from an old post of mine,
I made this up for someone and thought it would be good to post, I know its kind of cheesey but oh well
Edit: adding additional comments as I think of them LOL
* bladder tank must be isolated from system during brine ratio measurements
* hydraulically operated automatic shut off valves will typically shut off the inlet to the membrane when the outlet pressure reaches 60% of inlet pressure
* In a real world system getting 85% of rated flow is about the maximum attainable**
* at 85% a 100gpd system should produce about 7.5oz/minute (bladder isolated)
* In bladder tank systems, membrane efficiency drops proportionally as the bladder tank fills. This is due to backpressure on the membrane outlet.***
** inlet pressure, water temperature and TDS will have a major effect on membrane output
(TFC membranes are usually rated at 77 degrees Fahrenheit @60psig and for every 1 degree drop, production drops 1.4% (57f water would reduce efficiency by 28%))
*** This drop in efficiency can be prevented by the use of a permeate pump and 90% automatic shut off valve. The permeate pump isolates the membrane from this build up in back pressure. Since the pressure differential across the membrane now remains constant, membrane efficiency also remains constant resulting in greatly improved recovery rates. This isolation also allows us to replace the 60% ASO valve with a 90% ASO thereby utilizing more of the bladder capacity and increasing output pressure. These modifications will result in a 60-80% drop in water consumption and brine output. In addition, this drop in water consumption also results in a proportional increase in prefilter life. A nice, simple and fairly inexpensive mod for any system using a bladder accumulator tank.
is all that clear as mud?