JPS59226848A - Apparatus for measuring exhaust gas of automobile - Google Patents

Abstract

PURPOSE:To prevent an adsorption loss of an exhaust gas and to improve a precision and stability of measurement of said gas by dipping a sampling line at a downstream side from a pipe for introducing a sample and all of the parts in an oil vessel, and circulating an oil to the outer circumferences of a sample probe and the pipe for introducing the sample to perform the temp. control. CONSTITUTION:The sampling line 4 at the downstream side from the pipe 3 for introducing the sample of an automobile exhaust gas, and all of the sampling parts 5-12 are dipped in the oil vessel 13, and the oil is circulated to the outer circumferences of the sample probe 2 and the pipe 3 by a pump 14 in the vessel 13 to perform the temp. control. Consequently the adsorption loss in the line of the exhaust gas is prevented, and the measuring precision and the stability are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automobile exhaust gas measuring device, and in particular to temperature control of its sampling line.

<Prior Art> When sampling and measuring automobile exhaust gas, it is necessary to control the temperature of the sampling line so that the exhaust gas is not adsorbed or lost in the sampling line. Conventional temperature control methods include electric immersion, heating at oil temperature, and a combination of both. However, with either method, it is difficult to maintain a constant temperature distribution inside the heating tank or oil tank, and because there are connections such as joints installed outside the heating tank, the temperature decreases in these parts, causing the temperature inside the exhaust gas to drop. It has the disadvantage of causing adsorption and loss of T-HC (total hydrocarbons), etc.

<Objective and Structure of the Invention> Therefore, the present invention immerses the entire sampling line except the sample probe and the sample introduction tube in an oil tank, and uses a pump in the oil tank to pump oil into the sample glove and the sample introduction pipe. By circulating the oil around the outer periphery, the temperature of all the sampling lines is controlled by the oil temperature, and at the same time, the oil in the oil tank is stirred through the oil circulation by the pump, and the temperature of each part is uniformly controlled. This eliminates the shortcomings of .

<Example> An example of the present invention will be described below based on the drawings. 1st
The figure shows a device for measuring the total hydrocarbon concentration contained in automobile exhaust gas. In the figure, 1 is a dilution tunnel that dilutes automobile exhaust gas with the atmosphere and introduces it, and 2 is a device that protrudes into the tunnel. 3 is a sample introduction tube connected to the globe, and 4 is a sampling line extending from the introduction tube 3 to the detector 5. This line 4 includes a sample shutoff valve 6, a primary filter 7, a sampling pump 8, a needle pulp 9, a secondary filter 10, a protective filter 11, capillaries 12, 12, and a detector 5.
are provided in that order. As the detector 5, for example, a flame ionization detector (FID) is used.

In this measuring device, the sampling line 4 on the downstream side of the sample introduction pipe 3 and all the sampling parts 5 to 12 provided therein are immersed in the oil tank 13, and A pump 14 in an oil tank 13 circulates oil around the outer periphery of the sample probe 2 and the sample introduction tube 3 located in the sample probe 2 .

In the figure, 15 is an oil circulation path. Further, the detector 5, the protective filter 11, and the capillaries 12, 12 are housed in a stainless steel block 16 and immersed in an oil tank 13. An oil circulation path 15 from the pump 14 is also piped into this block 16. Note that the sampling parts directly immersed in the oil tank 13 are appropriately oil-sealed to prevent oil from entering the inside of the pump, for example. Further, as the sample shutoff valve 6, an air switching valve is used because if a solenoid valve is used, there is a risk that oil will be burned due to the arc generated during switching.

Air can be supplied to the shutoff valve 6 by a sampling operation unit 17 provided outside the oil tank. This unit 17 is composed of a solenoid valve unit 17a, a pressure reducing valve with filter 17b, and a ball pulp 17C. Incidentally, the oil in the oil tank 13 is heated to a predetermined temperature by a heating means such as a heater (not shown).

As shown in FIG. 2, the oil circulation path of the sample probe 2 and sample introduction tube 3 includes an oil inflow path 19 and an oil outflow path around a flow path 18 through which diluent gas flows in both the sample probe and the sample introduction tube. The channel 20 is formed concentrically, and the inflow channel and the outflow channel are communicated with each other by connecting the sample probe 2 and the sample introduction tube 3.
And the inlet channel 19 and the outlet channel 20 at the tip of the sample probe.
It is constructed by communicating with and,
The oil inflow path 19 is pipe-connected to the circulation path 15 of the pump through a connection flange portion 21 located at the starting end side of the sampling line 4, while the oil outflow path 20 is connected to the flange portion 21 at the starting end side of the sampling line 4.
1 to communicate with the inside of the oil tank 13.

In the figure, 22... is an oil seal. Also, in Figure 1,
23 Solenoid valve unit for switching zero gas, span gas, and bag gas and introducing them into the sampling line,
Sae is an air valve, 25 is a unit that supplies air and fuel to the detector 5, and is composed of a pressure regulator 2 (i), a solenoid valve 27, etc. 28 is an activated carbon filter, and 29 is a pump. 30 is a pressure regulating unit for flowing a sample at a predetermined flow rate to the detector 5, and is composed of a pressure gauge 31, a pressure regulator 32, and a flow meter 33.
35, 36, and 37 are flanges for connection.

<Effects of the Invention> As explained above, the automobile exhaust gas measuring device according to the present invention circulates oil around the outer periphery of the sample probe and the sample introduction pipe using a pump in the oil tank, and also circulates oil around the outer circumference of the sample probe and the sample introduction pipe, and also circulates oil around the outer circumference of the sample probe and the sample introduction pipe. The sampling line and all the sampling parts installed on the way are immersed in the oil tank, and the temperature of the sampling line and all the sampling parts is controlled with oil, so it has the following effects. . In other words, since the pump circulates the oil in the oil tank, the oil temperature in the oil tank becomes uniform, and this uniform oil temperature controls the temperature of all sampling lines and sampling parts. Gas is no longer adsorbed or lost within the line, and the measurement accuracy and stability of the device can be greatly improved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is an overall piping configuration diagram, and Fig. 2 is a sectional view of a sample probe and a sample introduction tube. 2...Sample probe, 3...Sample introduction tube,
4... Sampling line, 13... Oil tank, 1
4...Bong 0 22 19 20 Fig. 2 2

Claims (1)

[Claims] A pump in the oil tank circulates oil around the outer periphery of the sample probe and the sample introduction tube, and the sampling line downstream of the sample introduction tube and all sampling parts installed along the way are placed in the oil tank. An automobile exhaust gas measuring device characterized in that the sampling line and all the sampling parts are heated and temperature controlled in oil by immersion.