JPS6117380Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for calibrating a flow meter.

FIG. 1 shows a schematic structure of a flowmeter calibration device, in which water in a water tank 1 is supplied to an upper water tank 6 through a pipe 2, a valve 3, a pump 4, and a riser pipe 5.

In addition, an overflow part 7 for keeping the water level in the upper water tank 6 constant and a descending pipe 10 for returning the overflow water from the overflow part 7 to the water storage tank 1 are provided, and in addition, the upper water tank 6 is provided with an air vortex to prevent the generation of air vortices. A perforated plate (or grid) 8 for rectification is provided which also serves as a rectifier.

Water falling from a nozzle 22 via a test flowmeter 12 and a flow rate adjustment valve 13 through a downcomer pipe 11 connected to a bell mouth 9 in the upper water tank 6 was arranged to be able to swing downward. The flow is selectively diverted to either one of the weighing channel 15 and the discharge channel 16 by the commutation plate 14 .

The discharge channel 16 is connected to the water storage tank 1, and the weighing channel 15 is connected to the weighing tank 17, so that the amount of water stored in the weighing tank 17 within a predetermined time is weighed by the weighing device 20. It's getting old.

After the water in the weighing tank 17 is weighed, the valve 18 is opened and the water in the weighing tank 17 is discharged to the water storage tank 1 through the discharge pipe 19.

The swing mechanism of the baffle plate 14 is constructed as shown in FIG. 2, and the rotary shaft 24 of the baffle plate 14 is rotated by a fluid pressure cylinder 27 via an arm 28.

In addition, the reference numeral 21 in FIG. 2 indicates a collecting cylinder, 23 indicates a side plate that prevents flowing water from spreading and dissipating in the width direction of the diversion plate 14, and 25 indicates a nozzle 2.
Space within the enclosure to receive water falling from 2, 26
indicates an inclined member that partitions the weighing flow path 15 and the discharge flow path 16.

The outlet of the nozzle 22 has a rectangular shape with a long width W ₁ and a short side B, and the width W ₂ of the commutator plate 14 is larger than the width W ₁ of the outlet of the nozzle 22 .

As shown in FIG. 3, the commutation plate 14 has a 2θ≦60
The rotation is switched within a range of 20°, and the angle C in the figure is the run-up section angle, since the commutator plate 14 runs at a constant angular speed until it reaches the beginning of the short side B of the nozzle 22 and passes through it. It is set in.

In this way, when the commutation plate 14 crosses the water flow falling from the nozzle 22 at a constant angular velocity, the transition time at the time of switching (0.1 to 0.3 sec) Δt ₁ , Δt ₂ , the areas D and E in the figure are equal, and the areas F and G are equal with respect to the respective midpoints, so the weighing tank 17 (first
The amount of water V (m ³ ) measured in Figure 4) corresponds to the amount of water in the rectangular area at time Σt (sec) in Figure 4, and therefore the average flow rate Q (m ³ /sec) is as follows: Become.

Q=ΣV/Σt This flow rate Q is compared with the indicated value of the flowmeter 12 (see FIG. 1), and the flowmeter 12 is calibrated based on this.

By the way, in the conventional flow meter calibration device, as shown in FIG. 3, the commutation plate 14 protrudes upward by a length L with respect to the vertical boundary surface of the water flow falling from the nozzle 22 in the commutation state. However, in reality, the water flow that hits the diversion plate 14 may swell upwards, causing an overflow that exceeds the upper edge of the diversion plate 14. When such an overflow occurs, the flow rate increases. There is a problem that errors occur in the measured values.

The present invention is an attempt to solve these problems, and aims to provide a flowmeter calibration device that sufficiently prevents the occurrence of overflow at the commutation plate and improves measurement accuracy. purpose.

For this reason, the flow meter calibration device of the present invention has a nozzle with a rectangular outlet for dropping liquid, and a nozzle that selectively sends the liquid falling from the nozzle to either a weighing channel or a discharge channel. a flow diverter plate swingably disposed below the outlet of the nozzle in order to divert the flow to In order to prevent the liquid from overflowing, an auxiliary diversion plate is provided along the surface of the diversion plate at a position spaced apart from the surface to divide the liquid into layers and allow it to flow down.

Embodiments of the present invention will be described below with reference to the drawings. Figures 5 and 6 show a flow meter calibration device as the first embodiment of the present invention, and Figure 5 is a front view showing the main parts thereof. FIG. 6 is a sectional view taken along the - line in FIG. 5.

The flowmeter calibration device of the present invention has a schematic structure similar to that shown in FIG. A swingable diversion plate 14 is provided to selectively divert the flow to either one of the utility flow path 15 and the discharge flow path 16.

Also, symbols 21, 23, 26, B in Figures 4 and 5
2 indicates the same components as those indicated by the same reference numerals in FIG.

