Vacuum System Filters

[bmckearney]

I'm in the of putting together a vacuum system for turning and I'm wondering about filters. I have a new Gast oil-less vacuum on order along with a needle valve. From the research that I've done it sounds like I should have two filters - one closest to the lathe and one next to the bleeder valve.

Do I need to order a specific vacuum filter, or can I use a simple compressed air filter such as one available from some place like Home Depot? Such as this one: http://www.homedepot.com/buy/tools-hardware/air-compressors-tools-accessories/husky/1-4-in-air-compressor-filter-61421.html

Would there be any problems with using a compressed air filter in a vacuum system? Any reason why this wouldn't work?

Thanks in advance for any advice and recommendations.

Brian

 

[Mike Peace]

For the bleeder valve air inlet I used a Fram G2 fuel filter from Wal-Mart for less than $4. It comes with a 1/4" rubber hose that will slide right on to the brass barb. My Gast 523 has built in filters for the inlet and outlets on the pump that can be removed and cleaned with an air hose.

 

[Dale Bright]

You can find the information you need for filters here: http://www.sawmillcreek.org/showthread.php?84279-Vacuum-Chuck-System-–-How-I-Built-Mine

 

[Vernon Oberle]

info on vacuum systems

Go to www.joewoodworker.com for a very complete treastice on both vacuum systems for turning and clamping. They also have all the parts and filters needed.

Vernon

 

[Bill Boehme]

One filter on the pump side of the manifold where you mount the gauge and bleed valve is sufficient. You can get a needle valve with an integral small sintered metal filter on the open side which would be ideal for keeping dust out of the tiny opening. Don't forget that you also need two additional valves. Check with you Gast owners manual for the cool down procedure to see how to use the two additional ball valves -- one for blocked port and the other for opening directly to atmospheric pressure -- I mounted mine on a T fitting right at the intake port of the pump. My observation is that many woodturners spend a lot of money for their vacuum pumps and then neglect them -- apparently never peeping at the manual.

 

[Frank Mussenden]

Air Filter for Vacuum Chuck System

Try the Surplus Center $5.99 plus shipping
AIR FILTER
Donaldson plastic housing air filter. Removed from new vacuum pumps. Spin on clear bowl for easy element checking.
Item# 4-1565
SPECIFICATIONS35 PSI max
1/2" hose barb on inlet port
1/4" NPT outlet
3-3/4" dia x 6-1/8"
Shpg 1 lb

 

[BrianMcKearney]

Shutdown Procedure...

I'm aware of the shutdown procedure and was thinking that one ball valve near the tubing going to the lathe would be sufficient? My thinking is that I could shut the bleeder valve AND this ball valve to close off the system, and just open the ball valve without connecting to the lathe to open the pump to atmospheric pressure - restricted only by flow through the filter.

Anyone see any problem with this? Seems like even during the shutdown procedure, it would be nice to filter the air going through the pump.

 

[Quinn McCarthy]

Take vernons advice and go to the Joe woodworker sight. It is a great place to start. I built one of Joe's vacuum pump kits that I use for clamping. He has the plans and parts out there for a vacuum chuck setup. Haven't bought that yet. Hopefully soon.

Hope that helps.

Quinn

 

[AlanZ]

Bill,

You mentioned

"My observation is that many woodturners spend a lot of money for their vacuum pumps and then neglect them -- apparently never peeping at the manual."

I have a couple of Gast 0522 vacuum pumps.
I just double checked the 22 Series Oil-Less Vacuum Pumps & Compressors Operation & Maintenance Manual (PART NO. 70 - 270 G370PL (REV-C))

I see no special instructions for startup or shutdown.

Do you know of any recommended procedures? Are they particular to specific types of pumps? Perhaps oil-less rotary vane pumps are not prone to problems with simple shut down.

Considering that these pumps are often turned on and off by vacuum controllers (to maintain vacuum levels in things like veneering bags), that supply current or turn off the current as needed based on preset values, I don't see where there's a chance to do anything other than essentially flipping the switch.

Thanks in advance for your thoughts.

 

[Mark Levitski]

The shutdown procedures must only apply to certain models. I have a Gast M450X oiless piston vacuum pump that was taken from an abandoned sewer lift station that I was responsible for maintenance on. It never had a shutdown other than on to off, despite being a part of an intricate and automated control assembly for the lift station. In its original capacity it ran for years on end and never failed or required repair this way. After being salvaged it's been used for a couple years for my lathe work.

