JPH0122131Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sampling valve used for taking out a fixed amount of sample gas in, for example, a process gas chromatograph.

For example, as shown in FIG. 1, a probe 12 is inserted into a tube 11 through which process gas is flowing, and the process gas introduced through the probe 12 is filtered through a separator 13 to remove large contaminants, and then filtered through a filter 14 to remove small contaminants. After removing the substances, the sample gas flows through the sample gas introduction pipe 20 to the sampling valve 15. The process gas passes through the sampling valve 15 as shown by the solid line and is delivered to the exhaust pipe 17 through the metering pipe 26. When sampling a sample gas, the sampling valve 15 is switched, the carrier gas from the carrier gas supply pipe 18 passes through the sampling valve 15 as shown by the dotted line, and a certain amount of process gas in the metering pipe 16 is transferred to the sample take-out pipe 1.
9 and sent to an analyzer (not shown).

Tar, coke, etc. contained in the process gas may enter the sampling valve 15 and accumulate within the sampling valve 15, adversely affecting the analysis operation. For example, such a fear occurred when analyzing outlet gas from a naphtha cracking furnace. In order to prevent the analysis gas introduction pipe and the sampling valve from being blocked or damaged, a filter 14 installed at the inlet of the sampling valve 15 is used to completely remove tar, coke, etc.
If the mesh of the filter is made fine, the filter will quickly become clogged, making it impossible to collect sample gas. When the mesh of the filter 14 is made rough, fine dust reaches the sampling valve 15, and the dust accumulates and adheres within the sliding surface of the sampling valve 15. In this state, the sampling valve 15
If sliding switching is performed, the sliding surface will be scratched, causing leaks, reducing the functionality of the sampling valve, and making normal sampling impossible. Particularly in the case of remote sampling, in which sampling is performed near the process and the sampling gas is sent to an analysis unit located at a remote location, tar, coke, etc. can reach the sampling valve immediately without clumping up on the sampling valve 15. The above problem was likely to occur. Note that the sampling valve 15 and the like may be housed in the thermostatic chamber 21.

The purpose of this invention is to provide a sampling valve that is free from damage even if a sample gas containing dust is supplied, allows normal sampling to be performed over a long period of time, and causes less clogging of the filter.

According to this invention, when the connection port of the metering tube and the connection port of the sample take-out tube are not connected, the passage communicating with the connection port of the sample gas introduction tube is almost linear with the through hole of the distributor. The sample gas containing dust is allowed to pass through this through hole. Furthermore, it is possible to stop the gas flow through the through hole, that is, to stop the gas flow and return to the normal gas flow condition in the sampling valve, and then transfer the sample gas in the metering tube to the sample removal tube as a carrier gas. Send it with . In this manner, when no sampling is performed, the sample gas is discharged through the through hole, and there is little possibility that dust in the sample gas will enter the sliding portion of the sampling valve.

2 and 3 show a conventional sampling valve, in which a rotating shaft 23 is located at the center of a disc-shaped collector 22.
are inserted and fixed, and pipe-shaped connection ports 24a to 24h are pushed in and fixed on one side at equal angular intervals around the rotating shaft 23, and the inner ends of each connection port 24a to 24h communicate in the extending direction to form a passage. 25 are formed reaching the other surface of the collector 22, respectively. A distributor 26 is disposed so as to be rotatable in contact with a surface of the collector 22 opposite to the connection ports 24a to 24h. Day distributor 26
A center hole 27 is passed through the center hole 27, and a rotating shaft 23 is inserted through the center hole 27, and the distributor 26 can rotate around this shaft 23. On the surface of the distributor 26 facing the collector 22,
Four arcuate groove connecting passages 28a to 28d are formed at equal angular intervals, each having an angular length of approximately 45 degrees, and facing the position of the passage 25 on the surface of the collector 22. ing.

The distributor 26 can be rotated by 45 degrees, and in one angular position, the connecting ports 24a, 24b are connected to each other through the connecting passage 28a, and the connecting ports 24c24d, 24e24f, 2
4g24h are connection passages 28b, 28c,
They are interconnected through 28d. Connection port 24a,
24b, 24c, 24d, 24e, and 24f are connected to, for example, the sample gas inlet pipe 20, one end of the metering tube 16, the sample takeout tube 19, the carrier gas supply tube 18, the other end of the metering tube 16, and the discharge tube 17, respectively, in FIG. They should be connected to each other. Therefore, for example, gas from the sample gas introduction tube passes through the connection passage 28a from the connection port 24a, and is supplied to the measuring tube from the connection port 24b. From this state, the distributor 26
When rotated by 45 degrees, the connection ports 24b24c, 24d24e, 24f24g,
24h24a are connecting passages 28a, 28, respectively.
b, 28c, and 28d, and are in a condition to send the sample in the measuring tube 16 to the analyzer.

