JP3091671B2 - Liquid metering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic liquid metering device for repeatedly measuring various liquids to an arbitrary set amount.

[0002]

2. Description of the Related Art Conventionally, as a pneumatic liquid metering device, there is a device shown in FIG. In this apparatus, a flow meter 3 provided with a preset counter 5 and an automatic opening / closing valve 4 equipped with an opening / closing cylinder 4a are mounted in the pipe 2, and are self-held by the operation of a metering start valve 11 connected to an air source 8. The main switching valve 7 is switched by actuating the auxiliary switching valve 90 of the mold type, and pressurized air in the opening operation direction is supplied to the opening / closing cylinder 4a to open the automatic opening / closing valve 4, and the liquid to be measured in the pipe 2 is brought to a predetermined location. A supply air circuit is provided. The preset counter 5 is provided with a micro-valve 6 which is always shut off. When the micro-valve 6 is operated by a signal from the preset counter 5, the preset counter 5 is brought into a communication state and the auxiliary switching valve 90 is turned off. The pilot unit 90 a is connected to supply compressed air from the air source 8 via the shuttle valve 10. In this liquid metering device, the auxiliary switching valve 90 is switched by the operation of the metering start valve 11, the automatic open / close valve 4 is opened, and the metering of the liquid to be measured is started. Accordingly, the flow meter 3 measures the flow rate of the liquid to be measured, and when the flow rate reaches the set value of the preset counter 5, a signal is sent to the microvalve 6 to operate the microvalve 6 to establish a communication state. As a result, the compressed air is supplied to the pilot portion 90a of the auxiliary switching valve 90, and the auxiliary switching valve 90 is moved back to the main switching valve 7a.
Of the pressurized air to the pilot section 7a is cut off.
For this reason, the main switching valve 7 is moved back, air in the closing operation direction is supplied to the opening / closing cylinder 4a of the automatic opening / closing valve 4, and the automatic opening / closing valve 4 is closed, so that quantitative measurement is reliably performed.

[0003]

In this liquid metering device, the pressure air of the air source 8 is significantly reduced due to a power failure or abnormality during the measurement, and the pilot portion 90a of the main switching valve 90 is operated.
When the force for pressing is weakened, the main switching valve 7 returns by self-return and returns to a state in which air in the closing direction is supplied to the opening / closing cylinder 4a. At this time, although the emergency shutoff valve (not shown) in the pipe is operated, the automatic on-off valve 4 is closed or kept open according to the reduced pressure of the compressed air. In this state, when the air source 8 is restored and the pressure of the pressurized air returns to the predetermined pressure and the emergency shutoff valve is opened, the auxiliary switching valve 90 maintains its operating state by itself. Pressurized air is supplied to the pilot section 7a. Therefore, the main switching valve 7 is operated again,
Air in the opening operation direction is supplied to the opening / closing cylinder 4a, the automatic opening / closing valve 4 is opened, and the liquid to be measured in the pipe 2 flows again. At this time, if the pipe 2 is abnormal and the pipe 2 is removed for inspection, there is a risk that the liquid to be measured touches the worker or overflows from the tank. There is a need for a high liquid metering device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned demands, and an object thereof is to provide a liquid metering device capable of restarting a metering operation safely even if the pressure of the air from the air source decreases during metering. Is what you do.

[0005]

A flow meter provided with a preset counter and an automatic open / close valve are disposed in a pipe through which a liquid to be measured flows, and an air source is connected to an open / close cylinder of the automatic open / close valve via a main switching valve. While providing an air circuit connected to an air source via an auxiliary switching valve at the pilot portion of the main switching valve, a micro valve is attached to a preset counter, and the micro valve is arranged in the air circuit,
The auxiliary switching valve is switched by the metering start valve to open the automatic on-off valve, the micro valve is operated by the signal of the preset counter, the auxiliary switching valve is moved back, and the automatic on-off valve is closed to perform the quantitative measurement of the liquid to be measured. In the liquid metering device to be performed, the auxiliary switching valve is of an automatic return type, and the pilot portion thereof is supplied with pressure air supplied by the operation of the metering start valve via the shuttle valve and pressure air supplied by the operation of the auxiliary switching valve. The air circuit which supplies either of them is provided.

