FIG. 34. UPHOLSTERY RENOVATOR WITH NARROW SLOTS TO PREVENT DAMAGE TO FURNITURE.
However, if the exhauster be of such characteristics and the hose and pipe lines be so proportioned that there is practically a constant vacuum in the renovator, regardless of the quantity of air passing, and provided this vacuum is not allowed to exceed 5 or 6 in. of mercury, no disastrous effects will be experienced in cleaning light-weight fabrics with a straight-slot renovator having a cleaning slot not over ¹⁄₄ in. wide. The use of this type, in connection with a system having the above-described characteristics, is recommended whenever rapid cleaning is desired.
Upholstery renovators make the most serviceable clothing cleaners, while a small type of bristle brush, not over 4 in. long and not over ³⁄₄ in. wide, makes the most serviceable hat brush.
FIG. 35. ANOTHER TYPE OF UPHOLSTERY RENOVATOR WITH SHORT SLOTS.
An important form of renovator is that used for cleaning between the sections and behind heating radiators. A piece of tubing, flattened at its outer end, is by far the most effective device for this purpose. This renovator, in connection with the hat brush tool, makes the two best renovators for use in the library, effective cleaning being possible with not more than 20 cu. ft. of air per minute, but much faster work can be done with larger quantities.
FIG. 36. HAND BRUSH TYPE OF RENOVATOR.
Another form of renovator sometimes furnished is the small hand brush. This is a bristle brush, approximately 8 in. long and 2 in. wide, with the hose connection made into one end of same, as illustrated in [Fig. 36]. This renovator is useful for cleaning wooden furniture, shelves, tables, and other horizontal surfaces at about hand height, but, owing to the tendency of the air to short circuit in its way to the body of the renovator, it will not do effective work with small quantities of air.