Method for operating horizontal continuous conductive heat transfer-type dryer

Abstract

To provide a new operation method of a horizontal continuous conductive heat transfer type dryer capable of realizing more stable and efficient operation by using apparent density of a dried product discharged from the horizontal continuous conductive heat transfer type dryer as a determination material.SOLUTION: A heat transfer member is provided in a body shell 10, a heating medium is made to flow in the heat transfer member, the heat transfer member is rotated, and a treatment object M is charged into the body shell 10. In the operation of the horizontal continuous conductive heat transfer-type dryer 1 in which the treatment object M is accumulated in the main body shell 10, is scraped up by the lifter 117 provided on the side peripheral portion of the heat transfer member, is brought into contact with the tube bundle 116 constituting the heat transfer member to promote drying, is transferred from the charging port 101 side to the overflow port 102 side, and is discharged from the overflow port 102 as the dried product D, the apparent density of the dried product D discharged from the overflow port 102 is obtained, and the controlled item of the horizontal continuous conductive heat transfer-type dryer 1 is proportionally changed according to the change in the apparent density.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a horizontal continuous conduction heat transfer dryer suitable for drying materials in the form of mud, cake, powder, etc., and in particular to an operating method for the horizontal continuous conduction heat transfer dryer that focuses on the apparent density of the dried product when controlling its operation. [Background technology]

[0002] Recently, environmental conservation efforts have become more common, and companies are now drying and concentrating general waste such as food waste and food processing residues, as well as sewage sludge, to reduce their volume and prevent decay before recycling or disposing of them.

[0003] One of the devices used for drying such sludge, etc. is a horizontal continuous conduction heat transfer dryer 1'. As shown in Fig. 11, for example, this device is provided with a multi-tubular heating pipe 11' inside a main body shell 10', and this multi-tubular heating pipe 11' is rotated while heating steam is circulated inside, and the material to be treated M is brought into contact with this pipe to evaporate moisture (see, for example, Patent Document 1). The material to be treated M supplied into the main shell 10' from the inlet 101' is lifted up by the lifter 117' and moves toward the overflow outlet 102' as the drying progresses, and is discharged to the outside from the overflow outlet 102' via the chute 12' in the form of a dried product D.

[0004] When operating such a horizontal continuous conduction heat transfer dryer 1', the material to be treated M (which has been dried) occupying approximately 50% of the volume of the main shell 10' is retained in the main shell 10' as a seed material, and the moisture content of the newly added material to be treated M is reduced, thereby enabling efficient drying processing.

[0005] While searching for a method for operating the horizontal continuous conduction heat transfer dryer 1', the applicant devised a new operating method for a horizontal continuous conduction heat transfer dryer, which has already been patented, by measuring the apparent density of the dried product D discharged from the horizontal continuous conduction heat transfer dryer 1' and using this measurement value as a judgment factor to adjust the amount of material M being processed in the main shell 10' to an amount that allows the horizontal continuous conduction heat transfer dryer 1' to operate efficiently, thereby enabling the drying process to be carried out appropriately even for material M whose properties fluctuate greatly (see Patent Document 2).

[0006] According to this invention, the retention rate in the main shell 10' is adjusted according to the apparent density of the dried product D discharged from the main shell 10'. Therefore, even if the apparent density of the dried product D changes due to a change in the physical properties of the material M to be treated, stable operation can be performed without causing clogging of the main shell 10' with the material M to be treated, or insufficient or excessive drying of the dried product D. Furthermore, the value of a current flowing through an electric motor (hereinafter, also referred to as a motor) that rotates the multi-tubular heating tube 11′ is compared with a heating tube drive current set value corresponding to the apparent density of the dried product D, and the opening and closing time of the dam plate 108′ is changed, so that an operation can be performed in which the retention rate of the material M to be treated in the main body shell 10′ is kept constant. In particular, by maintaining a retention rate with good heat transfer efficiency between the material M to be treated and the multi-tubular heating tube 11′, a dried product D with little moisture fluctuation can be obtained, and efficient operation can be performed.

[0007] The applicant has continued to vigorously research and develop the horizontal continuous conduction heat transfer dryer 1' and has refined the method of controlling the amount of the workpiece M being processed in the main shell 10' (the amount held in the main shell 10') using the apparent density of the dried product D as a determining factor, and has discovered that the apparent density of the dried product D can also be applied to other control items. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2005-331210 [Patent Document 2] Patent No. 5330920 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention was made against this background, and the technical objective was to develop a new operating method for a horizontal continuous conduction heat transfer dryer that can achieve more stable and efficient operation by using the apparent density of the dried product discharged from the horizontal continuous conduction heat transfer dryer as a criterion for making a judgment. [Means for solving the problem]

[0010] That is, the method of operating a horizontal continuous conduction heat transfer dryer according to claim 1 includes: a heat transfer member provided in a main body shell; rotating the heat transfer member while flowing a heating medium therethrough; introducing an object to be treated into the main body shell; and lifting the object to be treated up by a lifter provided on a side periphery of the heat transfer member while retaining the object in the main body shell. It is brought into contact with the tube bundle that constitutes the heat transfer member to promote drying, and In the operation of a horizontal continuous conduction heat transfer dryer, which transfers materials from the inlet side to the overflow outlet side and discharges them as dried products from the overflow outlet, The apparent density of the dried product discharged from the overflow outlet is determined, and the controlled items of the horizontal continuous conduction heat transfer dryer are proportionally varied in accordance with the fluctuations in the apparent density.

[0011] In addition to the above requirements, the operating method of the horizontal continuous conduction heat transfer dryer described in claim 2 is characterized in that the controlled item of the horizontal continuous conduction heat transfer dryer is a "judgment control" regarding the current value of the motor that rotates the heat transfer member, and the residence time of the workpiece located within the main body shell is kept appropriate by proportionally varying the "set value" in this "judgment control."

[0012] Furthermore, the operating method of a horizontal continuous conduction heat transfer dryer described in claim 3 is characterized in that, in addition to the requirements of claim 1, the controlled item of the horizontal continuous conduction heat transfer dryer is the "closing time" of the discharge damper that opens and closes the overflow outlet, and by controlling this value, the residence time of the treated material located within the main body shell is kept appropriate.

