JP4859735B2 - Operation method of squeeze type dehydrator - Google Patents

Description

  This invention pressurizes the laundry discharged together with the washing water onto the conveying belt or tray having water permeability with the elastic pressing surface of the pressing body descending from above, and removes moisture contained in the laundry. The present invention relates to a method for operating a discharge-type laundry dehydrator to be discharged.

  The laundry-type squeezing dehydrator is provided with an elastic pressing surface (the lower surface of an elastic membrane forming a pressurized fluid chamber on the lower surface or upper portion of a solid elastic body such as a sponge) for moisture contained in the laundry. It is a device that pushes and squeezes with the body and dehydrates it, and is mainly used in a washing line for washing a large amount of commercial towels and sheets in combination with a continuous washing machine. This type of squeezing type dehydrator has a higher processing speed than a centrifugal dehydrator and the like, and is particularly suitable for dehydrating laundry discharged from the washing machine as a lump for each washing rod. Since an object becomes a lump of a predetermined shape, it is convenient for conveyance to a laundry dryer by a conveyance conveyor or the like.

  For example, as shown in FIG. 7, this type of squeezing type dehydrator is disposed at the upstream end portion in the transport direction of the transport conveyor 4 having a transport surface having water permeability. The laundry discharge chute 41 from the washing machine is directed to the upstream end portion of the conveyor, and the peripheral wall 17 provided with a number of drain holes is arranged upstream of the conveyor so that the laundry dropped from the chute 41 does not spread around. The end portion is surrounded. The upstream end portion of the transfer conveyor is placed on a receiving plate 5 provided with a drain hole, and the transfer surface of the transfer conveyor 4 on the receiving plate and the peripheral wall 17 form a basket 2 having water permeability. is doing. When the laundry is received from the washing machine and when the laundry is dehydrated, the lower edge of the peripheral wall 17 is pressed against the transport surface of the transport conveyor 4, and when the dehydrated laundry is carried out of the basket, the peripheral wall 17 Moves upward to form an opening for conveying the laundry between the conveyor belt and the peripheral wall 17.

  Above the basket 2, a hydraulic cylinder 8 with the rod 9 facing downward is disposed, and the pressing body 1 is fixed to the lower end of the rod 9. By the downward movement of the rod 9, the pressing body 1 descends in the basket 2 and squeezes the laundry with the receiving plate 5 to dehydrate the laundry. The lower surface of the pressing body 1 shown in the figure is formed of an elastic film 11, and a fluid chamber 12 is formed between the base disk 10 above the elastic film. The fluid chamber 12 is normally filled with water, and the elastic membrane 11 is deformed according to the shape of the upper surface of the laundry, so that the laundry is pressed with a uniform pressure.

  The operation of the squeezing type dehydrator shown in FIG. 7 will be described. Laundry is put into the basket 2 from the chute 41 in a state where the pressing body 1 is raised, and then the pressing body 1 is lowered to contact the receiving plate 5. Press the laundry in between to squeeze out moisture. Next, the pressing body 1 rises to release the pressure in the basket 2, and the peripheral wall 17 rises with a slight delay. Next, the conveyor 4 is driven to convey the dehydrated laundry to the dryer. By repeating this operation, the laundry put in intermittently from the chute 41 is dehydrated.

  The squeezing operation by the pressing body 1 lowers the pressing body 1 with a weak force, and then raises the oil pressure supplied to the hydraulic cylinder 8 to a predetermined final pressure, and then holds the final pressure for a predetermined holding time. It is done by the action of doing. In order to solve the problem that the laundry after dehydration adheres to the elastic pressing surface in Patent Document 1, the applicant of this application presses the pressing body with a weak force on the upper surface of the laundry in the first step. In the next second step, the pressing body is slightly raised to introduce air between the elastic pressing surface and the laundry, and in the next third step, the pressing body is urged with a predetermined force and speed to wash the laundry. In addition, it is proposed to perform the dehydration in the third step after repeating the first step and the second step a plurality of times.

