RU2511705C2 - Turbine flowmeter - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: turbine flowmeter contains a case with a measuring channel, in which between two fairings, respectively the jet-guiding device and the jet straightener, with possibility of axial moving and rotation there is a turbine, and also a unit of signal pickup. On the hub of the turbine there are blades, on which the circular shedding bar is fixed with blades on its outer side and the blades fixed on inside of the mentioned circular body. For providing hydrodynamic equilibration of a turbine at the end of the hub at the opposite side to the inlet there is a circular collar, in which there are longitudinal through channels located against blades, on which the circular shedding bar is fixed. The height of the blades fixed on inside of the shedding bar, is less or is equal to distance between the shedding bar and the circular collar.

EFFECT: ensuring reliability of hydrodynamic equilibration of a turbine in a wide range of measured expenses, also at maximum flow rates, expansion of a range of measurements, sensitivity increase on small flow rates, increase of accuracy of measurements, increase in a resource of work, decrease in pressure losses, simplification of manufacturing techniques of a turbine together with the device for its hydrodynamic equilibration.

3 cl, 2 dwg

Description

The invention relates to measuring equipment and can be used, in particular, for measuring the flow rate of liquids and gases,

Known turbine flowmeter (AS USSR No. 611113, class G01F 1/12, 06/15/78), comprising a housing with a measuring channel; inlet cowl with a device to reduce the influence of viscosity of the medium; output fairing; a turbine, on the blades of which a profiled ring with an outer surface expanding in the flow direction is installed on the blades of the flow, forming annular gaps with the hub of the turbine and with an inlet cowl, and an annular protrusion is made on the wall of the measuring channel opposite the profiled ring.

The design of such a flow meter does not provide complete hydrodynamic balancing of the turbine over the entire flow range, has increased pressure losses due to a decrease in the bore in the region of the annular protrusion and the profiled ring. The operational disadvantage is the small gaps between the profiled ring and the inlet cowl.

Known turbine flowmeter (patent for floor. Mod. RU No. 93527 Ul G01F 1/10 dated 04/27/2010, No. 12), comprising a housing with a measuring channel, in which are arranged in series: a flow guide made in the form of ribs located on the front fairing ; a turbine mounted with the possibility of axial movement and rotation, which is a hub with a hydrodynamic balancing device in the form of one or two end conical beads with blades fixed to it and an annular resistance body; rear cowl jet straightener; a converter for rotating the turbine into an output signal. In this flow meter, a recess (for example, an annular shape) is made in the end part of the ribs of the flow guide apparatus from the turbine side, the inner diameter of which is smaller than the inner diameter of the annular resistance body, and the outer diameter is larger than the outer diameter of the annular resistance body, while the screw pitch of the turbine blades located between the annular body of resistance and the hub may be more or less than the screw pitch of the blades of the turbine on the outer side of the annular body of resistance, and the length of the annular a resistance greater axial length of the turbine blades.

Such a turbine has a high hydraulic resistance, which has a negative effect on its hydrodynamic balancing and metrological characteristics.

As a prototype, a turbine flowmeter was selected (patent for floor mod. RU No. 113351 U1 G01F 1/10 dated 02/10/2012, No. 4), comprising a housing with a measuring channel, in which, in sequence along the flow, are placed: a flow guide made in the form ribs located on the front fairing; a turbine mounted for axial movement and rotation, comprising a hub with blades connected along the outer perimeter with an annular flow body to form an inner blade rim of said annular flow body, which also has an external blade rim; a hydrodynamic balancing device in the form of one or two conical beads formed at the ends of the hub; rear cowl jet straightener; a converter for rotating the turbine into an output signal. In this case, the annular flow body together with the external blade ring is made with axial displacement with respect to the internal blade ring. Also, the outer blade ring can be made with axial displacement with respect to the inner blade ring in the direction of the front or rear fairing.

In this design, along with the fact that the turbine has a high hydraulic resistance and has a negative effect on its hydrodynamic balancing and metrological characteristics, complex technology is required for the manufacture of the turbine together with shoulders to ensure hydrodynamic balancing.

The present invention is aimed at achieving a technical result, ensuring the reliability of hydrodynamic balancing of the turbine in a wide range of measured flow rates, including at maximum flow rates, expanding the measurement range, increasing sensitivity at low flow rates, increasing measurement accuracy, increasing the operating life, reducing pressure losses, simplifying technologies for manufacturing a turbine together with a device for its hydrodynamic balancing.