[0013] Furthermore, the operating method of a horizontal continuous conduction heat transfer dryer described in claim 4 is characterized in that, in addition to the requirements described in claim 1, the controlled item of the horizontal continuous conduction heat transfer dryer is the "frequency" of the material feeding device for feeding the material into the main body shell, and by controlling this value, the residence time of the material located in the main body shell is kept appropriate.

[0014] A method of operating a horizontal continuous conduction heat transfer dryer according to claim 5 includes: providing a heat transfer member in a main body shell; rotating the heat transfer member while flowing a heating medium therethrough; introducing an object to be treated into the main body shell; and lifting the object to be treated up by a lifter provided on a side periphery of the heat transfer member while retaining the object in the main body shell. It is brought into contact with the tube bundle that constitutes the heat transfer member to promote drying, and In the operation of a horizontal continuous conduction heat transfer dryer, which transfers materials from the inlet side to the overflow outlet side and discharges them as dried products from the overflow outlet, The apparent density of the dried product discharged from the overflow port is calculated, and the controlled items of the horizontal continuous conduction heat transfer dryer are proportionally changed according to the change in the apparent density. The apparent density of the dry product is characterized in that it is determined by measuring the weight of a measuring cup filled with the dry product multiple times and using the average value.

[0015] The method of operating a horizontal continuous conduction heat transfer dryer according to claim 6 is characterized in that, in addition to the requirements of claim 5, a lower limit and an upper limit are set for the apparent density, and proportional fluctuations of the set values ​​in the control items are reflected within the range between the lower limit and the upper limit.

[0016] The method of operating a horizontal continuous conduction heat transfer dryer described in claim 7 is characterized in that, in addition to the requirements of claim 5, the fine powder discharged from the exhaust port is supplied to a measuring cup in addition to the dried product discharged from the overflow port. The above problems are solved by the configurations of the inventions described in each claim. [Effects of the Invention]

[0017] First, according to the invention described in claim 1, the controlled items of the horizontal continuous conduction heat transfer dryer are changed proportionally in response to fluctuations in apparent density, so that the controlled items can be changed gradually in response to fluctuations in apparent density. As a result, the judgment and burden on the operator are reduced, and stable operation can be achieved without causing clogging of the main body shell due to the materials to be treated, or insufficient or excessive drying of the dried products.

[0018] Furthermore, according to the invention described in claim 2, the setting value in the judgment control regarding the current value of the motor that rotates the heat transfer member is changed proportionally in accordance with the fluctuation in apparent density, thereby maintaining an appropriate residence time for the material to be treated located within the main shell; more specifically, the holding amount is adjusted to an appropriate amount in accordance with the fluctuation in apparent density; in other words, the time for receiving heat from the heat transfer member is adjusted appropriately in accordance with the apparent density, thereby suppressing fluctuations in the moisture content of the dried product.

[0019] Furthermore, according to the invention described in claim 3, the "closing time" of the discharge damper that opens and closes the overflow outlet is varied proportionally in accordance with fluctuations in apparent density, thereby maintaining an appropriate residence time for the material to be treated located within the main shell; more specifically, the holding amount is adjusted to an appropriate amount in accordance with fluctuations in apparent density; in other words, the time for receiving heat from the heat transfer member is adjusted appropriately in accordance with the apparent density, thereby suppressing fluctuations in the moisture content of the dried product.

[0020] Furthermore, according to the invention described in claim 4, by proportionally varying the "frequency" of the material input hopper in accordance with fluctuations in apparent density, the residence time of the material located within the main shell is maintained at an appropriate level; more specifically, the holding amount is adjusted to an appropriate level in accordance with fluctuations in apparent density. In other words, the time for receiving heat from the heat transfer member is adjusted appropriately in accordance with the apparent density, thereby suppressing fluctuations in the moisture content of the dried product.

[0021] Furthermore, according to the invention as set forth in claim 5, it is possible to avoid control proceeding according to an extremely large (or small) "apparent density" value that occurs irregularly.

[0022] Furthermore, according to the invention described in claim 6, it is possible to avoid a drop in drying efficiency when the apparent density is smaller than the lower limit, while it is possible to avoid excessive drying efficiency when the apparent density is larger than the upper limit.

[0023] Furthermore, according to the invention described in claim 7, the apparent density value can be determined to be close to the value of the dried product actually located inside the main body shell, allowing for even more appropriate control. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing a control system for implementing a method for operating a horizontal continuous conduction heat transfer dryer. [Figure 2] FIG. 1 is a partially cutaway front view of a horizontal continuous conduction heat transfer dryer. [Figure 3] 1A is a partially perspective left side view of a horizontal continuous conduction heat transfer dryer, and FIG. 1B is a partially cutaway right side view thereof. [Figure 4] FIG. 10 is a skeletal diagram showing how the object to be treated is discharged from the main body shell. [Figure 5] FIG. 1 is a skeletal diagram showing a discharge conveyor and an apparent density measuring device. [Figure 6] 1 is a flowchart showing a method for operating the horizontal continuous conduction heat transfer dryer of the present invention. [Figure 7] 1 is a graph showing the relationship between apparent density and controlled elements. [Figure 8] 10 is a flowchart showing an example of input amount control. [Figure 9] 10 is a flowchart illustrating an example of a discharge amount control. [Figure 10] 1 is a block diagram showing an apparent density measuring device and an embodiment in which the device is installed in a different manner. [Figure 11] 1A and 1B are a front view and a side view, partly cut away, of an existing horizontal continuous conduction heat transfer dryer. DETAILED DESCRIPTION OF THE INVENTION

[0025] The best mode of operation of the horizontal continuous conduction heat transfer dryer of the present invention is as shown in the following example, but appropriate modifications can be made to this example within the scope of the technical concept of the present invention. [Example]

[0026] Hereinafter, the operation method of the horizontal continuous conduction heat transfer dryer of the present invention will be described in detail together with its operating mode after explaining the configuration of the horizontal continuous conduction heat transfer dryer 1. First, the horizontal continuous conduction heat transfer dryer 1 is an apparatus suitable for drying a material M to be treated that is in a muddy, cake-like, powdery or granular state, and is an apparatus for obtaining a dried product D by retaining the material M to be treated while evaporating volatile components such as moisture. As shown in Figs. 1 to 3 , this dryer is provided with a multi-tubular heating pipe 11 inside a main body shell 10 provided on a machine frame 100, and this multi-tubular heating pipe 11 is rotated while steam as a heating medium flows inside the multi-tubular heating pipe 11, and the material M to be treated is retained inside the main body shell 10 and brought into contact with the multi-tubular heating pipe 11 to dry.

