JPS6326849B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a flow meter inspection device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flow meter inspection device that allows one or several dozen flow meters to be tested accurately in a short period of time.

Regarding a device for inspecting this type of flow meter, the present applicant previously filed Japanese Patent Application No. 55-37377 (Japanese Unexamined Patent Publication No. 55-37377).
33628) was developed.

In general, when a flow meter such as a gas meter that operates at a normal flow rate is used to flow a minute flow rate for a pilot fire, the rotation speed of the rotating drum decreases significantly, so it is difficult to test the flow meter at a minute flow rate. Although it required a considerable amount of time, the applicant was able to efficiently inspect the flowmeter in a very short time using the above-mentioned fast forwarding device.

The object of the present invention is to provide a flowmeter testing device that can quickly and efficiently test the accuracy of one or more flowmeters using this fast-forwarding device.

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a standard flow rate generation chamber capable of generating standard or different standard flow rates, and in the illustration, two or more sonic nozzles 2 with the same or different flow rates;
2'... are fixed approximately at the center of the chamber 1 along the partition wall 3 and separate the front chamber 4 and the rear chamber 5. Reference numeral 6 denotes a pipe body connected to the front chamber 4 of the chamber 1 with one end open, and is connected to a large number of flowmeters M ₁ ,
_{M2 , .} V ₁ , V ₃ ,
...Interpose V _o-3 and V _o-1 . Further, valves V' ₂ , V 2 , V' 4 , and valves V' 2 , V ₂ , V' ₄ , and
V ₄ , ...V′ _o-3 , V _o-3 , V′ _o , and _Vo are provided, and all these valves are connected to a control device A that can perform calculations, so that they can be freely controlled. .

Reference numeral 9 denotes a pipe body connected to the rear chamber 5 of the reference flow rate generation chamber 1, and a desired fluid generation source F, for example, a vacuum pump, is interposed therein.

Therefore, by operating this vacuum pump F and selectively using the required number of sonic nozzles 2, 2', . It is possible to maintain the so-called standard flow rate of your choice.

10, 10'... is the rear chamber 5 of the chamber 1
A valve opening/closing mechanism attached to each of the sonic nozzles 2, 2', .

11 is a flow meter for each test object M ₁ , M ₂ , ... M _o-1 ,
A flow rate counter such as a pulse signal generator or a pulse detection device that is proportional to the flow rate is provided at M _o and is connected to the control device A in the same way as the valve.

In addition, the control device A measures the time of 1 to N pulses of each flowmeter to be tested using a large flow rate, and calculates or sets a time shorter than that time for each flowmeter to be tested. , the fluid continues to flow at a large flow rate until the set time, then switches to the desired small flow rate, detects the next pulse signal, performs positioning, and then flows until the desired measured amount is reached. Calibration can be performed by comparing the flow rate with the scale display for each flowmeter to be tested.

For example, as shown in Figure 2, the flowmeter to be tested is
A pulse signal from a unit flow rate generator 13 having an appropriate configuration on the display drum _{12 is detected by the flow rate counter 11 of M 1 ,} M _{2 , .} . . 14, and by selectively using the required number of sonic nozzles ₂ , ₂ ', .
The periods T ₁ , T _{2 .} . . of the pulse signals are first measured by applying flow rates equivalent to the large flow rates of M _o-1 and M _o , and the periods T ₁ , T ₂ . At the same time, a slightly shorter time ΔT is set than the periods T ₁ , T _{2 .} . . and this is transmitted to the sonic nozzle 2,
2'... can be applied as a sonic nozzle switching signal to control the valve opening/closing mechanisms 10, 10'...

Therefore, the selection conditions of the sonic nozzles 2, 2', . Instrumental error can be tested by comparing the flow rate of the flowmeter under test and the reference flow rate determined by .

In the figure, 16, 17, and 18 indicate a thermometer, pressure gauge, and hygrometer installed in the front chamber 4, and 19 indicates a thermometer in the tube body 6, which can be connected to the control device A to correct the reference flow rate. It's becoming like that.

The operation of this invention will be explained based on the above configuration.

First, close the switching valves V ₁ , V ₃ , ...V _o-3 , V _o-1 , and close the valves V' ₂ , V ₂ , V' ₄ , V ₄ , ... V' _o-2 ,
Open V _o-2 , V′ _o , and V _o and set the flowmeter under test M ₁ ,
A large flow rate commensurate with the maximum _flow rate allowed by M _{2 ,} .

The pipe body 6 includes the flow meters M ₁ , M ₂ , . . .
Since a large number of M _o-1 and M _o are connected in series, flow rate measurement proceeds simultaneously, and each flow meter M ₁ , M ₂ ,...
The pulse signal for each M _o-1 and M _o is detected and the control device A
Each period T ₁ , T ₂ . . . is measured in .

