Flammable gases tubing

Flammable atmospheres can be assessed using portable gas chromatographs or, for selected compounds, by colour indicator tubes. More commonly, use is made of explos-imeters fitted with Pellistors (e.g. platinum wire encased in beads of refractory material). The beads are arranged in a Wheatstone bridge circuit. The flammable gas is oxidized on the heated catalytic element, causing the electrical resistance to alter relative to the reference. Instruments are calibrated for specific compounds in terms of 0—100% of their lower flammable limit. Recalibration or application of correction factors is required for different gases. Points to consider are listed in Table 9.10. 

A good chemist takes pride in his apparatus. He diameter of 6 millimeters lit snugly into the holes in makes it. with great, care—not just for looks but. the usual rubber stoppers. Rubber tubing of an in-more important, for safety. An apparatus that leaks side diameter of % fits over the 6mm glass tubes, flammable gas can be very dangerous. To determine the right size stoppers to use in the... 

If you have pressurized air in your lab, you can use a motorless hot air gun. These units are smaller than standard hot air guns and are typically about the size of small home hair dryers. Motoiiess hot air guns only require heating filaments because they do not have fans. To use one, a flexible tube is attached to an air supply and the hot air gun. If your lab does not have plumbed-in compressed air, or the location of your outlet is too far away from where you want to use the hot air gun, another option is to use a compressed gas tank of air. Do not use compressed oxygen or any flammable gas for the air supply. You could use an inert gas, such as nitrogen for your air supply, but it would be costly. 

Some vaporization may occur in the spray chamber, and the largest droplets will condense onto the walls of the chamber and go to waste. The waste tube leads to a liquid trap which prevents the gases from escaping and ensures a small steady excess of pressure in the spray chamber. Because a relatively large volume of flammable gas is in the chamber, it is a potential source of danger. Modern AA instruments, however, are equipped with gas control systems which give protection from flashback of the flame. Spoilers are often employed inside the spray chamber to improve the change between the sample mist and the tube walls. 

Inspect for improper gas tubing, and faulty valve and regulator installations. These types of errors can he difficult to identify but are important because they pose significant hazards in systems where toxic or flammable gases are used. The typical items to inspect... 

After the manhole cover is removed, continue to test for combustible gas by lowering the sampling tube within 12 inches of the manhole or vault floor. If no flammable gas is found, purge the manhole with the power blower for the period of time based on the blower capacity and manhole configuration, following company procedures. 

As in the case of any flammable gas, never use a flame in trying to detect carbon monoxide leaks. Portable detection equipment or the formation of bubbles by a soapy solution applied to a suspected area will indicate leaks. Carbon monoxide alarm detectors must be installed in all indoor areas in which the gas is regularly used in more than small laboratory amounts. Colorimetric sniffer tubes are also utilized for detection of carbon monoxide. Samples of atmospheric air containing carbon monoxide are aspirated through such tubes. 

Methyl chloride may be absorbed from leaking cylinders into a suitable organic solvent such as xylene, toluene, benzene, or chloroform after attachment of the appropriate regulator and flexible tubing. It may subsequently be recovered for use, or it may be disposed of in a manner suitable for disposal of a flammable gas and in accordance with federal, state or provincial, and local regulations [4]. 

The cathode of the lamp which is filled with Ar or Ne at low pressure, sputters when a H.V. is applied to the electrodes. Collision of the noble gas and metal atoms excite the latter then they emit radiation in the visible/u.v. region of the spectrum. The metal compound in the sample to be analysed, dissolved in a suitable solvent, has to be transformed to a mist of gaseous atoms. This is generally achieved by aspirating the solution into a nebuliser where a mist is sprayed in a flame of a flammable gas widi an oxidising gas. The gas mixture may pass through the nebuliser first or it may burn directly. Alternatively, furnace atomisers are used, when smaller volumes of test solutions can be handled. The solution is placed in a horizontal graphite tube or a carbon rod which are heated in an electric furnace. 

Storage and Shipment. VDF or HFC-1132a is stored and shipped in gas cylinders or high pressure tube trailers without polymerization inhibitor and is placarded as flammable compressed gas. Terpenes or quinones can be added to inhibit polymerization. Elf Atochem North America, Inc. and Ausimont USA, Inc. supply VDE in the United States other producers are in Japan and Europe. 

All precautions relating to compressed gas cylinders must be enforced—the cylinders must be secured to an immovable object, such as a wall they must have approved pressure regulators in place they must be transported on approved carts etc. Tubing and connectors must be free of gas leaks. There must be an independently vented fume hood in place over the flame to take care of toxic combustion products. Volatile flammable organic solvents and their vapors, such as ether and acetone, must not be present in the lab when the flame is lit. 

All manipulations are carried out under a nitrogen atmosphere using standard septum, syringe, and hypodermic tubing techniques.8 Caution. Since ethylene oxide is a colorless, extremely flammable, moderately toxic gas at room temperature and atmospheric pressure, all procedures except the final column chromatography are carried out in a well-ventilated hood. 

The reagent has b.p. 11 °C and is supplied either in 100-ml sealed tubes or in 100-ml cylinders equipped with an appropriate valve. The gas, which is highly flammable, has no very distinctive smell and must be regarded as a hazardous toxic reagent which must not be inhaled or allowed to come into contact with the skin and eyes. Precautions in the use of ethylene oxide are described in Expt 5.39, which may be regarded as typical. 

Following fires in which endotracheal tubes became ignited by surgical lasers or electrocautery in atmospheres enriched by oxygen and/or nitrous oxide, the flammability of PVC, silicone rubber and red rubber tubes in enriched atmospheres was studied [1], Ozonised oxygen was reacted with hydrogen at low pressure to generate hydroxyl radicals. Pressure in the apparatus was maintained by a vacuum pump protected from ozone by a tube of heated silver foil. On two occasions there was an explosion in the plastic vent pipe from the vacuum pump. The vent gas should have been outside explosive limits and the exact cause is not clear the editor suspects peroxide formation. 

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