JP2004025182A - Dust collector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a dust-collection filter certainly backwashable by operating the backwashing mechanism of a dust collector at the optimum timing. <P>SOLUTION: The pressure loss coefficient K of a filter is calculated from a temperature and a pressure of gas to be treated at an upstream side of the dust-collection filter 20, a temperature and a pressure of permeation gas at a downstream side and a temperature, a pressure and a flow rate of the permeation gas at a downstream side of the backwashing mechanism 30. The calculated pressure loss coefficient K and a previously set pressure loss coefficient K0 are compared and in the case of K≥K0, the backwashing mechanism is operated to carry out backwash. The pressure loss coefficient K of the filter becomes constant regardless of variation of the temperature, the pressure, the flow rate and viscosity of the gas to be treated. If the operation timing of the backwashing mechanism 30 is determined based on this pressure loss coefficient K, it becomes the optimum operation timing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dust collecting device provided with a dust collecting filter for filtering and purifying dust mixed in a gas to be treated.
[0002]
[Prior art]
As one type of dust collector, for example, as shown in Japanese Patent Application Laid-Open No. 4-271806, a filter is provided in a gas passage provided in a casing, and a backwash is provided in the gas passage downstream of the filter. A mechanism is provided, and the gas to be treated is supplied from the upstream side of the filter to pass from one side of the partition wall of the filter to the other side, and dust mixed with the gas to be treated is supplied to one side of the partition wall. And the backwashing mechanism ejects backwashing gas from the backwashing mechanism to allow the backwashing gas to permeate from the other side of the filter partition wall to one side, thereby separating dust adhering to one side of the filter partition wall. There is a dust collector.
[0003]
In the dust collector, dust mixed with the gas to be treated during operation is collected on one side of the partition wall of the filter and gradually adheres to the filter to reduce the filtration efficiency. After the pressure loss reaches a certain value, the backwashing mechanism is operated to blow backwash gas to the other side of the partition of the filter and pass from the other side of the partition to one side, and dust adhering to one side of the partition. Backwashing method for removing the filter and eliminating clogging of the filter to improve the filtration efficiency of the filter.
[0004]
[Problems to be solved by the invention]
By the way, in the dust collector of this type, when the type and supply condition of the gas to be treated, for example, the mixed amount of dust in the gas to be treated, the supply amount of the gas to be treated, the temperature, the pressure, and the like fluctuate, the above-described cleaning is performed. If the method is adopted, the operation timing of the backwash mechanism is delayed, so that the dust adhering to the filter partition cannot be sufficiently removed, or the operation timing is too early to perform unnecessary backwashing. It becomes.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to operate a backwashing mechanism at an appropriate timing, and to employ a backwashing method employing a backwashing method capable of efficiently removing dust accumulated on a partition wall of a filter. Is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a casing provided at an upper part of a hopper forming a dust accommodating chamber, and a casing provided inside the casing and supplied to a lower portion of the casing located upstream thereof. A dust collecting filter for adhering and filtering dust from the gas to be treated, and a dust filter attached to the casing downstream of the dust collecting filter and adhering the dust to the dust collecting filter during operation thereof from the dust collecting filter. In a dust collector provided with a backwash mechanism for dropping into a hopper,
First detecting means for detecting a temperature (T1) and a pressure (P1) of the gas to be treated upstream of the dust collecting filter;
A second detecting means for detecting a temperature (T2) and a pressure (P2) of the purified gas flowing out of the dust filter to an upper portion of the casing located downstream of the dust filter; Third detection means for detecting a flow rate (Q1) of the purified gas flowing out of the casing;
The average of the gas to be processed passing through the dust collection filter based on the temperature (T1, T2), pressure (P1, P2) and flow rate [Q1] detected by the first, second, and third detection means. Gas temperature [T = f (T1, T2)], gas flow rate [Q = f (Q1, T3, T, P3)], gas viscosity [η = f (T)], and filter pressure loss coefficient [K = f (ΔP , Q, η)], and when the calculated value of the filter pressure loss coefficient K is equal to or greater than a predetermined value K0, the backwashing mechanism is operated to set the value of the filter pressure loss coefficient K to a predetermined value. A dust collector provided with an electric control device for stopping the backwashing mechanism when the value becomes equal to or less than the value K0.
