JPS6152407B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flowmeter verification device, which enables accurate flowmeter verification at all times by controlling the pressure of liquid at the outlet side of the flowmeter to be verified to be constant. The purpose is to propose a device.

In general, as a flowmeter verification device, liquid pumped by a pump passes through the flowmeter and then flows into a reference tank whose volume value is known from the bottom of the tank, gradually raising the liquid level until the liquid level reaches the upper limit. There is an apparatus configured to verify the instrumental error of the flowmeter by stopping the pressure feeding of the liquid when the flowmeter reaches the position and comparing the amount of liquid transferred into the reference tank with the integrated flow rate indicated by the flowmeter. Verification using this reference tank method is advantageous in terms of accuracy because air bubbles do not get mixed into the liquid in the tank.

However, as the liquid level rises in the reference tank, the lift applied to the liquid pump increases, so the amount pumped by the pump gradually decreases. The drawback was that accurate testing could not be performed.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described below with reference to the drawings.

The figure shows a schematic configuration of an embodiment of a flow meter verification device according to the present invention.

The verification device is, for example, a flowmeter 1 such as a Roots meter.
is connected to pipe 2 and its instrumental error is verified using actual flow. When the pump 3 is started, the test liquid 6, which has been made to a predetermined viscosity by the heater 5 in the lower tank 4, is suctioned and pressure-fed into the piping 2, passes through the flow meter 1, and is further pumped into the reference tank 7 by the differential user 2a. The on-off valve 9 is opened by the solenoid valve 8 after the inflow speed is uniformly decelerated to reduce the ripples on the liquid surface and the liquid flows into the lower part of the reference tank 7.
The liquid then passes through the flow rate adjustment valve 10 and returns to the lower tank 4. In this case, the pressure at point A immediately after the flowmeter 1 is desirably constant during the verification period, and is set to be always, for example, pressure P, as described later.

An air source 11 supplies and applies air at a predetermined pressure into the reference tank 7 through a pressure reducing valve 13 through an air line 12 . Air source 11 is air pressure transmitter 1
4 through another air line 15 to a flow rate control valve 16 disposed in communication above the reference tank 7, and supplies air for adjusting the valve opening to this valve 16.

A pressure detection element 17 detects the fluid pressure at point A, and the detected pressure is converted into a signal and sent to the air pressure transmitter 14. As a result, the amount of air supplied to the air line 15 is controlled, and the opening degree of the flow rate regulating valve 16 is adjusted to be appropriate as described above. That is, if the pressure at point A is higher than the pressure P, the valve 16 is operated in the opening direction to reduce the pressure in the reference tank 7, and in the opposite case, the valve 16 is operated in the closing direction. The pressure in the reference tank 7 is increased and controlled so that the pressure at point A is always equal to pressure P.

Now adjust the flow rate control valve 10 to set the reference tank 7.
After adjusting the liquid level inside to position B, the solenoid valve 8 is switched to quickly close the on-off valve 9. At the same time, the control device 18 receiving the signal from the solenoid valve 8 issues a signal to the camera 19 with a strobe, and the camera 19
The integrated display flow value of the flow rate indicator 1a of the flow meter 1 at the start of the verification is photographed.

As a result, the liquid 6 enters the reference tank 7 and the liquid level rises, eventually reaching a position C where it contacts the liquid level detector 20. At this time, a signal is transmitted from the liquid level detector 20, and the control device 18 operates to send a signal to the strobe camera 19 again. Take a photo. At the same time, the control device 18 opens the on-off valve 9 via the solenoid valve 8, so that the liquid 6 flows into the lower tank 6 again. Further, while the liquid level reaches position C from position B, the liquid pressure gradually increases as the liquid 6 in the reference tank 7 increases, and conversely, the liquid pressure increases as the liquid 6 in the reference tank 7 increases.
The air pressure inside is controlled to gradually decrease, and the total pressure of both is always the above pressure P. Therefore,
During this period, the pressure at point A is maintained at the pressure P from beginning to end, so the liquid flow rate of the flowmeter 1 is also constant. Therefore, the flow rate of the flow meter 1 is determined by the amount of liquid filled until the liquid level of the reference tank 7 reaches position C from position B and the cumulative flow rate of the difference between the cumulative display flow values at the start and end of the verification of the flow rate indicator 1a. Accurate testing can be performed.

FIG. 2 shows a schematic diagram of another embodiment of the flow meter verification device of the present invention. In the figure, the same parts as those in FIG.

In this embodiment, a flow rate indicator 1a is attached to the flow meter 1 via an electromagnetic clutch 21 which is normally in a connected state and is in operation, and a switching valve 22 is provided at the rear of the flow meter 1 to allow liquid flow. The route is switched to either the reference tank 7 or the upper tank 23.

Before the verification, the valve stem 22a of the switching valve 22 is at the upper sliding limit, so the valve portion 22b is opened and the valve portion 2
Valve 2c is closed.

