Greenhouse inflation questions

tree bender

What do you use to inflate and how do you control over inflation? I'm using a Dayton 4C440 Blower that's directly connected to the poly. It seems to get the poly really tight. I turned it off for now until I can figure out how to control it. Are there such things as relief valves for greenhouse inflation?
thanks

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

Advertisement

tree bender

I also read that it's better to pull outside air into the poly. Does anybody have any experience with this?

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

tachigi

I myself have a double walled polycarbonate greenhouse. However, my neighbor a orchid grower of some repute has a double walled poly greenhouse. After reading your post I took a stroll down to his place and looked at his covering setup.

As far as venting goes. He on either side of the greenhouse has two spots that he has reinforced with polypatch and polyethelyne tape and made a very small (and I do mean small) incision as a relief. I put my hand over it and could just make out the slightest air movement coming from it. It should be noted that the relief was on the inside of the greenhouse.

As far as pulling outside air. He doesn't, he pulls inside air as he claims it helps with the insulating effect and aids ever so slightly in air movement.

It should be noted that his greenhouse's appear to be about half the size of yours. Which I would think would make a difference in your approach. Common sense would tell me with a surface area as large as yours that you would get some relief from the blower as there is probably some natural leakage in a surface area as big as yours.

__________________
Tom

Shady Side Bonsai
Bonsai Vault
4MAAT

tree bender

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

tree bender

Here's what I read on using outside air. Looks like I need to check out a Rheostat and Manometer.

Improper maintenance of the air pressure between the layers of double poly covered greenhouses can be responsible for premature wearing of the

film and shortened life expectancy. Here are some tips for keeping your poly inflated properly.

1. Control the pressure using the rheostat (variable speed control) that the inflation fan would be plugged into. Slowing down the speed of the

fan inflates to a lower pressure while speeding up the fan inflates to a higher pressure. Monitor the pressure with an inexpensive manometer.

2. Use outside air to inflate the poly. Outside air is usually drier and does not contain pesticides or other volatile chemicals that can interact with the poly.

3. Change inflation pressure according to the weather. Optimal inflation pressure is 0.2" of water column pressure during hot weather and 0.45" of water column pressure during cold and/or windy weather.

4. Avoid stressing the poly. If overinflated, the poly stretches and becomes thinner, making it weaker. If underinflated, the poly flaps and wears prematurely.

5. Maintain the installation as air tight as possible. Check poly locks occasionally to find and repair air leaks that lead to underinflation.

http://www.griffins.com/pdf/catalog...pages/33-48.pdf

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

Brent

I read #2 all the time, but most setups I see use inside air simply because its easier since the inflation fan is on the inside. That's what I do. Most inflation fans are of the squirrel cage type (rotating vaned drum) and the air is introduced from a hole around the axle. Mine has a simple plate that can be slid to partly cover the hole to regulate the inflow. I don't bother measuring the pressure, but keep the opening wide enough to to just keep the plastic 'taut' so it doesn't flap. This is much simpler and less expensive than a rheostat or fan controller. Most inflation fans made for this job have this cover plate.

Brent
EvergreenGardenworks.com
see our blog at http://BonsaiNurseryman.typepad.com

tree bender

Thanks for the tip Brent. I just read that some fans have an air intake adjustment. Of course the fan that came with the GH I bought isn't made for GH inflation. So I'll have to engineer my own.

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

tree bender

Wouldn't it put a strain on the fan if you blocked the air intake just a little? These things run 24/7 as it is. All I need is it to burn my greenhouse down..

__________________
Holding pasts in ash black earth
Bound by roots
Roots into sand
Grow towards the giver

Brent

No, there is no extra load at all, the fan just cavitates.

Brent