[0027] As shown in FIG. 3, the main body shell 10 is, for example, a hollow member having an oblong cross section, and is formed with an inlet 101, an overflow port 102, a carrier gas port 103, and an exhaust port 104. The inlets 101 are formed at multiple locations on the upper portion of the main body shell 10. First, a first inlet 101a is formed near the exhaust port 104 located at the upper left side in FIG. 2 . A second inlet 101b is formed closer to the center than the exhaust port 104. A third inlet 101c is formed between the second inlet 101b and the carrier gas port 103 located at the upper right side in FIG. 2 . While the inlets 101 are formed at three locations in this embodiment, they may be formed at one, two, or four or more locations depending on the specifications of the horizontal continuous conduction heat transfer dryer 1. The location of the inlets 101 is not particularly limited; they may be formed at any location where the material M can be introduced into the main body shell 10. Then, the material to be treated M is pumped by a material to be treated input device 6 equipped with, for example, a sludge pump, and distributed to each input port 101. The material to be treated input device 6 is driven by a motor 61, and the amount of material to be treated M to be pumped (the amount of sludge, more specifically, the material to be treated input speed described later) can be changed by changing the set value of the frequency of an inverter connected to the motor 61. It should be noted that since it is difficult to transport powdery or granular material M by a material input device 6 such as a sludge pump, a screw conveyor or the like may be used.

[0028] The main body shell 10 and the multi-tubular heating tube 11 are installed in the machine frame 100 in a horizontal state, or are installed in the machine frame 100 at an incline so that the exhaust port 104 side is slightly higher than the carrier gas port 103 side. Furthermore, the main body shell 10 has a double jacket structure, and a steam passage is formed from a steam supply port 105 formed near the inlet 101a to a drain port 106 formed below the overflow port 102, thereby enabling the temperature inside the main body shell 10 to be raised. Note that instead of such a double jacket structure, a tracing pipe or the like can also be installed.

[0029] The overflow outlet 102 is formed on a high side surface of the main body shell 10, and is provided with a fixed dam plate 107 and a dam plate 108 for covering a portion of the overflow outlet 102. The fixed dam plate 107 is appropriately fixed with bolts (not shown) or the like so that a gap is formed between the upper and lower ends of the overflow outlet 102. Meanwhile, the dam plate 108 is provided on the back side of the fixed dam plate 107 and is driven by an air cylinder 109 and slides up and down via an appropriate link mechanism (not shown). In this embodiment, when the dam plate 108 slides upward, the lower portion of the fixed dam plate 107 is opened as shown in FIG. 4(b), and the dried product D overflows from this open portion and is discharged from the main body shell 10. When the dam plate 108 is lowered by the air cylinder 109, the open portion is closed, and the discharge of the dried product D from the main body shell 10 is stopped as shown in FIG. 4(a). The overflow outlet 102b shown in Figure 4(a) is formed on the top of the fixed dam plate 107, and is intended to allow discharge over the fixed dam plate 107 if the retention rate within the main shell 10 increases for some reason. As shown in FIG. 1, the air cylinder 109 is driven by supplying or cutting off the compressed air by opening or closing an electromagnetic valve 109a. The solenoid valve 109a is repeatedly and continuously opened and closed during the drying operation in accordance with the set value of the opening and closing time of the barrier plate 108, which will be described later. Furthermore, a chute 12 is provided on the outside of the overflow port 102, the fixed dam plate 107 and the dam plate 108 so as to cover them, and a rotary valve 122 is provided at a dried product discharge port 121 formed in this chute 12.

[0030] The multi-tubular heating tube 11 is provided with end plates 112 on both sides of a tube bundle 116 formed by arranging a plurality of tubes in a cylindrical shape, and with a shaft 113 at the center of the end plates 112, and the shaft 113 is rotatably supported by a bearing block 114 provided on the machine frame 100. A motor 14 is provided on the machine frame 100 as a drive device for rotating the multi-tubular heating tube 11. Rotary joints 115 (115a, 115b) are attached to both ends of the shaft 113 and connected to a tube bundle 116. A seal mechanism 13 is provided between the shaft 113 and the main body shell 10 to block the outside air. The tube bundle 116 is provided on its periphery with a number of angles 111 (12 in this embodiment) to which are attached a plurality of lifters 117 and feed blades 118 at appropriate angles, and these lift the material M to be treated, causing it to come into contact with each tube of the tube bundle 116 and move from the inlet 101 side to the overflow outlet 102 side.

[0031] Although not shown, a steam generator is installed in addition to the horizontal continuous conduction heat transfer dryer 1, and an appropriate device such as a U-shaped, straight pipe, or helical coil type is used. A pipe is connected from this steam generator to the rotary joint 115a and the steam supply port 105 in the horizontal continuous conduction heat transfer dryer 1. Furthermore, a carrier gas is supplied into the main body shell 10 from a carrier gas port 103. Volatile components volatilized from the workpiece M by heating in the multi-tubular heating tube 11 are carried out of the main body shell 10 by the carrier gas through an exhaust port 104. Since the carrier gas contains not only the volatile components but also fine powder generated from the workpiece M, a bag filter 7, which is an example of a dust removal device, is provided downstream of the exhaust port 104. Furthermore, a temperature sensor 16 is provided on the path through which the carrier gas flows after the exhaust port 104 . Furthermore, a temperature sensor 15 is provided on the discharge side within the main body shell 10, that is, near the overflow port 102.

