GB2048468A

GB2048468A - Gas pollution sampling

Info

Publication number: GB2048468A
Application number: GB7915428A
Authority: GB
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC
Priority date: 1979-05-03
Filing date: 1979-05-03
Publication date: 1980-12-10
Also published as: GB2048468B

Abstract

A portable gas sampler apparatus for air pollution measurement comprises a head mounted sample probe tube 15 curved such that in use end 16 is adjacent the wearer's nose and mouth, sample probe tube 15 being coupled at its other end via a flexible tube to a gas absorber cell 18 supported in a pocket 31 on a plastics bib 32 secured to the upper chest of the wearer. The sample tube may also include a dust filter. <IMAGE>

Description

SPECIFICATION Gas pollution sampling This invention relates to environmental pollution measurement, and in particular to a portable apparatus for detecting and measuring pollutants.

Control and measurement of environmental pollution involve various techniques and sampling procedures dependant on the nature and concentration of the pollutant involved. Where the pollution is related to the specific exposure of personnel to noxious gases, vapours, or dust particles, it is generally necessary to provide a portable sampling apparatus for monitoring the pollutant. A number of systems have been devised for this purpose.

Some of these have an adjustable harness arrangement for filament to the person exposed, whilst others are simply affixed to the clothing.

These previously described arrangements suffer from a number of disadvantages. In particular, such arrangements are often unsatisfactory where a concentration gradient of a pollutant exists. Thus, a truly representative sample of the pollutant can be obtained only from the breathing zone of the person exposed to the pollutant, i.e. any sampling device must be adjacent the nose and mouth of that person.

Taking a breathing zone sample is usually achieved by attaching a sample device on the shoulder of the person exposed to the pollutant, and in some cases extending a probe close to the nose and mouth. One serious disadvantage of such an arrangement is that, due to movements of the head of the person, the probe is not in a constant position in relation to the nose and mouth. In cases of high concentration gradients of pollutants, results may be obtained which are at considerable variance with the actual exposure experienced by the person to whom the apparatus is fitted.

The object of the invention is to minimise or to overcome these disadvantages.

According to the invention there is provided a portable gas sampler apparatus, including a sample tube mounted on a head band and through which air or gas may be drawn, the tube, when the apparatus is in use, being disposed adjacent the nose and mouth of a wearer, and a gas absorber cell coupled to the sampler tube via a flexible tube.

According to the invention there is further provided agas sampler apparatus as claimed in claim 1, and which further includes a flexible bib having a pocket for receiving the gas absorber cell and provided with means whereby the bib may be affixed to the upper chest of the wearer.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure f is a plan view of the head-set sample probe unit of the gas sampling arrangement.

Figure 2 is a cross-sectional view of the gas absorber cell of the sampling arrangement.

Figure 3 shows a bib whereby the absorber cell of Fig. 2 may be mounted on the upper portion of the body.

Referring to Fig. 1, the head-set sampling device forming the sensor portion of the arrangement includes a lightweight headband 11 to one side of which a plastics pad 1 2 is fitted to steady the headband 11 on the head of the wearer. To the other side of the headband is fitted a metal or plastics disc 1 3 provided with a foamed pad 14 and on which a stainless steel tube 1 5 is mounted. The tube 1 5 is curved to follow the contours of the wearer's face such that the end 1 6 of the tube is adjacent the nose and mouth. In some applications the end 1 6 of the tube 1 5 may be fitted with a filter capsule 1 7 e.g. for taking dust samples.In use, air is drawn with the end 1 6 of the tube 1 5 and through the tube via a flexible tube (not shown) to the gas absorber cell 1 8 (Fig. 2).

The absorbtion cell 1 8 of Fig. 2 is of the fritted glass type and includes a glass container through the upper wall of which an inlet tube 21 is sealed the inner end of the tube 21 is flared to form a cone 22 which is covered by a porous glass frit 23. An outlet tube 24 provides a means of drawing a gas or air through the cell. In use the cell 1 8 is approximately quarter filled with a suitable liquid reagent for the pollutant gas to be absorbed. Advantageously the wall of the cell 1 8 may be indented below the outlet tube 23 to form a splash guard 25 to prevent loss of the reagent in the form of spray. In use a suction tube (not shown) is attached to the tube 24 to draw air or gas through the apparatus.

Referring now to Fig. 3, the cell 1 8 is supported in a pocket 31 on a bib 32 formed from a flexible plastics material such as polyethylene or plasticised polyvinyl chloride (PVC).

The bib 32 is secured to the upper chest by two tapes 33 passing from the lower corners of the bib beneath the arms of the wearer, crossed at the back and passed through corresponding loops 34 at the upper corners of the bib. The tapes are finally tied behind the neck. In some applications further pockets 35 may be attached to the bib for other types of gas absorber.

