Need help, Airfed mask related

[m5dkw82]

Not sure where to start, I am trying to run a devilbiss Prov and a Sata RP

Devilbiss says it uses 4.3 cfm and requires min 4 bar
Sata RP says it uses 10.3 cfm @ 29 psi (2 bar)

I have 2 compressors and a small air receiver

Compressor no1 is an old clarke raider 120, Max Pressure 10 bar, 100 ltr
400L/min (14 cfm approx) 3HP

Compressor no2 is a warrior, Working Pressure 8bar, 50 ltr
412ltr/min, (14.6 cfm approx) 3hp


the 2 compressors feed a 50 ltr receiver, I have both compressors giving 8 bar.

FAD quoted for these compressors is believed to be 9 cfm each....

So I assume I have 200 ltr of air at 8 bar and 18 cfm FAD.


from the 50 ltr receiver I have about 3 metre of 15mm copper pipe, then a 3 stage filter, from the filters I have a 5 metre hose which connects to my airfed mask belt.


with an inline regulator after the 3 stage filtration, line closed it reads just under 8 bar, if I attach the mask and gun, the mask works fine until I pull the trigger and the gun feels under pressure and the air to the mask feels like it has stopped.

the inline regulator at this point is showing pressure of less than 1 bar.



this is where I am up to and i don't know where to look next, I imagine i have a restriction somewhere which will allow pressure to build up and pass through but not at a decent rate so that the flow pressure is effected


Hope this makes sense to someone, hope that someone can help me out..

Dave

 

[brightspark]

does your 3 stage filter run at full tank pressure u say u have a regulator after the filter. surely u would need 2 regulators one for the gun and one for the air fed mask as they would run at diffrent pressures ??

 

[m5dkw82]

The regulator after 3 stage was added purely to check the pressure as my 3 stage does not have a display.


From my receiver tank I have 8 bar going to the 3 stage

the belt to go with the mask has a Y connector so that the gun has its own unregulated feed the belt has a carbon filter in it which regulates the air flow to the visor at 1 bar


if I put an adjustable inline regulator just before the gun it says it has 7 bar but when I pull the trigger I have a burst of pressure and then the flow pressure is very low

 

[brightspark]

The regulator after 3 stage was added purely to check the pressure as my 3 stage does not have a display.


From my receiver tank I have 8 bar going to the 3 stage

the belt to go with the mask has a Y connector so that the gun has its own unregulated feed the belt has a carbon filter in it which regulates the air flow to the visor at 1 bar


if I put an adjustable inline regulator just before the gun it says it has 7 bar but when I pull the trigger I have a burst of pressure and then the flow pressure is very low

well its bound to drop when u pull the trigger its not going to stop at 7 bar it will drop

 

[m5dkw82]

Yeah but not down to a flow pressure of less than 1 bar at the gun

the belt whistle also kicks in and that is pre set at 1 bar max.

 

[brightspark]

bypass the filter then see if your loosing the volume there

 

[eil]

What bore is the 5m airline that you are using

 

[carbon]

What mask are you using? If its sperian / Honeywell etc. then quoted air requirement for this is approx. 260l/min, 9cfm so will have a big impact on air requirement. Not sure how the devilbiss mpv 623 only needs 140l/min as its much the same as the sperian etc.

 

[m5dkw82]

What bore is the 5m airline that you are using

Ah... I actually don't know

if the bore is too small then you may have just found the problem for me

What mask are you using? If its sperian / Honeywell etc. then quoted air requirement for this is approx. 260l/min, 9cfm so will have a big impact on air requirement. Not sure how the devilbiss mpv 623 only needs 140l/min as its much the same as the sperian etc.

mask is DeVilbiss PROV-600

• Supply pressure: 4.0 bar (60psi) min to 7.0 bar (100psi) max
• Air flow rate: 1287-160 L/min (4.5-5.7 cfm)

 

[eil]

You will need a 3/8 or 10mm bore at the very least.

