Analytical filtration bacterial analysis water membrane filtration drinking pollution testing
Apparatus for Analytical Filtration of Water Samples - the FiltrABut
The "FiltrABut" can be used for water sample membrane filtering in bacterial analysis of water.
Useful distinctions from the analogues.
Direct filtration of water sample from the sampler-bottle; without pouring the sample from the sampler-bottle into the filter funnel.
Possibility to interrupt the sample filtration and change the filter at any moment.
Second sample contamination probability is minimal, because of the water - apparatus contact area is very small.
Working pose is sitting (More comfortable for the operator).
Principle of operation
The membrane filter 1 is set on the base 2 (with a support screen), pressed to it by bottle holder 3 by means of the captive nut 4 (which is not shown on the other plans for visibility advance) and the taper joint 5 is locked with the ball cock 6. The complete filtering head FH is turned upside-down and set on the neck of sampler-bottle 7. The resulting assembly is turned upside-down and taper joint 8 is locked with the filtrate collector 9, which is connected to a suction device and equipped with a vacuum-gauge 10 and a rarefaction regulator 11.
Some quantity of liquid flows out
from the bottle-sampler 7 into the space
The cock 6 is opened and liquid filters from the space over filter 1 through it under the action of rarefaction in the collector 9. Liquid level in the space over filter 1 comes down uncovering the rim of sampler-bottle neck and an air bubble enters the sampler-bottle 7, replacing a liquid portion in it, which again shuts down air inlet in the sample-bottle. This phenomenon repeats then.
When the required volume has been filtered, the cock 6 is closed and the assembly of sampler-bottle 7 together with filtering head FH is overturned back. At that the liquid, placed above the filter 1, flows down inversely into the sampler-bottle 7, but the particles are retained on the filter 1 owing to differential pressure remaining on the filter 1 due to closed cock 6 and to impermeability of the wet membrane filter for air.
The filtering head FH is pulled off the sampler-bottle neck, disassembled, the filter 1 is changed by a new one and the next portion of liquid is filtered.
Filter diameter, mm 35 or 47
Sterilization of the base 2, holder 3 and bottle neck by flaming
Suction by any appropriate device.
Contact area of sample with the bottle holder – 4 sm2.
Sampler-bottle is in preference the hospital volumetric glass bottle for dropper.