need help w compressor regulator choice

[Piper]

So I'm totally stoked. I just bought this compressor http://oemproamtools.com/rkcomp/df580.htm in the upright (vertical) version. The discharge side of the tank currently has a .98" threaded hole. So, I'm not 100% sure what pipe thread that is called. I need to select a regulator for this compressor and don't want to pick one that is too small and therefore becoming a bottle neck for air leaving the tank. I have a cabinet and syphon sand blaster and need a lot of air to run both these tools. The store where I've purchased the compressor sells Lincoln regulators and the guy has suggested the 1/2" model #600008 which is on page 50 of this link http://www.lincolnindustrial.com/Catalogs/_English/00-MAIN_Catalogs/General_Lubrication.pdf

Can you guys look at this and see what you think? I don't want to use too small a regulator and become a bottle neck but if the 1/2" one is ok it's less than 1/2 the cost of the 3/4" one. I know that pipe tap and pipe size are different so that's why I'm wondering what is the most appropriate regulator to choose for mounting on the tank.

Piper

 

[logical]

I assume that's 1 inch pipe but I'll leave that to the experts here.

I bought all my filters and regulators from this Ebay seller who has a ton of discontinued good quality stuff from a company I think Parker bought out. Dirt cheap. I have this 3/4 regulator. Be a little careful because a few of his other auctions are for regulators with a 60 psi max or built in check valves....but this one has neither. Oh wait, just realized it maxes out at 150 psi max in and you have a monster that puts out 175...maybe somebody else can use them or maybe he has something for you.

http://cgi.ebay.com/Taiyo-UMRV-20-3...photoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

Not to come across as the total Ebay slappy that I am but for oddball stuff like a 3/4 regulator it is the place to go. All sorts of surplus industrial stuff is there and cheap. this one would be perfect for your new set-up:

http://cgi.ebay.com/WILKERSON-3-4-A...8530685QQcmdZViewItem?_trksid=p3286.m20.l1116

 

[SteveU]

I wouldn't put a filter/regulator on your air tank, the water vapor will pass right thru it and condense somewhere in between it and your air tools which will be bad for them. Best place for this is at the end of at least 25' of hardline & right before your hose or hose reel. I went with a 3/4" on mine & am happy with it. Figured like you I didn't want any bottlenecks so went with 1" hose connected to 1" black pipe then reduced down to 3/4" right before the filter/regulator which feeds 3/8" hose with type V HVLP fittings, has no problem getting enough air thru this to run a 3/4" CP impact, die grinder, cutoff, 6" DA sander, etc. I got my regulator from Eaton compressor, think I paid 80.00 for it.

 

[logical]

I regulate down to 100 psi within a few feet of my tank but I have a filter/water separator just before it to keep any junk from fouling the regulator.

 

[Torque1st]

A regulator wastes the energy that was used to compress the air. Don't use one unless you have to for some very pressure sensitive application. Set your pressure switch to cut in and out around the pressure required. If you need 90PSI at the blaster set your pressure switch to cut in at 100PSI (or whatever is required due to pressure drop in the line) and cut out as soon as you can. Some pressure switches have a differential setting.

Some compressors are very good for high volume applications and have unloader valve setups. The motor runs continuously. My compressor runs both ways at the flip of a switch.

 

[daw53]

Piper,

First off, congrats on the new compressor, looks like a nice unit that will last a lifetime with proper care.

In regards to the of the out fitting size, it sounds like it is probably 3/4" nominal pipe size. See the attached link, (which is just the first one that I found).
http://www.plumbingsupply.com/info-pipesizes.html

As to the size of the regulator, the 1/2" Lincoln one that you talked about is most likely more than adequate for the 20cfm of your compressor. Unfortunately, Lincoln does not list the cfm ratings of their FRL equipment in the catalog link that you posted. However, I happen to have a Norgren catalog handy and they list flows about 120-200 cfm for various 1/2" regulator models.

Also, I have a different opinion than Torque1st regarding a regulator wasting energy. While it is technically true that there may be a small energy loss, I feel that in this case (and probably in most cases), overall you are better to set the tank pressure hihger and regulate it down what you need. By setting the pressure switch lower than the compressor's capability, you would be causing the compressor to cycle more often. This could cause more start up wear and also more power usage, due to the inrush current in starting the motor.

Again, congrats on the new addition to the shop!

- David

 

[Torque1st]

Also, I have a different opinion than Torque1st regarding a regulator wasting energy. While it is technically true that there may be a small energy loss, I feel that in this case (and probably in most cases), overall you are better to set the tank pressure hihger and regulate it down what you need. By setting the pressure switch lower than the compressor's capability, you would be causing the compressor to cycle more often. This could cause more start up wear and also more power usage, due to the inrush current in starting the motor.
- David

HP loss thru a regulator is straight forward and well documented in technical literature. Guessing about technical aspects like startup power usage or compressor capability is ridiculous.
The more air you use and the bigger the pressure drop the more power you waste. A small tool may not waste much but a large abrasive blaster will waste many dollars. Most people do not know about the dollars being wasted in an air system because they can not see or feel them them and have no idea what it costs to compress air to a given pressure. The wasted dollars mount up hour after hour when the system is in operation.


From Engineering literature:
---------------------------------------
Horsepower is wasted by reducing the pressure through a regulator. This wasted power can be estimated by using the following formula:

[ (HPF@RIP) - (HPF@ROP) ] x SCFM = HP waste

Where:
RIP= Regulator Inlet Pressure
ROP= Regulator Outlet Pressure
SCFM = Tool air consumption

Examples:
Single stage compressor, 30PSI drop;
RIP= 100;
ROP= 70;
SCFM= 4;
[ .179 - .148 ] x 4 = .124 HP (92W)

2-stage compressor, 90PSI drop;
RIP= 180;
ROP= 90;
SCFM= 10;
[ .211 - .156] x 10 = .55 HP (410W)

Table:
HPF (Horse Power Factor):
-----------------------
psi___HPF 1-stage__2-stage
-------------------------
40_____ .107_____---
60_____ .136_____.128
70_____ .148_____.138
90_____ .170_____.156
100____ .179_____.164
120_____.196_____.178
140____ .211_____.190
160_____.225_____.201
180_____.239_____.211

Anyone that wants to get into how these formulas and factors were derived see the Machinery's Handbook.

NOTE:
The Watt conversions are direct (1 HP= 745.6998715823 W) and do not take into consideration the lower efficiencies of motors as they get smaller:

Single Phase Alternating Current Motors Full Load Current in Amperes:
---------------------------
HP____ 115V___230V
---------------------------
1_____ 16_____8
1.5___ 20_____10
2_____ 24_____12
3_____ 32_____16
5_____ 42_____21
7.5____ --_____33
10____ --_____44

You can see that efficiencies increase as motor size/HP increases.