Dilution gas mixing unit and exhaust gas analysis system

Patent metadata

Field	Value
Publication number	US-12517019-B2
Application number	US-202117928532-A
Country	US
Kind code	B2
Filing date	Jul 1, 2021
Priority date	Jul 22, 2020
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A dilution gas mixing unit that is used in an exhaust gas analysis system that analyzes the mixed gas obtained by diluting an exhaust gas with the dilution gas, and mixes the dilution gas with the exhaust gas is provided with a dilution gas supply pipe that is connected to an exhaust gas introduction pipe into which the exhaust gas is introduced and supplies the dilution gas to the exhaust gas introduction pipe, a dilution gas sampling unit that is provided in the dilution gas supply pipe and collects the dilution gas, and a backflow prevention member that is provided closer to the exhaust gas introduction pipe than the dilution gas sampling unit in the dilution gas supply pipe and prevents the mixed gas from flowing backward through the dilution gas supply pipe.

First claim

The invention claimed is:

1 . A dilution gas mixing unit used in an exhaust gas analysis system that analyzes a mixed gas obtained by diluting an exhaust gas with a dilution gas, the dilution gas mixing unit mixing the dilution gas with the exhaust gas, the dilution gas mixing unit comprising:
a dilution gas supply pipe connected to an exhaust gas introduction pipe into which the exhaust gas is introduced, the dilution gas supply pipe supplying a dilution gas to the exhaust gas introduction pipe; a dilution gas sampling unit that is provided in the dilution gas supply pipe and collects the dilution gas; and a backflow prevention member provided downstream of the dilution gas sampling unit and upstream of the exhaust gas introduction pipe, in a flow direction of the dilution gas, to prevent the mixed gas from flowing backward in the dilution gas supply pipe, wherein the backflow prevention member includes a through hole through which the dilution gas passes, and is provided along an inner peripheral surface of the dilution gas supply pipe and wherein the dilution gas sampling unit includes an introduction port disposed so as to be positioned in the through hole as viewed from a pipe axis direction in the dilution gas supply pipe, or so as to be positioned inside more than half of an inner diameter from a pipe axis of the dilution gas supply pipe, with the pipe axis being a center.

2 . The dilution gas mixing unit according to claim 1 , wherein the backflow prevention member is an orifice plate.

3 . The dilution gas mixing unit according to claim 1 , wherein the backflow prevention member is a porous orifice plate provided with a number of through holes.

4 . The dilution gas mixing unit according to claim 3 , wherein a plurality of the porous orifice plates is provided along a flow direction of the dilution gas in the dilution gas supply pipe.

5 . The dilution gas mixing unit according to claim 4 , wherein through holes of the porous orifice plates on a downstream side are smaller than through holes of the porous orifice plates on an upstream side.

6 . The dilution gas mixing unit according to claim 1 , wherein the introduction port faces an upstream side of the dilution gas.

7 . The dilution gas mixing unit according to claim 1 , wherein a pressure loss of the dilution gas supply pipe provided with the backflow prevention member is less than 250 Pa.

8 . An exhaust gas analysis system comprising:
a mixed gas flow pipe through which the mixed gas flows; a mixed gas sampling unit that is provided in the mixed gas flow pipe and collects the mixed gas; a constant flow rate mechanism that sets a flow rate of the mixed gas to a constant flow rate; a gas analyzer that analyzes a predetermined component to be measured contained in the collected dilution gas and the collected mixed gas; and a dilution gas mixing unit according to claim 1 .

9 . A dilution gas mixing unit used in an exhaust gas analysis system that analyzes a mixed gas obtained by diluting an exhaust gas with a dilution gas, the dilution gas mixing unit mixing the dilution gas with the exhaust gas, the dilution gas mixing unit comprising:
a dilution gas supply pipe connected to an exhaust gas introduction pipe into which the exhaust gas is introduced, the dilution gas supply pipe supplying a dilution gas to the exhaust gas introduction pipe; a dilution gas sampling unit that is provided in the dilution gas supply pipe and collects the dilution gas; and a backflow prevention member provided downstream of the dilution gas sampling unit and upstream of the exhaust gas introduction pipe, in a flow direction of the dilution gas, to prevent the mixed gas from flowing backward in the dilution gas supply pipe, wherein the backflow prevention member defines a through hole through which the dilution gas passes, and is provided along an inner peripheral surface of the dilution gas supply pipe.

10 . The dilution gas mixing unit of claim 9 , wherein the through hole is non-closable.

Assignees

• Horiba Ltd

Inventors

• Yasuda Masaaki
• Izumi Hiromitsu
• Kimura Takeshi
• Higuchi Masahiro

Classifications

• F01N2270/00

  Mixing air with exhaust gases · CPC title

• F01N2240/20

  a flow director or deflector · CPC title

• G01N1/2252 Primary

  in a vehicle exhaust · CPC title

• G01N2001/2255

  with dilution of the sample · CPC title

• G01M15/102

  by monitoring exhaust gases · CPC title