 

[BrianMcKearney]

I purchased a Gast 0523 new from Craft Supplies USA - this is a 1/4 HP model.

According to the owner's manual, the Shutdown Procedure is as follows:

"It is your responsibility to follow proper shutdown procedures to prevent product damage. NEVER ADD OIL TO THIS OIL-LESS PUMP.

1. Disconnect plumbing.
2. Operate product for at least five minutes without plumbing.
3. Run at maximum vacuum for 10-15 minutes.
4. Repeat step 2.
5. Disconnect power supply.
6. Plug open ports to prevent dirt or other contaminants from entering product."

 

[AlanZ]

That sounds truly odd. According to those instructions, it takes 20 to 25 minutes to shut down the pump.

 

[AlanZ]

I found a little more information...

The Gast 22 series manual doesn't mention a shutdown procedure.
The Gast 23 series manual shows exactly what Brian posted
The Gast 40 series manual adds some detail:

Proper shutdown procedures must be followed to prevent pump damage. Failure to do so may result in premature pump failure. The Gast Manufacturing Rotary Vane Oil-Less Vacuum Pumps and Compressors are constructed of ferrous metals or aluminum which are subject to rust and corrosion when pumping condensable vapors such as water. Follow the steps below to assure correct storage and shutdown between operating periods
1. Disconnect plumbing.
2. Operate product for at....

So it appears that they are concerned about corrosion when working with vapors. This is not the use case that we're dealing with in our vacuum chucking, so I think it's safe to simply toggle the power.

 

[john wallace]

I found a little more information...

So it appears that they are concerned about corrosion when working with vapors. This is not the use case that we're dealing with in our vacuum chucking, so I think it's safe to simply toggle the power.

Bingo, the procedure is the same that I used when working with very nasty gases. I am using a pump that's probably 30 years old and the only precaution I take is to change both filter elements once a year.

 

[davidwalser]

...
So it appears that they are concerned about corrosion when working with vapors. This is not the use case that we're dealing with in our vacuum chucking, so I think it's safe to simply toggle the power.

Ummm, won't the moisture in a block of wood be converted to vapor (mostly water vapor) when it is drawn out by the vacuum? And, won't that vapor along with the hummidity in the air that's inside the vacuum chuck and the vacuum lines be drawn into the pump (where it can condense and cause corrosion)?

 

[Mark Levitski]

I wonder what woodturning suppliers like Craft Supplies are doing selling a pump that takes that long to shut down each time? Are other models that don't require this just too expensive for the average turner?

My sewer lift station Gast pump runs warm and has an exhaust, so I don't think condensation is a big issue. In its previous life it drew air from the wet well (water vapor as well as nasty gases) and, except for a ping-pong ball float valve that prevented actual liquids from getting into the pump, it had no controls except for threshold on/off settings. Sometimes it ran momentarily, but a lot of times it took a while to lift the water up out of the wet well and into the big impeller pump. Must be a totally different design?

 

[AlanZ]

David,

My guess is that it would take a Gast pump all of about 5 seconds to exhaust any accumulated vapor from a piece of wood.

So simply opening the relief valve and then shutting down the pump would seem (to me at least) to be more than sufficient.

If anyone wants to follow the supplied instructions, go right ahead. But I'll freely admit that each time I dismount a bowl from a vacuum chuck and need to turn off the pump, I'm not going through a 25 minute procedure.

 

[John Giem]

Remember that the only reason for having a filter is to protect the pump. A filter must be before the pump, filters else where can be helpful but not needed. I know of one turner that regularly mounts green wood using vacuum and put a water trap in his system to catch liquid sucked out of the wood.
John

 

[davidwalser]

...

If anyone wants to follow the supplied instructions, go right ahead. But I'll freely admit that each time I dismount a bowl from a vacuum chuck and need to turn off the pump, I'm not going through a 25 minute procedure.

Alan,

I agree with you. I think Gast's instructions are more CYA than anything else.

My point was that Gast's instructions don't limit their recommended shut down procedures to just when the pump is used around the vapors coming from industrial chemicals. They specifically state the shut down procedures should be used when the pump is used with water vapor. Given that the air around us, on average, is 1% to 4% water vapor, the instructions apply to our use of the pumps in our shops. For a variety of reasons, I believe that the shut down procedures are overkill for most of us -- but that doesn't mean Gast hasn't given themselves an out if a pump should fail while under warranty.