AUTOMATIC REPLACEMENT OF FILTER CARTRIDGE
FIG2 is a flow diagram describing the operation of the filtration unit of FIG1 (first exemplary embodiment)FIG3 is a perspective view of a filter cartridge
At working position 70, a device 80 is provided for carrying out a step 181 of detecting (FIG2) a differential pressure between the inlet and the outlet of first cartridge 11, comprising. in particular. first and second pressure sensors 282,283 arranged at the inlet and at the outlet of first cartridge 11, respectively, in order to measure a pressure drop through first cartridge 11, and comprising also a logical unit 281 configured for receiving respective fluid pressure values from pressure sensors 282,283, and for generating a related differential pressure signal 286.
flow diagram
30
filtration container
12
exchange mechanism
80
device
11
cartridge cartridges
287
signal
281
logical unit
90
control unit
183
step
181
step
182
step
10
support
184
step
286
differential pressure signal
31
aperture
75
standby position standby positions
70
position
282
pressure sensors
['1. A filtration unit (1,501) comprising: - a rear conveying section (502) for the fluid to be filtered, a cartridge-load central section (503) and a filtration and discharge front section (504) which are serially connected to each other along a longitudinal axis (9), wherein said front and rear portions (502,504) are connected to an inlet duct (7\') and an outlet duct (8\'), respectively, said inlet duct (7\') and said outlet duct (8) are aligned along said longitudinal axis (9) and arranged at opposite ends, through which said filtration unit (501) can be connected to said ducts (7,8) of the fluid to be filtered/ filtered, wherein said cartridge-load central section (503) comprises a passage channel (541) that is open at rear and front end faces (542\',542") of said cartridge-load central section (503), and that is arranged within said cartridge-load central section (503) along said longitudinal axis (9); said filtration unit (501) comprising - at least one filter cartridge (511,511\') with a cylindrical hollow filter portion (72) between a first and a second end portions (74\',74"), said first end portion (74\') protruding radially from said hollow filter portion (72) and having a through central hole (71\'), which is an opening towards outside of said filter portion (72), while said second end portion (74") is closed, wherein said first end portion (74\') has at least one seal element (84) on its own outer surface in order to provide a seal element in said passage channel (541), to prevent a gas coming from said first end portion (74\') to flow beyond said filter cartridge (511,511\'); wherein said front filter section (504) comprises a filtration container (530) aligned along said longitudinal axis (9) which is configured for receiving a first cartridge (511) with said first end portion (74\') protruding outside and with said own filtering portion (72) and said  second end portion (74") cantilevered into said filtration container (530); wherein, in a filtration step, said filter cartridge (511) is located in a working position (70) with said own filtering portion (72) within said filtration container (530); wherein said filtration unit (501) comprises a cartridge retaining means (511) in order to keep said cartridge (511) in said working position (70), said cartridge-retaining means comprises a plurality of retractable holding rods (544) configured to translate according to a transversal direction with respect to said longitudinal axis (9), between a release retracted position, in which said retaining rods (544) do not engage with said cartridge (511), and a retaining advanced position, in which said retaining rods (544) engage with cartridge (511); wherein said filtration container (530) also comprises an outlet door (550) for expelling said cartridge (511), said outlet door having an actuator, said filtration unit (501) comprising: - a releasable loading device (520) for loading filter cartridges into said filtration unit (501), a filter cartridge (511\') being in a standby position in said load container (520); wherein said cartridge-load central section (503) also comprises a loading channel (543) for displacing said cartridge (511) to be loaded into said filtration unit (501), said loading channel (543) transversally arranged with respect to said longitudinal axis (9) and open at a side surface of said cartridge-load central section (503) and within said passage channel (541); - a door (560) provided in said filtration unit (501) for separating said loading channel (543) from said passage channel (541), in order to prevent/allow a cartridge movement from said loading channel (543) to said passage channel (541), wherein said door (560) is slidably arranged between a closed position, in which a gate closing element (561) of said door (560) is arranged at the exit of said loading channel (543) within said passage channel (541) to  separate said loading channel (543) from said passage channel (541), and an open position, in which said closing element (561) clears the exit at the intersection between said loading channel (543) and said passage channel (541), which are therefore in communication with each other, wherein said door (560) has an actuator (562) and comprises a push unit (563) including at least one push member (564) for pushing said cartridge (511) through said loading channel (543) up to said working position (70), during an own slide movement from said open position to said closed position; said filtration unit (501) comprising: - a differential pressure sensor (80) arranged for measuring a pressure drop through said first filter cartridge (511) arranged in said working position (70) and configured for generating a differential pressure signal (286) responsive to said pressure drop; - a control unit (90) configured for receiving said differential pressure signal (286) and for providing an actuation signal (287) to sequentially operate a step of discharging first filter cartridge (511) from working position (70), and a step of moving said second cartridge (511\') from said standby position (75) in load container (520) to said working position (70) within said filtration container (530); - a program means resident in said control unit (90) and configured for generating said actuation signal when said differential pressure signal indicates a value of said pressure drop higher than a predetermined differential pressure threshold value; wherein in said filtration step, the filter cartridge (511) is in working position (70) with said own filtering portion (72) within said filtration container (530) and is blocked in said working position by said retaining rods (544) arranged at an advanced position, while said outlet door (550) of filtration container (530) is closed, and said gate door (560) is in said closed position below said loading channel (543) of said cartridge load central section (503); wherein in said discharging step of said first filter cartridge (511) from said working position (70), said control unit (90) is configured for bringing said retaining rods (544) from said advanced position to a retracted position, thus unlocking said filter cartridge (511) as a used cartridge, and for bringing said outlet door (550) from said closed position to said open position, said used cartridge (511) being pushed and fully introduced into said filtration chamber (530) by said the process fluid that continues to enter into said filtration unit (501), and then being expelled by gravity through said outlet door (550); wherein said step of moving a second cartridge (511\') from said standby position (75) in said load container (520) to said working position (70) within said filtration container (530), said control unit (90) is configured for moving door (560) from said closed position to said open position causing said second cartridge (511\') to fall down into said passage channel (541), wherein said control unit (90) is configured for returning said door (560) in said closed position by actuators (562), causing said push unit (563) to abut against said second cartridge (511\'), and push it up to said working position (70), where said filter portion (72) and said second end portion (74") are located in said filtration and discharge front section (504), while said first end portion (74\') stays within said cartridge load central section (503), - wherein said control unit (90) is configured for locking said second cartridge (511\') in said working position (70).']