The author’s ingenuity being about exhausted, he referred to the test of Mr. Stewart R. Miller in which quicksand which would pass a 50-mesh to the inch screen was used, a long-napped Brussels carpet being filled with 5¹⁄₂ oz. per square yard and cleaned with Types A and C renovators.
This test indicated that a nearer approach to the results in cleaning dirty carpets was possible with this substance than with any which the author had tried. The author repeated Mr. Miller’s test, using a Type F renovator, 10-in. × ³⁄₄-in. cleaning slot, and also a Type F¹ renovator, 15-in. × ¹⁄₄-in. to ³⁄₄-in. cleaning slot. In duplicating these tests the author was associated with Mr. E. L. Wilson, a graduate of the Institute, who was familiar with the methods used by Mr. Miller. With his assistance, the conditions of Mr. Miller’s tests were almost exactly duplicated. The results of Mr. Miller’s and the author’s tests are given in the [table] opposite, correction being made in the time of cleaning proportional to the size of carpets used, to allow the same time for cleaning 1 sq. yd. of carpet by each renovator.
TABLE 2.
Cleaning Tests of Carpets Filled with 5¹⁄₂ Oz. of Quicksand
per Square Yard of Carpet.
| Type of Renovator. | A | C | F | F¹ | ||||
|---|---|---|---|---|---|---|---|---|
| Vacuum in renovator, in. hg. | 4¹⁄₂ | 4 | 3¹⁄₂ | 3¹⁄₂ | ||||
| Air exhausted, cubic feet per minute | 27 | 44 | 59 | 54 | ||||
| Material removed, per cent. of total, 1 min. | 60 | 53 | 66 | 53 | ||||
| Material removed, per cent. of total, 2 min. | 75 | 65 | 83 | 75 | ||||
| Material removed, per cent. of total, 3 min. | 82 | 74 | 94 | 86 | ||||
| Material removed, per cent. of total, 4 min. | 87 | 82 | 100 | 94 | ||||
| Material removed, per cent. of total, 5 min. | 92 | 87 | —— | 100 | ||||
| Material removed, per cent. of total, 6 min. | 95 | 93 | —— | —— | ||||
| H. P. per ounce sand | 0. | 09 | 0. | 138 | 0. | 084 | 0. | 109 |
| Ounces sand per minute | 3. | 2 | 3. | 1 | 5. | 3 | 4. | 0 |
The results of these tests are shown graphically in [Fig. 18]. Comparison of these curves with the curves of cleaning dirty carpets ([Fig. 17]), shows a falling off in the efficiency of cleaning by Type A renovator while there is a gain in the efficiency in cleaning by all of the other types of renovators, Type C being now nearly as efficient as Type A, while Types F and F¹ renovators are now more efficient than Type A. This result must be due either to the increased quantity of material to be removed, 5¹⁄₂ oz. per square yard in case of the sand as against 2 oz. per square yard in case of the dirt, or else to the change in the character of the material removed, the sand having much sharper surfaces than would be encountered in case of dirt which must necessarily be ground under the feet before it reaches the carpet, or to the longer nap of the carpet.
FIG. 18. CLEANING TESTS OF CARPETS FILLED WITH QUICKSAND.
In order to determine the effect of the increase in the quantity of material on the results, the tests were repeated using 1 oz. of sand per square yard of carpet in each case, omitting the test on Type F¹ renovator.
These tests were made on a glue-sized back, short napped Brussels carpet, using as much sand as could readily be worked out of sight in this carpet. The results of tests are given in the following table:
TABLE 3.
Cleaning Tests Using 1 Ounce of Sand per Square Yard of Carpet.