JP2010197004A - Device and method of dewatering green veneer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dewatering device capable of removing much moisture content from a green veneer in a short time. <P>SOLUTION: This dewatering device includes: a pair of surface plates disposed to face each other; a driving means for applying a pressure to a veneer laminated body held between the pair of surface plates by making the pair of surface plates approach to each other, and driving at least one of the pair of surface plates to squeeze up moisture content from each green veneer; a pressure detecting means for detecting the pressure added to the veneer laminated body; and a control means for monitoring the magnitude of the pressure detected by the pressure detecting means, and controlling the driving means to unload the applied pressure by driving at least one of the surface plates after keeping a prescribed pressure for a first time, when the pressure between the surface plates reaches the prescribed pressure determined on the basis of a thickness of the green veneer constituting the veneer laminated body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dehydrating apparatus and a dehydrating method for pressing a raw veneer to remove moisture inside the raw veneer.

  As a structural material used in a house or the like, a plywood formed by bonding a plurality of wood single plates into a plate shape is widely used. A veneer forming this plywood is manufactured by the following steps.

  First, a raw veneer is cut out by a rotary race from the raw wood that has been cut to a length of about 2 m and from which the skin has been removed. The rotary race applies a blade along the outer circumferential direction of the raw wood that rotates around its axis, cuts out a thin plate with a substantially constant thickness, and cuts this thin plate at regular lengths along the length of the raw wood, This is a device that generates a plurality of rectangular raw veneers having substantially constant dimensions from a single log.

  Raw wood and raw veneer cut from raw wood contain a lot of moisture. Such a raw veneer containing a lot of moisture cannot be bonded as it is to make a plywood, and it is necessary to dry the raw veneer sufficiently in advance. Therefore, the raw veneer is accommodated in the chamber, and the raw veneer is dried by blowing hot air from the dryer to the accommodated raw veneer. However, since the raw veneer contains a large amount of moisture, it takes time to dry only with the dryer, and the energy consumption of the dryer becomes very large.

  For this reason, a dehydrating apparatus that removes moisture from a green veneer before drying with a dryer, such as that described in Patent Document 1, has been proposed. The dehydrating apparatus described in Patent Document 1 passes a single plate between a pair of rollers one by one, presses the single plate with a roller, and squeezes out moisture from the single plate.

JP-A-60-99983

  A conventional dewatering apparatus such as that described in Patent Document 1 is such that a single plate is pressed for a short time at a minute contact portion between the roller and the single plate. However, only by pressing the green veneer between rollers for a short time, the water content of the green veneer could not be removed sufficiently. On the other hand, it is conceivable to slow down the feed speed of the raw veneer and increase the time during which a specific part of the raw veneer is pressed between the rollers. In this case, the dewatering time per raw veneer is longer. Problem arises.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a raw veneer dewatering apparatus and a dehydrating method that can remove more water from the green veneer in a short time.

  In order to achieve the above object, a raw veneer dewatering apparatus according to the present invention is sandwiched between a pair of surface plates by bringing a pair of surface plates close to each other and a pair of surface plates placed close to each other. Driving means for driving at least one of the pair of surface plates so that moisture is removed from each single veneer by applying pressure to the single veneer, and pressure detecting means for detecting pressure applied to the single veneer And the magnitude of the pressure detected by the pressure detecting means, and when the pressure between the platens reaches a predetermined pressure determined by the thickness of the raw veneer constituting the single plate laminate, the predetermined time is predetermined. After maintaining the pressure, there is provided control means for controlling the driving means so as to drive at least one surface plate to unload the pressure.

  The raw veneer dewatering method of the present invention includes an arrangement step of arranging a single plate laminate formed by laminating raw veneers between a pair of surface plates arranged to face each other, and a pair of In the first pressurizing step, a first pressurizing step in which water is removed from each green veneer by applying pressure to a single plate laminate sandwiched between a pair of platens with the platens close to each other. A first pressure maintaining step for maintaining a pressure state that takes a first time when the pressure between the platens reaches a predetermined pressure determined by the thickness of the green veneer constituting the plate laminate, and the first pressure maintaining And a first unloading step of unloading the pressure by separating the pair of surface plates after the step.

