JP6668849B2 - Powder or analysis sample supply device and powder supply method - Google Patents

Description

  The present invention relates to a powder or analysis sample supply apparatus and a powder supply method.

  2. Description of the Related Art Conventionally, in a bagging device for bagging powder such as flour, an empty bag is set in the device, weighed, and while flour is cut out from a hopper, the total weight of the bag and the flour put into the bag is measured. , And subtract the weight of the empty bag to calculate the weight of the flour put into the bag. When the calculated weight of the flour reaches the specified amount, the cutting of the flour is stopped.

  On the other hand, in an analyzer that dissolves a certain amount of powdered sample such as incinerated ash in water and analyzes the components and properties (such as alkalinity), the sample is weighed in a measuring container and put into a melting tank. Make a solution. However, in this method, by reusing the measuring container, there is a possibility that the remainder of the sample put in the measuring container for the measurement before the previous time may be mixed. For this reason, the washing and drying of the measuring container must be performed for each analysis, which complicates the operation. In order to accurately measure the sample, it is preferable that the cut-out amount of the sample is measured without passing through the measuring container, and the measured sample is directly supplied to the dissolution tank.

  As a method of measuring the cut-out amount of the powder sample, a method in which an increase in the weight of the dissolving tank while the sample is charged is used as the weight of the charged sample can be considered. However, since the dissolving tank is connected to other devices by water supply and drainage hoses, it is impossible to accurately measure the weight of the dissolving tank alone.

  On the other hand, as a method for measuring the amount of powder cut out, a loss-in-weight type feeding device, a constant feedware, a powder flow meter type, and the like are known. In these methods, since the powder supply device can be made independent of the melting tank, it is possible to measure the amount of powder cut out.

  Above all, a powder feeder of a loss-in-weight type performs replenishment and cutout of raw materials by weighing the whole raw material feeder equipped with a load cell by a weight reduction method using a scale (scale) (see Patent Document 1). . The loss-in-weight type powder supply device is said to have excellent precision in quantitatively supplying powder compared to other supply types, and is widely used when high precision is required.

  FIG. 10 is a schematic cross-sectional view of a generally widely known loss-in-weight type powder supply device 100 when viewed from the front. The powder supply device 100 receives the powder from the powder storage unit 110 that stores the powder, the powder delivery unit 120 that sends out the powder stored in the powder storage unit 110, and the powder delivery unit 120. A load measuring unit 130 for measuring a load, a control unit electrically connected to the powder sending unit 120 and the load measuring unit 130, and controlling an amount of the powder housed in the powder housing unit 110 to be sent out. 140.

  The powder delivery section 120 has a powder delivery member 121 for delivering the powder stored in the powder storage section 110 to the outside, and a driving member 122 for driving the powder delivery member 121.

  Further, the control unit 140 sends a tare cancellation command unit 141 for instructing the load measurement unit 130 to tare the load measurement unit 130, and sends the powder to the driving member 122 in response to the tare cancellation command. It has a start command means 142 for commanding the start of driving of the member 121 and a stop command means 143 for instructing the drive member 122 to stop driving the powder feeding member 121 at a predetermined timing.

  FIG. 11 is a flowchart illustrating an example of a powder supply method for supplying a predetermined amount of powder to the analyzer using the powder supply device 100 of the loss-in-weight type. When the start of powder weighing is instructed based on a program stored in the storage unit in advance or based on information input from the outside (step S101), the tare instruction unit 141 sets the load measurement unit 130 Tare is performed (step S102). The start instruction unit 142 starts driving the powder sending member 121 and starts cutting out the powder from the powder storage unit 110 in response to the instruction from the tare instruction unit 141 (step S103). The load measuring unit 130 measures the weight of the entire powder supply device 100 (the powder storage unit 110 and the powder sending unit 120) (Step S104). When it is determined that the weighing value (decrease value) measured by the load measuring unit 130 is equal to or more than the predetermined amount (Yes in step S105), the stop command unit 143 stops the rotation of the powder feeding member 121 and cuts out. The operation is stopped (Step S106), the powder measurement by the powder supply device 100 is terminated, and a powder measurement completion signal is transmitted to the analyzer to stand by (Step S107). Then, when receiving the signal indicating the end of the analysis process from the analyzer (Yes in step S108), the control unit 140 discharges the remaining powder from the powder sending unit 120 (step S109), and starts measuring the next powder. Or end a series of operations.

  However, in the powder feeder 100 of the loss-in-weight type, the powder storage unit 110 is provided between the start of the driving of the powder feeding member 121 by the start command unit 142 and the stop of the driving by the stop command unit 143. When the amount of the stored powder decreases, the powder is supplied to the powder storage unit 110 by dropping the powder toward the powder storage unit 110. When powder is replenished, an impact load generated by dropping the powder is added to an original load generated by replenishing the powder. Therefore, even with the loss-in-weight type powder supply device 100 which is considered to have relatively high accuracy, there remains a problem in improving the measurement accuracy.

  Therefore, various techniques have been proposed to minimize disturbance caused by impact caused by falling of the powder (see Patent Document 2).

  It has also been proposed that a loss-in-weight type feeding device is installed such that the weight of a motor driving a feeding device (transport and discharge device) cannot be detected by a load cell serving as a load measuring unit (see Patent Document 3). ). This supply unit is attached to the common base on which the load cell is mounted so that the motor and drive unit are separated from the screw feeder and the weight of the motor and drive unit is not applied to the load cell. The rotation force is transmitted to the screw feeder by a non-contact magnet coupling so as not to act.

Utility Model Registration No. 3035058 JP 2015-225018 A JP 2012-168147 A

  However, when the powder supply device 100 of the loss-in-weight type is adopted and the load of the entire powder supply device 100 (including the drive motor and the like) is applied to the load measuring unit 130, the powder is supplied. In addition to the above, even when the start command unit 142 instructs the driving member 122 to start driving the powder feeding member 121, a load different from the original load is applied to the load measuring unit 130. In addition, it has been found that weighing errors can occur.

  As described in Patent Literature 1, if the powder supply device 100 is a bag filling device that packs raw materials, weighing is performed without an interval between weighing operations. The frequency at which the start of the driving of the powder feeding member 121 is instructed to the powder feeding member 121 is low, and the measurement error at the start of the driving can be ignored.

  On the other hand, when the object to be measured is a powder supplied to the analyzer such as incineration ash, the cutting device is stopped at each weighing operation, and an interval corresponding to the time required for analysis is performed at each weighing operation. Provided. Therefore, the drive member 122 is frequently instructed to start driving the powder delivery member 121, and the measurement error at the start of driving cannot be ignored.

  In addition, incineration ash and the like are used for analyzing components and properties (such as alkalinity) by dissolving in water, so that the measurement error at the start of driving cannot be ignored in terms of improving the accuracy of the analysis result.

  In the device described in Patent Document 3, since the load of the drive motor is not detected by the load cell serving as the load measuring unit, it is considered that no weighing error occurs at the start of driving. However, the mechanical structure itself of the device is updated. Required and can be costly. In order to provide the apparatus at low cost, it is preferable to obtain high analysis accuracy by changing the program stored in the control unit 140 without updating the mechanical structure itself of the apparatus.

