What's new

Negative pressure reading

FTL

Well-known member
No scrubber?
I have never found a scrubber good enough to recirc, like the two fan system outlined. I have double filtered with an ozone gen following, but it's just not enough. I have been through the makes, and had carbon by the pallet to get importers to send the lorry. Giving me access to a world of grades, from the two biggest names in the business. I have 100% exhausted the choices. They are very useful, but just as the moisture passes through them, so does anything dissolved in that moisture. They have defined limits. The difference in effectiveness starts to come down to who it is that's smelling it.

I can do something similar. The lung room can't use a stat, it would run all the time to ensure negative pressure on the whole space. It would be the tent extract with the temp/rh control. Both systems would need a filter, as I need to open the tent and trim/dry in the room.
This need to keep the lung under negative pressure, doesn't reduce cold through the property. It's an improvement on what I have, but still leaves me looking at the actual pressure and fan control to achieve it. One ideal, is a fan speed controler on that lung extract, that's not interested in temp or RH, but modifying the pressure. Set low, it's for normal. Set high, for trimming days. However, its the pressure I'm turning up and down.

If this can be made simple, and works, then people will realise it's useful.

I have other ideas, with duct divertor valves. When a set extract fan, moves duty between tent and lung, incrementally as needed. I really need to free up £50 for a mess about, but this month is my taxes, my cars shot, and my phone's well overdue replacement. The boiler need tending to regularly, just to run on low, and child support for 2025 is due.
I might have to take the tent out, and get commercial about this. Them divertors are not the right thing though, as they just aint cheap. Louvers over passive filter on the lung intake are also too expensive. I need to focus on fan speed, not actuators.
Lose the tent mate, they make life harder than it should be imo.

You could then try having one filter/fan on 24/7 at full speed as an outtake from the room.

Use passive intake to bring in fresh air.

Add a small intake fan on thermostat to increase flow/cool when needed. Make sure that negative pressure is still maintained mind.

K I S S
 

Absorber

Well-known member
This may be the droid I'm looking for
https://www.ali express.com/item/1005004668884481.html

It's like the one pictured before, except alloy, with a digital readout, and instead of a switch, it's 0-10v output. Just like an EC fan. £30 delivered.
No pressure difference, no inlet fan. More difference, more fan. All that's left is a little scaling.
This also suits my room inlet air scrubber. I would like to provide clean air. I can't supply more than the exhaust takes, or I go into positive pressure. Or jail. If Instead I supply less, the exhaust must work harder, and will find other gaps to bring air in from. Dirty air. With atmospheric pressure monitoring, I can have real time inlet air adjustments. Ones that track exhaust speed, and the opening and closing of doors.

I might pop it on the back burner for now, but it's interesting. I have also been looking at linear actuators for louver grills, so my exhaust fan still does all the work, but I make it's job easy (and quiet) as possible.
I 3d printed inline shutters , i run 1 big 250mm silenced extraction fan that has a 3d printed Y piece and two 100mm inline shutters one for each tent so if one tent calls for exhausting the fan turns on half speed as that shutter for the tent opens and if the second tent calls for extraction aswell the second tent shutter opens and fan ramps up to full speed .
You could probably use the same shutter design in your application
20250116_150638.jpg
 

FTL

Well-known member
I 3d printed inline shutters , i run 1 big 250mm silenced extraction fan that has a 3d printed Y piece and two 100mm inline shutters one for each tent so if one tent calls for exhausting the fan turns on half speed as that shutter for the tent opens and if the second tent calls for extraction aswell the second tent shutter opens and fan ramps up to full speed .
You could probably use the same shutter design in your application View attachment 19133251
That’s really cool.
Could you post up the schematic or link to the design?
 

FTL

Well-known member
@FTL make sense ? If you have a 3d printer i can send a link for the STL files
Yeah mate :)

Cheers for that

I don’t have a 3D printer .... or a grow room atm :ROFLMAO:

But I thought it would be cool for people to see in the future when reading this thread to give them options/solutions to their problems :)
 

Absorber

Well-known member
Yeah mate :)

Cheers for that

I don’t have a 3D printer .... or a grow room atm :ROFLMAO:

But I thought it would be cool for people to see in the future when reading this thread to give them options/solutions to their problems :)
Could also be good for those running Co2 to keep tent sealed when fan isnt on
 

Ca++

Well-known member
What's the shutter look like physically? An iris would be cool, but difficult. A cat flap a lot easier. I was looking at gravity grills for there availability, and some form of linear actuator. With a printer, the flaps could be done again, but even wires like vertical blinds use, could work in the right orientation.

Edit: Butterfly?
 

Ca++

Well-known member
Lose the tent mate, they make life harder than it should be imo.

You could then try having one filter/fan on 24/7 at full speed as an outtake from the room.

Use passive intake to bring in fresh air.

Add a small intake fan on thermostat to increase flow/cool when needed. Make sure that negative pressure is still maintained mind.