  As described above, the dehydrating apparatus of the present invention presses the entire raw veneer between a pair of surface plates at the same time. The press time per unit area of the raw veneer can be increased without extending the processing time. Thereby, more water | moisture content can be removed from a raw veneer. When performing dehydration by such a method, the pressure applied to the raw veneer by the surface plate may cause different pressing unevenness between the one end side and the other end side of the raw veneer. In the method, since a single plate laminate in which a plurality of green veneers are stacked is pressed at a time, such pressing unevenness is reduced, and the green veneers are pressed substantially uniformly. Furthermore, since a plurality of raw veneers can be pressed at a time, the moisture of the raw veneers can be efficiently removed.

FIG. 1 is a front view of a dehydrating apparatus according to an embodiment of the present invention. FIG. 2 is a side view of the dehydrating apparatus according to the embodiment of the present invention. FIG. 3 is a block diagram showing elements for driving each hydraulic cylinder of the dehydrating apparatus according to the embodiment of the present invention. FIG. 4 shows an inclination sensor according to an embodiment of the present invention. FIG. 5 is a flowchart showing the procedure of the dehydration process by the dehydrator according to the embodiment of the present invention. FIG. 6 is a graph showing the variation of the load applied to the laminated veneer veneer at each step of the flowchart of FIG. FIG. 7 is a flowchart of a movable surface plate inclination monitoring routine by the dehydrator according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show a front view and a side view of the dehydrating apparatus of the present embodiment, respectively.

  As shown in FIGS. 1 and 2, the dehydrating apparatus 1 of the present embodiment includes an apparatus frame 10, a fixed surface plate 22, a movable surface plate 24, and a drive mechanism 30. In the following description, the horizontal direction in FIG. 1 (direction perpendicular to the paper surface in FIG. 2) is the width direction, the direction perpendicular to the paper surface in FIG. 1 (left and right direction in FIG. 2) is the depth direction, and FIGS. The vertical direction is defined as the height direction.

  The frame 10 has a pair of legs 11 fixed on a base B that is a substantially horizontal plane, a bottom plate 12 fixed on the legs 11, fixed on both widthwise ends of the bottom plate 12, and extends in the height direction. A pair of side plates 13 and a top plate 14 fixed on the side plates 13 so as to communicate with the upper ends of the side plates 13 are provided. In addition, depth direction frame plates 15 a are formed on both sides in the depth direction of the U-shaped portion composed of the top plate 14 and the side plate 13. Further, a main cylinder fixing frame 15b is provided so as to communicate the bottoms of the pair of depth direction frame plates 15a. Further, the tank fixing frame 16 is fixed to the upper outer surface of the pair of depth direction frame plates.

  The drive mechanism 30 includes four main hydraulic cylinders 31 arranged side by side in the width direction, and first and second sub hydraulic cylinders 32a and 32b arranged at both ends in the width direction. The sleeve portion of the main hydraulic cylinder 31 is fixed to the main cylinder fixing frame 15b. The cylinder portions of the first and second sub hydraulic cylinders 32 a and 32 b are fixed to the top plate 14 via fixing members (not shown) formed on the top plate 14 of the frame 10. Each sleeve portion of the main hydraulic cylinder 31 and the first and second sub hydraulic cylinders 32a and 32b incorporates a piston (not shown), and a piston rod extending downward is fixed to each piston.

  The fixed surface plate 22 is fixed on the bottom plate 12 of the frame 10. A movable surface plate 24 is fixed to the front end (lower end) of the piston rod of the main hydraulic cylinder 31 and the first and second sub hydraulic cylinders 32a and 32b. That is, the movable surface plate 24 is suspended from the frame 10 via the main hydraulic cylinder 31 and the first and second auxiliary hydraulic cylinders 32a and 32b. 1 and 2, the fixed surface plate 22 is disposed immediately below the movable surface plate 24, and the lower surface 24a of the movable surface plate 24 and the upper surface 22a of the fixed surface plate 22 face each other. is doing.

  An oil tank 41 that stores hydraulic oil supplied to the main hydraulic cylinder 31 and the first and second auxiliary hydraulic cylinders 32a and 32b is fixed to the tank fixing frame 16. The working oil in the oil tank 41 is pumped out by a pump 42 (not shown in FIGS. 1 and 2) and supplied to each hydraulic cylinder to move the piston rod of each hydraulic cylinder up and down.