[0006]

In the above liquid metering device, after the micro valve in the preset counter is brought into the communicating state, the auxiliary switching valve is switched by the operation of the metering start valve, and then the main switching valve is switched. Therefore, pressure air is supplied from the air source to the open / close cylinder of the automatic open / close valve, and the automatic open / close valve is opened,
The liquid to be measured in the pipe is supplied to a predetermined location. At the same time, the liquid to be measured in the pipe is measured by a flow meter, and when the flow rate reaches a preset value, a preset counter is operated and a signal is sent to the micro valve to shut off the micro valve. Therefore, the pressure air sent to the pilot portion of the auxiliary switching valve through the micro valve is shut off, and the auxiliary switching valve automatically returns, and then the main switching valve automatically returns. The air is supplied, the automatic on-off valve closes, and the quantitative measurement operation is completed.

[0007] During this time, if the pressure of the compressed air of the air source decreases for some reason such as a power failure, the auxiliary switching valve and the main switching valve in the switched state automatically return. Therefore, the open / close cylinder of the automatic opening / closing valve is supplied with pressurized air in the closing operation direction for closing the automatic opening / closing valve. Become. At this time, the emergency shut-off valve is activated to stop the supply of the liquid to be measured, but when the pressure air of the air source returns to the predetermined pressure thereafter, the auxiliary switching valve has already returned automatically at this time. The pressurized air from the source is not supplied to the pilot portion of the main switching valve, and the main switching valve is maintained in an automatically reset state. In addition, since the pressure air in the closing operation direction is supplied to the automatic opening / closing valve, the automatic opening / closing valve is closed, and the liquid in the pipe does not flow out when the air source is restored.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a liquid metering device arranged in a pipe 2 through which a liquid to be measured flows. The liquid metering device 1 has a flow meter 3 mounted in a pipe 2 and an automatic opening / closing valve 4 equipped with an opening / closing cylinder 4a, and the flow meter 3 is provided with a bleed counter 5. . The preset counter 5 is provided with a pneumatic microvalve 6 which is actuated when the preset counter 5 is set so that the operating lever 6a is pressed to connect a second pneumatic circuit described later. It is configured. Also, the operating lever 6a of the micro valve 6
When the flow rate of the liquid to be measured reaches the set value of the preset counter 5, the signal is returned by a signal from the preset counter 5 to be in a cutoff state, and the second air circuit in which this is incorporated is cut off.

On the other hand, an opening / closing cylinder 4a of the automatic opening / closing valve 4 is connected to an air source 8 via a main switching valve 7, and the first switching valve 7 is switched to open / close the automatic opening / closing valve 4. Of the air circuit is configured. The pilot portion 7a of the main switching valve 7 is connected to an auxiliary switching valve 9. The pilot portion 9a of the auxiliary switching valve 9 is connected to an air source 8 via a shuttle valve 10 by a metering start valve 11a.
And one end of the micro valve 6 connected to the pilot portion 7a of the main switching valve 7 are connected to each other.
A second air circuit is configured to supply the compressed air to the pilot portion 9a of the auxiliary switching valve 9 to maintain the operating state even if the operation is automatically restored after the operation of 1. Further, a stop switching valve 12 is connected between the micro valve 6 and the shuttle valve 10. When the stop switching valve 12 is operated and opened, the pilot valve of the auxiliary switching valve 7 and the main switching valve 7 is opened. The supply of pressurized air to the section 7a is shut off, the main switching valve 7 moves back, and the automatic on-off valve 4 is closed.

[0010] The operation of the liquid metering device according to this configuration will be described. First, an air source 8 for supplying pressurized air having a predetermined pressure is operated, then a preset counter 5 is used to set a desired set value of the liquid to be measured, and then an operating lever 6a of a micro valve 6 is operated. 6 is kept conductive. In this state, the metering start valve 11
Is pressed, the air pressure of the air source 8 is
0 is supplied to the pilot portion 9a of the auxiliary switching valve 9 by the action of 0, and the auxiliary switching valve 8 is switched. As a result, the pressure air of the air source 8 is supplied to the pilot portion 7a of the main switching valve 7, and the main switching valve 7 is switched to supply the compressed air in the opening operation direction of the opening / closing cylinder 4a of the automatic opening / closing valve 4 to automatically operate. The on-off valve 4 opens. At the same time, the pressurized air supplied to the micro valve 6 of the preset counter 5 is supplied to the pilot portion 9a of the auxiliary switching valve 9 via the shuttle valve 10 after the metering start valve 11 automatically returns, and the auxiliary switching valve 9 is switched. It can be kept in the state.

