A kind of double C-type tube coriodis mass flow meter
Technical field
The present invention relates to a kind of coriolis mass flowmeters.
Background technology
As everyone knows, caused Coriolis force was determined its quality when the work of coriolis mass flowmeters was flowed through responsive pipe based on test fluid, when just vibrating on the vertical direction of being divided fluid to flow by the responsive Guan Zaiyu of two end supports, the Coriolis force that is applied on the responsive pipe is directly proportional with the quality of the pipe fluid of flowing through.
The shape that constitutes the responsive pipe of coriolis mass flowmeters is miscellaneous, and in the existing flowmeter, more typical responsive tube shape can be summed up as three kinds: bend pipe, straight tube, bow shape tube.
Fig. 8 is the structural representation of the crooked responsive tube coriodis mass flow meter of common two parallel U-shapes, the responsive pipe 1 and 2 of the U type of two parallel installations, in the centre of their sweep driver element 15 is housed, this driver element 15 is made of a coil and a magnet.In addition, be equipped with two respectively by a coil and the signal transducer that magnet constituted 16 and 17 with driver element 15 both sides symmetric positions, when driver element 15 energisings, when making the stressed generation displacement of two responsive pipes, signal transducer 16 and 17 coil then produce displacement signal, this signal feedback just makes responsive pipe be operated in resonant condition to driver element; And two phase difference between signals that signalling means produces are directly proportional with the Coriolis force that is detected, and also promptly are directly proportional with institute fluid measured quality.
Treat that fluid measured enters shunting house steward 37 by entrance point flange 18, change 90 ° through baffle plate 38, be divided into two through isocon again and enter in the responsive pipe 1 and 2, this two fluid streams flows through responsive pipe 1 and at 2 o'clock, oppositely entering chorista again unites two into one, 90 ° of house steward's transfers, flow out in the external pipe by discharge flange 19.In this structure, because responsive pipe is in resonant condition, its driving frequency is than higher, and is not subject to fluid state and extraneous vibration and influence of temperature variation.
But, this coriolis mass flowmeters, because the responsive pipe of two U type is installed with always tube body is vertical, for guaranteeing certain vibration frequency, U type pipe just must have required length on the one hand; On the other hand, in order to reduce the loss of energy of vibration, or strengthen the rigidity of total tube body, its total tube body must have enough wall thickness and comparatively thick flowmeter physical dimension.
The responsive pipe of straight tube shape coriolis mass flowmeters is to arrange along the axis direction of input and output pipe, and its two ends are supported on the pedestal or in the outer tube.The middle part of responsive pipe is provided with the signal transducer of driver element and the equidistant installation in driver element both sides.When driver element work, make when producing displacement on the perpendicular direction of its axis of responsive Guan Zaiyu, sensor also its change in displacement of sensing feeds back to driver element again, makes responsive pipe be operated in resonant condition.The quality that can detect fluid from the displacement or the phase differential of two sensors.Linear tube Coriolis mass flowmeter is relatively more responsive to temperature, because responsive pipe is supported in stage body or the outer tube, when the temperature of measured fluid changes, the temperature of responsive pipe is very fast to be changed with fluid temperature (F.T.), but the temperature of pedestal or outer tube then postpones to change, and like this, makes inevitably and produces the inconsistent of expansion and contraction between responsive pipe and pedestal or the outer tube, also just make responsive pipe produce stress, and then can cause the rigidity and the change of resonance frequency of responsive pipe.For overcoming this problem, structurally linear tube Coriolis mass flowmeter need consider to adjust the flexible member compensation mechanism of stress.
Fig. 9 is a bow shape tube coriolis mass flowmeters structural representation.This structure has been alleviated stress dissipation problem to a certain extent, has compensated the shortcoming of the easy temperature influence of straight pipe type, but imports and exports the shape more complicated of house steward and branch fluid and resistance to compression housing, has increased the manufacture difficulty and the weight of instrument.
Make a general survey of the existing relative merits of above-mentioned dissimilar coriolis mass flowmeters, can find out very clearly that wherein topmost problem is loss and two aspects of stress elimination of responsive tube vibration energy, certainly, the problem such as easy and reduced volume, weight reduction that also has technology in addition.
Summary of the invention
The objective of the invention is to propose a kind of coriolis mass flowmeters that constitutes by two responsive pipes of parallel C type, it is not subjected to the internal stress and the responsive influence of managing the deformational stress that produces in the forming process of external vibration, mounting condition, responsive pipe, can reduce the loss of energy of vibration, the measuring accuracy of flowmeter that improves the quality, and can reduce the physical dimension and the weight of mass flowmeter.
