JPH04262209A - Fluidic flowmeter having micro-flow sensor - Google Patents

Abstract

PURPOSE:To improve an instrument error characteristic by obtaining an excellent vibration waveform in fluidic element wherein a partition plate is inserted into a nozzle. CONSTITUTION:A partition plate is made to protrude into the upstream side of a throat part 2a of a nozzle 2 and made to expand. Thus, fluid which flows into the nozzle is divided in layer states. The fluid before entering in the nozzle 2 is also divided into layer states. Therefore, the straightening effect in the nozzle is further enhanced, and the excellent vibration waveform is formed. When this flowmeter is applied in a gas meter, the instrument error characteristic can be reduced within one percent.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is configured such that flow rate measurement in a small flow rate range is carried out by a micro flow sensor incorporated in a nozzle portion of a fluidic element, and that the nozzle portion in which this micro flow sensor is incorporated is The present invention relates to a so-called fluidic flowmeter with a microflow sensor that has a structure in which a plurality of partition plates are inserted to divide the flow in the vertical direction.

0002

[Prior Art] Since there is a limit to flow rate measurement in a small flow rate range using a fluidic element, for flow rates below this limit, a micro flow sensor is built into the nozzle. It is driven to measure the flow rate in a small flow area. Such a method is also used in large gas meters, for example, but in the case of large fluidic elements, the cross-sectional area of the nozzle portion is naturally large. For this reason, when the flow rate passing through the nozzle becomes small, the flow distribution becomes non-uniform and the measurement sensitivity of the microflow sensor decreases.

Therefore, conventionally, as shown in FIG.
By inserting multiple stages to divide the flow, sensitivity in small flow areas is improved.

0004

[Problems to be Solved by the Invention] However, when the partition plate 6 is inserted in this way, the fluid flowing through the wide flow path is constricted by the throat portion 2a of the nozzle 2. The problem is that turbulent flow occurs in the chamber, and this turbulent flow flows directly into the flow path partitioned by the partition plate, which in turn flows directly into the fluid vibration generation chamber, deteriorating the instrumental error performance or fluidic oscillation waveform. There is.

An object of the present invention is to improve the structure of the partition plate in a fluidic flowmeter with a microflow sensor in which the partition plate is inserted into the nozzle portion so as not to deteriorate the instrumental error performance and the oscillation waveform.

[0006]

[Means for Solving the Problems] The structure of the present invention proposed to achieve the above object is as follows.

[0007] Flow rate measurement in a small flow rate range is carried out by a micro flow sensor built into a nozzle section of a fluidic element, and a plurality of nozzle sections in which the micro flow sensor is built in divides the flow vertically. A fluidic flowmeter with a micro flow sensor configured to have a partition plate inserted therein, in which a tip of the partition plate protrudes and enlarges toward the upstream side of a throat portion of a nozzle.

[0008]

[Operation] The fluid flowing into the nozzle is first divided into layers by the partition plate at the throat portion and then squeezed into the nozzle, and then passes between the partition plates partitioned into multiple stages. Then, it is ejected into the fluid vibration generation chamber, where it generates fluid vibrations. The generated fluid vibration is detected by the fluid vibration detection end, converted into an electrical signal, and input to the flow rate calculation device, where the integrated flow rate is calculated.

[0009]

[Embodiment] Fig. 1 shows a fluidic flowmeter with a micro flow sensor in which the present invention is implemented.

Reference numeral 1 indicates a fluidic element, 2 indicates a nozzle, 2a indicates a throat portion of the nozzle 2, 3 indicates a fluid vibration generation chamber, 4 and 4a indicate a fluid vibration detection unit, and 5 indicates a microflow inserted into the nozzle 2. The sensor 6 is a partition plate that partitions the inside of the nozzle 2 into multiple stages in the vertical direction, and the front end 6a side of the partition plate 6 is connected to the flow path from the throat part 2a of the nozzle 2 to the inlet side, as shown in FIGS. 1 and 2. 7 and is enlarged from side to side.

In the case of the embodiment, the throat portion 2a of the nozzle 2 is formed to have a large divergence angle so that the inflow can be carried out smoothly.

In the case of the fluidic flowmeter described above, the fluid is separated vertically at the tip 6a of the partition plate 6 before flowing into the nozzle 2, and flows into the nozzle 2 in a rectified state from the throat portion 2a. Therefore, there is no turbulence in the fluid ejected from the nozzle 2 into the fluid vibration generating chamber 3, and therefore accurate fluid vibrations are generated.

FIG. 3 shows a fluid vibration waveform according to the present invention, and FIG. 4 shows a fluid vibration waveform of a conventional fluidic flowmeter. By comparing the two, it can be seen that in the case of the present invention, the waveform is extremely rectified. It can be seen that a waveform is obtained.

FIG. 5 shows the instrumental error characteristic when the present invention is applied to a gas meter. In the case of the present invention, the width of the instrumental error characteristic can be kept within the range of ±1%.

[0015]

Effects of the Invention As described above, in the present invention, the tip side of the partition plate inserted into the nozzle is made to protrude and expand upstream of the throat portion of the nozzle, so that the fluid is divided into layers before flowing into the nozzle. rectified. As a result, the fluid vibration waveform generated on the fluidic element side is adjusted while increasing the sensitivity of the microflow sensor, and when applied to a gas meter, for example, the instrumental error characteristic can be kept within a range of 1%.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a fluidic device implementing the present invention.

FIG. 2 is a perspective view of a partition plate.

FIG. 3 is an explanatory diagram of waveforms according to the present invention.

FIG. 4 is an explanatory diagram of waveforms in a conventional example.

FIG. 5 is a comparative explanatory diagram of instrumental error characteristics when the present invention and a conventional example are applied to a gas meter.

FIG. 6 is an explanatory diagram of a fluidic element into which a conventional partition plate is inserted.

[Explanation of symbols]

1 Fluidic element 2 Nozzle 2a Throat part 3 Fluid vibration generation chamber 4, 4a Detection part 5 Micro flow sensor 6 Partition plate 6a Tip 7 Inlet side flow path

Claims (1)

[Claims] Claim 1: Flow rate measurement in a small flow rate range is performed by a micro flow sensor built into a nozzle part of a fluidic element, and the flow is vertically divided into the nozzle parts in which this micro flow sensor is built in. A fluidic flowmeter with a micro flow sensor is constructed in which a plurality of partition plates are inserted, in which a tip of the partition plate is enlarged to protrude upstream of a throat portion of a nozzle.