Best way to inject chemical in pressure fed pump
- Thread starter waright
- Start date
Jeff_L
Well-known member
Not sure how you'd do it on the outlet side of a pump running 1000+ psi. I go through the inlet, either with zero pressure regulator or floret. I have washes set up both ways. And both have their pros and cons.
I use a Generant regulator on the inlet side of the pump to lower the incoming water pressure and a DEMA 203C injector downstream of the regulator, been doing that way for well over 30 years with very few problems. I’ve worked on equipment that used a Zero Pressure Regulator and found them to not last as long as the Generant regulator. By pressure feeding the pump with water you'll have almost no problems with head washout and the pump seals last a lot longer because the pump isn't working as hard trying to suck water.
GoBuckeyes
Self-Serve and Automatics
All of our washes are pressure fed with the exception of one. I actually prefer the gravity feed set up as it is the most trouble free. Our psi fed setups use a Generant regulator followed by a large injector to which the soap and wax solenoids are attached. By adjusting the regulator psi you can greatly change the flow of wax and soap as seen on our flow meters. I'm not sure why but the regulators always seem to need adjustment to maintain the correct soap/wax flow. I've mulled around switching some of these setups to gravity feed but it would actually be a lot of work. Has anyone had success with eliminating the regulator and somehow psi feeding the wax/soap? I'm looking for the least complicated way to keep the system pressure fed while eliminating the most troublesome component (regulator). Thanks
We must be live’n right. We’ve had very few problems with the city water fed system or the Generant regulators over the years. We never have to readjust them, pretty much just set them up and forget them. We have had to replace the orifices in the DEMA 203 injectors once, they had gotten pretty worn. We’ve converted a few gravity fed systems over to pressure fed with excellent results.
MEP001
Well-known member
I've wanted to experiment with a Dosatron or DEMA Mix-Rite pump to inject soap and wax into city pressure water feed to the pump, but I haven't wanted to spend some $300 on a pump just to try it.
GoBuckeyes
Self-Serve and Automatics
Randy how are you setting your regulators? Do you set them to a specific psi. If you could, can you post a pic of your injector set up? If its easier, PM me and I'll give you my cell phone # to text pics to.
Thanks
getnbusy
Active member
an old southern pride unit is set up like this....
-you have 3 gravity feed tanks. rinse, soap, wax.
-there is a solenoid for each bay on soap and wax. a 1/4 line is plumbed from the solenoid into the rinse water line for each respective pump.
-when soap or wax is selected, the valve opens and soap or wax is sucked in with rinse water and runs thru the pump.
this setup is extremely simple. you can set it up and forget about it for the next 30 years unless a coil goes bad or you have a small leak.
-you have 3 gravity feed tanks. rinse, soap, wax.
-there is a solenoid for each bay on soap and wax. a 1/4 line is plumbed from the solenoid into the rinse water line for each respective pump.
-when soap or wax is selected, the valve opens and soap or wax is sucked in with rinse water and runs thru the pump.
this setup is extremely simple. you can set it up and forget about it for the next 30 years unless a coil goes bad or you have a small leak.
getnbusy agreed the best setup in a carwash is as you described with tanks. keep in mind, what you described involves buying 3 tanks, a float valve, 2 hydrominders, checkvalves, ball valves, solenoids. Also, the hot water tank cools off in between uses, so throw in a tank heater element, which requires another 15-20 amp breaker and is inefficiently keeping the water hot, or put in a small recirculation pump to reheat the water in the tank when it cools. another 15-20 amp breaker, pump, and extra plumbing.
The expenses with pressure feed are: solenoids, water regulator and 203 dema, or solenoids and zero pressure valve.
For the record, I don't like the pressure fed systems, however I find a lot of these setups in customer's washes. Thanks to all who responded.
The expenses with pressure feed are: solenoids, water regulator and 203 dema, or solenoids and zero pressure valve.
For the record, I don't like the pressure fed systems, however I find a lot of these setups in customer's washes. Thanks to all who responded.
getnbusy
Active member
yes gravity is a lot of components. I have zero experience with a pressure fed system but I have agreed to buy a carwash with that type of setup. Nice thread. good info that I will be needing soon
I don't have the same experience with the hot float tank cooling down. When I made my new hot water float tank, (It holds about 10 gallons) I designed a heat exchanger, purchased a t-stat, and SS circulator...One of the experienced members on the forum (Cantbreak80) told me I was wasting $$$ and energy with trying to implement this idea...I'm glad I listened to him! All I did was wrap the hot water float tank with aluminum foil faced bubble wrap insulation that they sell at Lowes or HD....Even after 12-16 hours of no use, the tank lid is still warm to the touch. When its cold out, the HP hose feels warm even on the first use of the day...IMHO, you can scratch all those components as they are not necessary.
https://www.lowes.com/pd/Reflectix-50-sq-ft-Reflective-Roll-Insulation-24-in-W-x-25-ft-L/3011904
you can also size the rinse tank as small as possible, as long as the fill valve and water pressure can keep up. Ive seen some setups with a rinse tank about the size of a gallon jug (for one pump). This allows the hot water to get to the gun faster.
getnbusy
Active member
Ok guys i got my hands on the pressure fed site i was speaking of in a prior post. Pressure fed sucks (literally and figuratively). On this D/H system there is a solenoid , a pressure regulator, then a dema for hi pressure soap. It sounds nice but the problem i am seeing is that you have to starve the pump to make the dema suck the chemical. Therefore the pump is loud as all get out. The old maintenace tech told me that "for some reason these pumps need seals all the time". Im guessing thats because the pump aint gettin enuf water. gee whiz. So now i have a 6 bay D/H unit for sale and Im lookin for a gravity fed system. Not saying the pressure fed cant be made to work, I just dont like it and im goin with what i know. In case anyone cares lol. ANybody lovin the pressure fed setup message me and i'll make you a deal
getnbusy
Active member
MEP is that for me
no sir. soap tank but no water tank with float valve. Wax is low pressure on this machine
no sir. soap tank but no water tank with float valve. Wax is low pressure on this machine
MEP001
Well-known member
Yes it was.
I'd suggest either adding a float tank or zero pressure regulators. If you use liquid soap, you might try a Dosatron or DEMA Mix-Rite pump that uses water flow/pressure to draw chemical. I've been told that just plumbing city pressure to the injector pump and then to the soap solenoids works. I have yet to see something like that in operation.
