reduce speed of air compressor pump?

[fordbroncodave]

I have a 60 gallon industrial air air compressor that is kind of noisy and seems to run pretty fast. I want to know if I can put a larger pulley on the pump to make it turn slower and quiet it down a little and possibly add life to it.

it currently takes 7 minutes exactly to fill the tank to 155psi

I see all these companies advertise low RPM pumps for longevity but can any pump be reduced by adding a larger pulley?

 

[CNGsaves]

Brand, pictures, details ??

You go in to AutoZone and say you need a waterpump for WHITE car??

 

[larry_g]

Depending on the pump the answer is a firm maybe. As cng says ya gotta know what the pump is and what the specs are for it. Most have a minimum speed to keep the oiling system working.

lg
no neat sig line

 

[fordbroncodave]

60 gallon industrial air. industrial air is the brand name. black with a silver decal

2 cylinder pump, not the weird looking 3 cylinder one.

looks like a morgan series, sanborn, coleman...

 

[fordbroncodave]

same as this. not my video

 

[larry_g]

What you need to do is search out the pump specs. With what little information given it's impossible to tell you what the answer is. Maybe a call to the mfg will lead you to the information you seek. A lot of mfg's use t he same pump on different compressors and just change the HP of the motor and the speed of the pump. If you have a small motor running the pump as slow as it goes then your out of luck. If you have a big motor running the pump at max speed then you can slow it down.

lg
no neat sig line

 

[unslow1]

Brand, pictures, details ??

You go in to AutoZone and say you need a waterpump for WHITE car??

I've seen people do that.

 

[zkling]

Not a good idea with one of those. Best thing to do would be to reduce your cut out pressure down to something like 125psi.

And BTW, that guys video. Talk about a accident waiting to happen. Pressurized pipe joints not supported under high bending loads.

 

[kams1973]

I don't think reducing the cut out pressure will reduce the noise much. I have a compressor with the same pump, and I made a modification to the air intake system. There is a thread floating around with the same modification. It does help some.
If you are determined to reduce the speed of the pump, you need to reduce the pulley size on the electric motor not the pump. Also, this pump runs very hot. This is due to the pump being a single stage pump and the cut out pressure being 150psi. The manufacturer recommends synthetic oil.

 

[zkling]

I don't think reducing the cut out pressure will reduce the noise much.

It will improve everything but cycle off time. The problem with those pumps, is like you said, they are single stage pumps being over driven to 150+psi. If you plotted tank pressure vs fill time, you would see a drastic level off ~130psi, where efficiency just tanks. From there you are just creating heat, noise and extra wear on the pump.

Decreasing pulley size on motor and or increasing pulley size on pump will have the same result. You will have to be careful with how much belt wrap you will give up by changing pulley diameters though.

Unlike the larger industrial pumps that are designed to run a wide range of RPMs. That pump is just splash lubricated and has a pretty small window of operation RPM wise. Not to mention there is a break even point between pump RPM and temperature since the cooling fan is designed into the pumps pully/flywheel.

kams hit the nail on the head, typically when people try to quite those compressors down the intake is the place to start. Hopefully he will post some pics and or details that will help you.

 

[kams1973]

I didn't find the thread I mentioned earlier, but I did find another one that discusses the issue.

http://www.garagejournal.com/forum/showthread.php?t=189471

Here's a couple pictures of the modification I did to my pump. There's another member on this board that went all out and plumbed in 2 filters. IIRC he was even making the plates to perform this mod for other members.

 

[cinco]

Working with the numbers you posted, it appears that your current setup produces about 12cfm - any attempt to significantly slow down the pump will also significantly reduce the compressor's output and the scale would probably be close to linear (slowing it to half-speed would likely produce half the cfm at that pressure). Depending on the sort of things you do with your air that may be just fine, but you'd want to carefully evaluate your requirements before going down that road. As others have said, an intake silencer is probably the way to go.

 

[fordbroncodave]

I should just start looking for an old 40 or 60 gallon horizontal compressor to put under a work bench. something built well and runs cool.

 

[fordbroncodave]

I went from a craftsman professional 60 gallon 2 cylinder oilless drive pump to this 2 cylinder oiled pump, I thought that was a huge step up considering I didn't even amount 10 working hours on the craftsman before replacing 2 cylinder sets.

 

[Mr onetwo]

Since your pump is splash lubricated you MUST not reduce the RPM too much or you will blow the pump in short order.If you can't get the min/max rpm ratings for your exact pump, I wouldn't touch it.For instance, my Sanborn B6000 2 stage can run from 745 to 1410 rpm without trouble.That pump doesn't look like any Sanborn I have ever seen.