JPH0725691Y2 - Gas chromatograph - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a gas chromatograph for preventing out-of-gas of carrier gas, for example.

(Prior Art) A gas chromatograph generally includes an injector, a column thermostat, and a detector, which usually have a heater for adjusting the column temperature, and feed a carrier gas into the column piped to these, and By injecting a sample into these and moving them, and detecting the components of the sample in the process of movement, it is possible to analyze the components of the sample.

(Problems to be solved by the invention) In such an analysis, the column is generally placed in a high temperature state, and a thermal equilibrium state is maintained by the carrier gas moving inside, so that, for example, the carrier gas is out of gas. If so, not only the analysis becomes impossible, but also the column becomes a kind of empty state by the heater, and the stationary phase liquid and the adsorption phase are deteriorated or destroyed, and there is a problem that it becomes unusable.

Such a situation is caused not only by the carrier gas, but also by the exhaustion of the air or hydrogen gas supplied to the FID detector, etc., and especially when the automatic analysis using the auto sampler is performed, the instrument is empty. There was a problem that it was virtually impossible to analyze after analysis.

The present invention solves such a problem, avoids interruption of analysis due to shortage of gas supplied to the gas chromatograph, secures reliability and safety of analysis when switching gas by a spare gas cylinder, and further It is an object to provide a gas chromatograph designed for rationalization.

(Means for Solving the Problems) Therefore, the gas chromatograph of the present invention is provided with a pressure sensor in the passage of the supply gas, and when a predetermined pressure is detected by the sensor,
While enabling the solenoid valve inserted in the passage,
In a gas chromatograph capable of opening a heat generating circuit inside the gas chromatograph, an auxiliary gas conduit communicating with a spare gas cylinder is connected to a supply gas passage upstream of the pressure sensor, and a solenoid valve is inserted in the gas conduit. At the same time, at the time of gas switching by the spare gas cylinder, the heating circuit can be opened only when the gas pressure in the passage recovers a predetermined pressure to avoid interruption of analysis due to gas shortage, and at the time of gas switching by the spare gas cylinder. It is characterized by ensuring the reliability and safety of the analysis of, and being able to rationalize spare gas piping.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.
In the figure, reference numerals 1 and 2 denote a gas cylinder installed outside the gas chromatograph 3 and its spare gas cylinder, and the same carrier gas is filled inside.

The gas cylinder 1 communicates with a gas conduit 5 that is provided inside the gas chromatograph 3 via a valve 4,
An auxiliary gas conduit 6 is connected to the base end of the pipe 5. The auxiliary gas conduit 6 is communicated with the spare gas cylinder 2 via a valve 7, and an electromagnetic valve 8 is inserted at an appropriate position of the pipe 6, so that the gas in the cylinder 2 is gasified by a control signal described later. It can be supplied to the conduit 5.

The gas conduit 5 in the gas chromatograph 3 can be connected to a diversion pipe 9 communicating with a detector described later, and a pressure regulator 10 and a pressure sensor 11 capable of outputting a detection signal are provided upstream of the connection position. Further, a mass flow controller 12 and a pressure sensor 13 as a pressure gauge are inserted on the downstream side.

Further downstream of the gas conduit 5, an injector 14 equipped with a heating unit for injecting a sample into a carrier gas, a separation column 16 piped in a column thermostatic bath 15, and a detector 17 equipped with a detector thermostatic bath Are inserted, and these electric heating circuits can be opened by a control signal to be described later when the pressure of the carrier gas decreases.

That is, the pressure sensor 11 detects a predetermined pressure of the carrier gas, for example, the lowest gas pressure that can be analyzed by the gas chromatograph 3, and inputs the detection signal to the control unit 18. Above control unit
18 has a built-in microcomputer, which can output a control signal to the control circuit 19 on condition of the input signal from the sensor 11.

Based on the control signal, the control circuit 19 outputs a drive signal, which is a control signal, to the solenoid valve 8 and the alarm device 20 to open the solenoid valve 8 and enable the alarm device 20.

Then, after the electromagnetic valve 8 is opened, if the sensor 11 confirms the recovery of the abnormal gas pressure pressure within a predetermined time defined by a timer, for example, a signal is input from the sensor 11 to the control unit 18. Then, the control signal input from the unit 18 to the control circuit 19 is canceled, the open state of the solenoid valve 8 is maintained, and the operation of the alarm device 20 is stopped.

