We will meet or beat our local competitor pricing on equivalent training and equipment!
Certified professional diving equipment service!
Dive Equipment Services
Adventure Diving certified technicians will keep your equipment in excellent
repair! We use all oxygen compatible repair kits and all gear is certified to use
Adventure Diving can perform the following diving equipment services:
Regulator Annual Service
Buoyancy Control Device Annual Service
Cylinder Visual Inspection and Valve Services Including Visual Inspection Plus
Dry Suit Repairs and Valve Services
Dive Computer Battery Repair and Maintenance
Wet Suit Repairs
Equipment setup and testing
Custom Repairs and Maintenance
Call us at 255-7282 for more information.
Complete cylinder service should include checking the hydro test date is within the five year span, a yearly visual inspection, oxygen cleaning, visual plus eddy current test, blow out disk replacement, valve overhaul, and proper labeling. Anything short of this is insufficient! The visual inspection checks for obvious dents, bulges, cracks, oxidation, thread damage, and hydro test date. Oxygen cleaning removes hydrocarbons and kills bacteria the could be ingested during respiration.Thevisual plus eddy current test checks for dangerous cracks in the thread and neck area which can be compared year to year for changes.
The blow out disk can oxidize and blow out at a lower pressure than specified for the application or even during a dive! Valves should be overhauled to repair or replace worn or oxidized parts and replace lubricant for a safe dive also. Proper labeling is very important to know the date of the next hydro, visual, and gas contents.
Burst or blow out disk information!
Cylinders and Burst
There is a myth that leaving a SCUBA cylinder in the trunk of a car places the cylinder in serious danger of blowing a burst disk. This is not likely, especially with new equipment. This would only happen if the burst disk is fatigued, and well out-of-spec on the low end of its rating. The purpose of the burst disk is not to protect the cylinder from solar heat in the trunk of a car. The burst disk purpose is to protect the cylinder if left unattended while filling from a running compressor that has a rating well above the cylinder rating, and possibly protecting the compressor, though most compressors have their own pressure relief valve. Burst disk are designed to burst at well above the cylinder rating - often around 40% above nominal. For a single aluminum 80 cylinder, that would be:
3000 PSI x 1.4 = 4200 PSI.
Charles' Law states that: (Pressure x Volume)/Temperature is constant, meaning that pressure rises with temperature to keep their ratio a constant if the volume remains the same. This can be expressed as:
P1 / T1 = P2 / T2
Many people believe that a 140 degree F trunk vs. a 100 degree F fill temperature would yield a 40 percent increase in cylinder pressure:
3000/100 = P2/140, or P2 = (3000/100) x 140 = 4200 PSI
BUT!!!..... It doesn't work that way because the pressures are relative to "absolute zero" temperature (-460 degrees F). Degrees Rankin equal Fahrenheit degrees in size, but measured relative to absolute zero. Since the equation for Charles' Law is based on degrees Rankin, the example above is correctly calculated as follows:
3000 / (460 + 100) = P2/(460 + 140)
3000 / 560 =P2 / 600
P2= (3000 / 560) x 600 = 3215 PSI
This value is well below burst disk concerns. The burst pressure is rated at nearly 1000 PSI above the expected 215 PSI rise in a 140 degree Texas trunk in the 100 degree summer day (assumed temperature for rated pressure in the summer). If you fill the cylinder in an 80 degree room/water tank, the rise would be greater relative to the filling pressure, but well under 4200 in the example.
3000 / (460+80) = P2 / (460 + 140)
3000 / 540 =P2 / 600
P2= (3000 / 540) x 600 = 3333 PSI
This value is still only about 11% over rating, and within tank safety margins. Cylinder tip! - Store your cylinder with very low pressure (500 PSI) to keep water out and material stress low. If that isn't practical, store it full. In a house fire, the burst disk may blow from heat combined with pressure if the storage pressure is high. If the aluminum cylinder is half full, the cylinder will likely give way before the burst disk because aluminum is severely weakened by extreme heat, and the pressure rise might never reach the rated burst temperature before catastrophic failure of the cylinder.
Copyright © 1998 - 2006
Randall C. Allen
All rights reserved
References: Compressed Gas Association and several cylinder manufacturers!
Complete buoyancy control device yearly overhaul should include pressure testing the bladder, checking for leaks, cleaning the bladder inside and out with an approved cleaning agent, checking for strap and material wear, and overhaul of all inflation and dump devices. If everything is checked, overhauled, and tested, it may the be marked or tagged for return to safe service!
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© 2005 Adventure Diving All rights reserved.