most advanced types of shelters
The most sophisticated types of shelters are all kinds of casings, completely isolating the source of hazards. Shelter-shrouds on the basis of their actions can be divided into the following groups:
a) The shelter-sheaths encase himself in a car or a vehicle (car or vehicle maintenance is conducted through openings);
b) cover type cabinet, designed for manual operation with a source of harmful substances, contained within the cabinet;
c) the type of shelter showcase for handmade placed in them sources of harmful substances, usually small-sized in height;
r)-cover canopies having no front wall, which are designed for manual work with small-sized products;
e) the shelter boxes that do not have open apertures and adapted for manual work with sleeves with gloves built into the front wall, or manipulators;
e) housings, harboring only the part of machinery or apparatus, where there is a source of hazards.
From the standpoint of the most sophisticated ventilation shrouds, all harboring a machine or device. Experience in designing ventilation systems in many industries can say that in most cases can be completely hide even the most complex and cumbersome apparatus and machines.
Fig. 4 shows a sketch of the casing, completely harboring poluzavodskuyu furnace systems. Folding of the shell consists of removable boards (here, such panels twelve). Panels and doors are made of transparent plastic. The enclosure features a frame made of angle steel, which is based on its stationary cover. In this case, the casing is made detachable to allow repairs and rewiring the furnace during operation.
Collapsible enclosure with hinged shutters (boards) are well paid off for the shelter of such devices as nutch filters. Here, the housing must be collapsible to be able to change the filter cloth. In the collapsible enclosure can also enter a filter press. Since their service is at the end of the filtration process and evolution stops unhealthy, then by this point guard understands.
Quite varied, depending on destination design hoods. These designs are given in references on ventilation.
Regardless of the design and purpose of his hood openings must be met so that staff in no way could get his head inside the cabinet. Otherwise, the worker breathing zone will get concentrated hazard. Due to the depth of said cabinet cover must not exceed 700 mm, ie, the length of human hands.
Consider the conventional laboratory cabinet having two lifting glazed doors. If the amount of air removed from the cabinet, to count on full disclosure of both doors, then this will lead to excessive air change, especially if a lot of cabinets. Under the terms of the work rarely requires the full opening of both doors, and hence one can expect cabinet to open one or both openings of the opening half.
However, very often due to inattention open both doors. This leads to an unwanted consequences, if not in the lab, in the neighboring group when drawing from the cabinets. Consequently, it is necessary just to be blocking the doors.
Shelter showcase type (glazed panels) represent the low fume cupboards with glazed top cover, located below the head of the worker (Fig. 5). Through the glass surfaces (glass can be organic) business sees what is happening inside the cabinet.
When designing a display case cover needed depending on the technology for convenience, think carefully about its size.
Fig. 6. Boxing for work with radioactive substances
1 - sleeves with gloves, 2 - sight glass, 3 - prechamber 4 - filters
Shelter-visors do not have a glazed upper lid. Work looks inside the shelter through the opening along the entire front cover. Height of the opening is usually made of 400 - 600 mm.
Shelter boxes that do not have open apertures, used to work with radioactive dust-forming substances, as well as in packaging particularly toxic powders. A characteristic feature is the presence of boxes built by rubber sleeves and gloves (or paddle), as well as a special pre-combustion chamber, which is used to boot box and remove it from the processed materials. Pre-combustion chamber separated from the box sealed door. From prechamber also produced air exhaust.
Scheme box for work with radioactive substances is shown in Fig. 6.
Casings, harboring only a part of machinery or apparatus, are most common when dealing with dust. An example is the case, harboring Rough-grinding abrasive wheel and serving to capture the directional dust plume.
Full kapsyulyatsiya apparatus that allows a particular toxic hazard (or working under high pressure) is achieved by putting her and their piping in a closed-room cabin in which the staff comes periodically, using the means of individual protection from hazards. These funds are used respirators or masks-fed them fresh air. Management of equipment driven out of the cabin in a special corridor, which moves the supply air.
Fig. 7. Layout of cabins for the equipment under particularly toxic hazard
1 - self-closing of the lattice, 2 - furnace, 3 - Controls 4 - ventilation, 5 - forced ventilation
Cabins apparatus ventilated. Exhaust ventilation or general exchange-zonal (much less often - with local suction). Cab must always be under negative pressure, feed them, even in small amounts of forced flow is strictly contraindicated. Air, compensating for the hood of the cab, enters into them by vacuum through the special grating, or self-closing check valve.
Fig. 7 illustrates an exemplary layout of booths and "clean" corridors. Self grating installed in doors or walls of the cabin. In some cases, if the permissible drop in temperature in the cab or have large heat release may take the air is not pure corridor and directly outside.