Individual filter bag monitoring system for baghouses

Claim 2

- An apparatus for taking filter bag pressure measurements characterized by : (a) a chamber formed from a tubular sidewall (1) having an upper open end and a bottom end, said bottom end being sealed with an orifice plate (2) having an orifice (3) for the passage of a gas stream therethrough upwards towards the open end ; (b) an upstream pressure sensor tap (5) comprising a tube having an opening (8) no higher than the bottom of the orifice plate (2), said opening being located between the orifice (3) and the sidewall (1) whereby the tap opening (8) is substantially out of the flow stream ; (c) a downstream pressure sensor tap (6) comprising a tube having an opening (7) inside the chamber, said tap (6) being bent in the configuration of a loop with the open end (7) pointing downwards, said open end (7) being located at an elevated point between the orifice (3) and the sidewall (1) whereby the opening (7) is above the orifice plate (2) and substantially outside of the flow path.

Claim 3

- The apparatus of claim 1 characterized by the fact that the tubular sidewall (1) is cylindrical.

Claim 4

- The apparatus of claim 2 characterized by the fact that the sidewall (1) is higher than the height which can be achieved by a pile of dust on the orifice plate (2) against the sidewall, said height of the pile of dust being determined by the angle of repose thereof.

Claim 5

- The apparatus of claim 3 characterized by the fact that the downstream pressure tap opening (7) is above the maximum height of the dust directly below the opening (7), said maximum height being determined by the angle of repose of the dust.

Claim 6

- The apparatus of claim 1 characterized by the fact that the upstream pressure tap (5) is connected to a first valve (22) and the downstream pressure tap (6) is connected to a second valve (23) ; said first valve (22) also being connected to a first line (31) leading to a differential pressure measuring device (32) and said first valve (22) also being connected to a line (26) leading to a purge gas source (28) ; and said second valve (23) also being connected to a second line (30) leading to the differential pressure measuring device (32) and said second valve (23) also being connected to the line (26) leading to the purge gas source (28) ; and said apparatus further comprises means (37) for opening and closing the valves (22,23) to the purge gas and means (37) for opening and closing the valves (22,23) to the lines (31,30) leading to the differential pressure measuring device (32) whereby when a valve (22,23) is in one position, the line (31,30) leading to the pressure measuring device (32) is cut off and purge gas flows into the pressure tap (5,6) and when a valve (22,23) is in the other position, the purge gas is cut off and the line (31,30) leading to the pressure measuring device is open to the pressure tap (5,6).

Claim 7

- The apparatus of claim 5 characterized by the fact that the valves (22,23) are three-way solenoid valves.

Claim 8

- The apparatus of claim 6 characterized by the fact that the pressure measuring device (32) is a differential pressure transducer.

Claim 9

- An apparatus for the in situ measurement of volumetric flow through and fabric drag across an individual bag in a baghouse containing a plurality of filter bags, characterized by : (a) a plurality of pressure sensors (16;17) each of which is attached to a different bag ; each of said sensors (16;17) comprising an orifice plate (2) attached to the open end of the bag ; and a pair of pressure taps (18,19;20,21) ; one tap (18;20) being an upstream tap located on one side of the orifice plate (2) and the other tap (19;21) being a downstream tap being located on the other side of the orifice plate (2) ; (b) a plurality of upstream three-way solenoid valves (22;24), each of which is connected to a different upstream pressure tap (18;20) so that each upstream pressure tsp (18;20) from each sensor (16;17) is connected to only one valve (22;24) ; (c) a plurality of downstream solenoid valves (23;25) each of which is connected to a different downstream pressure tap (19;21) so that each downstream pressure tap (19;21) from each sensor (16;17) is connected to only one valve (23;25), thereby forming a pair of valves (22,23;24,25) for each pair of pressure taps (18,19;20,21) ; (d) a purge gas source (28) which is connected to the upstream and downstream solenoid valves (22,24;23,25) ; (e) a differential pressure transducer (32) having an upstream line (31) and a downstream line (30) wherein the upstream line (31) is connected to all of the upstream valves (22,24) and the downstream line (30) is connected to all of the downstream valves (23,25) ; (f) means (37) for activating each pair of valves (22,23;24,25) which serve a single sensor (16;17) so that for each pair, the valves (22,23;24,25) are either in one position wherein the purge gas flows into the tap (18,19;20,21) while the same tap (18,19;20,21) is cut off from the pressure transducer line (31,30), or are in the other position wherein the purge gas flow is cut off from the tap (18,19;20,21) while the tap (18,19;20,21) is connected to the pressure transducer line (31,30) ; (g) a baghouse temperature sensor (43) for measuring the gas temperature inside the baghouse ; (h) a baghouse tubesheet pressure drop sensor (44) for measuring the pressure drop across the tubesheet ; (i) a recorder (41) connected to the temperature sensor (43), the pressure drop sensor (44), and the differential pressure transducer (32), for recording the baghouse temperature, the baghouse pressure drop and the differential pressure at each sensor (16;17).