On the other hand, when the pressure sensor 11 does not detect the pressure increase in the gas conduit 5, the signal input from the sensor 11 to the control unit 18 and the control signal input from the unit 18 to the control circuit 19 are held, and the solenoid valve 8 is held. Valve open status and alarm
Control unit while maintaining operation of 20
A control circuit 19 outputs an operation stop signal to the injector 14, and each electric heating circuit of the column thermostatic chamber 15 and the detector 17 via 18 to stop the heating operation of these.

In addition, reference numeral 22 in the figure denotes an integrator or the like that can be linked to the detector 17.

FIG. 2 shows another embodiment of the present invention, and the same reference numerals are used for the components corresponding to those of the above-mentioned embodiment. That is, this embodiment shows a case where the detector 17 is applied to the gas chromatograph 3 equipped with an FID detector, which uses hydrogen gas and air in addition to the carrier gas, and other than the cylinder 1 filled with the carrier gas. A hydrogen gas cylinder 23 filled with hydrogen gas and an air pressure source 24 such as an air compressor are installed outside.

Then, these gas supply sources 1, 23, 24 are connected to the detector 17. Solenoid valves 27, 28, 29 and pressure sensors 30, 31 on each conduit 5, 25, 26
Is inserted, and each minimum gas pressure that can be analyzed is detected by each of these sensors 11, 30, 31 and the signal is input to the control unit 18.

The control unit 18 operates on condition that the signal from any one of the sensors 11, 30 and 31 is input, sends a control signal to the control circuit 19, and the circuit 19 sends an alarm 20 and each electromagnetic signal. A control signal is output to the valves 27, 28, 29, and each electric heating circuit of the injector 14, the column thermostat 15, and the detector 17.

That is, the alarm device 20 is activated to notify the situation, and the solenoid valves 27, 28, 29 are closed to stop the supply of each gas to prevent the empty release of the gas, and in particular, to empty the hydrogen gas. While preventing accidents due to discharge, each of the electric heating circuits is turned off to prevent deterioration of the column 16 due to so-called empty heating and to protect it.

In the figure, 32 and 33 are pressure regulators, and 34 and 35 are valves.

(Operation) In the gas chromatograph configured as described above, the gas supply pressure by the spare gas cylinder 2 is detected by the pressure sensor 11 inserted in the gas conduit 5, and the sensor 11 is detected from both the gas cylinder 1 and the spare gas cylinder 2. Since it is used for detecting the gas supply pressure, the saving of the sensor 11 and the auxiliary gas conduit 6
The piping cost can be reduced by streamlining the piping.

Next, the operation of the gas chromatograph will be described with reference to the first embodiment shown in the figure. During analysis, the valves 4 and 7 of the gas cylinder 1 and the spare gas cylinder 2 are opened, and the control unit 18 and the control circuit 19 are turned on. To be done. In this case, the solenoid valve 8 is normally closed and the supply of carrier gas to the gas conduit 5 is stopped.

Therefore, initially, the carrier gas is supplied to the gas chromatograph 3 exclusively by the gas cylinder 1.
When the gas pressure in the gas conduit 5 is normal above the minimum pressure, the pressure sensor 11 for detecting the pressure does not operate, and the analysis by the gas chromatograph 3 is normally performed.

When, for example, the cylinder 1 runs out of gas during such analysis, the pressure of the carrier gas in the gas conduit 5 decreases, and the pressure decreases to the lowest pressure that can be analyzed by the gas chromatograph 3. Is detected by the pressure sensor 11, and the signal is input to the control unit 18.

The control unit 18 outputs a control signal to the control circuit 19 on condition of the signal input from the sensor 11, and outputs a drive signal which is a control signal from the circuit 19 to the solenoid valve 8 and the alarm device 20, respectively.

As a result, the solenoid valve 8 is opened, the carrier gas in the spare cylinder 2 is supplied to the gas conduit 5, and the alarm 20
Turns on and sounds a warning sound or blinks an alarm lamp to warn of the pressure drop condition. Therefore, the surrounding workers are informed of the above state by the warning.

Thus, the carrier gas in the cylinder 2 is supplied to the gas conduit 5, and the gas pressure in the pipe 5 quickly recovers to the normal pressure equal to or higher than the minimum pressure, whereby the detection by the pressure sensor 11 is canceled.

