JP4354306B2 - Inverter-equipped squeezing dehydrator and dehydrating method thereof - Google Patents

Description

  The present invention relates to a dehydrator that presses laundry containing water such as sheets and towels after washing with a pressurizing body descending from above and removes moisture by pressing.

A conventional compression dehydrator will be described with reference to FIGS. 1 and 2.
FIG. 1 is a front view showing an outline of a main body of a conventional squeezing type dehydrator. This compression type dehydrator is combined with a continuous water washing machine or the like, and has been washed with sheets, towels, etc., and has been immersed in water. Used for dehydration.
In FIG. 1, 10 is a lower frame installed on the work floor, 11 is four pillars suspended from the lower frame 10, 12 is an upper frame fixed to the upper part of the pillar 11, and 13 is an upper frame. The hydraulic cylinder 14 is fixed to the center of the cylinder 12 with the rod facing downward, 14 and 15 are respectively the piston and rod of the hydraulic cylinder 13, 16 is the head side oil chamber, 17 is the rod side oil chamber, and 18 is the hydraulic cylinder 13. A large-capacity top valve provided at the upper part, 19 is a pressurizing body fixed to the lower end of the rod 15 and the lower part is formed of an elastic body, 20 is a hydraulic pump unit that is a hydraulic pressure generation source, and 21 and 22 are hydraulic pressures, respectively. A hydraulic pump of the pump unit 20 and a pump motor that drives the hydraulic pump, 23 is an oil tank, and a pipe for driving the hydraulic cylinder 13 is disposed on the upper frame 12. That it is not shown.
Further, 24 is a wide transfer mesh belt through which water can pass, 25 is a driving roll for the mesh belt 24, 26 is a bottomless cylindrical basket having a large number of small holes, and 26a is formed integrally with the basket 26. The insertion port 27 is a laundry, and the basket 26 is supported by a lifting device (hydraulic cylinder) (not shown) provided on the upper frame 12 so as to be movable up and down.

The hydraulic cylinder 13 is a double-acting cylinder, and the pressure receiving area on the head side of the piston 14 is large to obtain a large squeezing force downward, and the rod side pressure receiving area is made as small as possible to increase the speed during ascent. The pump 21 is a positive displacement constant capacity vane pump having a pump for low pressure and large flow rate and a pump for high pressure and small flow rate, and the drive motor 22 is an induction motor for AC commercial power. In addition, the mesh belt 24 has two reciprocating sheets that are reciprocated in order to facilitate replacement, and is superposed on the upper frame upper side, and a drainage plate (not shown) capable of passing water is inserted therebetween.
FIG. 2 is a schematic diagram showing a hydraulic circuit of a drive device for the hydraulic cylinder 13, wherein 28 is a switching valve disposed between the hydraulic pump 21 and the hydraulic cylinder 13, and 29 is disposed between the hydraulic pump and the tank 22. The relief valve 30 is a control device for automatic operation. The relief valve is used to set the hydraulic pressure freely.

The operation of the dehydrator having the above configuration will be described.
The basket 26 is lowered by a lifting device (not shown), and the lower end is placed on the mesh belt 24 supported by the lower frame and the drainage plate. The hydraulic pump unit 20 is started, and the hydraulic oil is circulated through a bypass circuit that returns from the hydraulic pump unit 20 to the hydraulic pump unit 20 via the relief valve 29 and the oil tank 23 to be in a standby state. The pressurizing body 19 is pulled up to the upper standby position by the hydraulic cylinder 13.
The laundry 27 is rinsed from the upstream washing machine, and is poured into the basket 26 together with the rinsing water from the charging port 26a. The injected water passes through the mesh belt 24 and the drainage plate on the lower side of the basket 26 to the lower side. The laundry 27 flows out of the small hole in the side wall of the basket 26 and flows into the basket 26 almost flatly during this time. The automatic operation by the control device 30 starts when the laundry 27 is thrown in. First, the switching valve 28 is opened to supply hydraulic oil from the hydraulic pump 21 to the head side oil chamber 16 of the hydraulic cylinder 13, and the top valve 18 is opened to apply pressure. The pressure body 19 is lowered. The top valve 18 is opened in order to increase the descending speed of the pressurizing body 19 by sucking the operating oil from the oil tank 23 by the weight of the pressurizing body 19, the piston 14 and the rod 15. The hydraulic oil in the rod side oil chamber 17 is discharged to the oil tank 23 through the switching valve 28.