Claim 10

- An apparatus for the in situ measurement of volumetric flow through and fabric drag across an individual bag in a baghouse containing a plurality of filter bags, characterized by : (a) a plurality of pressure sensors (16;17) each of which is attached to a different bag ; each of said sensors (16;17) comprising an orifice plate (2) attached to the open end of the bag ; and a pair of pressure taps (18,19;20,21) ; one tap (18;20) being an upstream tap located on one side of the orifice plate (2) and the other tap (19;21) being a downstream tap being located on the other side of the orifice plate (2) ; (b) a plurality of upstream three-way solenoid valves (22;24), each of which is connected to a different upstream pressure tap (18;20) so that each upstream pressure tsp (18;20) from each sensor (16;17) is connected to only one valve (22;24) ; (c) a plurality of downstream solenoid valves (23;25) each of which is connected to a different downstream pressure tap (19;21) so that each downstream pressure tap (19;21) from each sensor (16;17) is connected to only one valve (23;25), thereby forming a pair of valves (22,23;24,25) for each pair of pressure taps (18,19;20,21) ; (d) a purge gas source (28) which is connected to the upstream and downstream solenoid valves (22,24;23,25) ; (e) a differential pressure transducer (32) having an upstream line (31) and a downstream line (30) wherein the upstream line (31) is connected to all of the upstream valves (22,24) and the downstream line (30) is connected to all of the downstream valves (23,25) ; (f) means (37) for activating each pair of valves (22,23;24,25) which serve a single sensor (16;17) so that for each pair, the valves (22,23;24,25) are either in one position wherein the purge gas flows into the tap (18,19;20,21) while the same tap (18,19;20,21) is cut off from the pressure transducer line (31,30), or are in the other position wherein the purge gas flow is cut off from the tap (18,19;20,21) while the tap (18,19;20,21) is connected to the pressure transducer line (31,30) ; (g) a baghouse temperature sensor (43) for measuring the gas temperature inside the baghouse ; (h) a baghouse tubesheet pressure drop sensor (44) for measuring the pressure drop across the tubesheet ; (i) a recorder (41) connected to the temperature sensor (43), the pressure drop sensor (44), and the differential pressure transducer (32), for recording the baghouse temperature, the baghouse pressure drop and the differential pressure at each sensor (16;17).

Claim 11

- The apparatus of claim 8 characterized by the fact that the means (37) for activating each pair of valves (22,23;24,25) is a sequence timer which is electrically connected to each pair of valves (22,23;24,25) so that the valve position of each pair (22,23;24,25) may be sequentially activated.

Claim 12

- The apparatus of claim 9 characterized by the fact that the baghouse temperature sensor (43) and the baghouse pressure drop sensor (44) are connected to the recorder (41) through a switch (42) which is activated by the sequence timer (37).

Claim 13

- The apparatus of claim 10 characterized by the fact that the data from the sequence timer (37) is fed to the recorder (41) and recorded therein.

Claim 14

- An apparatus of claim 8 characterized by the fact that the sequencing of the valves (22,23;24,25) and the output of the pressure transducers (32) and temperature sensors (43) are controlled and stored using digital processing hardware and software.