Receiving hood

Receiving hood An extract hood in the immediate vicinity of a process that extracts the generated pollutants in an effective manner. 

A receiving hood is an exterior hood that uses the discharge motion of the contaminant for collection. 

A local exhaust system is used to collect air contaminants at the source, as contrasted with general ventilation, which allows the contaminant to spread throughout the workroom, later to be diluted by exhausting quantities of air from the room. Local exhaust may be achieved using an enclosure, a receiving hood, or an exterior hood. Exhaust Ventilation... 

Three types of hoods are used in these systems capture hoods, enclosing hoods and receiving hoods. 

Many operations involve the use of solvent tanks for surface treatment, metal cleaning, degreasing, stripping and acid treatment. Canopy receiving hoods are sometimes utilized to collect contaminants from some of these operations however, they are most effective when used for hot processes. The engineer must consider air movement and currents which may allow the release of the contaminant into the workplace when designing such a system. In addition, some processes may involve the movement of workers heads over the tank or the lifting of... 

Enclosure hood Receiving hood Capturing hood... 

Hoods can be classified conveniendy into three broad groups enclosures, receiving hoods, and exterior hoods. Booths such as the common spraying-painting enclosure are a special case of enclosing hoods. 

Cross-linked polyethylene-based compounds that contain dame-retardant components and compounds based on PVC cross-linked by radiation have also received high temperature rating. They find use not only in appHance wires but also in manufacturing under-the-hood automotive wires. 

As soon as the receiver containing the methyl 11 thiurn solution has been removed and stoppered, the residual solids in the reaction flask and the filtration apparatus should be rinsed Into another receiver with anhydrous ether under an atmosphere of argon or nitrogen. The ether slurry of solids, which may contain some unchanged lithium metal, should be treated cautiously in a hood with t-butyl alcohol to consume any residual lithium metal before the mixture is discarded. 

Receptor hoods, also called canopy hoods, are designed to capture contaminants given off by heated processes. They take advantage of the thermal updraft caused by such processes by placing the hood in the path of the updraft, they receive the exhaust and capture the contaminants. 

Downdraft hood A hood positioned under a process that receives gases, vapors or dusts from the source above. 

Hood, receiving A hood intended to receive generated contaminants at some distance from the source. 

A receptor hood receives a contaminant driven into it by the source of generation. The flowrate needs to ensure that the hood is emptied more rapidly than the process fills it and to overcome draughts. No operator should work between the hood and the source of the contaminants. 

She was right. If Edward were not alone, it would be an insult to me that the whole palace would know of by the morning. You may come with me, and ask if His Grace will receive you. I shall be hooded they will not think that it might be the Queen. And if he receives you, I shall enter too. ... 

Bromine (A.C.S. certified) was purchased from Aldrich Chemical Company Inc., used as received, and measured with a 50-mL graduated cylinder in the hood. 

The required amount of HCN was freshly distilled in a well-ventilated fume hood. Sodium cyanide (128 g) was dissolved in deionized water (320 mL) and 5 m sulfuric acid (320 mL) was added dropwise within the distillation equipment and the resulting solution was heated up to 75 °C. The hydrogen cyanide was condensed immediately in a receiving flask cooled to 5 °C. Total yield of hydrogen cyanide 68 mL. 

Caution Triphenylarsine is highly toxic and must be handled with gloves in a well-ventilated hood. It was purchased from Aldrich Chemical Company, Inc., and used as received. 

Fifty grams of powdered sulfur are introduced into the flask and heated to 150 °C in an oil bath under the hood while a moderately rapid stream (about 5 bubbles/sec) of dry chlorine is led over the molten sulfur. The crude orange-red product distills rapidly into the receiver. The chlorination requires about two hours and is stopped when only a very small amount of sulfur remains in the reaction flask. About 5-8g of sulfur are added to the crude condensate to combine with the excess of dissolved chlorine a redistillation yields over 90% of the dark yellow chloride boiling at 137-140°C. Large amounts of low-boiling materials must be distilled again from a little sulfur. To obtain a pure product, the material may be fractionated once more or distilled in vacuo b.p. 29-30°C (12mm). 

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