After the pressurizing body 19 descends at a high speed, the top valve 18 is closed, the relief pressure of the relief valve 29 is gradually increased, hydraulic oil is supplied by a low-pressure and large-flow pump, and the laundry 27 is squeezed. Squeeze out the water. Since the lower surface of the pressurizing body 19 is made of an elastic body, even if the upper surface of the laundry 27 is uneven, it can be deformed along the unevenness to press the laundry 27 with a uniform pressure. it can. The squeezed water is discharged laterally through a small hole in the basket 26 and discharged downward through a gap between the mesh belt 24 and the drainage plate. Next, the relief pressure of the relief valve 29 is increased, the hydraulic pump 21 is switched to a high-pressure and low-flow rate pump and dewatered with a large pressing force, and this pressed state is maintained for a while. At this stage, the amount of water contained in the laundry 27 decreases, the descending speed of the pressurizing body becomes extremely small, and the descending amount becomes small.
By switching the switching valve 28, hydraulic oil is sent to the rod side oil chamber 17 of the hydraulic cylinder 13, and the hydraulic oil in the head side oil chamber 16 opens the top valve 18 and is discharged to the oil tank 23 to pull the pressurizing body 19. increase. The force required for pulling up the rod 15 at this time is small, and the pressure receiving area of the rod-side oil chamber 17 is small, so that the ascending speed is increased. Next, the basket 26 is pulled up by the lifting device, the mesh belt 24 is driven by the driving roll 25, and the dehydrated laundry 27 left on the mesh belt 24 is sent to the next step.

JP2001-232094

FIG. 3 shows the pressure (thick line) on the discharge port side of the hydraulic pump unit 20 and the corresponding power consumption (thin line) over the entire process of the dehydration process performed on a certain type of laundry 27 with a conventional dehydrator. It is a graph which shows the condition of change.
The time points 0 to A and the time points G to H are standby times when the switching valve 28 is closed and the hydraulic cylinder 13 is not operating, but the pump unit 20 circulates hydraulic oil through a bypass circuit that passes through the relief valve 29. The so-called idling operation is continued, and standby is performed so that hydraulic oil can be supplied by the switching valve 28 when necessary. This is to prevent a large starting current from flowing every time the pump motor 22 is started and shorten the life of the electromagnetic switch or the like. However, since the hydraulic oil performs invalid work, it is a waste of electric power. .
In addition, the time point E to F is a later pressing process by the high-pressure pump, and the pressing is performed with a large pressure. However, the amount of water contained in the laundry 27 is reduced, and the lowering speed of the pressurizing body 19 is gradually decreased. Is a slight dehydration process, so that the effective work performed by the hydraulic cylinder 13 should be gradually reduced, but the power consumption is not reduced. This is because the descending speed of the pressurizing body 19 is reduced, and excessively supplied high-pressure hydraulic oil is circulated through the bypass circuit passing through the relief valve 29. The work performed by the circulation of a large amount of hydraulic oil at this high pressure is an invalid work and wastes a large amount of power.

An object of the present invention is to provide a squeezing type dehydrator using a general-purpose induction motor for an AC commercial power supply that is low in apparatus cost and running cost.
In order to perform an optimal dehydrating operation according to the type and amount of laundry, a pressure detector for detecting the pressing force, a position detector for detecting the height of the pressurizing body, and a variable speed drive device are provided. An apparatus for controlling the lowering speed according to the position of the pressurizing body has been proposed in Japanese Patent Application Laid-Open No. 2001-232094 as a “pressing dehydrator for laundry”, but this apparatus is complicated and expensive. The purpose of the dehydrator of the present invention is different.

  A conventional hydraulic pump unit composed of a general-purpose induction motor (pump motor) for AC commercial power supply and a positive displacement constant capacity hydraulic vane pump, and driven by this hydraulic pump unit, the pressure receiving area on the rod side of the piston is particularly small. A large-diameter, long-stroke, double-acting hydraulic cylinder, a pressure body fixed to the rod of the hydraulic cylinder and moving up and down and having a lower surface formed of an elastic body, and a controller for performing sequence control In the squeeze type dehydrator that controls the required hydraulic oil pressure and flow rate with a relief valve, as a first method, an inverter is added to the power circuit, and the dehydration process time is divided into a plurality of sections. Specify the relief pressure of the relief valve and the number of driving power cycles of the pump motor. The number of power supply cycles to be specified is the minimum number of cycles that can hold the pressure of a reference pressure pattern described later. As a second method, the relief valve used in the first method is deleted, a pressure sensor is provided at this position, the pressure detected by this pressure sensor is sent to the control device, and the pressure of the reference pressure pattern previously given When the detected value is larger than the reference value, the power cycle number is decreased, and when the detected value is small, feedback control is performed to increase the power cycle number. The number of power cycle limits the upper limit and the lower limit as necessary.

