2-man rig questions

I have a new 8gpm/3000psi 2-man rig that would like to:

a) have an unloader that relieves the "kick". On my 4gpm/3500 rig, I am using a K5 and love it. As I understand it, a flow unloader won't work on a 2-man rig, but there is another (not pressure) type?

b) limit the volume to 4 gpm from either gun. We usually downstream from one gun and run a surface cleaner on the other and run into flow issues as the chem tip is allowing more flow from the one gun.

There is another type of unloader, Pulse(?), that keeps a lower pressure in the hose when in bypass that, I hope, can be used. Also, its not that I can't downstream and run the surface cleaner, its that there is less oomph to spin it.

Any suggestions? Thanks,

John Orr

Hi, John. There are 3 types of unloaders: flow, trapped pressure, and regulating. You've probably got the large unloader with the green spring, right? That is a regulating unloader. You can use a trapped pressure unloader as a regulator, but they don't last. The only way I can think of to maintain line pressure for your surfacer is to use a very small injector on the one line to apply chemicals. That will basically act as the nozzle orifice for 4 gpm. But, with that injector in place, you'll never get 8 gpm through that particular line. It would be dedicated to 4 gpm operation.

Thanks Russ. Would a 2.1 injector be appropriate? and is there any way - even if it don't last - to use an unloader that doesn't "kick" me so much? (I have had one surgery on my shoulder this year and will be having another in a few weeks.)

A 1.4 orifice would be the equivalent to the 4.5 nozzle that makes 4 @ 3,000. The smallest injector I have access to is a 1.6, equal to a #6. However, I thought about the set up below to custom meter the water flow. You'd have to set it with a gauge on the surfacer and lock it down. You could actually mount it on qc's to make it more versatile for you.



ST-62 Variable Chemical Injector
Flow Orifice Adjusts for Machines from 2-8 GPM
*Forged brass body
*3500 psi max pressure
*8 GPM max flow
Requires ST-61 (below) to regulate Chemical Injection Rate.

ST-61 Chemical Metering Valve
*Snap-on attachment to ST-60, ST-62, ST-261/I
*Adjusts from Off to Full flow
*Glass-filled polyamide body & valve parts
*1/4" hose barb
*Teflon® seals
OR.....

ST-66 Chemical Meter & Selection Valve
*Two input barbs for different chemicals to single outlet barb
*Double metering dial with center OFF
*Panel mount in single 5/8" hole

General Pump has an unloader called a VB10, modified pressure unloader...drops system pressure to 400 psi or so. I'll have to call Monday and see if it's even feasable to try it as a 2 gun unloader...will have to get back to you on that one.

I'm willing to try just about anything! Let me know about the VB10.

Out of curiosity, would it be possible to have two unloaders? Install a "T" off of the pump, to an unloader. Then, have the smaller chem injector on on side, while leaving the other side alone, so that I could draw 8 gpm on that side - assuming one gun operation.

Here's what I got from GP. The ZK1 flow controlled unloader may work on a 2 gun system if the outlet valve is removed, basically turning it into a regulator. It's never been tried, so there are no assurances of success. You would have to install a flow switch to control the burner because a regulator will keep a constant load on the system and not allow a pressure switch to work.

The 2 unloader theory won't work at all. There'd be no way to set them up for different flows and ignore pressures. Sorry.

One last idea...we could put a 4,000 psi metering valve between the gun and the wand, that way you could "ramp up" the discharge after you squeeze the trigger. You would still want the trigger gun in place for safety in case you dropped it.

We're wading through uncharted territory here, but I'll help all I can.

Thanks Russ! Is removing the outlet valve a big deal? As far as the switch for the burner, my rig has both a flow and a pressure switch. Do you have a picture of a metering valve? Thanks again.

The outlet valve is just a piston and spring behind the outlet fitting. Here's a metering valve...same as a chemical valve.

Russ, can you set me up with a modified ZK1? I am willing to try it - I realize that there is no guaranty that it will work, but I have to stop the kick.

I can order one Monday, modify it, and probably have it out of here Wednesday or Thursday. List on it is $120.80. I can give a 35% discount on General parts, so your cost is $78.52. If this suits you, let me know, and I'll make it happen.

Russ,

That would be great. Please let me know a total and I can PayPal you or check or credit card. Thank you.

Hello John,

Here is a picture of our General. It is rated at 10.2 gpm.

We use a Baird by-pass relief valve as an unloader. It is shown on the right side of the picture. We dial up the pressure we want before opening the gun on the wand. We determine the flow by the size tip that we put into the wand.

The pump is pumping full flow all of the time and returns unused water back to the surge tank.

Dave Olson

Dave Olson said:

Hello John,

Here is a picture of our General. It is rated at 10.2 gpm.

We use a Baird by-pass relief valve as an unloader. It is shown on the right side of the picture. We dial up the pressure we want before opening the gun on the wand. We determine the flow by the size tip that we put into the wand.

The pump is pumping full flow all of the time and returns unused water back to the surge tank.

Dave Olson

Click to expand...

Hey Dave,

I'd like to find out more about the Baird by-pass. Does last longer than a regular unloader? Will it relieve line pressure or is there a kick when you pull the trigger? Where can you find them?

Thanks,

David

Hello David,

Here is a link that describes the type of valve we use. http://www.fredcgilbert.com/baird9000.pdf

We've had our current valve for many years. I think we paid about $400 for it and the repair kit costs about $150.

Dave Olson

Thanks Dave

Follow-up

Well, I was finally able to install the new unloader last week, but it didn't work. No pressure, everything was bypassing back to the tank. I called Russ (on a Sunday!) and we discussed what to do. We decided to re-install the valve (fortunately, Riuss had saved the parts) and see how that worked.

I re-installed the outlet valve and spring yesterday and it works! As a matter of fact, it works exactly as I wanted. No pressure in the hose until you pull the trigger, then a gradual build-up (just a second or two) to full pressure. It works with either gun. When one gun is in use and the other gun is opened, there is still a kick, not too bad, the same as before.

Thank you Russ.

Glad we got it straightened out, John....