[0032] As an example, an apparent density measuring device 2 is provided downstream of the dried product discharge port 121 of the chute 12. As shown in FIG. 5 as an example, this device calculates the apparent density of the dried product D from the weight of the dried product D taken into a measuring cup 21 provided in a housing 20 and the volume of the measuring cup 21. An example of the detailed configuration of such an apparent density measuring device 2 will be shown below. An inlet 20a is formed in the upper part of the housing 20, while an outlet 20b is formed in the lower part. An inclined plate 22 is provided directly below the inlet 20a, and a measuring cup 21 is provided further below that. The inclined direction of the inclined plate 22 can be freely changed by the expansion and contraction action of the switching damper 23, and it is possible to select and form either a path from the inlet 20a to the measuring cup 21, or a path from the inlet 20a directly to the outlet 20b.

[0033] A cylinder 24 equipped with a scraping plate 25 is provided above the measuring cup 21, and the scraping plate 25 moves along the upper edge of the measuring cup 21 as the cylinder 24 expands and contracts. The measuring cup 21 is also capable of being weighed by a measuring device 26 . Although not shown, the measuring cup 21 is capable of automatically discharging its contents to the discharge port 20b by means of an inverting mechanism, an air blower, or the like.

[0034] Next, the connection between the apparent density measuring device 2 and the horizontal continuous conduction heat transfer dryer 1 will be described. 1, a discharge conveyor 41 is provided between the apparent density measuring device 2 and the horizontal continuous conduction heat transfer dryer 1, and an inlet 411 of this discharge conveyor 41 is connected to the dried product outlet 121 of the horizontal continuous conduction heat transfer dryer 1. Similarly, an inlet 412 provided downstream of the inlet 411 is connected to the outlet 71 of the bag filter 7 connected to the exhaust outlet 104. A dried sludge hopper 5 is disposed below a discharge port 413 provided downstream of the inlet 412 with a damper 415 interposed therebetween. Furthermore, below the discharge outlet 414, which is located downstream of the discharge outlet 413, the inlet 20a of the apparent density measuring device 2 is arranged, and below the discharge outlet 20b, the dried sludge hopper 5 is arranged.

[0035] By adopting such a configuration of the horizontal continuous conduction heat transfer dryer 1 and the apparent density measuring device 2, it is possible to extract and measure a portion of the dried product D discharged from the dried product discharge outlet 121. Furthermore, it is possible to measure the dried product D discharged from the dried product discharge outlet 121 in a state where fine dried product D discharged from the exhaust port 104 is mixed in. Therefore, the measurement result by the apparent density measuring device 2 can be made close to the apparent density of the dried product D in the main body shell 10. As a means for further improving the measurement accuracy, a configuration can be adopted in which a buffer hopper or the like is provided between the dried product discharge outlet 121 and the inlet 411 and between the discharge outlet 71 and the inlet 412, thereby absorbing the time lag of the dried product D discharged from these two discharge outlets. Alternatively, a paddle screw conveyor may be used as the discharge conveyor 41, so that the dried product D from the dried product discharge outlet 121 and the dried product D from the discharge outlet 71 are more mixed and made uniform, and then measurement can be performed by the apparent density measuring device 2.

[0036] The horizontal continuous conduction heat transfer dryer 1 and peripheral equipment for carrying out the present invention are configured as described above as an example. The operating mode of this device and the "method for operating a horizontal continuous conduction heat transfer dryer" of the present invention will be described below with reference to the flowchart shown in FIG. 6.

[0037] (1) Preparing the dryer First, prior to operation of the horizontal continuous conduction heat transfer dryer 1, the apparent density of the dried product D and the heating tube drive current value at this apparent density, i.e., the lower limit A and upper limit B of the correction coefficients for the current value of the motor 14, are set (step S1), the lower limit C and upper limit D of the correction coefficients for the closing timer time of the overflow port 102 are set (step S2), and the lower limit E and upper limit F of the correction coefficients for the frequency of the inverter that drives the motor 61 of the material feeding device 6 are set (step S3), are input into a programmable logic controller (hereinafter referred to as PLC) not shown in the figure in the control panel 3. These set values ​​are input at the time of design or based on the operator's judgment during trial operation or operation. In addition to these settings, there are other settings to be input into the PLC, which will be described in detail later.

[0038] Furthermore, the "volume value" of the measuring cup 21 is input to the PLC. In addition, the weight W0 of the measuring cup 21 without the dried product D therein is measured by the weighing device 26 and input to the PLC.

[0039] Prior to the introduction of the workpiece M, the temperatures of the multi-tubular heating tube 11 and the main body shell 10 in the horizontal continuous conduction heat transfer dryer 1 are raised, and with the motor 14 started to rotate the multi-tubular heating tube 11, heating steam (for example, 0.5 MPa (approximately 160°C)) is supplied to the rotary joint 115a and the steam supply port 105. The heating steam supplied to the rotary joint 115a increases the temperature of the multi-tubular heating tube 11 while passing through the tube bundle 116, and eventually becomes drain, which is discharged to the outside from the rotary joint 115b on the other end side. The heating steam supplied to the steam supply port 105 increases the temperature of the main body shell 10, and eventually becomes drain, which is discharged to the outside from the drain port 106. A siphon pipe (not shown) is provided inside end plate 112 on the rotary joint 115b side, and a steam trap (not shown) is provided in the path through which the drain discharged from rotary joint 115b flows. Also, a steam trap (not shown) is provided in the path through which the drain discharged from drain port 106 flows.

[0040] (2) Drying of the treated material Next, the material to be treated M is charged into the charging port 101, and the material to be treated M charged into the charging port 101 moves from the charging port 101 side to the overflow port 102 side by the action of the feed blades 118, and is further scooped up by the lifter 117 to come into contact with the tube bundle 116 and the like, at which time it receives heat and is dried. At this time, the charging ports 101 are formed at a plurality of positions along the longitudinal direction of the multi-tubular heating tube 11, so that the heat conduction surface of the multi-tubular heating tube 11 can be used effectively and the drying efficiency can be improved.

[0041] Then, as shown in Figure 4(b), when the dam plate 108 is raised and the lower part of the fixed dam plate 107 is released, the dried product D flows out from the overflow outlet 102 and is sent to the apparent density measuring device 2 side via the chute 12. The discharge speed of the dried product D is adjusted by varying the opening and closing time of the overflow outlet 102 by raising and lowering the dam plate 108, and examples include a pattern of repeatedly opening for 2 seconds and closing for 28 seconds, or a pattern of repeatedly opening for 2 seconds and closing for 18 seconds. That is, if the overflow port 102 is closed for a short time, the dry product discharge rate will be high (the discharge amount will increase), whereas if the overflow port 102 is closed for a long time, the dry product discharge rate will be low (the discharge amount will decrease).

