Recirculating Valve?

[TunbridgeDave]

I'm still trying to figure out this old Sap Brother RO machine. It has a ball valve and an adjustment screw(looks like a fuel shutoff) on it that I don't know what it's for. It's positioned after the membranes in the concentrate output line and it goes back to the inlet of the high pressure pump. Does this mean if I open the valve during concentrating it will give me the recirculation loop that a separate recirculation pump would provide?

I asked Mike at Leader about it and he didn't know but suggested I send him a picture. So maybe I'll put one up here as well.

[maple connection]

Could it be for recirculating on a wash cycle?

[TunbridgeDave]

I don't know Kevin. All it does is take the concentrate from the membranes and brings it back to the hp pump again. Someone told me they thought it was a way to purge the air out of the system when starting the feed pump. Because with the valve open and just the feed pump on the sap would bypass the hp pump and membranes altogether.

[maple connection]

I worked with a turbo compact ro and it had a similar valve it was called the v 2 valve. The use of the valve was to adjust the membrane pressure. we would set the perm. and conc. were we wanted to run the machine at then we would open the v-2 valve to lower our membrane if to high 500+ pressure to still keep the same perm. and conc. flow. I hope you can understand what I am trying to say.

[maple connection]

We open the v-2 valve almost all the way on a wask cycle just leaving enough pressure on the pressure switch so the pumps stay running.

[TunbridgeDave]

I have a different valve for adjusting the system pressure. It's just a needle valve that restricts the concentrate coming out of the membranes. If I close it up enough it will actually stall the hp pump and the max pressure I can get is around 225psi. I open it up all the way when washing. I don't see how this other valve would relieve the pressure because it just directs sap back into the hp pump inlet. I guess I can try opening it while the machine is running and see what happens to the pressure. I really don't need to reduce the pressure but if it recirculates the sap through the membranes in the process that would be good I guess.

[maple connection]

I have 1 final idea, MP@C makes r.o.s by my house. They are a company that deals with machines for many diferent industrial companies. They started making sap r.o.s a few years back and they have a valve like you are talking about. There idea behind this valve is to recirculate the sap back threw the membrane as you are concentrating. Some people leave the valve closed to just do a single pass on the sap and some people open the valve to recurculate the conc. to raise the brix alittle higher on the conc. There is a thread started about mp@c you could talk to them and they could explain it to you in better detail. They are located in Edgar WI. Good Luck!!

[Parker]

I have an old sap brothers r.o. .Mine has a valve after the membranes that you partially shut to adjust the pressure on the system-set the flow-concentrate,,mine dose not flow back into the h.p pump (have to look agine to make 100% sure) a pic might help

[TunbridgeDave]

4754 I hope this works, first pic upload.

A = Hp pump inlet
B = Flow from hp pump to membranes.
C = Concentrate return line from membranes
D = Concentrate output line to concentrate(pressure) valve, flow meter, and storage tank.
E = To pressure guage
G & F = Valve abd adjustment needle in question.

Hopefully this will help

[Tom Cook]

The ball valve above the high pressure pump is for recirculating your concentrate. During wash and rinse you need to close the valve. The Parker needle valve is used to adjust your sugar content output of your concentrate.

[TunbridgeDave]

Thanks Tom for the info. I think there may still be some confusion. I have a separate concentrate (Parker) valve on the front panel of the machine that's not in the picture. So if the ball valve (F) and the small needle valve (G) are used for recirculation of the concentrate through the membranes, how do you know how far to open them? My guess is that you set the needle valve(G) to where you want it and then just use the ball valve(F) to switch back and forth from washing to concentrating.

[Tom Cook]

I think you got it correct. My Sap Brother does not have the G needle valve. I have the same feed pump as you have and I put a bypass valve before the sap filter because after a day with storage solution in the cast iron pump you get a lot of rust that forms. At the start of flushing the solution out I open the bypass valve and dump down the drain 5 to 10 gallons. This will keep the rust out of your cleaning filter. I got tired of the rust and replaced the feed pump this year with a stainless pump.