Know Your Air Brakes
Page 46
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Part 22—Care and Maintenance of v,,...., I Air Tanks and Reservoirs BY HANDYMAN
A LTHOUGH air reservoirs have been M. mentioned in earlier articles, it rill be as well to have a general look ow at this section and its several points if interest. Accepting that a reservoir has
primary function, which is to store Lir in sufficient quantity to permit several rake applications and serve other units Llso, there is a secondary function which s also important. This is to provide a 'lace where hot air from the compresser an cool and allow oil and water vapours o condense.
This point is not always understood, and iater found in air reservoirs is often considered to be due solely to weather conditions. However, this is not quite true as it is the compression and later cooling of air that produces the water, although humidity does influence the situation. The oil content is, of course, from excessive compressor lubrication. Therefore it will be easier to understand that water will always collect in the air reservoirs, and draining should be made a daily duty.
Any air reservoir can be a danger if weakened or poorly constructed, and on the vehicle system there is no easy means of internal inspection. Vehicle reservoirs are made of good quality sheet steel, with electrically welded seams. Any connections to the reservoir must be strong, whether for pipe or bolt fixing, and for this duty ferrules are used and welded in securely, being tapped for the appropriate fitting. On certain vehicles, both truck and bus, twin tanks will be found, sited in tandem. There is a technical reason for this: apart from the capacity angle, the first tank from the compressor will collect all the condensation, and this is often known as the wet tank. It will be noted on twin-tank systems that the air is taken from the second tank (which is known as the dry tank), but just the same each tank should have daily draining attention.
It should be remembered that draining is not successfully accomplished by simply opening the tap and letting air blast out. The tank will only drain fully when all air has escaped; therefore, a few minutes may be required with open taps to clear the water.