CN1057902A - Turbine rate-of flow transducer - Google Patents

Abstract

In the turbine rate-of flow transducer according to this invention making, each groove (10) of MEDIA FLOW axial force compensator (3) will be made like this, make the longitudinal axis of groove form the boundary in 7～20 ° angle (α), and this angle is with the summit of its summit facing to impeller (4) blade (13) pitch angle (γ) by the projection (11) on impeller (4) pivot center (12) plane and the pivot center of impeller (4).In the scope of the big bottom surface of compensator (3), what all the area of groove (10) xsects accounted for impeller (4) porch passes through 2～6% of area of section.

Description

Turbine rate-of flow transducer

This invention belongs to the machinery manufacturing industry scope, more specifically says, belongs to turbine rate-of flow transducer.

This invention is used at many industrial sectors, is optimal as oil, petroleum refining, chemical industry and other industrial sector to the flow measurement of degree of becoming sticky liquid.

Current, be used for the turbine meter of measuring media flow, have lower measuring accuracy and narrow measurement range, these problems are because the nonlinearity of flowmeter characteristic and susceptibility that viscosity is changed cause.This situation be because in the technological equipment that uses the turbine type flow transducer, the flow of flow media and viscosity change in roomy scope.Therefore, currently exist such problem, guarantee to have under the situation of wide variation scope, have precision than higher measuring media flow in the flow and the viscosity of medium.

Be widely known by the people be a kind of turbine rate-of flow transducer that contains cylindrical housings (JP, A, 52-25748).First rectifier of MEDIA FLOW is installed in turn, the compensator of MEDIA FLOW axial force, second rectifier of impeller and MEDIA FLOW along the flow direction of MEDIA FLOW in housing.Each rectifier of MEDIA FLOW is made as with housing and is positioned at same axis, facing to the radome fairing of the MEDIA FLOW flow direction, and radially is mounted with the floor that is fixed in the housing on radome fairing.The compensator of axial force is made into frustum-like shape, and acts on mutually with the end face of first radome fairing with the less bottom surface of truncated cone.On the side surface of axial force compensator, produce the groove that is parallel to bus equably along whole peripheries.Impeller is installed to such an extent that have same axis with housing, and can rotate in housing.On the housing wall in settling the impeller zone, the sensitive element of signal transmitter is housed, when placing each blade of impeller in turn facing to sensitive element, signal will take place in this sensitive element.

Above-described transducer can be measured the flow of the medium with various different viscosities.But, structurally implement to be used for the axial force compensator of this transducer like this, because groove is straight, so the turbulence level that can not guarantee to form even velocity figure and influence enough MEDIA FLOW of Reynolds critical number will reduce measuring accuracy like this, and measurement range is narrowed down, the self-adaptation district of impeller work originates in the Reynolds critical number, in the self-adaptation district, will reach the linearize of the static characteristics of conversion, reduce the influence that measured medium viscosity changes.

The basic task of this invention is a kind of turbine rate-of flow transducer of development, and structurally such design axial force compensator, when the flow of measured medium and viscosity changed in roomy scope, this structural design can guarantee than higher measuring accuracy.

Being proposed of task is to solve like this, turbine rate-of flow transducer contains cylindrical housings, first rectifier of MEDIA FLOW is installed in turn along the flow direction of MEDIA FLOW in housing, the compensator of MEDIA FLOW axial force, second rectifier of impeller and MEDIA FLOW, first rectifier is made as with housing and is positioned at same axis, flow to the radome fairing of placing facing to MEDIA FLOW, and the floor that is fixed in the housing is installed radially on radome fairing, the axial force compensator is made into frustum-like shape, this truncated cone acts on the end face of radome fairing mutually with its less bottom surface, and whole peripheries are produced groove equably in the side surface upper edge of compensator, impeller is installed to such an extent that have same axis with housing, and can rotate, second rectifier is settled to such an extent that relative plane perpendicular to the wheel rotation axis with first rectifier is symmetrical, and make similar in appearance to first rectifier, in addition, on the housing wall in settling the impeller zone, the sensitive element of signal transmitter is housed, when placing each blade of impeller in turn facing to sensitive element, signal will take place in this sensitive element, according to this invention, every groove of compensator will be made like this, make the longitudinal axis of groove form a boundary in 7～20 ° angle by the pivot center of projection on the wheel rotation axis plane and impeller, and this angle is with the summit of its summit facing to the impeller blade pitch angle, in the scope of the big bottom surface of compensator, all the area of groove xsects be the impeller eye place pass through 2～6% of area of section.

