Low pressure functions

[GregF]

How do you reduce the amount of time it takes for LP chemicals to get to each bay? We have some functions where it seems to take 10 to 20 seconds before we get a good steady spray.

 

[Plow Guy]

I still use the I.R pumps my pumping station came with. I have the air pressure set at 75 PSI. My low pressure chems switch at my boom. A couple years ago the High Performance Wash news letter suggested using a 1/4 hose from the boom to the gun. Minimal pressure loss, quicker chem response. It helps but some customers still will not pay for the lag time.My tire cleaner has air, my presoak does not, the air spitting out seems to pacify some. Some day I will switch my low pressure functions to a separate gun with the large tip. I think this will maximize foam, and increase response time.

 

[MEP001]

10 seconds isn't too bad; 20 is a lot. I use a PLC that blows down the bay hose after each wash, so it takes just 3-4 seconds for tire cleaner or presoak now. I also set the low-pressure features at 70-80 PSI, with only a small amount of air needed to make foam.

 

[Earl Weiss]

Need more info on your setup. Typical is to have the manifold with check valves just above the boom in the trough. That way the solution lines are full of the respective solution all the way to the boom. The only delay should be for the solution to travel through the boom to the gun. Is this what you have?

 

[mac]

10 seconds seems normal. A lot of the Ginsan setups that we work on take 15 to 18 no matter what we do to them.

 

[GregF]

Yes, Earl, we have D/H equipment, and I haven't seen the fitting we're using above each bay in any catalogs, so I assume it's theirs. We have 4 poly lines (i.e., air, presoak, T&E, & foam wax) "pushed" into this little manifold fitting, and then we have a check valve on the line beyond that before it connects to the main line.

 

[GregF]

MEP, I'm intrigued by your many uses of PLC. Where's the best place to learn more about that and how to implement it at our washes? Can you post some pics of some of your PLC setups? Also, can you make a list of all of the things you've used it for?

Thanks.

 

[MEP001]

I've written programs for a spot-free system controller (which included a flush at the end of each fill cycle, a low-pressure shutoff that can't short-cycle the pump and never needs a manual reset), a tri-color foam wax controller that creates six colors of foam cycling the three with an overlap, a combination shut-off for the in-bay credit card acceptor/bay hose purge/pump delay, a couple of lighting controls, a controller for the Doyle vacs to get rid of the awful mess of the 4-stack rotary switch, a boiler control that disables the boiler after a period of idle and starts it immediately when a customer drops a coin, a simple latching-circuit for a push button control, and a foam brush purge. I've put into use every program except the foam brush purge and the push button control.

You can get some ideas and a lot of help here:

https://www.automation.siemens.com/...Descending&ForumID=40&Language=en&PageIndex=1

 

[Jeff_L]

Greg, you didn't mention whether this was happening to one bay or all the bays. I'm assuming it's happening to all bays since you didn't specify. Have you taken off the check valve after the manifold above the bay to make sure it is operating okay? It might be cracking slow or even stuck open which would flood your LP lines when your HP is on. If so, when a customer uses a LP function, it would have to clear out all the water in the LP line.

One way to check it is to turn your HP function on, then go into your shop and see if any of your LP gauges are pegging out (meaning your check valve is open and you're feeding HP water back against them).

You may have checked all this out, however, sometimes it's the simplest things that we all forget!