| Size of Hose, In. Diameter. | Hose Length, in Feet. | ||||
|---|---|---|---|---|---|
| 100 | 75 | 50 | 25 | ||
| Cubic feet of free air per minute. | |||||
| 1 | 42 | 48 | 60 | 86 | |
| 1 | ¹⁄₄ | 62 | 72 | 86 | 125 |
| 1 | ¹⁄₂ | 95 | 110 | 135 | 190 |
The quantities given for the shorter hose lengths are higher than will be observed in actual practice, due to the increase in the pipe friction, which will depend on the length of the pipe lines. However, the results will illustrate the great increase in the quantity of air which will pass these bare floor brushes when operated on the same system with carpet renovators. If the same number of bare floor renovators are to be used at one time as there will be carpet renovators at some other time, that is, if the sweeper capacity must be maintained when using bare floor brushes as when using carpet renovators, a much larger air exhausting plant must be installed than would be necessary to operate that number of carpet renovators.
If it were possible to so arrange the schedule of cleaning operations that bare floor brushes were never used at the same time as carpet renovators, the vacuum at the machine might be reduced when operating the floor brushes to a point that would reduce the quantity of air passing to within the capacity of a machine designed to operate the same number of carpet renovators. Unfortunately, this condition rarely exists and, therefore, the vacuum must be maintained at the degree necessary to operate the carpet renovators that may be in use at the same time with the floor brushes.
It is also evident that if the length of hose used with bare floor brushes could be limited to the maximum ever used with the carpet renovators, a reduction in the capacity of the exhauster necessary could be made. This is another condition which the designer of the system cannot control.
Most Economical Hose Size for Carpet and Floor Renovators.
—The horse power required at the hose cock to operate the bare floor brushes with each of the different sizes and lengths of hose is:
TABLE 11.
Horse Power Required at Hose Cock to Operate
Bare Floor Brushes in Conjunction with Type A 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 | 0.92 | 1.06 | 1.27 | 1.38 |
| 1 | ¹⁄₂ | 1.15 | 1.32 | 1.62 | 2.28 |
This shows that where bare floor or wall brushes of the bristle type are used in conjunction with carpet renovators on any system and with Type A carpet renovator, 1¹⁄₄-in. diameter hose will give the lowest power consumption.
When either Type C or F renovator is used in combination with bristle-type brushes, the use of 1-in. diameter hose must be abandoned in lengths over 50 ft. and the vacuum at the hose cock must be maintained at 10 in. mercury. With 1¹⁄₄-in. hose, it will be necessary to maintain a vacuum at the hose cock of 7 in. mercury, and, with 1¹⁄₂-in. hose, 5 in. will be sufficient, provided we continue to use 100 ft. of hose in the case of the larger sizes. The free air passing a brush type of bare floor renovator under these conditions will be: