JP3634037B2 - Piping structure with reduced particulate adhesion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piping structure in an apparatus for measuring particulates contained in exhaust gas from a diesel engine or the like.
[0002]
[Prior art]
In the particulate measurement device, diluted exhaust gas obtained by mixing diluted air with exhaust gas from the engine and diluting to a predetermined ratio in the main pipe is introduced into the analyzer.
[0003]
Its main pipe, for example, as shown in FIG. 3, typically, insulation material b widely used in air conditioning or the like is wound on the outside, the outer cylinder c was the Serare outside of the heat insulating material b It has a double pipe structure, and a double pipe f for introducing exhaust gas d and dilution air e is connected to the upstream end opening of the main pipe a.
[0004]
[Problems to be solved by the invention]
However, since the exhaust gas exhausted from the engine is high temperature, the temperature is lowered by introducing diluted air from the outside. However, although the temperature is high and the heat insulating material b is applied, the inner surface of the main pipe a Since the temperature is lower than that of the diluted exhaust gas, dew condensation occurs on the inner surface, so that particulates to be collected by the filter may adhere to the inner surface of the main pipe a.
[0005]
This invention is made in view of such a situation, and it aims at providing the piping structure which aimed at the adhesion reduction of particulates.
[0006]
[Means for Solving the Problems]
In the present invention, means for solving the above-described problems are configured as follows.
That is, in the invention described in claim 1, together with the inner surface of the main pipe for circulating by mixing dilution air into the exhaust gas is mirror-finished, the main pipe by interposing a vacuum layer in the outer tube to be Sera The outer surface of the outer cylinder is mirror-finished.
[0007]
In the second aspect of the invention, the inner surface of the inner pipe of the exhaust gas introduction pipe connected so as to face the upstream end opening of the main pipe in the first aspect of the invention is mirror-finished. , the outer tube by interposing a vacuum layer in the inner pipe is canceller to be the outer surface of the outer tube is characterized by comprising a mirror finish.
According to a third aspect of the present invention, an exhaust gas introduction pipe having a double pipe structure comprising an inner pipe for introducing exhaust gas and an outer pipe covering the inner pipe mixes diluted air with the exhaust gas. And connected to the upstream end opening of the main pipe to be circulated, a vacuum layer is formed between the inner pipe and the outer pipe, and further, the dilution air is formed outside the outer pipe. Provided is a piping structure for reducing the adhesion of particulates, characterized in that a flow path is provided for circulating the particles.
[0008]
With such a configuration, according to the first aspect of the present invention, first, the inner surface of the main pipe is finished to be a mirror surface, so that the particulates are less likely to adhere to the main pipe and the outer cylinder. Since the vacuum layer is interposed between the outer pipe and the outer surface of the outer cylinder is finished to be a mirror surface, the propagation of heat between the inside and the outside of the main pipe is prevented, so condensation in the main pipe Etc. is prevented, precipitation of particulates is prevented, and measurement accuracy is improved.
[0009]
More specifically, the heat generated in the main pipe is prevented from being transferred to the outside by the vacuum layer, while the external heat is prevented from being transferred into the main pipe, and the radiant heat is reflected by the mirror surface in the main pipe. Therefore, the release of heat to the outside is prevented, and the radiant heat from the outside is reflected and blocked by the mirror surface of the outer cylinder, so that the difference between the temperature of the inner surface of the main pipe and the temperature of the diluted exhaust gas is less likely to occur.
[0010]
In the second aspect of the invention, the inner surface of the inner tube through which exhaust gas directly flows and the outer surface of the outer tube are mirror-finished, and a vacuum layer is interposed between the inner tube and the outer tube. As a result, the difference between the temperature of the inner surface of the inner tube and the temperature of the diluted exhaust gas is less likely to occur, and the deposition of particulates can be further prevented.
Furthermore, in the invention according to claim 3, the inner tube and the outer tube of an exhaust gas introducing tube having a double-pipe structure comprising an inner tube for introducing exhaust gas and an outer tube covering the inner tube. Since a vacuum layer is formed between the inner pipe and the exhaust gas temperature in the inner pipe, the difference between the temperature of the inner pipe and the exhaust gas in the inner pipe can be reduced, and even before the exhaust gas is introduced into the main pipe, particulates into the inner pipe are reduced. Precipitation adhesion can be prevented.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a piping structure for reducing particulate adhesion according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a configuration diagram of a main pipe, and FIG. 2 is a partially enlarged view thereof. In these drawings, reference numeral 1 is a main pipe, its inner surface 11 is mirror-finished, and 2 is a vacuum layer 3 interposed therebetween. an outer tube which is the Serra outside the main pipe 1, the outer surface 21 is mirror-finished. 22 is a vacuum quote socket.
[0012]
4 is a mounting flange connected to the upstream opening end of the main pipe 1 via a connecting member 5, 6 is a positioning flange fixed to the downstream side of the main pipe 1, and 7 is connected to the main pipe 1 via an O-ring 8. The fitted mounting flanges 9 are fixed to both ends of the outer cylinder 2 and are fixed to the mounting flange 7 by fastening bolts and nuts (not shown) through the O-ring 10.
[0013]
13 is allowed to face the tube end into the main pipe 1 of the upstream end in the opening exhaust gas inlet tube, an inner tube 14 for introducing the exhaust gas and the Serra through the vacuum layer 15 in the inner tube 14 thereof It has a double tube structure with the outer tube 16 . In addition, a flow path for allowing diluted air to flow between the outer tube 17 and the outer tube 16 provided outside the outer tube 16 is formed . Further, the inner surface 141 of the inner tube 14 and the outer surface 161 of the outer tube 16 are mirror finished.