 

[m5dkw82]

I believe industry standard is around 8mm

am going to get a new hose, 1/4 bsp 5m with 10mm ID / 18mm OD

 

[m5dkw82]

my current hose is 1/4 bsp but I think the ID is small

 

[carbon]

If you just connect the mask and run one compressor does it run for a while then stop or is it constantly pumping

 

[m5dkw82]

I would have to check

I run my compressors till they fill, so 200 ltr of air at 8 bar

Then start what ever job it is I am doing

will do some time trials and post the results.

 

[carbon]

Can you connect the mask connector directly to the output from the regulator and try using the gun then. If that helps then it would suggest the hose is some of the problem.
If you are using standard pcl couplings to connect at the regulator, I found these to not allow sufficient air flow when using a mask and spray gun on the same air line.

 

[m5dkw82]

I swapped all my standard pcl couplings for high flow and I did notice a difference, I have ordered a new hose from draper which is 10mm ID

I will swap my fittings around and connect a Y connector to my 3 stage and try running the mask and gun, see what happens.


will try anything to get these to run off the same air line, really don't want two lines following me around

 

[m5dkw82]

I have done some basic tests today

I connected the mask direct to the compressors, individually

1st the warrior, 50 ltr pressure built up to 8 bar and regulator set at 5 bar, so the compressor fills up and I have all valves closed, I open the feed to the PROV-600 mask and air flows, after 23 seconds the pressure has dropped from 8 bar to around 5 bar and the compressor kicks in..... the mask is still drawing air, I think if i had left this flowing the compressor would have been running all day, it took about 5 minutes to built back up to 7 bar (cut out set at 8).

2nd the old clarke, 100 ltr pressure built up to 10 bar and set regulator at 5 bar, again allowed to fill up with valves closed, open the flow valve and it takes 1 min 15 sec before the compressor kicks in to refill, again this is chasing itself and prob wont ever fill up to cut out.


3rd test involves the clarke, I screwed the cut off down from 10 bar to 7 bar - filled her up and opened the flow valve, pressure now drops to 4.5 bar rather than 5 bar before firing up to refill, regulator still set at 5 bar it took 1 minute 15 seconds before the compressor kicked in and this time, she filled up to 7 bar taking 3 mins 25 seconds, then again 1 min 15 sec to drop back down again.



now here is the bit I have not got my head around yet........... is it a case of getting an air receiver and running the 100 ltr clarke into a similar or larger receiver ?
or is it a case of buying a BIG compressor

 

[Daz1968]

Find this strange as my clarke se16c100 when running just my mask set at 9 bar cutout runs mask for just over a minute before cutting in at 7 bar, then refills to 9 bar in about same time, so runs about 50% of the time I only use a devilbiss sri pro when using mask so just about get away with it for how long I spray. I also have a smaller 2hp one but this doesn't stand a chance with the mask.
I have compressor to regulator with hard pipes, followed by coalescing filter then carbon filter on belt, my hose is 8mm as recommended by devilbiss and a small regulator on my spraygun set to 2bar. As long as main regulator is set to 70psi or above the whistle never sounds. I am using high flow fittings on all connections as when I used normal pcl ones I did have pressure drop when spraying.

 

[m5dkw82]

My clarke is an old raider 120, it may differ from yours

I found if I set c/o switch to 8 bar it refills from 5 bar, when I dropped it to 7 bar the refill was 4.5 bar (not sure why the refill changed)


when my new 10mm hose arrives I will try the following

Both compressors set to cut out at 8 bar, feeding to the same pipe regulated to 5 bar then direct to the mask - although I may get a bit longer before they start up I know the warrior is going to run constantly

 

[carbon]

It seems like your warrior compressor fad isn't as the specifications of 9 cfm and it is causing you some problems. Adding a bigger receiver wont help after both compressors start running when you start spraying