Advanced/Technical diving and mechanical aptitude

[halocline]

The main thing to look for when you get it serviced is to make sure it's been tested on a flow bench to ensure proper flow.

Here, Read this:
Demystifying Regulator Repairs

I read that, it's basically an ad for an expensive tool that really does very little. It practically says as much if you read carefully. I think it's an interesting tool to evaluate flow characteristics and venturi effect, but since there's very little you can do once you set a reg's cracking effort, IP, and venturi assist in terms of increasing flow, what use does it have?

And, it's not really accurate for the design limits of a reg unless you have a serious air source with MUCH higher flow than a tank valve and the ability to maintain constant pressure.

You can tell a great deal about a reg's performance with an IP gauge, 2 tanks (one full, one near empty) and a sink full of water. To be honest, I couldn't care less if my D300s open at .7" or .9" of water. I just set them as low as I can get them and dive. For regs with more case fault geometry issues (like practically all conventional 2nd stages) the sink does a good job of helping you set cracking effort so that the reg is stable when the exhaust valve is shallower than the diaphragm. You just make sure the reg does not flow before the exhaust valve is submerged. (You can actually get away with a little lighter cracking effort, because differences in pressure/depth are greatest at the surface, but setting it this way ensures that case fault geometry will never cause the reg to freeflow)

Regulators operate in water, it makes sense to use water to test them. For me, the "main thing" is not that the tech has a machine to spit out numbers, but to make sure the tech has a good understanding of how the reg actually functions, and takes his/her time to do a thorough job of cleaning and careful reassembly.

 

[Meister481]

I read that, it's basically an ad for an expensive tool that really does very little. It practically says as much if you read carefully. I think it's an interesting tool to evaluate flow characteristics and venturi effect, but since there's very little you can do once you set a reg's cracking effort, IP, and venturi assist in terms of increasing flow, what use does it have?

And, it's not really accurate for the design limits of a reg unless you have a serious air source with MUCH higher flow than a tank valve and the ability to maintain constant pressure.

You can tell a great deal about a reg's performance with an IP gauge, 2 tanks (one full, one near empty) and a sink full of water. To be honest, I couldn't care less if my D300s open at .7" or .9" of water. I just set them as low as I can get them and dive. For regs with more case fault geometry issues (like practically all conventional 2nd stages) the sink does a good job of helping you set cracking effort so that the reg is stable when the exhaust valve is shallower than the diaphragm. You just make sure the reg does not flow before the exhaust valve is submerged. (You can actually get away with a little lighter cracking effort, because differences in pressure/depth are greatest at the surface, but setting it this way ensures that case fault geometry will never cause the reg to freeflow)

Regulators operate in water, it makes sense to use water to test them. For me, the "main thing" is not that the tech has a machine to spit out numbers, but to make sure the tech has a good understanding of how the reg actually functions, and takes his/her time to do a thorough job of cleaning and careful reassembly.

I keep forgetting that the bucket of water allows you to benchmark regs and if a reg is not operating to spec you can look into the problem. The difference between .7 and .9 is noticeable enough that I would want to verify the parts are seating properly if the reg is deviating that much. I personally like mine to crack at .6 or .7 for tech regs and .8 for pool/OW regs.

I personally use the system to verify the amount of flow that can hit the second stage is consistent with the regs design capabilities. Should there be a problem and you don't figure it out until you are drawing hard on the reg, then you have a serious problem. I just prefer a more scientific method that allows for a controlled assessment of the system before I send a reg out for a customer to use in any hazardous environment. If the shuttle is installed backwards in a Micra you wouldn't know it by dumping it in a bucket of water, but in a test such as this you would.

How many times has it been said to test your equipment after service to ensure it works properly? This system pretests the unit to extremes that should never be seen while diving, and ensures reliability and safety. We charge no extra for the service and give the customer a printout of how the reg tested on the flow bench. We will even set your reg to crack at the setpoint (within spec) you wish.

 

[halocline]

Well, it's nice that you want your regs to crack at .6", but if the exhaust valve is more than .6" shallower than the diaphragm, it's going to freeflow. This is something that a vacuum gauge will not tell you.

And yes, my tests do tell me if the reg is performing at it's best.

I'm not saying that a bench flow test is a bad thing at all. I just think it's not "the main thing" in regulator service, and I think that article was basically pushing the machine.