JPH04262210A - Fluidic flowmeter having micro-flow sensor - Google Patents

Abstract

PURPOSE:To improve the sensitivity of a flow sensor which is inserted into a nozzle flow path. CONSTITUTION:A flow sensor flow path 7 is formed by partitioning the inside of a nozzle flow path 3. The inlet angle of the flow sensor flow path 7 is set at the value larger than the other part so that the flow speed gradient becomes large. Since the improvement is achieved so that the flow speed gradient becomes large at a part wherein a flow sensor 4 is inserted, the sensitivity of the flow sensor 4 is improved especially in a minute flow rate region.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidic flowmeter with a microflow sensor that measures in a small flow rate range using a microflow sensor built into a nozzle channel.

0002

[Prior Art] A micro flow sensor (hereinafter referred to as a "flow sensor") is a system that detects the flow rate by electrically capturing the flow velocity, so it is ideal to insert its sensing part in the center of the nozzle flow path. It is.

However, if the sensitive part is inserted into the center of the nozzle flow path, the thin lead becomes long and may be displaced by the flow velocity or impact, resulting in measurement errors. Furthermore, if the leads are made thicker in order to prevent these problems, there is a fear that the flow within the nozzle flow path will be disturbed and the oscillation of the fluidic element will be adversely affected. For this reason, the flow sensor is inserted into the nozzle channel near the bottom wall or top wall.

0004

For this reason, the flow velocity of the fluid decreases near the wall, and there is a problem in that the sensitivity decreases due to the influence of the wall.

[0005] An object of the present invention is to improve the sensitivity of a flow sensor incorporated in a nozzle portion in a fluidic flowmeter.

[0006]

[Means for Solving the Problems] The structure of the present invention is as follows.

[0007] In a fluidic flowmeter incorporating a flow sensor in the nozzle portion, a part of the nozzle flow path in which the flow sensor is located is separated from other parts to form a flow sensor flow path, and the flow sensor flow path is separated from other parts. A fluidic flowmeter with a micro flow sensor that has a larger inlet angle than other nozzle flow path inlets.

[0008]

[Operation] The fluid to be measured passes through the nozzle flow path and is ejected into the fluidic vibration oscillation chamber, where fluid vibrations are generated. This fluid vibration is electrically captured and input to the calculation circuit, and the flow rate is Calculated.

On the other hand, in the small flow rate range, the flow sensor
For example, the flow velocity of the fluid to be measured flowing in the nozzle flow path is detected intermittently, and this signal is input to the arithmetic circuit.
The flow rate is calculated.

[0010] During such measurements, the inlet of the flow sensor flow path is opened more widely than other parts, so the pressure loss at the inflow part is small, but the pressure loss of the entire nozzle part is As a result, the pressure loss in the flow path portion where the flow sensor is attached increases, and the flow velocity of the fluid to be measured becomes higher than that in the flow path where the inflow portion is not enlarged.

[0011] As a result, the flow velocity gradient in the flow sensor portion becomes large, and the flow sensor performs highly sensitive detection even in a minute flow rate range, compared to a case where no flow sensor flow path is formed.

0012

[Example] FIG. 1 shows the inside of the nozzle flow path 3 of the nozzle 2,
It is a fluidic element with a flow sensor 4 inserted into the top wall side, and 5 and 5' are vibration detection ports.

In FIGS. 1 and 2, 6 is a separator inserted into the top wall side where the flow sensor 4 is inserted, and the rear end 6' of this separator 6 is located in front of the spout 3a of the nozzle flow path 3. It's stopped.

Reference numeral 7 denotes a flow sensor flow path formed by a separator 6, and an inlet wall 7 of this flow sensor flow path 7
As shown in FIG. 4, ' is wide open Q1 with respect to the width Q of the other nozzle flow path inlet wall 3', and is designed to facilitate the inflow of fluid.

In the case of the embodiment, only one separator 6 is inserted into the nozzle flow path 3, but the separator 6 is similarly inserted in multiple stages to divide the nozzle flow path in the vertical direction. The performance of the fluidic element may be improved by stabilizing the fluidic element.

In the above embodiment, a flow sensor flow path 7 is formed by the separator 6, and the flow velocity within this flow path 7 is designed to be increased, so that the flow velocity gradient increases greatly from q to q1, as shown in FIG. This improves the sensitivity of the flow sensor 4 accordingly.

[0017]

As described above, the present invention is designed to increase the flow velocity and increase the flow velocity gradient in the portion where the flow sensor is inserted, so that the measurement accuracy is improved particularly in the small flow rate range.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a fluidic device implementing the present invention.

FIG. 2 is a perspective view of a nozzle portion.

FIG. 3 is an explanatory diagram of a flow velocity gradient in a nozzle flow path.

FIG. 4 is an explanatory diagram of the nozzle flow path entrance angle.

[Explanation of symbols]

1 Fluidic element 2 Nozzle 3 Nozzle flow path 3' Nozzle flow path inlet wall 4 Flow sensor 5, 5' vibration detection port 6 Separator 6a Rear end 7 Flow sensor flow path 7' Flow sensor channel inlet wall

Claims (1)

[Claims] Claim 1: In a fluidic flowmeter incorporating a microflow sensor in a nozzle part, a part of the nozzle channel in which the microflow sensor is located is separated from other parts to form a flow sensor channel, and the flow A fluidic flowmeter with a microflow sensor that has a sensor flow path with a larger inlet angle than other nozzle flow path inlets.