[0007]
In the dust collector of the present invention, the backwash of the filter is performed at a constant pressure P, and the filter pressure loss coefficient K is equal to or larger than a set value K0 even when the backwash of the filter is performed at a constant pressure P. , The backwashing can be performed by increasing the pressure (P + α).
[0008]
[Action and Effect of the Invention]
In the dust collector of the type targeted by the present invention, backwashing is optimal according to the amount of dust adhering to one side of the partition wall of the filter, but the adhering dust cannot be measured, There is no dust adhesion state other than estimated by filter pressure loss. However, even when the amount of dust adhering to the filter is the same, the filter pressure loss varies depending on the supply amount of the supplied gas to be processed, the mixed amount of dust, the temperature, the pressure, and the like.
[0009]
In order to cope with this, in the dust collector of the present invention, the temperature T1 and the pressure P1 of the gas to be treated on the upstream side of the filter, the temperature T2 and the pressure P2 of the permeated gas on the downstream side of the filter, and the backwashing mechanism Temperature T3, pressure P3, and the flow rate Q1 of the gas to be treated or the permeated gas on the downstream side of the filter are measured, and from these measured values, the average gas temperature [T = f (T1, T2)] in the filter, the gas flow rate [Q = f (Q1, T3, T, P3)], gas viscosity [η = f (T)], filter pressure loss coefficient [K = f (ΔP, Q, η)], and calculated filter pressure loss When the value of the coefficient K becomes equal to or greater than a preset value K0 of the filter pressure loss coefficient, the backwashing mechanism is operated to perform backwashing until the filter pressure loss coefficient K becomes less than the set value K0.
[0010]
If such a backwashing method is adopted, the operation timing of the backwashing mechanism is optimized, and by operating the backwashing mechanism at an appropriate timing, dust adhering to the partition wall of the filter can be efficiently removed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a dust collector according to the present invention. This dust collecting apparatus includes a dust collecting filter 20 housed in a casing 10, a backwashing mechanism 30 disposed above the casing 10, and a control mechanism 40 for controlling the operation of the backwashing mechanism 30. .
[0012]
In the above dust collector, the casing 10 has a quadrangular cylindrical main body 11, a pyramid-shaped hopper 12 fixed to the lower end of the cylindrical main body 11 and extending downward, and a cylindrical shape fixed to the lower end of the hopper 12. And the accommodation room 13. The cylindrical body 11 has a clean gas discharge hole 11a on the upper side and a gas supply hole 12a on the side of the hopper 12, and the dust collection filter 20 is provided in the cylindrical body 11. Thus, it is disposed between the supply hole 12a and the discharge hole 11a.
[0013]
The dust collecting filter 20 is the same as the filter employed in the dust collecting apparatus disclosed in Japanese Patent Laid-Open No. 4-271806, and has a plurality of ceramic filter elements 21 having a substantially L-shaped cross section and a predetermined height. The outer shells 22a and 22b are integrated from each other by being tightened from the outside. Each filter element 21 has a honeycomb shape having a number of inner holes arranged in parallel with each other. In each inner hole, an upstream end is opened and a downstream end is plugged, and a first inner hole is formed. And a second inner hole that is sealed and has an open downstream end.
[0014]
The dust collecting filter 20 receives the outer shells 22 a and 22 b at a lower flange portion 11 b provided on the inner wall of the cylindrical body 11 in a state where the upstream end is received by a receiving member 23, and an upper flange. It is fastened and fixed by a bolt 11d provided in the portion 11c.
