JPS59107209A - Pickup for vortex street flowmeter - Google Patents

Abstract

PURPOSE:To transmit a signal with one optical fiber single line, by incorporating a vortex signal generation source using light in a vortex generating body. CONSTITUTION:A vortex generating body 2 is provided in a pipe. A vortex street flowmeter pickup consisting of piezoelectric elements 5 and 6, a light emitting element 7, a reflective mirror 8, a conical lens 9, and an optical fiber 10 is stored in the generating body 2. Karman's vortexes are generated in the left and the right of the generating body 2 by the flow of a fluid to vibrate the generating body 2. When the generating body 2 is vibrated, a voltage is generated in piezoelectric elements 5 and 6, and the light emitting element 7 emits light. The light emitted from the element 7 is condensed to the lens 9 by the reflective mirror 9 and is transmitted through the fiber 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection device that optically detects a vortex in a vortex flow needle using the fact that the Karman vortex generation frequency is proportional to the flow velocity.

Conventionally, vortex detection devices in vortex flow needles detect changes in physical quantities based on the generation of Karman vortices, but most of these changes in physical quantities are converted into electrical signals and transmitted remotely. For this reason, at least two pieces of transmission cotton are required.

In addition, optical detection means is an excellent means because it enables signal transmission with a high S/N ratio that is not affected by electrical noise during electrical signal transmission. Microbending losses, optical rotation of optical dielectrics, changes in interference fringes due to changes in optical path length, and changes in reflection scenery due to changes in vortex detection elements are well known.

However, since these methods rely on an external light source, they require expensive bundled fiber cables and require a large amount of demultiplexing, which increases transmission costs.

The present invention was made from an assembly point of view, and its purpose is to create the simplest vortex signal transmission system using a single optical fiber by incorporating an optical vortex signal generation source into a vortex generator. It is intended to provide a pickup for flow companies.

The gist of this is that in order to detect vibrations of a vortex generator installed in a pipe that forms a fluid flow path, a vortex generator pickup housed inside the vortex generator 2
A light emitting element that emits light by a voltage generated between the two piezoelectric elements when the vortex generating body vibrates is bonded between the two piezoelectric elements, a light condenser is attached to one end surface of the light emitting element, and a light emitting element is attached to one end surface of the light emitting element. A reflecting mirror is attached to an end face other than the above-mentioned joint surface except for the part where the above-mentioned condenser is attached.

Hereinafter, the features of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing one embodiment of a vortex generator in which a vortex pickup according to the present invention is housed;
Fig. 3 is a perspective view of the vortex generator in which the vortex pickup according to the present invention is housed; Fig. 4 is a perspective view of the vortex pickup according to the present invention; FIG. 3 is a perspective view showing another embodiment of the invention.

In FIGS. 1, 2, 3, and 4, 1 is a pipe having a flow passage whose cross section perpendicular to the axis is circular, 2 is a vortex generator installed in the pipe 1, and 3 is Karman vortex generated by the vortex generator 2, 5.6 is a piezoelectric element (4 is an insulating material that insulates and fixes the piezoelectric element 5.6 inside the vortex generator 2, and is preferably opaque) 7 is a light emitting element, 8
9 is a reflecting mirror, 9 is a conical lens, and 10 is an optical fiber.

Due to the flow of fluid, Karman vortices 3 are generated on the left and right sides of the vortex generator 2 installed in the pipe 1, and as a result, the liquid flowing from the upstream side of the vortex generator 2 flows into the vortex generator. 2, but the generation of the Karman vortex 3,
Due to the separation, the velocity components in the downstream tube axis of the vortex generator 2 and in the direction perpendicular to the vortex generator 2 alternate in direction.

Inside the vortex generator 2, a light emitting element 7 is bonded between two piezoelectric elements 5.6, which emits light when a voltage is generated between the piezoelectric elements 5.6 when the vortex generator 2 vibrates. In addition, a reflecting mirror 8 is attached to the end surface of the light emitting element 7 other than the bonded surface, and a conical lens 9 is provided to the end surface opposite to the end surface to which the reflecting mirror 8 is attached. A pickup for the flow company is housed.