Therefore, the signal input to the control unit 18
The control signal input from the unit 18 to the control circuit 19 is canceled, the operation of the alarm device 20 is stopped, and the solenoid valve 8
The valve open state of is maintained.

Therefore, the surrounding workers recognize that the gas pressure of the carrier gas has recovered to the normal pressure because the operation of the alarm device 20 has stopped, and the carrier gas is continuously supplied to the gas conduit 5 via the solenoid valve 8. By doing so, the analysis by the gas chromatograph 3 is continued. Therefore, reliability and safety of analysis at the time of gas switching by the spare gas cylinder 2 are secured.

In this case, the switching from the gas cylinder 1 to the spare cylinder 2 is performed promptly by the solenoid valve 8 and the normal pressure is quickly recovered, so that the analysis is interrupted at the time of the switching or the analysis accuracy at that time is lowered. There is nothing to do.

On the other hand, in spite of the gas supply from the spare cylinder 2, if the gas conduit 5 does not recover the predetermined pressure within a certain time after the detection of the gas pressure drop due to, for example, a piping trouble of the auxiliary gas conduit 6, the pressure sensor 11 controls The signal input to the unit 18 and the control signal input from the unit 18 to the control circuit 19 are held, and the open state of the solenoid valve 8 and the operating state of the alarm device 20 are maintained.

Therefore, the surrounding workers are informed of the abnormal situation of the carrier gas supply system and are urged to take immediate measures.

Further, in the case of the above abnormality, the control circuit 19 through the control circuit 19 to the injector 14 and the column thermostat
An operation stop signal is output to each of the heating circuits of 15 and the detector 17 to stop the heating operation thereof.

As a result, the analysis of the gas chromatograph 3 is practically stopped, and a sterile empty analysis can be avoided, and by stopping the heating of the injector 14 and the heating chamber of the column thermostat 15 and the detector 17, Columned 16
The so-called empty heating is prevented, the deterioration of the column 16 is prevented, and the column 16 is protected.

In addition, in this series of control processes, for example, when the spare gas cylinder 2 is not prepared, the respective heat generating circuits are immediately turned off due to the decrease in the gas pressure of the gas conduit 5, and the alarm device 20 warns of this state.

Further, in each of the above embodiments, the control unit 18 and the control circuit 19 are built in the gas chromatograph 3,
All or part of these may be installed outside the chromatograph 3 and centrally controlled to process the signals from a single or a plurality of gas chromatographs.

As described above, according to the present invention, the alarm 20 is used to warn of the decrease in the gas pressure of the supply gas such as the carrier gas, so that the workers in the surroundings can take the prescribed measures immediately, and the gas chromatograph 3 is used. Minimize analysis interruptions.

(Effect of the Invention) As described above, in the gas chromatograph of the present invention, the auxiliary gas conduit communicating with the spare gas cylinder is connected to the supply gas passage upstream of the pressure sensor, and the solenoid valve is inserted in the gas conduit. When the gas runs out, the gas supply can be switched to the spare gas cylinder, and the interruption of the analysis due to the gas run out can be avoided.

Further, when the gas is switched by the spare gas cylinder, the heating circuit can be closed only when the gas pressure in the passage recovers a predetermined pressure, so that the reliability and safety of the analysis at the time of gas switching by the spare gas cylinder can be improved. Can be secured.

Furthermore, the gas supply pressure by the spare gas cylinder is detected by the pressure sensor inserted in the passage of the supply gas, and the installation of the pressure sensor in the auxiliary gas conduit is omitted, so that the sensor can be saved and the auxiliary gas conduit can be rationalized. The piping cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG. 2 is an explanatory view showing another embodiment of the present invention. 3 ... Gas chromatograph, 11 ... Pressure sensor 14 ... Injector, 15 ... Column thermostat 16 ... Separation column, 17 ... Detector 20 ... Alarm device

Claims (1)

[Scope of utility model registration request] 1. A gas chromatograph in which a pressure sensor is provided in a supply gas passage, and when a predetermined pressure is detected by the sensor, an electromagnetic valve inserted in the passage can be operated and a heat generating circuit inside a gas chromatograph can be opened. In the graph, a supply gas passage upstream of the pressure sensor is connected to an auxiliary gas conduit communicating with a spare gas cylinder, and a solenoid valve is inserted in the gas conduit. A gas chromatograph characterized in that the heating circuit can be closed only when the gas pressure recovers a predetermined pressure.