[0015]
In the dust collecting filter 20, a plurality of lids 24, 25 are fixed to the upper ends of the outer shells 22a, 22b. Each of the lids 24 and 25 has a box-like shape whose only lower end is open. The lids 24 and 25 are positioned with a predetermined distance from the downstream end of each filter element 21 so that the downstream end of the filter element 21 is positioned at a predetermined distance. The closed chamber R is formed by covering each of the sections. In each of the lids 24, 25, an inflow / outflow pipe 24a, 25a is provided at the center of the upper wall of the lid main bodies 24, 25. The inflow / outflow pipes 24a, 25a extend vertically through the upper walls of the lid bodies 24, 25.
[0016]
The backwashing mechanism 30 includes ejection pipes 31 and 32 provided through the upper surface of the cylindrical body 11 of the casing 10, a supply line 33 of compressed air connected to the ejection pipes 31 and 32, and a supply pipe 33. The air conditioner includes a compressor 34 connected to the pipe 33, an air tank 35 interposed in the supply pipe 33, an on-off valve 36a and a flow control valve 36b. Solenoid valves are employed as the on-off valve 36a and the flow control valve 36b.
[0017]
In the backwash mechanism 30, when the compressor 34 is driven, the open / close valve 36a, or the open / close valve 36a and the flow control valve 36b are opened, so that compressed air is formed above the filter element 21 via the ejection pipes 31 and 32. The dust ejected into the closed chamber R and collected by and adhered to each filter element 21 is released. The operation of the compressor 34, the opening / closing valve 36a, and the flow regulating valve 36b is controlled by the control mechanism 40.
[0018]
The control mechanism 40 includes a controller 41 mainly composed of a microcomputer and drive circuits 42a, 42b, and 42c connected to the controller 41. The control mechanism 40 is provided upstream of the dust collection filter 20 in the casing 10. The first temperature sensor 43a and the first pressure sensor 44a provided, the second temperature sensor 43b and the second pressure sensor 44b provided downstream of the dust filter 20, and the ejection of each of the backwash mechanism 30. A third temperature sensor 43c, a third pressure sensor 44c, and a flow rate sensor 45 are provided downstream of the tubes 31, 32. Each of the temperature sensors 43a to 43c, each of the pressure sensors 44a to 44c, and the flow sensor 45 are connected to the controller 41, respectively.
[0019]
Each of the temperature sensors 43a to 43c, each of the pressure sensors 44a to 44c, and the flow rate sensor 45 are provided with a temperature T1 and a pressure P1 of the gas to be processed on the upstream side of the dust collection filter 20, a temperature T2 of a permeated gas on the downstream side of the filter 20, and a pressure, respectively. P2, the temperature T3 of the permeated gas downstream of the backwash mechanism 30, the pressure P3, and the flow rate Q1 of the permeated gas are detected, and these values are output to the controller 41 as detection signals.
[0020]
The controller 41 determines the average gas temperature [T = f (T1, T2)], the gas flow rate [Q = f (Q1, T3, T, P3)], the gas viscosity [ η = f (T)], the filter pressure loss coefficient [K = f (ΔP, Q, η)] is calculated, and the calculated value of the filter pressure loss coefficient K is compared with a preset value K0 of the filter pressure loss coefficient. Then, when the filter pressure loss coefficient K becomes equal to or more than the set value K0, the backwash mechanism 30 is operated. The program for controlling the backwash mechanism 30 is executed based on the flowchart shown in FIG.
[0021]
In the dust collector, exhaust gas from a diesel engine or the like generated in a factory or the like is treated as a gas to be treated. The gas to be treated supplied at a predetermined pressure into the casing 10 from the supply hole 12a is a dust filter. The filter element 21 reaches the upstream end of each filter element 21 at 20 and is introduced into a number of first inner holes of the filter element 21 that is open at the upstream end. The gas to be treated introduced into each first inner hole passes through each partition and flows out to each second inner hole. During this time, dust in the gas to be treated is collected and adhered to each partition, and the permeated gas is The purified gas flows into the closed chambers R from the openings at the downstream ends of the filter elements 21 in the second inner holes as the processed gas. The permeated gas that has flowed into each closed chamber R flows out of each of the inflow / outflow pipes 24a and 25a to an upper portion in the cylindrical body 11, and is discharged to the outside through the discharge holes 11a.
