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The permeate water flow is controlled with the automatic control valve (the permeate control
valve). And this control valve fully closes and the suction pump stops to stop the filtration
when the liquid level of the membrane submerged tank gets to the lower limit. When the
liquid level gets to the higher limit, the automatic shutter valve on the raw water feed line
closes its line to stop raw water coming.
It is recommended to install enough capacity of the buffer tank (the equalization tank) before the
membrane submerged tank to equalize the raw water flow and enable stable operation.
(3) Devices used for Membrane Filtration
Some devices used in the membrane filtration process are explained below. However some
other devices than mentioned below might be required to install case by case for the
membrane filtration.
a. Fine
screen
The raw water should be treated with 3.0 mm or under openings of the screen
before the membrane submerged tank, otherwise the membrane is polluted and
clogged with foreign substances seriously. It is recommended to use the mesh type
screen.
b. Flow control device
A flow rate controller, an automatic control valve combined with a flow meter, should
be installed on the permeate water line to control the flow rate of permeate water. In
the case of operating a number of “TMR140 Series” modules simultaneously in one
train, it is advised to install one flow rate controller for one train of the modules.
c. Differential pressure measuring instrument
The probe of the differential pressure measuring instrument should be installed on
the permeate water line and in the membrane submerged tank at the same level, to
monitor the trans-membrane pressure. In the case of operating a number of
“TMR140 Series” modules simultaneously in one train, it is advised to install one
differential pressure measuring instrument for one train of the modules.
d. Air supply unit (such as a blower)
This unit supplies air to the air diffusers of "TMR140 Series" module. The air flow
rate supplied to the module should be within the range of "Scouring Air Flow Rate"
indicated in Table III-3 at any time.
e. Air flow meter.
An air flow meter is recommended to be installed to check the flow rate of the
scouring air supplied to the module. In the case of operating a number of “TMR140
Series” modules simultaneously in one train, it is advised to install at least one air