Note that the mounting position of the reflecting mirror 8 is not limited to the end surface other than the bonding surface of the light emitting element 7 as described above, and as shown in FIG. The piezoelectric elements 5.6 may be attached so as to extend onto the end faces of both adjacent piezoelectric elements 5.6.

In addition, the reflector 8 is not attached to the end face of the bonding surface of the light emitting element 7, and the entire surface is plated after being insulated with a transparent material, except for the part where a conical lens 9 is attached in place of the reflector 8. A similar effect can be obtained by heating at °C.

As the Karman vortex 3 is generated, the piezoelectric element 5 of the vortex flow needle side big amplifier housed inside the vortex generator 2.
6 converts the occurrence of the Karman vortex 3 into a change in voltage.

A voltage generated between the two piezoelectric elements 5.6 is applied to the light emitting element 7 whose both sides are covered with two piezoelectric elements 5.6, and thereby the light emitting element 7 emits light. become. The light generated in the light emitting element 7 is reflected by the reflecting mirror 8 onto the conical lens 9, condensed, and extracted from the conical lens 9 via the optical fiber 10 as a changed light.

In particular, the eddy flow needle-side big amplifier according to the present invention, unlike conventional strain gauge strain meters, has fewer electrically charged parts, making it easy to insulate, and it extracts changes in flow rate as changes in light, making it electromagnetic. The flow rate can be detected accurately without being subjected to external disturbances.

Since the present invention is configured as an assembly, when using the vortex pickup according to the present invention, it is possible to completely and easily insulate the detection element of the vortex pickup housed inside the vortex generator. At the same time, it is possible to provide the simplest vortex flow pickup.

Note that the present invention is not limited to the assembled embodiments. That is, for example, in this embodiment, the light generated in the light emitting element is reflected by a reflecting mirror and then extracted by a conical lens, but other known methods may be used as long as they achieve the same effect. Reflectors and concentrators can also be used, and the overall shape and size of the vortex pickup can be freely changed depending on the shape and size of the vortex generator. encompasses all of them.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of a vortex generator in which a vortex needle positioning pickup according to the present invention is housed;
Fig. 3 is a perspective view of the vortex generator in which the vortex pickup according to the present invention is housed; Fig. 4 is a perspective view of the vortex pickup according to the present invention; FIG. 3 is a perspective view showing another embodiment of the invention. 1----1・・・・−1−−−−−・・−・−Vibrator 2−−−−−−−−−−・−・−・−・−1−−・
Vortex generator 3------・-11---------------
−−Karman vortex 4・−−1−−−−−−−−−1・−−
---m-Insulator 5.6-------1---1 Piezoelectric element 7...-----1--------1=-
・−Light emitting element 8−−−−1−−−−・−1−−−
−−−・−Reflector 9−・−・−11−−−−−−−・−
・−・Conical lens 10−・−・・−−1−−−−−
−−−−−−−Optical fiber patent applicant
Oval Equipment Industry Co., Ltd. Agent (7524) Shota Mogami Figure 1 Figure 2 Figure 3;:I': 4 1:/l

Claims (1)

[Claims] 1) In order to detect the vibration of a vortex generator installed in a pipe conduit forming a flow path, two piezoelectric elements are used in a vortex generator housed inside the vortex generator. In between, a light emitting element that emits light due to the voltage generated between both piezoelectric elements when the vortex generating body vibrates is bonded, a condenser is attached to one end surface of the light emitting element, and a light emitting element is attached to a surface other than the bonded surface of the light emitting element. The above pickup for vortex flow company, characterized in that a reflecting mirror is attached to the end face of the pickup except for the part where the condenser is attached. 2) A pickup for a vortex flow company according to claim 1, wherein the condenser is a conical lens.