JP2591991Y2 - Thermostat for column of gas chromatograph - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermostat for a column of a gas chromatograph, and more particularly to a thermostat having an improved temperature decreasing rate of the thermostat.

[0002]

2. Description of the Related Art In a gas analyzer such as a process gas chromatograph, an air bath type thermostat is used to accommodate a separation column and the like. FIGS. 2 and 3 are explanatory views showing the configuration of a conventional thermostat for such a gas analyzer. In the figure, reference numeral 1 denotes a thermostat in which a separation column and the like are accommodated,
2 is a separation column arranged in a thermostat, 3 is a heater, 4
Is a pipeline, 5 is a pressure reducing valve with a constant flow rate, and 6 is a discharge port. FIG. 2 shows an example in which a heater is arranged outside a thermostat, and FIG. 3 shows a heater in a thermostat. An example is shown.

In a conventional example having such a configuration,
The air set at a constant flow rate by the pressure reducing valve 5 is sent out into the thermostat 1 via the heater 3 or directly. Further, the inside of the thermostat 1 is stirred by a fan or the like (not shown) to maintain the inside of the thermostat 1 at a constant temperature. After that, the air is discharged from the discharge port 6. A temperature sensor (not shown) is arranged in the thermostat 1, and controls the temperature to a predetermined temperature by, for example, turning on and off a heater.

Meanwhile, the elution time of each component of the sample to be measured sent to the column 2 varies depending on the type of the adsorbent (not shown) filled in the column 2 and the temperature in the thermostat 1. However, for example, in order to accurately separate all the components of petroleum at a constant temperature, there is a problem that a measurement cycle becomes long. Therefore, for a sample including a sample having a relatively slow elution rate, a method of shortening the measurement cycle by stepwise constant temperature in the constant temperature bath 1 from, for example, about 50 ° C. to about 300 ° C. is adopted. In that case, the measurement of the sample taken first is completed, and when the next sample is measured, it is necessary to lower the raised temperature of the constant temperature bath to the initial set temperature (for example, about 50 ° C.).

[0005]

However, even when the power of the heater is turned off, the conventional configuration described above has a problem that it takes a long time to lower the temperature in the constant temperature bath because the set flow rate of the pressure reducing valve is constant. there were. In order to shorten the cooling time, it is conceivable to increase the set flow rate of the pressure reducing valve in advance. However, in that case, it is necessary to increase the power of the heater, and there is a problem that power consumption increases. The present invention has been made to solve the above-mentioned problems of the prior art. The temperature of a thermostat once heated to a high temperature is rapidly lowered to thereby shorten the analysis cycle, thereby enabling a column thermostat to be shortened. The purpose is to provide.

[0006]

In order to solve the above-mentioned problems, the present invention has a heating means inside or outside a constant temperature bath, and sends air to the constant temperature bath directly or through the external heating unit. In the thermostat for column of the gas chromatograph which raises the temperature inside the thermostat, the air flows through a first pressure reducing valve which is set in advance so as to flow at a predetermined flow rate, and a larger flow rate than the first pressure reducing valve flows. And a switching valve for switching the air sent from the first and second pressure reducing valves. The switching valve is used to increase the temperature of the thermostatic bath by the first pressure reducing valve. The method is characterized in that air is sent from a pressure reducing valve, and when the temperature of the constant temperature bath is lowered, switching is performed so as to send out air from the second pressure reducing valve.

[0007]

When the temperature of the thermostatic bath is lowered, the switching valve switches so as to send out air from the second pressure reducing valve which is set so that a larger flow rate flows than the first pressure reducing valve. As a result, the cooling rate is increased.

[0008]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention. In the figure, the same elements as those in FIG. 2 are denoted by the same reference numerals, and duplicate description will be omitted. Reference numeral 20 denotes an outer casing, in which the thermostat 1, the sampling valve 8, the detector 9, and the like are arranged. 5 is a first set in advance so that a predetermined flow rate flows.
The pressure reducing valves 15 are second pressure reducing valves set so that a larger flow rate flows than the first pressure reducing valve. The air passing through these pressure reducing valves is switched by the switching valve 12 and sent out to the constant temperature bath 1. . Reference numeral 10 denotes a temperature sensor for measuring the temperature in the thermostat, and although not shown, a fan for stirring air is provided in the thermostat. Reference numeral 16 denotes a throttle valve which discharges the air in the tank through the discharge port 6.

In the above configuration, the switching valve 12 sends out the air at a flow rate set by the first pressure reducing valve 5 into the constant temperature bath 1, and the inside of the constant temperature bath is, for example, about 50 ° C. to 300 ° C. according to a predetermined sequence. Heated by the heater 3 step by step. Then, the measurement of the first measurement sample is completed,
Before the next sample is introduced into the column 3, the heater is turned off and the switching valve 12 sends out air from the second pressure reducing valve 15 set to flow at a larger flow rate than the first pressure reducing valve. Switch.

As a result, the temperature in the constant temperature bath is rapidly lowered to reach the initial temperature. Thereafter, the switching valve 12 switches again so as to send out the air of the first pressure reducing valve. Note that the present inventors set the volume of the thermostatic chamber to 8 liters and the flow rate from the first pressure reducing valve to 50 liters per minute.
1, the flow rate from the second pressure reducing valve is set to 100 l / min, the temperature in the thermostat is raised from 50 ° C. to 320 ° C., and the temperature is again raised to 50 ° C.
According to the experiment in which the temperature was lowered until the temperature was reduced at the flow rate of the first pressure reducing valve, it took 60 minutes, but the temperature could be lowered in 30 minutes.

Incidentally, the analysis may be started when the initial temperature is lower than the normal temperature. In such a case, a commercially available vortex tube (cool air is supplied to the outlet when air is supplied from the inlet) between the switching valve 12 and the thermostatic bath 1. Is obtained, the degree of cooling increases as the air flow rate increases), but in this case, according to the configuration of the present invention, the cooling efficiency increases.

[0012]

According to the present invention, as described in detail with the above embodiments, the first pressure reducing valve, which is set in advance so that the air to be sent into the constant temperature bath flows at a predetermined flow rate, and the first pressure reducing valve,
Second set to flow more than the pressure reducing valve
A pressure reducing valve; and a switching valve for switching air sent from the first and second pressure reducing valves. The switching valve sends out the air from the first pressure reducing valve when raising the temperature of the constant temperature bath. However, when the temperature of the constant temperature bath is lowered, the temperature is switched so as to send out the air from the second pressure reducing valve, so that the cooling rate can be increased without increasing the heater capacity (power consumption). The analysis cycle of the gas chromatograph can be shortened.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of a column thermostat of the present invention.

FIG. 2 is a configuration diagram showing a conventional example.

FIG. 3 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Constant-temperature bath 2 Column 3 Heater 4 Pipe line 5 1st switching valve 6 Discharge port 12 Switching valve 15 2nd pressure reducing valve

Claims (1)

(57) [Scope of request for utility model registration] 1. A gas chromatograph column thermostat which has a heating means inside or outside a thermostat, and sends air to the thermostat directly or through the external heating means to thermostat the thermostat. In the above, the air is provided with a first pressure reducing valve set in advance so as to flow at a predetermined flow rate,
A second pressure reducing valve set to flow at a larger flow rate than the first pressure reducing valve; and a switching valve for switching air sent from the first and second pressure reducing valves, wherein the switching valve is The gas chromatograph is characterized in that when the temperature of the thermostatic bath is made constant, air from the first pressure reducing valve is sent out, and when the temperature of the thermostatic bath is lowered, switching is performed so as to send out air from the second pressure reducing valve. Thermostat for column.