  The shape of the load measuring unit 130 is not particularly limited. However, in order to suppress the cost of the powder supply device 100, one end is provided to be able to measure a load applied from the powder sending unit 120, and the other end is cantilever-shaped. A cantilever-shaped load cell fixed to the main body is often used.

  As a method of avoiding the measurement error, it is conceivable that the shape of the load measuring unit 130 is not a cantilever beam but a doubly supported shape. However, when the shape is made to be a two-sided shape, the cost of the powder supply device 100 becomes higher than when the shape is a cantilever shape.

  The present invention has been made in view of the above circumstances, and even if the target is powder to be supplied to the analyzer, regardless of the measurement error at the start of driving the powder delivery member, the supply amount of powder It is an object of the present invention to provide a low-cost powder supply device capable of accurately measuring the amount of powder.

  The present inventors have intensively studied to solve the above-mentioned problem. As a result, it is presumed that the reason why a measurement error may occur when the driving of the powder feeding member 121 is started is as follows.

  As described with reference to FIG. 10, in general, the powder supply device 100 includes a powder delivery member 121 including a rotating member such as a screw below the powder storage unit 110 that stores powder. A part 120 is provided, and the powder in the powder storage part 110 is cut out by the rotation of the powder delivery member 121.

  FIG. 12 is an example of a schematic diagram illustrating the internal configuration of the driving member 122 and the load measuring unit 130 when the powder supply device illustrated in FIG. 10 is viewed from the left side. The driving member 122 includes a bearing portion 123 that accommodates the rotating shaft 121A of the powder delivery member 121, a driving portion 124 that is disposed on a side of the bearing portion 123, and that accommodates a driving motor, a bearing portion 123, and a driving portion 124. And a belt chain 125 connecting the two.

  When the driving of the driving member 122 is to be started, the belt chain 125 is tightened, and the driving shaft 126 extending from the main body of the driving motor starts to rotate in the direction of arrow A in the drawing. The powder is transmitted to the rotation shaft 121A via the rotation shaft 125, and the powder delivery member 121 is driven to rotate. However, at this time, the distance X between the rotating shaft 121A and the drive shaft 126 is slightly reduced in the direction of arrow B, and the position of the center of gravity of the powder delivery unit 120 moves as shown by arrow C in the figure, and the powder delivery is performed. The portion 120 is distorted.

  The load cell, which is one mode of the load measuring unit 130, has one end 130 </ b> A capable of measuring a load applied from the powder sending unit 120, and the other end 130 </ b> B fixed in a cantilever shape. Therefore, the load measuring unit 130 detects the movement of the position of the center of gravity in the longitudinal direction, and changes the weighed value by detecting the movement.

  Then, the present inventors start the driving of the driving member 122 once, not before the driving of the driving member 122 is started, and the timing for performing the tare of the load measuring unit 130 is measured by the load measuring unit 130. By setting the timing after the timing at which the amount of change in the load becomes the maximum for the first time, it is found that the supply amount of the powder can be accurately measured regardless of the measurement error at the start of driving of the driving member 122. It was completed. More specifically, the present invention provides the following.

  (1) The present invention provides a powder accommodating section for accommodating a powder, a powder delivering section for delivering the powder contained in the powder accommodating section to the outside, A load measuring unit that measures a load applied from the body sending unit, and an amount of the powder that is electrically connected to the powder sending unit and the load measuring unit and that is sent out of the powder stored in the powder storing unit. A control unit for controlling the power supply unit, wherein the powder delivery unit includes a powder delivery member that delivers the powder stored in the powder storage unit to the outside, and a driving member that drives the powder delivery member. The control unit may further include a start command unit that instructs the drive member to start driving the powder delivery member, and a start command unit that starts drive of the powder delivery member. Time longer than the time required for the change in load measured by When the time has elapsed, stop command means for instructing the drive member to stop driving the powder feeding member, start of drive by the start command means, and stop of drive by the stop command means are performed. In this case, the load measuring unit, tare instructing means for instructing the tare of the load measuring unit, and, in response to the tare instruction, the powder sending member with respect to the drive member And a start re-instruction means for instructing the start of driving of the powder supply again.

  (2) Further, the present invention further includes a storage unit in which a predetermined time equal to or longer than a time required until a change amount of the load measured by the load measuring unit reaches a local maximum for the first time is further stored. It is a powder supply apparatus of description.

  (3) Further, the present invention provides a powder supply device according to any one of (1) and (2), and a dissolving unit that contains a solvent and dissolves the powder sent from the powder sending unit. And an analysis sample take-out unit for taking out a dissolved substance of the powder by the solvent as an analysis sample, wherein the control unit sends the powder from the powder sending unit to the melting unit from the measurement result of the load measurement unit. Weight measuring means for measuring the weight of the powder obtained, and again instructing the start of the driving of the powder feeding member by the start re-instruction means, so that the weight measured by the weight measuring means becomes a predetermined value. An analysis sample supply device having stop re-instruction means for instructing the drive member to again stop the driving of the powder delivery member when the drive member is reached.

(4) Further, according to the present invention, the powder delivery member includes a screw that rotates around a predetermined rotation axis, and the control unit is housed in the powder housing unit with respect to the drive member. A powder discharger that instructs the screw to rotate in a direction opposite to a direction in which the powder is sent out, and discharges the powder remaining inside the powder delivery member to a location different from the melting section. Means, wherein the rotation speed of the screw from a command to start rotation of the screw by the start command means to a command to stop rotation of the screw by the stop command means is R ₁ (times / second). The rotation time of the screw during that time is T ₁ (second), and the reverse rotation speed of the screw is R ₂ (times / second) while the powder is being discharged by the powder discharging means, The said desk in the meantime When the reverse rotation time of-menu to T _{2 (seconds),} satisfy Formula (1), an analytical sample supply apparatus according to (3).
0.01 ≦ T ₁ ≦ R ₂ × T ₂ ÷ R ₁ (1)

(5) In the present invention, the reverse rotation time of the screw required for discharging all the powder remaining inside the powder delivery member by the powder discharging means is T ₂₀ (seconds). The analytical sample supply device according to (4), wherein the following expression (2) is satisfied.
T ₂ ≦ T ₂₀ (2)

(6) The present invention is also a powder supply method for supplying a predetermined amount of powder from a powder supply device, wherein the powder supply device includes: a powder storage unit for storing powder; A powder delivery unit that sends out powder stored in the body storage unit, and a load measurement unit that is fixed in a cantilever shape and measures a load applied from the powder delivery unit,
The method requires a driving start step of starting driving of the powder feeding member, and a start of driving of the powder feeding member until the amount of change in the load measured by the load measuring unit reaches a local maximum for the first time. When a predetermined time equal to or longer than a predetermined time has elapsed, a drive stopping step of stopping the driving of the powder feeding member, a taring step of taring the load measuring unit, and after the taring, the powder feeding is performed. And a drive restarting step of restarting the driving of the member.

  (7) Further, in the present invention, prior to the driving start step, the driving of the powder feeding member is started, and a change with time of a load change measured by the load measuring unit is measured. The powder supply method according to (6), further comprising: a setting step of setting the predetermined time in advance from the above.

