40 AIR COMPRESSORS 



Any steam leakage that can reach the air inlet of the com- 

 pressor should be promptly repaired as such increases the 

 danger of water entering the brake pipe. 



Keeping the suction strainer clean is of the utmost importance 

 as even a slightly clogged strainer will greatly reduce the 

 capacity where the speed is at all fast. A seriously or com- 

 pletely obstructed strainer, as by accumulated frost, aggra 

 vated by rising steam, will increase the compressor speed and 

 will also be indicated by inability to raise or maintain the 

 desired pressure. 



It is an aid to good operation to clean the air cylinder and 

 its passages thoroughly at least three or four times a year, 

 by circulating through them a hot solution of lye or potash. 

 This should always be followed by sufficient clean, hot water 

 to thoroughly rinse out the cylinder and passages, after which 

 a liberal supply of valve oil should be given the cylinder. Suit- 

 able tanks and connections for performing this operation can 

 easily be arranged in portable form. Never put kerosene oil 

 in the air cylinder to clean it. 



LUBRICATING SIMPLE COMPRESSORS 

 Steam Cylinder. A sufficient quantity of good valve oil 

 should be used in the steam cylinder to keep the parts well 

 lubricated and prevent groaning. The quantity of oil neces- 

 sary will depend on the kind of oil used, and also on the pump 

 itself, as some pumps require more than others. If the pump 

 groans constantly, and the pump exhaust or the drain cocks 

 show that considerable water is being worked through the 

 steam cylinder, its dry pipe should be examined for leaks 

 that might allow water to reach the pump and wash out 

 the oil. 



Air Cylinder. The quantity of oil to be used in the air 

 cylinder depends to a great extent on the pump, but in any 

 case it should be used very sparingly. The amount should 

 only be sufficient to keep the packing rings free and prevent 

 the cylinder walls from cutting. If too much is used, a gummy 

 deposit is formed in the air cylinder and air passages, and on 

 the air valves, which tends to cause heating; also, oil works 

 back into the brake valve and triples and causes them to 