  As described above, since the movable surface plate 24 and the fixed surface plate 22 face each other, a laminated veneer single plate formed by laminating many raw veneers is disposed between the movable surface plate 24 and the fixed surface plate 22. Then, the laminated veneer single plate can be pressed between the fixed surface plate 22 and the movable surface plate 24 by driving each hydraulic cylinder to lower the movable surface plate 24. The laminated veneer veneer conduits extend along the long or short face of each veneer, and each conduit breaks at the edge of the veneer. Therefore, when the laminated veneer veneer is pressed, moisture contained in the conduit of each veneer is squeezed out and leaked and removed from the edge of the veneer. As shown in FIG. 1, the bottom plate 12 of the frame 10 is formed in a container shape whose substantially central portion is recessed downward with respect to the edge portion, and the water squeezed from the single plate is temporarily stored. It is a bat part that is stored. As shown in FIGS. 1 and 2, the fixed surface plate 22 and the movable surface plate 24 of the present embodiment are shorter in the depth direction than in the width direction. For this reason, the laminated veneer veneer is carried onto the fixed surface plate 22 with the surface long sides approximately directed in the width direction of the dehydrator 1.

  Next, control of the dehydrator 1 will be described. FIG. 3 is a block diagram illustrating a configuration for driving the hydraulic cylinders 31, 32 a, and 32 b of the dehydrator 1. As shown in FIG. 3, the dehydrating apparatus 1 further includes a controller 51, a load sensor 52, a tilt sensor 53, a main servo valve 43, a first sub servo valve 44a, and a second sub servo valve 44b. In FIG. 3, solid arrows indicate control signals and sensor outputs, and broken arrows indicate the movement of hydraulic oil.

  The pump 42 pumps the working oil from the oil tank 41 and sends it to the main servo valve 43 and the first and second sub servo valves 44a and 44b. The main servo valve 43, the first and second sub servo valves 44a, 44b are connected to the main hydraulic cylinder 31, the first and second sub hydraulic cylinders 32a, 32b, respectively. Each servo valve has a corresponding pressure cylinder head-side pressure chamber (in the inner space of the sleeve divided into two by the piston, the space on the side where the piston rod is not arranged; the upper side in FIGS. 1 and 2) and the rod-side pressure. The chamber (the space on the side where the piston rod is arranged in the internal space of the sleeve, which is lower in FIGS. 1 and 2) is switched and the pressure of the hydraulic oil sent to the pressure chamber is controlled. It has the function to do. The controller 51 controls whether the working oil is sent to the head side pressure chamber or the rod side pressure chamber, and the pressure of the working oil sent to the pressure chamber. The hydraulic oil in the pressure chamber on the side where hydraulic oil is not sent is pushed out of the hydraulic cylinder as the piston moves, and the pushed hydraulic oil is returned to the oil tank 41. The pump 42 pumps the working oil from the oil tank 41 at a constant flow rate, but the remaining working oil that is not sent to the hydraulic cylinder via each servo valve is returned to the oil tank 41 as it is. In other words, the pump 42 circulates the working oil from the oil tank 41 to the path returning to the oil tank 41 again via each servo valve, and a part of the circulating working oil passes to each hydraulic cylinder via the servo valve. It is supposed to be sent.

  As described above, in the present embodiment, the controller 51 controls the servo valves 43, 44a, and 44b to move the piston rods of the hydraulic cylinders 31, 32a, and 32b up and down and to operate the hydraulic cylinders. The oil pressure (ie, the load that the hydraulic cylinder applies to the laminated veneer veneer) can be controlled.

  Here, the main hydraulic cylinder 31 is driven after the upper surface of the laminated veneer single plate comes into contact with the lower surface 24a of the movable surface plate 24, and is used to press the laminated veneer single plate. For this reason, as shown in FIG. 1, four main hydraulic cylinders 31 having a larger diameter than the sub hydraulic cylinders 32a and 32b are used, and a large load can be applied to the laminated veneer single plate. ing. The auxiliary hydraulic cylinders 32 a and 32 b are used for the vertical movement of the movable surface plate 24. That is, the auxiliary hydraulic cylinders 32a and 32b are used to lower the movable surface plate 24 until the upper surface of the laminated veneer single plate comes into contact with the lower surface 24a, and to raise the movable surface plate 24 after the press is finished. For this reason, the auxiliary hydraulic cylinders 32a and 32b have small diameters that can move the movable surface plate 24 up and down.

