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 Post subject: Lubricators
PostPosted: Sat May 23, 1998 2:17 am 

Well, now that I know all about sanding the flues, how about lubricating the cylinders. I know oil is injected into the steam to lubricate the cylinders, but I have several questions about this process:<p>Is the oil atomized in some way, injected?<br>How do you account for variables such as the volume or mass of steam entering the cylinder under different load and speed conditions? I.e., how do you vary the amount of lubricant and what controls it?<p>This is a very special kind of oil I presume? It can take being boiled and mixed with water and still lubricate.<p>How much oil is typically used? Don't recall seeing any large oil storage vessels on the engine proper (of course I missed the sand box in the cab). So, I would think a typical trip would only use a few gallons?<p>Does the oil getting exhausted with the steam tend to leave an oily mess on the rails? You can still see cinders on routes where coal burning engines used to run. Is there oil contamination too?<p>Just curious.<br>

 Post subject: Re: Lubricators
PostPosted: Sat May 23, 1998 7:58 am 

There are two common types of lubricators used on steam locomotives. Hydrostatic lubricators use condensed steam lifting oil under pressure into a small circuit of steam to force oil into a valve or cylinder through a choke. Black magic is a component of this process. Mechanical lubricators pump it in through a check valve, keeping the line under pressure as the check cracks open at a specific pressure. <p>Hydros are adjusted manually - counting drops of oil rising through a glass enclosed column of water. A needle valve varies flow. Mechanicals can be adjusted for output per stroke, but the number of strokes automatically varies with the speed of the locomotive, so once set, it is self regulating. <p>Feed points from mechanicals are sometimes run through small tubes into the center of the drypipes coming off the smokebox into the saddle. This lubricates the steam rather than the side of the pipe according to the fine print. <p>The process seems to work pretty well either way. Steam oils used to be composed with a component of animal fat ("tallowpot") to prevent water displacement, but I don't know just what new higher temperature oils use nowadays. <p>Whatever was in the exhaust escaped to the atmosphere. Also, steam is lubricated on the running gear in an open system whereby the oil runs off the valve gear and into the ground. Since oil comes from the ground, no sense getting too excited. The small quantities evaporate pretty well. <p>Dave<br>

 Post subject: Re: Lubricators
PostPosted: Mon May 25, 1998 10:39 am 

Steam oils come in two types. One for saturated steam and one for superheated. The two that are common within this industry are TK460 (for saturated) and Cylestic 1500 (superheated). The TK460 contains fats so it will cling to the wet cylinder. I am not sure what is in Cylestic. The steam oils are injected into the steam chest, delivery pipe, cylinders or valve chests. The oil is metered but does not self adjust according to demand. The point of injection is through a check valve so the steam pressure does not blow back through the oil delivery line. The delivery pressure is typically set at 25 Lbs over the boiler pressure. Some of this oil is exhausted into the atmosphere and does collect on the locomotive. Some may end up back into the feedwater if an open type heater is used. Generally this oil is collected in a trap so it does not end up back in the boiler. This could cause foaming. Foaming is for another thread, Bye.<br>

 Post subject: Re: Lubricators
PostPosted: Wed Jul 15, 1998 8:16 pm 

On Pere Marquette 1225, the mechanical oiling system operates at above 400 P.S.I., which is the pressure the check valves are set to open at. The 1225 operates at a steam pressure of 245 p.s.i. The key characteristic of superheated valve oil is that it must not burn at the temperature of the superheated steam, as conventional oil will. I don't know what's in it, either. Even with an oil trap, some of the valve oil on an engine with an open feedwater heater, such as the 1225's Worthington Type "S" will get into the feedwater. In addition to foaming, the oil turns into deposits that tend to clog the superheater elements with asphalt, causing burning-out of the units.<p>Aarne H. Frobom<br>Michigan State Trust for Railway Preservation, Inc.<br>

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