[0022]
In the dust collecting apparatus, the dust collecting filter 20 is back-washed by the back washing mechanism 30 during the processing of the gas to be treated, and the dust adhering to one side of the partition wall of each filter element 21 is separated, and the separated dust is removed. Is dropped into the accommodation room 13. The operation of the backwash mechanism 30 is controlled by the control mechanism 40 based on the flowchart shown in FIG.
[0023]
The control mechanism 40 is driven by the operation of the dust collector, and the controller 41 performs initial setting in step 51 of the flowchart, holds the compressor 34 in the stopped state, and holds the on-off valve 36a and the flow rate adjusting valve 36b in the closed state. I do. Next, the controller 41 determines in step 52 the average gas temperature in the filter 20 [T = f (T1, T2)] based on the detection signals from the temperature sensors 43a to 43c, the pressure sensors 44a to 44c, and the flow rate sensor 45. , A gas flow rate [Q = f (Q1, T3, T, P3)], a gas viscosity [η = f (T)], and a filter pressure loss coefficient [K = f (ΔP, Q, η)].
[0024]
In step 53, the controller 41 compares the calculated filter pressure loss coefficient K with a preset filter pressure loss coefficient K0, and if it is determined that the filter pressure loss coefficient K is lower than the set value K0, Without activating 30, the program returns to step 51 to continue the cycling program.
[0025]
When the controller 41 determines in step 53 that the filter pressure loss coefficient K is equal to or greater than the set value K0, the program proceeds to step 54, and drives the compressor 34 of the backwash mechanism 30 for a predetermined time set in step 54. At the same time, the on-off valve 36a is opened. As a result, the backwashing mechanism 30 is operated, and the compressed air having a constant pressure P is jetted through the jet pipes 31 and 32 into the respective closed chambers R formed above the filter element 21, and is captured by the filter elements 21. The dust that has collected and adhered is released.
[0026]
After a predetermined time has elapsed, the controller 41 calculates the filter pressure loss coefficient K in step 55, compares the filter pressure loss coefficient K with the set value K0 in step 56, and determines that the filter pressure loss coefficient K is lower than the set value K0. If so, the program returns to step 51 to stop the operation of the backwashing mechanism 30, and then the program proceeds to step 52.
[0027]
If the controller 41 determines in step 56 that the filter pressure loss coefficient K is equal to or greater than the set value K0, the program proceeds to step 57, and drives the compressor 34 of the backwash mechanism 30 for the predetermined time set in step 57. At the same time, the on-off valve 36a and the flow control valve 36b are opened. As a result, the compressed air (P + α) of which pressure is increased is jetted into each closed chamber R formed above the filter element 21 through each jet pipe 31, 32, and the dust collected and adhered to each filter element 21. Is released by the pressurized compressed air.
[0028]
After a predetermined time has elapsed, the controller 41 returns the program to step 55, calculates the filter pressure loss coefficient K in step 55, compares the filter pressure loss coefficient K with the set value K0 in step 56, and sets the filter pressure loss coefficient K to the set value. If it is determined that the value is lower than K0, the program returns to step 51 to stop the operation of the backwash mechanism 30, and then the program proceeds to step 52. If it is determined that the filter pressure loss coefficient K is equal to or greater than the set value K0, the program proceeds to steps 57, 55 and 56, and the program proceeds to steps 57, 55 and 56 until the filter pressure loss coefficient K becomes lower than the set value K0. Let the operation continue.