The following effects are obtained by the squeezing dehydrator of the present invention.
(1) Since only an inverter is added to a conventional dehydrator that uses an induction motor for AC commercial power, the equipment cost is relatively low, and one model can be used regardless of the power cycle of the shipping destination. Therefore, the apparatus cost and the management cost can be reduced. Moreover, it can be easily modified and applied to a dehydrator already in operation.
(2) Conventionally, the excess hydraulic fluid supplied to the required amount of hydraulic fluid in the load side cylinder was controlled by circulating the bypass circuit, but this invalid work was reduced by lowering the power cycle of the induction motor. Therefore, the running cost can be reduced. The reduction of invalid work reduces the cooling water of the oil tank and can further reduce the running cost.
(3) The start-up of the induction motor does not cause a large starting overcurrent, so it can be started frequently, so the hydraulic unit can be stopped each time during standby, contributing to a reduction in running costs and noise. it can.

An embodiment of an inverter-equipped squeezing dehydrator of the present invention (hereinafter referred to as the dehydrator or dehydrator of the present invention) will be described with reference to FIGS. 1 and 4 to 6.
The dehydrator of the present invention is basically the same dehydrator as the conventional example with an additional inverter, and the main body is the same as the conventional example shown in FIG. To do. A hydraulic pump unit 20 indicated by a two-dot chain line in FIG. 4 and 5 are schematic diagrams of simplified hydraulic circuits of the dehydrator of the first and second embodiments corresponding to FIG. 2 of the conventional example, respectively.
The dehydrator of the conventional example requires the hydraulic pump unit 20 for 50 cycles or 60 cycles depending on the cycle of the commercial power source in the area to be used. In the dehydrator of the present invention, one cycle, for example, 60 cycles is used. The hydraulic pump unit 20 can be unified. Hereinafter, the dehydrator will be described as a conventional one for 60 cycles.

3, as described above, the pressure on the discharge port side of the hydraulic pump unit 20 and the corresponding change in power consumption over the entire process of the dehydration process performed on a certain type of laundry 27 with a conventional dehydrator. This pressure curve is the most suitable pressure pattern obtained from experience with the laundry 27, and is hereinafter referred to as a reference pressure pattern. Although this reference pressure pattern varies depending on the type of the laundry 27, it is sufficient that the number of the pressure pattern is actually several.
In this reference pressure pattern, the dehydration process (time) is divided into a plurality of appropriate sections, the maximum pressure in each section is regulated by the relief valve 29, and excess hydraulic oil is circulated in the bypass passing through the relief valve 29. Is obtained. In FIG. 3, the pressure curves when operating at the power cycle number of 40, 30, and 20 Hz under the same conditions are indicated by a one-dot chain line, a two-dot chain line, and a three-dot chain line, respectively, and the power consumption during the 40 Hz operation is shown. It is shown by a thin line with a one-dot chain line. The effect on the pressure due to the change in the number of cycles hardly appears in the low pressure dehydration section (sections A to E) in the first half of the dehydration process, and the time delay until the maximum pressure is reached in the high pressure dehydration section (sections E to F) in the second half The maximum pressure is not reached at 20 Hz. On the other hand, the power consumption is reduced with the number of cycles as in the 40 Hz example. Therefore, the closer to the end of the dehydration process, the lower the number of cycles can be driven, and the power consumption can be reduced.
The dehydrator of the present invention reduces the flow rate circulating through the bypass circuit by changing the number of power supply cycles while maintaining the reference pressure pattern.

(Configuration of the first embodiment)
FIG. 4 is a hydraulic circuit diagram of the first embodiment. The only difference is that an inverter 40 is added to the same dehydrator as in the conventional example.