Further, the patent document 2 proposes that the lowering speed of the pressing body 1 is controlled by driving a positive displacement hydraulic pump that supplies hydraulic oil of the hydraulic cylinder 8 with a servo motor that is speed feedback controlled. is doing.
JP 2001-293293 A Japanese Patent Laid-Open No. 2001-232094

  The press-type dehydrator is often used for dehydration of laundry washed by a continuous water washer. The continuous water washing machine is provided with a plurality of washing tubs, and the laundry already washed is scooped out and discharged from the last-stage washing tub with a rotating guide called a scoop. At this time, a considerable amount of washing water is discharged. (Rinse water) is discharged together with the laundry.

  On the other hand, the basket of the squeezing type dehydrator requires a considerable strength to withstand the internal pressure generated during dehydration, and the peripheral wall 17 and the receiving plate 5 must have a thickness of several centimeters or more. The opening area cannot be increased too much.

  In order to perform dehydration under such conditions in a short time, it is necessary to increase the dehydration rate by increasing the descending speed of the pressing body 1 or increasing the pressing force. However, if the dehydration rate is increased, the resistance of water increases in proportion to the square to the fourth power of the flow rate, so that a large pressure gradient is generated inside the laundry that is agglomerated due to the pressure difference. Large strain (stress) or stress acts on the laundry.

  Linen products such as towels and sheets for commercial use (used in hotels and hospitals) that are washed in a continuous washing machine are washed frequently, so even if there is a slight increase in stress during one dehydration The life of the laundry is greatly reduced by repeated washing. It is very important to reduce the stress acting on the laundry during dehydration.

  The press-type dehydrator has a problem that it is easy to apply an excessive force to the laundry during dehydration, and the life of the laundry is reduced due to repeated stress associated with repeated washing. In particular, if the laundry is thrown into the squeeze-type dehydrator and squeezed in a state where no force is applied uniformly to the laundry, a strong stress is applied to a part of the laundry, and the laundry in that part The stress acting on the fabric further increases, causing damage to the laundry such as tearing. Further, when dehydration is performed in an unbalanced state, there is a problem that causes variation in the dehydration rate.

  In the squeezing type dehydrator, after the dehydration process is completed, the hydraulic cylinder 8 that urges the pressing body 1 downward is depressurized, and then the pressing body 1 rises. At this time, when the laundry is stuck to the pressing surface 13 and rises together, the peripheral wall 17 of the basket also rises, and then the peripheral wall 17 falls by its own weight, and the basket 2 and the conveyor belt may be damaged by the impact at the time of dropping. . In addition, if the laundry remains elevated together with the pressing body 1 and the peripheral wall 17 of the basket, the conveyance of the dehydrated laundry is hindered.

  This invention reduces strain and stress applied to the laundry when the laundry is dehydrated with a squeeze-type dehydrator, and prevents as much as possible a reduction in the life of the laundry caused by washing, It is an object of the present invention to obtain technical means capable of improving the dewatering rate without increasing the stress applied to the laundry when used with a continuous washing machine having a fast washing cycle.

  The present invention solves the above-mentioned problems by squeezing the laundry by gradually raising it to a predetermined final pressure while pulsating (hammering) the pressing force applied when the laundry is pressed and dehydrated. It is. Due to the pulsation of the pressing force, dehydration can be performed while releasing the stress applied to the laundry when the pressure increases, and damage to the laundry is reduced. The pulsation of the pressing force is performed by increasing the oil depression force applied to the hydraulic device that raises and lowers the pressing body and then decreasing it once, or by repeatedly raising the pressing body that has lowered along with the pressurization.

  The invention of claim 1 of the present application includes a basket 2 formed of a bottom wall and a peripheral wall capable of separating the lower edge from the bottom surface, a pressing body 1 inserted into the basket from above, and the pressing body. The present invention relates to an operation method for dehydrating laundry with a squeezing type dehydrator equipped with a hydraulic device 8 that raises and lowers.

