JPH0738962U - Gas chromatograph column thermostat - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a thermostat for columns in which the analysis cycle is shortened by lowering the temperature of the thermostat once heated to a higher temperature. A thermostat for a column of a gas chromatograph, which has a heating means 3 inside or outside the thermostat 1 and sends air to the thermostat directly or via the external heating means to raise the temperature in the thermostat. In the tank, the first pressure reducing valve 5 is set so that the air has a predetermined flow rate in advance.
A second pressure reducing valve 15 which is set so that a flow rate larger than that of the first pressure reducing valve flows, and a switching valve 12 for switching the air delivered from the first and second pressure reducing valves, When the temperature of the constant temperature bath is raised by the switching valve,
Air is sent from the pressure reducing valve, and when the temperature of the constant temperature bath is lowered, the air is sent from the second pressure reducing valve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thermostat for a gas chromatograph column, and more particularly to a thermostat with an improved temperature lowering rate of the thermostat.

[0002]

[Prior art]

 In gas analyzers such as process gas chromatographs, an air bath type thermostatic chamber is used to house the separation column. 2 and 3 are structural explanatory views showing a conventional constant temperature bath for such a gas analyzer. In the figure, 1 is a constant temperature bath in which a separation column and the like are housed, 2 is a separation column placed in the constant temperature bath, 3 is a heater, 4 is a pipeline, 5 is a pressure reducing valve with a constant flow rate, 6 2 is an outlet, FIG. 2 shows an example in which the heater is arranged outside the constant temperature tank, and FIG. 3 shows an example in which the heater is arranged inside the constant temperature tank.

In the conventional example having such a structure, the air whose constant flow rate is set by the pressure reducing valve 5 is delivered to the constant temperature bath 1 through the heater 3 or directly. The inside of the constant temperature bath 1 is agitated by a fan or the like (not shown) to maintain the constant temperature inside the constant temperature bath 1. After that, the air is discharged from the discharge port 6. A temperature sensor (not shown) is arranged in the constant temperature bath 1, and the heater is turned on / off to control the temperature to a predetermined temperature.

By the way, in the sample to be measured sent to the column 2, the elution time of each component varies depending on the kind of the adsorbent (not shown) packed in the column 2 and the temperature in the constant temperature bath 1. However, for example, there is a problem that the measurement cycle becomes long in order to accurately separate all the petroleum components at a constant temperature. Therefore, for samples containing those with a relatively slow elution rate, a method of shortening the measurement cycle is employed by gradually increasing the temperature in the constant temperature bath 1 from about 50 ° C to about 300 ° C. In that case, the measurement of the first sample is completed, and when measuring the next sample, it is necessary to lower the elevated temperature of the constant temperature bath to the initial set temperature (for example, about 50 ° C). .

[0005]

[Problems to be solved by the device]

 However, even when the heater power is turned off, the conventional configuration described above has a problem that it takes a long time to lower the temperature in the thermostatic chamber because the set flow rate of the pressure reducing valve is constant. Note that it is possible to increase the set flow rate of the pressure reducing valve in advance in order to shorten the cooling time, but in that case there is a problem that the power of the heater must be increased and power consumption will increase. The present invention was made in order to solve the above-mentioned problems of the prior art. A constant temperature bath for a column was designed to shorten the analysis cycle by lowering the temperature of the constant temperature bath once heated to a higher temperature. The purpose is to provide.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention has a heating means inside or outside the constant temperature bath, and sends air into the constant temperature bath directly or via the external heating means to raise the temperature inside the constant temperature bath. In a thermostat for a gas chromatograph column, the first pressure reducing valve is set so that the air flows at a predetermined flow rate, and the second pressure reducing valve is set to flow at a flow rate higher than that of the first pressure reducing valve. Valve and a switching valve for switching the air delivered from the first and second pressure reducing valves. The switching valve delivers 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, it is characterized in that the air is sent from the second pressure reducing valve.

