JP3411395B2 - Ventilation measurement 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 ventilation measuring apparatus for measuring the ratio of air that permeates from a part of the side of a sample when a specified amount of air is sucked from the end of the sample, The present invention relates to a ventilation measuring device that automatically measures an air inflow rate from a cigarette paper or a filter portion.

[0002]

2. Description of the Related Art Conventionally, a ventilation measuring apparatus of this type is shown in FIG. 6, for example, and an airtight container 1 for holding a sample (cigarette) A is an upper guide 1a, an upper support 1b, a first support 1b. It is composed of an airtight chamber 1c, a lower support 1d, a stopper 1e, a second airtight chamber 1f, a lower pipe 1g and a closing means 1h.
It is for automatic measurement that automatically holds and discharges.

Holders 1i and 1j for holding the upper support 1b and the lower support 1d, respectively, are provided on the outer circumferences of the upper support 1b and the lower support 1d, and the upper support 1b is provided.
And the lower support 1d form a space 1k between the retainers 1i and 1j. Further, this space 1k is connected to the pipe 2a.
Is connected to the three-way valve 2b via one side, one side is connected to the atmosphere and the other side is connected to the vacuum source 2.

The upper support 1b and the lower support 1d are made of a flexible material, and a hole smaller than the diameter of the sample A is formed in the center thereof, and the sample A is usually passed through this hole. Supports the sample and has a structure in which air is impermeable to the side surface of the sample.

Then, by operating the three-way valve 2b with a control unit (not shown), the pressure in the space 1k is changed to swell the upper support 1b and the lower support 1d into the space 1k, respectively. The diameter of the central hole provided in the lower support 1d can be changed.

Further, the stopper 1e is arranged below the central hole of the lower support 1d, and can receive the sample A falling from the upper side when the stopper cylinder 1e-1 is turned ON to move forward. On the other hand, when the stopper cylinder 1e-1 is turned OFF and retracted, the sample A is provided so as not to interfere with the downward dropping.

The lower pipe 1g provided in the lower portion of the airtight container 1 is made of a flexible material.
When the closing means 1h provided so as to face each other in the middle of the path moves forward due to "ON" of the closing cylinder 1h-1, the lower pipe 1
A second airtight chamber 1f is formed between the lower support 1d and g. Further, the closing means 1h is the closing cylinder 1h.
The lower pipe 1g returns to its original shape when retracted due to "OFF" of -1.

A critical nozzle 3 is connected to the second hermetic chamber 1f, and the critical nozzle 3 is connected to a vacuum source 2. A flow meter 5 is connected to the first hermetic chamber 1c.

With the above structure, during measurement, the stopper 1e is moved forward and the three-way valve 2b is operated to evacuate the space 1k to make the diameter of the central hole of the upper support 1b and the lower support 1d the sample. The sample A is dropped from the upper guide 1a, and the sample A is received by the stopper 1e through the central holes of the upper support 1b and the lower support 1d.

Then, the three-way valve 2b is operated to bring the inside of the space 1k to atmospheric pressure to narrow the central holes of the upper support 1b and the lower support 1d to hold the sample A and the stopper 1e.
And the lower pipe 1g is sandwiched by the closing means 1h. As a result, the first airtight chamber 1c and the second airtight chamber 1f are sealed.

When the first airtight chamber 1c and the second airtight chamber 1f are hermetically closed in this manner, a specified amount of air always flows in the second airtight chamber 1f to which the critical nozzle 3 is connected, while Since the sample A is a material having air permeability at the upper end and a part of the side, air flows at a constant rate due to the difference in ventilation resistance. Since the flowmeter 6 is connected to the first airtight chamber 1c in which a part of the side of the sample is confined, the amount of air flowing in from the side of the sample A can be measured.

When the measurement of the air flow rate is completed, the outer peripheries of the upper support 1b and the lower support 1d are evacuated again to release the detection A, and the closing means 1h is retracted so that the lower pipe 1g has a predetermined shape. Then, the sample A is dropped and discharged from the airtight container 1.

