JPS59187221A - Feedback-type fluidic flow-meter - Google Patents

Abstract

PURPOSE:To obtain the measurement performance which is sufficiently applicable to a consumer gas-meter by a method wherein a pair of flow-path forming members are composed of convex surfaces which have gentle variation of the radius of curvature and the feedback flow-paths are formed into curved shape of nearly the same shape and the same dimensions. CONSTITUTION:Control nozzles 6a, 6b and the downstream side of the conduit expanding portion 5 are connected to a pair of flow-path forming members 8a, 8b to form a pair of feedback flow-paths 7a, 7b. The flow-path forming members 8a, 8b are composed of convex surfaces which have gentle variation of the radius of curvature. The feedback flow-paths 7a, 7b are formed into curved shape of nearly the same shape and the same dimensions over the whole length and are connected to the control nozzles 6a, 6b smoothly. With this constitution, the pressure loss is reduced significantly and the conditions, such as the maximum flow should be 3m<3>/h and the minimum flow should be 30l/h or less and the pressure loss should be 15mm.H2O or less, which are required to a consumer gas-meter, can be sufficiently satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a conduit constriction section, a jet nozzle, and a conduit enlarged section are formed in sequence in the flow direction, and a pair of conduit tubes are provided at the boundary between the jet nozzle and the conduit enlarged section. A pair of control nozzles formed in a direction substantially perpendicular to the ejection direction of the ejection nozzle and facing each other, and connecting each of the control nozzles with the downstream side of the expanded pipe section. The present invention relates to a feedback type full-ink flow meter having a return flow path formed therein.

The return-type Fruit Ink flowmeter has a structure as shown in Figure 2, and uses the Coanda effect. ), the control nozzles (6a) and (6b
) by blowing out fluid alternately from the jetting nozzle (3).
The jet from
9b), the flow rate is measured based on the change in the fluid frequency caused by the change in the flow direction of the jet from the jet nozzle (3), and the mechanically movable part is It has the advantage of being less susceptible to the effects of fluid composition, temperature, and pressure.

However, as a result of various experiments, it has been found that the conventional feedback type full-build flow meter cannot be used as is for home use. In other words, for example, in the case of a household city gas meter, the maximum flow rate is JgoA] and the minimum measured flow rate is 3θt/
The minimum measured flow rate must be less than 7h, but with the conventional type, it was not possible to reduce the minimum measured flow rate to about 7h or less.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to improve a feedback fluid ink flow meter so as to obtain measurement performance that can be practically used as a household meter.

Characteristic tank 12 of the feedback type full-buoy flowmeter according to the present invention
t is a conduit enlarged part located downstream of the ejection nozzle, a pair of control nozzles formed at the boundary between the ejection nozzle and the conduit enlarged part so as to face each other at substantially right angles to the direction of ejection from the nozzle; and downstream of both brake nozzles and the conduit expansion section, 11. d) to form a return flow path connecting lJ.
Each of the pair of flow path forming parts is shaped into a convex curved surface with a gentle radius of curvature except for the part corresponding to the outlet of the control nozzle, and each of the return flow paths is formed in substantially the same shape over its entire length. The function and effect are as follows.

As a result of various experiments, we found that the cross-sectional area of the flow path between the constricted pipe section, the jet nozzle, and the expanded pipe section is large, which may be the reason why it is impossible to measure minute flow rates with the conventional method.
It was found that due to the sharp bend in the return flow path connected to the control nozzle, the loss of pressure was so large that the control nozzle could no longer impart sufficient energy to the jet. Therefore, we experimented with various measures to reduce pressure loss, and found that we improved the shape of the channel forming member, made the expanded section of the channel into a trumpet shape, and connected it smoothly to the return channel. By improving the shape of the member that forms the return flow path and the control nozzle with the forming member, the return flow path is
It has a smoothly curved shape with almost no change in cross-sectional area.
If it is connected smoothly to the control nozzle, for example, when targeting city gas, the maximum flow rate is J nJh, the minimum measured flow rate is 30z/h or less, and the pressure loss is /j tx
It has been found that it is possible to reduce x H20 or less, that is, to satisfy the conditions required for current household city gas meters, and that it can also be applied to various household meters such as water meters. As a result, compared to conventional household flowmeters, we are able to provide a household flowmeter that is less expensive, more durable, has less accuracy loss due to temperature and pressure, and is more versatile.

Next, an example will be shown with reference to FIG.

In a metal or plastic pipe (1) with a rectangular cross-sectional shape and a wide part (1c) between the small parts (1a) and I (lb), there is a conduit constriction part (2) and a jet nozzle. A pair of first flow path forming members (4a) and (4b) forming (3) are located in the small and medium portion (1a) on the upstream side, and are symmetrical with respect to the pipe center axis (P). When the fluid is smoothly guided from the jet nozzle (3) to the pipe center axis (
The structure is such that the fluid is ejected almost parallel to P).