  ADVANTAGE OF THE INVENTION According to this invention, even if the object is a powder supplied to an analyzer, it is possible to accurately measure the supply amount of the powder regardless of a measurement error at the time of starting the driving of the powder delivery member. A body supply device can be provided. The shape of the load measuring section is a cantilever shape, and the mode of the control operation by the control section is changed without changing the existing apparatus configuration. Another effect is that the apparatus can be provided at low cost.

It is an example of a sectional view when the powder supply device concerning this embodiment is seen from the front. It is an example of the schematic diagram which shows the drive member and the internal structure of a load measuring part when the same powder supply apparatus is seen on the left side surface. FIG. 3 is a block diagram illustrating an electrical configuration of a powder sending unit, a load measuring unit, and a control unit in the powder supply device. It is an example of a schematic diagram when the analysis sample supply device according to the present embodiment is viewed from the front. It is a flowchart which shows an example of the powder supply method which supplies fly ash (sample) to an analyzer by an analysis sample supply device. It is a graph which shows the change of the weighing value of the load cell until about 15 minutes have passed since the drive of a powder delivery part started. FIG. 7 is an enlarged view showing a state immediately before and immediately after driving of a powder feeding section is started in FIG. 6. It is a graph which shows the fluctuation | variation of the measured value of a load measurement part when a powder delivery member of a powder supply apparatus is driven for 2 seconds. 6 is a graph showing a coefficient of variation between an example and a comparative example. FIG. 1 is a schematic cross-sectional view of a generally known loss-in-weight type powder supply device when viewed from the front. 5 is a flowchart illustrating an example of a powder supply method for supplying a predetermined amount of powder to an analyzer using a loss-in-weight type powder supply device. It is an example of the schematic diagram which shows the internal structure of a drive member and a load measurement part when the powder supply apparatus shown in FIG. 10 is left side view.

  Hereinafter, embodiments of the present invention will be described, but this does not limit the present invention.

<Powder supply device>
FIG. 1 is an example of a cross-sectional view when the powder supply device according to the present embodiment is viewed from the front. FIG. 2 is an example of a schematic diagram showing an internal configuration of a driving member and a load measuring unit when the powder supply device is viewed from the left side. As shown in FIG. 1, a powder supply device 1 according to the present embodiment includes a powder storage unit 10 that stores powder, and a powder that cuts out powder stored in the powder storage unit 10 and sends the powder to the outside. A body sending section 20, a load measuring section 30 for measuring a load between the powder containing section 10 and the powder sending section 20, and a powder containing section electrically connected to the powder sending section 20 and the load measuring section 30; And a control unit 40 for controlling the amount of the powder contained in the sheet 10 to be sent out.

  The powder supply device 1 measures the load between the powder storage unit 10 and the powder sending unit 20 by the load measuring unit 30 and measures the reduction amount of the powder sent out to the outside by the powder sending unit 20. It is a loss-in-weight formula for calculating a powder supply amount.

  In the powder supply device 1 according to the present embodiment, the type of the target powder is not particularly limited. For example, flour, cement, a powdery analysis sample, a powdery drug and the like can be mentioned.

[Powder container 10]
As shown in FIG. 1, the powder storage unit 10 is formed in a funnel shape, has an opening 10 </ b> A facing upward in the direction of gravity, and communicates with the powder delivery unit 20 below. The powder introduced from the opening 10A falls according to gravity and is cut out by the predetermined amount toward the powder delivery unit 20.

[Powder delivery unit 20]
The type of the powder delivery section 20 is not particularly limited, and examples thereof include a screw feeder and an auger-type feeder. In particular, the powder delivery unit 20 is preferably a screw feeder because the powder can be continuously transported at a constant flow rate and the transport direction can be easily changed.

  Hereinafter, a case where the powder delivery unit 20 is a screw feeder will be described. As shown in FIG. 1, the powder delivery unit 20 includes a cylinder 21, a screw 22 housed in the cylinder 21, and a driving member 23 that drives the screw 22.

[Cylinder 21]
The cylindrical body 21 has a shape in which an L-shape and an inverted L-shape are combined, and is formed such that the longitudinal direction is horizontal. At the end of the L-shaped portion, an inlet 21A is formed upward in the direction of gravity, and the upper side in the direction of gravity communicates with the powder container 10. An outlet 21 </ b> B is formed downward at the end of the inverted L-shaped portion, so that the powder that has passed through the inside of the cylinder 21 can be sent out of the cylinder 21.

[Screw 22]
The screw 22 has a rotating shaft 221 and a wing portion 222 formed in a spiral with the rotating shaft 221 as a central axis. The screw 22 starts to rotate when the driving member 23 operates, and continuously feeds the powder toward the outlet 21B of the cylindrical body 21 at a constant flow rate while pressing the powder flowing from the inlet 21A against the wing portion 222. .

  In this embodiment, when the screw 22 rotates forward, the screw 22 conveys the powder from the inlet 21A to the outlet 21B, and when the screw 22 rotates reversely, the screw 22 moves the powder from the outlet 21B to the inlet 21A. The description will be made assuming that they are transported.

  In the present embodiment, the screw 22 is described as having one screw, but is not limited to this. The number of screws 22 may be plural. Although not shown, the powder delivery unit 20 is provided with a cutting screw that cuts out the powder in the powder storage unit 10 from the inlet 21A toward the inside of the cylindrical body 21, and is provided below the cutting screw. A recovery screw that recovers the cut powder and conveys the powder toward the outlet 21B may be provided. The powder delivery unit 20 may be provided with a rectangular frame-shaped rotating member or the like for dispersing the powder between the powder storage unit 10 and the screw 22.

[Drive member 23]
FIG. 2 is an example of a schematic diagram illustrating an internal configuration of the driving member 23 and the like when the powder supply device 1 illustrated in FIG. 1 is viewed from the left side. The driving member 23 includes a bearing portion 231 that accommodates the rotation shaft 221 of the screw 22, a driving portion 232 that is disposed on a side of the bearing portion 231, and that accommodates a driving motor (not shown), and a driving portion that drives the bearing portion 231. And a belt chain 233 connecting the first and second parts 232 to each other.

  When the drive member 23 receives a drive start command from the control unit 40, the drive member 23 starts operating the drive motor. Then, the belt chain 233 is tightened, and the rotation of the drive shaft 234 extending from the main body of the drive motor is started. The rotation of the drive shaft 234 is transmitted to the rotation shaft 221 via the belt chain 233, and the screw 22 rotates. Driven.

[Load measuring unit 30]
The load measuring unit 30 measures a load applied from the powder sending unit 20. Examples of the load measuring unit 30 include a Roberval type and a shear type (shear type). Above all, a Roberval load cell is preferable from the viewpoint of accuracy.

  Hereinafter, a case where the load measuring unit 30 is a Roberval type load cell will be described. As shown in FIG. 2, the load measuring unit 30 is configured to include a metal such as an aluminum alloy or stainless steel, and measures a square rod-shaped or thick plate-shaped strain-generating body 31 and a strain generated in the strain-generating body 31. And a strain gauge 32.

[Strain body 31]
The strain element 31 is configured such that the longitudinal direction is the horizontal direction and the short direction is the direction of gravity. One end 31 </ b> A of the strain body 31 extends upward in the direction of gravity and contacts the powder delivery unit 20. The other end 31B of the flexure element 31 extends downward in the direction of gravity and is fixed in a cantilever shape. A recess 31 </ b> C is provided substantially at the center of both long sides of the strain body 31.