[0013]

However, as the flow meter 6 of such a device, a thermal type with a very small pressure loss is used, and this type of flow meter has a sensor part of dust. Since it is weak against adhesion and is affected by the temperature and humidity of the air, the installation location of the measuring instrument is limited,
There is a problem that the reliability of the measurement results cannot be guaranteed unless it is a place where air conditioning is always performed.

An object of the present invention is to provide a ventilation measuring device which can obtain a reliable measurement result even if the flow meter is affected by the environment.

[0015]

The ventilation measuring apparatus of the present invention made to solve the above-mentioned problems includes a first hermetic chamber for confining a part of a side portion of a sample and a second airtight chamber for confining one end of the sample. An airtight chamber, a critical nozzle capable of flowing a fixed volume of air that does not enter the sonic region under a fixed pressure, and a flow meter for measuring the flow state of the air, and the flow meter and the first Ventilation in which piping paths are respectively formed between the airtight chamber, the second airtight chamber and the critical nozzle, and the flow rate of air passing through a part of the side portion of the sample is measured from the output value of the flowmeter. A measuring device, wherein a three-way valve is provided between the first airtight chamber and the flowmeter, and between the second airtight chamber and the critical nozzle, and each one-way valve of the three-way valve is connected to operate the three-way valve. The flow meter The first state in which the flow meter is closed and the second state in which a pipe path that directly connects the flow meter and the critical nozzle are formed are switched, and the first output value of the flow meter in the first state and the second state. The calibration curve in the flow meter is calibrated based on the second output value of the flow meter in.

[0016]

In the ventilation measuring device of the present invention,
The first output value in the first state is an output value when the flow rate of the air flowing through the flow meter is 0, and the second output value in the second state is when the flow rate of the air flowing through the flow meter depends on the critical nozzle. This is the output value at a specified constant flow rate. Therefore, by calibrating the calibration curve of the flowmeter from the first output value and the second output value, the influence of the environment of the flowmeter can be corrected.

When a flow meter having a linear relationship between the flow rate of air flowing through the flow meter and the output value is used, the calibration curve of this flow meter is calculated from the first output value and the second output value. It can be easily obtained as a calibration line.

Further, the abnormality of the flow meter may be determined by comparing the first output value, which is the output value when the air flow rate is known, and the second output value with each specified value. it can.

[0019]

FIG. 1 is a view showing a ventilation measuring apparatus according to an embodiment of the present invention. Elements similar to those of the conventional apparatus are designated by the same reference numerals as those in FIG. 6, and detailed description thereof will be given. Omit it.

In the figure, 4 and 5 are three-way solenoid valves, one end of the critical nozzle 3 is connected to a three-way solenoid valve 4 via a pipe 3a, and one end of the three-way solenoid valve 4 is a pipe 4a.
Is connected to the second airtight chamber 1f via the, and the other end is connected to the flow meter 6 via the pipe 4b.

On the other hand, the first hermetic chamber 1c is connected to a three-way solenoid valve 5 via a pipe 5c. One end of the three-way solenoid valve 5 is a pipe 4a by a pipe 5a and the other end is a pipe 4b by a pipe 5b. Each is connected.

The control unit 10 is composed of a microcomputer or the like, and controls measurement based on a control program stored in a memory (not shown). Three-way solenoid valve 2
ON / OFF of b, 4, 5, the stopper cylinder 1e-1, the closing cylinder 1h-1, etc. is switched by a control signal output from the control unit 10. Further, the operation / display panel 20 performs input of measurement operation, measurement result, display of flowmeter abnormality, and the like.

Here, the three-way solenoid valves 4 and 5 are operated by electromagnetic force, and are turned on / off by a power source (not shown) by a control signal from the control unit 10, and the pipes shown by the solid line in FIG. Switch the route. Thereby, the control unit 10 calibrates the calibration curve of the flow meter 6 before the ventilation measurement.

That is, when neither of the three-way solenoid valves 4 and 5 is energized, that is, when it is "OFF", as shown in FIG.
A predetermined air amount (17.5 cc / sec in this embodiment) generated in the critical nozzle 3 which is always in a vacuum state, whose piping path is configured as shown by the solid line in (A), is a three-way solenoid valve from the piping 5c. 5 and the pipe 4a are joined together to flow to the three-way solenoid valve 4, while the three-way solenoid valves 5 and 4 are both blocked by the flow meter 6 and the flow meter 6 is in the state of zero flow (first 1 state). At this time, the output voltage e1 (first output value) of the flow meter 6 is obtained.

