Pressurized CO2 System

By Dominic Prakash

Introduction

In this article I am going to explain how I set up my first pressurized CO2 system. My initial concern was to keep a pressurized cylinder in my living room. The main reason for this is my 18 months old baby (when I start writing this article) and he wants to explore everything. So I was looking for the smallest CO2 cylinder available in the market to hide it under my aquarium.

CO2 Cylinder Danger?

I am giving this section before other sections because it’s very, very important. Please consider this and all of this information very seriously. I refilled my 5lb cylinder and came home and placed it in my garage corner. After say 30 to 45 minutes, there was a huge sound. That was not a blast, but continuous “hissing” started with a huge one. Good that no one was nearby. The reason, My cylinder’s safety valve had blown. It took few hours for us to recover from that shock. Next day I took my cylinder back to the refill station. They replaced the safety valve. Actually it’s not due to the safety valve or the cylinder. In fact it’s a brand new cylinder and the date stamp is just 4 months old from today.

The main cause for this blow is overfilling the cylinder. Generally these welding suppliers used to refill 20lb or more capacity big cylinders. In those cases even if they fill little bit more, it will not be a problem because of their size. But if they over fill the smallest cylinder (5 lb) like mine, and when the cylinder reaches room temperature then surely the safety valve will go off. So during the second time I specifically asked them to fill “JUST” 5lb or little less than 5lb. Also I left the tank in their office for about 6 hours. Then I kept it in my garage for about two days (just to make sure). [Actually my wife did not allow it inside]

Another important point is to educate and inform you family member about the cylinder and the “type” of gas inside. Actually my wife thought it was some sort of an inflammable gas and she was about to get out the house with our baby.

Note: After refilling it would be a good idea to install regulator and monitor cylinder pressure. Make sure that’s not going beyond the “Green Area” of your gauge [approx. 1000 psi].

CO2 Cylinder and Regulator

I searched a lot to find one small (5 pound) CO2 cylinder. First I searched it in my yellow pages under “Welding Equipment & Supplies” and “Beer Homebrewing Equipment & Supplies“. Most of my local suppliers (Welding and Beer) have minimum of 20lb cylinders. That’s huge for me and I cannot hide it under my aquarium. If you get it locally, and its NEW and its in the range of $50.00 to $60.00 (incl. tax) then go for it.

Then I started searching online. Few news group members suggested “RAPIDS Wholesale Equipment Company“. “RAPIDS” has really good prices if I compare them with other online vendors. Also they have all items as a kit and I need not buy bits and pieces. Next comes selection. I went with the Steel kit instead of Aluminum. For me Aluminum cylinder is little expensive (but cute and fancy) and I don’t see any extra benefits (for that extra $30). Anyway I am going to keep it under my aquarium, so steel is ok for me. Another very easy source is Fire Extinguisher cylinders.

[singlepic id=7] This kit comes with

  • 5lb New Steel Cylinder
  • Double gauge Regulator (TAP-RITE 700 Series)
  • 4ft CO2 tube.
  • Related Connectors

Due to height constraint I fitted my regulator little horizontally (Actually its 30 deg)

I paid $99.00 for this kit and shipping charges to my home is $14.00. You can locate the above kit from RAPIDS. If this link is not working then go to their online store. Select “Beverage Dispensing“, and then click “Kits“. You will find the Steel (Code: BD435) and Aluminum kit (Code: BD215). If you want just regulator go under regulator section you will find the above regulator (Code: 9T852).

Needle Valve, connectors and Air Tube

I found this was the most difficult part because I am very much new this. Most of the aquarium online stores have similar but “hi tech” needle valves. I don’t want to spend a fortune for that. So here is what I did, for measurement purpose I cut 1/2″ CO2 tube (the one that came with my cylinder) and took it with me to a near by Home Depot. One of the main problem which I faced was there are multiple size connectors for the same model number.

I bought 4ft of Polyethylene airline (1/4″) tube also from Home depot for $0.07/ft. I asked them to cut that tube by 1ft and 3ft. They have a cutting tool which is specifically designed to cut these kind of tubes. You will get a perfect cut (this will also reduce leaks).

[singlepic id=10]

Figure Identification # Part # Description
1 A-293 PB225 I.D. HOSE BARB TO MIP ADAPTER 3/8″ X 1/4
2 A-16 PB966-P TUBE TO FIP COUPL W/INSERT 1/4″ X 1/4″
3 A-42 PB9106-CP TUBE TO TUBE VALVE W/INSERT 1/4″

Adjusting the Needle Valve

If someone says you can’t adjust bubble rate with this “cheapo” needle valve, it’s not true. I can make few bubbles a minute to million bubbles a minute. You should be very careful with the “nut” just below the “T” and the regulator output pressure. Set the needle valve to the lowest possible level and tighten the “nut” to control further. My regulator output pressure set at 10-12 psi. I was told that if you go below that range the regulator may not “regulate” properly. I found that if it is more than 12psi I cannot control my needle valve.

[singlepic id=19] [singlepic id=28]

CO2 diffuser

Actually I don’t want to build my own diffuser because I may not really save anything. In fact I can save some time by not doing it myself. Few users from the news group suggested this setup. So I went and ordered a small internal filter [DUETTO MULTI INTERNAL FILTER – DJ50] from BigAls. Part number ASWO#16709. One good thing about this filter is, it has an air line injection mechanism to mix air with water. I can use this option to mix CO2 with water. More over this filter is just 12 bucks and it does little filtering too. Using a timer I can switch off this filter when there is no light.

This filter chops each CO2 bubble in to thousands of smaller bubbles (like pearling). It’s really nice to watch. To count number of bubbles per minute switch off the filter and count the big bubble that comes out of the outlet. If you would like to go in this route make sure that filter flow rate is set to “minimum”.

[singlepic id=20]

Parts and Price [As of October 2002]

Item Name Place Part # Price (US$)
5lb Cylinder, Regulator, Tube and S/H Rapids Wholesale BD435 113.00
Refilling 5lb CO2 Local Welding Sup 8.50
Adapter Home Depot 048643074491 1.25
Connector #2 Home Depot 048643070394 1.25
Needle Valve Lowes 25627 3.75
Teflon Tape Home Depot 1.00
Airline Tube ($0.07/ft) Home Depot 694892 0.50
Duetto Internal Filter (DJ50) BigAls 12.50
Total 142.00

General

* I used the word “CYLINDER” instead of “TANK” because cylinder will make you to think twice about safety.

* You may get most of the above parts from any of the home improvement stores. I went with respective home improvement store because of its proximity to my home.

Feedback

Could you please spend 10 more seconds by leaving your Name and contry information. Actually I dont want your e-mail id. bank account number and password. This is just know who was on here at my site.

Have a look at my Tank. “PMDD@Work”

[singlepic id=3 mode=watermark]

Reference

1. Eric Hanson’s article. Thanks to Eric for his help in setting up this Pressurized CO2 System.

If you see any errors or broken links please mail me

Copyright Info

  • Article and Images Copyright 2002 Dominic Prakash.
  • All parts and part names are belongs to respective Manufacturers.

Change History

  • July 20, 2011: Moved to new website
  • January 18, 2003: Font Change
  • November 26, 2002: Fixed few spell Errors; Fixed Broken image link.
  • November 05, 2002: Fixed few spell Errors; Included this change history.
  • October 30, 2002: Initial Version

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