UBUC

The Mobile Compressor

UBUC have a mobile compressor which we take on longer trips. It allows us to run extended trips to locations where there isn't a dive shop nearby to fill our bottles.

In August 2008 the compressor was tested and found to fill at a rate of 6.3 cubic feet per minute and uses 83 ml of fuel per minute.

The high pressure stage holds the filter. The aluminium filter cover has been removed in this picture.

The yellow o-ring guard sits on top of the o-ring

When replacing the aluminium high pressure stage cover make sure it it turned back 1/8 th of a turn off being fully tight. It will wobble just a little bit.

Cleaning the air filter - 1

Cleaning the air filter - 2 - the air filter is designed to hold a large number of insects and dust. Tap it away from the compressor to remove most of the dust.

Cleaning the air filter - 3 - Blow backwards through the filter with a cylinder to get rid of the rest.

The compressor has three valves which MUST be purged at least every 20 minutes. The high and low pressure valves only need to be opened a quarter of a turn, but the medium pressure valve needs to be turned through at least one complete turn before it opens. The relief valves for the three stages are shown in this picture:

This is the low pressure valve: 

This is the compressor oil reservoir. It needs to be checked and probably filled up at the beginning of each day's use. It's a flat reservior so takes quite a lot of oil just to raise the level by a few millimeters. The level should be kept to the bottom of the thread.

You need to be very very careful when replacing the compressor oil's lid. It is plastic and very easy to cross thread. Turn it backwards 1/16 of a turn or it will jam in.

DON'T tighten it like this. Just use the finger tips!

This is the dip stick for engine oil. We also do the oil changes via the dip stick hole! Replace the oil with SAE 10W-30.

Make sure the compressor is on the level when checking the oil level. There is a small circle on the stick. The oil level should be there.