Vacuum cleaning systems

by M. S. Cooley

—The selection of renovators is the most important step in making up a vacuum cleaning system, as the entire makeup of the system, whether good or bad, is dependent on the proper selection of these tools. The carpet renovator is generally considered first in importance, because the cleaning of carpets has nearly always been found to be the principal field of usefulness in vacuum cleaning work. This is due, perhaps, largely to the fact that from the beginning of the art of vacuum cleaning, this function of the system has been held before the eyes of the public by the manufacturers of the earlier systems. Nearly all demonstrations of cleaning systems shown to the public consist of the removal of ordinary wheat flour from a carpet. The reason for this is two-fold; first, because it is the most striking demonstration to the eye of the layman, and, second, it is the easiest to accomplish with a small air displacement and small power, which was characteristic of the apparatus made by these manufacturers.

The author was at one time of the opinion that this function of the cleaning plant was given too much prominence by builders of systems having small air displacement, and letters were sent to the officials in charge of sixteen Government buildings in which vacuum cleaning systems were installed, asking them, among other questions, whether the cleaning system was used to any extent in cleaning bare floors, of which there were large areas, both wood and marble, in the buildings in question. The plants installed were of various makes, some of which maintained 12 in. mercury at the separator and used 1-in. hose, while about an equal number of others maintained 6 in. mercury at the separator and used 1¹⁄₂-in. hose. The answers showed that out of the sixteen buildings the cleaner was used on bare floors in but two of the buildings. One writer, who had a plant maintaining 6-in. vacuum, provided with Type F renovators and 1¹⁄₂-in. hose, stated that he had tried cleaning bare floors without success, as the renovator and hose became so clogged with litter as to be inoperative. The majority stated that the cleaning system displaced brooms on carpets and rugs and several stated that the cleaning system was used to advantage in cleaning walls, cases, pigeon holes and relief work.

This indicates that for the average office and departmental building the cleaning of carpets is the most important function of the vacuum cleaner. This is also true of residence work. Schools, department stores and manufacturing buildings contain very little floor space covered with carpets, and in buildings of this character the cleaning of bare floors is of the greatest importance. In such cases the efficiency of the carpet renovator can be sacrificed to a more efficient and economical operation of bare floor renovators.

In a building where carpet cleaning is an important function of the cleaning system, the selection of the carpet renovator is most important. Of all the various types of carpet renovators discussed in [Chapter III], only two need to be considered, Type A and Type F. Of these, Type A is superior in all respects except the picking up of large litter, and, unless the character of the material to be removed contains a large amount of material which can be picked up by Type F renovator that will not pass Type A, Type A renovator should always be used. Even when Type F renovators are desirable, the writer considers that the plant should still contain some Type A renovators for use in places where this unusual litter will not be encountered.

Among the bare floor renovators, described in [Chapter IV], only the one having a felt face, curved to permit its running over the dirt, is worthy of serious consideration. This renovator requires an inlet or vacuum breaker to keep same from sticking to the surface cleaned, the extent of such opening being dependent on the vacuum maintained in the carpet renovators, as explained in [Chapter VII].

When carpet cleaning is considered as of secondary importance to bare floor cleaning, the degree of vacuum maintained at the separators may be reduced to that which will produce a vacuum of 1 in. mercury at the bare floor renovator, allowing the vacuum maintained at the carpet renovator to be whatever the conditions of hose and pipe line will produce. Under such conditions, the area of the inrush or vacuum breaker in the bare floor renovator may be reduced considerably.

The use of brush renovators is dependent on the capacity of the air exhauster supplied, as explained in [Chapter VI]. If it is decided that brush renovators are necessary, then the “large volume” exhauster must be installed. The advisability of such installation is dependent on the time allowed for cleaning and the cost of the operators. In residences and small buildings where the cleaning operations can be done with one or even two domestics or laborers, very little, if any, saving in the wages of operators can be effected by increasing the rate at which the cleaning can be done. In such buildings a small-volume plant will be the most economical in first cost and operation. If such a plant is installed, the brush renovators should be omitted.

In cases where bare floor cleaning is the principal function of the cleaning system the extra quantity of air at the low vacuum necessary will not require much larger expenditure of power than that needed by the small-volume plants when maintaining sufficient vacuum for effective carpet cleaning and brush renovators should be provided with systems of this character.

Hose.

—In [Chapter VI] it is shown that when carpet renovators are operated efficiently in combination with bare floor renovators, 1¹⁄₄-in. hose will produce the best results with the lowest expenditure of power at the hose cock. In [Chapter VII] it is shown that with pipe lines of ordinary length 1¹⁄₄-in. hose also gives the best results, with the least expenditure of power at the separator, but that in cases of exceedingly long pipe lines, 1-in. hose will be the most economical. In a system where bare floor cleaning is the principal function, the vacuum to be maintained at the carpet renovator is no longer considered, and for such systems the largest hose which can easily be handled will cause the least hose friction and require the lowest vacuum at the hose cock. It is, therefore, the most economical to use on such a system. The author does not recommend the use of a hose larger than 1-³⁄₄-in. diameter for this type of plant.