  At least one of the bottom surface and the peripheral wall of the basket 2 has water permeability. Water permeability can be imparted by forming the bottom surface with the conveyance surface of the conveyance belt 4 having water permeability, and forming the bottom surface and the peripheral wall with a punching metal, a metal plate provided with a large number of through holes, or a metal cylinder.

  The operation method of the squeezing type dehydrator according to the invention of claim 1 of the present application is that the laundry is put into the basket 2 together with the washing water, and the pressing body 1 is lowered by the oil pressure to lower the pressing body and the bottom surface of the basket 2. In the operating method of the laundry type press dehydrator that pressurizes and dehydrates the laundry and the washing water, the initial pressure or initial pulsation stroke of the hydraulic device 8 that raises and lowers the pressing body 1, the pulsation pressure during pressurization, The pressurizing pulsation stroke, final pressure, pressurization time, and holding time are set in the controller 36 in advance, the oil pressure is pulsated 50 with an amplitude corresponding to the initial pressure or the initial pulsation stroke in the initial step a, and the pressurization time is set. The pressure increasing step b for increasing the oil pressure to the final pressure includes a pulsation operation 51 for pulsating the oil pressure with an amplitude corresponding to the pulsation pressure during pressurization or the pulsation stroke during pressurization, In the above holding time held at the final pressure, and then it is characterized in that the raising the pressing body.

  Moreover, the operation method of the compression type dehydrator according to the invention of claim 2 of this application is the operation method having the above characteristics, wherein one or a plurality of intermediate pressures and pulsation time are provided between the initial pressure P0 and the final pressure Pm. Or the number of pulsations is set in the controller 36 in advance, and the pulsation time is set at an amplitude corresponding to the pulsation pressure during pressurization or the pulsation stroke during pressurization when the oil pressure reaches the intermediate pressure during the pressurization step. Or the number of pulsations is pulsated.

  In the pulsation operation (hammering), after pressurizing to a set pressure (initial pressure P0, intermediate pressure P1, P2, P3 or final pressure Pm), the pressure is reduced to a preset lower limit value corresponding to each pressure, Alternatively, it is performed by repeating the operation of decreasing the pressure to a pressure corresponding to a preset pressure difference and increasing the pressure again to the original pressure (pulsation operation by pressure control). Alternatively, the position of the pressing body 1 when it is squeezed at the initial pressure, intermediate pressure or final pressure is read, the pressing body 1 is raised by a preset stroke from that position, and then returned to the original pressure or position again. Performed by repeating the operation (pulsation operation by position control). The pulsation operation by pressure control and the pulsation operation by position control may be switched in the middle. It is preferable that the pulsation period can be changed according to the material of the laundry.

  The pulsation pressure is set as the upper limit or lower limit pressure of the pulsation, or as the pressure difference between the upper limit and the lower limit. The timing for starting the pulsation operation can be set by the elapsed time from the start of the operation of the dehydrator or the hydraulic device 8, the oil pressure during the pressurization, or the position or stroke of the pressing body 1. Further, the operation period of the pulsation operation can be set by a timer, the number of pulsations, the oil pressure when the pulsation operation is finished, the position or stroke of the pressing body, and the like.

  By performing the pulsation operation with a weak initial pressure before the pressurizing step, it is possible to obtain an effect of correcting the bias of the inputted laundry in the basket. The pressurizing pattern including the pulsation operation can be performed in various patterns according to the laundry material. For example, a pattern in which the pressure at that time is maintained at a constant cycle during the pressure increasing process to perform a pulsating operation, a pattern in which the pressure is gradually increased while pulsating, and an initial pressure is gradually increased even in the pulsation in the initial process The pattern and pulsation are performed only at the end of the initial process and the pressure increasing process, and the pulsation is not performed in the process between them.

