266 STANDARD LUBRICATING OIL SYSTEM FOR GEARED TURBINES. 



I would say that the condemnation of the pressure system, which has been made by a 

 good many people, is based on those systems which were not properly regulated, and which, 

 I think, do not come up to the standard requirements for a pressure S3'stem. 



There are several points in the paper which I wish to refer to. From its title it might 

 "be understood to refer to the single standard type of lubricating oil system. It is believed, 

 however, that other types than the one described in the paper are also good, or perhaps 

 better than the one which is described here. 



Another point is, that the object of standardizing, of course, is a good thing in certain 

 cases, but in this case it is believed that the degree of standardization was carried too far 

 and not enough latitude was allowed the designers to produce a good installation. In many 

 cases the provisions of these technical orders were such that they could not be carried out 

 at all. The layout of the ship did not pennit it. 



In connection with these technical orders, there is one point that might be brought out, 

 namely, a great deal of energy was spent in directing the designers how to build these lu- 

 bricating oil systems. As far as I have been able to find out, no instructions were provided 

 for the operating force in telling them how to operate the oil system. It seems more impor- 

 tant to have the operating force know how to run the oil system than it is to instruct the 

 designers to design them, because in most cases you have a fairly good man to design these 

 systems. That is referred to on page 244 of this paper. We prepared a very thorough set. 

 of instructions for the ships we turned out of the pressure type of lubricating oil systems, 

 furnished the instructions to the engineers, and had no trouble whatever with any of them. 

 On page 345 it states : "Nearly all the oil coolers previously used were inadequate to 

 transfer the required number of British thermal units, which amounted in a number of in- 

 stances to 10 per cent of the propelling turbine horse-power. This was partly due to the fact 

 that the reduction-gear manufacturers had overrated the efficiency of their reduction gears." 

 That is a matter of design, of course, and it does not apply to these oiling systems where 

 the coolers and other parts of them were properly proportioned and figured out. In this 

 connection, however, attention is called to the fact that if the lubricating oil cooler is de- 

 signed for a certain viscosity of oil — say 300 seconds at 100° F. — it will not take care of 

 oil of twice the viscosity and give the same result. The heat transfer is affected greatly 

 by the viscosity of the oil. In some ships the systems were designed for medium grade oils, 

 and then very heavy oils were put into them,. In such cases the oil systems could not be 

 expected to function properly. 



On page 345 it is stated that 10 per cent of the propelling horse-power is transmitted to 

 the oil. I hardly thinjc that is the case. At least I have never seen any tests or experi- 

 ments that would show that so much heat was transferred into the oil, and I would say, off- 

 hand, that about half of that would be the correct figure. 



On page 345 it is stated that the technical order specified a drop of 30 degrees in the oil 

 temperature. It is not possible for the designer to fix the temperature drop in the oil 

 cooler, for the reason that the flow of oil is determined by the design of the machinery. 

 There are so many holes of a certain size, and it takes just so much oil to go through it. 

 Then, again, the quantity of heat transferred to the oil is constant under constant speed con- 

 ditions. Therefore, with constant circulation and constant heat transfer, the temperature 

 drop in the oil regulates itself — the designer has no control over it. 



In our particular vessels the temperature drop in the oil was about IS degrees instead 

 of 30 degrees, due to the fact that there was a very heavy circulation of oil, amounting to 



