JP4957599B2 - Gas introduction device - Google Patents

Description

  The present invention relates to a gas introduction device for introducing a predetermined gas into an analysis device, and more particularly to a gas introduction device for introducing a gas supplied in a pressurized state into the analysis device. The type of analyzer to which gas is introduced is not particularly limited, but as a typical analyzer, an odor measuring apparatus or a gas chromatograph for performing quantification or qualification of odor components in gas can be considered.

  As a gas introduction device for introducing a gas prepared in a sample container into various analyzers such as an odor measurement device and a gas chromatograph, a gas introduction device described in Patent Document 1 is conventionally known. This gas introduction device includes a rotary valve that selectively connects the suction and discharge ports of a syringe pump (piston / cylinder type pump) to the sample container side and the analysis device side. As a basic operation, first, the gas in the sample container is sucked and held in the syringe pump, and then the flow path is switched by the rotary valve, and the gas previously held in the syringe pump is discharged and introduced into the analyzer. .

  Using such a gas introduction device, for example, when it is desired to introduce gas stored in a high pressure container such as a calibration gas into the analyzer, the flow path is switched so that the syringe pump and the high pressure container are connected by a rotary valve. Gas pressure is applied to the syringe pump syringe. In many cases, the syringe is made of glass and may be damaged if excessive internal pressure is applied. Therefore, a method has been adopted in which a part of the gas supplied from the high-pressure container is released into the atmosphere, and the gas is sucked with a syringe pump while adjusting the gas pressure in the piping and syringe to about atmospheric pressure. Yes. This is a method called the overflow method.

  However, since this method consumes a large amount of gas in vain, there is a problem that the operating cost increases when the gas used is expensive. Further, there is no problem if a large amount of gas such as nitrogen gas exists in the atmosphere, but depending on the type of gas, it may not be desirable to release it into the atmosphere, and the overflow method cannot always be employed. Furthermore, in the overflow method, there is a possibility that the gas pressure in the pipe is excessively lowered, and there is a problem that outside air enters the pipe from a connection portion of the pipe and becomes an impurity.

Japanese Patent Laid-Open No. 2005-3387

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to within the allowable range of the pressure resistance of the syringe without wastefully consuming the gas supplied in a pressurized state. An object of the present invention is to provide a gas introduction device capable of suppressing gas pressure in a pipe and preventing outside air from being mixed.

The present invention made to solve the above problems is a gas introduction device for introducing a gas supplied to a pressurized gas supply port into an analyzer,
a) a syringe pump that takes in and discharges gas from the suction and discharge port by reciprocating movement of the plunger;
b) an inlet on / off valve provided in a flow path between the pressurized gas supply port and the suction / discharge port;
an intermediate-off valve provided in a flow path between the c) the entering port opening closed and the suction and discharge port,
d) an outlet on / off valve provided in a flow path between the suction / discharge port and a gas delivery port to the analyzer;
e) a buffer container part connected to a flow path between the inlet on-off valve and the intermediate on-off valve and having a variable volume and being pressurized from the outside in a direction in which the volume decreases;
It is characterized by having.

  The means for pressurizing (applying external pressure) to the buffer container portion is not particularly limited. For example, a weight, that is, means for applying pressure by using gravity, pressurizing by using elastic force or urging force of a spring or rubber, etc. A means for performing the above can be considered. In any case, a predetermined pressure that is larger than the atmospheric pressure and smaller than the gas pressure supplied to the pressurized gas supply port is applied to the buffer container by this pressurization.

  In the gas introducing device according to the present invention, high-pressure gas is supplied to the pressurized gas supply port, but there is a demand for the analyzer to send gas in a state as close to atmospheric pressure as possible. A buffer container part exists between a pressurized gas supply port and a gas delivery port, and has the effect | action of the buffer or pressure regulator which adjusts a gas pressure.

  In the gas introducing device according to the present invention, as the first stage, the inlet on / off valve is opened with the intermediate on / off valve closed. Then, since the supply gas pressure is larger than the external pressure of the buffer container part, the gas flows into the buffer container part. If a predetermined amount of gas is introduced into the buffer container, or if gas is introduced into the buffer container for a predetermined time corresponding to the predetermined amount, the inlet on / off valve is closed. At this time, the gas pressure in the flow path (pipe) between the inlet on-off valve and the intermediate on-off valve is substantially the same as the external pressure of the buffer container.

