Fig. 214. Home-made vacuum cleaner
A single hand vacuum cleaner can be made from a powerful suction pump, as indicated in the sketch [Fig. 214]. This should be connected with a metallic box by means of a flexible armoured rubber hose, covered at the end with a piece of fine wire gauze to prevent large particles of dust, etc., being drawn into the pump. To another opening of the box should be fastened another flexible rubber tube, with a bell-shaped metal attachment at the end. The bell-shaped arrangement should be held closely to the carpet while the pump is in action. Within the box, the pipe to which the pump is attached should be bent upward, so that the rush of air shall not bring the dust with it; the object being to collect the dust in the box. A lid covers the box so that it can be emptied from time to time. The success of this arrangement depends on the strength of the pump; if it be a weak one, the inrush of air through the funnel will be so slight that the dust will not be raised.
Fig. 215. Metallic vacuum cleaner
Fig. 216. Simple vacuum cleaner
Rotary pumps are not satisfactory for vacuum cleaners. The best type for this work is a plunger, having a large displacement, with a comparatively short stroke in proportion to the diameter. A suitable pump is shown in the accompanying illustrations. [Fig. 214], shows the section of a single barrel, but should a greater supply be required, two barrels may be worked and connected as shown in [Fig. 216]. The pump is easily made, and of light construction. In [Fig. 215], is a brass cylinder with a flange at the bottom; this may be made out of a length of 3-inch brass tube with a flange cut from 1⁄8-inch sheet brass. The barrel is 8 inches long. G is the plunger, which may be constructed as a piston; but in the drawing, it is adapted to the arrangement that is shown in [Fig. 216]. With a piston will be required a guide for the rod at the top of the cylinder. E is a hydraulic cup, its leather kept soft and pliable by oiling. B is the base, which is hollow, and may be built up in sheet metal. At the centre at J, the base is divided into two compartments, one side being the inlet to the pump from the dust box, and the other in communication with the outlet valve C. C and D are two valves with guards. The valves are discs of very soft and pliable leather, well saturated with grease, D being the inlet from the dust box, and C the outlet to the atmosphere. The drawing clearly shows the construction of the other parts. [Fig. 216] shows two pumps fitted to one base and worked by a rocking lever; both pumps are in communication with the one inlet N. This arrangement of pumps is easy to work, portable, and well adapted to domestic purposes in cleaning carpets.