ScubaScotty561
Contributor
What do they do?
What does a manifold do?
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FWADIVER
Contributor
allow you to use double tanks as a single gas supply and isolate them to prevent a total gas failure.
OP
ScubaScotty561
Contributor
Do you have to use a special reg when using a manifold?
ajduplessis
Contributor
The manifold connects two cylinders to form a “single” larger breathing gas source. The system have 2 pillar valves (thus two 1st stages needed each with its own second) and an isolating valve that can be used to separate the 2 cylinders in the event of regulator/hose failure on either side.
FWADIVER
Contributor
no, typically a manifold will have either yolk or din valves.
Close, but no banana. A manifold connects two or more tanks, allowing one or more regulators to access air from all the tanks. Manifolds often, but not always, also have isolator valves allowing air from one or more tank to be shut off from the system.
Isolators have gained popularity in recent years. The value of having an isolator in a manifold is a matter of opinion. They create an additional failure point in order to protect against one of two extremely unlikely possibilities - neck o-ring failure and burst disk failure. I prefer a manifold with no isolator.
Isolators have gained popularity in recent years. The value of having an isolator in a manifold is a matter of opinion. They create an additional failure point in order to protect against one of two extremely unlikely possibilities - neck o-ring failure and burst disk failure. I prefer a manifold with no isolator.
ajduplessis
Contributor
Like Walter stated, it's a matter of opinion!
DevonDiver
N/A
The manifold is the 'bar' that joins the two cylinders (see below). Its purpose is to enable two tanks to work as one 'virtual' tank - delivering the full contents of both tanks to either regulator.
Divers attach a regulator to both tank valves. Typically, these are DIN fitting regulators. These regulators are then used in a normal fashion, with one regulator (the 'primary') in the divers' mouth and a reserve regulator (the 'secondary') fulfilling the role of an alternate-air-source (AAS).
When using double cylinders, many divers prefer to use a long (5' or 7') hose as their primary and a short (22 - 24") hose as their secondary. In this instance, they will donate their primary 'long' hose to an out-of-air diver and then transfer to breathe from their own secondary regulator. The secondary regulator is typically secured on their neck, using a necklace made out of bungee cord. The long hose is kept streamlined by routing it around the body and behind the neck. From that position, it is easily and instantly deployable in an emergency.
The use of long and short hose combinations, in conjunction with the bungee necklace is often called a 'Hogarthian' configuration. It looks like this:
Manifolds come with, or without, an isolation valve (the knob at the top). Most divers prefer to have the isolation valve, because it enables them to close the link between two cylinders in the event of a valve failure on either of the cylinder valves. This preserves any remaining gas in the working cylinder.
As you can see from the diagram (above), the manifold accesses air from the cylinder from below the cylinder valves. This means that the link between the two cylinders is always open unless the isolator is closed. Because of that design, the diver can close either of the cylinder valves and still access air from both cylinders via the other regulator. This means that in the event of a regulator failure (free-flow etc), the diver can shut-down the failed regulator, but still access their total gas supply through the other regulator.
When properly configured, an isolated manifold set of doubles allows the diver to access all of their gas, from either regulator, even if they have toshut-down one of the cylinders. It also enables them to isolate either cylinder in the event of catastrophic valve failure. Overall, it is a very flexible and redundant system of diving.
Divers attach a regulator to both tank valves. Typically, these are DIN fitting regulators. These regulators are then used in a normal fashion, with one regulator (the 'primary') in the divers' mouth and a reserve regulator (the 'secondary') fulfilling the role of an alternate-air-source (AAS).
When using double cylinders, many divers prefer to use a long (5' or 7') hose as their primary and a short (22 - 24") hose as their secondary. In this instance, they will donate their primary 'long' hose to an out-of-air diver and then transfer to breathe from their own secondary regulator. The secondary regulator is typically secured on their neck, using a necklace made out of bungee cord. The long hose is kept streamlined by routing it around the body and behind the neck. From that position, it is easily and instantly deployable in an emergency.
The use of long and short hose combinations, in conjunction with the bungee necklace is often called a 'Hogarthian' configuration. It looks like this:
Manifolds come with, or without, an isolation valve (the knob at the top). Most divers prefer to have the isolation valve, because it enables them to close the link between two cylinders in the event of a valve failure on either of the cylinder valves. This preserves any remaining gas in the working cylinder.
As you can see from the diagram (above), the manifold accesses air from the cylinder from below the cylinder valves. This means that the link between the two cylinders is always open unless the isolator is closed. Because of that design, the diver can close either of the cylinder valves and still access air from both cylinders via the other regulator. This means that in the event of a regulator failure (free-flow etc), the diver can shut-down the failed regulator, but still access their total gas supply through the other regulator.
When properly configured, an isolated manifold set of doubles allows the diver to access all of their gas, from either regulator, even if they have toshut-down one of the cylinders. It also enables them to isolate either cylinder in the event of catastrophic valve failure. Overall, it is a very flexible and redundant system of diving.
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OP
ScubaScotty561
Contributor
I noticed those things you attach the manifold to on the sides of the tank and now know what their used for. But how come when you turn a tank on air doesn't come out of that part as well as the valve. I may be making this sound a little confusing, but i'm talking about when you're only using one tank and no manifold, how come the air doesn't come out of that side thing. Does that side valve thing only work when a manifold is attached to it? Sorry if this is confusing some people.
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