  The load sensor 52 is, for example, a load cell provided in the movable surface plate 24, and detects a press load when the main hydraulic cylinder 31 presses the laminated veneer single plate. The controller 51 controls the main servo valve based on the detection result of the load sensor 52 so that the laminated veneer single plate is pressed with a desired load.

  The tilt sensor 53 is a sensor for detecting the tilt of the movable surface plate 24 in the width direction (that is, the surface long side direction of the single plate) with respect to the horizontal plane (that is, the upper surface 22a of the fixed surface plate 22). The inclination of the movable surface plate 24 detected by the inclination sensor 53 is sent to the controller 51. The controller 51 controls each servo valve 43, 44a, 44b based on the detection result of the tilt sensor 53. For example, when the movable surface plate 24 is raised or lowered, the sub hydraulic cylinders 32a and 32b are controlled so that the inclination of the movable surface plate 24 with respect to the horizontal plane is within a predetermined range. Alternatively, an alarm is issued and the main hydraulic cylinder 31 is forcibly stopped when the inclination of the movable surface plate 24 with respect to the horizontal plane exceeds a predetermined threshold due to variations in the density of each single plate during pressing.

  The tilt sensor 53 will be described below. As shown in FIG. 4, the tilt sensor 53 is wound around a pair of bearings 53a fixed to the upper surface of the movable surface plate 24, a spool 53b pivotally supported by the pair of bearings, and the spool 53b. In addition, one end has a lower surface of the top plate 14 of the frame 10 and the other end has a wire 53c fixed to the spool 53b. The spool 53b is provided with a torsion spring (not shown), and applies a certain tension to the wire 53c. Further, the spool 53b is provided with a rotary encoder 53d, and the number of rotations of the spool can be detected. A pair of a bearing 53a, a spool 53b, a wire 53c, and a rotary encoder 53d is provided on each side in the width direction of the space between the top plate 14 and the movable surface plate 24, and a circuit (not shown) of the tilt sensor 53 is provided. The unit can detect the inclination of the movable surface plate 24 based on the difference between the rotational speeds detected by the pair of rotary encoders 53d.

  A circuit unit (not shown) of the tilt sensor 53 calculates the interval between the top plate 14 and the movable surface plate 24 based on the average value of the rotational speeds detected by the pair of rotary encoders 53d, and transmits this to the controller 51. ing. The controller 51 calculates the interval between the movable surface plate 24 and the fixed plate 22 based on this interval.

  Next, a procedure for dewatering the laminated veneer veneer by the dewatering device 1 of this embodiment will be described. FIG. 5 is a flowchart showing a procedure of dehydration processing by the dehydrating apparatus 1 of the present embodiment. Moreover, FIG. 6 is a graph which shows the fluctuation | variation of the load added to a laminated veneer single board in each step of the flowchart of FIG. Before the process of FIG. 5 is started, the movable surface plate 24 is raised to a sufficiently high position so that the laminated veneer single plate can be carried into the fixed surface plate 22.

  When the processing shown in FIG. 5 is started, a set of laminated veneer single plates is taken out from the stocker outside the dehydrator 1 by a forklift or the like and placed on the fixed surface plate 22 (step S1). The stocker accommodates at least one set of laminated veneer single plates. The laminated veneer veneer accommodated in the stocker is a stack of many raw veneers with their short sides and long sides aligned, and the height is the average value of the short side dimensions of the raw veneer It is about half to about twice the size of.

  Next, step S2 is executed. In step S2, the controller 51 controls the first and second sub servo valves 44a and 44b to lower the movable surface plate 24. At this time, the controller 51 controls the main servo valve 43 so that the movable surface plate 24 can be freely lowered (control so that the working oil flows into the pressure chamber on the head side of the main hydraulic cylinder 31 at atmospheric pressure. To do). The controller 51 monitors the magnitude of the load detected by the load sensor 52. When this load exceeds a predetermined value, the controller 51 determines that the lower surface 24a of the movable surface plate 24 is in contact with the laminated veneer single plate. Then, the operation of the auxiliary hydraulic cylinders 32a and 32b is stopped.