[0042] (3) Correction of various operating conditions based on the apparent density of the dried product As described above, once a series of operations, such as feeding the workpiece M into the horizontal continuous conduction heat transfer dryer 1 and discharging the dried product D from the horizontal continuous conduction heat transfer dryer 1, has been established, the various operating conditions are corrected according to the present invention.

[0043] (3-1) Setting the lower and upper limits of various correction coefficients (steps S1 to S4) In the present invention, the apparent density V of the dried product D discharged from the overflow port 102 is determined (measured), and the correction coefficients of the controlled items of the horizontal continuous conduction heat transfer dryer 1 are proportionally varied according to the variation of the apparent density V as shown in FIG. 7. In this case, the apparent density V of the dried product D is set to a lower limit X [kg / m 3 ] and upper limit Y [kg / m 3 ] is used within a set range (step S4). Accordingly, a lower limit value A and an upper limit value B of the correction coefficient for the current value of the motor 14 are set (step S1). Also, a lower limit C and an upper limit D of the correction coefficient for the time of the close timer are set (step S2). Also, a lower limit E and an upper limit F of the correction coefficient for the frequency of the inverter of the motor 61 are set (step S3).

[0044] The graphs shown in Figures 7(a), (b), and (c) show that the apparent density is set from a lower limit value X to an upper limit value Y, and that within this range, the correction value increases as the apparent density increases, showing a linear proportional relationship. Therefore, in Figure 7(a), correction value B is larger than correction value A. Normally, the correction value corresponding to the apparent density assumed during design is set to 1.0, correction value B is set to a value larger than 1.0, and correction value A is set to a value smaller than 1.0. The range within which the proportional relationship in this graph is determined by equation (3), which will be described later and is set in the PLC; the measured value of the apparent density is substituted into equation (3) to calculate the corresponding correction value, and this correction value is used to perform the judgment control in the flowchart, which will be described later.

[0045] Similarly, in Figure 7(b), correction value D is larger than correction value C. Normally, the correction value corresponding to the apparent density assumed during design is set to 1.0, correction value D is set to a value larger than 1.0, and correction value C is set to a value smaller than 1.0. The range within which the proportional relationship in this graph is determined by equation (4) (to be described later) set in the PLC; the measured value of the apparent density is substituted into equation (4) to calculate the corresponding correction value, and this correction value is used to control the operation of the flowchart (to be described later).

[0046] Similarly, in Figure 7(c), correction value F is larger than correction value E. Normally, the correction value corresponding to the apparent density assumed during design is set to 1.0, correction value F is set to a value larger than 1.0, and correction value E is set to a value smaller than 1.0. The range within which the proportional relationship in this graph is determined by equation (5) set in the PLC, which will be described later. The measured value of the apparent density is substituted into equation (5) to calculate the corresponding correction value, and this correction value is used to control the operation of the flowchart, which will be described later.

[0047] During test run or operation, the operator may, at his discretion, change the PLC settings to more appropriate values ​​than A, B, C, D, E, or F assumed at the time of design. Similarly, the settings of the PLC for the apparent densities X and Y can be changed to more appropriate values. Furthermore, when the apparent density is smaller than the lower limit X or larger than the upper limit Y, the correction values ​​are set to constant values ​​A, B, C, D, E, and F, as shown in the graphs of FIGS. 7(a), (b), and (c). In particular, if the apparent density remains below the lower limit X or above the upper limit Y for a certain period of time, it is necessary to change the setting of A, B, C, D, E, F, X, or Y. It should be noted that the proportional relationship may be a broken line, rather than the linear one described above, with the correction value of 1.0 corresponding to the newly set apparent density as the boundary.

[0048] (3-2) Calculation of apparent density measurement value V (step S5) Then, the damper 415 is closed to stop the discharge of the dried product D from the discharge outlet 413 of the discharge conveyor 41, and the switching damper 23 is operated so that the inclined plate 22 forms a path from the inlet 20a to the measuring cup 21. In this state, the dried product D discharged from the discharge port 414 of the discharge conveyor 41 is supplied to the measuring cup 21.

[0049] Next, when the measuring cup 21 is filled sufficiently with the dried product D and begins to overflow, the switching damper 23 is operated so that the inclined plate 22 forms a path from the inlet 20a to the outlet 20b, and the supply to the measuring cup 21 is stopped.

[0050] Next, the cylinder 24 is operated to apply the scraping plate 25 to the upper edge of the measuring cup 21, scraping off the dried product D accumulated above the upper edge, so that the measuring cup 21 is filled with the dried product D to its full capacity. In this state, the weight of the measuring cup 21 including the contents, which is the first measurement result, is measured by the weighing device 26 and input to the PLC. Since this weight is the total weight of the weight of the contents and the weight of measuring cup 21, the weight of measuring cup 21 is subtracted from the total weight, and the weight of the contents W1 is used in the calculation formula described below. The same is true for W2, W3, ... Wn described below, but for convenience, it will be described as if the weights of the contents W1, W2, W3, ... Wn are measured and input to the PLC. Next, the measuring cup 21 is rotated 180° by an inversion mechanism provided in the measuring device 26, the dried product D in the measuring cup 21 is discharged, and after the discharge, air is blown into the measuring cup 21 by a mechanism not shown. After the air blowing, the measuring cup 21 is rotated 180° again.

[0051] Then, the weight of the measuring cup 21 is measured when it is empty and compared with the empty weight preset in the PLC. If the increase in weight from the empty weight is within the allowable range preset in the PLC, the measuring cup 21 is ready to receive the dried product D dropping from the discharge outlet 414, and the switching damper 23 is operated again to position the inclined plate 22 so that the dried product D flows from the inlet 20a into the measuring cup 21. After the dried product D has accumulated above the upper edge of the measuring cup 21 in the same manner as described above, it is leveled off, and the second weight W2 is measured and entered into the PLC.

