US 4,063,821 A · Gas detector tube reader

Abstract

The reader apparatus includes a clamp colocated with a photoelectric cell and lamp. A scale, e.g. calibrated in millimeters extends laterally from the photoelectric cell/lamp axis. A gas detector tube whose column of test particles is stained from one stain-starting end to a region part way therealong is clamped in the reader with its starting end of stain juxtaposed with the scale. The tube is manually moved axially until a portion of the lightest-in-color region is directly between the photoelectric cell and lamp. The transmitted light indicator is adjusted to align with one extreme on its scale. Then the tube is manually moved axially until a portion of the darkest-in-color region is directly between the photoelectric cell and lamp. The transmitted light indicator is adjusted to align with the other extreme on its scale. Finally the tube is slid axially until the indicator coincides with a preselected intermediate tick-mark, e.g. indicating a light transmittance value half-way between the two extremes. With the tube clamped at that location, the length of stain is read from the scale, by noting the site of juxtaposition of the starting end of stain on the scale. Accordingly, the more pronounced reading is made by the human and the measure that is harder for a human to make consistently is uniformly made by the device. A particular clamp construction is disclosed, wherein fiber optics lead light from the lamp through one clamp jaw directly to the gas detector tube and from a diametrically opposed site on the tube through the other clamp jaw to the photoelectric cell.

Claims13

Dependent claims

For reading the length of stain from a gas detector tube which tube includes a transparent, elongated tubular sidewall having an inlet end and an outlet end and having a filling of indicator-bearing, gas porous material which is specific to a looked-for constituent in the sense that said material turns color progressively along the tube when exposed to a gas including the constituent as a sample of the gas is drawn through the tube, so that a distinct end of stain is first produced at the end of said filling of indicator-bearing, gas porous material nearest the inlet end of the tube and until the constituent is exhausted a stain front progresses along said filling of the tube toward the outlet end of the tube, a gas detector tube reader, comprising:

a housing having:
a. means for releasably clamping an individual gas detector tube and for permitting the tube while clamped to be moved longitudinally;
b. an illuminated lamp and means for directing illumination thereof in a beam transversally upon an axial section of the tube while clamped;
c. a photoelectric cell aligned with said beam transversally opposite the location of said illuminated axial section, and means for substantially confining the access of light to the photoelectric cell to such light of said beam as is transmitted generally transversally through the tube;
d. a meter electrically connected to the photoelectric cell and constructed to provide an output proportional to the light reaching the photoelectric cell;
e. first mark means on the housing coincident from the standpoint of an observer before the reader with the longitudinal axis of said beam;
f. second mark means on the meter, intermediate the two extremes of meter output characteristic of most stained and least stained sections of the tube being read,
whereby the length of stain of the gas detector tube being read may be measured as the distance along the tube length from said first mark means to the distinct end of stain, when the tube has been slid longitudinally until the meter output coincides with said second mark means.

5 more elements

For reading the length of stain from a gas detector tube which tube includes a transparent, elongated tubular sidewall having an inlet end and an outlet end and having a filling of indicator-bearing, gas porous material which is specific to a looked-for constituent in the sense that said material turns color progressively along the tube when exposed to a gas including the constituent, as a sample of the gas is drawn through the tube, so that a distinct end of stain is first produced at the end of said filling of indicator-bearing, gas porous material nearest the inlet end of the tube and until the constituent is exhausted a stain front progresses along said filling of the tube toward the outlet end of the tube,

a method which comprises:
a. moving the tube along its own longitudinal axis with axially successive segments of the tube filling in the transversally crossing path of a lamp-to-photoelectric cell beam of light while noting both the maximum and the minimum output of the photoelectric cell, as indication of the light transmittance through unstained and fully stained portions of the tube filling;
b. maintaining the position of the tube relative to the beam when the photoelectric cell provides a preselected intermediate value of output, as an indication of the point along the length of the tube to which the stain front has progressed;
then
c. measuring the distance along said tube between the intersection of the beam and tube at said position and the distinct end of stain as an indication of the length of stain.

2 more elements

Dependencies are inferred from the claim text.

Gas detector tube reader

Life of this patent

Gas detector tube reader

Life of this patent

Abstract

Claims13