JPH0612285B2 - Flowmeter calibration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention calibrates the measured value of a flow meter provided in a conduit for flowing a highly toxic fluid or a fluid having a high vapor pressure in situ using an actual liquid. For equipment.

[Prior Art] As shown in FIG. 2, a flow meter for measuring the flow rate of a passing fluid is provided with a flow meter 3 in a pipe line 2 connected to a reference tank 1 and sent from the reference tank 1. The relationship between the flow rate per unit time and the number of pulses counted by the flow meter 3 was obtained, and calibration was performed based on this relationship.

[Problems to be Solved by the Invention] However, the actual flow coefficient of the fluid flowing in the pipeline connected to the equipment tank or the like may change depending on the arrangement and arrangement of the pipes at the time of installation, If the fluid used is different from the one used for calibration, the density and viscosity of the fluid will naturally differ, and the density will change when pressure is applied to the passing fluid. There are problems that arise and in these cases the flowmeter needs to be recalibrated again.

The present invention was devised to solve the above problems, and its purpose is to calibrate a flowmeter that can easily and highly accurately calibrate a flowmeter installed in equipment piping under actual equipment conditions using actual liquid. To provide a device.

[Means for Solving the Problems] In order to achieve the above object, the present invention relates to an apparatus for calibrating a measurement value of a flow meter provided in an equipment pipeline, in which a liquid passing through the flow meter is A catch tank with a closed structure for receiving once, a Venturi tube interposed in the pipeline connecting this catch tank and the equipment pipeline, and an electronic platform scale for measuring the weight change amount of the catch tank due to liquid inflow It is characterized in that calibration data is obtained from the measured value of the electronic platform scale and the measured value of the flowmeter.

[Operation] According to the calibration device of the present invention configured as described above,
The liquid that has passed through the flow meter is guided to the catch tank through the pipe line provided with the Venturi pipe. During that time, the flow meter measures the flow rate of the liquid passing through itself to the catch tank. On the other hand, the electronic platform scale measures the weight increase amount of the catch tank due to the liquid inflow. Since the amount of liquid measured by the electronic platform scale is the correct amount of liquid that should be originally measured by the flow meter, accurate calibration data can be obtained from the measured value of the electronic platform scale and the measured value of the flow meter.

With the closed structure of the catch tank, even in equipment that handles toxic liquids or fluids with high vapor pressure, the flowmeter installed in the equipment pipeline can be calibrated using actual liquid under actual equipment conditions. . In this case, the pressure in the catch tank rises due to the inflow of the liquid, but since the Venturi pipe is provided in the middle of the pipeline connecting the catch tank and the equipment pipeline, the flow rate is independent of the pressure change on the downstream side. Kept constant,
Accurate calibration data can be obtained.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 4 is an equipment tank for storing a fluid, 5 is a pipe line connected to the equipment tank 4 for supplying / discharging the fluid to / from the equipment tank 4, and 3 is interposed in the pipe line 5 to measure a flow rate. It is a flow meter.

As shown in the figure, the pipeline 5a between the flowmeter 3 and the equipment tank 4 and the pipeline 5b downstream from the flowmeter 3 (upstream indicates the equipment tank 1 side) are provided with on-off valves 6a and 6b, respectively. The branched pipes 7 and 8 are connected.

Now, in this embodiment, the calibration device for the flow meter 3 is configured as follows.

First, an electronic platform scale 10 for electrically measuring the weight of a load is integrally provided on a freely movable carriage 9, and the electronic platform scale 10 is installed.
A catch tank 11 as a load is installed on the top, and the catch tank 11 is integrally fixed to the electronic platform scale 10. One end of a forked supply / discharge pipe line 12 for supplying / discharging a fluid is integrally attached to the bottom portion 11a of the chatter tank 11,
A venturi pipe 13 is provided in the inflow-side supply / discharge pipe 12a, and an opening / closing valve 14 is provided in the return-side supply / discharge pipe line 12b. The other end 15 of the supply / discharge pipe 12b on the return side and the end 16 of the branch pipe 7 on the upstream side
Is connected by a return pipe line 18 which has joint compressors 17 at both ends and is made of a material having excellent pressure resistance, chemical resistance performance and flexibility performance.
The other end 19 of 2a and the end of the downstream branch conduit 8 are connected by an inflow conduit 21 configured similarly to the return conduit 18.