  Next, the controller 51 drives the main servo valve 43 to lower the movable surface plate 24 while pressing the laminated veneer single plate. At this time, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be freely lowered (so that the working oil flows into the pressure chamber on the head side of the sub hydraulic cylinder at atmospheric pressure). Control). The controller 51 calculates the pressure (L / A) applied to the laminated veneer single plate based on the load L detected by the load sensor 52 and the bottom area A of the laminated veneer single plate. The controller 51 lowers the movable surface plate 24 until this pressure reaches the press pressure P. The pressing pressure P is determined by the thickness of the raw veneer constituting the laminated veneer veneer. Specifically, the press pressure P is set smaller as the thickness of the raw veneer increases. For example, when the thickness of the raw veneer is 2.7 mm, the press pressure P is set to a value between 1.5 and 1.7 MPa, and when the thickness is 3.4 mm, the press pressure P is 1 In the case where the thickness is 3.5 mm or more, the press pressure P is set to a value between 1.1 and 1.3 MPa.

Next, step S3 is executed. In step S3, the controller 51 based on the detection result of the load sensor 52, during a certain time T ₁ of the between 150 230 seconds, laminated veneer with a load L maintains the state of being pressed.

  Next, step S4 is executed. In step S4, the controller 51 drives the main servo valve 43 to raise the movable surface plate 24 while reducing the load applied to the laminated veneer single plate. At this time, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be freely raised (so that the working oil flows into the pressure chamber on the rod side of the sub hydraulic cylinder at atmospheric pressure). Control). The controller 51 monitors the magnitude of the pressure applied to the laminated veneer single plate based on the magnitude of the load detected by the load sensor 52, and raises the movable surface plate 24 until this pressure becomes substantially zero. As the movable surface plate 24 is raised, each single plate constituting the laminated veneer single plate is deformed so that the dimension in the thickness direction is restored, and the height of the laminated veneer single plate increases. When each veneer cannot be restored any more, the pressure applied to the laminated veneer veneer becomes substantially 0, and at this time, the upper surface of the laminated veneer veneer and the lower surface of the movable surface plate 24 are in light contact with each other. .

  Next, step S5 is executed. In step S5, the movable surface plate 24 is stopped for a short time (about several seconds).

  Next, step S6 is executed. In step S6, the controller 51 drives the main servo valve 43 to lower the movable surface plate 24 while pressing the laminated veneer single plate. The controller 51 monitors the pressure applied to the laminated veneer single plate based on the load detected by the load sensor 52, and lowers the movable surface plate 24 until this pressure reaches the press pressure P. In this step, since the movable surface plate 24 is driven by the main hydraulic cylinder 31, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be freely lowered.

Next, step S7 is executed. In step S7, the controller 51 based on the detection result of the load sensor 52 during the predetermined time T _2, the laminated veneer at a pressure P to maintain the state of being pressed. Incidentally, pressing time T ₂ of the this time has a length of between 80% 70 of the press time T ₁ during the initial press (step S _3).

  Next, step S8 is executed. In step S8, the controller 51 drives the main servo valve 43 to raise the movable surface plate 24 while reducing the load applied to the laminated veneer single plate. At this time, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be freely raised (so that the working oil flows into the pressure chamber on the rod side of the sub hydraulic cylinder at atmospheric pressure). Control). The controller 51 monitors the pressure applied to the laminated veneer single plate based on the magnitude of the load detected by the load sensor 52, and raises the movable surface plate 24 until this pressure becomes substantially zero. As the movable surface plate 24 is raised, each single plate constituting the laminated veneer single plate is deformed so that the dimension in the thickness direction is restored, and the height of the laminated veneer single plate increases. When each veneer cannot be restored any more, the pressure applied to the laminated veneer veneer becomes substantially 0, and at this time, the upper surface of the laminated veneer veneer and the lower surface of the movable surface plate 24 are in light contact with each other. .

  Next, step S9 is executed. In step S9, the movable surface plate 24 is stopped for a short time (about several seconds).