  The operation method of the squeezing type dehydrator according to the invention of claim 3 of the present application is the operation method having the above characteristics, wherein after the pressure holding step c is completed and the pressing force of the pressing body 1 is released, the pressing body 1 is repeated several times to give vibration to the laundry, and the pulsation operation 52 is performed to promote the separation of the dehydrated laundry adhered to the pressing surface 13.

  After the pressure holding process is completed and the pressing force of the pressing body 1 is released, the control for moving the pressing body 1 up and down is the same as the method of pulsating the pressing body 1 in the initial process or the pressure increasing process. This can be realized later. By the pulsation operation after releasing the pressure, it is possible to prevent the laundry from adhering to the lower surface (pressing surface) 13 of the pressing body, thereby preventing various problems associated with the adhesion of the laundry to the pressing body 1.

  The operation method of the squeeze type dehydrator according to the invention of claim 4 of the present application is the operation method having the above characteristics, wherein the oil pressure is driven by a servo motor 34 whose feedback control is performed on the rotation speed and the rotation torque. It is supplied by a positive displacement hydraulic pump 30 that can rotate in the forward and reverse directions.

  By this method, the degree of freedom and accuracy of control of the pressing force of the laundry are improved, and it becomes possible to perform a pressure increasing operation and a pulsating operation according to the material and type of the laundry. Further, by driving the hydraulic device 8 in this way, the direction switching valve, pressure reducing valve, throttle valve, etc. required in the conventional hydraulic circuit become unnecessary, the number of hydraulic parts is greatly reduced, and the hydraulic circuit is reduced. It can be simplified. The switching of the pressing body 1 is performed by forward-reverse rotation of the servo motor 34, the speed control of the pressing body 1 is performed by the rotational speed control of the servo motor 34, and the pressing force is controlled by the torque control of the servo motor 34.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a view showing the main part of the squeeze-type dehydrator with the pressing body 1 and the basket 2 in cross section, as viewed from the right side of FIG. 7 (downstream side of the conveyor). In this figure, the conveyor belt 3 is schematically shown by a line segment indicating its installation position. The conveyor 4 is provided so that the conveyor belt slides on the upper surface of a receiving plate 5 fixed to an apparatus frame (not shown).

  Four tie rods 6 are erected on both sides of the conveyor belt on the receiving plate 5, and an upper plate 7 is fixed to the upper end thereof. A hydraulic cylinder 8 is mounted on the upper plate with the rod 9 facing downward. . A pressing body 1 is fixed to the lower end of the rod 9. The pressing body 1 is formed of a base disc 10 and a dish-like rubber film 11 having an upper peripheral edge fixed to the peripheral surface thereof in an airtight state, and is formed between the base disc 10 and the dish-like rubber film 11. The fluid chamber 12 is filled with fluid (water), and the pressing force of the rod 9 is transmitted to the elastic pressing surface 13 which is the lower surface of the dish-like rubber film 11. The elastic pressing surface 13 in the drawing has a shape curved upward in a partial spherical shape.

  The illustrated pressing body 1 includes a conduit 15 for introducing air to the lower surface of the elastic pressing surface 13. The conduit 15 is opened to the atmosphere via a check valve 16. The check valve 16 is provided in a direction in which air flows into the lower surface of the elastic pressing surface 13 when the lower surface side of the elastic pressing surface 13 becomes negative pressure.

  A cylindrical peripheral wall 17 is mounted on the conveyor belt 3 above the receiving plate 5 so as to be movable up and down while being guided by the tie rod 6. The pressing body 1 has a dimensional relationship in which the pressing body 1 is fitted into the inner periphery of the peripheral wall 17 so as to be movable up and down. The peripheral wall 17 can be lifted upward by an air cylinder (not shown). The lower edge of the peripheral wall 17 is pressed against the upper surface of the conveyor belt 3 by its own weight, and is moved up by the air cylinder when the conveyor belt 3 is driven to carry out the dehydrated laundry.

