Either of these separators will remove from 95% to 98% of the dirt that ordinarily comes to them through the pipe lines and are about equally efficient.
FIG. 69. PRIMARY SEPARATOR USED BY THE GENERAL COMPRESSED AIR AND VACUUM CLEANING COMPANY.
FIG. 70. PRIMARY SEPARATOR MADE BY THE BLAISDELL ENGINEERING COMPANY.
The separator illustrated in [Fig. 69] was used by the General Compressed Air and Vacuum Cleaning Company. The entering air is led to the center near the bottom and is then released through two branches curved to give the air a whirling motion. The clean air is removed from the center of the separator near the top. This separator is not as effective in its removal of dirt as either of the former types, owing to the entering air being introduced near the bottom. This tends to keep the air and the dust in the bottom of the separator continually stirred up, also the curved inlets give the air more of a radial than a tangential motion and there is less separation due to centrifugal action.
The separator illustrated in [Fig. 70] is made by the Blaisdell Engineering Company. In this separator the inner centrifugal cylinder of the Vacuum Cleaner Company’s separator is replaced by a spiral extending nearly to the outlet in the center of the top. This arrangement tends to prevent the reduction in the air velocity and to limit its effectiveness in the removal of dust.
Separators similar to the Sanitary separator have been manufactured by many firms producing vacuum cleaning systems. These all differ somewhat in details of construction but the principle involved, i. e., centrifugal force and reduction in air velocity, is the same in all cases.
With vacuum producers in which there are no close clearances or rubbing contacts, these are the only separators used. The finer particles of dust passing these separators are carried harmlessly through the vacuum producer and through the exhaust to the outer atmosphere or to the chimney or other flue where they are effectively sterilized.