"HOLLOSEP®" high-pressure type HL is based on a hollow fiber configuration module that builds on the proven reliability of conventional Toyobo's RO module using cross-wound arrangement of CTA hollow fiber.
The outer diameter of hollow fiber is reduced and this allows a greater packing density that leads to increase in membrane area/unit volume as compared with conventional fiber dimension and greater production of water
In addition, HL is longer in length than HB series and builds on the new technology based on both open-ended (B.O.E.) hollow fiber structure vs. single open-ended hollow fiber structure. The both open-ended hollow fiber membrane structure allows reduction of pressure drop along hollow fiber bore that leads to greater product water flow.
This is a double element type. The pressure vessel contains 2 identical elements inside. The two hollow fiber elements are high in volumetric efficiency and located in one common pressure vessel in order to further reduce the installation volume. This design makes this unit best suited to a super-large seawater desalination plants.
Since product water of each RO element in the module can be taken to measure the conductivity and disinfectant can be easily charged, monitoring and storage preparation is easy. The membrane chemistry based on CTA allows use of chlorine disinfectant to prevent bio-fouling, the greatest operational problem in seawater desalination, especially in cases of open sea intake.
  <HL Outline Specifications>


(Diameter x Length)
[mm x mm]
Product Flow Rate*1
Salt Rejection*1,*2


380 x 4433
The product flow rate and the salt rejection indicate values obtained under the test conditions two hours after putting the module into initial operation.
The salt rejection defines the product quality and is indicated in the following formula.
(1 - salt concentration in product water / salt concentration in feed water) x 100[%]
  Test Conditions : 5.39MPa,35,000mg/L NaCl,25 deg.C and 30% Recovery
  "HOLLOSEP®" HL10255 is provided with 2 hollow fiber type elements in the pressure vessel similar to HM Series. Since product water of each RO element in the module can be taken to measure the conductivity, both operation and control are also easy.
  Higher Performance by Both Open-Ended Structure
Conventional RO element has hollow fibers with a single open-ended structure.
The new HL element has a structure of fibers with both open-ended,so-called B.O.E. structure. The B.O.E. type minimized pressure drop loss in the hollow fiber by creating a shorter flow distance along the fiber bore. This unique design leads to greater efficiency to achieve much higher production than conventional design of an element.
TOYOBO Membrane Products HOLLOSEP

HA Series

HR,HM Series
HB Series,HJ
HL Series

Applications of HOLLOSEP
HA Series
HR Series