However, in the device of the present invention, as shown in FIGS. 5 and 6, the flow diverted by the diverter plate 14 is
In order to prevent the liquid from overflowing beyond the upper edge of the commutation plate 14 to the opposite side, an auxiliary commutation plate 29 is provided along the surface of the commutation plate 14 at a distance from the surface to divide the liquid into layers and allow it to flow down. , are attached to the side plate 23 via the ribs 30 and the reinforcing plate 31, and are provided integrally with the commutation plate 14.

The upper end of the auxiliary commutation plate 29 is made thin so that the liquid that hits it can be easily cut off and the liquid can be prevented from rebounding. The upper end of the auxiliary commutation plate 29 is curved along the downward direction of the liquid, so that the angle of incidence of the liquid on the auxiliary commutation plate 29 is almost zero, and the thickness of the flowing liquid is reduced. Approximately 30-60
% of the auxiliary commutation plate 14.

The width of the commutation plate 14 is at least 1.3 times the width W ₁ of the nozzle 22, and regarding the arrangement of the auxiliary commutation plate 29, the intervals a and b in FIG. 6 are each 0.6 of the short side dimension B of the nozzle 22. It is said to be more than double. Further, the length of the auxiliary diverter plate 29 in the direction of the flow of the liquid is made shorter than the length of the diverter plate 14, thereby preventing blockage of the water channel due to splashing or the like.

As mentioned above, when the auxiliary diverter plate is provided and the function of dividing the flowing fluid into layers is performed, the load on the diverter plate 14 is reduced, and a small flow rate is essentially given. Therefore, the reverse rise of the liquid is suppressed, and the occurrence of overflow over the upper edge of the commutation plate 14 is prevented.

Therefore, the above-mentioned flow rate Q can be measured accurately, and the flow meter can be calibrated appropriately.

Note that by extending the width of the commutation plate 14 so as to be laterally longer than the width W ₁ of the outlet of the nozzle 22 by ΔW, it is possible to contribute to preventing the above-mentioned overflow. This overhang amount △W is
It is desirable to set it to 15% or more of W ₁ .

7 and 8 show a flowmeter calibration device as a second embodiment of the present invention, and FIG. 7 is a front view thereof;
FIG. 8 is a sectional view taken along the - line in FIG. 7.

In this second embodiment, the auxiliary commutation plate 29 is
Although it is directly attached to the commutation plate 14 via 0,
In other respects, it is configured similarly to the first embodiment described above,
As a result, substantially the same effects as in the first embodiment can be obtained.

As described in detail above, the flowmeter calibration device of the present invention is simple in that an auxiliary commutation plate is provided along the surface of the commutation plate and at a distance from the surface to divide the liquid into layers and allow it to flow down. This structure has the advantage of reliably preventing overflow of fluid hitting the commutation plate and improving measurement accuracy.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the schematic structure of a flowmeter calibration device, Fig. 2 is a perspective view showing the main parts of a conventional flowmeter calibration device, and Fig. 3 is an action of the commutator plate in the conventional device. FIG. 4 is a graph for explaining the point of flow measurement in a flow meter calibration device, and FIGS. 5 and 6 show a flow meter calibration device as a first embodiment of the present invention. 5th thing
The figure is a front view showing the main parts, FIG. 6 is a sectional view taken along the - line in FIG. 5, and FIGS. 7 and 8 show a flow meter calibration device as a second embodiment of the present invention. , Fig. 7 is its front view, and Fig. 8 is the − of Fig. 7.
It is a sectional view along a line. 1...Water tank, 2...Piping, 3...Valve, 4
... Pump, 5 ... Rise pipe, 6 ... Upper water tank, 7 ... Overflow part, 8 ... Perforated plate for rectification, 9 ... Bell mouth, 10 ... Downpipe, 11 ...
... Downpipe, 12 ... Test flow meter, 13 ... Flow rate adjustment valve, 14 ... Diverter plate, 15 ... Weighing channel, 1
6... Discharge channel, 17... Weighing tank, 18...
... Valve, 19 ... Discharge pipe, 20 ... Weighing device,
21... Collection cylinder, 22... Nozzle, 23... Side plate, 24... Rotating shaft, 25... Space within the surrounding wall,
26... Inclined member, 27... Fluid pressure cylinder, 2
8... Arm, 29... Auxiliary commutation plate, 30... Rib, 31... Reinforcement plate.

Claims (1)

[Scope of utility model registration request] A nozzle having a rectangular outlet for dropping a liquid, and a lower part of the outlet of the nozzle for selectively diverting the liquid falling from the nozzle to either a weighing channel or a discharge channel. The diversion plate is provided with a diversion plate that is swingably disposed on the diversion plate, and in order to prevent the flow diverted by the diversion plate from overflowing to the opposite side beyond the upper edge of the diversion plate. A flow meter calibration device, characterized in that an auxiliary diversion plate is provided along the surface of the diversion plate at a position spaced apart from the surface to divide the liquid into layers and allow it to flow down.