(Operation of the first embodiment)
The operation of the dehydrator of the first embodiment will be described with reference to FIG.
FIG. 6 shows a comparison of power consumption between the dehydration process performed by the conventional dehydrator shown in FIG. 3 and the dehydration process performed by the dehydrator of the first embodiment, and the number of power cycles used in the dehydration process of the first embodiment. The setting status is shown. In the dehydration process of the first embodiment, the process section and the relief pressure applied to the relief valve 29 in each section are the same as in the conventional example, but the number of power cycles applied to the pump motor 22 is not necessarily the same as the section described above. The pump motor 22 is driven with the number of cycles indicated by a broken line in each section divided into a plurality of sections that do not coincide (10 sections in the figure).

The dehydration step is performed in the same manner as in the case of the above-described conventional example, but will be described with the main points.
When the laundry 27 is put in, a photoelectric switch (not shown) works, and the control device 30 starts sequence control of the dehydration process according to a program from a signal from the photoelectric switch. The program is stored in the control device 30 and stores the relief pressure applied to the relief valve 29 and the number of power cycles applied to the pump motor 22 according to the process time. At the time A immediately after the start of the process, the pump motor 22 is turned on, the top valve 18 and the switching valve 28 are opened, and the pressurizing body 19 together with the piston 14 and the rod 15 under its own weight passes from the oil tank 23 through the top valve 18. The hydraulic oil descends at a high speed by the hydraulic oil to be sucked in and the hydraulic oil sent from the hydraulic pump 21. The power supplied to the pump motor 22 gradually increases from 0 Hz to a specified value (40 Hz in the figure), and an excessive starting current does not flow through the pump motor 22. Since the elapsed time of the gradual increase is relatively short (for example, about 1 second), it is indicated by a vertical line in the figure. The gradual increase and decrease in the number of cycles in the subsequent process takes the same time but is indicated by vertical lines in the figure. When the pressurizing body 19 falls between time points A and B, the pressure of the hydraulic oil may be small because the weight of the pressurizing body 19 or the like works, and the output is lowered by reducing the number of cycles of the drive power source.

Next, after closing the top valve 18, switching of the relief pressure of the relief valve 29 is started at the time point B, and the fourth pressure of the high pressure is performed from the time point E through the low-pressure first compression, the second compression, and the third compression. The dehydration is performed until time point F (see the thick broken line in FIG. 3). In the first expression, the second expression, and the third expression, the pressure is sequentially increased at the low pressure stage of the hydraulic pump 22, and in the third expression, the hydraulic pump 22 is switched from the low pressure stage to the high pressure stage. In the dehydration by the low-pressure pump between time points B and E, the process is divided into a plurality of appropriate sections (four sections in the figure), and after the number of cycles is first increased to 60 Hz, the output is lowered to a suitable value. In addition, the peak of the electric power between the time points D to E is a transitional change due to the switching of the hydraulic pump 21 from the low pressure to the high pressure.
In the fourth squeezing between time points E and F, the laundry 27 contains less water and is dehydrated at the stage of receiving a large resistance from the load side, and the pressurizing body 19 requires a large pressing force but the descending speed is small. This is a process that conventionally consumes a large amount of wasted power because the characteristics on the load side and the characteristics on the hydraulic pump unit 20 side do not match. In this section, the process is divided into a plurality of appropriate sections (three sections in the figure), and the number of cycles is first increased to 60 Hz in order to maximize the output of the pump motor 22, and then the descending speed of the pressurizing body 19 is increased. As it slows down, the output is lowered to an appropriate value. In this section, the flow rate of hydraulic oil may be small, and the process time is long, so the power saving is great.
Since the hydraulic pump 21 has a limit on the minimum number of rotations allowed, it is necessary to determine the lower limit of the number of power cycles instructed to the pump motor 22 so as not to violate this limit.
Next, between time points F and G, the switching valve 28 is switched to pull up the pressurizing body 19 and the basket 26 is raised. At time point G, the power source of the hydraulic pump unit 20 is closed, and no power is used until the next dehydration step. To wait. This section is the same as the conventional process, and the cycle number may remain 60 Hz.
The conventional power consumption curve (upper thin line) shown in FIG. 6 and the area enclosed by the power consumption curve (lower thick line) of the present invention (hatched portion in the figure) indicate the amount of power that can be saved. According to experiments, the amount of power that can be saved is 40% or more of the conventional amount of power.

(Configuration of the second embodiment)
FIG. 5 is a hydraulic circuit diagram of the second embodiment. The relief valve 29 of the first embodiment is omitted, and a pressure sensor 45 is provided in the oil pipe at this position. The pressure sensor 45 sends the detected pressure value to the control device 30. The control device also stores a reference pressure pattern and compares it with the pressure value sent from the pressure sensor 45 if there is a difference. The number of power supply cycles is calculated so as to be zero, and means for instructing the inverter 40 is provided. The relief valve 29 may be left if necessary, but the relief pressure need not be variable.

