JPS6029695Y2 - Flow rate/flow rate detection device - Google Patents

Description

[Detailed description of the invention] The present invention is a flow velocity sensor that detects the flow velocity or flow rate of fluid in a flow path.
The present invention relates to a flow rate detection device, and particularly relates to a flow rate/flow rate detection device that detects the flow rate or flow rate of a fluid from the generation frequency of Karman vortices.

When an object that resists the flow of the fluid is provided in the passage of the fluid to be measured, a Karman vortex street is generated under certain conditions.

The generation frequency of this Karman vortex is proportional to the fluid flow rate within a certain Reynolds number range, and therefore, by detecting the number of stations occurring per unit time, the fluid flow rate and further the flow rate can be measured.

Incidentally, the occurrence of a vortex can be detected through changes in the pressure within the fluid or changes in the pressure within the fluid caused by the vortex, but in this case, it is necessary to reliably identify and detect changes in the state of the fluid due to individual vortices. be.

Conventionally, vibrations in one direction of the vortex generator itself or vibrations of a diaphragm provided in the vicinity of the vortex generator, which occur in response to changes in fluid pressure due to the vortex row generated by the vortex generator, have been suppressed by capacitance, electrical resistance, Detection devices that detect periodic changes in the direction of reflection of waves, etc. are known.

However, the above-mentioned known detection devices have the disadvantages that they tend to malfunction due to other vibrations, have complicated detection circuits, and are limited by the chemical properties or temperature of the fluid to be measured. .

In order to eliminate the above drawbacks, one end of the vortex detector is fixed to the main body, and the other end is fixed to a stress transmission member fixed to the main body. A flow velocity/flow rate detection device has also been developed that is configured to transmit the stress to a stress detection element such as a piezoelectric element via a stress transmission member.

However, in this type of device, in order to reliably transmit the stress transmitted to the stress transmission member to the stress detection element, the stress detection element must be fixed to the stress transmission member, making it difficult to remove the stress detection element for inspection and replacement. In addition, in order to transmit the stress generated in the vortex detector to the stress detection element without dissipating it, the pressure transmission member must be made relatively thin, and as a result, the heat between the stress detection element and the fluid to be measured is reduced. Insulation cannot always be sufficiently affected. Therefore, when trying to detect the flow rate/flow rate of high-temperature fluid, it is not only difficult to avoid temperature dependence of the detection output, but also the sensitivity of the stress detection element in a relatively short period of time. There is also a risk of deterioration or damage.

The present invention was developed in view of the above points, and its purpose is to provide a flow velocity/flow rate detection device that is almost unaffected by vibrations and can detect flow velocity or flow rate with relatively high sensitivity even in high-temperature fluids. It is about providing.

Next, a specific example of the present invention will be explained based on the drawings.

In the figure, reference numeral 1 denotes a vortex generator/vortex detector which is fixed at one end 4 via a flange 5 to a main body 3 through which a fluid 2 to be measured flows.

Note that the vortex generator may be formed of a separate member from the vortex detector.

The vortex generator 1 passes through the body 3 in a direction perpendicular to the flow direction A of the fluid 2 and has a free end 8 in a space 7 in a projection 6 provided above the body 3.

This free end 8 is provided with a spherical recess 9 into which the spherical end 10 of the displacement mounting member 11 just engages.

The displacement extracting member 11 has a daruma-shaped twin sphere 1 together with an end portion 10.
Another spherical protrusion 13 forming the piston 2 is engaged with a spherical recess 16 of the piston 15 as a sealing member, which is inserted into the cylinder bore 14 in the projection 6 .

15a is a seal ring.

The protrusion 13 has a through hole 15b provided in the piston 15.
An arm 17 extends through the arm 17, and a rotating ellipsoidal pushing portion 18 serving as a detection end is formed at the extending end of the arm 17.

The engaging portion 16a between the spherical protrusion 13 and the spherical recess 16 not only supports the rotational displacement of the member 11, but also serves as a seal between the inside and outside of the tube.

Fluid 2 in the pipe is sealed by the engaging portion 16a and the seal ring 15a
is sealed, and there is no possibility that the fluid 2 will enter the pushing part 18 side.

The protrusion 6 of the main body 3 is provided with a lid 19 having a transverse hole 20 .

The horizontal hole 20 and the cylinder hole 14 communicate with each other through a communication hole 21 provided in the lid 19.
It penetrates through and projects into the hole 20.

A piston spring 22 is installed in the hole 14, and the spring 22 uses the lower surface 23 of the lid 19 as a spring holder to urge the piston 15 in the D direction by its extension force.

Therefore, due to the Karman vortex generated in the fluid to be measured 2 around the end 4 fixed to the flange 5, the vortex detector 1
When the engaging end portion 10 of the member 11 is rotated back and forth in the directions B and C, the engaging end 10 of the member 11 is rotated in the directions B and C using the center 24 of the spherical protrusion 13 as the S' fulcrum, in other words, with the retaining surface 16a as the supporting surface. C
It is reciprocated and rotated in the direction.

As a result, the pushing portion 18 of the member 11 is pivoted back and forth in the C direction and the B direction with the center 24 as a fulcrum S'.

The magnitude of the displacement of the pushing part 18 or the force transmitted to the pushing part 18 can be adjusted by adjusting the length of the arm 17, and when detecting displacement, it is made longer than the length of the twin method. and is formed relatively short when detecting force.

Since the spring 22 always presses the twin method 12 against the detection object 1 in the D direction via the piston 15, the end 8 of the detection object 1 and the end 10 of the member 11 come into contact and the piston 15 and the protrusion. Abutment with part 13 can be maintained at all times.