Then, set a time shorter than these cycles T ₁ , T _{2 .} . . by ΔT, and after the set time elapses, the valves of the respective flow meters M ₁ , M ₂ , . . . M _o-1 , M _o
V′ ₂ , V ₂ , V′ ₄ , V ₄ , ...V′ _o-2 , V _o-2 , V′ _o , V _o
are closed one after the other, and in the opposite direction the switching valves V ₁ , V ₃ ,...
The control device A detects the signal that opens V _o-3 and V _o-1 and switches the valves most delayed, and transmits this as a sonic nozzle switching signal, and the sonic nozzle 2, 2'... Select the valve opening/closing mechanism 10,
10'... changes from a large flow rate to a small flow rate. Then, this small flow rate can be used as a reference flow rate to flow into the pipe body 6.

In this way, as soon as the standard small flow rate flows into the pipe body 6, the switching valves V ₁ , V ₃ , ...V _o-3 , V _o-1 are closed, and the valves V' ₂ , V ₂ , V' ₄ , V ₄ ,...V′ _o-2 ,
Open V _o-2 , V′ _o , V _o and read each flow meter M ₁ , M ₂ ,...
Restart flow measurement of M _o-1 and M _o .

Then, after detecting the next pulse signal, compare the flow rate of the test flowmeter obtained by measuring the time between the next selected pulse signals and the reference flow rate during that time. It is possible to calibrate or check whether it is within the tolerance range.

The above inspection _of each flowmeter _{M 1} , M _{2 , .} ...M _o-1 , M _o
can complete the inspection.

Of course, it is also possible to test only one specific flowmeter or a plurality of selected flowmeters.

Although one embodiment of the present invention has been described above, the sonic nozzles 2, 2'... provided in the reference flow rate generating chamber 1 may be replaced by other constant flow generating members, or vacuum pumps Instead, other vacuum sources may be used, and they may be connected to the tube body 6 on the upstream side of the chamber 1 as a pressure source such as a compressor. Furthermore, valves V ₁ and V ₂ , V ₃ and V ₄ ...
...V _o-3 , V _o-3 , and V _o-2 ... _o-1 and V _o may be used as three-way valves.

Furthermore, the configuration corresponding to the reference generation chamber 1 includes flow meters to be tested M ₁ , M ₂ , . . . M _o-1 ,
It may be installed on the upstream side of _Mo.

Next, all of the valves V ₁ , V ₂ . . . V _o can be controlled by electrical, pneumatic, or hydraulic control.

As described above, this invention allows one or more flowmeters to be connected to a pipe line that can selectively change the reference or standard flow rate at the same time, and the connection with the pipe line can be opened and closed using a valve switching mechanism. In particular, accuracy tests in the micro flow range of flowmeters, which require a small flow rate of a pilot flame to be applied to a large flow rate such as a gas meter, were conventionally performed for each individual flow meter. However, according to the present invention, a large number of flowmeters are tested at the same time, which has the effect of shortening the time required for the test.

Further, since valve switching, reference flow rate selection, inspection calculations, etc. can all be performed centrally by the control device, various computers can also be used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a flowmeter inspection device according to the present invention, and FIGS. 2a and 2b are block diagrams showing an example of an inspection method of the same inspection device, and the relationship between pulse waveform and flow rate change. This is a graph showing. 1...Reference flow rate generation chamber, 6, 9...Pipe body, _V1 , _V3 ,...V _o-3 , V _o-1 ...Switching valve,
V′ ₂ , V ₂ , V′ ₄ , V ₄ , ...V′ _o-3 , V _o-3 , V′ _o-1 ,
V _o-1 ... Valve, M ₁ , M ₂ ... M _o-1 , M _o ... Flow meter for test, A ... Control device, F ... Fluid source, 11 ... Flow rate counter , 13... unit flow rate generation section, 14... time measurement section.

Claims (1)

[Claims] 1. A test flowmeter having an arbitrary number of unit flow rate generators is connected in series and selectably to a reference flow rate generating device that generates different reference flow rates, and the flow rate emitted from the unit flow generator of the test flowmeter is connected in series and selectably. In an inspection device that determines the accuracy of a flowmeter under test by comparing an integer multiple of the pulse interval with a reference flow rate flowing during this period, when testing a large flow rate range, the above unit flow rate of each flowmeter under test is means for storing the period of the flow rate pulse transmitted from the generating section; means for estimating the transmission position of the next flow pulse to be transmitted in the unit flow rate generating section from the stored period; and a minute position before the estimated position. 1. A flowmeter inspection device comprising: means for stopping the unit flow rate generation section at a time of 0, and means for starting inspection of a small flow rate with a large pulse interval after all unit flow rate generation sections have been stopped.