Strange Hose

[ams511]

I am going through my spares deciding what to ebay. I found a brand new low pressure hose about 22" that is thicker than a normal hose. It fits a standard second stage fine but will not screw into a standard LP port on a first stage. It has a black cap on the end while the thinner hoses have red caps. Anyone know what this hose is used for?

 

[onfloat]

Might be for an Apex DST. It has one LP port that is larger than the standard LP port.

 

[TN Traveler]

It could also be from a Mares regulator - they use a 1/2" hose connection for the DFC port (for the primary second stage).

 

[ams511]

I don't have a true Apeks first but I did look at my rebranded Beuchat and Zeagle. The Zeagle first has normal ports while the Beuchat first does appear to use a thicker hose on one of the first stage ports. I will check it out maybe I can use the hose after all but I will need to check the routing.

 

[paulwlee]

It's a 1/2" LP port, as opposed to the standard 3/8" LP port.
Aqualung and a few other companies experimented with the larger diameter port and hose (although some had the larger port but normal hoses ) for better performance on the primary second stage. These are mostly going away now.

 

[Lone Frogman]

It's a 1/2" LP port, as opposed to the standard 3/8" LP port.
Aqualung and a few other companies experimented with the larger diameter port and hose (although some had the larger port but normal hoses ) for better performance on the primary second stage. These are mostly going away now.

I still use my Conshelf XII it has 7/16 LP ports.

 

[dsenloe]

A lot of Dacor regs used the 1/2" hose in an attempt to deliver more air , although this was never proven true. The female end for the second stage was a standard that fit everything while the male end was a 1/2x20 thread, different from the standard 3/8x24 thread on most regulators. It should ebay for 5-15 dollars

 

[DA Aquamaster]

The 1/2" port thing was a marketing gimic. The idea was that the larger 1/2" fitting with the assumed larger internal passage through the low pressure hose would allow more air flow. However as indicated in one of the posts above, many of these 1/2" fitting equipped hoses still had the same diameter hose with an air passage essentially the same as a standard 3/8" hose.

More importantly, no one made a second stage regulator with a larger orifice, so regardless of the internal diameter of the hose, the limitation in the flow of the system was still the size of the orifice in the second stage.

The argument was also made that a larger internal diameter of the LP hose would improve flow rate over the distance of the hose, despite the same restriction at the end (the second stage orifice), but this is only true to any practical extent if you use a very long low presure hose - as in a low pressure hose about 100 feet long. There is no measureable effect over the 22" to 84" lenght of the low pressure hoses used by scuba divers.

Thankfully, (unless you own a regulator with half inch ports, for which hoses are a bit less common) the 1/2" port fad has largely passed.

 

[ams511]

Thankfully, (unless you own a regulator with half inch ports, for which hoses are a bit less common) the 1/2" port fad has largely passed.

Actually I have a Beuchat reg that uses the 1/2" hose. I never noticed it before posting. The second stages look to be a rebranded TX-50 and TX-40, except without the "A" logo that are on my Zeagles. I took the covers off the Zeagles and the Beuchats and the insides look identical. The first stage on the Beuchat is very different looking than on the Zeagles and has the 1/2" hose. One of the tech dive sites in the UK suggests plugging the 1/2" port and using a regular hose with another port, which is probably what I will do. I still wonder if the first stage is an Apex or a Beuchat.