  A roberval mechanism 310 is formed at a location substantially at the center of the strain body 31 where the upper and lower recesses 31C are provided. The roberval mechanism 310 is formed at both ends in the longitudinal direction of the elongated hole 310A and the elongated hole 310A extending in the longitudinal direction of the strain body 31, and the length of the hole in the short direction of the strain body 31 is the same in the same direction. It is configured to include substantially elliptical elliptical holes 310B and 310C larger than the size of the hole 310A.

  Since the recess 31C, the long hole 310A, and the elliptical holes 310B and 310C are provided substantially at the center of the strain body 31, the thickness of the metal in the short direction substantially at the center of the strain body 31 in the longitudinal direction is reduced. It is shorter than the thickness of the metal in the lateral direction on both sides in the longitudinal direction of the strain body 31. In particular, since the size of the elliptical holes 310B and 310C in the short direction of the strain element 31 is larger than the size of the long hole 310A in the same direction, the position of the elliptical holes 310B and 310C in the short direction is provided. The thickness of the metal is the smallest in the entire strain body 31. The other end 31B of the flexure element 31 is fixed in a cantilever shape. Therefore, when a load is applied to one end 31A of the cantilever-supported flexure element 31, the flexure element 31 elastically bends and deforms in the direction in which the one end 31A goes down, and the upper and lower surfaces of the flexure element 31, particularly Roberval. A tensile strain or a compressive strain occurs near the mechanism 310.

[Strain gauge 32]
The strain gauge 32 is affixed to the thinnest portion formed by the elliptical holes 310 </ b> B and 310 </ b> C of the roberval mechanism 310 in the recess 31 </ b> C provided substantially at the center of the strain body 31.

  As described above, when a load is applied to one end 31 </ b> A of the cantilever-supported strain generating element 31, a tensile strain or a compressive strain is generated particularly near the roberval mechanism 310. Then, the tensile strain or the compressive strain is detected by the strain gauges 32A, 32B, 32C, 32D. And the magnitude of the strain corresponds to the applied load. Therefore, the load measuring unit 30 enables measurement of the load applied from the powder sending unit 20.

  In addition, a load cell of a doubly supported type in which the flexure element 31 is supported at both ends is also known. Is considered to be small, but is not preferable in terms of cost and accuracy.

  As described above, in the present embodiment, the direction of movement of the position of the center of gravity of the powder delivery unit 20 due to the distortion of the powder delivery unit 20 is the same as the longitudinal direction of the load measurement unit 30 (load cell). When the screw 22 is driven, the load measuring unit 30 is easily affected by the distortion of the powder sending unit 20. On the other hand, when the moving direction of the center of gravity of the powder delivery unit 20 is orthogonal to the longitudinal direction of the load measurement unit 30 (load cell), the load measurement unit 30 is not easily affected by the distortion of the powder delivery unit 20. Conceivable. However, with such a configuration, every time powder is discharged from the outlet 21B at the end of the powder delivery unit 20 in the longitudinal direction (the rotation axis direction of the screw 22), the vibration generated by the reaction is generated by the load measurement unit. 30 may affect the measurement accuracy. Therefore, it is preferable that the longitudinal direction of the powder delivery unit 20 and the longitudinal direction of the load measuring unit 30 (load cell) are not the same as in the powder supply device 1 according to the present embodiment.

[Control unit 40]
Return to FIG. The control unit 40 is electrically connected to the powder sending unit 20 and the load measuring unit 30 to exchange signals, and controls the amount of the powder stored in the powder storage unit 10 to be sent out. . The control unit 40 includes an arithmetic processing unit including a CPU (Central Processing Unit) 41, a storage unit 42, a timer 43, and the like.

[CPU 41]
The CPU 41 is a central processing unit, and executes various processes according to a program.

[Storage unit 42]
The storage unit 42 stores control programs and the like for various processes executed by the CPU 41.

  In order to determine the timing at which the load measurement unit 130 performs taring, the storage unit 42 is instructed to start driving the powder feeding unit 20 in addition to the control program. It is preferable that a predetermined time until a command to temporarily stop the driving of the unit 20 is stored in advance.

  As described above, when the driving of the screw 22 is started, the powder delivery unit 20 is distorted, and the load measured by the load measurement unit 30 changes. Therefore, prior to using the powder supply device 1, the change with time of the change measured by the load measuring unit 30 is measured, and from the measurement result, the change in the load measured by the load measuring unit 30 is determined. It is preferable that a time required for the first time to reach the maximum be found, and a predetermined time longer than that time be stored in the storage unit 42 in advance.

  The lower limit of the predetermined time is not particularly limited as long as it is equal to or longer than the time required until the amount of change in the load measured by the load measuring unit 30 reaches a local maximum for the first time after the start of driving of the powder feeding unit 20 is instructed. If the predetermined time is too short, the supply amount of the powder may not be accurately measured, which is not preferable.

  The upper limit of the predetermined time is not particularly limited. However, in order to prevent the powder in the cylindrical body 21 from being discharged from the outlet 21B before taring, it is preferable that the time from the timing when the variation first reaches a maximum is shorter, and the variation first reaches a maximum. It is particularly preferable that the timing be immediately after the timing.

[Timer 43]
The timer 43 is provided so as to be able to measure an elapsed time from when the CPU 41 instructs the start of the driving of the powder feeding section 20. Based on the value measured by the timer 43, it can be determined whether or not the elapsed time since the CPU 41 instructed the start of the driving of the powder feeding section 20 has exceeded a predetermined time stored in the storage section 42.

  Turning to FIG. 3, the function of the control unit 40 will be described with reference to a block diagram of the electrical configuration of the powder sending unit 20, the load measuring unit 30, and the control unit 40 in the powder supply device 1.

  The control unit 40 functions as a start command unit 40A, a stop command unit 40B, a tare cancellation command unit 40C, and a start re-command unit 40D. In addition, it is preferable that the control unit 40 also functions as a weight measuring unit 40E, a stop re-instruction unit 40F, and a powder discharging unit 40G. The weight measuring means 40E, the stop re-instruction means 40F, and the powder discharging means 40G will be described later.

[Start command means 40A]
The start instruction unit 40A instructs the drive member 23 to start driving the screw 22 in response to a command operation or the like from the administrator of the powder supply device 1. The mode of the command operation is not particularly limited, and includes, for example, operation of a keyboard (not shown), operation of a mouse (not shown), operation of a touch panel (not shown), and the like. When a keyboard or the like is operated, a sensor (not shown) detects the operation, and a command signal is transmitted from the sensor to the CPU 41 indicating that the sensor has detected that the administrator has performed a command operation. Then, in response to receiving the command signal, the CPU 41 transmits a start command signal for instructing the drive member 23 to start driving the screw 22.

[Stop command means 40B]
When the start command means 40A transmits the start command signal, the timer 43 starts measuring time. The stop command means 40B transmits a stop command signal for commanding the driving member 23 to stop driving the screw 22 when the time measured by the timer 43 reaches a predetermined time stored in the storage unit 42 in advance. Then, the driving of the screw 22 is stopped. The “predetermined time” will be described later.

