Method for detection of foreign matter contents in gases

• US 5,047,723 A
• Filed: 12/01/1988
• Issued: 09/10/1991
• Est. Priority Date: 06/03/1986
• Status: Expired due to Term

• Current Assignee: Environics Oy (CNIM Group SA)
• Original Assignee: Pertti Puumalainen
• Inventors: Puumalainen, Pertti
• Primary Examiner(s): Wieder, Kenneth
• Assistant Examiner(s): Mueller, Robert W.
• Application Number:
  US07/286,063
• Time in Patent Office: 1,013 Days
• Field of Search: 324/464, 324/469, 324/459, 324/71.3, 324/468, 324/470, 324/466, 324/465, 324/452, 250/385.1, 250/379, 340/629, 73/28.02, 73/23.2
• US Class Current: 324/464
• CPC Class Codes: G01N 27/622 Ion mobility spectrometry
• CPC Class Codes: G01N 27/66 and measuring current or voltage

Abstract

A method for detection of alien matter content in gas, in which the gas and the materials contained in it are ionized in an ionization room (1). The present methods are inaccurate and unreliable. The invention is based on a method, in which the ionized gas is led through chambers (2) containing different electric fields, out of which at least from one of the chambers the field current is measured, from which a signal is obtained, which describes the existence of alien matters in the gas. More parameters are obtained for detection of different materials by measuring favorably the currents passed through several electric field chambers as well as possibly by branching off from the ionization source the flow to different analysis lines of the electric field chambers.

Claims

1. A method for detecting foreign matter in gases, comprising the steps of:

ionizing the gas containing foreign matter in an ionization zone,

passing the ionized gas containing foreign matter through a plurality of chambers, each with different electric fields,

measuring field currents passing transversely through two or more of said chambers, and

obtaining corresponding signals, wherein amounts and relationships of said signals provide an analysis of the foreign matter in the gases.

2. A method according to claim 1, wherein said step of passing the ionized gas containing foreign matter through chambers comprises passing the gas through sequentially arranged electric field chambers.

3. A method according to claim 1, wherein said step of passing the ionized gas containing foreign matter comprises passing the gas through at least two adjacent channels, each of said channels containing at least one of said electric field chambers, the field current passing through at least one chamber of each channel being measured and a signal based on each field current measurement being obtained.

4. A method according to claim 1, wherein said step of passing the ionized gas containing foreign matter comprises passing the gas along a tortuous path within each of said chambers, said tortuous path being defined by current measuring plates extending inwardly from walls of the chamber, with a gap between each measuring plate and chamber wall defining at least two electric field sub-chambers within said chamber, an intensity of an electric field in each said sub-chamber being different from one another.