tiopaeng said:
I don't have the hardware yet because this is a new project and I'm still putting the inventory together whatever is recommended in this forum. However the vessel is operational with manual control valves and we want to automate the controls.
Incoming air is 120psi on a 2" pipe and produced by a 50hp screw IR compresser with air receivers and there is no requirements as to how long it would take to fill the vessel around 4'W x 12'L. The vent valve can be any size as recommended.
TioPaeng
This operation involves blowers, safety interlocks, cooling, vacuum, air pressure, heating and everything is recorded through a chart recorder. By using a plc would automate the whole procedure.
Getting info from you is like pulling hen's teeth.
OK so here are the facts
1. You have a complicated interactive multiple system.
2. Part of the system requirement is compressed air at 80 plus or minus 8 psi
3. Air supply source is 120 psi and 50 HP.
4. this large tank 4 x 12 foot is apparently acting as reserve supply.
I think you are overlooking doing this the simple way with widely available controls ie standard pneumatic regulators.
What is the compressed air flow demand of the system??
You do not need to vent the tank
- just stop filling
COmpressed air is expensive - by venting you are taking those compressed air dollars and dumping them to atmosphere. If you can afford this waste please send me a check.
BUT you do have to install a pressure relief to prevent tank rupture. I would use two one set for 88 (or 90) and one for tank pressure rating.
Use a line regulator set for 88 psi to fill the tank. Also install a moisture trap since you are dropping pressure from 120 to 80.
Here is what I would do install a line direct from the compressor with a solenoid to feed 4x12 tank. If this line is parallel to others place check valves in all lines. This way you are not compressing to 120 to fill a 88 psi tank you are using the compressor to fill using maximum 88 (plus line drop) discharge pressure on compressor -- will save lots of power and you will still stay within pressure tolerances
Dan Bentler