[Tare instruction unit 40C]
When the stop command unit 40B transmits the stop command signal, the tare cancellation command unit 40C transmits a tare cancellation command signal for instructing the load measuring unit 30 to tare. When the taring instruction unit 40C transmits the tare signal, a small amount of powder exists inside the cylindrical body 21 of the powder supply device 1, but the powder is not discharged to the outside.

[Start re-instruction means 40D]
When the tare cancellation command unit 40C transmits the tare cancellation command signal, the start re-instruction unit 40D transmits a drive start re-instruction signal for instructing the drive member 23 to start driving the screw 22 again, and drives the screw 22. To start.

  By the way, as described in the related art with reference to FIG. 12, when the driving member 23 (the screw 22) starts driving, the powder delivery unit 20 is distorted. When the driving member 23 stops driving, although the distortion of the powder feeding section 20 is reduced, it takes a long time (for example, about 15 minutes) until the measured value of the load measuring section 30 is stabilized.

  Therefore, the processing time of the control unit 40 between the time when the stop command means 40B transmits the stop command signal and the time when the tare cancellation command means 40C transmits the tare cancellation command signal is equal to the processing time of the drive member 23 and the load measurement unit 30. Preferably, it is as short as possible, as long as it does not affect operation. Specifically, the processing time of the control unit 40 between the time when the stop command means 40B transmits the stop command signal and the time when the tare cancellation command means 40C transmits the tare cancellation command signal may be 10 seconds or less. Preferably, it is 1 second or less.

  As described above, in the powder supply device 1, the screw 22 is driven, and the taring is performed in a state in which the powder delivery unit 20 is distorted. The influence on the value can be offset, and the load measuring unit 30 can accurately measure the weight loss of the powder supply device 1. Therefore, the powder supply device 1 according to the present embodiment can accurately supply the powder amount regardless of the measurement error at the time of starting the driving of the screw 22, even if the target is the powder supplied to the analysis device. Can be weighed. In the powder supply device 1, the shape of the load measuring unit 30 is a cantilever shape, and by changing the mode of the control operation by the control unit 40, the load measurement by the distortion of the powder sending unit 20 is performed. Since the influence of the unit 30 on the measured value is offset, the cost is lower than in the case where the existing device configuration is changed.

<Analysis sample supply device 50>
The powder supply device 1 according to the present embodiment is preferably used when the driving start of the screw 22 is frequently instructed.

  For example, when the powder to be supplied is an analysis sample to be supplied to the analyzer, the screw 22 is stopped at each weighing operation, and an interval corresponding to the time required for analysis is provided at each weighing operation. For this reason, the start of driving of the screw 22 is frequently instructed, and the measurement error at the start of driving cannot be ignored.

  Therefore, the powder to be supplied is preferably an analysis sample supplied to the analyzer.

  Fly ash and the like are examples of the powder that is the analysis sample. In general, exhaust gas containing hydrogen chloride and sulfur oxides generated in combustion facilities such as municipal solid waste incinerators, industrial waste incinerators, power boilers, carbonization furnaces, and private factories is treated with an alkaline agent such as calcium hydroxide. After that, it is discharged from the chimney via a dust collector such as a bag filter. On the other hand, the fly ash collected by the dust collector contains harmful heavy metals such as lead and copper. The heavy metals are stabilized by a heavy metal fixing agent, and then disposed of in landfill. Since the properties (type and content) of heavy metals in fly ash vary depending on the type of waste to be incinerated, it is necessary to change the amount of heavy metal fixing material added in fly ash. For this reason, a predetermined amount of fly ash is taken out as a sample, supplied to the analyzer, and the appropriate amount of the heavy metal fixing material added to the entire fly ash is determined.

  Hereinafter, an example of the analysis sample supply device 50 according to the present embodiment will be described with reference to FIG. FIG. 4 is an example of a schematic diagram when the analysis sample supply device 50 according to the present embodiment is viewed from the front. In FIG. 4, the same members as those described above are denoted by the same reference numerals, and description thereof will be omitted.

  The analysis sample supply device 50 includes, in addition to the powder supply device 1 described above, a dissolving unit 51 that accommodates a solvent and dissolves powder serving as a sample that is sent from the powder sending unit 20, An analysis sample extracting unit 52 that extracts a sample solution as an analysis sample.

(Melting part 51)
The dissolving section 51 includes a dissolving tank 51A that contains a solvent and receives the powder sent from the powder sending section 20, and the solvent contained in the dissolving tank 51A and the powder sent from the powder sending section 20. And a stirrer 51B for stirring.

  The positional relationship between the powder supply device 1 and the dissolving section 51 is not particularly limited. However, in the dissolving tank 51A, the opening of the dissolving tank 51A is set in order to easily receive the powder sent from the powder sending section 20. It is preferable that it is immediately below the outlet 21B of the body sending section 20. And the powder supply apparatus 1 may be arrange | positioned on the gantry 60 as needed.

  The dissolving section 51 includes a predetermined amount of the sample supplied from the powder sending section 20 into the dissolving tank 51A via the outlet 21B, and a predetermined amount of pure water supplied into the dissolving tank 51A from a water supply section (not shown). Are stirred and mixed by a stirrer 51B to prepare a sample solution. If necessary, the dissolving section 51 is provided with a measuring instrument or the like for measuring the dissolution-reduction potential and pH of the sample solution in the dissolving tank 51A.

[Analysis sample removal unit 52]
The analysis sample extracting unit 52 is, for example, a pump and has a function of extracting a predetermined amount of the sample solution in the dissolving tank 51A. The sample solution taken out by the analysis sample taking out section 52 is supplied to the analyzer 70.

[Analyzer 70]
In the analyzer 70, the analysis of the sample solution is performed. The type of the analyzer 70 is not particularly limited, and may be appropriately selected depending on the properties of the sample. If the sample is fly ash, an alkalinity analyzer, a fluorescent X-ray analyzer, an inductively coupled plasma emission spectrometer, a high-resolution gas chromatograph mass spectrometer, or the like can be used.

[Control unit 40]
Next, the configuration of the control unit 40 in the case where the powder supply device 1 is one component of the analysis sample supply device 50 will be described with reference to FIGS. 3 and 4. The control section 40 is electrically connected to the melting section 51 and the analyzer 70 in addition to the powder sending section 20 and the load measuring section 30 to exchange signals. Thereby, the control unit 40 can receive a signal indicating the measurement result of the dissolution-reduction potential, pH, and the like of the sample solution in the dissolving unit 51, and a signal indicating the progress of the analysis in the analyzer 70 and the analysis data.

  The control unit 40 has a weight measuring unit 40E and a stop re-instruction unit 40F in addition to the start instruction unit 40A, the stop instruction unit 40B, the tare cancellation instruction unit 40C, and the start re-instruction unit 40D. Although not an essential component, the control unit 40 preferably has a powder discharging means 40G.

[Weight measuring means 40E]
The load measuring unit 30 transmits the measurement result to the control unit 40, and in response to the control unit 40 receiving the measurement result, the weight measuring unit 40E determines from the measurement result of the load measurement unit 30 that the powder is The weight sent from the sending section 20 to the melting section 51 is measured.