[0029]
As described above, in the above cleaning method, the temperature T1 and the pressure P1 of the gas to be treated on the upstream side of the dust collection filter 20, the temperature T2 and the pressure P2 of the permeated gas on the downstream side of the dust collection filter 20, and the backwashing mechanism 30 The temperature T3, the pressure P3, and the flow rate Q1 of the permeated gas on the downstream side are actually measured, and from the measured values, the average gas temperature [T = f (T1, T2)] and the gas flow rate [Q = F (Q1, T3, T, P3)], gas viscosity [η = f (T)], filter pressure loss coefficient [K = f (ΔP, Q, η)], and the calculated filter pressure loss coefficient K When the value becomes equal to or greater than the preset filter pressure loss coefficient set value K0, the backwashing mechanism 30 is operated to backwash the filter pressure loss coefficient K to less than the set value K0.
[0030]
Accordingly, the calculated filter pressure loss coefficient K becomes a constant value regardless of the supply pressure and supply amount of the gas to be treated, the amount of mixed dust, the temperature, the viscosity, and the like. If the backwashing mechanism 30 is operated when the coefficient becomes equal to or more than the set value K0, the operation timing of the backwashing mechanism 30 is optimized, and the backwashing mechanism 30 is operated at an accurate timing, whereby each filter element is operated. The dust adhering to the partition walls 21 can be efficiently removed.
[Brief description of the drawings]
FIG. 1 is a longitudinal perspective view showing an example of a dust collecting apparatus to which a cleaning method of the present invention is applied.
FIG. 2 is a flowchart for executing a program for controlling the operation of a backwash mechanism constituting the dust collecting apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Casing, 11 ... Cylindrical main body, 11a ... Discharge hole, 12 ... Hopper, 12a ... Supply hole, 13 ... Storage chamber, 20 ... Dust collection filter, 21 ... Filter element, 24, 25 ... Lid, 24a, 25a ... inflow / outflow pipe, 30 ... backwashing mechanism, 31, 32 ... ejection pipe, 33 ... air supply pipeline, 34 ... compressor, 35 ... air tank, 36a ... open / close valve, 36b ... flow control valve, 40 ... control mechanism, 41 ... Controllers 41, 42a-42c ... Drive circuits, 43a-43c ... Temperature sensors, 44a-44c ... Pressure sensors, 45 ... Flow rate sensors.

Claims (3)

Attach and filter dust from the gas to be treated, which is provided at the upper part of the hopper forming the dust chamber and is supplied to the lower part of the casing which is assembled inside the casing and located upstream thereof. A dust collection filter, and a backwash mechanism that is attached to the casing downstream of the dust collection filter and that causes dust adhering to the dust collection filter to drop from the dust collection filter into the hopper during operation. In the dust collector,
First detecting means for detecting a temperature (T1) and a pressure (P1) of the gas to be treated upstream of the dust collecting filter;
A second detecting means for detecting a temperature (T2) and a pressure (P2) of the purified gas flowing out of the dust filter to an upper portion of the casing located downstream of the dust filter; Third detection means for detecting a flow rate (Q1) of the purified gas flowing out of the casing;
The average of the gas to be processed passing through the dust collection filter based on the temperature (T1, T2), pressure (P1, P2) and flow rate [Q1] detected by the first, second, and third detection means. Gas temperature [T = f (T1, T2)], gas flow rate [Q = f (Q1, T3, T, P3)], gas viscosity [η = f (T)], and filter pressure loss coefficient [K = f (ΔP , Q, η)], and when the calculated value of the filter pressure loss coefficient K is equal to or greater than a predetermined value K0, the backwashing mechanism is operated to set the value of the filter pressure loss coefficient K to a predetermined value. A dust collector provided with an electric control device for stopping the backwashing mechanism when the value of K becomes equal to or less than K0. The backwashing mechanism is operated under the control of the electric control device so that the dust adhering to the dust collecting filter is dropped into the accommodation room of the hopper at a constant pressure P. Item 1. A dust collector according to Item 1. When the filter pressure loss coefficient (K) becomes greater than or equal to a predetermined value after the dust is separated from the dust filter at a constant pressure P, the dust is applied to the dust filter downstream of the dust filter. The dust collector according to claim 2, wherein the operation of the backwash mechanism is controlled by the electric control device so as to increase compressed air.

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