JPS625657Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a ventilated, internally pressurized, explosion-proof thermostatic chamber for an analyzer, for example, which houses and operates an analyzer such as a gas chromatograph, and is particularly intended to be compact.

Analyzers such as gas chromatographs are permanently installed in factory equipment and used as in-process monitoring devices. In such cases, to ensure the accuracy of the analyzer, store the analyzer in a constant temperature bath.
It is common to operate analyzers at a constant temperature. For this reason, a heater is provided in the constant temperature bath, and the heater maintains the inside of the constant temperature bath at a constant temperature.

By the way, the analyzer is installed close to the process. Therefore, the surrounding area is often a dangerous place where explosive gas and the like are present. On the other hand, since a heater is provided inside the thermostatic oven and consumes a large amount of electric power, it is necessary to prevent explosive gas from entering the thermostatic oven. Ventilated internal pressure explosion-proof thermostatic chambers were designed to be used in such cases, and supply air to the thermostatic chamber and exhaust it from the exhaust port to keep the pressure inside the thermostatic chamber constant compared to the outside pressure. The temperature is set higher than the above value to prevent outside air from entering the thermostatic chamber. In reality, the air supplied to the thermostatic chamber is heated by a heater, and the heated air is circulated within the chamber to equalize the temperature distribution within the chamber. Therefore, the temperature of the air exhausted from the exhaust port of the thermostatic chamber is relatively high, and in most cases exceeds the temperature limit set by explosion-proof standards.

For this reason, conventionally, a cooling means is provided at the exhaust port of the constant temperature oven, and the temperature of the exhausted air is lowered by the cooling means and then released to the outside air.

FIG. 1 shows a conventional thermostat. In the figure, 1 indicates a constant temperature bath. Air having a constant pressure is supplied to the thermostatic chamber 1 from a supply port 2 through a pressure reducing valve 3 . Constant temperature bath 1
A heater 4 is provided inside the tank, and the supplied air is heated by the heater 4, blown out from the air outlets 5 and 6, circulated within the tank, and exhausted from the exhaust port 7.
A cooling means 8 is provided at the exhaust port 7, and the cooling means 8
Exhaust is carried out through the

The cooling means 8 generally has a structure in which heat is radiated by heat radiating fins. However, in the cooling means 8 having this structure, the temperature of the heat radiation fin itself must not exceed the limit temperature. Therefore, the heat dissipation area is increased to lower the temperature of the heat dissipation fins. For this reason, the shape of the cooling means 8 becomes large and takes up a lot of space, so a large space must be provided for the installation of the thermostatic chamber, resulting in the inconvenience of being restricted in the installation of the analyzer. Furthermore, since the heat dissipation fins are made of a material with high thermal conductivity, they also have the disadvantage of being expensive.

The purpose of this invention is to provide a ventilated internal pressure explosion-proof structure constant temperature bath for an analyzer which eliminates the need for cooling means 8 and allows the analyzer to be installed even in a small area.

FIG. 2 shows an embodiment of a constant temperature bath according to this invention. Parts in the figure that correspond to those in Figure 1 are given the same reference numerals and their repeated explanation will be omitted, but in this invention, the air supplied to the heater 4 installed in the thermostatic chamber 1 is branched before the heater. The branched air is mixed with the air exhausted from the exhaust port 7, and this mixing lowers the exhaust temperature to below the limit temperature.

In FIG. 2, reference numeral 9 indicates an air branching means, which branches part of the air supplied to the thermostatic chamber 1 and sends the branched air to the regulating valve 10.
is supplied to the mixing means 11 through. Mixing means 11
In the step, the air exhausted from the thermostatic chamber 1 and the air branched by the branching means 9 are mixed, the exhaust temperature is lowered, and the air is exhausted. Reference numeral 12 indicates a thermometer, which monitors the temperature of the mixed air exhausted from the mixing means 11, adjusts the regulating valve 10 as necessary to adjust the amount of branched air, and exhausts the air. Ensure that the temperature is below a predetermined value.

Therefore, according to this invention, the temperature of the exhaust gas can be lowered below the limit temperature specified by the explosion-proof standards without providing a cooling means, and the overall shape of the thermostatic chamber 1 can be made smaller, thereby eliminating restrictions on the installation of the analyzer. can be made that much looser. Furthermore, cost reduction can be expected since there is no need to use cooling means.

The mixing means 11 is constructed, for example, as shown in FIG. In FIG. 3, 13 indicates the inside of the thermostatic oven 1, and 14 indicates the outside of the thermostatic oven 1. A valve 15 is attached to the exhaust port 7 of the thermostatic chamber 1. This valve 15 is always biased by a spring 16 so as to close the exhaust port 7. An air passage 17 is formed opposite the center of one valve 15, and air branched by branching means 9 is supplied to this air passage 17.

With this configuration, by supplying branched air to the air passage 17, the air pressure causes the valve 15 to move against the biasing force of the spring 16 to open the exhaust port 7. Therefore, the air in the thermostatic chamber 1 is also exhausted to the outside through the exhaust port 7. At this time, the air discharged from the thermostatic chamber 1 and the branched air are mixed, the temperature is lowered, and the air is exhausted. However, by providing the valve 15 as in this example, even if the air supply is stopped due to some accident, the valve 15
Since the spring 16 closes the exhaust port 7,
It is safe because outside air does not enter into the thermostatic chamber 1.

As explained above, according to this invention, the cooling means can be omitted by simply changing the structure, and thereby the shape of the thermostatic chamber 1 can be made smaller, and the restrictions on the installation location of the analyzer can be relaxed. In addition, cost reduction can be expected, and the effect will be significant in practical use.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view for explaining a conventional ventilated internal pressure explosion-proof structure constant temperature bath for analyzers, Fig. 2 is a cross-sectional view showing one embodiment of this invention, and Fig. 3 is a cross-sectional view showing an embodiment of this invention. It is a sectional view showing an example of a mixing means. 1: Constant temperature chamber, 2: Air supply port, 4: Heater,
7: Exhaust port, 9: Branching means, 11: Mixing means.

Claims (1)

[Scope of Claim for Utility Model Registration] Air is sent into a thermostatic oven, the air is heated by a heater in the thermostatic oven, the temperature inside the thermostatic oven is maintained constant, and the air is exhausted from an exhaust port, and the temperature inside the thermostatic oven is controlled by outside pressure. In a ventilated internal pressure explosion-proof thermostatic chamber for an analyzer designed to increase the pressure of the thermostatic chamber, there is provided a means for branching the air supplied into the thermostatic chamber before entering the thermostatic chamber; A valve is provided in common with the exhaust port, and a biasing force is applied to the valve to close the valve. biasing means selected to cause the valve to be in a closed state if no air is supplied; and a biasing means selected to cause the valve to be in a closed state if the valve is not supplied with air; A ventilated internal pressure explosion-proof thermostatic chamber for an analyzer, which is equipped with a means for discharging water to the outside.