1. A portable gas sampler apparatus, including a sampler tube mounted on a head band and through which air or gas may be drawn, the tube, when the apparatus is in use, being disposed adjacent the nose and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Gas pollution sampling This invention relates to environmental pollution measurement, and in particular to a portable apparatus for detecting and measuring pollutants. Control and measurement of environmental pollution involve various techniques and sampling procedures dependant on the nature and concentration of the pollutant involved. Where the pollution is related to the specific exposure of personnel to noxious gases, vapours, or dust particles, it is generally necessary to provide a portable sampling apparatus for monitoring the pollutant. A number of systems have been devised for this purpose. Some of these have an adjustable harness arrangement for filament to the person exposed, whilst others are simply affixed to the clothing. These previously described arrangements suffer from a number of disadvantages. In particular, such arrangements are often unsatisfactory where a concentration gradient of a pollutant exists. Thus, a truly representative sample of the pollutant can be obtained only from the breathing zone of the person exposed to the pollutant, i.e. any sampling device must be adjacent the nose and mouth of that person. Taking a breathing zone sample is usually achieved by attaching a sample device on the shoulder of the person exposed to the pollutant, and in some cases extending a probe close to the nose and mouth. One serious disadvantage of such an arrangement is that, due to movements of the head of the person, the probe is not in a constant position in relation to the nose and mouth. In cases of high concentration gradients of pollutants, results may be obtained which are at considerable variance with the actual exposure experienced by the person to whom the apparatus is fitted. The object of the invention is to minimise or to overcome these disadvantages. According to the invention there is provided a portable gas sampler apparatus, including a sample tube mounted on a head band and through which air or gas may be drawn, the tube, when the apparatus is in use, being disposed adjacent the nose and mouth of a wearer, and a gas absorber cell coupled to the sampler tube via a flexible tube. According to the invention there is further provided agas sampler apparatus as claimed in claim 1, and which further includes a flexible bib having a pocket for receiving the gas absorber cell and provided with means whereby the bib may be affixed to the upper chest of the wearer. An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure f is a plan view of the head-set sample probe unit of the gas sampling arrangement. Figure 2 is a cross-sectional view of the gas absorber cell of the sampling arrangement. Figure 3 shows a bib whereby the absorber cell of Fig. 2 may be mounted on the upper portion of the body. Referring to Fig. 1, the head-set sampling device forming the sensor portion of the arrangement includes a lightweight headband 11 to one side of which a plastics pad 1 2 is fitted to steady the headband 11 on the head of the wearer. To the other side of the headband is fitted a metal or plastics disc 1 3 provided with a foamed pad 14 and on which a stainless steel tube 1 5 is mounted. The tube 1 5 is curved to follow the contours of the wearer's face such that the end 1 6 of the tube is adjacent the nose and mouth. In some applications the end 1 6 of the tube 1 5 may be fitted with a filter capsule 1 7 e.g. for taking dust samples.In use, air is drawn with the end 1 6 of the tube 1 5 and through the tube via a flexible tube (not shown) to the gas absorber cell 1 8 (Fig. 2). The absorbtion cell 1 8 of Fig. 2 is of the fritted glass type and includes a glass container through the upper wall of which an inlet tube 21 is sealed the inner end of the tube 21 is flared to form a cone 22 which is covered by a porous glass frit 23. An outlet tube 24 provides a means of drawing a gas or air through the cell. In use the cell 1 8 is approximately quarter filled with a suitable liquid reagent for the pollutant gas to be absorbed. Advantageously the wall of the cell 1 8 may be indented below the outlet tube 23 to form a splash guard 25 to prevent loss of the reagent in the form of spray. In use a suction tube (not shown) is attached to the tube 24 to draw air or gas through the apparatus. Referring now to Fig. 3, the cell 1 8 is supported in a pocket 31 on a bib 32 formed from a flexible plastics material such as polyethylene or plasticised polyvinyl chloride (PVC). The bib 32 is secured to the upper chest by two tapes 33 passing from the lower corners of the bib beneath the arms of the wearer, crossed at the back and passed through corresponding loops 34 at the upper corners of the bib. The tapes are finally tied behind the neck. In some applications further pockets 35 may be attached to the bib for other types of gas absorber. CLAIMS

1. A portable gas sampler apparatus, including a sampler tube mounted on a head band and through which air or gas may be drawn, the tube, when the apparatus is in use, being disposed adjacent the nose and mouth of a wearer, and a gas absorber cell coupled to the sampler tube via a flexible tube.

2. A gas sampler apparatus as claimed in claim 1, and which further includes a flexible plastics bib having a pocket for receiving the gas absorber cell and provided with means whereby the bib may be affixed to the upper chest of the wearer.

3. A portable gas sampler apparatus, including a headband on which a metal or plastics sampler tube dismounted, the tube being bent so as to follow the contours of the human face and having an opening adjacent the nose and mouth of a wearer, a gas absorber cell having an inlet coupled to the sampler tube via a flexible plastics tube and having an outlet to which suction may be applied so as to draw air or gas via the sampler tube through the absorber cell, and a flexible plastics bib having a pocket for receiving the gas absorber cell and provided with means whereby the bib may be affixed to the upper chest of the wearer.

4. A gas sampler apparatus as claimed in any one of claims 1 to 3, and wherein the sampler tube is provided with a dust filter.

5. A gas sampler apparatus as claimed in any one of claims 2 to 4, and wherein the bib is provided with one or more further pockets for receiving one or more further gas detectors.

6. A gas sampler apparatus substantially as described herein with reference to the accompanying drawings.

7. A gas sampling process substantially as described herein with reference to the accompanying drawings.