  After that, as a second stage, with the intermediate on-off valve opened and the outlet on-off valve closed, the plunger in the syringe pump is pulled to suck the gas in the buffer container into the syringe. Since the gas pressure in the flow path (pipe) when the intermediate open / close valve is opened depends on the internal volume of all the flow paths from the inlet open / close valve to the outlet open / close valve and the amount of gas stored in the buffer container part, The amount of gas to be stored is determined so that the gas pressure is slightly higher than the atmospheric pressure. After sucking the gas in the buffer container part into the syringe pump and holding it in the syringe, as a third stage, the intermediate on-off valve is closed, the outlet on-off valve is opened, and the plunger is pushed to move the gas from the gas outlet to the analyzer. And send it out.

  In the second stage, the reason for setting the gas pressure to be slightly higher than the atmospheric pressure is that if the gas pressure is high, the molar ratio of molecules in the gas held in the syringe becomes high, which hinders the accuracy of analysis. Because there are cases. Therefore, if there is no such problem, the gas pressure need only be in a range higher than atmospheric pressure and lower than the pressure resistance of the syringe.

  The series of operations as described above can be performed manually by an operator, but preferably, the inlet on-off valve is opened with the intermediate on-off valve closed to introduce gas into the buffer container, and thereafter Control that controls the operation of each on-off valve and syringe pump so that the syringe pump sucks the gas in the buffer container into the syringe with the inlet on-off valve closed, the intermediate on-off valve open, and the outlet on-off valve closed. Means may be further provided so that a series of operations are automatically performed.

  For such automatic control, it is provided with detection means for outputting a signal corresponding to the volume of the buffer container, and the control means performs operation control of each on-off valve and syringe pump based on the signal of the detection means. Good. As the detection means, a non-contact sensor such as a mechanical switch or an optical sensor can be used.

  According to the gas introduction device of the present invention, it is not necessary to discharge a part of the supplied gas into the atmosphere as in the conventional overflow method, so that the gas is not consumed wastefully. Therefore, the operating cost can be reduced, and environmental pollution caused by releasing an undesired gas to the atmosphere can be prevented. Moreover, since the gas pressure in the syringe can be kept within the pressure-resistant range of the syringe, there is no possibility of the syringe being damaged. Furthermore, because the inside of the pipe can be maintained at a gas pressure higher than atmospheric pressure, it is possible to prevent outside air from entering the pipe from the pipe connection part, etc., and to guarantee the purity of the gas introduced into the analyzer. can do.

  Hereinafter, an embodiment of a gas introduction device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a gas introducing device according to this embodiment.

  In the gas introduction device 1 of the present embodiment, the gas introduction flow path 3 between the pressurized gas supply port 2 and the suction discharge port 9a of the syringe pump 8 has an inlet opening / closing valve 4, a buffer container portion 5, An intermediate on-off valve 7 is provided. On the other hand, an outlet opening / closing valve 14 is disposed in the gas delivery channel 13 between the suction / discharge port 9 a of the syringe pump 8 and the gas delivery port 15. The syringe pump 8 includes a syringe 9 having a suction / discharge port 9a at one end, a plunger 10 that is removably inserted in the syringe 9 and a sensor 11 that detects the position of the plunger 10. Is driven by a plunger drive unit 12 including a drive source such as a motor. The buffer container 5 is a variable volume container to which a constant external pressure higher than the atmospheric pressure is applied, and a sensor 6 is provided for outputting a signal corresponding to the inner volume. The control unit 16 is mainly configured by a CPU, ROM, RAM, etc., receives signals from the sensors 6, 11 and the like, and operates the on-off valves 4, 7, 14 and the plunger drive unit 12 according to a predetermined program. Control. A high pressure gas container 20 is connected to the pressurized gas supply port 2, and an analyzer 21 such as an odor measuring device is connected to the gas delivery port 15.

  FIG. 2 is a view showing an embodiment of the buffer container 5 and the sensor 6 in FIG. In this example, a piston 5b is fitted inside a cylindrical cylinder 5a whose position is fixed, and the internal volume of the cylinder 5a is variable by sliding the piston 5b up and down. A weight 5c having a predetermined weight is fixed to the upper part of the piston 5b, and the piston 5b receives a constant pressure P1 higher than the atmospheric pressure by the weight acting on the weight 5c. The pressure P1 is lower than the gas pressure Pg supplied to the pressurized gas supply port 2, but is naturally higher than the atmospheric pressure. Instead of the weight 5c, pressure may be applied using an elastic force or biasing force such as a spring or rubber. However, since such an elastic force or biasing force changes with time, the weight 5c is preferable in that respect. Is a choice.

