Sherwood Oasis

[fire_diver]

Thanks for the support of Sherwood SCUBA

See if you can answer this to my satisfaction....

My Oasis features the dry bleed function. I also have an Aqualung that is sealed. What is the benefit of having that constant stream of bubbles leaking from my 1st stage? Why do other regs NOT incorporate this feature? Are there down sides to the air bleeding? How do I know if it's bleeding 'enough' or too much?
Lastly, this bleed valve seems to be installed in a standard port. Is there any diving situations where a repair tech would simply plug that port?

FD

PS- I post this here rather than in a PM, as I feel others can benifit from the information also.

 

[ReefGuy]

The dry bleed function is designed to keep a constant hose pressure, which makes the reg a better breather at depth (even at extreme depths, the hose pressure will not fall below 140psi when you're taking a breath). The rate of bleed should be 13-27cc/min

 

[reeldive]

The dry bleed function is designed to keep a constant hose pressure, which makes the reg a better breather at depth (even at extreme depths, the hose pressure will not fall below 140psi when you're taking a breath). The rate of bleed should be 13-27cc/min

From the Sherwood web site

"Dry Spring Chamber and One-way Bleed Valve
Prevent contamination (sand, salt, silt, petroleum products) and excessive corrosion, improve reliability and help prevent freeze-ups. This means your Sherwood regulator is more reliable on a dive trip, and can help save on maintenance costs.
*All Sherwood regulators."

Internally you will find a flow filter betweem the HP chamber and the spring chamber, which allows a small amount of air to flow through the spring compartment and through the one way flow valve, keeping it about 3 psi above the ambient water pressure. The one way valve (ie. rubber stopper) is on the spring side of the piston and not in the intermidiate presure side of the piston thus keeping water and other debris out of this area. On most other regulators, the spring and one side of the diaphram is open to the water, and the rest of the environment. On regs that are intended for extreme low temp environments, this area is filled with oil and sealed with a second diaphram to prevent freeze ups.

It is imperative that you have your reg serviced by a TRAINED service tech!!!

 

[fire_diver]

From the Sherwood web site

"Dry Spring Chamber and One-way Bleed Valve
Prevent contamination (sand, salt, silt, petroleum products) and excessive corrosion, improve reliability and help prevent freeze-ups. This means your Sherwood regulator is more reliable on a dive trip, and can help save on maintenance costs.
*All Sherwood regulators."

Internally you will find a flow filter betweem the HP chamber and the spring chamber, which allows a small amount of air to flow through the spring compartment and through the one way flow valve, keeping it about 3 psi above the ambient water pressure. The one way valve (ie. rubber stopper) is on the spring side of the piston and not in the intermidiate presure side of the piston thus keeping water and other debris out of this area. On most other regulators, the spring and one side of the diaphram is open to the water, and the rest of the environment. On regs that are intended for extreme low temp environments, this area is filled with oil and sealed with a second diaphram to prevent freeze ups.

It is imperative that you have your reg serviced by a TRAINED service tech!!!

You seem to know the system quite well. But I'm still in the dark here. Why does a system that bleeds air prevent corrosion and contamination more than a system that is sealed?

Also, how does it prevent freezing in the 1st stage? I understand the principle of adiabatic (SP?) cooling resulting in freeze, but how does this bleed system change that?

finally, can the Oasis be modified by a tech to an oil system if I wanted to take it ice diving at some point?
FD

 

[reeldive]

Air around the spring doesn't freeze, Water does, ergo - no water no ice! The Oasis is not designed or intended to be modified to an oil filled sealed system. Because of this it is easier to service. and cheaper. All sealed systems require special overhaul kits for thier annual and are, by nature, more labor intensive. The oil has to be replaced. Trust me, I went through te Mares training on this.

For cold water environments Sherwood makes the Blizzard. The primary stage is designed to retain heat from your breath to combat freeze ups there.

Haveing said that - I'm not a cold water diver nor do I intend to be. If you anticepate ice diveing by all means ask for the advice of those that do.

Love my Oasis for warm water. I do a lot of 100' dives within recreational limits. Temps down to about 60 deg F. The moisture retention fins do a great job of preventing "dry mouth"

Should be a lot of people here that have experience with cold water

Good Luck and Have fun

 

[bogrady]

Hey Sherwood SCUBA Rep - welcome to the boards. After a long research effort, my newbie son and I settled on 2 Maximus regs. Just got them and love them. We've suffered through all the comments and upturned noses of the "high-end" reg crowd. One LDS shop owner even offered - "Well, when you get serious about diving, you could trade them in for real regulators ... I'll give you $150 bucks for them" (As an aside, the ScubaPro Octo he rented me that day blow off the end of the hose at 60 feet down. Learned a lot on that dive.)

Anyway - can you take this dry spring chamber discussion a bit further and clarify the difference between the Sherwood first stage (continuous bubble stream) and the Genesis first stage (which apparently only bubbles on the acent)? We got real close to Genesis GS2000's. The under arm setup of the Maximus pushed us to the Sherwood, but I never understood the difference between the two similar first stages.

 

[fire_diver]

Thanks for the replies. I don't have any current plans for ice diving, but I could see it as a possibilty sometime in the future. I have dove water in the 40's with my Oasis and never had a problem. And I don't think my mouth has ever felt dry during a dive, so the fins must be working!

FD

 

[Sherwood SCUBA rep.]

They are very simular in how the work, the big diffrence is the Genesis Firts stage maintains a "seal " of air .No water ,salt ,silt or sand enters your 1st stage (like the Sherwood ) Only the correct amount of air is added during descent to maintain equal pressure. During ascent the air in your 1st stage expands and the air is vented , thats the big diffrence.