[Stop re-instruction means 40F]
The stop re-instruction means 40F sets the weight measured by the weight measuring means 40E to a predetermined value (for preparing the sample solution in the dissolving section 51) after the start re-instruction means 40D instructs the start of driving of the screw 22 again. When the required powder weight has been reached, a stop re-command signal is sent to the driving member 23 to stop driving the screw 22 again.

  In the analytical sample supply device 50 having the above-described configuration, as described above, a predetermined amount of the sample accurately measured by the control unit 40 is supplied to the dissolving unit 51, so that the analysis device 70 accurately analyzes the properties of the sample. It is possible.

[Powder discharging means 40G]
The powder discharging means 40G instructs the driving member 23 to rotate the screw 22 in a direction opposite to the direction in which the powder stored in the powder storing unit 10 is sent out, and the inside of the cylindrical body 21 is controlled. Has a function of discharging the powder remaining in the container to a place different from the melting section 51.

  In the analytical sample supply device 50 having the above configuration, if the sample is supplied to the dissolving unit 51 before the taring of the load measuring unit 30 is instructed by the taring instruction unit 40C, the weight of the sample is reduced by the weight measuring unit 40E. It is difficult to measure accurately. Therefore, it is preferable that the control unit 40 further includes a powder discharging unit 40G.

  The different location is not particularly limited as long as it is different from the exit 21B. For example, it may be the powder container 10 or a discharge port (not shown) separately provided in the cylindrical body 21.

Then, the control unit 40 sets the rotation speed of the screw 22 to R ₁ (times / second) from a command to start the rotation of the screw 22 by the start command unit 40A to a command to stop the rotation of the screw 22 by the stop command unit 40B. The rotation time of the screw 22 during that time is T ₁ (second), and the reverse rotation speed of the screw 22 during the discharge of fly ash by the powder discharge means 40G is R ₂ (times / second), When the reverse rotation time of the screw 22 during that time is T ₂ (seconds), it is preferable to control the driving member 23 so as to satisfy the following expression (1).
0.01 ≦ T ₁ ≦ R ₂ × T ₂ ÷ R ₁ (1)

Further, when the reverse rotation time of the screw 22 required to discharge all the sample remaining in the cylindrical body 21 by the powder discharging means 40G is set to T ₂₀ (seconds), the control unit 40 uses the following equation (2). ) Is more preferably satisfied.
T ₂ ≦ T ₂₀ (2)

  Thus, even if the screw 22 is rotated forward by the start command unit 40A before the tare cancellation of the load measuring unit 30 is commanded by the tare command unit 40C, the sample in the powder delivery unit 20 is transmitted from the delivery port 24. It is prevented from being supplied to the melting tank 3. Thus, the weight of the sample can be accurately measured by the weight measuring unit 40E.

<Powder supply method>
Next, a powder supply method according to the present embodiment will be described.

  The powder supply method according to the present embodiment is a powder supply method for supplying a predetermined amount of powder from the powder supply device 1 described above, and includes a drive start that starts driving a screw 22 that is a powder delivery member. After the start of the process and the driving of the screw 22, the driving for stopping the driving of the screw 22 when a predetermined time equal to or longer than the time required for the amount of change in the load measured by the load measuring unit 30 to reach the maximum for the first time has elapsed. The method includes a stopping step, a taring step for taring the load measuring unit 30, and a driving restarting step for restarting the driving of the screw 22 after taring.

  Further, the powder supply method according to the present embodiment starts the driving of the screw 22 prior to the driving start step, measures the time-dependent change in the amount of change in the load measured by the load measuring unit 30, and obtains the measurement result. Preferably, the method further includes a setting step of setting a predetermined time equal to or longer than a time required until the amount of change in the load measured by the load measuring unit 30 reaches a local maximum for the first time.

  According to the powder supply method according to the present embodiment, as described above, even if the target is the powder to be supplied to the analyzer 70, regardless of the measurement error at the start of driving the screw 22, the powder is supplied. The supply amount can be accurately measured.

  Hereinafter, a powder supply method for supplying fly ash (sample) as powder to the melting unit 51 and performing analysis by the analyzer 70 will be described based on a flowchart shown in FIG.

  First, the control unit 40 receives an instruction signal regarding the start of the measurement of a sample based on a program stored in the storage unit 42 in advance or based on information input from the outside (step S1).

  Next, the start instruction means 40A transmits a drive start signal for instructing the drive member 23 to start driving (forward rotation) of the screw 22, and starts cutting out the sample from the powder storage unit 10 that stores the sample. (Driving start step / step S2).

  Next, the control unit 40 refers to the measured value of the timer 43, and determines whether or not a predetermined time stored in the storage unit 42 has elapsed after instructing the start of driving of the drive member 23 (step S3). In the process of step S3, if the control unit 40 determines that the predetermined time has elapsed (YES in step S3), the control unit 40 shifts the process to step S4. On the other hand, when the control unit 40 determines that the predetermined time has not elapsed in the process of step S3 (NO in step S3), the control unit 40 repeats the process of step S3.

  In the case of a YES determination in step S3, the stop command means 40B transmits a drive stop signal for instructing the drive member 23 to stop driving the screw 22, and stops cutting out the sample (drive stop step / step S4). .

  Next, the taring means 40C transmits a tare cancellation command signal to the load measuring unit 30 and instructs the load measuring unit 30 to perform a tare subtraction (tare subtraction step / step S5).

  Next, the start re-instruction means 40D transmits a start re-instruction signal for instructing the drive member 23 to start driving the screw 22 again in accordance with the tare cancellation instruction signal from the tare cancellation means 40C (drive restart). Process / Step S6). Thus, the cutting of the sample from the powder storage unit 10 is started again, and the sample cut from the powder storage unit 10 is supplied to the melting unit 51 at a constant flow rate.

  Next, the load measuring unit 30 measures the load applied from the powder sending unit 20 and transmits a signal indicating the measurement result to the control unit 40. And the control part 40 receives the signal transmitted from the load measuring part 30 (step S7).

  Next, the control unit 40 determines whether or not the weighing value (decrease value) of the load measuring unit 30 is equal to or more than a predetermined amount (step S8). The predetermined amount is not particularly limited as long as it is a predetermined setting value. For example, when the powder is an analysis sample, the predetermined amount is the weight of the powder required for analyzing the sample.

  In the process of step S8, when the control unit 40 determines that the weighed value (decrease value) of the load measuring unit 30 is equal to or more than the predetermined amount (YES in step S8), the control unit 40 proceeds to step S9. Transfer to On the other hand, in the process of step S8, when the control unit 40 determines that the weighed value (decrease value) of the load measuring unit 30 is not equal to or more than the predetermined amount (in the case of NO determination in step S8), the control unit 40 The process proceeds to step S7, and the processes in steps S7 and S8 are repeated.

  In the case of a YES determination in step S8, the stop re-instruction means 40F transmits a stop re-instruction signal for instructing the drive member 23 to stop driving the screw 22 again (step S9). The driving member 23 stops the cutting operation in response to receiving the stop re-command signal.

  Next, the control unit 40 transmits a sample weighing completion signal to the dissolving unit 51, temporarily ends the sample weighing, and stands by (step S10).

