gratings 40, and fixed beam 50 is arranged at dynamometry diaphragm 30 and meets a side to fluid flow direction; And the fiber grating 40 that is fixed in the power of measuring the Fluid Flow in A generation between fixed beam 50 and the dynamometry diaphragm 30.
In the such scheme, described shell 10 is the cylindrical of hollow, and its sidewall has two holes, and the two ends of measuring tube 20 are by these two holes and shell 10 inner sealing UNICOMs.
In the such scheme, the end that described measuring tube 20 enters at fluid has a fair water fin 60, and a certain proportion of fluid enters measuring tube 20 in the tested pipeline under the water conservancy diversion of this fair water fin 60.
In the such scheme, described dynamometry diaphragm 30 is circular, is fixed in the inwall of measuring tube 20 by at least one root 31, and between the inwall of dynamometry diaphragm 30 and measuring tube 20 slit that allows fluid pass through is arranged.
In the such scheme, the rigidity of described fixed beam 50 is greater than the rigidity of dynamometry diaphragm 30, and the sectional area of fixed beam 50 in measuring tube 20 is less than the sectional area of dynamometry diaphragm 30.
In the such scheme, described fixed beam 50 is installed on this measuring tube 20 inside, and there are a center pit 51 in the central authorities of this fixed beam 50, and described fiber grating 40 is affixed with this fixed beam 50 by this center pit 51.
In the such scheme, an end of described fiber grating 40 is fixed in the center 32 of dynamometry diaphragm 30, and the other end passes successively the center pit 51 of this fixed beam 50 and the fairlead on this measuring tube 20 sidewalls and drawn.
(3) beneficial effect
Can find out that from technique scheme the present invention has following beneficial effect:
1, this force-measuring type optical fibre flowmeter provided by the invention, the mode that adopts the measuring tube outside former pipeline to measure has reduced to greatest extent on the flow of former pipeline and the impact in flow field.
2, this force-measuring type optical fibre flowmeter provided by the invention, the method by installing optical fibres grating between fixed beam 50 and dynamometry diaphragm 30 makes fiber grating be parallel to direction of flow, has reduced the adjection of fluid to optical fiber.
3, this force-measuring type optical fibre flowmeter provided by the invention, by measuring tube is set outside former pipeline and between fixed beam 50 and dynamometry diaphragm 30 method of installing optical fibres grating, simplified sensor construction and technique.
Description of drawings
Fig. 1 is the synoptic diagram of force-measuring type optical fibre flowmeter provided by the invention;
Fig. 2 is the synoptic diagram of the dynamometry diaphragm of force-measuring type optical fibre flowmeter provided by the invention;
Fig. 3 is the synoptic diagram of the fixed beam of force-measuring type optical fibre flowmeter provided by the invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.
Please refer to Fig. 1-Fig. 3, Fig. 1 is the synoptic diagram of force-measuring type optical fibre flowmeter provided by the invention; Fig. 2 is the synoptic diagram of the dynamometry diaphragm of force-measuring type optical fibre flowmeter provided by the invention; Fig. 3 is the synoptic diagram of the fixed beam of force-measuring type optical fibre flowmeter provided by the invention.
This force-measuring type optical fibre flowmeter comprises: the shell 10 that this force-measuring type optical fibre flowmeter and tested pipeline is affixed; Be installed on shell 10 sidewall outsides and two ends all with the measuring tube 20 of shell 10 inner sealing UNICOMs; Be installed on measuring tube 20 inside produce distortion under the pressure of fluid dynamometry diaphragm 30; Be installed on the fixed beam 50 of measuring tube 20 inner fixed fiber gratings 40, and fixed beam 50 is arranged at dynamometry diaphragm 30 and meets a side to fluid flow direction; And the fiber grating 40 that is fixed in the power of measuring the Fluid Flow in A generation between fixed beam 50 and the dynamometry diaphragm 30.
Wherein, shell 10 is the cylindrical of hollow, and its sidewall has two holes, and the two ends of measuring tube 20 are by these two holes and shell 10 inner sealing UNICOMs.The end that measuring tube 20 enters at fluid has a fair water fin 60, and a certain proportion of fluid enters measuring tube 20 in the tested pipeline under the water conservancy diversion of this fair water fin 60.Dynamometry diaphragm 30 is circular, is fixed in the inwall of measuring tube 20 by at least one root 31, and between the inwall of dynamometry diaphragm 30 and measuring tube 20 slit that allows fluid pass through is arranged.The rigidity of fixed beam 50 is greater than the rigidity of dynamometry diaphragm 30.Fixed beam 50 is installed on this measuring tube 20 inside, and there are a center pit 51 in the central authorities of this fixed beam 50, and described fiber grating 40 is affixed with this fixed beam 50 by this center pit 51.One end of fiber grating 40 is fixed in the center 32 of dynamometry diaphragm 30, and the other end passes successively the center pit 51 of this fixed beam 50 and the fairlead on this measuring tube 20 sidewalls and drawn.
The principle of work of force-measuring type optical fibre flowmeter provided by the invention is that with reference to figure 1, Fig. 2 and Fig. 3, when fluid flowed in shell 10, a part of fluid entered measuring tube 20.The sectional area of fixed beam 50 in measuring tube 20 is much smaller than the sectional area of dynamometry diaphragm 30, and the rigidity of fixed beam 50 is much larger than the rigidity of dynamometry diaphragm 30, therefore when fluid flows through in measuring tube 20, distance between the center 51 of fixed beam 50 and the center 32 of dynamometry diaphragm 30 can change, thereby cause that the fiber grating 40 during being fixed on produces strain, changing by the output wavelength of measuring grating 40 to obtain uninterrupted.
Need to prove that for wavelength-modulated type Fibre Optical Sensor, sensitive element is not limited to fiber grating, namely fiber grating 40 can be replaced by other device and obtain same effect, other device such as fiber laser, long-period gratings, chirp grating etc.
Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.