  Next, step S10 is executed. In step S10, the controller 51 drives the main servo valve 43 to lower the movable surface plate 24 while pressing the laminated veneer single plate. The controller 51 monitors the pressure applied to the laminated veneer single plate based on the load detected by the load sensor 52, and lowers the movable surface plate 24 until this pressure reaches the press pressure P. In this step, since the movable surface plate 24 is driven by the main hydraulic cylinder 31, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be cured freely.

Next, step S11 is executed. In step S11, the controller 51 based on the detection result of the load sensor 52 during the predetermined time T _2, a press pressure P is stacked veneer to maintain the state of being pressed.

  Next, step S12 is executed. In step S12, the controller 51 drives the main servo valve 43 to raise the movable surface plate 24 while reducing the load applied to the laminated veneer single plate. At this time, the controller 51 controls the sub servo valves 44a and 44b so that the movable surface plate 24 can be freely raised (so that the working oil flows into the pressure chamber on the rod side of the sub hydraulic cylinder at atmospheric pressure). Control). The controller 51 monitors the pressure applied to the laminated veneer single plate based on the magnitude of the load detected by the load sensor 52, and raises the movable surface plate 24 until this pressure becomes substantially zero. As the movable surface plate 24 is raised, each single plate constituting the laminated veneer single plate is deformed so that the dimension in the thickness direction is restored, and the height of the laminated veneer single plate increases. When each veneer cannot be restored any more, the pressure applied to the laminated veneer veneer becomes substantially 0, and at this time, the upper surface of the laminated veneer veneer and the lower surface of the movable surface plate 24 are in light contact with each other. .

  Next, the controller 51 controls the first and second sub servo valves 44a and 44b to raise the movable surface plate 24. At this time, the controller 51 controls the main servo valve 43 so that the movable surface plate 24 can freely move up (control so that the working oil flows into the pressure chamber on the rod side of the main hydraulic cylinder 31 at atmospheric pressure. To do). Then, the distance between the fixed surface plate 22 and the movable surface plate 24 calculated based on the distance between the top plate 14 and the movable surface plate 24 detected by the tilt sensor 53 is sufficiently large (at the interval before the start of step S2). When the controller 51 detects that it has returned), the first and second sub servo valves 44a and 44b are controlled to stop the movable surface plate 24.

  Next, step S13 is executed. In step S13, the laminated veneer veneer having been dehydrated is taken out of the dehydrator by a belt conveyor or the like, and conveyed to a dryer chamber for further removing moisture from each veneer veneer with hot air.

When the laminated veneer veneer is pressed, each veneer forming the laminated veneer veneer is compressed in the thickness direction, and moisture contained in the veneer is pushed out from the edge of the veneer and removed. However, if a certain amount of time elapses while the press is performed, the thickness of the single plate does not decrease, and moisture cannot be removed from the single plate even if the press is further performed. For this reason, in this embodiment, the dehydrating press is performed in a plurality of times. When unloading is performed after pressing once, the thickness direction dimension of the veneer increases due to the elasticity of each veneer forming the laminated veneer veneer. Then, after a few seconds after unloading (steps S5 and S9), pressing is performed again, whereby the veneer is pressed again and the moisture therein is pushed out. Thus, in the configuration in which the dewatering press is performed a plurality of times as in the present embodiment, moisture can be efficiently removed as compared with the case where the long-time dewatering press is performed only once. In particular, the moisture content of the laminated veneer veneer can be removed most effectively by the configuration in which the dehydration press is performed three times. Also, before performing the first-time press, for veneer contains much moisture, it performs during a relatively long time T ₁ press (step S3) it is necessary, at the time of second and subsequent pressing, Since a certain amount of moisture has been removed from the veneer by the first press, the press time T2 for the _second and subsequent presses is set to be shorter than the press time T1 for the _first press. The water can be removed well. In the present embodiment, although the second time and third-time pressing time and the same time, for the second and subsequent pressing, T ₁ each time to shorten the pressing time each time performing the press, or perform press It is good also as a structure which changes press time for every press, such as extending press time in the range which does not exceed this.

