Solenoid valve choice

[copperglobe]

Need a solenoid valve for both NO and NC applications where the valves will work under almost zero water pressure. The application is installed on a water tank where the only pressure will be that pressure from the height of the water in the tank. I've tried some of the normal valves that we use at car washes but the pressure isn't enough to get a desirable flow out of the valves. Car Wash solenoid valves allow flow either from the pressure behind the valve of the vacuum produced by a pump or some other means. Ideas?

 

[BBE]

It's probably not the valve that's restricting the flow it's more likely the orifice size. Most are only a 1/8 orifice. That's just too small for gravity feed

 

[copperglobe]

Maybe I should explain further; I've got two foam brush soaps (water and methanol) one for above freezing and the other for below. I use a Procon pump for the foam brushes. Instead of ball valves to switch between the two soaps as temps go up and down I'd like to have solenoid valves (NO and NC) on the two soaps to feed the pump and run it through a thermostat and remote electrical device. Maybe the Procon can "suck" the soaps through normal NC and NO solenoid valves to feed enough to the pump without damage? Not that familiar with Procon.

 

[Randy]

You want to use a 3 way Erie valve https://www.kleen-ritecorp.com/p-1362-erie-3-way-solenoid-valve-12-24v-0-10psi.aspx to do the switch over. How do you purge the regular Foam brush soap out of the system when it switches over to the methanol mix?

 

[BBE]

Agreed, you're going to wind up with some overlap that will lead to foam brush freeze ups unless you just buy a purge system. There are plenty of purge systems already out there available created for exactly this. I have one at one of my self serves and it works pretty darn good.

What's going to happen is that your valve is going to switch over to the methanol once it hits 32 degrees, but what happens when it hits 32 degrees at 11pm at night, and then continues to drop and nobody uses the brushes to purge the summer soap out of them and put the methanol in then. Then you are going to have all frozen brushes in the morning.

 

[copperglobe]

My plan is to address the purge challenge with a timer. When we want methanol in the foam brushes all the bay's foam brushes turn on and purge for 18 seconds- the time to get methanol out to all brush heads. Methanol is blue in color versus warm soap of red. 18 seconds allows all bays to change from warm soap to methanol. How do I address when the temperature goes back and forth across the freezing threshold? I've got another timer that, once methanol is used, it locks it in for three hours and then the temperature is read again. That way it's not purging over and over if the temp is hovering around freezing. I'm sure that one of those simple PLC units would do it but that's not something I know how to program. Some day...

 

[MEP001]

Do you have two separate tanks and separate Hydrominders? If so, the Erie valve would IMO be your best option since it won't restrict flow to your pump even if it fails. Two DEMA A473P solenoids would also work, but it will be more expensive and potentially less reliable.

I've ordered the latest software to program Siemens programmable relays - once I get it I should be able to create a ladder program for it fairly easily to do what you want.

 

[copperglobe]

I do have two separate tanks with separate hydrominders. Those two tanks feed into the one Procon pump.

MEP001, I would love to learn the Siemens software as that's what is running my automatic PLC units- programmed by a brother. I just haven't taken the time myself to study them out. Even one of these seems like you could do a lot at a car wash:

https://www.automation24.com/logic-...TwXVA-WR1Hz58lKf0I2dIjWuyxSnMgdUaApqtEALw_wcB

 

[MEP001]

I do have two separate tanks with separate hydrominders. Those two tanks feed into the one Procon pump.

MEP001, I would love to learn the Siemens software as that's what is running my automatic PLC units- programmed by a brother. I just haven't taken the time myself to study them out. Even one of these seems like you could do a lot at a car wash:

https://www.automation24.com/logic-...TwXVA-WR1Hz58lKf0I2dIjWuyxSnMgdUaApqtEALw_wcB

Your link says logic module, but I don't think there's any "logic" to them at all. It does take a good bit of study to understand them and make things work, for example there's not a block you can just drop in and have an accumulating timer, you have to build it out of many blocks. I tried to make a 32-coin timer with one and very quickly ran out of memory. Logic relays are more versatile.