Therefore, the liquid 6 that has passed through the flowmeter 1 is sent upward through the pipe 24 through the valve portion 22b and into the upper tank 2.
It flows into 3. The liquid 6 is further sent downward through a pipe 25 and flows into the lower tank 4 via a flow rate control valve 26. The liquid 6 thus repeats this circulation, and the flow meter 1 rotates in a steady state. Further, the pressure of the liquid 6 at point A on the outlet side of the flowmeter 1 and near the switching valve 22 is always a pressure corresponding to the water head H (m) due to the action of the upper tank 23.

Next, the switching valve 22 is operated to switch the valve stem 22a.
is brought to the downward sliding limit as shown, the valve portion 22b is closed, and the valve portion 22c is opened. Then, as described above, the liquid 6 that has reached the switching valve 22 is transferred to the valve section 22.
c. It passes through the differential user 2a and returns to the lower tank 4 as described above.

Now adjust the flow rate control valve 10 to set the reference tank 7.
After the liquid level in the tank reaches position B, the on-off valve 9 is quickly closed. Then, the liquid 6 enters the reference tank 7 and the liquid level rises, and eventually the liquid level detector 20
reaches position C where it contacts. At this time, the liquid level detector 20
The valve stem 22 of the switching valve 22
Slide a upward in the figure. As a result, the valve part 2
2b is opened, and the valve part 22c is closed, so that the liquid 6 that has passed through the flowmeter 1 is stopped from flowing into the reference tank 7 side and flows into the pipe 24. Furthermore, the electromagnetic clutch 21 is simultaneously disengaged by the above signal from the liquid level detector 20, and the flow rate indicator 1a stops displaying the accumulated flow rate at the end of the verification, even though the flow meter 1 continues to operate. . Also, while the liquid level is moving from position B to position C, the air pressure in the reference tank 7 is adjusted based on the pressure measurement value of the pressure detection element 17 as in the first embodiment, and the flowmeter 1 is adjusted. The pressure at point A on the outlet side is always the water head pressure H (m)
The pressure is controlled to be equal to the pressure. Therefore, while the liquid level reaches from position B to C, the pressure at point A is always maintained at the water head H (m) as in the above embodiment, and therefore the liquid flow rate of the flowmeter 1 is constant. Therefore, depending on the liquid filling amount until the liquid level of the reference tank 7 reaches position C from position B and the flow rate displayed on the flowmeter 1, the flowmeter 1
An accurate test can be performed.

When switching the switching valve 22, since both the outlet side of the valve part 22b and the outlet side of the valve part 22c have a pressure head H (m), and there is no pressure difference on both sides of the valve 22,
The switching operation of the valve stem 22a can be performed easily and quickly, and an unsteady flow of the liquid 6 is unlikely to occur during the switching operation, making it possible to carry out the above-mentioned verification more accurately, and also preventing inconvenient phenomena such as water hammer from occurring. hard.

Further, in the first embodiment, it is only necessary to add the control devices 11 to 20, etc. to the conventional device, and in other embodiments, the switching valve 22, the tank 23, and the piping 2 are added.
4, 25, an electromagnetic clutch 21, etc., and can be easily modified.

As described above, according to the flow meter verification device of the present invention, the liquid that has passed through the flow meter is allowed to flow into the tank, and the actual amount of liquid measured in the tank is compared with the displayed flow rate indicated by the flow meter. A device for verifying the flowmeter by detecting the pressure of the liquid at the outlet side of the flowmeter, a pressure application means for applying pressure to the liquid in the reference tank, and an output signal of the detection means. a pressure control means that controls the applied pressure of the pressure application means so as to keep the pressure on the outlet side of the flowmeter constant according to the flow rate; Since the flow rate of the flowmeter is constant from beginning to end during the above-mentioned verification, the actual fluid flow rate and the displayed flow rate are not directly different from each other. This method has the advantage that it is easy to accurately verify the flowmeter through comparison, and that a conventional device can be easily modified and manufactured.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are schematic diagrams of one embodiment and another embodiment of the flow meter verification device according to the present invention, respectively. 1... Flow meter, 1a... Flow rate display meter, 2, 2
4,25...Piping, 3...Pump, 4,23...
Tank, 6...Liquid, 7...Reference tank, 8...
Solenoid valve, 9... Opening/closing valve, 10, 26... Flow control valve, 11... Air source, 12, 15... Air line, 13... Pressure reducing valve, 14... Air pressure transmitter, 1
6...Flow control valve, 17...Pressure detection element, 18
...Control device, 19...Camera with strobe, 20
...Liquid level detector, 21...Electromagnetic clutch, 22...
...Switching valve, 22a... Valve stem, 22d, 22c...
Benbe.

Claims (1)

[Claims] 1. In a device that certifies a flowmeter by making the liquid that has passed through the flowmeter flow into a tank and comparing the actual amount of liquid measured in the tank with the displayed flow rate indicated by the flowmeter, means for detecting the pressure of the liquid in the reference tank, pressure applying means for applying pressure to the liquid in the reference tank, and applying the pressure to keep the pressure on the outlet side of the flowmeter constant according to the output signal of the detecting means. pressure control means for controlling the applied pressure of the means;
actuated by a liquid inflow signal into the tank;
A flow meter verification device comprising a display flow rate reading means that stops operating when the liquid reaches a predetermined position in a tank.