Check Valve on blower inlet?


 
D

DKellogg

TVWBB Member
So, i need something. Chargriller Smokin Pro with firebox door sealed with Permatex red. I tried the ping pong ball on the fan outlet but couldn't get hardly any flow past the ball with a 25 cfm blower at 100%. Have use a homemade cardboard flap on the fan inlet, which worked okay, but still got over shots.

I'm considering a different chamber for the ping pong ball (two Gatorade bottle top taped together), which would be easier to mount to the inlet. Here's my question.... is the there and difference if i put the ping pong ball on the inlet? I know with certain types of water pumps the pressure head is stronger than the suction head.... Anyone know if these types of blowers are similar?
 
The blower is supposed to go under the ping pong ball at the air inlet, even the 6.7CFM fan can blow the ping pong ball up to get air flowing. Did you cut the slots in the top cap of the valve body??? You need those slots to let the air flow around the ball, otherwise it will close off when the ball hits the top AND the bottom, you only want it to close off when the ball is at the bottom....
Maybe if you post some pics of what you've got going on with your ping pong valve I can help you out...

Edit: Here is a pic of the top portion of the valve with the slots cut in it to let the air flow around...
PingPongValveSlot.jpg


and an exploded view of my shortened valve design:
PingPongValveShortEXP.jpg


and a pic of it connected to my grill so you get the full picture of how it is implemented:
AkornDamper.jpg
 
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Ralph,

How big is your ball relative to the ID of the 1-1/2" PVC? Mine is only maybe 1/16" smaller than the pipe. Just not enough air could get around the ball to the slots.

Going to try the gatorade tops - hopefully it won't be too noisy with the ball bouncing around.
 
I've heard people say there are a couple slightly different size ping pong balls, so maybe that is what you've got going on... So maybe try some cheapo ping pong balls, believe it or not I see them in the isles of my local grocery stores and in the $1 "stuff" bins. I don't have the thing right here next to me right now so I can't give you answers on the sizes, but there is enough space around the ball in the tube to allow plenty of air to get through.
 
I'll try to hunt down smaller balls.

W/R/T my original question of the impact of the valve before (upstream) or after (downstream) of the blower, I spoke with an HVAC guy that indicated that is *shouldn't* matter. The blower raises the pressure regardless of what is up and downstream. I'll set up it before and if I have problems, will change to after.
 
Think of the lotto ball machine, air blowing up under the ball lifting it. I'm not sure if I am understanding your questions as to upstream vs downstream, but drawing air from above the ball seems like it would be more difficult to make the ball rise reliably, particularly at lower flow rates. I designed my valve to blow air up on the bottom of the ball and I know that configuration works well.

Speaking of flow rate... Once you have the valve worked out you should set the HM to manual mode and raise the blower speed slowly until you determine the slowest speed required to raise the ball reliably, then set your MIN blower speed to that %.
 
Some types of pumps work better pushing (blowing) than pulling (lifting). In my proposed layout, i will be pulling the ball. Because we use centrifugal blowers (squirrel cages), there shouldn't be a negative effect of pulling vs. pushing. Time, and trials, will tell.

Already played with ball weight (salt) vs. pushing the ball. Hopefuply pulling it won't change that.
 
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