Shelter and local pumps
Umbrellas (caps), and their succinct versions - curtains (screens) - fairly common local shelter. However, the term "shelter" is not quite accurate, because the umbrella in the best case can be covered, but not to conceal the source of harm.
Umbrellas and curtains are used to locate hazards, have a tendency to climb. It would be wrong to use these shelters at hazard, looking to the floor.
In the absence of a tangible place of horizontal flow and intensive bubbling jet hazards umbrellas and curtains are a relatively reliable local shelters. However, they can recommend only two cases:
with non-toxic hazard, ie, when heat and vlagovydeleniyah;
for any harm (except for very toxic), accompanied by heat, creating a steady upward flow, but in the absence of permanent jobs at the source of hazards.
Under the scheme of execution umbrellas can be divided into the open on all sides (no overhangs) and a partially open - the one. two or three sides - from the overhang, as well as "visors" adjacent one side of the vertical wall of the equipment they serve. Umbrellas with overhangs, especially if the latter cover the sides of the source of harm, close to the shelter. They are more perfect than umbrellas without overhangs. But the main drawback - the need to find the head of the working of the pollutant source - is preserved and umbrellas with overhangs.
If the sources of hazards are numerous and are located in rows, and if there is regular and rapid allocation of pollutant instead of umbrellas installed curtains - dull and glazed. Glazed curtain favorably
of umbrellas, as it does not darken the room and more aesthetically acceptable.
Quite effective local suction are sucking the panel, for example type Cherpoberezhskogo. They are rectangular umbrellas, open part of which is positioned vertically or inclined to partially offset the living section. The latter consists of a series of parallel slits, the speed through which the aspirated 4-8 times faster than aspirated through the open hole umbrella.
Typically, the suction panel removes the harmful substances on the principle "from working." It is quite suitable for the individual suction (from a single location) for manual operations such as welding, gas welding, soldering, molding, blowing glass, etc. In other words, the suction panel, especially the slant, it is applicable for the removal of heated gases , smoke, mist, fumes. The panel is much less effective in removing dust, especially the relatively large, and quite unsuitable for the removal of the dust plume.
If the source of pollutant is of great horizontal extent with a small width, then the removal of gaseous pollutant can be used vertical or slightly sloping panel length. For uniformity of suction panel length is of several sections. It turns battery cover (Fig. 3). The length of its individual sections are usually no more than 1 m, the number of panels in the battery B-10 pieces.
Is very common suction side, which is a kind of slot suction. Onboard suction located along the long wall, which limits the mirror separation hazards (alongside the bath tub, gutters). Airborne pumps are also used in combination with a vent (pereduvkami) of different types.