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Drive Housing and Assemblies
Bowl shell assembly - 14003_119

Aviation Boatswains Mate F - Aviation theories and other practices
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inside the drive housing and the other end is outside. The inside end is geared to the worm wheel gear; therefore, when the direct drive assembly rotates, the speed counter shaft rotates. The speed counter, but, rotates at a much slower rate because of the gear ratio. The outside end of the speed counter shaft is covered by an attached cap. The cap has a raised bump on one side of its top. Bowl speed is determined by the operator who places his finger on the outer edge of the cap and then counts the number of times the raised bump touches his finger in 1 minute. During full bowl rpm, the count should be between 146 and 150 times per minute. Because of the gear ratio, the drive motor rotates at 1,770 rpm, the bowl rotates at 4,100 rpm, and the speed counter rotates at 146 to 150 rpm. A handbrake (fig. 4-32) is provided to stop the purifier. This brake is for emergency use only. It consists of a spring- loaded brakeshoe and an eccentric handle. The brakeshoe has a replaceable section of bonded brake lining. When the handle is down, the brake is off. When the handle is raised to the up position, the brake is on. In the on position, the spring forces the brakeshoe and lining against the outer surface of the brake drum. Friction, thus created, causes the purifier to come to a stop. In the base of the drive housing is an oil sump for the oil lubrication system (fig. 4-33). All the bearings on the spindle and drive shaft are lubricated by this oil. The drive housing is divided into two compartments. One of these compartments contains the direct drive assembly coupling and the other contains the gears and bearings that are lubricated by oil. A metal partition separates the two compartments. The direct drive shaft passes through this partition and a gasket is installed around the shaft to prevent oil from entering the direct drive coupling compartment. The worm wheel gear on the drive shaft is partially submerged in the oil. Rotation of this gear splashes the oil about within the oil Figure 4-32.—Brake assembly. Figure 4-33.—Oil lubrication system. lubrication compartment, thus supplying oil to the bearings and gears. The oil sump holds from 8 to 8 1/2 quarts of grade 90 gear oil. Proper oil level is determined by a circular sight glass on the side of the drive housing. The glass retaining ring has two inscribed lines to indicate proper oil level. The white, top line, is the high or full oil level. The red, bottom line, is the low oil level mark. On some installations where the oil sight glass could not be seen easily in its normal position, the sight glass has been extended out and turned to give a clear view to the operator, or a dip stick has been added to the oil filler cap. The dip stick has two marks. The lower mark indicates lubricating oil should be added. Fill to the upper mark. To check the oil level, pull the stick completely out through the cap. Wipe with a clean, dry rag. Push the stick all the way in through the cap and pull it out again to read. Be sure the stick always rests on the cap. An oil fill cap is located near the top of the drive housing. An oil drain plug is at the base of the oil sump. Bowl Shell Assembly The bowl shell assembly (fig. 4-34) provides the working area for separation of contaminants from JP- 5. The entire bowl shell assembly sits on top of the spindle assembly. The spindle assembly causes the bowl shell assembly to rotate. This rotation is transmitted to the fuel, thus providing the necessary centrifugal force to cause separation to take place. During operation, the bowl shell assembly contains a fresh water seal to prevent loss of the JP-5. Most of the separated solids and emulsions are retained within the bowl shell assembly, but are completely removed from the line of flow of the liquids. 4-38







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