[0007]

[Action]

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

[0008]

【Example】

 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 designated by the same reference numerals, and duplicate description will be omitted. Reference numeral 20 denotes an outer casing in which the constant temperature bath 1, the sampling valve 8, the detector 9 and the like are arranged. Reference numeral 5 is a first pressure reducing valve which is set to flow a predetermined flow rate in advance, and 15 is a second pressure reducing valve which is set to flow more flow rate than the first pressure reducing valve. Are switched by the switching valve 12 and sent to the constant temperature bath 1. Reference numeral 10 is a temperature sensor for measuring the temperature inside the constant temperature tank, and although not shown in the figure, a fan for stirring air is provided inside the constant temperature tank. Reference numeral 16 is a throttle valve that discharges the air in the tank through the discharge port 6.

In the above-mentioned configuration, the switching valve 12 sends out the air of the flow rate set by the first pressure reducing valve 5 into the constant temperature tank 1, and the inside of the constant temperature tank is, for example, 50 ° C. to 300 ° C. according to a predetermined sequence. It is heated by the heater 3 stepwise to some extent. Then, the heater is turned off before the measurement of the first measurement sample is completed and before the next sample is introduced into the column 3, the switching valve 12 is set so that a larger flow rate than that of the first pressure reducing valve flows. 2 Switch so as to send out air from the pressure reducing valve 15.

As a result, the temperature inside the constant temperature bath is rapidly lowered to reach the initial temperature. After that, the switching valve 12 switches again to send out the air of the first pressure reducing valve. The present inventors set the temperature of the constant temperature chamber at 8 liters, the flow rate from the first pressure reducing valve at 50 liters per minute, and the flow rate from the second pressure reducing valve at 100 liters per minute. According to the experiment of raising the temperature to 50 ° C. and lowering the temperature to 50 ° C. again, it was possible to lower the temperature in 30 minutes, which took 60 minutes when the temperature was lowered with the flow rate of the first pressure reducing valve.

Note that the analysis may be started at an initial temperature of room temperature or lower, and in such a case, a commercially available vortex tube (when air is introduced from the inlet, cool air is fed to the outlet between the switching valve 12 and the constant temperature bath 1). Is obtained and the degree of cooling becomes stronger as the air flow rate increases. In that case, the cooling efficiency increases according to the configuration of the present invention.

[0012]

[Effect of device]

 According to the present invention, as described in detail with reference to the above embodiments, the first pressure reducing valve is set so that the air delivered to the constant temperature chamber has a predetermined flow rate, and It is equipped with a second pressure reducing valve that is set to flow a large amount of flow and a switching valve that switches the air sent from the first and second pressure reducing valves, and the switching valve raises the temperature of the constant temperature bath. The heater capacity (power consumption) is increased because the air is sent from the first pressure reducing valve when the heating is performed, and the air is output from the second pressure reducing valve when the temperature of the constant temperature bath is lowered. The temperature decrease rate can be increased without the need for this, and as a result, the analysis cycle of the gas chromatograph can be shortened.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of a constant temperature bath for columns 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]

 1 Constant Temperature Tank 2 Column 3 Heater 4 Pipeline 5 First Switching Valve 6 Discharge Port 12 Switching Valve 15 Second Pressure Reduction Valve

Claims (1)

[Scope of utility model registration request] 1. A thermostat for a gas chromatograph column having a heating means inside or outside the thermostat, and feeding air into the thermostat directly or via the external heating means to thermostat the inside of the thermostat. In the above, the air is a first pressure reducing valve which is set to flow at a predetermined flow rate,
A second pressure reducing valve which is set so that a flow rate larger than that of the first pressure reducing valve flows; and a switching valve which switches the air delivered from the first and second pressure reducing valves. The gas chromatograph is characterized in that air is sent from the first pressure reducing valve when the temperature of the constant temperature chamber is kept constant, and air is sent from the second pressure reducing valve when the temperature of the constant temperature chamber is lowered. Column constant temperature bath.