December 25, 1921 



HARDWOOD RECORD 



.^1 



YARD AND KILN 



(lA Section Intended to Promote Efficiency^ 

 and Economy in Lumber Drying ^ 



Questions and Their Answers 



From time to time we receive inquiries from our readers who have- 

 problems to solve pertaining to the yard or to their kilns, of which 

 those herein printed are a fair sample. In the past we have generdlly 

 answered direct, iy mail, those questions with the solution of lohich 

 we were familiar, and have referred to some of our expert friends, 

 those which required special information. 



We will henceforth print as many of such inquiries, and the proper 

 solution of the problems which they represent, as will prove of general 

 interest, and in this we hope to arouse discussions of the more impor- 

 tant subjects, thereby serving a greater nvmiber of our readers. 



We invite the sending of questions to this department. 



Question 3 — ^Vacuum Return System for Heater Coils 

 . Our engineer always tells me that if we had a ' ' Vacuum System ' ' 

 on our steam pipes in the kilns I would be able to keep my kiln 

 temperatures absolutely uniform without cussing his end of the 

 game, but I have never yet been able to get him to explain to me 

 just what such a "Vacuum System" is and how it works, and why 

 it would be better than our old steam traps are, if the engineer is 

 not too lazy to keep them in order. Will you please tell me all 

 about it so that I shall learn something, if the engineer is right, or 

 shut him up, if he is wrong? Tom. 



Answer to Question 3 



Your friend, the engineer, is right in boosting the Vacuum System. 

 It is very desirable, but such a system alone would not necessarily 

 enable you to maintain uniform kiln temperatures. A few other 

 things must be "right" in the combination. We had better explain 

 in full: < 



Your steam coils probably are of the "Header" type and are 

 operating on the "Gravity" system, that is, the steam is supplied 

 to the high end of each coil and in giving up its heat condenses to 

 water, which flows down through the heater pipes to the return 

 header, which is much lower than the supply header. From this 

 return header the "condensate" as it is called, flows to the steam 

 trap, into which a number of such heater eoils may be discharging 

 at the same time. To prevent interference, by steam backing up 

 into the several coils from any other coil, check valves are placed 

 at the outlet of each, between the coil and the steam trap. This 

 steam trap is so arranged that it will pass the water readily, but 

 will close tight when steam strikes it. If it were not for this action 

 of the trap, the steam would rush through the heater coils and out 

 into the return line, eventually finding its way to the atmosphere, 

 but before doing so, it would equalize the pressure between the 

 return line and the supply, thus interfering with the free discharge 

 of the condensation or condensate coming from the heater coils. 



But even if you have a good trap, in good order, you may find difii- 

 eulty in discharging the water from same, if any point in the 

 ■discharge pipe which carries the water from this trap, or several 

 of them, back to the boiler plant or other point of its final disposal, 

 should be higher than is well within the lifting power of the steam 

 pressure at the trap, which latter should always be located at least 

 12" lower than the low ends of the heater coils. For instance, if 

 the steam pressure coming to your coils were 4 pounds on the gauge, 

 then the pressure at the trap may be only about 3 pounds, in which 

 ease this pressure could discharge the water driven by it from the 

 trap, only to a height of about 6', and no higher, and if the pipe 

 were raised higher at anj' point, the water would back up in the 

 heating system and refuse to flow out, unless the steam pressure 

 ■were raised. 



Now if, for instance, your friend, the engineer, were to furnish 

 you with steam of irregular pressure, this latter could easily drop 

 below the minimum necessary to free your coils of the condensate, 

 and consequently the kiln temperatures would drop, until the steam 

 pressure is restored to the point where it may overcome the weight 

 of the water and force it out of the system. This is one of the 

 conditions which the Vacuum system remedies definitely. 



There is another condition which frequently and seriously inter- 

 feres with the continuity of the removal of the condensate from the 

 heater coils and the return connections, and that is the air in these 

 pipes. Whenever a heater coil is shut off for a time, short or long, 

 it condenses the steam which fills it, forming a vacuum, and this in 

 turn draws the coil full of air. When steam is again turned into 

 this coil it must first expel this air before it can become fully active 

 on the full length of the coil. 



Being heavier than the steam, this air will be gradually pushed 

 toward the lower end of the heater coils, into the return headers, 

 into the pipe connections between these headers and the trap itself. 

 Now, since the steam trap cannot pass this air, it would remain 

 locked in the system, compressed to the same pressure as that of 

 the steam, and it would cause disturbance in two directions. It 

 would prevent the steam from acting fully on the entire heating 

 surface of the coil, especially at its lower end, thus lowering the 

 temperature in that part of the kiln, or it might completely prevent 

 the passage of the condensation from the heater to the trap through 

 the air-locked pipes, or if not entirely so, it would make the dis- 

 charges intermittent, all to the detriment of the drying lumber. 



Inter-Association Arbitration Idea Advances 



(Coiitiinicd jriim page 2S) 

 of a plan of procedure to be followed in inter-association arbitration 

 cases. This plan was based on that adopted by the American Whole- 

 sale Lumber Association. He reported that his committee had 

 spent several months in making an exhaustive study of the subject 

 in connection with which it had ascertained the views of many 

 practical lumbermen and secured the advice of several eminent 

 authorities on arbitration outside the lumber industry. 



Considerable discussion of the plan followed, with the result that 

 it was recommended that each association adopt the following 

 provision as a part of its By-Laws, Sales Code or Code of Ethics, 

 with such slight modifications as may be found desirable: 



In case of a dispute between a member of this association and a mem- 

 lier of any other association, arising out of a business transaction involv- 

 ing lumber or other forest products, and upon notice in writing to the 

 secretary of this association that arbitration is desired, this association 

 shall, with the approval of its member, express its willingness to submit 

 such differences to a joint arbitration committee consisting of two per- 

 sons, one to be appointed by each association, and in the event of the 

 failure of these two to agree tliey shall call in a third party. The joint 

 arbitration committee thus selected shall establish its own rules of pro- 

 cedure. The decision and award of a majority of the committee shall, in 

 all matters before it, be final and binding. 



Whenever, by notice in writing to the secretary of this association, 

 application is made for arbitration, either by, or on behalf of a member of 

 this association or by a non-member, who is a member of another asso- 

 ciation, or through the secretary of any co-operating association, the 

 secretary of this association shall forthwith use his best efforts to reach 

 an agreement between the parties to submit the dispute to arbitration. 

 This association shall, with the approval and consent of its member, 

 appoint the arbitrator hereinbefore mentioned. 



This recommendation includes the provision that the Arbitration 

 Committee in rendering their decision be requested so far as possible 

 to comply with the following suggestions: 



(a) Set forth clearly and in as much detail as may seem essential, all 