[0052] By repeating this operation, weight measurements (W1, W2, W3, . . . Wn) are performed multiple times (n times) in succession. After the n measurements, the damper 415 opens and the dried product D is discharged from the discharge port 413 into the dried sludge hopper 5. After a certain time has elapsed, the weight is measured again n times as described above. Furthermore, for each such weight measurement, the apparent density measurements V1, V2, ..., Vn are calculated using the following equation (1). V1 = W1 / measuring cup capacity, V2 = W2 / measuring cup capacity, Vn = Wn / measuring cup capacity, Equation (1) The average value V of the apparent density measurements is then calculated using the following equation (2). V=(V1+V2+ + Vn) / n [kg / m3] Formula (2)

[0053] (3-3) Determination of various correction coefficients Next, using the apparent density measurement V described above, various correction factors are determined as follows: (a) When the apparent density measurement value V>the apparent density setting upper limit value Y (steps S6 and S7) First, when the apparent density measurement value V>the apparent density upper limit value Y, the correction coefficient when the apparent density is Y is adopted. Current value correction coefficient = B Closed timer correction factor = D Frequency correction factor = F

[0054] (b) When the apparent density measurement value V is less than the apparent density setting lower limit value X (steps S8 and S9) Furthermore, when the apparent density measurement value V<the apparent density setting lower limit value X, the correction coefficient when the apparent density is X is used. Current correction coefficient = A Closed timer correction factor = C Frequency correction factor = E

[0055] (c) When the apparent density setting lower limit value X≦apparent density measurement value V≦apparent density setting upper limit value Y (Steps S8, S10) When the apparent density lower limit X≦the apparent density measurement value V≦the apparent density upper limit Y, the correction coefficients are calculated by the following equations (3), (4), and (5). Current value correction coefficient = ((BA) / (YX))*(VX)+A Equation (3) Closed timer correction coefficient = ((DC) / (YX))*(VX)+C Equation (4) Frequency correction coefficient = ((FE) / (YX))*(VX)+E Equation (5)

[0056] (4) Control using the obtained correction coefficient Here, an example of how the current value correction coefficient, the close timer correction coefficient, and the frequency correction coefficient obtained as described above are handled in actual control will be described with reference to the flowcharts shown in FIGS.

[0057] (4-1) Input amount control First, regarding the input amount control, in the input amount control flowchart shown in FIG. 8, the frequency correction coefficient of the workpiece input device 6 is used, and if the judgment in step S11 is NO and the judgment in step S21 is NO, the process proceeds to step S31. The determination in step S11 is to determine whether or not the current value I flowing through the motor 14 is equal to or greater than the "corrected H current value."

[0058] Here, the "corrected H current value" of the current value will be explained. First, the current value that allows stable and efficient steady-state drying operation is set in the PLC at the time of designing the motor 14 or at the judgment of the operator during trial operation or operation, and this is the M current value. In relation to this M current value, a current value higher than the M current value by, for example, 5 [A] is called the H current value and is set in advance to the PLC. The corrected H current value is obtained by multiplying this H current value by a current value correction coefficient calculated by equation (3) that reflects the influence of the measured apparent density of the dried product D, and is set to the PLC. Corrected H current value = H current value x current value correction coefficient

[0059] Similarly, a current value 10 [A] higher is set as the HH current value, a current value 5 [A] lower is set as the L current value, and a current value 10 [A] lower is set as the LL current value in the PLC. In other words, in the present invention, the corrected HH current value, corrected H current value, corrected M current value, corrected L current value, and corrected LL current value obtained by multiplying these HH current value, H current value, M current value, L current value, and LL current value by a current value correction coefficient calculated by equation (3) that reflects the influence of the apparent density measurement value of the dried product D are set in the PLC and used for judgment control among the control items. Corrected HH current value = HH current value x current value correction coefficient Corrected M current value = M current value x current value correction coefficient Corrected L current value = L current value x current value correction coefficient Corrected LL current value = LL current value x current value correction coefficient Note that "predetermined" means a value set in the PLC at the time of design, or at the discretion of an operator during test run or operation, and "pre-set" has the same meaning.

[0060] The determination in step S21 is to determine whether or not the exhaust gas temperature T16 detected by the temperature sensor 16 is equal to or lower than a predetermined exhaust gas temperature "L".

[0061] Then, in step S31, it is determined whether or not the dryer discharge side temperature T15 (the value detected by the temperature sensor 15) is equal to or higher than a predetermined temperature H. If the answer is YES, the process proceeds to step S32, where the drive frequency of the motor 61 is changed to the "corrected H frequency" described below. Corrected H frequency = H frequency x frequency correction coefficient Here, the H frequency is the set frequency of the inverter in the treatment object input device that is set in advance in the PLC. Note that the M frequency, L frequency, and LL frequency are listed below, but like the H frequency, these are frequencies that are set in advance in the PLC. The order of the frequencies is H frequency > M frequency > L frequency > LL frequency. When the frequency is low, the amount of the material M supplied into the main body shell 10 decreases, so the material M in the main body shell 10 acts in the direction of decreasing.

[0062] On the other hand, if the result of step S31 is NO, the process proceeds to step S41, where it is determined whether or not the dryer discharge side temperature T15 (the value detected by temperature sensor 15) is equal to or higher than a predetermined temperature M. If the answer is YES, the process proceeds to step S42, where the drive frequency of the motor 61 is changed to the "corrected M frequency" described below. Corrected M frequency = M frequency x frequency correction coefficient

[0063] On the other hand, if the result of step S41 is NO, the process proceeds to step S51, where it is determined whether or not the dryer discharge side temperature T15 (the value detected by temperature sensor 15) is equal to or higher than a predetermined temperature L. If the answer is YES, the process proceeds to step S52, where the drive frequency of the motor 61 is changed to the "corrected L frequency" described below. Corrected L frequency = L frequency × frequency correction coefficient

[0064] On the other hand, if the result of step S51 is NO, the process proceeds to step S61, where it is determined whether or not the dryer discharge side temperature T15 (the value detected by temperature sensor 15) is equal to or higher than a predetermined temperature LL. If the answer is YES, the process proceeds to step S62, where the drive frequency of the motor 61 is changed to the "corrected LL frequency" described below. Corrected LL frequency = LL frequency x frequency correction coefficient

[0065] Conventionally, in steps S11, S32, S42, S52, and S62, operation is performed at the current value and frequency that are preset in the PLC. On the other hand, in the present invention, the apparent density of the dried product D is determined as described above, and the corrected H current value calculated using equation (3) and the corrected H frequency, corrected M frequency, corrected L frequency, and corrected LL frequency calculated using equation (5) are set in the PLC, and by operating a combination of judgment control and operation control as shown in Figure 8, more specifically, by operating to adjust the amount of workpiece M fed into the main body shell 10, it becomes possible to operate while maintaining the hold amount (also called retention amount) at an appropriate state according to the apparent density of the dried product D.

