Equipment Resources Question

[ianw2]

I'm in the same DM class as SharkDZ. We take our exams next Wednesday.

I have degrees in Chemistry and Biochemistry and have no fears or worries over the Physics or Phsiology portions of the exam.

What errifies me is the Equipment portion. I just don't get the diagrams on 1st and 2nd stage regulators in the encyclopedia.

Does ANYONE have a resource for understanding what the heck is going on with these pieces?

Thanks...


Ian

 

[SharkDZ]

Pssst! (Sit next to me during the exams...) :11:

 

[Bubble Junky]

The equipment exam doesn't go into that much detail. You don't need to memorise the diagrams or anything. It's all multiple-guess for that exam too, so the answer will be right in front of you.

 

[GA Under Water]

I did the Equipment Exam lastnight. So far the easiest exam I have 2 more to go.

Learn the basics and study the sidebars also. I guess I can't go into detail because it would be more of a "Brain Dump" I don't want to give anything away. The diagrams, , , just read about them and make sure you can see in your mind what happens as you breath.

I personally thought the Rescue Manual gave the easiest description on page 72.

 

[ianw2]

Thanks!

But, based on the diagrams in the book, I can't get my head around the details of how the parts are moving. I thought I had an idea until I looked at the drawings...then, the wheels fell off!

Are there any better drawings anywhere?

Ian

 

[Joe-Diver]

What are you trying to get straight? How a first stage works? How a second stage works? The difference between a balanced and unbalanced first stage? A pilot valve second?

 

[GA Under Water]

Just start at your mouthpiece

Inhale:
1 you inhale
2 Vacume created inside 2nd stage
3 Diaphragm is sucked in
4 diaphragm actuates lever
5 Lever opens valve at hose to let air flow from 1st stage
6 air leaving hose creates low pressure in intermediate chamber
7 spring and lower pressure Open Valve to High pressure chamber

Exhale:

1 you exhale
2 diaphragm returns
3 releases lever
4 lever closes valve Excess air flows out exhaust valve
5 pressure builds in hose
6 pressure builds in intermediate Chamber
7 forces piston to compress spring and close High pressure valve

Return to Inhale

Least that is how I explained it to myself in my head. Diaphragmed 1st stages are a little different but once you get your head wrapped around the air flow you can figure it out.

 

[muddiver]

Regulator basics:

1. Pressure in cylinder is around 3000 pounds per square inch (psi)

2. An ajustable valve that will open when the pressure on the outside of it drops is attached to the cylinder and it has a spring that holds back the 3000 psi when the down stream pressure is at teh adjusted level (usually 135 psi).

3. Hose between valve on cylinder holds and transfers 135 psi air to valve stuck in divers mouth.

4. Valve in divers mouth uses a diaphragm that is pulled in when when diver inhales to push open a popet valve (think hand soap dispenser) that allows pressurized air in hose to exit in to diver.

5. Diaphragm returns to flat shape when diver exhales or stops breathing.

Pressure of sourounding water presses in on the diaphragm allowing air in to the regulator in the divers mouth which keeps the regulator and divers lungs at the same pressures as the water.

Please reply if this does not help.

 

[ianw2]

I understand WHAT it's supposed to be doing. I just can't make heads nor tails of the diagrams in the Encyclopedia. I was hoping that someone would have an animated Power Point Proentation or something similar showing what happens as I suck on my 2nd stage.

Ian

 

[Joe-Diver]

I think folks have described it well for you here....perhaps you should ask the repair tech at the shop you're working your DM with to show you? Take the Equipment Specialty course too...that will teach you quite alot. Not enough to be a repair tech of course...but if the person teaching it is a repair tech then you'll learn quite a bit.

AND....you can always ask for a review on this with your Instructor.....