In order to reduce the frontal drag of impeller blade, the MEDIA FLOW that assurance is brought does not enter impeller with having impact, and the moment that reduces to lean against the viscous friction on the impeller previous section, it is suitable that the profile of the ingress edge of each blade of impeller is formed with two planes, the angle on two planes 2/3(90 °-γ) to (in 90 °-γ) the scope, the γ here is the pitch angle of the relative wheel rotation axis of impeller blade.

Utilize to the explanation of specific embodiment with to the detailed explanation this invention of quoting as proof of accompanying drawing below.

Fig. 1 represents the longitudinal profile according to the turbine rate-of flow transducer of this invention making;

Fig. 2 is the II-II section on Fig. 1.

Fig. 3 is the distribution sketch of groove on the compensator of MEDIA FLOW axial force.

The turbine rate-of flow transducer of being recommended contains cylindrical housings 1(Fig. 1), first rectifier 2 of MEDIA FLOW, the compensator 3 of axial force, second rectifier 5 of impeller 4 and MEDIA FLOW are installed in turn along the flow direction of MEDIA FLOW in housing.Each rectifier 2,5 of MEDIA FLOW is all correspondingly made becomes the radome fairing 6 and 7 that is positioned at same axis with housing 1, and the floor 8 and 9 that is fixed in the housing 1 radially is installed on radome fairing.Two radome fairings 6 and 7 are arranged symmetrically with the plane perpendicular to the pivot center of impeller 4.Impeller 4 is installed on the axle 4a in the housing 1, and an axle 4a is fixed in radome fairing 6 and 7 with its two ends.The compensator 3 of MEDIA FLOW axial force is made as frustum-like shape, and this truncated cone acts on the end face of rectifier 6 mutually with its less bottom surface.On the side surface of the compensator 3 of axial force, produce groove 10(Fig. 2 equably) along whole peripheries.Each groove 10 of compensator 3 will be made like this, make its longitudinal axis constitute boundaries in 7～20 ° angle α, and this angle is with the summit of its summit facing to the pitch angle γ of impeller 4 blades 13 at pivot center 4 by projection on the plane of impeller 4 pivot centers 12 11 and impeller 4.When α＜7 ° and α＞20 °, in the low discharge scope, because the influence that the flow of measured medium and viscosity change, the rectilinearity of turbine type flow transducer characteristic correspondingly becomes and worsens increasing side and reduce side, will cause the reduction of measuring accuracy like this.

In the scope of the big bottom surfaces of compensator 3, the cross-sectional area of all grooves 10 be impeller 4 porch pass through 2～6% of area of section.If all groove 10 cross-sectional areas make exceed account for impeller 4 porch pass through area of section 2～6% these scopes, can not guarantee that MEDIA FLOW speed has best redistribution in impeller 4 front and backs, because the effect of velocity contrast, the redistribution of MEDIA FLOW speed will influence the fluid dynamic equilibrium of medium, under the situation of passing through area of section 2% of area less than impeller 4 porch of whole groove 10 transversal section, effect by means of velocity contrast, impeller 4 will push radome fairing 7, and under greater than 6% situation, effect by means of velocity contrast, impeller 4 will push radome fairing 6, like this with the rectilinearity and the measuring accuracy of degradation characteristic.

The profile of the ingress edge of impeller 4 each blade 13 forms with two planes, the angle on two planes 2/3(90 °-γ) in the scope of (90-γ).Can reduce the frontal drag of blade 13 like this, the MEDIA FLOW that assurance is brought does not enter impeller 4 with having impact, and the moment that reduces to lean against the viscous friction of impeller 4 previous sections, because above each point, the rectilinearity of characteristic can improve, and in the low discharge scope, conversion coefficient k=(ω)/(Q) (ω-angular velocity that causes because of the measured medium viscosity change, the Q-flow) skew also can reduce, and the skew of conversion coefficient k is to influence measuring accuracy and measurement range.

