JPS6229927Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a control device for abnormality detection that can prevent various types of equipment using sonic nozzles from being damaged or damaged due to the flow of more than necessary airflow.

In recent years, sonic nozzles have come to be used for measuring the flow rate of various gas devices and for calibrating and testing gas flowmeters because they maintain a constant sonic flow in a critical region.

Moreover, this sonic nozzle is already used in the form of a plurality of two or more installed, and it is common that they are selectively opened and closed by a valve control mechanism and used for measurement under the required gas flow. It is true.

When using a nozzle chamber having a configuration in which a plurality of sonic nozzles are arranged in this way, the valve control mechanism that opens and closes the sonic nozzles may not be able to perform reliable control at times. For example, when all the valves are open and a large flow rate flows even though the measurement is to be performed at a small flow rate, this may cause damage to the gas equipment to be tested and other meter equipment.

Therefore, in order to eliminate such inconveniences, this invention first examines whether or not the valve control mechanism that opens and closes the sonic nozzle is in an appropriate state before or during the operation of the gas flow generation source to generate the gas flow. It is an object of the present invention to provide an abnormality detection control device for a gas flowmeter system using a sonic nozzle, which can be checked and immediately stop the operation of a gas flow source if an abnormality occurs during operation.

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

Reference numeral 1 denotes a nozzle chamber in which two or more sonic nozzles 2 having the same or different capacities are disposed on a partition wall 3, forming a front chamber 5 having an inlet 4 and a rear chamber 7 having an outlet 6. Reference numeral 8 denotes a valve control mechanism that opens and closes the sonic nozzle 2 described above with a valve 9, and is composed of an air cylinder 8a provided outside the rear chamber 7 and a piston rod 8b operated by an air piston, and a valve 9 is installed at the tip of the piston rod 8b. It is provided. The valve control mechanism 8 includes a switching valve 14 1 which opens and closes the valve by switching the gas flow path of each air cylinder 8a from a driving source 10 such as an air source via a filter 11, a pressure reducing valve 12, and a lubricator ₁₃ . 14 ₂ , 14 ₃ , . . . are connected by a conduit 15. Now, in the illustrated state, the switching valves 14 ₁ and 14 ₂ are switching the gas flow path in the direction of closing the sonic nozzle ₂ from the piston rod 8b to the valve 9. The gas flow path is switched in the open direction. In particular, the closing force of the valve 9 against the sonic nozzle 2 is related to the magnitude of the driving force such as the air pressure applied to the piston 8b of the air cylinder 8a.

Reference numeral 16 denotes a pressure gauge installed in the middle of the pipe line 15, which can issue an alarm signal when the pressure reaches a certain level or lower. Reference numeral 17 denotes an abnormality detection mechanism, such as an electrical control operation circuit, which connects the switching valves 14 ₁ , 14 ₂ ,
14 ₃ ... and is electrically connected to the pressure gauge 16.

Reference numeral 18 denotes a gas flow line that includes the nozzle chamber 1, and is designed to allow a necessary gas flow to flow through a gas flow source such as a compressor or a vacuum pump 19 as shown. A desired test object, such as the test gas flowmeter 20, is connected to the upstream side (or flow side). 21
are safety emergency shutoff valves provided in necessary numbers on the inflow side and outflow side of the gas flow meter 20 to be tested in the line 18 or in the vicinity of the gas generation source 10, which are opened and closed by the command of the abnormality detection mechanism 17. I'm starting to do that. Note that the abnormality detection mechanism 17 is a vacuum pump 19.
It is now possible to control vacuum sources such as Reference numeral 22 denotes a valve operation mechanism, which includes a valve control mechanism 8, a drive source 10, a control valve 14, a pipe line 15, and a control operation circuit 17. In the above embodiment, the drive source 10 is described as an air source, but it goes without saying that a hydraulic source, an electric source, or the like may be used instead.

Note that this abnormality detection mechanism 17 can also be incorporated as a computer control in combination with various verification circuits or a compensation circuit for the sonic nozzle 2.

The operation of this device will be explained based on the above structure.

First, a starting operation is performed by the abnormality detection mechanism 17, and the desired switching valve ₁₄₂ is operated to open the valve 9 as shown in the figure, and the other control valves ₁₄₁ and ₁₄₃ are not operated and the valve 9 is closed. Let me keep it.

In this state, the driving pressure inside the pipe line 15 is measured by the pressure gauge 16.
is displayed and transmitted to the abnormality detection mechanism 17, which calculates whether the pressure is appropriate or not. After confirming that the pressure is appropriate, the gas flow source 1 such as a vacuum pump
9 to open the emergency shutoff valve 21.

In this way, when starting the vacuum pump 19, the abnormality detection mechanism 17 always determines whether or not the driving pressure acting on the valve 9 is appropriate, so the valve 9, which was closed, will open due to insufficient driving pressure. Conventional inconveniences such as this are avoided.

In addition, even if the driving pressure decreases during operation of the gas flow source 19 such as a vacuum pump, this driving pressure is constantly detected by the pressure gauge 16, so if an abnormal situation occurs, the abnormality detection mechanism 17 is immediately issued. emergency shutdown of the gas flow source 19 such as a vacuum pump, etc.
By quickly closing the emergency shutoff valve 21, the safety of the gas flowmeter to be tested can be ensured.

As mentioned above, this device is designed so that abnormalities can be detected at any time before or during the operation of the gas flow source when the valve of the sonic nozzle is closed. It is possible to avoid this and maintain the operating state under constant gas flow.

Furthermore, in the event of an abnormal situation, the abnormality detection mechanism can be used to stop the operation of the gas flow source and automatically close the emergency shutoff valve installed in the line, allowing various equipment, especially those under inspection, to be stopped automatically. This has the effect of ensuring the safety of gases, such as flow meters, etc.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of an abnormality detection control device for a gas flowmeter system using a sonic nozzle according to the present invention. 1... Two or more sonic nozzles, 8... Valve 9, air cylinder 8a and air piston 8
a pulse mechanism consisting of b, 10...a driving source, 14
₁ , 14 ₂ , 14 ₃ ... switching valve, 15 ... pipe line,
16...Pressure gauge, 17...Abnormality detection mechanism, 18...
...Gas distribution line, 19...Vacuum pump, 20
...Test gas flowmeter, 21...Emergency shutoff valve.

Claims (1)

[Claims for Utility Model Registration] (1) A front chamber of a nozzle chamber partitioned by the partition wall, which is provided with a partition wall equipped with a plurality of sonic nozzles with known flow rates and a valve control mechanism for selectively opening and closing the sonic nozzles. A flow rate test device and a vacuum pump are connected in communication with each other in the rear chamber, and the flow rate of the flow rate test object is compared with the flow rate based on the selected sonic nozzle, and the fluid that drives the valve control mechanism is An abnormality detection control device for a gas flowmeter system using a sonic nozzle, which detects pressure and shuts off a flow path of a flow rate object and/or a vacuum pump at a pressure outside a specified range. (2) Anomalies in the gas flowmeter system using a sonic nozzle as set forth in claim 1, wherein the valve control mechanism for opening and closing the sonic nozzle is configured using pneumatic pressure, hydraulic pressure, water pressure, or other liquid pressure. Detection control device.