The technical scheme that realizes the object of the invention is: a kind of double C-type tube coriodis mass flow meter, the responsive pipe of C type that comprises two parallel installations, two responsive pipes are fixed by two fixed heads respectively, and be welded on total tube body, two responsive pipes of C type are except 4 ends and total tube body are rigidly connected, be in free state fully, two fixed heads are separately positioned on the root of close two responsive pipes, in end of responsive pipe or other temperature sensor is equipped with at position that vibration characteristics does not exert an influence---thermistor, total tube body is the physical construction of a complete reverse symmetry of input and output, just fluid flows into total input port, flows out from two bifurcations with just being divided into two then; Conversely, fluid flows into from two bifurcations, unites two into one then to flow out from total delivery outlet, and its pipe shape is reverse symmetry fully, and the house steward of total tube body and take-off pipe size are a bit larger tham the size of the responsive pipe of measured flux, and crooked and meet the face place and seamlessly transit.
According to distance between input, delivery trunk and the take-off pipe and different with the Outer Tube connected mode, two kinds of embodiments are arranged:
First kind is that distance between input, delivery trunk and the take-off pipe is longer, and they directly have two external flanges.
Second kind is that distance between input, delivery trunk and the take-off pipe is shorter, and they can be not flanged, with external pipe can be with being threaded.
Description of drawings
Fig. 1 is a double C-type tube coriodis mass flow meter structural representation of the present invention.
Fig. 2 is the A-A cut-open view of Fig. 1.
Fig. 3 is the B-B cut-open view of Fig. 1.
Fig. 4 is total tube body of the present invention and the local structure for amplifying synoptic diagram that divides the fluid gateway.
Fig. 5 is the A-A cut-open view of Fig. 4.
Fig. 6 is the B-B cut-open view of Fig. 4.
Fig. 7 is the C-C cut-open view of Fig. 4.
Fig. 8 is the structural representation of common common two parallel U-shape tube coriodis mass flow meters.
Fig. 9 is the structural representation of two parallel bow shape tube coriolis mass flowmeters.
Figure 10 is the structural representation of first embodiment of the invention.
Figure 11 is the structural representation of second embodiment of the invention.
Embodiment
Coriolis mass flowmeters of the present invention, as shown in Figure 1, it comprises two responsive pipes 1 and 2 of parallel C type, detected fluid is divided into two after entering flowmeter from body house steward 25 input ports 5, flow into responsive pipe 1 and 2, in the outlet inflow body of sensitivity pipe 1 and 2, unite two into one then, flow to external pipe by house steward's delivery outlet 6 through flange 18, in sensitivity pipe 1 and 2 stage casings, driver element 15 is housed, two responsive pipe resonance during work, symmetrical mounting detects and the proportional phase signal of Coriolis force at the displacement signal device 16 and 17 of sensitivity pipe 1 and 2 circular arc center sections.
Coriolis mass flowmeters of the present invention comprises input, the delivery trunk body 25 of an approximate rigid body, and as seen from Figure 4, it is a structurally member of reverse symmetry.As Fig. 5, shown in Figure 7, input and delivery trunk 5 and 6, after circular arc is turned, be divided into symmetrically separately again two pairs of gateways 7 with 8 and 9 with 10 complete corresponding identical members, this preparation and mechanical processing technique to the member blank all is eaily.
Coriolis mass flowmeters of the present invention is equipped with temperature sensor at a responsive pipe with the root that total tube body is connected---thermistor 3, so that detect the online temperature of responsive pipe and detected fluid, and this quality flowmeter compensated by influence of temperature change or revise.
As shown in Figure 1 and Figure 2, be used to determine that the fixed head 27 and 28 of vibration nodal point is set at the root of the responsive pipe 1 and 2 of close C type.The effect of fixed head, at first, be to keep responsive pipe 1 with 2 parallel; Secondly, when responsive pipe was driven, they the fundamental frequency of oscillating movement along the determining positions of responsive tube's axis, just changed the position of fixed head, can adjust the resonance frequency of responsive pipe within the specific limits.As can be seen, in the coriolis mass flowmeters structure of the responsive pipe of double C-type of the present invention, the straight-line segment of responsive pipe root when vibration is done twisting motion, and then does the compound motion that promptly reverses bending at circular arc portion.This movement characteristic is favourable to alleviating vibrating tube fatigue.
In addition, liftoff being connected on total tube body of four end low coverages of the responsive pipe of two C types if when a total tube body treated as rigid body, just the vibration of two responsive pipes can not cause distortion at its root, just do not have the loss of vibrational energy yet; Simultaneously, two responsive pipes can not cause internal stress yet, thereby have guaranteed the measuring accuracy of mass flowmeter, are not installed again and the influence of environmental baseline.