[0014]
18 is a socket for evacuating between the inner tube 14 and the outer tube 16, 19 is a socket for introducing dilution air, 20 is a positioning flange fixed to the outer cylinder 17, and 23 is through an O-ring 24. Te in the canceller the mounting flange to the outer cylinder 17 is fixed through the O-ring 10 to the mounting flange 12 fixed to the outer tube 2 by fastening bolts and nuts (not shown).
[0015]
25 is a mounting flange to be the canceller the outer cylinder 17 through the O-ring 26, by engaging the bolts and nuts (not shown), a mounting flange 4 which is fixed to the main pipe 1 is fixed through an O-ring 27 ing.
[0016]
With the above-described configuration, the exhaust gas (100 to 500 ° C.) is directly introduced into the inner pipe 14 of the exhaust gas introduction pipe 13 and the dilution gas (25 ° C. ± 5 ° C.) introduced from the socket 19 and the main pipe 1 is mixed in the opening on the upstream side, and becomes a diluted exhaust gas of about 52 ° C. at the maximum, and is sent downstream.
[0017]
There is a sudden drop in temperature around the upstream open end of the main pipe 1 where the exhaust gas is directly mixed with the dilution air, but the particulates adhere due to the mirror finish of the inner surface 11 of the main pipe 1. In addition to the difficulty, the amount of heat in the main pipe 1 is conducted to the outside by the vacuum layer 3 set to a relatively large volume between the outer cylinder 2 and the mirror finish of the inner surface 11. While being effectively prevented and the outer surface 21 of the outer cylinder 2 is mirror-finished, it is possible to prevent external heat from being propagated into the main pipe 1, and the temperature of the inner surface 11 of the main pipe 1. And the temperature difference between the diluted exhaust gas is less likely to occur, and the precipitation of particulates is effectively prevented.
[0018]
On the other hand, even in the exhaust gas introduction pipe 13 connected to the previous stage of the main pipe 1, the inner surface 141 of the inner pipe 14 through which exhaust gas directly flows and the outer surface 161 of the outer pipe 16 are mirror-finished, and By interposing the vacuum layer 15 between the inner pipe 14 and the outer pipe 16, the difference between the temperature of the inner surface 141 of the inner pipe 14 and the exhaust gas temperature is less likely to occur, and before being introduced into the main pipe 1. Even in the stage, particulate deposition can be prevented.
[0019]
As described above, the temperature difference between the exhaust gas and the exhaust gas from the exhaust gas introduction pipe 13 through the main pipe 1 to the downstream heat pipe (not shown) is reduced . Since the inner surface 141 of the tube 14, the outer surface 161 of the outer tube 16, the inner surface 11 of the main pipe 1, and the outer surface 21 of the outer cylinder 2 are mirror-finished, particulate adhesion is prevented and measurement accuracy is improved. Can do it.
[0020]
【The invention's effect】
As described above, according to the first aspect of the present invention, the inner surface of the main pipe is mirror finished, the outer pipe is covered with a vacuum layer interposed in the main pipe, and the outer face of the outer pipe is mirror-finished. Since it is finished, particulates are less likely to adhere to the inner surface, and heat transfer between the inside and outside of the main pipe is suppressed, reducing the difference between the pipe inner surface temperature and the exhaust gas temperature. By doing so, precipitation of particulates is prevented, and high measurement accuracy is obtained.
[0021]
In the invention described in claim 2, the inner surface of the inner pipe of the exhaust gas introduction pipe connected so as to face the upstream end opening of the main pipe is further mirror-finished, and the inner pipe is vacuum-finished. by interposing a layer causes the outer tube, since the mirror-finished outer surface of the outer tube, the difference between the temperature of the pipe inner surface of the direct exhaust gases can be reduced, the more particulate Adhesion can be prevented.
[0022]
Furthermore, in the invention according to claim 3, the inner tube and the outer tube of an exhaust gas introducing tube having a double-pipe structure comprising an inner tube for introducing exhaust gas and an outer tube covering the inner tube. Since a vacuum layer is formed between the inner pipe and the exhaust gas temperature in the inner pipe, the difference between the temperature of the inner pipe and the exhaust gas in the inner pipe can be reduced, and even before the exhaust gas is introduced into the main pipe, particulates into the inner pipe are reduced. Precipitation adhesion can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a piping structure for reducing particulate adhesion according to the present invention.
FIG. 2 is an enlarged cross-sectional view of the main part.
FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a conventional piping structure.
[Explanation of symbols]
1 ... main pipe, 11,141 ... inner surface, 2 ... outer cylinder, 21,161 ... outer surface, 3,15 ... vacuum layer, 13 ... exhaust gas introduction pipe, 14 ... exhaust gas introduction pipe inner pipe, 16 ... exhaust gas Outer pipe of introduction pipe .

Claims (3)

With the inner surface of the main pipe for circulating by mixing dilution air into the exhaust gas is mirror-finished, the main pipe by interposing a vacuum layer is canceller outer cylinder under the outer surface of the outer cylinder is mirror-finished A piping structure designed to reduce the adhesion of particulates. With the inner surface of the inner tube of the exhaust gas inlet pipe connected so as to face the downstream end to the upstream end opening of the main pipe is mirror finished, the outer tube is canceller object by interposing a vacuum layer in said tube pipe structure an outer surface of the outer tube is attempted to adhere reduction of particulate according to 請 Motomeko 1 ing is mirror-finished. The upstream end of the main pipe for the exhaust gas introduction pipe having a double pipe structure comprising an inner pipe for introducing the exhaust gas and an outer pipe covering the inner pipe to mix and distribute the diluted air to the exhaust gas Connected so that the downstream end faces the opening, a vacuum layer is formed between the inner tube and the outer tube, and a flow path for circulating the dilution air is provided outside the outer tube. A piping structure designed to reduce particulate adhesion.

Images