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John Strachan
John Strachan • Aug 23, 2018

Graduate trying to figure out why these compressors were purchased?

Hi everyone, I've just started working with a company and been tasked with solving our compressor issue.... 😏 

We basically need 14 bars of pressure at each of our 21 laser machines. I have attached a small diagram I made of the system. My question is; why would someone buy six compressors if only two are ever working and are 1:2 boosters actually going to give us double?

On paper the science is sound here but I was hoping for a little direct experience.

Thank you very much in advance!


It appears that the six compressors are in parallel. The outlet set pressure controls the operation cycle. If each compressor has its own control settings it is possible that only those units set for the highest pressure would work. The rest will see a higher than set outlet pressure and will remain off.

Since there seems to be a booster for each laser m/c it would be better to connect one compressor to two lasers. Then all will work.

I wonder why anyone would connect compressors in parallel.

John Strachan
John Strachan • Aug 24, 2018

Hi Ramani, thank you for your input and advice! I think the system was chosen for expansion but the big mistake here is the lack of pressure. 

The project was advised to purchase 2x 9.75bar comp. and 4x 12.75bar comp. Yet only two ever function here. Also the solution for higher pressure is to use the air boosters which I think is highly inefficient.

What do you think, sell the system and buy two 16 bar compressors with higher capacity storage tanks?

What do you think, sell the system and buy two 16 bar compressors with higher capacity storage tanks?

Worth looking at.

There is a no brainer option.

Use a single master sensor for the high pressure cut off and the low pressure cut in . Switch on all six compressors and switch all off together.

My feeling is that the drop in pressure seen is caused by the inadequate volumetric output in the system as a whole since only two compressors operate. If the suggested scheme is implemented a threefold increase in capacity will be realised.

The main advantage is that nothing need be changed in the hardware. This can be tested at once.

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