—Having determined the efficiency of the various types of renovators when operated on dirty carpets, the author then attempted to find some substance easily obtained anywhere which could be used as a substitute for actual dirt, and which would give approximately equal results with these obtained on dirty carpets.
A test of this character was made by the author some time previous to the tests of dirty carpets and was made on a Wilton velvet rug of about 12 sq. yds. area. The material spread on same was ordinary wheat flour, as used in demonstrations, 3 lbs. of which were placed on the rug and rubbed in with sticks of wood as well as possible and the rug cleaned for three minutes, using a Type A renovator attached to the separator with 50 ft. of 1-in. diameter hose. The results were as follows:
| Vacuum at Separator, Ins. Mercury. | Per Cent. Dirt Removed. |
|---|---|
| 5 | 95 |
| 10 | 98 |
| 15 | 98 |
The vacuum at the renovator was not measured at the time of making this test and its amount is not exactly known, but further tests with this type of renovator under nearly the same conditions gave the following results:
| Vacuum at Hose Cock, Ins. Mercury. | Vacuum in Renovator, Ins. Mercury. | |
|---|---|---|
| 5 | 3 | |
| 10 | 6 | ¹⁄₂ |
| 15 | 9 | |
and it is probable that the vacuum at the renovator during these tests was approximately the same.
Comparison of the results of this test, in which 4 sq. yds. of carpet were cleaned per minute, with those of the tests of dirty carpets, in which only 1 sq. yd. was cleaned per minute, indicates that wheat flour is not a suitable substitute for dirt in making a carpet cleaning test.
The author, believing that flour is of sufficient fineness, but not of sufficient weight, tried Portland cement, which is very heavy and at the same time exceedingly fine, as a substitute for dirt in soiling carpets. The same carpet that had been cleaned in Philadelphia was used and 6¹⁄₂ oz. of cement was worked into the same. It was then cleaned with a Type C renovator, with a vacuum of 2¹⁄₂ in. hg. at the renovator and 95% of the cement was removed in two minutes’ cleaning, as against 59% of the dirt in the carpet when received.
Ordinary dirt, taken from some flower pots which had been left dry for some time, was then tried with the same carpet, using a Type C renovator and 1 in. hg. With this arrangement, 71¹⁄₂% of the dirt was removed in two minutes as against 52% of the dirt in the carpet as received.
This dirt was then mixed with water to a thin mud and spread over the carpet and the carpet dried before cleaning. Then 11¹⁄₄ oz. of this material was worked into 6 sq. yds. of carpet and a Type C renovator removed 100% of this in four minutes’ cleaning, with a vacuum of 2¹⁄₂ in. hg. at the tool as against 72% of the dirt in the carpet as received.