  The sensor 6 is turned on when the piston 5b is lowered and the internal volume of the cylinder 5a becomes V1, and the lowest point switch 6a is turned on, and when the piston 5b is raised and the internal volume of the cylinder 5a becomes V2. And an uppermost point switch 6b. As will be described later, the piston 5b can move within a range in which both switches 6a and 6b are turned on. Therefore, the range of change in the internal volume of the cylinder 5a is V1 to V2. Of course, instead of the mechanical switch used here, another sensor such as an optical sensor may be used to detect the position of the piston 5b and the internal volume of the cylinder 5a.

  The gas introduction operation to the analyzer 21 by the gas introduction device of this embodiment will be described. First, as an initial state, it is assumed that the piston 5b in the buffer container portion 5 is at the lowest position as shown in FIG. Further, the plunger 10 of the syringe pump 8 is assumed to be in the most depressed state.

(1) Gas storage in buffer container unit 5 The control unit 16 closes the intermediate on-off valve 7 and opens the inlet on-off valve 4. Since the pressure Pg of the pressurized gas is higher than the external pressure P1 of the buffer container portion 5, the gas in the high-pressure gas container 20 flows into the cylinder 5a from the pressurized gas supply port 2, whereby the piston 5b is gradually pushed up. Then, as shown in FIG. 2A, when the piston 5b rises to the highest position and the uppermost point switch 6b is turned on, the control unit 16 receiving this signal closes the inlet opening / closing valve 4. As a result, no more gas flows in, and an amount of gas corresponding to the internal volume V2 is held in the cylinder 5a. At this time, the gas pressure in the gas introduction flow path 3 between the cylinder 5a and the inlet on / off valve 4 and the intermediate on / off valve 7 is substantially the same as the external pressure P1 of the buffer container section 5.

(2) Gas Suction to Syringe Pump 8 The control unit 16 closes the outlet opening / closing valve 14 and opens the intermediate opening / closing valve 7. Then, the gas introduction flow path 3 between the inlet on / off valve 4 and the suction / discharge port 9a of the syringe pump 8 and the gas delivery flow path 13 between the outlet on / off valve 14 and the suction / discharge port 9a are integrally connected. For this reason, a part of the gas held in the cylinder 5a immediately before that spreads to the flow path. Thereby, the gas pressure is slightly lowered, but the amount of gas held in the cylinder 5a is set according to the internal volume of the flow path so that the gas pressure is slightly higher (for example, about 2%) than the atmospheric pressure. . Although this gas pressure is also applied to the inside of the syringe 9, since it is below the pressure resistance range, there is no risk of breakage or the like.

  Then, the control unit 16 operates the plunger driving unit 12 to pull out the plunger 10 at a predetermined speed. Then, the gas held in the cylinder 5a of the buffer container 5 is sucked into the syringe 9, and the piston 5b is lowered accordingly, and the internal volume of the cylinder 5a is decreased. When the piston 5b is lowered to the lowest position as shown in FIG. 2B, the lowest point switch 6a is turned on. Upon receiving this signal, the control unit 16 stops pulling out the plunger 10 and closes the intermediate on-off valve 7. Thereby, since the increase in the internal volume of the syringe 9 stops, the gas pressure does not drop any more. That is, it is ensured that the gas pressure is kept slightly higher than the atmospheric pressure from before the gas starts to be sucked into the syringe 9 until the suction is stopped. Thereby, it is possible to prevent the outside air from flowing in due to the gas pressure in the pipe lower than the atmospheric pressure.

(3) Gas discharge from the syringe pump 8 The controller 16 opens the outlet on / off valve 14 with the intermediate on / off valve 7 closed. Then, the plunger drive unit 12 is operated to push the plunger 10 at a predetermined speed. Then, the gas held in the syringe 9 is pushed by the plunger 10 and sent from the gas delivery port 15 to the analyzer 21 through the gas delivery channel 13. And if the control part 16 recognizes that the plunger 10 was pushed in to the predetermined position by the detection signal of the sensor 11, it will stop operation | movement of the plunger 10. FIG.

