Text 5350, 68 rader
Skriven 2005-01-28 17:40:07 av Stewart Arnett (3:772/100)
   Kommentar till text 5326 av Robert Bashe (2:2448/44)
Ärende: Tire inflation
======================
Hello Robert.

24 Jan 05 14:40, you wrote to Bob Seaborn:

 RB> Bob Seaborn wrote to Robert Bashe on Sunday January 23 2005 at 21:56:

 RB>>> Amazing. The quality of such equipment appears to have really
 RB>>> gone down since I lived in the States. As I noted, I've never
 RB>>> seen a compressor without at least an oil trap. But my experience
 RB>>> is obviously outdated.

 BS>> And I regularly see them with oil-inserter's, to help lubricate
 BS>> air tools.  :)

 RB> Seems strange to me, as I've never seen anything except for systems to
 RB> clean the compressed air.

It's not so strange if you consider the the difference in the requirement of
air tools and compressors. Air compressors compress air (duh) and during this
produce a lot of heat and in the case of piston (reciprocating) compressors the
compression ratio is very high. A BroomWade VML2000 has a piston stroke of some
8 inches with a bump clearance top and bottom of 20 thou' on  the low pressure
piston. The requirement for lubricating oil in this situation is an oil that
will not carbonise or combust under compression. If you take a good quality
lubricating oil, Talpa 20 or similar and heat it to 400 degrees C for a few
minutes, then check the colour you will find it has darkened, several more
heating sesions and it will look like treacle and have a similar consistency
when it cools down. Compressor oils have to withstand this treatment without
degregation.

Using the lub' oil in a compressor will eventually lead to the pistons, valves
and heads becoming coated with hard and soft carbon deposits. The pipe lines
and air recievers will become coated internally with sticky treacle like burnt
oil and possibly one day make flash off (ignite) the results of a reciever fire
are quite spectacular. Safety valves and pressure controllers can get glued
shut etc...etc. I've seen plenty of dead compressors from bad maintenance, but
fortunately only one explosion, and this occured on a weekend while no one was
in attendance at the factory. The explosion blew the compressor house, a
corrogated iron shed, to smithereans (sp) the back of the factory faced an area
of mangove swamps so real damage was done there, but the inside of the factory
was badly damage from the scrapnel from the compressor cylinders and heads as
they parted company from the rest of the machine. Using a compressor oil will
let the airflow carry the oil residue out from the machine to either filters,
traps or such or just blow out out the air line (into the tyres on your car).

Thus the need for cleaning the air as it leaves the reciever and enters the
reticulation system. If the air is clean then air tools will need lubrication,
and if the air is not clean the air tools will not like the shit and die
anyway. So a compressor oil's viscosity will not change (or change very little)
during the compression cycle and thus will contaminate the compressed air. This
will cause little harm to most things, but is better removed at the air
reciever as eventually it will build up and become a nuiscience. And as the air
powered equipment used on the system is now getting clean oil free air, and if
the requisit dryers and filters are used it will be very clean and dry air.
Then there will be a need for lubricationto be added to the air, using the
correct type of oils etc for the equipment used.

It is worth remembering that engine oil is not good in a compressor.

 RB> Cheers, Bob

 RB> -+- GoldED+/W32 1.1.5-0613
 RB>  + Origin: Jabberwocky System - 02363-56073 ISDN/V34 (2:2448/44)

Stewart

--- GoldED/2 3.0.1
 * Origin: The RockBBS Auckland NZ 64-9-5799600 (3:772/100)