Filter module with degassing feature

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawing, there is shown in FIG.
1 a filter module 1 comprising a conventional cartridge filter element 2 in a housing 3.
The housing 3 includes an inlet 4 for the aqueous medium to be filtered, and inlet plenum 5, and an outlet port 6 for filtrate removal.
The module is further equipped with a degassing fitting collectively comprising a valve seat 7, a pressure relief valve 8, a gas outlet port 9, a hydrophobic membrane 10 and an optional membrane support 11.
Note that such an arrangement results in the hydrophobic membrane 10 separating inlet plenum 5 from pressure relief valve 8.
The hydrophobic membrane 10 is gas-permeable but substantially impermeable to aqueous media and is further substantially impermeable to particulates and microorganisms which could contaminate the inside of the filter module.
The hydrophobic membrane 10 is preferably sealed to the inner side of the housing at its periphery, which may be accomplished by heat or pressure or the injection of a sealant or a combination of any of the three.
The hydrophobic membrane 10 may optionally be supported by a membrane support element 11; double support is also possible, but not shown.
Pressure relief valve 8 is operable to open or close gas outlet port 9, and the valve 8 may threadedly engage valve seat 7, or may be biased against the same by means of a spring.
Structurally, the hydrophobic membrane 10 may be porous, nonporous, woven or nonwoven fabric, so long as it has pores not larger than about 0.
2 .
mu.
m.
Preferably the hydrophobic membrane is polymeric; especially preferred polymers are propylene, polyvinylidenefluoride, polytetrafluoroethylene and polysulfone.
In operation, the filter module of the present invention allows gas to continually move through the hydrophobic membrane 10 when the pressure relief valve 8 is open while particles or microorganisms which could cause contamination of the inside of the filter module cannot enter into the inlet plenum 5 of the housing 3