The specified technical result is achieved in a turbine flow meter, comprising a housing with a measuring channel, in which are sequentially placed: flow guide apparatus made in the form of ribs located on the front fairing; a turbine mounted with the possibility of axial movement and rotation, consisting of a hub with blades on which an annular flow body is fixed with blades on its outer side and blades fixed on its inner side; a hydrodynamic balancing device in the form of an annular collar made from the end face of the hub opposite the flow inlet, with a diameter larger than the diameter of the hub with longitudinal through channels passing through said annular collar; rear cowl jet straightener; a converter for rotating the turbine into an output signal. Moreover, the height of the blades mounted on the inner side of the annular flow body is less than or equal to the distance between the annular flow body and the annular flange. In the annular flange made longitudinal through channels. The longitudinal through channels in the annular flange are located against the blades on which the annular flow body is fixed.

The figure 1 schematically shows the device of the proposed turbine flowmeter.

The figure 2 shows the device of the turbine with an annular collar and through channels passing through it.

The proposed turbine flow meter (figure 1) comprises a housing 1 with a measuring channel 2, in which are located: a flow guide apparatus in the form of ribs 3 with a front cowl 4; the turbine (figure 2), mounted with axial movement and rotation, consists of a hub 5 with blades 6 on which an annular flow body 7 is fixed with blades 8 on its outer side and blades 9 of height A fixed on its inner side, device for hydrodynamic balancing of the turbine in the form of an annular collar 10 with longitudinal through channels 11; jet straightener with a rear fairing 12; a converter for rotating the turbine into an output signal 13.

Turbine flowmeter operates as follows. When the measured medium moves along the channel 2 through the jetting apparatus 3, a reduced static pressure is created in the gap between the front fairing 4 and the hub 5 of the turbine. The end part of the hub of the turbine and the annular flange from the side of the rear fairing is affected by dynamic pressure. The result is a force acting on the turbine against the flow. The turbine begins to move towards the front fairing. When the turbine moves against the flow, the hydrodynamic resistance increases and the force acting on the turbine in the flow increases. This increases the gap between the end face of the hub and the rear fairing and part of the flow passes through the channels in the annular flange. All this leads to a decrease in the force of the dynamic pressure acting on the turbine against the flow. The forces acting on the turbine upstream and downstream are balanced and, with further flow, the turbine remains in a balanced state.

Due to the fact that the blades mounted on the inner side of the annular flow body are made of height A, a gap is formed between the blades and the hub, which reduces hydraulic resistance and, together with the presence of through channels in the annular collar, leads to a decrease in the pressure force on the turbine. The flow passing through the through longitudinal channels in the annular flange, allows to provide optimal conditions for hydrodynamic balancing of the turbine.

An annular flow body in a turbine divides the flow into two annular flows, which, together with the presence of blades fixed on the inner side of the annular flow body, and through longitudinal channels in the annular flange, makes it possible to form an optimal diagram of the distribution of flow velocities acting on the turbine blades and increase the degree turbulence. All this allows you to increase sensitivity and expand the measurement range in the direction of low costs.

The specified technical solution allows to obtain a turbine flowmeter with a hydrodynamically balanced turbine in a wide range of flow rates, expand the measurement range, increase sensitivity, reduce the hydraulic resistance of the turbine, increase the service life, simplify the technology of manufacturing the turbine.

Claims (3)

1. A turbine flowmeter comprising a housing with a measuring channel, in which are sequentially placed: a flow directing device made in the form of ribs located on the front fairing; a turbine mounted with the possibility of axial movement and rotation, consisting of a hub with blades on which an annular flow body is fixed with blades on its outer side and blades fixed on its inner side; a hydrodynamic balancing device in the form of an annular collar made from the end face of the hub opposite the flow inlet, with a diameter greater than the diameter of the hub, with through longitudinal channels passing through said collar; rear cowl jet straightener; a converter for rotating the turbine into an output signal, characterized in that the height of the blades mounted on the inner side of the annular flow body is less than or equal to the distance between the annular flow body and the annular bead. 2. The turbine flowmeter according to claim 1, characterized in that the longitudinal through channels are made in the annular flange. 3. The turbine flowmeter according to claim 2, characterized in that the longitudinal through channels in the annular flange are located against the blades on which the annular flow body is fixed.

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