Pipe expansion part (5), a pair of control nozzles (6a) and (6b)
), and the downstream side of the conduit expansion part (5) and the control nozzle (6
A pair of return channels (7a) that communicate with each other separately.
) + (7b) a pair of second flow path forming parts (8a
) + (8b) is arranged and fixed symmetrically with respect to the pipe center axis (P) in the large and middle part (lc) of the pipe +1), and a pair of control nozzles (6a c (6b) are At the boundary between the jet nozzle (3) and the expanded pipe section (5), the jet nozzle (3) is oriented substantially perpendicularly to the jet direction of the jet nozzle (3) and opposed to it, so that the fluid from the jet nozzle (3) is is configured so as to inject the small and medium portion (lb) on the downstream side along either one of the inclined surfaces (9a) + (9b) of the conduit expansion part (5), and both control nozzles (6a) - By reversing the magnitude relationship of the fluid energy given to the fluid from the jet nozzle (3) by (6b) and the amount of fluid energy given by both control nozzles (6a) + (6b) K, the jet nozzle The fluid from (3) is transferred to the inclined surface (9a)T(91))K
This is explained in more detail below.

In other words, when fluid ejection from the ejection nozzle (3) starts, the ejected fluid flows along one inclined surface (9a) K due to the aforementioned Coanda effect, and therefore, the ejected fluid flows along one inclined surface (9a) K.
A return flow path (7) is connected to the control nozzle (6a) located on the side (9a).
Large fluid energy is applied from a) so that the ejected fluid flows along the opposite inclined surface (9b),
This time, the fluid energy from the control nozzle (6b) on the opposite side causes the ejected fluid to flow again along the slope (9a) along which it started.

In this way, the fluid from the ejected fluid comes to alternately follow the slopes (9a) and 9b), and moreover, as the amount of ejected fluid increases, the period becomes shorter.
Moreover, the flow direction of the ejected fluid changes in a state where there is a quantitative correlation.

A return flow path (7a) connected to one control nozzle (6a)
In addition, there is a sensor (l) that detects pressure changes or flow rate changes.
O), and a flow rate display device (11) that calculates and displays the flow rate in the pipe (1) from the frequency of the pressure or flow rate change based on the information from the sensor (In), It consists of a feedback oscillation type full-build flowmeter.

Each of the first flow path forming materials (8a) and (8b5) is formed into a shape in which a portion other than the portion (13) corresponding to the outlet of the control nozzle (6a) + (6b) has a convex curved surface with a gentle change in radius of curvature, The flow path enlarged portion (5) and the return flow path (7a) + (7b) are smoothly connected, and the pipe (1) and the first flow path forming member (4a) +
(4b) is formed to face the second flow path forming parts (8a) + (8b) at approximately equal distances, so that each of the return flow paths (7a) + (7b) has a total length. The control nozzles (6a) and (6b) are formed into a smoothly continuous curved shape, and have approximately the same shape and size throughout, and the first flow path forming member (4)
a) + (4b) is formed so that the inside of the flow path changes gradually from the upstream small and medium portion (1a) to the jet nozzle (3), and furthermore, the exposed inner surface of the pipe (1) and the first and first flow path forming member (4a) + (4b) + (8a) ν(
8b) All exposed surfaces inside the pipe are coated with Teflon (I2), and as a whole, the pressure loss of the flowmeter is small, the accuracy is less than ijmH20, and the maximum flow rate is 3.
-/h, the configuration t7 is such that the minimum measured flow rate is 3θt/h or less.

Next, another example will be shown.

Instead of coating with Teflon θ2), the tube fl and flow path forming member (4a) ν(4b)+(8a)a(8b)
Even if T7 is made of fluorinated graphite, the same effect of reducing pressure loss can be obtained. However, the material forming the flow path may be any material such as metal or plastic.

As mentioned above, in the flow path section extending from the upstream small and medium portion (1a) to the jet nozzle (3), is it desirable to smoothly change the inside of the flow path, or is it possible to change the shape of the flow path section? It is possible.

The mechanism for detecting and detecting fluid vibrations, such as the detection method, configuration, installation position and number of the sensors (IO), can be freely changed, and the device for detecting and displaying the flow rate can also be modified in various ways.

The flow meter according to the present invention is mainly used for household use in fuel gas, water supply, etc., but it is not limited to that use.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a main part showing an embodiment of the present invention. FIG. 2 is a schematic sectional view of the main parts of a conventional example. (2)...Pipe constriction part, (3)...Blowout nozzle, (5)...Pipe enlargement part, (6a)
(6b) -- system #11 nozzle, (7a) + (7b)・
... Return flow path, (8a) + (8b) ... Channel forming member, (13) ... Portion corresponding to the nozzle exit.

Claims (1)

[Claims] Pipe constriction section (2), jet nozzle (3) and conduit enlargement section (
5) are formed in series in the flow direction, and a pair of restricting nozzles (6a) + (6b) are formed at the boundary between the jet nozzle (3) and the expanded pipe section (5). The spout nozzle (3
) in a direction substantially perpendicular to the direction of ejection, and
The control nozzles (6a) and (6b) are formed opposite to each other.
) A return fluid ink flowmeter forming a pair of return channels (7a) + (7b) connecting the downstream side of the conduit enlarged part (5) with the conduit enlarged part (6), Return flow path (7a) □ (7b) and control nozzle (6a)) (6
A pair of flow path forming members (8a) and (8b) forming b)
Each of the return channels (7a) and (7b) is formed into a convex curved surface with a gentle radius of curvature except for the portion θ3) corresponding to the outlet of the control nozzles (6a) 1 (6b). A feedback type full-ink flowmeter that has a curved shape that is approximately the same shape and size over its entire length.