PTO Air Compresser

[Brad_Blazer]

Nice work. I like the protective frame. It should lend itself nicely to adding some simple guarding.

I have one of those HF compressors in my home shop running off a 3hp motor at reduced RPM. It's been in service at least a couple of years now and it works great. Within reasonable limits the output should be proportional to RPM. Strangely, those floating ball flow meters are called rotameters.

Rotameters, Basic Flowmeter Principles

Is there a check valve built into the unloader? That could be a source of noise as the pressure gets higher. I started out with a plain swing check on mine and it was noisy above 100psi.

 

[srjones]

Nice work. I like the protective frame. It should lend itself nicely to adding some simple guarding.

I have one of those HF compressors in my home shop running off a 3hp motor at reduced RPM. It's been in service at least a couple of years now and it works great. Within reasonable limits the output should be proportional to RPM. Strangely, those floating ball flow meters are called rotameters.

Rotameters, Basic Flowmeter Principles

Is there a check valve built into the unloader? That could be a source of noise as the pressure gets higher. I started out with a plain swing check on mine and it was noisy above 100psi.

Thanks Brad. That's good reminder on the safety aspect. If I can't find/borrow a rotameter, I've found a simple method to calculate CFM by using a stopwatch and looking at the pressure gauge. Since the tank is of a known volume, CFM can be calculated as volume over time.

Here's a good write-up on the subject. Evaluating True Horsepower and CFM Ratings of Air Compressors

The unloader has a built-in check valve and I'll pay closer to it on the next run. That makes a lot of sense and I'm hoping that's it.

 

[srjones]

looks good to me!

soundguy

The more I look at it, the better it's starting to look to me!

 

[srjones]

The unloader has a built-in check valve and I'll pay closer to it on the next run. That makes a lot of sense and I'm hoping that's it.

Update 6/3/09.

It's not the unloader making the noise. My next suspect is the PTO telescoping shaft. When I took it off, I noticed there was play in the shaft, and the 'clanking' noise was similar (but much softer).

It needs to be greased, so I'll do that and see if it make a difference.

Any other suggestions out there for ways to eliminate PTO shaft noise? Would a few strategically placed hammer dents tighten it up a bit?

BTW, the PTO shaft is a Eurocardan so it's got that unique shape.

 

[Soundguy]

any ujoint play?

soundguy

 

[srjones]

any ujoint play?

soundguy

I checked that, and it seemed pretty tight. But they'll get a good shot of grease tonight to be sure.

 

[have_blue]

I checked that, and it seemed pretty tight. But they'll get a good shot of grease tonight to be sure.

How straight of a shot is the drive shaft? If it's on an angle greater than ~15 Deg, it may be noisy and inefficient.

 

[DieselPower]

How straight of a shot is the drive shaft? If it's on an angle greater than ~15 Deg, it may be noisy and inefficient.

They also don't like being run at 0 Deg either. They need to have a slight drive line angle or the needle bearings within the U-Joint caps will not spin. This leads to premature U-Joint failure due to flat spots on the needle bearings.