[Fig. 22] shows the results of tests by Mr. Reeve using a renovator of Type D, having a double cleaning slot, and indicate that this type of cleaner is not as efficient as Type A and is affected more by the canting of the handle from the best angle for cleaning.
The above mentioned tests are published through the courtesy of Messrs. Ewing and Ewing, attorneys for the Vacuum Clean Cleaner Company.
Since the method of making these tests is entirely different from that used by the author, a comparison of the results, with any assurance that the same conditions existed in both cases, is impossible. It occurred to the author that a comparison of the results of the tests by Mr. Reeve, using a carpet artificially filled with actual dirt taken from carpets, with the tests made by the author on carpets naturally soiled, would tend to show if equal results could be obtained by a vacuum cleaner by artificially soiling a carpet with dirt taken from another carpet, and in cleaning a carpet naturally soiled.
FIG. 22. TESTS BY MR. REEVE, USING TYPE D RENOVATOR.
The author has reduced these results to the same units of time per square yard of carpet cleaned as in the test on the Philadelphia carpet with the small-sized Type A renovator (11-in. × ¹⁄₂-in. face and 10-in. × ³⁄₁₆-in. cleaning slot). The carpet used by the author contained 6 sq. yds. and was held in cleaning by a weight at each corner, while the carpet used by Mr. Reeve was ³⁄₄ yd. wide and cleaned for approximately one yard of its length, the relative size being 1 to 8. The time of cleaning was 6 min. in the author’s test which would correspond to ³⁄₄-min. cleaning in Mr. Reeve’s test, or 30 strokes of the sweeper. The total dust in the carpet in Mr. Reeve’s test was ⁵⁄₄₀ lbs., or 2.66 oz. per square yard, and his test is compared with the author’s test with the carpet containing 2 oz. per square yard. Calculation of the per cent. of total dirt removed in each 5 strokes of the sweeper in Mr. Reeve’s test, and a comparison of the per cent. of dirt removed in each one minute’s test by the author are given below:
TABLE 4.
Comparison of Tests Made by Mr. Reeve and by the Author.
| Mr. Reeve’s Test. | Author’s Test. | ||
|---|---|---|---|
| Strokes. | Material removed, per cent. of total. | Minutes. | Material removed, per cent. of total. |
| 5 | 62 | 1 | 60 |
| 10 | 80 | 2 | 81 |
| 15 | 89 | 3 | 90 |
| 20 | 94 | 4 | 95 |
| 25 | 97 | 5 | 98 |
| 30 | 99 | 6 | 100 |
The above comparison was made using curve A, [Fig. 20], with the sweeper at its best angle with the floor. The close agreement of the two tests indicates that a carpet artificially soiled with dirt actually removed from another carpet by a vacuum cleaner is as difficult to remove as dirt which has been worked into a carpet by ordinary daily use. This condition does not result when any other substance is used to artificially soil the carpet, as will readily be seen by reference to the tests of carpets filled with sand and other substances which have been described in this chapter.
A comparative test of three different renovators was recently made by the author. Renovator No. 1 had a cleaning slot 14 in. long by ³⁄₄ in. wide, the edges of the slot being a segment of a circle having a ¹⁄₈-in. radius. This form of cleaning surface allows very small area of contact with the surface cleaned and permits the admission of large air volumes, about 56 cu. ft., with 2-in. vacuum. It is practically a Type F renovator, similar to that used in the tests at Hartford.