  Next, the controller 40 determines whether or not the analysis by the analyzer 70 has been completed (step S11). This process is performed by the control unit 40 determining whether or not an analysis end signal has been received from the analyzer 70. In the process of step S11, when the control unit 40 determines that the analysis by the analysis device 70 has been completed (YES in step S11), the control unit 40 shifts the process to step S12. On the other hand, in the process of step S11, when the control unit 40 determines that the analysis by the analyzer 70 has not been completed (NO in step S11), the control unit 40 repeats the process of step S11.

  In the case of a YES determination in step S11, the powder discharging means 40G transmits a reverse rotation command signal to the driving member 23, rotates the screw 22 in the reverse direction, and discharges the residual sample from the cylinder 21 (remaining sample discharge). Process / Step S12).

  After the processing in step S12, the control unit 40 proceeds to the above-described steps S1 to S12 or ends a series of steps in order to start measurement of the next sample.

In the step of discharging the remaining sample (step S12), the control unit 40 sets the reverse rotation speed of the screw 22 to R ₂ (times) while the fly ash is being discharged by the powder discharging means 40G as described above. / Sec), and when the reverse rotation time of the screw 22 during that time is T ₂ (sec), it is preferable to control the driving member 23 so as to satisfy the above equation (1). In FIG. 5, the above-described setting step is omitted, but is performed in advance of the driving start step (Step S1 and Step S2).

  Although not shown in the flowchart of FIG. 5, in the case of a YES determination in step S8, the dissolving unit 51 dissolves the sample in pure water under a preset condition (sample concentration, temperature, etc.) to prepare a sample solution. . When the preparation of the sample solution is completed in the dissolving section 51, a sample solution preparation end signal is transmitted from the dissolving section 51. When the sample solution preparation end signal is transmitted, the analysis sample take-out unit 52 takes out a predetermined amount of the sample solution from the dissolving unit 51 according to desired conditions, puts a predetermined amount of the sample solution into the analyzer 70, and Drain the sample solution. Then, the analysis sample removing unit 52 transmits an analysis process start signal. When the analysis process start signal is transmitted to the analyzer 70, the analyzer 70 starts analyzing the properties of the sample according to desired conditions, and displays the result on the display device. After completing the analysis of the sample, the analyzer 70 transmits an analysis process end signal to the controller 40.

  A series of steps by the dissolving unit 51, the analysis sample removing unit 52, and the analyzer 70 may be displayed on a display device (not shown). Further, a series of steps by the dissolving section 51, the analysis sample removing section 52, and the analyzer 70 may be performed under the control of a control section different from the control section 40. It may be performed in response to a command operation or the like from the user.

<Preliminary Test> Measurement of the amount of change in the load measured by the load measuring unit (load cell) 30 after the start of driving by the powder delivery member 20

[Preliminary test 1]
In the powder supply device 1 illustrated in FIG. 1, the amount of change in the load measured by the load measuring unit 30 after the start of the driving by the powder sending unit 20 was measured. The sample was incinerated fly ash of municipal waste. Further, the rotation speed _{R 1} of the screw 22 in the powder delivery member 20 was set to 25 rpm.

  FIG. 6 shows the results. The horizontal axis in FIG. 6 is the elapsed time (unit: minute) elapsed since the start of the driving by the powder feeding unit 20, and the vertical axis is the weighed value (unit: g) of the load measuring unit 30. The horizontal axis in FIG. 7 is the elapsed time (unit: second) elapsed since the start of the driving by the powder feeding unit 20, and the vertical axis is the weighed value (unit: g) of the load measuring unit 30. From FIGS. 6 and 7, when the driving of the screw 22 is started, the measured value of the load measuring unit 30 increases, and after 2 seconds from the driving of the screw 22, the measured value of the load measuring unit 30 reaches a maximum. confirmed.

[Preliminary test 2]
In the powder supply device 1 illustrated in FIG. 1, the driving by the powder delivery unit 20 has been started. The sample and the driving conditions are the same as in the preliminary test 1. Then, two seconds after the start of the driving by the powder sending section 20, the driving by the powder sending section 20 was stopped. Then, the amount of change in the load measured by the load measuring unit 30 after the start of the driving by the powder feeding unit 20 was measured.

  FIG. 8 shows the results. The horizontal axis in FIG. 8 is the elapsed time (unit: minute) elapsed from the start of the driving by the powder feeding unit 20, and the vertical axis is the change amount of the load measuring unit 30. From FIG. 12, when the driving of the screw 22 is switched from the start state to the stop state, the measured value of the load measuring unit 30 fluctuates thereafter, and it takes about 15 minutes until the measured value of the load measuring unit 30 is stabilized. Is required.

It is presumed that the fluctuation of the measured value of the load measuring unit 30 occurs as follows.
When the driving of the driving member 23 is to be started, the belt chain 233 connecting the rotating shaft 221 of the screw 22 and the driving shaft 234 of the driving motor is tightened, and rotates in the direction of arrow A. On the other hand, the distance X between the rotation shaft 221 of the screw 22 and the drive shaft 234 of the drive motor is slightly reduced in the direction of arrow B in the drawing, and the position of the center of gravity of the powder delivery unit 20 moves as shown by arrow C. As a result, distortion occurs in the powder delivery unit 20.

  On the other hand, when the driving of the driving member 23 is stopped, the belt chain 233 connecting the rotating shaft 221 of the screw 22 and the driving shaft 234 of the driving motor becomes loose, and the belt chain 233 between the rotating shaft 221 of the screw 22 and the driving shaft 234 of the driving motor is loosened. The distance X returns in the direction opposite to the direction of the arrow B, and the center of gravity of the powder feeding unit 20 returns to the original position. Take it.

  The load measuring unit 30 is fixed in a cantilever shape. Therefore, when the driving state of the powder feeding section 20 is switched, the load measuring section 30 detects that the position of the center of gravity has moved in the longitudinal direction.

  Therefore, it is inferred that the measured value of the load measuring unit 30 fluctuates.

<Main test> Comparison of tare timing [Example]
In the analysis sample supply device 50 shown in FIG. 4, fly ash (sample) was measured according to the flowchart shown in FIG. In this example, each condition is as follows.

(1) The sample is incinerated fly ash of municipal waste.
(2) In one measurement, 15 g of fly ash was measured.
(3) In the driving start step (step S2), and the rotational speed _{R 1} of the screw 22 and 25 rpm, and the rotation direction and forward rotation (direction of the screw 22 conveys the powder from the inlet 21A to the outlet 21B).
(4) From the preliminary test, it was confirmed that the time required from when the driving of the screw 22 was started to when the amount of change in the load measured by the load measuring unit 30 became the maximum for the first time was 2 seconds. Therefore, the rotation time _{T 1} of the screw 22 in the driving start step (step S2) was set for 2 seconds.
(5) In the drive restarting step (step S6), the rotation speed of the screw 22 was set to 25 rpm, and the rotation direction was set to normal rotation.
(6) The analyzer is an alkalinity analyzer. The interval time required for the analysis was 30 minutes.
(7) Upon completion of the analysis, a residual sample discharging step (Step S12) was performed. In the remaining sample discharge step (step S12), the rotation speed _{R 2} of the screw 22 and 25 rpm, was the rotation direction reverse rotation (the direction in which the screw 22 conveys the powder from the outlet 21B to the inlet 21A). Rotation time _{T 2} of the screw 22 was set to 2 seconds.
(8) After the residual sample discharging step (Step S12), the above (1) to (7) were repeated again. The number of repetitions was 20 times.