In order to ensure the transmission of the above-mentioned displacement (or force), it is desirable to form the piston 15 relatively long in the vertical direction and to form the outer surface of the piston 15 and the cylinder hole 14 with precision finishing. In some cases, surface 16 may be provided with an O-ring.

Furthermore, since the spring 22 is provided between the main body 3 and the vortex detector 1, the spring 22 absorbs the difference in thermal expansion between the vortex detector 1 and the main body 3, regardless of whether the temperature of the fluid to be measured is low or high. This can be compensated for by the expansion or contraction of the vortex detector 1, and there is little possibility that distortion or the like will occur in the vortex detector 1.

Inside the hole 20 there are pads 25 and 26 symmetrically on the left and right sides of the pusher 18.
, displacement detector 27.28, spring receiver 29°30, spring 31
, 32, and set screws 33, 34 are provided.

The set screws 33 and 34 are removably engaged with threaded portions 35 and 36 provided on both sides of the hole 20, respectively, and the spring 31
．． It functions as a spring holder for 32.

Note that even when the pressure fluid 2 is flowing inside the pipe, the screw 33
．． By loosening 34, the detectors 27 and 28 can be
It can be attached and detached from the upper hole 37.38 of the detector 2.
7.28 maintenance can be easily performed.

The spring receiver 29, the detector 27, and the stopper 25 are urged in the direction B by the extension force of the spring 31 supported at one end by the screw 33, and the extension force of the spring 32 forces the spring receiver 30.
, the detector 28, and the stopper 26 are biased in the C direction.

As a result, the pads 25 and 26 are always in contact with the pusher 18.

The detectors 27 and 28 are formed by strain-type load detecting means such as piezoelectric elements or strain gauges, and detect B and C of the pushing portion 18 that is generated with the generation of the Karman vortex 2a.
The displacement or biasing force in the direction is output as an electrical signal.

When the end portion 8 of the vortex detector 1 receives a force to be displaced in the B direction, the pushing portion 18 receives a force to be displaced in the C direction (
For example, the output voltage of the piezoelectric element 27 increases and the output power of the piezoelectric element 28 decreases.

On the other hand, when the end portion 8 of the vortex detector 1 receives a force to be displaced in the C direction, the output voltage of the piezoelectric element 27 decreases and the output voltage of the piezoelectric element 28 increases.

Therefore, by extracting the difference voltage between the output voltage of the piezoelectric element 27 and the output voltage of the piezoelectric element 28, the detection signal can be increased and extracted.

In addition, the outputs of the piezoelectric elements 27 and 28 do not change due to the displacement of the vortex detector 1 in the direction perpendicular to the plane of the drawing due to pressure pulsations of the fluid 2, in other words, the displacement of the pusher 18 in the direction perpendicular to the plane of the drawing.

Therefore, in the flow rate/flow rate detection device 39 of the present invention, an output signal having a period corresponding to the generation period of the Karman vortex 2a can be obtained with less influence from noise other than the Karman vortex.

Furthermore, the pusher 18 to the detector 27.28 are connected to the piston 15.
Since the pushing part 18 and the detectors 27 and 28 are sealed by
is less likely to be contaminated by foreign matter such as sludge in the fluid 2, and is less likely to reduce detection sensitivity.
Measurement of flow velocity and flow rate of high temperature fluids, steam, etc. can also be performed.

Money 25.26, detector 27.2B, spring receiver 29,30
, instead of using springs 31, 32 and screws 33, 34,
In order to detect the cycle of reciprocating displacement of the output end 18 of the displacement extraction member 11 in the left and right directions (C and B directions) in the drawing, the period of capacitance change of a capacitor with the output end 18 as one electrode, a ferromagnetic material, etc. It may also be detected as a period of change in the inductance of the coil due to vibration of the extraction end 18, a period of change in the traveling direction of the light, or the like.

For example, in the vortex detector disclosed in Japanese Utility Model Application No. 53-159360, one end is supported by point contact or line contact and the other end is a free end. Since the body 1 is fixed at one end and engaged and supported at the other end, it is not only hardly affected by external vibrations, but also the displacement can be extracted as desired by the displacement extraction member, making signal detection easy. becomes.

As described above, according to the present invention, the vortex detector of the flow velocity/flow rate detection device is fixed to the main body at one end and engaged with the displacement extraction member at the other end, so that the vortex detector vibrates due to external vibration etc. Since the displacement can be expanded and extracted using the displacement extraction member, the detection sensitivity can be increased. In addition, since the detection end of the displacement extraction member penetrates the seal member and protrudes outside the main body, the The flow rate and flow rate can be detected regardless of the temperature and pressure of the fluid, and there is little risk of deterioration in detection sensitivity due to contamination with the fluid to be measured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a flow velocity/flow rate detection device according to a preferred embodiment of the present invention, FIG. 2 is a sectional view taken along line XX' of the flow velocity/flow rate detection device of FIG. 1, and FIG. FIG. 3 is a partial cross-sectional view of the flow velocity/flow rate detection device. 1... Vortex generator, vortex detector, 2... Fluid to be measured, 3... Main body, 4, 8... End, 11... ...Displacement extraction member, 15... Zeston.

Claims (1)

[Scope of utility model registration request] a vortex generator, a vortex detector having one end fixed to the main body and a free end displaced by the vortex generated by the vortex generator; one end engaged with the free end; 1. A flow velocity/flow rate detection device comprising: a displacement extraction member that penetrates a seal member defining a main body and has a detection end protruding beyond the main body, and is displaced using the penetration portion as a fulcrum.