Are HOG D1 1st stages upstream or downstream?

[WhiteSands]

I.e. upstream reg fails closed (no air), and downstream reg fails open (free flows).

Does anyone know which kind the HOG D1 1st stages are? Thanks.

 

[dmainou]

They are apex clones. Almost sure they are downstream like most other regs.

Sent from my GT-I9300 using Tapatalk

 

[52brandon]

I'm 99.9% sure they're downstream

 

[redacted]

I.e. upstream reg fails closed (no air), and downstream reg fails open (free flows).

Does anyone know which kind the HOG D1 1st stages are? Thanks.

Where are you going with this idea? Your basic premise is mostly correct BUT: any regulator can fail in a way that it will not deliver any gas, depending on the part that fails.

 

[victorzamora]

As awap said, any reg can fail in a way that will not deliver gas.....but as far as upstream vs downstream, aren't those terms for the second stage? I don't know if a first stage CAN be "upstream" or "downstream." Their second stages ARE downstream regs.

 

[52brandon]

As awap said, any reg can fail in a way that will not deliver gas.....but as far as upstream vs downstream, aren't those terms for the second stage? I don't know if a first stage CAN be "upstream" or "downstream." Their second stages ARE downstream regs.

I thought it was the 1st stage that upon failure would continually send air to the 2nd if downstream or not send it at all if upstream. That's why it still breathes and purges when you're not breathing. The 2nd still works fine, but the 1st failed

 

[victorzamora]

If the first stage fails and sends hp had to the second stage, a downstream reg will free flow. An upstream reg will lose gas out of the OPV. If not equipped with an OPV, the hose would explode.

Sent from my Samsung Galaxy S4 using Tapatalk

 

[52brandon]

If the first stage fails and sends hp had to the second stage, a downstream reg will free flow. An upstream reg will lose gas out of the OPV. If not equipped with an OPV, the hose would explode.

Sent from my Samsung Galaxy S4 using Tapatalk

interesting. Thanks for clarifying. I had read previously that it was the 1st stage that failed up or downstream

 

[ams511]

Most regulators are of a down-stream design, the only ones that I know of that are up-stream are certain Poseidon models and their re-branded brothers. The HOGS are definitely down-stream.

 

[halocline]

As awap said, any reg can fail in a way that will not deliver gas.....but as far as upstream vs downstream, aren't those terms for the second stage? I don't know if a first stage CAN be "upstream" or "downstream." Their second stages ARE downstream regs.

This is pretty close to the way I would describe it. First stages are all 'regulating' valves. There's a big heavy spring that keeps the valve open, allowing HP air to flow through. As pressure builds up in the chamber beyond the valve, that pressure pushes against the big heavy spring to close the valve and stop any further pressure build up. This pressure is IP and is sent to the 2nd stages. Whenever you take a breath, it lowers the pressure in the IP chamber, which allows the spring to slightly open the HP valve and let some air in from the tank, until IP is restored.

So the force stopping air flow in all 1st stages comes from beyond the valve itself. This makes it extremely difficult for the first stage to 'fail' in a way that stops air flow completely. About the only way for that to happen would be a complete blockage of air in the HP chamber, most likely from severe contamination clogging the filter. But, that stupid little ball (AKA auto close device) that some manufacturers choose to put right in front of the filter could get stuck and block air as well. I'm SURE this occurred to the designers of this device and they've taken steps to prevent it from happening. I still wouldn't buy one.

The overwhelming majority of 1st stage 'failures' are related to leaks; either an o-ring starts to let air out or the seat in the HP valve starts to leak, allowing high pressure air to get sent to the 2nd stage.

Diaphragm 1st stages do have some upstream force on the valve, but this is not nearly enough to actually close it. It affects IP over the range of tank pressure but is typically balanced by keeping HP air out of a small chamber that contains the seat stem.