Air Pressure question

The problem is my employer has a Main line coming off the 3" Airline Pipe. It goes from the pipe through a 1.5" hose into a 3/4" T fittings where it splits and goes to 2 seperate Air Regulators which eac h go to a seperate Air Horn. The Main Line Pressure is abou 120-135PSI.

The problem is these things are only getting 60-70PSI turn all the way up and they are not sucking out the Boric Acid properly.

I am guessing its because its split at the regulators. If Its split at where it comes off the main 3" pipe or if I beefed up the 3/4" to 1.5" where it splits can I get an increase of pressure?



The regulators are obviously splitting the Pressure. They each get 65PSI when the Main is 135PSI ish. Even though they are Split with a T pipe fitting, I dont get this. It does make logical sense but each station also has a seperate Regulator coming from the main 3" Air Pipe. Technically this is splitting the Air off the Main Line, just on a bigger scale, so why can these regulator get up to the full main pressure instead od the Pressure being divided by the number of regulators? Is it jus how clost the splits take place at? I included a crude pic to illustrate what Im asking.

???! NO, it is physically impossible that the regulators are "splitting" the upstream pressure. Look at the part number on the regulators and you will probably find that the range is 0-60PSI. This may have been done deliberately for the purpose of preventing someone from cranking up the pressure to high. Only other explanation is that you have a lot of leakage somewhere or the demand for flow is higher than the regulator can provide.

Yes, the only other thing is the demsnd of the air horns - can you shut one off to try it?

I think more info is needed ie what is length of the airlines from the header? If these horns are high volume then at a high flow there will be a pressure drop. The regulators may be undersized and unable to deliver the volume demanded by the horns.

I would put a pressure gage upstream of each regulator and read at full flow. Then I would determine the volume demanded by each horn and match with a suitable size regulator plus 10%.

Dan Bentler

Dan is right. You can't talk about flow rate and pressure separately any more than you can talk about voltage drop without discussing amperage. Pressure drop = restriction times flow^2.

Main line is the 3" Airline Pipe which goes the length of the plant. It goes from the main pipe through a 1.5" hose which is about 6 feet long into a 3/4" T fitting where it splits and goes to 2 seperate Air Regulators. The length od 3/4" pipe from the T fitting is only 8-10" long to each regulator. Then a 1" diameter hose about 6 feet long goes to the regulator. The regulator says 145PSI max.

But its weird because when I put one regulator at 0 PSI I still can only get the other regulator up to 80PSI. But when I increase the Pressure of the other regulator they will only get up to 75 PSI.


Im starting to think this has to do more with the Airhorns. If they are not restricting the air flow enough you can only get the pressure up so much,correct? If I hooked 200PSI straight to the Airhorn it will cause an Pressure drop correct? Because the Air horn has high CFMs.

Skiroy said:

Main line is the 3" Airline Pipe which goes the length of the plant. It goes from the main pipe through a 1.5" hose which is about 6 feet long into a 3/4" T fitting where it splits and goes to 2 seperate Air Regulators. The length od 3/4" pipe from the T fitting is only 8-10" long to each regulator. Then a 1" diameter hose about 6 feet long goes to the regulator. The regulator says 145PSI max.

But its weird because when I put one regulator at 0 PSI I still can only get the other regulator up to 80PSI. But when I increase the Pressure of the other regulator they will only get up to 75 PSI.


Im starting to think this has to do more with the Airhorns. If they are not restricting the air flow enough you can only get the pressure up so much,correct? If I hooked 200PSI straight to the Airhorn it will cause an Pressure drop correct? Because the Air horn has high CFMs.

Click to expand...

Now that you have done this the next step is to determine what your load is ie how much air the horns demand look for CFM.
THEN make sure the CFM and the pressure rating for the regulators exceed the same values on the horn.

Check delivery pressure on regulators they may be able to do only 80 psi.

Dan Bentler

A1/2 inch hole will allow 200cfm(aprox) to pass @100psi. Factor in the length of pipe the drop will be about 2psi each foot of hose. Check the pressure when the horns are off/isolated, the pressure should be the same as the mains, if it is not then your regulators are faulty and may need replacing or need new diaphragms. If the pressure is the same when the horns are off the run 1 if the pressure drops then it is using more air than that can be supplied.

Skiroy,

I took your drawing and added regulators. To diagnose your condition add the air pressure gauges where I have indicated. We will need the readings with the horns on and with the horns off. One thing I have not heard discussed is the valve(s) that turn on the horns. Can you describe where it(they) is(are)?

If I misinterpreted your setup can you provide a better description or drawing?

Skiroy said:

Im starting to think this has to do more with the Airhorns. If they are not restricting the air flow enough you can only get the pressure up so much,correct? If I hooked 200PSI straight to the Airhorn it will cause an Pressure drop correct? Because the Air horn has high CFMs.

Click to expand...

You need regulators and accumulation capable of supplying the CFM.

You may do well with grossly oversized regulators and big hoses leading up to the air horn control valves mounted right on the horns...depends on duty cycle and what you have to work with.

Where are your control valves for the horns?

What kind of Horn? your link took me to an ebay search.

EDIT: I hope you didn't try to hook up truckers' air horns to a plant supply...

What's that cfm and pressure rating say on that there horn again?

Once again

KNOW THY LOAD

Dan Bentler

OkiePC said:

You need regulators and accumulation capable of supplying the CFM.

You may do well with grossly oversized regulators and big hoses leading up to the air horn control valves mounted right on the horns...depends on duty cycle and what you have to work with.

Where are your control valves for the horns?

What kind of Horn? your link took me to an ebay search.

EDIT: I hope you didn't try to hook up truckers' air horns to a plant supply...

What's that cfm and pressure rating say on that there horn again?

Click to expand...

I did this once - we had some air horns from a fire engine - I nearly **it my pants they were that loud!!!!

At a previous plant i worked at, the old maintenance manager got tired of people using the excuse of "We didn't know break was over" when taking extra long breaks. He hooked up a train air horn in the middle of the plant connected to the time clock. Even full of dust with a glove zip tied over it, it was deafening.

Served its purpose though.

If the horns can operate on mainline pressure of 120-135psi, why not remove the regulators and pipe straight thru to the horn's control solenoid valve. That way, the horns get the maximum pressure possible with the existing piping. If there is too much pressure drop in the piping, it would be relatively easy to find the tight spot and increase its side.

Now that you have done this the next step is to determine what your load is ie how much air the horns demand look for CFM.
THEN make sure the CFM and the pressure rating for the regulators exceed the same values on the horn.

Check delivery pressure on regulators they may be able to do only 80 psi.

Click to expand...

I agree with Dan's comments. Also if you remove the regulators you may drag the system pressure down unnecessarily.