As shown in Figure 3, driver element 15 and displacement transducer 16 and 17 are between the responsive pipe of two C types, and two responsive pipes 1 and 2 are fixed by fixed head 27 and 28, and be welded on total tube body again.
Driver element 15 is made of a coil and a magnet, its coil is fixed on the responsive pipe 1 by fabricated section, magnet then is fixed on the responsive pipe 2 by fabricated section, and coil links to each other with outlet line 34 through flexible circuit conductor 12, and outlet line 34 is contained on the housing 32.The installation of displacement transducer 16 and 17 installation and driver element 15 is similar, just their magnet is fixed on the responsive pipe by fabricated section, the coil of sensor then is fixed on another responsive pipe, the output lead of coil is gone to flexible circuit conductor 12 output with driver element 15 along responsive pipe, or receives connection terminal on the housing 32 again to outlet line 34 with flexible circuit conductor 12. Displacement transducer 16 and 17 be configured in the middle of the circular arc of responsive pipe 1 and 2 be since the distance that they leave driver element 15 place center lines farthest, this to improve detect Coriolis force or with the sensitivity of the proportional phase signal of institute's measurement of discharge be best.
As shown in Figure 4, total tube body is the physical construction of a complete reverse symmetry of input and output, and just fluid flows into total input port, flows out from two bifurcations with just being divided into two then; Conversely, fluid flows into from two bifurcations, unites two into one then to flow out from total delivery outlet, and its pipe shape is reverse symmetry fully.In order to reduce the resistance of liquid energy, the surface at turning should be slick and sly everywhere, it is bigger that responsive relatively pipe diameter and measured flux house steward and branch's caliber should design, the rigidity that this also is convenient to adapt to the flowmeter remodeling of different ranges within the specific limits and strengthens total tube body; That is to say, when needs increase range, when changing the sensitivity pipe of large-size diameter, only need be to the interface section increased in size of take-off pipe, or the size that the connection end of responsive pipe changes the transition external member got final product, do not need to change the design of total tube body.
Figure 10 shows that first kind of embodiment of the coriolis flowmeter of the responsive pipe of double C-type that the present invention adopts, Figure 11 shows that second kind of embodiment of the coriolis flowmeter of the responsive pipe of double C-type that the present invention adopts.Its difference mainly is the difference of total tube body 25 structures, in other words, mainly be input, delivery trunk with take-off pipe between distance and different with the Outer Tube connected mode.Figure 10 represents to import, the distance between delivery trunk and the take-off pipe is longer, and they directly have external flange 18 and 19; Figure 11 then represents to import, the distance between delivery trunk and the take-off pipe is shorter, and they can be not flanged, with external pipe can be with being threaded.This scheme can allow the volume of mass flowmeter itself littler, is more convenient for the installation on some ad-hoc location.If input, delivery trunk are adopted relative thinner pipe with transition section between the external pipe, its rigidity is not very big, and this more helps the damping and the installation of coriolis mass flowmeters itself.
Indulge the above, can find out the present invention compared with prior art, have the following advantages:
1, in end of responsive pipe or other temperature sensor is equipped with at position that vibration characteristic does not exert an influence, it Responsive pipe makes the variation of responsive pipe temperature but sensing liquid is flowed through, so as to coriolis mass flowmeters because of variations in temperature institute The impact that causes certainty of measurement is revised or is compensated.
2, the present invention is by two responsive coriolis mass flowmeters that consist of of managing of parallel C type, two responsive pipe 4 Individual end very near-earth is rigidly connected with total tube body, makes the motion power of responsive pipe become endogenetic process, thereby reduces or eliminate Vibration can loss, be conducive to improve the measuring accuracy of coriolis mass flowmeters.
3, the responsive pipe of the double C-type of coriolis mass flowmeters of the present invention is except 4 ends and total tube body rigid connecting Outside connecing, be in free state fully, also just can not produce because of variations in temperature the impact of the distortional stress that expands with heat and contract with cold.
4, total tube body of coriolis mass flowmeters of the present invention with respect to the structure of other types it size very Little; In addition, also need not to require rigidity bigger, the compression shell that structure is special, if common housing, these characteristics Overall dimensions and the weight of mass flowmenter have been dwindled widely.
5, the house steward of total tube body of coriolis mass flowmeters of the present invention and branched pipe require size to be a bit larger tham tested The size of flow-sensitive pipe, and require crooked and the junction place seamlessly transits is in order to what slow down at house steward's body part fluid Flow velocity and kinetic equation loss also are convenient to necessary cleaning.