In this state, when the liquid to be measured in the pipe 2 is supplied to a predetermined location, the flow rate of the liquid to be measured is measured by the flow meter 3, and when the flow rate reaches the set value of the preset counter 5, A signal is sent from the preset counter 5 to the microvalve 6, and the operating lever 6a of the microvalve 6
Is restored, and the microvalve 6 is turned off. Therefore, the supply of the pressurized air to the pilot portion 9a of the auxiliary switching valve 9 is stopped, and the auxiliary switching valve 9 and the main switching valve 7 subsequently automatically return. Therefore, the opening / closing cylinder 4a of the automatic opening / closing valve 4
Is supplied in the closing operation direction, and the automatic on-off valve 4 is closed to complete the quantitative measurement operation.

During this time, if the pressure of the compressed air of the air source 8 decreases for some reason such as a power failure, the auxiliary switching valve 9 and the main switching valve 7 automatically return. The automatic opening / closing valve 4 operates according to the pressure of the compressed air at that time. To be closed or open. At this time, the emergency cutoff valve (not shown) is activated to stop the supply of the liquid to be measured in the pipe 2, but thereafter, the air source 8
Is restored and the pressure air returns to the predetermined pressure, the auxiliary switching valve 9 has already automatically returned, so the pressure air from the air source 8 is not supplied to the pilot portion 7a of the main switching valve 7,
The main switching valve 7 is kept in the restored state and does not operate again.
Also, with the restoration of the pressurized air, the automatic on-off valve 4
Is supplied with pressurized air in the direction to close it.
The automatic on-off valve 4 is closed, and the liquid to be measured in the pipe 2 does not flow out when the air source 8 is restored.

[0013]

As is clear from the above description, the present invention
A flow meter provided with a preset counter and an automatic opening / closing valve having an opening / closing cylinder are arranged in the pipe of the liquid to be measured, and an air source is connected to the opening / closing cylinder via a main switching valve,
Further, an air source is connected to the pilot portion of the main switching valve via an automatic return type auxiliary switching valve, while the work start valve is operated to supply compressed air from the air source to the pilot portion of the auxiliary switching valve and perform auxiliary switching. It is configured to supply the compressed air supplied from the valve to its own pilot section.
Therefore, even if the pressure of the compressed air drops due to a failure of the air source or the like and the main switching valve returns in a state where the automatic on-off valve is opened,
Depending on the pressure of the pressurized air at that time, the automatic on-off valve may be kept open. However, when the air source is restored and the pressure of the compressed air rises, the automatic on-off valve is immediately closed. Therefore, in the present invention, the liquid to be measured in the pipe does not suddenly flow out without the main switching valve being reactivated, and the liquid to be measured touches the worker during pipe inspection. Not only is there no danger, but also the danger of the measured liquid overflowing from the supply destination tank can be prevented, and safety can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a quantitative metering device of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional quantitative metering device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid metering device 2 Piping 3 Flowmeter 4 Automatic opening / closing valve 4a Opening / closing cylinder 5 Preset counter 6 Micro valve 6a Operating lever 7 Main switching valve 7a Pilot section 8 Air source 9,90 Auxiliary switching valve 9a, 90a Pilot section 10 Shuttle Valve 11 Measurement start valve 12 Switching valve for stop

Claims (1)

(57) [Claims] A flow meter provided with a preset counter and an automatic opening / closing valve are provided in a pipe through which a liquid to be measured flows, and an air source is connected to an opening / closing cylinder of the automatic opening / closing valve via a main switching valve. The pilot circuit of the main switching valve is provided with an air circuit connected to an air source via an auxiliary switching valve, while the preset counter is provided with a micro valve. This micro valve is arranged in the air circuit, and the auxiliary switching is performed by a metering start valve. In a liquid metering device that switches the valve to open the automatic on-off valve, activates the micro valve according to the signal of the preset counter, moves the auxiliary switching valve back, closes the automatic on-off valve, and performs quantitative measurement of the liquid to be measured. The auxiliary switching valve is of an automatic reset type, and the pilot air is supplied to the pilot section by the operation of the metering start valve via the shuttle valve and the operation of the auxiliary switching valve. And a pneumatic circuit for supplying any of the supplied compressed air.