  The peripheral wall 17 is a metal cylinder having a thickness of about 3 cm, and is provided with a number of drain holes (not shown) penetrating from the inner periphery to the outer periphery. When the pressing body 1 is moved downward and the laundry in the basket containing a large amount of moisture is pressed, water flows out from the drain hole. In an actual apparatus, an outer cylinder is provided outside the peripheral wall 17, and water flowing out from the drain hole is discharged from a drain pipe (not shown) through a space between the peripheral wall 17 and the outer cylinder.

  As shown in FIG. 5, a drain port 20 is provided at the center of the flat upper surface of the receiving plate 5, and water guide grooves 21 are formed radially from the drain port. The upper surface of the receiving plate 5 is formed by a smooth punching metal 22 having a surface that covers the drain port 20 and the water guide groove 21. This structure receives the pressing force acting on the receiving plate 5 from the pressing body 1, prevents damage to the transport belt due to the pressing force, and smoothly drains the washing water squeezed out by the pressing operation. This structure is suitable.

  The drain port 20 is formed as a recess in the central portion of the receiving plate 5, and a suction passage 24 connected to the ejector 23 communicates with the drain port. The ejector 23 is a device that generates a negative pressure in the suction passage 24 by allowing a driving fluid 26 such as air or water to flow from the driving fluid inlet 25 at a high speed, and the sucked water flows out together with the driving fluid 26. 28 flows out. That is, the squeezing type dehydrator shown in the figure has a structure capable of actively sucking out the washing water from the bottom surface of the basket 2 by the negative pressure generated by the ejector 23. A vacuum pump can be provided instead of the ejector.

  The lower end of the linear scale 27 is fixed to the pressing body 1, and the position of the pressing body 1 can be detected by the linear scale 27.

  As shown in FIG. 6, hydraulic oil is supplied to the hydraulic cylinder 8 by a hydraulic pump 30 that can rotate forward and reverse. A pressure sensor 32 is provided in the hydraulic oil passage 31 in the direction in which the rod 9 is lowered. The pressing force when the pressing body 1 presses the laundry is detected by the pressure sensor 32. The pressing force of the pressing body 1 can also be detected by a structure in which a pressure sensor for detecting the pressure of the fluid chamber 12 is provided on the pressing body 1 or a structure in which a load cell is attached to the rod 9 of the hydraulic cylinder.

  The hydraulic pump 30 is rotationally driven by a servo motor 34 having a rotor shaft directly connected to the pump shaft. The servo motor 34 is controlled by a controller (servo controller) 38 via a servo driver 35. The rotation speed, rotation speed, and torque of the servo motor 34 are controlled based on set values set in the sequencer (controller) 36.

  The set values of the initial pressure, the pulsation pressure during pressurization, the final pressure, etc. for performing the dehydrating operation described later are set in the memory of the pressure control unit of the sequencer 36, and the initial pulsation stroke and the pulsation stroke during pressurization are set. Etc. are set in the position control unit. The boosting time, holding time, etc. are set in the timer of the sequencer 36. The set values of these sequencers 36 are changed by a mode switching signal, a set value change signal, or the like from the touch panel 37. Detection signals of the linear scale 27 and the pressure sensor 32 are given to the controller 38 as feedback signals. The controller 38 receives the rotation speed, rotational speed and torque command values given from the sequencer 36, and the linear scale 27 and pressure. The servo motor 34 is controlled based on the difference signal from the measurement value detected by the sensor 32.

  As described above, the hydraulic cylinder 8 is controlled by directly connecting the servo motor 34 capable of feedback control of the rotational speed and the rotational torque to the positive displacement hydraulic pump 30 capable of rotating in the forward and reverse directions to control the operation of the hydraulic cylinder 8. The hydraulic circuit to be driven can be simplified, and an accurate pressing operation and pulsating operation with good responsiveness can be realized.