As shown in FIG. 2B, when only the three-way solenoid valve 4 is turned on, the pipe 4a is closed and the pipe 4
b is released, and the flowmeter 6 provided at the end of the b is electrically connected to the critical nozzle 3. As a result, the flow meter 6 has 17.5 cc.
/ Second is reached (second state), and at this time, the output voltage e2 (second output value) of the flow meter 6 is obtained.

In this way, the relationship between the output voltage e and the flow rate X is calculated based on the output voltage e1 when the flow rate of the flow meter 6 is 0 and the output voltage e2 when the flow rate is 17.5 cc / sec. The calibration curve shown can be determined.

When carrying out the measurement, as shown in FIG. 2 (C), the detection A is set in the first airtight chamber 1c and the second airtight chamber 1f, and the lower pipe 1g is sandwiched by the closing means 1h. , The three-way solenoid valve 4 "OFF", the three-way solenoid valve 5 "ON", flow meter 6 → three-way solenoid valve 5 → first airtight chamber 1c → sample A → second airtight chamber 1f → three-way solenoid valve 4 → A piping path is formed like the critical nozzle 3.

In this state, the air passing through the flowmeter 6 passes through the pipe 5b, the three-way solenoid valve 5, the first airtight chamber 1c connected to the pipe 5c, and flows from the side of the specimen A.
On the other hand, air can also flow in from the upper end of the specimen A in the axial direction, and the air merged in the specimen A passes from the lower end of the specimen A through the second hermetic chamber 1f to the pipe 4a and the three-way electromagnetic field. It flows into the critical nozzle 3 via the valve 4.

Since the amount of air passing through the critical nozzle 3 is constant at 17.5 cc / sec, the flow rate of how much air flows in from a part of the side of the sample with respect to this reference flow rate is determined. It can be measured from the output of the total 6.

Here, the flow meter 6 of this embodiment is of a thermal type as shown in FIG. That is, the two resistance wires 6 are connected to the pipe 6a for flowing the gas (air) to be measured.
b and 6c are wound and covered with a heat insulating material, and the resistance wires 6b and 6c
The output voltage e of the bridge circuit 6d including is output as a measured value.

Such a flow meter 6 has a high linearity between the flow rate and the output voltage, and the calibration curve can be obtained as a calibration straight line as shown in FIG. That is, the output voltage e
The following equations (1) and (2) are solved from 1, e2 to obtain the counts α and β, and the calibration straight line of the output voltage e and the flow rate X is obtained as the following equation (3).

17.5 = α · e2 + β (1) 0 = α · e1 + β (2) X = α · e + β (3)

FIG. 5 is a flow chart showing the control of the control unit 10, and an example of the control of the ventilation measurement will be described with reference to FIG. First, in step S1, the three-way solenoid valves 4 and 5 are both turned "OFF" to close the flow meter 6 as shown in FIG. 2A, and in step S2 the output value e1 of the flow meter 6 is read and stored. Next, in step S3, the output value e1
Is compared with a specified value to determine whether the output value e1 is within a predetermined range. If the output value e1 is within a certain range, the process proceeds to step S4, and if not within the certain range, step S11.
The flowmeter abnormality is displayed with and the process ends.

At step S4, the three-way solenoid valve 4 is turned "O".
2B, the critical nozzle 3 is connected to the flowmeter 6 and the output value e2 of the flowmeter 6 is read and stored in step S5. Next, in step S6, the output value e2 is defined. The output value e2 is compared with the value to determine whether or not the output value e2 is within a predetermined range. If the output value e2 is within a predetermined range, step S
7, the flowmeter abnormality is displayed in step S11 if the flow rate is not within the predetermined range, and the process ends.

In step S7, the three-way solenoid valve 4 is set to "OF".
F ", the three-way solenoid valve 5 is turned" ON "and the piping path is switched for measurement as shown in FIG. 2 (C), and in step S8, the output value e1, based on the above equations (1) and (2), is output. The coefficients α and β are obtained from e2, and the calibration straight line of equation (3) is calculated.

