Plumbing assistance please

[CraigAClark]

Too bad Tom Grubb passed. His auto-blender was a work of art. It had all the safety features anyone could ask for, including run and temp shut-offs for the compressor.

Craig

 

[Scuba Duck]

The Nitrox Controller was specifically developed to be compatible with the Envirodive Nitrox Stik. It automatically regulates the addition of oxygen to your continuous gas blender, and has several safety features...

Nuvair recently picked it up and now the nitrox controller can be purchased as an option for new LP 280 and LP 560 Membrane systems.

Rubber Duckie Designs Nitrox Controller, an Automated Control System for Blending Enriched Air Nitrox (EANx) for SCUBA

 

[CraigAClark]

Does this unit monitor the final discharge temp of the compressor? The auto-blender had a feature that would shut down the whole process should the final stage temp rise too high. It also featured a solenoid controled flow valve for the O2. There were many more features that could be programed into the unit.

Does this unit also take into consideration the O2 adjustments needed as the back pressure (lower intake demand on higher discharge pressure) increases?

Craig

 

[Scuba Duck]

The unit as presently designed monitors the output of the blending section and dynamically controls the proportional valve to regulate the oxygen content at the desired level. The system is very capable of regulating the oxygen content within 2/100's of one percent. In the membrane application, it also has a temperature sensor that compensates for the effect that heating the permeate has on the oxygen sensor.

It has an auto shut down feature that immediately closes the oxygen valve should the compressor shut down, without waiting for the feedback from the down stream oxygen sensor. The system will not open the oxygen valve, unless the compressor is running.

The controller is designed such that you can put the monitor in one location, and the rest of the equipment in another, and essentially use the system as a remote control. This is very practical for those dive shop applications where the compressor is in a separate, adjacent building.

It has audible alarms to notify the operator of anomolous conditions, specifically should the oxygen go out of specification. The most common scenario when this happens is when the oxygen cylinder goes empty.

There are a host of other possible features that could be incorporated, but they drive up the cost of the system. We felt that the features designed into the present system were a good mix of performance, simplicity, reliability, safety and cost. If there are additional features that you would like to have, let us know, and we could probably incorporate them.

 

[iain/hsm]

Too bad Tom Grubb passed. His auto-blender was a work of art. It had all the safety features anyone could ask for, including run and temp shut-offs for the compressor. Craig

Craig.
I am so sorry to hear about Tom Grubb, this is the first I had heard, we used to chat with him at the DEMA show, in fact only last month we spoke about him while on a service job, a 35scfm 5000psi 4stage compressor, after we finished servicing the customers nitrox people came in to hooked up a new nitrox 50% blender.

Looked like an aluminium rectangular box blender box section with internal baffles with a standard medical type single stage regulator hooked to four oxygen cylinders on a rack manifold, needle valve and relief valve all hooked up with 3/8 stainless to the blending box. Heck of a fiddle to get the adjustment right, took some fine adjustment before it held firm at 50%, I sat baby sitting the compressor while the rest of them were next door to the filling bay, as the cylinder supply pressure dropped (and they do pretty quickly at 50% and 35acfm) I noticed the percentage had risen to 73% nitrox. I guess Tom would have had a “field day” with them for that, had he known. Iain

 

[CraigAClark]

Craig.
I am so sorry to hear about Tom Grubb, this is the first I had heard, we used to chat with him at the DEMA show, in fact only last month we spoke about him while on a service job, a 35scfm 5000psi 4stage compressor, after we finished servicing the customers nitrox people came in to hooked up a new nitrox 50% blender.

Looked like an aluminium rectangular box blender box section with internal baffles with a standard medical type single stage regulator hooked to four oxygen cylinders on a rack manifold, needle valve and relief valve all hooked up with 3/8 stainless to the blending box. Heck of a fiddle to get the adjustment right, took some fine adjustment before it held firm at 50%, I sat baby sitting the compressor while the rest of them were next door to the filling bay, as the cylinder supply pressure dropped (and they do pretty quickly at 50% and 35acfm) I noticed the percentage had risen to 73% nitrox. I guess Tom would have had a “field day” with them for that, had he known. Iain

Iain,
If I recall he passed on Christmas eve either in '04 or '05. He had been battling cancer. I don't think his wife, Holly, kept Machine Design open.

Craig