(Comparative example)
In the analysis sample supply device 50 shown in FIG. 4, fly ash (sample) was weighed according to the flowchart shown in FIG. Comparing the example with the comparative example, the tare timing of the load measuring unit 30 is different, and other conditions are the same.

[Results and discussion]
The measurement results in the examples are shown in Table 1 below.

From the results in Table 1, the average value of the measurement results in the examples was 14.96 g, and the coefficient of variation was 4.60%. FIG. 9 shows the variation coefficients of the example and the comparative example.
Note that the standard deviation was calculated by the following equation, with the average value of the measurement results as X and the n-th measurement result as _xn . The coefficient of variation is a value obtained by dividing the standard deviation by the average value.
Standard deviation = (Σ (x _n −X) ² / n) ^1/2

  From the results of FIG. 9, it is found that in the embodiment in which the driving of the screw 22 is started and the driving is stopped, the sample is tared before the driving of the screw 22 is started. It was confirmed that the weight was well measured and that the results had little variation.

  If the powder supply device 1 is a bagging device that packs raw materials such as flour, weighing is performed without an interval between weighing operations. , Few times a day. Once the driving of the powder feeding section 20 is stopped, the driving of the powder feeding section 20 is started next 15 minutes or more after the driving of the powder feeding section 20 is stopped. Therefore, even if the measured value of the load measuring unit 30 fluctuates after the driving state of the powder sending unit 20 is switched, the driving of the powder sending unit 20 is started next only when the measured value of the load measuring unit 30 is changed. Is stable, the fluctuation of the measured value of the load measuring unit 30 can be ignored.

  However, when the object to be measured is a powder supplied to the analyzer such as incineration ash or the like, the cutting-out device is stopped for each measuring operation, and an interval corresponding to the time required for analysis is provided for each measuring operation. . The time required for the analysis for each weighing operation may be shorter than the time required for the fluctuation of the weighed value of the load measuring unit 30 to stop. Therefore, the next drive of the powder delivery unit 20 is started before the measured value of the load measuring unit 30 is stabilized. Fluctuation cannot be ignored.

  Further, incineration ash and the like are used for analyzing components and properties (eg, alkalinity) by dissolving in water, so that the measurement error of the load measuring unit 30 cannot be ignored in terms of improving the accuracy of the analysis result.

  In the case of the powder supply device 1 according to the embodiment, the object to be measured is the powder to be supplied to the analyzer, such as incineration ash, and even if the interval between the measurement operations is short, the powder is accurately measured. Can be weighed.

DESCRIPTION OF SYMBOLS 1 Powder supply apparatus 10 Powder accommodating part 20 Powder sending part 21 Cylindrical body 22 Screw 23 Drive member 231 Bearing part 232 Drive part 233 Belt chain 234 Drive shaft 30 Load measuring part (load cell)
DESCRIPTION OF SYMBOLS 31 Flexure element 32 Strain gauge 40 Control part 50 Analytical sample supply device 51 Melting part 52 Analytical sample take-out part 60 Stand 70 Analysis device

Claims (7)

A powder storage unit for storing the powder,
A powder delivery unit that delivers the powder stored in the powder storage unit to the outside,
A load measuring unit fixed in a cantilever shape and measuring a load applied from the powder sending unit,
A control unit that is electrically connected to the powder delivery unit and the load measurement unit, and controls a sending amount of the powder stored in the powder storage unit to the outside,
The powder sending section,
A powder delivery member that delivers the powder stored in the powder storage unit to the outside,
A driving member for driving the powder delivery member,
The control unit includes:
Start command means for instructing the drive member to start driving the powder delivery member,
After instructing the start of the driving of the powder feeding member, when a predetermined time equal to or longer than the time required until the amount of change in the load measured by the load measuring unit reaches a local maximum for the first time, the driving member is On the other hand, stop command means for commanding the stop of the driving of the powder sending member,
Start of drive by the start command means, and when the stop of the drive by the stop command means is performed, to the load measuring unit, tare instruction means for instructing the tare of the load measuring unit,
A powder supply device, comprising: a start re-instruction unit for instructing the drive member to start driving the powder delivery member again in response to the tare cancellation command.   2. The powder supply device according to claim 1, further comprising: a storage unit in which a predetermined time equal to or longer than a time required until a change amount of the load measured by the load measurement unit reaches a maximum for the first time is stored in advance. A powder supply device according to claim 1 or 2,
A solvent is contained therein, and a dissolving unit that dissolves the powder sent from the powder sending unit,
Further comprising an analysis sample take-out unit for taking out a solution of the powder by the solvent as an analysis sample,
The control unit includes:
From the measurement result of the load measuring unit, a weight measuring unit that measures the weight that the powder is sent from the powder sending unit to the melting unit,
After instructing the start of the driving of the powder delivery member by the start re-instruction unit again, when the weight measured by the weight measurement unit reaches a predetermined value, the powder is transmitted to the driving member. An analysis sample supply device having stop re-instruction means for instructing again to stop driving of the sending member. The powder delivery member includes a screw that rotates about a predetermined rotation axis,
The control unit instructs the driving member to rotate the screw in a direction opposite to a direction in which the powder stored in the powder storage unit is sent to the outside. Further comprising a powder discharging means for discharging the powder remaining in the melting part to a different place,
The rotation speed of the screw from a command to start the rotation of the screw by the start command means to a command to stop the rotation of the screw by the stop command means is R ₁ (times / second), The rotation time is T ₁ (second), the reverse rotation speed of the screw during discharge of the powder by the powder discharge means is R ₂ (times / second), and the reverse rotation of the screw during the discharge is R ₂ (times / second). when the rotation time T _{2 (sec),} satisfy formula (1), analytical sample supply apparatus according to claim 3.
0.01 ≦ T ₁ ≦ R ₂ × T ₂ ÷ R ₁ (1) When the reverse rotation time of the screw required for discharging all the powder remaining inside the powder delivery member by the powder discharging means is T ₂₀ (seconds), the following expression (2) is satisfied. The analysis sample supply device according to claim 4, which performs the analysis.
T ₂ ≦ T ₂₀ (2) A powder supply method for supplying a predetermined amount of powder from a powder supply device,
The powder supply device,
A powder storage unit for storing the powder,
A powder delivery unit that delivers the powder stored in the powder storage unit to the outside,
Fixed to a cantilever beam, comprising a load measuring unit for measuring the load applied from the powder delivery unit,
The method comprises:
A driving start step of starting driving the powder delivery member,
After the start of the driving of the powder delivery member, when a predetermined time equal to or longer than the time required for the amount of change in the load measured by the load measurement unit to reach a maximum for the first time has elapsed, the drive of the powder delivery member is performed. A drive stop process for stopping,
Tare step of performing a tare of the load measuring unit,
And a drive restarting step of restarting the driving of the powder delivery member after the taring.   Prior to the driving start step, the driving of the powder feeding member is started, a time-dependent change in the amount of change in the load measured by the load measuring unit is measured, and the predetermined time is set in advance from the measurement result. The powder supply method according to claim 6, further comprising:

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