In the low discharge scope, with angle greater than (90 °-γ) two profiles that the plane makes the ingress edge of each blade 13, can impel and the additional component velocity that involves occur, this component velocity that involves will produce the moment that stops impeller 4 to rotate, thereby reduce the rectilinearity of characteristic, and the measuring accuracy that reduces turbine rate-of flow transducer.According to the reason of design aspect, also be unsuitable with angle less than the profile that 2/3(90 °-γ) two planes make above-mentioned ingress edge, because the not significantly influence of rectilinearity to improving characteristic like this.

On the wall of the housing 1 in placing the zone of impeller 4 (Fig. 1), the sensitive element 14 of the signal transmitter that links together with calculation element 15 is installed.

The turbine rate-of flow transducer of being recommended carries out work in the following manner.

Enter the MEDIA FLOW of cylindrical housings 1, pass first rectifier 2 of MEDIA FLOW and the groove (Fig. 3) of axial force compensator 3, act on mutually, force impeller to rotate with the angular velocity that is directly proportional with the measured medium flow with the blade 13 of impeller 4.

Because the groove of making on the side surface of axial force compensator 3 10 tilts, the a fluid stream that passes the MEDIA FLOW of above-mentioned groove 10 has rotational motion, to impel like this and fluctuation velocity occur, improve the turbulence level of MEDIA FLOW, this turbulence level is with the tr pt of mobile layer laminar boundary layer to turbulent boundary layer, reduce the thickness in boundary layer, and the paragraph that has turbulent boundary layer that enlarges impeller 4 blades 13.So also can reduce the Reynolds critical number and enlarge the self-adaptation district that impeller 4 is worked, in the self-adaptation district, can reach the static characteristics linearize of conversion, and the influence that reduces the measured medium viscosity change, this variation is to influence measuring accuracy and measurement range.

At sensitive element 14(Fig. 1 facing to signal transmitter) when placing the blade 13 of impeller 4 in turn, generation is sent to the electric signal of calculation element 15.

The turbine rate-of flow transducer of being recommended of making according to this invention can significantly improve the measuring accuracy of rate-of flow.Because the unloading of the hydrodynamic force of impeller, this turbine rate-of flow transducer has the reliability that increases.In addition, above-mentioned turbine type transducer anufacturability is good, and maintenance and repair are easy.

Claims (2)

1, turbine rate-of flow transducer contains cylindrical housings (1), in housing, be mounted with first rectifier (2) of MEDIA FLOW in turn along the flow direction of MEDIA FLOW, the compensator of MEDIA FLOW axial force (3), second rectifier of impeller (4) and MEDIA FLOW, first rectifier is made into the radome fairing facing to the MEDIA FLOW flow direction that is positioned at same axis with housing (1), and the floor (8) that is fixed in the housing (1) is housed radially in the radome fairing upper edge, compensator (3) system is dressed up frustum-like shape, and truncated cone acts on mutually with the end face of its less bottom surface with radome fairing (6), whole peripheries are produced groove (10) equably in the side surface upper edge of radome fairing, impeller (4) is installed to such an extent that have same axis with housing (1), and can rotate, second rectifier (7) is settled to such an extent that relative plane perpendicular to impeller (4) pivot center (12) with first rectifier is symmetrical, and make similar in appearance to first rectifier, in addition, place the sensitive element (14) of signal transmitter on the wall of the housing (1) in impeller (4) zone is installed, when laying each blade (13) of impeller (4) in turn facing to sensitive element, signal will take place in this sensitive element, the characteristics of this turbine rate-of flow transducer are, each groove (10) of compensator (3) will be made like this, make the longitudinal axis of groove form a boundary in 7～20 ° angle (α) by the projection (11) on the plane of impeller (4) pivot center (12) and the pivot center (12) of impeller (4), and this angle is with the summit of its summit facing to the pitch angle (γ) of impeller (4) blade (13), in the scope of the big bottom surface of compensator (3), what all the cross-sectional area of grooves (10) accounted for impeller (4) porch passes through 2～6% of area of section.

2, according to claim 1, the characteristics of turbine transducer are, the profile of the ingress edge of each blade of impeller (4) (13) is formed by two planes, angle between two planes 2/3(90 °-γ) to (in 90 °-γ) the scope, the γ here is the pitch angle of impeller blade with respect to the wheel rotation axis.

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