Compressed Air. How do I measure Compressed Air Volume Flow? 4

[Flosep]

Hi All,

Iam hoping someone can help me please. I need to measure the compressed air volume on 2 Blast Hole Drills. One machine is 1200 cfm & the second machine is 2000 cfm.

This is the compressed air the is delivered down the drilling rod. The compressed air is for (1) cooling the cutting tip & (2) to discharge the drilled material from the 16 meter deep hole.

The hole down the center of the Drilling Rod is 25mm Diameter on both machines & the pressure is 120 psi & apparently the full volume (1200 & 2000cfm) is suppose to be the delivery amount.

Can anyone please advise me on what equipment I need to use to measure this size air volume & pressure.

Many Thanks, Flosep

 

[BigInch]

Is the capacity of the compressor given as 1200 and 2000 Standard cubic feet per minute and you want to know the volume delivered at 120 psig?

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Flosep]

Hi BigInch,

Yes, the 1200 & 2000 is the standard cfm the compressors deliver.

I have a table & it shows that at 120 psi through a 1" Dia hole, can/should deliver 1951 cfm, so that is close enough.

The problem is,that the tips are over heating & the dust is not effeciently discharging from the hole.

Everything has been checked in the way of pressures, looked for blockages & any restricted pipes & nothing can be found.

The 1200cfm machine is the old machine & we feel it has decreased its capability with age & is expected. The 2000cfm machine is brand new & also not performing.

The supplier also is not helping or responing, so we want to measure the air flow ourselves to see what the old machine is doing & get a Base Measurment for the new machine for when it ages, but also to notify the supplier/manufacturer that it is not doing what it is suppose too.

This is why we want to measure it. (1) We want to measure its capacity at the Delivery Outlet of the compressor & then (2) measure close (say about 1 meter from) to the actual outlet of the drilling rod.

Kind Regards & Many Thanks

 

[miningman]

Is this an ITH machine or a conventional rotary/percussive or a top drive??? What diameter is the bit? General geology... hard granite or softer shale type rock?? I may be able to supply some suggestions to supplement your present line of investigation.

 

[gmax137]

I worked at a facility where we rented diesel-driven air compressors (900 scfm at 120 psig) - the rental company had air flow meters that threaded right onto the machine discharge pipe, upstream of the hose...

 

[Flosep]

Hi Mining Man,

It is a Screw Compressor. The Bit is about 200mm Dia. (Im not on site at present). The Geology is shale in an open cut coal mine.

I have also attached 2 photos.

Hope you can help.

Many Thanks & Kind Regards

Flosep

 

[Flosep]

Hi Gmax 137

Do you know who the Hire company was or what was the brand name of the instrument. (Im in Australia)

Many Thanks & Kind Regards
Flosep

 

[gmax137]

Hi Flosep - my experience was with Atlas Copco compressors, in Florida, USA (dont remember who the rental company was). It was a long time ago, I dont remember much about the meters themselves. I'm thinking they were rotameters of some type, the indicator was a ball that moved up in a cone shaped clear plastic thing...

 

[Bribyk]

Underbalanced drilling equipment, which is very similar to what you're doing, only a foam/water solution is added, used orifice plates to measure air (nitrogen) flow.

If it is very hot (like an Australian mine), you will have trouble making the rated/required airflow rate. See if you can get the compressors to draw cooler air from somewhere, they may be sucking in the air coming off their own coolers. The cooler the air you draw the more flow you'll end up with plus the air will be cooler coming out; giving you a double-benefit.

You might consider doing this operation at night, if you're not going 24 hours a day, I've ran similar-sized screw compressors with diesel drivers and I much preferred the night shift.

Your compressors may just be worn out too, our older iron always put out less volume.

 

[BigInch]

Right the SCFM is probably rated at something like 70F and sea level.

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[miningman]

Flosep, previous posters have given advice as to measure your airflow. Personally I think you have a drilling problem , rather than an aiflow problem. This might be difficult for you to resolve unless you are on site but heres some points for you to consider.

Your photo shows what I would call a drag bit but I have never heard of a drag bit only 200 mm. Are you sure your dimensions are right?? If so , even 600 cfm should be more than adequate to clear the drill cuttings.

The fact that you are experiencing this problem on two separate machines suggests to me that its not a compressor output problem.... altho previous posters suggestions on air temperature could be relevant.

You did not answer as to what type of drill rig it is, but a drag bit suggests straight rotary. Have you changed operators lately?? What rotation speeds vs down pressures are you using on the drill?. Hot bits suggests possibly over grinding of the cuttings which suggests excessive rotation speed. Another possibility is excessive down pressure causing the bit to advance faster than the airflow can remove cuttings causing excess heat and wear.

If yiur drillers are really inexperienced, consider bringing in as consultants someone who is familiar with your machines / local geology. Shale is soft rock and with the right type of rig / drilling practices you should be able to go thru this stuff like butter.

 

[thewellguy]

Hi think miningman is on the right track. You also didn't mention how deep you are drilling a if the hole is producing water. If you a in a water bearing formation you need to take that into account. A 120 psi compressor can only lift the water/cutting from a depth of roughly 277 feet. Have you exceeded the lift of the compressor?