[0066] In addition, if the answer is YES in step S11, if the answer is YES in step S21, or if the answer is NO in step S61, the treatment material input device will be stopped (steps S12, S22, S71), and then the specified input stop operation (change in the operating state of each device) will be performed (steps S13, S23, S72).

[0067] (4-2) Emissions Control Next, the discharge control will be described. In the flow chart of the discharge control shown in FIG. 9, if the determination in step S101 is NO, and if the determination in step S102 is NO, the process proceeds to step S201. The determination in step S101 is to determine whether or not the current value I flowing through the motor 14 is equal to or greater than a predetermined current value "corrected HH current value." The determination in step S102 is to determine whether or not the dryer discharge side temperature T15 detected by the temperature sensor 15 is equal to or lower than a predetermined temperature "L".

[0068] Then, in step S201, it is determined whether the current value I flowing through the motor 14 is equal to or greater than the "corrected H current value." If the answer is YES, the process proceeds to step S202, where the opening and closing time of the dam board 108 is determined by setting the open timer to, for example, 3 seconds, in advance in the PLC, and multiplying the close timer (H close timer) by a close timer correction coefficient to obtain the "corrected H close timer," which is set in the PLC and used for control. Correction H close timer = H close timer x close timer correction coefficient The H-close timer is the time set in advance in the PLC. The opening and closing operation of the dam board 108 is performed based on a combination of the open timer time and the "corrected H close timer time" in the corrected H discharge control (step S202).

[0069] On the other hand, if the result of step S201 is NO, the process proceeds to step S301, where it is determined whether the current value I flowing through the motor 14 is equal to or greater than the "corrected M current value." If the result is YES, proceed to step S302, and the opening and closing time of the dam board 108 is determined by setting the open timer to, for example, 3 seconds, which is preset in the PLC, and multiplying the close timer (M close timer) by the close timer correction coefficient to obtain the "corrected M close timer," which is set in the PLC and used for control. Correction M close timer = M close timer x close timer correction coefficient The M close timer is the time of the timer that is set in advance in the PLC. The opening and closing operation of the dam plate 108 is performed based on a combination of the open timer time and the "corrected M close timer time" in the corrected M discharge control (step S302).

[0070] On the other hand, if the result of step S301 is NO, the process proceeds to step S401, where it is determined whether the current value I flowing through the motor 14 is equal to or greater than the "corrected L current value." If the result is YES, proceed to step S402, and the opening and closing time of the dam board 108 is set in the PLC as the open timer, which is preset to, for example, 3 seconds, and the time of the "corrected L closed timer" calculated by multiplying the close timer (L closed timer) by the close timer correction coefficient is set in the PLC and used for control. Corrected L-closed timer = L-closed timer x closed timer correction coefficient The L-close timer is the time set in advance in the PLC. The opening and closing operation of the dam board 108 is performed based on a combination of the open timer time and the "corrected L close timer time" in the corrected L discharge control (step S402).

[0071] On the other hand, if the result of step S401 is NO, the process proceeds to step S501, where it is determined whether the current value I flowing through the motor 14 is equal to or greater than the "corrected LL current value." If the answer is YES, the process proceeds to step S502, where the opening and closing time of the dam board 108 is determined by setting the open timer to, for example, 3 seconds, in advance in the PLC, and multiplying the close timer (LL close timer) by a close timer correction coefficient to obtain the "corrected LL close timer," which is set in the PLC and used for control. Corrected LL close timer = LL close timer x close timer correction coefficient The LL close timer is the time of a timer that is preset in the PLC. The opening and closing operation of the dam plate 108 is performed based on a combination of the open timer time and the "corrected LL close timer time" in the corrected LL discharge control (step S502).

[0072] The length of the close timers is in the following order: LL close timer > L close timer > M close timer > H close timer. The shorter the closing timer time, the shorter the closing time of the overflow port 102, so the discharge amount of the dried product D increases, and the amount of the processed material M in the main body shell 10 decreases.

[0073] Conventionally, in steps S101, S104, S201, S202, S301, S302, S401, S402, S501, and S502, operation is simply performed at the current value and close timer time previously set in the PLC. On the other hand, in the present invention, the apparent density of the dried product D described above is determined, and the corrected HH current value, corrected H current value, corrected M current value, corrected L current value, corrected LL current value calculated using equation (3), as well as the corrected H close timer time, corrected M close timer time, corrected L close timer time, and corrected LL close timer time calculated using equation (4), are set in the PLC, and by operating a combination of judgment control and operation control shown in Figure 9, more specifically, by operating to adjust the discharge amount of the dried product D from the main body shell 10, it becomes possible to operate while maintaining the hold amount (also called retention amount) at an appropriate state according to the apparent density of the dried product D.

[0074] In addition, if the current value I flowing to the motor 14 in step S501 is less than the corrected LL current value (if the answer is NO in S501), the process proceeds to S601, and the opening and closing operation of the weir board 108 is stopped, the overflow outlet 102 is blocked by the weir board 108, and discharge stop control is performed to prevent the dried product D from being discharged from the overflow outlet 102.

[0075] Also in step S102, if the dryer discharge side temperature T15 detected by temperature sensor 15 is equal to or lower than the predetermined temperature "L" (YES in S102), the above-described discharge stop control is performed. If the current value I flowing through the motor 14 is equal to or greater than the corrected H current value, step S104 continues, and if it becomes less than the corrected H current value, the process proceeds to step S105, and after a predetermined time has elapsed in step S105, the process returns to step S101 and the control is repeated.