  Next, a preferred example of the hydraulic pattern supplied to the hydraulic cylinder 8 in the operation method of the present invention will be described with reference to FIGS. In these figures, time is plotted on the horizontal axis and oil pressure is plotted on the vertical axis. A is the initial process, b is the pressure increasing process, c is the pressure holding process, d is the pressure releasing process, and e is the pressing body. Reference numeral 1 denotes a return process for returning to the raised position. P0 on the vertical axis is an initial pressure, P1, P2, and P3 are first to third intermediate pressures, and Pm is a final pressure (holding pressure). Reference numeral 50 denotes an initial pulsation operation, and reference numeral 51 denotes a pressurization pulsation operation. The period of this pulsation operation is set by the number of vibrations or the vibration time. In addition, f in the figure is an operation section of the ejector 23.

  In the example of FIG. 1, the intermediate pressure is set to two stages, FIG. 3 is set to three stages, and FIG. 3 is not set to the intermediate pressure (therefore, the pulsation is 2 in the initial process and immediately before the pressure holding process. However, an operation pattern in which an intermediate pressure of one or more stages is set is also possible.

  In the example of FIG. 1, after the laundry is put into the basket 2, hydraulic pressure is supplied to the oil chamber on the side opposite to the rod of the hydraulic cylinder 8 to lower the pressing body 1, and the oil pressure reaches the initial pressure P <b> 0. After that, the pulsation operation 50 is performed for the set number of times or set time between the initial pressure and the zero pressure. After this pulsation operation 50, the pressure increasing process b is started in which the supply pressure to the hydraulic cylinder 8 is gradually increased to the final pressure Pm. Then, when the intermediate pressures P1 and P2 are reached in the middle of the pressure increasing process, and when the final pressure Pm is reached, the supply oil pressure is pulsated 51 to hammer the pressing body 1 (impact like hammering) Operation to give a pressing force to the laundry).

  And after a pressurization process is complete | finished, the final pressure Pm is hold | maintained for predetermined time, and the wash water which permeate | transmitted into the fiber of the laundry is squeezed out (pressure holding process). Thereafter, the hydraulic pressure supplied to the oil chamber on the lowering side of the hydraulic cylinder 8 is released (pressure releasing step), and further, the hydraulic pressure is supplied to the side that raises the rod to raise the pressing body 1 (returning step).

  In the example of FIG. 1, the pulsation operation 52 is further performed after the pressure release step d is completed. The pulsating operation 52 is performed by pulsating the hydraulic pressure on the side that raises the pressing body 1, and a negative pressure is generated between the pressing body 1 and the lump of laundry after dehydration by the pulsation. In this case, air flows from the conduit 15 shown in FIG. 4 to prevent the laundry from adhering to the pressing surface 1 of the pressing body.

  That is, by raising the pressing body 1 after such a pulsating action 52, it is possible to prevent an undesired behavior in which a lump of dehydrated laundry rises together with the pressing body 1 and then falls. .

  FIG. 1 shows an example in which the pulsation in the boosting step is performed while keeping the pressure constant. FIG. 2 shows an example in which the boosting operation is continued even during the pulsation. The timing for starting pulsation during boosting can be set by setting intermediate pressures P1, P2, and P3, or can be set by a timer that measures the time from the start of boosting. When the pulsation operation is performed while changing the pressure in this way, it is convenient to set the lower limit value of the pulsation by the amplitude (pressure difference or stroke).

  By pulsating the hydraulic pressure supplied to the hydraulic cylinder 8 that urges the pressing body 1 as described above, the pressing body 1 can be hammered. The hammering 50 in the initial process is performed in a state where the laundry is floating in the washing water, so that the effect of uniforming the uneven distribution of the laundry in the basket 2 is exerted, and the laundry is at the time of pressurization and pressure holding. It is particularly effective in avoiding large stress acting on a part of

  In addition, when the pressing force is eased by the hammering 51 during pressurization, the local stress caused by the wrinkles and local overlap of the laundry is diffused to reduce local damage to the laundry. can do. In addition, the pulsation operation 52 after depressurization prevents the phenomenon that the laundry or the peripheral wall 17 of the basket after dehydration adheres to the pressing body 1 and falls after the pressing body 1 ascends as described above. can do.

