JPH0577723U - Fluid vibration type flow meter - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the outlet position is offset, it does not adversely affect the flow rate measurement error. [Structure] The fluidic oscillation element 1 is composed of a nozzle 2, an inner wall surface 4A of an enlarged flow path downstream thereof, and a target 3 downstream of the nozzle 2. Downstream of the enlarged flow path 4, a narrow flow path 6 is arranged symmetrically with respect to the axis Y-Y of the nozzle 2. Another enlarged flow passage 7 is formed downstream of the flow passage 6, and the outlet 5 communicates with this.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a fluid vibration type flow meter.

[0002]

[Prior Art]

 As a fluid vibration type flow meter, one using the fluidic oscillation element 1 shown in FIG. 3 is well known. Reference numeral 2 is a nozzle, 3 is a target disposed downstream of the nozzle 2, and 4 is an enlarged flow path portion provided immediately downstream of the nozzle 2 and constitutes a vibration generating chamber. The target 3 is arranged in this vibration generating chamber.

Reference numeral 5 is a narrowed outlet provided downstream of the enlarged flow path portion (vibration generating chamber) 4. In such a conventional fluid vibration type flow meter, the target 3 and the enlarged flow path portion 4 are formed symmetrically with respect to the upper and lower axes passing through the center of the left and right widths of the nozzle 2, and the outlet 5 is also the same. It was arranged in a symmetrical position with respect to the upper and lower axes passing through the nozzle.

Therefore, the outlet 5 was provided at the center of the left and right width W of the fluidic oscillator 1.

[0005]

[Problems to be solved by the device]

 In order to put this type of fluid vibration type flow meter into practical use as a small-sized gas meter, the outlet 5 should not be located in the center of the width W of the meter, but rather should be installed at a position offset to the right or left from the center, and piping for installing the meter There is a strong demand for the realization of freedom.

However, if the outlet 5 is provided to the right or left from the center of the width W, the stability of the unit pulse with respect to the flow rate is lost, and, for example, as shown in FIG. There was a problem that vibration, that is, the unit pulse fluctuated, and the measurement error of the flow rate became large.

Therefore, an object of the present invention is to provide a fluid vibration type flow meter capable of solving such a problem.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a fluid vibration type flow meter of the present invention comprises a slit-shaped nozzle and an enlarged flow passage which is provided on the downstream ejection side of the nozzle and is formed on the axis of the nozzle in the flow direction. In a flowmeter having an inner wall surface and a target arranged in the enlarged flow passage on the nozzle axis, a narrow flow passage provided downstream of the enlarged flow passage and symmetrical to the nozzle axis, and the narrow flow passage. It was provided with another expansion channel provided downstream of the channel and an outlet communicating with the downstream of the other expansion channel.

It is convenient for a gas meter to use a fluidic oscillation element as an element that generates fluid vibration.

[0010]

[Action]

 Due to the buffering action of the narrow flow passage provided on the downstream side of the enlarged flow passage and formed symmetrically with the axis of the nozzle, and another enlarged flow passage provided downstream of this narrow flow passage, the outlet position is set to the nozzle. Even if it deviates from the axis line of, the flow rate measurement error is not adversely affected.

[0011]

【Example】

 In FIG. 1, reference numeral 1 denotes a fluidic oscillation element as a fluid vibration generating element, which is a slit-shaped nozzle 2 extending in a direction perpendicular to the plane of the paper, and a nozzle 2 provided downstream of the nozzle 2 in the flow direction of the nozzle 2. The expansion channel 4 formed symmetrically with respect to the axis Y-Y, the expansion channel inner wall surface 4A surrounding the expansion channel 4, and the expansion channel 4 arranged on the axis Y-Y of the nozzle 2 in the expansion channel 4. It consists of target 3.

Reference numeral 6 denotes a narrow flow passage which is provided on the downstream side of the enlarged flow passage 4 and which is formed symmetrically with the axis 2 of the nozzle 2. The narrow flow passage 6 communicates with the narrow flow passage 6, and another enlarged flow passage 7 is provided downstream. And an outlet 5 is arranged in communication with the downstream side of the further enlarged passage 7.

As is well known, a differential pressure sensor that detects a differential pressure of fluid vibrations on both sides of the target 3 and converts the differential pressure into an electric signal, and an arithmetic circuit that calculates an integrated flow rate from an electric signal of the differential pressure sensor. And a liquid crystal display for displaying the accumulated gas usage amount is provided and constitutes a gas meter, but these well-known parts are not shown.

As shown in FIG. 1, the outlet 5 is not symmetrically arranged with respect to the axis Y-Y of the nozzle 2 and is offset, but in this embodiment, when the unit pulse was measured by changing the flow rate. Around the time, as shown in FIG. 2, the unit pulse is very stable as compared with the conventional technique.

In the above embodiment, it is described that the enlarged flow passages 4, 7, the enlarged flow passage inner wall 4A, and the narrow flow passage 6 are provided symmetrically with respect to the axis Y-Y of the nozzle 2. This expression is the expression in the cross-sectional view of FIG. 1. Strictly speaking, it is formed symmetrically with respect to a plane including the axis Y-Y of FIG. 1 and perpendicular to the plane of the drawing.

[0016]

[Effect of the device]

 Since the fluid vibration type flow meter of the present invention is configured as described above, even if the outlet positions are offset, there is little adverse effect on the flow rate measurement error, so there is less freedom in mounting the flow meter. This also increases the degree of freedom in terms of external design.

Further, by using the fluidic oscillation element, it is effective as a gas meter which is particularly required to be accurate and downsized.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an essential part of an embodiment of the present invention.

FIG. 2 is a diagram of a unit pulse according to an embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view of a conventional technique.

FIG. 4 is a diagram of a unit pulse of a flow meter.

[Explanation of symbols]

 1 Fluidic Oscillator 2 Nozzle 3 Target 4 Expansion Channel 4A Expansion Channel Inner Wall 5 Exit 6 Narrow Channel 7 Another Expansion Channel

Claims (2)

[Scope of utility model registration request] 1. A slit-shaped nozzle, an inner wall surface of an enlarged flow passage, which is provided on a downstream ejection side of the nozzle and is formed symmetrically with respect to an axis of a flow direction of the nozzle, and arranged in the enlarged flow passage on the nozzle axis. In a flowmeter having a target, a narrow channel provided on the downstream side of the expanded channel and symmetrically formed with respect to the axis of the nozzle, and another expanded channel provided downstream of the narrow channel, A fluid vibration type flow meter comprising an outlet communicating with the downstream side of another enlarged flow path. 2. The fluid vibration flowmeter according to claim 1, wherein the element that generates fluid vibration is a fluidic oscillation element, and the flowmeter is a gas meter.