For example, the switching state in Fig. 4A is 10 minutes, and the switching state in Fig. 4B is
There is a large time difference, such as 30 seconds, between the switching states, and when gas containing a lot of dust flows in the state shown in FIG. 4A, the connecting passages 28a and 28c
Dust adheres to and adheres to the surface of the collector 22, and if a switching operation is performed in this state, the adhered dust will scratch and damage the sliding surface of the distributor 26.

An example of the sampling valve of this invention is shown in FIGS. 5 and 6, in which parts corresponding to those in FIGS. 2 and 3 are given the same reference numerals. In this invention, the connection port 24a of the gas introduction pipe and the connection port 24b of the metering pipe are
A through hole 29 is formed in the distributor 26 to extend in the direction of extension of the passage 25 communicating with the connection port 24a of the gas introduction pipe and to be connected thereto. In this example, the connecting passage 28
a, and passes through the distributor 26 parallel to the shaft 23, and in the switched state shown in FIG. do.

It is possible to stop the gas passing through this through hole 29. In this embodiment, the opening/closing plate 31 is brought into contact with the surface of the distributor 26 opposite to the collector 22, and the opening/closing plate 31 has a through hole 32.
are formed, and by rotating the opening/closing plate 31 around the shaft 23, the through holes 29,
32 are aligned in a straight line, or the through holes 29 and 32 are completely separated from each other and the through hole 29 is closed by the opening/closing plate 31 as shown in FIG. 5B. One end of an exhaust pipe 33 is connected to the through hole 32 as necessary. The rotation of the opening/closing plate 31 may be controlled in the same manner as the rotation of the distributor 26.

In the embodiment of this invention described above, the state shown in FIG. 5A is always maintained. Connection port 24
a. Since the passage 25 and the through holes 29 and 32 are on a straight line, most of the gas from the gas introduction pipe 20 flows through the connection port 24a, the passage 25, and the through holes 29 and 32, and especially dust flows through this passage. There is no risk of dust adhering to the sliding parts between the collector 22 and the distributor 26. To collect a sample, the opening/closing plate 31 is closed as shown in FIG. 5B,
As a result, the gas from the connection port 24a of the inlet pipe passes through the metering tube 16 in the state shown in FIG. The switching state shown in FIG. B may be achieved. In the previous embodiment, in the state shown in FIG. 5A, part of the gas also flows to the metering tube 16 side, so that a line purge effect can be obtained.

In addition to rotating the opening/closing plate 31 to perform opening/closing control, the discharge pipe 33 may be provided with a lamp serving as a valve to control the flow of gas in the pipe 33 on and off. The gas flow in the through hole 29 may be opened and closed by a shutter without using the opening/closing plate 31.

As described above, according to this invention, the sample gas is transferred to the connecting passage 28 in the sampling valve.
The time flowing along the longitudinal direction from a to 28d is
It can be reduced to about 1/2 to 1/6 of the conventional one, and there is no risk of dust accumulating in the sampling valve, resulting in a longer life. Furthermore, since the dust can pass through the sampling valve, the mesh of the filter used before the sampling valve can be made somewhat rougher, and the life of the filter can be extended accordingly.

[Brief explanation of the drawing]

Figure 1 is a connection diagram showing the sampling device, Figure 2
The figure is a sectional view showing a conventional sampling valve, Figure 3 is an exploded perspective view of Figure 2, Figure 4 is a diagram showing the switching state of the conventional sampling valve, and Figure 5 is an example of the sampling valve according to this invention. The sectional view shown in FIG. 6 is an exploded perspective view of FIG. 5. 22: Collector, 23: Axis, 24a to 24h:
Connection port, 25: Passage, 26: Distributor, 28a to 28d: Connection passage, 29, 32: Through hole, 31: Opening/closing plate.

Claims (1)

[Scope of utility model registration request] One side is provided with connection ports to which a sample gas inlet pipe, a metering pipe, a discharge pipe, a carrier gas supply pipe, and a sample takeout pipe are to be connected, and each connection port is connected to a passageway reaching the other surface, and a collector, and the collector. a distributor which can be rotated against the other surface of the collector, has a connection passage formed on the surface facing the collector, and switches connection ports to be connected to each other through the connection passage by rotation. In the sampling valve provided with a user, at a rotational position of the collector and the distributor where the connection port of the sample gas introduction pipe and the connection port of the measuring tube are connected, the connection port of the sample gas introduction pipe is connected to the connection port of the sample gas introduction pipe. a through hole formed in the distributor along the extending direction of the passage connected to the passage, and a stop that stops the gas flow through the through hole when sample gas is introduced into the metering tube. A sampling valve characterized by being provided with means.