[0076] As described above, according to the present invention, the controlled items of the horizontal continuous conduction heat transfer dryer 1 are changed proportionally in response to fluctuations in apparent density, so that the controlled items can be changed gradually in response to fluctuations in apparent density. As a result, the judgment and burden on the operator are reduced, and stable operation can be performed without causing clogging of the main body shell 10 with the material to be treated, or insufficient or excessive drying of the dried product D. Furthermore, the current value correction value, the closed timer time correction value, and the frequency correction value are simultaneously determined according to the apparent density measurement value V, so that the controlled elements can be corrected in a balanced manner, and the cooperating components of the horizontal continuous conduction heat transfer dryer 1 can be operated smoothly.

[0077] [Modification of apparent density measuring device] A modified example of the apparent density measuring device 2 will be described below. 10(a) is configured so that the dried product D discharged from the dried product discharge port 121 can be directly supplied into the housing 20. Specifically, an inlet 20a is formed above the inclined plate 22 of the housing 20, and a nozzle 28 for blowing air into the inside of the measuring cup 21 is provided. Air is supplied to the nozzle 28, for example, by branching off a pipeline for the carrier gas supplied to the carrier gas port 103. An exhaust port 27 for exhausting the carrier gas to the bag filter 7 is provided at the top of the housing 20 .

[0078] The apparent density measuring device 2 shown in FIG. 10(b) is configured such that the inclined plate 22 and the switching damper 23 for moving it are provided outside (above) the housing 20. These modified examples can be used when it is clear that the amount of fine powder collected by the bag filter 7 is small, and the present invention can be essentially achieved without performing measurements using the apparent density measuring device 2 in a state containing this fine powder. Alternatively, it can also be used when the apparent density of the dry product D mixed with fine powder can be calculated by measuring only the dry product D using the apparent density measuring device 2 and multiplying the measurement value by a certain coefficient. [Explanation of symbols]

[0079] D Dry product M: Material to be processed 1. Horizontal continuous conduction heat transfer dryer 10 Main body shell 100 machines 101 Inlet 101a Inlet 101b Inlet 101c Inlet 102 Overflow outlet 102b Overflow port 103 Carrier gas port 104 Exhaust port 105 Steam supply port 106 Drain port 107 Fixed weir plate 108 Weir plate 109 Air Cylinder 109a Solenoid valve 11 Multi-tube heating tube 111 Angle 112 Headboard 113 Axial Body 114 Bearing Block 115 rotary joint 115a rotary joint 115b rotary joint 116 tube bundles 117 Lifter 118 Feed feather 12 shots 121 Dry product outlet 122 rotary valve 13 Sealing mechanism 14 Motor 15 Temperature Sensor 16 Temperature Sensor 2. Apparent density measuring device 20 Case 20a Inlet 20b Outlet 21 Measuring cup 22 Inclined plate 23 Switching damper 24 cylinders 25 scraping board 26 Weighing device 27 Exhaust port 28 nozzles 3 Control Panel 41 Discharge conveyor 411 Inlet 412 Inlet 413 Outlet 414 Outlet 415 Damper 5. Dried sludge hopper 6. Material input device 61 Motor 7. Bag filter 71 Outlet

Claims

1. A heat transfer member is provided inside the main body shell, and this heat transfer member is rotated while a heating medium is flowing inside the heat transfer member. The material to be treated is placed inside the main body shell, and while the material to be treated is retained inside the main body shell, it is lifted up by a lifter provided on the side periphery of the heat transfer member. It is brought into contact with the tube bundle that constitutes the heat transfer member to promote drying, and In the operation of a horizontal continuous conduction heat transfer dryer, which transfers materials from the inlet side to the overflow outlet side and discharges them as dried products from the overflow outlet, A method for operating a horizontal continuous conduction heat transfer dryer, characterized by determining the apparent density of the dried product discharged from the overflow outlet, and proportionally varying the controlled parameters of the horizontal continuous conduction heat transfer dryer in accordance with fluctuations in this apparent density.

2. The controlled item of the horizontal continuous conduction heat transfer dryer is a "judgment control" regarding the current value of the motor that rotates the heat transfer member, and by proportionally varying the "set value" in this "judgment control", 2. The method for operating a horizontal continuous conduction heat transfer dryer according to claim 1, wherein the residence time of the material positioned within the main body shell is kept appropriate.

3. The controlled item of the horizontal continuous conduction heat transfer dryer is the "closing time" of the discharge damper that opens and closes the overflow port. By controlling this value, 2. The method for operating a horizontal continuous conduction heat transfer dryer according to claim 1, wherein the residence time of the material positioned within the main body shell is kept appropriate.

4. The controlled item of the horizontal continuous conduction heat transfer dryer is the "frequency" of the material input device for inputting the material into the main body shell. By controlling this value, 2. The method for operating a horizontal continuous conduction heat transfer dryer according to claim 1, wherein the residence time of the material positioned within the main body shell is kept appropriate.

5. A heat transfer member is provided inside the main body shell, and this heat transfer member is rotated while a heating medium is flowing inside the heat transfer member. The material to be treated is placed inside the main body shell, and while the material to be treated is retained inside the main body shell, it is lifted up by a lifter provided on the side periphery of the heat transfer member. It is brought into contact with the tube bundle that constitutes the heat transfer member to promote drying, and In the operation of a horizontal continuous conduction heat transfer dryer, which transfers materials from the inlet side to the overflow outlet side and discharges them as dried products from the overflow outlet, The apparent density of the dried product discharged from the overflow port is calculated, and the controlled items of the horizontal continuous conduction heat transfer dryer are proportionally changed according to the change in the apparent density. A method for operating a horizontal continuous conduction heat transfer dryer, characterized in that the apparent density of the dried product is determined by measuring the weight of a measuring cup filled with the dried product multiple times and using the average value of the weights.

6. 6. The method for operating a horizontal continuous conduction heat transfer dryer according to claim 5, wherein a lower limit and an upper limit are set for the apparent density, and a proportional change in a set value of a control item is reflected within the range between the lower limit and the upper limit.

7. 6. A method for operating a horizontal continuous conduction heat transfer dryer according to claim 5, wherein the fine powder discharged from the exhaust port is supplied to a measuring cup in addition to the dried product discharged from the overflow port.

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