  Next, when the laminated veneer single plate is being pressed by the main hydraulic cylinder 31, the inclination of the movable surface plate 24 with respect to the horizontal plane is monitored, and an alarm is issued to force the main hydraulic cylinder 31 when this inclination becomes large. The control for stopping will be described. FIG. 7 is a flowchart of the movable surface plate inclination monitoring routine of this embodiment. Each step shown in this flowchart is executed by the controller 31 when the main hydraulic cylinder 31 starts to be driven (steps S3, S7 and S11 in FIG. 5).

  When this routine is executed, step S21 is executed. In step S <b> 21, the controller 51 acquires the magnitude of the inclination of the movable surface plate 24 with respect to the horizontal plane from the inclination sensor 53.

  Next, step S22 is executed. In step S22, the controller 51 determines whether or not the inclination of the movable surface plate 24 acquired in step S21 is equal to or greater than a predetermined threshold (for example, 1 °). If the inclination is less than the threshold (S22: NO), the process proceeds to step S25.

  In step S25, the controller 25 determines whether or not the main hydraulic cylinder 31 is currently pressing. If the main hydraulic cylinder 31 is pressing (S25: YES), the process returns to step S21. On the other hand, if the main hydraulic cylinder 31 is not pressing (S25: NO), the unloading is being performed on the laminated veneer veneer, that is, step S3, S7 or S11 in FIG. 5 has been completed. Because there is, this routine is terminated.

  On the other hand, when it is confirmed in step S22 that the inclination of the movable surface plate 24 is equal to or greater than a predetermined threshold (S22: YES), the process proceeds to step S23.

  In step S23, the controller 51 controls the main servo valve to reduce the hydraulic pressure applied to the main hydraulic cylinder 31, and interrupts the pressing to the laminated veneer single plate. Next, step S24 is executed and an alarm (lamp or siren) is issued.

  As described above, the controller 51 determines that the operation is abnormal when the movable surface plate 24 is tilted above a predetermined threshold, interrupts the press, issues an alarm, and indicates that the above has occurred. To the operator.

  In the present embodiment, the four main hydraulic cylinders 31 are connected to a single main servo valve, and the main hydraulic cylinders have the same hydraulic pressure. Further, while the main hydraulic cylinder 31 is pressing the laminated veneer single plate, the pressing is stopped when the inclination of the movable surface plate 24 detected by the inclination sensor 53 exceeds a predetermined threshold value. . However, the present invention is not limited to this configuration. That is, each of the four main hydraulic cylinders 31 is connected to a different servo valve, and the controller 2 allows the inclination of the movable surface plate 24 to fall within a predetermined threshold based on the detection result of the inclination sensor 53. The main hydraulic cylinder 31 may be configured to adjust the hydraulic pressure.

DESCRIPTION OF SYMBOLS 1 Dehydrator 10 Apparatus frame 12 Bottom plate 22 Fixed surface plate 24 Movable surface plate 30 Drive mechanism 31 Main hydraulic cylinder 32a First sub hydraulic cylinder 32b Second sub hydraulic cylinder 41 Oil tank 42 Pump 43 Main servo valve 44a First sub servo valve 44b Second sub servo valve 51 Controller 52 Load sensor 53 Tilt sensor

Claims (21)

