Vacuum Cleaner

VACUUM CLEANER, an apparatus used for removing dust from surfaces or collecting it for the purpose of investigating air dustiness by means of aspiration. Vacuum cleaners are portable, transportable on carts, and stationary. Systems operating with air rarefaction (vacuum) and with increased pressure are distinguished. Portable vacuum cleaners are powered either by manual force or, more often, by electric current. Transportable and stationary vacuum cleaners are powered by electricity, sometimes by heat engines. The main components of a vacuum cleaner are as follows: 1) rubber hoses with a metal nozzle applied to the surface being cleaned of dust, 2) a metal reservoir in which air rarefaction or compression is produced by means of a fan, turbine, or bellows, 3) an engine (electric or gas motor), 4) a receptacle for the collected or removed dust. Metal nozzles, usually made of aluminum, come in various shapes, mostly in the form of a spatula from 7 to 50 cm in width; along the edge [Figure 1. Cleaning dust from a dress with a vacuum cleaner "Vampir"] of it, applied to the dusty surface

a slit of ¹/₂-1 cm is cut to create a strong air current in order to detach dust particles from objects and carry them along the hose to a filter or into a special receptacle. For napped surfaces, the nozzles are made smooth around the slit; for smooth surfaces, they are equipped around the slit with a brush of greater or lesser elasticity and hair length. This brush mechanically facilitates the release and removal of dust particles. Sometimes the nozzle [Figure 2. Portable vacuum cleaner "Vampir": 1-smooth nozzle; 2-flexible metal hose; 3-fan; 4-motor; 5-dust collector; 6-nozzle with brush; 7-cord to plug; 8-handle with switch] has the shape of a narrow hollow tube with a longitudinal slit on one side for extracting dust from

narrow places, for example from books on shelves, from the space above radiators, from a dress hanging in a wardrobe, etc. The nozzle is hermetically fitted onto a hollow metal handle, with the help of which one can, without bending over and without the help of

a ladder, clean the floor, walls, ceiling, etc. The handle connects tightly with a flexible rubber sleeve, which is sometimes enclosed in a flexible frame made of metal rings; the sleeve of varying length connects with the device for air rarefaction or with a reservoir for

[Figure 3. Transportable vacuum cleaner: 1-nozzle; 2-suction hose; 3-vessel for collecting dust; 4-reservoir with filters; 5-suction fan; 6-motor; 7-cord to plug. The suction load of the device is 60 m³ per hour. Electric motor of one horsepower. Dimensions of the device-90.0x43.5x70.0 cm. Weight-95 kg without accessories.]

compressed air. The connection of the sleeve to this mechanism can be either direct or, in stationary installations, by means of a network of iron pipes laid throughout the building. In the latter case, the machine for air rarefaction or compression is located in the basement floor. In portable apparatuses, the dust on the way to the fan or through the bellows first passes through a filter in the form of two bags—one cloth and the other linen. In other systems, the dust with the air is pushed through water, where it is retained (Figs. 1-6). Since, over time, the filters become heavily clogged with dust and impede the movement of air,

[Figure 4. Stationary vacuum cleaner: 1-suction pipe; 2-reservoir for collecting dust; 3-reservoir with filters; 4-motor; 5-fan; 6-pipe expelling air; 7-switch

a device is arranged for shaking the bags to drop the dust into the underlying reservoir, to extract it from there and burn it, or to wash the dust from this reservoir with a jet of tap water into the sewage system. Stationary vacuum cleaners more often work with compressed air. The design of the nozzles in these systems is such that a jet of compressed air enters it through a special central tube, branching in the nozzle into two jets; of these, one exits through small openings in the mouthpiece and tears the dust particles from the place of their attachment, and the other turns near the slit back into the peripheral tube and creates rarefaction in it. In this way, the pressure difference on the dust particles is increased and the cleaning effect is greater

[Figure 5. Diagram of a stationary vacuum cleaner: A-suction pipe; B-reservoir for collecting dust; V-reservoir with filters; G-dust pump; D-pipe expelling air; E-pipe from water supply; Zh-pipe for washing dust into the sewage system; Z-electric motor.]

there is a central installation pumping air into a reservoir with compressed air, from where iron pipes are laid underground to those tracks where carriages are placed for cleaning. In the Potsdam railway workshops (Germany), in special closed rooms, carriages are even cleaned mechanically on the outside by vacuum cleaners within no more than 10 minutes. In the skyscrapers of the USA, stationary vacuum cleaner installations are almost the rule. Many factories and plants in the USA and Germany are equipped with central vacuum cleaners, e.g., paint, textile, silk-spinning, cloth, tobacco, cement, bakeries, etc. (Fig. 7). Cleaning dust from libraries, offices, printing houses, hospitals, hos-

-pitals, hotels, etc., is also often performed by vacuum cleaners.

In the USSR, vacuum cleaners are still a rather rare phenomenon; after the revolution, they began to be installed for the purpose of sanitary labor protection in printing houses, on railways, etc. Experimental verification of the action of vacuum cleaners has been carried out repeatedly both abroad and in the USSR. Berghaus points out that with the help of a vacuum cleaner in a hotel room, already cleaned by the usual method, another 393 g of dust was removed within 1/2 hour, and in another room within 50 minutes another 651 g. Especially valuable during vacuum cleaner cleaning is that during its operation, dust is not raised into the air and cleaners do not touch it with their hands, as is the case with dry or wet cleaning with rags. Butyagin proved that 1/2 hour after the operation of a vacuum cleaner, the number of bacteria in the air is half as much as after ordinary cleaning with brushes and rags, and that the air expelled from the vacuum cleaner contains much fewer bacteria than the air entering it. Vacuum cleaning is at the same time to some extent a disinfection of the environment, and therefore represents one of the methods of combating infectious diseases. Ickert advises spending from 45 seconds to 1 minute on processing 1 m² of fabric materials with a vacuum cleaner when working with a wide nozzle. At the same time, it removes

[Figure 7. Cleaning a ceiling with a vacuum cleaner at a factory.]

up to 98% of dust and all bacteria. Cleaning with a vacuum cleaner, of course, does not exclude other methods of disinfection and floor washing; for wallpaper, it is the best method of cleaning walls. It is possible to recommend the vacuum cleaner also as a disinsection method for removing insects simultaneously with dust from walls, things, and clothing (Kischke). Karsten recommends the vacuum cleaner for removing moths and their larvae, for catching malaria mosquitoes from the walls of basements where they retreat for hibernation; moreover, he advises doing this at twilight, when the insects settle on the walls. He also points out the possibility of using the vacuum cleaner for spraying disinfectant solutions if the hose to the atomizer is connected to the opening expelling air from the vacuum cleaner, which can double the effect of cleaning premises. Taking into account that beating outerwear, blankets, upholstered furniture, and carpets in cities presents a difficult task in terms of choosing a suitable place, that often upholstered furniture cannot even be moved (e.g., in theaters), and considering the enormous economy of time, the completeness of cleaning all surfaces of a room, and the possibility of more frequent dust removal from it, it can be considered that vacuum cleaners will receive wide application in the USSR as sanitary installations of primary necessity. At the same time, however, it should be emphasized that as health measures for combating dust in an industrial environment, vacuum cleaners have only auxiliary significance.