Then, in step S9, measurement processing such as sample supply, flow rate measurement, and sample discharge is performed, and step S9 is performed.
In 10, it is determined whether or not a predetermined number of samples have been measured. If the predetermined number is not reached, the process returns to step S9, and if the predetermined number is reached, the process ends.

As described above, the output value e1 when the flow meter 6 is closed and the flow rate of air is set to 0, and the flow meter 6 is directly connected to the critical nozzle 3 and a predetermined amount (17.5 cc in the embodiment).
Since the calibration straight line is obtained based on the output value e2 at the flow rate of / second), reliable measurement can be performed.

In the above embodiment, a flowmeter having a linear calibration curve is used. However, even if the flowmeter has a non-linear characteristic, the calibration curve is based on the known flow rate and the output value at that time in the same manner as above. By calibrating, it is possible to make reliable measurements.

Further, in the above embodiment, the abnormality is judged when at least one of the output value e1 and the output value e2 exceeds the specified value.
It may be determined to be abnormal when both the output value e2 and the output value e2 exceed their respective specified values.

Further, in the above embodiment, the calibration prior to the measurement is automatically performed under the control of the control unit 10, but may be performed manually or semi-automatically.

[0041]

As described above, according to the ventilation measuring apparatus of the present invention, the first airtight chamber and the flow meter for confining a part of the side portion of the sample, the second airtight chamber for confining one end of the sample, and the critical nozzle. A three-way valve is provided between the two, each of the three ports of the three-way valve is connected, and the flow meter is closed by operating the three-way valve.
The state and the second state in which a piping path that directly connects the flow meter and the critical nozzle is formed are switched, and the first output value of the flow meter in the first state and the second output of the flow meter in the second state Since the calibration curve in the flow meter is calibrated from the value and the flow meter, reliable measurement can be performed even if the flow meter is affected by changes in temperature and humidity and the environment such as dust.

[Brief description of drawings]

FIG. 1 is a diagram showing a ventilation measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating switching of piping paths according to an embodiment.

FIG. 3 is a circuit diagram of a flow meter in an example.

FIG. 4 is a diagram showing a calibration curve of a flow meter in an example.

FIG. 5 is a flowchart in the embodiment.

FIG. 6 is a view showing a conventional ventilation measuring device.

[Explanation of symbols]

1c ... 1st airtight chamber, 1f ... 2nd airtight chamber, 3 ... Critical nozzle, 4, 5 ... Three-way solenoid valve, 6 ... Flowmeter.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Obara 1-31 Kurobeoka, Hiratsuka-shi, Kanagawa Japan Tobacco Inc. Production Technology Development Center (56) Reference JP-A-61-56066 (JP) , A) JP 59-198962 (JP, A) JP 50-105898 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01F 25/00 A24C 5/34

Claims (3)

(57) [Claims] 1. A first airtight chamber for confining a part of a side portion of a sample, a second airtight chamber for confining one end of the sample, and a constant volume of air that cannot enter the sonic region under a constant pressure or less. And a flowmeter for measuring the flow state of air, the flowmeter, the first hermetic chamber, and the second
A ventilation measuring device which forms a pipe path between the airtight chamber and the critical nozzle, and measures the flow rate of air passing through a part of the side portion of the sample from the output value of the flowmeter, A three-way valve is provided between the first airtight chamber and the flowmeter, and between the second airtight chamber and the critical nozzle, and each one-way valve of the three-way valve is connected, and the three-way valve is operated to control the flow rate. The first state in which the meter is closed and the second state in which a pipe path that directly connects the flow meter and the critical nozzle are formed are switched, and the first output value of the flow meter in the first state and the first value A ventilation measuring device characterized in that a calibration curve in the flowmeter is calibrated from the second output value of the flowmeter in two states. 2. The flowmeter has a linear relationship between a flow rate of air flowing through the flowmeter and an output value, and a calibration straight line obtained from the first output value and the second output value is the calibration curve. The ventilation measuring device according to claim 1, wherein 3. The first output value, the second output value,
The abnormality of the flowmeter is determined when the first output value and / or the second output value exceeds the specified value by comparing the specified values with each other. The ventilation measurement device according to claim 1 or claim 2.