The catch tank 11 has a vent line 22 at its upper portion.
And, the pressurizing pipe line 23 for guiding the pressurizing fluid to pressurize the inside of the catch tank 11 is connected, and the vent pipe line 22 and the pressurizing pipe line 23 are provided with open / close valves 24 and 25. A vent pipe 22 is connected to a relief pipe 27 having a safety valve 26 connected to the front and back of an on-off valve 25.

On the other hand, a controller 28 is connected to the flow meter 3 and the electronic platform scale 10.

The controller 28 issues a trigger signal at the time when the flow rate change in the supply / discharge pipe 12a on the inflow side reaches a stable steady flow rate, sends a weight integration start command for the electronic platform scale 10 and sends a pulse count command to the flow meter 3. In addition to the configuration, a trigger signal is again issued after a lapse of a certain time from the command to stop weight integration and pulse counting.

Next, the operation will be described.

First, the on-off valves 14, 24, 25 are closed and the supply / discharge pipe 12b, the vent pipe line 22, and the pressurizing pipe line 23 are fully closed on the return side, and the measurement time of the controller 28 is set. Then, after pressurizing the equipment tank 4 to a certain level, the on-off valve 6b is opened to supply the fluid in the equipment tank 4 to the inflow conduit 21. The fluid passes through the Venturi tube 13 and enters the catch tank 11.

When the flow rate of the fluid sent to the catch tank 11 is stable (after about 10 seconds), the manual start button (not shown) of the controller 28 is pressed to start the pulse counting, and when the pulse counting stops, the on-off valve 6
Close b.

These operation procedures are repeated until the catch tank 11 is full.

Next, the on-off valves 14, 24, 25 are fully opened to return the fluid in the catch tank 11 to the equipment tank 4, the pressure of the equipment tank 4 is reset, and then the above operation procedure is repeated again.

Since the flow rate K factor per count pulse of the controller 28 can be obtained from the above operation, it was obtained.
Calibrate flowmeter 3 with K factor.

Therefore, the flow meter 3 of the installed pipeline 5 can be accurately calibrated without being influenced by the type of fluid flowing through the pipeline 5, pressure conditions, etc., and can be calibrated in a closed system. Even if the fluid is highly toxic, it will not leak to the outside and safety can be secured.

The on-off valves 6a, 14, 24 and 25 are connected to the controller 28
It is of course possible to use a solenoid valve controlled by, and input a steady flow rate signal from the flow meter 3 to the controller 28 to execute the above operation procedure.

[Effects of the Invention] As is clear from the above description, the calibration device of the present invention can easily and highly accurately calibrate the flowmeter provided in the equipment pipe under actual equipment conditions using actual liquid. Exerts an excellent effect.

[Brief description of drawings]

FIG. 1 is an apparatus diagram showing a preferred embodiment of the present invention, and FIG. 2 is a schematic diagram showing a calibration method for a conventional flowmeter. In the figure, 3 is a flow meter, 4 is an equipment tank, 5 is a pipeline, 9 is a trolley, 10 is an electronic platform scale, 11 is a catch tank, 13 is a venturi tube, 18 is a return pipeline, 21 is an inflow pipeline, 22 Is a vent line, 23 is a pressurizing line, and 28 is a controller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Sato 229 Tonogaya, Mizuho-cho, Nishitama-gun, Tokyo Inside Ishikawajima Harima Heavy Industries Ltd. Mizuho factory (72) Inventor Koichi Miyoshi 229 Tonogaya, Mizuho-cho, Nishitama-gun Tokyo 229 Ishikawajima Harima Heavy Industries Co., Ltd. Mizuho Plant (56) Bibliographic references Sho 61-155736 (JP, U)

Claims (1)

[Claims] 1. A device for calibrating a measurement value of a flow meter provided in an equipment pipeline, which has a catch tank having a closed structure for temporarily receiving the liquid that has passed through the flow meter, and the catch tank. The venturi pipe provided in the pipeline connecting the equipment pipeline and an electronic platform scale for measuring the amount of weight change of the catch tank due to liquid inflow are provided, and the measured value of the electronic platform scale and the flow meter A flowmeter calibration device characterized in that calibration data is obtained from measured values.