By splitting the feed flow the velocity will be reduced by one half and the pressure drop by an even greater amount since the pressure drop is proportional to the square of the flow. Feeding from both sides may be most economically feasible where the pressure is low enough to use plastic pipe. This option is shown in the picture below.
The membrane supplier can help with the the evaluation of membrane performance of your proposed system.When properly sized, use of multiport vessels to eliminate external manifolds will have little if any affect on overall system performance. However, as pressure drops are increased, systems that are already being operated close to the edge of recommended conditions may experience problems within one or more vessels. It is therefore recommended that worst case conditions be evaluated carefully in conjunction with your membrane supplier.
Even though the pressure drop across each vessel may be acceptable, the velocity of the water through each port must also be evaluated. It is suggested that the water velocity throughout the entire system be checked for proper velocity, however, the first connection from the feed source is typically where problems can occur. While the length of each feed port is very short, velocities in excess of 11 ft. per second should be avoided to help ensure proper system performance. We have included the published velocities for schedule 40 pipe on this page.
Do not assume, because a set of vessels can be manifolded together, that Codeline recommends or endorses such use in your particular application.Used properly, multi-porting with 3" and 4" ports opens up a whole new world of potential cost savings. With this opportunity comes a responsibility to carefully evaluate projected membrane performance. Codeline recommends that you work directly with your membrane supplier to obtain approval of your proposed design.