TABLE 12.
Free Air Passing Brush Type of Bare Floor Renovator
Operated in Conjunction with Type C Renovators.
| Size of Hose, In. Diameter. | Length, in Feet. | ||||
|---|---|---|---|---|---|
| 100 | 75 | 50 | 25 | ||
| Cubic feet of free air per minute. | |||||
| 1 | 42 | 48 | 60 | 86 | |
| 1 | ¹⁄₄ | 68 | 76 | 92 | 130 |
| 1 | ¹⁄₂ | 95 | 110 | 135 | 190 |
This shows an increase in the volume of air passing the floor brush with 1¹⁄₄-in. hose, while a higher vacuum is now carried at the hose cock than was necessary when Type A renovator was used in conjunction with the bristle-type of floor renovator. The horse power at the hose cock will now be:
TABLE 13.
Horse Power at Hose Cock with Brush Type of
Bare Floor Renovator Operated in Conjunction
with Type C Renovators.
| Size of Hose, In. Diameter. | Length, in Feet. | ||||
|---|---|---|---|---|---|
| 100 | 75 | 50 | 25 | ||
| Horse power at hose cock. | |||||
| 1 | 1.16 | 1.32 | 1.65 | 2.38 | |
| 1 | ¹⁄₄ | 1.19 | 1.36 | 1.60 | 2.26 |
| 1 | ¹⁄₂ | 1.15 | 1.32 | 1.62 | 2.28 |
With this combination of floor and carpet renovators, there is no difference in the power consumption when any one of the three sizes of hose is used. However, there is a considerable increase in the quantity of air passing the larger hose. This leads to the statement made by some manufacturers that this increase in air volume results in more efficient cleaning.
Tests given in [Chapter III] indicate that increase in air volume does not result in any more rapid or efficient cleaning of carpets. The results of actual use of the bare floor brush of the bristle type show no gain when cleaning bare floors. As stated in [Chapter IV], the felt-faced renovator, being more effective while it requires less air. In other words, it is the degree of vacuum within the cleaner and not the quantity of air which produces the cleaning in all cases where any degree of vacuum is possible. When intimate contact between the cleaner and the surface cleaned cannot be had, the volume of air determines the efficiency of cleaning. However, the author does not consider that an exhaustion of more than 60 to 70 cu. ft. of free air through cleaners of this type will increase the efficiency to such an extent as to justify the increase of power necessary to adapt a system to larger volumes.
The author considers that with a system in which brushes of the bristle type are to be used, the exhauster should have a capacity of 70 cu. ft. of free air per minute. Such a system is termed by the author a “large volume system,” as already mentioned in [Chapter IV].
When the felt-covered floor renovator is used instead of the brush, the vacuum within this renovator must not be permitted to rise above 2 in. or the operation of the renovator on the floor will be difficult. To accomplish this, it is necessary to provide openings in the ends of the cleaning slot, as has been explained in [Chapter IV]. If the vacuum at the hose cock be assumed as 10 in. with 1-in hose, 6 in. with 1¹⁄₄-in. hose, and 5 in. with 1¹⁄₂-in. hose, and the vacuum within the felt-covered floor renovator be maintained at 2 in. mercury the cubic feet of free air passing the renovator with the various sizes and lengths of hose will be:
TABLE 14.
Cubic Feet of Free Air Passing the Felt-Covered
Floor Renovators Operated in Conjunction with
Type A Renovators.