K I S S
TBH, I have never liked tents. I adopted early, and got a serious yield drop, I have spent many many years recovering from. Now with LED, I have got back where I was, but feel that's no advance for years of experience and equipment changes.
 
Last edited:
  • Like
Reactions: FTL

FTL

Well-known member
TBH, I have never liked tents. I adopted early, and get a serious yield drop, I have spent many many years recovering from. Now with LED, I have got back where I was, but feel that's no advance for years of experience and equipment changes.
The hydro intdustry loves solving problems with solutions that create more problems to which they of course have more products as solutions.

Could be time to put the tent away, dust off the hps and do awinter hps/led double up run ;)
 

Absorber

Well-known member
What's the shutter look like physically? An iris would be cool, but difficult. A cat flap a lot easier. I was looking at gravity grills for there availability, and some form of linear actuator. With a printer, the flaps could be done again, but even wires like vertical blinds use, could work in the right orientation.

Edit: Butterfly?
Yea butterfly ,a round disc that spins 90°
 

Ca++

Well-known member
I will have to circle back to this. Ali has butterfly air valves with actuator, in most sizes, for between 15 and 25 shiny coins delivered. The actuator (12 or mains) will only motor to it's end stops, with no proportional use. However, at such prices, each zone could have a direct pipe for trickle, and a couple of bypass valves in parallel. It's not a huge mess, or price. A manual one is just a few coins, for seasonal trim of the airflow. It's probably overkill using two motorised per zone tbh.
Are you doing anything propertional, or just setting a trickle and opening up to full?
 

Absorber

Well-known member
I will have to circle back to this. Ali has butterfly air valves with actuator, in most sizes, for between 15 and 25 shiny coins delivered. The actuator (12 or mains) will only motor to it's end stops, with no proportional use. However, at such prices, each zone could have a direct pipe for trickle, and a couple of bypass valves in parallel. It's not a huge mess, or price. A manual one is just a few coins, for seasonal trim of the airflow. It's probably overkill using two motorised per zone tbh.
Are you doing anything propertional, or just setting a trickle and opening up to full?
Shutter opens fully and fan only runs at half speed while one tent is calling for it , theres no inbetween its 50% or 100% fan if second tent calls for it aswell .
 

Ca++

Well-known member
Hfd2e3011a2dc47648504090cc42bde44E.jpg


The 75mm one, is £9/$11usd delivered. Most of that price is the motor.
Like with a car throttle body, the butterfly opens for full flow. When it's closed, there is a bypass pipe for tickover.

Example: I could run two pipes between fan and filter, with this in just one. In the other, the £3 dumb version, set manually. The dumb version does about 80% of the extract. So you always have extract. The £9 one is the regulation, that switches on/off.


Can we really print one cheaper, with a motor. These particular motors are £7 and have the stop switches internally. The middle wire is N and you move L between the outer ones, with a changeover relay perhaps.

I'm selling this to myself. I really don't need bigger than the 75mm one, but the 100mm is about £14/$18. The increase is a lot, because it's postal volume increases. The cost of T-pieces and such get painful, and printing them would be tidy. The T with the parallel legs is particularly nice, for splitting then rejoining pipes, for parallel valves.

I can see this in my future, as the threat of a smart electric meter, means I have to do two flower areas to avoid 12/12 power usage patterns.
 

Absorber

Well-known member
Hfd2e3011a2dc47648504090cc42bde44E.jpg


The 75mm one, is £9/$11usd delivered. Most of that price is the motor.
Like with a car throttle body, the butterfly opens for full flow. When it's closed, there is a bypass pipe for tickover.

Example: I could run two pipes between fan and filter, with this in just one. In the other, the £3 dumb version, set manually. The dumb version does about 80% of the extract. So you always have extract. The £9 one is the regulation, that switches on/off.


Can we really print one cheaper, with a motor. These particular motors are £7 and have the stop switches internally. The middle wire is N and you move L between the outer ones, with a changeover relay perhaps.

I'm selling this to myself. I really don't need bigger than the 75mm one, but the 100mm is about £14/$18. The increase is a lot, because it's postal volume increases. The cost of T-pieces and such get painful, and printing them would be tidy. The T with the parallel legs is particularly nice, for splitting then rejoining pipes, for parallel valves.

I can see this in my future, as the threat of a smart electric meter, means I have to do two flower areas to avoid 12/12 power usage patterns.
I got 4 of the motors i use for $24 and can probably print 3-4 shutters with a roll of ABS filament for $25 .
 

Absorber

Well-known member
Example: I could run two pipes between fan and filter, with this in just one. In the other, the £3 dumb version, set manually. The dumb version does about 80% of the extract. So you always have extract. The £9 one is the regulation, that switches on/off.
I cant see why you couldnt use a stepper motor and then you could write some code to move stepper in increments you could have closed , partially open and fully open . Therefore removing the need for parallel pipes
 
Top