History of Balanced Regulators?

[ginti]

Maybe @Angelo Farina knows something; I am not sure if this is also a field @David Wilson knows well.

 

[David Wilson]

Maybe @Angelo Farina knows something; I am not sure if this is also a field @David Wilson knows well.

Thanks for thinking of me, @ginti, but regulators both balanced and unbalanced remain strictly outside my sphere of interest, research and experience. Aquatic apparel and basic gear such as fins, masks and snorkels represent the limits of my comfort zone when exploring diving equipment history.

 

[James79]

I don't understand how the drawing in the patent could be a balanced second stage. There is no balance chamber or other apparent way to counteract changes in inlet pressure.

The poppet stem passes outside the valve body into the can, and is the same diameter as the orifice... Effectively using the entire regulator can as a balance chamber.
Respectfully,

James

 

[lowwall]

The poppet stem passes outside the valve body into the can, and is the same diameter as the orifice... Effectively using the entire regulator can as a balance chamber.
Respectfully,

James

But that only balances the low pressure section. A balanced regulator is one that performs the same regardless of changes in the incoming high pressure. In practice, this means that the high pressure needs to be applied to both ends of the valve body, leaving the spring (and any friction) as the only force to be overcome.

In this regulator, if the incoming pressure is higher, the force needed to open the valve will be higher. It's easy to visualize if this is a first stage valve. Imagine inlet 4 is hooked up to an LP72. When the cylinder is full, you'll have 2250 psi ushing on the back of the guiding head 8. As the tank pressure drops, the force drops making it easier to operate the valve.

I think I see my problem. I've been assuming the guiding head 8 seals off the HP section. But if the gas is free to pass around 8 then there would be no net force from the HP gas on the rod. With the LP forces balanced, the whole thing would be balanced. Clever.

 

[John C. Ratliff]

I presented this not as a fully balanced regulator, but rather as an interesting design from the late 1950s, which was presented as being balanced. The actual patent drawing is not what was actually produced too. But the concept of "balanced" is and has been changing over the decades. If you go to the VSS link, you can see some further discussion of this design.

La Spirotechnique Narghile or Narguile Hookah Regulators | Vintage Scuba Diving Community Forum

I got 3 Narghile hookah regulators a while back. I bought them from a seller in Turkey, who wanted way more than I paid, but even so, I got screwed big time. It wasn't his fault entirely, although he

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SeaRat

 

[Luis H]

Is there such a thing as a pressure reducing regulator that is not compensated? Even dome loaded regulators are designed to be compensated. I suppose you could plug the dome at a given pressure to make it compensated to a fixed pressure (depth).

Yes, but they are only used on some rebreathers.

Since we metabolize the same amount of O2 at any depth, the amount of oxygen that needs to be replenish is not a function of depth.

I believe they are more common on semiclosed rebreathers and maybe some semi-manually controlled units, but I don't know for sure.

I only have a limited working knowledge of the science behind rebreathers, so I can't comment much further.

 

[Luis H]

But that only balances the low pressure section. A balanced regulator is one that performs the same regardless of changes in the incoming high pressure. In practice, this means that the high pressure needs to be applied to both ends of the valve body, leaving the spring (and any friction) as the only force to be overcome.

In this regulator, if the incoming pressure is higher, the force needed to open the valve will be higher. It's easy to visualize if this is a first stage valve. Imagine inlet 4 is hooked up to an LP72. When the cylinder is full, you'll have 2250 psi ushing on the back of the guiding head 8. As the tank pressure drops, the force drops making it easier to operate the valve.

I think I see my problem. I've been assuming the guiding head 8 seals off the HP section. But if the gas is free to pass around 8 then there would be no net force from the HP gas on the rod. With the LP forces balanced, the whole thing would be balanced. Clever.

Yes, that is a balanced valve design and (at least in theory) the force that the diaphragm has to apply to open the valve should be independent of the pressure source. It is pneumatically a similar design to the single stage US Divers Royal Mistral.

In theory the air pressure source could be anything from high pressure to some minimum pressure above ambient (the low end may not be good).

The valve seal in the Royal Mistral was very unreliable and a total failure, but that was due to a bad design details, not the concept.


I have used the valve components from a balanced diaphragm first stage (the typical Conshelf first stage) and modified it to make a balanced single stage regulator. It works extremely well at any tank pressure and any depth that I would care to take it.

I have measured the actuating force to open the valve with tank pressure change every 100 psi (from full to empty) and it is as constant as I expected.