A pair of surface plates arranged to face each other;
At least one of the pair of surface plates is placed so that the pair of surface plates are brought close to each other and pressure is applied to the single plate laminate sandwiched between the pair of surface plates so that moisture is squeezed out from each raw single plate. Driving means for driving;
Pressure detecting means for detecting pressure applied to the single plate laminate;
The magnitude of the pressure detected by the pressure detection means is monitored, and when the pressure between the surface plates reaches a predetermined pressure determined by the thickness of the raw veneer constituting the veneer laminate, only for the first time Control means for controlling the driving means so as to unload the pressure by driving the at least one surface plate after maintaining the predetermined pressure;
A raw veneer dewatering apparatus having   The driving means includes first cylinder means for bringing the at least one surface plate close to the other surface plate, and second cylinder means for applying pressure to the single plate laminate sandwiched between the surface plates. The dehydrator according to claim 1. The pair of surface plates includes a fixed surface plate and a movable surface plate that is driven to approach / separate the fixed surface plate,
An inclination sensor for detecting an inclination of the movable surface plate with respect to a horizontal plane;
The control means applies pressure to the single plate laminate when the inclination of the movable surface plate detected by the tilt sensor exceeds a predetermined threshold while the drive means applies pressure to the single plate laminate. The dehydrating apparatus according to claim 1 or 2, wherein the driving means is controlled so that the applied pressure is unloaded.   The tilt sensor measures the displacement of the movable surface plate at both ends of the movable surface plate, and detects the inclination of the movable surface plate based on a difference in displacement between both ends of the movable surface plate. Item 4. The dehydrator according to Item 3.   The tilt sensor includes a pair of wires passed between both ends of the movable surface plate and the apparatus frame, a pair of spools that winds the pair of wires and applies tension to the wires, and the pair of spools, respectively. The dehydrator according to claim 4, further comprising: a rotary encoder that detects the number of rotations of the movable platen, and measuring displacements at both ends of the movable surface plate based on a detection result of the rotary encoder. The said single-plate laminated body laminates | stacks a raw veneer so that the dimension of a height direction may become substantially twice from the half of the surface short side of the said raw veneer. The dehydration apparatus according to any one of the above.   The control means applies the predetermined pressure between 1.1 and 1.7 MPa to the single-plate laminate and maintains the predetermined pressure for the first time between 150 and 230 seconds. The dehydrating apparatus according to any one of claims 1 to 6, wherein the means is controlled.   The dehydrating apparatus according to any one of claims 1 to 7, wherein the predetermined pressure is set to decrease as the thickness of the green veneer increases.   After the state in which the predetermined pressure is applied to the veneer laminate is maintained for a first time, the control means unloads the pressure applied to the veneer laminate, and then re-applies to the veneer laminate. The dehydrating apparatus according to any one of claims 1 to 8, wherein the driving unit is controlled so as to maintain a state in which the predetermined pressure is applied for a second time.   The dehydrating apparatus according to claim 9, wherein the second time is shorter than the first time.   The dehydrator according to claim 10, wherein the second time is between 70 and 80% of the first time.   The dehydrating apparatus according to any one of claims 9 to 11, wherein a pressure state in which a predetermined pressure is applied to the single-plate laminate for the second time is performed a plurality of times.   Among the pair of surface plates, a bat for receiving moisture released from the side surface of each single plate when the single plate laminate is pressed between the surface plates is provided below the lower one. The dehydration apparatus according to claim 1, wherein the dehydration apparatus is provided. An arrangement step of arranging a single plate laminate formed by laminating raw single plates between a pair of surface plates arranged to face each other;
A first pressurizing step of removing moisture from each green veneer by applying pressure to the single plate laminate sandwiched between the pair of platens close to the pair of platens;
When the pressure between the platens reaches a predetermined pressure determined by the thickness of the raw veneer constituting the veneer laminate in the first pressurizing step, a pressure state that takes a first time is maintained. 1 pressure maintenance step;
A raw veneer dewatering method comprising: a first unloading step of unloading the pressure by separating the pair of surface plates after the first pressure maintaining step.   The dewatering method according to claim 14, wherein the single plate laminate is laminated so that a dimension in a height direction is about half to about twice a short side of the green veneer. The predetermined pressure is between 1.1 and 1.7 MPa;
The dehydration method according to claim 14 or 15, wherein the first time is between 150 and 230 seconds.   The dehydration method according to any one of claims 14 to 16, wherein the predetermined pressure is set so as to decrease as the thickness of the green veneer increases. After the first unloading step, the pair of surface plates are brought close to each other and pressure is applied to the single plate laminate sandwiched between the pair of surface plates to remove moisture from each green veneer. A pressure step;
A second pressure maintaining step of maintaining a pressure state that takes a second time when the pressure between the surface plates reaches the predetermined pressure in the second pressurizing step;
The second unloading step of unloading the pressure by separating the pair of surface plates after the second pressure maintaining step is further provided. Dehydration method.   The dehydration method according to claim 18, wherein the second time is shorter than the first time.   The dehydration method according to claim 19, wherein the second time is between 70 and 80% of the first time.   The dehydration according to any one of claims 18 to 20, wherein the second pressurizing step, the second pressure maintaining step, and the second unloading step are performed a plurality of times. apparatus.

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