  In addition, the washing water in the basket 2 is actively sucked and discharged by the ejector 23 or the vacuum pump from the initial process or the initial process to the initial stage of the pressure increasing process, so that a large amount of space is surrounded by the laundry cloth. When the water and air are pressed while remaining, the laundry can be prevented from being damaged by the water and air passing through the fabric rapidly. In addition, when the water content in the initial stage of dehydration is very high, the water in the basket 2 is actively sucked and discharged by the ejector 23 or the vacuum pump, so that the dehydration time can be significantly shortened.

  The action of reducing the damage to the laundry due to the hammering of the pressing body 1 is effectively exhibited at the initial stage and the final stage of the pressing process. Therefore, as shown in FIG. 3, as the simplest operation method of the present invention, a method in which the pulsation operation is performed only at the end of the initial step a and the boosting step b can be given as another example of the preferable operation method. .

Diagram showing first example of operation pattern Diagram showing second example of operation pattern Diagram showing third example of operation pattern Cross-sectional side view showing an example of a compression dehydrator Partial destruction plan view of backing plate Block diagram showing drive system of pressing body Schematic side view showing the squeezing dehydrator and conveyor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Press body 2 Basket 3 Conveying belt 5 Receptacle 8 Hydraulic cylinder
17 Perimeter wall
30 Hydraulic pump
34 Servo motor
50,51,52 Pulsating motion (hammering)
a initial process b pressure increasing process c pressure holding process d pressure releasing process e return process

Claims (4)

A basket (2) formed with a peripheral wall (17) capable of separating the bottom surface and the lower edge from the bottom surface, a pressing body (1) inserted from above into the basket, and raising and lowering the pressing body A washing machine and washing water between the pressing body and the bottom surface by lowering the pressing body with hydraulic pressure. It is an operation method of a press-type dehydrator for laundry to be dehydrated by pressurization,
The initial pressure or initial pulsation stroke, pulsation pressure during pressurization or pulsation stroke during pressurization, final pressure, pressurization time and holding time are set in the controller (36) in advance, and the oil pressure is set to the initial pressure in the initial step (a). Pressure or pulsation with an amplitude corresponding to the initial pulsation stroke (50), and in the pressure increasing step (b) for increasing the oil pressure to the final pressure over the pressure increasing time, A pulsation operation (51) that pulsates with an amplitude corresponding to the pulsation stroke at the time of pressurization is included, the holding time is held at the final pressure in the pressure holding step (c), and then the pressing body is raised. , Operation method of squeeze type dehydrator.   One or more intermediate pressures and a pulsation time or number of pulsations are set in the controller in advance between the initial pressure and the final pressure, and when the oil pressure reaches the intermediate pressure during the pressure increasing step, 2. The operation method of a squeeze type dehydrator according to claim 1, wherein the pulsation time or the number of pulsations is pulsated with an amplitude corresponding to a pulsation pressure during pressurization or a pulsation stroke during pressurization.   After releasing the pressing force of the pressing body (1) after the pressure-holding step was finished, the vertical movement of the pressing body (1) was repeated several times to give vibration to the laundry and adhered to the pressing surface (13). The operation method of the squeezing type dehydrator according to claim 1 or 2, characterized in that a pulsation operation (52) that promotes peeling of the dehydrated laundry is performed.   The hydraulic pressure is supplied by a positive displacement hydraulic pump (30) driven by a servomotor (34) whose feedback is controlled in rotational speed and rotational torque. Or the operation method of the pressing-type dehydrator of 3.

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