(Operation of the second embodiment)
Since the dehydration process is performed in the same manner as in the first embodiment, only the differences will be described below.
A reference pressure pattern is given to the control device 30 instead of the relief pressure for each section given in the case of the first embodiment. Further, an upper limit and a lower limit of the number of power cycles output from the inverter 40 are given as necessary.
When the dehydration process is started, the control device 30 compares the detected pressure value sent from the pressure sensor 45 with the pressure value of the corresponding reference pressure pattern at any time or at an appropriate time interval, and if there is a difference, the difference becomes zero. The number of cycles is calculated and the inverter 40 is instructed. Accordingly, since the hydraulic pump unit 20 supplies the hydraulic oil without excess or deficiency while maintaining the pressure of the reference pressure pattern faithfully, the invalid work that circulates the bypass circuit is more efficiently removed than in the first embodiment. I can do it. Note that if the pressure of the hydraulic oil increases abnormally during operation, the overload valve moves.
The one-dot chain line in FIG. 6 shows an example of power consumption when the operation is performed with the upper and lower limits of the number of power supply cycles restricted, and the amount of power that can be saved is greater than in the case of the first embodiment.

It is a front view which shows the outline of the main-body part of the conventional pressing-type dehydrator. It is a typical hydraulic circuit diagram of the conventional squeezing type dehydrator. It is a graph of the oil pressure with respect to the process time of the conventional pressing type dehydrator, and power consumption. 1 is a schematic hydraulic circuit diagram of a squeezing dehydrator according to a first embodiment of the present invention. It is a typical hydraulic circuit diagram of the expression type dehydrator of the 2nd example of the present invention. It is a graph which shows the power consumption with respect to the process time of the pressing-type dehydrator of this invention, the number of power supply cycles, and the power consumption of a prior art example.

Explanation of symbols

10: Lower frame 11: Pillar 12: Upper frame 13: Hydraulic cylinder 14: Piston 15: Rod 16: Head side oil chamber 17: Rod side oil chamber 18: Top valve 19: Pressurizing body 20: Hydraulic pump unit 21: Hydraulic pressure Pump 22: induction motor (pump motor)
23: Oil tank 24: Mesh belt 25: Drive roll 26: Basket 26a: Loading port 27: Laundry 28: Switching valve 29: Relief valve 30: Controller 31: Commercial power supply 40: Inverter 45: Pressure sensor

Claims (4)

  A pressurizing body whose lower surface is formed of an elastic body, a hydraulic cylinder for raising and lowering the pressurizing body, a constant displacement hydraulic pump, an induction motor for driving the constant displacement hydraulic pump, and a discharge port of the constant displacement hydraulic pump In a dehydrator that comprises a relief valve provided on the side and a control device, and depresses and dehydrates the laundry containing water by lowering the pressurizing body, and an inverter is attached to the power circuit of the induction motor, An inverter-equipped squeeze-type dehydrator, wherein the controller controls the set pressure of the relief valve and the number of cycles of the drive power source of the induction motor.   The pressure type dehydrator according to claim 1, wherein the relief valve is deleted, a pressure sensor is newly provided in an oil pipe at a position where the relief valve is located, and the control device detects a detected pressure value sent from the pressure sensor. And a means for calculating a difference between pressure values of a reference pressure pattern given in advance, and controlling the number of cycles of the induction motor so that the difference becomes zero. Type dehydrator.   The inverter-equipped squeeze-type dehydrator according to claim 1, wherein the induction motor is stopped in the standby section where the pressurizing body is raised, the process section is divided into a plurality of appropriate sections in the dehydration process section, and each divided section The control device uses an inverter to drive the induction motor to perform dehydration using a program in which relief pressure and power cycle are appropriately specified so that invalid work performed through the relief valve in the engine is minimized. Squeeze-type dehydration method.   The inverter-equipped squeeze-type dehydrator according to claim 2, wherein the induction motor is stopped in a standby section where the pressurizing body is raised, and a program specifying a pressure of a reference pressure pattern is used in the dehydration process section. A squeeze-type dewatering method, wherein the number of power supply cycles is controlled so that a detected pressure value sent from a sensor approaches a pressure value of the reference pressure pattern, and the induction motor is driven by an inverter to dehydrate.

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