Colorimetric detector tube

• US 5,004,585 A
• Filed: 09/01/1988
• Issued: 04/02/1991
• Est. Priority Date: 09/01/1987
• Status: Expired due to Fees

• Current Assignee: Dragerwerkk AG Moislinger Allee
• Original Assignee: Dragerwerk AG
• Inventors: Bommer, Rainer
• Primary Examiner(s): Lacey, David L.
• Assistant Examiner(s): Singla, Abanti B.
• Application Number:
  US07/239,318
• Time in Patent Office: 943 Days
• Field of Search: 422/56, 422/59, 422/60, 422/88, 422/58, 436/144, 436/167
• US Class Current: 422/408
• CPC Class Codes: G01N 31/223 for investigating presence of specific gases or aerosols G01N31/221, G01N31/222 take precedence; actuation of fire alarm by presence of smoke or gases G08B17/10
• CPC Class Codes: Y10T 436/22 Hydrogen, per se

Abstract

The invention relates to a colorimetric detector tube having a porous charge. The charge contains an indicating region provided with an indicator ahead of which a pretreatment region is placed which carries a pretreatment substance. The material to be detected form products with the pretreatment substance which lead to a coloration in the indicating region. The detector tube is improved so that its indication is expanded to indicate higher detection concentrations. The detector tube is further improved so that even when the first pretreatment substance is exhausted, a colorimetric indication is made accessible to further quantities of the material to be detected. For this purpose, the charge contained in the tube includes a sequence of several pretreatment regions and indicating regions which alternate one with the other. In another configuration, the charge includes a mixture of pretreatment material and indicating material.

Claims

1. A colorimetric detector tube for detecting hydrogen, the detector tube comprising:

a tubular housing having first and second openable ends which can be opened to allow a stream of a gas to be detected to pass therethrough;

a porous charge disposed in said housing between said ends;

a pretreatment substance arranged on said charge so as to define a plurality of separate pretreatment regions arranged sequentially along the length of said charge so as to be in shaped relationship to each other;

indicator means arranged on saic charge so as to define a plurality of indicating regions alternating with said pretreatment regions;

said pretreatment substance in each of said pretreatments regions being selected to coact with the gas to form a product which reacts with said indicator means to form a stepwise coloration in one or more of said indicating regions depending upon the amount of the gas passing into the tube whereby an overall indication of the detector tube is determined by an addition of the individual linear colorations in the respective indicating regions;

said charge being a granular carrier substrate and said pretreatment substance being impregated into said carrier substrate in said pretreatment regions;

said indicator means being impregnated into said carrier substrate in said indicating regions; and

said pretreatment substance being palladium and said indicator means including Mg (C10₄)₂.

2. The colorimetric detector tube of claim 1, said indicator means also including a ph-indicator.

3. The colorimetric detector tube of claim 1, said indicator means also including crystal violet C₂₅ H₃₀ C1N₃.

4. A colorimetric detector tube for detecting a gas, the detector tube comprising:

a tubular housing having first and second openable ends which can be opened to allow a stream of the gas to be detected to pass through said tube in a direction from said first end to said second end;

a multiplicity of granules defining a charge disposed in said housing between said ends;

a pretreatment substance impregnated into a first plurality of said granules so as to define a plurality of pretreatment centers arranged along the length of said charge;

an indicator substance impregnated into a second plurality of said granules so as to define a plurality of indicating centers along the length of said charge;

said first plurality and said second plurality of granules being thoroughly comingled along the length of said charge; and

said pretreatment substance on each one of said first plurality of granules being selected to coact with said gas to release a product which migrates directly to adjacent ones of said second plurality of granules to react with said indicator substance to form a coloration zone which advances continuously in said direction to a length depending upon the amount of the gas passing into the tube.

5. A colorimetric detector tube for detecting a gas, the detector tube comprising:

a tubular housing having first and second openable ends which can be opened to allow a stream of the gas to be detected to pass through said tube in a direction from said first end to said second end;

a multiplicity of granules defining a charge disposed in said housing between said ends;

a pretreatment substance impregnated into said granules so as to define a plurality of pretreatment centers disposed in each of said granules and arranged along the length of said charge;

an indicator substance also impregnated into each of said granules so as to define a plurality of indicating centers along the length of said charge; and

said pretreatment substance on each one of said granules being selected to coact with said gas to release a product which reacts with said indicator substance on said one granule so that the granules collectively define a coloration zone which advances in said direction in dependence upon the amount of the gas passing into the tube.