  By the series of operations as described above, the gas supplied in a pressurized state can be reduced to substantially atmospheric pressure and sent to the analyzer 21. During this time, the gas pressure in the flow path (pipe) from the pressurized gas supply port 2 to the gas delivery port 15 is maintained at a state higher than the atmospheric pressure, so that the outside air can be prevented from being mixed with the gas, and pure gas Can be supplied to the analyzer 21.

  In addition, when the internal volume of the syringe 9 of the syringe pump 8 is larger than the internal volume of the cylinder 5a of the buffer container part 5, it is sufficient in the syringe 9 by repeating the operations (1) and (2) a plurality of times. An appropriate amount of gas may be held, and then the operation (3) may be performed to collectively send out the gas held in the syringe 9 by a plurality of suction operations to the analyzer 21.

  Further, the operation control timing of the on-off valves 4, 7, 14 and the plunger driving unit 12 by the control unit 16 can be determined by, for example, time instead of being detected by the on detection of the switches 6 a, 6 b. Specifically, for example, if the pressure of the gas supplied to the pressurized gas supply port 2 is known, in addition to the gas pressure, the gas introduction flow between the pressurized gas supply port 2 and the intermediate on-off valve 7 From the internal volume of the path 3 and the like, the flow rate of the gas flowing into the buffer container 5 can be calculated in the stage (1). If this flow rate is obtained, the time t until the internal volume of the cylinder 5a reaches V2 from V1 can be calculated. Therefore, instead of monitoring whether the uppermost switch 6b is turned on, it may wait for the time t to elapse from the time when the inlet on / off valve 4 is opened, and close the inlet on / off valve 4 at the time t.

  In the stage (2), if the pulling speed of the plunger 10 is constant, the time until the internal volume of the cylinder 5a decreases from V2 to V1 can also be calculated. Thereby, the detection signal of the lowest point switch 6a can be made unnecessary. Moreover, it can replace with the detection signal of the lowest point switch 6a, and the detection signal of the position of the plunger 10 of the syringe pump 8 can also be utilized.

  In addition, the said Example is an example of this invention, Even if it carries out a deformation | transformation, correction, and addition suitably in the range of the meaning of this invention, it is natural that it is included by the claim of this application.

The schematic block diagram of the gas introduction apparatus by one Example of this invention. The figure which shows one Embodiment of the buffer container part and sensor in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas introduction apparatus 2 ... Pressurized gas supply port 3 ... Gas introduction flow path 4 ... Inlet on-off valve 5 ... Buffer container part 5a ... Cylinder 5b ... Piston 5c ... Weight 6 ... Sensor 6a ... Bottom point switch 6b ... Top Point switch 7 ... Intermediate opening / closing valve 8 ... Syringe pump 9 ... Syringe 9a ... Suction / discharge port 10 ... Plunger 11 ... Sensor 12 ... Plunger drive unit 13 ... Gas delivery channel 14 ... Outlet opening / closing valve 15 ... Gas delivery port 16 ... Control unit 20 ... High pressure gas container 21 ... Analytical device

Claims (3)

A gas introduction device for introducing the gas supplied to the pressurized gas supply port into the analyzer,
a) a syringe pump that takes in and discharges gas from the suction and discharge port by reciprocating movement of the plunger;
b) an inlet on / off valve provided in a flow path between the pressurized gas supply port and the suction / discharge port;
an intermediate-off valve provided in a flow path between the c) the entering port opening closed and the suction and discharge port,
d) an outlet on / off valve provided in a flow path between the suction / discharge port and a gas delivery port to the analyzer;
e) a buffer container part connected to a flow path between the inlet on-off valve and the intermediate on-off valve and having a variable volume and being pressurized from the outside in a direction in which the volume decreases;
A gas introducing device comprising:   2. The gas introduction device according to claim 1, wherein the inlet on-off valve is opened with the intermediate on-off valve closed to introduce gas into the buffer container, and then the inlet on-off valve is closed. Control means for controlling the operation of each on-off valve and syringe pump so that the syringe pump sucks the gas in the buffer container portion into the syringe with the intermediate on-off valve opened and the outlet on-off valve closed. A gas introduction device further comprising:   3. The gas introduction device according to claim 2, further comprising detection means for outputting a signal corresponding to the volume of the buffer container portion, wherein the control means is configured to control each on-off valve and syringe pump based on the signal from the detection means. A gas introduction device that performs operation control.

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