Tractor Exhaust Shop Evac System

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Has anyone built their own exhaust evacuation system for their shop? I'm thinking of doing so with an overhead boom and exhaust fan. The intake will attached over the exhaust pipe so little to no shop air is involved. Wondering if my thinking is correct? 

Seems to me the fan doesn't do much when the engine is running but rather performs its duties as the engine is running only when there is sufficient head wind to overcome the output of the tractor and, after engine shutdown to evacuate the system. 

Also, is my calculation correct for needed fan CFM capacity? I'm thinking a 262 CI engine at 500 rpm puts out 131,000 CI/minute. One CFM equals 1728 CI so a person would need a fan output exceeding 76 CFM. Is this correct? I think many of the small system fans are 300 CFM. 

TIA for any feedback!

	This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
	The Forum	Parts and Services	Unofficial Allis Store	Tractor Shows	Serial Numbers	History

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
KenBWisc Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 15 Sep 2009 Location: Fall Creek, WI Points: 1184	Post Options Post Reply Quote KenBWisc Report Post Thanks(0) Quote Reply Topic: Tractor Exhaust Shop Evac System Posted: 07 Jan 2012 at 9:38am
	Has anyone built their own exhaust evacuation system for their shop? I'm thinking of doing so with an overhead boom and exhaust fan. The intake will attached over the exhaust pipe so little to no shop air is involved. Wondering if my thinking is correct? Seems to me the fan doesn't do much when the engine is running but rather performs its duties as the engine is running only when there is sufficient head wind to overcome the output of the tractor and, after engine shutdown to evacuate the system. Also, is my calculation correct for needed fan CFM capacity? I'm thinking a 262 CI engine at 500 rpm puts out 131,000 CI/minute. One CFM equals 1728 CI so a person would need a fan output exceeding 76 CFM. Is this correct? I think many of the small system fans are 300 CFM. TIA for any feedback!
	'34 WC #629, '49 G, '49 B, '49 WD, '62 D-19, '38 All Crop 60 and still hunting!

Sponsored Links

Orange Blood Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 29 Nov 2010 Location: ColoradoSprings Points: 4053	Post Options Post Reply Quote Orange Blood Report Post Thanks(0) Quote Reply Posted: 07 Jan 2012 at 11:02am
	You will want the fan to do something if you are going out a sidewall or roof. There needs to be negative pressure in the line for it to do anything worth a hoot. If you rely on the tractor exhaust to force the exhaust out the line, any and every leak will be evident, and the back pressure could cause problems when trying to tune your tractor. I know you don't want much shop air involved, but most of these systems in the large shops run anywhere from 1000-2500 cfm, depending on how many "stations" there are, and the seal at the exhaust stack is purposely left loose be an inch or so, so that all of the exhaust fumes are evacuated. As far as the math, I think you are double what you need, a 4stroke engine only fires and expels once every two revolutions, so you are actually only putting 131 Cubic inches of displacement through the engine in any one revolution. Which gives you 65500 per minute at 500 rpm or only 37 cfm per minute, all of this leaves out thermal expansion of the hot gasses, and so on. But if all you are ever going to do is idle your light 4 or 6 cylinder tractors in the shop, put in a 500cfm fan since all the tubing and duct work will cut down on efficiency, and you should be good. Edited by Orange Blood - 07 Jan 2012 at 11:02am
	Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7

Stan R Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 03 Dec 2009 Location: MA Points: 992	Post Options Post Reply Quote Stan R Report Post Thanks(0) Quote Reply Posted: 07 Jan 2012 at 12:59pm
	And maybe a carbon monoxide detector in the local area?

DonBC Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Location: Courtenay, BC, Points: 944	Post Options Post Reply Quote DonBC Report Post Thanks(0) Quote Reply Posted: 07 Jan 2012 at 1:40pm
	Just as important as volume is static pressure that the fan can deliver. The static pressure required will depend on duct size, length, number of obstructions such as elbows in the system. You could send me details on pipe size and length and I could come up with a specification or just take a chance with a 500 cfm fan capable of at least 1/2" static pressure.
	Jack of all trades, master of none

stray Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 16 Aug 2011 Location: Tipton, Missour Points: 323	Post Options Post Reply Quote stray Report Post Thanks(0) Quote Reply Posted: 07 Jan 2012 at 2:23pm
	Watch what you use for hose also. At work when they built the new shop we didn't know to spec. a special temp hoses. So the contractor install the cheapest (low bid you know) and it was about a year and they where coming apart (of course after the warrenty ran out). When I called the manufacture they said that those weren't to be used with desiel engines do to the heat of the exhuast.
	1969 190XT series 3

Brian Jasper co. Ia Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 11 Sep 2009 Location: Prairie City Ia Points: 10508	Post Options Post Reply Quote Brian Jasper co. Ia Report Post Thanks(0) Quote Reply Posted: 07 Jan 2012 at 6:39pm
	If at all possible, put the fan outside. The noise is more annoying than you think.
	"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford

MBWisc Members Profile Send Private Message Find Members Posts Add to Buddy List Silver Level Joined: 13 Apr 2011 Points: 103	Post Options Post Reply Quote MBWisc Report Post Thanks(0) Quote Reply Posted: 08 Jan 2012 at 8:46am
	Thanks much! (Using my wife's handle now). I am familiar with ventilation design, static pressure,etc.

DaveKamp Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Apr 2010 Location: LeClaire, Ia Points: 6069	Post Options Post Reply Quote DaveKamp Report Post Thanks(0) Quote Reply Posted: 08 Jan 2012 at 9:23am
	Ken... you can estimate CFM based on the engine's speed and displacement, and he's right about it only firing half as many times per rotation, but the actual volume of the exhaust is much larger than engine displacement... the exhaust gasses exit under pressure, and as they exit, they expand many times over. I think what I'd do, is multiply the required volume by about five, and then use static pressure as the indication. You WILL involve turnover of shop air- there's no way around it, but if it's heat you're worried about losing, realize that there'll be quite a bit of heat radiated by the tubing (carrying the exhaust gasses out) and the waste heat of the running engine making up for what's lost out the stack. If you wanted to be sophisticated about it, what you COULD do, is use a 3-phase motor on the blower, put a manometer on the evactuation blower's inlet tube, and tie that to the speed control input of a variable-frequency drive. What would happen, is that the blower motor's speed would be controlled by the vacuum present at the blower... when the vacuum is too low, the manometer's output would signal the VFD to drive the motor faster, and vise-versa... Then, all you do, is program the VFD so that the 'offset' is the amount of in/hg that you want to pull under all conditions. As the engine throttles up, manometer pressure falls, and the VFD increases blower speed to suit...