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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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ScubaLawyer
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First Name: Mark
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Hope-Page question

Sat Jun 27, 2020 5:42 pm

So why is the exhaust side of a Hope-Page smaller in diameter than the inhalation side? I'm thinking maybe to prevent blow-by of the air and to direct more to the diver? Any ideas? The wagon wheels are identical.

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"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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luis
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Re: Hope-Page question

Sat Jun 27, 2020 9:46 pm

The flow areas in the wagon wheels of the Hope-Page are small, but they can accommodate a fairly large valve.

The inlet side of that body has to provide sufficient opening to accommodate the opening of the valves. It has to provide clearance so that it doesn't affect the valve opening motion.

But, the outlet side doesn’t care about the valve opening since the valve opens away from the center body. The outlet only needs to have the same flow area as the actual valve. It doesn't have to provide clearance for the actual valve.

I believe that both inlet and outlet valve wagon wheel ID are actually a bit smaller diameter than the opening you are showing, but they may be the exact same diameter. In either case, that opening would not affect the flow.



I am going to guess that they might have made the two sides different so that you cannot install the valves backwards, but that is just a guess.
Luis

Buceador con escafandra autónoma clásica.

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luis
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Re: Hope-Page question

Sun Jun 28, 2020 2:29 pm

Hi Mark,

Have you measured the ID of the wagon wheels, in comparison with the ID of the center body opening?
Luis

Buceador con escafandra autónoma clásica.

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ScubaLawyer
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Re: Hope-Page question

Sun Jun 28, 2020 2:47 pm

luis wrote:
Sun Jun 28, 2020 2:29 pm
Hi Mark,

Have you measured the ID of the wagon wheels, in comparison with the ID of the center body opening?
The ID of the wagon wheel and the ID of the exhalation side of the body are identical.

Something else I had never noticed with the Hope-Page. The wagon wheels are specific to inhalation and exhalation sides.

This can be seen in two ways.

First, there are small round mold marks on the wagon wheels; however, they are on different sides on the two wagon wheels (ridge and non-ridge) so that the valve can lay flat on a smooth surface (the opposite side of where the round mold marks are).

Second, the hole in the middle of the wagon wheel is  recessed on the mold-mark side of each. Again, to accommodate the valve itself laying flat on the opposite side.

Hope I'm making sense and that this isn't something everyone already knew. :) Bottom line is that using the correct wheel on the correct side with the correct orientation is important. My 2psi. Mark


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"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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